57 resultados para Epithelial to mesenchymal transition
em Consorci de Serveis Universitaris de Catalunya (CSUC), Spain
Resumo:
Molecular characterization of radical prostatectomy specimens after systemic therapy may identify a gene expression profile for resistance to therapy. This study assessed tumor cells from patients with prostate cancer participating in a phase II neoadjuvant docetaxel and androgen deprivation trial to identify mediators of resistance. Transcriptional level of 93 genes from a docetaxel-resistant prostate cancer cell lines microarray study was analyzed by TaqMan low-density arrays in tumors from patients with high-risk localized prostate cancer (36 surgically treated, 28 with neoadjuvant docetaxel þ androgen deprivation). Gene expression was compared between groups and correlated with clinical outcome. VIM, AR and RELA were validated by immunohistochemistry. CD44 and ZEB1 expression was tested by immunofluorescence in cells and tumor samples. Parental and docetaxel-resistant castration-resistant prostate cancer cell lines were tested for epithelial-to-mesenchymal transition (EMT) markers before and after docetaxel exposure. Reversion of EMT phenotype was investigated as a docetaxel resistance reversion strategy. Expression of 63 (67.7%) genes differed between groups (P < 0.05), including genes related to androgen receptor, NF-k B transcription factor, and EMT. Increased expression of EMT markers correlated with radiologic relapse. Docetaxel-resistant cells had increased EMT and stem-like cell markers expression. ZEB1 siRNA transfection reverted docetaxel resistance and reduced CD44 expression in DU-145R and PC-3R. Before docetaxel exposure, a selected CD44 þ subpopulation of PC-3 cells exhibited EMT phenotype and intrinsic docetaxel resistance; ZEB1/CD44 þ subpopulations were found in tumor cell lines and primary tumors; this correlated with aggressive clinical behavior. This study identifies genes potentially related to chemotherapy resistance and supports evi-dence of the EMT role in docetaxel resistance and adverse clinical behavior in early prostate cancer.
Resumo:
Molecular characterization of radical prostatectomy specimens after systemic therapy may identify a gene expression profile for resistance to therapy. This study assessed tumor cells from patients with prostate cancer participating in a phase II neoadjuvant docetaxel and androgen deprivation trial to identify mediators of resistance. Transcriptional level of 93 genes from a docetaxel-resistant prostate cancer cell lines microarray study was analyzed by TaqMan low-density arrays in tumors from patients with high-risk localized prostate cancer (36 surgically treated, 28 with neoadjuvant docetaxel þ androgen deprivation). Gene expression was compared between groups and correlated with clinical outcome. VIM, AR and RELA were validated by immunohistochemistry. CD44 and ZEB1 expression was tested by immunofluorescence in cells and tumor samples. Parental and docetaxel-resistant castration-resistant prostate cancer cell lines were tested for epithelial-to-mesenchymal transition (EMT) markers before and after docetaxel exposure. Reversion of EMT phenotype was investigated as a docetaxel resistance reversion strategy. Expression of 63 (67.7%) genes differed between groups (P < 0.05), including genes related to androgen receptor, NF-k B transcription factor, and EMT. Increased expression of EMT markers correlated with radiologic relapse. Docetaxel-resistant cells had increased EMT and stem-like cell markers expression. ZEB1 siRNA transfection reverted docetaxel resistance and reduced CD44 expression in DU-145R and PC-3R. Before docetaxel exposure, a selected CD44 þ subpopulation of PC-3 cells exhibited EMT phenotype and intrinsic docetaxel resistance; ZEB1/CD44 þ subpopulations were found in tumor cell lines and primary tumors; this correlated with aggressive clinical behavior. This study identifies genes potentially related to chemotherapy resistance and supports evi-dence of the EMT role in docetaxel resistance and adverse clinical behavior in early prostate cancer.
Resumo:
We analyze the failure process of a two-component system with widely different fracture strength in the framework of a fiber bundle model with localized load sharing. A fraction 0≤α≤1 of the bundle is strong and it is represented by unbreakable fibers, while fibers of the weak component have randomly distributed failure strength. Computer simulations revealed that there exists a critical composition αc which separates two qualitatively different behaviors: Below the critical point, the failure of the bundle is brittle, characterized by an abrupt damage growth within the breakable part of the system. Above αc, however, the macroscopic response becomes ductile, providing stability during the entire breaking process. The transition occurs at an astonishingly low fraction of strong fibers which can have importance for applications. We show that in the ductile phase, the size distribution of breaking bursts has a power law functional form with an exponent μ=2 followed by an exponential cutoff. In the brittle phase, the power law also prevails but with a higher exponent μ=92. The transition between the two phases shows analogies to continuous phase transitions. Analyzing the microstructure of the damage, it was found that at the beginning of the fracture process cracks nucleate randomly, while later on growth and coalescence of cracks dominate, which give rise to power law distributed crack sizes.
Resumo:
Background: The G1-to-S transition of the cell cycle in the yeast Saccharomyces cerevisiae involves an extensive transcriptional program driven by transcription factors SBF (Swi4-Swi6) and MBF (Mbp1-Swi6). Activation of these factors ultimately depends on the G1 cyclin Cln3. Results: To determine the transcriptional targets of Cln3 and their dependence on SBF or MBF, we first have used DNA microarrays to interrogate gene expression upon Cln3 overexpression in synchronized cultures of strains lacking components of SBF and/or MBF. Secondly, we have integrated this expression dataset together with other heterogeneous data sources into a single probabilistic model based on Bayesian statistics. Our analysis has produced more than 200 transcription factor-target assignments, validated by ChIP assays and by functional enrichment. Our predictions show higher internal coherence and predictive power than previous classifications. Our results support a model whereby SBF and MBF may be differentially activated by Cln3. Conclusions: Integration of heterogeneous genome-wide datasets is key to building accurate transcriptional networks. By such integration, we provide here a reliable transcriptional network at the G1-to-S transition in the budding yeast cell cycle. Our results suggest that to improve the reliability of predictions we need to feed our models with more informative experimental data.
Resumo:
A role for the NADPH oxidases NOX1 and NOX2 in liver fibrosis has been proposed, but the implication of NOX4 is poorly understood yet. The aim of this work was to study the functional role of NOX4 in different cell populations implicated in liver fibrosis: hepatic stellate cells (HSC), myofibroblats (MFBs) and hepatocytes. Two different mice models that develop spontaneous fibrosis (Mdr2−/−/p19ARF−/−, Stat3Δhc/Mdr2−/−) and a model of experimental induced fibrosis (CCl4) were used. In addition, gene expression in biopsies from chronic hepatitis C virus (HCV) patients or non-fibrotic liver samples was analyzed. Results have indicated that NOX4 expression was increased in the livers of all animal models, concomitantly with fibrosis development and TGF-β pathway activation. In vitro TGF-β-treated HSC increased NOX4 expression correlating with transdifferentiation to MFBs. Knockdown experiments revealed that NOX4 downstream TGF-β is necessary for HSC activation as well as for the maintenance of the MFB phenotype. NOX4 was not necessary for TGF-β-induced epithelial-mesenchymal transition (EMT), but was required for TGF-β-induced apoptosis in hepatocytes. Finally, NOX4 expression was elevated in patients with hepatitis C virus (HCV)-derived fibrosis, increasing along the fibrosis degree. In summary, fibrosis progression both in vitro and in vivo (animal models and patients) is accompanied by increased NOX4 expression, which mediates acquisition and maintenance of the MFB phenotype, as well as TGF-β-induced death of hepatocytes.
Resumo:
La transición a la edad adulta y vida activa es un proceso extremadamente complejo para los jóvenes con discapacidad. Para plantear propuestas de actuación que mejoren sus oportunidades de conseguir objetivos relacionados con la inclusión laboral y social en la vida adulta es imprescindible el diagnóstico en profundidad del contexto en que se construyen y desarrollan los procesos de transición. En este artículo se presenta un estudio en el que se ha aplicado el método Delphi con el propósito de obtener datos sobre la adecuación de los servicios o dispositivos que trabajan con jóvenes con discapacidad a lo largo de su proceso de transición a la edad adulta y vida activa, tanto en el escenario escolar como en el postescolar. Se han constituido dos paneles de expertos, uno con profesionales del ámbito educativo y otro con profesionales que trabajan en servicios postescolares. En ambos casos, los ejes temáticos son: visión del proceso de transición, aspectos curriculares y organizativos de los servicios, existencia de itinerarios de apoyo sistematizados, trabajo colaborativo entre profesionales, acciones de orientación con familias, adecuación de las alternativas postescolares, la formación de los profesionales, y coordinación de servicios. El análisis de los cuestionarios permite constatar las principales dificultades percibidas por los expertos en cada uno de los ámbitos y establece líneas básicas de actuación para mejorar los procesos de tránsito, entre las cuales destaca la necesidad de reforzar el papel de los equipos multiprofesionales en la articulación de redes de trabajo interprofesional
Resumo:
Recently, the surprising result that ab initio calculations on benzene and other planar arenes at correlated MP2, MP3, configuration interaction with singles and doubles (CISD), and coupled cluster with singles and doubles levels of theory using standard Pople’s basis sets yield nonplanar minima has been reported. The planar optimized structures turn out to be transition states presenting one or more large imaginary frequencies, whereas single-determinant-based methods lead to the expected planar minima and no imaginary frequencies. It has been suggested that such anomalous behavior can be originated by two-electron basis set incompleteness error. In this work, we show that the reported pitfalls can be interpreted in terms of intramolecular basis set superposition error (BSSE) effects, mostly between the C–H moieties constituting the arenes. We have carried out counterpoise-corrected optimizations and frequency calculations at the Hartree–Fock, B3LYP, MP2, and CISD levels of theory with several basis sets for a number of arenes. In all cases, correcting for intramolecular BSSE fixes the anomalous behavior of the correlated methods, whereas no significant differences are observed in the single-determinant case. Consequently, all systems studied are planar at all levels of theory. The effect of different intramolecular fragment definitions and the particular case of charged species, namely, cyclopentadienyl and indenyl anions, respectively, are also discussed
