1. Department of Gastroenterology; University Hospital of Larisa; Larisa Greece
2. Department of Internal Medicine; Second Medical Clinic; Ippokration Hospital; Aristotle University of Thessaloniki; Thessaloniki Macedonia Greece
3. First Laboratory of Pharmacology; School of Medicine; Aristotle University of Thessaloniki; Thessaloniki Macedonia Greece
4. Department of Gastroenterology and Hepatology; University of Zurich; Zurich Switzerland