[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.

[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.

[Oxygen balance and regional blood flow in the gingival mucosa during exposure to head-pelvis (+Gz) acceleration]. / Kislorodnyi rezhim i regionarnyi krovotok tkanei slizistoi obolochki desnypri vozdeistvi peregruzki golova - taz (+Gz).

The information content of a new contact rheopolarographic procedure used to determine the oxygen balance and regional circulation of the gingival mucosa was measured, bearing in mind the applicability of the procedure as an objective index of human tolerance to +Gz acceleration. It was found that the parameters of the oxygen balance and regional circulation of the gingival mucosa were well correlated with blood pressure in the floor of the auricle. In contrast to the traditional methods for assessing tolerance to acceleration, the new procedure provides information about the health condition of the centrifuged subjects on a continuous basis. Variations in the oxygen balance and regional circulation of the gingival mucosa helped to identify compensatory reactions of the cardiovascular system in response to +Gz acceleration.