Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0847097 (acidity)
 15,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gastric metaplasia in the duodenum (GMD) is characterized by transdifferentiation of intestinal epithelial cells into gastric foveolar cells within the duodenal mucosa. GMD is often associated with duodenal ulceration. Higher duodenal acidity due to increased gastric acid output into the duodenum has been implicated in the development of GMD. Intestinal development and homeostasis are controlled by the homeobox transcription factor Cdx2, which is considered to be the master regulator of intestinal differentiation. Using immunohistochemistry, the present study shows that GMD is associated with loss of expression of Cdx2 and its target gene product sucrase-isomaltase. Quantitative RT-PCR experiments using the intestinal cell line Caco2 revealed that Cdx2 and sucrase-isomaltase were down-regulated and gastric mucins MUC5AC and MUC6 were up-regulated under acidic culture conditions. Thus, it is suggested that increased acid exposure leads to GMD by impairing the transcription of Cdx2 and subsequently that of its intestine-specific target genes.
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PMID:Evidence for acid-induced loss of Cdx2 expression in duodenal gastric metaplasia. 1525 92

Ranitidine is an antagonist of histamine-2 (H(2)) receptor. It is employed to treat peptic ulcer and other conditions in which gastric acidity must be reduced. Sucrase is a hydrolytic enzyme that catalyzes the breakdown of sucrose to its monomer content. A liquid of yeast sucrase was developed for treatment of congenital sucrase-isomaltase deficiency (CSID) in human. In this study, the effect of ranitidine on yeast sucrase activity was investigated. Our results showed that ranitidine binds to sucrase and inhibits the enzyme in a noncompetitive manner. The K(i) and IC(50) values were measured to be about 2.3 and 2.2 mM, respectively. Fluorescence measurement showed conformational changes after binding of ranitidine to the enzyme. The fluorescence spectra showed that ranitidine could bind to both free enzyme and enzyme-substrate complex, which was accompanied with reduction of emission intensity and red shift production.
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PMID:Ranitidine induces inhibition and structural changes in sucrase. 2185 Dec 10