1. Third Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Hongo, Tokyo, Japan 113.
2. Diabetes Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.
3. Institute for Diabetes Care and Research, Asahi Life Foundation, Marunouchi, Tokyo, Japan 100.
4. Department of Pediatrics, Hokkaido University School of Medicine, Sapporo, Japan 060.