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M Praslicka

Publications and source records attributed to M Praslicka.

At least 37 records · Page 2Linked to original sources
PubMed1981

Changes of deoxyribonucleoprotein in the spleen, thymus and liver of rats exposed to weightlessness and artificial gravity aboard the Cosmos biosatellites.

Changes of deoxyribonucleoprotein in the spleen, thymus and liver of rats exposed to weightlessness or artificial gravity on board biosatellites Cosmos 782 and Cosmos 936 after 20 days of flight were investigated. The level of polydeoxyribonucleotides in the spleen and thymus of rats exposed during the flight to weightlessness increased 4-11 hours after landing, suggesting breakdown of a part of the deoxyribonucleoprotein present. The use of artificial gravity prevented this breakdown in the thymus but not in the spleen. The breakdown was accompanied in the majority of cases by a decrease in the deoxyribonucleoprotein content. We believe the breakdown of deoxyribonucleoprotein is due to a nonspecific stress reaction to the change from the weightless state to that of terrestrial gravity during landing. The polydeoxyribonucleotide level and amount of deoxyribonucleoprotein in the majority of cases returned to normal values during the 25 days of readaptation. No substantial change of deoxyribonucleoprotein was found in the liver. The different findings in the three organs are due to the fact that breakdown of deoxyribonucleoprotein takes place in sensitive cells underlying pycnosis. These cells are found in the spleen and thymus, but not in the liver.

Animals↗
PubMed1981

Changes in rat liver and adipose tissue lipogenesis in the course of continuous gamma radiation.

Lipogenesis in liver of continuously irradiated rats (dose rate of 0.57 Gy per day for up to 25 or 30 days) was increased, in comparison with control animals, between 7 and 30 days. In the liver of fed rats it was approximately five times higher than animals fasted for 16 hours before sacrifice. Lipogenesis in adipose tissue was decreased on the third day of irradiation and its value was higher than in controls between 7 and 25 days. Glyceride glycerol synthesis in irradiated rats was increased compared with controls on the first, seventh and between 21 and 25 days of continuous irradiation. We suggest that the increase in lipogenesis in the liver of continuously irradiated rats is an important factor in lipid metabolism disorders caused by the continuous irradiation.

Adipose Tissue↗
PubMed1981

[Ultrastructure of cells of rat lymphatic organs during continuous irradiation].

Changes in the ultrastructures of lymphatic organs of rats observed from the 2nd to 22nd day following continuous irradiation with gamma rays at a daily dose of 115 mGy (exposition: 12 R/day) are described. The maximum of destructive changes in lymphocytes was observed on the 11th to the 14th day of irradiation. A gradual balance between dystrophic and regenerative processes was achieved on the 18th day. In this connection to correlation could be determined between the ultrastructural changes described and the fluctuations of lymphocyte numbers in the lymphatic organs and peripheral blood during continuous irradiation.

Animals↗
PubMed1981

Character of changes in the serum proteins of continuously irradiated rats.

Using quantitative two-dimensional immunoelectrophoresis, the authors studied, at various intervals, changes in the serum prealbumin, albumin, A1-globulin A1-macroglobulin (A1M), haptoglobin, haemopexin, transferrin, immunoglobulin G (IgG) and C3 component of complement in rats irradiated continuously with daily input doses of 957 mGy, 1,914 mGy and 3,828 mGy up to the lethal dose. During irradiation with these inputs, the prealbumin, albumin, A1-globulin, A1M, transferrin, IgG and C3 levels fell while the serum haptoglobin and haemopexin concentration rose.

Animals↗
PubMed1981

Effect of dexamethasone on pituitary-adrenocortical response to acute irradiation stress in rats.

