1. Cellular and Molecular Biotechnology Research Institute, National Institute of Advanced Industrial Science and Technology, Central-5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
2. Konica Minolta, Inc., No. 1 Sakura-machi, Hino, Tokyo 191-8511, Japan
3. Department of Obstetrics and Gynecology, St. Marianna University of Medicine, 2-16-1 Sugao, Miyamae-ku, Kawasaki, Kanagawa 216-8511, Japan
4. Department of Obstetrics and Gynecology, Tokai University, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan