946 resultados para ACU(3)RU(4)O(12)


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Study Design. In vitro study to develop an intervertebral disc degeneration (IDD) organ culture model, using coccygeal bovine intervertebral discs (IVDs) and injection of proteolytic enzymes MMP-3, ADAMTS-4 and HTRA1.Objective. This study aimed to develop an in-vitro model of enzyme-mediated IDD to mimic the clinical outcome in humans for investigation of therapeutic treatment options.Summary of Background Data. Bovine IVDs are comparable to human IVDs in terms of cell composition and biomechanical behavior. Researchers injected papain and trypsin into them to create an IDD model with a degenerated nucleus pulposus (NP) area. They achieved macroscopic cavities as well as a loss of glycosaminoglycans (GAGs). However, none of these enzymes are clinically relevant.Methods. Bovine IVDs were harvested maintaining the endplates. Active forms of MMP-3, ADAMTS-4 and HTRA1 were injected at a dose of 10μg/ml each. Phosphate buffered saline (PBS) was injected as a control. Discs were cultured for 8 days and loaded diurnally (day 1 to day 4 with 0.4 MPa for 16 h) and left under free swelling condition from day 4 to day 8 to avoid expected artifacts due to dehydration of the NP. Outcome parameters included disc height, metabolic cell activity, DNA content, glycosaminoglycan (GAG) content, total collagen content, relative gene expression and histological investigation.Results. The mean metabolic cell activity was significantly lower in the NP area of discs injected with ADAMTS-4 compared to the day 0 control discs. Disc height was decreased following injection with HTRA1, and was significantly correlated with changes in GAG/DNA of the NP tissue. Total collagen content tended to be lower in groups injected with ADAMTS4 and MMP-3.Conclusion. MMP-3, ADAMTS-4 and HTRA1 neither provoked visible matrix degradation nor major shifts in gene expression. However, cell activity was significantly reduced and HTRA1 induced loss of disc height which positively correlated with changes in GAG/DNA content. The use of higher doses of these enzymes or a combination thereof may therefore be necessary to induce disc degeneration

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Changes in (1→3,1→4)-β-D-glucan endohydrolase (EC 3.2.1.73) protein levels were investigated in segments from second leaves of wheat (Triticum aestivum L.). The abundance of the enzyme protein markedly increased when leaf segments were incubated in the dark whereas the enzyme rapidly disappeared when dark-incubated segments were illuminated or fed with sucrose. Addition of cycloheximide (CHI) to the incubation medium led to the disappearance of previously synthesized (1→3,1→4)-β-glucanase and suppressed the dark-induced accumulation indicating that the enzyme was rather unstable. The degradation of (1→3,1→4)-β-glucanase was analyzed without the interference of de-novo synthesis in intercellular washing fluid (IWF). The loss of the enzyme protein during incubation of IWF (containing naturally present peptide hydrolases) indicated that the stability increased from pH 4 to pH 7 and that an increase in the temperature from 25 to 35 °C considerably decreased the stability. Chelating divalent cations in the IWF with o-phenanthroline also resulted in a lowered stability of the enzyme. A strong temperature effect in the range from 25 to 35 °C was also observed in wheat leaf segments. Diurnal changes in (1→3,1→4)-β-glucanase activity were followed in intact second leaves from young wheat plants. At the end of the dark period, the activity was high but constantly decreased during the light phase and remained low if the light period was extended. Activity returned to the initial level during a 10-h dark phase. During a diurnal cycle, changes in (1→3,1→4)-β-glucanase activity were associated with reciprocal changes in soluble carbohydrates. The results suggest that the synthesis and the proteolytic degradation of an apoplastic enzyme may rapidly respond to changing environmental conditions.

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Wilhelm Bacher

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La actual provincia de Misiones desarrolló una economía relacionada a cultivos industriales, particularmente yerba mate y tabaco. El sistema productivo se enlazó a ellos, los cuales además modelaron las explotaciones agrícolas y al sujeto social agrario. El objetivo de este trabajo es analizar las acciones colectivas desplegadas por el cooperativismo yerbatero misionero y la representación de intereses del sector, tomando como referente a la Federación de Cooperativas Agrícolas de Misiones (Fedecoop); las mismas serán puestas en relación con los cambios en las políticas estatales a partir de la década de 1950 hasta 1976. Se sostiene la hipótesis de que las cooperativas promueven una organización económica y social válida para los sujetos rurales del agro misionero. Para este análisis histórico, interesa considerar la construcción de hegemonía, entrelazados con el vínculo existente entre los proyectos productivos y sociales que sostenía el sujeto cooperativo y aquél que el Estado intentó reformular al finalizar el gobierno peronista en 1955. El propósito es ponderar cuáles fueron las consecuencias de los cambios ocurridos a partir del paso de un Estado interventor a uno burocrático autoritario sobre el movimiento cooperativo.

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El presente artículo es el resultado de la articulación del producto de dos investigaciones llevadas a cabo entre los años 2009-2010 y 2011-2013 en la ciudad de Posadas Misiones. En la primera investigación, “Análisis de los efectos de la aplicación de programas compensatorios en las instituciones educativas de Posadas y en las condiciones laborales docentes. Período 2005-2010” se registraron las diferentes representaciones que directivos y docentes tenían acerca de los sujetos de aprendizaje y sus familias lo que motivó a efectuar la segunda investigación, “Importancia que le asignan las familias en condición de pobreza a la educación”, a los efectos de obtener la mirada de las familias en relación a la escuela, docentes y directivos así como sobre los planes sociales.

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En el presente artículo proponemos una aproximación al desafío que representa construir una Educación Intercultural Bilingüe en una aldea Mbya Guaraní, Jakutinga (Yacutinga), Municipio de Gobernador Roca, Misiones. Partimos de una introducción a la cuestión educativa para centrarnos luego en la Escuela Provincial N° 659 “Padre Antonio Sepp” donde conviven niños de la aldea Mbya y “criollos” o de la sociedad nacional conformando una escuela de matrícula “mixta”. Muchas de las dimensiones aquí problematizadas se encuentran aún en elaboración, las consideramos introductorias a lo que posteriormente abordaremos en una Tesina de Grado que tratará sobre las relaciones entre los niños indígenas y no indígenas, sus docentes y Auxiliares Docentes Indígenas, el pasaje de la comunidad a la escuela y la implementación de la modalidad E.I.B centrando nuestra mirada en el Nivel Inicial.