1. Department of Public Health; Niigata University School of Medicine; Niigata Niigata 951-8510 Japan
2. Division of Pharmacy; Niigata University Medical Hospital; Niigata Niigata 951-8520 Japan
3. Department of Medicine II; Niigata University School of Medicine; Niigata Niigata 951-8510 Japan
4. Niigata Prefecture Research Laboratory for Health and Environmental Protection; Niigata Niigata 950-2144 Japan