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Biomedical subjects

E A Tkachenko

Publications and source records attributed to E A Tkachenko.

90 records · Page 5Linked to original sources
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[Serologic examination of patients with hemorrhagic fever with renal syndrome in the European part of the USSR].

Certain features of humoral immunity in patients suffering from hemorrhagic fever with renal syndrome (HFRS) in the territory of the European USSR were established: a trend for increasing antibody levels for a long time after convalescence (approximately 6 months) and the lack of significant decline of antibody levels for many years (5-10). Comparative clinico-serological studies revealed the occurrence of subclinical and atypical forms of HFRS disease.

Adolescent↗
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[Indirect hemagglutination test for indicating the HFRS virus and the laboratory diagnosis of the disease].

Conditions have first been developed for the preparation of erythrocyte immunoglobulin diagnostic preparation of erythrocyte immunoglobulin diagnostic preparation for HFRS virus which permits express detection of the specific virus antigen in suspensions of the lung tissue of rodents by means of the indirect hemagglutination test (IHA) and laboratory diagnosis of the infection in humans by means of antibody detection by the indirect hemagglutination-inhibition test (IHAI). The IHA test is as sensitive as immunofluorescence, while the sensitivity of the IHAI test is not inferior to that of immunofluorescence but is higher than that of RIA.

Animals↗
PubMedDate not supplied

[Isolation of the protein component of the soluble Tamiami virus antigen by using affinity chromatography on IgG-cellulose].

IgG to Tamiami virus is covalently bound to metaaminobenzylcellulose by nitrogen coupling. An immune sorbent was prepared and used to treat the virus soluble antigen (SA); a protein responsible for the serological properties of SA was isolated. Electrophoretic analysis in polyacrylamide gel showed this protein to be a nucleocapsid protein of the virion.

Animals↗
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[Development and utilization of an immunoenzyme technic to diagnose arenavirus infections].

The possibility of using ELISA for the detection of arenavirus antigens in different organs of infected newborn white mice as well as in the culture fluids of arenavirus-infected cell cultures was demonstrated. The sensitivity of ELISA in antigen detection 100-200 times exceeds that of the CFT, and the time of antigen detection after inoculation of animals or cell cultures is much shorter. The use of ELISA block for the detection and titration of virus-specific antibody also demonstrated high sensitivity of this method as compared with the CFT.

Animals↗
PubMedDate not supplied

[Isolation of strains of the virus of hemorrhagic fever with renal syndrome in cell culture].

Four strains of hemorrhagic fever with renal syndrome (HFRS) virus were isolated from the lungs of Cl. glareolus caught in natural foci of HFRS in the European USSR. Preliminary experiments using enzyme-immunoassay (EIA) established the appurtenance of HFRS antigen in lung suspensions to the "western" serotype. Four strains were isolated in Vero-E6 cell culture after several blind passages and identified as the "western" serotype of HFRS virus. One stram originally isolated in Wistar rats and passaged in them 4 times and then adapted to Vero-E6 cells showed a closer antigenic relationship with the "eastern" HFRS virus serotype.

Animals↗
PubMedDate not supplied

[Results of a serological examination of amyotrophic lateral sclerosis patients].

Examinations of specimens from 12 patients with amyotrophic lateral sclerosis (ALS) by means of enzyme-labeled immunosorbent assay (ELISA) and solid-phase radioimmunoassay ( SPIRA ) demonstrated antibody to lymphocytic choriomeningitis virus (LCM) in the blood sera of 3 patients and antigens of LCM virus in sera of 2 other patients. LCM virus antigen was also found in organs of a patient who died of ALS. LCM virus was isolated from the serum of one patient positive for LCM antigen by inoculation of newborn white mice. The new isolate (the Kanta -220 strain) examined by electron microscope was shown to have some morphological differences from the museum strain CA-1371 of LCM virus available in the laboratory.

Adult↗
PubMedDate not supplied

[Biochemical nature of complement-fixing antigen of arenaviruses].

Soluble antigens of 6 arenaviruses (Tacaribe, Tamiami, LCM, Amapari, Machupo, and Junin) were isolated by gel chromatography in servachromium A-2. It was shown that practically the entire antigenic activity of the original virus-containing preparations in complement-fixation (CFT) and agar gel diffuse precipitation (AGDP) tests was due to the presence of soluble antigens in them. Antigenic relationships of the isolated soluble antigens were studied. Physicochemical characteristics of the soluble antigens were determined: buoyant density in cesium chloride solution, sedimentation properties, and sensitivity to RNase. The experimental results suggest that the soluble antigens are fragments of virion nucleocapsids.

Antigens, Viral↗
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[Results of serologic screening for hemorrhagic fever with kidney syndrome in Moldova].

Results of serologic screening of small mammals for antigen of the virus of hemorrhagic fever with the renal syndrome (HFRS) and of testing human sera for antibodies to this virus in Moldova are reviewed. A total of 9946 animals belonging to 22 species and blood sera of 792 healthy donors were examined in 1983-1990. HFRS virus antigen was detected in 30 animals of 9 species, with the highest incidence of the antigen in gray voles. Two serotypes of Hantavirus were found to circulate in small mammals: Puumala and Hantaan. Screening of healthy humans revealed antibodies to HFRS virus in 7.8%. Natural foci of HFRS were detected in 23 of the 44 administrative territories of the Republic situated in 5 landscape geographical provinces.

Animals↗
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[Genetic differentiation of hantaviruses using the polymerase chain reaction and sequencing].

