1. Department of Pediatrics, Division of Gastroenterology, Children's Hospital and Regional Medical Center, 4800 Sandpoint Way NE, P.O. Box 5371, Seattle, WA 98105-0371, USA
2. Department of Pathology, Children's Hospital and Regional Medical Center, 4800 Sandpoint Way NE, P.O. Box 5371, Seattle, WA 98105-0371, USA