Gastric bacteria, nitrate, nitrite and nitrosamines in patients with pernicious anaemia and in patients treated with cimetidine.

Patients with pernicious anaemia have a high risk of gastric cancer and we are investigating the role of N-nitroso compounds in their gastric carcinogenesis. We have carried out bacteriological studies and analyses of nitrite and N-nitroso compounds. Patients with duodenal or gastric ulcer are often treated with H2-receptor inhibitors such as cimetidine. This treatment induces hypochlorhydria similar to that in pernicious anaemia patients and it has been suggested that this might put these patients at risk of developing gastric cancer later. Analyses similar to those for p.a. patients have therefore been carried out in patients treated with cimetidine. We have set up an animal model of achlorhydria, using piglets, that will allow us to test in vivo the efficacy of compounds known to inhibit N-nitrosation in vitro. This is clearly necessary, in view of the growing size of the population now thought to be at risk.