Aviakosmicheskaia i ekologicheskaia meditsina = Aerospace and environmental medicine

Publications
The purpose was to investigate cytological and cytogenetic disorders in cornea epithelium and bone marrow cells of mice after different periods since irradiation by protons at an energy of 1000 MeV and gamma doses of 25 to 400 cGy (137Cs). Suppression of the mitotic activity of cells by ionizing radiations was a function of dose value. In addition, the rate of aberrant mitoses was dependent on the type of radiation and time elapsed after exposure. Coeffcients of the relative biological effectiveness of protons with an energy of 1000 MeV in 24, 72 and 120 hrs. after irradiation were calculated based on comparison of doses compromising mitosis in 50% of differentiating cells. For the cornea epithelium cell the coefficients amounted to 1.3; 1.2 and 1.1, respectively; for the bone marrow cells they were 1.2; 1.1 and 0.9, respectively. The fingerprint of the proton biological effect is a higher production of exchange aberrations suggesting more severe damages to the hereditary cells.
 
Dynamics of the gastrointestinal functioning was reconstructed by analysis of the scatological data from volunteered subjects before, on days 16, 35, 45, 60, 90 and after completion of 105-day isolation experiment. The analysis showed that scatological investigations performed in the conditions imitating life in an exploration vehicle environment are instrumental in detecting deviations in the GI function indicative of pancreas excretory and hepar biliary excretion and synthetic hypofunction that can be responsible for intestinal dysfunction. Normalization of scatological parameters following the experiment witnesses to functional genesis of the changes observed during the exploration mission simulation.
 
The investigations of threshold frequency characteristics (TFC) of the visual analyzer and labor productivity were carried out during 105-d isolation of volunteers in an airtight module illuminated by LED lamps adjustable to personal psychophysiological needs. Software and calculation procedure were devised to assist the chromatic TFC-based determination of photometric parameters. Data of analysis of actual mood and vision contrast sensitivity when looking at a three-color image suggested that visual performance could be improved by achieving light color adequacy to TFC of individual vision. The results of experimental investigations showed once again efficiency of the proposed methods and their relevance to the objectives of the extended ground-based experiment simulating an exploration mission to Mars.
 
Automated digital image microscopy was used to evaluate skin microbial populations in 14- and 105-day isolation experiments within the Mars-500 project.
 
Before, in and after the experiment with 105-day isolation and confinement, 6 male volunteers from 25 to 40 years of age rationed NaCl and performed integral impedancimetric, psychological and hormonal investigations. Every 30 days blood collection for hormonal measurements was combined with filling of Cattell's 16 personal factor questionnaire. Parameters of total body fluid, body mass, basic exchange, specific hydration and basic exchange were determined. The results showed that the experimental conditions did not affect significantly body composition, metabolism or neurohumoral regulation; the metabolic variations were largely associated with motivation for and value orientation in accommodation, to the permissible extent, of the controlled diet and work/rest schedule to personal needs. In addition, it was found that evolution of the psychophysiological status of humans in isolation and confinement is governed primnarily by personality characteristics and, to a less degree, specifics and length of exposure to the artificial environment; thus, in the opinion of the volunteers normoxic, normobaric and slightly hypercapnic (0.15-0.65% CO2) atmosphere was comfortable and harmless to health. Analysis of the whole data array verified the expressed interrelation of neuroendocrine and psychophysiological parameters as well as shifts in body basic exchange and mass, salt intake and hydration rate in the conditions of isolation and confinement.
 
Reduced glutathione level and G6FG activity in red blood cells of test subjects in the baseline data collection period, during the experiment, and after its completion 
Relative content of ooHb in blood and Hb affinity for O 2 in test subjects in the baseline data collection period, during the experiment, and after its completion 
Effects of strict 105-d isolation on blood antioxidant status, erythrocyte membrane processes and oxygen-binding properties of hemoglobin were studied in 6 male volunteers (25 to 40 y.o.) in ground-based simulation of a mission to Mars (experiment Mars-105). The parameters were measured using venous blood samples collected during BDC, on days 35, 70 and 105 of the experiment and on days 7 and 14-15 after its completion. Methods of biochemistry (determination of enzyme activity and thin-layer chromatography) and biophysical (laser interference microscopy, Raman spectroscopy) showed changes in relative content of lipid and phospholipid fractions suggesting growth of membrane microviscosity and increase in TBA-AP (active products of lipids peroxidation interacting with thiobarbituric acid). A significant increase in glucose-6-phosphate dehydrogenase and superoxide dismutase activities against reduction of catalase activity points to both reparative processes in erythrocytes and disbalance between the number of evolving active forms of oxygen and antioxidant protection mechanisms in cells. Hemoglobin sensitivity of oxygen and blood level of oxyhemoglobin were found to increase, too. It is presumed that adaptation of organism to stresses experienced during and after the experiment may destroy balance of the antioxidant protection systems which is conducive to oxidation of membrane phospholipids, alteration of their content, increase of membrane microviscosity and eventual failure of the gas-exchange function of erythrocytes.
 
