1. 2nd Department of Internal Medicine, Osaka Medical College, 2-7 Daigakuchou, Takatsukishi, Osaka 569-8686, Japan
2. Division of Endoscopy, Shizuoka Cancer Center, Shizuoka, Japan
3. Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
4. Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan
5. 2nd Department of Internal Medicine, Osaka Medical College, Osaka, Japan