[1] Gifu Univ Hosp, Dept Internal Med 1, Gifu 5011194, Japan
[2] Hokkaido Univ, Dept Gastroenterol & Hepatol, Grad Sch Med, Sapporo, Hokkaido, Japan
[3] Sapporo Med Univ, Sch Med, Dept Internal Med 4, Sapporo, Hokkaido, Japan
[4] Japan Red Cross Date Gen Hosp, Dept Gastroenterol, Date, Japan
[5] Fukushima Med Univ Hosp, Dept Gastroenterol, Fukushima, Japan
[6] Gifu Municipal Hosp, Dept Gastroenterol, Gifu, Japan
[7] Teine Keijinkai Hosp, Ctr Gastroenterol, Sapporo, Hokkaido, Japan
[8] Yokohama City Univ, Div Gastroenterol, Grad Sch Med, Yokohama, Kanagawa 232, Japan
[9] Gifu Prefectural Gen Med Ctr, Dept Gastroenterol, Gifu, Japan
[10] Showa Univ, Northern Yokohama Hosp, Ctr Digest Dis, Yokohama, Kanagawa, Japan
[11] Aichi Canc Ctr Hosp, Dept Gastroenterol, Nagoya, Aichi 464, Japan
[12] Tokyo Med Univ, Dept Gastroenterol & Hepatol, Tokyo 1608402, Japan
[13] Onomichi Gen Hosp, Ctr Gastroendoscopy, Onomichi, Japan