1. Department of Medicine and Division of Gastroenterology and Hepatology, The Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
2. Department of Medicine and Division of Gastroenterology and Hepatology, Indiana University School of Medicine, Indianapolis, Indiana, USA
3. Division of Gastroenterology and Hepatology, University of Colorado, School of Medicine, Aurora, Colorado, USA
4. Department of Gastroenterology and Nutrition, Geisinger Medical Center, Danville, Pennsylvania, USA
5. Division of Gastroenterology, Hepatology and Nutrition, University of Minnesota, Minneapolis, Minnesota, USA
6. Department of Gastroenterology and Hepatology, University Medical Center Utrecht, Utrecht, The Netherlands