[1] Hokkaido Univ, Sch Med, Sapporo, Hokkaido 060, Japan
[2] Saitama Int Med Ctr, Saitama, Japan
[3] Tohoku Univ Hosp, Sendai, Miyagi, Japan
[4] Miyagi Canc Ctr, Sendai, Miyagi, Japan
[5] Sendai Kousei Hosp, Sendai, Miyagi, Japan
[6] Niigata Univ, Med & Dent Hosp, Niigata, Japan
[7] Kokka Komuin Kyosai Kumiai Rengokai Sapporo Med C, Sapporo, Hokkaido, Japan
[8] Natl Hosp Org, Hokkaido Canc Ctr, Sapporo, Hokkaido, Japan
[9] Hokkaido Univ, Grad Sch Med, Sapporo, Hokkaido, Japan
[10] Kesennuma City Hosp, Kesennuma, Miyagi, Japan
[11] Kanagawa Cardiovasc & Resp Ctr, Yokohama, Kanagawa, Japan
[12] Hokkaido Social Insurance Hosp, Sapporo, Hokkaido, Japan
[13] Nippon Med Sch, Sendagi, Japan
[14] Hirosaki Univ, Grad Sch Med, Hirosaki, Aomori, Japan
[15] Yokohama City Univ, Med Ctr, Yokohama, Kanagawa 232, Japan
[16] Saitama Med Univ, Saitama, Japan
[17] Tohoku Univ, Grad Sch Med, Sendai, Miyagi 980, Japan