82 research outputs found

    Functionalized CoCr surfaces with adhesive molecules to improve endothelialization

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    Versi贸 amb diverses seccions encriptades, per drets a'autorCobalt-chromium (CoCr) alloys are widely used as biomaterials for coronary stents due to their excellent mechanical properties, biocompatibility and corrosion resistance. However, these materials are bioinert, retarding the complete endothelialization and resulting in a higher risk of restenosis, narrowing of the artery, and late-stent thrombosis. Therefore, the improvement of implants surface endothelialization has acquired importance in the last years. Immobilization of cell adhesive biomolecules onto biomaterials surface is a well-known strategy to control cell response. However, the strategy of immobilization, the optimal combination or the appropriate spatial presentation of the bioactive sequences to enhance endothelialization for cardiovascular applications, remains to be elucidated. The present PhD thesis focused on the development of a new biofunctionalized CoCr alloy surfaces in order to improve the endothelialization. To that end, elastin-like recombinamers (ELR) genetically modified with an REDV (Arg-Glu-Asp-Val) sequence and short synthetized peptides RGDS (Arg-Gly-Asp-Ser), REDV, YIGSR (Tyr-Ile-Gly-Ser-Arg) and their equimolar combination, were attached by physisorption and covalent bonding onto CoCr alloy surfaces and thoroughly characterized physico-chemically and evaluated in vitro with human umbilical vein endothelial cells (HUVECs), coronary artery smooth muscle cells (CASMCs) and platelets from blood donors. First, biofunctionalized surfaces with ELR were developed and optimized by evaluating different surface activation treatments, oxygen plasma and sodium hydroxide etching, and different binding strategies, physisorption and covalent bonding. The functionalized surfaces demonstrated a higher cell adhesion and spreading of HUVEC cells, this effect is emphasized as increases the amount of immobilized biomolecules and directly related to the immobilization technique: covalent bonding. Nevertheless, the silanization process was not completely effective since a mixture of covalent and physisorption behavior was observed probably due to the use of big molecules that decreased the control of the bonding between the biomolecule and the surface. Secondly, it was synthetized immobilized RGDS, REDV, YIGSR and their equimolar combination peptides onto the different surfaces. Cell studies demonstrated that the covalent functionalization of CoCr surfaces with an equimolar combination of RGDS/YIGSR represented the most powerful strategy to enhance the early stages of HUVECs adhesion, proliferation and migration, indicating a positive synergistic effect between the two peptide motifs. Besides, gene expression and platelet adhesion studies showed that surfaces silanized with the combination RGDS/YIGSR improved anti-thrombogenicity compared to non-modified surfaces. Finally, cell co-cultures of HUVECs/CASMCs found that functionalization increased the amount of adhered HUVECs onto modified surfaces compared to plain CoCr, independently of the used peptide and the strategy of immobilization. Overall, the present thesis offer a comprehensive view of the effectiveness of immobilizing cell adhesive molecules onto CoCr alloy surfaces to enhance endothelialization while preventing restenosis and thrombosis for cardiovascular applications.Las aleaciones de cobalto-cromo (CoCr) son ampliamente utilizadas como biomateriales para stents coronarios debido a sus excelentes propiedades mec谩nicas, biocompatibilidad y resistencia a la corrosi贸n. Sin embargo, estos materiales son bio-inertales, retardando la completa endotelializaci贸n y resultando en un mayor riesgo de reestenosis, estrechamiento de la arteria y trombosis tard铆a. Por lo tanto, la mejora de la endotelizaci贸n de superficie de los implantes ha adquirido importancia en los 煤ltimos a帽os. La inmovilizaci贸n de biomol茅culas adhesivas celulares sobre la superficie de los biomateriales es una estrategia bien conocida para controlar la respuesta celular. Sin embargo, queda por aclararse la estrategia de inmovilizaci贸n, la combinaci贸n 贸ptima o la presentaci贸n espacial apropiada de las secuencias bioactivas para potenciar la endotelizaci贸n en aplicaciones cardiovasculares. La presente tesis doctoral se centr贸 en el desarrollo de una nueva superficie biofuncionalizada de la aleaci贸n CoCr con el fin de mejorar la endotelializaci贸n. Para ello, los recombinameros tipo elastina (ELR) modificados gen茅ticamente con una secuencia REDV (Arg-Glu-Asp-Val) y p茅ptidos cortos sintetizados RGDS (Arg-Gly-Asp-Ser), REDV, YIGSR (Tyr-Ile-Gly -Ser-Arg) y su combinaci贸n equimolar, fueron anclados por fisisorci贸n y uni贸n covalente a las superficies de la aleaci贸n, se caracterizaron f铆sicamente-qu铆micamente y evalu贸 in vitro con c茅lulas endoteliales de vena umbilical humana (HUVECs), c茅lulas de m煤sculo liso de arteria coronaria (CASMCs) y plaquetas de donantes de sangre. En primer lugar, se desarrollaron y optimizaron las superficies biofuncionalizadas con ELR mediante la evaluaci贸n de diferentes tratamientos de activaci贸n superficial: plasma de ox铆geno y ataque con hidr贸xido de sodio, y diferentes estrategias de uni贸n: fisisorci贸n y uni贸n covalente. Las superficies funcionalizadas demostraron una mayor adhesi贸n celular y propagaci贸n de c茅lulas HUVEC, este efecto se enfatiza a medida que aumenta la cantidad de biomol茅culas inmovilizadas y se relaciona directamente con la t茅cnica de inmovilizaci贸n: la uni贸n covalente. Sin embargo, el proceso de silanizaci贸n no fue completamente efectivo, ya que se observ贸 una mezcla de uniones covalentes y fisisorbidas, probablemente debido al uso de grandes mol茅culas que disminuyeron el control de la uni贸n entre la biomol茅cula y la superficie. En segundo lugar, se inmovilizado los p茅ptidos sintetizados RGDS, REDV, YIGSR y sus combinaciones equimolares sobre las diferentes superficies. Los estudios celulares demostraron que la funcionalizaci贸n covalente de las superficies de CoCr con una combinaci贸n equimolar de RGDS/YIGSR represent贸 la estrategia m谩s potente para potenciar las etapas tempranas de la adhesi贸n, proliferaci贸n y migraci贸n de HUVECs, indicando un efecto sin茅rgico positivo entre los dos motivos pept铆dicos. Adem谩s, la expresi贸n g茅nica y los estudios de adhesi贸n plaquetaria mostraron que las superficies silanizadas con la combinaci贸n RGDS/YIGSR mejoraron la antitrombogenicidad en comparaci贸n con las superficies no modificadas. Finalmente, con los co-cultivos celulares de HUVECs/CASMCs se encontr贸 que la funcionalizaci贸n aumentaba la cantidad de HUVEC adheridas sobre las superficies modificadas en comparaci贸n con CoCr simple, independientemente del p茅ptido usado y la estrategia de inmovilizaci贸n. En general, la presente tesis ofrece una visi贸n completa de la efectividad de la inmovilizaci贸n de mol茅culas adhesivas celulares en la superficie de la aleaci贸n CoCr para mejorar la endotelializaci贸n, mientras que previene la reestenosis y trombosis en aplicaciones cardiovasculares.Postprint (published version

