435 research outputs found

    Multi-wavelength study of the gravitational lens system RXS J1131-1231: III. Long slit spectroscopy: micro-lensing probes the QSO structure

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    (ABRIDGED) Aims: We discuss and characterize micro-lensing among the 3 brightest lensed images (A-B-C) of the gravitational lens system RXS J1131-1231 (a quadruply imaged AGN) by means of long slit optical and NIR spectroscopy. Qualitative constraints on the size of different emission regions are derived. Methods: We decompose the spectra into their individual emission components using a multi-component fitting approach. A complementary decomposition of the spectra enables us to isolate the macro-lensed fraction of the spectra independently of any spectral modelling. Results: -1. The data support micro-lensing de-amplification of images A and C. Not only is the continuum emission microlensed in those images but also a fraction of the Broad Line emitting Region (BLR).-2. Micro-lensing of a very broad component of MgII emission line suggests that the corresponding emission occurs in a region more compact than the other components of the emission line. -3. We find evidence that a large fraction of the FeII emission arises in the outer parts of the BLR. We also find very compact emitting region in the ranges 3080-3540 A and 4630-4800 A that is likely associated with FeII. -4. The OIII narrow emission line regions are partly spatially resolved. This enables us to put a lower limit of 110h^{-1} pc on their intrinsic size. -5. Analysis of MgII absorption found in the spectra indicates that the absorbing medium is intrinsic to the quasar, has a covering factor of 20%, and is constituted of small clouds homogeneously distributed in front of the continuum and BLRs. -6. Two neighbour galaxies are detected at redshifts z=0.10 and z=0.289. These galaxies are possible members of galaxy groups reported at those redshifts.Comment: Accepted by Astronomy and Astrophysics. Small modifications to match the final versio

    Acute surgical wound-dressing procedure: Description of the steps involved in the development and validation of an observational metric

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    The aim of this study was to develop an observational metric that could be used to assess the performance of a practitioner in completing an acute surgical wound-dressing procedure using aseptic non-touch technique (ANTT). A team of clinicians, academics, and researchers came together to develop an observational metric using an iterative six-stage process, culminating in a Delphi panel meeting. A scoping review of the literature provided a background empirical perspective relating to wound-dressing procedure performance. Video recordings of acute surgical wound-dressing procedures performed by nurses in clinical (n = 11) and simulated (n = 3) settings were viewed repeatedly and were iteratively deconstructed by the metric development group. This facilitated the identification of the discrete component steps, potential errors, and sentinel (serious) errors, which characterise a wound dressing procedure and formed part of the observational metric. The ANTT wound-dressing observational metric was stress tested for clarity, the ability to be scored, and interrater reliability, calculated during a further phase of video analysis. The metric was then subjected to a process of cyclical evaluation by a Delphi panel (n = 21) to obtain face and content validity of the metric. The Delphi panel deliberation verified the face and content validity of the metric. The final metric has three phases, 31 individual steps, 18 errors, and 27 sentinel errors. The metric is a tool that identifies the standard to be attained in the performance of acute surgical wound dressings. It can be used as both an adjunct to an educational programme and as a tool to assess a practitioner's performance of a wound-dressing procedure in both simulated and clinical practice contexts

    Glargine and degludec: solution behaviour of higher dose synthetic insulins

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    Single, double and triple doses of the synthetic insulins glargine and degludec currently used in patient therapy are characterised using macromolecular hydrodynamic techniques (dynamic light scattering and analytical ultracentrifugation) in an attempt to provide the basis for improved personalised insulin profiling in patients with diabetes. Using dynamic light scattering and sedimentation velocity in the analytical ultracentrifuge glargine was shown to be primarily dimeric under solvent conditions used in current formulations whereas degludec behaved as a dihexamer with evidence of further association of the hexamers (“multi-hexamerisation”). Further analysis by sedimentation equilibrium showed that degludec exhibited reversible interaction between mono- and-di-hexamer forms. Unlike glargine, degludec showed strong thermodynamic non-ideality, but this was suppressed by the addition of salt. With such large injectable doses of synthetic insulins remaining in the physiological system for extended periods of time, in some case 24–40 hours, double and triple dose insulins may impact adversely on personalised insulin profiling in patients with diabetes

