7,809 research outputs found

    Angiogênese, homeostasia e câncer: novos paradigmas e velhos problemas

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    Neovascularization is a crucial phenomenon for the continuous growing of neoplastic cells and cancer progression. The growth of new blood vessels from pre-existing vessels (angiogenesis) occurs in several physiological and pathological conditions, including cancer, where it is critical for tumor-cells nutrition. Recently, new remarkable insights regarding angiogenesis and blood coagulation (key events in vascular biology) have been described. The serine protease thrombin, which plays a central role in blood coagulation cascade through its ability to cleave fibrinogen conducting to fibrin clot formation, is also known to be involved in embryogenesis, inflammation, wound healing, through its active role on vascular remodeling. Although the increased knowledge of factors regulating angiogenesis and coagulation led to the understanding that angiogenesis, homeostasis and carcinogenesis are three close team players, little is still known about how these pathways support each other in the process of angiogenesis in vivo. This review summarizes current understanding of blood coagulation cascade role in conducting angiogenesis and tumor progression, as well as provides an overview of the emerging anti-angiogenic and anti-coagulation therapies inducing tumor regression.A neovascularização é um processo fundamental para a sobrevivência e a progressão das células neoplásicas malignas. O crescimento de novos vasos sanguíneos a partir de vasos já existentes, fenômeno designado como angiogênese, está envolvido em vários processos fisiológicos e patológicos, incluindo o crescimento tumoral, onde a angiogênese desempenha papel crítico na nutrição das células tumorais. Tal como a angiogênese, o sistema de coagulação sanguínea exerce importante função na biologia vascular. A trombina, uma serina protease, tem papel fundamental na cascata de coagulação, pela quebra enzimática do fibrinogênio e pela conseqüente produção de fibrina. Essa protease encontra-se também implicada em desenvolvimento embrionário, inflamação e cicatrização, processos nos quais a remodelação vascular está altamente ativa. Apesar de o crescente conhecimento de fatores reguladores da angiogênese e da coagulação demonstrar que a carcinogênese, a coagulação e a angiogênese são três close team players, ainda muito pouco se sabe sobre o modo como esses players comunicam-se e interagem no processo de angiogênese in vivo. Esta revisão sumariza os conhecimentos atuais quanto ao papel da cascata de coagulação na condução do processo angiogênico e do crescimento tumoral, bem como oferece uma visão geral sobre recentes terapias antiangiogênicas e anticoagulantes envolvidas na regressão tumoral.(undefined

    Lymphangiogenesis: from the pig embryos to cancer

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    The discovery and the comprehension of lymphatic vessels suffered several historical delays and setbacks. The inherent anatomical problems slowed down the precise identification of the lymphatic system during the development of medical science. Gasparo Aselli, an Italian surgeon and anatomist, was the first to describe the lymphatic vessels in 1627 (De Lacteibus sive Lacteis Venis). However, most original descriptions that report the morphology of the lymphatic system in different organisms were done during the 19th and the 20th centuries. The recent identification of specific lymphatic vasculature molecular markers allows a more accurate identification and characterization of the lymphatic system evolution in different organs, as well as its role in different pathological conditions, including cancer. This study summarizes the current understanding of lymphangiogenesis in tumour progression, as well as it presents a review of the promising data regarding the prognostic value of lymphatic density and the use of therapeutic lymphangiogenic molecules.A descoberta dos vasos linfáticos e sua compreensão enfrentaram uma série de atrasos e dificuldades históricos. As inerentes dificuldades anatômicas retardaram a identificação precisa da rede vascular linfática durante o desenvolvimento da ciência médica. Gasparo Aselli, um anatomista e cirurgião italiano, foi o primeiro a descrever os vasos linfáticos, em 1627 (De Lacteibus sive Lacteis Venis). Entretanto, a maioria das descrições originais que relatam a morfologia do sistema linfático nos diferentes organismos foi realizada depois, entre os séculos XIX e XX. A recente identificação de marcadores moleculares específicos à vasculatura linfática permite agora identificação e caracterização mais acuradas da evolução da rede linfática nos vários órgãos e em diferentes situações, inclusive no câncer. Esta revisão resume o conhecimento sobre a linfangiogênese na progressão tumoral, bem como apresenta uma síntese dos dados mais promissores em relação ao valor prognóstico da densidade linfática e da utilização das moléculas linfangiogênicas como alvo terapêutico.(undefined

