[1] Univ Tsukuba, Inst Clin Med, Dept Neurol, Tsukuba, Ibaraki 3050006, Japan
[2] Univ Tsukuba, Inst Clin Med, Dept Nephrol, Tsukuba, Ibaraki 3050006, Japan
[3] Osaka City Univ, Sch Med, Dept Neurosci, Osaka, Japan
[4] Niigata Univ, Brain Res Inst, Dept Neurol, Niigata 951, Japan
[5] Niigata Univ, Brain Res Inst, Dept Pathol, Niigata 951, Japan
[6] Teikyo Univ, Sch Med, Ichihara Hosp, Dept Neurol, Chiba, Japan