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Biomedical subjects

A Weber

Publications and source records attributed to A Weber.

At least 469 records · Page 26Linked to original sources
PubMed1985

[Crohn's disease in children and adolescents].

93 children and adolescents with Crohn's disease have been studied. Terminal ileum (25.8%) and ileum and colon (61.3%) were the most common sites of involvement as determined by X-ray examination. The mean age at the time of diagnosis was 13.2 years. A familial incidence of chronic inflammatory bowel disease was found in 12 patients (12.9%). The most common symptoms were: abdominal pain, anorexia, lassitude, diarrhea, loss of weight. Weight below the third percentile, pain on abdominal palpation, anal lesions, mouth ulcers and clubbing of the fingers were the most common clinical signs at the time of diagnosis. Growth retardation (below the third percentile) was present in 22 of 79 children (27.8%) with a mean follow-up of 40 months. 16 patients out of 75 had initial rectal biopsies with histologic changes characteristic of Crohn's disease. 27 patients had surgical treatment; six of them experienced a relapse within a mean period of 26.7 months. Lastly, the authors show that continuous elemental enteral alimentation (CEEA) during 3 weeks induces a remission. CEEA on a longer period is specially targetted to the treatment of growth retardation.

Adolescent↗
PubMed1985

Irritating and annoying effects of passive smoking.

The acute irritating and annoying effects have been investigated in field and laboratory studies in relation to the concentration of some smoke components in the air. At the workplace 30 to 70% of the indoor CO, NO and particle concentrations are due to tobacco smoke; 25-40% of the employees are disturbed and annoyed by smoke, one quarter suffers from eye irritations at work. Subjective eye, nose and throat irritations and eye blink rate increase with increasing smoke concentration as well as with increasing exposure duration. Irritations are mainly due to the particulate phase of environmental tobacco smoke, whereas the gas phase is to a large extent responsible for annoyance. It is concluded that an average healthy person can be exposed to an acceptable cigarette smoke level which produces a carbon monoxide concentration of 1.5 to 2.0 ppm. Above these limits, counter-measures to protect passive smokers are necessary. The required fresh air supply values are presented.

Blinking↗
PubMed1985

[Occurrence of Campylobacter jejuni in animals and its significance for the human].

The frequency of human infections caused by Campylobacter (C.) jejuni is thought to be at present as significant as that of infections with salmonella. The epidemiology of human infections with C. jejuni is not well understood, although numerous species of animals are an important reservoir for this microorganism. In an overview the occurrence of C. jejuni at different domestic animals and pets is described. There is also given a report about possible direct and indirect ways for the infections from animals to man.

Animals↗
PubMed1984

Lithocholic acid-cholesterol interactions in rat liver plasma membrane fractions.

This study was designed to elucidate the steps involved in the incorporation of lithocholic acid and the increase in cholesterol in liver plasma membranes after lithocholic acid injection. In vitro, cholesterol incorporation or binding to liver plasma membrane fractions enriched in bile canalicular structures occurred only when cholesterol was added simultaneously with lithocholic acid. The addition of cholic acid did not prevent the incorporation or binding of lithocholic acid and of cholesterol. However, when cholic acid was incubated with membranes already containing lithocholic acid and cholesterol, the ratio of cholesterol to lithocholic acid increased from 2 to more than 3 via a reduction of lithocholic acid. The binding of lithocholic acid and cholesterol to membranes rose 5-fold in the presence of cytosolic proteins. By electron microscopy the canalicular membrane structures with a high cholesterol content exhibited few microvilli, and their lumen appeared to have collapsed. These data suggest that simultaneous interaction of lithocholic acid and cholesterol, and not prior incorporation or binding of lithocholic acid to the membrane, may be a prerequisite to cholesterol accumulation in the membrane.

Animals↗
PubMed1984

Calcium dependence of villin-induced actin depolymerization.

"Cutting" of actin filaments by villin was evaluated from the time course of filament depolymerization. Depolymerization was initiated by diluting polymerized actin, labeled with a fluorescent probe on either lysine-374 or cysteine-375, to a concentration well below the critical into a medium containing free villin and various concentrations of calcium (in addition to potassium and magnesium). It was observed that at high calcium concentrations (200 microM) the time course of depolymerization could not be described by the single exponential that defines it at low calcium and low villin levels. Instead, at high calcium, the exponent increased with time and the rate of depolymerization became greater than that of controls in the absence of villin. This contrasts with the inhibition of depolymerization by villin at low calcium. The latter inhibition is a consequence of the capping of the barbed filament end by villin as are the inhibition of filament elongation and the elevation of the critical concentration. Evidence is presented that the effects of villin at high calcium are the result of cutting of the actin filaments by villin. It thus appears that different calcium binding sites control capping and cutting and that the calcium binding sites regulating cutting have a much lower affinity for calcium than the sites regulating capping of the barbed filament ends.

4-Chloro-7-nitrobenzofurazan↗
PubMed1984

Maintenance of immunocytologically identified Purkinje cells from mouse cerebellum in monolayer culture.

Purkinje cells were identified in monolayer cultures obtained from trypsin-dissociated cerebella of embryonic and early postnatal mice by the Purkinje cell-specific monoclonal antibodies PC1, PC2, PC3 and UCHT1. These cells also expressed the neuronal marker L1 antigen but not the glial markers, glial fibrillary acidic protein or 04 antigen. They also expressed tetanus toxin receptors, PC4, M1 and Thy-1 antigens. Survival of Purkinje cells was best: (a) when cerebella were taken from mice not older than one day of age: (b) when cells were seeded at higher plating densities; and (c) cultured in chemically defined medium which facilitates the survival of neurons. No Purkinje cells could be detected in cultures from mice older than 6 days. PC1 antigen expression developed in vitro on the same time scale as in vivo, i.e. it was first detectable at the equivalent of postnatal days 3-4. At this stage cell bodies had a size of 13-14 micron in diameter and few processes. Dendrite-like arborizations, with more than one primary dendrite, extension of usually only one thin and long (0.5-1.6 mm) axon-like process and collaterals directed preferentially towards other Purkinje cells, developed with time in culture until the final form was reached by the equivalent of approximately day 16. Cell body size was 18-19 micron in diameter at this stage. Cell shapes were reminiscent of those described in certain cerebellar mouse mutants and in experimentally produced agranular cerebella. Many ultrastructural features of these cells correlated with those described for the in vivo counterpart. However, there was a lack of spiny branchlets and abnormally long persisting somatic spines. Synaptic contacts of the 'en passant' type could be seen at the Purkinje cell soma. Gray type I synapses were seen on Purkinje cell dendrites and spines.

Animals↗
PubMed1984

Effect of villin on the kinetics of actin polymerization.

The effect of villin on the critical concentration of actin and on the kinetics of its polymerization has been measured. In the presence of villin and 10 microM calcium, the critical concentration of actin increased from 0.2 to 0.9 microM. This effect of villin on the critical concentration was shown to be the result of its well-documented ability to block the "barbed" end of actin filaments, i.e., the "high-affinity end" of a polymer with a different monomer binding constant at each end. Thus, below 0.8 microM actin polymerization was prevented when the ratio of villin to actin was about 1 in 1000. Furthermore, the effect of villin was saturable; i.e., the critical concentration remained constant with increasing villin concentration once the maximal change had been obtained. In addition, fragmentation of actin filaments previously capped with villin, producing uncapped filaments, caused a rapid, transient fall of the monomer concentration. With the disappearance of the uncapped filaments the actin monomer concentration returned to that measured before fragmentation. The binding constant of villin to the barbed end of the actin filament was calculated to be greater than 10(11) M-1. The rate constants of elongation and of depolymerization at each end of an actin filament were measured. The depolymerization rate constant from the barbed end was about 10 times greater under conditions leading to complete depolymerization than under steady-state conditions. We discuss a possible explanation for the finding and its implication for possible regulatory mechanisms.

4-Chloro-7-nitrobenzofurazan↗
PubMed1984

Dietary control of aldolase B and L-type pyruvate kinase mRNAs in rat. Study of translational activity and hybridization with cloned cDNA probes.

Liver L-type pyruvate kinase and aldolase B mRNAs are the two species whose translational activity increases the most after feeding starved rats a high carbohydrate diet (Simon, M. P., Besmond, C., Cottreau, D., Weber, A., Chaumet-Riffaud, P., Dreyfus, J. C., Sala Trépat, J., Marie, J., and Kahn, A. (1984) J. Biol. Chem., in press). We therefore compared the pattern of this induction in three tissues synthesizing these enzymes, e.g. the liver, small intestine, and kidney. Influence of high lipid and protein diets on liver L-type pyruvate kinase and aldolase B mRNAs was also investigated. In the starved rat livers, L-type pyruvate kinase mRNA was practically undetectable. Carbohydrate diet induced an increase of both mRNA concentrations, with a maximum at the 12-18th h; at this time, mRNA concentration was increased about 4-8 times for aldolase B and 40-100 times for L-type pyruvate kinase, translational activities representing about 1% of the total mRNA activity for both enzymes. After the 24th h of carbohydrate diet, mRNA concentrations decreased slightly, then remained in plateau. In animals refed the high carbohydrate diet, starvation as well as high lipid and protein diets provoked a rapid decrease of both mRNA concentrations and translational activities. In the kidney, aldolase B mRNA synthesis was high in starved rats and was only slightly stimulated by carbohydrates (1.5-2.5 times). L-type pyruvate kinase mRNA concentration was increased 6-15-fold after feeding a high carbohydrate diet. In the small intestine, in contrast, the extent of aldolase B mRNA induction by a carbohydrate diet was similar to that in the liver, while L-type pyruvate kinase mRNA concentration was practically similar in starved and refed rats (about 1:10 of the concentration observed in refed rat liver). These results seem to indicate that the mechanisms responsible for carbohydrate induction of L-type pyruvate kinase and aldolase B are different. In addition, dietary control of each enzyme is also different in the various tissues which synthesize them.