    Chemical combination effects predict connectivity in biological systems

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    Efforts to construct therapeutically useful models of biological systems require large and diverse sets of data on functional connections between their components. Here we show that cellular responses to combinations of chemicals reveal how their biological targets are connected. Simulations of pathways with pairs of inhibitors at varying doses predict distinct response surface shapes that are reproduced in a yeast experiment, with further support from a larger screen using human tumour cells. The response morphology yields detailed connectivity constraints between nearby targets, and synergy profiles across many combinations show relatedness between targets in the whole network. Constraints from chemical combinations complement genetic studies, because they probe different cellular components and can be applied to disease models that are not amenable to mutagenesis. Chemical probes also offer increased flexibility, as they can be continuously dosed, temporally controlled, and readily combined. After extending this initial study to cover a wider range of combination effects and pathway topologies, chemical combinations may be used to refine network models or to identify novel targets. This response surface methodology may even apply to non-biological systems where responses to targeted perturbations can be measured

    Comparison of sapwood invasion by three Phytophthora spp.in different hosts

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    Many Phytophthora spp. have recently been isolated from native vegetation in Western Australia. As their pathogenicity is often unknown, it is not possible to provide advice to land managers on the impact of site infestation on native plants and how these infestations should be managed. We describe a rapid screening method based on sapwood invasion that has been used to compare the pathogenicity of Phytophthora arenaria, P. cinnamomi and P. multivora. Radial invasion into the xylem of six banksias and three eucalypts was assessed in an excised branch assay in summer and winter. Branches were wound inoculated and invasion was assessed by plating from a strip of tissue cut across the stem at the inoculation point and at 40 mm above and below. A symptomless infection had established in both the bark and sapwood within 6 days. P. arenaria was only isolated from the strip of tissue at the inoculation point. P. cinnamomi was isolated from the sapwood of Banksia attenuata, B. burdettii, B. menziesii and B. speciosa 40 mm above or below the inoculation point in some experiments. P. multivora was isolated from B. speciosa 40 mm below the inoculation point in one experiment. Hyphae of both species were seen in both ray parenchyma cells and xylem vessels. The invasiveness of the Phytophthora spp. was compared on the two groups of hosts using scores for sapwood invasion at the inoculation point. For banksias, P. cinnamomi and P. multivora had significantly higher invasion scores on banksias than P. arenaria but were not significantly different to one another. There was no significant difference between the three Phytophthora spp. on the eucalypt hosts. Assessing sapwood invasion provides a rapid, inexpensive and biologically meaningful way of screening the many Phytophthora spp. that have been isolated from native vegetation

    Allergen Uptake, Activation, and IL-23 Production by Pulmonary Myeloid DCs Drives Airway Hyperresponsiveness in Asthma-Susceptible Mice

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    Maladaptive, Th2-polarized inflammatory responses are integral to the pathogenesis of allergic asthma. As regulators of T cell activation, dendritic cells (DCs) are important mediators of allergic asthma, yet the precise signals which render endogenous DCs “pro-asthmatic”, and the extent to which these signals are regulated by the pulmonary environment and host genetics, remains unclear. Comparative phenotypic and functional analysis of pulmonary DC populations in mice susceptible (A/J), or resistant (C3H) to experimental asthma, revealed that susceptibility to airway hyperresponsiveness is associated with preferential myeloid DC (mDC) allergen uptake, and production of Th17-skewing cytokines (IL-6, IL-23), whereas resistance is associated with increased allergen uptake by plasmacytoid DCs. Surprisingly, adoptive transfer of syngeneic HDM-pulsed bone marrow derived mDCs (BMDCs) to the lungs of C3H mice markedly enhanced lung IL-17A production, and rendered them susceptible to allergen-driven airway hyperresponsiveness. Characterization of these BMDCs revealed levels of antigen uptake, and Th17 promoting cytokine production similar to that observed in pulmonary mDCs from susceptible A/J mice. Collectively these data demonstrate that the lung environment present in asthma-resistant mice promotes robust pDC allergen uptake, activation, and limits Th17-skewing cytokine production responsible for driving pathologic T cell responses central to the development of allergen-induced airway hyperresponsiveness

