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Query: UMLS:C0024623 (gastric cancer)
 36,219 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Experimental carcinomas in the glandular stomach of rats were induced by oral administration of MNNG (M-methyl-N'-nitro-N-nitrosoguanidin) for 35 weeks or ENNG (N-ethyl-N'-nitro-N-nitrosoguanidin) for 20 weeks. Rats were killed at different times after beginning of carcinogen treatment and tissue specimens were prepared for histologic investigation. Particular interest was placed on the development of tumors and on pathological findings possibly contributing to early diagnosis of stomach cancer. During the development of tumors, several dysplastic reactions were observed in the antral mucosa. They could be classified into 4 groups: One was regenerative hyperplasia (1) that meant irregular glandular proliferations without cell atypism at the margin of erosions and ulcers. This lesion was mainly found 1-9 weeks after administration of MNNG. In glandular hyperplasia (2) either crypts or glands were extended and mucosal layers were thickened. No signs of cell atypism were observed. This lesion was mainly found 12-17 weeks after administration of MNNG. Dysplasia (3) was combined with considerable structural modifications and cellular atypism. However, this lesion was limited to the mucosal layer. Neoplastic changes (4) were characterized by marked cellular atypism and extension to tunica submucosa and tunica serosa. Some tumors showed the histological patterns of benign tumors, but most of them were adenocarcinomas. In some cases metastases into pancreas, liver and lymph nodes and in one case into the 12th rib were observed. No particular enzyme patterns were found by histochemistry.
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PMID:Development of tumors in the glandular stomach of rats after oral administration of carcinogens. I. Histological findings. 13 28

Using advanced gastric adenocarcinoma and carcinoid as human material and gastric adenocarcinoma in rats induced by MNNG and in mice by localized X-irradiation of the stomach as experimental material, a pathological study was made on the relationship of gastric endocrine cells to gastric cancer. The results of the present study suggest that most of the endocrine cells in the cancer tissue are derived from the differentiation of cancer cells. Therefore, the following three may be given as the aformentioned relationship, that is, 1) carcinoid of endocrine cell origin, 2) endocrine cell carcinoma showing undifferentiated adenocarcinoma, and 3) endocrine cell cloning developed from the differentiation of cancer cell of adenocarcinoma. There is the possibility that most of 2) are of 3) origin and thus 2) and 3) should be discriminated from 1), having a functioning tumor in rare cases. The significance of reactive hyperplasia of endocrine cells in the non-metaplastic mucosa of the stomach around cancer and atypical epithelium is not yet determined, but that of EC cell seems at least to be related with the development of intestinal metaplasia in the gastric mucosa.
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PMID:The relationship of gastrointestinal endocrine cells to gastric epithelial changes with special reference to gastric cancer. 17 Jul 85

In order to predict the chemopreventive activity of garlic on gastric cancer, the effect of diallyl sulfide (DAS), a natural extract of the garlic, on MNNG-induced nuclear aberration (NA) and ornithine decarboxylase (ODC) activity in Wistar rat glandular stomach mucosa was studied. The results showed that NA and ODC activity were positively correlated to MNNG dose given 24 and 6 hr after oral intubation with MNNG. Oral or parenteral pretreatment with DAS significantly and dose-dependently inhibited MNNG-induced NA and ODC. These data suggest that DAS has the potential to inhibit MNNG-induced gastric cancer, supporting the epidemiological evidence of the chemopreventive effect of garlic on gastric cancer.
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PMID:[Protective effect of diallyl sulfide, a natural extract of garlic, on MNNG-induced damage of rat glandular stomach mucosa]. 207 38

MNNG-induced experimental gastric cancer developed in the pyloric glandular region. Many of the tumors produced were well or moderately differentiated adenocarcinomas of elevated type. According to the degree of depth invasion, a majority of the tumors were classified as early-stage lesions invading within submucosal layer. There were two poorly differentiated lesions, which were both recognized as serosal neoplastic involvements. The tumors were positively stained by toluidine blue (pH 4.1) to indicate the presence of stroma. The Brdu-LI determined for gastric mucosal epithelial cells was significantly higher in the MNNG-treated group than in the untreated control group. However, the LI for cancer tissue in the MNNG-treated group did not significantly differ from that for gastric mucosa in the same group.
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PMID:Experimental gastric cancer induced by N-methyl-N'-nitro-N-nitrosoguanidine in rats. 238 39

In previous investigations using models for gastrointestinal cancer, the anticarcinogenic effects of diallyl sulfide (DAS), an organosulfur compound present in garlic, was established. In this study, we conducted experiments to determine whether DAS modulates two biomarkers, nuclear aberrations (NA) and ornithine decarboxylase (ODC) activity, in the glandular stomach mucosa of the Wistar rat. N-methyl-N'-nitro-N-nitrosoguanidine (MN-NG) induced dose-related NA and ODC activity in the glandular stomach 24 h and 6 h, respectively, after oral intubation with the carcinogen. Either oral or parenteral pretreatment with DAS significantly reduced the MNNG induction of NA or ODC. Furthermore, the suppressions were observed to be dose dependent. These data suggest that DAS may potentially inhibit MNNG-induced gastric cancer. In view of recent epidemiologic evidence linking reduced risk for gastric cancer with increased consumption of allium vegetables, it is clear that DAS has pluripotent effects as an anticarcinogen, although studies addressing a mechanism of action have yet to be reported.
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PMID:Effect of diallyl sulfide on MNNG-induced nuclear aberrations and ornithine decarboxylase activity in the glandular stomach mucosa of the Wistar rat. 263 29

