bluuebunny/crossref_metadata_2025 huggingface dataset:
Necrotic Oophoritis in Gilts Associated with Experimental Inoculation of a Viral Gene-deletion Mutant Pseudorabies Vaccine
Authors: Parker R. F. , Foley G. L. , Dangler C. A. , Kaboord W. , Samberg R.
Published: January 2010

Previous work on the reproductive effects of various herpesviruses has demonstrated adverse effects on reproductive function in several host species. Although herpesviral vaccines are used in several species to ameliorate the clinical effects of infection, pathogenicity for reproductive tissue, associated with diminished reproductive efficiency, has been reported to be retained in a live-attenuated vaccine strain of the herpesvirus, bovine herpesvirus-1. The objective of this study was to determine if a gene-deletion mutant, thymidine kinase negative, pseudorabies virus retained acute pathogenicity for the reproductive tract of swine following intravenous inoculation during estrus. Estrous cycles of nulliparous gilts were synchronized by administration of a gonadotropin and daily exposure to a boar. During estrus, six gilts were inoculated intravenously with twice the recommended intramuscular dose of a commercially available viral gene-deletion mutant pseudorabies vaccine. Six control gilts in estrus were sham inoculated intravenously with vaccine diluent during estrus. All animals were euthanatized 10 days postinoculation, and the ovaries and uterus were collected for histopathology following gross examination. All reproductive tracts were grossly normal. Histologically, four of six treated gilts had a mild to moderate, multifocal, necrotizing oophoritis, with the lesions limited to corpora lutea and the adjacent stroma. Ovaries of control gilts exhibited no necrotizing lesions. Both control and pseudorabies vaccine-inoculated gilts had occasional minimal focal mononuclear infiltrates in the ovaries. These data show that live attenuated viral gene-deletion mutant pseudorabies vaccine administered to swine during estrus can result in acute pathogenicity in ovarian corpora lutea. No endocrinologic data is available in these pigs, so the impact on pregnancy maintenance is unknown.
Differential Levels of mRNAs for Cytokines, the Interleukin-2 Receptor and Class II DR/DQ Genes in Ovine Interstitial Pneumonia Induced by Maedi Visna Virus Infection
Authors: Woodall C. J. , Maclaren L. J. , Watt N. J.
Published: January 2010

The relative levels of selected cytokine, interleukin-2 receptor, class II DR and DQ RNAs, and maedi visna virus (MVV) RNA were measured by reverse-transcriptase polymerase chain reaction (RT-PCR) in the lungs of sheep with natural maedi visna virus infection ( n = 8) and a group of age/sex/breed-matched MVV seronegative sheep ( n = 4). These animals were divided into two groups, irrespective of serostatus, according to the severity of lymphocytic interstitial pneumonia. The severity of lung lesions was determined by clinical sign, lung weight, and lesion score in the lungs measured by three pathologic parameters. Sheep with lung lesions showed hyperelevated levels of granulocyte-macrophage colony-stimulating factor upregulated γ-interferon, interleukin 2 receptor, and interleukins 1β, 4, and 10 mRNAs. Class II mRNAs were found not to be elevated in the lungs of sheep with lung lesions. Tumor necrosis factor α and transforming growth factor β1 mRNA levels were similar in all sheep lungs studied. We discuss the major roles played by granulocyte-macrophage colony-stimulating factor and type 2 cytokines in the pathogenesis of this disease and the possible stimulation of the production of these cytokines by viral surface glycoproteins.
Characterization of the Proliferation State in Canine Mammary Tumors by the Standardized AgNOR Method with Postfixation and Immunohistologic Detection of Ki-67 and PCNA
Authors: Löhr C. V. , Teifke J. P. , Failing K. , Weiss E.
Published: January 2010

Paraffin-embedded tissue sections of 96 surgically removed mammary tumors from female dogs were analyzed for their proliferation state using three different methods. The AgNOR method, originally developed by Ploton and coworkers in 1986,34 modified and standardized by the AgNOR committee, is an easy, inexpensive silver-staining procedure used to determine cell proliferation and prognosis of various tumors. Due to the standardized staining protocol of the AgNOR method and a postfixation step, results obtained were of excellent quality for image analysis processing. The growth fraction was evaluated by counting of immuno-histologically positive-stained cells for Ki-67 or proliferating-cell nuclear antigen (PCNA). The values determined were, in general, lower with Ki-67 (MIB1) than with PCNA (PC10). Nevertheless, the labeling indices of these antigens correlated significantly ( P < 0.001). Though the differences of the means between the tumor groups according to the classification system of the World Health Organization were significant for all three investigated methods ( P < 0.001), there was a considerable overlap between the tumor groups concerning all investigated parameters. An exploratory data analysis (multivariate analysis) was performed to evaluate the prognostic relevance of the three methods including further anamnestic, clinical, gross, and histopathologic variables. Besides the histopathologic diagnosis (survival P < 0.001; survival time P < 0.05; reappearance of tumor growth P < 0.05), only the PCNA-labeling index (time until reappearance of tumor growth P < 0.001) was of prognostic significance.
The Immunophenotypic Characterization of Bovine Lymphomas
Authors: Vernau W. , Jacobs R. M. , Valli V. E. O. , Heeney J. L.
Published: January 2010

