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Target Concepts:
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Query: EC:3.2.1.20 (
alpha-glucosidase
)
4,237
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Reactive oxygen species have been found to be responsible for the tissue injury caused in experimental pyelonephritis in mice. The extent of lipid peroxidation (as assayed by malondialdehyde formation) was found to be increased significantly (p less than .001) in the infected group as compared to the normal mice. Superoxide dismutase and catalase (oxygen free radical scavengers) showed a significant decrease (p less than .001) in the extent of lipid peroxidation even in the presence of infection. Dimethyl sulfoxide, a hydroxyl ion scavenger, was however found to be effective only at 4 and 7 days postinfection (p less than .001). Allopurinol, an inhibitor of xanthine oxidase, did not significantly (p greater than .05) inhibit the formation of lipid peroxides, even upto 7 days postinfection. There was a significant decrease (p less than .05) in the activities of renal brush border membrane enzymes used as markers of renal tissue damage (i.e. alkaline phosphatase, leucine amino-
peptidase
and gamma-glutamyl transpeptidase) in the infected group as compared to the normal group. In the presence of superoxide dismutase, dimethylsulfoxide and catalase except allopurinol, the activities of all the enzymes but
maltase
were found to be increased significantly (p less than .05) as compared to the infected group. There was a significant increase (p less than .01) in the bacterial count in the presence of superoxide dismutase and DMSO in infected mice as compared to the infected control mice. However, no significant difference was observed in the catalase and allopurinol treated groups.
...
PMID:Effect of various oxygen free radical scavengers in preventing tissue injury caused by Escherichia coli in pyelonephritic mice. 305 56
Animal experimentation with total parenteral nutrition (TPN) has revealed the occurrence of atrophy of the intestinal mucosa and decreased enzyme activities of the brush border, notably the disaccharidases. These findings have heretofore not been confirmed in human investigation. We performed endoscopic biopsies in the third part of the duodenum in 7 adults before TPN, after 21 days of TPN, and after a progressive oral refeeding. We noted a clear-cut decrease of major enzyme activities during TPN (sucrase,
maltase
, lactase, glucoamylase, acid aminopeptidase, dipeptidyl
peptidase
) without any morphologic modifications as observed with standard histology. Electron microscopy showed a slight but significant decrease in the height of microvilli. The decreased enzyme activities were rapidly restored after oral refeeding. Thus, the functional consequences of the modifications observed during medium-term TPN in adults are probably limited.
...
PMID:Decreased brush border hydrolase activities without gross morphologic changes in human intestinal mucosa after prolonged total parenteral nutrition of adults. 307 17
A wide variety of enzymes actualizing membrane hydrolysis of nutrients and their distribution in the gastro-intestinal tract were characterized in one-day old and adult rats and rabbits. The comparison of enzymatic activities of various animal species suggests that some enzymes are responsible for the adaptation to milk diet (lactase), others--to definitive nutrition (invertase,
maltase
). A number of enzymes (
peptidase
, alkaline phosphatase) do not depend on the type of nutrition. High activity of some hydrolases in the colon has been demonstrated confirming the A. M. Ugolev hypothesis of its digestive functions in the early ontogenesis.
...
PMID:[Hydrolases of the digestive organs during ontogenesis]. 308 39
Oral feeding of DL-difluoromethyl ornithine (DFMO) (2% in water ad libitum) for 14 days has no detectable effect on the small intestine of adult rats. Similar feeding of DFMO to weanling rat pups caused diarrhea in three to four days accompanied by a decrease in food consumption and body weight compared to age-matched controls. Significant decreases in small intestinal mucosal weight, total protein, DNA, enterokinase, leucine amino
peptidase
, sucrase, and
maltase
contents were observed in the DFMO-treated group four days after treatment. Extending the treatment to seven days led to a more severe reduction in these parameters. Villous atrophy of the mucosa was demonstrable by light microscopy and morphometric measurements. The mucosa of the DFMO-treated rat pups showed a reduction in total thickness and villous height but no change in crypt depth. A significant reduction in villus-crypt ratio was also seen. Changes in small intestinal mucosal parameters were not due to a decrease in food intake since pair-fed, age-matched rat pups showed no biochemical changes compared to control pups. DFMO-treated weanling rats showed less than 5% of ornithine decarboxylase (ODC) activity when compared to age-matched control animals. The effects observed on the small intestinal mucosa are presumably due to inhibition of ornithine decarboxylase activities by DFMO which prevents the proliferation, regeneration, and maturation of epithelial cells. The relative insensitivity of the adult rat small intestine to DFMO treatment suggests a lesser dependence of its intestinal mucosa to ODC activities.
