[1] Teine Keijinkai Hosp, Dept Hematol, Teine Ku, Sapporo, Hokkaido 0068555, Japan
[2] Teine Keijinkai Hosp, Dept Pediat, Teine Ku, Sapporo, Hokkaido 0068555, Japan
[3] Teine Keijinkai Hosp, Dept Cardiovasc Surg, Teine Ku, Sapporo, Hokkaido 0068555, Japan
[4] Teine Keijinkai Hosp, Dept Internal Med, Teine Ku, Sapporo, Hokkaido 0068555, Japan