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Biomedical subjects

O G Gazenko

Publications and source records attributed to O G Gazenko.

At least 37 records · Page 2Linked to original sources
PubMed1984

Investigations on-board the biosatellite Cosmos-83.

The program of the 5 day flight of the biosatellite Cosmos-1514 (December 1983) envisaged experimental investigations the purpose of which was to ascertain the effect of short-term microgravity on the physiology, growth and development of various animal and plant species. The study of Rhesus-monkeys has shown in that they are an adequate model for exploring the mechanisms of physiological adaptation to weightlessness of the vestibular apparatus and the cardiovascular system. The rat experiment has demonstrated that mammalian embryos, at least during the last term of pregnancy, can develop in microgravity. This finding has been confirmed by fish studies. The experiment on germinating seeds and adult plants has given evidence that microgravity produces no effect on the metabolism of seedlings and on the flowering stage.

Adaptation, Physiological↗
PubMed1984

Fluid-electrolyte metabolism and renal function of white rats in experiments aboard Cosmos biosatellites.

Rat experiments on the Cosmos biosatellites demonstrated that the percentage of renal excretion of consumed water after flight was lower than after synchronous experiment. This can be attributed not only to water retention but also to a different level of extrarenal losses postflight. Weightless rats showed increased sodium excretion after water load tests and increased potassium excretion after potassium load tests. The sodium, potassium, and calcium balance was positive after weightlessness. Analysis of the electrolyte composition of different kidney zones revealed a decreased potassium content in the medulla, which is considered to be one of the causes of changed renal iono- and osmoregulatory function in weightlessness. The normalizing effect of artificial gravity on the natri- and kaliuretic renal function was demonstrated.

Animals↗
PubMed1983

Medical results of Salyut-6 manned space flights.

The major goal of medical investigations in the USSR longterm (up to 6 months) manned space flights was to accumulate information on human responses to prolonged weightlessness. Before, during and after these flights, detailed clinical, physiological, immunological and anthropometric examinations were conducted. The examinations demonstrated that man may well adapt to long-term space flight, retaining good health and a high work capacity. The changes seen postflight were reversible and disappeared completely after a relatively short readaptation period. Postflight changes did not correlate with the flight duration. A reasonable work-rest cycle and various physiological countermeasures were used, the efficiency of which were substantiated by means of regular medical examinations. These methods helped the cosmonauts to maintain good health status and adequate performance inflight and facilitated their readaptation postflight. Medical investigations performed during the Salyut-6 flights indicate that the duration of manned space flight can be increased.

Aerospace Medicine↗
PubMed1982

Effects of various countermeasures against the adverse effects of weightlessness on central circulation in the healthy man.

The effect of lower body negative pressure, local negative pressure below the knee joint, and both pneumatic and mechanical occlusion cuffs at the upper third of the femur on central circulation, oxidative metabolism, and acid-base equilibrium of blood was studied on eight healthy male volunteers with doublelumen Swan-Ganz flow-directed thermodilution catheters implanted for 7 d into the pulmonary artery. The counter-measures against the adverse effects of weightlessness were used in two regimens: regimen I at -30, -50, +40 torr and regimen II at -60, -100, and +60 torr. The parameters were recorded in recumbency, during the head up tilt at 70 degrees for 15 min, and then during the head-down tilt at -20 degrees for 60 min. After the first 20 min of anti-orthostasis, the effects of the above countermeasures in the two regimens were investigated. The tile-induced changes in central circulation, those observed during application of the countermeasures, and the effect of different countermeasures were studied on a comparative basis. It was demonstrated that the highly informative method of implantation of catheters into the pulmonary artery can be successfully used in biomedical investigations of normal men.

Acid-Base Equilibrium↗
PubMed1980

Study of physiological effects of weightlessness and artificial gravity in the flight of the biosatellite Cosmos-936.

