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)

Increased concentrations of reactive oxygen species in children with depleted antioxidant defences have been implicated in a cycle of malnutrition, malabsorption, and infection leading to protracted diarrhoea. A rat model of chronic vitamin E deficiency has been used to study the effects of antioxidant depletion on jejunal structure and function in vitro. Basal intestinal short circuit current (Isc), a measure of net electrogenic ion movement across the intestinal epithelium, was greater in chronically vitamin E deficient jejuna than controls, as was the electrogenic secretory response to aminophylline and Escherichia coli STa but not to bethanechol. The galactose stimulated current was also greater in vitamin E deficient jejuna. Indices of lipid peroxidation (concentrations of thiobarbituric acid reactive substances and malondialdehyde) were increased in the vitamin E deficient small bowel. Small intestinal brush border membranes from vitamin E deficient animals displayed changes in both static and dynamic components of membrane fluidity measured by steady state fluorescence polarography. The results of these studies support the hypothesis that oxidative stress in subjects with compromised antioxidant defences results in small intestinal hypersecretion, which could predispose to or perpetuate protracted diarrhoea.
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PMID:Lipid peroxidation and electrogenic ion transport in the jejunum of the vitamin E deficient rat. 830 46

Intestinal absorption of glucose plays a key role in water economy as attested by the congenital and selective glucose and galactose malabsorption which is expressed as severe watery diarrhea just after birth, leading to life-threatening dehydration. This syndrome, transmitted on an autosomal recessive mode, is the consequence of a functional defect of the glucose-sodium cotransporter at the luminal membrane of the enterocyte of the small intestine. In one family, this defect was associated with a missense mutation at position 92 of the SGLT1 gene coding for the cotransporter. The mutant RNA reproduced the transport defect after injection in xenopus oocytes. These results confirm the genetic origin of the congenital defect; in addition they indicate that the study of the relationship between phenotype and genotype of congenital defects of intestinal transport may help in the understanding of basic intestinal functions in relation with human nutrition.
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PMID:[Thirty years of research on congenital glucose and galactose malabsorption: from phenotype to genotype]. 831 9

To determine the effect of age on the regulation of intestinal nutrient absorption, we fed young (7.6-mo-old) and aged (24.8-mo-old) C57BL mice diets designed to stimulate in vitro sugar or amino acid uptake in the isolated small intestine. In each age group, diet had no effect on feeding rates and body weights. D-Glucose and D-fructose uptakes by the small intestine each increased by about two times in young and 1.5 times in aged mice fed high carbohydrate diets as compared with those fed no carbohydrate. Adaptive increases in uptake by the aged group were not only reduced but also restricted to more proximal regions of the small intestine. In both age groups, diet-stimulated increases in D-glucose transport were accompanied by parallel increases in number of Na(+)-D-glucose cotransporters as estimated by specific phlorizin binding. Diet had no effect on transporter Kd for phlorizin, turnover rate of each transporter, mucosal mass or mucosal permeability. A high protein diet stimulated the uptake of L-aspartate and L-proline in young mice and of only L-aspartate in aged mice. Uptake of essential amino acids and of nonessential amino acids sharing transporters with essential ones were not regulated. Although aged mice possess adaptive mechanisms to diet that are similar to those in young mice, the effectiveness of these mechanisms may be impaired with age and may result in malabsorption symptoms so prevalent in the elderly.
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PMID:Regulation of intestinal nutrient transport is impaired in aged mice. 846 53

Intestinal function is poorly defined in patients with HIV infection. Absorptive capacity and intestinal permeability were assessed using 3-O-methyl-D-glucose, D-xylose, L-rhamnose, and lactulose in 88 HIV infected patients and the findings were correlated with the degree of immunosuppression (CD4 counts), diarrhoea, wasting, intestinal pathogen status, and histomorphometric analysis of jejunal biopsy samples. Malabsorption of 3-O-methyl-D-glucose and D-xylose was prevalent in all groups of patients with AIDS but not in asymptomatic, well patients with HIV. Malabsorption correlated significantly (r = 0.34-0.56, p < 0.005) with the degree of immune suppression and with body mass index. Increased intestinal permeability was found in all subgroups of patients. The changes in absorption-permeability were of comparable severity to those found in patients with untreated coeliac disease. Jejunal histology, however, showed only mild changes in the villus height/crypt depth ratio as compared with subtotal villus atrophy in coeliac disease. Malabsorption and increased intestinal permeability are common in AIDS patients. Malabsorption, which has nutritional implications, relates more to immune suppression than jejunal morphological changes.
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PMID:Intestinal absorptive capacity, intestinal permeability and jejunal histology in HIV and their relation to diarrhoea. 854 36

Cotransporters harness ion gradients to drive 'active' transport of substrates into cells, for example, the Na+/glucose cotransporter (SGLT1) couples sugar transport to Na+ gradients across the intestinal brush border. Glucose-Galactose Malabsorption (GGM) is caused by a defect in SGLT1. The phenotype is neonatal onset of diarrhea that results in death unless these sugars are removed from the diet. Previously we showed that two sisters with GGM had a missense mutation in the SGLT1 gene. The gene has now been screened in 30 new patients, and a heterologous expression system has been used to link the mutations to the phenotype.
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PMID:Defects in Na+/glucose cotransporter (SGLT1) trafficking and function cause glucose-galactose malabsorption. 856 65

The aim of the study was to determine the prevalence of selective lactose malabsorption (SLM) in Khants, a small finno-ugric nation living in West Siberia. A total of 80 Khants from the Surgut region (Tyumen territory) were studied. The diagnosis of SLM was based on the evidence obtained at a 50 g lactose and, if possible, a 25 g + 25 g galactose-glucose loads. In 6 cases electron-microscopic examination of the duodenal mucosa was performed. The prevalence of SLM in the Khants reached 93-94% being the highest in CIS.
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PMID:[Prevalence of selective lactose malabsorption in Khants]. 864

