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Titolo:
Alterations in intragastric nitrite and vitamin C levels during acid inhibitory therapy
Autore:
Mowat, C; McColl, KEL;
Indirizzi:
Glasgow Royal Infirm, Dept Gastroenterol, Glasgow G4 0SF, Lanark, ScotlandGlasgow Royal Infirm Glasgow Lanark Scotland G4 0SF 0SF, Lanark, Scotland Univ Glasgow, Western Infirm, Dept Med & Therapeut, Glasgow G11 6NT, Lanark, Scotland Univ Glasgow Glasgow Lanark Scotland G11 6NT ow G11 6NT, Lanark, Scotland
Titolo Testata:
BEST PRACTICE & RESEARCH IN CLINICAL GASTROENTEROLOGY
fascicolo: 3, volume: 15, anno: 2001,
pagine: 523 - 537
SICI:
1521-6918(200106)15:3<523:AIINAV>2.0.ZU;2-0
Fonte:
ISI
Lingua:
ENG
Soggetto:
N-NITROSO COMPOUNDS; HELICOBACTER-PYLORI INFECTION; CHRONIC ATROPHIC GASTRITIS; ASCORBIC-ACID; DIETARY NITRATE; HUMAN SALIVA; CANCER RISK; BACTERIAL OVERGROWTH; HUMAN STOMACH; JUICE;
Keywords:
omeprazole; Helicobacter pylori; vitamin C; nitrite;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Citazioni:
56
Recensione:
Indirizzi per estratti:
Indirizzo: Mowat, C Glasgow Royal Infirm, Dept Gastroenterol, 84 Castle St, Glasgow G4 0SF, Lanark, Scotland Glasgow Royal Infirm 84 Castle St Glasgow Lanark Scotland G4 0SF
Citazione:
C. Mowat e K.E.L. McColl, "Alterations in intragastric nitrite and vitamin C levels during acid inhibitory therapy", BEST PR RES, 15(3), 2001, pp. 523-537

Abstract

Most nitrite entering the healthy acid-secreting stomach is derived from dietary nitrate. The latter is absorbed from the small intestine, 25% then being secreted by the salivary glands into the mouth. Buccal organisms subsequently convert 20% of this nitrate to nitrite. When this nitrite is swallowed, the ascorbic acid in the acidic gastric juice reduces it to nitric oxide, which is absorbed by the mucosa. In the process, the ascorbic acid is oxidized to dehydroascorbic acid. When the intragastric pH is elevated by powerful anti-secretory agents, this gastric chemistry is profoundly modified. At a neutral pH, the swallowed nitrite does not react with ascorbic acid but accumulates in the stomach. The level of nitrite in the gastric juice during treatment with anti-secretory medication is particularly high after anitrate-containing meal. Powerful anti-secretory medication also lowers the intragastric concentration of ascorbic acid and total vitamin C, probablybecause of the relative instability of the vitamin at a higher pH. These changes in the intragastric concentrations of nitrite and ascorbic acid are most marked in Helicobacter pylori-infected subjects on proton pump inhibitor therapy. It is recognized that an elevated nitrite-to-ascorbic acid ratio predisposes to the formation of potentially carcinogenic N-nitroso compounds. It is, however, unclear at present whether such compounds are formed within the human stomach.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 09/04/20 alle ore 12:15:46