The effect of intra-gastric acidity and flora on the concentration of N-nitroso compounds in the stomach
| Autor: | J P Idström, David Armstrong, C. Cederberg, André L. Blum, Francesco Viani, Hans H. Siegrist, Brigitte Pignatelli, Elena F. Verdu, Michael Fried |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Adult
Male medicine.medical_specialty Flora Gastric acidity Nitroso Compounds Atrophic gastritis Gastroenterology Bacterial colonization Reference Values Stomach Neoplasms Internal medicine medicine Humans Single-Blind Method Enzyme Inhibitors Gastric carcinogenesis Omeprazole Hepatology business.industry Achlorhydria Stomach digestive oral and skin physiology Hydrogen-Ion Concentration medicine.disease digestive system diseases medicine.anatomical_structure Biochemistry Carcinogens Female business medicine.drug |
| Zdroj: | European Journal of Gastroenterology & Hepatology. 12:165-173 |
| ISSN: | 0954-691X |
| DOI: | 10.1097/00042737-200012020-00006 |
| Popis: | Correa's hypothesis proposes that gastric carcinogenesis is due to atrophic gastritis and hypochlorhydria which permit gastric bacterial colonization, the reduction of dietary nitrates to nitrites and the formation of potentially carcinogenic N-nitroso compounds (NOCs).To test the hypothesis that omeprazole-induced hypochlorhydria is associated with increased intra-gastric concentrations of nitrate-reducing bacteria (NRB), nitrites and NOCs.Single-blind study in healthy volunteers.Fourteen healthy subjects (seven female, mean age 24 years), free of Helicobacter pylori infection, received a one-week course of placebo followed by a two-week course of omeprazole, 20 mg daily.Fasted gastric samples, aspirated using a sterile double-lumen nasogastric tube at the end of the 1 st week (placebo) and the 2nd and 3rd weeks (omeprazole), were cultured aerobically and anaerobically; gastric pH and intra-gastric concentrations of nitrates, nitrites and NOCs were also determined.After weeks 1, 2 and 3, the intra-gastric concentrations of nitrate-reducing bacteria exceeded 10(5) colony-forming units (c.f.u.)/ml in 3, 7 and 9 subjects, respectively (P0.05). A gastric pH greater than 4.0 was associated with increased NRB (P0.05); however, neither increased gastric pH nor increased NRB, alone or in combination, was associated with increased intra-gastric concentrations of nitrites or NOCs (P0.05).A two-week increase in gastric pH in healthy, H. pylori-negative subjects was associated with increased intra-gastric concentrations of nitrate-reducing bacteria but not of nitrites or N-nitroso compounds. These data suggest that reduced gastric acid secretion is not a necessary precursor to the formation of carcinogenic N-nitroso compounds and that other mechanisms should be invoked to explain gastric carcinogenesis. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|