1. Department of Bacteriology; The Jikei University School of Medicine; Minato-ku Tokyo 105
2. Department of Orthopaedics; The Jikei University School of Medicine; Minato-ku Tokyo 105
3. Department of Periodontology; Nippon Dental University; Chiyoda-ku Tokyo 102
4. Department of Clinical Pathology; Jisan Junior College; Dongrae-ku Pusan 607 Korea