2006 merck/merial - School of Veterinary Medicine - Louisiana State ...

NOT IN ATTENDANCEImmunophenotypic and Clinicopathologic Characterization of Nasal Lymphoma in 36 CatsAimee C. Brooks, Kristen R. Friedrichs, Karen M. Young, Howard S. Steinberg.Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WILymphoma is a common tumor of domestic cats and in the past comprised up to 50% of all feline neoplasia. Unlikemulticentric lymphoma, feline nasal lymphoma tends to invade locally rather than manifest as a systemic disease. We areconducting a retrospective study of all cats with a diagnosis of nasal lymphoma, made by histopathologic examination of tissuecollected by biopsy or at necropsy, at the University of Wisconsin-Madison Veterinary Medical Teaching Hospital from 1992-2005. The purpose of the study is to characterize the immunophenotype of the tumor and the clinicopathologic features of thedisease. Thirty-six cats with nasal lymphoma have been identified. Immunohistochemical characterization of the tumor phenotypeusing commercially available antibodies to CD3, CD79a, MHC II, and CD18 is ongoing. In addition, tissue sections are beingstained with antibodies to FeLV gp70 to assess FeLV infection status. Finally, the medical records are being reviewed forinformation on signalment, history, including exposure to tobacco smoke, presenting signs, presence of concurrent disease,abnormalities in laboratory data, and results of FeLV/FIV serologic tests. Based on preliminary data, the cats in our study had amean age of 10.7 years, and 64% of the cats were male. A better understanding of the characteristics of this disease should lead toimprovements in diagnosis and treatment and contribute to our overall understanding of the biologic behavior of nasal lymphomain cats.Prolactin modulates estrogen induced mammary epithelial cell proliferation in aging female miceTara L. Grafwallner-Huseth*, Lisa M. Arendt, Linda A. SchulerDepartment of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-MadisonBreast cancer is the second leading cause of cancer death in women. Hormones that regulate development andfunction of the mammary gland have been implicated in the pathogenesis of this disease. While the role of prolactin (PRL) inbreast cancer has been controversial, recent human studies have demonstrated a link between PRL and breast cancer.Transgenic mice have been developed that overexpress PRL under control of the promoter, neu-related lipocalin (NRL).NRL-PRL virgin female mice develop ER +/- mammary tumors with long latency, with similarities to post-menopausaldisease. We used this model to examine the interaction of PRL and 17â-estradiol (E2), a risk factor for human disease, in theaging mouse mammary gland. Virgin female NRL-PRL and non-transgenic mice were treated with ovariectomy, shamsurgery, or ovariectomy with long-term E2 treatment beginning shortly after puberty. Disease progression was assessed at 6months and 2 years of age or until tumor development. Surprisingly, manipulation of serum E2 did not change tumor latencyor histotype in NRL-PRL mice. Mammary glands from NRL-PRL females responded similarly compared to non-transgenicfemales but developed focal epithelial hyperplasias and dilated ducts. To examine the effect of aging on proliferation, BrdUmarked epithelial cells were detected by immunohistochemistry and assessed in alveolar and ductal structures. Nontransgenicmice demonstrated increased proliferation with aging in all treatment groups. Aging alone did not enhanceproliferation in NRL-PRL females; however treatment with ovariectomy and E2 enhanced proliferation with age. Weconclude that mammary PRL enhances epithelial proliferation early, which may increase target cells for tumor development,but remains responsive to estrogen manipulation. By examining the mechanisms of PRL and E2 in mammary tumordevelopment, new therapies targeting these hormones may be developed to improve breast cancer treatment.Synovium and Ruptured Ligament Contain CD4+ and CD8+ T Lymphocytes in Dogs with Chronic StifleSynovitis and Degenerative Cranial Cruciate Ligament RuptureKelly JL (jlkelly@wisc.edu); Tewari K; Schaefer SL; Manley PA; Hao Z; Suresh M; Muir P(muirp@svm.vetmed.wisc.edu)Comparative Orthopaedic Research Laboratory, University of Wisconsin-Madison, School of VeterinaryMedicine, Madison, WIIntroduction: Chronic joint inflammation is an important factor promoting progressive degradation of synovialjoints. In the dog, development of chronic inflammatory stifle arthritis and associated degenerative cranial cruciate ligament(CCL) rupture is a commonly naturally occurring condition. The synovium of affected dogs contains a mixture ofinflammatory cells which include activated macrophages, B lymphocytes, T lymphocytes, and CD1c+ MHC class II dendriticcells histologically; in the normal canine stifle, very few synovial inflammatory cells are found.To further understanding of the pathogenesis of joint inflammation in the canine stifle, we determined the phenotypeof T lymphocytes within the synovium of affected dogs and quantified numbers of CD4+ helper and CD8+ cytotoxic Tlymphocytes within joint tissues and peripheral blood. We hypothesized that large populations of synovial T lymphocytes,particularly CD4+ lymphocytes, would be readily detectable within the knee joint of affected dogs.Materials and Methods: Peripheral blood and specimens of synovium and ruptured ACL were collected from dogswith inflammatory stifle arthritis/degenerative ACL rupture during surgical treatment. Peripheral blood mononuclear cells155