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Biomedical subjects

E A Savina

Publications and source records attributed to E A Savina.

At least 19 recordsLinked to original sources
PubMed1980

[Functional state of the posterior lobe of the neurohypophysis of rats exposed aboard the biosatellite "Cosmos-936" (according to the results of morphologic studies)].

A comparative evaluation on some morphological indices of functional state of the posterior neurohypophysis was performed in rats subjected to weightlessness and artificial gravitation for 18.5 days on board the biosatellite "Cosmos-936". The data of the investigation were compared to those obtained on the test animals used for terrestial series of the experiment where all the factors of space flight, except weightlessness were imitated. As the analysis of morphological data demonstrated, a prolonged effect of weightlessness results in a considerable decrease in the number of the neurosecretory cumulative corpuscles (Herring's bodies), in decreasing volume of nuclei and size of pituicytes. A suggestion is made on decreasing basal level of functional activity of the hypothalamo-hypophyseal neurosecretory system under the conditions of weightlessness. Administration of artificial gravitation (lg) levels partly the changes produced by weightlessness and ensure a higher level of functioning in the neurosecretory system.

Animals↗
PubMed1980

[Reactions of the adrenal cortex to immobilization stress in intact animals and against a background of hypokinesia].

Morphological investigation of the rat adrenal cortex and corticosterone contents in the blood plasma demonstrated certain peculiarities in the adrenal reaction to the primary and repeated immobilization stress in intact animals and after hypokinesia. It has been stated that morphological manifestation to an acute stress reaction kinesia is less pronounced than at an analogous single effect. Investigation on corticosterone content in blood plasma revealed certain functional peculiarities in the adrenal cortex reactions in different variants of the experiments. Five hours after the beginning of the stress, corticosterone content was increased only at the initial immobilization, while at repeated stimulations during the same time it did not differ from the control. Changes in functional possibilities of the adrenal cortex in response to a repeated stimulation and in response to a new stimulation in animals previously adapted to another type of stress are discussed.

Adaptation, Physiological↗
PubMed1980

[Effect of weightlessness and artificial gravitation on morphological manifestations of the adrenal cortex reaction in rats after space flight on board the biosatellite "Cosmos-936"].

Comparing the changes revealed in the adrenals of rats subjected to weightlessness and artificial gravitation, it has been stated that rotation of the animals in the centrifuge, while flying (with an acceleration of lg), prevents development of morphological stress reaction as a response to landing. After the effect of weightlessness, return to normal gravitation is accompanied with definite signs of an acute stress-reaction in the rat adrenal cortex. Differences in the adrenal reaction of the animals of the groups compared speak in favour of the fact that application of artificial gravitation in an orbital space flight contributes to level the changes resulting from weightlessness and, hence, increase the organism's stability to stress effects, while returning to the Earth.

Adrenal Cortex↗
PubMed1978

[Morphologic study of rat adrenals following flight aboard biosatellites "Cosmos-605" and "Cosmos-782"].

Dynamics of morphological changes of the rat adrenals was investigated on the first day and 25--27 days after a prolonged exposure to weightlessness. Analysing the general histological picture of the adrenal cortex during the first hours of the flight (presence of a subglomerular sudanophilic layer and distinct zones in other cortical parts), it is possible to conclude that by the completion of the flight the cortical substance has reached a definite degree of normalization, hence the animals have adopted to the flight conditions. Morphological signs of elevated functional cortical activity 9--11 h after the flight, such as enlarged nuclear volume of the fascicular zone cells and delipoidization of the internal parts of the cortex could be treated as manifestation of an acute stress-reaction developing in the animals after landing. Evaluating morphological manifestation of the acute stress-reaction observed in animals at transition from weightlessness to the earth level of gravitation, it is possible to conclude that there are no signs of depletion in the adrenal cortical function and hence, adaptive possibilities in the organism are preserved after a prolonged exposure to weightlessness.

Acute Disease↗
PubMed1977

Discussion of the combined effect of weightlessness and ionizing radiation on the mammalian body: morphological data.

