[Developing the methodology of examining the lower limb veins in cosmonauts for the space medicine practice].

The article centres on development of a methodology for evaluating the function of lower limb veins of cosmonauts in microgravity. The whys and wherefores of the choice of occlusive plethysmography equipment and procedure are explained. Much place is given to arguments for the requisite body and limb positioning during venous plethysmography pre launch and on return from space flight.

[Prediction of human orthostatic tolerance by changes in arterial and venous hemodynamics in the microgravity environment].

The authors intentionally present exclusively the results of their recent studies of arterial and venous hemodynamics as predictors of human orthostatic tolerance (OT) during space flight and on return to Earth. There is a sufficient demonstration of the in-flight OT predictability by arterial hemodynamic reactions to LBNP and venous hemodynamic changes in response to the lower extremities occlusion. Three levels of cerebral blood flow deficits in the course of the lower body negative pressure test (LBNP) performed in microgravity were first defined.

[The features of adaptation and disadaptation of the human cardiovascular system in the space flight conditions].

The work was aimed at analysis and generalization of the hemodynamic data collected over 20 years from 26 cosmonauts flown 8 to 438 days aboard orbital stations Salyut 7 and Mir. The paper presents the results of ultrasonic investigations of the heart, arterial and venous peripheral vessels in different parts of human body, and measurements of leg veins capacity with the use of occlusive plethysmograpy. It was shown that in the resting condition such prime hemodynamic parameters as the pumping function of the heart and blood supply of the brain, and integral parameters, i.

[Dynamics of human cardiovascular responses in different periods of long-term exposure in weightlessness].

Purpose of the work was to determine trends in the human cardiovascular function at rest and during LBNP in different periods of short- (8-25 d) and long-term (126-438 d) space flights (SF) using the data of USI and leg occlusive plethysmography. Due to blood redistribution and hypovolemia in the first week on SF, the cardiovascular system decreased the left heart filling and output without loss in myocardium contractility, weakened the renal artery resistance, and increased the maximum capacity of leg veins. In 30-40 days, these developments became more pronounced and were followed by a relative stabilization of hemodynamics at rest.

[The problem of artificial gravity: the present status and possible approaches].

The author reviews the Russian and international literature on the potentialities of artificial gravity in extended piloted space flights, especially in view of the declared initiatives to set forth on exploration missions in the first part of this century. Physical deconditioning and loss of tolerance to the gravitational loads consistently have their effects on cosmonauts despite the large assortment of in-flight preventive procedures. Effectiveness of artificial gravity generated by the short-arm centrifuge (SAC) has been assessed in experiments simulating the physiological consequences of microgravity by immersion or HDT, and flown aboard the dedicated satellites.