A prospective analysis of 38 cases of bovine lymphoma was performed. Thirty-five of the lymphomas were considered enzootic because of serologic or molecular biologic association with the bovine leukemia virus (BLV). The three remaining cases were in cattle <1 year of age and were not associated with BLV and hence were considered sporadic lymphomas. Utilizing the National Cancer Institute Working Formulation for the morphologic classification of human non-Hodgkin's lymphoma, 54.3% (19/35) of the enzootic lymphomas were classified as the diffuse large cleaved cell type. The cells of the 35 enzootic lymphomas expressed a consistent immunophenotype represented by MHCII+, γ-heavy chain+, and λ-light chain+; this constellation of markers indicated a mature B-cell phenotype. The three sporadic lymphomas failed to express MHCII antigen despite the presence of other B-cell antigens. There was no correlation between morphologic cell type and immunophenotype in these bovine lymphomas.
Helicobacter mustelae-associated Gastric Adenocarcinoma in Ferrets (Mustela putorius furo)
Authors: Fox J. G. , Dangler C. A. , Sager W. , Borkowski R. , Gliatto J. M.
Published: January 2010

Helicobacter pylori in humans is associated with active, chronic gastritis, peptic ulcer disease, and most recently has been linked epidemiologically to gastric adenocarcinoma. A related organism, Helicobacter mustelae, naturally infects ferrets and also causes a persistent gastritis, a precancerous lesion, and focal glandular atrophy of the proximal antrum. In this report, we document the clinical presentation and histopathologic confirmation of H. mustelae-associated gastric adenocarcinoma in two middle-aged male ferrets. The ferret appears to be well suited to study the pathogenesis of naturally occurring Helicobacter sp.-induced gastric adenocarcinoma.
Testicular Efferent Ductule Cyst of a Dog
Authors: Wakui S. , Furusato M. , Yokoo K. , Ushigome S.
Published: January 2010

A 9-year-old male Shetland Sheepdog had a small mass in the left testis. Grossly, the round to oval cyst was present at the upper pole of the testicular parenchyma near the head of the epididymis. Histologically, the cyst was lined by a single layer of nonciliated and ciliated epithelial cells. Immunohistochemically, the epithelial cells of the cyst showed expression of the low- and high-molecular-weight cytokeratins, vimentin, and desmin similar to that of normal efferent ductules in the dog. The testicular cystic dysplasia was thought to originate from the efferent ductules.
Apocrine Gland Tumor of the Eyelid in a Dog
Authors: Hirai T. , Mubarak M. , Kimura T. , Ochiai K. , Itakura C.
Published: January 2010

A 13-year-old male Shetland Sheepdog with progressive exophthalmos had a neoplastic mass in the ocular adnexa. Histologically, this neoplasm was composed of duct-forming epithelial cells with decapitation secretion. Tumor cells invaded the globe through the tunica conjunctiva and replaced the vitreous body. The cornea, iris, ciliary body, and retina were extensively destroyed. Both the epithelial and spindle-shaped myoepithelial cells showed nuclear atypia and mitotic activity in the globe. The primary tumor was diagnosed as adenocarcinoma, probably originating from apocrine sweat glands of the eyelid, and the infiltrating intraocular neoplasm was diagnosed as a malignant mixed tumor.
Intraerythrocytic Inclusions Associated with Iridoviral Infection in a Fer de Lance (Bothrops moojeni) Snake
Authors: Johnsrude J. D. , Raskin R. E. , Hoge A. Y. A. , Erdos G. W.
Published: January 2010

Intraerythrocytic inclusions associated with infection by an iridovirus were observed in a fer de lance ( Bothrops moojeni) snake that was being evaluated for the presence of renal carcinoma. The erythrocytes contained two types of inclusions, one viral and one crystalline, usually concomitantly. The snake was markedly anemic and exhibited a marked regenerative response. Ultrastructural analysis identified the virus to be an iridovirus consistent with snake erythrocyte virus and the crystalline structures to be of a different nature than hemoglobin.
Primary Amebic Meningoencephalitis Due to Naegleria fowleri in a South American Tapir
Authors: Lozano-Alarcón F. , Bradley G. A. , Houser B. S. , Visvesvara G. S.
Published: January 2010

Naegleria fowleri, Acanthamoeba spp., and Balamuthia mandrillaris are known to cause fatal central nervous system (CNS) disease in human beings. N. fowleri causes acute, fulminating primary amebic meningoencephalitis (PAM), which generally leads to death within 10 days. Acanthamoeba spp. and B. mandrillaris cause chronic granulomatous amebic encephalitis, which may last for 8 weeks. Acanthamoeba spp. and B. mandrillaris also cause CNS disease in animals. N. fowleri, however, has been described only in human beings. This report is the first of PAM in an animal, a South American tapir. Dry cough, lethargy, and coma developed in the animal, and its condition progressed to death. At necropsy, lesions were seen in the cerebrum, cerebellum, and lungs. The CNS had severe, suppurative meningoencephalitis with many neutrophils, fibrin, plasma cells, and amebas. Amebas were 6.5 μm to 9 μm in diameter and had a nucleus containing a large nucleolus. Amebas in the sections reacted with a monoclonal antibody specific for N. fowleri in the immunofluorescent assay and appeared bright green.
Malignant Cauda Equina Paraganglioma in a Cat
Authors: Davis W. P. , Watson G. L. , Koehler L. K. , Brown C. A.
Published: January 2010