Changes have been studied in human and rat pepsinogen phenotypes induced by N'-methyl-N'nitro-N-nitrosoguanidine (MMNG) in in vitro rat experiments and in vivo cultures of human and rat isolated gastric chief cells. In vivo the fastest migrating electrophoretic band decreased or disappeared as early as 3 weeks after the start of MNNG treatment. The changes, observed in 17 of 32 rats receiving MNNG, were permanent and consistently associated with pronounced histopathologic changes seen 10 months later (17 of 17). Comparable phenotypic changes were observed after 7 days only in MNNG-treated rat chief cell cultures. In human chief cell cultures a decrease of the Pg3 band, which is consistent with the "carcinogenic" phenotype, was observed in two of six preparations treated with MNNG. This early preceding change in phenotype preceding tumor formation may be useful as a diagnostic tool for the onset of gastric cancer.
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PMID:Changes in rat and human pepsinogen phenotypes induced by N'-methyl-N'nitro-N-nitrosoguanidine. 316 8

In an attempt to elucidate histogenesis of stomach cancer, quantitative analysis and measurement of DNA contents of various atypical lesions were sequentially made in the process of gastric carcinogenesis of Wistar strain of rats. Along with this, the effect of vagotomy on the development of atypical or neoplastic lesions were studied. A variety of focal lesions in the glandular stomach were seen in the middle or 4 and 12 weeks after the oral administration of N-methyl-N'-nitrosoguanidine (MNNG, 83 mg/l in drinking water) for 25 weeks. Both upward and downward growth was found in the intramucosal atypical lesions as well as frank carcinoma; the former lesions were histologically classified into 3 (Type I--Type III). On the basis of DNA distribution pattern, Type III lesions were considered to be intramucosal carcinoma and Type II to include precancerous state in some instances. In a group of rats vagotomized 1 week prior to the start of MNNG administration, there were significantly more lesions than in a group of MNNG alone. In contrast to the latter group which developed lesions in an uniform distribution pattern along the lesser curvature in the pyloric region, lesions in the former were characterized by random distribution pattern.
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PMID:[Study of the histogenesis and effect of vagotomy during gastric carcinogenesis by N-methyl-N'-nitro-N-nitrosoguanidine in rats--with special reference to atypical lesions]. 371 98

In study I, 48 ACI and Fisher inbred rats were given MNNG 100 micrograms/ml, with or without 1 per cent or 3 per cent red pepper diet; in study II, 164 Sprague-Dawley rats given MNNG 100 micrograms/ml, with or without 5 per cent or 10 per cent NaCl; in study III, 181 Wistar rats given MNNG 83 micrograms/ml with or without maejoo 10 gm per cent/diet; in study IV, 78 Wistar rats given MNNG 83 micrograms/ml with or without ginseng extract 150 micrograms/ml; in study V, 120 Wistar rats given MNNG 83 micrograms/ml with or without retinyl palmitate 150,000 IU/kg. Except for study II (28 weeks), all rats were fed the diets for 37 weeks and were examined at 38 weeks or 40 weeks. In study I, tumor incidence in rats fed a red pepper diet and MNNG solution were 57 per cent (ACI rats, 1 per cent red pepper) and 63 per cent (Fisher rats, 1 per cent or 3 per cent red pepper) which were higher than control group (44 per cent, 43 per cent); in study II, gastric cancer, 61.9 per cent (10 per cent NaCl-MNNG), 27.3 per cent (control); in study III, gastric cancer, 14.8 per cent (maejoo-MNNG), 24 per cent (control); in study IV, malignant tumor of gastroduodenum, 3.4 per cent (ginseng-MNNG), 32.1 per cent (control); in study V, forestomach papilloma, 10.7 per cent (retinoid-MNNG), 29.4 per cent (control), and cancer in duodenum and small intestine, 50.0 per cent (retinoid-MNNG), 17.6 per cent (control). Thus, gastric carcinogenesis was enhanced by red pepper and a high salt diet, was inhibited by a maejoo and ginseng diet and was not effected by vitamin A.
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PMID:Co-carcinogenic effects of several Korean foods on gastric cancer induced by N-methyl-N'-nitro-N-nitrosoguanidine in rats. 383 96

Electron microscopic examination of the MNNG-induced gastric cancer revealed cytodifferentiation processes in it. Transformation of gastric epithelium under the effect of MNNG at the submicroscopic and cell levels is investigated. The model is shown to be adequate to human gastric cancer.
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PMID:[Electron microscopy study of experimental stomach cancer]. 400 46

The effect of vaccinia virus on MNNG-induced gastric cancer in rats was studied. Subcutaneous inoculation of the highly attenuated vaccinia virus AS strain at intervals of 3 days from the beginning of the experiment showed prominent antitumor activity not only against adenocarcinoma induced by MNNG in the glandular stomach but also against squamous cell carcinoma in the forestomach. Both UV-inactivated vaccinia virus and the DI strain of mammalian pathogenic vaccinia virus, from which the AS strain originated, showed no antitumor effect.
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PMID:The effect of attenuated vaccinia virus AS strain on N-methyl-N'-nitro-N-nitrosoguanidine-induced gastric cancer in rats. 682 35


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