1Eastern Virginia School of Medicine, Norfolk, Virginia, USA
2Georgetown University Medical School, Washington, DC, USA
3University of Wisconsin Medical School, Milwaukee, Wisconsin, USA
4University of Illinois at Chicago Medical Center, Chicago, Illinois, USA
5Private Practice, Hollywood, Florida, USA
6AstraZeneca LP, Wayne, Pennsylvania, USA
Reprint requests and correspondence: David A Johnson, MD, Digestive & Liver Disease Specialists, Suite 114, 885 Kempsville Road, Norfolk, VA 23502.
Received 16 October 2000; accepted 23 October 2000