...
PMID:Effect of difluoromethyl ornithine (DFMO) on small intestine of adult and weanling rats. 311 4
The uptake of nutrients and activities of membrane enzymes in the kidney were investigated using renal brush border membrane (BBM) vesicles in acute pyelonephritis in rats. A significant decrease (P less than 0.001) in the uptake of D-glucose and L-phenylalanine was observed in both the unobstructed right and obstructed left kidney, while there was a significant increase (P less than 0.001) in the uptake of L-alanine in the left kidney of pyelonephritic rats, demonstrating disturbances in the reabsorption of the glucose and aminoacids in the kidneys. Vmax of alkaline phosphatase, leucine-amino-
peptidase
and
maltase
was found to be decreased in the left kidney, suggesting that there was a reduction in the active enzyme molecule number. Km of alkaline phosphatase and leucine-aminopeptidase remained unchanged, while km of
maltase
decreased in both the right and left kidneys. An increase in the Vmax of alkaline phosphatase and leucine-aminopeptidase and substrate affinity of the
maltase
in the right kidney demonstrated a compensatory phenomenon for the malfunctioning of the left kidney. This is the first report demonstrating alterations in reabsorption of nutrients and BBM enzymes in experimental pyelonephritis.
...
PMID:Pyelonephritis alters the reabsorption of nutrients and brush border membrane enzymes of rat kidney. 390 22
1. A method for the preparation of brush border from rabbit kidneys is described. Contamination by other organelles was checked by electron microscopy and by the assay of marker enzymes and was low. 2. Seven enzymes, all hydrolases, were substantially enriched in the brush-border preparation and are considered to be primarily located in this structure. They are: alkaline phosphatase,
maltase
, trehalase, aminopeptidase A, aminopeptidase M, gamma-glutamyl transpeptidase and a neutral
peptidase
assayed by its ability to hydrolyse [(125)I]iodoinsulin B chain. 3. Adenosine triphosphatases were also present in the preparation, but showed lower enrichments. 4. Alkaline phosphatase was the most active phosphatase present in the preparation. The weak hydrolysis of AMP may well have been due to this enzyme rather than a specific 5'-nucleotidase. 5. The two disaccharidases in brush border were distinguished by the relative heat-stability of trehalase compared with that of
maltase
. 6. The individuality of the four peptidases was established by several means. The neutral
peptidase
and aminopeptidase M, both of which can attack insulin B chain, differed not only in response to inhibitors and activators but also in the inhibitory effect of a guinea-pig antiserum raised to rabbit aminopeptidase M. This antiserum inhibited both the purified and the brush-border activities of aminopeptidase M. The neutral
peptidase
and gamma-glutamyl transpeptidase were unaffected but aminopeptidase A was weakly inhibited. The characteristic responses to Ca(2+) and serine with borate served to distinguish aminopeptidase A and gamma-glutamyl transpeptidase from other peptidases. 7. No dipeptidases, tripeptidases or carboxypeptidases were identified as brush-border enzymes. 8. Incubation of brush border with papain released almost all the aminopeptidase M activity but only about half the activities of
maltase
, gamma-glutamyl transpeptidase and aminopeptidase A. No release of alkaline phosphatase, trehalase or the neutral
peptidase
was observed.
...
PMID:Studies on the enzymology of purified preparations of brush border from rabbit kidney. 414 72
Human lymphocytes were isolated from defibrinated blood by Ficoll-Hypaque centrifugation with erythrocyte hypotonic lysis. Homogenates of mixed lymphocytes were subjected to analytical subcellular fractionation by sucrose gradient centrifugation in a Beaufay automatic zonal rotor. The principal organelles were characterized by their marker enzymes: cytosol (lactate dehydrogenase), plasma membrane (5'-nucleotidase), endoplasmic reticulum (neutral
alpha-glucosidase
), mitochondria (malate dehydrogenase), lysosomes (N-acetyl-beta-glucosaminidase), peroxisomes (catalase). gamma-Glutamyl transferase was exclusively localized to the plasma membrane. Leucine amino-
peptidase
, especially when assayed in the presence of Co2+, was also partially localized to the plasma membrane. Experiments with diazotized sulphanilic acid, a non-permeant enzyme inhibitor, showed that these plasma membrane enzymes are present on the cell surface. No detectable alkaline phosphatase was found in the lymphocytes. Acid phosphatase and beta-glucuronidase were localized to lysosomes and there was some evidence for lysosomal heterogeneity. Leucine amino
peptidase
, optimal at pH 8.0, showed a partial localization to intracellular vesicles, possibly lysosomes, especially when assayed in the presence of EDTA. These studies provide a technique for determining the intracellular distribution of hitherto unassigned lymphocyte constituents and serve as a basis for investigating the cell pathology of lymphocytic disorders.
