Abstract
As a study for experimental demonstration of malignant change of gastric ulcer, a beeswax pellet containing 5 mg of 4-nitroquinoline-1-oxide and 2 mg of histamine phosphate was inserted in an artificial pouch of the glandular stomach of rats. Of the 14 rats autopsied after 153-336 days, 11 animals exhibited a chronic penetrating ulcer at the site of pellet application. In five of these 11 rats, some epithelial cells of the regenerating mucosa at the margin of the ulcer were quite atypical and infiltrated deeply into scar tissues of the ulcer base in a pattern suggestive of malignancy. In another rat, a tumor of the size of a finger tip occupied the margin and a part of the ulcer base, which was histologically mucoid adenocarcinoma. Although these results do not present a conclusive evidence of malignant change of gastric ulcer, this method of investigation is expected to provide a very effective means for further studies on the relationship between ulceration and carcinogenesis in the stomach.
