Canine cavitary effusion: a retrospective study of 304 cases in Brazil

ABSTRACT The objective of this study was to determine the frequency of different categories of specific and general classification in canine cavitary effusions (CE), as well as their association with the underlying etiologies. The laboratorial and clinical data from 304 cases of canine CE were retrospectively assessed. In 32.9% (100 cases), at least one of the specific classification categories was established, with a subtotal predominance of neoplasia (42%), bacterial serositis (24%) and hemorrhage (16%). Neoplasia was confirmed by effusion cytology in 57.5% of the cases with histopathological confirmation. From the cases in which the specific classification was not obtained, 35.8% were classified as modified transudate, 30.4% as pure transudate, 21.1% % as exudate and 12.7% was not included in any general category. The most common causes of effusion among these cases were hypoproteinemia and/or hipoalbuminemia (HPHA) (25.8%), hepatopathy (22.5%), cardiac insufficiency (15.5%) and cytologically undetected cases of neoplasia (12.4%). In conclusion, HPHA, hepatopathy and neoplasia represents important etiologies for canine CE development. Classification of effusions, solely based on [TP] and TNCC, might be an inaccurate diagnostic tool of effusions. New laboratorial classification methods for canine CE should be researched.

Platelets Inhibit Migration of Canine Osteosarcoma Cells

The interaction between platelets and tumour cells is important for tumour growth and metastasis. Thrombocytopenia or antiplatelet treatment negatively impact on cancer metastasis, demonstrating potentially important roles for platelets in tumour progression. To our knowledge, there is no information regarding the role of platelets in cancer progression in dogs. This study was designed to test whether canine platelets affected the migratory behaviour of three canine osteosarcoma cell lines and to give insights of molecular mechanisms. Intact platelets, platelet lysate and platelet releasate inhibited the migration of canine osteosarcoma cell lines. Addition of blood leucocytes to the platelet samples did not alter the inhibitory effect on migration. Platelet treatment also significantly downregulated the transcriptional levels of SNAI2 and TWIST1 genes. The interaction between canine platelets or molecules released during platelet activation and these tumour cell lines inhibits their migration, which suggests that canine platelets might antagonize metastasis of canine osteosarcoma. This effect is probably due to, at least in part, downregulation of genes related to epithelial-mesenchymal transition.

Analytical validation of a quantitative reverse transcriptase polymerase chain reaction assay for evaluation of T-cell targeted immunosuppressive therapy in the dog

Cyclosporine is an immunosuppressive agent that inhibits T-cell function by decreasing production of cytokines such as interleukin-2 (IL-2) and interferon-γ(IFN-γ). In dogs, there is currently no reliable analytical method for determining effective cyclosporine dosages in individual patients. Our laboratory has developed a quantitative reverse transcriptase polymerase chain reaction (RT-qPCR) assay that measures IL-2 and IFN-γ gene expression, with the goal of quantifying immunosuppression in dogs treated with cyclosporine. This study focuses on analytical validation of our assay, and on the effects of sample storage conditions on cyclosporine-exposed samples. Heparinized whole blood collected from healthy adult dogs was exposed to a typical post-treatment blood concentration for cyclosporine(500 ng/mL) for 1 h, and then stored for 0, 24, and 48 h at both room temperature and 4 ◦C.The study was then repeated using a cyclosporine concentration of 75 ng/mL, with sample storage for 0, 24, and 48 h at 4 ◦C. Cytokine gene expression was measured using RT-qPCR,and assay efficiency and inter- and intra-assay variability were determined. Storage for upto 24 h at room temperature, and up to 48 h at 4 ◦C, did not significantly alter results compared to samples that were processed immediately. Validation studies showed our assay to be highly efficient and reproducible and robust enough to be feasible under standard practice submission conditions.

