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

The intraluminal fate of orally administered radioactive vitamin B12 has been studied in control subjects with normal vitamin B12 absorption and those with vitamin B12 malabsorption due to tropical sprue. In control subjects 1 to 21% of the dose was bound to sedimentable material and 37 to 75% was bound to immunoreactive intrinsic factor. In subjects with vitamin B12 malabsorption due to tropical sprue, the results were identical with the control subjects. Bacteriological studies showed a statistically significant correlation between both the number of flora in the jejunum and the number of bacteroides in both the jejunum and ileum and vitamin B12 malabsorption. In patients with tropical sprue who have normal intrinsic factor secretion, the vitamin B12 absorptive defect is not due to binding of the vitamin to bacteria or to alteration to the intrinsic factor vitamin B12 complex in the intestinal lumen. The lesion appears to be one of the mucosal cell receptors or of the cells themselves, possibly caused by bacterial toxins.
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PMID:Vitamin B12 absorption--a study of intraluminal events in control subjects and patients with tropical sprue. 0 57

To determine the mechanism by which pancreatic extract (PE) corrects the malabsorption of vitamin B12 in chronic pancreatic insufficiency (CPI), the following hypotheses were investigated: Firstly, PE might stimulate the absorption of vitamin B12 by changing the intestinal pH, secondly PE might stimulate the intestinal uptake of unbound vitamin B12, thirdly PE might abolish the inhibitory effect of vitamin B12 binders on the intestinal uptake of vitamin B12 bound to intrinsic factor (IF). PE had no effect on the pH in the small intestine and did not stimulate the uptake of unbound 57CoB12 by perfused rat intestinal segments. Preincubation of 57CoB12-IF with a non-IF B12-binder from human saliva (R-binder) reduced the uptake of 57CoB12 from 18.5 pg per cm intestine +/- 3.4 S.E.M. to 7.8 +/- 1.6 (p less than 0.02). PE abolished this inhibitory effect (p less than 0.05). The results indicate that PE corrects the malabsorption of vitamin B12 in CPI by an effect on non-IF B12- binders.
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PMID:Pancreatic extract and the intestinal uptake of vitamin B12. III. Stimulatory effect in the presence of a non-intrinsic factor vitamin B12 binder. 1 12

A case of Whipple's disease in a female is described. Malabsorption of iron, vitamin B12, folic acid and fat was present. These abnormalities reverted to normal after introduction of co-trimoxazole therapy. The patient's humoral immune system was normal, in contrast to impairment of cell-mediated immunity, which has not improved in spite of co-trimoxazole treatment for 2 years, and a therapeutic trial of levamisole. These findings are further evidence that there may be a primary immune deficiency in patients with Whipple's disease.
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PMID:Whipple's disease in a female with impaired cell-mediated immunity unresponsive to co-trimoxazole and levamisole therapy. 7 42

Pepsin had no effect on the vitamin B12 binder in human saliva (R-binder), while trypsin was found to reduce the apparent molecular weight of the R-binder and to release vitamin B12 from the R-B12complex of human saliva and human gastric juice (HGJ). Trypsin had no effect on the molecular weight and biological activity of intrinsic factor (IF) in HGJ, as demonstrated by gel filtration on Sephadex G-150 and the uptake of IF-B12 by guinea pig intestinal brush borders. An extract of purified guinea pig intestinal lysosomes was also without effect on the molecular weight and the biological activity of IF but was found to release vitamin B12 from the R-B12 complex. The results support the observation that the external pancreatic secretion corrects malabsorption of vitamin B12 by an effect on the non-IF protein in the intestinal juice. Moreover, the results indicate that lysosomal enzymes are not involved in the intestinal absorption of vitamin B12.
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PMID:The effect of proteolytic enzymes on the vitamin B12-binding proteins of human gastric juice and saliva. 12

In six patients with pernicious anemia, absorption of vitamin B12 bound to intrinsic factor was low as measured by the Schilling's test. Collection of urine was complete and the activity of intrinsic factor used was checked in other pernicious anemia patients. Nutritional deficiency, drug induced malabsorption, ileal or pancreatic diseases were excluded by clinical, radiological and biological investigations. This vitamin B12 malabsorption was selective and reversible within a few months after treatment with parenteral vitamin B12. Mechanisms of this ileal dysfunction are discussed.
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PMID:[Transient malabsorption of Vitamin B12 bound to intrinsic factor in pernicious anemia (author's transl)]. 12 17

