Evaluation of the common pauraque (Nyctidromus albicollis) cornea using light and scanning electron microscopy.

The common pauraque Nyctidromus albicollis (Gmelin, 1789) is a widespread avian species; however due to its nocturnal habits and reclusive behaviour, little is known about their vision and ecology. Most avian species are visually dependent with advanced visual systems providing high spatial resolution, on the species needs. Each ocular structure has a specific role in contributing towards high visual function, and the cornea is the first refractive structure in the visual process. However, the common pauraque cornea had not been described until the present data. Therefore, this study aims to describe the morphology and morphometry of the common pauraque cornea by means of light and scanning electron microscopy to evaluate the cross-sectional anatomy as well as the ultrastructure of the endothelial cells. Histological similarities with the cornea of other birds have been observed, but the thickness of the common pauraque cornea is much smaller than the other described corneas. A better understanding of the common pauraque cornea can help us better explain the physiology of vision and the visual requirements of this species. In turn, this will help us better understand how this species successfully interacts with its environment, and will improve our knowledge on how to interpret pathological changes in their cornea in a clinical setting.

Canine and feline uveal melanocytic tumours: Histologic and immunohistochemical characteristics of 32 cases.

OBJECTIVE: Gross, histopathological, and immunohistochemical characteristics of uveal melanocytic neoplasms in dogs and cats were investigated. SAMPLES: Thirty-two enucleated globes with uveal melanocytic neoplasms, 27 from dogs and 5 from cats, were examined. PROCEDURES: Morphological characteristics of uveal melanocytic neoplasms in dogs and cats were evaluated with anti-PNL2, anti-Melan-A, anti-Ki-67, anti-caspase-3, and anti-BAP1 immunomarkers. Statistical analysis was performed to compare canine melanocytomas and melanomas. RESULTS: The 32 uveal neoplasms were classified as melanocytomas (19/27 in dogs) or melanomas (8/27 in dogs, 5/5 in cats). Most tumours (84%) were located in the anterior uvea. Neoplastic cells were classified as epithelioid, spindle-shaped, mixed, or special type (balloon and signet ring cells). The percentage of cells with melanin, melanin concentration within cells, anisocytosis and anisokaryosis, mitotic count, lymphocytic inflammation, necrosis, vascular invasion, and glaucoma were also characterized. Anisocytosis, percentage of neoplastic cells with melanin, mitotic count, and indices (proliferation and apoptotic) varied significantly between canine uveal melanomas and melanocytomas; in general, melanomas had greater cell variability, were less pigmented, and had a higher mitotic count. The melanocytic origin of the neoplasms was confirmed by positive anti-PNL2 immunolabelling (29/32) and positive anti-Melan-A immunolabelling (3/32). In canine uveal melanomas, anisocytosis and anisokaryosis correlated with less pigmentation and minimal pigmentation correlated with a high percentage of immunolabelling for caspase-3. CONCLUSIONS: Uveal melanocytomas were more common in dogs, and uveal melanomas were more frequent in cats. Anisocytosis, percentage of neoplastic cells with melanin, and mitotic count are important histologic characteristics of malignancy to evaluate in uveal melanocytic neoplasms. The proliferation and apoptotic indices are relevant when comparing malignant tumours with benign tumours.

Molecular detection, histopathological analysis, and immunohistochemical characterization of equine infectious anemia virus in naturally infected equids.

