PubMed Health⌕ Search

Biomedical subjects

V M Zhdanov

Publications and source records attributed to V M Zhdanov.

At least 19 recordsLinked to original sources
PubMed1992

[Studies of AIDS in Lithuania].

The seroepidemiological survey of 400,000 persons aged 20-40 years and belonging to different AIDS risk groups, as well as blood donors, for the presence of antibodies to HIV has been carried out on the territory of Lithuania. This investigation has been made with the use of the assay systems "Antigen", "Peptoscreen" and "Vector" manufactured in the USSR, as well as commercial assay systems from foreign manufacturers, such as Du Pont de Nemours Inc., Organon N. V., Abbott Laboratories, Serodia. The comparison of the results thus obtained has revealed that high frequency of false positive results is characteristic of all assay systems under study, including immunoblotting. These data indicate that test systems based on different acting principles should be used for the detection of anti-HIV antibodies. For the first time a HIV-infected resident of Lithuania has been detected. The investigation carried out in Lithuania has shown that HIV infection is not widely spread in this region, but due to some objective reasons this does not preclude the necessity of the constant epidemiological surveillance of this infection throughout this territory in order to bar the way to this infection.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Molecular and biological properties of a variant of avian influenza A/Seal/Massachusetts/1/80 (H7N7) virus that is pathogenic for mice.

A/Seal/Mass/80 influenza virus has been shown to be closely related antigenically and genetically to avian influenza H7N7 viruses, however, the virus does not replicate efficiently in avian species but does replicate in most mammals, except mice (Hinshaw et al., Infect. Immun., 34, 351-361, 1981). In order to develop a model defining the molecular changes that occur during acquisition of virulence, the A/Seal/Mass/80 virus was adapted to growth in mouse lungs. The adaptation was accompanied by changes in a number of properties of the haemagglutinin as well as by changes in other genes of the virus as determined by RNA: RNA hybridization.

Animals↗
PubMed1988

Controlled organization of multimolecular complexes of enveloped virus glycoproteins: study of immunogenicity.

Some technological and immunological problems facing the preparation of subunit viral vaccines are discussed. Solubilization of enveloped virus glycoproteins with various detergents has been studied. It has been demonstrated that a novel non-ionic detergent, MESK, can be used to prepare the glycoproteins of enveloped viruses in defined supramolecular forms: monomers, micelles, liposomes and multimeric complexes. These preparations have been tested for immunogenicity. It has been shown that the immunogenicity of glycoproteins in micellar form or in liposomes is comparable with that of the whole virus. The immunogenicity of the glycoprotein complex with the glycoside Quil A appeared to be significantly higher in comparison with the whole virus and was similar to the immunogenicity of glycoproteins mixed with Freund's complete adjuvant.

Animals↗
PubMed1988

[Comparative analysis of the DNA of Corynebacterium diphtheriae phages and the cloning of the gene determining diphtheria toxin synthesis].

The analysis of the DNA of one nontoxigenic C. diphtheriae phage and two toxigenic ones has revealed that phage phi 984tox+ belongs to omega-like tox+ phages, phage phi 9tox+ is a representative of a new group of phages and phage B (Freeman) tox is a deletion mutant of phage beta. The location of this deletion on the physical map of this phage has been established. To obtain the physical map of phage phi 984tox+, the complete library of internal DNA fragments has been constructed in vector pBR 322. The gene of native diphtheria toxin has been cloned in vectors pBR 322 and pUR 250. Plasmids pUR 250 with the inserts of the toxin gene have been shown to be unstable if tox and lac promoters are located in tandem before the body of the toxin gene. The prolonged cultivation of clones having such structure leads to the formation of a spontaneous mutation located in the region coding the C-end part of the A-fragment of the toxin.

Bacteriophages↗
PubMed1988

[Expression of gag gene of human immunodeficiency virus in recombinant vaccinia virus].

