Influence of the Near-Cortical Over-Drilling Technique on the Mechanical Behaviour of Locking Plate Constructs Applied in Maned Wolf's Femur.

OBJECTIVE: The aim of this study was to evaluate the influence of near-cortical over-drilling holes on the mechanical behaviour of locking plate constructs applied in maned wolf's femur by using mechanical testing and finite element method (FEM). STUDY DESIGN: Seven pairs of adult maned wolves (Chrysocyon brachyurus) femur bones were randomly distributed into four groups. In all groups, a 3.5 mm locking compression plate, designed with 12 combi-holes and one locked, was applied to the lateral surface of the femur. G1 (n = 4) received bicortical locking screws placed in holes 1, 3, 5, 8, 10 and 12. In G2 (n = 5), the plate was applied as used in G1, but the application of the locked screws involved the near-cortical over-drilling technique. In G3 (n = 4), the plate was applied as used in G2, but the size of the near-cortical over-drilling was larger. The combi-holes 6 and 7 were maintained over a 10 mm fracture gap without screws. All constructs were tested for failure in the axial load. The axial load was applied eccentrically to the femoral head. RESULTS: Statistical differences were observed in the maximum load with G3 > G1 and G3 > G2, and in the deflection with G2 > G1 and G2 > G3. The FEM showed the lowest total displacement of the bone-plate constructs as well as of the plate in G1 compared with G2 and G3. CONCLUSION: The near-cortical over-drilling technique used in unstable fractures induced in the maned wolf's femur showed by static axial compression test that maximum load and deflection are dependent on drill hole size induced in the near-cortex. Based on FEM, the lowest total displacement of the bone-plate constructs was observed in Group 1.

Quantificação de subpopulações linfocitárias no sangue periférico de cães sadios adultos / Lymphocyte subsets in peripheral blood of adult healthy dogs

A citometria de fluxo vem se firmando como uma ferramenta útil na prática médico-veterinária, particularmente na clínica de pequenos animais. Tal conhecimento tem ensejado o estabelecimento de valores fisiológicos para diferentes subpopulações linfocitárias, indispensáveis à compreensão da dinâmica da celularidade linfóide, em diversas situações patológicas. Assim sendo, o presente ensaio teve como objetivo imunomarcar, por intermédio da técnica citométrica, as subpopulações linfocitárias CD5+CD4+, CD5+CD8+ e CD21+, em quatro diferentes raças de cães domésticos e sadios, de tal forma a agregar informações sobre o perfil imunológico das diferentes raças. Foram utilizados 40 cães adultos (2-7 anos), machos e fêmeas, das raças Beagle (G1, n=10), Golden Retriever (G2, n=10), Bulldog Inglês (G3, n=10) e sem raça definida (SRD) (G4, n=10). As colheitas de sangue foram realizadas por venipunção jugular, utilizando-se sistema de frascos a vácuo (K2-EDTA). O hemograma e o processamento das amostras para citometria de fluxo foram realizados num prazo máximo de 24 horas após a colheita do sangue. As amostras foram analisadas no citofluorômetro FACSCANTO (Becton Dickinson, San Jose, CA, USA). Utilizou-se o programa FACSDiva (Becton Dickinson, San Jose, CA, USA), para identificar e quantificar as células CD5+CD4+, CD5+CD8+ e CD21+, que forneceu o histograma e respectiva tabela com a quantidade de células detectadas pela imunofenotipagem. Os dados obtidos para contagem de linfócitos T auxiliares, T citotóxicos/supressores e linfócitos B foram tabulados e submetidos a Análise de Variância pelo teste F. O teste de Tukey a 5% de probabilidade foi utilizado para comparação das médias entre as diferentes raças de cães. Os valores médios de contagens de células CD5+CD8+ no sangue periférico do G1, G2, G3 e G4 foram de 155, 206, 544 e 503 células/µL, respectivamente. Os valores médios de contagens de células CD5+CD4+ no sangue periférico do G1, G2, G3 e G4 foram de 746, 642, 1101 e 855 células/µL, respectivamente. Os valores médios de contagens de células CD21+ no sangue periférico do G1, G2, G3 e G4 foram de 171, 299, 494 e 403 células/µL, respectivamente. Assim sendo, o número médio de células obtido para a subpopulação de linfócitos T citotóxicos foi significativamente maior (p<0,05) nos Bulldogs Ingleses e cães SRD, comparativamente aqueles encontrados nos grupos de Beagles e Golden Retrievers. Ademais, observou-se que o número médio de células obtido para a subpopulação de linfócitos B foi significavamente maior (p<0,05) nos Bulldogs Ingleses, quando comparado àquele dos Beagles.(AU)

