Affiliation: | 1. Division of Gastroenterology, Department of Medicine, David Geffen School of Medicine at UCLA and Sepulveda Ambulatory Care Center, Veterans Affairs Greater Los Angeles Healthcare System, 111G, 16111 Plummer Street, North Hills, CA 91343, USA;2. Department of Internal Medicine, University of Iowa Carver College of Medicine, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, 4612 JCP, Iowa City, IA 52242-1009, USA |