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V N Loparev

Publications and source records attributed to V N Loparev.

16 recordsLinked to original sources
PubMed1991

An efficient and simple method of DNA extraction from whole blood and cell lines to identify infectious agents.

Routine methods of extraction of DNA from blood involve the enrichment of cells by Ficoll-Hypaque gradient centrifugation followed by lysis of the cells with extraction buffer, proteinase K digestion of the lysate, and phenol:chloroform-isoamyl alcohol extraction. These methods generally require large amounts of blood, which poses a problem with pediatric patients. To overcome this, we developed a new method of extracting DNA directly from whole blood. This method involves the treatment of whole blood with an equal volume of NaI (3 M final concentration) followed by chloroform:isoamyl alcohol extraction to clear hemoglobin and cell debris. The clear aqueous layer is then mixed with isopropanol to obtain DNA. A large number of samples can easily be handled by this extraction procedure, as it can be carried out in 30 min and requires only a microcentrifuge.

Base Sequence↗
PubMed1991

[Synthesis of the E-antigen of the hepatitis B virus (HBeAg) in eukaryotic cells by a recombinant strain of the vaccinia virus].

The recombinant plasmids containing the gene for hepatitis B viral core-antigen with the pre-core-sequence controlled by the early-late promoter of the 7.5' K protein gene were constructed. The recombinant strains of vaccinia virus were obtained on their basis (vHBe42-1 and vHBe42-3) selectively expressing HBeAg of hepatitis B virus. The kinetics of HBeAg synthesis was studied in infected cells as well as secretion of the protein into culturing medium. Three proteins were found by blotting technique in the cells infected by vHBe42-3 that react with the specific antiserum to HBeAg and have the mol. masses 25, 22 and 17 kD. The completely processed HBeAg 17 kD was found in the culturing medium. The rabbit serums from the animals immunized by recombinant vHBe42-3 contained antibodies to HBeAg but not to HBcAg. This makes it possible to study the structural and functional organization, immunological properties and role of this antigen in pathogenesis of hepatitis virus B and to construct the specific test systems for screening HBeAg and corresponding antibodies.

Animals↗
PubMed1990

Smallpox diagnosed 400 years later: results of skin lesions examination of 16th century Italian mummy.

Results are presented on virological examination conducted on WHO request of a Naples infant mummy with smallpox-like lesions. Electron microscopy of lesions confirmed the findings of Italian researchers: well-preserved virus-like structures, whose size and morphology were identical to those of orthopoxviruses have been revealed. It was shown that the virus in mummy skin had lost its viability. Viral antigenic activity could not be detected in EIA or RPHA, nor was determined its DNA in the test of DNA molecular hybridization.

Child, Preschool↗
PubMed1989

[Vaccinia and ectromelia recombinant viruses, causing an infection, characteristic for ectromelia, in mice].

Ten recombinants between the viruses of vaccinia and ectromelia were isolated that cause the ectromelia virus specific lesions in mice. The structure of recombinant viral genomes, the efficiency of viral propagation in mice, the nature of lesions induced by viruses have been studied. Eight of obtained recombinants have a DNA insertion originating from the right end of ectromelia viral genome, nine recombinants have an insertion originating from the left end, seven recombinants possess both insertions. The latter recombinants have more pronounced pathogenicity for mice. Both revealed regions are supposed to define the specific pathogenicity of ectromelia virus for mice.

Animals↗
PubMed1988

[Mapping of "nonessential" regions in the genome of vaccinia virus].

The special molecular probe for mapping the "nonessential" regions in the genome of vaccinia virus has been obtained by the genetic engineering methods. The probe included the gene for beta-galactosidase of E. coli under the control of vaccinia virus 7.5 K protein promoter as well as the gene for kanamycin resistance. In its final version the probe is obtainable from the plasmid pUCZ beta using the restriction endonucleases SalI, BamHI, EcoRI. The probe included by the BamHI fragment of DNA was inserted into the HindIII-E-fragment of the vaccinia virus (cloned into a plasmid) in 8 of the existing 9 BglII cleavage sites. The latter plasmids were introduced into the chicken embryo cells infected by the vaccinia virus. The plasmid having the probe inserted into the 5th BglII site (from the left end) of the HindIII-E fragment permitted to obtain the live vaccinia strain expressing the beta-galactosidase. Thus, the "nonessential" region of vaccinia virus, that was not described previously, is mapped.

Cloning, Molecular↗
PubMed1987

[Expression of beta-galactosidase in recombinant nonintegrated plasmids in evaluating the functional activity of vaccinia virus promoters].

