Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024623 (gastric cancer)
 36,219 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have been investigating possible effects of sex hormones on the carcinogenesis of stomach cancer in Wistar rats that were given N-methyl-N'-nitro-N-nitrosoguanidine in drinking water (50 micrograms/ml) for 4 months. The incidences of stomach cancer in intact male, intact female, castrated male, and castrated female rats at Month 4 of the experiment were 5, 0, 0, and 0% respectively; and those at Month 8 were 40, 10, 0, and 0% respectively; indicating that the incidence in intact males was much higher than in the other groups. The difference in the incidence became more evident when the animals were sacrificed at Month 12 of the experiment (81, 0, 29, and 5%, respectively). Hypertrophy and dissociation of the lamina muscularis mucosae which are considered to occur in the carcinogenic process were observed only in the male rats at the earlier months, but not in female nor in castrated rats. In N-methyl-N'-nitro-N-nitrosoguanidine carcinogenesis, female and castrated rats had a lower incidence of gastric cancers with less change in the lamina muscularis mucosae than did the nontreated male rats. These findings, therefore, suggest that, in addition to the suppressive action of female hormones, male hormones facilitate carcinogenesis.
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PMID:Effect of sex hormones on carcinogenesis in the stomachs of rats. 713 22

Sequential studies were made on the histopathologic changes in the glandular stomach of rats induced by a weak carcinogen. N-propyl-N'-nitro-N-nitrosoguanidine (PNNG). Fiftyfour rats were given 100 micrograms/ml of PNNG in their drinking water for 44 weeks, and then normal tap water until the end of the experiment. Rats were killed at intervals between week 1 and week 88. No marked atrophy or ulceration of the mucosa was found between week 1 and the end of the experiment. Focal intestinal metaplasia was found in week 19 and its incidence increased during the experiment. Adenocarcinoma in situ with extreme cellular atypia was found in mucosa with a normal appearance in week 67. An adenocarcinoma invading the submucosa was found in week 69, and one invading the serosa in week 88. All these pathological lesions were found on the anal side of the pyloric region. No pathologic changes were found in the fundic region. The sequential changes of the mucosa of the glandular stomach induced by this weak gastric carcinogen, PNNG, were very different from those induced by the potent gastric carcinogen, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Gastric carcinoma induced by PNNG seems to be more similar to human gastric cancer than that induced by MNNG.
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PMID:Sequential studies on the histopathogenesis of gastric carcinoma in rats by a weak gastric carcinogen, N-propyl-N'-nitro-N-nitrosoguanidine. 721 80

Nitrosomethylurea (NMU) formation was measured radioactively in the stomach contents of rats fed 3H-methylurea and sodium nitrite, mostly in semi-synthetic diets. When methylurea and sodium nitrite were added to various diets, the NMU concentration, averaged over 1-4 hours after the food was presented, was 4.6 micrograms/kg stomach contents for low-protein, 2.7 for control semi-synthetic, 2.4 for high-fat, 1.26 for bran, 1.24 for high-protein and 0.54 for the commercial diet. With the low-protein diet, the amount of NMU after 1 hour was 36.6 micrograms, corresponding to 5.3% conversion of methylurea. The decrease in yield as protein content increased was attributed to buffering action and competition for nitrite by the protein, as well as to the effects of the latter on consistency. It may also be correlated with the observation that human gastric cancer is associated with high-starch low-protein diets. Nitrite in diet was more effective in producing NMU than the same nitrite concentration in drinking water, except with sodium nitrite concentrations less than or equal to 0.5 g/kg vehicle, where the position was reversed. Sodium ascorbate added to a semi-synthetic diet at a level of 2.9 g/kg inhibited NMU production by 50%.
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PMID:Dietary and other factors affecting nitrosomethylurea (NMU) formation in the rat stomach. 722 57

Occupational studies have shown that asbestos is a human carcinogen. Because many inhaled asbestos fibers deposited in the lung are cleared and swallowed, workers are also exposed through ingestion. Of the millions of current and former workers who have been heavily exposed to asbestos, one in ten will die from cancer of the gastrointestinal tract. A number on the order of 1 in 1,000 ingested asbestos fibers penetrate the digestive tract and ingested fibers have been recovered in such tissues as kidney, intestine, liver, and urine. One animal study showed tumor production related to ingestion of asbestos-containing material but, in general, the results of seven animal feeding studies have been inconclusive. A statistically significant relationship between male lung and stomach cancer and female peritoneal, gall bladder, and esophageal cancer and asbestos counts in drinking water was determined in one epidemiology study. Increased rates for male stomach and lung, and female pancreatic cancer related to asbestos in drinking water were reported in another study but possible occupational exposure made it difficult to draw conclusions. Data on excess gastrointestinal cancer among occupational groups has been used to estimate that drinking water containing 300,000 asbestos fibers per liter over a lifetime will result in one additional cancer among 100,000 people.
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PMID:The need to control asbestos fibers in potable water supply systems. 723 79

