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Biomedical subjects

D Nashkov

Publications and source records attributed to D Nashkov.

8 recordsLinked to original sources
PubMed1978

[Effect of physical and chemical factors on the antigenic activity of the cell walls of Brucella abortus 99].

Studied was the effect of some physical and chemical factors--heating, acidity, treatment with ultraviolet rays, and enzyme treatment--on the activity of the Brucella abortus 99 cell wall antigen. The activity of the antigen was determined through the microreaction of complement-fixing after Kolmer. It was found that the antigen was most sensitive to acid treatment and treatment with ultraviolet rays, and was more slightly sensitive to the effect of alkaline agents and pronase. Besides, the antigen proved heat-resistant and did not lose its activity after treatment with trypsin and alph- and beta-amylase. The chemical nature of the epitopes (the determinant groups), substantiating the activity of the antigen is briefly discussed.

Amylases↗
PubMed1978

[Soluble regulators produced by the lymphocytes].

Data are given on lymphokins, the biologically active substances lymphocytes when the latter are stimulated with specific antigens or unspecific mitogens. Discussed are their essence, antigen specificity, cell origin, and the methods of purification, standardization, and evaluation of biologic importance. It is believed that the lymphokins appear to be the products of primary activation of T lymphocytes. They possess pharmacologic activity, but have no antigenic specificity. Their function consists in mediating hypersensitive and inflammatory reactions through the activation of phagocytes. The effectiveness of cellular immunity depends on the activity of these factors.

Animals↗
PubMed1976

[Chemical and immunologic study of the bacterial wall of Brucella abortus 99].

The investigations were carried out through the CFT serologic activity of some of the Brucella abortus 99 cell components. It was found that only 0.6 per cent of the weight of the bacterial walls could be extracted by means of physiologic saline. The extracts proved to be serologically active and specific for these Brucella organisms only. The wall of Brucella abortus 99 and its peptidoglucan were shown to be rich in lysine, leucine, glitamic acid, and valine, and poor in methionine, histidine, treonine, and, generally, in sulfur-containing amino acids. The presence of higher content of lysine and glutamic acid explained the higher resistance of the bacterial walls of Brucella abortus 99 as compared to that of M. Lysodiecticus. The wall of Br. abortus 99 contains high amounts of phosphatidil acids - 16.4 per cent of the total amount of lipids. The biologic importance of the results obtained is briefly discussed.

Amino Acids↗
PubMed1975

[Determination of biologically active protein fractions and their polypeptide chains in pseudoplague virus (NDV)].

The protein fractions of the intact Newcastle disease virus as well as those of a disintegrated NDV (treatment with tween 80, ether and triton times 100) were separated through electrophoresis on polyacrylamid gel. Determined were the biologic activity, molecular weight and number of polypeptid chains of each fraction. It was found that 5 of the fractions obtained are composed of aggregates of 3 polypeptid chains, and 2 of the fractions represent single polypeptide chains. The haemagglutination and neuraminidase activity of the virus were found to be linked with the aggregates having molecular weight within the range of from 144,000 to 180,000 daltons. The complement-fixing activity observed is possessed by the single polypeptid having molecular weight of 62,000 daltons. It was demonstrated that the NDV strain that is not pathogenic for birds possesses a polypeptide with a molecular weight of 70,000 daltons, at is is not involved in the building of the protein aggregates.

Antigens, Viral↗