1. Medical Research Institute, Kyoto Industrial Health Association, 67 Kitatsuboi-cho, Nishinokyo, Nakagyo-ku, Kyoto 604-8472, Japan
2. Research Organization of Science and Technology, Ritsumeikan University, Kusatsu 525-8577, Japan
3. Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan