1. Gastroenterology Department, “Evangelismos” General Hospital, 16121 Athens, Greece
2. Department of Gastroenterology and Hepatology, University Hospital of Ioannina, University of Ioannina, 45110 Ioannina, Greece
3. Gastroenterology Department, NIMTS, 19010 Kalivia, Greece
4. Gastroenterology Department, Red Cross Hospital, 11526 Athens, Greece
5. Gastroenterology Department, 401 Military Hospital of Athens, 11525 Athens, Greece