ACVP > 2007 ACVP Annual Meeting

American College of Veterinary Pathologists >

2007 ACVP Annual Meeting

2007 ACVP Veterinary Student Poster Awards

Experimental Pathology: $250 to individual and $250 to student chapter

Student Poster Abstract #21
p19 Arf Expression in Transient Vasculature Systems.
A. McCalla-Martin, North Carolina State University College of Veterinary Medicine, Raleigh, NC; J. Thornton, M. Mary and S. Skapek, St. Jude Children’s Research Hospital, Memphis, TN

The Arf gene, encoding p19Arf, is an important tumor suppressor that is disrupted in a variety of human cancers. While p19Arf is noted for its ability to induce p53, another tumor suppressor, more recent work shows that p19Arf may also impede tumor development through p53-independent mechanisms. One such mechanism involves p19Arf’s newly-found p53-independent role guiding hyaloid artery regression. Our lab discovered that Arf’s expression in perivascular cells of the hyaloid artery (HA) is imperative for normal mouse eye development. In the absence of p19Arf, proliferating perivascular cells accumulate within the vitreous and the HA fails to regress, thereby leading to a pathological process resembling human persistent hyperplastic primary vitreous. To further explore p19Arf’s role in transient vascular systems we created a mouse in which exon 1 beta of the Arf gene was replaced by the LacZ reporter gene. With LacZ under control of the Arf promoter, we were able to successfully track gene expression via whole mount X-gal staining. We noted Arf promoter activity in previously published locations such as in the HA and seminiferous tubules. In addition, we also found Arf to be expressed in perivascular cells of the umbilical arteries and vein. Strikingly, in our Arf-null mouse, we found accumulation of these perivascular cells along the umbilical vessels – similar to the accumulation seen around the hyaloid artery. These findings give credence to our hypothesis that p19Arf plays an important role in vascular regulation. Future experiments with this mouse model will allow a novel approach to examining p19Arf’s role in vascular regulation and may provide therapeutic insight on Arf’s potential role in destabilizing tumor vasculature.

Clinical Pathology: $250 to individual and $250 to student chapter

Student Poster Abstract #11
BVDV2-INDUCED HYPOMYELINOGENESIS IN A LONGHORN CALF.
D.G. Garneau, B.F. Porter, J.F. Ridpath, H.R. Payne, J.J. Janke, and J.F. Edwards
Department of Veterinary Pathobiology, Texas A&M University, College Station, TX

A newborn Longhorn heifer calf presented to the Veterinary Teaching Hospital at Texas A&M University with generalized tremors, muscle fasciculations, ataxia and nystagmus. In utero infection with bovine viral diarrhea virus (BVDV) was suspected. The animal was euthanized and a necropsy was performed. On gross examination, no significant neurologic lesions were observed. Histopathological evaluation revealed a mild, diffuse, reactive microgliosis/astrocytosis and minimal, lymphocytic, perivascular cuffing. Luxol fast blue and Weil stains showed decreased myelin staining in the brain and spinal cord and electron microscopy was used to confirm thinning of the myelin sheaths. Immunohistochemical stains were strongly positive for BVDV. BVDV was isolated from the brain and phylogenetic analysis of the virus using 5’UTR sequence standards identified the strain as BVDV type 2. BVDV-induced hypomyelinization is rare and analogous to lesions found in neonates affected by border disease and hog cholera. This case is the first documentation of hypomyelinogenesis in a calf specifically attributed to BVDV type 2.

. . . . . . . . .