An 11-year-old spayed female domestic long-haired cat presented for surgical removal of a slowly growing and deeply invasive 2.5 X 3.5-cm mass cranial to the base of the tail. Light microscopic examination of surgical biopsy specimens revealed an encapsulated mass composed of packets of polygonal cells of various sizes separated by a delicate fibrovascular stroma. Gömöri's reticulum stain revealed a characteristic endocrine or "Zellballen" pattern. Tumor cells contained diffuse positive reactivity to synaptophysin and neuron-specific enolase, reactions consistent with a neuroendocrine neoplasm. S-100 protein-positive cells reminiscent of sustentacular (support) cells occurred singly or in small clusters within tumor packets. At postmortem examination 3 months later, a 9- X 5- X 4-cm multinodular raised tan mass involving the caudal pelvis, sacrum, and tail-head regions was found. The base of this neoplastic mass originated within the cauda equina region and involved approximately five caudal nerve roots. Numerous 1-3-mm metastatic nodules were identified disseminated throughout the pulmonary parenchyma. The tumor was diagnosed as a malignant paraganglioma of the cauda equina region with pulmonary metastasis.
Intravascular Malignant T-cell Lymphoma (Malignant Angioendotheliomatosis) in a Cat
Authors: Lapointe J.-M. , Higgins R. J. , Kortz G. D. , Bailey C. S. , Moore P. F.
Published: January 2010

A 7-year-old spayed female Siamese cat was presented with a 7-day history of ataxia, circling to the right, and involuntary micturition and defecation. Cerebrospinal fluid analysis showed increased protein content and relative eosinophilia. At necropsy, there was flattening of the cerebral cortical gyri of the right frontal and parietal lobes, and both kidneys had multiple wedge-shaped cortical indentations. Histologically, the cerebral cortex contained several extensive malacic foci, and the kidneys had multifocal parenchymal degeneration and atrophy. There was multifocal partial to complete thrombosis of renal interlobar arteries and of the right middle cerebral artery and meningeal branches; these thrombi contained large anaplastic round cells, which often invaded the arterial wall. Many smaller vessels within the kidneys and brain were occluded with clusters of similar cells, without thrombosis or vascular wall invasion. The neoplastic round cells had immunohistochemical staining properties of T lymphocytes.
Neuronal Vacuolation in Raccoons (Procyon lotor)
Authors: Hamir A. N. , Heidel J. R. , Picton R. , Rupprecht C. E.
Published: January 2010

Microscopic vacuolar changes in neuronal perikaryon are described in two free-ranging raccoons ( Procyon lotor) from different geographic locations in the United States. Both animals were negative for rabies and scrapie-associated antigens. Microscopically, lesions were not seen in the neuropil. Neuronal vacuolations have previously been documented in brains of normal animals and in diseases such as rabies and prion-associated encephalopathies. Although experimental transmission of a spongiform mink encephalopathy has been documented in raccoons, a naturally occurring spongiform encephalopathy has not been described in this species. The presence of neuronal vacuolations in the raccoons is novel and requires further investigation to elucidate the mechanism of this phenomenon.
Immunohistochemical Detection of VHS Virus in Paraffin-embedded Specimens of Rainbow Trout (Oncorhynchus mykiss): The Influence of Primary Antibody, Fixative, and Antigen Unmasking on Method Sensitivity
Authors: Evensen Ø. , Olesen N. J.
Published: January 2010

The influence of the primary antibody, the fixative, and the antigen unmasking technique on the method sensitivity of immunohistochemistry as a method for the identification of viral hemorrhagic septicemia (VHS) virus in paraffin-embedded specimens of naturally infected rainbow trout ( Oncorhynchus mykiss) was examined. Fish (200-300 g) were collected during an outbreak of VHS. Parallel specimens from liver, spleen, kidney, and brain were fixed by immersion in 10% phosphate-buffered formalin, periodate-lysine-paraformaldehyde (PLP), Bouin's fluid, or absolute ethanol. Virus cultivation was also performed on parallel specimens, and the virus titer (TCID50/ml) was determined. Purified nucleocapsid protein (N-protein) of the virus was incorporated in an artificial antigen substrate (polymerized bovine serum albumin), fixed as described above, and embedded in paraffin wax. Microwave unmasking was performed on formalin-, PLP-, and Bouin's fluidfixed specimens. The presence of virus peptides in situ or N-protein in the artificial antigen substrates was visualized using an immunohistochemical method based on alkaline phosphatase or peroxidase and one polyclonal and five monoclonal polypeptide-specific antibodies. VHS virus was identified in situ in specimens with high virus titers (107–8 TCID50/ml) regardless of the fixative and without the need of an unmasking procedure. A pronounced masking effect was observed for the cross-linking formalin and PLP fixatives. Regardless of the primary antibodies used, there was a significantly higher epidemiologic sensitivity (the proportion of virus positive samples that tested positive by immunohistochemistry) using ethanol and Bouin's fluid compared with formalin and PLP ( P < 0.05). At 105 TCID50/ml, the average sensitivity reached 0.5, and at ≥106 TCID50/ml, sensitivity was 0.9. Unmasking procedures showed a moderate effect and did not result in significantly higher epidemiologic sensitivity ( P = 0.17). There was great variation for the different monoclonal antibodies/antigens and fixatives. Sensitivity studies on antigen substrates were in accordance with results of in situ studies that showed the highest sensitivity for ethanol and Bouin's fluid. Virus cultivation was more sensitive than immunohistochemistry. This study showed that the fixative and the primary antibody both influence method sensitivity and that VHS virus antigens concealed during fixation are difficult to reexpose. Immunostaining for VHS virus should be performed with monoclonal antibodies specific for the N-protein, and tissue samples should be fixed in either ethanol or Bouin's fluid. Immunohistochemistry is specific but is less sensitive than virus cultivation. Immunostaining for VHS virus can be a valuable supplement to virus cultivation during acute outbreaks of disease.
Pathogenicity of Cilia-associated Respiratory (CAR) Bacillus Isolates for F344, LEW, and SD Rats
Authors: Schoeb T. R. , Davidson M. K. , Davis J. K.
Published: January 2010