The combined effect of weightlessness and ionizing radiation, from the Cs137 source at 800 rads for 24 h, on the animal body was studied. The morphological examination of organs and tissues of rats flown aboard the biosatellite Cosmos-690, kept in the ground-based simulation experiment, and kept in the vivarium, indicated prevalence of radiation-induced changes in both experimental groups of rats. An exposure of animals to space flight factors did not produce a substantial aggravation of radiation-induced effects. This is indicated by the lack of significant differences in the weight of testes, thymus, and spleen of flight and simulation rats. However, this exposure affected adversely the development of reparative processes in the hemopoietic tissue of bone marrow. Inflight irradiation aggravated weightlessness-induced changes. A combined effect of weightlessness and irradiation did not result in the summation of the effects exerted on skeletal muscles by either factor alone.

Animals↗
PubMed1976

Effect of space flight factors on the mammal: experimental-morphological study.

On the basis of a morphological examination of 27 rats that made a space flight and were sacrificed on the 1st-2nd and 26-27th days postflight, it has been shown that the 22-d space flight has produced no significant changes in the structural organization of vital organs of the animals. However, a space flight exposure is not indifferent for animals and leads to the development of morphologically visible changes in individual organs and systems (musculo-skeletal system, hemopoietic organs, hypothalamic-pituitary-adrenal system, renal juxtaglomerular system). The detected changes are reversible, nonspecific, and develop in animals exposed to ground-based hypokinetic and other stress experiments.

Adrenal Glands↗
PubMed1976

Morphological manifestations of functional changes in the hypothalamic-pituitary neurosecretory system and kidneys of rats after space flight.

Morphological examination of the hypothalamic-pituitary neurosecretory systen and kidneys of rats flown for 22 d and sacrificed 2 and 27 d postflight was carried out. By histological and histochemical methods, indications of increased activities of the hypothalamicpituitary neurosecretory system and the juxtaglomerular apparatus of kidneys were found. The changes were reversible and by the 27th postflight day returned to the normal. It is suggested that the changes in the above systems may be produced not only by flight effects but also by readaptation of animals to 1 g.

Animals↗
PubMed1975

Preliminary results of examinations of rats after a 22-day flight aboard the Cosmos-605 biosatellite.

The results of biomedical investigations carried out in flights of the Salyut and Skylab orbital stations give evidence that during prolonged weightlessness cosmonauts and astronauts remain in a good physical and mental condition. They fill specialists with optimism in regards to a further increase of the duration of manned space flights. In order to make reliable plans for such missions, it is necessary to accumulate detailed knowledge about the mechanism of the effect of weightlessness on different functions of the human body. In addition to manned experiments, of great interest are animal experiments. They may yield data that cannot be obtained in human studies, which is obviously very important from the point of view of space medicine. This was the purpose of the experiment carried out in November 1973 on the biosatellite Cosmos-605; 45 rats aboard the biosatellite flew for 22 d. Preliminary results of examinations of rats after a 22-d space flight in the Cosmos-605 satellite demonstrated not only physiological and biochemical but also morphological changes in the animal body due to prolonged weightlessness. These changes were reversible.

Aerospace Medicine↗
PubMedDate not supplied

[Characteristics of morphological reactions in dog internal organs and endocrine glands during 6-year gamma irradiation].

Dogs were exposed to six-year gamma-irradiation with doses of 21-1140 rad/year; pathomorphological changes were studied in testicles thyroid gland, adrenals, liver and kidneys. The level of morphological changes in the organs during the six-year exposure was dissimilar and depended on the radiosensitivity of a specific organ, dose rate and acute irradiations that were applied during the experiment. In testicles morphological changes (reduction of layers of the spermatogenous epithelium, decrease of the number of spermatozoids in testicular canals) appeared during the first year of irradiation at a dose rate of 0.34 rad/day. Later, these changes progressed and by the end of the six-year exposure were followed by a distinct sclerosis of the interstitial tissue and hyperplasia of Leydig's cells. In the thyroid gland signs of the hypofunctional state were seen by the end of the second year of irradiation at a dose rate of 0.34 rad/day and persisted afterwards. In adrenals hypertrophy of the bundle and glomerular zones were observed during the second-fourth years of irradiation at a dose rate of 0.34 rad/day. As irradiation proceeded hyperplastic processes developed in the thyroid gland and adrenals (adenomatous nodes in the thyroid gland, adenomatous hyperplasia in the adrenal cortex). Vacuolar and fat dystrophy of hepatocytes and disturbed permeability of glomerular capillaries in the kidneys were detected only at the end of the third year of irradiation. During the fifth and, particularly, the sixth year of the exposure sclerotic changes in the liver vessels, hyalinosis of small arteries and nephrosclerotic foci in the kidneys were found.

