Influence of a single gamma-irradiation on rat microflora.

Changes in leukocyte counts and in the gut microflora of laboratory rats irradiated with single whole-body dose of gamma rays (5.0 Gy) were determined. The number of leukocytes was lower especially 1 and 2 weeks after irradiation. A significant decrease in lymphocytes was observed 1 week and in monocytes 1 and 2 weeks after irradiation. In parallel with these changes, an increase in common microflora was observed; some microorganisms, which normally are not present in duodenum, liver and mouth cavity, were detected in these organs.

[Adrenal cortex hormones in the mother and fetus in premature labor]. / Hormóny nadoblickovej kôry matky a plodu pri predcasných pôrodoch.

In a group of 126 pregnant women with imminent premature delivery between the 20th and 37th week of gestation where after weekly intervals the serum cortisol and corticosterone levels from the cubital vein was assessed, it was revealed that in the group of women who aborted or had a premature delivery, as well as in women who had the delivery in term the corticoid values vary greatly: cortisol between 370 and 500 nmol/1 and corticosterone 70 to 240 nmol/1. In both groups there is a marked difference in final values. The latter have in women with premature deliveries a rising trend and in the group where pregnancy proceeded successfully to term a declining trend. Glucocorticoid blood levels from the umbilical arteries in the group of women who had an abortion or premature delivery, as compared with women who delivered their baby in term, no significant differences were recorded. However, the glucocorticoid blood levels from the umbilical veins were significantly higher in women who had premature deliveries or abortions, as compared with women who gave birth to their babies in term. The glucocorticoid levels in amniotic fluid collected during delivery did not manifest significant differences between the two groups of pregnant women.

[The effect of prolonged starvation on changes in the activity of selected adaptive enzymes in rat liver]. / Vplyv prolongovaného hladovania na zmeny aktivity vybraných adaptívnych enzýmov v peceni potkanov.

Male rats of Wistar SPF stain (Velaz Prague) were used to investigate the influence of prolonged starvation on changes in the activity of selected adaptive enzymes in the liver and corticosterone in serum. Analyses were carried out on days 1,2,3,5 and 7 of starvation. The activity of tyrosine aminotransferase significantly increased in the period between days 2 and 5 of starvation, after which a decrease to the level of satiated animals was observed in the terminal period. Activities of tryptophane-2-3-dioxygenase and alanine aminotransferase increased in two phases reaching maximum values on days 2 and 7 of starvation. The activity of aspartate aminotransferase showed a progressive significant increase in dependence on the length of starvation. A more than threefold increase in corticosterone concentration was observed in the serum of starved animals in comparison with satiated rats.

Thymus lipids in continuously irradiated rats.

Male Wistar rats were irradiated continuously with a daily dose of 0.19 Gy (120 days), 0.57 Gy (90 days) and 0.96 Gy (35 days) of gamma rays. An other group of rats was irradiated continuously with graded doses of gamma rays, up to total exposures ranging from 3.83-19.15 Gy. Depending on both the daily dose and total exposure, there was a decrease in phospholipid content in the thymus which correlated well with thymus weight changes. The decrease in triacylglycerol content was a less reliable sign of radiation damage. The phospholipid content reflecting the patterns of organ cellularity is a valuable indicator of the extent as well as recovery from radiation-induced injury to the thymus.

The circadian and circa-annual response of rat serum corticosterone to different stressors.

The serum corticosterone (B) response to shortlasting immobilization and the administration of ACTH was studied during the year, at the beginning of the light and dark part of the day, in SPF Wistar rats of both sexes kept under standard conditions with a 12:12 h light and dark regimen. Both sexes reacted to the stressors (mainly immobilization) by a marked increase in B at the beginning of the light period. The maximum reaction, to both immobilization and ACTH, was found in males in the spring; females reacted more evenly throughout the year, with a maximum in the winter. The reactivity of both sexes was the lowest in the summer. Circadian and circa-annual differences in the reactivity of the laboratory rat are genetically (evolutionally) fixed and must be taken into account when evaluation the results of experiments.

Circaseptan rhythm of corticosterone and lipids in the serum of male rats.

After adaptation to standard conditions and to a 12:12 h light: dark regimen, groups of young SPF male Wistar rats were killed at 8 h on 17 consecutive days and their serum corticosterone and lipid concentrations were determined. Using a combination of a Fourier harmonic analysis and an analysis of variance, the circaseptan rhythm of corticosterone, total cholesterol and triacylglycerol oscillations was determined; it is unlikely that the nonesterified fatty acid concentration has a 7-day rhythm. The circaseptan variation of metabolic and hormonal indicators is evidently adaptive in character and its existence ought to be taken particularly into account in the evaluation of long-term experiments.

Correlation of circadian changes in tyrosine aminotransferase and tryptophan-2-3-dioxygenase in rat liver to irradiation at different times of the day.

