[1] Osaka City Univ, Dept Metab Endoclinol, Grad Sch Med, Osaka 558, Japan
[2] Osaka City Univ, Dept Physiol, Grad Sch Med, Osaka 558, Japan
[3] Osaka City Univ, Dept Nucl Med, Grad Sch Med, Osaka 558, Japan
[4] Osaka City Univ, Dept Med Sci Fatigue, Grad Sch Med, Osaka 558, Japan
[5] Kansai Univ Welf Sci, Dept Hlth Sci, Osaka, Japan
[6] RIKEN, CMIS, Kobe, Hyogo, Japan