1. SOS Doctors, Athens, Greece
2. Department of Medicine, Euroclinic General Clinic, Athens, Greece
3. Alfa Institute of Biomedical Sciences (AIBS), Athens, Greece
4. Department of Gastroenterology, Euroclinic General Clinic, Athens, Greece
5. Department of Medicine, Henry Dunant Hospital Center, Athens, Greece
6. Department of Medicine, Tufts University School of Medicine, Boston, MA, USA