methylnitronitrosoguanidine and Bile-Reflux

Experimental studies were performed to investigate the role, if any, of bile reflux in cancer development in the stomach. A 20% solution of human bile juice and 50 micrograms/ml of the known carcinogenic MNNG were given perorally and heterochronically to male Wistar rat, and the incidence of carcinoma in the gastric gland of the rat was studied. The animals were divided into 4 groups: Group I, to which only MNNG was given. Group II, to which human bile juice and then MNNG were administered. Group III, to which MNNG and then human bile juice were administered. And Group IV, to which only human bile juice was given. The incidence of cancer was 37.5% (3/8) in Group II, 25% (2/8) in Group III, and 0% in Group I (0/12) and IV (0/12). The gastric gland mucosa was histologically examined at various times and also by microautoradiography using 3H-TdR. The results suggested that a reverse flow of bile juice to the human remnant stomach may induce an increase in proliferative cells in the lacunar epithelia of the stomach mucosa and that a predisposed site would then be available for cancer development.

Topics: Animals; Bile; Bile Reflux; Gastrectomy; Gastric Mucosa; Humans; Male; Methylnitronitrosoguanidine; Rats; Rats, Inbred Strains; Stomach Neoplasms

An experimental study was performed using an organ culture method to evaluate the effect of a duodenal juice reflux on the development of cancer in the residual stomach. The following results were as follows. An intracellular DNA levels to combine with carcinogenic agents was significantly increased in the mucosa of the residual stomach compared to the parietal mucosa in the whole stomach (control group). In the human gastric mucosa exposed to the bile acid, the intracellular DNA level to combined with carcinogenic agents was increased, and thus the effect of the bile acid as a surfactant on the experimental development of gastric cancer was suggested. An atrophic change was main feature of the residual stomach. Autoradiographic findings revealed that the proliferative zone was extended and a number of immature cells appeared which became to be target cells. Therefore, the residual stomach might provide a situation where the cancer would easily develop.

Topics: Bile Acids and Salts; Bile Reflux; Biliary Tract Diseases; Cocarcinogenesis; DNA; Duodenum; Gastric Mucosa; Humans; Intestinal Secretions; Methylnitronitrosoguanidine; Organ Culture Techniques; Stomach Neoplasms

A gastroenterostomy without entero-anastomosis in rats favours the development of adenomatous epithelial lesions at the gastroenteral borderline in dependence of exposition to MNNG. The extent of such changes in the mucosa could be modified by vagotomy, pyloroplasty, or the prevention of duodenogastric reflux (Roux-en-Y method), whereby vagotomy has an enhancing effect on proliferation. A comparison of the mucosal changes at the gastroenteral anastomosis indicates that a multitude of factors causes environmental changes at the gastroenteral borderline, stimulating epithelial proliferation to the point of cancer formation. Thus, it is not possible to accuse any single factor such as intestinal reflux, carcinogens or different surgical techniques as the sole culprit in carcinogenesis.

Topics: Animals; Bile Reflux; Epithelium; Methylnitronitrosoguanidine; Neoplasms, Experimental; Postoperative Complications; Precancerous Conditions; Rats; Stomach; Stomach Neoplasms; Vagotomy