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Biomedical subjects

M Stefan

Publications and source records attributed to M Stefan.

At least 37 records · Page 2Linked to original sources
PubMed1977

[The determination of surface tension in amniotic fluid as a simple method for the diagnosis of fetal lung maturity (author's transl)].

For the past several years it is possible to determine the maturity of the fetal lung from the amniotic fluid. Towards the end of the pregnancy the content of surface active substances for instance Lecithine, increases in the amniotic fluid. It is therefore possible to determine the maturity of the fetal lung directly by measurements of the surface tension in the amniotic fluid. In 265 patients from 17 to 42 weeks gestation a total of 340 determinations of the surface tension in the amniotic fluid were carried out. A simple commercial interfacial tensiometer was used. The clinical value of the measurements was determined by the occurrance of a respiratory distress syndrome which was objectively evaluated by the so called Hobel Score. The determination of the surface tension for the amniotic fluid is valuable as a screening test prior to the determination of the relatively expensive L/S ration. The test was compared with the Clements Test which is also a screening procedure.

Amniotic Fluid↗
PubMed1976

Dynamic asymmetries in liver tyrosine aminotransferase induction.

Changes in liver tyrosine aminotransferase activity were measured in mice and rats following a whole body X-irradiation in order to ascertain the dose-effect relationship. The response was either (1) linear in case of low pulses (25 rad/min); (2) parabolic, indicating the onset of a saturation process in case of medium pulses (60 rad/min), or (3) biphasic, suggesting the cooperation of at least two regulatory mechanisms following longtime exposure to strong stimuli (100 rad/min).

Adrenalectomy↗
PubMed1975

Effects of 2200-m hypoxia on glucidic metabolism.

Rats exposed for different intervals (1, 3 and 6 hours, the first day, and then 6 hours a day for 9 days) to a 2200-m hypoxia presented metabolic changes demonstrating an anaerobic glucose utilization. Thus, in accordance with other authors, at different depressurization values the liver homogenate had increased lactate and pyruvate concentrations, decreased NAD and NADH2 concentrations and a decreased ATP formation, demonstrating the inefficient glucide metabolization. These modifications were evident in the first hours of depressurization, but did not occur under acclimatization during the 9 days of exposure. The LDH concentration remained practically unchanged, which might be explained by its explained by its excessive presence in relation to the normal exercise solicitation. A urinary hypercompensatory alkalinization was also recorded.

Adenosine Triphosphate↗
PubMed1975

Stress-induced response of mouse liver tyrosine aminotransferase after irradiation.

On X-ray irradiated mice with a total dose of 800 R, the reactivity upon an aggressive agent (chloroform stress) administered at various delays after irradiation was studied. The reactivity of the animals has been emphasized by the hepatic induction of the tyrosine aminotransferase and by the adrenal ascorbic acid depletion. From the 3rd day after irradiation both these parameters showed a marked and irreversible decrease.

Animals↗