BACKGROUND AND AIM: To clarify the roles of Helicobacter pylori cytotoxin in gastric atrophy, the cytotoxin positive rate and cytotoxin activity in Fukui and Okinawa, where the prevalence of atrophic gastritis and gastric cancer risk are quite different, were studied. MATERIALS: Seventy three strains from Fukui and 51 from Okinawa were examined. METHODS: The validation of atrophy was done by endoscopy, being confirmed with histology. The supernatant of liquid H pylori culture media was concentrated 20-fold, serially diluted, using doubling dilutions, and scored from 1 to 8. The semi-quantitated cytotoxin activity was expressed as the maximum dilution score yielding > 50% A431 cell vacuolation, being standardised with bacterial density. RESULTS: The cytotoxin activity of the strains from Fukui was highly diverse compared with that from Okinawa, although the cytotoxin positive rate was not different. In Fukui strains, the grade of atrophy and the cytotoxin activity were correlated (p < 0.05). In addition, the cytotoxin activity of the strains from all patients in Okinawa, most of whom showed closed-type/mild atrophy, was significantly lower than that of the strains from the patients with open-type/severe atrophy in Fukui (6.46 (5.53) v 9.76 (8.80), p < 0.05), (mean (SEM)). CONCLUSION: The difference in profile of the cytotoxin activity in the two areas was related to the difference in the prevalence of atrophic gastritis.
Histo-pathological appearances of DMH-induced colonic tumor in Wistar rats were sequentially observed upto the 35th week after the drug administration. In our series, 28 tumors were successfully induced in the colonic mucosa of 19 out of 64 rats treated with DMH, and they were histologically diagnosed as adenocarcinoma. However, there were differences in the histo-pathological findings of the carcinoma between the distal colon and the proximal colon in rats. That is, the slowly growing type of well differentiated adenocarcinoma was likely to originate from the proper mucosa in the distal colon, while in the proximal colon the rapidly growing type of tumor did from atypical glands in the lymphoid follicles. Therefore, it was suggested that histogenesis and growing processes of the carcinoma were differed in the distal colon from that in the proximal colon in rats. Second, epithelial mucosubstances and lectin-binding properties of these lesions were examined histochemically. There were differences in the lectin-binding patterns of UEA-I and PNA between carcinomas and/or atypical glands in the lymphoid follicle and normal background mucosa in rat colon. In the UEA-I staining, almost all tumors were positively stained except for one case, and in the well differentiated type a positive staining was discernible at the cell apex and secretory product in tumors, while in the undifferentiated type, it was seen at the cytoplasma and secretory product. From these histopathological and histochemical studies it may be concluded that these lectins is likely to be useful as tumor markers for the large bowel, and also effective for a diagnosis of minute carcinoma in the large bowel.
We investigated the production of vacuolating cytotoxin by Helicobacter pylori isolates from patients with peptic ulcer, atrophic gastritis or gastric carcinoma in order to examine the pathophysiological significance of vacuolating cytotoxin in these diseases.H. pylori was isolated from 18 patients (five with peptic ulcers, seven with atrophic gastritis and six with gastric carcinoma). Culture supernatants of H. pylori isolates, concentrated 20-fold, were serially diluted and then analyzed for cytotoxin activity semi-quantitatively using A431 cells as indicator cells. The relative activity of vacuolating cytotoxin was defined according to the maximum dilution.Cytotoxin production was observed in two out of five, six out of seven and six out of six isolates from peptic ulcer, atrophic gastritis and gastric carcinoma patients, respectively. The mean relative activity was calculated as 0.80, 2.71 and 2.50 inThese results suggest that vacuolating cytotoxin-producing H. pylori is strongly associated with both atrophic gastritis and gastric carcinoma.
