2,509 research outputs found

    In vitro binding and survival assays of Leishmania parasites to peripherical blood monocytes and monocyte-derived macrophages isolated from dogs naturally and experimentally infected with Leishmania (Leishmania) chagasi

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    <p>Abstract</p> <p>Background</p> <p>There are a few works considering the characterization of canine monocyte-derived macrophages as well as a standardized procedure for isolation, culture, and infection of these cells with <it>Leishmania</it>. We have performed several modifications in order to improve the canine monocyte-derived macrophage cultures. In addition, we have done a comparative study between monocytes and monocyte-derived macrophages from dogs naturally and experimentally infected with <it>L. chagasi</it>.</p> <p>Results</p> <p>In the presence of exogenous serum, opsonized <it>Leishmania </it>promastigotes binds better to monocytes/macrophages than without serum. Otherwise, this binding occurs due to the strict correlation between the opsonized biologic particles with the third receptor of the complement (CR3-CD11b/CD18). In fact, our assays with CD11b confirmed the importance of this receptor for canine cells and the <it>L. chagasi </it>experimental system. Moreover, monocytes obtained from naturally infected dogs have shown a higher number of monocytes bounded to promastigotes. The experimental results regarding survival have shown that promastigote forms of opsonized <it>L. chagasi </it>were more infective, because we found higher numbers of promastigotes bound to the different cells. As a consequence, after forty-eight hours of binding, higher numbers of amastigotes appeared inside monocyte-macrophages.</p> <p>Conclusion</p> <p>These studies have given support to continue comparative studies involving canine monocytes, monocyte-derived macrophages and peritoneal macrophages. Since we have standardized the canine cell culture, we are looking forward to determining the phenotypic properties of these cells before and after <it>L. chagasi </it>infection using flow cytometry.</p

    Mechanisms of leukocyte lipid body formation and function in inflammation

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    An area of increasingly interest for the understanding of cell signaling are the spatio-temporal aspects of the different enzymes involved in lipid mediator generation (eicosanoid-forming enzymes, phospholipases and their regulatory kinases and phosphatases) and pools of lipid precursors. The compartmentalization of signaling components within discrete and dynamic sites in the cell is critical for specificity and efficiency of enzymatic reactions of phosphorilation, enzyme activation and function. We hypothesized that lipid bodies - inducible non-membrane bound cytoplasmic lipid domains - function as specialized intracellular sites of compartmentalization of signaling with major roles in lipid mediator formation within leukocytes engaged in inflammatory process. Over the past years substantial progresses have been made demonstrating that all enzymes involved in eicosanoid synthesis localize at lipid bodies and lipid bodies are distinct sites for eicosanoid generation. Here we will review our current knowledge on the mechanisms of formation and functions of lipid bodies pertinent to inflammation

    Feeding spectra and activity of the freshwater crab Trichodactylus kensleyi (Decapoda: Brachyura: Trichodactylidae) at La Plata basin

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    Background: In inland water systems, it is important to characterize the trophic links in order to identify the ‘trophic species’ and, from the studies of functional diversity, understand the dynamics of matter and energy in these environments. The aim of this study is to analyze the natural diet of Trichodactylus kensleyi of subtropical rainforest streams and corroborate the temporal variation in the trophic activity during day hours. Results: A total of 15 major taxonomic groups were recognized in gut contents. The index of relative importance identified the following main prey items in decreasing order of importance: vegetal remains, oligochaetes, chironomid larvae, and algae. A significant difference was found in the amount of full stomachs during day hours showing a less trophic activity at midday and afternoon. The index of relative importance values evidenced the consumption of different prey according to day moments. Results of the gut content indicate that T. kensleyi is an omnivorous crab like other trichodactylid species. Opportunistic behavior is revealed by the ingestion of organisms abundant in streams such as oligochaetes and chironomid larvae. The consumption of allochthonous plant debris shows the importance of this crab as shredder in subtropical streams. However, the effective assimilation of plant matter is yet unknown in trichodactylid crabs. Conclusions: This research provides knowledge that complements previous studies about trophic relationships of trichodactylid crabs and supported the importance of T. kensleyi in the transference of energy and matter from benthic community and riparian sources to superior trophic levels using both macro- and microfauna.Fil: Williner, VerĂłnica. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Santa Fe. Instituto Nacional de LimnologĂ­a. Universidad Nacional del Litoral. Instituto Nacional de LimnologĂ­a; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; ArgentinaFil: de Azevedo Carvalho, Debora. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Santa Fe. Instituto Nacional de LimnologĂ­a. Universidad Nacional del Litoral. Instituto Nacional de LimnologĂ­a; ArgentinaFil: Collins, Pablo Agustin. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Santa Fe. Instituto Nacional de LimnologĂ­a. Universidad Nacional del Litoral. Instituto Nacional de LimnologĂ­a; Argentina. Universidad Nacional del Litoral. Facultad de BioquĂ­mica y Ciencias BiolĂłgicas; Argentin

