1. Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Shitsukawa 454, Toon, Ehime 791-0295, Japan.
2. Gastroenterology Center, Ehime Prefectural Central Hospital, Ehime, Japan.
3. Center for Liver-Biliary-Pancreatic Diseases, Matsuyama Red Cross Hospital, Ehime, Japan.
4. Department of Gastroenterology, Uwajima City Hospital, Ehime, Japan.