203 resultados para Independent mobility
Resumo:
Evasion of apoptosis contributes to both tumourigenesis and drug resistance in non-small cell lung carcinoma (NSCLC). The pro-apoptotic BCL-2 family proteins BAX and BAK are critical regulators of mitochondrial apoptosis. New strategies for targeting NSCLC in a mitochondria-independent manner should bypass this common mechanism of apoptosis block. BRCA1 mutation frequency in lung cancer is low; however, decreased BRCA1 mRNA and protein expression levels have been reported in a significant proportion of lung adenocarcinomas. BRCA1 mutation/deficiency confers a defect in homologous recombination DNA repair that has been exploited by synthetic lethality through inhibition of PARP (PARPi) in breast and ovarian cells; however, it is not known whether this same synthetic lethal mechanism exists in NSCLC cells. Additionally, it is unknown whether the mitochondrial apoptotic pathway is required for BRCA1/PARPi-mediated synthetic lethality. Here we demonstrate that silencing of BRCA1 expression by RNA interference sensitizes NSCLC cells to PARP inhibition. Importantly, this sensitivity was not attenuated in cells harbouring mitochondrial apoptosis block induced by co-depletion of BAX and BAK. Furthermore, we demonstrate that BRCA1 inhibition cannot override platinum resistance, which is often mediated by loss of mitochondrial apoptosis signalling, but can still sensitize to PARP inhibition. Finally we demonstrate the existence of a BRCA1-deficient subgroup (11-19%) of NSCLC patients by analysing BRCA1 protein levels using immunohistochemistry in two independent primary NSCLC cohorts. Taken together, the existence of BRCA1-immunodeficient NSCLC suggests that this molecular subgroup could be effectively targeted by PARP inhibitors in the clinic and that PARP inhibitors could be used for the treatment of BRCA1-immunodeficient, platinum-resistant tumours. Copyright (C) 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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We have investigated the ability of collagen to induce signalling and functional responses in suspensions of murine platelets deficient in the FcRgamma (Fc receptor gamma) chain, which lack the collagen receptor GPVI (glycoprotein VI). In the absence of the FcRgamma chain, collagen induced a unique pattern of tyrosine phosphorylation which was potentiated by the thromboxane analogue U46619. Immunoprecipitation studies indicated that neither collagen alone nor the combination of collagen plus U46619 induced phosphorylation of the GPVI-regulated proteins Syk and SLP76 (Src homology 2-containing leucocyte protein of 76 kDa). A low level of tyrosine phosphorylation of phospholipase Cgamma2 was observed, which was increased in the presence of U46619, although the degree of phosphorylation remained well below that observed in wild-type platelets (similar to 10%). By contrast, collagen-induced phosphorylation of the adapter ADAP (adhesion- and degranulation-promoting adapter protein) was substantially potentiated by U46619 to levels equivalent to those observed in wild-type platelets. Collagen plus U46619 also induced significant phosphorylation of FAK (focal adhesion kinase). The functional significance of collagen-induced non-GPVI signals was highlighted by the ability of U46619 and collagen to induce the secretion of ATP in FcRgamma chain-deficient platelets, even though neither agonist was effective alone. Protein tyrosine phosphorylation and the release of ATP were abolished by the anti(alpha2 integrin) antibodies Ha1/29 and HMalpha2, but not by blockade of alphaIIbbeta3. These results illustrate a novel mechanism of platelet activation by collagen which is independent of the GPVI-FcRgamma chain complex, and is facilitated by binding of collagen to integrin alpha2beta1.
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The paper analyses the work-related spatial mobility intentions of incapacity benefit (IB) claimants in Northern Ireland using a new survey dataset. Greater understanding of the prospective mobility of benefit claimants contributes to debates about employability, inclusion in the labour market and arguments about spatial mismatch. The analysis finds that IB claimants are not markedly less mobile than other population groups; that mobility is shaped by age, level of qualification, illness type, ability to drive and motivation; and that geography is important in several ways. The paper concludes by arguing that limited spatial mobility is a good indicator of disadvantage and that spatial mobility should be placed nearer the centre of the design and delivery of labour market policy
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Background: How migration evolved represents one of the most poignant questions in evolutionary biology. While studies on the evolution of migration in birds are well represented in the literature, migration in bats has received relatively little attention. Yet, more than 30 species of bats are known to migrate annually from breeding to non-breeding locations. Our study is the first to test hypotheses on the evolutionary history of migration in bats using a phylogenetic framework. Methods and Principal Findings: In addition to providing a review of bat migration in relation to existing hypotheses on the evolution of migration in birds, we use a previously published supertree to formulate and test hypotheses on the evolutionary history of migration in bats. Our results suggest that migration in bats has evolved independently in several lineages potentially as the need arises to track resources (food, roosting site) but not through a series of steps from short- to long-distance migrants, as has been suggested for birds. Moreover, our analyses do not indicate that migration is an ancestral state but has relatively recently evolved in bats. Our results also show that migration is significantly less likely to evolve in cave roosting bats than in tree roosting species. Conclusions and Significance: This is the first study to provide evidence that migration has evolved independently in bat lineages that are not closely related. If migration evolved as a need to track seasonal resources or seek adequate roosting sites, climate change may have a pivotal impact on bat migratory habits. Our study provides a strong framework for future research on the evolution of migration in chiropterans. © 2009 Bisson et al.
