1. Department of Gastroenterology and Hepatology; Graduate School of Medicine, Hokkaido University; Hokkaido Japan
2. Hakodate City Hospital; Hokkaido Japan
3. Sapporo City General Hospital; Hokkaido Japan
4. Hokkaido Social Insurance Hospital; Hokkaido Japan
5. Sapporo Hokuyu Hospital; Hokkaido Japan
6. Tokyo Metropolitan Bokuto Hospital; Tokyo Japan
7. Department of Dermatology; Hokkaido University Graduate School of Medicine; Hokkaido Japan
8. Department of Gastroenterology and Hepatology; Tokyo Medical and Dental University; Tokyo Japan