1. Neurosurgical Clinic, University of Tübingen, Tübingen, Germany
2. Medical Clinic IV, University of Tübingen, Tübingen, Germany
3. Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
4. German Center for Diabetes Research (DZD), Neuherberg, Germany