[1] Gen Infirm, Leed Inst Minimally Invas Therapy, Ctr Digest Dis, Leeds LS1 3EX, W Yorkshire, England
[2] Univ Leeds, Div Surg, Acad Surg Unit, Leeds, W Yorkshire, England
[3] Royal Infirm, Scottish Natl Blood Transfus Serv, Edinburgh, Midlothian, Scotland