Equine infectious anemia (EIA), a disease caused by equine infectious anemia virus (EIAV), is considered an obstacle to the development of the horse industry. There is no treatment or vaccine available for EIA, and its pathogenesis, as well as the immune response against the virus, is not fully understood. Therefore, an immunohistochemistry assay was developed for the detection of viral antigens in tissues of equids naturally infected with EIAV. Sections of organs of six equids from Apodi-RN, Brazil, that tested positive for EIA by serological tests (ELISA and AGID) were fixed in 10% formalin solution and embedded in paraffin. Immunohistochemistry was performed using a polyclonal anti-EIAV antibody. EIAV antigens were observed in red spleen pulp cells and hepatic sinusoids, as well as bronchiolar and alveolar epithelial cells of the lungs and proximal and distal tubules of the kidneys. The presence of EIAV in the spleen and liver was expected due to viral tropism by macrophages, which are abundantly present in these organs. However, EIAV was also found in lung and kidney epithelial cells, indicating that the virus infects cell types other than macrophages. In conclusion, the immunohistochemical assay standardized in this study was able to detect EIAV antigens in spleen, liver, kidney and lung cells from naturally infected EIAV equids. Immunostaining observed in the spleen confirms viral tropism by mononuclear phagocytes; however, the presence of EIAV in lung and kidney epithelial cells indicates that virus may be eliminated in urine and/or oronasal secretions, suggesting new routes for viral excretion.

Wobbly syndrome in an Africa pygmy hedgehog (Atelerix albiventris): neuropathological and immunohistochemical studies / Síndrome de Wobbly em um ouriço pigmeu africano (Atelerix albiventris): estudo neuropatológico e imuno-histoquímico

ABSTRACT: A three-year-old female African pygmy hedgehog (Atelerix albiventris), born and domiciled in Brazil, presented apathy, prostration, and difficulty to stay standing. Its parents were siblings but did not present clinical signs related to this condition. As its clinical condition worsened, the animal was euthanized and referred for necropsy. No gross lesions were found in the central nervous system (CNS). Histologically, there was vacuolation with axonal degeneration in the white matter of the CNS and in peripheral nervous tissue. The Kluver-Barrera (KB) stain confirmed demyelination in vacuolated areas. Immunohistochemistry using several neural markers confirmed astrocytosis and microgliosis associated with vacuolated areas. In addition, there was a mild decrease in the immuno intensity of myelin proteolipid protein (PLP) in these areas. These results suggest a genetic origin of the present demyelination, which resulted in the wobbly syndrome described in this report.

RESUMO: Um ouriço pigmeu africano de três anos de idade, nascido e domiciliado no Brasil, apresentou apatia, prostração e dificuldade em permanecer em estação. Os pais deste ouriço eram irmãos, mas não apresentaram sinais clínicos relacionados a esta condição. Com a piora dos sinais clínicos, o animal foi eutanasiado e encaminhado para necropsia. Não foram encontradas lesões macroscópicas no sistema nervoso central (SNC). Histologicamente, havia vacuolização com degeneração axonal na substância branca do SNC e no tecido nervoso periférico. A coloração de Kluver-Barrera (KB) confirmou desmielinização nas áreas vacuolizadas e a imuno-histoquímica utilizando vários marcadores, confirmou astrocitose e microgliose associadas com as áreas de vacuolização. Além disso, houve discreta diminuição da imunointensidade da proteína proteolipídica da mielina (PLP) nessas áreas. Estes resultados sugerem origem genética da desmielinização que resultou na síndrome de wobbly descrita neste relato.

Splendore-Hoeppli phenomenon in a cat with osteomyelitis caused by Streptococcus species.

A 9-month-old male neutered mixed-breed cat had a history of chronic lameness of the right hind limb, which was non-responsive to antibiotic treatment. Hematologic analysis revealed marked neutrophilia and mild monocytosis. Radiography revealed extensive loss of cortical bone, and replacement with irregular and disorganized bone. There was loss of the normal cortico-medullary distinction, and the medullary cavity had an irregular radiodensity suggestive of osteomyelitis. Surgical curettage and antibiotics did not improve the clinical condition, and amputation was performed. Grossly, the skin over the right tibia was ulcerated with a viscous and granular exudate. At histopathology, there was marked diffuse pyogranulomatous dermatitis, myositis, periostitis and osteomyelitis associated with Splendore-Hoeppli phenomenon. In addition, there was marrow osteoproliferation and multifocal cortical loss, reabsorption, fibroplasia and endosteal bone formation. Gram staining revealed myriad slightly elongated Gram-positive bacteria, arranged in pairs or single chains, confirmed by polymerase chain reaction as Streptococcus species.