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Biomedical subjects

A R Kotovskaia

Publications and source records attributed to A R Kotovskaia.

At least 19 recordsLinked to original sources
PubMed2003

[Effects of centrifugation-related artificial gravity on the human organism. Positive and negative effects].

Data of investigations of the artificial gravity issues in centrifuge experiments in Russian, USA and Japan over the past 40 years were analyzed. Periodic +Gz centrifugation was used to prevent or eliminate body deconditioning after 3- to 56-d simulated microgravity, and to increase the body functional reserve (orthostatic stability) in ordinary life. Positive effects included prevention of a decline of gravitational stability and reduction or averting the negative effects of simulated microgravity on various physiological systems. Better results can be achieved by combining artificial g-loads with the well-proven methods of combating deconditioning, i.e. physical training on bicycle ergometer and induced hydration. Human tolerance of g-loads on a short-arm centrifuge with a high (100%) gravitational gradient was found no worse than on a mid-arm centrifuge with a lower (20%) gravitational gradient. Negative effects of +Gz on a short-arm centrifuge were revealed and counteracting measures were determined.

Centrifugation↗
PubMed2003

[The problem of creation of artificial gravity with the use of a short-radius centrifuge for medical support of interplanetary piloted missions].

On the evidence of orbital flights, the system of countermeasures against the effects of microgravity does not fully make for deconditioning of a number of human organs and systems and recovery of preflight physical status and working ability of members of long-term missions takes 1.5 to 2 mos. of the post-flight rehabilitation. In order to maintain the physical form, health and performance of crews in future interplanetary missions, we should be ready to offer them a novel countermeasure, i.e. regular sessions of artificial gravity generated by a short-radius centrifuge (SRC) on board vehicles. The articles presents the substantiation and concept of ground-based simulation studies of health benefits from SRC in interplanetary missions. Of primary concern is development of SRC regimens that will put up a strong opposition to microgravity, assure crew safety, and reduce to the minimum time to fulfill the in-flight countermeasure program. Answers to arising questions can be found by consolidation of the expertise and resources of the countries willing to meet this challenge.

Adaptation, Physiological↗
PubMed2001

[Tolerance of +Gx by MIR 22 -- 27 main crew in space flights].

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.

Adult↗
PubMed2001

[The effect of G-loads on gravity tolerance of monkeys Macaca rhesus during antiorthostatic hypokinesia].

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.

Adaptation, Physiological↗
PubMed2001

[G-tolerance of female cosmonauts during descent in space flights of 8 up to 169 days in duration].

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.

Adaptation, Physiological↗
PubMed2000

[Technique for registration of auricular pulsogram in macaca mulatta monkeys].

An upgraded technique for registration of auricular pulsogram in monkeys (Macaca mulatta) has been proposed to study shifts in the common artery bed. The measurement is made with a photo-electrical sensor taped to the cartilage of the floor of the auricle and secured with a special cap and helmet of elastic net, and a system for data transfer from the sensor to a register enhanced by preamplifiers. Potentialities of the technique are exemplified by the investigation of Macaca mulatta's tolerance of +Gz loads.

Animals↗
PubMed1998

[Role of age in +Gz and +Gx tolerance by female candidates to astronauts].

Analyzed was the role of age in the tolerance of +Gz (up to 5 units) and +Gx (up to 8 units) by female candidates to cosmonauts on the stage of initial centrifuge selection in the years of 1979 through to 1993. Selection was made of 26 healthy non-flying women aged 23 to 39 who were divided into 4 groups with 5-year intervals. Female tolerance of g-loads and shifts in a number of physiological parameters during centrifugation were discovered to be age-dependent. The poorest tolerance of +Gz and +Gx loads was typical of women below 25 years, the best, at the age of 31 to 40 years. It was stated that tolerance of these demanding g-loads by women, especially below 30, was generally worse compared with men. There were also some distinctions in the cardiovascular response in women and men. These results point to the significance of centrifugation in selection female candidates to cosmonauts irrespective of their age.

Adult↗
PubMed1998

[Human tolerance of +Gx loads in anti-G suits during deorbiting of the "Soiuz" space vehicles].

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.

Astronauts↗
PubMed1997

[Tolerance of +Gz loads by space physician Poliakov VV during the active phases of his 438-days space mission].

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.

Adaptation, Physiological↗
PubMed1997

[Tolerance of +Gx-loads by females before and after a 120-day hypokinesia].

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.