Male SPF Wistar rats adapted to a 12:12 h light: dark regimen were irradiated at 3-hour intervals in the course of 24 h with a dose of 14.35 Gy X-rays; 24 h after irradiation or sham irradiation and starvation for the same length of time, and also in fed intact rats, tyrosine aminotransferase and tryptophan-2-3-dioxygenase activity in the liver and the serum corticosterone level were determined. Although lethal irradiation modified the given enzyme activities, it did not abolish their circadian rhythm, evidently in association with the low sensitivity in association with the low sensitivity of the liver to ionizing radiation. In irradiated animals (compared with sham-irradiated animals), the serum corticosterone concentration fell during the light part of the day and at the beginning of the dark part.

Circadian oscillations of thyroid hormones and insulin in the serum of fasting rats.

Adult male Wistar rats adapted to a 12:12 h light:dark regimen, fed or after a 24- or 48-h fast, were decapitated at 3-h intervals during a single day. They were deprived of food at day-time intervals ensuring that on decapitation they had fasted for the same length of time, i.e. 24 or 48 h. Thyroid hormones, insulin and glucose concentrations were determined in their serum. Fasting did not significantly affect circadian thyroxine, triiodothyronine and reverse triiodothyronine rhythms compared with the findings in fed animals; 24, but not 48 hours' fasting led to a shift in the acrophase of circadian insulin and glucose oscillations compared with fed rats. The maintenance of original circadian thyroid hormones and insulin rhythm in rats which fasted for short lengths of time testifies to a dependence of the stimulus on the time of day.

Circadian rhythm of ketone bodies in the blood of fasting rats.

SPF male Wistar rats were kept under standard conditions with a light: dark schedule of 12:12 h. The total ketone body concentration was determined in the blood, and the non-esterified fatty acid level in the serum, of fed rats and of animals which had fasted 24 and 48 h. The amount of ketone bodies in fed rats rose in the second half of the light period and fell with the onset of the dark period. After a 24 h fast, the amount of ketone bodies in the blood rose, but the basic characteristics of the curve and the rhythm remained the same as in fed animals. After a 48 h fast, the mean ketone body concentration was decoupled, a significant phase shift occurred and the rhythm was lost. No relationship between the oscillations of the total ketone body concentration in the blood and the oscillations of the serum non-esterified fatty acid level was found.

[Effect of restricted feeding on metabolic changes in lipids following a single lethal irradiation of rats]. / Vliianie ogranichennogo kormleniia na metabolicheskie izmeneniia lipidov posle odnokratnogo letal'nogo oblucheniia krys.

A study was made of the influence of adaptation of rats to limited feeding (2 h a day during 3 weeks) and the response of the adapted animals to total-body X-irradiation with a lethal dose of 14.35 Gy. The concentration of unesterified fatty acids in the blood and the total cholesterol content were shown to decrease between the 1st and 24th hours following irradiation: the content of phospholipids decreased 60 min after irradiation. In the bone marrow of rats adapted to limited feeding, a more pronounced accumulation of triacylglycerols was noted as late as 72 h after irradiation.

Circadian oscillations of thyroid hormones, insulin and glucagon in the blood of laboratory rats in the course of the year.

The concentration of thyroid hormones and insulin in the serum that of glucagon in the plasma and glucose in the blood was determined at 3-hour intervals, in the course of one day, at different times of the year, in adult male rats (Wistar strain) of a conventional breed kept under standard conditions with a 12:12 h light:dark regimen. The lowest thyroid hormone and glucagon concentrations and the highest insulin and blood glucose levels were found in the winter. In various seasons, circadian oscillations of the thyroid hormones culminated in the dark part of the day and that of glucagon in the light part, with the exception of the autumn. Circadian oscillation of insulin levels culminated at different times of day during the year. The pronounced changes found in the examined hormones in the laboratory rat at various times of the year are evidently the outcome of adaptation to changes in external environmental conditions during phylogenesis. In the polarity of changes in these indicators between the winter and the summer or the spring, the laboratory rat bears the closest resemblance to wild mammals.

Effect of food synchronization on the circadian rhythm of bone marrow and thymus lipids in rats.

Young male Wistar rats reared under standard laboratory conditions with a 12:12 h light:dark regimen were fed ad libitum or were allowed access to food for only 2 h in the first half of the light or the dark part of the day. In rats fed ad libitum, marked circadian oscillation of the bone marrow triacylglycerol and phospholipid concentration and oscillation of the same fractions in the thymus were found. The restricted feeding time raised the triacylglycerol concentration in the bone marrow, but did not noticeably affect the time course of the circadian curves. The mean lipid values in the thymus of animals with a shortened feeding time did not alter, but the acrophase of the two basic fractions shifted.

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.

[Plasma and tissue lipids in rats after a flight on the Kosmos-1129 biosatellite]. / Plazmatichesie i tkanevye lipidy u krys posle poleta na biosputnike "Kosmos-1129".

Concentrations of triglycerides, total cholesterol, lipid phosphorus and nonesterified fatty acids were measured in blood plasma, liver, thymus, bone marrow and adipose tissues of rats flown for 18.5 days onboard the biosatellite Cosmos-1129. This exposure was accompanied by increases in lipomobilization, content of total cholesterol and lipid phosphorus in plasma, and triglycerides in the thymus and bone marrow. The postflight exposure to repeated stresses demonstrated changes in the lipid content in all animal groups, especially in flight rats.