A fragment of HTLV-IIIB gag-gene, coding for the first 441 amino acids of the p53 gag-precursor was expressed in the recombinant vaccinia virus, vC5. Two HIV specific proteins were detected by western blot in CV-1 cells infected with vC5. Their relative molecular masses were 50 and 35 Kd, pointing out that the first of the proteins is a full length expression product of the cloned sequence, while the second one is a result of processing or abortive translation. Possibilities of using such a strain as a vaccine or in Western blot conformation test are discussed.

Gene Expression Regulation↗
PubMed1987

Effect of beta-decay of radionuclides incorporated into influenza virus RNA and proteins on the infectivity of the virus and antigenicity of its nucleoprotein.

The effect of beta-decay of radionuclides incorporated into influenza virus on the properties of the two closely adjacent structures--RNA and nucleoprotein (NP)--was studied. The long-term storage of 3H-uridine labelled influenza virus was shown to lead to the loss of infectivity. This effect may be explained by lethal intra-molecular modifications of viral RNA, caused by beta-decay of 3H incorporated into the molecule. There was an accompanying decrease of monoclonal antibody (MAB) binding activity, this also being a plausible result of beta-decay. The different rates of inactivation of MAB binding activity of different epitopes of NP of the 3H-labelled virus shown in our studies suggest that there are different types of structural organization or different location of these epitopes in the NP. The effect of 3H-decay on the intracellular RNA of reproducing virus lead to a decrease in virus yield; this may be due to radiation- and transmutation-induced damage of messenger and progeny RNA populations synthesized during the infection. The storage of influenza virus labelled with 14C-aminoacids lead to a decrease in MAB binding activity of the NP that was unaccompanied by a decrease in infectivity. Furthermore, 14C-decay in proteins of reproducing virus had no adverse effect.

Animals↗
PubMed1987

Prediction of secondary structure, spatial organization and distribution of antigenic determinants for hepatitis A virus proteins.

On the basis of the secondary structure calculations from the known amino acid sequence we came to the conclusion that hepatitis A virus capsid proteins have the typical antiparallel beta-sheet bilayer structure. The predicted secondary structure of the HAV proteins can be well aligned with those of the poliovirus (type 1 Mahoney) and human rhinovirus (type 14). It enabled us to use the X-ray structure of the PV-1M and HRV-14 proteins as a template and then, firstly, to localize the positions of alpha and beta regions in the architecture of the HAV protein molecules and, secondly, to discover the amino acid homologies of the secondary structure regions aligned. The obtained model of the three-dimensional structure for HAV proteins helped us to indicate the exposed regions of the polypeptide chains and to pinpoint the potential neutralizing antigenic sites.

Amino Acid Sequence↗
PubMed1987

[Detection of genomic RNA of the hepatitis A virus in clinical samples using the blot hybridization method].

The synthetic oligonucleotide sequence 3'CTCCTCGTACTTTA-5' complementing hepatitis A virus RNA was compared with cDNA probes in identification of viral genomic RNA. The clinical materials from patients in the 1-2 weeks of jaundice were screened. High specificity of the technique was demonstrated. Possibility of clinical using of the blot hybridization technique is discussed.

DNA↗
PubMed1987

Studies on influenza-virus virulence in recombinants between epidemic and vaccine strains.

Influenza virus recombinants between epidemic strains A/Brazil/11/78 (H1N1), A/USSR/382/78 (H3N2) and vaccine strains A/Leningrad/9/46 (H1N1), A/Victoria/35/72/50 (H3N2) have been tested for virulence for humans and albino mice; their genome structure has also been determined. It has been shown that after the replacement of surface antigens of A/Leningrad/9/46 (H1N1) strain by surface antigens of A/Brazil/11/78 (H1N1) or A/USSR/382/78 (H3N2), strains, the virus becomes totally nonpathogenic for mice whereas its virulence for humans is enhanced. The combination in recombinant X/28 (H1N1) of haemagglutinin and neuraminidase of A/Brazil/11/78 (H1N1) virus and othercomponents of A/Leningrad/9/46 virus determines its high affinity to the epithelium of the upper respiratory tract of humans, as well as its marked virulence for seronegative volunteers. Genetic mechanisms of influenza virus virulence and the involvement of surface proteins in its specific manifestations are discussed. It has been shown that pathogenic properties and the affinity of the virus to particular tissues are determined by different genes and their reasortment can result in the appearance of essentially new properties in recombinants.

