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

Folic acid is one of the 'younger' vitamins, yet it has attracted intensive study in the thirty years since the identification of pteroylglutamic acid and its polyglutamyl conjugates. The absorption and malabsorption of folates, natural, purified and synthetic, in disease has been studied more than any other vitamin and indeed folate absorption has become one clinical test of intestinal function. We know little about the release of folate from protein complexes, but we have learned, with the help of synthetic radiolabelled pteroylpolyglutamates that polyglutamyl folates are hydrolysed at or near the luminal border of the intestine and the released folate is efficiently absorbed. The rate limiting stage of folate absorption appears to be the transport of the monoglutamyl folate. In disease, and with drugs, folate malabsorption occurs primarily when monoglutamyl transport is depressed. The specific components of the folate transport system, listed in Table 4, are receiving increased attention. The mechanism of uptake is still a topic of controversy but a dual system including both a saturable and a diffusion component would explain most of the data. Reduction and methyl or formyl addition occur in the intestine but such metabolism is not obligatory for transport. The nature of folate binding within the cell and the function of specific folate binding proteins requires further study. At present we have little or no information about the mechanism of folate release from the epithelial cell to the circulation but this step also could influence the rate and specificity of overall process. The tools are now at hand to complete our understanding of the steps in folate absorption and metabolism. Such an understanding should facilitate the management of folate deficiency whenever it complicates gastrointestinal disease or drug therapy.
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PMID:Absorption and malabsorption of folates. 1 Jan 21

Hypolipidemias can be divided in primary, familial and hereditary forms and symptomatic forms which may accompany other diseases. The primary hypolipidemias (abetalipoproteinemia, hypobetalipoproteinemia and analphalipoproteinemia) are very rare. Severe hypolipidemia can be found in some peoples (e.g. the Masai). This article is chiefly devoted to secondary hypolipidemias such as those associated with malabsorption, malnutrition and maldigestion including protein-losing gastroenteropathy, with liver diseases, endocrine diseases (hyperthyroidism, hirsutism) and anemia. Finally, the hypolipidemias secondary to the formation of autoantibodies against HDL and LDL in M-gradient, carcinoma and rheumatoid arthritis are briefly reviewed.
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PMID:[Hypolipidemias]. 17 Jun 75

We studied five patients (two men and three women, age between 58 and 76 years) with clinical and electrophysiological signs of polyneuropathy. Routine neurological, hematological, and gastroenterological studies as well as procedures to test fat malabsorption were performed. Folate determinations were done using both radioactive and Lactobacillus casei methods. Two patients displayed the signs of subacute combined degeneration of the spinal cord with polyneuropathy, while three had only signs of neuropathy. All had low serum folate concentration, long-standing gastrointestinal disease, and deficient folate intake. The D-xylose absorption test gave values in all patients, while none displayed the classical malabsorption syndrome. The patients had substantial improvement or recovered (according to clinical and electrophysiological measurements) after periods ranging from 9 to 39 months of folate therapy. Such acquired folate-responsive polyneuropathy has two principal characteristics: mixed sensorimotor with mainly sensory deficits, and involvement of one or both of the lower extremities much more extensively than the upper extremities.
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PMID:Polyneuropathy and folate deficiency. 21 Jul 47

Dietary regimens in gastrointestinal disease can be divided into two categories: First, those of proven value include: (a) Disaccharide elimination for disaccharidase deficiency and exclusion of monosaccharides for sugar malabsorption; (b) gluten-free diet for celiac/sprue; (c) elimination of certain allergens because of food allergies; (d) protein restriction for portal systemic encephalopathy; (e) low-carbohydrate diet for dumping syndrome; (f) low-fiber diet for diarrheal syndromes; and (g) low-fat diet for steatorrhea. Second, controversial diets include a bland diet for acid-peptic disorders, a high-fiber diet for colonic disorders, and a low-fat diet for gallbladder disease. It is important to separate facts from fancy in the dietary management of patients with gastrointestinal disease and base the recommendations for a particular diet on available objective evidence, not on traditional or fashionable trends.
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PMID:Diet therapy in gastrointestinal disease: a commentary. 47 89

Oral triglyceride (TG) loading tests were performed in four groups of children: normal controls, patients with chronic nonspecific diarrhoea (CND), biopsy-proved mucosal pathology (MP), and disturbed intraluminal fat malabsorption (IFM). The rise of plasma TG levels greater than or equal to 55 mg/100 ml (greater than or equal to 0.6 mmol/l) can discriminate between patients with gastrointestinal disease and normal controls or patients with functional disturbances. The postmeal plasma TG rise correlates well with the coefficient of fat absorption (CFA) in normal subjects, patients with CND, and patients with IFM, but not in patients with MP who showed a disproportionally low plasma TG rise compared with their CFA. This test can serve as a useful tool in diagnosis and clinical evaluation for children with gastrointestinal disorders.
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PMID:Oral fat loading test: a reliable procedure for the study of fat malabsorption in children. 50 99