Adrenal Glands↗
PubMedDate not supplied

[Experiments using rats on Kosmos biosatellites: morphologic and biochemical studies].

Results of morphological and biochemical investigations of rats flown on Cosmos biosatellites are discussed. It is emphasized that most changes occurring during exposure to microgravity are directly or indirectly related to lower musculoskeletal loads which in turn produce deconditioning of different physiological systems and organism as a whole. It is concluded that this deconditioning is associated with both metabolic and structural changes.

Adaptation, Physiological↗
PubMedDate not supplied

[Experiments on rats exposed in the Cosmos 1667 biosatellite (goals, protocols, results)].

Morphobiochemical investigations of the rats flown on the biosatellite Cosmos-1667 have shown that the 7-day space flight produces shifts in different systems, organs and tissues which reflect adaptive processes to microgravity. Early signs of structural, functional and metabolic rearrangement can be detected in the musculoskeletal apparatus, hemopoietic system, lymphoid organs, neurohormonal systems, i.e., in the systems and organs that develop changes during long-term flights. The rates of adaptation to microgravity are different not only in various systems and organs but also within the same tissues. Most shifts that emerge at an early stage of adaptation to microgravity progress with flight time but some of them develop to a full extent after the 7-day flight. The specific feature of the early stage of adaptation to microgravity is the lack of significant changes in blood biochemistry in the presence of structural and metabolic changes in tissues. This fact gives evidence that the mechanisms maintaining homeostasis at the organism level are not as yet disrupted during 7 days of flight.

Adaptation, Physiological↗
PubMedDate not supplied

[Head-down tilt hypokinesia in monkeys: a morphological study].

Morphological examinations of rhesus monkeys (Macaca mulatta) exposed to head-down tilt for 7 and 19 days are summarized. The major changes detected in various systems, organs and tissues are described. The changes are thought to be of different origin and caused by blood redistribution, hypokinesia per se and concomitant stress. It is emphasized that head-down tilt is one of the most adequate methods for simulating effects of zero-g in monkeys.

Animals↗
PubMedDate not supplied

[Thyroid and C-cell system function during prolonged rotation (morphobiochemical research)].

The thyroid and parathyroid glands of 65 Wistar rats centrifuged for 30 days at 1.1 and 2.0 G were examined histologically and biochemically. The centrifugation led to a higher activity to C-cells, an increased rate of thyro-calcitonin (TCT) synthesis and excretion, i.e. C-cell degranulation, and a significant (two-fold) increase of TCT in plasma. The stimulation effect of the TCT-producing system persisted during 7-post-rotation days and was very distinct in the animals exposed to 2.0 G. There were no morphological changes in the parathyroid glands or in the PTH concentration in the plasma.

Animals↗
PubMedDate not supplied

[Morphological study of the adrenals of rats exposed on the Kosmos-690 satellite].

Adrenals of 12 rats flown aboard the biosatellite Cosmos-690 and 30 rats used in the ground-based experiments Control-1 and Control-2 were studied morphologically. The animals were sacrificed on the 2nd and 27th days after completion of the experiments (i. e., on the 12 and 37th days after irradiation at a total dose of 800 rad). A comparative study of morphological changes in the adrenals of flight and control rats did not show any distinct differences. It is therefore concluded that space flight factors did not produce a significant effect on the adrenal response to irradiation at a dose of 800 rad.

Adrenal Cortex↗