[Tolerance of +Gx by MIR 22 -- 27 main crew in space flights]. / Perenosimost' peregruzok +Gx kosmonavtami 22-27-i ocnovnykh ékspeditsii orbital'nogo kompleksa "Mir" v kosmicheskikh poletakh.

Data on +Gx tolerance by 16 cosmonauts-members of the Mir 22-27 main crews in missions from 8 up to 380 days in duration are reported. All cosmonauts showed good tolerance of g-loads during insertion into orbit. Owing to the use of anti-g suit Centaur and water-salt supplements prior to deorbiting, tolerance of +Gx in the course of descent was satisfactory in the majority of the cosmonauts and low only in one person. As compared with short missions (8 to 21 days), strain of the physiological systems exposed to the deorbit +Gx loads following an extended period in microgravity (186 to 380 days) was greater and manifested by more often arrhythmias, hard breathing and speech, vestibulo-autonomous reactions, petechial hematomas into the back tegmentum, and more severe sinus tachycardia. As a rule, there were no symptoms indicative of poor g-tolerance (visual disorders etc.) which speaks for effectiveness of the anti-g measures in most of the cosmonauts. However, prognostically bad cardiac rhythm disturbances (multitude of single, group and systemic polytope ventricular extrasystoles) registered in one cosmonaut on the deorbit phase mean that efforts should be redoubled to improve countermeasures against the deconditioning of organism by microgravity, particularly the cardiac rhythm disturbances.

[G-tolerance of female cosmonauts during descent in space flights of 8 up to 169 days in duration]. / Perenosimost' peregruzok zhenshchinami-kosmonavtami na uchastke spuska v kosmicheskikh poletakh dlitel'nost'iu ot 8 do 169 sutok.

Investigations into g-tolerance of female cosmonauts during descent in space flights of varying duration are topical for the present day, as there are little data on this issue. Tolerance of +Gz-loads during descent was analyzed based on the data about 4 female cosmonauts in 5 space flights. The space flights were conventionally divided into short- (8-16 days) and long-term (169 days). In two space flights (16 and 169-d long), tubeless anti-g suit Centaur was warn during descent. In these space flights, g-tolerance of females was quite satisfactory advocating for the possibility for women to fly to space without any constraints. When the anti-g suit was not used, female physiological systems were stressed heavier than male. The spacesuit smoothed away this difference. Our results evidence a distinct positive effect of wearing the anti-g suit by female cosmonauts during descent as it reduces stress to their physiological systems.

[The effect of G-loads on gravity tolerance of monkeys Macaca rhesus during antiorthostatic hypokinesia]. / Vliianie gravitatsionnykh nagruzok v usloviiakh antiortostaticheskoi gipokinezii na gravitatsionnuiu ustoichivost' obez'ian makak rezusov.

Reported are results of 200 centrifuge runs of 24 monkeys Macaca mulatta. Microgravity effects were simulated by 4-wk immobilization with the head tilted down at -6 degrees. The investigation was divided into two series. During series-1, one group of animals was not exposed to centrifugal training, whereas the other group was exposed to +Gz at the magnitudes of 1.2, 1.4 and 1.6 G for 30-40 min 4 to 5 times a week. In series-2, again one group of animals was not trained on the centrifuge but the other was trained at +1.2 Gz for 30 min 2 or 3 times a week. Functional testing by 30-s runs at +3 Gz was performed before and after head-down immobilization. Deterioration of g-load tolerance following simulated microgravity in both groups of untrained macaques was ascribed to the deconditioning effect of simulated microgravity on the body systems. Centrifugal training had, as a rule, positive effect on g-tolerance of the animals though it failed to fully eliminate the negative consequences of simulated microgravity. This means that search after optimal protocols of application of artificial gravity generated by centrifuge needs to be continued. Evaluation of the effectiveness of combining centrifugation with other countermeasures against the adverse effects of microgravity and development of associated protocols can be another area of future research.

Muscle derived serum enzyme accumulation after +Gz acceleration test in Rhesus monkeys exposed to bed rest.

It is known that several hours of intensive muscle tension result in accumulation of muscle derived enzymes and structural proteins (see review by Clarkson, 1997). We have assumed that, firstly, acute exposure to hypergravity may induce accumulation of serum creatine phosphokinase (CPK), and, secondly, level of that accumulation may be considerably altered after long term hypokinesia.

