1. Blood Pressure Unit, Department of Medicine, St. George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, U.K.
2. Clinical Pharmacology Unit, Department of Pharmacology & Clinical Pharmacology, St. George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, U.K.
3. Dermatology Unit, Department of Medicine, St. George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, U.K.