1. Department of Histochemistry, Royal Postgraduate Medical School, Hammersmith Hospital, London W12 OHS, United Kingdom
2. Department of Medicine, School, Hammersmith Hospital, London W12 OHS, United Kingdom
3. Department of Biochemistry II, Karolinska Institute, S-104 01 Stockholm, Sweden
4. Division of Psychiatry, Clinical Research Centre, Harrow, Middlesex HAI 3UJ, United Kingdom