[Oxygen status and regional blood flow in the gingival mucosa as affected by lower body negative pressure]. / Kislorodnyi rezhim i regionarnyi krovotok slizistoi obolochki desny pri vozdeistvii otritsatel'nogo davleniia na nizhnuiu polovinu tela.

Five test subjects were exposed to lower body negative pressure (LBNP). During exposure their regional circulation and oxygen balance of the gingival mucosa were measured and electrocardiography and kinetocardiography were performed to calculate parameters of the left heart function. The study showed a distinct correlation between LBNP tolerance and the level of compensatory reactions of the gingival mucosa blood flow and the cardiovascular system as a whole. The subjects with a high LBNP tolerance showed well pronounced regional compensatory reactions of the gingival mucosa that were not accompanied by significant changes in the left heart function. The subjects with a moderate tolerance exhibited either weak or no regional compensatory reactions of the gingival mucosa and significant changes in the left heart function.

[LBNP test reactions of Salyut-5 orbital station crew members]. / Reaktsiia chlenov ékipazhei orbital'noi stantsii "Saliut-5" na probu s ODNT.

During the 49-day mission (first expedition) the Commander did not show a decline in LBNP tolerance, whereas the Flight-Engineer showed a progressive decrease in LBNP tolerance beginning with Mission Day 23. During the 17-day mission (second expedition) the Flight-Engineer exhibited greater cardiovascular reactions to LBNP than the Commander. Postflight examinations confirmed the observations made in the weightless state.

Pattern of blood circulation in the brain during rest and functional tests by Salyut-4 space crewmen.

Changes in the rheoencephalogram (REG) obtained for cosmonauts on the first and second expeditions during their time aboard the orbiting station, Salyut-4, are described. REGs were recorded by a small apparatus, Levkoi-3, with subsequent transmittal of the information to Earth stations. It was established that during flight under conditions of negative pressure on the lower half of the body (NPLHB), there was a decrease, in all cases, in pulse filling of brain blood vessels and an improvement in venous outflow from the cranial cavity. This indicates the efficiency of the compensation-adaptation reaction of the system studied to the state of weightlessness and the positive effect of prophylactic measures taken during flight. REG changes in indices affected by negative pressure were mainly such as were observed in preflight investigations, but there were individual differences. It was discovered that in all cosmonauts during performance of functional tests on a veloergometer, there was a significant increase in indices of pulse filling of brain blood vessels in response to muscle load in comparison with preflight studies. Normalization of basic REG indices took 3-7 min after the work was concluded. Planimetric analysis with REGs registered under conditions of long flight disclosed a variety of reactions of different sections of the vascular channels in the brain. Data obtained indicated the value of the REG method for making observations on crew members of space ships during orbital flights.