[Cytophotometric analysis of the cell population composition of the the preoptic area of the hypothalamus in the common frog]. / Tsitofotometricheskii analiz sostava kletochnoi populiatsii preopticheskoi oblasti gipotalamusa travnoi liagushki.

DNA contents in squashed cells of the adult frog hypothalamic preoptic region (HPR) were measured using the Feulgen and UV cytophotometry techniques. The histone-DNA ratio in the cell nucleus was determined by means of a combined Feulgen-heparin-Alcian blue staining procedure. The nuclei of the vast majority of HPR cells have a diploid DNA content. However, in cells of this group the mean values of DNA amount and the distribution range were always higher than those in hepatocytes used as a diploid standard. Such a heterogeneity in DNA content in the diploid part of HPR cell population could apparently suggest some differences in the nuclear chromatin arrangement to be always higher in spring before the frog spawning, and it seems to be characteristic of this type of cells. About 1 per cent of cells with hyperdiploid surplus of DNA (H2c cells) as well as of tetraploid cells (4c and 2c X 2 cells) is found in HPR in frogs sacrificed both in winter and in summer. The quota of these cells has no reference either to the frog's age or to the annual cycle. The fact that the mean DNA values in H2c and 4c cells are much higher than in the standard cannot be explained by the presence of different amounts of nuclear proteins only. It is suggested that at least some part of the highest DNA values may be due to an actual extra DNA synthesis in a small constantly existing pool of HPR cell population.

[Human blood glutamic acid in exposure to elevated ammonia levels in the gaseous environment]. / Glutaminovaia kislota krovi cheloveka pri vozdeistvii povyshennogo soderzhaniia ammiaka gazovoi sredy.

Amino acid metabolism of men kept in a enclosed environment was investigated. A high concentration of ammonia produced a specific redistribution of free amino acids in plasma with the content of glutamic acid increasing by the end of study. The estimates of glutamic acid in blood can be used for assessing maximally allowable concentrations of ammonia in enclosed environments.

[Biological value of proteins in food rations of crews on Saliut orbital stations]. / Biologicheskaia tsennost' belkov ratsionov pitaniia ékipazhei orbital'nykh stantsii "Saliut".

The biological value of the protein component of three modifications of the Salyut space diet was measured in laboratory studies and in simulated space flights. Three experimental runs of up to 68 days in duration were carried out on 20 volunteers. During the study the following parameters of protein metabolism were measured: total protein and protein fractions in serum; urea, uric acid and creatinine in blood; total nitrogen, urea, ammonia, uric acid and creatinine in urine. The results obtained showed that the diet modifications provided an adequate nutritional status and a normal level of the above parameters of protein metabolism.

[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]. / Vliianie diet s aktivnym metabolitom vitamina D 3 i razlichnym soderzhaniem kal'tsiia i fosfora na sostav svobodynykh aminokislot krovi krys pri gipokinezii.

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. The use of 24, 25 (OH)2D3 promoted the recovery of the amino acid status of hypokinetic rat blood, while the optimization of the Ca and P content in the diet was absolutely indispensable.

[Effect of limited motor activity on the alanine level of human blood plasma]. / Vliianie ogranicheniia dvigatel'noi aktivnosti na uroven' alanina v plazme krovi cheloveka.

The plasma alanine concentration was measured in 28 healthy male test subjects exposed to head-down tilt of various duration (2-hour exposure at-12 degrees, 7-day exposure at-6 degrees, 49-day exposure at-4 degrees, and 120-day exposure at-4 degrees). Head-down tilt led to alanine changes that correlated with exposure time. These results suggest that alanine concentrations in blood reflect to a certain extent the rate of hepatic gluconeogenesis and depend significantly on the hypokinetic time. The findings can be clinically used as a measure of hepatic gluconeogenesis in bed-ridden patients that may require preventive or therapeutic treatment.

[Various aspects of amino acid metabolism in humans exposed to 120-day anti-orthostatic hypokinesia]. / Issledovanie nekotorykh storon aminokislotnogo metabolizma u cheloveka v usloviiakh 120-sutochnoi antiortostaticheskoi gipokinezii.

The free amino acid pool of blood of man exposed to 120-day head-down tilt (at -4 degrees) was examined. Beginning with bed rest day 28 and till the end of the study, the amino acid pool increased. The increase involved most free amino acids which was produced by a decline of anabolic and stimulation of catabolic processes during hypokinesia.

[Human amino acid metabolism during combined short-term exposure to head-down tilt hypokinesia and ultraviolet irradiation]. / Issledovanie nekotorykh storon aminokislotnogo metabolizma u cheloveka v usloviiakh kratkovremennogo sochetannogo vozdeistviia antiortostaticheskoi gipokinezii i ul'trafioletovogo oblucheniia.

Changes in the amino acid pool in the plasma of test subjects exposed to short-term head-down tilt combined with ultraviolet irradiation were investigated. Exposure to head-down tilt alone (Group 1 of 3 test subjects) and combined with ultraviolet irradiation (10 sessions) (Groups 2 and 3 of 3 test subjects each) acted as a stress-agent that diminished the amino acid pool. Exposure to 2-hour head-down tilt in combination with 20 UV-irradiations (Groups 2 and 3) increased the amino acid pool as a result of inhibition of anabolic and stimulation of catabolic processes. The amino acid pool did not return to normal within the recovery period allowed.

[Possibilities of using proteins from unicellular algae in biological life support systems]. / Perspektivy ispol'zovaniia belka odnokletochnykh vodoroslei v biologicheskikh sistemakh zhizneobespecheniia cheloveka.

