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Background: The navicular syndrome may be associated with alterations in other podotrochlear apparatus components, such as the deep digital flexor tendon, collareral sesamoid and distal sesamoid ligaments, podotrochlear bursa and distal sesamoid bone. However, the clinical significance and nature of these changes are not well understood, many of descriptive reports about distal sesamoid bone lesions are rarely accompanied by a complete and comprehensive comparison with animals of the control group. The aim of this study was to described histologically findings of the podrotrochlear apparatus components, allowing the understanding of the inserts and their microscopic appearance, thus providing the future recognize of their alterations. Materials, Methods & Results: Fourteen samples of the podotrochlear apparatus were taken out of 44 equine thoracic limbs specimens, separated at the radiocarpal joint of Crioulo and Thoroughbred horses, with an average age of 6.0-year-old, coming from a private clinic in southern Brazil. The thoracic limbs specimens were refrigerated at 4ºC at the clinic and then they were sent to the University Federal of Santa Maria (UFSM). Once at the University laboratory, the specimens were dissected to isolate the podotrochlear apparatus from each one. Subsequently, transversal and longitudinal samples from the distal sesamoid bone, deep digital flexor tendo, distal sesamoid ligament, colateral sesamoid ligament, were collected and podotrochlear bursa which were processed at the Veterinary Pathology Laboratory of the UFSM and University Federal of Santa Catarina (UFSC). The tissues samples were fixed in a 10% formaldehyde solution for 14 days and routinely processed for histology. The samples were sectioned at 3 µm and stained using the hematoxylin-eosin (H-E) routine method. The bone samples, after fixation, underwent a decalcified process in a formic acid-sodium citrate aqueous solution and routinely processed for histopathology. Histologic tendons evaluation showed that it is arranged in honeycombs fascicles in a transverse section observation. The tendinous fibers have a more compact and aligned collagen fibers arrangement due to the dense connective tissue. The synovial membrane of the podotrochlear bursa is composed of a cubic pseudo conjunctival epithelium arranged with a layer of synoviocytes forming villi towards the lumen. This characterization is very similar to that of the synovial joint membrane. The collateral sesamoid ligament fibers are not perfectly aligned, occurring at their confluence in some areas accompanied by the dissection of adipose tissue. The distal sesamoide ligament fibers, composed by of loose connective tissue associated with synoviocytes and vascular stroma. The articular surface of the distal sesamoid bone is arranged in 3 layers of chondrocytes embedded in a hyaline matrix. There was a clear differentiation between the subchondral bone area and the fibrocartilage tissue in the palmar aspect of the distal sesamoid bone. Discussion: The morphophysiological characterization of the podotrochlear structures inside the hoof capsule it is important for the future recognition of abnormalities and the possible hypothesis that originates the podotrochlear syndrome. These changes have great clinical relevance and very often associated of distal limb lameness in horses. The normal macroscopic, ultrasonographic and radiographic images along with the histomorphometric study of the podotrochlear structures have contributed for the morphophysiological comprehension and consequently future interpretation of the podotrochlear structures diseases. [ABSTRACT FROM AUTHOR]

