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Query: UMLS:C0024523 (malabsorption)
 7,319 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous studies have provided evidence that an anaerobic bacterium, which degrades dietary oxalate to CO2 and formate, is present in colonic contents of a number of herbivorous species, laboratory rodents and humans. The present study examines the possibility that these bacteria degrade significant amounts of oxalate and can influence colonic oxalate absorption. Guinea pigs adapted to a diet containing 2% sodium oxalate or fed a normal diet were challenged with 67, 135, 170 or 200 mg of sodium oxalate containing 0.5 microCi of [14C]oxalate, which was injected into the cecum. Adapted animals excreted approximately 2% of the 14C in the urine, regardless of the dose, whereas unadapted animals excreted significantly higher amounts in the urine at the two lower doses and died at the two higher doses. Conversely, antibiotic treatment of adapted guinea pigs reduced the ability of their cecal flora to degrade oxalate, and a correspondingly greater percentage of an injected oxalate load was excreted in the urine. Oxalate degradation rates in cecal fluid were depressed by the secondary bile salt deoxycholate, and in vitro studies with pure isolates of guinea pig and human strains of oxalate degraders confirmed that these bacteria were highly sensitive to low concentrations of deoxycholate. Results indicate that these bacteria may be important in preventing excess absorption of oxalate and raise the possibility that the hyperoxaluria associated with bile salt malabsorption of ileal disease in part may be due to suppression of these bacteria by the bile salts.
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PMID:Intestinal oxalate-degrading bacteria reduce oxalate absorption and toxicity in guinea pigs. 337 43

Hyperoxaluria occurs with many gastrointestinal disorders complicated by malabsorption. This hyperoxaluria is known to be the result of increased colonic absorption of dietary oxalate. Proposed mechanisms for this effect include alterations in fecal fatty acids, alterations in fecal bile acids, and acidification of colonic pH. Using an animal model of lactulose-induced chronic colonic acidification, we examined the effect of pH on oxalate absorption in vivo. Rats were fed a diet containing 6.77 mg oxalate per day with and without lactulose. Cecal pH of the animals receiving lactulose was significantly lower than controls (4.90 +/- 0.42 vs 7.17 +/- 0.38; p less than 0.001). Urinary excretion of oxalate was significantly greater in animals receiving the lactulose diet than in controls (0.975 +/- 0.144 vs 0.844 +/- 0.172 mg oxalate per day; p less than 0.001). These results demonstrate that acidification of the colon results in a significant increase in urinary oxalate excretion. Thus, acidification of the colon may be an important factor in the pathogenesis of enteric hyperoxaluria.
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PMID:Role of cecal pH in intestinal oxalate absorption in the rat. 341 Nov 98

Oxalosis is a rare condition that may be either hereditary or acquired. It may be secondary to a number of primary causes, which include renal failure, oxalate poisoning, malabsorption syndromes, and in this case, ileojejunal bypass surgery. Systemic oxalate overload following such bypass surgery results from a defect in the enterohepatic circulation and from the loss of calcium and bile salts in the feces. The oxalate is then absorbed into the circulation, and the supersaturated solution precipitates in the systemic tissues. Reported cases of oral involvement are rare. This article presents a 2 1/2-year follow-up of such a patient and the resultant progressive and unrelenting nature of the disorder. As a result of our experience, we suggest early aggressive oral surgical management of the widespread oral lesions.
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PMID:Oral manifestations of oxalosis secondary to ileojejunal intestinal bypass. 342 99

Three tests of small intestinal function were performed at 3100 m and 4846 m to seek evidence of malabsorption of high altitude. Xylose tolerance did not change in 11 subjects but, in three who ascended to 5600 m, one-hour xylose levels were significantly lower. The results of an oxalate loading test did not suggest significant fat malabsorption. A direct fat absorption test using chylomicron levels after ingestion of 100 g fat showed significantly increased levels at high altitude. We conclude that there is no evidence of malabsorption up to 4846 m.
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PMID:Intestinal absorption at high altitude. 367 Dec 55

