The finding that 7r,8t-dihydroxy-9,10-t-oxy-7,8,9,10-tetrahydrobenzo(a)pyrene (BPDE-I) is stabilized against hydrolysis by binding to cellular membranes suggested that nucleophilic compounds which would colocalize with BPDE-I in membranes might inhibit the deleterious biological effects of BPDE-I. We have explored the possibility that hydrophobic, sulfhydryl-containing compounds might provide s...

Introduction: Heavy ions are nucleus of elements of iron, argon, carbon and neon that all carry positive electrical charges. For these particles to be useful in radiotherapy they need to accelerated to high energy by more than thousand mega volts. Also the cosmic environment is considered to be a complicated mixture of highly energetic photons and heavy ions such as iron. Therefore, the health ...

Rat and human colonic mucin glycoproteins bind to the Gal/GalNAc adherence lectin on the surface of Entamoeba histolytica in vitro, thus inhibiting the organism from adhering to and lysing the target cells. Human colonic mucin glycoproteins were isolated by Sepharose 4B gel filtration chromatography, they were proteolytically degraded with trypsin, pronase, and papain, and the glycoprotein frac...

The potent tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) was tested for its ability (a) to induce sister chromatid exchange, (b) to increase the rate of transition at the adenine phosphoribosyltransferase (apt) locus from the presumptive heterozygous state ((+/- to the homozygous state (-/ - or -), and (c) to enhance the frequency of mutations expressed after ultraviolet radiation m...

The amount of crude Campylobacter jejuni enterotoxin present in culture products was quantitated by comparing the response of these preparations with that of pure Escherichia coli heat-labile toxin (LT) in the Chinese hamster ovary assay and in enzyme-linked immunosorbent assays that used GM ganglioside or antisera to LT or both. Maximum C. jejuni enterotoxin production was achieved by growth a...

The relationship between cell killing and the binding of the anticancer drug cis-diamminedichloroplatinum(II) (cis-DDP) to DNA was studied in six mammalian cell lines. Two of the human cell lines (COV413B) were of the same origin, comprising one sensitive to cis-DDP and the other with induced resistance to the drug. The four other lines, two rodent (RIF-1, Chinese hamster ovary) and two human (...

Mitomycin C is an alkylating agent used in cancer chemotherapy that shows some specificity towards hypoxic cells. The therapeutic effects of this compound are thought to result from its metabolic activation by enzymes such as NADPH:cytochrome P-450 reductase. In a previous report we described a Chinese hamster ovary cell line resistant to mitomycin C, which had a decreased NADPH:cytochrome P-45...

The relationship between cell killing and the binding of the anticancer drug m-diamminedichloroplatinum(II) (c/'s-DDP) to DNA was studied in six mammalian cell lines. Two of the human cell lines (COV413B) were of the same origin, comprising one sensitive to m-DDP and the other with induced resistance to the drug. The four other lines, two rodent (RIF-1, Chinese hamster ovary) and two human (A27...

In Chinese hamster ovary cells and in normal and transformed rat embryonic fibroblasts, survival as a function of time at 42.4 degrees was dependent upon the rate of heating from 37 degrees to 42.4 degrees. Unexpectedly, the untransformed rat fibroblasts were more heat sensitive than were the transformed cells, and the protective effect of slow rates of heating upon survival at 42.4 degrees was...

Chinese hamster ovary cells were exposed to the sulfhydryl compound cysteamine at different temperatures (5 degrees C, 37 degrees C, 44 degrees C) at concentrations known to generate activated oxygen species. At 37 degrees C, the cellular glutathione (GSH) content increased linearly over the time of drug exposure (2 h) as compared to untreated cells or to cells kept at 5 degrees C during drug t...