1. School of Biomedical Sciences, Kent State University, Integrated Sciences Building, P.O. Box 5190, Kent, Ohio 44242, U.S.A.,
2. Musculoskeletal Research Group, Department of Anatomy and Neurobiology, Northeast Ohio Medical University, 4209 State Route 44, Rootstown, Ohio 44272, U.S.A.
3. Department of Biology, West Chester University, 730 South Church Street, West Chester, Pennsylvania 19383, U.S.A.
4. Department of Anatomy, College of Medicine, 520 W. St., NW, Howard University, Washington, D.C. 20059, U.S.A.