Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038358 (gastric ulcer)
 5,179 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Diethyldithiocarbamate (DDC) was injected subcutaneously in the rat and the mechanism of gastric ulcer formation was investigated. DDC induced gastric ulcers in a dose-dependent manner. DDC significantly suppressed gastric mucosal copper-zinc superoxide dismutase (Cu, Zn-SOD) activity at 2 hr. However, manganese-superoxide dismutase (Mn-SOD) activity was not changed. Gastric mucosal blood flow (GMBF) decreased to 52% of the control level at 2 hr after administration of DDC and gradually increased to reach the control level by 7 hr. A Shay rat preparation (4 hr) was used to study gastric secretion. DDC (200, 400 and 800 mg/kg) inhibited acid secretion to about 80% of the control level. Histopathological examination of the gastric mucosa after administration of DDC revealed mucosal congestive findings from 1 hr to 3 hr. These data suggested that the mechanism of DDC-induced gastric ulcer formation may be attributable to a decreased level of GMBF and O2- production owing to decreased SOD activity.
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PMID:Mechanism of diethyldithiocarbamate-induced gastric ulcer formation in the rat. 215 49

The activity of enzymes of the antioxidant system and pO2 in the gastric mucosa (GM) was studied in patients with gastric ulcer. The various enzymes differed in activity. Along with low activity of superoxide dismutase (SOD), glutathione peroxidase (GP), and glutathione reductase (GR), both normal and increased values were encountered. In GM hypoxia the GP activity increased in the peri-ulcerous zone. There was no statistically significant increase of SOD activity and reduction of GR activity.
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PMID:[Enzyme activity of the gastric mucosal antioxidant system during hypoxia]. 229 63

The aims of our experiments were to clear up the possible correlations between the free radical mechanisms and the gastric cytoprotection of beta-carotene on HCl-induced gastric mucosal lesions. The beta-carotene was intragastrically given in doses of 1 and 10 mg/kg and 30 min. later 1 ml 0.6 N HCl was given to provoke the mucosal damage. After 1, 5, 15, 30 and 60 min. the animals were sacrificed. The number and severity of gastric mucosal lesions were calculated. The superoxide dismutase (SOD), glutathion peroxidase (GPX), catalase (CAT) activity and the malondialdehyde (MDA) and reduced glutathion (GSH) contents were determined from the gastric mucosa of rats. It was found that 1. beta-carotene was able to reduce the number and severity of ulcers only after 30 min.; 2. the CAT activity was decreased at 60 min. by carotene; 3. the GPX activity became dissimilar in the different groups after 15 min; 4. the changes of GSH were found to be similar ones; 5. the SOD activity was lower during the cyto-protection; 6. the MDA level remained practically unchanged. It has been concluded that 1. the free radicals are the consequences of the development of gastric ulcer and cytoprotection; 2. the scavenger character of beta-carotene is involved in its cytoprotective effect.
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PMID:The free radical mechanisms in beta-carotene induced gastric cytoprotection in HCl model. 259 22

The mucosal superoxide dismutase (SOD) activities were serially examined on the acute gastric mucosal lesion (AGML) induced by water-immersion restraint stress to rats for six hours. The mucosal SOD activities gradually increased in proportion to the time up to 3 hours after the restraint stress. But it decreased 6 hours after when severe damage had been established in the mucosa. On the other hand, the mucosal SOD activities of the margins of human gastric ulcer showed to be higher on the healing stage than on the active stage. And the SOD activities of the intractable ulcer were lower than those of the curable ulcer. These results indicate that the mucosal SOD may play some important roles both on the protecting process information of AGML and on the healing process in gastric ulcer.
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PMID:[Changes in mucosal superoxide dismutase activities of gastric lesions]. 260 64

Diethyldithiocarbamate (DDC), an inhibitor of Cu,Zn-superoxide dismutase (SOD), at a dose of 500 mg/kg or aminotriazole (AT), an inhibitor of catalase, at a dose of 2,000 mg/kg reduced slightly gastric mucosal SOD activity, did not change gastric mucosal blood flow (GMBF), and did not cause gastric ulcers. However, when both DDC and AT were administered together, gastric mucosal SOD activity and GMBF remarkably decreased, and gastric ulcers appeared. Moreover, the administration of SOD attenuated gastric ulcer induced by DDC plus AT. These results suggested that SOD may play an important role in the gastric mucosal defense mechanisms against active oxygen species.
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PMID:Gastric mucosal protection and superoxide dismutase. 284 84

Effects of treatment with free radical scavengers in the healing process of acetic acid-induced gastric ulcer on the ulcer aggravation induced by indomethacin were investigated. Gastric ulcers were produced on the anterior wall of the stomach of male Sprague-Dawley rats by submucosal injection of 20% acetic acid. To investigate the role of oxygen radicals, rats with gastric ulcer were treated with scavengers for six weeks and then treated with indomethacin (1 mg/kg/day). While superoxide dismutase (10,000 units/kg/day) did not affect the ulcer area after indomethacin treatment, allopurinol (50 mg/kg/day) slightly inhibited the increase in ulcer area. Dimethyl sulfoxide (1% solution, ad libitum) produced a significant decrease in size of the ulcer after indomethacin treatment. Increased lipid peroxides in the gastric mucosa after indomethacin treatment decreased significantly in the rats of the dimethyl sulfoxide and allopurinol groups. These results indicate that lipid peroxidation mediated by oxygen radicals plays an important role in the mechanism of ulcer aggravation induced by indomethacin.
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PMID:Effects of free radical scavengers on indomethacin-induced aggravation of gastric ulcer in rats. 755 59

