1. Cardiovascular Research Laboratory, Department of Pathology and Laboratory Medicine, University of British Columbia-St. Paul's Hospital, Vancouver, British Columbia V6Z 1Y6;
2. Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3;
3. Cardiovascular Research Institute, Morehouse Medical School, Atlanta, Georgia, 30310; and
4. Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio 44106-4970