1. Department of Veterinary Preclinical Sciences, University of Glasgow Veterinary School (P.J.O., P.B.), Glasgow, Scotland G61 1QH
2. the Department of Human Anatomy, University of Oxford (U.S., H.M.C.), Oxford, United Kingdom OX1 3QX
3. the Department of Physiology, University of Turku (A.-M.H., I.H.), 20520 Turku, Finland