679 research outputs found

    Estrogen activation of microglia underlies the sexually dimorphic differences in Nf1 optic glioma-induced retinal pathology

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    Children with neurofibromatosis type 1 (NF1) develop low-grade brain tumors throughout the optic pathway. Nearly 50% of children with optic pathway gliomas (OPGs) experience visual impairment, and few regain their vision after chemotherapy. Recent studies have revealed that girls with optic nerve gliomas are five times more likely to lose vision and require treatment than boys. To determine the mechanism underlying this sexually dimorphic difference in clinical outcome, we leveraged Nf1 optic glioma (Nf1-OPG) mice. We demonstrate that female Nf1-OPG mice exhibit greater retinal ganglion cell (RGC) loss and only females have retinal nerve fiber layer (RNFL) thinning, despite mice of both sexes harboring tumors of identical volumes and proliferation. Female gonadal sex hormones are responsible for this sexual dimorphism, as ovariectomy, but not castration, of Nf1-OPG mice normalizes RGC survival and RNFL thickness. In addition, female Nf1-OPG mice have threefold more microglia than their male counterparts, and minocycline inhibition of microglia corrects the retinal pathology. Moreover, pharmacologic inhibition of microglial estrogen receptor-β (ERβ) function corrects the retinal abnormalities in female Nf1-OPG mice. Collectively, these studies establish that female gonadal sex hormones underlie the sexual dimorphic differences in Nf1 optic glioma–induced retinal dysfunction by operating at the level of tumor-associated microglial activation

    Low pressure radiofrequency balloon angioplasty: Evaluation in porcine peripheral arteries

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    AbstractObjectives. The purpose of this study was to evaluate the efficacy of radiofrequency-powered thermal balloon angioplasty in an in vivo porcine model.Background. Various modes of thermal energy used adjunctively during balloon angioplasty have demonstrated the potential to enhance the results of acute lumen dilation.Methods. In normal pigs, 75 peripheral arteries were dilated with a newly designed, radiofrequency-powered, thermal angioplasty balloon. All inflations were performed at 2-atm pressure for 85 s. Dilations were performed either with (hot) or without (cold) the application of heat. Lumen dimensions and vessel morphology were assessed with intravascular ultrasonography. At the end of each study, dilated arterial segments were harvested for histologic examination.Results. Single cold balloon inflations resulted in a 12.7% increase in arterial cross-sectional area whereas single hot inflations resulted in a 22.9% increase (p < 0.03). Similarly, when multiple cold inflations were compared with multiple hot inflations, two, three and four sequential hot inflations resulted in a significantly greater increase in cross-sectional area than an equivalent number of cold inflations (p < 0.03).Histologic examination demonstrated a temperaturedependent effect on the depth of medial necrosis and extent of arterial wall thinning (p < 0.001) as well as evidence for uniform alteration of elastic tissue fibers at temperatures of ≥60 °C (p < 0.03).Conclusions. Low pressure radiofrequency thermal balloon angioplasty results in a greater increase in cross-sectional area in porcine peripheral arteries than does nonheated conventional balloon angioplasty. The pathologic basis for this enhanced dilation may be a temperature-dependent effect on medial necrosis, thinning of the arterial wall or alteration of vascular elastic fibers, alone or in combination

    The voxel-wise analysis of false negative fMRI activation in regions of provoked impaired cerebrovascular reactivity

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    Task-evoked Blood-oxygenation-level-dependent (BOLD-fMRI) signal activation is widely used to interrogate eloquence of brain areas. However, data interpretation can be improved, especially in regions with absent BOLD-fMRI signal activation. Absent BOLD-fMRI signal activation may actually represent false-negative activation due to impaired cerebrovascular reactivity (BOLD-CVR) of the vascular bed. The relationship between impaired BOLD-CVR and BOLD-fMRI signal activation may be better studied in healthy subjects where neurovascular coupling is known to be intact. Using a model-based prospective end-tidal carbon dioxide (CO2) targeting algorithm, we performed two controlled 3 tesla BOLD-CVR studies on 17 healthy subjects: 1: at the subjects' individual resting end-tidal CO2 baseline. 2: Around +6.0 mmHg CO2 above the subjects' individual resting baseline. Two BOLD-fMRI finger-tapping experiments were performed at similar normo- and hypercapnic levels. Relative BOLD fMRI signal activation and t-values were calculated for BOLD-CVR and BOLD-fMRI data. For each component of the cerebral motor-network (precentral gyrus, postcentral gyrus, supplementary motor area, cerebellum und fronto-operculum), the correlation between BOLD-CVR and BOLD-fMRI signal changes and t-values was investigated. Finally, a voxel-wise quantitative analysis of the impact of BOLD-CVR on BOLD-fMRI was performed. For the motor-network, the linear correlation coefficient between BOLD-CVR and BOLD-fMRI t-values were significant (p<0.01) and in the range 0.33-0.55, similar to the correlations between the CVR and fMRI Δ%signal (p<0.05; range 0.34-0.60). The linear relationship between CVR and fMRI is challenged by our voxel-wise analysis of Δ%signal and t-value change between normo- and hypercapnia. Our main finding is that BOLD fMRI signal activation maps are markedly dampened in the presence of impaired BOLD-CVR and highlights the importance of a complementary BOLD-CVR assessment in addition to a task-evoked BOLD fMRI to identify brain areas at risk for false-negative BOLD-fMRI signal activation