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Purpose: Current prognostic factors are poor at identifying patients at risk of disease recurrence after surgery for stage II colon cancer. Here we describe a DNA microarray-based prognostic assay using clinically relevant formalin-fixed paraffin-embedded (FFPE) samples. Patients and Methods: A gene signature was developed from a balanced set of 73 patients with recurrent disease (high risk) and 142 patients with no recurrence (low risk) within 5 years of surgery. Results: The 634-probe set signature identified high-risk patients with a hazard ratio (HR) of 2.62 (P <.001) during cross validation of the training set. In an independent validation set of 144 samples, the signature identified high-risk patients with an HR of 2.53 (P <.001) for recurrence and an HR of 2.21 (P = .0084) for cancer-related death. Additionally, the signature was shown to perform independently from known prognostic factors (P <.001). Conclusion: This gene signature represents a novel prognostic biomarker for patients with stage II colon cancer that can be applied to FFPE tumor samples. © 2011 by American Society of Clinical Oncology.
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The mobility of a one-dimensional damped Frenkel-Kontorova chain under a de driving force is studied numerically and analytically For the commensurate case, the particles in the chain me synchronized st high driving force. For the incommensurate chain, a single mode solution dominates st high mobility regime. We are able to calculate the mobilities for both the cases analytically, and a good agreement with numerical results is found. The mobility hysteresis for the incommensurate chain is explained by the existence of two branches of physical solutions, and transitions occur when one of them breaks up.
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We present SuperWASP observations of HAT-P-14b, a hot Jupiter discovered by Torres et al. The planet was found independently by the SuperWASP team and named WASP-27b after follow-up observations had secured the discovery, but prior to the publication by Torres et al. Our analysis of HAT-P-14/WASP-27 is in good agreement with the values found by Torres et al. and we provide additional evidence against astronomical false positives. Due to the brightness of the host star, V-mag = 10, HAT-P-14b is an attractive candidate for further characterization observations. The planet has a high impact parameter and the primary transit is close to grazing. This could readily reveal small deviations in the orbital parameters indicating the presence of a third body in the system, which may be causing the small but significant orbital eccentricity. Our results suggest that the planet may undergo a grazing secondary eclipse. However, even a non-detection would tightly constrain the system parameters.
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From WASP photometry and SOPHIE radial velocities we report the discovery of WASP-40b (HAT-P-27b), a 0.6 M planet that transits its 12th magnitude host star every 3.04 days. The host star is of late G-type or early K-type and likely has a metallicity greater than solar ([Fe/H]=0.14±0.11). The planet's mass and radius are typical of the known hot Jupiters, thus adding another system to the apparent pileup of transiting planets with periods near 3-4 days. Our parameters match those of the recent HATnet announcement of the same planet, thus giving confidence in the techniques used. We report a possible indication of stellar activity in the host star.
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We report the detection of WASP-35b, a planet transiting a metal-poor ([Fe/H] = -0.15) star in the Southern hemisphere, WASP-48b, an inflated planet which may have spun-up its slightly evolved host star of 1.75 R sun in the Northern hemisphere, and the independent discovery of HAT-P-30b/WASP-51b, a new planet in the Northern hemisphere. Using WASP, RISE, Faulkes Telescope South, and TRAPPIST photometry, with CORALIE, SOPHIE, and NOT spectroscopy, we determine that WASP-35b has a mass of 0.72 ± 0.06 MJ and radius of 1.32 ± 0.05RJ , and orbits with a period of 3.16 days, WASP-48b has a mass of 0.98 ± 0.09 MJ , radius of 1.67 ± 0.10 RJ , and orbits in 2.14 days, while HAT-P-30b/WASP-51b, with an orbital period of 2.81 days, is found to have a mass of 0.76 ± 0.05 MJ and radius of 1.42 ± 0.03 RJ , agreeing with values of 0.71 ± 0.03 MJ and 1.34 ± 0.07 RJ reported for HAT-P-30b.
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Accepted for publication - will appear in advance view JEL and hard copy publication in (2012) Vol 24(2).