We conducted experiments to test whether rats of F344, LEW, and SD strains differ in susceptibility to mycoplasma-free isolates of cilia-associated respiratory (CAR) bacillus, whether Mycoplasma pulmonis can affect expression of CAR bacillus disease, and whether isolates of CAR bacillus differ in virulence for rats. In the first experiment, 24 rats of each strain were inoculated intranasally with 107 bacilli of CAR bacillus X1428D/AS, and 24 rats of each strain were inoculated with sterile medium (controls). Eight weeks later, eight inoculated rats and eight control rats of each strain were euthanatized, eight inoculated and eight control rats were given 106.5 colony-forming units of M. pulmonis X1428D, and eight inoculated rats and eight control rats were sham inoculated. Four rats of each group were euthanatized 4 or 8 weeks after the second inoculation. Severity of lesions in nasal passages, middle ear, trachea, and lungs was assessed by scoring. Rats of all three strains given CAR bacillus had typical lesions of similar severity; M. pulmonis X1428D was avirulent and did not exacerbate CAR bacillus disease. In the second experiment, groups of eight rats of F344 and SD strains were given 105 or 107 CAR bacillus X1328E, X1428D/AS, or X2450D and euthanatized 8 or 16 weeks later. Isolates X1428D/AS and X2450D caused similar lesions in rats of both strains and at both doses, but CAR bacillus X1328E was avirulent. Rats of the tested strains are similarly susceptible to CAR bacillus disease, but CAR bacillus isolates differ in virulence.
Light Microscopic, Immunohistochemical, and Electron Microscopic Features of Amyloid Arthropathy in Chickens
Authors: Peperkamp N. H. M. T. , Landman W. J. M. , Tooten P. C. J. , Ultee A. , Voorhout W. F. , Gruys E.
Published: January 2010

Amyloid arthropathy has been recently recognized as a spontaneous syndrome in chickens. Predominantly, femorotibial and tarsometatarsal joints were affected, showing (peri) articular orange amyloid deposits. Immunohistochemical evaluation revealed the amyloid to be of the reactive type. Induction of amyloid arthropathy in chickens was carried out using a single intravenous injection of Enterococcus faecalis cultures. In the naturally occurring and the induced cases, amyloid deposits were found in the hypertrophic synovial villi and in the articular cartilage, particularly in the superficial layer and in the nutritional blood vessel walls. Highly sulfated glycosaminoglycans (GAGs) were found in the amyloid deposits. Ultrastructurally, bundles of amyloid fibrils were seen in invaginations of synoviocytes and chondrocytes. Immunogold electron microscopy failed to reveal signs of intracellular amyloid formation. The predilection site for amyloid deposition in the major leg joints of the chickens with reactive amyloid could be explained by the arthritic condition caused by Enterococcus faecalis bacteriaemia. The polyarthritis triggers hepatic acute phase protein synthesis and increases the vascular serum amyloid A (SAA) supply to the joint. Inflammatory and degenerative changes in the articular cartilage and adjoining tissues result in an increase of highly sulphated GAGs, which are considered to enhance deposition of SAA as amyloid.
A Prospective Study of the Immunophenotype and Temporal Changes in the Histologic Lesions of Canine Demodicosis
Authors: Caswell J. L. , Yager J. A. , Parker W. M. , Moore P. F.
Published: January 2010

Mural folliculitis is a consistent histologic lesion of canine demodicosis. The objective of this study was to describe the immunophenotype and to evaluate temporal changes in histologic lesions of demodicosis during the course of therapy. Five dogs with demodicosis were examined and biopsied biweekly for up to 14 weeks; three dogs were evaluated once only. Lymphocyte subsets infiltrating the lesions were quantified using immunohistochemistry to detect CD3, CD21, CD4, and CD8 antigens. Lymphocyte subsets in blood were analyzed from four dogs using flow cytometry. Mural folliculitis was always present during clinically active disease. In contrast, following resolution of clinical lesions, perifolliculitis and/or perifollicular granulomas were present but mural folliculitis was absent. Most lymphocytes infiltrating the follicular epithelium in lesions of mural folliculitis were CD3+ and CD8+; the ratio of CD4+ : CD8+ cells in this epithelium was 0.032. In contrast, the perifollicular dermis contained approximately equal numbers of CD4+ cells and CD8+ cells, with slightly fewer CD21+B cells. In peripheral blood, the ratio of CD4+ : CD8+ lymphocytes was reduced and the percentage of CD8+ cells was increased in three of four dogs. These results indicate that mural folliculitis is a consistent lesion of clinically active canine demodicosis and is characterized by infiltration of the follicular epithelium by CD3+ CD8+ T lymphocytes. These lymphocytes are cytotoxic T cells, which may mediate the injury to the follicular epithelium in demodicosis. Alternatively, CD8+ T cells may play a role in resistance to Demodex canis infection or may represent a deleterious immune response in dogs that develop demodicosis.
Histologic, Immunohistochemical, and Polymerase Chain Reaction Studies of Bottlenose Dolphins from the 1987-1988 United States Atlantic Coast Epizootic
Authors: Schulman F. Y. , Lipscomb T. P. , Moffett D. , Krafft A. E. , Lichy J. H. , Tsai M. M. , Taubenberger J. K. , Kennedy S.
Published: January 2010

