1. T-Cell Research Institute; Sendai Miyagi 989-3204 Japan
2. Miyagi Prefectural Animal Industry Experiment Station; Miyagi 989-6445 Japan
3. Department of Animal Reproduction; Miyagi Agricultural College Research Farm; Sendai Miyagi 982-0231 Japan
4. Department of Animal Science; Faculty of Agriculture, Tohoku University; Sendai Miyagi 989-0914 Japan
5. Department of Clinical Laboratory Science; Osaka Prefecture College of Health Sciences; Habikino Osaka 583-8555 Japan