Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.108 (lactase)
 2,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Jaundice phototherapy is associated with a significant incidence of watery diarrhea. We have postulated that acute intestinal secretion, rather than malabsorption of dietary carbohydrate, is an effect of a photoproduct of bilirubin upon the intestinal mucosa. Because of major effect of phototherapy is the hepatic excretion of nonconjugated bilirubin, we investigated the effect of bilirubin on small intestinal function in the hamster in vivo. The entire small intestine was luminally perfused in vivo with solutions containing bilirubin (0.125 to 0.75 mmole/liter) and net water and sodium fluxes were measured. Control animals absorbed both water (J H2O(net) = 58.9 microliter/min/g) and sodium (J Na(net) = 4.55 microEq/min/g), but animals perfused with bilirubin (greater than or equal to 0.25 mmole/liter) exhibited secretion of water (J H2O(net) = -39.0--85.9) and sodium (J Na(net)=-9.91--18.24). The rate of water secretion was positively related to the concentration of bilirubin in the infusate (r=0.749; p less than 0.001). The concentration of bilirubin in ultrafiltrates of perfusate was likewise positively related to its concentration in the infusate (r = 0.844; p less than 0.001), indicating the potential importance of soluble forms of bilirubin in inducing secretion. Possible epithelial injury was studied by measuring the concentration of DNA in the perfusate and the activity of disaccharidases in postperfusion mucosa, and the possible role of cyclic adenosine monophosphate as a mediator of the secretory process was investigated by determining its concentration in postperfusion mucosa. Perfusion with 0.5 mM bilirubin, which produced significant secretion, did not cause loss of DNA (0.284 versus 0.244 mg/liter) or mucosal lactase activity (56 versus 53 units/g) or enhancement of cyclic adenosine monophosphate concentration (14.9 versus 14.12 pmoles/mg protein).
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PMID:The effect of bilirubin on the function of hamster small intestine. 626 58

Pigs reared on a milk substitute from two days old often developed diarrhoea, but suckled littermates remained healthy. Only in a few pigs was diarrhoea associated with the presence of rotavirus. Rotavirus was also present in some healthy pigs, and was associated with a reduction in villus length. Pigs with diarrhoea usually had an increased amount of digesta in the stomach and a reduction in lactase activity in the small intestine but villus length was unchanged. There was no evidence of lactose malabsorption.
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PMID:Incidence of rotavirus in artificially reared pigs and some effects of diarrhoea on the physiology and histology of the gastrointestinal tract. 628 12

Ten pediatric patients investigated for chronic diarrhea, chronic weight loss, or failure to thrive were found on intestinal biopsy and/or in a duodenal aspirate to have Giardia lamblia. Serum immunoglobulin levels were normal or elevated in all patients. Three children had increased excretion of fecal fat and three other children had low D-xylose absorption. Jejunal biopsy specimens showed two severe, three moderate, and two mild morphological abnormalities, and three were normal. Except for lactase deficiency, disaccharidase activities correlated poorly with the severity of mucosal damage on biopsy. Steatorrhea was seen only with the more normal biopsies. Immunofluorescent staining of the biopsies for IgG, IgM, IgA, and secretory piece revealed no immune defects. Thus, there was no single malabsorption defect associated with giardiasis, and the specific defects did not necessarily correlate with morphological changes.
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PMID:Giardiasis in childhood: poor clinical and histological correlations. 635 23

Streptococcus durans was isolated from a foal with profuse watery diarrhea and caused a similar syndrome when inoculated into foals via the orogastric route. The most consistent and striking histological feature was the extensive colonization of the mucosal surface of the small intestine by S. durans. Associated mucosal changes were mild to modeate, and brush border lactase and alkaline phosphatase production were depressed. S. durans also induced acute diarrhea in young gnotobiotic piglets. Mucosal changes were mild and, as with foals, the mucosal surface of the small intestine was colonized by the organism.
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PMID:Streptococcus durans: an unexpected enteropathogen of foals. 638 98

Large quantities of yogurt are consumed by some lactase-deficient population groups. We used breath hydrogen measurements to determine whether lactase-deficient subjects absorbed lactose in yogurt better than lactose in milk. Ingestion of 18 g of lactose in yogurt resulted in only about one third as much hydrogen excretion as a similar load of lactose in milk or water, indicating a much better absorption of lactose in yogurt. Ingestion of yogurt also resulted in fewer reports of diarrhea or flatulence than did a similar quantity of lactose ingested in milk or a water solution. The enhanced absorption of lactose in yogurt appeared to result from the intraintestinal digestion of lactose by lactase released from the yogurt organisms. This autodigesting feature makes yogurt a well-tolerated source of milk for lactase-deficient persons and may explain the widespread consumption of yogurt by lactase-deficient population groups.
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PMID:Yogurt--an autodigesting source of lactose. 641 39

We report results on determinations of small intestinal brush-border enzyme activities in 22 children (aged 11 months to 14 years) with giardiasis. In particular, activities of disaccharidases (lactase, sucrase, maltase) and of alkaline phosphatase were investigated. Forty-one percent of the patients, irrespective of age, had a demonstrable depression of disaccharidase activities, usually in a combination involving two or more enzymes. A depression of intestinal alkaline phosphatase activity was present in 33% of patients, and only in those who demonstrated disaccharidase deficiencies. Mild villus atrophy was present in two mucosal specimens, whereas all others showed normal villus morphology by light microscopy. The results obtained in this study suggest that giardiasis in otherwise healthy children does not cause marked structural damage to the small bowel mucosa, as seen by the light microscope. However, some form of damage to the brush border does occur frequently, as evidenced by a depression of brush-border enzymes. This damage most likely contributes to the diarrhea and also to the carbohydrate intolerance in these patients.
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PMID:Intestinal disaccharidase and alkaline phosphatase activity in giardiasis. 642 May 34

