1. NHS Greater Glasgow and Clyde Clinical Biochemistry Service and College of Medical, Veterinary and Life Sciences, University of Glasgow, Department of Biochemistry, Gartnavel General Hospital, 1053 Great Western Road, Glasgow G12 0YN
2. Vascular Biochemistry Section, Institute of Cardiovascular & Medical Sciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, 2nd floor McGregor Building, Western Infirmary, Glasgow G11 6NT, UK