Resumo:
The incorporation of the Spanish university system into the European Higher Education Areahas brought about a series of adaptations. Among the recommendations is the inclusion ofan external training period in a company, which has resulted in significant changes in thedegree syllabus in order to balance the theoretical and practical education required by thestudents. This new framework has been legally confirmed by the Spanish Government and, inthe case of the University of Barcelona, by the publication of internal guidelines. Takingadvantage of this new opportunity to adapt the Pharmacy degree to real-world problems inindustry, the Dean’s team of the Faculty of Pharmacy, with the support of the Facultyadministrative staff and the Students Advisory Service, have assumed the challenge ofincluding a new subject in the syllabus entitled Training in Companies.In parallel, a new activity has been set up to ensure that the students choose the mostsuitable company department/job for them and to help them pass the company interview.Under the name of Passport to a Profession, a series of ten explanatory talks has beenscheduled every academic year. These talks deal with a broad range of topics aimed atproviding the students with the basic tools they will need to make the most of a companytraining period and to make headway in the professional world when they finish theirdegree. In addition, three Faculty of Pharmacy-Pharmaceutical company workshops and tworound-table conferences have been held in the last two years in order to bring the universityand industry together. Notably, the project to provide students with company training isexpanding on an international level, with two to three undergraduate students contractedevery year by a United Kingdom-based multinational pharmaceutical company.The statistical data of the whole process has been analysed for a more in-depthunderstanding of the activity and to improve the programme.
Resumo:
This study examines the evolution of labor productivity across Spanish regions during the period from 1977 to 2002. By applying the kernel technique, we estimate the effects of the Transition process on labor productivity and its main sources. We find that Spanish regions experienced a major convergence process in labor productivity and in human capital in the 1977-1993 period. We also pinpoint the existence of a transition co-movement between labor productivity and human capital. Conversely, the dynamics of investment in physical capital seem unrelated to the transition dynamics of labor productivity. The lack of co-evolution can be addressed as one of the causes of the current slowdown in productivity. Classification-JEL: J24, N34, N940, O18, O52, R10
Resumo:
Las categorías del espacio introvertido y extrovertido definen por excelencia la estructura espacial, que ordena el ámbito de lo privado y lo público en la ciudad. La dualidad del espacio abierto y cerrado, vinculado a la estructura espacial de la ciudad clásica China, quedaba ordenado, justificado y vinculado mediante una estructura espacial muy definida. Sin embargo en el modelo de ciudad contemporánea, aflora la cuestión de la integración de estas categorías espaciales y su articulación dentro de una estructura urbana heterogénea y fuertemente alterada. ¿Cuáles serán los factores de cambio de la transición de un espacio comunitario introvertido a un espacio cívico abierto? Este proceso es un proceso que debe discurrir a un doble nivel espacial y político. Debe discurrir en paralelo a la transición de las categorías espaciales que ordenan identitariamente el ámbito urbano y la progresiva transición socio-cultural y política de una sociedad que debe gradualmente identificar y adoptar como propias las instituciones de gobierno local y su escenario, la ciudad.
Resumo:
This study engages with the debate over the mortality crises in the former Soviet Union and Central and Eastern Europe by 1) considering at length and as complementary to each other the two most prominent explanations for the post-communist mortality crisis, stress and alcohol consumption; 2) emphasizing the importance of context by exploiting systematic similarities and differences across the region. Differential mortality trajectories reveal three country groups that cluster both spatially and in terms of economic transition experiences. The first group are the countries furthest west in which mortality rates increased minimally after the transition began. The second group experienced a severe increase in mortality rates in the early 1990s, but recovered previous levels within a few years. These countries are located peripherally to Russia and its nearest neighbours. The final group consists of countries that experienced two mortality increases or in which mortality levels had not recovered to pre-transition levels well into the 21st century. Cross-sectional time-series data analyses of men’s and women’s age and cause-specific death rates reveal that the clustering of these countries and their mortality trajectories can be partially explained by the economic context, which is argued to be linked to stress and alcohol consumption. Above and beyond many basic differences in the country groups that are held constant—including geographically and historically shared cultural, lifestyle and social characteristics—poor economic conditions account for a remarkably consistent share of excess age-specific and cause-specific deaths.
