[1] Tokyo Metropolitan Komagome Hosp, Dept Internal Med, Bunkyo Ku, Tokyo 1138677, Japan
[2] Kansai Med Univ, Dept Gastroenterol & Hepatol, Osaka, Japan
[3] Shinshu Univ, Ctr Hlth Safety & Environm Management, Matsumoto, Nagano 390, Japan
[4] Tohoku Univ, Grad Sch Med, Div Gastroenterol, Sendai, Miyagi 980, Japan
[5] Kyushu Univ, Grad Sch Med Sci, Dept Surg & Oncol, Fukuoka 812, Japan