2,854 research outputs found

    Interrogating Gender Texts: A Critical Review of the Literature

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    This paper synthesizes the Canadian adult education literature related to gender and adult learning. By examining how it has been written about, what it focuses on, and what the gaps are, the authors identified current contributions in the Canadian literature

    Perivascular mast cells promote neointimal elastin deposit and suppress chronic vein graft restensosis in hyperlipidaemic mice : mast cells and vein graft remodelling

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    Aims: Mast cells are versatile innate immune cells and are reported to promote vascular inflammation and neointimal lesion formation, thereby contributing to the development of vascular stenosis and atherosclerosis. However, it is not clear whether mast cells also regulate vascular matrix remodelling in established neointima. This study addressed the hypothesis that perivascular mast cells regulate neointimal matrix remodelling using a mouse vein graft model. Methods: The impact of mast cells on neointimal remodelling was investigated using mast cell-deficient animals in both normolipidaemic (KitW-sh/W-sh) and hyperlipidaemic (apoE-/-KitW-sh/W-sh) conditions. The effect of perivascular mast cells on vascular matrix remodelling, including collagen and elastin deposition, was investigated using a local mast cell reconstitution method that selectively repopulated mast cells around the carotid artery (where the vein graft was inserted) in KitW-sh/W-sh mice. Results: In normolipidaemic vein grafts (KitW-sh/W-sh vs. the wild type control C57BL/6J), collagen synthesis was not affected by mast cell deficiency at 4 weeks. In contrast, neointimal elastin was reduced by 6.5-fold in mast cell-deficient KitW-sh/W-sh mice, which was prevented by perivascular mast cell reconstitution. Mast cell deficiency induced a similar reduction in neointimal elastin in hyperlipidaemic mice (apoE-/-KitW-sh/W-sh vs. apoE-/-), with a significant increase in cell proliferation and neointimal area at 4 week. Conclusion: Mast cells appear to promote elastin deposition in vein grafts and this may lead to further suppression of cell proliferation and neointimal thickening under hyperlipidaemic conditions

    Perivascular mast cells promote neointimal elastin deposition and suppress chronic vein graft restenosis in hyperlipidaemic mice.

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    Aims: Mast cells are versatile innate immune cells and are reported to promote vascular inflammation and neointimal lesion formation, thereby contributing to the development of vascular stenosis and atherosclerosis. However, it is not clear whether mast cells also regulate vascular matrix remodelling in established neointima. This study addressed the hypothesis that perivascular mast cells regulate neointimal matrix remodelling using a mouse vein graft model. Methods: The impact of mast cells on neointimal remodelling was investigated using mast cell-deficient animals in both normolipidaemic (KitW-sh/W-sh) and hyperlipidaemic (apoE-/-KitW-sh/W-sh) conditions. The effect of perivascular mast cells on vascular matrix remodelling, including collagen and elastin deposition, was investigated using a local mast cell reconstitution method that selectively repopulated mast cells around the carotid artery (where the vein graft was inserted) in KitW-sh/W-sh mice. Results: In normolipidaemic vein grafts (KitW-sh/W-sh vs. the wild type control C57BL/6J), collagen synthesis was not affected by mast cell deficiency at 4 weeks. In contrast, neointimal elastin was reduced by 6.5-fold in mast cell-deficient KitW-sh/W-sh mice, which was prevented by perivascular mast cell reconstitution. Mast cell deficiency induced a similar reduction in neointimal elastin in hyperlipidaemic mice (apoE-/-KitW-sh/W-sh vs. apoE-/-), with a significant increase in cell proliferation and neointimal area at 4 week. Conclusion: Mast cells appear to promote elastin deposition in vein grafts and this may lead to further suppression of cell proliferation and neointimal thickening under hyperlipidaemic conditions

    Node-Negative Non-small Cell Lung Cancer: Pathological Staging and Survival in 1765 Consecutive Cases

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    IntroductionThis study aimed to evaluate prognostic factors in patients with node-negative non-small cell lung cancer and to assess revised International Association for the Study of Lung Cancer staging recommendations for this group.MethodsA retrospective analysis of 1765 consecutive pathologically node-negative patients treated by surgical resection between 1984 and 2007 was performed. Survival analysis was conducted using the Kaplan-Meier method. The independence of prognostic factors was analyzed using multivariate Cox proportional hazards modeling.ResultsThe median age of patients was 68 years, and the average length of follow-up was 6.3 years. Perioperative mortality was 1.7%. The median survival was 6.5 years, with a 56% of the cohort surviving 5 years. Factors associated with poorer prognosis were male gender (hazard ratio [HR]: 1.30, p = <0.001), age (HR: 1.04 per year of increase, p < 0.001), limited resection (HR: 1.30, p = 0.002) tumor size (HR: 1.10 per 10 mm increase, p < 0.001), large cell histopathological cell type (HR: 1.35, p < 0.001), and positive resection margins (HR: 1.58, p = 0.002). T stage was a superior predictor of survival than tumor size (p < 0.001). There was no difference in survival by T-stage descriptor within stage T2 or T3.ConclusionsIn surgically treated, node-negative non-small cell lung cancer, revised International Association for the Study of Lung Cancer staging criteria stratify survival well. Age, gender, and extent of resection are also important predictors of survival. Current T-stage descriptor groupings are appropriate

