1. Institute of Medical Science (D.C.T.), University of Toronto, Canada.
2. Division of Cardiac Surgery (D.C.T., S.V.), St Michael’s Hospital, Toronto, Canada.
3. Department of Surgery (S.V.), University of Toronto, Canada.
4. Department of Pharmacology (D.A.H.), University of Toronto, Canada.
5. Division of Vascular Surgery (D.A.H.), St Michael’s Hospital, Toronto, Canada.
6. Department of Physiology and Pharmacology, Western University, London, Canada (D.A.H.).