ascorbic-acid and nitrosobenzylmethylamine

A total of 391 gastric juice samples was collected from Ji Yuan and An Shi counties, high and medium risk areas of esophageal carcinoma in Henan province. NDMA, NDEA, NMBzA, NPip and unknown compounds were assayed in the fasting gastric juice. Among these nitrosamines, NMBzA, NPyr and NPip were specific in inducing esophageal cancer in animals. The amount of nitrosamines in the gastric juice collected from Ji Yuan county was higher than that from An Shi county. The exposure level of nitrosamines of subjects from these two localities were significantly different (P < 0.001). There was a positive relationship between the nitrosamines exposure level and esophageal cancer mortality rate. The amount of gastric N-nitrosamines from An Shi subjects as treated with vitamin C was reduced. It is evident that vitamin C can inhibit N-nitrosamine formation in the stomach, thereby, reducing the N-nitrosamines exposure level.

Topics: Adult; Aged; Ascorbic Acid; Dimethylnitrosamine; Esophageal Neoplasms; Esophagus; Female; Gastric Juice; Humans; Hyperplasia; Male; Middle Aged; N-Nitrosopyrrolidine; Nitrosamines; Precancerous Conditions

Carcinogenic and promoting effects of RRME as isolated from the pickled vegetables in Linxian County, a high incidence area of esophageal cancer, were studied in mice and rats. RRME alone did not cause tumor in the forestomach of mice and esophagus of rats. When the mice were intubated with a single dose of nitroso-sarcosine-ethylester (NSEE), the incidence of the forestomach carcinoma was only 9.5%. However, when the mice were given gastric doses of RRME after one single dose of NSEE, the incidence was increased to 41.0%. In rats, the tumor incidence was 5.3% in nitroso-methylbenzylamine (NMBzA) group, while in NMBzA kRME group, it was 20.7%. In rats intubated with NSEE for 7 times, no carcinoma appeared in esophageal epithelium; while followed by gastric doses of RRME, the incidence of esophagus carcinoma increased up to 63.2%. The experimental results show that RRME has distinct promoting effect on the process of cocarcinogenesis initiated by NSEE and NMBzA in the forestomach of mice and esophagus of rats, but without carcinogenic effect itself. Retinamide (RI) and massive dose of vitamin C showed an obviously inhibitory effect on promoting action of RRME in rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Antineoplastic Agents; Ascorbic Acid; Dimethylnitrosamine; Esophageal Neoplasms; Female; Mice; Nitroso Compounds; Rats; Rats, Inbred Strains; Stomach Neoplasms; Tretinoin