Characteristics of communication, psychooemotional welllbeing, and biochemical state in subjects A, B, D, and E 
Characteristics of communication, psychooemotional welllbeing, and biochemical state in subjects C and F 
Purpose of the study was to assess effects of 105-d isolation on language behavior and psychophysiological status of volunteered subjects. Software NOOJ was used to determine frequency of mentioning in written reports notions falling into the categories of "Needs", "Activity", "Negation" and "Social regulation". Well-being, activity and mood were assessed with the SAN questionnaire and urine cortisol measurement. Correlation of the content-analysis results with phases of adaptation to extended isolation and confinement made it possible to elicit specific features of language behavior of the small group members, at the time of simulated autonomy, specifically. Besides, the computerized content-analysis enabled a quantitative description of communication strategy as a function of psychophysiological adaptation to stressful factors of the simulation experiment.
 
Six male volunteers (aged 25 to 40 years) were subjects in all-round psychophysiological, hormonal and immunological studies before, in and after 105-day isolation and confinement. Blood was drawn and the 16-factorial Cattell personality inventory was filled out every 30 days. Concentrations of blood hormones, neurospecific proteins and cytokines point to a close interrelation between antibody titers to myelin-associated glycoprotein and changes in the parameters of metabolism and reproduction-related hormones, as well as cytokines and individual psychophysiology (extra-introversion, dominance, intropunitiveness, social contact selectivity, etc.), and suggest a minimum risk of demyelinizing neuropathy due to exposure to the conditions of isolation and confinement.
 
The progress of science and technology at the end of the XIXth and first half of the XXth century paved the way to start space exploration by humanity. The flight of Yu. A. Gagarin on April 12, 1961 was one of the history watersheds that had a great many of social implications. Piloted missions to space demonstrated the possibility for humans to adapt to the spaceflight factors which, nonetheless, can provoke various unfavorable reactions, particularly on return to Earth. Step-by-step extension of mission length paralleled enhancement of the methods of monitoring of crew health, life support systems, and development of modalities to maintain crew health and performance. The paper contains brief discussion of data acquired in short- and long-term missions including the 438-d mission of cosmonaut-physician V.V. Polyakov. The final section is devoted to the mainstream problems of future piloted space programs.
 
The structure of vestibular nuclei cells was studied in the brain of Macaca mulatta on return from the 14-d flight on satellite BION-11 and in 2 days of recovery. The monkey suddenly deceased on day 2 since landing because of aspiration asphyxia on completion of biopsy of muscle and bone tissues. Basic shifts in neural cells of the vestibular nuclei were focal tigrolysis and formation of larger clodlets by remains of tigroid. The most pronounced changes occurred to cells in the medial, upper and descending vestibular nuclei. Deiter's lateral vestibular nucleus was least changed. The conclusion has been made that loss of reactivity by vestibular nuclei in microgravity is linked not only with the effects of exterofactors (otolith and labyrinthine receptors) but also with the structural-functional deficiency of cells of vestibular nuclei.
 
The work brought up initial information on the impacts of space flight (SF) on regeneration of nerve tissues in vertebrata. Summarized are data of analysis of the retinal regeneration following section of the ocular nerve and blood vessels in space-flown adult newts (Pleurodeles waltlii). Two weeks in SF were found not to impede the regeneration of retina as its growth was fully dependent on the same cell sources as in the condition of 1 g. In the newts which had been operated 2 wk prior to launch, recovery of retina in SF proceeded more intensively (phases V-VI) compared with the synchronous controls (phase IV). According to the morphometric analysis, differentiation of regenerates' layers in the space animals was also a more rapid process. The proliferative activity of cells in regenerates estimated with the 3H-timidine radioautography turned to be higher, too: the labeled nuclei index in early non-differentiated regenerates was in 1.2 to 1.5 times higher than in the control. Immunohistochemical array with the help of GFAP antibodies performed at the late phases of regeneration revealed an activating effect of SF on the Muller glia cells. These findings indicate that microgravity can stimulate general retinal regeneration and activate regenerate cells, specifically those involved in morphogenesis.
 
