1. First Department of Internal Medicine, Nagoya University School of Medicine, Nagoya 466–8550;
2. Nagoya Higashi Municipal Hospital, Nagoya 464–0071;
3. Anjo Kosei Hospital, Anjo 446–8602; and
4. First Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807–0804, Japan