    The SAURON project. II. Sample and early results

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    Early results are reported from the SAURON survey of the kinematics and stellar populations of a representative sample of nearby E, S0 and Sa galaxies. The survey is aimed at determining the intrinsic shape of the galaxies, their orbital structure, the mass-to-light ratio as a function of radius, the age and metallicity of the stellar populations, and the frequency of kinematically decoupled cores and nuclear black holes. The construction of the representative sample is described, and its properties are illustrated. A comparison with long-slit spectroscopic data establishes that the SAURON measurements are comparable to, or better than, the highest-quality determinations. Comparisons are presented for NGC 3384 and NGC 4365 where stellar velocities and velocity dispersions are determined to a precision of 6 km/s, and the h3 and h4 parameters of the line-of-sight velocity distribution to a precision of better than 0.02. Extraction of accurate gas emission-line intensities, velocities and line widths from the datacubes is illustrated for NGC 5813. Comparisons with published line-strengths for NGC 3384 and NGC 5813 reveal uncertainties of < 0.1 A on the measurements of the Hbeta, Mgb and Fe5270 indices. Integral-field mapping uniquely connects measurements of the kinematics and stellar populations to the galaxy morphology. The maps presented here illustrate the rich stellar kinematics, gaseous kinematics, and line-strength distributions of early-type galaxies. The results include the discovery of a thin, edge-on, disk in NGC 3623, confirm the axisymmetric shape of the central region of M32, illustrate the LINER nucleus and surrounding counter-rotating star-forming ring in NGC 7742, and suggest a uniform stellar population in the decoupled core galaxy NGC 5813.Comment: 20 pages, 17 figures. To be published in MNRAS. Version with full resolution images available at http://www.strw.leidenuniv.nl/~dynamics/Instruments/Sauron/pub_list.htm

    Returns to physician human capital: Evidence from patients randomized to physician teams

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    Physicians play a major role in determining the cost and quality of healthcare, yet estimates of these effects can be confounded by patient sorting. This paper considers a natural experiment where nearly 30,000 patients were randomly assigned to clinical teams from one of two academic institutions. One institution is among the top medical schools in the U.S., while the other institution is ranked lower in the distribution. Patients treated by the two programs have similar observable characteristics and have access to a single set of facilities and ancillary staff. Those treated by physicians from the higher ranked institution have 10–25% less expensive stays than patients assigned to the lower ranked institution. Health outcomes are not related to the physician team assignment. Cost differences are most pronounced for serious conditions, and they largely stem from diagnostic-testing rates: the lower ranked program tends to order more tests and takes longer to order them

    Potential of yeasts as biocontrol agents of the phytopathogen causing cacao Witches' Broom Disease: Is microbial warfare a solution?

