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101.
Els Goetghebeur Saskia le Cessie Bianca De Stavola Erica EM Moodie Ingeborg Waernbaum “on behalf of” the topic group Causal Inference of the STRATOS initiative 《Statistics in medicine》2020,39(30):4922-4948
Although review papers on causal inference methods are now available, there is a lack of introductory overviews on what they can render and on the guiding criteria for choosing one particular method. This tutorial gives an overview in situations where an exposure of interest is set at a chosen baseline (“point exposure”) and the target outcome arises at a later time point. We first phrase relevant causal questions and make a case for being specific about the possible exposure levels involved and the populations for which the question is relevant. Using the potential outcomes framework, we describe principled definitions of causal effects and of estimation approaches classified according to whether they invoke the no unmeasured confounding assumption (including outcome regression and propensity score-based methods) or an instrumental variable with added assumptions. We mainly focus on continuous outcomes and causal average treatment effects. We discuss interpretation, challenges, and potential pitfalls and illustrate application using a “simulation learner,” that mimics the effect of various breastfeeding interventions on a child's later development. This involves a typical simulation component with generated exposure, covariate, and outcome data inspired by a randomized intervention study. The simulation learner further generates various (linked) exposure types with a set of possible values per observation unit, from which observed as well as potential outcome data are generated. It thus provides true values of several causal effects. R code for data generation and analysis is available on www.ofcaus.org , where SAS and Stata code for analysis is also provided. 相似文献
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Forty-five patients undergoing double-contrast barium enema examinations were studied to identify the incidence of transient bacteremia associated with the examination. Blood cultures were obtained immediately prior to the examination and at 5, 10, and 20 minutes after the start of the examination. Blood samples were cultured in both aerobic and anaerobic media, and four of these cultures were positive for organisms that are common skin contaminants. No bacteremia was identified from enteric pathogens. The data herein suggest that patients with cardiac valvular disease are not at greater risk of bacteremia during double-contrast barium enema examinations. 相似文献
104.
Histamine reduces boron neutron capture therapy‐induced mucositis in an oral precancer model 下载免费PDF全文
105.
BACKGROUND AND PURPOSE
Conditioned gaping reactions reflect nausea-induced behaviour in rats. Cannabinoid 1 receptor (CB1) agonists interfere with the establishment of nausea-induced conditioned gaping; however, it is not known if their effects are mediated by an action at peripheral or central CB1 receptors.EXPERIMENTAL APPROACH
We utilized the conditioned gaping model of nausea to evaluate the effect of peripheral and central administration of the peripherally restricted CB1 agonist, CB13, on the establishment of LiCl-induced gaping in rats. We further evaluated the ability of HU-210 administered to the gustatory insular cortex (GIC) or visceral insular cortex (VIC) to interfere with LiCl-induced conditioned gaping and determined if this effect was mediated by CB1 receptors.KEY RESULTS
Central, but not peripheral, CB13 suppressed LiCl-induced conditioned gaping. Central administration of the potent CB1 agonist, HU-210, delivered to the VIC, but not the GIC, suppressed the establishment of LiCl-induced gaping reactions, but not LiCl-induced suppression of hedonic reactions or conditioned taste avoidance. This pattern of results suggests that HU-210 delivered to the VIC prevented LiCl-induced nausea, but not learning per se. The suppression of LiCl-induced conditioned gaping by HU-210 was mediated by CB1 receptors because it was prevented by co-administration of CB1 antagonist/inverse agonist, AM-251, into the VIC. A high dose of AM-251 (20 µg) administered alone into the VIC did not produce conditioned gaping reactions.CONCLUSIONS AND IMPLICATIONS
The nausea-relieving effects of CB1 agonists, but not the nausea-inducing effects of CB1 inverse agonists, are mediated, at least in part, by their action at the VIC in rats. 相似文献106.
