Cow-specific risk factors for clinical mastitis in Brazilian dairy cattle.

Information related to mastitis risk factors is useful for the design and implementation of clinical mastitis (CM) control programs. The first objective of our study was to model the risk of CM under Brazilian conditions, using cow-specific risk factors. Our second objective was to explore which risk factors were associated with the occurrence of the most common pathogens involved in Brazilian CM infections. The analyses were based on 65 months of data from 9,789 dairy cows and 12,464 CM cases. Cow-specific risk factors that could easily be measured in standard Brazilian dairy farms were used in the statistical analyses, which included logistic regression and multinomial logistic regression. The first month of lactation, high somatic cell count, rainy season and history of clinical mastitis cases were factors associated with CM for both primiparous and multiparous cows. In addition, parity and breed were also associated risk factors for multiparous cows. Of all CM cases, 54% showed positive bacteriological culturing results from which 57% were classified as environmental pathogens, with a large percentage of coliforms (35%). Coagulase-negative Staphylococcus (16%), Streptococcus uberis (9%), Streptococcus agalactiae (7%) and other Streptococci (9%) were also common pathogens. Among the pathogens analyzed, the association of cow-specific risk factors, such as Zebu breed (OR=5.84, 95%CI 3.77-10.77) and accumulated history of SCC (1.76, 95%CI 1.37-2.27), was different for CM caused by Coagulase-negative Staphylococcus and S. agalactiae in comparison to CM caused by coliforms. Our results suggest that CM control programs in Brazil should specially consider the recent history of clinical mastitis cases and the beginning of the lactations, mainly during the rainy season as important risk factor for mastitis.

Cathepsin D protects colorectal cancer cells from acetate-induced apoptosis through autophagy-independent degradation of damaged mitochondria.

Acetate is a short-chain fatty acid secreted by Propionibacteria from the human intestine, known to induce mitochondrial apoptotic death in colorectal cancer (CRC) cells. We previously established that acetate also induces lysosome membrane permeabilization in CRC cells, associated with release of the lysosomal protease cathepsin D (CatD), which has a well-established role in the mitochondrial apoptotic cascade. Unexpectedly, we showed that CatD has an antiapoptotic role in this process, as pepstatin A (a CatD inhibitor) increased acetate-induced apoptosis. These results mimicked our previous data in the yeast system showing that acetic acid activates a mitochondria-dependent apoptosis process associated with vacuolar membrane permeabilization and release of the vacuolar protease Pep4p, ortholog of mammalian CatD. Indeed, this protease was required for cell survival in a manner dependent on its catalytic activity and for efficient mitochondrial degradation independently of autophagy. In this study, we therefore assessed the role of CatD in acetate-induced mitochondrial alterations. We found that, similar to acetic acid in yeast, acetate-induced apoptosis is not associated with autophagy induction in CRC cells. Moreover, inhibition of CatD with small interfering RNA or pepstatin A enhanced apoptosis associated with higher mitochondrial dysfunction and increased mitochondrial mass. This effect seems to be specific, as inhibition of CatB and CatL with E-64d had no effect, nor were these proteases significantly released to the cytosol during acetate-induced apoptosis. Using yeast cells, we further show that the role of Pep4p in mitochondrial degradation depends on its protease activity and is complemented by CatD, indicating that this mechanism is conserved. In summary, the clues provided by the yeast model unveiled a novel CatD function in the degradation of damaged mitochondria when autophagy is impaired, which protects CRC cells from acetate-induced apoptosis. CatD inhibitors could therefore enhance acetate-mediated cancer cell death, presenting a novel strategy for prevention or therapy of CRC.

Yeast as a tool to explore cathepsin D function.

