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

Vitamin A absorption was studied in a group of 28 adult patients with ascariasis and 12 healthy adult controls, using a simplified vitamin A absorption test. In over 70% of the patients with ascariasis malabsorption of vitamin A was demonstrated. Stool egg counts for ascaris were not related to the degree of vitamin A malabsorption. Of the 23 patients in whom a D-xylose absorption test was performed, seven showed excretion less than 20% in 5 hr. Immediately after expulsion of the worms, vitamin A absorption improved in 13 out of 14 patients tested (in nine to normal level). The results of this study suggest that ascariasis in populations on marginal intakes of vitamin A and its precursors is an important contributing factor in producing clinical vitamin A deficiency.
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PMID:Vitamin A absorption in ascariasis. 99 48

Vitamin A is necessary to maintain the integrity and the differentiation of epithelia of the skin and adnexa. Evident deficiency of vitamin A in chronic diseases, malabsorption and liver affections may result in skin xerosis, follicular keratosis, and metaplasia of mucous membranes. The remarkable toxicity of vitamin A in high doses does not recommend its usage in dermatology. On the contrary the employ of retinoids, synthetic derivatives of vitamin A, brings to excellent results. These vitamin A compounds are much more effective, even if they show important side-effects. Etretinate and isotretinoin are widely used in psoriasis, keratinization disorders, and severe acne. Vitamin E functions in skin biology are not totally known. Vitamin E is used in the treatment of dermolytic recessive epidermolysis bullosa, with controversial results.
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PMID:[Vitamin A and vitamin E in dermatology]. 391 47

Retinol and retinyl esters are measured in serum or plasma samples by gradient, normal-phase, adsorption "high-performance" liquid chromatography, with ultraviolet detection at 325 nm. The four major circulating retinyl esters in humans (esters of palmitate, stearate, oleate, and linoleate) are coeluted as a single peak. Retinyl acetate is included as an internal standard, to correct for variable recovery. Retinol values so measured correlated well (r = 0.88) with those by a widely used reversed-phase chromatographic technique (Clin Chem 1983;29:708-12). The mean retinol concentration was 570 (SEM 17) micrograms/L and the mean for retinyl esters was 33 (SEM 4) micrograms/L as determined in samples from 88 fasting young adults. Concentrations of retinol in plasma as low as 50 micrograms/L can be detected in 100-microL samples, as can 10 micrograms of retinyl esters per liter. Using this method, we measured absorption of low doses of vitamin A, which may provide a more physiological approach to assessment of fat malabsorption. Additionally, the procedure proved useful for quickly screening for vitamin A toxicity. Major advantages include small sample size, direct injection of the extract ed sample without evaporation, rapid elution pattern, co-elution of major retinyl esters as a single peak, and low limit of detection.
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PMID:Determination of retinyl esters and retinol in serum or plasma by normal-phase liquid chromatography: method and applications. 394 Jul 33

Vitamin A deficiency remains an important cause of ocular morbidity among patients with chronic liver disease and lipid malabsorption, and is a major cause of blindness in developing countries. Early ocular surface changes include keratinization of the conjunctiva and development of superficial punctate keratopathy. More severe deficiency results in corneal keratinization, ulceration, and necrosis. Vitamin A is necessary for normal differentiation of nonsquamous epithelium; keratinization is a direct consequence of its deficiency. Exposure exacerbates the process and surface phenomena, especially localized drying from loss of mucus-secreting goblet cells, reduced aqueous tear production, and irregularities of the keratinized surface may all contribute to stromal melting, which can occur in the absence of inflammatory infiltration or bacterial invasion. Surface abnormalities respond rapidly to systemic vitamin A. Significantly, corneal changes disappear long before the reappearance of goblet cells. Inflammation sometimes masks or reverses the xerotic process.
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PMID:Effects of vitamin A deficiency on the ocular surface. 660 47

