Cells from patients with xeroderma pigmentosum, complementation group A (XPA), are known to be defective in repair of pyrimidine dimers and other forms of damage produced by 254-nm ultraviolet (UVC) radiation. We have isolated a DNA endonuclease, pI 7.6, from the chromatin of normal human lymphoblastoid cells which recognizes damage produced by UVC light, and have introduced this endonuclease i...

The rates of cell proliferation and cell loss in conjunction with the differentiation status of a tissue are among the many factors contributing to carcinogenesis. Nongenotoxic (non-DNA reactive) chemicals may affect this balance by increasing proliferation through direct mitogenesis or through a regenerative response following loss of cells through cytotoxic (oncotic) or apoptotic necrosis. In...

Rad51 protein of Saccharomyces cerevisiae is a structural homolog of the Escherichia coli recombination enzyme RecA. In yeast, the Rad51 protein is required for mitotic and meiotic recombination and for repair of double-strand breaks in DNA. We have used antibodies raised against the homologous human protein, HsRad51, expressed in E. coli, to visualize the spatial distribution of the protein in...

Background Emergency departments are the leading providers of unscheduled care with over 85% of patients discharged home after their visit. Discharge communication with parents has been shown to vary across setting and illness presentation. Emergency practice environments are chaotic by nature and characterized by multiple interruptions. The primary goal of this synthesis project was to underst...

Several approaches were used to probe aspects of the mechanism of acrylonitrile carcinogenicity in rats. Acrylonitrile did not appear to increase the rate of DNA synthesis resulting from tissue injury and regeneration in liver or brain, the latter being a target organ. The chemical did cause unscheduled DNA synthesis in rat liver but not brain. The epoxide of acrylonitrile, 2-cyanoethylene oxid...

The synthetic steroid cyproterone acetate (CPA) has been reported to be hepatogenotoxic in female rats depending on sex-specific expression of a hydroxysteroid sulfotransferase (HST) which is involved in the bioactivation of CPA to reactive metabolites. In the present study the ability of CPA to initiate apoptosis in rat hepatocytes in vitro was investigated with respect to sex-specific effects...

We previously developed a quantitative autoradiographic tech nique with special forceps for measuring unscheduled DNA synthesis (UDS) in mouse skin after treatment with ultraviolet light in vivo. By this method, we investigated the relationship between the protective role of melanin and UV-induced DNA repair in black-and-white guinea pigs. Flat areas containing a sharp border between pigmented ...

12-O-Tetnadecanoyl-phonbol-13-acetate (TPA) and phon bol were tested in Chinese hamster cells for their effects on mutagenesis (resistance to 6-thioguanine and to ouabain), DNA repair, and survival after ultraviolet (UV) irradiation. Recovery of 6-thioguanineand ouabain-resistant colonies was significantly increased by TPA treatment and, to a lessen extent, by phonbol in UV-innadiated cells. Mo...

We previously developed a quantitative autoradiographic technique with special forceps for measuring unscheduled DNA synthesis (UDS) in mouse skin after treatment with ultraviolet light in vivo. By this method, we investigated the relationship between the protective role of melanin and UV-induced DNA repair in black-and-white guinea pigs. Flat areas containing a sharp border between pigmented a...