[1] Ruhr Univ Bochum, Acad Teaching Hosp, Augusta Krankenanstalt, Dept Gen & Visceral Surg, D-44791 Bochum, Germany
[2] Ruhr Univ Bochum, Dept Dermatol & Allergol, D-44791 Bochum, Germany
[3] Univ Calif Los Angeles, Dept Physiol Sci, Los Angeles, CA 90095 USA