The stomach stores food and starts digesting protein and fat. Lipids, sugars, certain amino acids, and nutrients of high osmolality trigger sensory mechanisms from the intestine which inhibit gastric emptying. Food rich in carbohydrates leaves the stomach slower than protein-rich food, and emptying is slowest after a meal containing lipid. For carbohydrate beverages, the gastric emptying rate is primarily determined by the volume, caloric content, and osmolality of fluid ingested. Gastric emptying rates vary among isocaloric beverages of different type (e.g., sucrose, fructose, galactose) or forms (e.g., maltodextrins, starches) of carbohydrate. For instance, gastric emptying is faster for a fructose solution compared with isocaloric glucose and galactose solutions. A maltodextrin or a sucrose solution empties faster than a glucose solution. This is possibly due to the greater inhibitory feedback associated with the introduction of glucose in the duodenum. In addition, fruit juices contain soluble fibers which further modulate the gastric emptying. Noninvasive methods to study gastric emptying have recently been developed. The pattern of the myoelectric activity of the gastric contraction and the effect of meals on this pattern can now be recorded by cutaneous electrodes. In healthy children ingesting different juices, the myoelectric pattern of the stomach (indicator of the gastric emptying) correlates with the carbohydrate absorption (measured by breath hydrogen excretion). Fast gastric emptying was associated with greater production of breath hydrogen. The malabsorption of juice carbohydrates may in part be related to their effect on gastric motility.
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PMID:Gastric physiology and function: effects of fruit juices. 889 79

Transport proteins such as channels and transporters play important roles in the maintenance of intracellular homeostasis. Genes for transport proteins have been cloned one after the other in recent years, and mutations in these transport protein genes have been identified in the pathogenesis of a number of hereditary diseases. These diseases include Liddle's syndrome, long QT syndrome, hyperkalemic periodic paralysis, cystic fibrosis, myotonia congenita, nephrogenic diabetes inspidus, glucose/galactose malabsorption, cystinuria, and Wilson's disease. Gene mutations in several receptors, including vasopressin V2 receptor, dihydropyridine receptor, and Ca2+ -sensing receptor, also cause disorders of membrane transport, leading to diseases. Further advances in basic science are expected to provide us with a detailed understanding of the abnormality in the 3rd/4th structure of mutated transport proteins.
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PMID:[Diseases caused by disorders of membrane transport: an overview]. 890 8

Methotrexate (MTX) induces damage to the small intestine, resulting in malabsorption and diarrhea. We found that the coadministration of vitamin A (VA) with MTX protected the small intestine from MTX-induced damage. In this study, the permeability of D-glucose, D-xylose and L-leucine through the small intestine of rats treated with MTX and/or VA was studied using everted segments of small intestine. MTX treatment decreased permeability and VA coadministration prevented the decrease. The transport of D-glucose in the small intestine of MTX plus VA- and VA-treated rats and of control rats followed Michaelis-Menten kinetics, in contrast to the transport kinetics in MTX-treated rats. The pharmacokinetics of orally administered [14C]-D-glucose in control rats and MTX- and/or VA-treated rats was also studied. The bioavailability of D-glucose in MTX-treated rats was lower than in the other three groups. VA coadministration improved the bioavailability of D-glucose. Thus, it seems likely that VA ameliorates MTX-induced malabsorption.
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PMID:Amelioration of methotrexate-induced malabsorption by vitamin A. 899 27

Intestinal adaptation is a complex physiologic process that is not completely understood. Intravenous short-chain fatty acids (SCFAs) enhance intestinal adaptation after 80% enterectomy in rats. The purpose of this study was to examine rapid responses to SCFA-supplemented total parenteral nutrition (TPN) in the normal small intestine. After jugular catheterization, 31 Sprague-Dawley rats (weighing 258 +/- 3 g) were randomly assigned to receive standard TPN or an isoenergetic, isonitrogenous TPN solution supplemented with SCFAs (TPN+SCFA). Intestinal samples were obtained after 24 or 72 h of nutrient infusion. TPN+SCFA for 24 h increased (P < 0.05) the ileal RNA concentration (microg RNA/mg ileum) whereas TPN+SCFA for 72 h increased (P < 0.05) the ileal DNA concentration (microg DNA/mg ileum) and decreased (P < 0.05) the ileal protein concentration (microg protein/mg ileum). Ileal proglucagon mRNA abundance was elevated (P < 0.05) after 24 h of TPN+SCFA infusion and returned to levels seen with control TPN by 72 h. Glucose transporter 2 (GLUT2) mRNA was significantly higher (P < 0.05) in the TPN+SCFA groups at both time points when compared with control TPN groups. Ileal GLUT2 protein abundance in the 72-h TPN+SCFA group was significantly higher (P < 0.05) than that of all other groups. Sodium-glucose cotransporter (SGLT-1) mRNA and protein abundance and uptake of D-fructose and D-glucose did not differ between groups. Jejunal uptake of L-glucose and lauric acid was significantly higher (P < 0.05) after 72 h of TPN+SCFA than after 24 h, whereas the 24- and 72-h TPN groups did not differ. In summary, SCFAs led to rapid changes in ileal proglucagon and glucose transporter expression in rats receiving TPN and provide insights into therapeutic management of individuals with short bowel syndrome or intestinal malabsorption syndromes.
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PMID:Short-chain fatty acid-supplemented total parenteral nutrition alters intestinal structure, glucose transporter 2 (GLUT2) mRNA and protein, and proglucagon mRNA abundance in normal rats. 966 5


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