[1] Tokyo Met Inst Gerontol, Res Team Geriatr Med, Tokyo, Japan
[2] Tokai Univ, Sch Med, Dept Pathol, Hiratsuka, Kanagawa, Japan
[3] Nippon Vet & Life Sci Univ, Dept Vet Pathol, Musashino, Tokyo, Japan
[4] Tokyo Met Inst Gerontol, Res Team Geriatr Pathol, Tokyo, Japan