    Cell adhesive peptides functionalized on CoCr alloy stimulate endothelialization and prevent thrombogenesis and restenosis

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    Immobilization of bioactive peptide sequences on CoCr surfaces is an effective route to improve endothelialization, which is of great interest for cardiovascular stents. In this work, we explored the effect of physical and covalent immoblization of RGDS, YIGSR and their equimolar combination peptides on endothelial cells (EC) and smooth muscle cell (SMC) adhesion and on thrombogenicity. We extensively investigated using RT-qPCR, the expression by ECs cultured on functionalised CoCr surfaces of different genes. Genes relevant for adhesion (ICAM-1 and VCAM-1), vascularization (VEGFA, VEGFR-1 and VEGFR-2) and anti-thrombogenicity (tPA and eNOS) were over-expressed in the ECs grown to covalently functionalized CoCr surfaces compared to physisorbed and control surfaces. Pro-thrombogenic genes expression (PAI-1 and vWF) decreased over time. Cell co-cultures of ECs/SMCs found that functionalization increased the amount of adhered ECs onto modified surfaces compared to plain CoCr, independently of the used peptide and the strategy of immobilization. SMCs adhered less compared to ECs in all surfaces. All studied peptides showed a lower platelet cell adhesion compared to TCPS. Covalent functionalization of CoCr surfaces with an equimolar combination of RGDS and YIGSR represented prevailing strategy to enhance the early stages of ECs adhesion and proliferation, while preventing SMCs and platelet adhesion.Postprint (author's final draft

