39 research outputs found

    Robust estimation of bacterial cell count from optical density

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    Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

    Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

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    IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

    Sunsetting Excessive Chest X-rays in an Intensive Care Unit: A Quality Improvement Project

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    In the cardiovascular service line at an academic medical center in the southeastern United States, obtaining daily chest x-rays still occurred despite evidence that it is unnecessary and possibly even harmful. This quality improvement project was implemented in a 24-bed Cardiovascular Intensive Care Unit and 20-bed acute care unit, together considered to be the cardiac service line. Using the implementation framework of the Model for Improvement and Plan/Do/Study/Act, a guideline that outlines appropriate times to obtain a chest x-ray based on the American College of Radiology’s appropriateness criteria was created. Daily chest x-rays were eliminated and replaced with an on-demand chest x-ray ordering protocol. The project was implemented for two months. The intervention started on May 1st, the first day of the month, and ended on June 30th, the last day of the month. Institutional Review Board approval was obtained. Descriptive data such as patient age, gender, predicted risk of mortality, predicted risk of prolonged ventilation, and predicted risk of a long length of stay was analyzed for descriptive data only. A Mann-Whitney Rank Sum test was used to evaluate the primary outcome of frequency of chest x-rays and the secondary outcomes of hospital length of stay (LOS), intensive care unit length of stay (ICU LOS), 30-day mortality, ventilator hours, and reintubation rates. There was a statistically significant decrease in frequency (p \u3c 0.001) of chest x-rays with an associated significant decrease in patient cost (p \u3c 0.001) and radiation exposure (p \u3c 0.001). There was no change in hospital LOS, ICU LOS, ventilator hours, reintubation rates, or mortality rate. Replacing daily chest x-rays with an on-demand ordering approach is effective and efficient. This will remain a permanent practice change in the cardiovascular service line and open up opportunities for other quality improvement projects

    Global Pharmaceutical Regulation and the Challenge of Integration for Developing States

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    This contains the original data extracted from the WTO Country Pharmaceutical Situation 2011 survey as well as the R scripts need to replicate that findings, tables and graphics published in the paper
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