After the irradiation with a lethal dose of 387 mC kg-1 (1500 R) an increase of plasma and adrenal corticosterone concentration was found in male rats (about 250 g body weight) during first 24 h as compared to sham-irradiated animals, the maximum increase being observed at 60 min after irradiation. A second period of corticosterone increase was found at 48 and 72 h. At the same time the adrenal weight increased and severe lesions of gastrointestinal tract were found. In a second experiment dexamethasone (50 mg kg-1) was injected 3 h before irradiation and this prevented the increase of plasma and adrenal corticosterone level at 60 min after irradiation. It was suggested that the degradation of corticosterone might be slowed down during the first period after irradiation, while at the same time the feed-back regulatory mechanism of ACTH release from the pituitary apparently remained intact. The second period of corticosterone increase was apparently due to severe gastrointestinal lesions.

Adrenal Cortex↗
PubMed1981

Metabolic changes after non-lethal x-irradiation of rats. I. Carbohydrates, hormones.

Male rats of the Wistar strain were fasted overnight prior to exposure to single total-body X-ray dose of 2.39 Gy (250 R). Irradiated and sham-irradiated rats were pair-fed for 5 days, in the next period they were fed ad libitum. The levels of corticosterone and immunoreactive insulin in serum, glucose in blood, glycogen in liver, heart and skeletal muscle were determined 1 and 6 h, 1, 2, 3, 7, 14, 28, and 38 days after irradiation and sham-irradiation. Irradiation of rats resulted, at one hour, in a decrease and, at two days, in an icrease in level of blood glucose. A marked increase in liver glycogen persisted from 6 h to 21 days after irradiation. The level of glycogen in the skeletal muscle was reduced at 6 h and increased on days 3 and 14. Heart muscle glycogen declined within the first 24 h and rose at 14 days after exposure. The kinetics of changes in the heart and skeletal muscle glycogen following non-lethal irradiation was similar and indicated an overlap of changes produced by fasting with those brought about by irradiation, particularly during the first week. Corticosterone in serum was markedly increased in rats at 24 and 72 h after irradiation compared to pair-fed controls. The serum insulin concentration did not change after irradiation, except for a single increase on day 21. Irradiation with non-lethal doses produced changes in the parameters of the carbohydrate metabolism studied, except for serum insulin, which reflected the changes in the nutrition regimen upon pair-feeding rather than the effect of ionizing irradiation.

Animals↗
PubMed1981

Recovery of hematopoiesis in bone marrow of mice after continuous irradiation with dose rate 4.8 Gy/day.

In this paper the morphological changes in mouse bone marrow till day 60 after the termination of continuous irradiation with the dose rate 4.8 Gy/day (480 rad/day) and the total accumulated doses 9.6 Gy (960 rad) and 19.2 Gy (1920 rad) are evaluated. Many mononuclear cells of the morphologically lymphoid type appear in the bone marrow on day 9 of the recovery and later on extensive granulopoiesis recovery occurs reaching the control level, as early as on day 21--28 after the irradiation. The recovery of erythropoiesis and megakaryocytopoiesis proceeds more slowly and their total recovery occurs within the period of 28--60 days after the irradiation. The total accumulated dose 19.2 Gy (1920 rad) causes irreversible damage in the bone marrow and the death of all experimental animals occurs within 11 days after irradiation.

Animals↗
PubMed1981

Metabolic changes after non-lethal x-irradiation of rats. II. Serum and tissue lipids.

Male rats of the Wistar strain were subjected to whole-body X-irradiation with 2.39 Gy (250 R) and after irradiation they were pair-fed with the sham-irradiated control group. One, 6 and 24 h, 2, 3, 7, 14, 21, 28, and 38 days after exposure the animals were sacrificed and examined for serum and some tissue lipids. In the first hours an increase in lipolysis in the white adipose tissue and accumulation of NEFA and TG in the liver predominated; PL level increased in serum and liver and decreased in bone marrow and thymus. The later phase was characterized by hypertriacylglycerolaemia and a transient hypercholesterolaemia; accumulation of TG in bone marrow was the most important change, however. Changes in the lipid composition of the serum and tissues, except for an increase in TG level in thymus, returned to normal levels at the end of the observation period. Pair-feeding provided an equivalent nutritional situation in irradiated and sham-irradiated animals and thus eliminated the non-specific changes caused by different levels of food intake in both groups of animals, especially in the initial period. A sufficiently long observation period is necessary for estimating the kinetics of metabolic changes in rats exposed to non-lethal doses of X-irradiation.

