To evaluate the diagnostic yield of the procedure, mucosal-incision assisted biopsy (MIAB), for the histological diagnosis of gastric gastrointestinal stromal tumor (GIST), we performed a retrospective review of the 27 patients with suspected gastric GIST who underwent MIAB in our hospitals. Tissue samples obtained by MIAB were sufficient to make a histological diagnosis (diagnostic MIAB) in 23 out of the 27 patients, where the lesions had intraluminal growth patterns. Alternatively, the samples were insufficient (non-diagnostic MIAB) in remaining 4 patients, three of whom had gastric submucosal tumor with extraluminal growth patterns. Although endoscopic ultrasound and fine needle aspiration is the gold standard for obtaining tissue specimens for histological and cytological analysis of suspected gastric GISTs, MIAB can be used as an alternative method for obtaining biopsy specimens of lesions with an intraluminal growth pattern.

The preoperative use of endoscopic ultrasound was evaluated in 74 patients with confirmed gastric cancer. It was used in diagnosing the depth of invasion in the gastric wall, the infiltration to the adjacent organs, and the involvement of the perigastric lymph nodes. Results were compared with histological findings in resected specimens. Accuracy in staging gastric cancer using the T grade of the 1987 TNM system was 81-1% (60 of 74 patients MethodsBetween October 1986 and March 1990, we performed preoperative endoscopic ultrasound in 74 patients with a diagnosis of gastric cancer that had been confirmed by endoscopic biopsy specimen. There were 49 men and 25 women whose ages ranged from 17 to 85 years (mean 60 years). They underwent surgery after preoperative examinations including upper gastrointestinal series, endoscopy, endoscopic ultrasound, conventional transcutaneous ultrasound, and computed tomography. All the resected specimens, including lymph nodes, were examined histopathologically and results of the preoperative endoscopic ultrasound scanning were compared with both the intraoperative macroscopic findings and the pathology of the resected specimens. Echoendoscopes with radial sector scan transducers (GF-UM2, UM3, frequency 7 5 or 12 MHz) manufactured by Olympus (Tokyo, Japan) were used. The maximal penetration of the ultrasonic beam is 10 cm with 7 5 MHz and 3 cm with 12 MHz.To evaluate the gastric cancer, the echoendoscope was introduced into the stomach after premedication. The lesions were first observed endoscopically. Next the stomach was filled with deaerated water via the echoendoscope in sufficient quantity to allow us to see the lesion through the water occasionally. In addition the water filled balloon method'4 was used to confirm small lesions. Thereafter, we used the endoscopic ultrasound scanning technique to obtain an image of the lesion and of the normal gastric wall through the water. The entire procedure took about 20 minutes and there were no complications.

We investigated the binding characteristics of the endothelin (ET) receptor and the mechanism by which ET induces contraction of longitudinal smooth muscle cells of the guinea pig small intestine by using vasoactive intestinal contractor (VIC), a mouse variant of ET-2. A functional receptor for VIC was found to exist on longitudinal smooth muscle cells. These cells showed a similar binding of and contractile response to ET-1, ET-2, and ET-3. Inhibitors of both intracellular and extracellular Ca2+ movement attenuated the VIC-induced contraction of longitudinal smooth muscle cells. These results suggest that smooth muscle cells of the guinea pig small intestine express the ETB receptor that primarily mediates the contractile effect on smooth muscle cells. In addition, ET-induced contraction depends on intracellular as well as extracellular Ca2+.

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