[MINERAL BONE DENSITY AND BODY COMPOSITION IN PARTICIPANTS IN EXPERIMENT MARS-500].

Investigations of the bone system and body composition in Mars-500 test-subjects (prior to and on completion of the experiment) involved dual-energy X-ray absorptiometry (DXA) using the HOLOGIC Delphy densitometer and the protocol performed to examine cosmonauts. Bone density of lumber vertebrae and femoral proximal epiphysis, and body composition were measured. Reliable changes in vertebral density found in 3 test-subjects displayed different trends from +2.6 to -2.4%. At the same time, the experiment decreased significantly mineral density of the femoral proximal epiphysis, including the neck, in all test-subjects. Four test-subjects had cranial mineralization increased by 5-9%, same as in some cosmonauts after space flight. All tests-subjects incurred adipose loss from 2 to 7 kg; one test-subject lost 20 kg, i.e. his adipose mass became three times less. Changes in lean mass (1-3 kg) typically were negative; as for changes in lean mass of extremities, they could be linked with adherence to one or another type of physical activity. Therefore, extended exposure to confinement may affect mineralization of some parts of the skeleton. Unlike real space missions and long-term bedrest studies conducted at the Institute of Biomedical Problems in the past, Mars-500 did not cause clinically significant mineral losses (osteoporosis, osteopenia), probably because of the absence of effects of microgravity.

[Interrelation of dynamics of blood lipids and bone mineral density in humans during 370-day bed rest].

Comparison of bone mineral density and fatty-acid blood content in 9 human subjects exposed to 370-d bed rest revealed correlation of the loss in femoral neck density with parameters of lipid exchange. On day-46 of BR, the absolute lipids content in erythrocyte membranes and blood serum decreased considerably (1.5-2 times) when compared with baseline data. At the end of the experiment, lipids content in serum, on the contrary, surpassed baseline values 2-3 times: however, it remained lowered in erythrocyte membranes of the control group till day-280 of BR. Arachidonic acid correlated with prostaglandins PGE2 and PGF2alpha involved in regulation of osteoclasts and osteoblasts activities. Correlation of decreases in femoral neck density and unsaturated fatty acids in blood serum and erythrocyte membranes varied with the human subjects.

[Changes in lipid composition of human plasma and erythrocyte membranes due to sodium hydroxybutyrate and normobaric hyperoxia during bed rest].

Gas chromatography was employed to study effects of sodium hydroxybutyrate (GHBA) and normobaric hyperoxia on the fatty-acid composition of total lipids of blood plasma and erythrocyte membranes in 5 normal male volunteers in the baseline data collection period and during 14-d bed rest. Both in plasma and erythrocyte membranes saturated palmitic acid was found increased and polyunsaturated linoleic acid and arachidonic acid reduced.

[The combined action of octafluoropropane and bipolar ionized air].

An experiment with Wistar male rats was to look into the action of octafluoropropane (OFP, of 50 microg/m(3)) combined with bipolar ionized air (BIA) at a concentration of light air ions of 60,000 para-air in cm(3). The chamber experiment was 43 days long. Intoxication by OFP reduced body mass, as well as the erythrocyte count and hemoglobin level in peripheral blood. As for BIA, it appeared to bring these indices back to their normal values. Erythrocyte metabolism underwent phase-by-phase shifts; but breathing BIA mitigated these shifts markedly. As regards to erythrocyte metabolism in intoxicated animals, BIA had a compensatory effect Changes in the biochemical profile of blood plasma make us think, that BIA counteracts the OFP damaging action on the myocardium and, at the same time, aggravates impairment of metabolism in the liver and, probably, kidney. Variations in the spectrum and total content of higher fatty acids in the lung in the experiment were more pronounced in the event of exposure to OFP+BIA than to OFP alone. Also, the combined exposure increased the level of laurinic acid. Histological investigations of the liver, spleen, myocardium, trachea and the lung attested to the dystrophic damage of the liver, spleen plethora and reticular hyperplasia, and slight cloudy swelling of the myocardium attributed to OFP. After 14 days since the end of the experiment, histological changes were much less dramatic; in 39 days after the experiment all the changes were gone with the exception of weak emphysematosis. BIA had no effect on animals in the absence of OFP; neither was there any significant difference between control (intact) animals and those who breathed BIA in laboratory. To conclude, 50 microg/m(3) of OFP which falls far short of the existing maximum permissible levels, a strong toxic action on animals. Aside from mitigation of the OFP toxic action on erythrocytes and myocardium, BIA, when breathed with a long time, aggravated the metabolic disorders in the liver and lung provoked by OFP.

