[Induction of T-suppressors of delayed-type hypersensitivity with a background of T-effector formation]. / Induktsiia T-supressorov giperchuvstvitel'nosti zamedlennogo tipa na fone formirovaniia T-éffektorov.

Administration to mice of 10(5) syngeneic splenocytes modified with trinitrobenzene sulfonic acid leads to the formation of a population of T suppressors which are capable to sorb on a specific antigen. In recipients, these cells suppress only one phase of the induction of delayed type hypersensitivity (DTH). Their precursors are sensitive to the action of low doses of cyclophosphamide. The formation of the suppressors in question occurs during the generation of T effectors of DTH. It is suggested that the suppressors described may be attributed to Tc3 which are activated in the lymph nodes as a result of subcutaneous sensitization with antigen, and which are similar to Tc1 but have the Ly 2+ phenotype.

[Isolation and some properties of N-acetyl-beta-D-hexosaminidase from Sarcoscipha coccinea]. / Vydelenie i nekotorye svoistva N-atsetil-beta-D-geksozaminidazy iz Sarcoscipha coccinea.

N-Acetyl-beta-D-hexosaminidase was isolated from the extract of the discomycet Sarcoscipha coccinea and purified 510--550-fold by gel filtration on Sephadex G-200 and by ion-exchange chromatography on KM-Sephadex C-50 and DEAE-Sephadex A-50 or by a combination of hydrophobic and affinity chromatographies. Gel electrophoresis confirmed the homogeneity of the enzyme in both cases. Some properties of purified N-acetyl-beta-D-hexosaminidase (e. g. pH optimum, thermal stability, molecular weight, etc.) were studied. The Michaelis constants and maximal cleavage rates for some substrates were determined. The tissue extract of S. coccinea was found to contain two molecular forms of N-acetyl-beta-D-hexosaminidase. At concentrations of N-acetyl-p-nitrophenyl-beta-D-glucosaminide and D-galactosaminide higher than 0,5 mM the enzyme is inhibited by an excess of the substrate.

[Isolation and properties of N-acetyl-beta-D-hexosaminidase from the fungus Hohenbuechelia serotina]. / Vydelenie i svoistva N-atsetil-beta-D-geksozaminidazy iz griba Hohenbuechelia serotina.

N-Acetyl-beta-D-hexosaminidase (EC 3.2.1.52) isolated from the fruit bodies of Hohenbuechelia serotina (Fr.) splits N-acyl-p-nitrophenyl-beta-D-glucosaminides acylated at the amino group of the aminosugar by fatty acids, substituted benzoic acids and some amino acids and peptides. The enzyme was purified about 210-fold by chromatography on CM-Sephadex C-50 and DEAE--Sephadex A-50 and by gel filtration of Sephadex G-200 with a yield of 4%. The enzyme had pI 6,6. Some properties of the enzyme, pH-optimum, thermal stability and substrate specificity were studied. The Michaelis constants for some p-nitrophenyl-beta-D-glucosaminides were were calculated. p-Nitrophenyl N-acetyl-beta-D-glucosaminides were calculated. p-Nitrophenyl N-acetyl-beta-D-glucosaminide and D-galactosaminide at concentrations more than 0,3 mM inhibited the enzyme.

[Effect of acid polysaccharides on the corticosteroid biosynthesis]. / Vliiani kislykh polisakharidov na biosintez kortikosteroidov.

Repeated administration of carboxymethylchitin and chondroitinsulfate to rats in doses of 20 and 120 mg/kg/24 hours led to reduction (by 40-55%) of the rate of aldosterone and 18-oxycorticosterone biosynthesis by the rat adrenal glands in vitro. Carboxymethylcellulose, algin and hyaluronic acid displayed no inhibitory effect. In case of a single administration of carboxymethylchitin to rats (50 mg/kg) inhibition of the rate of aldosterone and 18-oxycorticosterone biosynthesis was seen 48 hours after the administration of the preparation and lasted four days. No inhibitory effect was induced by the addition of 10 mg/kg of acid polysaccharides into the incubation medium of the adrenal glands.

[Change in aldosterone secretion by the adrenals and in its urinary excretion in rats under the action of acid polysaccharides]. / Izmenenie sekretsii al'dosterona nadpochechnikami i ékskretsii ego s mochoi u krys pri vozdeistvii kislykh polisakharidov

Repeated administration of chondroitin sulfate to rats in doses of 20 and 120 mg/kg/24 hours led to reduction in the level of urinary aldosterone excretion in rats. Carboxymethylcellulose and alginic acid displayed no inhibitory effect. Urinary aldosterone excretion decreased in rats 24 hours after a single administration of chondroitin sulfate; this effect persisted for the following 3-4 days. The maximal reduction of aldosterone excretion (by 50%) occurred on the 3rd and the 4th day after administration of the preparation. Intraperitoneal injection of chondroitin sulfate to rats diminished the rate of aldosterone secretion by the adrenal glands; as to corticosterone secretion--it remained unchanged.