The recombinant plasmids pVL1 and pVL2 were constructed for insertion and expression of alien genetic information in HindIII-F fragment of vaccinia virus DNA under the control of the strong early-late promoter of the protein 7.5. The late promoter of the main late protein 11K of vaccinia virus was cloned. These as well as other vector plasmids have been used to express the procaryotic beta-galactosidase gene. Functional activity of the genetic engineering constructions was estimated by transitory expression of beta-galactosidase after plasmid DNA transfection into the chicken fibroblasts embryo culture infected with vaccinia virus. The promoters of the genes for 7.5K and 11K proteins permitted the high level of beta-galactosidase expression. Using of the early promoter of the central part of HindIII-F fragment DNA from vaccinia virus was less efficient for expression of the enzyme.

Galactosidases↗
PubMed1986

[Comparative restriction analysis of HindIII-F-fragments of DNA from 4 strains of vaccinia virus].

The localization of KpnI, SacI, XhoI, AvaI, PstI, BglI, BamHI, EcoRI, PmiI, SalI, BglII, restriction endonuclease cleavage sites in HindIII-F-fragments of DNA from vaccinia strains WR, Copenhagen, LIVP and neurovaccine has been detected. The fragments have been shown to differ in the number of AvaI, EcoRI and BamHI sites. The fragments also differ from the analogue of Tian Tan vaccinia strain in the pattern of restriction by AvaI, XhoI, PstI, EcoRI and BamHI endonucleases.

Base Sequence↗
PubMedDate not supplied

[Electron microscopic study of the genome homology of simian adenoviruses].

DNA homologies of simian adenoviruses SA7, SV20, SV30, SV38, and SA7(C8), clone 230, were studied. The genomes of SV20, SV30, and SV38 differ from each other insignificantly (at least 85% of homology), but from the SA7 genome significantly (50-70% of homology). DNAs of SV20, SV30, and SV38 contain four main regions of melting in 90% formamide: two terminal A-T-rich regions are located symmetrically on the termini of the molecules, and two on the right parts of the molecules. SA7 virus DNA differs from that of the three above-mentioned viruses by the A-T composition and contains only two regions of melting on the right part of the molecule under similar denaturating conditions. SV20, SV30, and SV38 DNAs contain the inverted terminal repetitions of the order of 147 nucleotides long, and SA7 DNA contains considerably longer inverted terminal repetition: 230 nucleotides.

Adenoviridae↗
PubMedDate not supplied

[Biological properties of large-plaque clone 230 of simian adenovirus SA7(C8)].

The clone KB-230 of simian adenovirus SA7(C8) is described differing from the reference SA7(C8) strain and clones KB-2 and MB-1 by the presence of additional recognition sites when treated with different endonucleases. The KB-230 clone differs antigenically in the neutralization test from the MB-1 clone. Some biological and molecular-biological properties of the KB-230 clone were studied. All the simian cell cultures under study were highly sensitive to the cytopathic effect and replication of the KB-230 clone. The reproduction cycle of the KB-230 clone was 12 h, that of KB-2 clone 16 h. The maximum accumulation of virus in the cells was observed by 27-29 h for both clones. The KB-230 clone differed from the KB-2 clone by early development of the CPE (by 9 h of cultivation against 19 h for the latter). The oncogenic activity of the KB-230 clone was less marked than that of the MB-1 clone. The methods of heteroduplex and polypeptide analysis established the difference of the KB-230 clone from the reference SA7(C8) strain and KB-2 and MB-1 clones.

Adenoviridae↗
PubMedDate not supplied

[The importance of the blood transfusion factor in the epidemic process in hepatitis C in the patients of chronic hemodialysis units studied using a computer simulation model].

Examinations for the presence of antibody to hepatitis C virus (HCV) were carried out in 144 patients of chronic hemodialysis wards and 83 blood donors. The anti-HCV were found in 26.4% of the patients and only in 1.2% of the blood donors. A definite increase in the incidence of HCV infection in the patients of hemodialysis wards was established in relation to the duration of the treatment, namely from 17.4% in the patients treated for up to 1 year to 37.5% in those treated for 6 years or more. Significant differences were observed in the rate of anti-HCV findings in the patients with kidney transplantation and in those who had not experience this operation. The results obtained by an imitation computer model indicated that the hemotransfusion factor is not the only one determining the high rate of HCV infection in patients of chronic hemodialysis wards, however its influence on the intensity of the epidemic process in hepatitis C in these wards was sufficiently high.

Adult↗