1. Department of Neurology, University of Ulm, Helmholtzstr. 8/1, 89081 Ulm, Germany
2. Department of Applied Physiology, University of Ulm, Helmholtzstr. 8/1, 89081 Ulm, Germany
3. Division for Biochemistry of Joint and Connective Tissue Diseases, Department of Orthopaedics, University of Ulm, Helmholtzstr. 8/1, 89081 Ulm, Germany
4. Division of Endocrinology, Department of Internal Medicine, University of Ulm, Helmholtzstr. 8/1, 89081 Ulm, Germany
5. Department of Neurology, University of Leipzig, Liebigstr. 22a, 04103 Leipzig, Germany
6. Division of Biology, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA