Biomedical subjects
Publications and source records attributed to V V Antipov.
The effect of indralin on frequency of mutations induced by radiation in germ cells, reciprocal translocations, and testicle weight of male mice. The level of protective effect against genetic damage varied depending on the radiation dose and spermatogenesis stage. The values of the defense coefficient ranged from 0.16 to 0.35.
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The space radiobiology program in Russia is aimed at obtaining fundamental data for developing radiation safety criteria. These criteria are necessary for long-term space missions. This program includes : -substantiation of radiation hazard estimation principles based on the radiation risk conception, -investigation of the radiation affection regularities under the combined influence of the spaceflight factors, -experimental investigation of the HZE-particle delayed effects and acute somatic effects induced by protons and electrons, -individual radiosensitivity investigation, -mathematic modeling of radiobiological effects , -radiobiological basis of control and forecast of radiation influence in space, -development of methods and means of an organism's radioresistance increase.
In order to reveal the biological significance of gravity, microgravity effects have been studied at the cellular, organism and population levels. The following questions arise. Do any gravity-dependent processes exist in a cell? Is cell adaptation to weightlessness possible; if so, what role may cytoskeleton, the genetic apparatus play in it? What are the consequences of the lack of convection in weightlessness for the performance of morphogenesis? Do the integral characteristics of living beings change in weightlessness? Is there any change in "biological capacity" of space, its resistance to expansion of life? What are the direction and intensity of microgravity action as a factor of natural selection, the driving force of evolution? These problems are discussed from a theoretical point of view, and in the light of results obtained in experiments from aboard biosatellites "Cosmos".
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The monograph has been dedicated to the analysis of structural and functional changes in the central nervous system of the experimental animals exposed to the isolated and combined effects of space flight factors. There have been shown many changes, which took place in the various anatomic-physiological formations of the brain, and evaluated their significance in organism's responses to the effects of ionizing and nonionizing radiation, hyperoxia, hypoxia, accelerations, vibrations and combined effects of some of those factors. The synergistic, antagonistic and cumulative (simple addition) effects of the investigated stressors along with the radiation factor on the CNS have been stated. This review is prescribed for the specialists in space biology, for physiologists, pathophysiologists, biochemists, radiobiologists and physicians.
The authors conducted an experimental study of a radio-modifying effect of exogenous hypoxia on the structures of the blood-brain barrier in rats early after irradiation of the head at a dose of 10 Gy. Histochemical and histological methods were used to assess the status of the endothelium, basal membrane, tissue basophils and astrocytic junction. They indicated change of these structures in irradiation and action of GGS-8 gaseous mixture. Exogenous hypoxia was shown to promote the normalization of transport through the capillary wall as a result of the prevention of injury of the structure and metabolic processes in endothelial cells and basal membrane. The astrocytic junction and, to a certain degree, tissue basophils exhibited synergy in the action of the studied factors.
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Genetic and embryological investigations were continued on the orbital station Salyut-5. The effect of space flight factors on dry Crepis capillaris (L) Wallr seeds and seedlings, dry Arabidopsis thaliana (L) Heynh seeds, Polyporus brumalis Pers. ex. Fries culture as well as on spawn development and fish behaviour was studied. Space flight factors are shown to have adverse effects with respect to some characteristics in seeds and seedlings, and to change the morphology of the fungus. Fishes appear to adapt themselves to weightlessness.
In the experiments on 2200 mice the thresholds of powder density (PD) and time of irradiation were defined, when the death level did not exceed 0.1%. Dependence between the speed ratio of the destruction/regeneration and PD approached the exponential function. The functional dependences obtained quantitatively characterize the adaptive abilities of the mouse organism exposed to microwave irradiation.
The protective effect of cystamine (150 mg kg-1) against genetic damage induced by gamma-radiation in germ cells of the CBA line of mice (at doses of 100, 300 and 600 r) was studied. Cystamine reduced the frequency of dominant lethal mutations in sperms, spermatids and spermatocytes. The amount of protection depended on the radiation dose. After cystamine the lethal effect of radiation on the whole organism was reduced 2-3 times. After transverse acceleration (15 g over 10 min) the protective effect of cystamine against dominant lethal mutations induced by radiation (300 r) decreased on the average by 1/3. The action of transverse acceleration alone somewhat reduced the radiosensitivity of germ cells. The administration of the protector and acceleration did not affect the frequency of reciprocal translocations induced by radiation in spermatogonia.
