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Biomedical subjects

O G Gazenko

Publications and source records attributed to O G Gazenko.

At least 55 records · Page 3Linked to original sources

Results of medical investigations carried out on board the Salyut orbital stations.

The purpose of the medical investigations carried out in flights of the Soviet orbital station Salyut were: to further studies and clarification of the phenomenology and mechanisms of changes in the main functions of the human body during prolonged weightlessness; to accumulate additional data on human responses at an early stage of adaptation to weightlessness; to assess the effectiveness of countermeasures against adverse effects of weightlessness during and after flight. The orbital station was equipped with a set of countermeasuring devices: a trainer for physical exercises (a treadmill), gravity simulation suit for long wear, bicycle ergometer, anti-G suit to be worn immediately post-flight, drugs, etc. The system of medical control included daily recordings of electrocardiography and respiration and regular physical examinations using provocative tests (physical exercises of a known force, lower-body negative pressure). Specific biomedical investigations were performed before, during and after flight. As in previous flights, the atmosphere in the habitable modules was similar to that on the earth. Food supply met the requirements for basic nutrients and satisfied individual preferences of the crew members. In addition to the time required to fulfil the flight programme, the work-rest schedule allowed the cosmonauts 8 hours sleep, four meals, 2.5 hours physical training and personal time. The biomedical investigations carried out during and after flight furnished information towards a better understanding of human responses to the effects of space flight factors and the mechanisms underlying their development.

Adaptation, Physiological↗

The role of gravity in the phylogeny of structure and function in animal sensors of spatial orientation, and their predicted action in weightlessness.

The evolution of the structural, functional and cytochemical organization of the gravity receptor which determines a body position in the gravitational field of the earth by means of muscular regulation was traced both invertebrates and vertebrates, using electron microscopic and histochemical methods. In the course of evolution of vertebrates, the specialized gravity receptor-statocyst which, as a rule, consists of primary sensory cells and supplies otoliths, is formed. In vertebrates, there exists a vestibular apparatus made up of secondary sensory cells and also having otoliths. The receptor cells, both of statocysts and the vestibular apparatus, are supplied with special antennas (kinocilia and stereocilia). Deviation of the antennas stimulated by displacement of the otoliths resulting from locomotor activity of animals leads to excitation of the receptor cells. When exposed to a modified gravitational field (linear accelerations of 10 g, for 3 min), the receptor cells of the vestibular apparatus, in all classes of vertebrates, show progressive changes in RNA content and protein synthesis (increase followed by decrease) which return to normal only after 12 days. Thus, immediate transfer of animals and man from acceleration to weightlessness appears to be a reason for movement disease. The above consideration showed the need for an experiment in which an animal (with its vestibular apparatus) which had not undergone previous accelerations, would be exposed to weightlessness. Frog embryos, Rana temporaria, at the stage preceding the organogenesis, when the vestibular apparatus and other organs were lacking, were chosen as a suitable subject. Frog embryos at the stage of an early gastrula were placed in a special container Emkon aboard the Soyuz 10 spacecraft. After short accelerations, they were exposed to weightlessness for 44 hours. The embryos were allowed to continue to develop to the stage of early tail bud. The experimental embryos showed normally developed acoustic vesicles and vestibular ganglia. Clear differentiation of the receptor cells with antennas (kinocilia and stereocilia) was found in the acoustic vesicles. Thus, in weightlessness, vestibular apparatus develops just as well as in the gravitational field of the earth. However, only a much longer stay in weightlessness conditions will indicate whether there are any changes in the structural, cytochemical and functional organization of vestibular apparatus. The similarity in the structural, functional and cytochemical organization of the gravity receptor in vertebrates and invertebrates appears to allow the prediction of the behaviour of the gravity receptor as a whole, and of its receptor elements, both in normal and changed gravitational fields. The first attempts were carried out only on the vestibular apparatus of vertebrates.

Acetylcholinesterase↗

Some results of medical investigations performed during the flight of the research orbital station Salyut.

The paper presents the main results of physiological studies carried out during the flight of the Salyut station. Details of atmospheric composition, diet, provisions for personal hygiene, the on-board medical kit, prophylactic measures, work and rest schedule are given. Methods of investigation, particularly for studying the cardiovascular response, are described, including tests using the application of lower body negative pressure. The subjective and objective in-flight condition of the cosmonauts is dealt with in detail. An evaluation of the cardiovascular response is made, as compared with previous flights, both at rest and during tests. Results of clinical and biochemical studies of the blood, certain indices of visual perception and microbiological investigations are described. It is concluded that the observed physiological changes are reversible.

Adaptation, Physiological↗

Physiological effects of gravitation.

The physiological effects of weightlessness are discussed, as they were measured and reported by the Russian cosmonauts. The possibilities of adaptation to space environment by training and the mechanisms of compensation and vicarization (adaptive substitution) of the analyzers and processes of the biological entity are considered. The authors present recommendations for cosmonaut training for distant and prolonged flights.

