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Biomedical subjects

F Stastný

Publications and source records attributed to F Stastný.

At least 55 records · Page 3Linked to original sources
PubMed1979

Regional distribution of membrane-bound gamma-glutamyl transpeptidase activity in mouse brain. Comparison with rabbit brain.

Activity of membrane-bound gamma-glutamyl transpeptidase (gamma-GTP) was examined in various regions of mouse brain, in capillaries of the cerebral cortex and in telencephalic choroid plexuses. The level of activity in the capillaries was double and that of the choroid plexus nine times that of the gamma-GTP activity found in the brain, septum, hippocampus, hypothalamus, thalamus, cerebellum, frontal cortex, pons, medulla oblongata, and amygdala. Histochemically the gamma-GTP activity was demonstrated in the surface membranes of choroidal cells and in the endothelium of small capillaries. The activities of gamma-GTP of cerebral cortex, choroid plexus, and capillaries from rabbit were 5--17 times greater than those from corresponding areas of mouse brain. While 30 mM methionine stimulated (in vitro) the enzyme from mouse brain, no such effect was observed with the enzyme activity from rabbit brain. The gamma-GTP activity from the capillaries of cerebral cortex of both mouse and rabbit was not affected by the presence of methionine. These findings suggest existence of differences in the specificity of gamma-GTP activity in these two species.

Amygdala↗
PubMed1979

Effect of altitude hypoxia on ATPase activity in the brain of rats of different ages.

In experiments on 5-day-old and adult rats of both sexes, the authors investigated Na+--K+-stimulated and Mg2+-dependent ATPase activity in the cerebral cortex, subcortical formations and the medulla oblongata. They studied the effect of 20 min acute altitude hypoxia corresponding to either 7,000 or 9,000 m, in a thermostable chamber (30 degrees C). ATPase activity was found to increase during ontogenesis -- this being the greatest in cortical tissue and the least in the medulla oblongata. Hypoxia corresponding to 7,000 m altitude significantly depressed total ATPase activity in 5-day-old rats, but significantly stimulated it in adult animals. Changes in Na+--K+-stimulated ATPase activity played the major role in these changes. Hypoxia corresponding to 9,000 m altitude likewise depressed total ATPase activity in 5-day-old rats and to practically the same extent as moderate hypoxia (7,000 m). In adult rats, marked hypoxia (9,000 m) significantly reduced only Mg2+-dependent ATPase activity. Mg2+ activity rose during ontogenesis to a lesser degree than Na+--K+-stimulated ATPase and the reciprocal ratio of these ATPase and the reciprocal ratio of these ATPase activities, in the given parts of the brain, fell progressively in adult animals to values close to 1.

Adenosine Triphosphatases↗
PubMed1979

Effect of adrenaline and triamcinolone on cytochrome oxidase activity in the brain and liver of young and adult rats.

The effect of adrenaline (0.15 i.p./kg b.w.) and of the synthetic glucocorticoid triamcinolone (40 mg i.p./kg b.w.) on cytochrome oxidase activity, the terminal enzyme of the cytochrome system, was studied in homogenates of the cerebral cortex, subcortical formations (including the basal ganglia, the thalamus and the hypothalamus), the medulla oblongata and the liver of 5-day-old and adult rats. Activity in the above mentioned homogenates was measured polarographically 15 and 30 min after administering adrenaline or 48 h after administering triamcinolone. Fifteen minutes after its injection, adrenaline caused a statistically significant drop in cytochrome oxidase activity in the cerebral cortex, subcortical formations and liver of 5-day-old rats. The decrease still persisted 30 min after administration of the hormone, but was intensified only in the liver. In adult rats, on the other hand, a significant increase in activity was observed in the cerebral cortex and liver after adrenaline. Triamcinolone had no effect on cytochrome oxidase activity in any of the given parts of the brain in either young or adult rats. It significantly stimulated cytochrome oxidase activity in the liver of 5-day-old rats, but severely inhibited it in the liver of adult rats.

