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Query: EC:3.2.1.26 (invertase)
 4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

Food was given to pigs before weaning to determine whether a hypersensitive response to dietary antigen might be a predisposing factor to postweaning diarrhea. Small amounts of food increased the severity and accelerated the onset of postweaning diarrhea. Postweaning diarrhea was dependent on the presence within the diet of antigenic material (bovine casein). A weaning diet, containing little antigenic material (hydrolyzed casein), had less effect on sucrase concentration in intestinal brush borders than did diets rich in antigens (native casein). Seemingly, immune-mediated intestinal damage may predispose the pig to postweaning diarrhea.
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PMID:The importance of dietary antigen in the cause of postweaning diarrhea in pigs. 649 29

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

Mucin secretion was examined in three functional models relevant to human disease, using rat small intestinal rings or in situ loops, [3H]glucosamine precursor labelling, gel chromatography and a specific radioimmunoassay for mucin. As a model for acute bacterial secretory diarrhoea, tissues were exposed to cholera toxin for up to 4 h. Both stored and newly synthesized radioactive glycoproteins were secreted in amounts twofold to threefold above control levels. Immunoreactive mucin secretion increased fivefold to eightfold. Other agents known to raise cAMP levels did not stimulate mucin secretion, suggesting that cholera may release mucin by a non-cAMP-dependent mechanism. Sepharose 2B chromatography indicated that secreted mucin was smaller in size than intracellular mucin and had compositional differences suggestive of 'immaturity' or protein contamination. In chronically (seven days) reserpinized rats, used as a model of glycoprotein abnormalities relevant to cystic fibrosis, mucin secretion increased twofold to threefold, but the most prominent abnormality was a marked increase in [3H]glucosamine incorporation into all tissue glycoproteins. On purification, the intracellular mucin of reserpine-treated rats had the same composition as mucin from control rats, but the former was smaller in size and had a higher specific radioactivity. Mucin hypersecretion in reserpinized rats may therefore be secondary to a primary and chronic hyperstimulation of mucin biosynthesis. A model of intestinal 'anaphylaxis' or immune-mediated diarrhoea was created in Hooded Lister rats by immunizing with egg albumin (10 micrograms) and challenging with the same antigen in intestinal loops 14 days later. After 4 h, total protein, DNA and brush border sucrase were increased in the lumen. Enhancement of mucin secretion did not occur, however, and therefore does not seem to be a particular feature of the pathophysiology of this model.
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PMID:Acute and chronic models for hypersecretion of intestinal mucin. 656 39

The development of glucoamylase activity was compared to that of disaccharidase in the small intestinal mucosa of infants and children. By the age of one month, infants have glucoamylase and disaccharidase levels comparable to those of young adults, indicating that young infants may be able to digest and absorb starches. In infants and children with varying degrees of mucosal injury of the small intestine, the activities of glucoamylase decreased progressively with increasing severity of the villus atrophy. However, the reduction of lactase, palatinase, and sucrase activities was more severe than the loss of activities of glucoamylase and maltase. Thus, children and infants may tolerate polymers of glucose better than disaccharides when they have mucosal injury associated with prolonged diarrhea.
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PMID:Glucoamylase and disaccharidase activities in normal subjects and in patients with mucosal injury of the small intestine. 677 72

Thirty infants with intractable diarrhea of infancy (IDI) underwent small bowel biopsies in order to determine the extent and duration of small intestinal mucosal injury. The onset of the persistent diarrhea occurred prior to 3 months of age and continued for an average of 48 days prior to investigation. In 18 cases, no associated entities were found. Mucosal injury was invariably found in all 30 infants: grade IV injury in 11, grade III in eight, grade II in nine, and grade I atrophy in one. Disaccharidase activities were diminished and corresponded to the degree of atrophy. Lactase activity was diminished to a greater extent than sucrase and maltase. Significant, persistent mucosal injury existed for an average of six months in 16 of the 23 (70%) repeat biopsies. All infants were given an elemental diet (ED). Twelve of the 30 infants required parenteral nutrition (PN). These infants were gradually advanced to an oral elemental diet and maintained on this diet until histologic findings and disaccharidase levels were normal. Eighteen infants were fed and maintained on an elemental diet by mouth from time of admission until normal histologic findings and disaccharidases were found. No mortality occurred during management and follow-up. Twenty-two of the 28 infants in whom follow-up growth data were available excelled in weight and height velocity. The data suggest that prolonged injury to the small intestinal mucosa is a common finding in many cases of intractable diarrhea of infancy. Elemental diets should be started early in the course of protracted diarrhea in young infants, and may need to be continued for several months since histologic and enzymatic changes of the small intestine may persist for extended periods.
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PMID:Extent and duration of small intestinal mucosal injury in intractable diarrhea of infancy. 677 76

