3,835 research outputs found

    Comparative study of osteogenic activity of multilayers made of synthetic and biogenic polyelectrolytes

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    Polyelectrolyte multilayer (PEM) coatings on biomaterials are applied to tailor adhesion, growth, and function of cells on biomedical implants. Here, biogenic and synthetic polyelectrolytes (PEL) are used for layer-by-layer assembly to study the osteogenic activity of PEM with human osteosarcoma MG-63 cells in a comparative manner. Formation of PEM is achieved with biogenic PEL fibrinogen (FBG) and poly-l-lysine (PLL) as well as biotinylated chondroitin sulfate (BCS) and avidin (AVI), while poly(allylamine hydrochloride) (PAH) and polystyrene sulfonate (PSS) represent a fully synthetic PEM used as a reference system here. Surface plasmon resonance measurements show highest layer mass for FBG/PLL and similar for PSS/PAH and BCS/AVI systems, while water contact angle and zeta potential measurements indicate larger differences for PSS/PAH and FBG/PLL but not for BCS/AVI multilayers. All PEM systems support cell adhesion and growth and promote osteogenic differentiation as well. However, FBG/PLL layers are superior regarding MG-63 cell adhesion during short-term culture, while the BCS/AVI system increases alkaline phosphatase activity in long-term culture. Particularly, a multilayer system based on affinity interaction like BCS/AVI may be useful for controlled presentation of biotinylated growth factors to promote growth and differentiation of cells for biomedical applications

    Actividad antioxidante de las flores de Taraxacum officinale L. \"diente de león\" procedente de Otuzco

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    En este trabajo, nuestro objetivo fue determinar la capacidad antioxidante del extracto etan√≥lico de p√©talos de diente de Le√≥n (Taraxacum officinale L.). Las muestras estudiadas fueron colectadas en el municipio de Otuzco, regi√≥n La Libertad, provincia de Otuzco. El esp√©cimen vegetal fue identificado y clasificado en el Herbarium truxillense (HUT). Solo se cosecharon las plantas con flores en buen estado para obtener los p√©talos y se secaron en una estufa a 40 ¬įC. Luego se obtuvieron los extractos por reflujo con etanol de 70¬į GL como menstruo. Se us√≥ el m√©todo DPPH desarrollado por Blois en el a√Īo 1958 para determinar la capacidad antioxidante y se obtuvo un IC50 de 1.34 para el extracto hidroalcoh√≥lico de p√©talos de diente de le√≥n; y un IC50 de 1.14 para el √°cido asc√≥rbico (sustancia de referencia), lo cual confirma que la capacidad antioxidante del extracto en investigaci√≥n fue inferior a la del √°cido asc√≥rbico. Este hecho se confirma al comparar los valores de la capacidad antioxidante relativa (AAR), donde el valor determinado para el extracto fue de 117,54%, considerando como 100% el valor de AAR para el √°cido asc√≥rbico.Tesi

    Engineered microenvironments for synergistic VEGF - integrin signalling during vascularization

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    We have engineered polymer-based microenvironments that promote vasculogenesis both in vitro and in vivo through synergistic integrin-growth factor receptor signalling. Poly(ethyl acrylate) (PEA) triggers spontaneous organization of fibronectin (FN) into nanonetworks which provide availability of critical binding domains. Importantly, the growth factor binding (FNIII12-14) and integrin binding (FNIII9-10) regions are simultaneously available on FN fibrils assembled on PEA. This material platform promotes synergistic integrin/VEGF signalling which is highly effective for vascularization events in vitro with low concentrations of VEGF. VEGF specifically binds to FN fibrils on PEA compared to control polymers (poly(methyl acrylate), PMA) where FN remains in a globular conformation and integrin/GF binding domains are not simultaneously available. The vasculogenic response of human endothelial cells seeded on these synergistic interfaces (VEGF bound to FN assembled on PEA) was significantly improved compared to soluble administration of VEGF at higher doses. Early onset of VEGF signalling (PLCő≥1 phosphorylation) and both integrin and VEGF signalling (ERK1/2 phosphorylation) were increased only when VEGF was bound to FN nanonetworks on PEA, while soluble VEGF did not influence early signalling. Experiments with mutant FN molecules with impaired integrin binding site (FN-RGE) confirmed the role of the integrin binding site of FN on the vasculogenic response via combined integrin/VEGF signalling. In vivo experiments using 3D scaffolds coated with FN and VEGF implanted in the murine fat pad demonstrated pro-vascularization signalling by enhanced formation of new tissue inside scaffold pores. PEA-driven organization of FN promotes efficient presentation of VEGF to promote vascularization in regenerative medicine applications

