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Biomedical subjects

L Levine

Publications and source records attributed to L Levine.

At least 289 records · Page 16Linked to original sources
PubMed1973

Serological relatedness of bacterial deoxyribonucleic acid polymerases.

A number of bacterial species have been surveyed for serological activities with antiserum to Escherichia coli B deoxyribonucleic acid (DNA) polymerase I (EC 2.7.7.7.). The degree of serological cross-reaction is taken as a measure of relatedness of both the enzyme molecules from various species and the bacterial species themselves. Extracts were assayed by complement fixation only after treatment with deoxyribonuclease, since DNA bound to DNA polymerase alters the serological activity of the enzyme. Antiserum to E. coli DNA polymerase I did not react with either purified E. coli DNA polymerase II or the phage T4-induced DNA polymerase.

Animals↗
PubMed1973

The early primary immune response to absorbed tetanus toxoid in man: A study of the influence of antigen concentration, carrier concentration, and sequence of dosage on the rate, extent, and persistence of the immune response to one and to two doses of toxoid.

A quantitative study was performed to determine the effect of toxoid concentration and aluminium salt concentration on the primary immune response (PIR) and the secondary response induced by tetanus toxoid in human volunteers. Four toxoid preparations having 5-fold differences in toxoid concentration, aluminium salt concentration, or both, were administered to four comparable groups of human volunteers. Antitoxin titres in the serum of each volunteer were determined at intervals. The PIR was found to be a function of the antigen concentration, the mineral concentration, and the interaction of both. The secondary response was a function of the antigen concentration; increase in mineral adjuvant concentration had no significant effect. The data suggested that the higher the post-secondary response, the slower the rate of decline over the ensuing 10 months. The distribution of primary responses at day 28 tended to be bimodal. The response to the best preparation suggested that a single-dose toxoid might be developed to immunize populations that may be difficult to retrieve for multiple injections.

Adsorption↗
PubMed1972

Evidence that the bone resorption-stimulating factor produced by mouse fibrosarcoma cells is prostaglandin E 2 . A new model for the hypercalcemia of cancer.

A transplantable mouse fibrosarcoma, HSDM(1), produces a potent bone resorption-stimulating factor. The factor can be extracted from the tumor tissue and harvested from the medium of clonal strains of HSDM(1) tumor cells growing in monolayer culture. It has several chemical and biological properties of a prostaglandin. Using radioimmunoassay techniques, we have shown that HSDM(1) cells synthesize and secrete large quantities of prostaglandin E(2) (PGE(2)). The specific bone resorption-stimulating activity of the HSDM(1) factor extracted from the tumor is high and approximately equal to that of PGE(2) as measured in a bone tissue culture system in vitro. Indomethacin, a potent inhibitor of PGE(2) synthesis in HSDM(1) cells, also inhibits production by the cells of the bone resorption-stimulating factor, and has no detectable nonspecific effects on the bone culture assay system. Mice bearing the HSDM(1) tumor have higher levels of both calcium and PGE(2) in serum than control mice. We conclude that PGE(2) is the bone resorption-stimulating factor produced by HSDM(1) tumor cells, and that secretion of PGE(2) by the tumor in vivo accounts for the relative hypercalcemia observed in tumor-bearing animals. The HSDM(1) tumor cell system constitutes a new model for studying the pathogenesis of hypercalcemia associated with certain malignant tumors.

Animals↗