The regulatory functions of anions in colonic absorption of sodium are unknown. Absorption of sodium ions was assessed with chloride, butyrate, nitrite, sulphate and oxalate anions in segments of proximal/distal colon and in defunctioned colon. Efficiency of sodium absorption was related to availability of CO2 in mucosal cells: CO2 availability was enhanced (P less than 0.01) by sodium nitrite or diminished (P less than 0.01) in defunctioned colon. Sodium nitrite stimulated absorption of sodium in the distal colon where bicarbonate secretion predominated and n-butyrate stimulated absorption of sodium in the proximal colon where hydrogen ion secretion predominated. Sodium absorption was very significantly diminished (P less than 0.01) in defunctioned colon. Results indicate that sodium absorption in the colon is both a double anion exchange system as well as cation/anion co-transport. Anions act differently on sodium absorption along the length of the colon and prolonged lack of anions plays a part in sodium malabsorption of the defunctioned colon.
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PMID:Anion control of sodium absorption in the colon. 371 59

An investigation of variables important to calcium stone formation in urine indicated significantly increased daily excretion of calcium and oxalate and decreased excretion of ascorbate and citrate by recurrent calcium stone formers. In addition, urine volume, sodium, mucopolysaccharide, and protein were also significantly increased. We compared the uptake of citrate and ascorbate from the gut into the blood in normal controls and stone formers. These studies indicated significantly depressed absorption of both these hydroxycarboxylic acids in recurrent calcium stone formers. We also found that concurrent administration of citrate inhibited ascorbate absorption and increased urinary oxalate excretion after an ascorbate load in normal subjects and stone formers. These findings suggest a mechanism that explains hyperoxaluria in stone patients on the basis of a malabsorption of citrate, ascorbate, and possibly other hydroxycarboxylic acids.
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PMID:Chemical factors important to calcium nephrolithiasis: evidence for impaired hydroxycarboxylic acid absorption causing hyperoxaluria. 380 7

The pattern of oxalate uptake in various segments of the bowel has been studied after 80% small bowel resection and antiperistaltic colon interposition in Rhesus monkeys. The levels of urinary oxalate excretion were significantly raised in the immediate postoperative period, with progressive reduction at six and 12 months. None of the animals developed renal calculi. The possible benefit of the colon interposition after massive small bowel resection, in the prevention of hyperoxaluria and urolithiasis is suggested. Improvement in the fat malabsorption, formation of insoluble calcium oxalate in the bowel lumen, leading to reduced net intestinal absorption of oxalates is the possible mechanism.
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PMID:Absorption and urinary excretion of oxalates following massive small bowel resection and colon interposition in rhesus monkeys. 651 51

We have evaluated two procedures as screening tests for steatorrhoea: firstly, a simplified, two-day, oxalate-loading test and secondly the rate of urinary oxalate excretion following a single oral dose of oxalate. Following two-day oxalate loading there was almost complete overlap of the values for 24-h urinary oxalate between 15 apparently healthy volunteers and 10 patients with steatorrhoea. The rate of oxalate excretion following a single dose of oxalate was increased in one patient with Crohn's disease and ileal resection who had normal faecal fat excretion, but three patients with steatorrhoea due to other causes had normal rates of excretion. We conclude that these oxalate-loading tests are not a useful alternative to faecal fat estimation in patients with suspected malabsorption.
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PMID:Oxalate-loading tests to screen for steatorrhoea: an appraisal. 652 53

A case of oxalate lithiasis associated with Abetalipoproteinemia is reported. The excessive absorption of dietary oxalate in this patient with fat malabsorption occurs because unabsorbed fatty acids in the bowel lumen combine with calcium ions which would otherwise impair oxalate absorption by forming insoluble calcium oxalate crystals. The medical management include dietary fat restriction and supplements of the fat soluble vitamins A, E and K. The prognostic is poor particularly in the neurological and retinal component of this disease.
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PMID:[Oxalate lithiasis associated bith abetalipoproteinemia. Report of a case]. 667 Dec 65

Different screening tests for fat malabsorption were evaluated in patients with coeliac disease. The triolein breath test correlated well with results of faecal fat determination. Urinary excretion of oxalate with or without dietary oxalate loading was not correlated with faecal fat measurements. It is concluded that the triolein breath test is a useful procedure for the detection of fat malabsorption in patients with coeliac disease.
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PMID:Use of the triolein breath test for the demonstration of fat malabsorption in coeliac disease. 674 Feb 6


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