1. Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 3BG, UK
2. Jacqui Wood Cancer Centre, Division of Cancer Research, Medical Research Institute, University of Dundee, Dundee DD1 9SY, UK
3. Neurometabolic Unit, National Hospital, Queen Square, London WC1N 3BG, UK
4. Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai 980-8575, Japan
5. Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA