[1] Klin Hirslanden, Ctr Gastroenterol, CH-8008 Zurich, Switzerland
[2] Changi Gen Hosp, Div Gastroenterol, Singapore, Singapore
[3] Kitasato Univ, East Hosp, Dept Gastroenterol, Kanagawa, Japan
[4] Univ Med Ctr Hamburg Eppendorf, Dept Interdisciplinary Endoscopy, Hamburg, Germany