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    Plant diseases caused by fungal pathogens are responsible for major crop losses worldwide, with a significant socio-economic impact on the life of millions of people who depend on agriculture-exclusive economy. This is the case of the Witches' Broom Disease (WBD) affecting cacao plant and fruit in South and Central America. The severity and extent of this disease is prospected to impact the growing global chocolate market in a few decades. WBD is caused by the basidiomycete fungus Moniliophthora perniciosa. The methods used to contain the fungus mainly rely on chemical fungicides, such as copper-based compounds or azoles. Not only are these highly ineffective, but also their utilization is increasingly restricted by the cacao industry, in part because it promotes fungal resistance, in part related to consumers' health concerns and environmental awareness. Therefore, the disease is being currently tentatively controlled through phytosanitary pruning, although the full removal of infected plant material is impossible and the fungus maintains persistent inoculum in the soil, or using an endophytic fungal parasite of Moniliophthora perniciosa which production is not sustainable. The growth of Moniliophthora perniciosa was reported as being antagonized in vitro by some yeasts, which suggests that they could be used as biological control agents, suppressing the fungus multiplication and containing its spread. Concurrently, some yeast-based products are used in the protection of fruits from postharvest fungal spoilage, and the extension of diverse food products shelf-life. These successful applications suggest that yeasts can be regarded a serious alternative also in the pre-harvest management of WBD and other fungal plant diseases. Yeasts' GRAS (Generally Recognized as Safe) nature adds to their appropriateness for field application, not raising major ecological concerns as do the present more aggressive approaches. Importantly, mitigating WBD, in a sustainable manner, would predictably have a high socioeconomic impact, contributing to diminish poverty in the cacao-producing rural communities severely affected by the disease. This review discusses the importance/advantages and the challenges that such a strategy would have for WBD containment, and presents the available information on the molecular and cellular mechanisms underlying fungi antagonism by yeasts.This work was supported by the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) funded by national funds through the FCT I.P. and by the ERDF through the COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI), and the project EcoAgriFood (NORTE-01-0145-FEDER-000009), supported by the Norte Portugal Regional Operational Programme (NORTE 2020) under the PORTUGAL 2020 Partnership Agreement through the European Regional Development Fund (ERDF). PF is a Ph.D. student of the Doctoral Programme in Applied and Environmental Microbiology (DP_AEM) and FCT grantee PD/BD/113810/2015

    Globalisation, accounting and developing countries

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    Accounting is an instrument and an object in globalisation but its impact and manifestation is not uniform across Northern developed countries and Southern developing countries (DCs). This paper reviews contributions on globalisation and its influence on accounting in DCs, and identifies important research gaps. It examines the role of accounting in changing development policies, from state capitalism through neo-liberal market-based to good-governance policies. It then considers specific accounting issues, namely the diffusion of International Accounting Standards (now International Financial Reporting Standards) and how they promote global neo-liberalism; the development of the accounting profession in DCs in the face of competition from Northern global accounting firms and professional associations; accounting issues in state-owned organisations, and privatised and multinational corporations; government accounting reforms and the resurrection of the state in DCs; social and environmental accounting issues; and the rise of non-governmental organisations and their accounting and accountability. The discussion and conclusions reflect on achievements to date and important areas requiring further development

    Alloplastische Implantate in der Kopf- und Halschirurgie.

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    The pathophysiology of restricted repetitive behavior

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    Restricted, repetitive behaviors (RRBs) are heterogeneous ranging from stereotypic body movements to rituals to restricted interests. RRBs are most strongly associated with autism but occur in a number of other clinical disorders as well as in typical development. There does not seem to be a category of RRB that is unique or specific to autism and RRB does not seem to be robustly correlated with specific cognitive, sensory or motor abnormalities in autism. Despite its clinical significance, little is known about the pathophysiology of RRB. Both clinical and animal models studies link repetitive behaviors to genetic mutations and a number of specific genetic syndromes have RRBs as part of the clinical phenotype. Genetic risk factors may interact with experiential factors resulting in the extremes in repetitive behavior phenotypic expression that characterize autism. Few studies of individuals with autism have correlated MRI findings and RRBs and no attempt has been made to associate RRB and post-mortem tissue findings. Available clinical and animal models data indicate functional and structural alterations in cortical-basal ganglia circuitry in the expression of RRB, however. Our own studies point to reduced activity of the indirect basal ganglia pathway being associated with high levels of repetitive behavior in an animal model. These findings, if generalizable, suggest specific therapeutic targets. These, and perhaps other, perturbations to cortical basal ganglia circuitry are mediated by specific molecular mechanisms (e.g., altered gene expression) that result in long-term, experience-dependent neuroadaptations that initiate and maintain repetitive behavior. A great deal more research is needed to uncover such mechanisms. Work in areas such as substance abuse, OCD, Tourette syndrome, Parkinson’s disease, and dementias promise to provide findings critical for identifying neurobiological mechanisms relevant to RRB in autism. Moreover, basic research in areas such as birdsong, habit formation, and procedural learning may provide additional, much needed clues. Understanding the pathophysioloy of repetitive behavior will be critical to identifying novel therapeutic targets and strategies for individuals with autism

    Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

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    Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio
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