741 research outputs found

    Structure and Dynamics of the EGF Receptor as Revealed by Experiments and Simulations and Its Relevance to Non-Small Cell Lung Cancer

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    The epidermal growth factor receptor (EGFR) is historically the prototypical receptor tyrosine kinase, being the first cloned and the first where the importance of ligand-induced dimer activation was ascertained. However, many years of structure determination has shown that EGFR is not completely understood. One challenge is that the many structure fragments stored at the PDB only provide a partial view because full-length proteins are flexible entities and dynamics play a key role in their functionality. Another challenge is the shortage of high-resolution data on functionally important higher-order complexes. Still, the interest in the structure/function relationships of EGFR remains unabated because of the crucial role played by oncogenic EGFR mutants in driving non-small cell lung cancer (NSCLC). Despite targeted therapies against EGFR setting a milestone in the treatment of this disease, ubiquitous drug resistance inevitably emerges after one year or so of treatment. The magnitude of the challenge has inspired novel strategies. Among these, the combination of multi-disciplinary experiments and molecular dynamic (MD) simulations have been pivotal in revealing the basic nature of EGFR monomers, dimers and multimers, and the structure-function relationships that underpin the mechanisms by which EGFR dysregulation contributes to the onset of NSCLC and resistance to treatment

    Compositional Evolution of Individual CoNPs on Co/TiO2 during CO and Syngas Treatment Resolved through Soft XAS/X-PEEM

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    The nanoparticle (NP) redox state is an important parameter in the performance of cobalt-based Fischer-Tropsch synthesis (FTS) catalysts. Here, the compositional evolution of individual CoNPs (6-24 nm) in terms of the oxide vs metallic state was investigated in situ during CO/syngas treatment using spatially resolved X-ray absorption spectroscopy (XAS)/X-ray photoemission electron microscopy (X-PEEM). It was observed that in the presence of CO, smaller CoNPs (i.e., ≤12 nm in size) remained in the metallic state, whereas NPs ≥ 15 nm became partially oxidized, suggesting that the latter were more readily able to dissociate CO. In contrast, in the presence of syngas, the oxide content of NPs ≥ 15 nm reduced, while it increased in quantity in the smaller NPs; this reoxidation that occurs primarily at the surface proved to be temporary, reforming the reduced state during subsequent UHV annealing. O K-edge measurements revealed that a key parameter mitigating the redox behavior of the CoNPs were proximate oxygen vacancies (Ovac). These results demonstrate the differences in the reducibility and the reactivity of Co NP size on a Co/TiO2 catalyst and the effect Ovac have on these properties, therefore yielding a better understanding of the physicochemical properties of this popular choice of FTS catalysts

    Drug-resistant EGFR mutations promote lung cancer by stabilizing interfaces in ligand-free kinase-active EGFR oligomers

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    The Epidermal Growth Factor Receptor (EGFR) is frequently found to be mutated in non-small cell lung cancer. Oncogenic EGFR has been successfully targeted by tyrosine kinase inhibitors, but acquired drug resistance eventually overcomes the efficacy of these treatments. Attempts to surmount this therapeutic challenge are hindered by a poor understanding of how and why cancer mutations specifically amplify ligand-independent EGFR auto-phosphorylation signals to enhance cell survival and how this amplification is related to ligand-dependent cell proliferation. Here we show that drug-resistant EGFR mutations manipulate the assembly of ligand-free, kinase-active oligomers to promote and stabilize the assembly of oligomer-obligate active dimer sub-units and circumvent the need for ligand binding. We reveal the structure and assembly mechanisms of these ligand-free, kinase-active oligomers, uncovering oncogenic functions for hitherto orphan transmembrane and kinase interfaces, and for the ectodomain tethered conformation of EGFR. Importantly, we find that the active dimer sub-units within ligand-free oligomers are the high affinity binding sites competent to bind physiological ligand concentrations and thus drive tumor growth, revealing a link with tumor proliferation. Our findings provide a framework for future drug discovery directed at tackling oncogenic EGFR mutations by disabling oligomer-assembling interactions

    Satisfação materna com o cuidado da enfermeira materno-infantil em Campeche, México

