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)

Intestinal permeability to probe molecules has been shown to correlate closely with the presence or absence of villous atrophy in a jejunal biopsy. The purpose of this study was to establish if there exist groups of patients with functional derangement of intestinal permeability but normal histopathology of the small bowel mucosa. In 135 patients a cellobiose/mannitol permeability test was performed at the same time as jejunal biopsy. Diagnosis included coeliac disease, Crohn's disease, irritable bowel syndrome, idiopathic diarrhoea, self diagnosed food allergy, atopic eczema and postinfectious malabsorption. The value of the cellobiose/mannitol test in identifying patients with abnormal jejunal biopsy histopathology was confirmed. The permeability test was abnormal in all 28 patients with partial or subtotal villous atrophy, and also in all 10 in whom there was a high intraepithelial lymphocyte count despite normal villi and crypts. Functional abnormality of the small intestine has not previously been reported in patients with this jejunal biopsy abnormality. Abnormalities of permeability were also found in patients with idiopathic diarrhoea, folate deficiency, postinfectious or traveller's diarrhoea, small bowel Crohn's disease, and atopic eczema. These results show that sugar permeability tests have more potential in clinical investigation than merely serving as screening tests before jejunal biopsy. There are groups of patients without morphological changes in the small bowel in whom intestinal permeability is abnormal.
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PMID:Cellobiose/mannitol sugar permeability test complements biopsy histopathology in clinical investigation of the jejunum. 643 13

Aging is associated with increased incidence of folate deficiency. The mechanism responsible for the deficiency is not known but could include a decrease in the intestinal absorptive capacity for folates. Therefore, we examined the intestinal absorptive capacity for folate in young and old rats. We assessed the absorption of the natural folate derivative, 5-methyltetrahydrofolate in 3- and 25-month-old rats, using jejunal everted sacs. The kinetic parameters of 5-methyltetrahydrofolate absorption disclosed apparent Kt of 7.7 and 6.54 microM and Vmax of 0.96 and 1.14 nmol/g initial tissue wet weight/30 min in young and old rats, respectively. These data do not demonstrate an aging-associated decrease in the intestinal transport capacity for 5-methyltetrahydrofolate. Therefore the deficiency of folate found in the elderly is unlikely to be due to intestinal malabsorption of folate monoglutamates. Other mechanisms must play a role in the deficiency of folate seen in the elderly.
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PMID:Does aging affect the intestinal transport of 5-methyltetrahydrofolate? 651 May 74

The folic acid plasma level in 12 out of 13 children with thalassemia major was lower than 3 ng/ml. This deficiency is not due to intestinal malabsorption. Folate deficiency should then be provoked by an increased allowance due to the compensatory erythropoiesis and to the lack of. Folic acid level less then 3 ng/ml in 24% and not more then 6 ng/ml in 50% of thalassemic heterozygotic children has been found. Therefore the necessity of folic acid treatment in thalassemic children with a low blood transfusional therapy and in beta-thalassemic heterozygotic children has been recommended.
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PMID:[Behavior of blood folate in children with thalassemia major under transfusion therapy and in thalassemia trait]. 652 78

Folate deficiency and megaloblastic anemia occur in chronic renal failure. However, the possible role of intestinal malabsorption as a cause of the reported deficiency has not been investigated. Therefore, we examined the intestinal absorption of 5-methyltetrahydrofolate in rats made uremic by subtotal nephrectomy using in vivo perfusion technique and in vitro everted sac technique. The results were compared with those obtained in a group of sham-operated rats with normal renal function. The amount of 5-methyltetrahydrofolate absorbed in vivo was significantly lower in the uremic animals as compared to the control group. In contrast, no significant difference was found in the absorption of 5-methyltetrahydrofolate in vitro in the two groups. To mimic the uremic environment, the in vitro studies were repeated using jejunal sacs from normal animals filled with either buffer solution, or sera from uremic patients before and after dialysis. Their results showed a marked suppression of 5-methyltetrahydrofolate absorption with predialysis sera and a significant improvement with post dialysis sera. We conclude that intestinal absorption of 5-methyltetrahydrofolate is impaired in uremia. The results of the in vitro experiments suggest that the observed transport defect is due to some influence of uremic environment rather than to an acquired intrinsic defect of enterocytes in uremia.
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PMID:Intestinal absorption of 5-methyltetrahydrofolate in experimental uremia. 653 76

The consensus of this panel is that average dietary intake of folate in the free-living elderly population is probably adequate in most. Certainly more good data are needed; in addition, safe and reasonable dietary goals for folate intake are required. However, patients who have diseases requiring hospitalization or conditions for which institutionalization are required are obviously at greater risk. In addition, there is some evidence that the elderly poor in the US may be at greater risk of deficiency. Similarly, the evidence for folate deficiency based on blood assay data would seem to focus on the lower socioeconomic (largely Black and Hispanic) populations in addition to the hospitalized and institutionalized elderly. An additional factor in the genesis of folate deficiency among the aged is the factor of alcohol use which probably represents the single most important risk factor in folate deficiency among the elderly as well as among the nonelderly population. Although certain drugs such as anticonvulsants and sulfasalazine, may interfere with folate absorption or utilization, the number of elderly patients who are taking these drugs is relatively small and therefore this factor is not considered to be a major contributor to the problem of folate deficiency in the elderly. The question of folate malabsorption in the elderly has been examined. It is our conclusion that disease in the elderly population including gastric surgery and intestinal malabsorption, etc can certainly interfere with folate absorption but these problems are not widespread among the elderly population. There is only limited evidence that the physiological process of aging influences the intestinal absorption of folate.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Folate nutrition in the elderly. 676 71

