Evaluation of the nitrosamine hypothesis of gastric carcinogenesis in man.

Patients who had undergone a Billroth II gastrectomy (PG) or had pernicious anaemia (PA) and healthy matched control subjects (MC) participated in 24-h studies in which bacteria, nitrite and N-nitroso compounds (NOC) were measured in gastric juice and N-nitrosoproline (NPRO) in urine. Consistent with the nitrosamine hypothesis, intragastric levels of bacteria and nitrite were positively related to intragastric pH, but, contrary to the hypothesis, NOC in gastric juice and NPRO in urine were negatively related to intragastric pH.

Evaluation of the nitrosamine hypothesis of gastric carcinogenesis in precancerous conditions.

A 24 hour gastric aspiration study was carried out on nine Polya gastrectomy, eight pernicious anaemia, and nine matched control subjects. Intragastric pH, bacteria, nitrite, and N-nitroso compounds were assessed half hourly whilst ambulant and hourly when in bed. Both total and nitrate reducing bacterial counts were positively related to pH (chi 2 = 279.

Epidemic hypochlorhydria.

During a study of gastric secretion four out of six previously healthy subjects developed hypochlorhydria after a transient illness with nausea, vomiting, and abdominal pain. Mean basal and peak acid outputs were 0 and 2.3 mmol (84 mg)/h one month after the onset of illness and 1.

Intragastric N-nitrosation is unlikely to be responsible for gastric carcinoma developing after operations for duodenal ulcer.

Three groups of patients studied after operations which had cured their duodenal ulcer were compared with a control group (no operation, n = 8). The surgical procedures included: proximal gastric vagotomy (n = 7), truncal vagotomy and pyloroplasty (n = 7), truncal vagotomy and antrectomy (n = 8). Samples of gastric juice were aspirated half hourly or hourly over 24 hours for measurement of pH, counts of all identified bacteria, nitrite and total N-nitrosocompounds.

Intragastric acidity, bacteria, nitrite, and N-nitroso compounds before, during, and after cimetidine treatment.

Eight healthy subjects were studied half-hourly or hourly for 24 h periods before, during, and after cimetidine treatment. No significant differences in intragastric bacterial counts or bacterial species or in intragastric nitrite or N-nitroso-compound concentrations were found as a result of cimetidine treatment. Bacterial counts and nitrite concentrations tended to increase with pH, but N-nitroso-compound concentrations did not.