Lysogenic strains of Escherichia coli were exposed to space conditions aboard the flight of Zond 5 and Zond 7. Space flight factors appeared to affect the state of episome systems of bacteria, as judged by data obtained with F-Lac+ donor cells which also carried genetic markers for threonine and leucine. Observations on phage induction are discussed and compared with results obtained aboard Biosatellite 2. A number of monolayer cultures of human cells (HeLa cells, fibroblasts, and A-1 cells) were repeatedly exposed to the space environment. In one instance, HeLa 19 cells increased in size after exposure to space conditions, a change which appeared to be genetically stable. HeLa 19 cells which were carried on six separate space flights showed a higher viability than corresponding cultures which were exposed only once aboard Zond 5.
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The experiment carried out on the Cosmos 110 biosatellite is a step further in radiobiological investigations performed in outer space and differs appreciably from flight experiments conducted on board the Vostok and Voskhod spacecraft. The difference lies, firstly, in the integral dose of cosmic radiation. According to the onboard dosimeter readings, it was 12 rad at an average dose rate of 500 mrad/day during the biosatellite flight, whereas in previous biological flight experiments, as is well known, the total dose was below 80 mrad (on a five-day flight of Vostok 5) at a dose rate of 80 to 20 mrad/day. Secondly, during the biosatellite mission, cosmic radiation originated not from the primary cosmic radiation as was the case in the Vostok and Voskhod flights but mainly from the Earth's radiation belts. Thirdly, the duration of the Cosmos 110 flight was far longer than that of any previous mission: the effect of weightlessness lasted for about 22 days. The paper presents results of investigations performed on E. coli K-12 lambda lysogenic bacteria, Tradescantia microspores, dry seeds of higher plants, different Chlorella strains and an intact plant of Tradescantia paludosa. The biological effect of space flight factors was evaluated by various physiological, cytogenetic, genetic and microbiological techniques. Similar to previous experiments carried out on board the Vostok 3-6 spacecraft, tests with lysogenic bacteria revealed a statistically significant induction of moderate bacteriophage. The induction value was shown to lag behind the mission duration dependence level. This seems to be related to a change of inducibility properties of lysogenic bacteria and a reduction of the yield range of phages per bacterial cell. Other tests (duration of the latent period, formation pattern of phage components) indicated no significant differences between test and control objects (N.N. Zhukov-Verezhnikov, N.I. Rybakov, V.A. Kozlov et al.). A study of protective properties of chemical compounds of different types in relation to the bacteriophage induction demonstrated that preparations of the aminothiolic group produced a high antimutagenic effect (V.A. Kozlov, N.I. Rybakov et al.). A postflight cytological analysis of Tradescantia paludosa microspores indicated their changes of three types: chromosome aberrations, mitotic disturbances and disorders of growth processes in the cell. Examinations of dry seeds of wheat, barley, pine and other plants, as well as of Allium cepa bulbs, gave evidence of a diverse effect of space flight factors on both physiological processes and hereditary structures of the objects. In some cases an increased percentage of seed germination, stimulation of their growth and a significant increase of aberrations were found. An investigation of the occurrence frequency of visible mutations in reaction cell cultures of different Chlorella strains (LARG-1, LARG-3 and others) showed no significant differences between the test and control material. Some cultures taken under a more detailed study indicated a delay with which cells entered the first sporulation and a greater amount of cells that divided into a lesser than usual number of autospores. In addition, test variants of the strains showed a slightly reduced survival of Chlorella cells. The reduction appeared to be statistically significant for the LARG-3 strain only (E.N. Vaulina et al.). A postflight examination of the appearance of the Tradescantia paludosa plant showed that it retained good turgor; its leaves were dark green and several bright flowers bloomed. No signs of its inhibition or etiolation were noted. As compared to the control, the test plant grew noticeably and the stem became crooked. Certain problems of biological indications of outer space are discussed.
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