Animals↗
PubMed1986

Studies on the genetic determinants of influenza virus pathogenicity for mice with the use of reassortants between mouse-adapted and non-adapted variants of the same virus strain.

The original influenza virus strain A/USSR/90/77 (H 1 N 1) and its mouse-adapted variant, differing in their reactivity with anti-hemagglutinin monoclonal antibodies HC 22 and HC 124, were crossed in MDCK cells and in chicken embryos, and 21 clones were isolated by non-selective random cloning. In all the clones the virulence for mice was found to be linked to the antigenic specificity of hemagglutinin (HA). An independent marker, formation of filamentous forms, was reassorted with an expected frequency. In the crosses between UV-irradiated mouse-adapted variant and live non-adapted strain, with selection of clones by a mixture of monoclonal antibodies discriminating between HA of the two variants, virulence also was linked to HA gene. On the contrary, in the experiments with A/Aichi/2/68 (H 3 N 2) strain and its mouse-adapted highly virulent variant these two characteristics--virulence and HA antigenic specificity--could be dissociated. A pathogenic clone having HA of the non-adapted strain was readily obtained; its virulence, however, was weaker than that of the mouse-adapted parent. In the inter-subtypic crosses between A/USSR/90/77 and A/Aichi/2/68 the transfer of the HA gene of the mouse-adapted A/Aichi/2/68 did not confer virulence to the reassortant. The results are discussed in terms of the genetic basis of virulence acquired in the course of influenza virus adaptation to a new host.

Animals↗
PubMed1986

Detection of viral antigens by solid phase radioimmunoassay on polyethylene film.

Polyethylene film, without any pretreatment, may serve as a solid phase (SP) for RIA. Viral antigens (HBsAg, and influenza virus) are detected by SP-RIA on the film with a sensitivity of about 2-3 ng/ml or 40-60 pg/assay. The use of polyethylene film allows one to record RIA autographically. The use of micro amounts of reagents and specimens tested is an added advantage. No special equipment is necessary, the method is inexpensive, easy to perform and may be used for mass screening.

Animals↗
PubMed1986

Dissociation of the haemagglutination inhibition and the infectivity neutralization in the reactions of influenza A/USSR/90/77 (H1N1) virus variants with monoclonal antibodies.

Variants of influenza A/USSR/90/77 (H1N1) virus selected with monoclonal antibody HC 142 (Res 142-1 and Res 142-2) were resistant to this antibody in a virus-neutralization (VN) test, but were inhibited in a haemagglutination-inhibition (HI) test. A variant selected with HC 22 monoclonal antibody (Res 22) was resistant to HC 142 only in VN tests. A mouse-adapted variant of A/USSR/90/77, shown previously to be resistant to HC 22, reacted with HC 142 in a manner similar to that of Res 142-1, Res 142-2 and Res 22. Another monoclonal antibody, HC 125, behaved similarly to HC 142. The addition of anti-immunoglobulin serum restored the ability of HC 142 and HC 125 (already bound to the virus) to neutralize the infectivity of the resistant variants. Polyacrylamide gel electrophoresis revealed differences in the mobility of haemagglutinin among the variants.

Antibodies, Monoclonal↗
PubMed1986

[Properties of monoclonal antibodies interacting with determinants of hepatitis B virus surface antigen].

Fourteen hybridoma clones have been isolated producing the monoclonal antibodies to the surface antigen of the hepatitis B virus (HBsAg). Monoclonal antibodies have been shown to react in high titres with HBsAg in the reactions of PHA, PH and ELISA. The specificity of monoclonal antibodies to two antigenic determinants has been found by the competitive solid phase ELISA technique. Monoclonal antibodies from nine clones react with one determinant while monoclonal antibodies from the rest five clones react with the other nonoverlapping determinant.

Animals↗