Biomedical subjects

S A Chupushtanov

Publications and source records attributed to S A Chupushtanov.

5 recordsLinked to original sources

PubMed2004

Mechanisms of the decrease in human postural stability during prolonged head-down tilt.

In 3 identical experiments with head-down bed rest lasting 60, 90, and 120 days and involving 18 volunteers, dynamics of the development of cardiovascular system (C.V.S) deconditioning was studied. A set of radioisotopic research techniques was used. Volumes of hemocirculation, body fluids, and metabolic activity of the bone marrow were investigated. Functions of the central and peripheral hemodynamics were studied. To determine the extent of C.V.S. deconditioning during the baseline period, on days 60, 90, and 120 of hypokinesia and during recovery, an orthostatic test was performed. The degree of gravitational blood shifting in regions (the head, thorax, the abdomen, the lower extremities) was recorded. Critical thresholds of blood shifting in the body were determined. It was established that the blood pooled in the splanchnic region participates in the decrease of central hypovolemia. Because of the insufficient number of observations, this research should be continued. During recovery, the sign of (CVS) deconditioning noted demonstrated a clear tendency to normalization.

Bed Rest↗

PubMed2000

The effect of a 14-day flight on body fluids in primates.

Using isotopes, two Bion 11 monkeys were examined 36 hours after flight. Total body water and all fluid compartments, particularly extracellular and interstitial fluid, were found to diminish. Blood volume and red blood cell mass also decreased. Forty-two days after flight, fluid compartments returned to normal. After the simulated flight, fluid compartments also tended to decrease but in a lesser degree than after real flight.

Animals↗

PubMed1998

[Methodologic aspects of body water kinetic dynamic studies].

In studying the level of hydration and liquid phases (LPs) in a space mission there use the stable and/or radioactive isotopes. The investigations are unique, the methods are adequate but not adapted in full measure to the challenges of the problem under study. The methodical approaches to the study of the dynamics of water metabolism are not available. Repeated introduction of the markers for these purposes is not acceptable. Another problem associates with taking the markers orally. In this case, a concentration of the markers will depend on the absorption and excretion processes. Prior to, during and in the readaptation period these functions will be different, making a correlation of the accumulated data difficult. There advances a possible version of solving these problems, namely, to use for the dynamic studies the residual contents of the markers in the LPs after single injection. However, this approach calls for investigating the kinetics of markers in weightlessness or during its ground-based simulation. The kinetics of tritium water has been studied in 6 volunteers under conditions of the 5-day bedrest and in 9 healthy men during free motor activity. There determined the characteristics of marker kinetics in a healthy man during his routine living activities. Under bedrest conditions there have been noted slowing-down of the rate and a decrease in the degree of marker accumulation in the body after its single injection, the shift of a period of relative stabilization of marker content in LP to the more late dates of experiment, slowing-down of the marker excretion rate from the body.

Adaptation, Physiological↗

PubMedDate not supplied

[Prevention of the adverse effects of head-down tilting on the infrastructure of body fluids and postural stability of primates by exposure to g-loads].

Experiments with 24 primates (Macaca mulatta) demonstrated that head-down tilting (-5 degrees) altered their hydration status as was manifested by a significant diminution of the amount of extracellular fluids, the interstitial fraction specifically. Blood circulation in leg muscles reduced almost in half In addition, return of the animals to the orthostatic position at the end of the experiment did not cause so intensive blood redistribution in leg vessels as in the group of tilted but not rotated animals.

Animals↗

PubMedDate not supplied

[Body fluids ratio and postural stability of head-down tilted apes in the periods of transition into the active vertical position].

It is known that the hypokinetic syndrome and alteration of the hydrostatic component by microgravity distort functioning of various body systems. Prevention of the adverse effects is achieved through implementation of a variety of physical exercises during tilting, and periodic transition into the upright position. The investigation was performed with 11 Macaques (Macaca mulatta) 3 to 5 yrs. of age and 3.2-7.2 kg of weight. Brief (for 30 to 120 min 4 or 5 times a wk.) transition into the active upright position had a positive effect on the body liquids ratio modification in the course of 27-d HDT (-5 degrees). This was concluded from a less pronounced loss in the amount of extracellular liquid and its interstitial component. In addition, another positive result of this manipulation was less, in terms of volume and speed, significant gravity-dependent blood flow toward the lower limbs during 10 minutes of standing test at the end of the experiment as compared with their controls w/o the preventive manipulation.

Animals↗