Adaptation, Physiological↗
PubMed1995

[The Jupiter-2 slow-rotation system].

The experience of space missions shows that functional disorders in crewmembers on the type of space motion sickness (SMS) may develop on the initial stage of flight. Longer exposure in micro-g causes a wide range of debilitative changes in the vital body systems. Artificial gravity produced by spacecraft rotation might be a universal tool to counteract the impacts of prolonged microgravity on the human body. However, the significance of SMS does not become less high because of a new factor, i.e. the rotating environment. Research system Jupiter 2 is a stand-alone slow-rotating ground facility for simulating motion sickness equivalent to its space form. The merits of this facility are the possibilities to control the intensity of exposure, perform long-term investigations of two active subjects simultaneously, and study the stages of body adaptation to this agent, and assess physical and operator's performance. The facility carries large expectations to occupational selection.

Equipment Design↗
PubMed1995

[Dynamics of tolerance of +G loads by non-flying subjects: a longitudinal study].

Selected cosmonauts-investigators may be held on wait for many years. The longitudinal health study is of great significance in the context of prediction of tolerance to various flight stresses. The purpose of this work was to investigate the tolerance to +Gz-loads during extended (up to 18 years) dynamic longitudinal study of 50 male cosmonauts and candidates of non-flying occupations by the data of 363 medical observation runs on a centrifuge with the radius of 7.25 m. Analysis of these data showed that 82 % of the subjects sustained good tolerance of G-loads and only 18 % of the subjects displayed its decrement or instability. A new proof received the data concerning better +Gz-tolerance by subjects aged 31-35 and less tolerance by the subjects younger than 30 and older than 46-50 years. The longitudinal study allowed to identify 4 types of G-tolerance variation, i.e., stable, relatively stable with individual drops down to decreased, non-stable with periodic drops, and a distinct trend towards a decrease. These investigations provided new scientific data about the dynamics of separate physiological functions during exposure to +Gz-loads resultant from longitudinal study of the same group of subjects, and allowed to make an expert prediction of shifts in the G-tolerance.

Adult↗
PubMedDate not supplied

[An experimental validation of pharmacological agents to arrest the vestibulo-autonomic syndrome (motion sickness)].

The results of development and experimental evaluation of the efficiency of pharmacological means of cupping the vestibulo-vegetative syndrome in man are presented. A model and procedure of evaluation of pharmacological cupping of the Vestibulo-vegetative syndrome are developed. The intramuscular injection of the mixture containing ephedrine, promethazine hydrochloride and strychnine (25, 50, and 1 mg, respectively) appeared most effective.

Coriolis Force↗
PubMedDate not supplied

[Informativeness of pulse bloodfilling of auricular helical vessels for evaluation of human tolerance to plusGz acceleration].

The possiblity of using photoelectric plethysmography as an objective method to assess the human tolerance to accelerations was examined. The tolerance of 40 young healthy male test subjects to plus GZ accelerations of 3, 5, 6 and 7 g with an increase gradient of 0.4 g/sec and a plateau time of 30 sec was measured. The test subjects induced an arbitrary tension of the abdominal and leg muscles in order to better tolerate accelerations. When the tolerance reached its limit (as judging by optic disorders), the auricular pulse amplitude decreased 4-fold in 84% test subjects. The threshold value of the amplitude can be used as an informative indicator of a group and individual tolerance to plus GZ accelerations. A portable photoelectric plethysmograph has been designed for operational medical control of the health state of pilots inflight.

Acceleration↗
PubMedDate not supplied

[Human tolerance to +Gz acceleration during heating].

Eighty-six measurements of individual tolerance of 25 healthy test subjects to +Gz accelerations were carried out at two body temperatures. At moderate heating (body temperature 37.5+/-0.2degreesC) acceleration tolerance decreased by 1.4 g (maximally by 3 g) without an antigravity suit and by 0.5 g with an antigravit suit. In case of simulated poor fitting of the suit the tolerance decrease was 1.1 g. At high heating (body temperature 38.0+/-0.2degreesC) the decrease was great (2.1 g). In some cases centrifugation was terminated because of poor tolerance to hyperthermia. The regression analysis suggests that at body temperature of 37.3degreesC the acceleration tolerance decreases in some individuals only and at 37.6degreesC and over it declines in most subjects. The correlation between the level of water losses (0.8--2.4% of body weight) and decline in +Gz tolerance was low (r=0.33) and insignificant. The resulting data allow practical recommendations in relation to acrobatic flights in hot climate.

Acceleration↗