1. Division of Endocrinology and Diabetology, Medical Faculty, Heinrich-Heine University, Düsseldorf, Germany
2. Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich-Heine University, Düsseldorf, Germany
3. German Center for Diabetes Research, München-Neuherberg, Germany
4. Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX
5. Institute of Pathology, Medical Faculty, Heinrich-Heine University, Düsseldorf, Germany
6. General Surgery Department, Schön Clinic, Düsseldorf, Germany