Human +Gx tolerance with the use of anti-G suits during descent from orbit of the Soyuz space vehicles.

Previous investigations have shown the necessity of anti-G protection of cosmonauts on the stage of descent from orbit. Purpose of this research is to evaluate effectiveness of an elastic anti-G suits in opposing the descent accelerations in the Soyuz space vehicles.

[Human tolerance of +Gx loads in anti-G suits during deorbiting of the "Soiuz" space vehicles]. / Perenosimost' chelovekom peregruzok napravleniia +Gx na uchastke spuska s orbity kosmicheskikh korablei tipa "Soiuz" pri ispol'zovanii protivoperegruzochnykh kostiumov.

Reported are results of the study of tolerance of the "thorax-back" g-loads (+Gx) during deorbiting of 83 total suited and unsuited cosmonauts in the period of 1997-1997. G-loads averaged 3.7 +/- 0.058 units (from 3.1 up to 5.1 units). Pneumatic gradient G-suits (PGS) Karkas and Centaur had a positive effect on the +Gx tolerance of humans following microgravity. As compared with unsuited crews returning from missions of similar duration, wearing PGS has proven to improve the general health of cosmonauts and to reduce the strain of the leg and abdominal muscles. Tight fitting of PGS abolished visual disorders due to the longitudinal component of G-loads that were registered in 6.6% of observations of unsuited cosmonauts. Sinus tachycardia was significantly weaker (P < 0.05). The authors recommend the use of the standard antiblackout Centaur suit as the efficacy of this PGS was equal to that of Karkas while its ergonomic characteristics were superior.

[Tolerance of +Gz loads by space physician Poliakov VV during the active phases of his 438-days space mission]. / Prenosimost' peregruzok +Gx vrachom-kosmonavtom V.V. Poliakovym na aktivnykh uchastkakh kosmicheskogo poleta dlitel'nost'iu 438 sutok.

Tolerance of +Gz loads was assessed in space physician V.V. Polyakov during the active phases of his record, 438-day space mission. On the phases of insertion into orbit the +Gz-tolerance of the space physician was good; a fairly satisfactory g-tolerance during departure of orbit was extenuated by wearing of two anti-g suits (KARKAS-3 and CENTAUR) and administration of countermeasures against the unfavorable effects of space microgravity. His general health state and self-rating were not noticeably altered. +Gz loads in the course of descent from orbit instigated a syndrome characteristic of return to Earth from prolonged microgravity, i.e. a sensation of fierce pressure on the body, difficult breathing and speech, sine tachycardia, tachypnea, singular arrhythmias, petechial hemorrhage in the back integument, and vestibular/autonomous reactions. However, no evidence of any unusual physiological reactions that had never been seen in the other cosmonauts donned in the anti-g suits on earlier and less extended (from 65- to 366-day) missions were found. Extra systoles were registered on the phase of return to Earth after the 438-day but not previous 241-day mission of the space physician; they were probably associated with aging as he made his maiden flight at 47, and the second, at 53. The results speak in favor of the countermeasures against the adverse effects of microgravity applied during the mission, and the anti-g suits worn on the stage of return to Earth.

[Tolerance of +Gx-loads by females before and after a 120-day hypokinesia]. / Perenosimost' peregruzok napravleniia +Gx zhenshchinami do i posle 120-sutochnoi gipokinezii.

The goal of the work was to study female tolerance of g-loads before and after simulated weightlessness, and evaluate the effectiveness of countermeasures and anti-g means proposed for space flight. Centrifuge with a 7.25 m arm was used for 29 runs of 8 female subjects. The subjects were exposed to the transverse loads (+GX) at 8.2 g on a special regimen with the total run time of 9 min to simulate the ballistic descent from orbit in a SOYUZ-TM vehicle. Baseline tolerance of the females to transverse loads up to +8GX was good and satisfactory. Following 120 days of bed rest without the countermeasures or the anti-g suit g-tolerance was significantly lowered as evidenced by visual disorders in 67% of cases and exaggerated, if compared with the pre-hypokinesia levels, heart and respiration rates, i.e. 20% and 23.5%, respectively. The countermeasures and anti-g suit Centaur maintained g-tolerance at essentially the baseline level and precluded visual disorders. Results of the study speak in favor of the countermeasures and anti-g means used by the females in simulated long-duration weightlessness which can be recommended for the final phase of extended space mission.

