[Role of ultraviolet radiation and vitamin D metabolism in medical care during space flights]. / Rol ultrafioletovoi radiatsii i obmena vitamina D pri meditsinskom obespechenii kosmicheskikh poletov.

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 effect of super-erythematous doses of UV-radiation on the general condition of the human body]. / Vliianie superéritemnykh doz UF-radiatsii na obshchee sostoianie organizma cheloveka.

The effect of excessive UV-radiation with 2-4, 5-6, or 7-8 minimal erythematous doses (MED) on man's health condition was investigated, when the irradiated surface area made 20% or 50% of the body surface area. Before and 1 or 3 days after exposure the following parameters were measured: skin state, skin perspiration, body temperature, fluid consumption, diuresis, ECG, PCG, occlusion plethysmography. The observations allowed the conclusion that 5-8 MEDs were threshold doses inducing early intoxication in response to local irradiation (20% of the body surface area) and upper body irradiation (50% of the body surface area). Irradiation with 7-8 MEDs caused noticeable intoxication: fever, headache, increased body temperature (37 degrees C and over), inhibited perspiration, fluid retention, and altered cardiac function.

[The duration of the aftereffects of UV-irradiation of man in conditions of UV-insufficiency]. / O dlitel'nosti posledeistviia UF-oblucheniia cheloveka v usloviiakh UF-nedostatochnosti.

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 0.035, 1.75, or 0.65 W/m2, respectively. Group 1 subjects (5 men) were exposed to UV-B-irradiation 10 times (once with 0.5, 0.6, 0.75, 0.9, 1.1, 1.35, 1.65 MED and three times with 2.0 MED) and Group 2 subjects (4 men) were exposed to UV-B-irradiation 20 times (twice with 0.5, 0.75, 1.0, 1.25, 1.5, 1.75 MED and eight times with 2 MED). The sessions were arranged every other day. The exposure produced a beneficial effect on the human body: skin sensitivity decreased, resistance of skin capillaries increased, Ca metabolism normalized, blood 25 (OH) D grew. The trend of responses was similar after 10 and 20 sessions; however, 20 sessions caused a longer-term aftereffect. In relation to space programs, it is concluded that UV-irradiation can be applied on the ground before short-term flights (less than 4 months) and in space during longer-term flights (greater than 4 months).

[Effects of increased doses of ultraviolet radiation on several parameters of human metabolism]. / Vliianie povyshennykh doz ul'trafioletovoi radiatsii na nekotorye pokazateli obmena veshchestv cheloveka.

Three experimental series, in which 20 test subjects took part, were carried out to investigate the effect of super-erythemic doses of ultraviolet irradiation on metabolic parameters. It was found that UV irradiation of 12-15% of the skin area led not only to skin changes but also to functional changes in certain organs and systems, which was indicated by variations of metabolic parameters.

[Measurement of the temperature of deep-seated tissues in healthy men during hypokinesia]. / Issledovanie glubinnykh temperatur tkanei zdorovogo cheloveka v usloviiakh gipokinezii.

During a head-down tilt (-5 degrees) study, in which 10 healthy male subjects took part, their body temperature variations were investigated. Skin temperature was measured using and electrothermometer with a point sensor-thermistor and core temperature was measured using a radiothermometer at the wavelength 20 cm. The study showed that the distribution profile of core temperature was close to that of skin temperature: the lowest temperatures were characteristic of the limbs and the highest of the chest, stomach and head. During head-down tilt variations in core temperatures were different from those of skin temperature. As a result, the temperature gradient between the skin and core layers increased by bed-rest day 50. In the subjects who regularly exercised during bed rest the gradient grew because their skin temperature fell while in the subjects who did not exercise the gradient increased due to both factors, i.e. skin temperature decrease and core temperature increase.

[Prevention of ultraviolet insufficiency after a long stay by humans in an isolation chamber]. / Profilaktika ul'trafioletovoi nedostatochnosti pri dlitel'nom prebyvanii cheloveka v izolirovannom pomeshchenii.

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 0.75 MED and 20 exposures at incremental doses from 0.5 to 2 or 3 MED. Before and after 10 and 20 exposures (with medium-range radiation being predominant) the skin state, vitamin and mineral metabolism, and cytotoxicity of natural killers were investigated. The experimental observations allowed the conclusion that prophylaxis of UV insufficiency in men long kept in an enclosure can best be provided by UV irradiation at an incremental dose up to 2 MED. During this exposure skin sensitivity to UV radiation decreased, the content of vitamins D, A, E and that of Ca, P, Cu grew, and cytotoxicity of natural killers lightly increased. UV irradiation at a dose of 0.75 MED proved inadequate and that at a dose of 3 MED induced signs of excessive irradiation.

[Dynamics of changes in the fluids of the extremities in man in different body positions]. / Dinamika obmena zhidkikh sred v konechnostiakh cheloveka pri razlichnom polozhenii tela.

Anthropometric measurements and occlusion venous plethysmography were used to investigate fluid inflow and outflow in the limbs of human subjects who kept normal motor activity for 4 hrs, remained in recumbency or were in the head-down position at an angle of -12 degrees and -22 degrees (to simulate effects of zero G). During these exposures diuresis, heart rate and blood pressure according to Korotkoff were also measured. In the horizontal and, to a greater extent, head-down position, when motor activity was diminished, volume blood flow velocity in the limbs decreased, i. e. blood inflow to them became smaller. Arm volume varied insignificantly since inflow and outflow were in balance whereas leg volume decreased because fluid outflow was larger than inflow. In the head-down position the tone of leg veins also declined. Thus the peripheral vascular bed developed a complex of mechanisms that were to prevent volume overload of the central bed. Fluid shifts from the legs to the central bed were made up for by the renal excretion of water in the horizontal and head-down (-12 degrees C) (-22 degrees) produced a stressful effect on compensatory mechanisms which manifested as a greater rise of diastolic pressure and bradycardia. The data obtained indicate an active involvement of the peripheral vascular bed in the adaptation to diminished motor activity in the horizontal and head-down position of human subjects.

[Prospects for using ultraviolet radiation in protracted space flights]. / Perspektivy primeneniia ul'trafioletovoi radiatsii v dlitel'nykh kosmicheskikh poletakh.

The data concerning UV-effects on the human body and the environment are reviewed as applied to long-term flights. It is concluded that UV-radiation can be used in long-term space flights in view of its vitamin-forming, desensitizing, bactericidal, and supporting properties to improve the environment and to prevent adverse effects of space flight factors.

[Effect of different doses of ultraviolet radiation on vitamin provision to the human body]. / Vliianie razlichnykh doz ul'trafioletovogo oblucheniia na obespechennost' organizma cheloveka vitaminami.

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. However, the vitamin concentration in blood was not significantly decreased. This can be explained by the adaptation of the human body to UV-irradiation upon a continuous increase of its dosage.

[Vascular mechanisms of adaptation to head-down tilt body posture]. / Sosudistye mekhanizmy adaptatsii k antiortostaticheskogo polozheniiu tela.

Using occlusion plethysmography and rheography, the state of peripheral circulation of 18 test subjects during 25 exposures to head-down tilt was investigated. The test subjects were subdivided into two groups: nine subjects actively changed their body position by 90 degrees and nine others were passively transferred to the head-down position at an angle of -12 degrees. It was found that regular training facilitated the development of vascular mechanisms which assisted adaptation to the head-down tilt: it decreased the tone of resistance vessels of the arms and legs and that of capacitance vessels of the legs; it increased the tone of cerebral resistance and capacitance vessels. The tone of leg capacitance vessels varied, depending on the type of training: passive tilting increased their compliance and active tilting decreased it. The final result of the tone redistribution in the peripheral vascular bed during training was a smaller increase of head blood content and a smaller fluid outflow from the legs.

[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.

[Human motor activity during its artificial restriction]. / Dvigatel'naia aktivnost' cheloveka pri ee iskusstvennom ogranichenii.

During a prolonged exposure to an altitude chamber (37-120 days) man's motor activity decreases 3- or 4-fold: from 15-19 thous. to 2-4 thous. steps per day. During a prolonged restraint in a chair in the position of "an average physiological rest" the number of movements falls to 5-7 per hour. The change of motor activity during hypodynamics and recovery follows three stages: an acute change, a slow change, and a stage of stabilization at a new level. It has been shown that the people who find themselves in an environment limiting their physical activity do not have the need for an additional workload.