1. Department of Medical Biochemistry, University of Wales College of Medicine, Heath Park, Cardiff, CF14 4XN, UK
2. Department of Pediatrics, Dokkyo University School of Medicine, Mibu, Tochigi 321, Japan
3. Department of Clinical Pathology, Juntendo University School of Medicine, Tokyo 113, Japan
4. Department of Child Health, University of Wales College of Medicine, Heath Park, Cardiff, CF14 4XN, UK