1. Department of Anatomy and Cell Biology, University Hospital, RWTH Aachen University, Aachen, Germany
2. Institute of Neuroanatomy, University Hospital, RWTH Aachen University, Aachen, Germany
3. Department of Orthopaedic Surgery, University Hospital, RWTH Aachen. Germany
4. Department of Laboratory Medicine, University of California San Francisco, San Francisco, CA 94115, U.S.A.
5. Department of Internal Medicine III - Gastroenterology and Metabolic Disorders, University Hospital RWTH Aachen, Aachen, Germany