[Oxygen-dependent processes in the irradiated organism]. / Kislorodzavisimye protsessy v obluchennom organizme.

Interaction of oxygen with the X-rayed tissues, chemical substances and elements is one of the main mechanism of radioactive damage. Radiosensibilization by oxygen (oxygen effect) is most highly exhibited under the action of high and moderate radiation doses. However there is only scanty investigations and information about oxygen-dependent processes under low doses of internal and external radiation due to their intricate character. Radiation exerts also a great influence on oxygen metabolism and oxygen consumption level. Oxygen takes active part in post-radiation recovery both at the level of molecules, organelles, cells, tissues, organs and the organism on the whole. The partial pressure of oxygen and its content have a great influence on the action of radioprotectors, anti-radiation therapy and healing methods. Long-term influence of hypoxia at high altitude evokes adaptation changes, stimulates recovery processes in an X-rayed organism, increases resistance to radiation and other noxious factors.

[Effect of ethanol and ethylene glycol on the circadian rhythm of adenylic nucleotide levels in muscles]. / Vliianie étanola i etilenglikola na sutochnyi ritm soderzhaniia adenilovykh nukleotidov v myshtsakh.

The 24-hour's changes in ATP content in the gastrocnemiuses of intact rast are not significant. Both the ADP and AMP content is subjected to 24-hour's variations. It reaches its maximum within the time period from 12 to 15 o'clock p.m. for ADP and at 18 o'clock p.m. for AMP. Intragastric administration of ethanol and ethylene glycol to rats in a dose of 1/3 LD50 once per 24-hour period at 9 a. m. during a 7-days-long period dramatically changes the 24-hour's rhythm of adenylic nucleotide content in the rat gastrocnemius. It has been found that ethanol increases the average 24-hour's content of ATP, but decreases that of ADP. It increases the range of their 24-hour period variations and changes the acrophase. Ethylene glycol decreases the average 24-hour content of the both ATP and ADP, but it increases that of AMP. It changes their acrophases and increases the ranges of 24-hour-period variations of ATP.

[Membrane potential of muscle fibers exposed to corticotropin and hydrocortisone]. / Membrannyi potentsial myshechnykh volokon pod vliianiem kortikotropina i gidrokortizona.

The effect of a single intraperitoneal administration of corticotropin (1 unit) and hydrocortisone (5 mg) per 100 g of a body weight on the membrane potential (MP) as well as on the response rate of miniature end plate potentials (RRMEPP) of musculus soleus fibres of various polarization levels has been investigated in rats. It is shown that administration of corticotropin does not change the MP value, while that of hydrocortisone elicits its increase at the low initial polarization level of the muscle fibre membrane and its decrease at the high level. Hydrocortisone administration does not change the MP value at normal levels of fibre polarization. Corticotropin having been administered, RRMEPP of fibres both with high MP levels and with low ones has increased. Fibres with normal polarization also show a tendency to increase. Administration of hydrocortisone has induced a substantial increase of RRMEPP in fibres with high polarization levels within 45 min, while PRMEPP of fibres with normal polarization levels increased within first 5 min., and that of fibres with low levels of polarization remained unchanged.

[The embryotoxic effects of monohydric alcohols]. / Embriotoksicheskie éffekty nekotorykh odnoatomnykh spirtov.

We have compared the embryotoxic effect of aliphatic alcohols on antenatal embryogenesis of rats and the activity of alcohol dehydrogenase (EC.1.1.1.1) in embryonic hepatocytes. The embryotoxic activity of the used alcohols in equitoxic doses (assessed as the lethal effect) showed some dependence on their chemical structure. Earlier it has been demonstrated that there is a similar dependence for the mutagenic effects of the alcohols at the chromosomal level. All tested compounds, with the exception of decanol, distinctly retarded the development, but did not exert any teratogenic action. The administration of aliphatic alcohols also led to a significant decrease in the activity of alcohol dehydrogenase in fetal hepatocytes.

[The effect of alcohols on daily variations in aspartate amino- transferase activity in rat organs]. / Vliianie spirtov na sutochnye kolebaniia aktivnosti aspartataminotransferazy v organakh krys.

The 7 day-long intragastric administration of ethanol and ethyleneglycol in a dose of 1/3 DL50 was studied for its effect on the circadian variations of the aspartate aminotransferase activity (AST, EC 2.6, 1.1) in the liver, brain, myocardium and kidney of male rats. The ethanol and ethylene glycol administration reduced the mean circadian enzymic activity in the above organs. Moreover, ethanol significantly reduced the amplitude of circadian variations of the AST activity in the liver, brain and kidney, while ethylene glycol--in the liver, myocardium and kidney.

[Effect of corticotropin and hydrocortisone on carbohydrate metabolism in skeletal muscles]. / Vliianie kortikotropina i gidrokortizona na uglevodnyi obmen v skeletnykh myshtsakh.

The intraperitoneal administration of corticotropin (ACTH) in the rate of 1 and 2 units per 100 g of body weight and that of hydrocortisone in the rate of 1 mg and 5 mg per 100 g body weight were studied for their effects on carbohydrate metabolism rate in musculus gastrocnemius as well as on the level of 11-oxycorticosteroids in blood plasma of rats. The glycogen level in muscles was found to rise 3 hours after ACTH and hydrocortisone administration and it correlated with the hydrocortisone level increase in blood plasma (r = 0.714 and 0.863, respectively); the activity of pyruvate kinase decreased. Simultaneously ACTH did not change while hydrocortisone lowered the phosphorylase activity and the content of both fructose-6-phosphate and lactate.

[Effect of corticotropin and hydrocortisone on the Ca2+-ATPase activity of skeletal muscle sarcoplasmic reticulum]. / Vliianie krotikotropina i gidrokortizona na aktivnost' Ca2+-ATFazy sarkoplazmaticheskogo retikukuma skeletnykh mysh.

The effect of corticotropin (ACTH1-39), synacthen (ACTH1-24) and hydrocortisone-hemisuccinate on the activity of Ca-ATPase of skeletal muscle sarcoplasmic reticulum (SR) and calcium (Ca) accumulation in SR vesicles has been studied. It has been shown that ACTH1-39 (I U per 100 g body weight) increased the activity of Ca-ATPase in skeletal muscle SR of rats, while hydrocortisone (5 mg per 100 g body weight) did not change the activity of Ca-ATPase in skeletal muscle SR. However, both hormones increase the total activity of ATPase. ACTH1-39 and ACTH1-24 (0.05-0.0005 U/ml) and hydrocortisone (2.8 X 10(-7)-2.8 X 10(-9) mol/l) increased in vitro Ca-ATPase isolated from rabbit skeletal muscle SR and accumulation of Ca is SR vesicles. At the same time, hydrocortisone reduced calcium/phosphorus ratio, while ACTH1-39 and ACTH1-24 increased it, i.e. hydrocortisone facilitated Ca accumulation in SR requiring more ATP energy, whereas ACTH facilitated Ca accumulation in SR requiring less ATP energy.