Thirty-two hantavirus strains and 8 samples of lung tissue from rodents collected in different regions of Russia have been examined by molecular biological methods. Two methodological approaches have been employed for the study of genetic relationships between the viruses: nested PCR assay and common RT-PCR with subsequent direct sequencing of 200 and 365 base pair of G2 protein encoding regions of M-segment, respectively, and the resultant sequences were compared with those of the prototype hantavirus. The study revealed a mosaic pattern of distribution of different hantavirus genotypes on the territory of Russia.

Animals↗
PubMedDate not supplied

[Dot-blot analysis in laboratory diagnosis of hemorrhagic fever with renal syndrome].

A sensitive micro EIA utilizing antigen or antibody dotted onto nitrocellulose filters (Dot-ELISA, Dot-blot) has been developed for laboratory diagnosis of hemorrhagic fever with the renal syndrome (HFRS) by detecting the virus specific IgM and IgG in the sera of HFRS patients and the antigen in crude lung suspensions of wild rodents. Measurements of specific IgM and IgG in paired HFRS sera collected during the first month of the disease showed clear-cut seroconversion and 100% correlation with the results of immunofluorescent test. The results of antigen detection in lung suspensions of 605 wild rodents trapped in various regions of Russia were identical to standard ELISA results. This rapid and inexpensive test may be useful in early serologic diagnosis of HFRS and in field serological and epizootological studies.

Animals↗
PubMedDate not supplied

[The topographic zoning of natural HFRS foci in Russia].

Using large selections the unified system of landscape districting of HFRS natural foci with allocation of special geo-botanical provinces has been developed. This permits to avoid various deviations were found to appear during association of epizootiological and epidemiological indexes of separate towns and rural districts when estimating regional parameters. Adequacy of the offered system in confirmed by five-fold increase of the correlation between HFRS epizootiological parameters and antibody prevalence rate in humans. The steady maximum of all parameters was registered in the province situated in broad-leafed oak-line forests. Minimal values are found to correspond to one located in forest-steppe (with birch and asp forests) which poor fodder potential for rodents is well known. Other provinces between these ones are characterized by consecutive decrease of all index values according to the landscape type. According to estimated natural activity rate all the provinces are divided to three groups. The first one (antibody prevalence rate is above 5%) unites the high activity HFRS natural foci. Their common geographical location is on the territories with highest rodent population rates. The second group (antibody prevalence rate--2-4%) includes HFRS foci with average activity, and the third one (antibody prevalence rate is below 2%)--with low activity. The most of the last group provinces are situated on periphery or behind the bank vole living area.

Animals↗
PubMedDate not supplied

[Polyclonal immunoenzyme system for determining hantaviral antigens: assessment of specificity using monoclonal antibodies and the polymerase chain reaction].

Genus-specific monoclonal antibodies to nucleocapsid protein of Pumala virus and polymerase chain reaction were used to assess the specificity of a previously described polyclonal (based on human IgG to Pumala hantavirus) enzyme immunoassay (EIA) system for detecting hantavirus antigens. Parallel testing of crude lung suspensions from wild rodents trapped in different regions of Russia for hantavirus antigens and RNA showed 100% coincidence of the results of three tests. These data indicate a high specificity of polyclonal EIA system and its efficacy for screening of natural samples.

Animals↗
PubMedDate not supplied

[A system of immunoenzyme analysis using biotinylated monoclonal antibodies for typing hantavirus antigens].

Enzyme immunoassay with biotin-labeled monoclonal antibodies to Puumala virus was used for typing hantavirus antigens. The system is type-specific, that is, it detects Puumala virus only, which was demonstrated by typing 9 hantavirus antigens in infected Vero E5 cells and by epizootological analysis of an HFRS outbreak in the Yegoryevsk district of the Moscow region in November-December 1995. The suggested system may be used as an element of EIA screening of natural samples in analysis of the screening results.

Antibodies, Monoclonal↗
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[The antigenic differentiation of hantaviruses by using monoclonal antibodies].

85 hantavirus (HV) strains from Russia and other counties were examined by indirect fluorescent antibody test using monoclonal antibodies (MAbs) prepared against hantaviruses: Hantaan (Hantaan 76-118, A-9 strains), Seoul (SR-1, R-22 strains) and Puumala (Hallnas 83-223 strain). 68 HV strains were differentiated into five virus type groups: Hantaan, Puumala, Seoul, Prospect Hill and Belgrade-Dobrava. 17 strains were found to be antigenically closely related but distinct from Hantaan type (4 strains), Puumala (6 strains) and Prospect Hill (7 strains). The antigenic characteristics of these 17 strains suggested two supplementary antigenic subgroups of the Hantaan, two of Puumala and two of Prospect Hill.

Animals↗
PubMedDate not supplied

[Experience in using regression analysis for assessing the quality of the diagnosis of hemorrhagic fever with renal syndrome].

A new approach has been developed to evaluate the adequacy of HFRS clinical diagnosis, by using regression analysis of large selections. The HFRS morbidity rate and the antibody prevalence rate in man were viewed as a function and an argument of the function, respectively. An empiric model for one of the active HFRS endemic area (Saratov Province), characterizing the correlation between the immunity and morbidity rates has been elaborated. It calculates the theoretical morbidity level that corresponds to determine an immune portion of the population in each administrative area. The theoretical (counted) values were compared to the annually registered morbidity rates; their similarity has been estimated. Estimation of the adequacy of HFRS diagnosis in the examined region could have been admitted as satisfactory. However, various faults in the clinical identification of HFRS cases were found to occur in 14 of 44 districts of this region. Hyperdiagnosis was made in the most active HFRS natural foci (broad-leaved forests), but in the endemic areas being characterizes by moderate or low activity (forest-steppe and steppe districts). The results of the authors' calculations were shown to be generally in agreement with the data from the Regional Epidemiological Service reports which confirmed the adequacy of the proposed material.

Antibodies, Viral↗