The pathogenesis of gastric mucosal injury is still poorly understood. Recent reports implicate redox active metals and reactive oxygen species as mediators of gastric damage induced by ethanol or non-steroidal anti-inflammatory drugs. Attempts were made therefore to prevent gastric injury using chelators and the antioxidant enzymes catalase and superoxide dismutase. These attempts, at best, would only detoxify extracellular reactive species, such as those produced by activated circulating granulocytes and macrophages. This study utilises another strategy by pre-emption of both intra and extracellular reactive species using radical-radical annihilation reactions and by detoxifying redox active transition metals. Nitroxide, stable free radicals were shown to enter mucous cells, protect against the ethanol induced damage, and prevent gastric lesions induced by aspirin, indomethacin, 25% NaCl, or 0.6 N HCl. These findings confirm that gastric mucosal damage from the above agents is mediated by free radicals and, moreover, introduce a prototypical agent within a potential new class of gastric ulcer preventing drugs.
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PMID:A novel antiulcerogenic stable radical prevents gastric mucosal lesions in rats. 795 22

We developed a new gastric ulcer model in which the ulcers are induced by the local injection of a ferrous iron and ascorbic acid (Fe/ASA) solution into the gastric wall. These ulcers resemble human gastric ulcers that penetrate the muscularis mucosa. The involvement of oxygen radical-mediated lipid peroxidation as the cause of these ulcers was investigated. With ferrous iron or ascorbic acid alone, gastric ulcers did not form, whereas penetrating ulcers were produced by the simultaneous injection of the Fe/ASA solution in a dose-dependent manner. Lipid peroxides significantly accumulated in the gastric mucosa from 1 to 24 h after the injection of the Fe/ASA solution. This increase in lipid peroxides preceded grossly evident gastric ulcer. Treatment with superoxide dismutase (SOD, recombinant human CuZnSOD) significantly reduced the size of the ulcers and inhibited the accumulation in lipid peroxides in the gastric mucosa, while treatment with apo-SOD or heat-inactivated SOD did not. These results suggest that lipid peroxidation mediated by oxygen radicals plays a crucial role in the pathogenesis of the gastric ulceration induced by the Fe/ASA solution.
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PMID:A new gastric ulcer model in rats produced by ferrous iron and ascorbic acid injection. 853 16

The production of superoxide radicals as a result of decreased Cu,Zn-superoxide dismutase activity is considered to be the most important factor in the pathogenesis of diethyldithiocarbamate (DDC)-induced gastric antral ulcers in rats. The aim of the present study was to identify possible sources of superoxide radicals and the role of platelet-activating factor (PAF) in DDC-induced ulcer formation. Groups of rats were pretreated with a drug or antiserum before DDC (800 mg/kg) administration. The size of the DDC-induced gastric antral ulcers was measured. Pretreatment with anti-rat polymorphonuclear leukocyte serum or CV-3988 (a specific antagonist of PAF) 20 mg/kg significantly reduced the size of DDC-induced gastric antral ulcers. The results confirmed that superoxide radicals play an important role in the pathogenesis of DDC-induced gastric ulcer in rats and suggested that NADPH (reduced nicotinamide-adenine dinucleotide phosphate) oxidase in PAF-activated polymorphonuclear leukocytes may be involved in the generation of these radicals.
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PMID:Sources of superoxide radicals involved in the pathogenesis of diethyldithiocarbamate-induced gastric antral ulcer in rats. 950 50

We investigated the role of xanthine oxidase-derived oxygen radicals in the development of endothelin-1-induced gastric ulcer. Mucosal lipid peroxidation showed a peak 24 h after injection, while gastric mucosal haemodynamics were fully restored 26 h after endothelin-1 injection. Allopurinol and oxypurinol, but not superoxide dismutase or catalase, protected the gastric mucosa 24 h after endothelin-1 injection. Oxypurinol antagonized both the vasoconstrictor effect of endothelin-1 and the decrease in gastric ATP. All treatments on the second day after endothelin-1 injection significantly reduced gastric mucosal damage. Xanthine oxidase-derived oxygen radicals contributed largely to the exacerbation but they did not mediate the onset of endothelin-1-induced gastric ulcer. Pretreatment with probucol (500 mg/kg, p.o.) also protected the gastric mucosa from endothelin-1-induced mucosal injury by its antioxidant activity. Oxypurinol was gastroprotective through its vasoactive and energy saving actions. The haemodynamic background of endothelin-1-induced gastric ulcer consists of long lasting ischaemia and subsequent "reperfusion" which may be responsible for the late burst of oxygen radicals.
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PMID:Oxygen radicals mediate the final exacerbation of endothelin-1-induced gastric ulcer in rat. 1117 71


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