Cathepsin D has garnered increased attention in recent years, mainly since it has been associated with several human pathologies. In particular, cathepsin D is often overexpressed and hypersecreted in cancer cells, implying it may constitute a therapeutic target. However, cathepsin D can have both anti- and pro-survival functions depending on its proteolytic activity, cellular context and stress stimulus. Therefore, a more detailed understanding of cathepsin D regulation and how to modulate its apoptotic functions is clearly needed. In this review, we provide an overview of the role of cathepsin D in physiological and pathological scenarios. We then focus on the opposing functions of cathepsin D in apoptosis, particularly relevant in cancer research. Emphasis is given to the role of the yeast protease Pep4p, the vacuolar counterpart of cathepsin D, in life and death. Finally, we discuss how insights from yeast cathepsin D and its role in regulated cell death can unveil novel functions of mammalian cathepsin D in apoptosis and cancer.

Trânsito de suídeos em Minas Gerais, Brasil / Swine industry animal network in Minas Gerais, Brazil

Minas Gerais ocupa a quarta posição entre os estados brasileiros com maior produção de suídeos. A suinocultura envolve intenso trânsito de animal e, consequentemente, forma complexas redes de fluxo. Com a movimentação, esses animais podem carrear agentes patogênicos que podem ser disseminados por meio dessa rede de contatos. Diante disso, este estudo tem como objetivo descrever e analisar o trânsito de suídeos em Minas Gerais para compreender os caminhos mais prováveis para a disseminação de possíveis surtos. Os dados foram fornecidos pelo Instituto Mineiro de Agropecuária, originados das 56.823 Guias de Trânsito Animal emitidas no ano de 2009. A movimentação dos 5.354.735 suídeos foi analisada segundo a sua finalidade. O trânsito mais intenso ocorreu com a finalidade de abate (79,95%), seguida pelas finalidades de engorda (10,64%) e de reprodução (9,38%). A movimentação de animais para exposições e leilões representou apenas 0.03% dos transportes realizados. O trânsito em Minas Gerais é heterogêneo e concentra-se, principalmente, nas regiões do Triângulo Mineiro, Alto Paranaíba e Zona da Mata. As características do fluxo de animais tornam a utilização da estratégia das redes ideal para a elaboração das medidas de vigilância e controle das doenças dos suídeos em Minas Gerais.

Minas Gerais is the fourth largest Brazilian state in swine production. This activity involves the intense animal movement producing a complex network. In this context animals can carry on infectious agents and transmit them among the population. The aim of this study is to describe and analyze the movement of swine in Minas Gerais and to understand the most likely paths to spread possible outbreaks. Data were provided by the Instituto Mineiro de Agropecuária, derived from 56.823 Transit Animal Guides issued in 2009. The movement of 5.354.735 swine was analyzed according to its purpose. The traffic was more intense for slaughter (79.95%) followed by finishing (10.64%) and reproduction purposes (9.38%). The fairs and auction purposes represented only 0.03%. Movement of animals in Minas Gerais is heterogeneous and is mainly concentrated in same regions such as Alto Paranaíba and Zona da Mata. It also occurs in the Central and South regions. The network approach, based on graph theory, can be used more efficiently for the development of swine disease control programs and crisis management in Minas Gerais.

Acetate-induced apoptosis in colorectal carcinoma cells involves lysosomal membrane permeabilization and cathepsin D release.

Colorectal carcinoma (CRC) is one of the most common causes of cancer-related mortality. Short-chain fatty acids secreted by dietary propionibacteria from the intestine, such as acetate, induce apoptosis in CRC cells and may therefore be relevant in CRC prevention and therapy. We previously reported that acetic acid-induced apoptosis in Saccharomyces cerevisiae cells involves partial vacuole permeabilization and release of Pep4p, the yeast cathepsin D (CatD), which has a protective role in this process. In cancer cells, lysosomes have emerged as key players in apoptosis through selective lysosomal membrane permeabilization (LMP) and release of cathepsins. However, the role of CatD in CRC survival is controversial and has not been assessed in response to acetate. We aimed to ascertain whether LMP and CatD are involved in acetate-induced apoptosis in CRC cells. We showed that acetate per se inhibits proliferation and induces apoptosis. More importantly, we uncovered that acetate triggers LMP and CatD release to the cytosol. Pepstatin A (a CatD inhibitor) but not E64d (a cathepsin B and L inhibitor) increased acetate-induced apoptosis of CRC cells, suggesting that CatD has a protective role in this process. Our data indicate that acetate induces LMP and subsequent release of CatD in CRC cells undergoing apoptosis, and suggest exploiting novel strategies using acetate as a prevention/therapeutic agent in CRC, through simultaneous treatment with CatD inhibitors.