CD/CRJ rats were subjected to localized X-irradiation of the stomach and given N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in the drinking water. Rats given MNNG alone and non-treated rats were used as controls. Upon sacrifice at 15 months after the initial MNNG administration, intestinal metaplasia was observed; the histology was of complete type and the incidence was 100% in rats treated with X-rays and MNNG, whereas in rats treated with MNNG alone the intestinal metaplasia was of incomplete type and its incidence was 80%. However, the incidence of gastric cancer in rats treated with MNNG alone was 25%.
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PMID:Induction of intestinal metaplasia in the glandular stomach of rats by X-irradiation prior to oral administration of N-methyl-N'-nitro-N-nitrosoguanidine. 727 26

In a retrospective study of the relationship between reuse of water and hazards to health, the mortality experience from different causes, principally cancer, was examined for 29 boroughs and districts in the London area for the period 1968 to 1974. Information concerning the source of water supply to each borough was obtained both for the current situation, and historically back to 1926. Socioeconomic characteristics of the boroughs were extracted from 1971 census data. Differential mortality experiences for each sex were analysed using the standardised mortality ratio for ages 25 to 74. Most of the causes of death examined were associated with one or more of the socioeconomic characteristics of the boroughs. These socioeconomic characteristics accounted for the statistical associations between water reuse and mortality for each cause studied, except male stomach cancer, where a weak residual association remained. This association disappeared when variation in the size of boroughs was taken into account.
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PMID:The relationship between water quality and health in the London area. 728 71

The city Zabrze (Upper Silesian Region, Poland) was divided into districts differing in respect to drinking water stations. Geographic correlation between the stomach cancer incidence in native and immigrant populations and the quality of water used for drinking were investigated. It has been shown that in the districts where water of greater hardness has been used for drinking, the stomach cancer incidence was much lower than in other areas, especially in native male populations.
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PMID:A possible association between quality of drinking water and stomach cancer incidence among native and immigrant populations of a selected industrial city. 737 58

Mortality from stomach cancer was examined over the period 1958-75 on Workshop and 5 other nearby mining towns, and in 4 non-mining towns in Nottinghamshire. For each town, expected numbers of deaths at national rates were adjusted to allow for local/national differences in social-class distribution and number of miners, since mortality is known to be high nationally among miners and miners' wives, and to vary markedly with social class. After adjustment, the stomach-cancer Standardized Mortality Ratios (SMRs) for the aggregate of mining towns were 92 for men and 104 for women. For the non-mining towns equivalent SMRs were 91 and 86, and mortality was markedly low at ages under 65 for both sexes. Mortality in Workshop was not significantly raised, and appeared similar to that elsewhere in the mining towns. This result does not support the earlier finding by others that stomach-cancer mortality in the town was significantly raised, nor the accompanying suggestion of an association with the high nitrate content of the local drinking water via the action of nitrosamines.
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PMID:Stomach cancer mortality in Worksop and other Nottinghamshire mining towns. 738 34

The concentrations of nitrates in public drinking water in the Mediterranean coastal province of Valencia are not only the highest in Spain but also in the whole of Europe. Intensive agricultural practices involve a traditional and growing use of nitrogen fertilizers. This and the terrain--poorly consolidated and porous in areas--favors the accumulation of nitrates in underground aquifers, thereby perhaps accounting for this contamination. The possible conversion of nitrates to nitrites under certain conditions of gastric achlorhydria, followed by their transformation to nitrosamines--substances known to be carcinogenic in experimental models--has led to a number of epidemiological studies of the possible relationship between high nitrate levels in public drinking water and mortality due to different cancers. The aim of the present study was to analyze the relationship between different levels of exposure to nitrates in the drinking water of the 258 municipalities in the province of Valencia and mortality due to cancer of the stomach, bladder, prostate and colon in this population. The cancer mortality rate was found to rise with increasing exposure to nitrates in the case of gastric cancer in both sexes, and in prostate cancer. These same results were obtained on calculating relative risk for the different age groups associated with the consumption of drinking water containing different levels of nitrates.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Impact of nitrates in drinking water on cancer mortality in Valencia, Spain. 748 69

The effects of treatment in a hydrated autoclave (121 degrees C, 2 atm for 20 min), microwave oven (in water), and simple heating (60 degrees C overnight in distilled water or 90 degrees C for 10 min in ZnSO4) on the stainability of 56 antigens by commercially available antibodies in formalin-fixed paraffin-embedded tissue sections were evaluated. The detectability of nuclear antigens, glycoprotein, lymphocytic surface markers, and chromogranin A was significantly and reproducibly improved by these treatments, whereas the detectability of viral antigens and peptide hormones was attenuated or unchanged. This enhancement includes not only the distinctiveness of the positive staining, but also the number of positive cells, as revealed by comparing serial sections. Among these four heating procedures, microwave heating and autoclaving were more effective than the others on p53, c-erbB-2, and CA125, whereas simple heating was best for smooth-muscle actin (HHF35 and CGA7). Generally the effects of the heating procedures for these antigens were consistent among the cases, but the effects on GFAP varied with the case. The alterations we observed could significantly influence the interpretation of immunohistochemical staining of currently popular tumor markers such as p53 in terms of their prevalence (28% vs 64% in gastric cancer; 36% vs 82% in metastatic liver cancer) and other diagnostically important markers.
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PMID:Alteration of immunoreactivity by hydrated autoclaving, microwave treatment, and simple heating of paraffin-embedded tissue sections. 751 73


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