Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024523 (malabsorption)
 7,319 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Reduction in acid secretion in atrophic gastritis allows bacterial colonization of the stomach, most extremely in achlorhydric patients with pernicious anaemia, in whom overgrowth may cause nitrate reduction and formation of potentially carcinogenic N-nitroso compounds. Subsequent bacterial contamination of the upper small intestine can induce mucosal damage and malabsorption. The situation is similar after gastrectomy. In achlorhydria and after gastrectomy, the risk of gastric cancer is increased. There is controversy as to the risks of long-term treatment with H2-receptor antagonists. Increase in nitrate-reducing bacteria, nitrite and N-nitrosamine have been observed in patients by some investigators but not in volunteers and patients by others. Bacterial concentrations after cimetidine are inversely related to pretreatment acid secretory capacity. Demonstration of increased mutagenicity of gastric juice after H2-receptor antagonists gives grounds for caution. Drastic acid reduction may in future be reserved for short-term and intermittent treatment and mild or moderate reduction for long-term treatment of peptic ulcer and ulcer prevention.
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PMID:Bacterial overgrowth as a consequence of reduced gastric acidity. 286 52

Intragastric bacterial colonization is well known in pernicious anaemia (PA), but its consequences have rarely been investigated. We have studied the clinical history, blood samples, and endoscopic biopsies from the stomach and duodenum of 80 patients with PA. In a random subgroup of 22 patients gastric juice was collected for aerobic culture and for estimation of nitrate, nitrate-reducing bacteria, nitrite, and N-nitrosamines; duodenal juice was studied in parallel in eight of these subjects. Gastric and duodenal juice had high bacterial counts; faecal organisms were found in 14 patients. The mean count of nitrate-reducing bacteria was significantly higher than in a control group of patients with peptic ulcer disease (p less than 0.001), as was the nitrite concentration (p less than 0.001). Thirty-three of the 80 patients had gastric dysplasias; 1 early gastric carcinoma was also found. Duodenitis was present in 39 out of 80 cases, in 6 associated with partial villous atrophy. A history of malabsorption and/or chronic intermittent diarrhoea was obtained significantly more often from patients with duodenitis. Four patients developed acute gastroenteritis shortly before or during the time of the study, two having a salmonella infection. Bacterial overgrowth in PA may be facilitated by altered immunological conditions, since low serum levels of IgA and IgG were found in this patient group.
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PMID:Pernicious anaemia, intragastric bacterial overgrowth, and possible consequences. 674 Feb 11

As part of a program to study the pathological effects of coccidia infections on growth, we have examined the relationship of plasma L-arginine (ARG) levels to infective doses of Eimeria acervulina and infection-associated changes in weight gain, plasma carotenoids, and plasma NO2- + NO3-. Chickens consuming a starter ration containing 1.68% ARG were infected with a range of doses of E. acervulina. At 6 d postinoculation (PI), weight gains were significantly reduced by infections with 5 x 10(5) and 1 x 10(6) oocysts per chick (OPC). Gross lesion scores of chickens infected with 5 x 10(4) through 1 x 10(6) OPC were significantly greater than scores of chicks infected with 1 x 10(3) OPC. Compared with levels from uninfected controls, plasma NO2- + NO3- concentrations were significantly increased by infection with 5 x 10(5) and 1 x 10(6) OPC, plasma concentrations of ARG were significantly decreased by infection with 5 x 10(4) through 1 x 10(6) OPC, and plasma carotenoids were significantly decreased by all infection doses. Plasma arginine was significantly correlated with plasma carotenoids (P > 0.0187), but not with infection dose or weight gain; plasma NO2- + NO3- was positively correlated (P > 0.0043) with infection dose and negatively correlated (P > 0.0158) with weight gain. Regression analysis of the measured variables indicated that the strongest relationship existed between plasma ARG and carotenoids. This finding suggests that in this infection model, reduction in plasma ARG is most likely associated with nutrient malabsorption that accompanies infection and is likely not significantly impacted by synthesis of nitric oxide that is associated with the immune response.
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PMID:Effect of Eimeria acervulina infections on plasma L-arginine. 1105 46

The proton-coupled folate transporter (PCFT) plays a key role in intestinal folate absorption, and loss-of-function mutations in the gene encoding this transporter are the molecular basis for hereditary folate malabsorption. Using a stable transfectant with high expression of PCFT, physiologic levels of bicarbonate produced potent and rapidly reversible inhibition of PCFT-mediated transport at neutral pH. Bisulfite and nitrite also inhibited PCFT function at neutral pH, whereas sulfate, nitrate, and phosphate had no impact at all. At weakly acidic pH (6.5), bisulfite and nitrite exhibited much stronger inhibition of PCFT-mediated transport, whereas sulfate and nitrate remained noninhibitory. Inhibition by bisulfite and nitrite at pH 6.5 was associated with a marked decrease in the influx Vmax and collapse of the transmembrane proton gradient attributed to the diffusion of the protonated forms into these cells. Monocarboxylates such as pyruvate and acetate also collapsed the pH gradient and were also inhibitory, whereas citrate and glycine neither altered the proton gradient nor inhibited PCFT-mediated transport. These observations add another dimension to the unfavorable pH environment for PCFT function in systemic tissues: the presence of high concentrations of bicarbonate.
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PMID:Inhibition of the proton-coupled folate transporter (PCFT-SLC46A1) by bicarbonate and other anions. 2360 45