1. 2nd Department of Medicine, Faculty of Medicine at Hradec Kralove, Charles University in Praha, University Teaching Hospital, Sokolska 581, 500 05 Hradec Kralove, Czech Republic
2. Clinique des Maladies Intestinales et du Support Nutritionnel, Service de Gastroentérologie, Hôpital Erasme, Route de Lennik 808, 1070 Brussels, Belgium
3. Department of Gastroenterology, VU University Medical Center, Amsterdam, The Netherlands
4. Department of Gastroenterology, Slovak Medical University in Bratislava, University Teaching Hospital of St. Cyril and Methodius, Antolska 11, 851 07 Bratislava, Slovakia