[1] Rhein Westfal TH Aachen, Univ Hosp, Dept Anat & Cell Biol, Aachen, Germany
[2] Rhein Westfal TH Aachen, Univ Hosp, Inst Neuroanat, Aachen, Germany
[3] Rhein Westfal TH Aachen, Univ Hosp, Dept Orthopaed Surg, Aachen, Germany
[4] Univ Calif San Francisco, Dept Lab Med, San Francisco, CA 94115 USA
[5] Univ Hosp RWTH Aachen, Dept Internal Med Gastroenterol & Metab Disorders, Aachen, Germany