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

The first case of megaloblastic anemia due to selective malabsorption of vitamin B(12) and vitamin B(12)-intrinsic factor is described in an otherwise normal female adult, in whom pernicious anemia had previously been diagnosed.
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PMID:Selective malabsorption of vitamin B12 and vitamin B12-intrinsic factor with megaloblastic anemia in an adult. 405 72

Three patients are described, and they provide further evidence that deficiency of folic acid and vitamin B(12) may sometimes affect small intestinal function. Malabsorption of both xylose and vitamin B(12) returned to normal in one patient after treatment of a megaloblastic anaemia due to dietary deficiency of folic acid. Impaired absorption of vitamin B(12) was corrected by vitamin B(12) therapy in the other two patients. The initial cause of the vitamin B(12) deficiency in one patient was not apparent, but she was taking Gynovlar 21, which may have been an aetiological factor. In the third patient the small intestinal defect was secondary to pernicious anaemia, and in a group of 98 other patients with pernicious anaemia intrinsic factor did not improve vitamin B(12) absorption in six, and only partially corrected absorption in 30. The significance of these observations is discussed.
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PMID:Effect of vitamin B12 and folic acid deficiency on small intestinal absorption. 536 38

A technique has been developed for accurately assaying serum and urine (57)Co cyanocobalamin during the conventional Schilling test. Serum and urine radioactivity in a large number of patients has been correlated and the precise normal limits have been determined by statistical analysis. The implications of this for investigating conditions other than pernicious anaemia and the malabsorption syndromes are stressed.
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PMID:An assessment of serum 57Co cyanocobalamin as an index of vitamin B12 absorption. 548 82

Results of the (57)Co vitamin B(12) plasma level absorption test are described in 163 patients. The use of intramuscular carbachol with the test and the presence or absence of current vitamin B(12) therapy did not affect the test results. Injection of 1,000 mug of unlabelled vitamin B(12) during the test augmented plasma levels in patients with normal absorption but tests without this injection gave satisfactory differentiation between the normal and malabsorption ranges. Results from patients having had a gastrectomy, ileal resection, or a past history of adult coeliac disease are also described. Amongst patients with presumed Addisonian pernicious anaemia, two with unresolved equivocal results and three with falsely normal results were found. The significance of these is discussed.
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PMID:Studies on the 57Co vitamin B12 plasma level absorption test. 548 84

The results of the measurement of vitamin B(12) absorption by counting the radioactivity of 5 ml. serum obtained eight to 10 hours after the ingestion of an oral dose of 0.5 mug. vitamin B(12) labelled with 0.5 muc. (57)Co are compared with those obtained with the urinary excretion (Schilling) test. Inadequate urine collection and impaired renal function were responsible for low results in the Schilling test in four of the 12 control subjects, and an incomplete urine collection in four patients with pernicious anaemia could have led to doubt about the validity of the low result. The measurement of serum radioactivity for 1,000 seconds gave conclusive results, the range in the patients with malabsorption of vitamin B(12) being between 0 and 24 counts per minute, and in the control subjects and other patients with megaloblastic anaemia between 28 and 64 counts per minute. The highest serum radioactivity level in a patient with pernicious anaemia was 19 counts per minute. Serum counting is simpler than the Schilling test and may be done alone when the patient's renal function is known to be poor, when urine collection is expected to be unreliable, or when the flushing dose of vitamin B(12) should be avoided. Otherwise there is an advantage in doing both tests together for confirmation.
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PMID:Measurement of intestinal absorption of 57-Co vitamin B-12 by serum counting. 592 10

The Schilling examination remains a popular means of evaluating in vivo absorption of vitamin B12. When absorption is abnormally low, the test may be repeated with addition of exogenous intrinsic factor (IF) in order to correct the IF deficiency that characterizes pernicious anemia. A dual-isotope variation provides a means of performing both stages of the test simultaneously, thereby speeding up the test and reducing dependence on complete urine collection. The dual-tracer test depends on no exchange of B12 moieties on the IF molecule. In vitro studies suggest that this exchange does take place, in a manner dependent on time, temperature, and pH. Furthermore, in vivo studies indicate that, when administered simultaneously, the absorption of unbound B12 is elevated, and IF-bound B12 is reduced, in pernicious-anemia patients, relative to the classic two-stage examination. A number of clinical studies indicate significant difficulty in resolving clinical diagnoses with the dual-tracer test. The potential weaknesses of the test discussed herein can be overcome by temporally separating the administration of the two B12 doses and by treating secondary malabsorption where it exists. An algorithm is offered for selecting the most suitable variation of the Schilling test to improve the accuracy of test results and the ease of performance.
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PMID:Schilling evaluation of pernicious anemia: current status. 647 Aug 5

A prototype food-bound vitamin B12 (food-B12) absorption test has been developed in which 57Co-B12 was incorporated in vitro into egg yolk (yolk-B12) and served to volunteers in 50-g cooked portions together with toast and coffee for breakfast. Six hours later, 1 mg nonlabeled B12 was given intramuscularly and 24-hour urine was collected for radioactivity measurement. In separate tests, the absorption of yolk-B12 and crystalline 57Co-B12 was equally poor in patients with pernicious anemia. However, in patients with simple gastric achlorhydria and those who had undergone gastric surgery, the assimilation of yolk-B12 was impaired greatly, whereas the absorption of crystalline radio-B12 was normal. Egg yolk labeled with 58Co-B12 was administered together with crystalline 57Co-B12 in a dual isotope test with results similar to those obtained when the tests were prepared separately. This yolk-58Co-B12 test with its ability to detect malabsorption of food-B12 may be considered as an addition to the first part of the Schilling test.
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PMID:Dual isotope Schilling test for measuring absorption of food-bound and free vitamin B12 simultaneously. 668 80

To evaluate the feasibility of gastroscopic screening for gastric malignancy in patients with pernicious anemia, all individuals treated with vitamin B12 in a well-defined population were identified. Individuals treated for an uncertain diagnosis were submitted to supplementary examinations. Of all individuals treated with vitamin B12 41% had unequivocal pernicious anemia, 13% possible pernicious anemia, 26% vitamin B12 malabsorption other than pernicious anemia, and 20% no verified vitamin B12 deficiency. The maximum crude prevalence of pernicious anemia was 1.98 per mile and the crude maximum incidence 16.7 x 10(-5) x year-1. The estimated annual cost of endoscopic gastric screening at 3-year intervals in patients with pernicious anemia younger than 75 years of age would be SEK 15,000/100,000 inhabitants, a cost that to a great extent could be financed by a more adequate prescription of vitamin B12 treatment.
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PMID:Prevalence and incidence of pernicious anemia. An evaluation for gastric screening. 671 30

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

The conventional method of measuring vitamin B12 absorption using a whole-body counter normally involves a delay of fourteen days before complete faecal excretion of unabsorbed B12 tracer can be assumed. A modified technique has been used which reduces the delay to four days. A non-absorbable tracer, 51Cr-chromic chloride, was administered firstly with 58Co-labelled vitamin B12 and then three hours later with 57Co-labelled vitamin B12 and then three hours later with 57Co-labelled vitamin B12 plus 50 mg hog intrinsic factor which normalises B12 malabsorption in patients with pernicious anaemia. Three days later, the residual whole-body activities of the three radionuclides were measured. The retention of 51Cr indicated the efficiency of faecal excretion of unabsorbed B12 tracer and could be used to quantify vitamin B12 absorption before complete excretion of unabsorbed B12 tracer. Vitamin B12 absorption values were measured at four days by this technique and compared with the corresponding values at fourteen days in 38 tests on 33 subjects, 16 of whom had pernicious anaemia. Excellent correlations between the results obtained at four and 14 days were obtained for both B12 tracers.
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PMID:A fast method of measuring vitamin B12 absorption using a whole-body counter. 683 44


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