...
PMID:Enzyme analysis and subcellular fractionation of human peripheral blood lymphocytes with special reference to the localization of putative plasma membrane enzymes. 614 55
Circulating non-T lymphocytes had higher activities of 5'nucleotidase (plasma membrane), neutral
alpha-glucosidase
(endoplasmic reticulum) and basal leucine amino-
peptidase
than did T lymphocytes. Activities of catalase (peroxisomes), malate dehydrogenase (mitochondria), lactate dehydrogenase (cytosol) and N-acetyl-beta-glucosaminidase, beta-glucuronidase and acid phosphatase (lysosomes), were similar in the lymphocyte subfractions. Lymphocyte 5'nucleotidase (plasma membrane) in patients with common variable hypogammaglobulinaemia is much lower than normal. However, the decrease is less marked in X-linked hypogammaglobulinaemia, chronic lymphatic leukaemia or protein loosing enteropathy or in lymphocytes isolated from cord blood. Cells from patients with nephrotic syndrome had normal levels of 5'nucleotidase. Other plasma membrane marker enzymes (gamma-glutamyl transferase, leucine amino-
peptidase
) were normal in lymphocytes from patients with common variable hypogammaglobulinaemia. There is a selective reduction of mitochondrial (malate dehydrogenase) and cytosolic (lactate dehydrogenase) enzymes, with normal activities of lysosomal, peroxisomal and endoplasmic reticulum enzymes, in patients with common variable hypogammaglobulinaemia. The lymphocyte subcellular organelles in normal subjects and patients with common variable hypogammaglobulinaemia have similar properties on sucrose density gradient centrifugation. It is suggested that lymphocytes from patients with common variable hypogammaglobulinaemia show a specific enzymopathy and that this is not simply a reflection of cellular immaturity.
...
PMID:Lymphocyte enzyme activities in immunodeficiency syndromes with particular reference to common variable hypogammaglobulinaemia. 630 45
The subcellular biochemical features of a naturally occurring enteropathy in the dog associated with bacterial overgrowth have been examined. Affected animals comprised a group of 10 German Shepherd dogs with raised serum folate and reduced vitamin B12 concentrations, mild steatorrhoea, reduced xylose absorption, and normal exocrine pancreatic function. Culture of duodenal juice showed bacterial overgrowth with mixed flora, most frequently including enterococci and Escherichia coli. Examination of peroral jejunal biopsies revealed predominantly minimal histological but distinct biochemical abnormalities in the mucosa. The specific activity of alkaline phosphatase was decreased, isopycnic density gradient centrifugation showing a marked loss particularly of the brush border component of enzyme activity. In contrast, gamma-glutamyl transferase activity was enhanced in brush border fragments of slightly increased modal density, but there were no changes in the activities of the carbohydrases, zinc-resistant
alpha-glucosidase
,
maltase
, sucrase, and lactase or of the
peptidase
, leucyl-2-naphthylamidase. Activities of lysosomal enzymes were increased and there was evidence for enhanced lysosomal fragility and mitochondrial disruption. The activities and density gradient distributions of marker enzymes for basal-lateral membranes, endoplasmic reticulum and peroxisomes were essentially unaltered. These findings show that bacterial colonisation of the proximal small intestine may be associated with specific alterations in microvillus membrane proteins and provide biochemical evidence for intracellular damage to the enterocytes.
...
PMID:Biochemical changes in the jejunal mucosa of dogs with a naturally occurring enteropathy associated with bacterial overgrowth. 674 19
Administration of a single oral dose of dieldrin (20 mg/kg body wt.) to rhesus monkeys considerably elevated the uptake of glucose and the activities of brush border sucrase, lactase,
maltase
and alkaline phosphatase in intestine compared to control animals. Leucine uptake and leucine amino
peptidase
activity was significantly depressed in pesticide-treated animals. Kinetic studies with brush border sucrase revealed that augmentation of enzyme activity in pesticide-fed animals was due to an increase in the disaccharidase content.
...
PMID:Acute dieldrin toxicity: effect on the uptake of glucose and leucine and on brush border enzymes in monkey intestine. 679 50
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