1. Medical Histology and Cell Biology Department, Faculty of Medicine, Zagazig University, Zagazig, Egypt
2. Anatomy and Histology Department, College of Medicine, Qassim University, Elmulida, KSA
3. Department of Medical Biochemistry, Faculty of Medicine, Zagazig University, Zagazig, Egypt
4. Department of Science, Faculty of Preparatory Year of Health Sciences, PNU University, Riyadh, KSA