Background: Candida spp. are pleomorphic fungi that are commensal inhabitants of the oral, gastrointestinal, upper respiratory and urogenital mucosa of mammals. Candida albicans is described as the most important species. This opportunistic pathogen may produce local or systemic infections in dogs. Local infections have been reported in several tissues and systemic infection is rare in dogs with few reports in the literature describing this presentation. The aim of the present study was to report two cases of cerebral Candida albicans infection in dogs in Brazil. Case: Two cases of cerebral Candida albicans infection in dogs that showed nervous signs are described. In both cases, the brain showed marked asymmetry of the telencephalic hemispheres with multifocal to coalescing yellowish or reddish areas and a partial loss of distinction between gray and white matter. In Case 1, the mediastinal, tracheobronchial and mesenteric lymph nodes, as well as the right kidney and adrenal gland, showed altered architecture due to numerous whitish gray nodules. Histological lesions were characterized by granulomatous (case 1) or pyogranulomatous (case 2) necrotizing meningoencephalitis with intralesional fungal organisms. In case 1, similar granulomatous infiltrate with intralesional fungal organisms was also seen in the lymph nodes, kidney and adrenal gland. In case 2, there was evidence consistent with an underlying infection of canine distemper virus. Were observed lymphoplasmocytic interstitial pneumonia, lymphoid rarefaction in lymph nodes, and viral intracytoplasmic inclusion bodies in the epithelial cells of the stomach and vesical urothelium. In these two cases, the fungal organisms displayed three different morphological patterns. The first pattern was characterized by delicate tubular structures with thin parallel walls that were rarely septate and tended to undulate slightly, and measured approximately 4-20 µm (true hyphae). The second pattern was characterized by chains of elongated yeast, separated by constrictions at septal sites, and measured approximately 4-10 µm (pseudohyphae). The other morphological pattern, which was rarely observed, was characterized by round budding yeast cells that measured 3-4 µm in diameter and were often elongated by the germ tube. Sections were also stained using immunohistochemical antibodies against Candida albicans. The fungi revealed strong immunolabelling of the cytoplasm and wall for Candida albicans. Discussion: The diagnosis was based on the histomorphological and immunohistochemical characteristics of the agent, which were consistent with Candida albicans. In these two cases, immunocompromise appeared to have been an important factor in the progression of the infection. In case 1, the dog was senile and treated with corticosteroids, conditions that could effectively limit innate, humoral and cell-mediated immune response to infection. In case 2, the dog displayed cachexia and was infected by canine distemper virus, evidenced by the presence of viral inclusion bodies. The inflammatory reactions in both cases were characteristic of fungal infections, but were distinct due to differences in the infectious process. In case 1, there was a subacute to chronic progression; while in case 2 neutrophilic infiltrate predominated, suggesting an acute progression. The different morphological patterns of the fungi suggested a pleomorphic fungi and the immunohistochemistry allowed us to identify the infectious agent. In conclusion, opportunistic infections caused by Candida albicans should be considered when diagnosing diseases that affect the central nervous system of dogs, particularly in immunosuppressed animals. [ABSTRACT FROM AUTHOR]

Background: Mammary gland carcinoma is a malignant epithelial neoplasm that can be classified as solid, papillary, ductal, invasive micropapillary, or invasive ductal. They are rarely diagnosed in livestock animals. Reports describing the breast as primary site of tumor in cows are scarce. In this case report, pathological and clinical findings of primary carcinoma of the mammary gland in a cow are reported. Case: A 7-year-old crossbred pregnant cow exhibited an increase in volume in the posterior region of the udder. Palpation raised suspicion of mastitis. The prefemoral lymph nodes (LNs) were enlarged. After calving, the clinical condition worsened, and edema was observed in the ventral region, from the udder to the neck. Poisoning by Amaranthus sp. was suspected. The cow died fifteen days after calving. Necropsy was performed. The affected mammary gland and its LNs, fragments of abdominal organs, brain, pelvic limbs, and udder skin were routinely prepared and stained with hematoxylin and eosin. Gross examination revealed significant alterations in the mammary gland, and in the mammary and prefemoral LNs. The mammary gland was firm and swollen; with loss of normal architecture, and released purulent, pinkish, fetid contents. The mammary LNs were enlarged, with diffuse coalescent multifocal lesions, loss of corticomedullary delimitation, and the content was similar to that observed in the udder. The internal prefemoral LNs were also enlarged and contained the same fetid contents. Histopathology revealed proliferation of neoplastic ducts coated by numerous neoplastic cells; some areas were solid. There was moderate to severe pleomorphism, with moderate anisocytosis and anisokariosis. Most of the cells had vesicular nuclei, with up to two evident nucleoli. Other cells had dense chromatin, and moderately eosinophilic cytoplasm. There was marked cell dissociation, and cell detachment. The central portions of the ducts were necrotic, with a predominantly neutrophilic inflammation. The mitotic index was low, but some areas had up to four mitotic figures per high power field. Numerous areas exhibited multiple foci of deposition of organized granular basophilic material, interpreted as mineralized areas, and stained positively for Von Kossa stain. Some areas of the mammary gland exhibited proliferative acini and ducts, composed of a single layer of cuboidal or columnar cells with moderately eosinophilic, vacuolated cytoplasm, and a basal rounded nucleus of generally aggregated chromatin (mammary hyperplasia). Many acini were dilated, and some contained circumscribed basophilic material (corpora amylacea). The structural architecture of the LNs was altered by malignant neoplastic infiltration, similar to that found in the mammary gland. No metastatic lesions were detected in the other organs. Immunohistochemistry (IHC) was performed using the streptavidin-biotin-peroxidase technique. Anti-pan-cytokeratin and antivimentin antibodies were used. Neoplastic cells exhibited strong and uniform cytoplasmic immunoreactivity for pan-cytokeratin. Expression of vimentin was absent in the neoplastic cells, but was present in the connective tissue associated with the neoplasm. Discussion: Invasive ductal mammary carcinoma was confirmed by histopathological and IHC analyses. Edema can be explained by the neoplasm in the mammary gland and in the mammary LNs, with accumulation of fluid in the interstitium, caused by growth of the tumor and compression of large blood and lymphatic vessels. IHC confirmed the epithelial origin of the tumor and demonstrated the presence of epithelial tumor cells in the LNs, proving to be metastatic. Similar findings were reported in a cow with a highly aggressive secretory mammary carcinoma, in which neoplastic cells exhibited immunoreactivity to cytokeratin, indicative of their epithelial origin. [ABSTRACT FROM AUTHOR]

