1. Laboratory of Anatomy; Department of Biomedical Sciences; Graduate School of Veterinary Medicine; Hokkaido University; Kita-ku Sapporo Japan
2. Section of Biological Safety Research; Chitose Laboratory; Japan Food Research Laboratories; Chitose Hokkaido Japan
3. Department of Histology and Cytology; Faculty of Veterinary Medicine; Zagazig University; Zagazig Egypt