1. Department of Gastroenterology and Hepatology, Takamatsu Red Cross Hospital, 4-1-3 Ban-cho, Takamatsu 760-0017, Japan
2. Department of Gastroenterology and Neurology, Kagawa University Faculty of Medicine, 1750-1 Ikenobe, Miki-cho, Kita-gun, Takamatsu 761-0793, Japan
3. Department of Gastroenterology and Hepatology, Kindai University Faculty of Medicine, 377-2 Ohno-higashi Osaka-sayama, Osaka 589-8511, Japan