The purpose of this study was to explore the relationship between the preoperative plasma D-dimer (DD) levels and the tumor pathology of colorectal cancer. The plasma DD levels were measured preoperatively in 108 patients with colorectal cancer, and then were correlated with the tumor pathology and stage. The diagnostic value of the DD levels for the tumor stage was then compared with that of the preoperative carcinoembryonic antigen (CEA) levels. The preoperative DD levels were higher in patients with either a large-sized tumor or a tumor showing deep wall penetration. Lymph-node metastasis, lymphatic invasion, hepatic metastasis, and peritoneal dissemination were all associated with higher DD levels. A stepwise increase in the median DD level was found with the tumor stage. The preoperative DD levels also significantly correlated with CEA levels. When a cutoff value of 0.6 microg/ml was used in the DD assay, the sensitivity and specificity for Dukes C or D cancer were 67.2% and 64.0%, and those for Dukes D cancer were 91.3% and 57.6%, respectively. Although the DD assay was less specific, its diagnostic value in the preoperative staging of colorectal cancer was comparable to that of the CEA assay. The measurement of the preoperative DD level is thus considered to be useful for the preoperative staging of colorectal cancer.

The tight junction of pancreatic exocrine cells is thought to regulate paracellular permeability, and is a possible reflux route of pancreatic juice into the blood flow. Morphological changes in the tight junction of canine pancreatic acinar cells following intraductal hypertension and secretin stimulation were morphometrically analyzed to obtain evidence of the control of the paracellular reflux. Pancreatic tissues obtained from 25 dogs after intraductal hypertension, 3 dogs after secretin stimulation, and 5 control dogs were studied. Intraductal pressure was either 20 cmH2O, 30 cmH2O, or 40 cmH2O. Freeze fracture replicas of these pancreatic tissues were observed by electron microscopy. Tight junctions were classified into six morphometric types. Reticular type, parallel type, and mixed type comprised the common types predominantly found in all groups, and three special types were found, infrequently, only after intraductal hypertension. The percentages of the common types were significantly different between the groups. The areas of the tight junctions, and other morphometric parameters, were significantly less after 20 cmH2O intraductal hypertension and secretin stimulation than in the controls. However, these findings after 30 cmH2O or 40 cmH2O intraductal hypertension did not differ from those in the controls. The areas of the three special types of tight junctions were larger than those of the common types. These results suggest that the tight junction of pancreatic exocrine cells is a morphologically dynamic structure that is altered by the extent of intraductal hypertension, and support the hypothesis that paracellular permeability is the mechanism of the reflux of pancreatic juice.

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