Vitamin A and zinc metabolism are affected both by ethanol and by hepatic cirrhosis. Ethanol causes abnormal dark adaptation by acting as a competitive inhibitor with retinol for alcohol dehydrogenase in the eye. In animals oral ethanol intake results in increased losses of zinc by the urinary and fecal routes. Vitamin A malnutrition in cirrhotics may be caused by poor diet, malabsorption, decreased hepatic vitamin A uptake, and decreased hepatic storage capacity for vitamin A. In some cirrhotic patients zinc deficiency and or protein deficiency may limit the ability to respond to vitamin A. Combined vitamin A and zinc deficiencies are common in cirrhotics and either may result in abnormal dark adaptation or impaired taste and smell. The interaction of these two micro-nutrients must be kept in mind by the clinician caring for alcoholic or alcoholic cirrhotic patients.
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PMID:Vitamin A and zinc metabolism in alcoholism. 700 92

1. Vitamin A: There are very few reports on vitamin A deficiency in Japan because of the rising national status of nutrition, while vitamin A deficiency is still an important nutritional problem in developing and poorly developed countries. In the pediatric field, relationship between vitamin A nutrition and the mechanism for development of bronchopulmonary dysplasia have been discussed, since vitamin A acts as a protector from the keratinization of epithelial cells in the mucosal layer and the skin. The changes in the lung tissues with inadequately supplied vitamin A, probably cause the chronic lung disease resulting from mechanical ventilation in neonates, in whom the plasma vitamin A and retinol binding protein levels are usually low. 2. Vitamin E: In keeping with the view that newborn infants and especially premature infants suffer from vitamin E deficiency. On the basis of recent findings of the vitamin E content in the neonatal cells, the previous concept would agree, as an existing marginal deficiency in neonates. The neurologic deficits manifested in a beta-lipoproteinemia is confirmed to be vitamin deficiency in humans. It has also become clear that similar neurologic impairment occurs in other chronic fat malabsorptive states, such as cholestatic liver diseases, extensive resection of the gut. More recently several patients with spinocerebellar degeneration from vitamin E deficiency without other evidence of malabsorption in whom progression of the diseases is terminated by the vitamin E therapy (isolated vitamin E deficiency) have been reported. The above items are discussed.
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PMID:[Vitamin A and E deficiency in children, including the marginal deficiency]. 848 80

Patients with the acquired immunodeficiency syndrome (AIDS) are characterized by a decrease in the number of T helper cells, a defect that is linked to the impaired immunologic competence. Vitamin A and its dietary precursor, beta-carotene, increase absolute T helper cell counts as well as indices of T cell function in both human and animal models. To determine if short-term beta-carotene treatment affects T lymphocyte subsets in patients with AIDS, a single-blind, non-randomized clinical trial of beta-carotene was performed in seven patients with AIDS. Enrollment criteria included no evidence of: a) active opportunistic infection: b) greater than 1 kilogram change in weight in the month preceding enrollment; c) chronic diarrhea or malabsorption; and d) hepatic disease or significant anemia. Beta-carotene was given with meals in two divided doses of 60 mg/day for four weeks; this was followed by no therapy for six weeks. Samples for total white blood cell, lymphocyte and T lymphocyte subset counts were measured at baseline, at the end of four weeks of treatment and another six weeks after treatment had stopped. P24 antigen, beta-2 microglobulin and liver function tests were also measured. All subjects tolerated the treatment well without evidence of toxicity. In response to beta-carotene, total lymphocyte counts rose by 66 percent (.05 < p < .10), and CD4+ cells rose slightly, but insignificantly, in the entire group. In all three of the patients who had baseline CD4+ cells greater than 10/microliters, however, the mean absolute increase in CD4+ cells in response to beta-carotene was 53 +/- 10 cells/microliters (p < .01). Six weeks off beta-carotene treatment, the absolute CD4+ cell count returned to pretreatment levels (p < .01). No change was observed in CD8+ cells. P24 antigen and beta-2 microglobulin did not change during treatment. These preliminary observations suggest that short-term treatment with beta-carotene may increase CD4+ cell counts in patients with AIDS who have greater than 10 cells/microliters.
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PMID:The effect of supplemental beta-carotene on immunologic indices in patients with AIDS: a pilot study. 874 63