    The LRRC8-mediated volume-regulated anion channel is altered in glaucoma

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    LRRC8; Anion channel; GlaucomaLRRC8; Canal Ani貌nic; GlaucomaLRRC8; Canal Ani贸nico; GlaucomaRegulation of cellular volume is an essential process to balance volume changes during cell proliferation and migration or when intracellular osmolality increases due to transepithelial transport. We previously characterized the key role of volume-regulated anion channels (VRAC) in the modulation of the volume of trabecular meshwork (TM) cells and, in turn, the aqueous humour (AH) outflow from the eye. The balance between the secretion and the drainage of AH determines the intraocular pressure (IOP) that is the major casual risk factor for glaucoma. Glaucoma is an ocular disease that causes irreversible blindness due to the degeneration of retinal ganglion cells. The recent identification of Leucine-Rich Repeat-Containing 8 (LRRC8A-E) proteins as the molecular components of VRAC opens the field to elucidate their function in the physiology of TM and glaucoma. Human TM cells derived from non-glaucomatous donors and from open-angle glaucoma patients were used to determine the expression and the functional activity of LRRC8-mediated channels. Expression levels of LRRC8A-E subunits were decreased in HTM glaucomatous cells compared to normotensive HTM cells. Consequently, the activity of VRAC currents and volume regulation of TM cells were significantly affected. Impaired cell volume regulation will likely contribute to altered aqueous outflow and intraocular pressure

    Pukaras in the Middle Calchaqui Valley (Salta, Argentina): a Few Answers to Old Questions

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    En este trabajo integramos la informaci贸n actualmente disponible para las quebradas altas del valle Calchaqu铆 medio en la provincia de Salta, Argentina, con el objetivo de aportar a la discusi贸n sobre la funcionalidad de asentamientos del tipo pukara del Periodo de Desarrollos Regionales (PDR) en el noroeste de Argentina (NOA). Analizamos la distribuci贸n espacio-temporal de pukaras en una escala micro, con datos procedentes de excavaciones y recolecciones de superficie, a los que sumamos informaci贸n de relatos en fuentes escritas del siglo XVII. Revisamos preconceptos como la exclusividad funcional de asentamiento militar, reductos defensivos, lugares de habitaci贸n permanente, as铆 como la asociaci贸n con 谩reas de cultivo a partir de tres casos de estudio. Considerando que en una escala regional siempre se ha priorizado la informaci贸n generada en la arqueolog铆a del valle troncal del r铆o Calchaqu铆, los datos aqu铆 presentados contribuyen a se帽alar la importancia de las quebradas altas dentro de la historia prehisp谩nica local. Asimismo, nuestros resultados dan sustento a la variabilidad intersitios de una forma de habitar las quebradas altas durante el PDR donde las esferas de lo dom茅stico, ceremonial y defensivo se interpelan.In this article, we synthesize the currently-available information from high-altitude ravines in the middle Calchaqu铆 Valley (Salta Province, Argentina), to contribute to an old debate on the functionality of pukaras during the Regional Developments Period (RDP) in northwestern Argentina. We analyze the spatial-temporal distribution of pukaras at a micro-scale along with data from excavations, surface surveys, and historical documents from the seventeenth century. We review some preconceptions such as the functional exclusivity of military settlements, defensive redoubts, places of permanent residence as well as the frequent association with agricultural fields in the study area, based on three case studies. Our data highlight the importance of the high-altitude ravines in preHispanic history, especially considering that information from the main Calchaqu铆 valley has always predominated in regional models. Furthermore, these case studies show inter-site variability in the way RDP societies inhabited the ravines, where we investigate domestic, ceremonial, and defensive spheres.Fil: Williams, Veronica Isabel. Consejo Nacional de Investigaciones Cient铆ficas y T茅cnicas. Oficina de Coordinaci贸n Administrativa Saavedra 15. Instituto de las Culturas. Universidad de Buenos Aires. Instituto de las Culturas; ArgentinaFil: Villegas, Maria Paula. Consejo Nacional de Investigaciones Cient铆ficas y T茅cnicas. Oficina de Coordinaci贸n Administrativa Saavedra 15. Instituto de las Culturas. Universidad de Buenos Aires. Instituto de las Culturas; ArgentinaFil: Castellanos, Mar铆a Cecilia. Consejo Nacional de Investigaciones Cient铆ficas y T茅cnicas. Oficina de Coordinaci贸n Administrativa Saavedra 15. Instituto de las Culturas. Universidad de Buenos Aires. Instituto de las Culturas; Argentin