The concentration, amino acid composition and biological value of proteins of unicellular algae belonging to various taxonomic groups (Chlorella, Chlamydomonas, Spirulina, Euglena) were investigated. With respect to their characteristics, these algae hold promise as components of biological life-support systems (BLSS). Indices characterizing the protein and biomass quality and biological value were calculated. Such indices as A/E (where A is an essential amino acid and E is the sum total of amino acids), E/T (where E is nitrogen of essential amino acids and T is its sum total), amino acid number, factor of digestibility in vitro were high enough and close to the respective parameters of the reference protein. Animal experiments showed high biological value of the algal biomass and the lack of its toxic or other adverse effects. The data on the quantity and quality of protein from the unicellular algae are indicative of its high biological value and applicability to BLSS. It is suggested that the differences in the protein composition associated with various algal forms and cultivation conditions can be used to produce balanced diets by varying the portion of each form of the photoautotrophic component of BLSS.

[Amino acid composition of human blood serum during immersion hypokinesia]. / Aminokislotnyi sostav syvorotki krovi cheloveka v usloviiakh immersionnoi gipokinezii.

The content of free amino acids was measured in the blood serum of 6 male test subjects exposed to 7-day immersion. During the study the concentration of amino acids decreased in a different manner typical of a stress-effect. The results obtained can be used to develop a system of prevention and therapy of amino acid unbalance.

[Free amino acids of blood plasma in astronauts during pre-flight training]. / Svobodnye aminokisloty plazmy krovi u kosmonavtov v period podgotovki k poletu.

Taking into consideration metabolic specificities of cosmonauts, the data on their amino acid composition during preflight training were summarized. Seasonal variations produced no effect on the content of free amino acids of plasma. The analysis yielded a physiological norm for this population which can be used to identify more reliably changes in the amino acid composition of plasma after space flight.

[Free amino acids in the blood before and after short-term space flight]. / Svobodnye aminokisloty krovi do i posle kratkovremennykh kosmicheskikh poletov.

The amino acid composition of plasma and serum of the crewmembers who performed short-term space flights (of 3 to 14 days) onboard the Salyut-6 orbital station was investigated. Immediately postflight total amino acids remained unchanged while variations in isolated amino acids (tendency toward increased aspartic acid and decreased cysteine in plasma, and increased leucin in serum) were adaptive.

[Effect of hypokinesia on amino acid metabolism in rats on diets containing different amounts of calcium and phosphorus]. / Vliianie gipokinezii na fone ratsionov pitaniia s razlichnym sootnosheniem kal'tsiia i fosfora na aminokislotnyi metabolizm u krys.

The effect of hypokinesia on amino acid metabolism was studied in rats kept on diets with different ratios of calcium and phosphorus. It was shown that excessive phosphorus in the diet led to a significant decrease of the amino acid pool, thus aggravating the hypokinetic effect.

[Effect of long space flights on amino acid metabolism]. / Vliianie dlitel'nykh kosmicheskikh poletov na aminokislotnyi metabolizm u cheloveka.

The amino acid composition of the plasma and serum of Salyut-6 crewmembers who performed flights of different duration was investigated. The parameter was found to vary depending on the flight time and use of different countermeasures. The 75- and 185-day cosmonauts who did not exercise in a full measure showed a decrease in the amino acid pool typical of emergency situations. The 96-, 140- and 175-day crewmembers who exercised as prescribed exhibited the lack of changes in the total content of amino acids and variations in the content of individual amino acids. The results of the study of the amino acid composition can be applied to the evaluation of inflight countermeasures, e.g. exercises, and to the development of rehabilitation measures postflight.

[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.

[Amino acid composition of the rat quadriceps femoris muscle after a flight on the Kosmos-936 biosatellite]. / Issledovanie aminokislotnogo sostava chetyrekhglavoi myshtsy bedra krys posle poleta na biosputnike "Kosmos-936".

The amino acid composition of the quadriceps muscle of rats flown onboard the biosatellite Cosmos-936 and exposed to the ground-based synchronous control experiment was studied. The weightless rats showed changes in the amino acid concentration in the quadriceps muscle. The centrifuged flight and synchronous rats displayed an accumulation of free amino acids in the above muscle.

[Amino acid metabolism in long-term nutrition with dehydrated products and in the modelling of space-flight factors]. / Ob obmene aminokislot pri dlitel'nom pitanii obezvozhennymi produktami i modelirovanii nekotorykh faktorov kosmicheskogo poleta.

Forty-two healthy volunteers, aged 19 to 49, participated in three bed rest studies of 69 to 180 days in duration. The test subjects were kept on the diet consisting of dehydrated foods: fresh, stored for up to 2 years, and exposed to proton irradiation at a dose of 24,000 rad. Metabolism of amino acids was investigated under these conditions. It was concluded that during prolonged storage and irradiation proteins of dehydrated foods retained their biological value. This allows their use in long-term space flights.

[Amino acid composition of the body of rats after a flight on the Kosmos-1129 biosatellite]. / Issledov anie aminokislotnogo sostava tela krys posle poleta na biosputnike "Kosmos-1129".

The paper presents data concerning the amino acid pool of rats flown on board Cosmos-1129 and exposed to the ground-based synchronous experiment. Certain changes in the amino acid pool of flight and synchronous rats have been found. The changes seem to be associated with the selective rate of incorporation of free amino acids into the biosynthetic processes during acute adaptation and with alterations in the protein synthesis rate.