Vitamin B12 and folate concentrations were determined by radioimmunoassay in groups of horses in Queensland. Highest serum vitamin B12 levels were found in supplemented performance horses. These, together with pastured horses that included pregnant and lactating mares, had significantly greater serum folate activity than permanently stabled animals. The range of red cell folate concentrations was much narrower in horses in training than from any other group. Red cell folate may be a better indicator of a horse's folate status than the serum folate value. Vitamin B12 and folate concentrations were highest in spring and summer. Small intestinal dysfunction in 2 horses was not associated with vitamin B12 or folate malabsorption. Serum folate levels returned to normal 24 h after intramuscular injections of 75 to 150 mg folic acid, whereas serum vitamin B12 values remained elevated for at least one week following injections of 8 to 10 mg to non-supplemented horses. None of the horses in this survey had evidence of vitamin B12 or folate deficiency, or showed significant haematological changes. Nevertheless, permanently stabled horses and some horses in training may require additional folic acid, preferably on a daily basis by the oral route. However, exogenous vitamin B12 administration does not appear to be justified.
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PMID:Serum and red cell folate and serum vitamin B12 levels in horses. 687 Jul 12

Seven patients being treated for acute lymphoblastic leukaemia between March 1976 and March 1981, in accordance with Medical Research Council protocols, developed clinical malabsorption while on maintenance chemotherapy. All of them received weekly methotrexate and 6 of the 7 were given co-trimoxazole. Five patients had folate deficiency. Stopping the anti-leukaemic therapy led to a resolution of gastrointestinal symptoms. A combined effect of methotrexate and co-trimoxazole is postulated.
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PMID:Enteropathy complicating maintenance therapy in acute lymphoblastic leukaemia. 698 27

The effects of oral contraception (OC) on folate and vitamin B12 metabolism are a subject of much controversy. Many studies indicate that OCs impair folate metabolsim and produce some degree of folate depletion, as demonstrated by slight but significant lower levels of folate in the serum and the erythrocytes, and by an increased urinary excretion of formiminoglutamic acid. These effects are unlikely to cause anemia or megalobastic changes in women who have a good dietary intake of folate. Since pregnant women are predisposed to the development of folate deficiency, it would be necessary when stopping the pill for desire of pregnancy to take folate supplements before becoming pregnant. OCs may also produce a low serum level of vitamin B12; this effect, however, is not associated with evidence of tissue depletion of vitamin B12, and does not have any great clinical significance; the effect may also be caused by vitamin B12 malabsorption rather than by OC treatment.
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PMID:Oral contraceptives: effect of folate and vitamin B12 metabolism. 703 44

In three different groups of patients presenting severe folate deficiency (purely nutritional folate deficiency, chronic alcoholism or various intestinal diseases), vitamin B12 absorption has been tested by Schilling test in order to investigate the possible effect of folate deficiency on B12 absorption. Following this study, it appears that folate deficiency in itself, even severe, cannot induce vitamin B12 malabsorption, since in the first group, consisting of malnourished old people, the Schilling test was always normal even in those who presented a lowered B12 serum level; in the group of patients with intestinal disease, the Schilling test was abnormal as expected in some patients; 3 alcoholics out of 12 presented a malabsorption of B12 on the Schilling test; the follow-up of 2 of them exhibited complete correction after normal diet and alcohol suppression. Consequently, folate deficiency does not seem responsible for a secondary B12 malabsorption unless another etiological factor is present, such as alcohol or ileopathy.
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PMID:Effect of folate deficiency on vitamin B12 absorption. 714 39

Higher serum folate levels were found among newly diagnosed, untreated patients with pancreatic insufficiency than among treated patients despite greater fat malabsorption in the former group. In vivo folate absorption tests using Tritium-labeled pteroylmonoglutamatic acid showed folate absorption to be enhanced in pancreatic insufficiency patients as compared to control subjects (P less than 0.01). Moreover, pancreatic extract significantly inhibited folate absorption in both normal subjects (P less than 0.05) and pancreatic insufficient patients (P less than 0.001). In vitro testing showed pancreatic extract to form insoluble complexes with folate. Such complex formation may diminish absorption of dietary folate and lead to folate deficiency. Since both pancreatic extract and bicarbonate are used in the treatment of pancreatic insufficiency and both are known to impair folate absorption, folate status should be monitored in patients being treated for pancreatic insufficiency; supplementation may be indicated.
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PMID:Impairment of folic acid absorption by oral pancreatic extracts. 737 75


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