Biomedicine / [publiee pour l'A.A.I.C.I.G.]最新文献

Although it has been known for some time that alcohol affects the hypothalamic-pituitary-adrenal axis, the clinical significance of this disturbance has only recently become recognised. Over the last 5 years, 27 cases of an apparent Cushing's syndrome have been documented, usually resolving within weeks of alcohol withdrawal. Differentiation from the true Cushing's syndrome can be difficult before resolution, which may be prolonged for several months, but an insulin stress test can be useful in their distinction. The syndrome is invariably pituitary dependent but may not be a specific drug effect of ethanol but rather a consequence of the chronic stress of alcoholism.

It was demonstrated in heterozygous alpha 1- and beta-thalassaemia, that the slow rate of red-cell metabolism of vitamin B6, previously shown to be inherited, is regulated by the FMN-dependent pyridoxine (pyridoxamine) phosphate oxidase, as in control subjects. In this study, 60% of the patients with thalassaemia had a low B6 oxidase activity. An inverse correlation with the stimulation of the FAD-dependent glutathione reductase activity by FAD confirmed that red-cell riboflavin status was responsible. The inherited nature and lack of signs of nutritional riboflavin deficiency led to the conclusion that this was the result of a slow rate of red-cell metabolism of riboflavin. Stimulation of glutathione reductase activity by FAD correlated inversely with its basic activity in thalassaemia and control subjects. There was a high incidence of a low activity of this enzyme per red cell in patients with thalassaemia. The possibility that a low activity of glutathione reductase and a slow metabolism of B6 and riboflavin in the red-cell might play a part in the degree of severity of the thalassaemic disease is discussed.

Estrogen receptors measurement was assayed in human mammary tumors as well as corresponding fine needle aspiration biopsies (95 cases). Correlations between these two determinations were highly significant just as correlations between aspiration biopsies of the same tumor. Some factors may disturb the quality of aspiration biopsy results particularly: 1) a low number of tumoral cells expressed by the cell density, 2) ratio: sample weight-cytosol volume lower than 1/17 corresponding to a too grent dilution, 3) a sample weight lower than 20 mg.

Alveolar macrophages (AM) form the first line of defense against aggression in the lungs. The goal of the present study was to evaluate AM phagocytic function in two types of asthmatic patients: allergic asthma (14 patients) and asthma following ingestion of aspirin (6 patients). Macrophages obtained from bronchiolo-alveolar washings were isolated as a result of their adherence to glass and cultured for 24 hours. The results show that AM viability and phagocytosis of zymosan are reduced in the asthmatic patient. Decreased viability in patients sensitive to aspirin may be the result of alveolar eosinophilia, a quasiconstant finding in asthmatics. Although impaired phagocytosis of zymosan may be explained by the presence of surface IgE on AM of the allergic asthma patient, this is not the case for the aspirin sensitive patient.

It is obvious that biomolecules and in particular structural and functional proteins are flexible systems directly involved in the fundamental and still mysterious mechanisms of cellular life. Such a dynamics of proteins at rest and at work is now experimentally accessible and should permit clear understanding of the activity and regulation of biochemical processes.

The ganglioside content and composition in human neuroblastomas was examined. The densitometric pattern corresponding to the thin-layer chromatography of gangliosides showed no major differences compared to normal brain in the GT area, and variable modifications for GM1 and GD3. The most striking and common features resided in the area corresponding to the disialogangliosides for which is was clear that existed a far more complex pattern than normal human brain.

The time course of sterol biosynthesis was compared after two different stimulations in normal human lymphocytes: culture either in the presence of phytohemagglutinin (PHA) or in a lipid-depleted medium (i. e. a condition which produces sterol efflux). Stimulation by PHA gives rise to an acute and rapid response in 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase activity and cholesterol synthesis. The sterol efflux induction produces a slower and milder response and the delayed sterol production consists mainly of lathosterol.

A new chemically well-defined immunomodulator termed Bestatin was examined for its capacity to interfere with the release of factors from PHA pulsed human peripheral lymphoid cells which are mitogenic for T-cells. The presence of Bestatin, at Concentrations of 0.01-100 microgram/ml, during PHA-pulsing significantly enhanced the subsequent release of mitogenic factors. The highest increase, fourfold, was observed using 10 microgram/ml of Bestatin, Treatment of lymphoid cells with Bestatin alone or pretreatment with this compound before PHA pulsing did not significantly change the subsequent release of these lymphokines.

This study involves 3 children ranging from 10 to 13 years and an eight-month-old infant who received Cis-DDP (30-100 mg/m2) every fourth week by means of a short-term infusion (20-35 minutes). Platinum levels in plasma and urine were determined by flameless atomic absorption spectrophotometry. The decrease in total plasma platinum is triphasic, consistent with the distribution expected for a 3 compartment model. In the elimination phase, the half-life values are high and vary between 149 and 541 hours. The total plasma clearances are extremely low and range from 0.027 to 0.187 litre/hour. The urinary excretion of platinum during the first 5 and 7 days respectively, in two children following administration of Cis-DDP results in large platinum concentrations (40-71 mg/litre) in the first urine excreted from each child. The cumulative urinary platinum excretion in the first twelve hours is high i. e. 27.2 to 32.5% of the administered dose but them it does not exceed 50% even after 5 days. These results confirm that after a short-term infusion of Cis-DDP in a single dose, the kidneys are suddenly subjected to platinum in high concentrations. In order to minimize the nephrotoxicity of this platinum complex, while maintaining sufficient plasma levels to ensure its anti-neoplastic activity, we recommend a schedule consisting of fractionated doses.