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Biomedical subjects

I Sarov

Publications and source records attributed to I Sarov.

At least 145 records · Page 8Linked to original sources

Detection of IgG antibodies specific for measles virus by enzyme-linked immunosorbent assay (ELISA).

A solid-phase, enzyme-linked immunosorbent assay (ELISA) for determination of IgG antibodies against measles virus is described. The assay utilized antigen-coated polystyrene microplates. The antigen consisted of a sonicated extract of measles-infected Vero cells. Goat and anti-human IgG-peroxidase conjugate was used to detect human IgG bound to viral antigen. Sera taken from 63 healthy adults, 11 young children and 36 patients were evaluated for their IgG titer against measles virus. Comparison of results obtained by ELISA with those obtained by hemagglutination-inhibition (HI) assay or by complement fixation showed good agreement between the tests. The geometric mean titer (GMT) for healthy adults was 753 for ELISA and 32.8 for HI. If these averages are taken as a measure of comparison, then ELISA is approximately 23 times more sensitive than HI. ELISA technique is rapid to perform and could be recommended for routine diagnosis.

Adult↗

Stimulation of human lymphocytes by cytomegalovirions and dense bodies.

Lymphocytes from healthy adult individuals were examined for their ability to incorporate thymidine in the presence of cytomegalovirus (CMV) and dense bodies. It was found that lymphocytes from donors with antibodies to CMV were stimulated to incorporate thymidine-14C both by preparation of CMV and CMV dense bodies. Lymphocytes from CMV seronegative donors did not respond. Dilution experiments and the dose-response curve indicate that the stimulation induced by the dense body preparation was not caused by the small amounts of contaminating CMV particles. These results indicate that in healthy human adults there is a correlation between CMV seropositivity and in vitro lymphocyte transformation, induced by either CMV or by dense bodies.

Adult↗

Detection of antibodies to varicella zoster virus by radioimmunoassay and enzyme immunoassay techniques.

An enzyme assay for the detection of antibodies to varicella-zoster membrane antigen (IPAMA) and a solid phase radioimmunoassay (RIA) which utilizes infected cell lysates as antigen are described. The results have been compared with those obtained by the indirect fluorescent antibody to membrane antigen (IFAMA) technique. It was found that IPAMA was equal in sensitivity to IFAMA. No cross-reactivity was found with other herpes group viruses. The IPAMA appears to give objective results, is easily and rapidly performed, and is recommended as a routine test for serological diagnosis of varicella-zoster infection. The RIA method is about 100 times more sensitive than IPAMA and IFAMA. The RIA is specific and has the potential of determining lower levels of antibody than other serological methods currently in use.

Antibodies, Viral↗

Use of purified cytomegalovirus as antigen in the complememt fixation test.

Crude cytomegalovirus (CMV) antigen and purified CMV antigen were used in tests for complement-fixating (CF) antibodies in sera from 7 patients with CMV infection. CF antibodies to purified CMV appeared later than the other CF antibodies tested and parallel to neutralizing antibodies.

Antibodies, Viral↗

Human cytomegalovirions and dense bodies: glycopeptide analysis and mechanism of cell rounding and polykaryocytosis.

Human cytomegalovirions and dense bodies labeled with [14C]glucosamine were analyzed by means of sodium dodecyl sulfate-urea polyacrylamide gel electrophoresis and autoradiography. The same glycopeptide composition was found in both cytomegalovirions and dense bodies. These consisted of at least 11 glycopeptides which ranged in molecular weight from 46,500 to over 170,000 daltons. Addition of purified human cytomegalovirus (CMV) at high multiplicity to confluent monolayers of human fibroblasts produced cell rounding and polykaryocytes containing 3 to 150 nuclei. The cell rounding was induced by the cytomegalovirions, but not by the cytomegalo dense bodies. Inhibition of protein synthesis, but not of DNA synthesis, prevented this effect, suggesting that cell rounding is protein mediated. In contrast, the formation of polykaryocytes by CMV was not affected by inhibitors of protein synthesis. UV irradiation of the virus, which abolishes infectivity, does not affect its fusion properties. CMV dense bodies, which contain very little or no DNA, also produce cell fusion although this effect is less pronounced than with virions. CMV-induced polykaryocytosis therefore appears to be a direct result of the interaction of cells with the input viral particles, a phenomenon usually referred to as early polykaryocytosis.

Cell Nucleus↗

Fractionation of RNA from tetahymena by affinity chromatography on poly-U-Sepharose.

Exponential growing Tetrahymena pyriformis organisms were labelled with (3H) uridine or (3H) adenosine. The labelled RNA was extracted and isolated by affinity chromatography on poly-uridylic-acid sepharose and further analysed by means of sucrose gradient centrifugation and RNase digestion. Experimental evidence proved the existence of RNase resistant poly adenylic-acid fragments in the RNA of Tetrahymena cells. This poly adenylic-acid segment has a sedimentation rate of 4-5 S and would be localised in the 10-12S region of the RNA which is probably the m-RNA.

Animals↗

Deoxyribonucleic acid-dependent ribonucleic acid polymerase activity in purified trachoma elementary bodies: effect of sodium chloride on ribonucleic acid transcription.

Highly purified trachoma elementary bodies (T'ang strain), incubated in the presence of the four nucleoside triphosphates [Mg(2+), Mn(2+), 2-mercaptoethanol, tris(hydroxymethyl)aminomethane buffer (pH 7.5)] were found to incorporate (3)H-uridine triphosphate (UTP) into ribonucleic acid (RNA) molecules. Eighty-seven per cent of the labeled molecules were sensitive to ribonuclease treatment. In vitro RNA synthesis was almost completely inhibited by actinomycin D. Rifampin was also inhibitory, but allowed some initial RNA synthesis before complete inhibition occurred. When the reaction mixture lacked Mn(2+), trachoma elementary bodies synthesized, for a limited period, high-molecular-weight RNA species (23 to 24S, 16 to 17S, and 10 to 11S). Addition of 0.2 m NaCl to the same reaction mixture stimulated and prolonged (3)H-UTP incorporation into the same radioactive RNA species. Addition of 0.001 m Mn(2+) instead of NaCl also stimulated (3)H-UTP incorporation but prevented the synthesis of the high-molecular-weight RNA species.

Amnion↗

Trachoma agent DNA.

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Centrifugation, Density Gradient↗