Michio Miyata

Distribution of Transforming Growth Factor‐β and Its Receptors in Gastric Carcinoma Tissue

The distribution of the three mammalian isoforms of transforming growth factor (TGF)‐β (TGF‐β1,‐β2, and ‐β3) as well as their signaling receptors, TGF‐β type I and type II receptors (TβR‐I and TβR‐II, respectively), in gastric carcinoma tissue was examined by immunohistochemistry using specific antibodies. Tissue specimens were obtained from 25 cases of gastric carcinoma, which were classified into two groups according to Laurens classification, i.e. 15 cases of diffuse carcinoma and 10 cases of intestinal carcinoma. In normal gastric mucosa apart from carcinoma nests, all of TGF‐β1, ‐β2, ‐β3, TβR‐I and TβR‐II were clearly demonstrated in fundic glands. In sharp contrast, none of them was detectable in surface mucous cells. In carcinoma cells, strong staining for TGF‐β1, ‐β2 and β3 was obtained only in diffuse‐type carcinoma. In particular, carcinoma cells scattered as single cells or small nests had a tendency to show strong staining for TGF‐βs. The receptors tended to be distributed concomitantly with the ligands, and diffuse‐type carcinoma showed stronger receptor staining than intestinal‐type carcinoma. In cancer stroma, TGF‐βs and receptors were detected in both diffuse and intestinal types, but the area with positive staining was wider and more dispersed in diffuse‐type carcinoma than in intestinal carcinoma. These results suggest that TGF‐β may contribute in part to the variety of histogenesis and mode of progression of gastric carcinoma.

EFFECT OF OBSTRUCTIVE JAUNDICE ON AMYLASE SECRETION IN RAT PANCREATIC ACINI

SummaryThe effect of obstructive jaundice on pancreatic amylase secretion was studied in isolated pancreatic acini prepared from bile duct ligated rats (7 days postoperatively), sham operated rats being used as control. Obstructive jaundice caused increase in pancreatic wet weight, pancreatic protein content and pancreatic amylase content by 27.9%, 40.1% and 33.2%, respectively. In acini prepared from obstructive jaundice group, compared with acini from sham operation group, responsiveness to cholecystokinin (CCK) and carbachol was decreased when amylase release was expressed as the percentage of total amylase activity initially present in acini. However, sensitivity to both secretagogues was unchanged when expressed as the percentage of maximally stimulated amylase release. The dose-response curves to Ca2+ ionophore for amylase release were similarly shaped in both groups. These results suggested that a pancreatico-trophic effect, compared with altered responsiveness of pancreatic acini, should play a major role in hypersecretion in obstructive jaundice.