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Biomedical subjects

M Praslicka

Publications and source records attributed to M Praslicka.

At least 19 recordsLinked to original sources

[Comparative study on myocardial damage in irradiated for a long time and nonirradiated rats after administration of FCOL].

The trials were made to assess the effect of FCOL (9-alpha-fluorocortisol + Na2HPO4) and the effect of K and Mg asparaginates and their mixtures on the modifications of Ca2+, Na+, and K+ ions and of the K/Na ratio in the myocardium of rats not irradiated or submitted to permanent whole-body irradiation (gamma irradiation with 0.57 Gy per day during 25 days, total accumulated dose 14.25 Gy; the trials were performed 25 days after the irradiation). The totality of reversible and irreversible functional modifications of the myocardium, expressed by the quantitative assessment of the K/Na ratio and the concentration of Ca2+ ions, was evaluated in order to determine the cardiotoxicity or cardioprotection. It was demonstrated that irradiation alone causes a slight irreversible modification in the myocardium which is not found in non-irradiated rats. FCOL itself increases the rate of Ca2+ and Na+ ions in irradiated and non-irradiated rats, but does not influence the quantity of K+ ions. Severe irreversible myocardial damages are caused by FCOL, but these damages are considerably lower in irradiated rats. Neither in irradiated nor in non-irradiated rats, the isomers of Mg asparaginate show any protective action against the cardiotoxic effect of FCOL. The isomers of K asparaginate, also combined with Mg asparaginates, as well as the preparation Inzolen exert a demonstrable protective effect against myocardial ion modifications following to application of FCOL. The protection is more efficient in irradiated rats.

Animals↗

Circadian changes of gluconeogenic enzymes in irradiated rats.

The authors studied the effect of whole body irradiation at different times of day on the circadian rhythms of gluconeogenic enzymes. They found that: 1. liver and kidney enzyme activities were highest in the light part of the day and lowest in the middle of the dark part; 2. 12-h circadian rhythm of glucose-6-phosphatase and fructose-1, 6-bisphosphatase activity in the liver and the renal cortex followed a similar course; 3. a lethal whole body dose of 14.4 Gy X-rays did not affect the circadian oscillation curves of the given enzymes, with the exception of fructose-1, 6-bisphosphatase in the liver of irradiated rats, where the rhythm was lost.

Animals↗

[Recovery of hematopoiesis in mice following a continuous irradiation with a dose rate of 0.957 Gy/d and a total accumulated dose of 19.14 Gy. I. Bone marrow, spleen and thymus gland].

This paper deals with the evaluation of histological changes in the bone marrow, spleen and thymus of mice after continuous irradiation with a dose rate of 0.957 Gy/day and a total accumulated dose of 19.14 Gy. Erythropoiesis in the spleen could be recovered quickly, significantly exceeding the spleen erythropoiesis of the controls on the seventh post-irradiation day. Myelopoiesis in the bone marrow could be recovered until the 21st day and erythropoiesis until the 28th day after the end of irradiation. Lymphopoiesis in the thymus could be recovered on the 28th day approximately and in the spleen roughly on the 60th day after the end of irradiation.

Animals↗

Gluconeogenesis in lethally X-irradiated rats.

The in vivo incorporation of U-14C-alanine into blood glucose and liver glycogen was measured in rats irradiated with a single whole body lethal dose of X-rays. Changes in gluconeogenic enzyme activities were studied in the liver. Increased incorporation of 14C-alanine into blood glucose and liver glycogen were found after irradiation. Liver phosphoenolpyruvate carboxykinase and glycogenic activity underwent almost parallel changes and were significantly elevated from the 6th to the 48th hour, with resultant accumulation of glycogen. Glucose-6-phosphatase activity was depressed and there was a negative correlation between it and the liver glycogen concentration. Maximum fructose-1,6-diphosphatase activity was found at 48 hours. The results show that glycogen accumulation in the liver and the raised blood glucose level in X-irradiated rats are based on raised gluconeogenesis.

Alanine↗

[The effect of graduated radiation doses on the follicular apparatus of the ovaries and the adenohypophysis in sheep].

Gradually increased radiation doses were applied directly to the ovaries of laparotomized ewes. The effect of these doses was studied as exerted on the qualitative and quantitative changes in the follicular apparatus of the ovaries and adenohypophysis of ewes in anoestrus and upon the recovery processes later on after irradiation. The ovaries irradiated with the dose of 4.79 Gy were found to be heavier when examined after some time from irradiation. The 10th and 30th day from irradiation the number of tertiary follicles decreased, the 100th day from irradiation their number increased to a four-fold level, as compared with the 10th day. Adenohypophysis showed a gradual growth of the number of PAS-positive cells. After the irradiation of ovaries with the dose of 9.57 Gy the ovaries showed the lowest rate of damage on the 10th day from irradiation; the 30th and 100th day from irradiation all the present tertiary follicles were in the state of atresia. In comparison with the control group, the amount of gonadotropic cells of adenohypophysis gradually increased, recovering from a rapid drop after irradiation. When the ovaries were irradiated with the dose of 19.14 Gy, all the tertiary follicles were in the state of atresia and the number of PAS-positive cells of adenohypophysis was lower in comparison with the control group.

Anestrus↗

Oscillations of serum and tissue lipids in rats X-irradiated at different times of day.

Young male Wistar rats (mean body mass 200 g) adapted to a 12: 12 h light: dark regimen (7 a.m.--7 p.m., 7 p.m.--7 a.m.) were X-irradiated at 3-h intervals during one day with doses of 2.39 or 14.25 Gy and were killed 48 or 24 h afterwards. Non-esterified fatty acids were determined in their serum and white and brown adipose tissue, and triacylglycerols, phospholipids and total cholesterol in their serum and liver. The reaction of serum and tissue lipids during the day varied after both non-lethal and lethal irradiation. After non-lethal exposure, most of the curves, as regards their course, the presence of rhythm and their oscillation properties, concurred with the lipid indicator curves in the control series and indicated that the organism's response is dependent on the time of day. Circadian variation of serum and adipose tissue non-esterified fatty acid levels, the liver triacylglycerol concentration and the adrenal cholesterol concentration in lethally irradiated animals showed no significant dependence on the time of application of the stimulus. An analysis of circadian variation of the effectiveness of a stimulus facilitates an understanding of the organism's reactivity better than a single examination in the morning.

Adipose Tissue↗

The effect of artificial gravity on plasma and tissue lipids in rats: the Cosmos 936 experiment.

Plasma and tissue lipids in male SPF Wistar rats flown for 18.5 days aboard the Cosmos 936 biosatellite were analyzed. One group of rats was subjected to artificial gravity by use of a centrifuge during the flight. An experiment simulating known space flight factors other than weightlessness was done on Earth. An increase of total cholesterol in plasma, of nonesterified fatty acids in plasma and brown adipose tissue, of triacylglycerols in plasma, liver, thymus and bone marrow was noted several hours after biosatellite landing. Smaller changes were observed in the terrestrial control experiment. With the exception of triacylglycerol accumulation in bone marrow, these increases disappeared 25 days after biosatellite landing. Exposing the rats aboard the biosatellite to artificial gravity was beneficial in the sense that such exposure inhibited the phospholipid and triacylglycerol increase in plasma and inhibited the increase of triacylglycerol in liver and especially in bone marrow.

Adipose Tissue, Brown↗