39 research outputs found

    Id2 leaves the chromatin of the E2F4-p130-controlled c-myc promoter during hepatocyte priming for liver regeneration

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    The Id (inhibitor of DNA binding or inhibitor of differentiation) helix-loop-helix proteins are involved in the regulation of cell growth, differentiation and cancer. The fact that the molecular mechanisms of liver regeneration are not completely understood prompted us to study the fate of Id2 in proliferating liver. Id2 increases in liver regeneration after partial hepatectomy, following the early induction of its gene. Co-immunoprecipitation shows that Id2 forms a complex with E2F4, p130 and mSin3A in quiescent liver and all these components are present at the c-myc promoter as shown using ChIP (chromatin immunoprecipitation). Activation of c-myc during hepatocyte priming (G0-G1 transition) correlates with the dissociation of Id2 and HDAC (histone deacetylase), albeit p130 remains bound at least until 6 h. Moreover, as the G0-G1 transition progresses, Id2 and HDAC again bind the c-myc promoter concomitantly with the repression of this gene. The time course of c-myc binding to the Id2 promoter, as determined by ChIP assays is compatible with a role of the oncoprotein as a transcriptional inducer of Id2 in liver regeneration. Immunohistochemical analysis shows that Id2 also increases in proliferating hepatocytes after bile duct ligation. In this case, the pattern of Id2 presence in the c-myc promoter parallels that found in regenerating liver. Our results may suggest a control role for Id2 in hepatocyte priming, through a p130 dissociation-independent regulation of c-my

    Resultados del estudio geológico a escala 1/25.000 del término municipal de Madrid.

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    Se exponen de forma abreviada los rasgos en cuanto a metodología y conclusiones del estudio geológico a escala 1/25000 realizado en el Municipio de Madrid en los años 1982/83. Las diferentes unidades expresadas en la cartografiase describen en función de las pautas mayores observables en los materiales que forman cada una de ellas, analizándose sus relaciones estratigráficas. El Proyecto «Estudio Geológico a escala 1/25000 del Término Municipal de Madrid ha sido llevado a cabo a lo largo de los años 1982-83 como resultado de la colaboración científica entre diversos organismos de la Administración (Facultad de CC. Geológicas-Universidad Complutense, Instituto Geológico y Minero. Ayuntamiento de Madrid, Instituto de Geología de Madrid-CSIC, y otros). Constituye una de las áreas de actuación definidas dentro del Convenio de Colaboración Técnica y Cultural para el conocimiento de las Características del Suelo y Subsuelo de Madrid», propiciado y patrocinado por el Excmo. Ayuntamiento. La financiación del proyecto especifico de Geología ha sido realizada íntegramente por el IGME, organismo encargado además de su supervisión. El desarrollo del Proyecto tiene un marcado carácter interdisciplinar, fruto del trasvase de información entre los distintos grupos que abarca el Convenio general (aparte de los ya referidos, el SGOP, COPLACO, Laboratorio «José Luis Escario» siendo precisamente uno de los objetivos del trabajo el servir de apoyo a las restantes áreas de investigación. Los estudios geológicos realizados se plasman en un total de siete mapas a escala 1/25000 elaborados según la normativa Magna de cartografía geológica mapas que toman como referencia, aunque en algunos casos no las completan y en otros adosan porciones de hojas adyacentes, las hojas 1/25000 de Madrid, Alcorcón, El Pardo, San Femando de Henares, Pozuelo de Alarcón, Alcobendas y Castillo de Viñuelas

    The Aguablanca Ni–(Cu) sulfide deposit, SW Spain: geologic and geochemical controls and the relationship with a midcrustal layered mafic complex

