[Dynamics of ECG voltage in changing gravity].

Comparative analysis of the QRS voltage response to gravity variations was made using the data about 26 normal human subjects collected in parabolic flights (CNERS-AIRBUS A300 Zero-G, n=23; IL-76MD, n=3) and during the tilt test (head-up tilt at 70 degrees for a min and head-down tilt at-15 degrees for 5 min, n=14). Both the parabolic flights and provocative tilt tests affected R-amplitude in the Z lead. During the hypergravity episodes it was observed in 95% of cases with the mean gain of 16% and maximal--56%. On transition to the horizontal position, the Rz-amplitude showed a rise in each subject (16% on the average). In microgravity, the Rz-amplitude reduced in 95% of the observations. The voltage decline averaged 18% and reached 49% at the maximum. The head-down tilt was conducive to Rz reduction in 78% of observations averaging 2%. Analysis of the ECG records under changing gravity when blood redistribution developed within few seconds not enough for serious metabolic shifts still revealed QRS deviations associated exclusively with the physical factors, i.e., alteration in tissue conduction and distance to electrodes. Our findings can stand in good stead in evaluation of the dynamics of predictive ECG parameters during long-term experiments leading to changes as in tissue conduction, so metabolism.

[Reactions of the human bone system in space flight: phenomenology].

Results of multi-year bone observations in crewmembers of long-term (6 to 14 mos.) Salyut and Mir missions have been summarized. The theoretical expectation of bone losses (mineral bone density, MBD) was consistent only in the trabecular of the lower skeleton (lumbar spine, femur proximal epiphysis, pelvis). The upper skeleton bones (skull, cervical spine) demonstrated a clears-defined trend toward an increase in mineral content. There is a direct dependence of MBD losses on a skeleton bone position relative to the gravity vector and bone structure. Post-flight MBD did not, as a rule, deviate from the WHO-defined limits (T-criterion); in several instances MBD loss was qualified as local osteopenia. Shifts in MBD, same as MBD recovery rate, vary with subjects and, therefore, deny their dependence on flight duration. By and large, MBD shifts are interpreted as a functional adaptation of bone tissue to changing mechanic demands.

Selection and biomedical training of cosmonauts.

NASA: The first cosmonauts were selected from the flying personnel. These individuals enjoying good health were more familiar with the conditions and effects of the factors similar to those which are to be found in space missions. In future, because of the complication of tasks to be solved in space missions, an inflight utilization and testing of sophisticated space technology, and conducting a broad spectrum of scientific studies, a demand arose for including cosmonaut-researchers--highly qualified representatives of various scientific specialities--in a flight crew. In this connection, a necessity was created for changing some evaluation criteria to assess the health status of the chosen candidates considering their age and physical fitness. In specific cases, during the selection process some health-improving measures related to professional significance of the candidates for a position of cosmonaut-researcher was carried out. The prime goal of cosmonauts selection is to predict their good tolerance for a particular space mission while maintaining health and adequate performance throughout the flight, completing the flight tasks and assuring successful return to the Earth. Inclusion of cosmonaut-researchers in space crews requires study of an effect of spaceflight factors on reactions of female subjects in simulated ground-based investigations. At present, the preparation of cosmonauts, can be defined as a continuous purposeful process of training, forming and maintaining operational skills, bringing up the crewmembers to acquire professionally significant psychological and physical features essential for effective work to be done in space mission. The preparation of cosmonauts consists mainly of technical, aviation and space, medical-biological and scientific trainings.^ieng

Development of U.S.-Russian medical support procedures for long-duration spaceflight: the NASA-Mir experience.

As the Russian Space Agency and the U.S. National Aeronautics and Space Administration began in the mid-1990s to plan a preliminary cooperative flight program in anticipation of the International Space Station, programmatic and philosophical differences became apparent in the technical and medical approaches of the two agencies. This paper briefly describes some of these differences and the process by which the two sides resolved differences in their approaches to the medical selection and certification of NASA-Mir crewmembers. These negotiations formed the basis for developing policies on other aspects of the medical support function for international missions, including crew training, preflight and postflight data collection, and rehabilitation protocols. The experience gained through this cooperative effort has been invaluable for developing medical care capabilities for the International Space Station.