Systemic mastocytosis is characterized by an increased number of mast cells in multiple organs particularly skin. A 55-year-old man with mastocytosis presented with nyctalopia caused by malabsorption of vitamin A. Diagnosis was made by documenting a low vitamin A level and an ERG that showed rod-cone deficiency with rods affected more than cones. Vitamin A therapy led to return of good visual function. To our knowledge, this is the first reported case of mastocytosis induced nyctalopia. Vitamin A deficiency should be considered as a potential cause of visual loss in patients with sudden onset of night blindness.
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PMID:Mastocytosis-induced nyctalopia. 879 68

Vitamin A is an essential nutrient for epithelial cell maintenance and repair, and it is known that infectious stresses may depress plasma vitamin A concentrations. Patients with cystic fibrosis are at risk for vitamin A deficiency because of fat malabsorption as well as for the inflammatory stresses of pulmonary exacerbations of their underlying disease. We therefore hypothesized that acute pulmonary exacerbations of CF would depress plasma retinol concentrations, and that these concentrations would return to baseline values when clinical symptoms improved. We prospectively studied 35 CF patients (mean age: 24.2 y) consecutively admitted with pulmonary exacerbations. Plasma retinol, vitamin E, retinol binding protein (RBP), and C-reactive protein (CRP) concentrations were measured on hospital admission and discharge. Dietary intake was measured by using a semiquantitative food-frequency questionnaire. Regression analysis was used to identify significant clinical and laboratory correlates of retinol concentrations. On admission, mean (+/- SD) concentrations of plasma retinol were 1.14 +/- 0.5 mumol/L compared with 1.70 +/- 0.6 mumol/L on discharge (P = 0.0001). Of 35 subjects, 8 (22.9%) had plasma retinol concentrations considered to be in the deficient range (< 0.70 mumol/L). Concurrently, mean concentrations of plasma RBP increased during hospital admission (from 1.46 to 2.24 mumol/L, P = 0.003), and the mean CRP concentration declined (from 25.7 to 9.8 mg/L, P = 0.002). Significant positive correlations were found between plasma retinol concentrations at admission and age, weight, body mass index, triceps-skinfold-thickness percentile, midupper arm circumference percentile, plasma vitamin E, and RBP concentration, thus suggesting that better-nourished patients had more optimal vitamin A status. At admission, plasma retinol concentrations were negatively correlated with maximum body temperature and CRP concentrations, which indicated that the body's acute-phase response was associated with the depression in retinol concentrations. We conclude that plasma retinol concentrations are depressed in acute pulmonary exacerbations of cystic fibrosis, and that concentrations considered to be in the deficient range are common. Vitamin A metabolism during acute inflammatory stress deserves further study.
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PMID:Vitamin A status in acute exacerbations of cystic fibrosis. 883 11

Patients with cystic fibrosis (CF) have significantly decreased plasma concentrations of antioxidant vitamins which is considered to result both from fat malabsorption and from chronic pulmonary infection. The aim of this study was to investigate levels of vitamin A and beta-carotene in plasma of CF subjects with pancreatic exocrine insufficiency. In thirty CF patients mean plasma concentrations of vitamin A (1.17 micromol/l) was lower by 30% and that of beta-carotene (1.3 micromol/l) by 60% than in healthy children. Vitamin A level was positively correlated with beta-carotene (r=0.67; p<0.001). Ratios of beta-carotene to total cholesterol and cholesterol of LDL (low density lipoprotein) were 40% lower than in the control group. We conclude that in our CF patients the concentration of beta-carotene does not seem to be sufficient to inhibit lipid peroxidation especially of LDL fraction.
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PMID:[Concentration of plasma beta-carotene in cystic fibrosis children with pancreatic insufficiency]. 1263 81


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