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Biomedical subjects

S E Grossberg

Publications and source records attributed to S E Grossberg.

At least 91 records · Page 5Linked to original sources
PubMed1975

The influence of physicochemical factors on the thermal inactivation of murine interferon.

The degradation of biological activity of virus-induced murine interferon was determined in linear nonisothermal and multiple isothermal tests. The stabilizing effect of pH during heating on interferon in solution was greatest at low pH, such that pH 2 greater than pH 5 greater than pH 7 greater than or equal to pH 9; freeze-dried preparations of interferon were also more heat-stable at acid pH than at neutral pH. Heat stability was a function of the H+-ion concentration rather than the ionic composition of the buffer; interferon solutions containing monovalent cations with different ionic radii had similar heat stability. A change in the H+ ion concentration was a critical event during the cooling of heated interferon: a shift in the direction of acidity contributed to stability whereas a shift towards alkalinity led to inactivation. The rate of cooling of heated interferon significantly influenced its residual activity. Rapid cooling and sudden freezing decreased the residual activities of interferons at pH 2 and 9 more than "normal" cooling, an effect not observed at pH 7. Interferon heated to 80degree C could not be reactivated at 40degree C or 55degree C. Interferon of higher apparent molecular weight was more heat-stable than that with lower apparent molecular weight. It is postulated that the physicochemical alterations in the aqueous environment significantly affecting the stability of interferon operate by producing changes in the size and/or conformation of interferon molecules. A model is proposed that relates thermal inactivation to different possible molecular states of interferon.

Animals↗
PubMed1975

The neuraminidase yield-reduction bioassay of human other interferons.

The production of neuraminidase by the recombinant influenza virus X7(F1) in human monkey, rabbit, hamster, mouse, and chicken cell cultures is inhibited by interferon. Described is a new enzyme assay for neuraminidase that can be applied to the bioassay of interferons. The advantages of this interferon bioassay are its sensitivity, reproducibility, rapidity, and convenience.

Animals↗
PubMed1971

Repression of interferon action: induced dedifferentiation of embryonic cells.

Cells cultured from young (6-day) chicken embryos differ from those of older (13-day) embryos in having a greater susceptibility to infection by certain viruses and a considerably lesser sensitivity to the action of interferon. These circumstances parallel those observed in the intact embryo. The addition of a small percentage of cells from young embryos alters the response of cells cultured from older embryos by increasing viral susceptibility sevenfold and decreasing sensitivity to interferon 25-fold. We postulate that a repressor which inhibits the expression of interferon in older embryonic cells is elaborated by cells from young embryos.

Aging↗