Acceleration↗

Satellite biological experiments--major results and problems.

The data on the results of biological experiments carried out on Vostok 5 and Vostok 6 are presented. Space flight factors are shown to cause in hereditary structures of some biological objects (seeds of higher plants, lysogenic bacteria, Tradescantia microspores, etc.) distortions of a small but statistically significant value. Changes in physiological functions of certain objects (seeds of higher plants, etc.) have been also detected. These data are in good agreement with the results of flight experiments carried out in 1960-1962. Prospects of research of the biological effect of cosmic radiation and weightlessness are considered with respect to flight experiments.

Animals↗

On the biological role of gravity.

The paper is dedicated to the memory of Galileo Galilei whose work is a great contribution to the development of a new branch of science--gravitation biology. Penetration of man into outer space necessitates a study of the role of gravity in the onto- and phylogenetic development of living organisms. This allows one to get insight into the biological action of weightlessness under the conditions of long-term space flight. The paper summarizes some results of the investigation of weightlessness effects in experiments on animals and during flights of Soviet and American astronauts. The rearing of animals in a special centrifuge under the conditions of prolonged action of accelerations simulating an increased gravity affects noticeably the formation of vegetative (height, weight, metabolism) and animal (vestibulo-tonic reflexes) functions as well as reactivity of the organism. Experiments employing the rearing of animals in a centrifuge represent one of the most promising methods of studying the urgent problem--biological action of increased and decreased gravitation conditions.

Acceleration↗

Soviet experiments aimed at investigating the influence of space flight factors on the physiology of animals and man.

Results are given of biological experiments on space ship-satellites II, III, IV and V, and of scientific investigations made during the flights of Cosmonauts Gagarin and Titov aboard space ships Vostok I and Vostok II. Physiological reactions to the action of the flight stress-factors are not of a pathological character. In the post-flight period no alterations in health conditions of either cosmonauts or animals were observed. At the same time some peculiarities which were revealed while analyzing physiological reactions and a number of biological indices require further investigations. The most important tasks remaining are to study the influence of protracted weightlessness, of the biological action of space radiation, of the action of acceleration stresses after prolonged stay under zero-gravity conditions and also to analyze the influence on the organism of the whole combination of spaceflight factors, including emotional strain. In the Soviet Union, a great number of biological experiments have been conducted with a view to elucidating the action of space flight factors on living organisms and the design of systems necessary to ensure healthy activity during flight aboard rocket space vehicles. The first flight experiments with animals were conducted by means of geophysical rockets. The next step in this direction was made by the launching of Sputnik II in 1957 and by experiments on space ship-satellites in 1960-61. The main purpose of flight and laboratory investigations was to obtain the objective scientific criteria essential for ensuring the safety of manned space flight.

Adaptation, Physiological↗

Summary of medical investigations in the U.S.S.R. manned space missions.

The results of biomedical investigations carried out in the U.S.S.R. manned space missions are discussed. Their basic result is well-documented evidence that man can perform space flights of long duration. The investigations have demonstrated no direct correlation between inflight or postflight physiological reactions of crewmembers and flight duration. In all likelihood, this can be attributed to the fact that special exercises done inflight efficiently prevented adverse effects of weightlessness. However, human reactions to weightlessness need further study. They include negative calcium balance and anemia as well as vestibulo-autonomic disorders shown by crewmembers at early stages of weightlessness. Attention should be given to psychological, social-psychological and ethical problems that may also limit further increase in flight duration.

Adaptation, Physiological↗

The structural and functional organization of the vestibular apparatus of rats exposed to weightlessness for 20 days on board the Sputnik "Kosmos-782".

This investigation of the vestibular apparatus of rats exposed for 20 days to weightlessness on board an earth satellite and to acceleration during take-off and landing has revealed a set of changes in the structural and functional organization, such as adjoinment of the otolith to the utricle receptor surface and peripheral localization of the nucleoli inside the receptor cells' nuclei. Destruction of some receptor cells, apparently due to increased swelling of the vestibular apparatus tissue and alteration of the shape and structure of the otoconia were observed. In the horizontal crista, detachment of the cupula took place.

Acceleration↗

[Medical studies during flights of "Soiuz-12", "Soiuz-13", "Soiuz-14" space ships and "Saliut-3" orbital station].

Medical results obtained during missions of the Soyuz-12, Soyuz-13, Soyuz-14 spacecraft and the Salyut-3 orbital station are presented. The subjective feelings of the crewmembers (blood rush to the head, chest congestion, vegetative disturbances, etc), data of the inflight medical control and medical experiments as well as countermeasures used are described in detail. Results of postflight medical examinations at rest and using functional tests are also summarized. It is concluded that no abnormalities in the vital physiological functions of the crews developed inflight. The symptoms typical of the acute period of adaptation to weightlessness disappeared completely after the first flight days.

Aerospace Medicine↗