1. Northwestern University Feinberg School of Medicine (M.E.M.), Chicago, Illinois 60611
2. University of North Carolina School of Medicine (D.R.C.), Chapel Hill, North Carolina 27599
3. National Institute of Diabetes, Digestive and Kidney Disease (S.M.), National Institutes of Health, Bethesda, Maryland 20892
4. University of Washington, Veterans Affairs Puget Sound Health Care System (G.R.M.), Seattle and Tacoma, Washington 98493
5. Christie Hospital (S.M.S.), Charlottesville, Virginia 22908
6. Manchester M20 4BX, United Kingdom; and University of Virginia Health Science Center (M.L.V.), Charlottesville, Virginia 22908