1. Cambridge Antibody Technology Ltd., The Science Park, Melbourn SG8 6JJ, U.K.
2. Eukarion, Inc., 6F Alfred Circle, Bedford, MA 01739, U.S.A.
3. Department of Neuroscience, GlaxoWellcome Medicines Research Centre, Gunnel's Wood Road, Stevenage SG1 2NY, U.K.