The light microscope was used to study serial sections of labyrinths of quail embryos incubated and reared during 12 d orbiting of Cosmos 1129. On recovery the embryos were aged 9, 11.5 and 12 days. No significant deviations in the development of the vestibular apparatus in flight species were noted as compared to the controls. Given this and our experimental data about in-space development of fish and amphibians we may deduce that hypo-g does not exert a noticeable altering effect on the vestibular embryogenesis. Nevertheless, it should be pointed out that in all otolith organs and semicircular channel ampules of the flight embryos cup-form neural endings innervating type I sensory cells were markedly swollen in contrast to the control. Earlier swollen cup-form nerve endings have been found in one adult rat after 7 days of space flight aboard Cosmos 1667. However, exposure in space does not bring about a substantial swelling of bud-like nerve endings which contact type II sensory cells. Thus, a conclusion may be drawn that spaceflight factors are liable to produce shifts in the type I sensory cell--cup-form nerve ending unit but they do not affect type II sensory cell--bud-like nerve ending unit to the extent when effects can be identified by light microscopy.
 
Original data on the peculiarities of adaptation to and functional status of the reproductive system in long-term antiorthostatic hypokinesia (AOH) have been obtained. The studies involved eight healthy female volunteers aged 26-37 years who were exposed to the head-down tilt (-6 degrees) for 120 days. The test subjects were divided into 2 groups of 4 persons each. In Group A, the countermeasures, i.e. physical exercise and pharmacological means, were used. In Group B, at no time did the test subjects use the countermeasures throughout the 120-day AOH. With and without the countermeasures, hypokinesia was found to impact the female reproductive system developing clinical symptoms of deficiency of the menstrual lutein phase and giving rise to small inclusions of functional fluids in the ovaries. Within 6 months after AOH, the ovarial function of the test subjects was fully recovered which may be indicative of the functional character of changes. These changes can be explained by dissociation of the functional relations in the hypothalamo-hypophyseal-ovarial system manifested by increases in the plasmic concentrations of luteinizing hormone (LH) against normal levels of follicle-stimulating hormone (FSH) and prolactin, and moderately increased levels of testosterone, relative hyperestrogenemia and hypoprogesteronemia. These clinical and hormonal developments are contrary to the observations usually made in various models of stress. Similarity of the hormonal profiles under hypokinesia and long-term immersion of female swimmers may be ascribed to common mechanisms underlying the disturbance of the reproductive function.
 
Time dynamics of variations in the spinal reflex mechanisms was evaluated during 120-d HDT (-6 degrees). Already within the first days in HDT the knee and Achilles reflexes were noted to sharply become easy to fulfil, the conclusion made from a significant drop of thresholds, an appreciable rise of amplitudes of reflex responses and an expansion of the range of stimulations. However, dynamics of these variations was diverse. The abrupt drop of reflex thresholds determined already on HDT day 2 was persistent throughout the experiment, whereas maximal rise of the tendon reflex amplitude was seen on the initial phase of HDT (days 15-30). Later on, a clear-cut downward trend of the electromyographic amplitude was observed. The experimental data suggest that hyperreflexia during HDT is one of the manifestations of partial deafferentation of the motoneuron pool due to diminution of the proprioceptive afflux. At the same time, hyperactivity of the reflex mechanisms is masked by the peripheral muscular effects of the same factor, i.e. HDT.
 
This paper presents an information on the goals, tasks and protocols of a 120-day head-down tilted bedrest study with participation of eight female subjects. It describes the use of various methods of research and different countermeasures.
 
The goal of the work was to study female tolerance of g-loads before and after simulated weightlessness, and evaluate the effectiveness of countermeasures and anti-g means proposed for space flight. Centrifuge with a 7.25 m arm was used for 29 runs of 8 female subjects. The subjects were exposed to the transverse loads (+GX) at 8.2 g on a special regimen with the total run time of 9 min to simulate the ballistic descent from orbit in a SOYUZ-TM vehicle. Baseline tolerance of the females to transverse loads up to +8GX was good and satisfactory. Following 120 days of bed rest without the countermeasures or the anti-g suit g-tolerance was significantly lowered as evidenced by visual disorders in 67% of cases and exaggerated, if compared with the pre-hypokinesia levels, heart and respiration rates, i.e. 20% and 23.5%, respectively. The countermeasures and anti-g suit Centaur maintained g-tolerance at essentially the baseline level and precluded visual disorders. Results of the study speak in favor of the countermeasures and anti-g means used by the females in simulated long-duration weightlessness which can be recommended for the final phase of extended space mission.
 
The state of bone tissue has been studied in 8 women subjected to a 120-day HDT. Four test subjects (Group A) performed physical exercises during the experiment. Mineral content (MC) in bone tissue and mineral density of the bones (MD) were determined with the help of dichromatic x-ray bone densitometer HOLOGIC QDR--100/W. The velocity of propagation of ultrasound in the shin bone was also determined. It is found that the hypokinesia-associated losses of bone mass in the lower segments of the skeleton of women were insignificant. In the control group (Group B, non-exercising subjects), there markedly increased MC in the bones of the upper body and there were the slight signs of hypomineralization of the segments of the lower body as well as the significant (in 2 test subjects) decrease of MC in the pelvic bones in the recovery period to the level lower than at the beginning of the experiment. In group A, the increase of MC in the upper skeleton was expressed to a lesser degree. At the recovery period the all changes were practically neutralized and there were no signs of bone mass loss. The velocity of ultrasound by the Day 90 of the experiment had the marked tendency for a decrease in group A persisting up to the end of experiment while in the group B its changes were oppositely directed. Within 2 months after the experiment in the majority of women the tendency for recovery of the initial state both by the absolute values of ultrasound velocity and by the profile of curves of their distribution over the anterior surface of the shinbone was noted. The results are discussed in comparison with findings obtained in the experiments with long-term hypokinesia in men and in the space missions.
 
Investigations of eight healthy female volunteers aged 26-37 in 120-days antiorthostatic hypokinesia (AOH, -5 degrees) gave original data about peculiarities of adaptation and functional state of female thyroid and the thyreotrophic activity of adenohypophysis. The test-subjects were divided into two equal groups. Group 1 administered a set of countermeasures including exercise and pharmacy. In the other group, no health control was used. By days 90-100 in AOH thyroid glands of the females were slightly more compact but remained diffuse. Thyroid sizes were not altered. Chemical/biochemical examination did not elicit any noteworthy shifts in the thyreotrophic activity of hypophysis or thyroid function in the bedrested females. The countermeasures did not enhance the thyroid function. Results of the investigation point to the completion of thyroid adaptation of females by days 90-100 in AOH.
 
The system of posture regulation was evaluated during 120-d head-down bedrest (-6 degrees). Functioning of the system was evaluated by the characteristics of corrective posture responses to pushes in the chest breaking the body equilibrium. Analyzed were parameters of amplitude and time of corrective responses, and strength and range of stimulus intensity. Results of the investigation showed that HD bedrest materially disturbs vertical stability and impairs effectiveness of the posture corrective mechanisms. Based on the data of this investigation and findings of previous efforts we can confidently distinguish two phases in development of disturbances in vertical stability during long-term HD bedrest associated with different leading mechanisms. On the first phase (15-30-d into the experiment), the principle posture problems are reduced tone of the anti-gravity musculature. On the second phase, particularly beginning on day 60, muscular atrophy processes become leading factors of postural disturbances. Apparently, these mechanisms, along with changed vestibular input, considerably impact vertical stability, especially after extended space mission.
 
Cytogenetic assay of the chromosomal apparatus of human blood lymphocytes was carried out after in vitro irradiation by heavy charged particles with high LET values. Blood plasm samples enriched with lymphocytes were irradiated by accelerated ions of carbon 12C (290 MeV/nucleon and LET = 70 keV/microm), neon 20Ne (400 MeV/nucleon and LET = 70 keV/microm), and iron 56Fe (500 MeV/nucleon and LET = 200 keV/microm) in the dose range from 0.25 to 1 Gy. Rate of chromosome aberrations showed a linear dependence on doses from the densely ionizing radiations with high LET values. Frequency of dicentrics and centric rings in human lymphocytes irradiated by 12C with the energy of 290 MeV/nucleon was maximal at 1 Gy (p < 0.05) relative to the other heavy particles. It was found that relative biological effectiveness of heavy nuclei is several times higher than of 60Co gamma-radiation throughout the range of doses in this investigation.
 
After a 13-day space mission, in the rats flown on Cosmos-1887 biosatellite the parameters of lipid peroxidation and antioxidant defense system--the contents of diene conjugates, malonic dialdehyde, Schiff bases, tocopherol, total antioxidant activity (in blood plasma only), antioxidant enzyme activity (in tissues only)--superoxide dismutase, catalase, glutathio peroxidase, glutathio reductase have been measured in the blood plasma, myocardium, skeletal muscles and liver. The liver level of diene conjugates, Schiff bases and tocopherol decreased, and an activity of superoxide dismutase and catalase increased. In the skeletal muscles there was an elevation of diene conjugate contents followed by the decreases in malonic dialdehyde and superoxide dismutase activity. In rat myocardium, superoxide dismutase activity and tocopherol levels increased significantly. In the blood plasma the levels of tocopherol, malonic dialdehyde and total antioxidant activity were elevated. It is concluded that the observed changes in lipid peroxidation developed probably in response to an effect of the last dynamic stage of space flight and during re-adapting to the Earth environments.
 
There present the investigative findings of the dynamics of psycho-physiological and biomedical responses of the test subjects during simulated emergencies at different stages of adaptation to 135-day isolation in the Mir orbital station mock-up. Ehe main operating factor of an emergency was the 2-day sleep deprivation in combination with the continuous complex and intensive operator work which included the elements of the professional activity of the cosmonauts, among them the simulation of the regular and emergency docking of the spacecraft. By and large the observed physiological responses were characterized by moderate degree of manifestation, they were of functional character and were adequate for the investigated experimental conditions. The impaired quality of performing the applied psychophysiological tests and what is especially important the operations simulating the cosmonauts, professional activity in the extreme emergency conditions is noteworthy. Judging from some indicators the manifestation was dictated by the duration of operator isolation in the Mir orbital station mock-up and by the duration of a contingency simulation. In the degree of manifestation and in the time of development some changes in the state and working capacity of the operators were characterized by the individual differences.
 
The investigation was performed with three test-subjects who were locked in a chamber with simulated spaceflight environment for 135 days. Samples of venous plasma were collected to determine concentrations of total protein, total cholesterol (TCh), cholesterol of high density lipoproteins (HDLP), alpha 1-inhibitor of proteolysis (alpha 1-Pl), alpha 2-microglobulin (alpha 2 M), and haptoglobin (Hp). Concentrations of cholesterol of low density lipoproteins (Ch LDLP) and HDLP-LDLP ratio were calculated. Relative content of electrophoretic fractions of alpha 1- and alpha 2-globulins and a qualitative pattern of electrophoretic separation of lipoproteins were also determined. Data from the investigation showed significant decreases in alpha 1-Pl, alpha 2-M, Hp, and the alpha 2-globulin fraction that could be consequent to suppression of protein synthesis in the liver. Considering that at some points in the investigation concentrations of proteolysis-inhibiting and regulating alpha 1-Pl and alpha 2-M dropped to or went beyond the bottom margin of the norm, these effects have physiological implications. On days 2 and 7 after exit from the chamber, a weak acute-phase reaction was apparently linked with the emotional stress. Two test-subjects had chronologically differing periods of elevated TCh and Ch HDLP. Yet, the HDLP-LDLP ratios have never left boundaries of the physiological norm.
 
Ultrastructure, tissue respiration and oxidative phosphorilation were studies in the myocardium of animals after chronic natural irradiation by 137Cs in quantities that can in reality threaten population of radionuclide-polluted regions. Decline in the respiratory activity of the myocardium and ultrastructural disorders can be attributed to the effects of ions of radioactive Cs which is also a potassium antagonist. A hypothesis has been put forward according to which cesium blocks potassium channels in mitochondria and thus changes the volume and configuration of internal mitochondrial membranes, and impacts the respiratory processes. In the opinion of the authors, these changes characterize the mitochondrial phase of apoptosis which, in the event of chronic exposure to radionuclides, is a compensatory-adaptive mechanism eliminating the least immutable subpopulation of cardiomyocites.
 
Specificity of the use of ballistocardiography (BCG) in space flight is considered. In particular, the contactless method makes it possible to continue recording during the night hours and study the ultradian rhythms reflective of the state of higher autonomous centers. As was stated, on months 7 to 8 of the mission by cosmonaut-physician Polyakov the BCG amplitude rose in concert with activation of the higher autonomous centers that were apparently involved in maintaining the established cardiovascular homeostasis. By months 11 to 13 on mission, the BCG amplitude decline resulted in an increase in the SCG/BCG index representing the amount of myocardium energy spent on blood transport.
 
Effects of 14-d suspension on the processes of rats' nervous cells conjugation in the brain cognitive cortex were studied. Signs of cognitive functions degradation and decrease of the number of conjugated nervous cells were found in the experimental group after suspension. This evidence are qualified as a negative effect of suspension on memory and physiological regeneration of neurons. © State Research Center RF - Institute of Biomedical Problems Russian Academy of Sciences, 2008 All rights reserved.
 
The effect of a 2-week space mission on the geometry parameters of giant multipolar neurons of the brain stem reticular formation in the rats flown on board Cosmos-1887 and -2044 are studied. Compensation for a deficiency of vestibular informations from the trigeminal nerve system at the cost of an decreased length of the dendrites oriented toward primary sensory nucleus and from the vestibular system through an increase in the length of the vestibular sensory nuclei-oriented dendrites is discussed.
 
