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To identify diffuse mucosal changes which may precede the development of colorectal cancer and a possible indicator for detecting high-risk populations, we immunohistochemically studied cell-cycle events in crypts of normal-appearing rectal mucosa of patients with colorectal adenoma and cancer using an in vitro labeling method with bromodeoxyuridine (BrdU). Biopsy specimens of endoscopically normal-appearing rectal mucosa were obtained during colonoscopy from 20 patients with colorectal adenocarcinoma, 20 with adenoma, and 15 without apparent colorectal diseases. The specimens were incubated with BrdU in vitro, and labeled S-phase cells were identified immunohistochemically using a monoclonal antibody to BrdU. Modification of the BrdU-labeling pattern in the normal appearing rectal mucosa, such as the presence of BrdU-labeled cells at the mucosal surface or in the upper one-fifth of the crypt column, was observed in 15 of the 20 patients with adenocarcinoma, 17 of the 20 patients with adenoma and 6 of the 15 controls. This upward shift in the frequency of proliferating cells in the crypt was significantly higher in the patients with colorectal adenoma and cancer than in the controls, and may be used to identify subjects at high risk for colorectal cancer.

Endoscopical segmental piecemeal tumorectomy (ESPT) for nodular elevation of colorectal tumor is advantageous in terms of minimizing both surgical invasion and postoperative burden to the patients. Nodular elevation of colorectal tumors is said to occur when the body of the tumor is adenomatous and the surface of the focal cancer grows more horizontally into the lumen than vertically. We report here four cases of nodular elevation of colorectal tumors which were each treated by different surgical procedures.

Mucus glycoprotein is one of the major components of gastric mucus which plays an important role in mucosal defensive mechanisms as a mucus-bicarbonate barrier. Analysis of the mucus glycoprotein synthesis is a useful tool for evaluating gastric mucosal defensive factors. UDP-galactosyltransferase (UDP-Gal-T) is one of the regulating enzymes for the synthesis of the mucus glycoprotein. In the present paper, we studied assay methods for UDP-Gal-T activity in rat gastric mucosa using radiolabeled UDP-galactose and two different kinds of acceptor proteins, namely ovomucoid and asialomucin, and analyzed effects of antisecretory agents on the UDP-Gal-T activity. We used crude supernatants of homogenized scrapings of the fundic part of rat stomach as an enzyme preparation and determined optimal conditions. In each acceptor, Mn2+ and the non-ionic detergent Triton X-100 were required for the enzyme activity. With each acceptor molecule, the type of glycosidic linkages of galactose was beta-type linkage. With asialomucin as an acceptor, UDP-Gal-T activities of rat gastric mucosa decreased after intraperitoneal administration of antisecretory agents, while change of the enzyme activity was not observed with ovomucoid as an acceptor.