Akira Hokama1, Masayoshi Nagahama2, Kazuto Kishimoto3, Jiro Fujita3. 1. Department of Endoscopy, University of the Ryukyus, Nishihara, Japan. 2. Department of Digestive and General Surgery, University of the Ryukyus, Nishihara, Japan. 3. Department of Infectious, Respiratory, and Digestive Medicine, University of the Ryukyus, Nishihara, Japan.