[1] Stanford Univ, Sch Med, Div Gastroenterol & Hepatol, Dept Med, 300 Pasteur Dr,Always Bldg Room M211, Stanford, CA 94305 USA
[2] Boston Healthcare Associates Int GmbH, Berlin, Germany
[3] Charite Med Univ Berlin, Virchow Clin Campus, Berlin, Germany
[4] Steinbeis Univ, Berlin, Germany