Study of the effectiveness of the "Centaur" anti-G suit [correction of suite] during exposure to +Gz accelerations after immersion.

NASA: This paper describes a study of the effectiveness of the "Centaur" anti-G suit during exposure to +Gz accelerations before and after immersion. Results indicated that the subjects were better able to tolerate the acceleration using the "Centaur" suit than in control studies. Specific cardiovascular responses are presented. This suit has also been used successfully during space missions.^ieng

[Human equilibrium under conditions of rotation with different levels of increased weightiness]. / Funktsiia ravnovesiia cheloveka v usloviiakh vrashcheniia pri razlichnykh urovniakh povyshennoi vesomosti.

This paper discusses the gravity (of up to 2 g) effect on the upright stability of 16 test subjects exposed either to centrifugation or to artificially increased body weight (with uniformly distributed loading). During centrifugation the stabilographic parameters increased significantly at every gravity level. In the experiments with artificially increased body weight the area of the vector stabilograms also increased significantly. The comparison of the two experimental runs suggests that disorders in the upright stability are caused by the rotation factor rather than by the artificially increased body weight.

[Effectiveness of the preparation Gavinton in preventing motion sickness]. / Effektivnost' preparata kavinton v profilaktike bolezni dvizheniia.

The effectiveness of the Hungarian drug kavinton used to prevent motion sickness was assessed. During the study 8 motion sickness susceptible test subjects were kept in a chamber rotating at a rate of 6 rpm for 5 hours. The effectiveness of the drug taken regularly during the exposure was compared with that of scopolamine and placebo taken as a single dose. The results obtained are suggestive of a positive effect of kavinton as an antimotion drug.

[Human tolerance to rotation at different levels of increased gravitation]. / Perenosimost' chelovekom vrashcheniia pri razlichnykh urovniakh povyshennoí vesomosti.

The effects of acceleration of different value (up to 2 g) on the level of motion sickness, vestibular and postural reactions to rotation were studied. The experiments were carried out in a centrifuge equipped with a cabin that could be mounted at a different distance from the axis of rotation. Three experimental runs were conducted with a rate of rotation of 15.3 and accelerations values of 1.09, 1.6 and 2.0 g. Vestibular stimulation was produced by head movements of a predetermined number. It was found that with increase in the acceleration value the level of motion sickness decreased and the nystagmic reaction and balance dysfunction enhanced.

[Effect of head-down tilt hypokinesia on human equilibrium function]. / Vliianie antiortostaticheskoi gipokinezii na funktsiiu ravnovesiia cheloveka.

Six test subjects who participated in 182-day head-down study at -4 degrees were examined stabilographically before and during the test. During the first 30 days they showed impaired equilibrium which later was relatively stabilized. Continuation of the bed rest study did not impair drastically stability of upright standing. It was shown that the contribution of optic sensors into the recovery of the equilibrium function increased during the second half of the bed rest study. Provocative tests suggest that bed rest related impairment of equilibrium occurs due to vestibular changes and deconditioning.

[Subcellular changes in the cortex of the motor analyzer and hippocampus of dogs with locally manifested neuroses]. / Subkletochnye izmeneniia v kore dvigatel'nogo analizatora i gippokampa sobak pri nevroze s lokal'nym proiavleniem.

In experiments on dogs with local neurosis-continuous flexion of the foreleg-changes were revealed in the beta-rhythm amplitude and the frequency of mean unit activity in the motor cortex, and the appearance and increased amplitude of the theta-rhythm in the hippocampus. Specific activity of Na+-K+-activated, and Mg2+-dependent ATPase decreases in subcortical fractions of the experimental animals' cerebral cortex by 55.0% in the synaptic membranes and 2 to 2.5 times in light and heavy synaptosomes, respectively. In similar fractions of the dorsal hippocampus, the activity of the enzyme decreases by 30.0% in the synaptic membranes and increases by 16.6% in the light synaptosomes and by 6.6% in the heavy ones.