In the 18.5-day flight of the Soviet biosatellite Cosmos-936 (3-22, August 1977) com-parative investigations of the physiological effects of prolonged weightlessness (20 rats) and artificial gravity of 1 g (10 rats) were carried out. Throughout the flight artificial gravity was generated by means of animal rotation in two centrifuges with a radius of 320mm. Postflight examination of animals and treatment of the flight data were performed by Soviet scientists in collaboration with the specialists from Bulgaria, Czechoslovakia, the German Democratic Republic, Hungary, Poland, Rumania, France and the U.S.A. During the flight the total motor activity of the weightless rats was higher and their body temperature was lower than those of the centrifuged animals. Postflight examination of the weightless rats showed a greater percentage of errors during maze an increase in water intake and a decrease in diuresis; a fall of the resistance of peripheral red cells; an increase in the conditionally pathogenic microflora in the mouth; a decrease of oxygen consumption, carbon dioxide production and energy expenditures; a drop in the static physical endurance; a decline in the capacity to keep balance on the rail; an increase in the latent period of the lifting reflex, etc. The centrifugal animals displayed lesser or no change of the above type. These findings together with the biochemical and morphological data give evidence that during and after flight adaptive processes in the centrifuged rats developed better.

Adaptation, Physiological↗
PubMed1978

[Structural and functional organization of the vestibular apparatus in rats maintained under weightless conditions for 19.5 days aboard the satellite "Cosmos-782"].

Vestibular apparatus was investigated in rats subjected to weightlessness for 19.5 days in the satelite "Cosmos-782" and experienced acceleration on launching and landing. Some structural and functional changes were noted. They were seen in otolith clinging to the utricular receptor surface and in the peripheral arrangement of the nucleolus in the nuclei of the receptor cells. It is also possible that increased edema of the vestibular tissue resulted in destruction of some receptor cells, and within the otolith--changes in the form and structure of otoconia. In the horizontal crista the cupula was separated.

Acceleration↗
PubMed1978

Radiobiological experiment aboard the biosatellite Cosmos-690.

In 1974, the USSR launched the biosatellite Cosmos-690 equipped with a gamma-irradiation unit that carried 35 rats. On the 10th flight day, the rats were exposed to radiation at doses of 220 or 800 rads. During the subsequent 10 d, radiation injury developed in a space environment. Similar ground-based experiments were carried out to simulate space flight environment effects. The results obtained were studied on a comparative basis. The conclusion is made that effects of a short-term space flight, as long as 20 d, do not essentially modify the radiobiological effect.

Animals↗
PubMed1977

Preliminary results of medical investigations during manned flights of the Salyut 4 orbital station.

In 1975 the Soviet Union performed two manned flights on board the orbital station Salyut 4. The first mission of 30 days was flown by A. A. Gubarev (Commander) and G. M. Grechko (Flight Engineer) and the second mission of 63 days by P.I. Klimuk (Commander) and V.I. Sevastyanov (Flight Engineer). The present paper gives preliminary data on the general health and cardiovascular investigations of the crew members during and after flight. The clinical and physiological examinations of the cosmonauts showed that the work-rest cycles and counter-measures used helped to maintain their good health and high performance in flight, to alleviate adverse reactions and to facilitate readaptation post-flight. Medical results of the post-flight investigations revealed no changes that may detract from further increasing the duration of manned space missions.

Adaptation, Physiological↗
PubMed1976

[The development OF THE vestibular apparatus under conditions of weightlessness].

The spawn of the aquarium fish Brachydanio rerio was developing during 5--6 days under conditions of weightlessness (first on board the spaceship "Sojuz-16", then in the space station "Salut-4") in special aquariums "EMKON", in thermostable installations. Electron microscopically the embryos were found to have a well developed labyrinth in early developmental histologically and cytologically differentiated receptory structures of the macula utriculi and macula saccili. In contrast to controls, the experimental animals showed certain alterations in the otolite organization. In similar experiments the embryos of clawed frog Xenopus laevis in the stage of the tail bud were also placed in special containers "EMKON" and thermostable apparatus "Biotherm-4" and by the spaceship "Sojuz-17" were brought to the space station "Salut-4", where it stayed for 16 days. The initial embryos had already had a well developed acoustic vesicle with macula communis. Inspite of the preliminary load by start acceleration and staying under conditions of weightlessness, they reached the general development fairly similar to controls. As it was shown electron microscopically their labyrinth had highly histologically and cytologically differentiated structures. However, a disturbance of the development of the otolithic membrane and otoconia should be noted. The alterations observed in the otolithic membrane organization in experimental fishes and frogs may be explained by general disorders in calcium metabolism.

Animals↗