[Bone mineral density in cosmonauts after flights lasting 4.5-6 months on the Mir orbital station]. / Mineral'naia plotnost' kostnoi tkani u kosmonavtov posle poletov dlitel'nost'iu 4,5-6 mesiatsev na orbital'noi stantsii "Mir".

A technique of quantitative digital roentgenography (QDR) being a current modification of dual photon absorptiometry (DPA) was used to measure bone mineral density (BMD) in the crewmembers of the 6-9th expeditions onboard Mir orbital station after space missions of 132 to 176 days in duration. Total mineral losses were, on average, 0.4% of a preflight level, and in the most test subjects the postflight BMD of the skull, ribs and arms increased and that of lumbar vertebrae, pelvis and legs decreased. The most marked local postflight mineral losses occurred in the proximal femur bone (the femoral neck and the greater trochanter--up to 14%). The observed changes did not depend on flight duration. These findings are being compared to the results of similar studies conducted during the 120-day (NASA) and 370-day (IBMP) hypokinesia experiments. The possibility of existing the general mechanism of modifying mineral status of the skeleton due to different situation related deficiency of musculoskeletal load.

[Clinical and physiological evaluation of bone changes among astronauts after long-term space flights]. / Kliniko-fiziologicheskaia otsenka izmenenii kostnoi tkani u kosmonavtov posle dlitel'nykh kosmicheskikh poletov.

Results of the joint Russian/US studies of the effect of microgravity on bone tissues in 18 cosmonauts on return from 4.5- to 14.5-month long missions are presented. Dual-energy x-ray gamma-absorbtiometry (QDR-1000 W, Hologic, USA) was used to measure bone mineral density (BMD, g/cm2) and mineral content (BMC, g) in the whole body, the scalp including cervical vertebra, arms, ribs, sternal and lumbar regions of the spinal column, pelvis and legs. A clearly defined dependence of topography of changes upon the position of a skeletal segment in the gravity vector was established. The greatest BMD losses have been observed in the skeleton of the lower body, i.e. in pelvic bones (-11.99 +/- 1.22%), lumbar vertebra (-5.63 +/- 0.817%), and in proximal femur, particularly in the femoral neck (-8.17 +/- 1.24%). Bones of the upper skeleton were either unchanged (insignificant) or showed a positive trend. Overall changes in bone mass of the whole skeleton of male cosmonauts during the period of about 6 months on mission made up -1.41 +/- 0.406% and suggest the mean balance of calcium over flight equal to -227 +/- 62.8 mg/day. Reasoning is given to qualify these states of cosmonauts' bone tissues as local osteopenia. On the literature and results of authors' clinical evidence, discussed is availability of the densitometric data for predicting risk of trauma. A biological nature of the changes under observation is hypothesized.

Changes of corticosteroid spectrum in urine in members of crew of spaceship "Soyuz-22".

The urinary excretion of 17-hydroxycorticosteroids and the relations between the glucocorticoids in urine and their precursors as well as between 17-hydroxycorticoids and 17-hydroxycorticoids and 17-dehydroxycorticosteroids was measured in two subjects before and after 8 days flight in spaceship "Soyuz-22". During a readaptation period after the space flight activation of the glucocorticoid function of adrenals was observed which was accompanied by signs of stress and relative deficiency of 11-hydroxylation in glucocorticoid synthesis. The assumptions on possible causes of observed changes are discussed.

[Biochemical status of adrenocortical dysfunction after space flight]. / Biokhimicheskii status adrenokortikal'noi disfunktsii posle zaversheniia kosmicheskogo poleta.

Renal excretion of 17-HOCS and aldosterone as well as the ratio of excreted glucocorticoids and their precursors was investigated in the Soyuz-31 Commander before and after his 7-day flight. Renal excretion of total 17-HOCS remained unchanged while hydroxylation in positions 11 and 17 in the course of corticosteroid synthesis was relatively deficient.

[Model of the perception of perturbed angular motion of the cockpit as part of pilot's information model]. / Model' vospriiatiia pilotom vozmushchennogo uglovogo dvizheniia kabiny kak chast' ego informatsionnoi modeli.

