Haskins, Mark EAguirre, Gustavo DJezyk, Peter FSchuchman, Edward HDesnick, Robert JPatterson, Donald F2023-05-232023-05-231991-06-012013-08-20https://repository.upenn.edu/handle/20.500.14332/48938Reproduced from Am J Pathol 1991, 138 (6): 1553–1555 with permission from the American Society for Investigative Pathology (http://www.journals.elsevierhealth.com/periodicals/ajpa/home). The archived version of this article can also be found online at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1886403/Comparative and Laboratory Animal MedicineDiseasesMedicine and Health SciencesVeterinary MedicineArticle