[1] Yokohama City Univ, Med Ctr, Ctr Inflammatory Bowel Dis, Yokohama, Kanagawa, Japan
[2] Yokohama City Univ, Med Ctr, Gastroenterol Ctr, Yokohama, Kanagawa, Japan
[3] Keio Univ, Sch Med, Dept Internal Med, Tokyo 108, Japan
[4] Yokohama City Univ, Dept Gastroenterol, Yokohama, Kanagawa, Japan