1 2nd Department of Internal Medicine-Gastroenterology, Charles University in Praha, Faculty of Medicine at Hradec Kralove, University Teaching Hospital, Sokolska 581, 500 05 Hradec Kralove, Czech Republic.
2 Division of General Internal Medicine, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905, USA.
3 5th Department of Internal Medicine, Comenius University in Bratislava, Faculty of Medicine in Bratislava, University Teaching Hospital, Ruzinovska 6, 826 06 Bratislava, Slovakia.
4 Department of Internal Medicine, First Faculty of Medicine of Charles University and Military University Hospital, U Vojenské nemocnice 1200, 169 02 Prague, Czech Republic.