[Effectiveness of anti-G devices of the nonchamber type after head-down tilt hypokinesia lasting up to 7 days]. / Issledovanie éffektivnosti protivoperegruzochnykh ustroistv beskamernogo tipa posle ANOG prodolzhitel'nost'iu do 7 sut.

In three experimental series in which 34 male test subjects (aged 20 to 31 years) participated, acceleration tolerance (+Gz) was measured before and after exposure to 7-day head-down tilting. The measurement tests were performed using an antigravitational device in two modifications AGU-1 and AGU-2. After tilting, tolerance to sustained acceleration +Gz decreased significantly. The use of the device helped to increase acceleration tolerance, AGU-1 all the test subjects tolerated acceleration up to 4.0 G while in AGU-2 only up to 3.0 G. The use of the AGU device following exposure to antiorthostatic hypokinesia helped to maintain the high quality of operator's activities as compared to the controls.

[Various reactions of the human body during 7 days of anti-orthostatic hypokinesia]. / Nekotorye reaktsii organizma cheloveka v usloviiakh semisutochnoi antiortostaticheskoi gipokinezii.

Time-course variations in the cardiovascular parameters, vestibulo-autonomic stability, work capacity and nutritional status were measured in 20 male test subjects, aged 19-22, who were exposed for 7 days to head-down tilt (-10 degrees). Beginning with days 3 or 4, new hemodynamic ratios developed that indicated a new level of circulation regulation and adaptation to head-down tilt. It appears that blood redistribution towards the head led to an enhanced vestibulo-autonomic stability. Renal excretion of nitrogen increased, reaching the highest level on days 6-7. The investigations allow the conclusion that 7-day head-down tilt may cause changes in almost every physiological system.

[Effect of hypokinesia and +Gz loads on the transport function of blood in man]. / Vliianie gipokinesii i peregruzok +Gz na transportnuiu funktsiiu krovi cheloveka.

The results of 44 studies of circulation parameters and blood transport function of 14 test subjects exposed to 7-day bed rest (-10 degrees head-down tilt) and acceleration -4.5 Gz have demonstrated that the blood transport carriers and their actively binding centers form working structures in the adaptive reactions. As compared to the pretest level, the distribution ratio of 14C-adenine between two immiscible phases (plasma/oil, erythrocytes/oil) varies from -12 to 14% on bed rest day 3 to +32 to 40% on bed rest day 7; it increases by 145-150% after exposure to acceleration +4.5 Gz. The parameters of the blood transport function give a quantitative description of its adaptive reactions to environmental effects.

[Possibilities of preventing the adverse reactions in modeling the acute period of adaptation to weightlessness]. / Nekotorye vozmozhnosti profilaktiki neblagopriiatnykh reaktsii pri modelirovanii ostrogo perioda adaptatsii k nevesomosti.

It has been shown that during head-down tilting at an angle of -30 degrees occlusion of the four limbs by 70 mm Hg relieved unpleasant symptoms. According to rheoencephalography, cerebral blood flow decreased to the level normally seen in the supine position. During a prolonged head-down tilting at an angle of -15 degrees intermittent occlusion of only lower limbs by 60--30 mm Hg proved more effective.

[Experimental evaluation of the relationship between lesser circulation engorgement, the state of water-salt metabolism and the orthostatic reactions in man]. / Eksperimental'naia otsenka sviazi mezhdu krovenapolneniem malogo kruga, sostoianiem vodno-solevogo obmena i ortostaticheskimi reaktsiiami u cheloveka

In 12 series of short-term (4.5 hour) experiments the exposures that influenced the blood distribution relative to the long axis of the body (postural changes, lower body excessive pressure, lower body negative pressure, axial loads) were studied. A close correlation between the blood flow in lung capillaries, water losses and orthostatic responses was established. The correlation was dysproportional when LBEP or LBNP was applied in certain postures. This may be attributed to the effect of these exposures on vessel compliance.

[Orthostatic stability in cosmonauts following 30- and 63-day flights in orbital station "Salyut-4"]. / Ortostaticheskaia ustoichivost' u kosmonavtov posle 30- i 63-sutochnykh poletov na orbital'noi stantsii "Saliut-4"

Reactions of the circulation system of cosmonauts to the up and down body movements were studied after 30-day and 63-day flights. All the four cosmonauts showed a decline in the orthostatic tolerance. An improved system of countermeasures against unfavourable effects of weightlessness used in the 63-day flight helped to maintain a better orthostatic tolerance of the crewmembers than that of the 30-day cosmonauts. It is assumed that a rapid increase of orthostaic tolerance postflight indicates an adequate maintenance of functional capabilities of circulation and suggests possible stimulation of its antigravity mechanisms prior to reentry in order to prevent postflight orthostatic disorders. An exposure to weightlessness increased the capacity of circulation to counteract the blood redistribution in the cranial direction in the head-down position. This capacity became more pronounced and stable with an increase in the flight time.