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Biomedical subjects

J Mourek

Publications and source records attributed to J Mourek.

At least 91 records · Page 5Linked to original sources
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↗
PubMed1976

Influence of age and starvation on pO2, pCO2 and haematocrit values in the rat.

The author determined the effect of acute starvation on the arterial pO2 and pCO2 value (analysed on a micro-Astrup apparatus) in rats of different ages; in infant rats, this was done by separating them from the female and the nest for 24 hours. Arterial blood was obtained by incising the tail artery. It was found that the pO2 value in rat arterial blood rose signficantly during ontogenesis. At 10 and 14 days the mean pO2 value was 68 torr, while at 25 days and in adult rats it was 92-95 torr. No marked changes were found in CO2 during ontogenesis (the mild drop was not statistically significant). In 10- and 14-day-old rats, 24 hours' starvation caused a significant decrease in pO2. In older rats, deprivation of food and water did not significantly affect the pO2; in the arterial blood. The arterial blood pCO2 was not influenced by starvation. The development of the haematocrit values in mixed blood (obtained by decapitation) during ontogenesis was in agreement with findings in the literature, i.e. a drors' complete starvation produced no change in the haematocrit values in 5- and 10-day-old rats, but a marked increase was recorded in older rats.

Aging↗
PubMed1976

Influence of starvation on lactic dehydrogenase activity in the serum and brain of rats of different ages.

The authors investigated the effect of 24 hours' acute deprivation of food and liquids on lactic dehydrogenase (LDH) activity in the serum, cerebral cortex, subcortical formations and medulla oblongata of 6- and 14-day-old and adult rats. Young rats were starved by separating half of a standard litter from the female for 24 hours. LDH activity was determined by means of Sevac-test-LDH (Imuna, Czechoslovakia) and was expressed in I.U./litre serum or 1 kg tissue wet weight. The samples were prepared at 0 degrees C. LDH activity in the various parts of the CNS was measured in the supernatant of homogenates of the above tissues and the greatest possible destruction of the tissues was ensured by freezing and thawing the homogenates prior to centrifugation. The specimens were incubated at 37 degrees C. Extinction was measured on a SPECOL (G.D.R.) apparatus at 505 nm wavelength. We found that 24 hours' deprivation of food and liquids, together with sensory deprivation in the youngest age groups, significantly reduced LDH activity in both the serum and the cerebral cortex of 6-day-old rats. In adult rats, starvation and thirst raised LDH activity, but the only statistically significant increase was in the medulla oblongata. Under our experimental conditions, LDH activity rose during development by 274% in the cerebral cortex, by 233% in subcortical formations and by 173% in the medulla oblongata. The differences betwen these developmental trends are statistically significant.

Age Factors↗
PubMed1976

Influence of cerebrolysin(r) on the resistance of rats to anoxia.

Single injections of Cerebrolysin(R) did not affect the resistance of rats to anoxia, irrespective of age. Cerebrolysin(R) significantly raised the resistance of the young of females injected ten times i.p. with the same dose during pregnancy. The repeated (5-fold) administration of Cerebrolysin(R) significantly raised the resistance of 35-day-old rats to anoxia and, in high concentrations, it also increased the resistance of adult rats. The effect of Cerebrolysin(R) is correlated to the proportion of amino acids, aligopeptides and the nucleotides they contain. The mere administration of a mixture of amino acids or of some other hydrolysate (Testolysin) was ineffective in this respect.

Amino Acids↗
PubMed1975

Enzymatic activities in mitochondria isolated from the rat brain during development.

In an attempt to discern whether mitochondrial changes during ontogeny are due to increases in number of mitochondria or to increases in number plus changes in their organization, we investigated the enzymatic markers of the inner and outer membranes of mitochondria from cerebral cortex and subcortical material in young and adult rats. We conclude from the data gathered that significant changes do occur in mitochondrial organization, that gradual maturation occurs in the inner membrane during development, especially in the cerebral cortex and considerably less so in the subcortical structures. We found no such changes in the sturucture of the outer membrane during the periods of development examined.

Animals↗