1. Department of Gastroenterology and Hepatology, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
2. Shimonoseki Kosei Hospital, Yamaguchi, Japan
3. Tohoku Rosai Hospital, Miyagi, Japan
4. Akita City Hospital, Akita, Japan
5. St Mary's Hospital, Fukuoka, Japan
6. Nanpuh Hospital, Kagoshima, Japan
7. Otsuka Pharmaceutical Co, Ltd., Tokyo, Japan
8. Social Insurance Alliance Shimonoseki Kosei Hospital, Yamaguchi, Japan