[1] Tokyo Metropolitan Toshima Hosp, Dept Neurosurg, Itabashi Ku, Tokyo 1750013, Japan
[2] Tokyo Metropolitan Toshima Hosp, Dept Internal Med, Tokyo 1750013, Japan
[3] Tokyo Med & Dent Univ, Dept Neurosurg, Tokyo, Japan
[4] Tokyo Metropolitan Inst Gerontol, Dept Cell Biol, Tokyo, Japan