Background: The injury repair process in tendons and ligaments includes different phases such as inflammation, neovascularization, fibroblast proliferation and fibrosis. Collagen type and tissue characteristics of tendon and ligament repair are described such as type collagen differentiation and properties of the scars tissue. The degeneration of articular cartilage when, characterized by loss of the articular layers associated of the decreased of proteoglycans. The aim of this study is to describe by histochemistry techniques the characteristics of tissue scar, collagen type in the repair process of tendons and ligaments, as well as articular cartilage degeneration. Materials, Methods & Results: Tissue samples of equine tendons, ligaments and articular cartilage of the metacarpophalangeal joint region were evaluated by ultrasonography, macroscopically and prepared for routine histopathology (H&E staining). The inclusion criterion of the samples in this study was based on the presence of lesions characterized in H&E stain as fibroplasia, neovascularization, collagenolysis, chondroid metaplasia in tendons and ligaments and fibrillation and cartilaginous eburnation lesions in the articular cartilage samples. The Masson's trichrome, Picrosirius red and Alcian blue staining techniques were also performed in addition to H&E. Pathologic findings in the tendons and ligaments included fibroplasia, collagenolysis, chondroid metaplasia and lymphohistioplasmacytic inflammation. Tendons and ligaments scars were composed of type III collagen but there was also some type I collagen. Fiber alignment of tendons and ligaments in the reorganization tissue was not flawless and the fiber appearance was characterized by a lack of the fiber crimp and parallelism. The fibroplasia was characterized by endotendinous tickening areas associated with the presence of loose connective tissue. In the areas of loose connective tissue substitution, collagen type fibers are intercalated to a lesser extent by type-III collagen fibers. In the Alcian blue stained samples of articular cartilage observed the surface layer and the matrix zone of calcified cartilage were weakly stained in blue. Discussion: Three special stains were utilized in this study along with the H&E evaluation elucidating the behavior tendons, ligaments and articular cartilage injury. The important observation in this study was fibroplasia in tendons and ligaments seems to be composed by abundant of loose connective tissue, chondrocytes and intermingled collagen type I and III fibers associated with lack of crimps alignment of the fibers. The fragile structure suggested by the Masson's trichrome stain results (presence of the loose connective tissue) in this study perhaps make the tendons and ligaments receptive to other lesions. The characteristic blue discoloration of collagen fibers was only observed in the loose connective tissue may be because the dye penetration becomes easier when compared to the dense connective tissue (stained in red). The Masson's trichrome made possible the differentiated the dense connective tissue of the loose connective tissue. The combined histochemistry staining technics allowed an improved characterization of fiber alignment, collagen type, inflammatory cell infiltration and neovascularization, which happens during the repair process of tendons and ligaments. The fibrillation and eburnation of the articular cartilage were associated with the decrease Alcian Blue staining characterized by degeneration process of articular cartilage. [ABSTRACT FROM AUTHOR]

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Copyright of Archives of Veterinary Science is the property of Archives of Veterinary Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Tumor embolization is a well-described cause of unexpected death in human oncologic patients; however, it is poorly explored in veterinary medicine. We report a case of pulmonary tumor embolization in a dog with sudden death. During necropsy, a neoplastic mass was observed replacing the left adrenal gland and forming an intravascular thrombus within the central adrenal vein. A large embolus occluded the left pulmonary artery. The adrenal mass was histologically confirmed as a pheochromocytoma, and the embolus was constituted of neoplastic cells. Multiple smaller neoplastic emboli were observed within the pulmonary artery branches. Tumor embolization should be considered as a possible cause of sudden death in dogs, particularly in oncologic patients [ABSTRACT FROM AUTHOR]

A case of meningoencephalitis caused by Pythium insidiosum secondary to rhinitis is reported in a three-year-old crossbred sheep from a herd of 15 animals, raised extensively and with free access to a weir. The animal presented mild dyspnea, blindness, mydriasis, opisthotonos, nystagmus, incoordination, decreased mandibular tone, and spasticity of the pelvic limbs. Macroscopic examination of the nasal cavity showed a blackish-red, irregular, friable mass that bilaterally compromised the nasal septum and the rostral portion of the nasal turbinates. In the brain, there was diffuse thickening of the leptomeninges of the cerebellum and ventral portion of the brainstem characterized by yellowish, granular material associated with vessel hyperemia. On the floor of the fourth ventricle, there was deposition of yellowish, irregular, slightly granular material that protruded towards the obex and displaced the cerebellum dorsolaterally. Microscopically, there were pyogranulomatous, eosinophilic, necrotizing rhinitis and fibrinosuppurative, eosinophilic, necrotizing meningoencephalitis, both associated with thrombosis, vasculitis, and intralesional hyphae. The hyphae were impregnated with silver and presented thin, parallel walls, rarely septate and branched. At immunohistochemistry, the hyphae were immunostained with polyclonal anti-P. insidiosum antibody in fragments of the cerebellum and nasal cavity. The findings showed that P. insidiosum rhinitis can secondarily affect the nervous system of sheep, causing nonspecific neurological clinical signs. [ABSTRACT FROM AUTHOR]

This report aimed to describe the clinical, epidemiological and pathological aspects of an outbreak of rabies in buffaloes in Rio Grande do Sul (RS), Brazil. Seven out of 41 buffaloes from the same farm became fatally ill; they showed the clinical signs of ataxia, ascending paresis, and paralysis of the limbs. During necropsy, marked hyperemia of the leptomeningeal vessels, and severe distention of the urinary bladder were noted. Histologically, there were indications of nonsuppurative meningoencephalitis and ganglioneuritis with intracytoplasmic and eosinophilic inclusion bodies in the neurons. The fluorescent antibody test was positive for rabies. Viral antigens were also detected by immunohistochemistry (IHC) in sections of the cerebellum. These results allowed for the definitive diagnosis of rabies, which is uncommonly reported in buffaloes. [ABSTRACT FROM AUTHOR]

This case report describes the clinical, histopathological and immunohistochemical findings in two dogs with myelopathy associated with metastasis of follicular-compact thyroid carcinoma. Microscopically, both primary neoplasms were characterized by polygonal cells arranged in follicles (occasionally filled with eosinophilic colloid-like material) or in sheets. The neoplastic cells had a moderately eosinophilic cytoplasm and there was moderate anisokaryosis and anisocytosis. Additionally, the neoplastic cells were positive for thyroglobulin on immunohistochemistry, confirming the follicular origin of both tumors. This is a very uncommon presentation of this pathological condition. [ABSTRACT FROM AUTHOR]