755 research outputs found

    Beyond Exploratory: A Tailored Framework for Assessing Rigor in Qualitative Health Services Research

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    Objective: To propose a framework for assessing the rigor of qualitative research that identifies and distinguishes between the diverse objectives of qualitative studies currently used in patient-centered outcomes and health services research (PCOR and HSR). Study Design: Narrative review of published literature discussing qualitative guidelines and standards in peer-reviewed journals and national funding organizations that support PCOR and HSR. Principal Findings: We identify and distinguish three objectives of current qualitative studies in PCOR and HSR: exploratory, descriptive, and comparative. For each objective, we propose methodological standards that can be used to assess and improve rigor across all study phases—from design to reporting. Similar to quantitative studies, we argue that standards for qualitative rigor differ, appropriately, for studies with different objectives and should be evaluated as such. Conclusions: Distinguishing between different objectives of qualitative HSR improves the ability to appreciate variation in qualitative studies as well as appropriately evaluate the rigor and success of studies in meeting their own objectives. Researchers, funders, and journal editors should consider how adopting the criteria for assessing qualitative rigor outlined here may advance the rigor and potential impact of qualitative research in patient-centered outcomes and health services research

    Kallikrein-1 blockade inhibits aortic expansion in a mouse model and reduces prostaglandin E2 secretion from human aortic aneurysm explants

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    Background: Abdominal aortic aneurysm (AAA) is an important cause of mortality in older adults. The kinin B2 receptor agonist, bradykinin, has been implicated in AAA pathogenesis through promoting inflammation. Bradykinin is generated from high- and low-molecular-weight kininogen by the serine protease kallikrein-1. The aims of this study were first to examine the effect of neutralizing kallikrein-1 on AAA development in a mouse model and second to test how blocking kallikrein-1 affected cyclooxygenase-2 and prostaglandin E2 in human AAA explants. Methods and Results: Neutralization of kallikrein-1 in apolipoprotein E-deficient (ApoE-/-) mice via administration of a blocking antibody inhibited suprarenal aorta expansion in response to angiotensin (Ang) II infusion. Kallikrein-1 neutralization decreased suprarenal aorta concentrations of bradykinin and prostaglandin E2 and reduced cyclooxygenase-2 activity. Kallikrein-1 neutralization also decreased protein kinase B and extracellular signal-regulated kinase 1/2 phosphorylation and reduced levels of active matrix metalloproteinase 2 and matrix metalloproteinase 9. Kallikrein-1 blocking antibody reduced levels of cyclooxygenase-2 and secretion of prostaglandin E2 and active matrix metalloproteinase 2 and matrix metalloproteinase 9 from human AAA explants and vascular smooth muscle cells exposed to activated neutrophils. Conclusions: These findings suggest that kallikrein-1 neutralization could be a treatment target for AAA

    Calibrationless Multi-coil Magnetic Resonance Imaging with Compressed Sensing

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    We present a method for combining the data retrieved by multiple coils of a Magnetic Resonance Imaging (MRI) system with the a priori assumption of compressed sensing to reconstruct a single image. The final image is the result of an optimization problem that only includes constraints based on fundamental physics (Maxwell's equations and the Biot-Savart law) and accepted phenomena (e.g. sparsity in the Wavelet domain). The problem is solved using an alternating minimization approach: two convex optimization problems are alternately solved, one with the Fast Iterative Shrinkage Threshold Algorithm (FISTA) and the other with the Primal-Dual Hybrid Gradient (PDHG) method. We show results on simulated data as well as data of the knee, brain, and ankle. In all cases studied, results from the new algorithm show higher quality and increased detail when compared to conventional reconstruction algorithms

    Incorporating Breast Cancer Recurrence Events Into Population-Based Cancer Registries Using Medical Claims: Cohort Study.

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    BACKGROUND: There is a need for automated approaches to incorporate information on cancer recurrence events into population-based cancer registries. OBJECTIVE: The aim of this study is to determine the accuracy of a novel data mining algorithm to extract information from linked registry and medical claims data on the occurrence and timing of second breast cancer events (SBCE). METHODS: We used supervised data from 3092 stage I and II breast cancer cases (with 394 recurrences), diagnosed between 1993 and 2006 inclusive, of patients at Kaiser Permanente Washington and cases in the Puget Sound Cancer Surveillance System. Our goal was to classify each month after primary treatment as pre- versus post-SBCE. The prediction feature set for a given month consisted of registry variables on disease and patient characteristics related to the primary breast cancer event, as well as features based on monthly counts of diagnosis and procedure codes for the current, prior, and future months. A month was classified as post-SBCE if the predicted probability exceeded a probability threshold (PT); the predicted time of the SBCE was taken to be the month of maximum increase in the predicted probability between adjacent months. RESULTS: The Kaplan-Meier net probability of SBCE was 0.25 at 14 years. The month-level receiver operating characteristic curve on test data (20% of the data set) had an area under the curve of 0.986. The person-level predictions (at a monthly PT of 0.5) had a sensitivity of 0.89, a specificity of 0.98, a positive predictive value of 0.85, and a negative predictive value of 0.98. The corresponding median difference between the observed and predicted months of recurrence was 0 and the mean difference was 0.04 months. CONCLUSIONS: Data mining of medical claims holds promise for the streamlining of cancer registry operations to feasibly collect information about second breast cancer events

    The lncRNA landscape of breast cancer reveals a role for DSCAM-AS1 in breast cancer progression.

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    Molecular classification of cancers into subtypes has resulted in an advance in our understanding of tumour biology and treatment response across multiple tumour types. However, to date, cancer profiling has largely focused on protein-coding genes, which comprise <1% of the genome. Here we leverage a compendium of 58,648 long noncoding RNAs (lncRNAs) to subtype 947 breast cancer samples. We show that lncRNA-based profiling categorizes breast tumours by their known molecular subtypes in breast cancer. We identify a cohort of breast cancer-associated and oestrogen-regulated lncRNAs, and investigate the role of the top prioritized oestrogen receptor (ER)-regulated lncRNA, DSCAM-AS1. We demonstrate that DSCAM-AS1 mediates tumour progression and tamoxifen resistance and identify hnRNPL as an interacting protein involved in the mechanism of DSCAM-AS1 action. By highlighting the role of DSCAM-AS1 in breast cancer biology and treatment resistance, this study provides insight into the potential clinical implications of lncRNAs in breast cancer
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