    Atmospheric Deposition on Swiss Long-Term Forest Ecosystem Research (LWF) Plots

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    Atmospheric deposition of the major elements was estimated from throughfall and bulk deposition measurements on 13 plots of the Swiss Long-Term Forest Ecosystem Research (LWF) between 1995 and 2001. Independent estimates of the wet and dry deposition of nitrogen (N) and sulfur (S) on these same plots were gained from combined simplified models. The highest deposition fluxes were measured at Novaggio (Southern Switzerland), exposed to heavy air pollution originating from the Po Plain, with throughfall fluxes averaging 29 kg ha−1 a−1 for N and 15 kg ha−1 a−1 for S. Low deposition fluxes were measured on the plots above 1800 m, with throughfall fluxes lower than 4.5 kg ha−1 a−1 for N and lower than 3 kg ha−1 a−1 for S. The wet deposition of N and S derived from bulk deposition was close to the modeled wet deposition, but the dry deposition derived from throughfall was significantly lower than the modeled dry deposition for both compounds. However, both the throughfall method and the model yielded total deposition estimates of N which exceeded the critical loads calculated on the basis of long-term mass balance considerations. These estimates were within or above the range of empirical critical loads except above 1800

    Alkaloids from the Sponge Stylissa carteri Present Prospective Scaffolds for the Inhibition of Human Immunodeficiency Virus 1 (HIV-1).

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    The sponge Stylissa carteri is known to produce a number of secondary metabolites displaying anti-fouling, anti-inflammatory, and anti-cancer activity. However, the anti-viral potential of metabolites produced by S. carteri has not been extensively explored. In this study, an S. carteri extract was HPLC fractionated and a cell based assay was used to evaluate the effects of HPLC fractions on parameters of Human Immunodeficiency Virus (HIV-1) infection and cell viability. Candidate HIV-1 inhibitory fractions were then analyzed for the presence of potential HIV-1 inhibitory compounds by mass spectrometry, leading to the identification of three previously characterized compounds, i.e., debromohymenialdisine (DBH), hymenialdisine (HD), and oroidin. Commercially available purified versions of these molecules were re-tested to assess their antiviral potential in greater detail. Specifically, DBH and HD exhibit a 30%-40% inhibition of HIV-1 at 3.1 μM and 13 μM, respectively; however, both exhibited cytotoxicity. Conversely, oroidin displayed a 50% inhibition of viral replication at 50 μM with no associated toxicity. Additional experimentation using a biochemical assay revealed that oroidin inhibited the activity of the HIV-1 Reverse Transcriptase up to 90% at 25 μM. Taken together, the chemical search space was narrowed and previously isolated compounds with an unexplored anti-viral potential were found. Our results support exploration of marine natural products for anti-viral drug discovery

    Gestão Empreendedora: Perfil e Trajetória das Mulheres Gestoras de Uma Instituição de Ensino Superior

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    A nova tônica que vem permeando os estudos de empreendedorismo volta-se para o empreendedorismo feminino. As mulheres têm adquirido posições de destaque na economia e nos negócios e detém, atualmente, uma fatia importante dos empreendimentos em muitos países. Este fato estimula a realização de pesquisas sobre diferentes aspectos, nesta temática. Assim, se estudaram as mulheres gestoras em uma Instituição de Ensino Superior (IES) da região do Vale do Itajaí, em Santa Catarina, Brasil. A pesquisa foi exploratória, com método qualitativo, realizada por meio de entrevista, com um roteiro básico, sendo respondida por 46 gestoras desta IES. Os resultados mostram que estas gestoras caracterizam-se, em sua maioria, como mulheres com mais de 40 anos, tituladas como mestres e/ou doutoras, tendo até dez anos de trabalho na instituição estudada. As gestoras consideram necessário para ser uma empreendedora de sucesso na Instituição de Ensino Superior, principalmente, a educação continuada e a busca de informação e de conhecimento