    Performance indicators for clinical practice management in primary care in Portugal : consensus from a Delphi study

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    Early OnlineBackground: Performance indicators assessing the quality of medical care and linked to pay for performance may cause disagreement. Portuguese indicators included in recent health care reform are controversial. Objectives: To obtain consensus from opinion leaders in family medicine regarding the performance indicators for practice management used in the evaluation of Family Health Units in Portugal. Methods: Eighty-nine specialists in primary care were invited to answer the following question in an online Delphi study: 'Which performance indicators should be assessed regarding the organization and management of clinical practice in primary care in Portugal?' A Likert scale was used to evaluate validity, reliability, feasibility and sensitivity to change. Twenty-seven experts participated in the second round and achieved a high degree of consensus. Eight categories were created for analysis. Results: The experts suggested the use of existing indicators as well as new indicators. Thirty-nine indicators suggested by the experts are currently in use in Portugal. The assessment of the number of clinical acts performed, the number of administrative acts, and evaluation of the clinical demographic profile achieved a high degree of consensus. The expert panel suggested fifty new indicators. Five categories of these new indicators had a high degree of consensus, and three categories had a low degree of consensus. Conclusion: The expert panel recommended that performance indicators of practice management should first assess the quantity of clinical and administrative activities undertaken. These indicators must take into account the human and financial resources available to the clinic and its demographic context

    Two-Fermion Bound States within the Bethe-Salpeter Approach

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    To solve the spinor-spinor Bethe-Salpeter equation in Euclidean space we propose a novel method related to the use of hyperspherical harmonics. We suggest an appropriate extension to form a new basis of spin-angular harmonics that is suitable for a representation of the vertex functions. We present a numerical algorithm to solve the Bethe-Salpeter equation and investigate in detail the properties of the solution for the scalar, pseudoscalar and vector meson exchange kernels including the stability of bound states. We also compare our results to the non relativistic ones and to the results given by light front dynamics.Comment: 32 pages, XIII Tables, 8 figure

    Performance assessment of the database downscaled ocean waves (DOW) on Santa Catarina coast, South Brazil

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    ABSTRACT: This work presents a validation of wave parameters from the new sixty years Downscaled Ocean Waves (DOW) reanalysis database. This study compares quantiles of the Gumbel distribution of Hs (significant wave height) and Tp (peak period) from simulated data with an 11 months' time series obtained from a buoy moored seaward on the Santa Catarina coast. Analysis by means of Gumbel distribution quantiles allows more weight to be given to the highest values of the time series, which are especially important in design projects. The statistical parameters used to verify the fit between the measured and the modeled data included: RMSE, BIAS, Scatter Index and Pearson Correlation Coefficient. Mean direction (9m) validation was conducted qualitatively. The database showed good fit of the mean conditions, especially Hs which was well Reproduced by the wave model. Underestimation of Tp, related mainly to the low spatial and temporal resolution of wind data used to generate waves, highlights this general modeling problem. Based on calculated statistical parameters, DOW data were considered comparable to the values obtained by measurements; however, such data must be cautiously used for extreme events analysis and in areas of bimodal sea conditions, where major deficiencies in the database were observed.The authors are also thankful to the Brazilian government through the MinistĂ©rio do Meio Ambiente (MMA) and the AgĂȘncia Brasileira de Cooperação (ABC) for the financial support of this research (within the project Transference of Methodologies and Tools to Support the Brazilian Coastal Management)
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