This paper presents the method, algorithm and results of structural identification as a model of pilot's perception of perturbed angular motion of the cockpit and its transmission to the joystick as well as spectral density of the remnant corresponding to the transmission process. Assessments of scalar quasilinear and (more effective) multichannel models of pilot's functions are given. The assessments have been obtained for a single operator. They illustrate the potentials of this procedure.

[Results of endocrinologic studies of the 3d international crew of the scientific orbital station complex: Soyuz 29 - Salyut 6 - Soyuz 31 (joint space flight enterprise of the USSR - GDR). 3. Corticosteroid excretion in urine]. / Ergebnisse endokrinologischer Untersuchungen bei der 3. internationalen Besatzung des wissenschaftlichen Orbitalkomplexes Sojuz 29 - Saljut 6 - Sojuz 31 (gemeinsames Raumflugunternehmen UdSSR - DDR) 3. Mitteilung: Die Kortikosteroidausscheidung im Urin.

In the present study the attempt was made to evaluate the functional state of the adrenal cortex after space flight by means of the urinary corticosteroid content. The urine collected over 24 hours was analysed. The following parameters were determined: Total 17-hydroxycorticosteroids (17-OHCS), their free forms, glucuronides and sulphates; cortisol (F), cortisone (E), corticosterone (B), 11-desoxycortisol (S), 11-dehydrocorticosterone (A), tetrahydrocortisol (THF), tetrahydrocortisone (THE), tetrahydrocorticosterone (THB), tetrahydro-11-desoxycortisol (THS), and aldosterone. In order to characterize the activity of the 11-hydroxylase the quotient of THS + S/THF + F + THE + E was formed. The activity of the 17-hydroxylase was determined indirectly by the quotient of THF + THE + THS + F + E + S/THB + B + A = 17-OHCS/17-DOHCS. The expected distinct increase of the 17-OHCS after the space flight failed to appear. This finding may be due to an adrenocortical dysfunction. In the space ship commander the quotients indicate a reduced 11- and 17-hydroxylation during the process of synthesis of the glucocorticoids. In the flight engineer they give evidence of an unchanged biosynthesis except on the day of landing. A hitherto not fully intensified substance ("white spot") was found in the chromatogram of the space ship commander on the first and second day after the flight. Moreover, the investigations show that the reaction of the adrenal cortex after space flights exhibits a number of individual characteristics.

[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.

[Results of endocrinolgic studies of the 3rd international crew of the scientific orbital station complex; Soyuz 29 - Salyut 6 - Soyuz 31 (joint space flight enterprise of the USSR - GDR). 2. Hormones and biologically active substances in blood]. / Ergebnisse endokrinologischer Untersuchungen bei der 3. internationalen Besatzung des wissenschaftlichen Orbitalkomplexes Sojuz 29 - Saljut 6 - Sojuz 31 (gemeinsames Raumflugunternehmen UdSSR - DDR) 2. Mitteilung: Hormone und biologisch aktive Stoffe im Blut.

Cortisol, insulin, somatotropin, thyreotropin, thyroxine, triiodothyronine, testosterone, aldosterone, c-AMP, c-GMP, prostaglandins (PGF1-x, PGF2-x, PGA + E), and renin concentrations in serum or plasma of the venous blood of the third international crew of the scientific orbital complex of "Soyuz 29 - Salyut 6 - Soyuz 31" were determined following the 7-day space flight. The increased activity of the renin-angiotensin-aldosterone system before the flight as well as variations in the pressor/depressor prostaglandin ratios indicate an increased strain during the pre-flight period. During the first stage of the post-flight period some parameters were changed due to the landing process and the returning to earth gravity. The associated physical load and the onset of reactions for enhancement of the orthostatic tolerance resulted in an increase of cyclic nucleotid and thyroxine concentrations. The relatively higher levels of the pressor PGs of group F in comparison with the prostaglandins A + E could be evaluated as a compensatory reaction for enhancement of the orthostatic tolerance. The cortisol and STH concentrations increased with growing motor activity. The variations seen after the 7-day space flight were essentially within the reference areas. It may be assumed that the readaptation was not yet totally accomplished by the 8th day after landing.