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Biomedical subjects

P Gupta

Publications and source records attributed to P Gupta.

At least 379 records · Page 21Linked to original sources
PubMed1978

Detection of a precursor of bovine leukemia virus structural proteins in purified virions.

Gel filtration chromatography of disrupted bovine leukemia virus (BLV) resulted in the isolation of the 25,000 dalton major virion internal protein and two previously uncharacterized virion proteins of molecular weight 65,000 and 12,000 respectively. The 65,000 dalton protein does not bind to concanavalin A and its antigenicity is ether-resistant. Therefore, this polypeptide is different from the previously described glycoprotein associated with BLV. Radiommunoprecipitation and competitive radioimmunoassays indicated that the 65,000 molecular weight polypeptide shares antigenic determinants with the 25,000, 15,000, and 12,000 dalton BLV proteins, respectively. Thus, the 65,000 dalton polypeptide may represent the precursor of these three smaller virion proteins.

Chromatography, Gel↗
PubMed1978

An infectivity assay for the bovine leukemia virus based on the induction of the major internal virion antigen in susceptible cell cultures.

This report described the development of a 7-day infectivity assay for the bovine leukemia virus (BLV) which is based on the induction of the major internal virion antigen (p25) in susceptible indicator monolayer cell cultures. In this assay the antigen is detected in the indicator cells by the immunoperoxidase antibody technique using a monospecific anti-BLV serum. The immunoperoxidase infectivity assay (IPIA) is specific, quantitative, reproducible and more sensitive than the previously developed syncytia induction assay. The IPIA can be applied for the detection of BLV-infected cells and provides a reliable method for the direct diagnosis of BLV infection in cattle.

Antigens, Viral↗
PubMed1977

Comparison of the polypeptides of several strains of human cytomegalovirus.

Analysis of purified human cytomegalovirus (CMV) by sodium dodecyl sulphate-polyacrylamide gel electrophoresis revealed 32 polypeptides with mol. wt. ranging from 13,500 to 235,000. Similar analysis of purified preparations of four strains of CMV showed a remarkable similarity in polypeptide composition. Results indicate that the four strains may be related.

Cell Line↗
PubMed1977

Controlled field trial of a high-dose oral killed typhoid vaccine in India.

A controlled field trial of a modified vaccine containing Salmonella typhi, TY 2 strain, in a dose of 400 x 10(9) killed organisms per capsule, was carried out in schoolchildren aged 6-17 years. The children were followed up for 6-8 months. There were 66 cases of typhoid fever in the vaccine group (7312 children) and 54 in the control group (7292 children who had received a placebo). This difference is not statistically significant. The results confirm that, as found in earlier trials, oral typhoid vaccine, in the dosages used so far, gives no protection.

Administration, Oral↗
PubMed1975

Studies of temperature sensitive mutants of bacteriophage Qbeta, defective in both replication and translation.

Temperature sensitive mutants of bacteriophage Qbeta have been isolated which fail in the synthesis of their virus RNA at the non-permissive temperature (42 degrees C). Nine mutants have been studied in some detail. Cells infected with these mutants at 37 degrees C and incubated long enough to produce substantial amounts of Qbeta RNA cease Qbeta RNA replication when shifted to 42 degrees C. The mutants can be classified into 3 groups according to the amount of Qbeta RNA replicase activity exhibited in extracts from infected cells isolated at various times after shift to 42 degrees C: in group 1 mutants, enzyme activity is the same, regardless of the time of isolation after shift; in group 2 mutants enzyme activity increases with time of isolation after shift; in group 3 mutants, enzyme activity decreases with time of isolation after shift. Synthesis of all virus proteins is suppressed at 42 degrees C in cells infected with group 2 of group 3 mutants. In cells infected with group 2 mutants, synthesis of Qbeta RNA replicase subunit beta is increased, but synthesis of other virus proteins is depressed at 42 degrees C. The inhibition of virus RNA and protein synthesis is reversible. A detailed analysis of these experiments suggests that a defective Qbeta RNA replicase is involved in the inhibition of both virus RNA and protein synthesis.

Coliphages↗