Flow cytometry has established itself as a useful tool in veterinary practice, particularly for small animals practice. Such knowledge has made necessary the establishment of physiological values for different lymphocyte subpopulations, indispensable to understanding the dynamics of lymphoid cellularity in various pathological conditions. In this sense, the objective of this study was to determine, through cytometric technique, lymphocyte subsets of CD5+CD4+, CD5+CD8+ and CD21+ in four different breeds of domestic dogs, so to add information about the immunological profile of different breeds. A total of 40 adult dogs were used (2-7 years), being males and females of Beagles (G1, n=10), Golden Retrievers (G2, n=10), English Bulldogs (G3, n=10) and crossbreed dogs (G4, n=10). Blood samples were collected by jugular venipuncture, using vacuum flasks system (K2-EDTA). Hemogram and processing of samples for flow cytometry were performed within a maximum of 24 hours after blood collection. Samples were analyzed using FACSCanto device (Becton Dickinson, San Jose, CA, USA). FACSDiva software (Becton Dickinson, San Jose, CA, USA) was used to identify and quantify the CD5+ CD4+, CD5+CD8+, and CD21+, which provided the histogram and the respective table with the number of cells identified by immunophenotyping. The data obtained for T helper lymphocyte count, T cytotoxic/suppressor lymphocyte count and B lymphocytes were tabulated and submitted to analysis of variance by F test. Tukey test at 5% probability was used to compare means between the different breeds of dogs. The average values for CD5+CD8+ cell count in peripheral blood in G1, G2, G3 and G4 were of 155, 206, 544 and 503 cells/uL, respectively. The average values for CD5+CD4+ cell count in peripheral blood in G1, G2, G3 and G4 were of 746, 642, 855 and 1101 cells/uL, respectively. The average values for CD21 + cell count in peripheral blood for G1, G2, G3 and G4 were of 171, 299, 494 and 403 cells/uL, respectively. Therefore, The average number of cells obtained for the subsets of cytotoxic T lymphocytes was significantly higher (p<0,05) in the British Bulldogs and crossbreed dogs compared to those found in Beagles and Golden Retrievers. Furthermore, it was observed that the average number of cells obtained for the subsets of B lymphocytes was significantly higher (p<0,05) in English Bulldogs compared to that of Beagles.(AU)

Frequencies of virulence genes and pulse field gel electrophoresis fingerprints in Escherichia coli isolates from canine pyometra.

Escherichia coli is the most common bacterial agent isolated from canine pyometra. The frequencies of 24 virulence genes and pulsed field gel electrophoresis (PFGE) profiles were determined for 23 E. coli isolates from cases of canine pyometra in Brazil. The frequencies of virulence genes were 91.3% fimH, 91.3% irp-2, 82.6% fyuA, 56.5% iroN, 47.8% traT, 39.1% usp, 34.8% sfaD/E, 34.8% tsh, 30.4% papC, 30.4% hlyA, 26.1% papGIII, 26.1% cnf-1, 21.7% papE/F, 21.7% iss, 17.4% iutA, 17.4% ompT, 17.4% cvaC, 17.4% hlyF, 17.4% iucD, 13.0% iucC, 13.0% astA, 4.3% papGII, 0% afaB/C and 0% papGI. The high frequency of yersiniabactin (fyuA and irp2) and salmochelin (iroN) genes suggests that iron uptake systems might be important in the pathogenesis of canine pyometra. PFGE profiles of 19 isolates were heterogeneous, confirming that E. coli isolates from canine pyometra are unlikely to be epidemic clones.

Marginal activity of progesterone receptor B (PR-B) in dogs but high incidence of mammary cancer.

Progesterone plays an important role in the normal development and carcinogenesis of the mammary gland. In vitro studies have shown that the canine progesterone receptor B (cPR-B), which is essential for mammary development in the mouse, does not transactivate reporter constructs containing progesterone response elements. Therefore, the question was raised whether the cPR-B was completely devoid of transactivation potential of endogenous progesterone regulated genes. Canine mammary cell lines expressing doxycycline-inducible cPR-B, human PR-B or a chimera in which the canine B-upstream segment (BUS) was replaced by a human BUS were treated for 24h with doxycycline, progesterone or a combination of the two. The expression profiling was subsequently performed using a dog-specific microarray and miRNA primers. Incubation of stably transfected cell lines with doxycycline or progesterone alone, did not change expression of any endogenous gene. Expression of activated human PR-B or the chimera of human BUS with the canine PR resulted in differential expression of >500 genes whereas the activated cPR-B regulated only a subset of 40 genes and to a limited extent. The relevance of the marginal transactivation potential or the consequence of a lack of cPR-B function for the carcinogenesis of mammary gland tumors is discussed.