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Biomedical subjects

G Spira

Publications and source records attributed to G Spira.

68 records · Page 4Linked to original sources

Modified radioimmunoassay for murine sarcoma-leukemia virus group-specific antigen.

Iodination of disrupted Moloney strain murine sarcoma-leukemia virus resulted in labeled group-specific (gs) protein which was subsequently purified on an isoelectrofocusing column. This iodinated purified gs antigen, prepared from a relatively small quantity of purified virus, was used in a radioimmunoassay. A radioimmunoassay inhibition method was developed so that antibody specific for mammalian C-type gs antigen could be measured in undiluted or low dilutions of test serum without altering the known reagents of the test. The gs antigen isolated from purified Moloney strain murine sarcoma-leukemia virus has an isoelectric point (pH 5.95) which is significantly lower than that reported for other murine leukemia viruses.

Antibodies, Viral↗

Expression of the major internal viral polypeptide in cells transformed by wild-type and temperature-sensitive murine sarcoma virus.

Phenotypic expression of the murine intraspecies and interspecies antigenic determinants of the major type C viral structural 30,000-dalton polypeptide, p30, was measured by radioimmunoassay inhibition in cell lines from different species. Uninfected normal rat kidney (NRK) cells did not contain detectable levels of murine intraspecies and interspecies p30 antigen, whereas rat cells transformed by and producing murine sarcoma virus (MSV)-Moloney leukemia virus (M-MSV-MuLV) contained high levels of both murine intraspecies and interspecies p30 antigen. Significant amounts of murine intraspecies and interspecies p30 antigen were detected in wild-type MSV-transformed nonproducer NRK cells. The control of p30 antigen expression was examined in temperature-sensitive MSV-transformed nonproducer cells [NRK(MSV-1b)] which are cold sensitive for maintenance of the transformed phenotype. Both murine intraspecies and interspecies p30 antigens were detected in NRK(MSV-1b) cells when grown at the permissive (39 C) or nonpermissive (33 C) temperature, suggesting that p30 antigen expression is not correlated with maintenance of the transformed phenotype. The results demonstrate that previously undetectable p30 antigens are expressed in MSV-transformed nonproducer NRK cells, and suggest that the expression of p30 antigen may be a useful marker for viral gene expression in mammalian cells.

Animals↗

Papovavirus structural polypeptides: comparison of human and rabbit papilloma viruses with simian virus 40.

A comparative study of the structural polypeptides of purified human papilloma virus, rabbit papilloma virus, and simian virus 40 (SV40) was performed by electrophoretic analysis on 10% polyacrylamide gels containing sodium dodecyl sulfate either by Coomassie blue staining or by electrophoresing purified virus preparations labeled with radioactive iodine. Analysis of human papilloma virus on stained gels revealed 6 bands with a major polypeptide of molecular weight 63,000 daltons comprising 60% of the virion protein. Analysis of rabbit papilloma virus on stained gels revealed 5 bands with a major polypeptide of molecular weight 60,000 daltons comprising 48% of the virion protein. Under conditions which yielded 6 polypeptides for SV40, in agreement with published data, 4 and 7 polypeptides were regularly detected in iodinated preparations of human and rabbit papilloma viruses, respectively. Isoelectrofocusing of iodinated virions revealed isoelectric points of pH 3.7 for SV40 and pH 4.0 for both rabbit and human papilloma viruses.

Animals↗

Non symptomatic hypercalcemia in a myeloma patient.

An asymptomatic hypercalcemic IgG-Kappa myeloma patient is presented. A calcium-IgG complex was isolated and purified from the serum by column chromatography. Following further purification on a Sepharose protein A column, the IgG-Kappa molecule did not contain any detectable amount of calcium, indicating that calcium is loosely bound to IgG. The monoclonal IgG demonstrated a strong calcium binding capacity in vitro. The calcium-IgG complex in the serum was shown not to be saturated and thus could absorb more ionized calcium. In view of the presence of an abnormal monoclonal IgG capable of binding excess calcium, and the fact that the asymptomatic patient did not respond to the antihypercalcemic drugs, the treatment was stopped.

Antineoplastic Agents↗

Newcastle disease virus pathogenesis in the respiratory tract of local or systemic immunized chickens.

Establishment of selective immunity, local or systemic, made it possible to evaluate the pathogenesis of Newcastle disease virus (NDV) in the respiratory tract of chickens that were previously immunized with beta-propiolactone-inactivated antigen. NDV was inoculated intranasally or intramuscularly to chickens in different states of immunity (local or systemic). Humoral antibodies protected chickens against intranasal as well as intramuscular infection. Local antibodies, on the other hand, conferred immunity only against intranasal challenge. The respiratory tract supported multiplication of the virus, producing a self-limited subclinical infection. Replication of the virus in this system was negligible, playing only a minor role in the pathogenesis of the disease.

Administration, Intranasal↗

Noninvasive evaluation of extra-/intracranial anastomoses by dynamic CT and Doppler sonography.

In order to find a reliable noninvasive method of evaluating patency and function of extra-/intracranial arterial bypass, pre- and postoperative angiograms were compared with the results of pre- and postoperative dynamic computed tomographic (CT) scans and Doppler sonographic findings. Doppler sonography alone is a reliable method for determining patency and relative function of the anastomosis. Dynamic CT permits qualitative evaluation of cerebral perfusion and, by comparison of pre- and postoperative scans, assessment of the contribution of the extra-/intracranial bypass to the circulation of the affected hemisphere. Combined use of Doppler sonography and dynamic CT provides sufficient information about the postoperative status of cerebral perfusion to obviate the use of conventional angiography in routine cases.

Adult↗