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    The Aguablanca Ni–(Cu) sulfide deposit is hosted by a breccia pipe within a gabbro–diorite pluton. The deposit probably formed due to the disruption of a partially crystallized layered mafic complex at about 12– 19 km depth and the subsequent emplacement of melts and breccias at shallow levels (<2 km). The ore-hosting breccias are interpreted as fragments of an ultramafic cumulate, which were transported to the near surface along with a molten sulfide melt. Phlogopite Ar–Ar ages are 341– 332 Ma in the breccia pipe, and 338–334 Ma in the layered mafic complex, and are similar to recently reported U–Pb ages of the host Aguablanca Stock and other nearby calcalkaline metaluminous intrusions (ca. 350–330 Ma). Ore deposition resulted from the combination of two critical factors, the emplacement of a layered mafic complex deep in the continental crust and the development of small dilational structures along transcrustal strike-slip faults that triggered the forceful intrusion of magmas to shallow levels. The emplacement of basaltic magmas in the lower middle crust was accompanied by major interaction with the host rocks, immiscibility of a sulfide melt, and the formation of a magma chamber with ultramafic cumulates and sulfide melt at the bottom and a vertically zoned mafic to intermediate magmas above. Dismembered bodies of mafic/ultramafic rocks thought to be parts of the complex crop out about 50 km southwest of the deposit in a tectonically uplifted block (Cortegana Igneous Complex, Aracena Massif). Reactivation of Variscan structures that merged at the depth of the mafic complex led to sequential extraction of melts, cumulates, and sulfide magma. Lithogeochemistry and Sr and Nd isotope data of the Aguablanca Stock reflect the mixing from two distinct reservoirs, i.e., an evolved siliciclastic middle-upper continental crust and a primitive tholeiitic melt. Crustal contamination in the deep magma chamber was so intense that orthopyroxene replaced olivine as the main mineral phase controlling the early fractional crystallization of the melt. Geochemical evidence includes enrichment in SiO2 and incompatible elements, and Sr and Nd isotope compositions (87Sr/86Sri 0.708–0.710; 143Nd/144Ndi 0.512–0.513). However, rocks of the Cortegana Igneous Complex have low initial 87Sr/86Sr and high initial 143Nd/144Nd values suggesting contamination by lower crustal rocks. Comparison of the geochemical and geological features of igneous rocks in the Aguablanca deposit and the Cortegana Igneous Complex indicates that, although probably part of the same magmatic system, they are rather different and the rocks of the Cortegana Igneous Complex were not the direct source of the Aguablanca deposit. Crust–magma interaction was a complex process, and the generation of orebodies was controlled by local but highly variable factors. The model for the formation of the Aguablanca deposit presented in this study implies that dense sulfide melts can effectively travel long distances through the continental crust and that dilational zones within compressional belts can effectively focus such melt transport into shallow environments

    Epigenetic Transcriptional Regulation of the Growth Arrest-Specific gene 1 (Gas1) in Hepatic Cell Proliferation at Mononucleosomal Resolution

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    BACKGROUND: Gas1 (growth arrest-specific 1) gene is known to inhibit cell proliferation in a variety of models, but its possible implication in regulating quiescence in adult tissues has not been examined to date. The knowledge of how Gas1 is regulated in quiescence may contribute to understand the deregulation occurring in neoplastic diseases. METHODOLOGY/PRINCIPAL FINDINGS: Gas1 expression has been studied in quiescent murine liver and during the naturally synchronized cell proliferation after partial hepatectomy. Chromatin immunoprecipitation at nucleosomal resolution (Nuc-ChIP) has been used to carry out the study preserving the in vivo conditions. Transcription has been assessed at real time by quantifying the presence of RNA polymerase II in coding regions (RNApol-ChIP). It has been found that Gas1 is expressed not only in quiescent liver but also at the cell cycle G(1)/S transition. The latter expression peak had not been previously reported. Two nucleosomes, flanking a nucleosome-free region, are positioned close to the transcription start site. Both nucleosomes slide in going from the active to the inactive state and vice versa. Nuc-ChIP analysis of the acquisition of histone epigenetic marks show distinctive features in both active states: H3K9ac and H3K4me2 are characteristic of transcription in G(0) and H4R3me2 in G(1)/S transition. Sequential-ChIP analysis revealed that the "repressing" mark H3K9me2 colocalize with several "activating" marks at nucleosome N-1 when Gas1 is actively transcribed suggesting a greater plasticity of epigenetic marks than proposed until now. The recruitment of chromatin-remodeling or modifying complexes also displayed distinct characteristics in quiescence and the G(1)/S transition. CONCLUSIONS/SIGNIFICANCE: The finding that Gas1 is transcribed at the G(1)/S transition suggests that the gene may exert a novel function during cell proliferation. Transcription of this gene is modulated by specific "activating" and "repressing" epigenetic marks, and by chromatin remodeling and histone modifying complexes recruitment, at specific nucleosomes in Gas1 promoter