    Immunotherapy for Epstein-Barr Virus-Related Lymphomas

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    Latent EBV infection is associated with several malignancies, including EBV post-transplant lymphoproliferative disorders (LPD), Hodgkin and non-Hodgkin lymphomas, nasopharyngeal carcinoma and Burkitt lymphoma. The range of expression of latent EBV antigens varies in these tumors, which influences how susceptible the tumors are to immunotherapeutic approaches. Tumors expressing type III latency, such as in LPD, express the widest array of EBV antigens making them the most susceptible to immunotherapy. Treatment strategies for EBV-related tumors include restoring normal cellular immunity by adoptive immunotherapy with EBV-specific T cells and targeting the malignant B cells with monoclonal antibodies. We review the current immunotherapies and future studies aimed at targeting EBV antigen expression in these tumors

    Perivascular mast cells regulate vein graft neointimal formation and remodeling

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    Objective. Emerging evidence suggests an important role for mast cells in vein graft failure. This study addressed the hypothesis that perivascular mast cells regulate in situ vascular inflammatory and proliferative responses and subsequent vein graft neointimal lesion formation, using an optimized local mast cell reconstitution method. Methods and Results. Neointimal hyperplasia was induced by insertion of a vein graft into the right carotid artery in wild type and mast cell deficient KitW−sh/W−sh mice. In some experiments, mast cells were reconstituted systemically (tail vein injection of bone marrow-derived mast cells) or locally (directly into the right neck area) prior to vein grafting. Vein graft neointimal lesion formation was significantly (P &lt; 0.05) reduced in KitW−sh/W−sh mice. Mast cell deficiency reduced the number of proliferating cells, and inhibited L-selectin, CCL2, M-CSF and MIP-3α expression in the vein grafts. Local but not systemic mast cell reconstitution restored a perivascular mast cell population that subsequently promoted neointimal formation in mast cell deficient mice. Conclusion. Our data demonstrate that perivascular mast cells play a key role in promoting neointima formation by inducing local acute inflammatory and proliferative responses. These results suggest that ex vivo intraoperative targeting of mast cells may have therapeutic potential for the prevention of pathological vein graft remodeling

    Metal-Poor Stars Observed with the Magellan Telescope I. Constraints on Progenitor Mass and Metallicity of AGB Stars Undergoing s-Process Nucleosynthesis

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    We present a comprehensive abundance analysis of two newly-discovered carbon-enhanced metal-poor (CEMP) stars. HE2138-3336 is a s-process-rich star with [Fe/H] = -2.79, and has the highest [Pb/Fe] abundance ratio measured thus far, if NLTE corrections are included ([Pb/Fe] = +3.84). HE2258-6358, with [Fe/H] = -2.67, exhibits enrichments in both s- and r-process elements. These stars were selected from a sample of candidate metal-poor stars from the Hamburg/ESO objective-prism survey, and followed up with medium-resolution (R ~ 2,000) spectroscopy with GEMINI/GMOS. We report here on derived abundances (or limits) for a total of 34 elements in each star, based on high-resolution (R ~ 30,000) spectroscopy obtained with Magellan-Clay/MIKE. Our results are compared to predictions from new theoretical AGB nucleosynthesis models of 1.3 Mo with [Fe/H] = -2.5 and -2.8, as well as to a set of AGB models of 1.0 to 6.0 Mo at [Fe/H] = -2.3. The agreement with the model predictions suggests that the neutron-capture material in HE2138-3336 originated from mass transfer from a binary companion star that previously went through the AGB phase, whereas for HE2258-6358, an additional process has to be taken into account to explain its abundance pattern. We find that a narrow range of progenitor masses (1.0 < M(Mo) < 1.3) and metallicities (-2.8 < [Fe/H] < -2.5) yield the best agreement with our observed elemental abundance patterns.Comment: Accepted for publication in Ap

    Early-type stars observed in the ESO UVES Paranal Observatory Project - V. Time-variable interstellar absorption

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    The structure and properties of the diffuse interstellar medium (ISM) on small scales, sub-au to 1 pc, are poorly understood. We compare interstellar absorption-lines, observed towards a selection of O- and B-type stars at two or more epochs, to search for variations over time caused by the transverse motion of each star combined with changes in the structure in the foreground ISM. Two sets of data were used: 83 VLT- UVES spectra with approximately 6 yr between epochs and 21 McDonald observatory 2.7m telescope echelle spectra with 6 - 20 yr between epochs, over a range of scales from 0 - 360 au. The interstellar absorption-lines observed at the two epochs were subtracted and searched for any residuals due to changes in the foreground ISM. Of the 104 sightlines investigated with typically five or more components in Na I D, possible temporal variation was identified in five UVES spectra (six components), in Ca II, Ca I and/or Na I absorption-lines. The variations detected range from 7\% to a factor of 3.6 in column density. No variation was found in any other interstellar species. Most sightlines show no variation, with 3{\sigma} upper limits to changes of the order 0.1 - 0.3 dex in Ca II and Na I. These variations observed imply that fine-scale structure is present in the ISM, but at the resolution available in this study, is not very common at visible wavelengths. A determination of the electron densities and lower limits to the total number density of a sample of the sightlines implies that there is no striking difference between these parameters in sightlines with, and sightlines without, varying components.Comment: 19 pages, 11 figures, accepted for publication in MNRA
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