    QUANDO O PROVIS√ďRIO SE TORNA PERMANENTE: A OPERA√á√ÉO ACOLHIDA COMO POL√ćTICA MIGRAT√ďRIA NO BRASIL

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    O Brasil √© o quinto pa√≠s receptor do fluxo de venezuelanos na regi√£o e o segundo com mais venezuelanos refugiados. √Ä medida que essa situa√ß√£o ganhou √≠mpeto, os governos municipal e estadual se viram despreparados para responder √†s necessidades b√°sicas decorrentes do aumento do fluxo de refugiados e imigrantes venezuelanos. Em 2018, na tentativa de administrar o fluxo venezuelano, o Estado brasileiro implementou a Opera√ß√£o Acolhida, uma for√ßa-tarefa militar-humanit√°ria para controle, acolhimento e integra√ß√£o dos imigrantes que entravam pela fronteira norte no estado de Roraima. Com base na premissa de que a pol√≠tica p√ļblica n√£o √© uma a√ß√£o governamental programada para responder a uma demanda pontual, mas, que contempla a√ß√Ķes intencionais que fazem uso de instrumentos e recursos para oferecer ‚Äúsolu√ß√Ķes duradouras‚ÄĚ e alcan√ßar benef√≠cios p√ļblicos, este artigo analisou a ‚ÄúOpera√ß√£o Acolhida‚ÄĚ como uma pol√≠tica p√ļblica de car√°ter migrat√≥rio a partir da perspectiva de ciclo pol√≠tico. Dentre as conclus√Ķes, pode-se citar a fragilidade do sistema e das pol√≠ticas de acolhimento e assist√™ncia aos imigrantes no √Ęmbito municipal, especialmente em rela√ß√£o ao or√ßamento e financiamento. Ainda a inten√ß√£o do governo brasileiro em resolver a quest√£o do fluxo migrat√≥rio venezuelano de maneira provis√≥ria, sem a necessidade de trazer ao debate p√ļblico o que rege o artigo 120 da Lei de Migra√ß√Ķes: cria√ß√£o de uma ‚ÄúPol√≠tica Nacional de Migra√ß√Ķes, Ref√ļgio e Apatridia‚ÄĚ

    The role of heart rate on the associations between body composition and heart rate variability in children with overweight/obesity : the ActiveBrains project

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    Background: Heart rate variability (HRV) is negatively associated with body mass index and adiposity in several populations. However, less information is available about this association in children with overweight and obesity, especially severe/morbid obesity, taking into consideration the dependence of HRV on heart rate (HR). Objectives: (1) to examine associations between body composition measures and HRV, (2) to study differences in HRV between children with overweight and severe/morbid obesity; and (3) to test whether relationships and differences tested in objectives 1 and 2, respectively are explained by the dependency of HRV on HR. Methods: A total of 107 children with overweight/obesity (58% boys, 10.03 +/- 1.13 years) participated in this study. Body composition measures were evaluated by Dual-energy X-ray absorptiometry (DXA). HRV parameters were measured with Polar RS800CXR (R). Results: Body composition measures were negatively associated with HRV indicators of parasympathetic activity (beta values ranging from -0.207 to -0.307, all p 0.05). Conclusion: All associations between adiposity/obesity and HRV could be explained by HR, suggesting a key confounding role of HR in HRV studies in children with weight disturbances

    Capturing the Severity and Impairment Associated With Depression: The Overall Depression Severity and Impairment Scale (ODSIS) Validation in a Spanish Clinical Sample

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    Background: The Overall Depression Severity and Impairment Scale (ODSIS) is a self-report scale designed to evaluate the severity and functional impairment associated with depression. Objective: This study evaluated the psychometric properties of the online version of the ODSIS in Spanish outpatients with depression and anxiety disorders. Method: Patients with a main diagnosis of a depressive (n = 283) or anxiety disorder (n = 191) and a mean age of 38.15 (SD = 12.06) were evaluated with a clinical diagnostic interview and measures assessing depression, anxiety, positive and negative affect, and quality of life. Factorial structure, internal consistency, convergent, and discriminant validity and cutoff scores were analyzed. Results: Consistent with previous validations of the instrument, Confirmatory Factor Analysis showed a unidimensional factor structure. Furthermore, the results obtained supported the internal consistency and construct validity of the ODSIS scores. A score of 5 was found to meet the criteria used in this study for the optimal cutoff score. Conclusion: The results obtained in this study show that the Spanish version of the ODSIS delivered online is an adequate tool to assess the depression-related severity and impairment in a brief and easy fashion
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