Pharmacokinetic evaluation of oral dantrolene in the dog

The pharmacokinetics of dantrolene and its active metabolite, 5-hydroxydantrolene, after a single oral dose of either 5 or 10 mg/kg of dantrolene was determined. The effects of exposure to dantrolene and 5-hydroxydantrolene on activated whole-blood gene expression of the cytokines interleukin-2 (IL-2) and interferon-γ (IFN-γ) were also investigated. When dantrolene was administered at a 5 mg/kg dose, peak plasma concentration (Cmax ) was 0.43 μg/mL, terminal half-life (t1/2 ) was 1.26 h, and area under the time-concentration curve (AUC) was 3.87 μg·h/mL. For the 10 mg/kg dose, Cmax was 0.65 μg/mL, t1/2 was 1.21 h, and AUC was 5.94 μg·h/mL. For all calculated parameters, however, there were large standard deviations and wide ranges noted between and within individual dogs: t1/2 , for example, ranged from 0.43 to 6.93 h, Cmax ratios ranged from 1.05 to 3.39, and relative bioavailability (rF) values ranged from 0.02 to 1.56. While activated whole-blood expression of IL-2 and IFN-γ as measured by qRT-PCR was markedly suppressed following exposure to very high concentrations (30 and 50 μg/mL, respectively) of both dantrolene and 5-hydroxydantrolene, biologically and therapeutically relevant suppression of cytokine expression did not occur at the much lower drug concentrations achieved with oral dantrolene dosing.

Evidence of selective packaging and different α-granule subtypes in canine platelets

Platelets are circulating megakaryocytic cytoplasmic fragments that are required to maintain vascular integrity and prevent haemorrhage. During activation, platelets release hundreds of bioactive proteins, mainly by secretion of α-granule content. These proteins include von Willebrand factor (vWF) and fibrinogen, major adhesive proteins involved in haemostasis. Human and mouse platelet α-granules are packaged selectively to contain different molecules and platelets can differentially release these proteins on specific receptor activation. Confocal laser scanning microscopy was used to analyse vWF and fibrinogen localization within canine platelet α-granules. In resting canine platelets, the majority of platelet vWF and fibrinogen is located in separate α-granule populations. These findings provide evidence that canine platelets contain different α-granule subtypes, suggesting that selective protein packaging occurs during canine platelet ontology.

Atividade funcional neutrofílica em cabras com mastite induzida experimentalmente por Staphylococcus aureus e suplementadas com vitamina E (acetato DL-a-tocoferol)

Avaliou-se a função neutrofílica em cabras com mastite por Staphylococcus aureus, induzida experimentalmente, suplementadas com vitamina E (acetato DL-a-tocoferol). Foram utilizadas 14 cabras gestantes da raça Saanen, com idades entre 8 e 12 meses e com cultura bacteriológica do leite negativa. Sete cabras receberam 2000UI de vitamina E, via intramuscular, no dia do parto e no sétimo dia pós-parto. As outras sete não foram medicadas. No 10º dia pós-parto, os dois grupos foram inoculados com 300 unidades formadoras de colônias de Staphylococcus aureus, cepa ATCC 25923, diluídas em 10ml de solução fisiológica, na glândula mamária esquerda. A função de neutrófilos sangüíneos foi medida pelo teste nitroazul tetrazólio (NBT), antes da inoculação, no momento da infecção e 12, 24, 48 e 72 horas pós-infecção, quando foi instituído o tratamento intramamário com antimicrobiano, por três dias consecutivos. A colheita final de sangue foi realizada 48 horas após a última aplicação do medicamento. Amostras de sangue para determinação da vitamina E foram colhidas no dia do parto, no momento da infecção, 48 horas pós-infecção e 48 horas pós-tratamento e analisadas por cromatografia líquida de alta performance. Na prova não estimulada do NBT não foram verificadas diferenças entre grupos e entre momentos. Na prova estimulada do NBT (NBT-E) houve diferença entre tratamentos às 12 e 72 horas pós-infecção, com valores mais elevados de NBT-E nos animais sem suplementação. Conclui-se que a suplementação com vitamina E reduz o percentual de neutrófilos NBT-E positivos.