Antiproliferative effect of the tripeptide pyroGlu-Phe-GlyNH2 on murine melanocytes: transitory delay of cell growth in vitro and the cell cycle specificity.

Cell growth and differentiation in melanocyte cell populations are regulated by a wide range of bioactive substances. Recently, the tripeptide pyroGlu-Phe-GlyNH2 which inhibits melanocyte growth in vitro was identified in both murine nontransformed melanocytes and malignant melanoma cells. The present study was undertaken to investigate the cell cycle specificity as well as the growth inhibitory profile of the tripeptide after a single or repeated administration to melanocyte cultures.

Paramyxovirus SV5 and multiple sclerosis.

Multiple sclerosis is commonly associated with a local humoral immune response within the central nervous system. A hallmark of this intrathecal response is the presence of electrophoretically demonstrable oligoclonal bands of IgG in the cerebrospinal fluid (CSF) of up to 95% of patients. Observations indicating that a major part of the CSF IgG in some patients may represent antibodies to SV5, a simian virus closely related to human parainfluenza type 2 virus, were recently reported by Goswami et al.

DNA synthesis in cultured adult rat hepatocytes: effect of serum and calcium.

We have investigated the influence of serum and of varying Ca2+ concentrations on the DNA synthesis in primary monolayer cultures of adult rat hepatocytes, using a defined basic medium. Supplementation of the medium with 10% horse serum did not significantly affect the time course of the DNA synthesis induced by insulin and epidermal growth factor. Dose effect curves showed that serum moderately sensitized the cells to low concentrations of insulin and slightly sensitized them to epidermal growth factor, but was not required for full responses to maximal concentrations of the hormones.

A simple medium for the study of hepatocyte growth in culture under defined conditions.

The combination (1:1) of Dulbecco's modified Eagle's medium and Waymouth's medium MAB 87/3 was found to provide favorable conditions for serum-free culture and growth of adult rat hepatocytes. In this simple medium, a majority of hepatocytes stimulated by epidermal growth factor plus insulin entered S phase and divided, with a normal (13 h) interval between DNA synthesis and cell division. The proliferative response did not require extra substratum or the presence of serum, even during cell isolation and plating.