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Biomedical subjects

L Vasileva

Publications and source records attributed to L Vasileva.

32 records · Page 2Linked to original sources
PubMed1979

[Conformational changes in the membranes of cells infected with Newcastle disease virus].

Studied were the conformational changes in the membranes of BHK cells infected with two ND virus strains varying in their virulence, by means of determining the binding sites in the membranes with the fluorchrome ANS. These changes set in immediately after the adsorption of the strongly virulent strain Petleshkov as well as from the second to fourth hour following the infection of the cells with the less virulent strain Rousseff. It is believed that such changes in the membranes of infected cells are due to the invasion of the virus into them, which is accompanied by fusion.

Adsorption↗
PubMed1978

[Production of purified foot-and-mouth disease virus antigens and the specific sera against them].

It was demonstrated that the use of laboratory techniques could be contributive to the production of purified antigens of the F.M.D. virus, such a-140 S, 12 S, and VIA. The isolated purified antigens were used to immunize guinea pigs, obtaining specific antisera against them. It was found that the latter contained specific complement-fixing and precipitating antibodies, while the 140 S serum also had neutralizing antibodies. The produced 140 S serum contained certain amounts of 12 S antibodies, which was considered to be the result of a spontaneous degradation of the 140 S antigen.

Animals↗
PubMed1977

[Sensitivity testing of chick embryo subcultures to the Newcastle disease virus].

A total of five passages of subcultures were produced from chick embryos with the use of a medium enriched with a 10 per cent solution the previous passages of the cells. The form, number, and size of the plaques obtained at the cultivation of the Newcastle disease virus in the cells of the various passages of the subcultures did not differ. The virus production per cell did not also change substantially with the increase in the number of subculture passages.

Animals↗
PubMed1976

[Changes in enzymatic activity in rats with acute Unden poisoning].

The influence of Uden, exerted on the activity of GOT, GPT, LDH acid phosphatase and alkaline phosphatase in the serum, is investigated upon 4-day-long treatment. The experiment is conducted in three groups of white male rats with mean weight 270 +/- 20 g. The first group of animals underwnt poisoning with 1/20 LD50, the second--with 1/4 LD50 while in the third, control group, the animals were treated with an oil solvent at the respective days. It is found that acid phosphatase, GOT and alkaline phosphatase activity in group two is virtually unchanged, whilst GPT activity in both experimental groups, and acid phosphatase in group one are reliably increased (P less than 0,01), with 20,17 and 53 per cent respectively. LDH activity is reliably lowered with 60 per cent in group two, whereas in group one a tendency for a reduction is noted (P less than 0,05).

Acute Disease↗
PubMed1976

[Effects of concanavalin A on the adsorption and penetration of paramyxoviruses into cells].

The lectin concavaline A, when added to cell cultures of chick embryos and calf kidney one hour prior to their injection with the virus of the Newcastle disease and that of parainfluenza-3 in cattle produces no adverse effect on the cell receptors of these viruses. On cells treated with concavaline 60 per cent and more virions are adsorbed as compared with the untreated cells. This is explained by the fact that concavaline binds to the cellular and viral glucoproteins. Virions bound to concavaline do not penetrate into the cells. The titers of the paramyxoviruses obtained from lectin-treated cells were by 2 log. lower than the virus titers obtained from untreated cells. Mono- and bivalent concavalines inhibit more slightly the reproduction of para myxoviruses.

Adsorption↗
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↗