1. Department of Medicine (M.K., G.K.), University of Calgary, Calgary, Alberta, Canada T2N 4J8
2. Department of Pathology and Laboratory Medicine (F.G.), University of Calgary, Calgary, Alberta, Canada T2N 2N1
3. Department of Orthopaedic Surgery (M.H.), University of California, Los Angeles, California 90095-7358
4. Department of Clinical Neurosciences (C.W.), University of Calgary, Calgary, Alberta, Canada T2N 2T9