Peculiar characteristics of crewmembers' metabolism on the second expedition aboard orbital station Salyut-4.

This paper presents the results of metabolic studies of crew members on the second expedition aboard orbital station Salyut-4. Pre- and postflight medical examinations included measurements of a wide range of biochemical parameters characterising protein and carbohydrate metabolism, enzyme activity, energy exchange in red blood cells, hormone concentration, etc. It was shown that, during the 63-d flight and 7-d recovery period, crew-members developed no metabolic changes which could suggest pathologies. The changes were functional and seemed to be manifestations of adaptive reactions to space flight and return to 1 G. Elucidation of mechanisms of the reactions requires further study.

Free amino acids in human blood plasma during space flights.

The present investigation presents results of studying free amino acids of peripheral plasma in cosmonauts who made space flights of different duration onboard the spacecraft Soyuz-12, Soyuz-16 and the orbital station Salyut-4. The study showed changes in the content of free amino acids which varied for different amino acids. Most pronounced changes were found in the content of glutamic and aspartic acids, sulfur-containing amino acids and arginine.

Metabolic and hormonal status of crewmembers in short-term spaceflights.

In order to clarify biochemical adaptation of the human body to short-term microgravity, metabolic and hormonal parameters were investigated in 20 cosmonauts who performed orbital flights of 4 to 14 d in duration. The specific feature of adaptation to this exposure is the transition to a new level of hormonal regulation with a significant increase of the content (production) of glucocorticoids, catecholamines, components of the renin-angiotensin-aldosterone system, which determines a modified activity of tissue hormones, and fluid-electrolyte homeostasis, as well as simultaneous increase of insulin secretion that diminishes the metabolic effects of glucocorticoids and catecholamines.

Some aspects of energy metabolism in human blood erythrocytes under hypokinesia and during space flights.

The present investigation presents results of studying energy metabolism in blood erythrocytes in cosmonauts who made the first and the second space flights aboard the orbital station Salyut-4 and in test subjects who experienced 49-d of hypokinesia at -4 degrees. The data obtained throughout the postflight investigations and during the hypokinesia studies appeared to be identical, showing a decrease in glycolytic activity whereas ATP content remained unchanged.

Effect of 1 alpha-hydroxy-cholecalciferol and varying phosphorous content in the diet on calcium phosphorous metabolism in hypokinetic rats.

Hypokinesia induces mineral changes, including changes in calcium and phosphorus metabolism, which involve their increased renal excretion, deposition in soft tissues, and development of osteoporosis. These experiments were designed in order to ascertain the role of active metabolites (hydroxy-cholecalciferol) and changes in phosphorus in the diet on calcium accumulation in bone, soft tissue, and renal calcinosis, and changes in calcium-phosphorus metabolism in rats during prolonged and severe hypokinesia.

Effect of vitamin and amino acid supplements on human performance during heavy mental and physical work.

This paper presents data describing the effects of vitamin and amino acid supplements on the health state and performance of men doing heavy mental and physical work. Experiments on seven test volunteers showed that a 20-d intake of a mixture of vitamins, amino acids, and mineral substances optimized the health state and increased the performance of test subjects doing heavy work.

Vitamin D3 active metabolites as a countermeasure against disorders of calcium-phosphorus metabolism in hypokinetic rats.

Male Wistar rats that were experimentally hypokinetic were fed 24,25(OH)2D3 or 1,25(OH)2D3 separately or in combination to determine the effect on bone growth and on bone formation and resorption. It was shown that these parameters of bone metabolism are influenced by these metabolites of vitamin D3 by their effect on bone sensitivity to their activity and perhaps in the regulation of bone histogenesis.

Bone tissue of hypokinetic rats: effects of 24,25-dihydroxycholecalciferol and varying phosphorous content in the diet.

Severe hypokinesia of rats given the diet with a ratio of Ca:P = 1:0.5-1:3 was accompanied by hypocalcemia, development of osteoporosis, and some intensification of renal calcinosis. The decrease of phosphorus consumption (Ca:P = 1:0.5-1:1) prevented a development of these changes in intact animals and increased bone mineralization in hypokinetic ones. Excessive phosphorus consumption (Ca:P = 1:3) produced hypocalcemia, hyperphosphatemia, and some osteoporotic changes in the bones of intact animals and intensified these changes with hypokinesia. Administration of 24,25-dihydroxycholecalciferol, an active metabolite of vitamin D3, at a dose of 1.25 micrograms/d prevented a development of bone disorders, thus effectively stimulating diaphyses and epiphyses mineralization and correcting hypocalcemia in hypokinetic rats. 24,25(OH)2D3 at the same dose did not intensify nephocalcinosis and produced no toxic symptoms with hypokinetic animals.

[Effect of 24,25-dihydroxycholecalciferol on chemical composition of the rat bone tissue during hypokinesia]. / Vliianie 24,25-dioksikholekal'tsiferola na khimicheskii sostav kostnoi tkani krys pri gipokinezii.

Severe hypokinesia in rats, maintained on rations with the Ca:P ratios from 1:0,5 to 1:3, was accompanied by hypocalcemia, osteoporosis and a slight increase in kidney carcinosis. Decrease in phosphorus consumption (Ca:P = 1:0,5 - 1:1) enabled to prevent these impairments in the intact animals and led to an increase in the rate of bone tissue mineralization in hypokinesia. An excessive utilization of phosphorus (Ca:P = 1:3) caused hypocalcemia, hyperphosphatemia and a slight osteoporotic destructions in bone tissue of intact animals increasing the severity of these impairments in hypokinesia. 24,25-Dihydroxycalciferol (24,25 (OH)2D3) at a daily dose 1.25 micrograms per an animal inhibited the osteoporotic destructions, stimulating mineralization of the diaphyses and epiphyses and corrected the hypocalcemia in rats under conditions of hypokinesia. 24,25 (OH)2D3 at the dose used did not increase nephrocalcinosis as well as did not exhibit a toxic effect, estimated in hypokinetic rats by alteration in body mass.

[Calculation of energy losses in the participants of the skiing expedition to the North Pole]. / Raschety énergotrat uchastnikov lyzhnoi ekspeditsii k Severnomu poliusu.

During the expedition to the North Pole, the food consumption rates were calculated on a regular basis. The mean daily energy losses of the participants of the expedition, the energy losses during skiing with a rucksack across the drifting ice were estimated and the energy metabolism curve by days was built up. The body weight of the participants averaged 78 +/- 5 kg. This made it possible to perform an overall calculation per whole group. The total energy supply with food was appraised from the total amount of the food consumed during the expedition. The total body weight loss of the participants was 11.5 kg, the energy consumption being 100.000 kkal. The total (for 7 men) energy consumption during skiing without a rucksack was calculated according to the formula: [(2,770 kkal X 28.5 days)]+ +[(2,385 kkal X 35.5 days)]. It was thus found to be equal to 1.145.300 kkal. The total energy consumption during skiing with a rucksack was calculated according to the formula: (7 men X X 449 h) and was found to be equal to 1.883.200 kkal. The total energy consumption during the expedition amounted to 3.237.500 kkal. During the expedition, the daily energy deficiency per man was 1.300-1.500 kkal. This deficiency was compensated for during rest. The maintenance of such an energy supply pattern made it possible to preserve a high level of work fitness.

[Amino acid assimilability in human dietary protein deficiency]. / Usvoiaemost' minokislot pri alimentarnoi belkovoi nedostatochnosi u cheloveka.

The effect of different levels of protein in he diets (15.1 +/- 0.3; 9.4 +/- 0.2; 8 +/- 0.4; 4.6 +/- 0.3 g nitrogen a day) on assimilation of amino acids in man was studied. The rates of endogenous excretion of 18 amino acids with feces were determined in the course of protein-free nutrition. It has been shown that as the body supply with protein decrease the assimilation of most amino acids rises. It has been proved experimentally that it is not wise using the index of "seeming" assimilation in determination of amino acid assimilation.

[Free amino acid ratio in the blood plasma in human protein deficiency]. / O sootnoshenii nekotorykh svobodnykh aminokislot v plazme krovi pri belkovoi nedostatochnosti u cheloveka.

The content of free amino acids (valine and arginine) and their ratio (V/A ratio) in the blood plasma was studied in men (4 groups each holding 5 persons) kept on controlled diets with varying content of protein nitrogen. The experiments made it possible to reveal definite changes in the V/A ratio depending on the amount of protein nitrogen in the diet. The ratio was demonstrated to descend as a result of inadequate supply of protein nitrogen with the diet. To form the final judgement about the diagnostic significance and specificity of the indicator under consideration, it is necessary to perform careful check-ups under clinical and experimental conditions.

[Calcium absorption in the small intestine in rats during hypokinesia]. / Vsasyvanie kal'tsiia v tonkoi kishke krys pri gipokinezii.

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 26.3%) calcium transport was established in adult rats after 4 weeks of hypokinesia. In young rats a significant lowering of the active calcium transport was already noted after 1 week of hypokinesia, however, age-dependent shifts in the process were more significant than those induced by hypokinesia. Changes in the calcium-regulating hormones are considered as a possible cause of decreased calcium absorption in the intestine in relation to hypokinesia and age.

[Human nutrition in prolonged autonomous crossings over drifting ice]. / Pitanie liudei v dlitel'nykh avtonomnykh perekohdakh po dreifuiushchim l'dam.

The authors describe the experience gained with nutrition for participants of ski transitions over drifting ice of the Arctic, organized by the newspaper "Komsomolskaya Pravda" in 1972, 1976 and 1979, including a 76-day transition towards the North Pole. Use was made of dehydrated products with a daily diet mass of 800-3300 g per man, in which fat content was 40-45% of total caloricity, and that of proteins 12-18%. Hot food was taken not less than 2 times a day (breakfast and supper). If the number of transitions exceeds 8-9 a day, it is necessary to have daytime rest and to take hot food. Additional intake of vitamins, particularly of vitamin C, is required, especially during transitions lasting over 20-25 days. If the transitions last over 35-40 days, it is required that additional food and fuel should be supplied. Optimal duration of the intervals between additional food supplies constitutes 12-15 days, the maximal permissible one 25-30 days. It is advisable to have rest days and high-caloric diet every other 15-20 days. The daily energy deficiency amounting to 1250-1500 kcal per man enables the trained group to maintain high physical and intellectual working capacity. However, overall energy deficiency should not exceed 30 000-40 000 kcal per man.

[Nutritional pattern of the "Komsomolskaya Pravda" Arctic expedition]. / K voprosu o pitanii poliarnoi ekspeditsii "Komsomol'skoi Pravdy"

Data on the chemical composition, nutritional value and caloricity of food ration used by the "Komsomolskaya Pravda" expedition during ski marches in the Arctics are reported. The rations consisted chiefly of dehydrated products and weighed 800-1000 g. The daily caloricity of the rations amounted to 3400 and 4400 great calories.