Altered glutamatergic and dopaminergic signaling has been proposed as contributing to the specific striatal cell death observed in Huntington's disease (HD). However, the precise mechanisms by which mutant huntingtin sensitize striatal cells to dopamine and glutamate inputs remain unclear. Here, we demonstrate in knock-in HD striatal cells that mutant huntingtin enhances dopaminemediated striatal cell death via dopamine D 1 receptors. Moreover, we show that NMDA receptors specifically potentiate the vulnerability of mutant huntingtin striatal cells to dopamine toxicity as pretreatment with NMDA increased D 1 R-induced cell death in mutant but not wild-type cells. As potential underlying mechanism of increased striatal vulnerability, we identified aberrant cyclin-dependent kinase 5 (Cdk5) activation. We demonstrate that enhanced Cdk5 phosphorylation and increased calpain-mediated conversion of the Cdk5 activator p35 into p25 may account for the deregulation of Cdk5 associated to dopamine and glutamate receptor activation in knock-in HD striatal cells. Moreover, supporting a detrimental role of Cdk5 in striatal cell death, neuronal loss can be widely prevented by roscovitine, a potent Cdk5 inhibitor. Significantly, reduced Cdk5 expression together with enhanced Cdk5 phosphorylation and p25 accumulation also occurs in the striatum of mutant Hdh Q111 mice and HD human brain suggesting the relevance of deregulated Cdk5 pathway in HD pathology. These findings provide new insights into the molecular mechanisms underlying the selective vulnerability of striatal cells in HD and identify p25/Cdk5 as an important mediator of dopamine and glutamate neurotoxicity associated to HD.
To cite this version:Eudald Mujal, Josep Fortuny, Jordi Pérez-Cano, Jaume Dinarès-Turell, Jordi Ibáñez-Insa, et al.. Integrated multi-stratigraphic study of the Coll de Terrers late Permian-Early Triassic continental succession from the Catalan Pyrenees (NE Iberian Peninsula): A geologic reference record for equatorial Pangaea. Global and Planetary Change, Elsevier, 2017, 159, pp
Language, school and immigration AbstractDuring the last decade, linguistic, religious, cultural, ethnic and identity heterogeneity have significantly grown in Spain due to an increasing immigrants population. This is reflected in the educational system, which must confront problems hitherto unknown. In this article, we deal with the relationships between language, school and immigration, giving special emphasis to the factors involved in the acquisition of the language spoken at school. We discuss both the time it takes immigrant students to learn the school language and the role students' initial language has on its acquisition. The discussion is based on review data from international assessments and research work carried out in multilingual school settings. We reflect on its significance for establishing educational policies that take into account the difficulties immigrants have to face to acquire the school language. Finally, we address the new needs of educational systems in relation to some of the challenges posed by intercultural education, and we underline the importance of educational practice to find solutions to the problems that derive from the new situation in schools.
ya que, a diferencia de otros países, no acostumbra a coincidir la lengua escolar y la lengua mayoritaria de uso social. En este artículo presentamos los datos obtenidos en la evaluación de conocimiento de catalán y castellano de 396 alumnos extranjeros de tres grupos lingüísticos, árabe, español y rumano, con diferentes tiempos de estancia al finalizar sexto de primaria, así como los efectos que tienen la lengua familiar y el entorno sociolingüístico en la transferencia de habilidades lingüísticas entre las lenguas que este alumnado aprende en la escuela, catalán y castellano. Las conclusiones señalan que cuando existe continuidad entre la lengua escolar y la lengua del entorno se favorece la transferencia de habilidades lingüísticas con propósitos académicos. Palabras clave: Inmigración, adquisición de segundas lenguas, bilingüismo, plurilingüismo, interdependencia lingüística.
