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Biomedical subjects

R Marusyk

Publications and source records attributed to R Marusyk.

12 recordsLinked to original sources
PubMed1993

Development of the polymerase chain reaction for diagnosis of chancroid.

The published nucleotide sequences of the 16S rRNA gene of Haemophilus ducreyi were used to develop primer sets and probes for the diagnosis of chancroid by polymerase chain reaction (PCR) DNA amplification. One set of broad specificity primers yielded a 303-bp PCR product from all bacteria tested. Two 16-base probes internal to this sequence were species specific for H. ducreyi when tested with 12 species of the families Pasteurellaceae and Enterobacteriaceae. The two probes in combination with the broad specificity primers were 100% sensitive with 51 strains of H. ducreyi isolated from six continents over a 15-year period. The direct detection of H. ducreyi from 100 clinical specimens by PCR showed a sensitivity of 83 to 98% and a specificity of 51 to 67%, depending on the number of amplification cycles.

Base Sequence↗
PubMed1989

Infection of human peripheral blood mononuclear cells with a temperature-sensitive mutant of measles virus.

A stable temperature-sensitive mutant of measles virus (MV ts38) was used to study the mechanism of virus-mediated immune suppression of peripheral blood mononuclear cells in vitro. Both unstimulated and phytohemagglutinin-stimulated cultures released infectious virus at 32 degrees C, whereas no virus was released at 37 degrees C, although both viral RNA and viral proteins were synthesized. However, the response of the lymphoid cells to phytohemagglutinin, concanavalin A, and herpes simplex virus antigen was decreased in the presence of MV ts38 at 37 degrees C. The viability of infected cells was not diminished, therefore excluding cell death as a reason for immunosuppression. Interleukin 2 did not play a role in the inhibitory effect of MV ts38. Antibodies to alpha interferon partially reversed the inhibitory effect of the virus infection on lymphocyte mitogenesis, thus implying that alpha interferon plays a role in the immunosuppression. Depletion experiments indicated that adherent cells play a greater role in the measles virus-induced immunosuppression than nonadherent cells. However, monocyte maturation to macrophages had no effect on the degree of immunosuppression.

Cell Differentiation↗
PubMed1988

Impaired interleukin 1 and interleukin 2 production following in vitro abortive infection of murine spleen mononuclear cells by Semliki Forest virus.

The effect of Semliki Forest virus (SFV) infection of murine spleen mononuclear cells was investigated in vitro. A small percentage of spleen macrophages expressed viral antigens, but no infectious virus particles were released, indicating an abortive-type infection. Wild-type SFV infected a higher percentage of macrophages than the attenuated, demyelinating mutant A7. The proliferation of spleen mononuclear cells under Con A stimulation was inhibited by the viral infection. The supernatant (SN) harvested from infected and Con A-stimulated spleen adherent cells could not stimulate thymocytes in an interleukin 1 (IL-1) assay and indomethacin treatment of infected cultures had no effect. The stimulatory effect of SN from noninfected cultures in the IL-1 assay was reduced when SN from infected cultures was added, suggesting the presence of an IL-1 inhibitor. Interleukin 2 (IL-2) production by splenocytes also decreased after viral infection, but exogenous IL-2 restored the response to Con A stimulation of infected spleen cells. This study demonstrates that abortive SFV infection of spleen macrophages has an immunosuppressive effect which may lead to an aberrant immune regulation.

Animals↗
PubMed1988

Measles virus strain-dependent variation in outcome of infection of human blood mononuclear cells.

Eight measles virus strains including four subacute sclerosing panencephalitis (SSPE) isolates were compared on the basis of their growth characteristics in human peripheral blood mononuclear cells and effect on mitogen-stimulated lymphocyte proliferation. The Edmonston strain virus and some other strains of measles virus replicated in phytohaemagglutinin (PHA)-stimulated lymphocytes and released high titres of infectious virus into the culture medium. Inhibition of DNA synthesis was relatively low at the beginning of lymphocyte proliferation and could be detected only at high multiplicity of infection. Three to 4 days after initiation of proliferation a strong inhibition was seen also in cultures infected with low doses of virus, and was apparently related to the production of high titres of new infectious virus. Some virus strains originally isolated from SSPE patients produced only a small amount of infectious virus in lymphocytes at 37 degrees C but had a very strong inhibitory effect on lymphocyte proliferation leading to early cell death. The inhibitory effect was found over a wide range of virus concentrations, but was strictly dose-dependent and no increase in inhibition with low multiplicities of infection could be seen with longer culture times. The amount of interferon induced by different strains varied from 400 to 6400 international units/ml but the amount of interferon produced in the cultures did not correlate with the inhibitory effect on proliferation or with the amount of released new infectious virus. The Hallé measles strain, originally isolated from an SSPE patient, differed most from the Edmonston strain in its characteristics, and was studied in greater detail. Although only a small amount of infectious virus was produced, the Hallé strain had a very strong inhibiting effect on the proliferation of PHA-stimulated lymphocytes, and extensive syncytium formation was seen leading to cell death within 3 days.

Animals↗
PubMed1986

Nuclear accumulation of measles virus nucleoprotein associated with a temperature-sensitive mutant.

A measles virus (MV) Lec strain conditional-lethal (temperature-sensitive) mutant, designated MV ts38, has been isolated from 5-fluorouracil-mutagenized stock. The mutant has been characterized with regard to growth characteristics at 32 degrees C (permissive temperature) and 39 degrees C (non-permissive temperature). Virus-specific RNA transcription and/or translation appeared to be blocked at the non-permissive temperature as no virus-specific products could be detected by biochemical or immunological procedures. Following initiation of viral replication at 32 degrees C, with subsequent shift-up to 39 degrees C, presynthesized nucleoprotein (NP) was transported to, and accumulated in the cell nucleus whereas other viral proteins could not be detected there. A corresponding accumulation of NP in the nucleus is most often seen in association with MV neurotropic subacute sclerosing panencephalitis isolates in vivo and in vitro.

Animals↗
PubMed1979

Biophysical and serologic comparison of four equine adenovirus isolates.

Four equine adenovirus isolates have been characterized with regard to their biophysical and serologic properties. Electron microscopic studies demonstrated that purified virions have a typical adenovirus morphologic characteristic, with 50-nm-long fiber projections at each vertex of an 80-nm-diameter icosahedron. Extracted viral DNA was found to be a linear duplex of molecular weight 21 to 22 x 10(6). All four isolates were found to have a buoyant density in CsCl of 1.346 +/- 0.002 g/ml. Hexon structural components prepared from each isolate were shown to carry the same relative net charge, as judged from anion exchange elution profiles. Sodium dodecyl sulfate (sodium lauryl sulfate)-polyacrylamide gel electrophoresis revealed that the four isolates were composed of which the electrophoretic migration pattern was distinct from that of a human adenovirus reference. Serologic data (serum-neutralization and hemagglutination-inhibition tests) did not reveal any distinct antigenic diversity among the four isolates. On the basis of data obtained in this study, it is proposed that equine adenovirus isolates thus far available do, in fact, constitute a single serotype.

Adenoviridae↗