1. Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.
2. Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.
3. Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.
4. Advanced Cell Technology, Worcester, Massachusetts.
5. Current affiliation: Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada.