Male Sprgue-Dawley rats weighing about 200 g were used. For the induction of ulcers by laparotomy a catheter 1.7 mm in diameter was inserted directly into the intestinal lumen and hot water was flushed over the intestinal wall. As a result it was found that ulcers could be induced quite readily at any region of the intestine by this method, and the suitable temperature and amount of hot water proved to be 60°C-10 cc, 60°C-12 cc, 65°C-5 cc, and 80°C-3 cc. The time required for complete healing of ulcers paralleled with the depth of ulcers; namely, the ulcers invading up to muscle layers healed within a month, and those reaching up to the serosa or penetrating further took more than two months. There were, however, a few cases that did not heal within 6 postoperative months. Histological observations of these cases revealed regenerated villi and crypts to be irregular in the early stage but in the later stage smooth muscle cells reappeared in the stroma of the new villi and Paneth cells in the new crypts, showing a pattern of regenerated architecture bearing a close resemblance to the normal pattern. The body weight of experimental rats with ulcers in the upper portion or in the terminal region of the small intestine increased normally up to 6 monhts, except for the first few days when there was a slight loss of weight.
For the purpose of studying the healing process of ulcers, experimental ulcers were induced in the small intestine of rats, and one week later (acute stage) and 2 months afterward (chronic stage) 1μc/g body weight of3H-thymidine was injected into the peritoneal cavity of these and control rats for the autoradiographic analysis. One animal each from the acute, the chronic and the control groups was sacrificed at interval of one hour for 17 hours. The cell cycle of the epithelium of the small intestine was determined by calculating the percentage labeling of mitotic cells. Serial sections of the ulcer margin were prepared for reconstruction study of regenerating epithelium two hours after3H-thymidine injection. Then the proliferative capacity of smooth muscle cells of the ulcer margin and that of granulating tissues at the base of the ulcer were also studied two hours after the thymidineinjection. As a result it was found that the cell cycle of epithelium at the ulcer margin was significantly accelerated in the acute stage (GT=8.9 hr) and in the chronic stage (GT=9.0 hr) as compared with that in controls (GT=10.8 hr). These were mostly due to the shortening of G1 phase. However, it was demonstrated that the generation time of individual proliferating cells varied a great deal in the chronic stage. Study of the reconstruction model in the acute stage revealed hypertrophied and multilobulated crypts with poor thymidine intake in newly formed epithelium. On the other hand, in the chronic stage this histological feature became more prominent in association with marked thymidine intake up to the surface epithelium, and new crypts were generated from the surface epithelium and crypts at the ulcer margin themselves. Fairly many labeled nuclei of the smooth muscle cells at ulcer margin were found in the acute stage, but few in the chronic stage. A large number of labeled cells of granulating tissue at the base of the ulcer were observed in the acute stage, and a fairly large number in the chronic stage as well.
An investigation was undertaken on 436 patients following gastrectomy and approximately 30 per cent of them were proved to have milk intolerance of a varying degree. Such an intolerance was considered to be due to the fact that lactase activity in mucosa of the small intestine had been low before the surgery. In addition, it was found in a few cases that disaccharidase activity decreased after gastrectomy. The Lactose Tolerance Test and X-ray barium test were found to be ineffective, and it is considered that the only way to diagnose milk intolerance following gastrectomy is to measure lactase activity in the intestinal mucosa in relation to the patient's symptoms. It is therefore emphasized that lactase preparations are effective in treating milk intolerance following gastrectomy, and that the use of lactase preparations at the time of milk intake is recommended in order to prevent osteomalacia following such surgery.