    Gesti贸n de la innovaci贸n tecnol贸gica como factor de promoci贸n del emprendimiento en universidades privadas venezolanas

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    The purpose was to analyze the management of technological innovation as a factor for promoting entrepreneurship in Venezuelan private universities. Positivist research and experimental transectional not descriptive, field based on population census managers and university students last academic year for research projects. He used Likert questionnaire whose reliability Cronbach's alpha yielded results of 0.97 and 0.95 in in college students managers. It is concluded that should rise indicators of technological activity management and models of technology transfer to the university environment, by motivating students and inclusion in calls for innovation projects.El prop贸sito fue analizar la gesti贸n de innovaci贸n tecnol贸gica como factor de promoci贸n del emprendimiento en universidades privadas venezolanas. La investigaci贸n positivista de tipo descriptiva, de campo, no experimental y transeccional se bas贸 en censo poblacional de gerentes universitarios y estudiantes del 煤ltimo periodo acad茅mico con proyectos investigativos. Utiliz贸 cuestionario likert, cuya confiabilidad Alfa de Cronbach arroj贸 resultados de 0.97 en gerentes universitarios y 0.95 en estudiantes. Se concluye que deben elevarse los indicadores de gesti贸n de actividad tecnol贸gica y modelos de transferencia tecnol贸gica al entorno universitario, mediante la motivaci贸n a estudiantes e inclusi贸n en convocatorias de proyectos de innovaci贸n

    Yield, nutrient utilization and soil properties in a melon crop amended with wine-distillery waste

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    In Spain, large quantities of wine are produced every year (3,339,700 tonnes in 2011) (FAO, 2011) with the consequent waste generation. During the winemaking process, solid residues like grape stalks are generated, as well as grape marc and wine lees as by-products. According to the Council Regulation (EC) 1493/1999 on the common organization of the wine market, by-products coming from the winery industry must be sent to alcohol-distilleries to generate exhausted grape marc and vinasses. With an adequate composting treatment, these wastes can be applied to soils as a source of nutrients and organic matter. A three-year field experiment (2011, 2012 and 2013) was carried out in Ciudad Real (central Spain) to study the effects of wine-distillery waste compost application in a melon crop (Cucumis melo L.). Melon crop has been traditionally cultivated in this area with high inputs of water and fertilizers, but no antecedents of application of winery wastes are known. In a randomized complete block design, four treatments were compared: three compost doses consisted of 6.7 (D1), 13.3 (D2) and 20 t compost ha-1 (D3), and a control treatment without compost addition (D0). The soil was a shallow sandy-loam (Petrocalcic Palexeralfs) with a depth of 0.60 m and a discontinuous petrocalcic horizon between 0.60 and 0.70 m, slightly basic (pH 8.4), poor in organic matter (0.24%), rich in potassium (410 ppm) and with a medium level of phosphorus (22.1 ppm). During each growing period four harvests were carried out and total and marketable yield (fruits weighting <1 kg or visually rotten were not considered), fruit average weight and fruit number per plant were determined. At the end of the crop cycle, four plants per treatment were sampled and the nutrient content (N, P and K) was determined. Soil samplings (0-30 cm depth) were carried before the application of compost and at the end of each growing season and available N and P, as well as exchangeable K content were analyzed. With this information, an integrated analysis was carried out with the aim to evaluate the suitability of this compost as organic amendment

