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Biomedical subjects

V Schmidt

Publications and source records attributed to V Schmidt.

At least 91 records · Page 5Linked to original sources
PubMed1983

[Enzyme activity of isolated leukocyte populations. I. Cytochemical and zymographic studies of stored blood under various storage conditions].

Heparinized venous blood was stored under sterile conditions at different temperatures (4 C, 20 C, 37 C) for various intervals (0-7 days). After storage the granulocytes and lymphocytes were isolated with routine methods. Naphthol AS-D-chloroacetate esterase as a granulocyte marker and acid alpha-naphthyl acetate esterase as a T-lymphocyte marker were identified on smears of the washed cell suspension. Different enzymes were identified in the cell sediment with electrophoresis. Relatively pure lymphocyte suspensions were obtained within the first 24 h. After this time, however, the percentage of these mononuclear cells declined markedly. The percentage of isolated granulocytes varied slightly; there was a marked predominance of granulocytes (more than 70%) at all intervals investigated during the isolation. Cytochemical analysis of the granulocytes and lymphocytes indicated that the decrease in the percentage of enzyme-positive cells depends in each case on the duration of the storage interval. During the first 24 h, only PGM1 and GOTM could be identified in the lymphocyte suspension with horizontal starch gel electrophoresis. The enzymes PGM1, PGM3, PGI, MDH, GOTM, 6-PGD, ADA could always be identified in the granulocyte suspension; AK, FUCA, MEM could be occasionally identified; and GPT and GLO could never be identified.

Blood Preservation↗
PubMed1983

Synthesis and bacterial metabolism of cis- and trans-2-alkyl analogues of sodium cyclamate.

Sodium cyclamate is an effective artificial sweetner, which has been banned from the U.SD. market because of alleged carcinogenic properties. It appears that cyclohexylamine, liberated from cyclamate as a result of bacterial mtabolism, is the proximate carcinogen. In an effort to elucidate the extent to which analogues of cyclamate would enter into the bacterial metabolic pathway, as well as any stereochemical requirements which might exist, several 2-alkaly analogues of sodium cyclamate were prepared. It was found that trans-N-(2-methylcyclohexyl)sulfamate (trans-2a) and trans-N-(2-ethylcyclohexyl)sulfamate were hydrolyzed by freshly collected fecal suspensions from rats fed cyclamate, but not from control rats, at the same rate as cyclamate itself. trans-N-(2-Isopropylcyclohexyl)sulfamate (trans-2c) was not hydrolyzed at all. Surprisingly, two of the analogous cis compounds (cis-2a and cis-2c, respectively) were hydrolyzed by fecal suspensions from control, as well as from cyclamate-fed, rats. Moreover, cis-2a was hydrolyzed by incubating it in medium only. Thus, it is apparent that stereochemical influences on the chemical properties of these compounds are substantial. These results do not appear to point the way toward a safe, nonmetabolizable sweetening agent.

Animals↗
PubMed1981

Effect of a precooling maneuver on body temperature and exercise performance.

Twelve subjects exercised to exhaustion at an ambient temperature of 18 degrees C on a bicycle ergometer with the load being stepwise increased. On one day, exercise was preceded by a precooling maneuver. In the precooling tests, deep body temperature attained values of about 1 degree C lower than in the control tests. There was no indication of metabolic cold defense reactions being evoked throughout the exercise period. In the precooling tests, heart rate was significantly lower than in the controls, but the mean maximum work rate, peak oxygen uptake (VO2), time to exhaustion, and total work were not reduced, i.e., work rate and VO2 were increased for a given heart rate. In the three subjects with the lowest maximum work rates, total work and exhaustion time and, in two cases, maximum work rate were increased after precooling. The onset of sweating occurred at higher work rates but at lower core, mean skin, and mean body temperature after precooling. However, the accumulated sweat secretion was considerably smaller after precooling, indicating less thermoregulatory effort.

Body Temperature↗
PubMed1979

Monoamine oxidase inhibiting and toxic effects of acetyl-phenylhydrazide on rat liver in vivo.

For induction of reticulocytosis, rats had been routinely treated with the haemolytic agent, acetyl-phenylhydrazide (APH), and monoamine oxidase (MAO) activity was determined in reticulocytes. Since hydrazines are known to be irreversible inhibitors of MAO, the MAO inhibiting potency of APH was assessed in vitro and in vivo. Only in vivo, an apparently organ-selective MAO inhibition was observed in rat liver; in addition, the rate of recovery of MAO activity in vivo after inhibition with APH was considerably prolonged, indicating a toxic effect of APH on this organ. However, clinical-chemical and pathohistological parameters did not reveal any signs of an overall liver parenchymal cell damage. Hence, a more specific interference of APH with mitochondrial enzyme synthesis must be postulated.

Animals↗