Age Factors↗
PubMed1978

Influence of age and short-term starvation on the ATPase activity in the developing rat brain.

Na+-K+-stimulated and Mg++-dependent ATPase activities were investigated in the developing cerebral cortex, subcortical structures, and medulla oblongata of rats as was the effect of 24-hr lasting starvation and thirst on those enzyme activities. We found (a) a developmental increase of these ATPase activities in the developing rat brain with the maximum in the cerebral cortex and with the minimum in the medulla oblongata; (b) a decrease of the ratio of these enzyme activities, which was near unity in adult animals; (c) an increase of ATPase activities in the cerebral cortex and subcortical formations of young rats under starvation conditions followed by a decrease of the Mg++/Na+-K+-ATPase activity ratios in these structures; and (d) a decrease of these activities, especially in the cerebral cortex, and an increase of the activity ratios in adult animals under starvation conditions.

Age Factors↗
PubMed1977

Experimental allergic encephalomyelitis. Water, sodium and potassium concentration in spinal cord and hemispheres and their changes after dexamethasone treatment.

Water content, Na+, K+ and Cl- concentration were measured in rats with experimentally produced allergic encephalomyelitis. Increase of water content by 10%, accumulation of Na+ by 13%, of Cl- by 20% and decrease of K+ by 10% was observed in the spinal cord, but no substantial changes were found in the brain tissue. The hydration of spinal cord is accompanied by perivascular infiltrates. Dexamethasone, administered from day 5, after injecting sensitising encephalitogenic basic protein, effects normal levels of water content and Na+, K+ and Cl- concentration.

Animals↗
PubMed1976

Quantitative development of choroid plexuses in chick embryo cerebral ventricles.

Quantitative development of choroid plexuses in cerebral ventricles of chick embryos was investigated by means of the planary projection of the choroid plexuses from the time the plexuses reached a consistent flattened structure. Choroid plexuses in the lateral cerbral ventricles were studied from day 6, the plexus in the third cerebral ventricle from day 8, and the plexus in the fourth cerebral ventricle from day 11 of incubation. Regardless of the microscopic origin of these choroid plexuses, their development reached a growth maximum on day 15 of incubation, after which there was a slight regression. The regression was gradual in the plexus of the third cerebral ventricle but a transient enlargement of plexuses in the laternal and in the fourth cerebral ventricle was observed between days 18 and 19. The enlargement of choroid plexuses in the lateral cerebral ventricles was caused by a flattening of the villi, whereas that of the plexus in the fourth cerebral ventricle was caused by thinning and yawning of the villi. The area of choroid plexuses in the lateral cerebral ventricles was six or seven times larger than the sum of the areas of the remaining choroid plexuses.

Animals↗
PubMed1976

Effect of hydrocortisone on the growth of choroid plexus and composition of cerebrospinal fluid in the developing chick embryo.

The effect of hydrocortisone on the telencephalic choroid plexus and on the osmolarity and ionic compositon of CSF was studied 48 hours after its administration onto the chorio-allantoic membrane of chick embryos on days 11 and 13 (20 mug per egg) or on day 17 (40 mug per egg). Hydrocortisone significantly reduced the choroid plexus area on days 13 and 15 but was ineffective on day 19. The topical analysis of these choroid plexuses, influenced by the steroid, pointed to a decrease of the growth activity in those parts whose proliferation was intensive. The transient population of villi in the apical part of these plexuses was the most sensitive. Those parts, being morphogenetically inactive or whose morphogenetic changes were not caused by the cellular proliferstion, were not affected significantly. The osmolarity of CSF increased significantly during the investigated period simultaneously with an increase in the sodium and chloride concentration while the concentrations of potassium did not change significantly. Hydrocortisone evoked a precocious increase in the osmolarity of CSF on days 13 and 15. Contemporarily, the potassium concentration in CSF was elevated while the steroid failed to change the sodium and chloride concentrations.

Animals↗