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Background: Reactive types of oxygen play an important part also in carcinogenesis. Antioxidant enzymes are the primary defence against their damage. The objective of the present work was to glutathione peroxidase in the mucosa and polyps of the colon in subjects with colorectal adenoma and idiopathic proctocolitis., Methods and Results: The authors examined 18 controls, 43 patients with colorectal adenoma and 12 subjects with idiopathic proctocolitis. During endoscopy bioptic specimens of the mucosa and from polyps were taken for histological and enzymological examination: Cu/Zn superoxide dismutase, catalase, glutathione peroxidase. In subjects with colorectal adenoma a raised glutathione peroxidase activity was found in the colon and an elevated activity of superoxide dismutase in the adenoma. In patients with idiopathic proctocolitis in the stage of clinical remission in the mucosa a lower glutathione peroxidase activity was found but a high activity of all enzymes was recorded in the inflamed polyps., Conclusions: The cause of elevated activities of antioxidant enzymes in subjects with colorectal adenoma in the colonic mucosa and in adenomas is not known and calls for further studies. In patients with idiopathic proctocolitis the increased level of antioxidant enzymes in the mucosa is probably produced by a higher production of reactive oxygen types by activated leucocytes in the inflamed tissues.

Background: The primary defense against oxidation damage of tissues are anti-oxidant enzymes, e.g. superoxide dismutase, catalase and glutathione peroxidase. Some non-enzymatic substances have a significant anti-oxidant action (e.g. vitamin C, E, beta-carotene and others). The objective of the present work was to follow up the Cu/Zn superoxide dismutase activity, catalase and glutathione peroxidase (anti-oxidant enzymes of the gastric mucosa) in subjects with the risk of developing gastric cancer, e.g. those suffering from atrophic gastritis, hyperplastic polyps and gastric adenoma., Methods and Results: The authors examined 80 subjects (50 men and 30 women) aged 25 - 71 years. In all during endoscopic examination bioptic specimens of the mucosa were taken at standard sites of the gastric corpus and antrum for histological and enzymological examination. Enzymological examination: activity of Cu/Zn-superoxide dismutase (Randox Lab. Ltd. GB kit), catalase activity (modified method of Cavarocchia et al.) and glutathione peroxidase activity (method according to Paglia and Valentine). The Cu/Zn-superoxide dismutase activity was elevated in the group of patients with gastritis after gastrectomy (67%) and with gastric adenoma (35%), the catalase activity in patients with gastritis after gastrectomy (40%) and the glutathione peroxidase activity in patients with the diagnosis of gastritis after gastrectomy (185%), atrophic gastritis (46%) hyperplastic polyp (50%) and gastric adenoma (50%)., Conclusions: The increased activity of anti-oxidant enzymes was due to a higher concentration of the superoxide anion radical, hydrogen peroxide and organic peroxides (lipoperoxides); the source of active types of oxygen are phagocytic leucocytes in the chronically inflamed gastric mucosa.