Resumo:
In this paper we analyze the sensitivity of the labour market decisions of workers close toretirement with respect to the incentives created by public regulations. We improve upon the extensiveprior literature on the effect of pension incentives on retirement in two ways. First, bymodeling the transitions between employment, unemployment and retirement in a simultaneousmanner, paying special attention to the transition from unemployment to retirement (which is particularlyimportant in Spain). Second, by considering the influence of unobserved heterogeneity inthe estimation of the effect of our (carefully constructed) incentive variables.Using administrative data, we find that, when properly defined, economic incentives have astrong impact on labour market decisions in Spain. Unemployment regulations are shown to be particularlyinfluential for retirement behaviour, along with the more traditional determinants linked tothe pension system. Pension variables also have a major bearing on both workers reemploymentdecisions and on the strategic actions of employers. The quantitative impact of the incentives, however,is greatly affected by the existence of unobserved heterogeneity among workers. Its omissionleads to sizable biases in the assessment of the sensitivity to economic incentives, a finding thathas clear consequences for the credibility of any model-based policy analysis. We confirm theimportance of this potential problem in one especially interesting instance: the reform of earlyretirement provisions undertaken in Spain in 2002. We use a difference-in-difference approach tomeasure the behavioural reaction to this change, finding a large overestimation when unobservedheterogeneity is not taken into account.
Resumo:
The Pyrenees are an alpine chain with hercynian basement rocks that outcrop in a large area called the Axial Zone. These rocks have been involved in the alpine deformation events although their main structural features resulted from the Hercynian orogeny. A relevant characteristic of the Hercynian basement is a change in structural style in depth which has been commonly studied and interpreted in the Pallaresa Anticlinorium, in the Central Pyrenees. This anticlinorium is a complex hercynian structural unit whose southern part belongs to the suprastructure whereas the northern part corresponds mostly to a transition zone between the infrastructure and the suprastructure. Rocks of the suprastructure show a steeply dipping slaty cleavage as the dominant structure, which is overprinting folds and thrusts rarely going with pervasive deformation. The transition zone results from a slaty cleavage, very often close to the bedding, overprinted by one or two steep crenulation cleavages. A gradual boundary exists between both structural levels and it can be observed that the deformation developing slaty cleavage in the suprastructure grades to a crenulation foliation in the transition zone. The gradual character of that boundary, as seen in the northern end of the transition zone, suggests that the southern sharp boundary is not original. That boundary is interpreted as a northward dipping inverse fault, possibly with Alpine age. That fault causes a relative uplift of the rocks of the transition zone and gives this sharp boundary with the suprastructural levels. It provokes the asymmetry in the Pallaresa anticlinorium
Resumo:
We present structural and electrical properties for p- and n-type layers grown close to the transition between a-Si:H and nc-Si:H onto different substrates: Corning 1737 glass, ZnO:Al-coated glass and stainless steel. Structural properties were observed to depend on the substrate properties for samples grown under the same deposition conditions. Different behaviour was observed for n- and p-type material. Stainless steel seemed to enhance crystallinity when dealing with n-type layers, whereas an increased crystalline fraction was obtained on glass for p-type samples. Electrical conduction in the direction perpendicular to the substrate seemed to be mainly determined by the interfaces or by the existence of an amorphous incubation layer that might determine the electrical behaviour. In the direction perpendicular to the substrate, n-type layers exhibited a lower resistance value than p-type ones, showing better contact properties between the layer and the substrate.
Resumo:
El presente trabajo pretende mostrar los resultados de un estudio cuya intención era identificar posibles variables que afectan a los procesos y estrategias de integración laboral de personas procedentes de otros países; las necesidades formativas en relación al colectivo de referencia y ampliar el conocimiento del fenómeno en aras de la intervención psicoeducativa y social. A partir de una metodología de investigación de orientación cualitativa se ha concluido que las diferencias en cuanto a las estrategias de integración y sus logros están más determinadas por los niveles de cualificación en el país de origen que por las propias diferencias culturales. The article shows the results of a study carried out by the authors to identify possible variables that affect the processes and strategies of occupational integration of people coming from other countries, to establish training needs in relation to the reference group and to extend the knowledge of the phenomenon for the sake of the educational and social intervention. Using a qualitative research methodology, it was concluded that the differences in integration strategies and their accomplishments are better explained by the levels of qualification attained in the country of origin than by cultural differences.