[1] Chiba Univ, Grad Sch Med, Dept Neurol, Chuo Ku, Chiba 2608670, Japan
[2] Toho Univ, Sakura Med Ctr, Dept Internal Med, Div Neurol, Sakura, Japan
[3] Chiba Univ Hosp, Cent Lab Unit, Chiba, Japan
[4] Chiba Univ, Grad Sch Med, Dept Urol, Chiba 2608670, Japan
[5] Chiba Univ, Grad Sch Med, Dept Neurosurg, Chiba 2608670, Japan
[6] Chiba Univ Hosp, Clin Res Ctr, Chiba, Japan