1. From the Departments of Medicine (Drs. H. Ali, J. Sieck, Dossing, Saour); Biological and Medical Research (Dr. El-Yazigi, Mr. Raines); Pathology and Laboratory Medicine (Dr. M. Ali); Oncology (Dr. Ernst); and Biomedical Statistics and Scientific Computing (Dr. Khan); King Faisal Specialist Hospital and Research Centre, Riyadh