1. From the Department of Pathology and Laboratory Medicine (Drs Nelson, Geller, and Petrovic) and Division of Gastroenterology, Department of Medicine (Drs Fernandes and Woolf), Cedars-Sinai Medical Center, Los Angeles, Calif.
2. Reprints: Lydia M Petrovic, MD, Department of Pathology, Mayo Clinic, 200 First St SW, Rochester, MN 55905.