After 14-day space flight of rats onboard Cosmos 2044 in their blood plasma, homogenates of liver, skeletal muscles and myocardium there were determined the parameters of peroxide oxidation of lipids (POL) and system of antioxidant defense: content of dienic conjugates (DC), malonic dialdehyde (MDA), schiff bases (SB), tocopherol (TF), total antioxidative activity (AOA, only in plasma), activity of antioxidative enzymes (only in tissues) superoxide (SOD), catalase, glutathione-peroxidase (GP), glutathione-reductase (GR). In the animal liver there was a decrease in SB content and an increase of SOD, catalase and GP activities. Skeletal muscles exhibited a reduced SB concentration. In myocardium there was a reduction of DC and SB levels, activity of GR with an increase of TF concentration, activity of SOD and catalase. In the blood plasma there occurred a decline of SB and TF contents and an elevation of MDA and total AOA concentrations. The authors drew a conclusion about a compensated process of POL in the tested animals and about the relation of the observed changes with body response to the final phase of the space mission and acute gravitational stress during a readaptation to the Earth environments. On the basis of the analysis of similar data from shorter-duration space experiments, the noted changes in the parameters of the system of POL and antioxidant defense are considered a universal response which does not directly depend on duration of the orbital phase of a space mission.
 
Cell breathing and relative desmin content were investigated in m. soleus fibers of rats after 3 and 7 days of recovery from 14-day suspension according to the Morey - Holton modification of the Ilyin - Novikov procedure. The cell breathing parameters were determined with the help of polarography; desmin content was measured using the western-blot technique. The results evidence that cell breathing intensity subsided during 14 days of gravitational unloading, reached minimum after 3 days of recovery and regained baseline values after 7 days of recovery. Post suspension desmin content did not differ from control values, made a significant drop in 3 days and returned to baseline values in 7 days of recovery. These data suggest an interdependence between cell breathing and desmin content in m. soleus fibers of rats as during gravitation unloading, so in the period of recovery.
 
Histological, histochemical and histomorphometric methods have been used to study an effect of a 14-day head-down suspension on healing the fractured fibular diaphysis in the rats traumatized immediately after suspension. The study of the fibulae on Days 11 and 17 following an operative fracture indicated that both in control and experimental rats the ends of fractured bones were tightly interconnected by the calluses. A comparative study of the calluses and their structural components as well as detailed investigation of histological structure of calluses on the 11th and 17th post-traumatic days did not reveal significant differences between control and experimental animals. Furthermore, the rate of cartilage replacement by spongy bone tissue in calluses of experimental animals was even somewhat higher than that in control rats. Thus the data obtained give ground to believe that in a readaptation period after 14-day suspension resulting in the osteoporotic changes of weight-bearing bones a repair process in the bones is rapidly normalized and in some parameters exceeds it in control animals.
 
Longevity of space stations is dependent on efficiency and robustness of the life support systems. The article describes the principle of operation of air decontamination system Potok 150MK intended for providing microbial safety of the orbital station environment. High quality of air disinfection and decontamination has been demonstrated aboard SS Mir and the International space station.
 
Investigations into g-tolerance of female cosmonauts during descent in space flights of varying duration are topical for the present day, as there are little data on this issue. Tolerance of +Gz-loads during descent was analyzed based on the data about 4 female cosmonauts in 5 space flights. The space flights were conventionally divided into short- (8-16 days) and long-term (169 days). In two space flights (16 and 169-d long), tubeless anti-g suit Centaur was warn during descent. In these space flights, g-tolerance of females was quite satisfactory advocating for the possibility for women to fly to space without any constraints. When the anti-g suit was not used, female physiological systems were stressed heavier than male. The spacesuit smoothed away this difference. Our results evidence a distinct positive effect of wearing the anti-g suit by female cosmonauts during descent as it reduces stress to their physiological systems.
 
Methods of quantitative morphological and histochemical assay were used to study effects of 9-month electrical exposure (f = 17 kHz, E = 100 kW/m2 for 1 or 4 hrs, 5 d/w) on testis and testis appendages in mice. Exposure in electromagnetic field gave rise to desquamation of spermatogenic epithelial layers in the seminiferous tubes, reduction of the number of testosterone-producing cells, microcirculatory changes, metabolic rearrangements, principally compensatory by nature and aimed to maintain spermatogenesis and steroidogenesis. Results of the experiment suggest accelerated reproductive ageing.
 
