369 research outputs found

    An algorithm for collapsing sign alternating sequences of real numbers

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    AbstractA table with two rows and n columns may be thought of as two vectors with n components. The distance between the two rows then corresponds to the norm of the difference between the rows. We examine the problem of how to collapse the adjacent columns of the table while keeping the norm of the difference as large as possible. First a stepwise algorithm is given which achieves this end with respect to the norm of the vector of differences. After proving the optimality of the stepwise solution we extend the result to the norm which arises from minimizing the number of persons misclassified. The same algorithm suffices

    Near infra-red photoimmunotherapy with anti-CEA-IR700 results in extensive tumor lysis and a significant decrease in tumor burden in orthotopic mouse models of pancreatic cancer.

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    Photoimmunotherapy (PIT) of cancer utilizes tumor-specific monoclonal antibodies conjugated to a photosensitizer phthalocyanine dye IR700 which becomes cytotoxic upon irradiation with near infrared light. In this study, we aimed to evaluate the efficacy of PIT on human pancreatic cancer cells in vitro and in vivo in an orthotopic nude mouse model. The binding capacity of anti-CEA antibody to BxPC-3 human pancreatic cancer cells was determined by FACS analysis. An in vitro cytotoxicity assay was used to determine cell death following treatment with PIT. For in vivo determination of PIT efficacy, nude mice were orthotopically implanted with BxPC-3 pancreatic tumors expressing green fluorescent protein (GFP). After tumor engraftment, the mice were divided into two groups: (1) treatment with anti-CEA-IR700 + 690 nm laser and (2) treatment with 690 nm laser only. Anti-CEA-IR700 (100 ÎŒg) was administered to group (1) via tail vein injection 24 hours prior to therapy. Tumors were then surgically exposed and treated with phototherapy at an intensity of 150 mW/cm2 for 30 minutes. Whole body imaging was done subsequently for 5 weeks using an OV-100 small animal imaging system. Anti-CEA-IR700 antibody bound to the BxPC3 cells to a high degree as shown by FACS analysis. Anti-CEA-IR700 caused extensive cancer cell killing after light activation compared to control cells in cytotoxicity assays. In the orthotopic models of pancreatic cancer, the anti-CEA-IR700 group had significantly smaller tumors than the control after 5 weeks (p<0.001). There was no significant difference in the body weights of mice in the anti-CEA-IR700 and control groups indicating that PIT was well tolerated by the mice

    Serum Biomarkers of Disease Activity in Longitudinal Assessment of Patients with ANCA-Associated Vasculitis

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    OBJECTIVE: Improved biomarkers of current disease activity and prediction of relapse are needed in antineutrophil cytoplasmic antibody–associated vasculitis (AAV). For clinical relevance, biomarkers must perform well longitudinally in patients on treatment and in patients with nonsevere flares. METHODS: Twenty‐two proteins were measured in 347 serum samples from 74 patients with AAV enrolled in a clinical trial. Samples were collected at Month 6 after remission induction, then every 3 months until Month 18, or at the time of flare. Associations of protein concentrations with concurrent disease activity and with future flare were analyzed using mixed‐effects models, Cox proportional hazards models, and conditional logistic regression. RESULTS: Forty‐two patients had flares during the 12‐month follow‐up period, and 32 remained in remission. Twenty‐two patients had severe flares. Six experimental markers (CXCL13, IL‐6, IL‐8, IL‐15, IL‐18BP, and matrix metalloproteinase‐3 [MMP‐3]) and ESR were associated with disease activity using all three methods (P < 0.05, with P < 0.01 in at least one method). A rise in IL‐8, IL‐15, or IL‐18BP was associated temporally with flare. Combining C‐reactive protein (CRP), IL‐18BP, neutrophil gelatinase‐associated lipocalin (NGAL), and sIL‐2Rα improved association with active AAV. CXCL13 and MMP‐3 were increased during treatment with prednisone, independent of disease activity. Marker concentrations during remission were not predictive of future flare. CONCLUSION: Serum biomarkers of inflammation and tissue damage and repair have been previously shown to be strongly associated with severe active AAV were less strongly associated with active AAV in a longitudinal study that included mild flares and varying treatment. Markers rising contemporaneously with flare or with an improved association in combination merit further study

    A SAS macro for a clustered logrank test

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    The clustered logrank test is a nonparametric method of significance testing for correlated survival data. Examples of its application include cluster randomized trials where groups of patients rather than individuals are randomized to either a treatment or control intervention. We describe a SAS macro that implements the 2-sample clustered logrank test for data where the entire cluster is randomized to the same treatment group. We discuss the theory and applications behind this test as well as details of the SAS code

    A comparison of statistical approaches for physician-randomized trials with survival outcomes

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    This study compares methods for analyzing correlated survival data from physician-randomized trials of health care quality improvement interventions. Several proposed methods adjust for correlated survival data however the most suitable method is unknown. Applying the characteristics of our study example, we performed three simulation studies to compare conditional, marginal, and non-parametric methods for analyzing clustered survival data. We simulated 1,000 datasets using a shared frailty model with (1) fixed cluster size, (2) variable cluster size, and (3) non-lognormal random effects. Methods of analyses included: the nonlinear mixed model (conditional), the marginal proportional hazards model with robust standard errors, the clustered logrank test, and the clustered permutation test (non-parametric). For each method considered we estimated Type I error, power, mean squared error, and the coverage probability of the treatment effect estimator. We observed underestimated Type I error for the clustered logrank test. The marginal proportional hazards method performed well even when model assumptions were violated. Nonlinear mixed models were only advantageous when the distribution was correctly specified

    Lacunarity, lexicography and beyond: integration of the introduction of a linguo-cultural concept and the development of L2 learners’ dictionary skills

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    The paper discusses the integration of presenting theoretical linguocultural knowledge and developing dictionary skills in advanced students of a foreign language. The proposed approach allows showing students the interdisciplinary character of various issues, one of which is cross-linguistic lacunarity. It is given as an example of a phenomenon, whose introduction can be combined with the development of students’ dictionary use abilities. Lacunarity consists in the lack of some source language elements in the target language. Two main kinds of lacunae are distinguished: linguistic and referential ones. The focal issue of the paper is how the information on the lacunary character of words can be presented to advanced students of English as a foreign language, in this paper Polish learners, so that they could consider the phenomenon in terms of bilingual lexicography: first, becoming aware of the specifics of their description; second, practising their dictionary skills by analysing entries for selected lacunary lexical and phraseological units; third, combining the information and skills in doing creative tasks, related to lacunarity and its bilingual lexicographic descriptions. Furthermore, additional activities are proposed for revising the acquired knowledge on lacunarity and advancing dictionary use. Offering students tasks, which require them to adopt a different perspective, aims to increase their involvement in the learning process and to foster their autonomy as learners. Encouraging learners to reflect on lacunae and their lexicographic description is expected to familiarize them with the phenomenon and simultaneously to develop their dictionary skills by doing especially designed [email protected] University of Bialystok101-11

    Apomorphine Titration With and Without Anti-emetic Pretreatment In Patients With Parkinson’s Disease Experiencing off Episodes: A Modified Delphi Panel

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    INTRODUCTION: In the United States (US), prophylactic treatment with the antiemetic trimethobenzamide has been used before initiating apomorphine therapy. However, US trimethobenzamide stores have been depleted, leaving uncertainty regarding whether antiemetic pretreatment is needed. METHODS: This modified Delphi panel aimed to inform circumstances when apomorphine is initiated without antiemetic pretreatment. During Round 1, a panel of 9 US movement disorder specialists rated the appropriateness of prescribing apomorphine therapy with and without antiemetic pretreatment across 192 patient scenarios and were able to review their scores in relation to other scores. During the Round 2, consensus was defined for each scenario as either strong (\u3e75 % agreement) or moderate (66 % agreement). RESULTS: There was strong consensus on 118 of 192 scenario\u27s (97 as appropriate and 21 as inappropriate), moderate consensus on 29 scenarios, some agreement on 32 scenarios, and lack of agreement on 13 scenarios. In the absence of an antiemetic, there was strong consensus that titration schedules should be flexible and based on dose response. However, the group only reached moderate consensus on the speed of titration, highlighting the need for more systematic information on this area. In the presence of an antiemetic, panelists considered usual initial dosing and flexible titration to be appropriate in most scenarios except for when the patient is already experiencing dopaminergic adverse events. CONCLUSIONS: Experts generally reached consensus that apomorphine can usually be prescribed without antiemetic pretreatment. Recommendations described here reflect the areas of greatest agreement among a panel of experts based on current available evidence

    A point-of-care clinical trial comparing insulin administered using a sliding scale versus a weight-based regimen

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    Background Clinical trials are widely considered the gold standard in comparative effectiveness research (CER) but the high cost and complexity of traditional trials and concerns about generalizability to broad patient populations and general clinical practice limit their appeal. Unsuccessful implementation of CER results limits the value of even the highest quality trials. Planning for a trial comparing two standard strategies of insulin administration for hospitalized patients led us to develop a new method for a clinical trial designed to be embedded directly into the clinical care setting thereby lowering the cost, increasing the pragmatic nature of the overall trial, strengthening implementation, and creating an integrated environment of research-based care
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