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R Lowy

Publications and source records attributed to R Lowy.

76 records · Page 5Linked to original sources
PubMedDate not supplied

Determination of a virtually non-carcinogenic dose.

The various mathematical models of the dose-response relationship are briefly reviewed and it is concluded that the Weibull and gamma-multihit models are at present the best ones. They permit the computation of a 'virtually safe dose', for which the carcinogenic risk to man is reasonably negligible, but because of the unknown mechanism of the background response, the models should be used in a mixed form. A modified Crouch and Wilson approach is proposed to evaluate the risk from an actual environmental dose. This takes into account the various uncertainties in risk computations, and results in the application of a safety factor when extrapolating from animals to man.

Animals↗
PubMedDate not supplied

Effects of interferons alpha,beta,gamma alone or in combination on the phenotype of human colon carcinoma cells.

The ability of interferons (IFNs) alpha,beta,gamma, alone or in combination, to induce reversion of the phenotype of cloned human colon carcinoma cells during long-term treatment was studied. The phenotypic characteristics examined were proliferation, cellular aggregation and tumorigenicity. The combination of IFN-beta and IFN-gamma showed more antiproliferative activity than that of IFN-delta and IFN-gamma or of either IFN alone. All IFN treatments induced cellular aggregation which was associated with the appearance of brush border microvilli. Both antiproliferative effects and formation of cellular aggregates persisted only in the presence of prolonged treatment with combinations of IFNs alpha,beta with IFN-gamma. No significant differences in the binding of IFN were found between short-and long-term IFN treated cells. Treatment with IFN-beta appeared most effective in decreasing, but not completely suppressing, tumorigenicity.

Animals↗