A decrease in the content of immunoreactive alpha- and gamma-endorphins in the blood and the suppression of their hypersecretion under the influence of dexamethasone in emotional stress in monkeys

Daily administration of 12 mg of dexamethasone to monkeys during 10 days resulted in decrease of the levels of alpha- and gamma-endorphins and cortisol 7 days after the first injection. The titers of these peptides in plasma of monkeys. exposed to two hours of immobilization stress were elevated twice above basal levels. The maximum elevation took place 6 hours after the beginning of immobilization. This effect wasn't detected in monkeys, which received 12 mg of dexamethasone during 10 days.     

Lipid peroxidation in experimental Salmonella infection

The results of investigation of lipid peroxidation in experimental Salmonella infection in 21-day-old rabbits are analyzed. Salmonella infection was accompanied by activation of lipid peroxidation not only in enterocytes, but also in blood serum. An increase in the level of malonic dialdehyde leads to a decrease in the antioxidation capacity and in the peroxidation resistance of erythrocytic membranes. The severity of the pathological process was found related to the activity of lipid peroxidation.     

Kinetics of reversible inhibition of cholinesterases by quaternary diaminoalkyl esters of aromatic dicarboxylic acids]

Reversible inhibition of acetylcholinesterase (AChE) from bovine erythrocytes and butyrylcholinesterase (BuChE) from horse blood serum by quaternary diaminoalkyl esters of suberic (D-6), p-phenylenediacetic (PK-139), p-phenylenedipropionic (PK-154 and PK-155), p-phenylenediacrylic (PK-150 and PK-151) and phthalic (PK-105) acids, was studied under the following incubation conditions: pH 7.5, 25 degrees C, 0.1 M KCl. The inhibition kinetics were of a mixed competitive-incompetitive type, the incompetitive component alpha'-having higher values for AChE (0.26-0.60) than for BuChE (0.10-0.20). Diester PK-150 selectively inhibited BuChE (Ki=3.0-10(-6) M); its Ki value for AChE was 4.0-10(-4) M. The other diesters had a stronger inhibitory effect on AChE than on BuChE. High values of alpha' observed during AChE inhibition cannot be interpreted in terms of interaction of those bisquaternary compounds with the anionic site of the acetylated active centre and are probably due to their sorbtion at the peripheral anionic sites. Incompetitive inhibition constants (K'i=Ki/alpha') of BuChE by the diesters PK-139, PK-154 and PK-150 were found to be values of the same order as substrate inhibition constants determined in the course of BuChE hydrolysis of these diesters. Incompetitive inhibition found for the esters studied and substrate inhibition during hydrolysis of these compounds are presumably due to the same mechanism.     

The peculiarities of repair DNA-polymerases in the loach embryogenesis

The current concept of eukaryotic DNA polymerases is considered, which are involved in nuclear DNA repair. The data are given on a new group of DNA polymerases that maintain the integrity of DNA structures without preliminary excision of damaged regions. A special attention is paid to specific features of the functioning of repair DNA polymerases in embryogenesis of the loach. A possible existence is discussed of the previously unknown pathway of DNA repair with participation of DNA polymerase delta as independent from the nuclear antigen of proliferating cells.