[1] Tokyo Metropolitan Univ, Grad Sch Human Hlth Sci, Lab Regener Neurosci, Tokyo 158, Japan
[2] Chiba Univ, Grad Sch Sci, Chiba, Japan
[3] Yokohama City Univ, Sch Med, Dept Biochem, Yokohama, Kanagawa 232, Japan
[4] Tokyo Metropolitan Inst Gerontol, Tokyo, Japan
[5] Kogakuin Univ, Dept Appl Chem, Tokyo, Japan