1. Division of Metabolism, Endocrinology and Nutrition, University of Washington, Seattle, WA 98110, USA.
2. Harborview Medical Center, 325 Ninth Avenue, Seattle, WA 98110, USA.
3. Division of Metabolism, Diabetes and Endocrinology, University of California San Diego, San Diego, CA 92161, USA.
4. Division of Metabolism, Diabetes and Endocrinology, VA San Diego Health Care System, 3350 La Jolla Village Drive, San Diego, CA 92161, USA.