[Role of ultraviolet radiation and vitamin D metabolism in medical care during space flights].

Data on the development of ultraviolet (UV) deficiency in the cosmonauts are analyzed, possible ways to optimize UV radiation and alimentary stearin supply in order to prevent vitamin D deficiency and to correct the changes in phosphorous-calcium metabolism are discussed.

[The duration of the aftereffects of UV-irradiation of man in conditions of UV-insufficiency].

The purpose of the present investigation was to study the aftereffect of UV-B-irradiation applied during 10 or 20 sessions. The biological effect and aftereffect duration of UV-B-irradiation of the upper body of 9 healthy volunteers (residents of the city of Moscow and its suburbs) were evaluated in autumn and winter. During UV-irradiation in the range 220-280, 280-320, or 320-400 nm the flux density was 0.

[Effect of simulated weightlessness on calcium metabolism and the condition of bone tissue in experimental animals].

Male rats of the Wistar strain were for 40 days exposed to hypokinesia and hypodynamia. After exposure bone biochemical, physical, chemical, morphological and strength parameters were investigated. Both simulation studies led to changes in calcium and phosphorus metabolism but the nature of bone changes was different.

[Effect of active metabolites of vitamin D 3 on the status of rat bone tissue in various experimental models of hypokinesia].

Rats were for 6 weeks either kept in small cages or suspended. The caged rats showed hypocalcemia and lowered active transport of calcium in the intestine and no changes of PTH in blood. Femoral bone measurements in these rats revealed reduced density and content of calcium and phosphorus in proximal epiphyses, slight increase of these parameters in diaphyses and lack of changes in distal epiphyses.

[Prevention of ultraviolet insufficiency after a long stay by humans in an isolation chamber].

The purpose of this study was to investigate biological effects of various regimens of ultraviolet irradiation in order to prevent UV insufficiency in men long kept in an enclosure. The subjects were kept for 60 days under artificial illumination in a Moscow laboratory in winter time. Two different regimens of UV irradiation were used and compared: 20 exposures at a dose of 0.

[Study of the activity of various systems of neurohumoral body regulation and ways of its correction in an arid area].

The sympatho-adrenal system, i.e. its hormonal and mediator components, were examined in test subjects who made a 23-day expedition across a desert.

[Comparative study of the effect of 1,25 dihydroxyvitamin D3 and 24,25-dihydroxyvitamin D3 on calcium homeostasis and bone tissue state in rats during hypokinesia].

Preventive administration of vitamin D3 active metabolites 1.25(OH)2D3 and 24.25(OH)2D3 into growing rats, kept under conditions of long-term hard hypokinesia, normalized Ca metabolism and the state of bone tissue depending on the preparations dose and their combination.

[Calcium absorption in the small intestine in rats during hypokinesia].

The method of averted and non-averted segments was used to assess calcium absorption in the small intestine of adult and young rats with hypokinesia. A certain decrease in the active (by 13.8%) and more manifest diminution of the total (by 26.

[Vitamin allowance of cosmonauts during preflight training and after completing short space flights].

Supply of the main and doubling crews of cosmonauts with vitamins C, A, D, E, B1, B2, B6, PP, and B12, folic acid and carotinoids was studied during training and after the completion of short-term space flights (from 4 to 13 days). As the result of the investigation conducted during the intensive training, 1 month before the space flight some cases of certain vitamins deficiency were revealed. Administration of additional vitamins during 2 weeks before the flight led to a rise in the cosmonauts' supply with vitamins.

[Effects of diets including an active vitamin D 3 metabolite and different contents of calcium and phosphorus on the state of blood free amino acids in hypokinetic rats].

Some aspects of amino acid metabolism in rats exposed to 30 days of hypokinesia were explored. The animals were placed on the diets with varying Ca/P ratio, containing 24, 25-dihydroxycholecalciferol (24, 25 (OH)2)D3, an active vitamin D3 metabolite. It was demonstrated that high consumption of phosphorus brought about an appreciable reduction in the blood amino acid pool, thus aggravating the body response characteristic for hypokinesia.

[Effect of different doses of ultraviolet radiation on vitamin provision to the human body].

Exposure of healthy adults to prophylactic doses of UV-radiation in the medium- and long wavelength spectrum improved metabolism of vitamins A, E and D and increased their content in the body. UV-irradiation even in prophylactic doses increased ascorbic acid requirements. Excessive UV-irradiation produced an adverse effect on the vitamin content.

[Role of active vitamin D3 metabolites in regulating calcium metabolism in rats during hypokinesia].

The rats exposed to prolonged hypokinesia showed hypocalciemia, lower PTH and higher calcitonin concentrations in the serum, decreased calcium absorption in the small intestine, and a trend toward nephro- and arteriocalcinosis. Prophylactic administration of 24,25-hydroxy D3. 1,25-hydroxy D3 and their combinations enhanced calcium absorption and alleviated hypocalciemia.

[Catecholamine metabolism in a high-altitude environment].

The function of the sympathoadrenal system (SAS) measured with respect to the content of epinephrine and norepinephrine in blood and urine as well as dopamine and DOPA in urine of mountaineers and athletes nontrained to high altitudes was examined. It was found that the mediator component of the SAS was activated in the athletes and that the adaptive capability of the SAS of the mountaineers was adequately high. It is recommended to study the SAS activity as a diagnostic test for measuring the fitness of members of expeditions in an unusual environment.

[Comparative study of the toxicity of 1 alpha-hydroxyvitamin D3 and 24,25 (RS)-dihydroxyvitamin D3 in rats].

The toxic effects of 1 alpha (OH)D3 and 24,25 (OH)2D3 administered in doses of 0.25, 2.5 and 25 micrograms per animal a day were compared in rats weighing initially 230-260 g and fed an artificial diet containing 0.

[Diet for the first expedition of Soviet climbers to Mount Everest].

Biomedical requirements for the diets to be used by the Soviet mountaineers during their Everest expedition have been determined, employing the experience of Soviet mountaineers who have ascended the highest summits in this country, dietary data accumulated by the mountaineers who have conquered the Himalaya Mountains and the Karakoram Range, as well as current concepts of human physiology and biochemistry in highlands. This paper presents the major nutritional parameters of the diets and the arrangement of meals. The Soviet mountaineers were on the whole happy with the diets and showed no disorders in the health state, gastrointestinal system or digestive function that can be of nutritional origin.