Department of Pathology and Laboratory Medicine, Queen Elizabeth II Health Sciences Centre and Dalhousie University, Halifax, Nova Scotia, Canada
Received February 11, 1998; accepted April 16, 1998.
Address correspondence and reprint requests to Albert D. Fraser, Department of Pathology and Laboratory Medicine, Queen Elizabeth II Health Sciences Centre, 1278 Tower Road, Halifax, Nova Scotia, Canada B3H 2Y9.