Adipose Tissue↗
PubMed1980

[Recovery of erythrocytes, leukocytes and thrombocytes after the termination of continuous radiation].

Mice were irradiated continually by a Co60 source with a daily dose of 478.5 mGy (50 R), 957.0 mGy (100 R), and 4785.0 mGy (500 R) up to a total dose of 9570.0 mGy (1,000 R). The restoration of the erythrocyte, leukocyte and thrombocyte numbers in the peripheral blood was observed at different times from 0 to 60 days after finishing irradiation. From all examined cell elements the earliest time of restoration could be observed in thrombocytes, regeneration of erythrocytes and granulocytes followed some time later. Their reparation was completed until the 28th day after finishing irradiation. The longest diminution was found in the number of lymphocytes even on the 60th day remained significantly lower with a dose of 4785 mGy than in control animals.

Animals↗
PubMed1980

Changes in lipoprotein lipase activity in the adipose tissue, heart and liver of continuously irradiated rats.

Adult male Wistar rats were continuously irradiated for 30 days on an experimental field from a 60Co source or radiation. Lipoprotein lipase activity was determined in their adipose tissue, heart and liver at intervals of 1, 3, 7, 14, 21 and 30 days from the beginning of irradiation and triacylglycerol, total cholesterol, phospholipid and non-esterified fatty acid concentrations were determined in their serum. Throughout the whole of the study, lipoprotein lipase activity was lower in the adipose tissue and higher in the heart of irradiated rats than in the controls. In the liver it was low 3 days from the onset of irradiation; at the other intervals it was variable and differed only non-significantly from the controls. Serum lipid concentrations were raised in irradiated rats--triacylglycerol from the 7th day, phospholipids from the 14th day and non-esterified fatty acids throughout the whole period of irradiation. In keeping with the high triacylglycerol values in the serum of irradiated rats, lipoprotein lipase activity in their adipose tissue was low.

Adipose Tissue↗
PubMed1980

Lipid mobilization and lipolysis in adipose tissue of single X-irradiated rats.

Changes in both the concentration of non-esterified fatty acids in serum and white (epididymal) adipose tissue, serum glycerol, and basal and L-noradrenaline-stimulated release of NEFA and glycerol from white adipose tissue in vitro were monitored 1, 6, 24, 48 and 72 h after a single whole-body irradiation of rats with a lethal X-ray dose of 14.35 Gy (1 500R). The NEFA concentration in serum and white adipose tissue was higher 1 h after irradiation as compared with that of sham-irradiated (control) animals; the free glycerol concentration in serum of the irradiated rats was lower than that of control rats. Basal release of NEFA was higher 1 h after irradiation, and lower 6 and 72 h after irradiation; the simulated release of NEFA did not change significantly. Basal and stimulated release of glycerol from the adipose tissue of irradiated rats was higher 6 h after irradiation. The relation between the changes in lipolysis and lipid mobilization and the changes in serum and tissue lipids in the irradiated organisms are discussed.

Adipose Tissue↗
PubMed1980

Changes in lipolysis in rat adipose tissue during continuous irradiation.

Changes in lipolysis was monitored by measuring the release of non-esterified fatty acids and glycerol under basal conditions and after stimulation with L-noradrenaline in rat adipose tissue in the course of continuous irradiation with daily gamma exposure doses of 0.57 Gy (60R) for 50 days. As compared with the control animals, lipolysis in the irradiated rats was lower on days 3-14, and higher on day 21-25-32 and at the end of the screening period (day 50) of continuous irradiation. The changes in lipolysis in the course of irradiation reflected individual stages of the general adaptation syndrome (Selye 1950). Many changes were modified by the effect of non-specific factors due to the experimental field and the starvation prior to the analysis. Changes in lipolysis were connected with changes in the mobilization of fatty acids and the concentrations of NEFA in white adipose tissue with changes in serum lipids predominantly in the period of 21-25 days of continuous irradiation.

Adipose Tissue↗