    Efeito De Técnicas De Polimento Na Estabilidade Da Cor E Rugosidade Superficial De Resinas Compostas Microhibridas

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    Resin roughness and staining is a common problem in dentistry. Objective: the aim of this study was to verify the influence of single and multiple-steps polishing techniques on color stability and surface roughness of differents composite resins. Groups were (n=10): FS+CS. Filtek Supreme XT + clear strip; FS+PG. Filtek Supreme XT+PoGo; FS+SF. Filtek Supreme XT+Sof-Lex; AM+CS. Amelogen+clear strip; AM+PG. Amelogen+PoGo; AM+SF. Amelogen+Sof-Lex; TEC+CL. TetricEvoCeram + clear strip; TEC+PG. Tetric EvoCeram+PoGo; TEC+SF. Tetric EvoCeram+Sof-Lex; CED+CS. Ceram X Duo+clear strip; CED+PG. Ceram X Duo+PoGo; CED+SF. Ceram X Duo+ Sof-Lex. The initial color and roughness were determined before and after the polishing procedures. All specimens were stored for 7 days in coffee solution and the color assessment was performed. Two specimens from each group were evaluated by scanning electron microscopy. Roughness and color data were submitted to ANOVA and Tukey tests(pG7(5.8f)=G10(5.7ef)>G1(3.7c), followed by the G6(5.9f)>G9(3.1bc)=G12(2.1ab)>G3(1.7a). G3, after 7 days, presented the lowest values for Delta E(1.704). The lowest roughness values were observed when the clear strips were used regardless material type. The Sof-Lex system provided the lowest surface roughness values for all tested composite resins. Among composite resins the highest roughness values were found for Amelogen (G5-0.49 and G6-0.35), regardless polishing technique. All tested materials presented changes in color after immersion in coffee solution. The roughness surface and the staining of composite resins are material and polishing technique dependents.32126227

    Illuminating Smart City Solutions – A Taxonomy and Clusters

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    With urban problems intensifying, Smart City solutions are recognized by researchers and practitioners as one of the most promising solutions to make urban areas economically, environmentally, and socially sustainable. While many elements of Smart City solutions have been explored, existing works either treat Smart City solutions as technical black boxes or focus exclusively on Smart City solutions’ technical or non-technical characteristics. Therefore, to conceptualize the unique characteristics of Smart City solutions currently available, we developed a multi-layer taxonomy based on Smart City solution literature and a sample of 106 Smart City solutions. Moreover, we identified three clusters, each covering a typical combination of characteristics of Smart City solutions. We evaluated our findings by applying the Q-sort method. The results contribute to the descriptive knowledge of Smart City solutions as a first step for a theory for analyzing and enable researchers and practitioners to understand Smart City solutions more holistically

    A decade of monitoring at Swiss Long-Term Forest Ecosystem Research (LWF) sites: can we observe trends in atmospheric acid deposition and in soil solution acidity?

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    Trends in atmospheric acid deposition and in soil solution acidity from 1995 or later until 2007 were investigated at several forest sites throughout Switzerland to assess the effects of air pollution abatements on deposition and the response of the soil solution chemistry. Deposition of the major elements was estimated from throughfall and bulk deposition measurements at nine sites of the Swiss Long-Term Forest Ecosystem Research network (LWF) since 1995 or later. Soil solution was measured at seven plots at four soil depths since 1998 or later. Trends in the molar ratio of base cations to aluminum (BC/Al) in soil solutions and in concentrations and fluxes of inorganic N (NO3-N + NH4-N), sulfate (SO4-S), and base cations (BC) were used to detect changes in soil solution chemistry. Acid deposition significantly decreased at three out of the nine study sites due to a decrease in total N deposition. Total SO4-S deposition decreased at the nine sites, but due to the relatively low amount of SO4-S load compared to N deposition, it did not contribute to decrease acid deposition significantly. No trend in total BC deposition was detected. In the soil solution, no trend in concentrations and fluxes of BC, SO4-S, and inorganic N were found at most soil depths at five out of the seven sites. This suggests that the soil solution reacted very little to the changes in atmospheric deposition. A stronger reduction in base cations compared to aluminum was detected at two sites, which might indicate that acidification of the soil solution was proceeding faster at these site
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