Abstract
Pathology and pathophysiology of gastric mucosal injuries were studied from the endoscopic point of view, and the following our results were presented. 1.Thermal injuries in canine gastric mucosa were studied. Marked atrophic gastritiswith pseudopyloric gland heterotopia was experimentally produced in dogs with theconsecutive administration by gastric intubation of 300ml of 58°C warm water for 175 to 457days. The results suggest that the thermal agent is one of the cause of atrophicgastritis. 2.The gastric ulcerogenesity of cinchophen(220mg/kg/5 × W)was evaluated in theferret. It was most severe at 3-4 days. Secretory studies revealed no change in acidconcentration and pepsin activity. Histopathologic study of 6 antral pouch ferrets demon-strated only mild acute inflammatory changes following cinchophen administration directly into the pouch and no antral changes following peroral administration. The results showgastric acid play an imoirtant role in cinchophen-induced ulcerogenesis. 3.To study the role of mucus bicarbonate barrier(MBB)in gastric mucosal cytoprotection, experimental chamber system was newly deviced. The thickness of mucus gellayers, grade of back diffusion of gastric acid, and potential difference were measured inthe rat gastric mucosa. Gastric mucus was secreted reactively to the various stimulantsincluding aspirin, ethanol(100%), 25%Nacl solution and PGE2 to maintain the MBBfunction. When stimulations were too strong, back diffusion of gastric acid occurred, followed by decrease in secrtion of gastric mucus as well as alkali, and, finally, resulted ingastric mucosal injuries. 4.The role of bile acid regurgitation was clinically studied with reference to thecarcinogenesis of remnant gastric mucosa. Mucosal biopsies were taken from the marginof the stomas of gastric pouch, and evaluated their histological atypicity based on thecriteria of Japanese Society of Gastric Cancer. The incidence of group III was significantlyhigh in specimens collected from stomal margins of Billroth-II anastomoses elapsed morethan 10 years compared to those from Billroth-I anastomoses(P<0.01), suggesting therelationship between bile acid regurgitation and carcinogenesis. In addition, cumulativehazard rate to mucosal atypicity was high in helicobacter pylori(HP)positive gastricmucosa, suggesting the contribution of HP in carcinogenesis of remnant stomach. 5.Role of nitric oxide(NO)on adaptive cytoprotection was studied with similarchamber system deviced for monitoring NO genertation, gastric mucosal blood flow(laser doppler probe)and gastric electromyogram. From our study, it was thought to be animportant factor that back diffusion of gastric acid into the mucosa induce the NOgeneration in the gastric mucosa, followed by the transient increase in the gastric mucosalblood flow, indicating the NO generation play an important role to maintain the gastric mucosal blood flow.
