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Biomedical subjects

L Khristoforov

Publications and source records attributed to L Khristoforov.

8 recordsLinked to original sources
PubMed1979

[Differentiation of nonspecific serological reactions in brucellosis].

Differentiation of non-specific agglutination was performed by the complement binding reaction, Coombs' reaction, Hajdu reaction, the surface fixation and agglutination reaction and the reaction of complement binding with heterologic antigens. For that purpose the following were used: 1) Serums--antiglobulin against cattle globulin, 5720 serum of various animals which had manifested non-specific agglutination with brucella antigen and brucella serums of experimentally infected sheep, of naturally infected swine and of cattle--received from abroad. 2) Antigens--of Br. abortus 99, of bacteria heterologic to brucellae: Proteus vulgaris, Listeria monocytogenes, Staphylococcus albus, Escherichia coli, Streptococcus pyogenes, S. abortus ovis, for O and OH agglutination, water extraction antigens--for complement binding and concentrated suspensions of all bacteria used in brucellose and non-brucellose serum absorption. Highest number of non-specific reactions were observed in cattle serums and lowest--in goat serums. Titers with heterologic antigens were higher than these with brucella antigens. Often the serum having non-specific agglutiantion reacted not only with one, but with more heterologic antigens. Non-specific complement binding reactions were not produced in complete antibodies with the brucella antigen. Heterologic brucella antigens were exhausted more fully than heterologic complement binding antibodies. In their effectiveness (differentiation of non-specific agglutination with brucella antigen in cattle serum) the serological reactions studied rank as follows: complement binding reaction, slow agglutination with serums absorbed by heterologic antigens, surface fixation reaction, Coombs' reaction, and Hadju agglutination.

Animals↗
PubMed1979

[Comparative studies between different methods for demonstrating blocking antibodies in experimental Br. melitensis infection in sheep and goats].

In the course of 4 years 4624 serums of 34 sheep and 4 goats experimentally infected with Br. melitensis biotype 1 and biotype 3 in a chronic phase of the Brucella infection process and 2792 serums obtained from part of the same sheep in acute and subacute phase of Brusella infection were investigated. In was established that Coomb's test and the cysteine test show greater constancy in proving the existence of blocking antibodies. They are followed by the Brucella blocking test after Renoux and the mercaptoethanol test. In the complement binding reaction participate mainly mercaptoethanol-sensitive antibodies, while in the presence of blocking (mercaptoethanol resistant) antibodies the complement binding reaction is characterized by binding a smaller amount of the complement. Cold complement binding leads to increased titers of complement binding antibodies mainly in respect to blocking antibodies. Positive hemocultures are established more often in case of mercaptoethanol-sensitive agglutinins in high titers, while positive urocultures--in case of high titer reaction of complement binding, in case of higher titers of blocking antibodies or in case of positive complement binding reaction and higher content of blocking (mercaptoethanol resistant) antibodies.

Animals↗
PubMed1979

[Diagnostic titers in neorickettsiosis in sheep, cattle and swine].

Investigations were carried out after a micromethod for RCB formulation and standardization proposed by the authors used as the basic method of neorickettsiosis diagnositcs. In the course of 4 years 3614 serums of healthy animals and 289 serums of sheep, cattle and swine suffering from neorickettsiosis were investigated. It was established that the titre of complement binding antibodies in neorickettsiosis is stable. Variations are rarely observed and they are of low titre grade. Specific neorickettsiosis titres in sheep, cattle and swine are considerably high (1:128 to 1:256 and 1:512). The diagnostic value of low titres is in correlation with the phase of the infection process development and can be assessed only by following the dynamics of complement binding antibodies.

Animals↗
PubMed1978

[Diagnostic value of agglutination reaction with buffered Brucella antigen stained with rose bengal].

A specific buffered antigen has been obtained, employing a method developed by the authors, stained with Bengal rose and intended for performing a fast agglutination reaction to confirm brucellosis. The antigen produces a clear and demonstrative agglutination reaction with positive sera. Practically, the test is readily carried out, and can be made a routine both in every serologic laboratory and for investigations under field conditions. The reaction produced with this antigen can determine dependably the epizootic status on a farm or in the herd. The diagnostic value of the antigen is essential, especially with swine. Besides, it shows a wide a diagnostic scope for brucellosis with all species of animals (97--98 per cent).

Agglutination Tests↗
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↗
PubMed1977

[Differentiation of non-specific positive brucellosis reactions using an antigen stained with rose bengal].

A Brucella buffered antigen, stained with Bengal rose by a method of the authors, was obtained. It showed a high distinguishing capacity with regard to the nonspecific agglutinations after Huddleson and Wright at a negative complement-fixation test for brucellosis with sera from cattle, pigs, sheep, and horses. Such differentiation, however, proved to be incomplete and for sera of different animals varied within the range of 34 to 0.0 per cent.

Agglutination Tests↗
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↗