1. Division of Gastroenterology; University of Pennsylvania; Philadelphia PA
2. Department of Epidemiology and Biostatistics; University of Pennsylvania; Philadelphia PA
3. VA Connecticut-Healthcare System; West Haven CT
4. Corporal Michael J. Crescenz VA Medical Center; Philadelphia PA
5. Minneapolis VA Health Care System; Minneapolis MN
6. VA New York Harbor Health Care System; Brooklyn NY
7. Boston VA Healthcare System; Boston MA
8. San Francisco VA Medical Center; San Francisco CA
9. James J. Peters VA Medical Center; Bronx NY
10. University of Bern; Bern Switzerland
11. Bayer HealthCare Pharmaceuticals; Whippany NJ