1. Department of Gastroenterology, General Hospital of Nea Ionia “Konstantopoulio-Patision”, 3-5, Theodorou Konstantopoulou, 14233 Athens, Greece
2. 1st Department of Internal Medicine, 251 Hellenic Air Force & VA General Hospital, 11525 Athina, Greece
3. Department of Gastroenterology, General University Hospital of Larissa, 41334 Larissa, Greece
4. Endoscopy Unit, Cleveland Clinic London, London SW1X 7HY, UK
5. Hepatogastroenterology Unit, Second Department of Internal Medicine, Propaedeutic, Medical School, National and Kapodistrian University of Athens, ‘‘Attikon” University General Hospital, 77591 Athens, Greece