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)
Although HemoQuant provides a precise measurement of fecal heme and its porphyrin degradation products, the test's performance characteristics in the detection of colorectal neoplasia are less satisfactory than those of Hemoccult II, a qualitative test for the presence of heme.
A prospective controlled study of the safety of various catheter dressing protocols was carried out in 168 patients receiving parenteral nutrition via an infraclavicular central venous catheter. Four protocols were compared: 36 patients received gauze dressings changed three times per week; 31 received OpSite dressings changed every 7th day (OpS-7), 32 received OpSite changed every 10th day (OpS-10), and 69 received OpSite changed twice weekly (OpS-ICU). Mean duration of parenteral nutrition was approximately 2 weeks and all groups were well matched except that OpS-ICU patients suffered more frequently from an acute illness. Catheter-related sepsis was identified by clinical signs of systemic sepsis, positive peripheral venous blood and catheter-tip cultures and/or defervescence of fever after catheter removal. Catheter-related sepsis rates were low in all groups: 1/36 for Gauze, 0/31 for OpS-7, 1/32 for OpS-10, and 2/69 for OpS-ICU. Septicemia attributable to causes apart from catheter sepsis occurred in two, two, three, and four patients, respectively. Bacterial colonization of skin beneath OpSite was no more common in the OpS-10 than in the other groups. Signs of inflammation at catheter insertion sites were common in all groups but did not relate closely to skin colonization. OpSite can be safely applied to central venous catheters inserted under strict aseptic conditions, even in patients with open septic drainage. Dressings can be left in place for 7 days with a margin of safety lasting to 10 days, thus saving on cost of materials and nursing time.
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