The aim of this study was to evaluate the effect of hormone replacement therapy (HRT) on the expression of Ki-67, bcl-2 and c-erb.B2 in endometrial polyps during menopause. Sixteen patients using HRT and 24 untreated controls with endometrial polyps were enrolled in this study. Polypectomy was carried out by hysteroscopy. The presence of c-erb.B2, bcl-2 and Ki-67 expression was determined by immunohistochemistry. HRT was found to decrease Ki-67 and bcl-2 expression in endometrial polyps without affecting the c-erb.B2 staining reaction. HRT may cause endometrial polyp involution by decreasing proliferation and stimulating apoptosis. 相似文献
107.
Sara Gray MD FRCPC MPH Bjug Borgundvaag MD PhD CCFP‐EM Anita Sirvastava MD CCFP MSc Ian Randall MD Meldon Kahan MD MHSc CCFP FRCPC FCFP 《Academic emergency medicine》2010,17(10):1048-1054
Background: Use of a symptom‐triggered scale to measure the severity of alcohol withdrawal could reduce the rate of seizures and other complications. The current standard scale, the Clinical Institute of Withdrawal Assessment (CIWA), takes a mean (±SD) of 5 minutes to complete, requiring 30 minutes of nursing time per patient when multiple measures are required. Objectives: The objective was to assess the feasibility and reliability of a brief scale of alcohol withdrawal severity. Methods: The SHOT is a brief scale designed to assess alcohol withdrawal in the emergency department (ED). It includes four items: sweating, hallucinations, orientation, and tremor (SHOT). It was developed based on a literature review and a consensus process by emergency and addiction physicians. The SHOT was first piloted in one ED, and then a prospective observational study was conducted at a different ED to measure its feasibility and reliability. Subjects included patients who were in alcohol withdrawal. One nurse administered the SHOT and CIWA, and the physician repeated the SHOT independently. The SHOT was done only at baseline, before treatment was administered. Results: In the pilot study (12 patients), the SHOT took 1 minute to complete on average, and the CIWA took 5 minutes. Sixty‐one patients participated in the prospective study. For the SHOT and the CIWA done by the same nurse, the kappa was 0.88 (95% confidence interval [CI] = 0.52 to 1.0; p < 0.0001), and the Pearson’s r was 0.71 (p < 0.001). The kappa for the nurse’s CIWA score and the physician’s SHOT score was 0.61 (95% CI = 0.25 to 0.97; p < 0.0006), and the Pearson’s r was 0.48 (p = 0.002). The SHOTs performed by the nurse and physician agreed on the need for benzodiazepine treatment in 30 of 37 cases (82% agreement, kappa = 0.35, 95% CI = 0.03 to 0.67; p < 0.02). The mean (±SD) time taken by nurses and physicians to complete the SHOT was 1 (± 0.52) minute (median = 0.6 minutes). Seventeen percent of patients scored positive on the SHOT for hallucinations or disorientation. Conclusions: The SHOT has potential as a feasible and acceptable tool for measuring pretreatment alcohol withdrawal severity in the ED. Further research is needed to validate the SHOT, to assess the utility of serial measurements of the SHOT, and to demonstrate that its use reduces length of stay and improves clinical outcomes. ACADEMIC EMERGENCY MEDICINE 2010; 17:1048–1054 © 2010 by the Society for Academic Emergency Medicine 相似文献
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Thirty-two patients treated on consecutive Southwest Oncology Group (SWOG) protocols for malignant lymphoma were subsequently diagnosed as having lymphoblastic lymphoma. Combination chemistry, usually adriamycin-based, produced complete responses (CR) in 17 patients (53%). Median survival was 15 mo. Patients achieving a CR survival significantly longer than patients with partial or no response (p < 0.01). Ten of 24 patients not receiving central nervous system (CNS) prophylaxis developed leptomeningeal lymphoma while none of the seven patients who received prophylactic intrathecal cytosine arabinoside or methotrexate developed CNS lymphoma (p = 0.04). Implications of these results for planning future treatment programs of lymphoblastic lymphoma are discussed. 相似文献
110.