Tissues from 95 bottlenose dolphins ( Tursiops truncatus) that died during the 1987-1988 US Atlantic coast epizootic and 11 bottlenose dolphins that died along the Atlantic coast prior to 1987 were examined histologically and immunohistochemically. Polymerase chain reaction (PCR) testing was performed on 36 of the epizootic and all of the pre-1987 cases. Epizootic cases had syncytia and rare intranuclear and intracytoplasmic inclusion bodies within lung, lymph node, and spleen. Lymphoid depletion was present in lymph node, spleen, and gut-associated lymphoid tissue of epizootic cases. Pre-1987 cases did not have these pulmonary and lymphoid lesions. A larger percentage of epizootic than pre-1987 cases had bacterial and/or fungal infections (primarily pneumonias), pulmonary and lymphoid tissue histiocytosis, mucocutaneous ulcers, and evidence of negative energy balance. Immunohistochemically, 49/95 (52%) epizootic dolphins were positive for morbilliviral antigen. Morbilliviral antigen was detected in lung, lymph node, spleen, thymus, skin, tongue, esophagus, liver, pancreas, gastrointestinal tract, urinary bladder, oviduct, and mammary gland by immunohistochemistry. PCR testing identified morbilliviral RNA in 35/36 (97%) epizootic cases tested. Neither morbilliviral antigen nor morbilliviral RNA were detected in pre-1987 cases. Histologic, immunohistochemical, and PCR results provide strong evidence that morbillivirus infection was the primary cause of the 1987-1988 bottlenose dolphin epizootic.
Neuronal Vacuolation and Spinocerebellar Degeneration in Young Rottweiler Dogs
Authors: Kortz G. D. , Meier W. A. , Higgins R. J. , French R. A. , McKiernan B. C. , Fatzer R. , Zachary J. F.
Published: January 2010

With the recent epizootic of bovine spongiform encephalopathy in Europe, the differential diagnosis of neuronal vacuolation and spongiform change in other species has become critically important. Four Rottweiler puppies of both sexes, presented at 3-8 months of age, had clinical signs of generalized weakness and ataxia that started at 6 weeks of age. In all pups, neurologic examination detected an ataxia and tetraparesis, most severe in the pelvic limbs, and slowed proprioceptive placing reactions. Subsequently, there was rapid progressive neurologic deterioration, with severe placing deficits, knuckling, severe ataxia, and quadraparesis by 8 months of age. At necropsy, no gross lesions were observed. Microscopic lesions were restricted to the nervous system. The major lesion in all dogs was an intracytoplasmic neuronal vacuolation that was most prominent in the cerebellar roof nuclei and in nuclei of the extrapyramidal system. Similar vacuolation was found in neurons in both dorsal nerve root ganglia, myenteric plexus, and other ganglia of the autonomic nervous system. The single or multiple empty vacuoles were between 1 and 45 μm in diameter. A mild spongiform change was seen in the adjacent neuropil. Purkinje cell vacuolation and degeneration with segmental cell loss was seen in the oldest dog. In ventromedial and dorsolateral areas of the spinal cord white matter, there was mild bilaterally symmetrical axonal degeneration. Immunoblotting and immunocytochemical staining of the brain for protease-resistant scrapie prion protein was negative. All forms of vacuoles were negative for immunohistochemical staining with a variety of lectins. Ultrastructurally, the vacuoles were bound by a single membrane and contained granular material and sometimes membranous profiles. There was mild distension of the cytocavitary network but no unequivocal connection with the vacuoles was found. Axosomatic and axodendritic synapses in affected neurons were intact both ultrastructurally and with synaptophysin immunostaining. The clinicopathologic findings were different from those seen in the other neurologic diseases of Rottweilers. The age of the dogs, distribution and type of the lesions, ultrastructural findings, and negative immunoblotting most likely rule out the possibility of a scrapie agent-associated spongiform encephalopathy. However, the etiology of this new disease was not determined.
Immunohistochemical Staining Characteristics of Canine Gastrointestinal Stromal Tumors
Authors: LaRock R. G. , Ginn P. E.
Published: January 2010

Sections from 35 formalin-fixed, paraffin-embedded, canine gastrointestinal stromal tumors consisting of 14 leiomyomas (five stomach, three small intestine, two colon, four rectum), 18 leiomyosarcomas (one stomach, five small intestine, nine cecum, three rectum), two undifferentiated sarcomas (two stomach), and one neurofibrosarcoma (small intestine) were examined for the expression of vimentin, S-100 protein, α-smooth muscle actin, and desmin via immunoperoxidase methodology using an avidin-biotin complex technique. The leiomyomas were 4/14 (29%) vimentin-positive, 3/14 (21%) S-100 protein-positive, 10/14 (71%) α-smooth muscle actin-positive and 13/14 (93%) desmin-positive. Leiomyosarcomas were 18/18 (100%) vimentin-positive, 11/18 (61%) S-100 protein-positive, 9/18 (50%) α-smooth muscle actin-positive, and 15/18 (83%) desmin-positive. The undifferentiated sarcomas were 2/2 (100%) vimentin-positive, 2/2 (100%) S-100 protein-positive, 1/2 (50%) α-smooth muscle actin-positive, and 0/2 (0%) desmin-positive. The neurofibrosarcoma was vimentin and S-100 protein-positive and α-smooth muscle actin- and desmin-negative. Thirty-one of thirty-five (89%) of all neoplasms demonstrated reactivity for either desmin and/or α-smooth muscle actin. S-100 protein reactivity occurred in 17/35 (49%) of all specimens. Lack of desmin and α-smooth muscle actin reactivity occurred in 4/35 (11%) of all specimens, all of which were vimentin-positive. The immunohistochemical results indicate that the majority of canine gastrointestinal stromal tumors (GIST) with light microscopic features of smooth muscle cells have immunohistochemical staining patterns supporting smooth muscle differentiation. Vimentin reactivity correlated with a light microscopic diagnosis of malignancy. The lack of smooth muscle cell markers in some tumors and the high percentage of cases positive for S-100 protein may suggest a more complex histogenesis or differentiation for subgroups of these tumors.
Lesions of Experimental Equine Morbillivirus Pneumonia in Horses
Authors: Hooper P. T. , Ketterer P. J. , Hyatt A. D. , Russell G. M.
Published: January 2010

Laboratory examinations of equine morbillivirus included experimental reproductions of the disease caused by the virus by transmission of mixed lung and spleen taken from two field equine cases into two horses and by inoculating tissue culture virus into a further two horses. The most distinctive gross lesions of the diseases that developed in three of the horses was that of pulmonary edema characterized by gelatinous distension of subpleural lymphatics. Histologically, the lesions in the lungs were those of serofibrinous alveolar edema, alveolar macrophages, hemorrhage, thrombosis of capillaries, and syncytial cells. Clearly defined vascular lesions in three horses that became clinically affected within 8 days of inoculation of virus included intramural hemorrhage, edema, and necrosis and syncytial cells in the endothelium of pulmonary vessels (∼40-70 μm in diameter). Vascular lesions accompanied by parenchymal degeneration were also seen in the heart, kidney, brain, spleen, lymph node, and stomach. A fourth horse, which survived for 12 days, had detectable lesions only in the lungs, which were more chronic than those in the other three horses, a greater degree of cellular infiltration, and fewer well-defined vascular lesions. Sections stained by an indirect immunocytochemical method showed equine morbillivirus antigen was present in the vascular lesions and along alveolar walls. When endothelial cells were examined by electron microscope, cytoplasmic virus inclusion bodies containing filamentous structures were seen that reacted to an immunogold test to equine morbillivirus antigen. The presence of the syncytia in the small blood vessels in the lungs and other organs was interpreted as an important characteristic of the disease and consistent with a reaction to a morbillivirus.
The Lesions of Experimental Equine Morbillivirus Disease in Cats and Guinea Pigs
Authors: Hooper P. T. , Westbury H. A. , Russell G. M.
Published: January 2010

Nine cats and four guinea pigs became affected with severe disease during experiments on the infectivity of equine morbillivirus, a newly recognized cause of respiratory disease in horses and humans. Four of the cats were challenged by subcutaneous inoculation, two by intranasal installation, two by oral dosage, and one by direct contact with a cat previously infected by subcutaneous inoculation. All four guinea pigs were inoculated subcutaneously. Gross pathology seen in all affected cats was characterized by hydrothorax and dark, heavy, wet, congested and/or hemorrhagic lungs with froth sometimes found in the respiratory passages. Pulmonary lymph nodes were enlarged and edematous. Six cats also had congested ceca with accompanying edema of mesenteric lymph nodes. Histologically, the lesions in the lungs of the cats were those of severe interstitial pneumonia characterized by serofibrinous alveolar edema, alveolar macrophages, intra-alveolar hemorrhage, thrombosis of small veins, alveolar wall necrosis, and syncytial cells. Clearly defined vascular lesions included intramural hemorrhage, edema, and necrosis and syncytial cells in the endothelium of pulmonary arteries and veins, 20-80 μm in diameter. Vascular lesions accompanied by parenchymal degeneration were also seen in the gastrointestinal and lymphoid organs. Syncytial cells were also visible in the lymphoid tissues of lymph nodes, spleen, and Peyer's patches. At necropsy, all guinea pigs were cyanosed and had congestion and edema in the gastrointestinal tract. Histologically, there was widespread vascular disease in arteries and veins, 20-80 μm in diameter, in many organs such as the lungs, kidneys, spleens, lymph nodes, gastrointestinal tracts, and skeletal and intercostal muscles, but there was no severe pulmonary edema as seen in horses and cats. Sections of tissues of the cats and guinea pigs, examined by indirect immunocytochemical stains, confirmed that the vascular damage was associated with the presence of equine morbillivirus antigen. The syncytia in small blood vessels in the lungs and other organs of both cats and guinea pigs were similar to those seen in horses, and their presence was interpreted as an important characteristic of the disease consistent with a reaction to a morbillivirus.
Experimentally Induced Selenosis of Adult Mallard Ducks: Clinical Signs, Lesions, and Toxicology
Authors: O'Toole D. , Raisbeck M. F.
Published: January 2010

Selenosis is thought to be a significant problem among waterfowl populations in selenium-contaminated wetlands in the western United States. Chemical analysis of avian tissues is currently the principal basis for diagnosis. The purpose of these two 150-day studies was to establish whether morphological criteria for selenosis could be developed to supplement chemical analysis. Forty-eight flightling male mallard ducks were fed either a proprietary waterfowl ration (< 1 ppm selenium) or the same ration amended to contain 10, 25, and 60 ppm selenium supplied as seleno-L-methionine ( n = 12/group). In a separate study, 12 birds fed twice daily were offered either a proprietary ration or a selenium-supplemented ration (120 μg/g) for one of two daily feedings. Selenium in whole blood increased from baseline concentrations (< 0.4 μg/ml) to means of 4.5, 8.9, and 16.0 μg/ml in the 10-, 25-, and 60-ppm groups, respectively. All birds in the 60-ppm-dose group rapidly lost weight and were killed (11/12) or died (1/12) between 22 and 50 days of dietary exposure. In addition to emaciation, six of 12 birds (50%) fed the 60-μg/g diet developed mild to moderate generalized hepatopathy with single-cell necrosis, karyomegaly of hepatocytes, hyperplastic bile duct epithelium, and/or iron accumulation in Kupffer cells. The principal lesions in birds exposed to other dietary concentrations of selenium involved integumentary structures containing hard keratin. Gross lesions developed after 76 days of dietary exposure and consisted of bilaterally symmetrical alopecia of the scalp and dorsal cervical midline, broken or lost digital nails, and necrosis of the tip of the beak (maxillary nail). One or more of these three lesions were present in 0/12 birds (0%) fed 10 ppm selenium, 5/12 birds (42%) fed 25 ppm selenium, and 4/9 (44%) birds fed a split-feed diet containing 120 ppm selenium. Controls were unaffected. Histologic lesions in digital and maxillary nails consisted of single-cell to full-thickness necrosis of keratinocytes and multifocal parakeratosis in stratum corneum. Histologic lesions in alopecic skin (necrosis of the epidermal collar, inflammation of the feather pulp, and follicular keratosis) were mild. Some birds with alopecia had no detectable lesions in feather follicles from affected areas of skin. The highest tissue concentrations of selenium were in liver, kidney, and feathers, respectively. Mean hepatic tissue concentrations were 14.5 μg/g (10 ppm group), 29.6 μg/g (25 ppm group), 60.6 μg/g (60 ppm group), 13.0 μg/g (120 ppm split-feed group), and 2.0 μg/g (controls). Integumentary and hepatic lesions may be of value in corroborating a diagnosis of selenosis based on chemical analysis of tissues from naturally intoxicated waterfowl. Some birds with fatal selenosis may have no morphologic lesions other than emaciation.
Idiopathic Myelofibrosis (Agnogenic Myeloid Metaplasia) in a Marmoset (Callithrix jacchus): Hematologic and Histopathologic Changes
Authors: Khan K. N. M. , Logan A. C. , Blomquist E. M.
Published: January 2010

Idiopathic myelofibrosis (IMF), or agnogenic myeloid metaplasia, was diagnosed in a sexually mature male marmoset { Callithrix jacchus) based on the results of hematology and histopathologic evaluation of the bone marrow. The hematologic changes included pancytopenia, leukoerythroblastosis, anisocytosis, poikilocytosis, and giant platelets. Histopathologic evaluation of the bone marrow showed marked widespread fibrosis replacing hematopoietic cells and the presence of atypical megakaryocytes. In addition, slight multifocal osteolysis with an increase in serum alkaline phosphatase activity was observed. We believe this is the first report of IMF in a nonhuman primate species.
S-100 Immunoreactivity in Melanomas of the South American Opossum Monodelphis domestica
Authors: Kusewitt D. F. , Miska K. B. , Ley R. D.
Published: January 2010

S-100 immunoreactivity was determined 1) in foci of melanocytic hyperplasia, 2) in naturally occurring, ultraviolet radiation-induced, and 9,10-dimethyl-1,2-benzanthracene (DMBA)-induced primary melanomas, and 3) in metastatic melanoma lesions in the South American opossum Monodelphis domestica. Preneoplastic lesions of melanocytic hyperplasia contained scattered cells with S-100-positive nuclei. All primary melanomas, with the exception of a single DMBA-induced tumor, contained cells with S-100-positive nuclei. The pattern of S-100 reactivity in tumors varied from large foci of S-100-positive cells to scattered individual S-100-positive cells. Lymph node metastases were S-100 positive, but metastatic masses in internal organs were usually S-100 negative. Although S-100 reactivity did not distinguish preneoplastic lesions from tumors or benign melanomas from malignant melanomas, identification of metastatic tumor cells clearly demonstrated malignancy.
Trombidiosis-induced Dermatitis in White-tailed Deer (Odocoileus virginianus)
Authors: Little S. E. , Carmichael K. P. , Rakich P. M.
Published: January 2010

During a routine blood collection at a wildlife management checkpoint, several white-tailed deer { Odocoileus virginianus) from Lake Russell Wildlife Management Area, Habersham County, Georgia, were observed to have accumulations of orange granular material around the eyes and mouth accompanied by serous exudate, crusting, and alopecia. Microscopic examination of the granular material disclosed numerous larval mites of the family Trombiculidae. Histologic examination revealed severe chronic diffuse plasmacytic dermatitis with intralesional larval trombiculid mites. Several stylostomes were also identified in the tissue sections. This paper describes the gross and histologic changes associated with severe trombiculid infestation in a white-tailed deer and suggests potential causes for this unusual finding.
Bilateral Renal Metastases of Nasal Chondrosarcoma in a Dog
Authors: Hahn K. A. , McGavin M. D. , Adams W. H.
Published: January 2010

Chondrosarcoma is the most common nonepithelial sinonasal neoplasm in the dog, and metastasis is considered rare. A 7-year-old Irish Setter had bilateral renal enlargement 17 months following surgery and radiotherapy for a primary nasal chondrosarcoma. Histologic evaluation revealed chondrosarcoma metastases in both kidneys. A diagnosis of nasal chondrosarcoma with bilateral renal metastasis was made. The clinical importance of this report is that routine recommendations for the evaluation of regional and/or distant metatasis in a dog with a dignosis of nasal chondrosarcoma, namely routine whole body physical examination and thoracic radiography, failed to demonstrate the presence of abdominal metatases, which ultimately led to the demise of this dog. The biologically aggressive nature of this chondrosarcoma of the nasal cavity indicates that additional information is needed before a prognosis can be reliably established for dogs with this tumor type.
Immunohistochemical Localization of Parathyroid Hormone-related Protein in Canine Mammary Tumors
Authors: Okada H. , Nishijima Y. , Yoshino T. , Gröne A. , Capen C. C. , Rosol T. J.
Published: January 2010

Parathyroid hormone-related protein (PTHrP) was localized immunohistochemically in 58 canine mammary tumors (31 malignant, 27 benign) and adjacent normal or hyperplastic mammary tissue. PTHrP immunoreactivity was significantly enhanced by pretreatment with microwave heating in normal and neoplastic tissues. Epithelial cells of hyperplastic and neoplastic mammary tissues, myoepithelial cells, and metaplastic osteoblasts in mammary tumors stained moderately to strongly positive for PTHrP. No significant difference between staining intensity for PTHrP and histologic pattern of mammary tumors was found. The presence of PTHrP in normal and neoplastic canine mammary tissues supports a pathophysiological role for PTHrP as a paracrine or autocrine hormone in the mammary gland.
Rhabdoid Tumor in the Brain of a Dog
Authors: Steele K. E. , Schulman F. Y. , Mena H. , Strimple E. O.
Published: January 2010

Rhabdoid tumor is a neoplasm of uncertain cellular origin recognized in humans. These tumors most commonly arise in the kidneys of children, but they can also affect many extrarenal sites, including the central nervous system. Similar neoplasms have not been reported in nonprimate species. A malignant brain tumor in a young dog was characterized by large cells with globular intracytoplasmic inclusions composed of intermediate filaments. By immunohistochemistry, neoplastic cells were uniformly reactive for vimentin and demonstrated scattered reactivity for glial fibrillary acidic protein and neuron-specific enolase. The intermediate filaments also reacted with vimentin antibodies by immunogold electron microscopy. The findings in this case are remarkably similar to the histologic, ultrastructural, and immunocytochemical features of rhabdoid tumors in humans.
Mechanisms of Echinocytosis Induced byCrotalus atroxVenom
Authors: Walton R. M. , Brown D. E. , Hamar D. W. , Meador V. P. , Horn J. W. , Thrall M. A.
Published: January 2010

Transient echinocytosis has been reported in association with snake envenomation in humans and dogs. An in vitro model of echinocytosis induced by venom of Crotalus atrox (western diamondback rattlesnake) was established to characterize erythrocyte morphologic changes and to investigate potential mechanisms of echinocytic transformation. Erythrocyte morphologic changes produced after the addition of venom to canine, feline, equine, and human blood were characterized by dose-dependent echinocytosis. Type III echinocytosis was consistently induced in vitro at a dose comparable to in vivo envenomation; higher venom doses produced spheroechinocytic and spherocytic transformations. These changes could not be induced in vitro in the presence of ethylenediaminetetraacetic acid but were observed in heparinized and citrated blood samples, suggesting the participation of calcium or a metalloprotein in echinocytic change. These findings suggest that phospholipase A2 (PLA2), a calcium-dependent enzyme in snake venom, may be responsible for echinocytic transformation via the production of lysolecithin, a known echinocytic agent. Purified PLA2 from C. atrox venom induced dose-dependent echinocytic change in vitro in canine blood. Other potential mechanisms of echinocytic change evaluated in canine blood included erythrocyte cation loss and erythrocyte ATP depletion. In canine blood mixed with venom, erythrocyte sodium and potassium concentrations were consistently less than those of controls, likely as a result of membrane alterations produced by the actions of PLA2. There was no difference in blood ATP concentrations from dogs with snakebite when compared with normal controls; however, the power of this comparison was low. Echinocytosis induced by rattlesnake venom is related to the degree of venom exposure and may correlate clinically with the amount of venom absorbed. Echinocytic transformation in vitro is induced by PLA2 present in venom.
Porcine Reproductive and Respiratory Syndrome
Authors: Rossow K. D.
Published: January 2010

In 1987, porcine reproductive and respiratory syndrome (PRRS) was recognized in the USA as a new disease of swine causing late-term reproductive failure and severe pneumonia in neonatal pigs. The syndrome is caused by an RNA virus referred to as PRRS virus (PRRSV), which is classified in the family Arteriviridae. Swine macrophages are the only indigenous cell type known to support PRRSV replication. Direct contact between infected and naive pigs is the predominant route of PRRSV transmission. Exposure of a mucosal surface to PRRSV leads to virus replication in regional macrophages, a prolonged viremia and systemic distribution of virus to other macrophage populations. Reproductive failure induced by PRRSV infection in late-gestation sows is characterized by premature farrowing of stillborn, partially autolyzed, and mummified fetuses. Pneumonia caused by PRRSV infection is more severe in young pigs compared to adults and may be complicated by concurrent bacterial infections. Gross lung lesions associated with PRRSV infection vary from none to diffuse consolidation. In addition, multiple lymph nodes may be markedly enlarged. Microscopically, PRRSV-pneumonia is characterized by multifocal, interstitial thickening by macrophages and necrotic cell debris in alveoli. Other less common microscopic lesions of PRRSV infection include myocarditis, vasculitis, encephalitis, and lymphoid hypertrophy and hyperplasia. In acute or subacute PRRSV infections, serum and lung are the best specimens for diagnosis. Persistent PRRSV infections can be produced by transplacental or intranasal infection. Persistent PRRSV infections are an important factor for virus survival and transmission within a swine herd and will complicate control programs.