For assessing health risk, the measurement of physical dose received during a space mission, as well as the LETs, energies and charges of particles is important. It is also important to obtain quantitative information regarding the effectiveness of space radiation in causing damage to critical biological targets, e.g., chromosomes, since at present the estimated uncertainty of biological effects of space radiation is more than a factor of two. Such large uncertainty makes accurate health risk assessment very difficult. For this very reason, a study on cytogenetic effects of space radiation in human lymphocytes was proposed and done for MIR-18 mission. This study used FISH technique to score chromosomal translocations and C-banding method to determine dicentrics. Growth kinetics of cells and SCE were examined to ensure that chromosomal aberrations were scored in first mitosis and were induced not by chemical mutagens. Our results showed that chromosomal aberration frequency of post-flight samples was significantly higher than that of pre-flight ones and that SCE frequency was similar between pre- and post-flight samples. Based on a dose-response curve of preflight samples exposed to gamma rays, the absorbed dose received by crews during the mission was estimated to be about 14.5 cSv. Because the absorbed dose measured by physical dosimeters is 4.16 cGy for the entire mission, the RBE is about 3.5.
 
Effects of rectified water with low content of heavy stable isotopes of hydrogen (deuterium) and oxygen (18O) on radiation damage were studied in senior males of the Balb/c mice. The animals were irradiated by 60Co in unit PX-gamma-30 at a dose of 0.50 Gy. Dose rate was equal to 0.32 cGy/min. It was shown that rectified water had a positive effect on recovery of radiation damage such as impairment of immune organs (thymus and spleen), peripheral blood and marrow cells.
 
The paper features the history of the Institute of Biomedical Problems (IBMP), the Russian leading institution in space biology and medicine, and the advances achieved by researchers over 35 years since its foundation. Special attention is devoted to the contribution of the Institute to the establishment of international co-operation in human space flight and space life sciences. Future of the space life sciences and humans in space is outlined.
 
In 1985, Rockwell International (now Boeing--North American) completed the Space Station Crew Safety Alternatives Study for NASA. This five-volume study identified a wide range of potential safety threats and hazards that the crew might encounter on the future International Space Station. These threats included fire, explosion, collision, decompression, contamination, and radiation, among many others. One volume focused on the human factors aspects of safety, featuring the Crew Safety-Human Factors Interaction Model. In this model, a stressor (such as one of the threats) can lead to degraded performance, which can contribute to human error, unless appropriate and effective countermeasures are available to the crew. In 1986, the Soviet Union launched the Mir Space Station, the "second generation" that followed the Salyut series of space stations. The Mir was designed for a five-year life on orbit. It remained in use for fourteen years. During the first ten years, it performed well, with few safety issues. However, during the last four years, the aging station--operating at more than two times beyond its design lifetime--encountered a variety of safety hazards and human factors issues. Despite these often serious problems, the Mir crews always found a way to save the station, and no crew member was seriously injured or killed. This paper evaluates the safety record on Mir, and compares it to the NASA-Rockwell study, that was contemporaneous with the construction and launch of Mir. This comparison and analysis can provide a foundation for future space crew safety and related human factors support.
 
This paper is dedicated to the analysis of the radiation situation onboard Mir station over a period of 1986-1994, there examined the main cosmophysics parameters and indices of the solar activity as well as the variations of the parameters of the earth's magnetic field and their association with the changes in the power of absorbed dose onboard the station. There noted the high levels of radiation exposure to the cosmonauts under terrestrial conditions when carrying out the roentgeno-radiologic examinations and procedures comparable or exceeding the absorbed doses during the flights. For revealing the regular associations of the radiation situation onboard the station with the parameters of solar activity there has been analyzed the time changes of average monthly values of dose power since the beginning of station functioning in 1986 until returning the fifteenth expedition to Earth. From the analyses of the results it might be assumed that the best statistical associations of average monthly power of the absorbed dose are found with the streams of protons of GCR. Wolff numbers and background stream of the radio emission of the Sun which reflects the existence of the radiation situation upon the phase of solar activity cycle. From this paper it transpires that calculating the dose loads during the period of the extreme phases of solar activity, it is possible to make between them the interpolations of time dependence by analogy with the dynamics in time of the background streams of GCR or Wolff numbers.
 
Analysis of radiation dynamics on board the orbital complex MIR in the period of 1994 through to 1996 overlapping minimum of the 22nd solar cycle (SC) was performed. Radiation parameters in the working compartments during eight MIR missions (MIR 15-22) were evaluated. According to the solar dynamics during minimal activity with the lowest meanings of Wolf numbers (< 20), the daily average dose rate on MIR reached its peak over the whole 22nd SC and by a factor of more than three exceeded meanings typical for solar maximum. A statistical method was used to compute correlation coefficients and set up an equation of linear regression of the absorbed dose with cosmophysical parameters of the SC minimum. Meanings of the correlation coefficients for SC minimum were substantially lower as compared with SC maximum, that is there was no distinct correlation between dose rate and the parameters under study. Radiation doses to cosmonauts violated the admissible radiation limits for ground exposures but not radiation limits established for manned space missions. Reduction of dose loading on cosmonauts during SC minimum can be achieved by planning shorter missions or utilization of a program of radiation protection for traverse of SAA ERB.
 
Investigations with Macaca mulatta of 4-5 yrs. of age with the body mass of 4.5-6.5 kg showed that 10 days of tilting with the head end at .5 degrees reduced body temperature but not levels of interleukine-1beta and interleukine-6 in blood plasma. On the next days after return of animals to cages IL-6 was found to increase sharply in more than 10 times. On subsequent 4 days both IL -1beta and IL-6 were within the normal range.
 
Characteristics of spermatogenesis, morphometric changes in the Leydig's and Sertoli's cells, and fertility of albino rats exposed to various doses of 2.4-D were investigated. Chronic injection of the herbicide led to transitional sterility against pronounced disorders of spermatogenesis, hyperplasia of sertolicytes and predominance of low-active forms of the Leydig's cells. An assumption concerning possible role of altered gonadostat in genesis of the reproductive disorders is offered.
 
Dynamics of the ISS RS radiation environment was studied using the data of daily (operative) monitoring and personal dose measurements during 11 increments in the period between August 1, 2000 and October 28, 2005 overlapping the maximum phase of the 23rd solar cycle. It was shown that personal absorbed doses varied within the range of measurements of dual wavelength radiometer R-16, a component of the ISS radiation monitoring system. Power of the absorbed doses fell in the range of 0.017 to 0.02 cGy/day and was solar-dependent.
 
The geometrical model of suited cosmonaut's phantom was used in mathematical modeling of EVAs performed by cosmonauts with consideration of changes in the ISS Russian segment configuration during 2008-2009 and the dependence of space radiation absorbed dose on EVA scene. Influence of spatial position of cosmonaut on absorbed dose value was evaluated with the EVA dosimeter model reproducing the actually determined weight and dimension. Calculated absorbed dose values are in good agreement with experimental data. Absorbed doses imparted to body organs (skin, lens, hemopoietic system, gastrointestinal tract, central nervous system, gonads) were determined for specific EVA events.
 
Space experiment with Chlamydomonas reinhardtii demonstrated that the microgravity effects were noted in Chlamydomonas at both cellular and population levels: in space the cell size is increased, stage of active growth of the culture is extended, it contains the juvenile vegetative motile cells in greater quantities. Ultrastructural analysis indicated that in microgravity the changes in shape, structure and distribution of intracellular organelles and in volume ratio of organelles and cytoplasma are absent. Chlamydomonas data are in line with the results of the Infusoria and Chlorella experiments.
 
This paper presents the results of evaluation of the biological effect induced by cosmic rays in embryo tissues of Arabidopsis thaliana seeds exposed in Biocosmos-9 (BION-9). The experiment was carried out in cooperation with the Botanical Institute and the Institute of nuclear Physics of J.W. Goethe University, Frankfurt-am-Main, Germany using the Biostack system. The data ere obtained in Moscow 4 months and 3 years after the flight. It was shown that in Arabidopsis seeds exposed outside BION-9 the effect evaluated by all the biological criteria used was higher than in seeds exposed inside BION-9. In some characters the effect in the latter did not differ from that in control seeds but in others (black spots, tumors, mutations) it was higher. In tetraploid line the per cent of plants with tumors was higher than in diploid line. The differences observed can be explained by the fact that the total dose of irradiation and the flow of heavy ions were significantly higher outside than inside BION-9. The data obtained cooperatively with German colleagues showed that the seeds hit by heavy ion could not practically develop in the normal way. It was noted that after prolonged storage of seeds after the flight the biological effect in control seeds and in seeds exposed inside BION-9 did not change, and increased in seeds exposed outside BION-9.
 
Top-cited authors
Vs Schneider
  • NASA Johnson Space Center
Alla Vinokhodova
  • Институт медико-биологических проблем (ИМБП)
Igor Podolskiy
  • Институт медико-биологических проблем (ИМБП)
Ludmila B Buravkova
  • Institute of Biomedical Problems Russian Academy of Sciences (IBMP RAS) Институт медико-биологических проблем (ИМБП)
Vadim Gushin
  • Институт медико-биологических проблем (ИМБП)