[1] Jichi Med Univ, Sch Med, Shimotsuke, Tochigi, Japan
[2] Tohoku Univ, Sch Med, Sendai, Miyagi, Japan
[3] Katta Publ Gen Hosp, Shiroishi, Japan
[4] Keio Univ, Sch Med, Tokyo, Japan
[5] Osaka Univ, Grad Sch Med, Suita, Osaka, Japan
[6] Daiichi Sankyo Co Ltd, Tokyo, Japan