1. Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
2. Department of Gastroenterology, Osaka General Medical Center, Osaka, Japan
3. Department of Gastroenterology, Osaka National Hospital, National Hospital Organization, Osaka, Japan
4. Department of Gastroenterology, Toyonaka Municipal Hospital, Toyonaka, Japan
5. Department of Gastroenterology, Osaka Hospital, Japan Community Health Care Organization, Osaka, Japan