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Biomedical subjects

W Braun

Publications and source records attributed to W Braun.

At least 235 records · Page 13Linked to original sources
PubMed1980

[Basic problems of educational gerontology (author's transl)].

The author attempts an integration of gerontology into an educational concept by analysing the anthropological aspects of ageing and the effects of social change brought about by the industrialisation. Since Descartes postulated a dualisting model of man is well-being depends on the well-being of the body. Thus old age and ageing must be seen as an individual as well as a social problem in so far as the "I" may loose its integrative power; social, because having to live in homogeneous age groups of modern society (rather than in heterogenous age groups of older days) may result in a loss of meaning. It's at this point that the aging individual needs help.

Aged↗
PubMed1979

Acute toxicity of methyl fluorosulfonate (Magic Methyl).

Methyl fluorosulfonate (Magic Methyl), an active methylating agent used by research chemists, was studied for acute oral toxicity, acute inhalation toxicity, ocular irritation, and dermal irritation. This compound is very hazardous and may have been responsible for at least one human death. The results of these studies confirmed that Magic Methyl is markedly toxic by all routes studied and particularly by the inhalation route since the LC50 value for rats was found to be between 5 and 6 ppm.

Administration, Oral↗
PubMed1978

The effect of fatty acids on the regulation of pyruvate dehydrogenase in perfused rat liver.

The effect of fatty acids on the rate of pyruvate decarboxylation was studied in perfused livers from fed rats. The production of 14CO2 from infused [1-14C]pyruvate was employed as a monitor of the flux through the pyruvate dehydrogenase reaction. A correction for other decarboxylation reactions was made using kinetic analyses. Fatty acid (octanoate or oleate) infusion caused a stimulation of pyruvate decarboxylation at pyruvate concentrations in the perfusate below 1 mM (up to 3-fold at 0.05 mM pyruvate) but decreased the rate to one-third of control rates at pyruvate concentrations near 5 mM. These effects were half-maximal at fatty acid concentrations below 0.1 mM. Infusion of 3-hydroxybutyrate also caused a marked stimulation of pyruvate decarboxylation at low pyruvate concentrations. The data suggest that the mechanism by which fatty acids stimulate the flux through the pyruvate dehydrogenase reaction in perfused liver at low (limiting) pyruvate concentrations involves an acceleration of pyruvate transport into the mitochondrial compartment due to an exchange with acetoacetate. Furthermore, it is proposed that a relationship exists between ketogenesis and the regulation of pyruvate oxidation at pyruvate concentrations approximating conditions in vivo.

Acetoacetates↗
PubMed1978

The effect of two different renal preservation methods on canine renal allograft survival.

Preservation of human cadaver kidneys for transplantation has been achieved primarily by two methods, hypothermic pulsatile perfusion with cryoprecipitated plasma and cold storage with an electrolyte solution. It has been suggested that pulsatile perfusion results in an increased antigenicity of the transplanted kidney. To investigate the possibility that pulsatile perfusion causes changes which may accelerate allograft rejection, machine preservation was compared with simple cold storage. The kidneys were preserved by either one of the two methods for 6 or 24 hours followed by allotransplantation in nephrectomised dogs. No immunosuppressive drugs were given. Kidneys which were allografted without undergoing any preservation (0 hrs) had a mean survival time of 10.4 +/- 1.7 days (n =5). Kidneys preserved by machine perfusion for 6 and 24 hours survival for 9.6 +/- 1.4 (n = 5) and 10.9 +/- 1.3 (n =9) days respectively. The mean survival time for simple cold storage for 6 and 24 hours was 9.3 +/- 1.3 (n =7) and 12.0 +/- 1.9 (n =6) days. Our findings suggest that in kidneys exposed to minimal warm ischaemia there is no significant difference between the two methods of preservation on renal allograft survival for the time intervals tested.

Animals↗
PubMed1978

Studies on the time and localization of the puberal desensitization to oestrogen in female rats.

Immature and postpuberal female rats were ovariectomized at 20 or 27 days of age or on the day of the first vaginal oestrus and chronically implanted with oestradiol benzoate (OB) and cholesterol at the ratios of 1 : 60, 1 : 120 or 1 : 240 on the day following castration. Autopsy was performed on day 6 after implantation and the plasma LH concentration determined by radioimmunoassay. Whereas 1 : 60 and 1 : 120 implants of OB and cholesterol placed into the hypothalamic ventromedial-arcuate region depressed the castration-induced elevation of the LH level before and after puberty, the 1 : 240 mixture was effective only in immature rats, but not after vaginal opening and the first ovulation had occurred. A similar trend was recorded after implantation of OB into the cortical amygdaloid nucleus (CAN). However, the oestrogen dose had to be doubled to get comparable results. Bilateral lesioning of the CAN or deefferentation of the mediocortical amygdala by transection of the stria terminalis did not distinctively influence the LH-suppressing effect of daily s.c. injections of 0.1 or 0.05 microgram OB/100 g b. w. in prepuberal rats. The findings demonstrate a sudden change in the hypothalamic threshold to the gonadotrophin-inhibiting effect of oestrogen over a narrow range of time near the onset of puberty. They furthermore suggest that the mediocortical amygdala is not involved in possible extra-hypothalamic control of the puberal desensitization process.

Animals↗