OBJECTIVES To investigate if oral omeprazole application induces cancers of fore and glandular stomach in mice. METHODS A total of 66 eligible male mice were randomly divided into 6 groups, which were treated with control reagent, low (6 mg/kg) and high dose omeprazole (30 mg/kg), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG, 100 mg/L water), and MNNG plus low and high dose omeprazole, respecti...

SUMMARY The promoting effect of sodium cholate or sodium cheno-deoxycholate on colon carcinogenesis was studied in fe male F344 germ-free and conventional rats. Both germ-free and conventional rats received intrarectal instillations of N-methyl-A/'-nitro-/V-nitrosoguanid¡ne (MNNG) for 2 weeks (total dose, 8 mg/rat) and then intrarectal doses of sodium cholate or sodium chenodeoxycholate (20 mg...

(total dose, 8 mg/rat) and then intrarectal doses of sodium cholate or sodium chenodeoxycholate (20 mg/rat/dose) three times a week for 46 weeks; other groups received MNNG for 2 weeks and vehicle thereafter for 46 weeks or bile acids alone for 48 weeks. Sodium cholate or sodium chenodeoxycholate increased MNNG-induced adenocarcinomas and adenomas in germ-free rats, whereas in conven tional rat...

(total dose, 8 mg/rat) and then intrarectal doses of sodium cholate or sodium chenodeoxycholate (20 mg/rat/dose) three times a week for 46 weeks; other groups received MNNG for 2 weeks and vehicle thereafter for 46 weeks or bile acids alone for 48 weeks. Sodium cholate or sodium chenodeoxycholate increased MNNG-induced adenocarcinomas and adenomas in germ-free rats, whereas in conven tional rat...

The monofunctional alkylating agent N-methyl-N-nitro-N-nitrosoguanidine (MNNG) is a widespread environmental carcinogen that causes DNA lesions, leading to cell death. However, MNNG can also trigger a cell-protective response by inducing the expression of DNA repair/transcription-related genes. We demonstrate that the urokinase-type plasminogen activator (uPA) gene product, a broad spectrum ext...

We report here in vivo gene transfer between cancer cells is associated with acquisition of high metastatic behavior. The 143B-GFP cell line with high metastatic potential and the MNNG/HOS-RFP cell line with low metastatic potential, both derived from the TE85 human osteosarcoma cell line, were either co-transplanted or transplanted alone in the tibia in nude mice. Upon mixed transplantation of...

Eb lymphoma cells were subjected to treatment in vitro with the alkylating mutagen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and then cloned by limiting dilution. When tested in vivo for tumorigenicity in groups of syngeneic DBA/2 mice, 6 from 18 clones were found to be strongly reduced (tum- phenotype). The other clones showed only moderate or no change in tumorigenicity compared to the untr...

We have used an in vivo-in vitro approach to investigate the cellular aspects of two-stage skin carcinogenesis. Female SENCAR mice initiated with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) were promoted twice weekly with 12-O-tetradecanoylphorbol-13-acetate (TPA). Epidermal cultures from untreated or TPA-treated mice had few focus-forming cells resistant to calcium-induced terminal differentia...

Mutagenesis induced by N-methyl-N-nitrosoguanidine (MNNG) and dimethylnitrosamine (DMN) in Salmonella TA 1530 was inhibited by ascorbate. Inhibition of MNNG-induced mutagenesis resulted from a reaction between ascorbate and MNNG that led to consumption of MNNG. The rate of this reaction was considerably enhanced by catalytic amounts of Cu(II) and Fe(III). No direct reaction between DMN and asco...

Embryos of gulf killifish Fundulus grandis were injected with N-methyl-N'-nitro-Nnitrosoguanidine (MNNG). Retention of carcinogen in the egg immediately after injection was highly variable. Hatching percentages of MNNG-injected and uninjected embryos were similar, but survival of MNNG-injected fish during the first week after hatching was less than half of the survival of controls. One of 3 MNN...