Measurement of the partial oxygen pressure and oxygen utilization in the skin of cosmonauts aboard Salyut 6.

The oxygen tension (PO2) in the dorsal skin surface of the forearm was studied during the stay of cosmonauts on board Salyut 6. Between the fourth and fifth day of stay on the orbital station a considerable reduction of the PO2 level was observed. The oxygen utilization values were also reduced.

[Types of spike activity and nature of neuronal interrelations in the rat neostriatum].

Statistical methods were used to study types of background activity (BA) of neostriatum neurons. Dependence of the crosscorrelation function on the BA type and on a distance between the neurons was examined in acute experiments on rats (one group was immobilized with d-tubocurarin, the other was under nembutal anesthesia). It is shown that BA according to the shape of the autocorrelation and crosscorrelation functions can be classified into five types (I.

[Oxidation of sulfide minerals by Thiobacillus ferrooxidans].

Samples of natural pyrites and sphalerites were subjected to the action of the mineral medium 9K with 1 g of Fe3+ per litre in the presence and in the absence of Thiobacillus ferrooxidans, and incubated at 28 degrees C under the stationary conditions for 30 days. The chemical composition of the solutions was studied after leaching as well as changes of the surfaces of monoliths. The deepest etching of surfaces with the formation of crusts and films of jarosite, limonite and goslarite occurs upon the combined action of bacteria and Fe3+ in regions of a fine-zonal structure enriched with an isomorphous arsenic admixture which are characterized by a defective weak structure.

[Characteristics of the formation of human cardiovascular system reactions to acute hypoxia].

"Emergency" adaptation of the cardiovascular system of a healthy person to acute hypoxia produced by inspiration of a gas mixture containing 11% oxygen was accomplished in two ways: (a) with prevalence of the cardiac component, increase in the cardiac and systolic indices and end-diastolic volume in unaltered ejection fraction and diminished general vascular tonus; (b) with prevalence of the vascular component, decrease in the cardiac and systolic indices, end-diastolic volume, and muscular and skin blood flow and increase in peripheral resistance. After 10 days of training for hypoxia in a pressure chamber the reaction of the cardiorespiratory system to the hypoxia test was less pronounced but its trend was maintained.

[State of the temporal organization of the system of cell reproduction in rat tissues under hypokinesia].

The study of time parameters of cell kinetics in the rats exposed to 34-day hypokinesia showed that changes in cell reproduction developed in rapidly and slowly renovating cells in a different way. The DNA synthesis and mitotic division were drastically inhibited in liver cells; the duration of the premitotic period of the mitotic cycle was significantly reduced in the cryptal epithelium of the small intestine. Hypokinesia did not cause important changes in the phasic structure of diurnal rhythms of cell division in the tissues tested and, consequently, did not lead to changes in the mechanisms of time organization of the cell reproduction system.

[Chief methods of modeling the biological effects of weightlessness].

The paper describes basic principles related to weightlessness simulation. In ground-based experiments zero-g is simulated with respect to the conceptual mechanisms of weightlessness effects on the body. The main components of the effects are considered to be elimination of deformations and fluid redistribution.