[Biochemical composition of a surfactant and its free radical processes in hyperbaric oxygenation and in the post-hyperoxic period]. / Biokhimicheskii sostav surfaktanta i svobodnoradikal'nye protsessy v nem pri giperbarooksigenatsii i v postgiperoksicheskii period.

Monitoring was made to examine the lungs. With this mode of hyperbaric oxygenation (0.3 MPa for 5 hours), rats developed mild oxygen intoxication which alleviated on day 3 and ceased on day 7 after its exposure. At the same time there were profound changes in the surfactant levels of protein, phospholipids, and cholesterol, which became normal on day 7 of postexposure. Chemiluminescence analysis and measurements of lipid peroxidation (PLO) products indicated that PLO rates in the surfactant decreased during hyperbaric oxygenation and remained at low levels within 24 hours of postexposure, whose cause might be activated by the antioxidative systems, as considered by the authors. However, on day 3 PLO enhances and on day 7 a new level of free-radical processes established, which was characterized by higher concentrations of free radicals and enhanced the activity of the antiradical systems.

[Free-radical processes in the lung tissue of rats under hyperbaric oxygenation and in the posthyperoxic period]. / Svobodnoradikal'nye protsessy v tkani legkikh krys pri giperbaricheskoi oksigenatsii i v postgiperoksicheskii period.

An increased antioxidation enzyme activity and a low level of the peroxidation products were revealed in exposure to low oxygen pressure and 1 to 7 days after it in rats. The data obtained suggest presence of a powerful antioxidant system in the rat lung.

[ATPase activity of subcellular rat brain fractions following hyperoxia]. / ATF-aznye aktivnosti subkletochnykh fraktsii mozga krys pri giperoksii

The total Mg2+-ATPase and Na+, K+-ATPase activity was studied in the fractions of "400 g X for 20 min" and "900 g X for 30 min" conditionally called the fraction of the external cellular membranes and total fraction of mitochondria. The subcellular fractions were isolated from great hemispheres and stem part of the rat brain. The brain of control animals and those during a severe spasmodic attact induced by the oxygen action at a pressure of 6 ati was studied. The total ATPase activity is established to be practically the same in the studied brain areas and unchanged with hyperoxia. Hyperoxia accompanying by convulsions results in an increase in the activity of Mg2+-ATPase and in a decrease in that of Na+, K+-ATPase both in the cerebral cortex and the stem part. The authors suppose that the decrease in the enzyme activity may occur due to an inhibitory effect on it of the lipids reoxidation products formed in the brain with hyperoxia.