143 patients (70 patients with Crohn's disease, 11 with ulcerative colitis, 40 with an intestinal by-pass operation, 9 with non-tropical sprue, 10 with short bowel syndrome, and 3 with other gastrointestinal disease) were studied during a metabolic regime including a fixed oral supply of 70 g fat, 800 mg calcium, and 200 mg oxalate. Faecal fat, 47Ca-absorption, 14C-oxalate absorption, and renal oxalate excretion were measured, and in the majority of patients a 14C-glyco-cholic acid breath test was also performed. 14Ca-absorption was practically identical (r = 0.92), whether determined by whole-body counting or from the accumulation of absorbed 47Ca in the skeleton of the underarm. 14C-oxalate absorption and renal oxalate excretion agreed well (r = 0.85). Steatorrhoea correlated weakly with renal oxalate excretion (r = 0.63, p less than 0.001), whereas no correlation was present between faecal fat and calcium absorption or between oxalate and calcium absorption under the constant conditions prevailing during the study. It is recommended that a "trifixed" regime with absorption studies of fat, calcium, and oxalate be undertaken previous to therapy that aims at a reduction of steatorrhoea or hyperoxaluria or an improvement of calcium absorption in chronic malabsorption syndromes, not least because therapy of these categories of patients most often continues for years.
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PMID:Standardized ("trifixed") diet in the study of chronic malabsorption syndromes. 67 51

The time of breath hydrogen appearance (T) after oral lactulose was determined in 98 patients in London who had been to the tropics. Fifty-six controls from three different ethnic groups had no evidence of gastrointestinal disease; 23 had tropical malabsorption, which was severe in 10; and 19 had chronic diarrhoea without malabsorption. Mean T was significantly delayed in patients with tropical malabsorption compared with controls, indicating that their mouth-caecum transit rate was abnormally slow. In six patients with tropical malabsorption who were reinvestigated after treatment a fall in the value for T seemed to parallel clinical improvement. Three patients with diarrhoea due to chronic colonic disease had delayed T. Patients with tropical malabsorption have bacterial colonisation of the small intestine, which is important in the pathogenesis of the disease. Bacterial overgrowth, which sometimes occurs after infective diarrhoea in the tropics and gives rise to tropical sprue, is a result of stasis.
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PMID:Delayed small-intestinal transit in tropical malabsorption. 67 84

The importance of the distal small intestine and the ileocecal region for the regulation of gastrointestinal functions in humans has not been investigated in depth until recently. A regulatory role is postulated because even in healthy subjects, undigested nutrients pass across the ileocecal junction after most meals (physiologic malabsorption). Nutrient exposure of the ileocecal region causes slowing of gastric emptying and small intestinal transit, and decrease in small intestinal motor activity; under certain experimental conditions, ileal nutrients induce conversion of intestinal motility from digestive to interdigestive patterns. In addition, the secretory activity of the proximal gastrointestinal tract is inhibited by the ileocecal region. Inhibition of gastric secretion and exocrine pancreatic secretion are well established responses to ileal nutrient exposure; inhibition of bile secretion likely occurs, but is not proven. The intermediary mechanisms of these effects have not been clarified; the most likely candidates include endorphins, peptide YY (PYY), and glucagon-like-peptide-1 (GLP-1). Overall, the available data support the concept that the ileocecal region participates in the physiologic control of gastrointestinal motor and secretory functions. Whether disturbances of these regulatory mechanisms participate in the pathophysiology of gastrointestinal disease has not been investigated.
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PMID:[Regulation of gastrointestinal functions by the ileocecal area]. 148 55

A case of hypobetalipoproteinemia is described; a 16-year-old girl had been suffering for nearly 2 years from diffuse abdominal pain. The only clinical features were liver steatosis, slightly increased amino transferases and an incipient polyneuropathy. No sign of malabsorption or gastrointestinal disease was found. She had extremely low levels of cholesterol and triacylglycerol in her serum, slightly decreased serum phospholipids and normal HDL-cholesterol levels. Apolipoprotein B-100 was approx. 8% of normal, whereas B-48 was present at essentially normal levels. Electron microscopy of lipoprotein particles showed normal morphology of LDL. Examination of close relatives showed no abnormalities. Southern blots revealed no major deletions or rearrangements at the genomic level. Although rare, a- and hypobetalipoproteinemia should be considered as possible etiologies in patients with unexplained steatosis in the liver.
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PMID:Liver steatosis in hypobetalipoproteinemia. A case report. 191 73

The 14C-triolein breath test, a recognised index of fat absorption, and the p-aminobenzoic acid (PABA) test, a 'tubeless' test of exocrine pancreatic function, have both been widely used in the diagnosis of malabsorption and exocrine pancreatic insufficiency. This study evaluates the potential of a combination of both tests in the investigation of fat absorption and exocrine pancreatic function. Combination of the tests has become technically feasible because of the introduction of high pressure liquid chromatography as the preferred method of analysis for PABA, and use of p-aminosalicylic acid (PAS) as the marker for PABA absorption and metabolism. We studied 25 healthy subjects, 11 patients with exocrine pancreatic disease and 12 patients with gastrointestinal disease. The combined test identified subjects with reduced fat absorption and distinguished subjects with exocrine pancreatic insufficiency from those with an intestinal cause of fat malabsorption. The test could be completed in 7 h and had high patient acceptability. These findings suggest that the combined 14C-triolein breath test and PABA test can be used as a non-invasive, 1-day investigation of fat absorption and exocrine pancreatic function.
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PMID:Combined single day 14C-triolein breath test and PABA test in the diagnosis of malabsorption. 210 21


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