1. Department of Medicine Second Medical Clinic Ippokration Hospital Aristotle University of Thessaloniki Thessaloniki Macedonia Greece
2. Department of Gastroenterology 401 General Military Hospital of Athens Athens Attiki Greece
3. Department of Gastroenterology and Hepatology University of Zurich Zurich Switzerland
4. First Department of Pharmacology Department of Medicine Ippokration Hospital Aristotle University of Thessaloniki Thessaloniki Macedonia Greece