1. Division of Endocrinology, Diabetology, Angiology, Nephrology; Pathobiochemistry and Clinical Chemistry; Department of Internal Medicine; University of Tuebingen; Tuebingen Germany
2. Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Zentrum Muenchen; University of Tuebingen; Tuebingen Germany
3. German Center for Diabetes Research (DZD); Neuherberg Germany
4. Institute of Clinical Biochemistry and Pathobiochemistry; German Diabetes Center; Dusseldorf Germany