A baby girl, born prematurely and with Down's syndrome, is hospitalized at the age of 51 days for a megaloblastic anemia. The anemia was caused by a selective malabsorption of vitamin B12 (Imerslund's syndrome), even in presence of intrinsic factor. The pathogenesis of different causes of vitamin B12 deficiency is discussed and the favourable development of this case after four years of treatment is shown.
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PMID:[Congenital malabsorption of vitamin B12 (Imerslund's syndrome) in a premature girl with Down's syndrome (author's transl)]. 15 16

The diagnostic interest of a search for anti-intrinsic factor antibodies is emphasized from the authors research on more than 200 patients or controls. Antibodies of type I, so-called blocking antibodies, were detected in 66% of cases where the diagnosis of pernicious anemia was made. Type II, so-called precipitating antibodies, were found in 47% of patients with antibodies of type I and only in the latter. Certain etiological factors, already noted in the world literature, were found, in particular the link with the female sex and with blood group A. The specificity of these antibodies is very great and false positives are exceptional. We did not find them in any of the 104 controls. They were observed, however, in 5 of the 56 patients where the diagnosis of pernicious anemia was not definite, but it is likely that, in these 5 cases, pernicious anemia existed with some other disease. Our study also showed the limits of other methods of investigation of this disease; hypovitaminimia B12 is often corrected by treatment without proper inductions and B12 malabsorption on the Schilling test may not be corrected by the addition of intrinsic factor.
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PMID:[Search for anti-intrinsic factor antibodies in the diagnosis of Biermer's anemia]. 16 41

Serum vitamin B12 concentrations were measured in 60 patients undergoing repetitive hemodialysis and in undialyzed patients with chronic renal failure. Dialysis patients had significantly lower serum vitamin B12 levels than the nondialyzed group 321 +/- SEM 38 pg/ml versus 793 +/- 100), and 19 of 60 dialysis patients had vitamin B12 Concentrations less than 200 pg/ml. Folic acid concentration was 5 times greater in dialysis than in nondialysis patients, presumably because the latter received daily supplementation with folic acid. Serum vitamin B12 concentrations fell progressively during the patient's course of dialysis. Neither inadequate dietary intake nor vitamin B12 malabsorption accounted for the differences in the serum vitamin B12 concentrations seen in the two groups. Serum vitamin B12 levels and nerve conduction velocities in 51 dialyzed patients showed a significant correlation. Six dialyzed patients with low serum vitamin B12 levels and slow nerve conduction velocities showed improvement in nerve conduction (+ 14.6 +/- 3.3 m/sec) following the parenteral use of pharmacological doses of vitamin B12. The cause of the low serum vitamin B12 concentration is not clear, nevertheless, alterations in serum vitamin B12 seen in some dialysis patients may be a factor in the persistence of abnormal nerve conduction and may be reversed with large doses of parenteral vitamin B12.
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PMID:Vitamin B12 levels and nerve conduction velocities in patients undergoing maintenance hemodialysis. 18 Jul 88

The authors report 12 cases of neurological syndromes due to folic acid deficiency, due in 8 cases to chronic alcoholism. In 5 cases there was polyneuritis, 3 cases had cerebellar atrophy, whilst 4 patients had subacute combined degeneration of the cord. Folic acid deficiency occurred alone in five cases out of twelve, as in 3 cases vitamin B1 deficiency was associated, and in four cases there was malabsorption of vitamin B12. A neuropathological study of these cases showed: 1) moderate involvement of the mamillary tubercles as observed in deficiency encephalopathies. 2) severe peripheral nerve involvement especially of axonal type. 3) involvement of the anterior horns of the spinal cord with appearances of central chromatolysis and a few atrophic neurones.
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PMID:[Role of folic-acid deficiency in deficiency diseases of the nervous system. Apropos of 12 cases including an anatomo-clinical case]. 19 44

A new rapid and accurate method for detecting vitamin B12-intrinsic factor (IF-B12) receptors was used to study the distribution of mucosal IF-B12 receptors in three human small intestines. IF-B12 receptors in human intestine are present in significant amounts in the entire distal three-fifths of intestine. Triokinase activity is absent in the distal two-fifths of intestine, and tryptophan oxygenase is present only in the distal one-sixth, or most terminal part of the ileum. These data suggest (1) biochemical functions in the ileum have different anatomical distributions, (2) IF-B12 receptors correspond most closely with the accepted anatomical definitions of the ileum, and (3) vitamin B12 malabsorption seen in resection or disease of terminal ileum may not be attributable solely to a deficiency of ileal receptors.
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PMID:Distribution of intrinsic factor-vitamin B12 receptors in human intestine. 19 33


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