The piezoelectricity of cyanoethylated hydroxyethylcellulose was investigated. Elastic, piezoelectric, and dielectric relaxations were observed at -80 ° to -60°C and 0 ° to 20°C at a frequency of 10Hz. The activation energy is about 9-15kcal/mol in the low temperature region and about 30-45kcal/mol at room temperature. These relaxations in the low temperature region may be caused by the motion of the cyanoethyl group and those at room temperature mostly by the motions of the main chain. Cyanoethylated hydroxyethylcellulose has a high piezoelectric strain constant (d25), which is the largest value among the cellulose derivatives and is almost the same as the value for polyvinylidene fluoride. The electromechanical coupling factor for cyanoethylated hydroxyethylcellulose was small.

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We report a case of malignant paraganglioma of the stomach. A gastric endoscopic examination on a 67-year-old female, performed for follow-up purposes, revealed an irregularly elevated lesion with a central ulcer on the lesser curvature of the lower body. The lesion showed characteristics of both an epithelial tumor and a submucosal tumor by endoscopy and radiography. The biopsy specimen suggested that the lesion was a malignant poorly differentiated tumor. On abdominal ultrasonography and computed tomography, several space occupying lesions were found in both lobes of the liver. Therefore, this case was diagnosed as having an advanced gastric cancer with liver metastases and underwent distal gastrectomy. Postoperatively, a final diagnosis of gastric paraganglioma was made by histological and immunohistochemical findings (positive for Grimelius, neuron specific enolase and other stains). These findings also revealed lymph node metastases. To date, only seven cases of gastric paraganglioma have been reported. Furthermore, two cases of malignant gastric paraganglioma have also been described in the literature. This is the first case of malignant gastric paraganglioma evaluated in detail by endoscopic and radiographic examinations. (Dig Endosc 1997 ; 9 : 60-63)