Animals↗
PubMed1984

[Toxic shock syndrome. Current knowledge on its clinical aspects, pathogenesis, diagnosis and therapy].

Toxic-shock syndrome caused by toxins of staphylococcus aureus, is characterized by acute onset of high fever, hypotony, diffuse or palmar-plantar exanthem followed by skin desquamation and multisystem involvement. The disease is mostly associated with the use of intravaginal tampons by menstruating women, but has also been observed not with menstruation and may also occur in males. The clinical diagnosis is confirmed by cultural demonstration of staphylococcus aureus in samples of localized infections with this agent. beta-lactamase-resistant antibiotics are the remedy of choice for chemotherapy.

Combined Modality Therapy↗
PubMed1984

Annoyance and irritation by passive smoking.

The acute irritating and annoying effects of smoke have been investigated in field and laboratory studies by examining the concentration of some smoke components in air. In the workplace, 30 to 70% of the indoor carbon monoxide, nitrogen oxide, and particulate concentrations are due to tobacco smoke; 25-40% of the employees are disturbed and/or annoyed by smoke and 25% suffer from eye irritation at work. Subjective eye, nose, and throat irritations and eye blink rate increase with increasing smoke concentration and increasing exposure duration. Irritation is due mainly to the particulate phase of environmental tobacco smoke, whereas the gas phase is, to a large extent, responsible for annoyance. It is concluded that healthy individuals can tolerate an environmental tobacco smoke level that corresponds to a carbon monoxide concentration of 1.5 to 2.0 ppm. Above these limits, countermeasures to protect passive smokers are necessary. In order not to exceed the upper tolerable threshold limit of 2.0 ppm carbon monoxide, it is necessary to have a fresh air supply of 33 m3 per hour per cigarette smoked. Special attention should be paid to groups of people with increased sensitivity to environmental tobacco smoke, e.g., asthmatics, allergic individuals, chronic bronchitis sufferers, and children.

Acrolein↗
PubMed1984

Simplified high performance liquid chromatographic quantitation of antipyrine.

Antipyrine is used as an index of hepatic drug metabolism. The authors devise a simple and rapid high performance liquid chromatography method to quantitate antipyrine in serum with small volume (50 microliters). Minimal sample preparation is needed and the assay is sensitive to concentrations of 0.2 micrograms/ml. Mobile phase consists of 35% methanol in 67 mM phosphate buffer pH 3.5 with antipyrine detected by monitoring the eluate at 225 and 254 nm. Within-run and run-to-run coefficients of variation are less than or equal to 2.8 and 4.6%, respectively. Recoveries from serum average 100.8%. It is concluded that this technique for antipyrine is simple, rapid, and well characterized.

Antipyrine↗
PubMed1984

Isolation and immunological characterization of a glycoprotein from adrenal chromaffin granules.

A glycoprotein (s-GP III) was isolated from the soluble lysate of chromaffin granules by chromatography with immunoaffinity and lectin columns. An identical protein (m-GP III) was shown to be present in the granule membranes. The apparent molecular weight of these glycoproteins as determined by the electrophoresis system of Laemmli (1970) was 43,000 under reducing conditions. In the absence of mercaptoethanol they aggregated to dimers. Antisera were raised against both the soluble and the membrane-bound forms of this glycoprotein. With these antisera GP III was further characterized: Immunoreplicas were obtained after two-dimensional electrophoresis of soluble and membrane-bound proteins of chromaffin granules. GP III was identified as a protein with a rather broad pI (4.6-5.3), indicating microheterogeneity. As shown by subcellular fractionation, m-GP III is specifically confined to chromaffin granules. GP III can therefore be used as a marker for the membranes of these organelles. The soluble form is secreted from adrenal medulla during stimulation with carbamylcholine chloride. An immunologically identical antigen was detected in adeno- and neurohypophysis. The physiological function of GP III is still unknown. It does not demonstrate any of the enzymatic activities so far known to occur in chromaffin granules.

Adrenal Medulla↗