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Biomedical subjects

L V Uryvaev

Publications and source records attributed to L V Uryvaev.

At least 37 records · Page 2Linked to original sources
PubMedDate not supplied

[The isolation and identification of the Sindbis virus from migratory birds in Estonia].

The data on isolation from birds and identification of two strains of alphaviruses in Estonia in the territory of Vilsandy natural reserve are presented. Electron microscopy of purified virions allowed the isolates to be classified into the family of togaviruses, and serological identification (neutralization test, CFT) using polyvalent sera and monoclonal antibody showed them to belong to Sindbis virus.

Animals↗
PubMedDate not supplied

[The enhancement of the diagnostic reliability of immunoblot for HIV-1 antibodies by enriching the preparation for immunoblot with the HIV-1 gp120 protein].

The diagnostic value of original immunoblot system depends on the availability of enveloped protein GP120 because it is the antibodies to this polypeptide that frequently indicate the running virus infection. This polypeptide is lost during purification of viral material but remains free in culture medium. The extraction of GP120 from culture fluid with immunosorbent based on sepharose 4B with ligated immunoglobulins from HIV-1-infected persons enriched the preparation for immunoblot with proteins increasing its diagnostic value.

Carrier State↗
PubMedDate not supplied

[The detection and quantitative determination of antigens to the human immunodeficiency virus types 1 and 2].

Three modifications of ELISA test system for HIV antigen detection are described. They are based on IgG from HIV-1 and HIV-2-infected human sera and monoclonal antibodies against HIV-1 p24 used as immunosorbents. The peroxidase/anti-HIV-IgG conjugate was used in all the test systems. A possibility of quantitative detection of viral antigen in native culture fluids, lysates, and purified virus preparations was demonstrated. The test system for HIV-1 antigen detection cannot be used for HIV-2 antigen detection and vice versa. The diagnostic value of HIV-1 p24 antigen detection consists in the possibility of earlier AIDS identification and monitoring of the disease at various stages. The sensitivity of "p24" assay is 0.5 ng/ml.

Cell Line↗
PubMedDate not supplied

[Gene expression of the interferon and cell-immunity systems in human blood samples].

The interferon (IF) and cell-apoptosis (CA) systems are interrelated and regulate the protective reactions in body by means of a complex of biologically active proteins. The transcription levels of mRNA were determined by the RT-PCR semi-quantitative method in order to compare the constitutive expression levels of IF (alpha, beta, gamma) genes, IF-dependent enzymes of 2'5'-oligoadenylatesynthetyase (OAS), RNAase L, dsRNA-protein kinase (dsPK) and CA effectors (Fas-Ag, bcl-2 and gamma-actin) in human blood microsamples. cDNA dilutions, different numbers of amplification cycles (PCR with specific pairs of primers) as well as PCR-products' dilutions for dot-hybridization with specific probes were made use of to detect and evaluate levels of 9 mRNAs. The constitutive levels of gene expression of the IF and CA systems were found to differ essentially from others (1000-fold). The studied mRNA types were shared between 5 groups according to their transcription levels: very high--alpha-IF, high--RNAase L, medium--gamma-actin and bcl-2, low--beta-IF and very low (detectable after induction only)--gamma-IF, OAS, dsPK and Fas-Ag. The used detection method has a sufficiently high sensitivity and can be recommended for studies of IF inductors with unknown action mechanisms.

2',5'-Oligoadenylate Synthetase↗
PubMedDate not supplied

[Individual changes of gene expression in the interferon system in human blood cells due to amixin and cycloferon].

The action of amixin and cycloferon on the expression of genes in the systems of interferon (IF) and cell apoptosis (CA) was studied by semi-quantitative RT-PCR in human blood microsamples before and after the administration of the drugs. Individual changes were determined in the transcription activity of genes of IF (alpha, beta, gamma), enzymes 2',5' oligoadenylatesynthetase (OAS), RNSase L, dsRNA-dependent proteinkinase (dsPK) and of CA effectors (FasAg, bcl-2, gamma-actin) registered dynamically in 24 h and 48 h. The activity parameters of IF genes were compared with the results of biological titration of IF activity in blood samples in vivo and in vitro. A pronounced ability of cycloferon to stimulate selectively the activity of genes of human IF, type I (beta IF--by 100 times and alpha IF--by 10 times), without affecting essentially the activity of other genes in blood cells, was detected. Amixin was found to inhibit the titration of genes with high activity levels. (alpha-, beta-IF, RNAases L, bcl-2 and gamma-actin). The antiviral and IF-induced properties of the drug are explained to a great extent by the apoptotic effect (activation of genes Fas, gamma-IF, OAS and affected transcription of gene bcl-2). A positive correlation was observed between the processes of activation of IF-genes transcription and the production of the total circulating IF. Antagonistic relations between type I and II IFs in human blood cells were shown.

Acridines↗
PubMedDate not supplied

[Monoclonal antibodies to the Karelian fever virus. The characteristics of their biological properties].

Biological properties of 6 variants of monoclonal antibodies (MAb) to Karelian fever virus, a member of the alpha-virus serocomplex Sindbis-WEE, produced by the available hybridomas. The productivity of hybridomas of the "Karel" series in tissue culture and in cultivation as ascitic fluid was evaluated. Among the antibodies analysed, all were specific to envelope proteins, of them 2 were against protein E2 and four against protein E1. Comparison of MCA biologic activity (neutralizing, antihemagglutinating activities, participation in immunofluorescence, EIA, and immune blotting) allows one to distinguish four different hybridomas among them producing specific antibodies differing in their properties.

Alphavirus↗
PubMedDate not supplied

[Demonstration of the influenza virus A RNA by nucleic acid molecular hybridization using biotin-treated probes].

A probe containing full-size DNA copy of influenza A/USSR/90/70 virus protein gene M labeled with biotin on 32P was used for influenza A virus RNA detection by dot hybridization method. For labeling with biotin, a new method of its administration by chemical modification of nucleic acid was employed. In homologous DNA:DNA hybridization the sensitivity of determinations was less than 1 pg in the biotin-treatment of the probe and 1.25 pg in its radioactive labeling. Hybridization of DNA probe with cytoplasmic RNA isolated from influenza A virus-infected (strains A/USSR/90/77 and A/Texas/77) MDCK cells revealed RNA in the dot corresponding to 4.5-5.5 1g ID50 of virus present in 2 x 10(4) cells. The probe did not bind with negative controls in any dot in all the tests. The results of the study indicate that DNA probes labeled with biotin and 32P and used in dot hybridization for influenza A virus RNA detection in infected cells show the similar sensitivity and specificity.

Biotin↗
PubMedDate not supplied

[A comparative analysis of the polypeptides of the the Sindbis and Karelian fever viruses].

In pulse-chase experiments with Karelian fever virus-infected cells, proteins were found with molecular weights of 130, 98, 78, and 62 kD of which the first, second and fourth were classified as polypeptide precursors of the structural proteins of virion. The molecular weights of proteins E1, E2 and C of 52, 47 and 34 kD, respectively, as well as isoelectric points of isolated glycoproteins (pI E1 = 6.3, pI E2 = 8.4) were similar in KFV (strain Leiv-9298) and Sindbis virus (strain AR339). The antigenic similarity of the strains under study in neutralization test with hyperimmune sera, the identity of physicochemical characteristics of the structural proteins of KFV and prototype Sindbis virus strain suggest a close relationship of the Leiv-9298 strain to the Afro-European variants of Sindbis virus.

Alphavirus↗