EDITORIAL SYNOPSIS The findings in this experimental study in cats resemble those previously noted in man with hypersecretion of acid by the stomach. The gastric type epithelium which develops in the duodenum probably arises from the necks of Brunner's glands.Intestinal metaplasia is a well-known occurrence in the human stomach. James (1963) has recently described the reverse anomaly, gastric epithelium in the duodenum. He examined biopsies taken at operation from the first part of the duodenum: patches of gastric epithelium were commonly found in patients with duodenal ulcer but were rare in patients with gastric ulcer or carcinoma. One patient with the Zollinger-Ellison syndrome had extensive gastric epithelium in the second part of the duodenum. Another patient who had an increased gastric acid secretion also had the change in the second part of the duodenum (James, 1963).These findings suggested a possible association between gastric epithelium in the duodenum and a high gastric acid secretion. This paper describes experiments to test whether the unusually high secretion of acid promoted by repeated injections of histamine could cause gastric epithelium to develop in the duodenal mucosa.
METHODSAdult cats, 12 females and eight males, were given intramuscular injections of histamine suspended in beeswax. In an attempt to find a suitable dosage of histamine, animals were given different doses for varying periods, the longest of which was four weeks. Some experiments had to be stopped because the animals became ill. Seven cats, which were not given histamine, served as controls. All the cats were killed by intrathoracic nembutal 24 hours after their last injection.Histamine was suspended in beeswax by the method described by Hay, Varco, Code, and Wangensteen (1942) and was diluted with mineral oil to give concentrations of 2, 10, and 20 mg./ml. The injection, which was given at 9.00 a.m. each day, could then be given without warming the preparation. By giving histamine suspended in beeswax to dogs with Heidenhain pouches it was shown that the effect of a single injection lasted for 24 to 36 hours.Immediately after death, the stomach and upper small intestine were removed, and a note was made of any mucosal ulceration or reddening. The entire duodenum with some antrum and jejunum was rolled up and fixed in 10% formol saline for 48 hours. The preparation was then cut longitudinally in two places, and sections were taken from the three pieces of tissue so obtained. They were stained by haematoxylin and eosin, and by periodic acid-Schiff reagent (P.A.S.). Suitably fixed tissue was not obtained from two female and two male cats.Three sections from each animal were examined for ulceration and stunting or flattening of the villi. Particular attention was paid to the nature of the surface epithelium and the presence of mucus-containing cells resembling gastric cells. The number of patches of gastric epithelium was counted but no attempt was made to count individual cells. The location of the patches was recorded. Becau...