1. Department of Marine Ecosystem Dynamics, Division of Marine Life Science, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa 277-8564, Japan
2. Department of Regulatory Physiology, Dokkyo Medical University School of Medicine, Tochigi 321-0293, Japan
3. Division of Internal Medicine, Goi Hospital, Ichihara 290-0056, Japan
4. Faculty of Home Economics, Aichi Gakusen University, Okazaki 444-8520, Japan