    La renovación de la palabra en el bicentenario de la Argentina : los colores de la mirada lingüística

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    El libro reúne trabajos en los que se exponen resultados de investigaciones presentadas por investigadores de Argentina, Chile, Brasil, España, Italia y Alemania en el XII Congreso de la Sociedad Argentina de Lingüística (SAL), Bicentenario: la renovación de la palabra, realizado en Mendoza, Argentina, entre el 6 y el 9 de abril de 2010. Las temáticas abordadas en los 167 capítulos muestran las grandes líneas de investigación que se desarrollan fundamentalmente en nuestro país, pero también en los otros países mencionados arriba, y señalan además las áreas que recién se inician, con poca tradición en nuestro país y que deberían fomentarse. Los trabajos aquí publicados se enmarcan dentro de las siguientes disciplinas y/o campos de investigación: Fonología, Sintaxis, Semántica y Pragmática, Lingüística Cognitiva, Análisis del Discurso, Psicolingüística, Adquisición de la Lengua, Sociolingüística y Dialectología, Didáctica de la lengua, Lingüística Aplicada, Lingüística Computacional, Historia de la Lengua y la Lingüística, Lenguas Aborígenes, Filosofía del Lenguaje, Lexicología y Terminología

    Reciclaje de los materiales desechados en las edificaciones que se construyen en la ciudad de Azogues

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    Para darle un tratamiento a los deshechos de las construcciones se realizó un estudio de impactos ambientales, que contiene análisis de paisajes, suelo y aire, confirmando sus características contaminantes. Se realizó un muestreo de edificación, de la cual se recicló el material y se registraron los resultados de cada una luego establecimos un proceso artesanal para determinar los componentes del desecho y sus cantidades. Un paso posterior consiste en determinar las características físico-químicas y mecánicas, obteniendo resultados direccionados a elaborar tabiquerías. Finalmente se elaboró bloques y paneles, realizando las pruebas respectivas y obteniendo resultados satisfactoriosArquitectoCuenc

    The worldwide epilepsy treatment gap: a systematic review and recommendations for revised definitions – a report from the ILAE epidemiology commission

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    Objective: In order to more appropriately apply and understand the “epilepsy treatment gap” (ETG) concept in current health systems, revised conceptual and operational definitions of ETG are timely and necessary. This article therefore systematically reviews worldwide studies of the ETG, distinguishing high-, middle-, and low-income regions, and provides recommendations for an updated International League Against Epilepsy (ILAE) definition of ETG. Methods: A systematic review of the ETG was performed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standards. The search was conducted from January 1990 to July 2019, in the online databases of Ovid MEDLINE and Embase. Identified abstracts were reviewed in duplicate and data independently extracted using a standard proforma. Data describing treatment gap information including both diagnostic and therapeutic aspects of access to epilepsy treatment were recorded. Descriptive statistics are presented. Results: The treatment gap reported in the 45 distinctive populations represented 33 countries. Treatment gap definitions varied widely. The reported ETGs ranged broadly from 5.6% in Norway to 100% in parts of Tibet, Togo, and Uganda. The wide range of reported ETGs was multifactorial in origin including true differences in the availability and utilization of health care among study populations, variations in operational definitions of the epilepsy treatment gap, and methodological differences in sampling and identifying representative epilepsy cases in populations. Significance and recommendations For the ETG to be a useful metric to compare levels of unmet epilepsy care across different countries and regions, a standardized definition must be adapted, recognizing some of the limitations of the current definitions. Our proposed definition takes into account the lack of effective health care insurance, the diagnostic gap, the therapeutic gap, quality-of-care, and other unmet health care needs.”
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