Unsuspected bacterial contamination of the small intestine was indicated by breath hydrogen testing in nine patients aged 2 to 34 months during physical examinations for chronic diarrhea and abdominal pain. Elevated bacterial counts of questionable significance were found in duodenal aspirates before and after antibiotic treatment. There was no evidence of bile salt deconjugation or structural changes in the small intestine by light or electron microscopy. This may indicate that the site of colonization is distal to the biopsy site. Breath testing indicated lactose malabsorption in all patients, and four of five patients tested also malabsorbed sucrose. Duodenal disaccharidase levels in all patients were within the normal ranges, but in eight patients the lactase-sucrase ratio was greatly elevated (0.80 +/- 0.36; normal less than 0.45). Dietary restriction alone did not cause complete cessation of symptoms, whereas all patients responded dramatically to oral antibiotic therapy. When patients were well, the lactase-sucrase ratio had returned to normal in those tested, and all nine had normal lactose and lactulose breath hydrogen tests. Unsuspected bacterial contamination of the small intestine, which is easily detected using the breath hydrogen test, may be more commonly associated with chronic diarrhea in children than has been previously realized. In such cases, therapy should be directed at removing the contamination.
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PMID:Bacterial contamination of the small intestine as an important cause of chronic diarrhea and abdominal pain: diagnosis by breath hydrogen test. 643 89

The pathogenesis of diarrhea caused by rotavirus infection was studied in miniature swine piglets. The animals were inoculated orally with 2 X 10(7) plaque-forming units of porcine rotavirus (OSU strain). During the height of diarrhea, intestinal function was investigated by in vivo perfusion of a 30-cm segment of proximal jejunum and a 30-cm segment of distal ileum. Absorption of Na+ and water decreased and 3-O-methylglucose transport was markedly reduced, P less than 0.01 compared to control animals. Mucosal lactase and sucrase levels were depressed in both the jejunum and ileum, P less than 0.001. Na+,K+-ATPase activity was significantly depressed only in the ileum, P less than 0.001. These changes were associated with a marked reduction in villous height, suggesting that the diarrhea could be an osmotic diarrhea due to nutrient (carbohydrate) malabsorption. Fresh stool samples were obtained and analyzed immediately for NA+,K+, osmolarity, glucose, and lactose; the osmotic gap was also determined. Stool osmolarity continually increased from 248 +/- 20 mosm/liter prior to inoculation to 348 +/- 20 mosm/liter at 75 +/- 1 hr postinoculation (P less than 0.005); the majority of the fecal osmotic gap could be accounted for by the amount of lactose present in the stools. Stool sodium increased from 34 +/- 6 mM prior to inoculation to a maximum of 65 +/- 4 mM at 53 +/- 1 hr postinoculation, P less than 0.001. There was no significant change in potassium concentration.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Pathogenesis of rotavirus-induced diarrhea. Preliminary studies in miniature swine piglet. 648 82

A naturally occurring enteropathy was identified in Irish setter dogs and wheat-sensitivity was demonstrated in a litter bred from two of the affected animals. The morphological and biochemical features of this enteropathy are described and compared to coeliac disease in man. Affected animals comprised 10 dogs that presented with poor weight gain or weight loss, with or without diarrhoea. Exocrine pancreatic function was normal and culture of duodenal juice demonstrated no marked bacterial overgrowth. Serum vitamin B12 concentrations were unaltered, but in some cases low serum and erythrocyte folate concentrations and reduced xylose absorption provided indirect evidence for proximal small intestinal disease. Examination of peroral jejunal biopsies revealed patchy morphological changes within individual animals, comprising predominantly partial, but in one case subtotal, villous atrophy. Brush border enzymes were selectively altered: the specific activities of alkaline phosphatase, leucyl-2-naphthylamidase and of zinc-resistant alpha-glucosidase were reduced by approximately 40 per cent, while activities of maltase, sucrase, lactase and gamma-glutamyl transferase were unaltered. Activity of a lysosomal enzyme was increased and there was evidence for enhanced lysosomal fragility. The activity of malate dehydrogenase, with a dual mitochondrial and cytoplasmic localisation, was decreased but there were no changes in the activities of marker enzymes for basal-lateral membranes, endoplasmic reticulum or peroxisomes. These findings, particularly the specific biochemical abnormalities, were comparable to those in partially treated coeliac disease in man; however, a specific role for wheat in the pathogenesis of the disease has yet to be defined.
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PMID:Morphological and biochemical studies of a naturally occurring enteropathy in the Irish setter dog: a comparison with coeliac disease in man. 652 28

H2 breath analysis was carried out to determine the prevalence of lactase deficiency in different tribes of the South African black population. Lactase deficiency was common (78%), despite the fact that 2 of the largest tribes (Zulu and Xhosa) are cattle herders and milk drinkers. This apparent anomaly is due to the consumption of a traditional fermented buttermilk (amasi) which has a low lactose content, instead of milk. The most important reason for lactase deficiency, however, is that the South African blacks originated in the West and Central African zone of nonmilking and took up dairying and milk use fairly recently. Thus they have not had enough time for genetic selection for lactase deficiency through life. Experience in Africa has shown that introducing skimmed milk causes diarrhea which may have catastrophic results in terms of mortality and morbidity. The implications inherent in this study are that it would be more prudent to supply milk to developing countries in the form of a fermented milk product such as buttermilk, prepared under traditional conditions and without refrigeration, since commercially prepared products do not have much less lactose and would also cause diarrhea in this population.
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PMID:Lactase deficiency in the South African black population. 665 Apr 48


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