    Bacteria isolated from lung modulate asthma susceptibility in mice

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    Asthma is a chronic, non-curable, multifactorial disease with increasing incidence in industrial countries. This study evaluates the direct contribution of lung microbial components in allergic asthma in mice. Germ-Free and Specific-Pathogen-Free mice display similar susceptibilities to House Dust Mice-induced allergic asthma, indicating that the absence of bacteria confers no protection or increased risk to aeroallergens. In early life, allergic asthma changes the pattern of lung microbiota, and lung bacteria reciprocally modulate aeroallergen responsiveness. Primo-colonizing cultivable strains were screened for their immunoregulatory properties following their isolation from neonatal lungs. Intranasal inoculation of lung bacteria influenced the outcome of allergic asthma development: the strain CNCM I 4970 exacerbated some asthma features whereas the pro-Th1 strain CNCM I 4969 had protective effects. Thus, we confirm that appropriate bacterial lung stimuli during early life are critical for susceptibility to allergic asthma in young adults

    Mesenteric lymph node transcriptome profiles in BALB/c mice sensitized to three common food allergens

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    <p>Abstract</p> <p>Background</p> <p>Food allergy is a serious health concern among infants and young children. Although immunological mechanism of food allergy is well documented, the molecular mechanism(s) involved in food allergen sensitization have not been well characterized. Therefore, the present study analyzed the mesenteric lymph node (MLN) transcriptome profiles of BALB/c mice in response to three common food allergens.</p> <p>Results</p> <p>Microarray analysis identified a total of 1361, 533 and 488 differentially expressed genes in response to β-lactoglobulin (BLG) from cow's milk, ovalbumin (OVA) from hen's egg white and peanut agglutinin (PNA) sensitizations, respectively (p < 0.05). A total of 150 genes were commonly expressed in all antigen sensitized groups. The expression of seven representative genes from microarray experiment was validated by real-time RT-PCR. All allergens induced significant ear swelling and serum IgG1 concentrations, whereas IgE concentrations were increased in BLG- and PNA-treated mice (p < 0.05). Treatment with OVA and PNA significantly induced plasma histamine concentrations (p < 0.05). The PCA demonstrated the presence of allergen-specific IgE in the serum of previously sensitized and challenged mice.</p> <p>Conclusions</p> <p>Immunological profiles indicate that the allergen dosages used are sufficient to sensitize the BALB/c mice and to conduct transcriptome profiling. Microarray studies identified several differentially expressed genes in the sensitization phase of the food allergy. These findings will help to better understand the underlying molecular mechanism(s) of food allergen sensitizations and may be useful in identifying the potential biomarkers of food allergy.</p

    Elevation of IL-6 in the allergic asthmatic airway is independent of inflammation but associates with loss of central airway function

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    <p>Abstract</p> <p>Background</p> <p>Asthma is a chronic inflammatory disease of the airway that is characterized by a Th2-type of immune response with increasing evidence for involvement of Th17 cells. The role of IL-6 in promoting effector T cell subsets suggest that IL-6 may play a functional role in asthma. Classically IL-6 has been viewed as an inflammatory marker, along with TNFα and IL-1β, rather than as regulatory cytokine.</p> <p>Objective</p> <p>To investigate the potential relationship between IL-6 and other proinflammatory cytokines, Th2/Th17 cytokines and lung function in allergic asthma, and thus evaluate the potential role of IL-6 in this disease.</p> <p>Methods</p> <p>Cytokine levels in induced sputum and lung function were measured in 16 healthy control and 18 mild-moderate allergic asthmatic subjects.</p> <p>Results</p> <p>The levels of the proinflammatory biomarkers TNFα and IL-1β were not different between the control and asthmatic group. In contrast, IL-6 levels were specifically elevated in asthmatic subjects compared with healthy controls (p < 0.01). Hierarchical regression analysis in the total study cohort indicates that the relationship between asthma and lung function could be mediated by IL-6. Among Th2 cytokines only IL-13 (p < 0.05) was also elevated in the asthmatic group, and positively correlated with IL-6 levels (r<sub>S </sub>= 0.53, p < 0.05).</p> <p>Conclusions</p> <p>In mild-moderate asthma, IL-6 dissociates from other proinflammatory biomarkers, but correlates with IL-13 levels. Furthermore, IL-6 may contribute to impaired lung function in allergic asthma.</p
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