    Utilizaci贸n del compost de orujo de uva en el cultivo del mel贸n en Castilla-La Mancha

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    En el a帽o 2010 se comenz贸 en el Centro Agrario El Chaparrillo un proyecto de investigaci贸n en colaboraci贸n con la Universidad Polit茅cnica de Madrid y la Universidad de Castilla-La Mancha, teniendo como objetivo principal evaluar el comportamiento como enmienda org谩nica y fertilizante del compost de orujo, obtenido de las vi帽as castellano-manchegas de la zona de Socu茅llamos, en un cultivo de mel贸n. En este art铆culo de muestran los resultados

    Un discurso sanitario para un proyecto pol铆tico. La educaci贸n sanitaria en los medios comunicaci贸n de masas durante el primer franquismo

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    Making used of the radio conferences organized by 芦Jefatura Provincial de Sanidad禄 of M谩laga during 1939 and 1940 on maternal and infant hygiene, which were published, in this study we analyse the relationship between politics and health education. The article show how the popularization of medicine was a resource used by national-syndicalism more than sanitary information for the population during early years of Francoism.El an谩lisis de los discursos expuestos en un ciclo de conferencias radiadas durante los a帽os 1939-1940 en la ciudad de M谩laga sobre higiene materno-infantil, organizado por la Jefatura Provincial de Sanidad, nos permite poner de manifiesto c贸mo se utiliza un recurso como la divulgaci贸n de contenidos sanitarios como parte de un proyecto pol铆tico, el nacional-sindicalismo, al que sirvi贸 como elemento vehiculizador

    Water and nitrogen footprint in an irrigated crop under mineral and organic fertilization

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    In order to establish rational nitrogen (N) application and reduce groundwater contamination, a clearer understanding of the N distribution through the growing season and its balance is crucial. Excessive doses of N and/or water applied to fertigated crops involve a substantial risk of aquifer contamination by nitrate; but knowledge of N cycling and availability within the soil could assist in avoiding this excess. In central Spain, the main horticultural fertigated crop is the melon type ?piel de sapo驴 and it is cultivated in vulnerable zones to nitrate pollution (Directive 91/676/CEE). However, until few years ago there were not antecedents related to the optimization of nitrogen fertilization together with irrigation. Water and N footprint are indicators that allow assessing the impact generated by different agricultural practices, so they can be used to improve the management strategies in fertigated crop systems. The water footprint distinguishes between blue water (sources of water applied to the crop, like irrigation and precipitation), green water (water used by the crop and stored in the soil), and it is furthermore possible to quantify the impact of pollution by calculating the grey water, which is defined as the volume of polluted water created from the growing and production of crops. On the other hand, the N footprint considers green N (nitrogen consumed by the crops and stored in the soil), blue N (N available for crop, like N applied with mineral and/or organic fertilizers, N applied with irrigation water and N mineralized during the crop period), whereas grey N is the amount of N-NO3- washed from the soil to the aquifer. All these components are expressed as the ratio between the components of water or N footprint and the yield (m3 t-1 or kg N t-1 respectively). The objetives of this work were to evaluate the impact derivated from the use of different fertilizer practices in a melon crop using water and N footprint

    Efficiency and environmental indexes to evaluate the sustainability of mineral and organic fertilization in an irrigated melon crop

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    Melon is traditionally cultivated in fertigated farmlands in the center of Spain with high inputs of water and N fertilizer. Excess N can have a negative impact, from the economic point of view, since it can diminish the production and quality of the fruit, from the environmental point of view, since it is a very mobile element in the soil and can contaminate groundwater. From health point of view, nitrate can be accumulated in fruit pulp, and, in addition, groundwater is the fundamental supply source of human populations. Best management practices are particularly necessary in this region as many zones have been declared vulnerable to NO3- pollution (Directive 91/676/CEE) During successive years, a melon crop (Cucumis melo L.) was grown under field conditions applying mineral and organic fertilizers under drip irrigation. Different doses of ammonium nitrate were used as well as compost derived from the wine-distillery industry which is relevant in this area. The present study reviews the most common N efficiency indexes under the different management options with a view to maximizing yield and minimizing N loss
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