[Assessment of the effects of sodium oxybutyrate and normal pressure hyperoxia on human blood plasma and erythrocyte membrane lipids during antiorthostatic hypokinesia].

Benefits from an antihypoxic agent (sodium oxibutyrate) and normal pressure hyperoxia to the lipid composition of erythrocyte membranes and blood plasma were assessed in 9 subjects on the thirtieth day of head-down tilting at -8(0). The greatest variations in HDT occurred in polyunsaturated fatty acids in erythrocyte membranes. After infusion of sodium oxibutyrate a marked reduction in polyunsaturated fatty acids was mainly in consequence of expressed decreases in linoleic and, particularly, arachidonic acids. However, ensuing hyperoxic treatment led to their steady rise. Sequential sodium oxibutyrate infusion to the tilted subjects breathing air and then exposed to normal pressure hyperoxia seemed to have compensated, as judged by the fatty acids in erythrocyte membranes, for the activity of free radical oxidation in hypoperfusated regional tissues.

[The relationship of changes in blood fatty acids and calcium during 370-day head-down bed rest].

Serum calcium and serum and erythrocyte higher fatty acids (HFA) in 8 male subjects in a 370-d head-down bed rest experiment were different in group-A (applying preventive physical training and pharmacy) and group-B (control). On day 46 of the experiment, HFA content in all lipid fractions decreased sharply in both groups; however, HFA level in serum exceeded baseline values in 2-6 times and remained low in erythrocytes. Difference between the groups became appreciable on HDT day 110.

[Fatty acid composition of the lipids in human blood plasma and erythrocyte membranes during simulation of extravehicular activities of cosmonauts]. / Zhirnokislotnyi sostav lipidov plazmy krovi i membran éritrotsitov u cheloveka v usloviiakh, imitiruiushchikh vnekorabel'nuiu deiatel'nost' kosmonavtov.

Dynamics of the lipoacidic content of total plasma lipids and erythtocyte membranes was studied in 32 experiments with ten apparently healthy male subjects aged 27 to 41 years who were exposed to repeated decompression from the normal ground down to 40-35 kPa. For two hours of exposure to lowered pressure the subjects were breathing pure oxygen in mask and performing incremental physical work mimicking loading of the upper extremities of cosmonauts doing extravehicular activities (EVA) at the energy cost of 3 kcal/min. Decompression sessions were repeated with intervals from 3 to 5 days. In seven experiments, the subjects developed symptoms of the decompression sickness (DCS). Penetration of gas bubbles (GB) into the pulmonary artery was registered in 27 cases (84.4%). In 24 cases maximal intensity of the US signals from GB reached 3 to 4 Spencer's points. No changes in the lipidoacidic content of blood plasma or erythrocyte membranes were determined following the first exposure to decompression. BY the onset of repeated decompression, total number of lipids in erythrocyte membranes decreased from 54.6 to 40.4 mg% in the group of subjects who had not displayed DCS symptoms (n = 5) and from 51.2 to 35.2 mg% (p < 0.05) in the group of subjects with DCS symptoms (n = 5). In the subjects with DCS, polyunsaturated linoleic acid (18:2) tended to decrease against the upward trend of saturated fatty acids (16:0, 18:0). In these subjects, arachidonic acid in erythrocyte membranes (20:4) decreased following each decompression exposure and significantly increased (p < 0.05) in-between. In both groups, blood plasma showed slight fluctuations in the lipoacidic contents. These data suggest that exposure to the variety of the EVA-simulating factors may entail quite distinct but reversible modifications in the lipid metabolism in blood and the structural/functional state of erythrocyte membranes. The most marked alterations were observed in the subjects with the DCS symptoms during high intensity of US signals from GB in the venous blood flow.

Fatty acid composition of plasma lipids and erythrocyte membranes during simulated extravehicular activity.

Ten subjects (from 27 to 41 years) have been participated in 32 experiments. They were decompressed from ground level to 40-35 kPa in altitude chamber when breathed 100% oxygen by mask and performed repeated cycles of exercises (3.0 Kcal/min). The intervals between decompressions were 3-5 days. Plasma lipid and erythrocyte membrane fatty acid composition was evaluated in the fasting venous blood before and immediately after hypobaric exposure. There were 7 cases decompression sickness (DCS). Venous gas bubbles (GB) were detected in 27 cases (84.4%). Any significant changes in the fatty acid composition of erythrocyte membranes and plasma didn't practically induce after the first decompression. However, by the beginning of the second decompression the total lipid level in erythrocyte membranes decreased from 54.6 mg% to 40.4 mg% in group with DCS symptoms and from 51.2 mg% to 35.2 mg% (p<0.05) without DCS symptoms. In group with DCS symptoms a tendency to increased level of saturated fatty acids in erythrocyte membranes (16:0, 18:0), the level of the polyunsaturated linoleic fatty acid (18:2) and arachidonic acid (20:4) tended to be decreased by the beginning of the second decompression. Insignificant changes in blood plasma fatty acid composition was observed in both groups. The obtained biochemical data that indicated the simulated extravehicular activity (EVA) condition is accompanied by the certain changes in the blood lipid metabolism, structural and functional state of erythrocyte membranes, which are reversible. The most pronounced changes are found in subjects with DCS symptoms.

[Dynamics of prostaglandin contents and several indicators of lipid metabolism in man exposed to prolonged hypokinesis]. / Dinamika soderzhaniia prostaglandinov i nekotorykh pokazatelei lipidnogo obmena u cheloveka v usloviiakh dlitel'noi gipokinezii.

Nine healthy test subjects divided into Group A and Group B were bed rested (with the head down at -5 degrees) for 370 days. Group A subjects exercised from the beginning of the study while Group B subjects began exercising only 120 days after. During the study prostaglandins PGE and PGF2 alpha in serum and fatty acids in serum and erythrocyte membranes were measured. The lipid concentration in erythrocyte membranes decreased during the study and returned to the norm at a final stage and after the study. However, changes in higher fatty acids and a dramatic decline of prostaglandin give evidence for serious alterations of lipid metabolism at the cellular level.

[Effect of prolonged storage on various indices of the fatty components of freeze-dried products]. / Vliianie dlitel'nogo khraneniia na nekotorye pokazateli zhirovoi komponenty produktov sublimatsionnoi sushki.

The effect of prolonged storage at the temperature 20 +/- 5 degrees C and relative humidity 70-80% on the freeze-dried food products packed in a three-layer polymer was investigated. The organoleptic parameters, fat content and fat physicochemical properties were determined in the freshly prepared foods and foods stored for 6, 10 and 14 months. The fat component of cereals and vegetables was found to change during storage: the acid and peroxide numbers increased, products of secondary oxidation accumulated, and non-saturated fatty acids decreased. Among the foodstuffs examined the buckwheat cereal and mashed potatoes proved to be most stable and edible after 14 months of storage.

[Evaluation of human skin function in a sealed room by a chromatographic method]. / Otsenka sostoianiia kozhi cheloveka v germopomeshchenii s pomoshch'iu khromatograficheskogo metoda.

Gas-liquid chromatogrophy was used to study the skin and sebum cutaneum of 6 male test subjects (aged 45-55) before and after 30-day enclosure. The greatest changes were seen in the composition of free fatty acids of lipids of the facial skin (increase of palmito-oleic acid). The lipid composition of the sebum cutaneum of the healthy subjects differed from that of the acne-bearing subjects. It is recommended to use the ratio of palmitic acid to palmito-oleic acid as a measure of changes of fatty acids in the sebum cutaneum of healthy people in an unusual environment.

[Effect of long-term hypokinesia on the serum lipid spectrum]. / Vliianie dlitel'noi gipokinezii na lipidnyi spektr syvorotki krovi.

The effect of 120-day head-down tilt on the lipid spectrum of blood serum was investigated. By thin-layer and gas liquid chromatography lipids (total lipids, phospholipids, cholesterol and its esters, nonesterified fatty acids, triglycerides) and higher fatty acids were identified. It was found that cholesterolemia increased at the expense of the ester bound fraction, phospholipids decreased drastically, the ratio of phospholipids to total cholesterol decreased, and triglyceridemia diminished. Until bed rest day 70 saturated fatty acids were predominant, with linoleic acid being deficient, and thereafter the relative content of unsaturated fatty acids increased. The above changes in the lipid spectrum can be considered as risk factors with respect to preclinical stages of atherosclerosis.