1. Department of Medicine I; University of Erlangen-Nuremberg; Erlangen Germany
2. Ludwig Demling Endoscopy Center of Excellence; University Hospital Erlangen; Erlangen Germany
3. Digestive Disease Center; Showa University Northern Yokohama Hospital; Yokohama; Japan
4. Klinik Innere Medizin II; HSK, Dr. Horst Schmidt Kliniken; Wiesbaden Germany