Distribuição espacial e temporal da raiva canina e felina em Minas Gerais, 2000 a 2006 / Spatial and temporal distribution of canine and feline rabies in Minas Gerais, Brazil, from 2000 to 2006

Estudou-se a epidemiologia da raiva em cães e gatos, em Minas Gerais, e realizou-se um estudo descritivo de seu comportamento, de 2000 a 2006. Utilizaram-se, como fonte de dados, os relatórios mensais dos laboratórios do Centro de Controle de Zoonoses de Belo Horizonte e do Instituto Mineiro de Agropecuária. Os resultados demonstraram positividade de 1,5 por cento para raiva canina e 0,7 por cento para raiva felina. Houve tendência ao decréscimo do número de casos positivos de raiva canina (y = -3,2143x + 19,714) e também para a raiva felina, com apenas dois casos, ambos em 2000. As regiões com diagnóstico positivo coincidiram com as de menor desenvolvimento sócioeconômico.

In order to know the epidemiology of rabies in dogs and cats, in Minas Gerais State, a descriptive study of its behavior was carried out from 2000 to 2006. Data of monthly reports colleted at the laboratories of "Centro de Controle de Zoonoses (CCZ)" from Belo Horizonte" and "Instituto Mineiro de Agropecuária (IMA)" were used. Positivity of 1.50 percent for canine rabies and 0.70 percent for feline rabies were observed. A tendency to the decrease of canine rabies positive cases was found (y= -3.2143x + 19.714) and the same was observed for cats, since only two cases occurred, both in 2000. The regions that present positive diagnostics also showed the lowest social economic development.

Distribuição espaço-temporal da raiva bovina em Minas Gerais, 1998 a 2006 / Space and time distribution of bovine rabies in Minas Gerais, 1998 to 2006

Estudou-se a situação epidemiológica da raiva bovina em Minas Gerais de 1998 a 2006. Foram avaliadas 6873 fichas de diagnóstico de raiva por imunofluorescência direta. Para análise da distribuição temporal da raiva, foram construídas tabelas e gráficos no software Excel 2003 e o mapeamento dos diagnósticos foi feito no aplicativo Tabwin 1.4. Verificou-se tendência anual decrescente do número de exames e dos diagnósticos positivos (Y= -41,133x+544,89). Os meses de maio, junho e julho apresentaram o maior percentual de diagnósticos positivos. O número de municípios com raiva bovina variou ao longo do período estudado e manteve tendência decrescente (Y= -7,0833x+166,64), com expansão da doença para os municípios da região do Triângulo Mineiro.

Epidemiological data of bovine rabies were evaluated after analyzing 6,873 files collected in Minas Gerais state, from 1998 to 2006. Direct Immunofluorescence was performed to diagnosis the disease. The temporal distribution of the disease was analyzed after tables and graphics were made using the software Excel 2003. A mapping diagnosis was built using the applicatory Tabwin 1.4. It was observed an annual decreasing tendency in the number positive diagnosis (Y= -41.133x+544.89). A higher percentage of positive diagnosis for rabies was observed from May to July. There was a variation in the number of counties in which bovine rabies was diagnosed during the studied period and it maintained a decreasing trend (Y= -7.0833x+166.64), with expansion of the disease in direction of "Triângulo Mineiro" counties.