1 Department of Clinical Sciences at South Bristol, Bristol, UK. m.birchall@ucl.ac.uk.
2 Royal United Hospital Bath MHS Trust, Bath, UK. m.birchall@ucl.ac.uk.
3 Royal National Throat Nose and Ear Hospital, University College London, 330-332, Gray's Inn Road, London, WC1X 8EE, UK. m.birchall@ucl.ac.uk.
4 Blond McIndoe Laboratories, Tissue Injury and Repair Research Group, School of Clinical and Laboratory Sciences, University of Manchester, Manchester, UK.
5 Department of Integrative Medical Biology, Section of Anatomy, Umeå University, SE-901 87, Umeå, Sweden.
6 Division of Companion Animals Science, Department of Clinical Veterinary Sciences, Faculty of Biomedical Sciences, University of Bristol, Bristol, UK.
7 Division of Veterinary Pathology, Infection and Immunity, Department of Clinical Veterinary Sciences, Faculty of Biomedical Sciences, University of Bristol, Bristol, UK.
8 Department of Surgery, North Bristol NHS Trust, Bristol, UK.
9 Department of Cardiothoracic Surgery, Hospital Careggi, Florence, Italy.