Gene/Protein Disease Symptom Drug Enzyme Compound
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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)

Expression of brush border hydrolases can reflect the state of differentiation of an epithelium. To determine if expression of these enzymes is disordered in patients with neoplastic or hyperplastic lesions, the activities of alkaline phosphatase, maltase, and dipeptidyl peptidase IV were measured spectrophotometrically in colonoscopic biopsies from the proximal and distal colon and rectum in 50 controls, 17 patients with large bowel adenomas, 29 with carcinoma, and 9 with hyperplastic polyps. In normal controls, a descending cecorectal gradient of alkaline phosphatase activities and an ascending gradient of maltase activities were seen (P < 0.001). Though regional patterns of expression were generally preserved in disease groups, there were significant differences of activities across patient groups for alkaline phosphatase (greater in cancer, adenoma, and hyperplastic groups than in normals; P < 0.05) and for dipeptidyl peptidase IV (greater in hyperplastic polyp group than normals, greater in adenoma than cancer group; P < 0.05). Compared with normal controls, abnormalities of site-specific activities were confined to the rectum in patients with adenoma (maltase decreased, P = 0.02; dipeptidyl peptidase IV increased, P < 0.01) or with carcinoma (alkaline phosphatase increased, P = 0.03) but dipeptidyl peptidase IV activities were increased in all regions in bowels bearing hyperplastic polyps (P < 0.01). These data suggest that neoplastic and hyperplastic lesions, while focal in nature, occur in large bowel epithelium, which is diffusely abnormal in terms of its expression of these enzymes.
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PMID:Neoplasia and hyperplasia of large bowel: focal lesions in an abnormal epithelium. 135 42

Previous studies have suggested that abnormal expression of enzymes characteristic of the intestinal brush border might accompany colonic neoplasia and possibly facilitate identification of epithelium at risk of malignancy. To test this possibility, the distribution of the brush border enzymes sucrase-isomaltase (SIM), maltase-glucoamylase (MGA), aminopeptidase-N (APN) and diamino-peptidylpeptidase-IV (DPPIV) were studied by the immunoperoxidase method in biopsies from the rectum and caecum of normal subjects, and neoplastic and non-neoplastic tissues from patients with adenoma or cancer. Brush border enzymes were detected by immunohistochemistry more frequently in the caecum than the rectum (P less than 0.05) of normal subjects. Diamino-peptidylpeptidase-IV and APN were present in highest concentration at the brush border of the most mature colonocytes on the luminal surface with less staining in the crypt, whereas SIM and MGA staining of the brush border was as prominent on crypt cells as surface cells. While all cancers expressed at least one enzyme, there was heterogeneity of staining within tumours and a tendency to lose polarity of enzyme expression in cells, sometimes with dense staining of the cytoplasm. Distally situated adenomas uncommonly expressed a brush border enzyme (25%) and the only enzyme expressed in them was SIM. These finding indicate that these brush border enzymes are not exclusively expressed in the small intestine; DPPIV and APN are markers of the normal mature colonocyte and should prove useful as markers of differentiation. However, the change associated with neoplasia would not appear to be of clinically predictive value.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Brush border hydrolases in normal and neoplastic colonic epithelium. 151 57