1. Stereological Research and Electron Microscopical Laboratory, University of Aarhus, Aarhus C, Denmark
2. Departments of Medicine and Physiology, Diabetes & Metabolism Unit, Boston Medical Center, Boston University School of Medicine, Boston, Massachusetts
3. Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri
4. Department of Pathology, Washington University School of Medicine, St. Louis, Missouri