Tea is one of the most widely consumed beverages in the world and represents an important source of antioxidants mainly catechins that confer beneficial effects in reducing the risk of cardiovascular diseases, age-related disorders or cancer. In the central nervous system, oxidative stress caused by increased production of reactive oxygen and nitrogen species represents an important mechanism for neuronal dysfunction and cell loss in different neurodegenerative disorders. The neuroprotective effects of green-tea-derived polyphenols have extensively been demonstrated in different models of neurotoxicity. However, few data have been reported on the antioxidant activity of white tea extracts in the nervous system. In the present study, we demonstrate that white tea extracts protect striatal cell lines against oxidative stress-mediated cell death. The effects of white tea on protection of striatal cell cultures are likely associated with the antioxidant properties of white tea components since neuronal cell loss induced by nonoxidative insults such as D1 dopamine receptor activation cannot be prevented by pre-treatment with white tea. Altogether our results suggest that regular consumption of white tea may contribute to reduce oxidative stress associated with brain injury and be clinically useful for treating age-related and neurodegenerative disorders.
La creación de dispositivos específicos para la acogida del alumnado inmigrante de nueva incorporación a los sistemas educativos occidentales tiene cada día más importancia. Cataluña creó en 2004 las aulas de acogida como un instrumento para fomentar el aprendizaje del catalán y la adaptación escolar del alumnado. Estas aulas se ubican en escuelas e institutos y el profesorado forma parte del claustro. El alumnado desde su llegada al centro escolar reparte su tiempo entre el aula ordinaria y el aula de acogida. El artículo presenta los resultados de la evaluación de las aulas de acogida de la educación primaria el curso [2005][2006]. Se utilizaron dos instrumentos, conocimiento de catalán y adaptación escolar. Los resultados muestran que la adaptación escolar y la lengua familiar del alumnado son dos variables que se deben de considerar para describir el conocimiento lingüístico en catalán del alumnado extranjero. Palabras clave: Aula de acogida, alumnado extranjero, adquisición de segundas lenguas, adaptación escolar. Language support classrooms in PrimaryEducation in Catalonia during academic year 2005-2006: Their effects on knowledge of Catalan language and school adaptation
Recent work on education, based on sociocultural principles, suggest an expansion of the traditional boundaries of learning research that takes into account the multiple spaces and life trajectories that make up experience across our life-worlds. This article focuses specifically on young people’s significant learning experiences in order to illustrate empirically what learning means - i.e. where, with whom and how - in the ‘new ecology of learning’ based on the informalization and informationalization of learning in XXI century. 43 significant learning experiences were identified from four young students who recorded their specific learning experiences during a week by means of a significant learning experiences journal and photographs they took themselves. The results show the presence of informal, everyday, spontaneous activities among the significant learning experiences detected and the use of digital technologies as learning resources; they also reveal the assistance of friends and family in the learning process. In conclusion, this study illustrates how young people in XXI century are involved in a whole range of different activities across different sites and over time.
In situ electroporation of adherent cells provides significant advantages with respect to electroporation systems for suspension cells, such as causing minimal stress to cultured cells and simplifying and saving several steps within the process. In this study, a new electrode assembly design is shown and applied to in situ electroporate adherent cell lines growing in standard multiwell plates. We designed an interdigitated array of electrodes patterned on copper with printed circuit board technology and covered with nickel/gold. Small interelectrode distances were used to achieve effective electroporation with low voltages. Epoxy-based microseparators were constructed to avoid direct contact with the cells and to create more uniform electric fields. The device was successful in the electropermeabilization of two different adherent cell lines, C2C12 and HEK 293, as assessed by the intracellular delivery of the fluorescent dextran FD20S. Additionally, as a collateral effect, we observed cell electrofusion in HEK 293 cells, thus making this device also useful for performing cell fusion. In summary, we show the effectiveness of this minimally invasive device for electroporation of adherent cells cultured in standard multiwell plates. The cheap technologies used in the fabrication process of the electrode assembly indicate potential use as a low-cost, disposable device.
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