There are at least 20 rare autosomal recessive disorders that are excessively common in Finland of which congenital lactase deficiency is one. During the last 17 years we have found 16 cases. In each case the mother noted watery diarrhoea, generally after the first feed of breast milk, and at the latest, by age 10 days. The lactose malabsorption was verified at a mean age of 36 (range 3-90) days, by which time the infants were dehydrated and 15 of them weighed less than at birth (mean weight for age was -2.8 SDs). On a lactose-free elimination diet (a group of 6 on Nutramigen and a group of 10 on soy-based formula) the children caught up in growth. One infant in each group showed allergic symptoms. While the infants were being breast fed their faeces contained 20 to 80 g/l lactose. In 24 peroral lactose tolerance tests, the greatest rise in blood glucose concentration was 0.8 mmol/l. Only 2 patients showed abnormal absorption when tested within a week of lactose elimination, and in each absorption tests became normal during the elimination period. Slight to partial villous atrophy of the jejunum was present in 4 early specimens, but in later ones the mean villous height was normal. The mean height of the epithelial cells was reduced and there were fewer intraepithelial lymphocytes in patients. The lactase activities in jejunal biopsy specimens were lower than in most patients with acquired lactase deficiency, with some overlap. The maltase and sucrase activities were normal.
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PMID:Congenital lactase deficiency. A clinical study on 16 patients. 684 26

Investigations by scanning electron microscopy into changes of surface morphology of small bowel mucosa in children with chronic nonspecific diarrhea are reported. The study population comprised 56 patients, ranging in age from 5 months to 7 years; 65% were between 10 and 28 months old, and 64% of the patients were boys. The major findings were: microorganisms on the mucosal surface; excessive extrusion of cell cytoplasm and of enterocytes (cell shedding); presence of excessive mucus on the mucosal surface; damage to the brush border; and partial villous atrophy. The latter lesion was found in only four patients. All these changes are considered pathologic and, for the most part, are presumed to be due to the presence of antigens, in particular, microorganisms. A depression of disaccharidase activities was encountered in 64% of the patients, but prevalence was without regard to age. Most common was a combined depression of lactase, sucrase, and maltase, as well as an isolated depression of lactase. The possibility has to be considered that enteroadherent microorganisms which are usually not considered pathogenic, and microorganisms such as Mycoplasma, may emerge as intestinal pathogens in susceptible children. It is feasible that genetic traits of the host and environmental factors facilitate adherence and colonization of the small bowel mucosa which, in turn, produces chronic diarrhea. Further studies are needed to confirm the preliminary information contained in this report.
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PMID:Chronic nonspecific diarrhea in children: investigation of the surface morphology of small bowel mucosa utilizing the scanning electron microscope. 688 51

An oral sucrose tolerance test was performed in a group of 103 children, aged between 3 months and 15 years because of episodic diarrhea and/or abdominal pains. Sucrose malabsorption defined as an abnormal increase in expired hydrogen, was found in only 3 children who suffered from congenital sucrase-isomaltase deficiency. This 1% incidence of sucrose malabsorption was lower than the incidence of lactose malabsorption found in this group (33%). Mean rise in blood glucose during the sucrose test was higher (3.4 +/- 1.4 vs. 2.4 +/- 1.2 mmol/l, p less than 0.0001) and the occurrence of false flat blood glucose curves was lower (3% vs. 12.8%, p less than 0.05) than during the lactose test. These findings are consistent with the higher sucrase activity in the small bowel mucosa compared to lactase. In contrast to the lactose tolerance test, sucrose tolerance test should not be used as a screening procedure for secondary disaccharidase deficiency in children.
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PMID:Diagnostic value of sucrose tolerance test in children evaluated by breath hydrogen measurement. 736 16

The 4-5 days-old NMRI strain infant mice were orally inoculated with EB rotavirus (serotype 3). The intestinal disaccharidases activity was studied separately in three segments of the small intestine i.e. duodenum, jejunum and ileum on day 1 to 7 post inoculation (p.i.). The severity of EB rotavirus infection correlated with a significant decrease of small intestinal lactase, maltase and sucrase on day 3 p.i. The level of maltase after the initial decline increased in all the three segments of small intestine of infected mice. However, the lactase activity remained suppressed for a relatively longer period in ileum of infected mice than in controls. These enzymes began to approach to normal value by day 5 p.i., but in ileum, lactase activity continued to be severely depressed even on day 7 p.i. Rotavirus was consistently detected in intestinal contents by ELISA on days 1 to 7 p.i. The infected mice showed a significant increase in rotavirus (serotype 3)-specific serum IgG and IgM antibody level during the declining (days 5-7 p.i.) phase of infection. Diarrhoea was noted up to day 6 p.i. The protracted suppression of the lactase activity in ileum in comparison to duodenum and jejunum showed a differential tropism of EB rotavirus (serotype 3) strain to the small intestine of homologous murine model.
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PMID:Differential tropism of EB rotavirus (serotype 3) to small intestine of homologous murine model. 772 1


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