1. Department of Physiology, Medical School of National and Kapodistrian University of Athens, Athens, Greece
2. First Department of Internal Medicine, Medical School of National and Kapodistrian University of Athens, Athens, Greece
3. First Propedeutic Department of Internal Medicine, Medical School, Aristotle University of Thessaloniki, AHEPA Hospital, Thessaloniki, Greece
4. Department of Gastroenterology, Medical School of National and Kapodistrian University of Athens, General Hospital of Athens “Laiko”, Athens, Greece