(19)

(11)

EP 0 442 914 A1

(12)

(43) Date of publication: 28.08.1991 Bulletin 1991/35 (21) Application number: 89912120.0 (22) Date of filing: 19.10.1989

(51) International Patent Classification (IPC):  A61M 16/ 04( . ) (86) International application number: PCT/GB1989/001239 (87) International publication number: WO 1990/004992 (17.05.1990 Gazette 1990/11)

(84) Designated Contracting States: DE FR GB SE (30) Priority: 08.11.1988 GB 19880026170 04.01.1989 GB 19890000009 (71) Applicant: University of Leeds Industrial Services Ltd. Leeds LS2 3AR, West Yorkshire (GB)	(72) Inventors: INGLIS, Timothy Leeds LS2 3AR (GB) MILLAR, Michael Leeds LS2 3AR (GB) (74) Representative: Orr, William McLean, et al  URQUHART-DYKES & LORD 8th Floor, Tower House Merrion Way Leeds West Yorkshire, LS2 8PA Leeds West Yorkshire, LS2 8PA (GB)