Disección de los mecanismos subcelulares responsables del fenómeno de la escalera negativa y la apoptosis en la insuficiencia cardíaca usando un modelo celular

La presente tesis está dirigida a examinar los principales mecanismos responsables de la disfunción contráctil que se observa en el corazón insuficiente. Específicamente, estudiaremos el papel que tiene las alteraciones en el manejo del Ca2+ en el desarrollo de la escalera negativa y en la pérdida de unidades contráctiles por apoptosis, ya que ambos fenómenos son de fundamental importancia en el deterioro de la función contráctil en la insuficiencia cardíaca. Esta disfunción contráctil que presentan los corazones insuficientes revela la incapacidad de los mismos para aumentar la fuerza de contracción frente a una mayor demanda, de modo que comprender las bases subcelulares y moleculares de estos fenómenos puede resultar en un importante avance en el desarrollo de nuevas herramientas terapéuticas. Esta tesis describe por lo tanto los resultados de dos trabajos experimentales, que aunque diferentes, están relacionados entre sí por un denominador común que es la disfunción contráctil de la insuficiencia cardíaca (IC). En el primero de ellos, el objetivo fue reproducir a nivel de un miocito cardíaco las tres alteraciones del acoplamiento éxcito contráctil (AEC) que se describen clásicamente en la mayor parte de los modelos de IC (disminución en la expresión de la SERCA2a, aumento en la expresión del NCX y aumento del la concentración de Na+ intracelular) y determinar si éstas mimetizan, asociadas o independientemente, una de las principales características de la IC como es el fenómeno de la escalera negativa. En el segundo, el propósito fue examinar si existe alguna relación entre estas alteraciones en el AEC y la apoptosis, que como ya se mencionó previamente, es una causa fundamental de la disminución de la contractilidad en la IC. Debido a que la disminución en la expresión del NCX (y no su aumento como ocurre en la IC) y la sobreexpresión de SERCA2a (y no su disminución, como ocurre en la IC) se asociaron a apoptosis, (Miyamoto, 2005; Vafiadaki, 2009), nos concentramos en el estudio del posible rol del aumento del Na+ intracelular en la producción de este tipo de muerte celular.Tesis digitalizada en SEDICI gracias a la colaboración de su autora.Facultad de Ciencias Médica

Disección de los mecanismos subcelulares responsables del fenómeno de la escalera negativa y la apoptosis en la insuficiencia cardíaca usando un modelo celular

La presente tesis está dirigida a examinar los principales mecanismos responsables de la disfunción contráctil que se observa en el corazón insuficiente. Específicamente, estudiaremos el papel que tiene las alteraciones en el manejo del Ca2+ en el desarrollo de la escalera negativa y en la pérdida de unidades contráctiles por apoptosis, ya que ambos fenómenos son de fundamental importancia en el deterioro de la función contráctil en la insuficiencia cardíaca. Esta disfunción contráctil que presentan los corazones insuficientes revela la incapacidad de los mismos para aumentar la fuerza de contracción frente a una mayor demanda, de modo que comprender las bases subcelulares y moleculares de estos fenómenos puede resultar en un importante avance en el desarrollo de nuevas herramientas terapéuticas. Esta tesis describe por lo tanto los resultados de dos trabajos experimentales, que aunque diferentes, están relacionados entre sí por un denominador común que es la disfunción contráctil de la insuficiencia cardíaca (IC). En el primero de ellos, el objetivo fue reproducir a nivel de un miocito cardíaco las tres alteraciones del acoplamiento éxcito contráctil (AEC) que se describen clásicamente en la mayor parte de los modelos de IC (disminución en la expresión de la SERCA2a, aumento en la expresión del NCX y aumento del la concentración de Na+ intracelular) y determinar si éstas mimetizan, asociadas o independientemente, una de las principales características de la IC como es el fenómeno de la escalera negativa. En el segundo, el propósito fue examinar si existe alguna relación entre estas alteraciones en el AEC y la apoptosis, que como ya se mencionó previamente, es una causa fundamental de la disminución de la contractilidad en la IC. Debido a que la disminución en la expresión del NCX (y no su aumento como ocurre en la IC) y la sobreexpresión de SERCA2a (y no su disminución, como ocurre en la IC) se asociaron a apoptosis, (Miyamoto, 2005; Vafiadaki, 2009), nos concentramos en el estudio del posible rol del aumento del Na+ intracelular en la producción de este tipo de muerte celular.Tesis digitalizada en SEDICI gracias a la colaboración de su autora.Facultad de Ciencias Médica

Angiotensin II-induced oxidative stress resets the Ca2+ dependence of Ca2+-calmodulin protein kinase II and promotes a death pathway conserved across different species

Rationale: Angiotensin (Ang) II-induced apoptosis was reported to be mediated by different signaling molecules. Whether these molecules are either interconnected in a single pathway or constitute different and alternative cascades by which Ang II exerts its apoptotic action, is not known. Objective: To investigate in cultured myocytes from adult cat and rat, 2 species in which Ang II has opposite inotropic effects, the signaling cascade involved in Ang II-induced apoptosis. Methods and results: Ang II (1 μmol/L) reduced cat/rat myocytes viability by ≈40%, in part, because of apoptosis (TUNEL/caspase-3 activity). In both species, apoptosis was associated with reactive oxygen species (ROS) production, Ca2+/calmodulin-dependent protein kinase (CaMK)II, and p38 mitogen-activated protein kinase (p38MAPK) activation and was prevented by the ROS scavenger MPG (2-mercaptopropionylglycine) or the NADPH oxidase inhibitor DPI (diphenyleneiodonium) by CaMKII inhibitors (KN-93 and AIP [autocamtide 2-related inhibitory peptide]) or in transgenic mice expressing a CaMKII inhibitory peptide and by the p38MAPK inhibitor, SB202190. Furthermore, p38MAPK overexpression exacerbated Ang II-induced cell mortality. Moreover, although KN-93 did not affect Ang II-induced ROS production, it prevented p38MAPK activation. Results further show that CaMKII can be activated by Ang II or H2O2, even in the presence of the Ca 2+chelator BAPTA-AM, in myocytes and in EGTA-Ca2-free solutions in the presence of the calmodulin inhibitor W-7 in in vitro experiments. Conclusions: (1) The Ang II-induced apoptotic cascade converges in both species, in a common pathway mediated by ROS-dependent CaMKII activation which results in p38MAPK activation and apoptosis. (2) In the presence of Ang II or ROS, CaMKII may be activated at subdiastolic Ca2+concentrations, suggesting a new mechanism by which ROS reset the Ca2+dependence of CaMKII to extremely low Ca2+levels.Facultad de Ciencias Médica

Angiotensin II-induced oxidative stress resets the Ca2+ dependence of Ca2+-calmodulin protein kinase II and promotes a death pathway conserved across different species

Rationale: Angiotensin (Ang) II-induced apoptosis was reported to be mediated by different signaling molecules. Whether these molecules are either interconnected in a single pathway or constitute different and alternative cascades by which Ang II exerts its apoptotic action, is not known. Objective: To investigate in cultured myocytes from adult cat and rat, 2 species in which Ang II has opposite inotropic effects, the signaling cascade involved in Ang II-induced apoptosis. Methods and results: Ang II (1 μmol/L) reduced cat/rat myocytes viability by ≈40%, in part, because of apoptosis (TUNEL/caspase-3 activity). In both species, apoptosis was associated with reactive oxygen species (ROS) production, Ca2+/calmodulin-dependent protein kinase (CaMK)II, and p38 mitogen-activated protein kinase (p38MAPK) activation and was prevented by the ROS scavenger MPG (2-mercaptopropionylglycine) or the NADPH oxidase inhibitor DPI (diphenyleneiodonium) by CaMKII inhibitors (KN-93 and AIP [autocamtide 2-related inhibitory peptide]) or in transgenic mice expressing a CaMKII inhibitory peptide and by the p38MAPK inhibitor, SB202190. Furthermore, p38MAPK overexpression exacerbated Ang II-induced cell mortality. Moreover, although KN-93 did not affect Ang II-induced ROS production, it prevented p38MAPK activation. Results further show that CaMKII can be activated by Ang II or H2O2, even in the presence of the Ca 2+chelator BAPTA-AM, in myocytes and in EGTA-Ca2-free solutions in the presence of the calmodulin inhibitor W-7 in in vitro experiments. Conclusions: (1) The Ang II-induced apoptotic cascade converges in both species, in a common pathway mediated by ROS-dependent CaMKII activation which results in p38MAPK activation and apoptosis. (2) In the presence of Ang II or ROS, CaMKII may be activated at subdiastolic Ca2+concentrations, suggesting a new mechanism by which ROS reset the Ca2+dependence of CaMKII to extremely low Ca2+levels.Facultad de Ciencias Médica

Geometry and evolution of a fault-controlled Quaternary basin by means of TDEM and single-station ambient vibration surveys: The example of the 2009 L'Aquila earthquake area, central Italy

We applied a joint survey approach integrating time domain electromagnetic soundings and single-station ambient vibration surveys in the Middle Aterno Valley (MAV), an intermontane basin in central Italy and the locus of the 2009 L’Aquila earthquake. By imaging the buried interface between the infilling deposits and the top of the pre-Quaternary bedrock, we reveal the 3-D basin geometry and gain insights into the long-term basin evolution. We reconstruct a complex subsurface architecture, characterized by three main depocenters separated by thresholds. Basin infill thickness varies from ~200–300m in the north to more than 450m to the southeast. Our subsurface model indicates a strong structural control on the architecture of the basin and highlights that the MAV experienced considerable modifications in its configuration over time. The buried shape of the MAV suggests a recent and still ongoing predominant tectonic control by the NW-SE trending Paganica-San Demetrio Fault System (PSDFS), which crosscuts older ~ENE and NNE trending extensional faults. Furthermore, we postulate that the present-day arrangement of the PSDFS is the result of the linkage of two previously isolated fault segments. We provide constraints on the location of the southeastern boundary of the PSDFS, defining an overall ~19 km long fault system characterized by a considerable seismogenetic potential and a maximum expected magnitude larger than M6.5. This study emphasizes the benefit of combining two easily deployable geophysical methods for reconstructing the 3-D geometry of a tectonically controlled basin. Our joint approach provided us with a consistent match between these two independent estimations of the basin substratum depth within 15%.Published2236–22597T. Struttura della Terra e geodinamica2TR. Ricostruzione e modellazione della struttura crostaleJCR Journa

Angiotensin II-induced oxidative stress resets the Ca2+ dependence of Ca2+-calmodulin protein kinase II and promotes a death pathway conserved across different species

Rationale: Angiotensin (Ang) II-induced apoptosis was reported to be mediated by different signaling molecules. Whether these molecules are either interconnected in a single pathway or constitute different and alternative cascades by which Ang II exerts its apoptotic action, is not known. Objective: To investigate in cultured myocytes from adult cat and rat, 2 species in which Ang II has opposite inotropic effects, the signaling cascade involved in Ang II-induced apoptosis. Methods and results: Ang II (1 μmol/L) reduced cat/rat myocytes viability by ≈40%, in part, because of apoptosis (TUNEL/caspase-3 activity). In both species, apoptosis was associated with reactive oxygen species (ROS) production, Ca2+/calmodulin-dependent protein kinase (CaMK)II, and p38 mitogen-activated protein kinase (p38MAPK) activation and was prevented by the ROS scavenger MPG (2-mercaptopropionylglycine) or the NADPH oxidase inhibitor DPI (diphenyleneiodonium) by CaMKII inhibitors (KN-93 and AIP [autocamtide 2-related inhibitory peptide]) or in transgenic mice expressing a CaMKII inhibitory peptide and by the p38MAPK inhibitor, SB202190. Furthermore, p38MAPK overexpression exacerbated Ang II-induced cell mortality. Moreover, although KN-93 did not affect Ang II-induced ROS production, it prevented p38MAPK activation. Results further show that CaMKII can be activated by Ang II or H2O2, even in the presence of the Ca 2+chelator BAPTA-AM, in myocytes and in EGTA-Ca2-free solutions in the presence of the calmodulin inhibitor W-7 in in vitro experiments. Conclusions: (1) The Ang II-induced apoptotic cascade converges in both species, in a common pathway mediated by ROS-dependent CaMKII activation which results in p38MAPK activation and apoptosis. (2) In the presence of Ang II or ROS, CaMKII may be activated at subdiastolic Ca2+concentrations, suggesting a new mechanism by which ROS reset the Ca2+dependence of CaMKII to extremely low Ca2+levels.Facultad de Ciencias Médica

Imaging the three-dimensional architecture of the Middle Aterno basin (2009 L’Aquila earthquake, Central Italy) using ground TDEM and seismic noise surveys: preliminary results

We present preliminary results from a multidisciplinary geophysical approach applied to the imaging of the threedimensional architecture of the Middle Aterno basin, close to the epicentral area of the 2009 L’Aquila earthquake (central Italy). We collected several time domain electromagnetic soundings (TDEM) coupled with seismic noise measurements focusing on the characterization of the bedrock/infill interface. Our preliminary results agree with existing geophysical data collected in the area, and show that the southeastern portion of the basin is characterized by a deepening of the Mesozoic-Tertiary bedrock down to a depth of more than 450 m. We found that a joint use of electromagnetic and seismic methods significantly contributes in obtaining new insights on the 3D geometry of the Middle Aterno basin. Moreover, we believe that our combined approach based on TDEM and noise measurements can be adopted to investigate similar geological settings elsewhere.PublishedPescina, Fucino Basin, Italy2T. Tettonica attiva7A. Geofisica di esplorazioneope

Imaging the three-dimensional architecture of the Middle Aterno basin (2009 L’Aquila earthquake, Central Italy) using ground TDEM and seismic noise surveys: preliminary results

We present preliminary results from a multidisciplinary geophysical approach applied to the imaging of the threedimensional architecture of the Middle Aterno basin, close to the epicentral area of the 2009 L’Aquila earthquake (central Italy). We collected several time domain electromagnetic soundings (TDEM) coupled with seismic noise measurements focusing on the characterization of the bedrock/infill interface. Our preliminary results agree with existing geophysical data collected in the area, and show that the southeastern portion of the basin is characterized by a deepening of the Mesozoic-Tertiary bedrock down to a depth of more than 450 m. We found that a joint use of electromagnetic and seismic methods significantly contributes in obtaining new insights on the 3D geometry of the Middle Aterno basin. Moreover, we believe that our combined approach based on TDEM and noise measurements can be adopted to investigate similar geological settings elsewhere

Perfil do consumidor das modalidades de ondas no contexto sócio-económico da região da Ericeira

Mestrado em Gestão do Desporto - Organizações DesportivasA presente investigação resulta da necessidade de estudar o consumo das modalidades de ondas em Portugal, visto estarem em constante crescimento no nosso país. Neste sentido é estabelecido como principal objectivo o estudo do perfil social e económico do consumidor de modalidades de ondas na região da Ericeira, um emblema nacional, e os efeitos do recente galardão de Reserva Mundial de Surf atribuído à região nos hábitos dos consumidores das modalidades de ondas. Realçamos como primordiais resultados as seguintes características relativas ao consumidor das modalidades de ondas da região: indivíduos do género masculino, com idade compreendida entre os 26 e 35 anos e elegendo entre as modalidades de ondas a pratica do Surf. Do ponto de vista económico sabemos que diariamente em média o consumidor gasta 20,88 euros com estadia, 15,52 euros em refeições, entre 10 euros e 30 euros por aula de Surf, 20,99 euros no comércio local e 13,16 euros em outras experiências. Concluímos assim que a região da Ericeira apresenta condições para consubstanciar o seu desenvolvimento económico em torno do consumo das modalidades de ondas, razão pela qual, em nosso entender, as maiores marcas de surf a nível mundial têm efectuado volumosos investimentos na região