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    OBJECTIVE: Evaluate and compare maternal-satisfaction (global and areas) with maternal-child nursing care (MSMINC) and to explore the relationship of MSMINC with wait time, length of visit, and maternal age and education. METHODS: Cross-sectional descriptive study comprising 213 mothers. Group 1 (n = 84), mothers of children agedEl objetivo de este estudio fue evaluar y comparar la satisfacción materna (global/áreas) con el cuidado de la enfermera materno infantil (MSMINC) y explorar la relación de MSMINC con el tiempo de espera, duración de la visita, edad y educación materna. Se trata de un estudio descriptivo transversal. Participaron 213 madres. Grupo 1, n = 84 madres de niñosOBJETIVO: Avaliar e comparar a satisfação materna (global e áreas) com o cuidado da enfermeira materno-infantil (SMAEMI) e explorar a relação da SMAEMI com o tempo de espera e duração da visita, idade e educação da mãe. MÉTODOS: ESTUdo descritivo-transversal com a participação de 213 mães. Grupo 1, n = 84 mães de criança

    Estimates of cancer burden in Italy

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    This paper presents updated estimates of the incidence, prevalence and mortality of stomach, colorectal, lung, breast, uterine cervix and prostate cancer and skin melanoma in the Italian population. In particular, point estimates for 2012 and time trends from 1970 to 2015 will be provided

    Therapeutic communication between health workers and patients concerning diabetes mellitus care

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    The objective of this cross-sectional study was to analyze therapeutic communication techniques used by health workers with patients under care for diabetes mellitus. Data were collected in 2010 in a public facility in the interior of Ceará, Brazil using video camera equipment and direct observation. Results showed that the most frequently used techniques within the "expression" group were: asking questions, voicing interest, and using descriptive phrases. The most frequently used technique within the "clarification" group was: asking the patient to specify the agent of action. Finally, in regard to the "validation" group, only the technique "summarizing content of the interaction" was employed. The conclusion is that despite the use of communication techniques on the part of professionals, there is still an alarming gap concerning communication skills. Such skills should be allied with technical expertise to enable the delivery of qualified care to individuals with diabetes mellitus.Este estudio transversal tuvo como objetivo analizar las técnicas de comunicación terapéutica entre profesionales y pacientes en la atención en diabetes mellitus. Los datos se recogieron en una institución pública de Ceará-Brasil, en 2010, con equipos de video y observación directa. Los resultados mostraron que las técnicas del grupo de expresión más utilizadas fueron: hacer preguntas, expresar interés y usar frases descriptivas. Con relación a las del grupo de clarificación sobresalió solicitar al paciente que necesite el agente de la acción. Con relación a las de validación, apenas se utilizó las de organizar el contenido de la interacción. Se concluye que a pesar del uso de técnicas de comunicación por los profesionales, aun es preocupante la laguna con relación a la habilidad en comunicación, que debe ser aliada a la capacidad técnica, para así propiciar el cuidado calificado a las personas con diabetes mellitus.Objetivou-se, por este estudo transversal, analisar as técnicas de comunicação terapêutica entre profissionais e pacientes na atenção em diabetes mellitus. Os dados foram coletados em uma instituição pública de um município no interior do Ceará, Brasil, em 2010, por meio de equipamentos de vídeo e observação direta. Os resultados mostraram que as técnicas do grupo de expressão mais utilizadas foram: fazer perguntas, verbalizar interesse e usar frases descritivas. Quanto às do grupo de clarificação, sobressaiu solicitar ao paciente que precise o agente da ação. Em relação às de validação, apenas foi utilizada a técnica de sumarizar o conteúdo da interação. Conclui-se que, apesar do emprego de técnicas comunicacionais pelos profissionais, ainda é preocupante a lacuna referente à habilidade em comunicação, a qual deve ser aliada à competência técnica, para assim propiciar o cuidado qualificado às pessoas com diabetes mellitus

    A Study of B0 -> J/psi K(*)0 pi+ pi- Decays with the Collider Detector at Fermilab

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    We report a study of the decays B0 -> J/psi K(*)0 pi+ pi-, which involve the creation of a u u-bar or d d-bar quark pair in addition to a b-bar -> c-bar(c s-bar) decay. The data sample consists of 110 1/pb of p p-bar collisions at sqrt{s} = 1.8 TeV collected by the CDF detector at the Fermilab Tevatron collider during 1992-1995. We measure the branching ratios to be BR(B0 -> J/psi K*0 pi+ pi-) = (8.0 +- 2.2 +- 1.5) * 10^{-4} and BR(B0 -> J/psi K0 pi+ pi-) = (1.1 +- 0.4 +- 0.2) * 10^{-3}. Contributions to these decays are seen from psi(2S) K(*)0, J/psi K0 rho0, J/psi K*+ pi-, and J/psi K1(1270)
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