1,146 research outputs found
A unifying view for performance measures in multi-class prediction
In the last few years, many different performance measures have been
introduced to overcome the weakness of the most natural metric, the Accuracy.
Among them, Matthews Correlation Coefficient has recently gained popularity
among researchers not only in machine learning but also in several application
fields such as bioinformatics. Nonetheless, further novel functions are being
proposed in literature. We show that Confusion Entropy, a recently introduced
classifier performance measure for multi-class problems, has a strong
(monotone) relation with the multi-class generalization of a classical metric,
the Matthews Correlation Coefficient. Computational evidence in support of the
claim is provided, together with an outline of the theoretical explanation
Diagnostic accuracy of myocardial perfusion imaging with czt technology. Systemic review and meta-analysis of comparison with invasive coronary angiography
OBJECTIVES:
This study sought to summarize the evidence on stress myocardial perfusion imaging (MPI) using cadmium-zinc-telluride (CZT) technology for the diagnosis of obstructive coronary artery disease (CAD). The CZT cameras are newly introduced, and comparative data with the conventional Anger technology (Anger-MPI) are lacking.
BACKGROUND:
The diagnostic accuracy of Anger-MPI for detection of angiographically significant CAD is well established; however, less evidence is available on the diagnostic accuracy of CZT-MPI.
METHODS:
Clinical studies comparing CZT-MPI and invasive coronary angiography were systematically searched and abstracted. Calculations of diagnostic accuracy, including sensitivity, specificity, likelihood ratios, and diagnostic odds ratio, were obtained with fixed and random effects, reporting point estimates and 95% confidence intervals.
RESULTS:
Based on our search, a total of 16 studies (N = 2,092) were included. The sensitivity of CZT-MPI was 0.84 (95% confidence interval [CI]: 0.78 to 0.89), whereas the specificity of 0.69 (95% CI: 0.62 to 0.76) was significantly reduced. The positive likelihood ratio was 2.73 (95% CI: 2.21 to 3.39), the negative likelihood ratio was 0.24 (95% CI: 0.17 to 0.31), and the diagnostic odds ratio was 11.93 (95% CI: 7.84 to 17.42). At subgroup and meta-regression analyses, the diagnostic accuracy between D-SPECT and Discovery cameras was similar (p = 0.711) and not impacted upon by smaller sample size studies (p = 0.573).
CONCLUSIONS:
CZT-MPI has satisfactory sensitivity for angiographically significant CAD, but its suboptimal specificity warrants further development and research
Serum and supplement optimization for EU GMP-compliance in cardiospheres cell culture
Cardiac progenitor cells (CPCs) isolated as cardiospheres (CSs) and CS-derived cells (CDCs) are a promising tool for cardiac cell therapy in heart failure patients, having CDCs already been used in a phase I/II clinical trial. Culture standardization according to Good Manufacturing Practices (GMPs) is a mandatory step for clinical translation. One of the main issues raised is the use of xenogenic additives (e.g. FBS, foetal bovine serum) in cell culture media, which carries the risk of contamination with infectious viral/prion agents, and the possible induction of immunizing effects in the final recipient. In this study, B27 supplement and sera requirements to comply with European GMPs were investigated in CSs and CDCs cultures, in terms of process yield/efficiency and final cell product gene expression levels, as well as phenotype. B27- free CS cultures produced a significantly reduced yield and a 10-fold drop in c-kit expression levels versus B27+ media. Moreover, autologous human serum (aHS) and two different commercially available GMP AB HSs were compared with standard research-grade FBS. CPCs from all HSs explants had reduced growth rate, assumed a senescent-like morphology with time in culture, and/or displayed a significant shift towards the endothelial phenotype. Among three different GMP gamma-irradiated FBSs (giFBSs) tested, two provided unsatisfactory cell yields, while one performed optimally, in terms of CPCs yield/phenotype. In conclusion, the use of HSs for the isolation and expansion of CSs/CDCs has to be excluded because of altered proliferation and/or commitment, while media supplemented with B27 and the selected giFBS allows successful EU GMP-complying CPCs culture
Impact of electronic alternatives to tobacco cigarettes on indoor air particular matter levels
An aerosol study was carried out in a test room measuring particulate matter (PM) with
an aerodynamic diameter smaller than 10, 4, 2.5 and 1 m (PM10, PM4, PM2.5, PM1) before and
during the use of electronic alternatives to tobacco cigarettes (EATC) IQOS®, GLO®, JUUL®, with
dierent kinds of sticks/pods, as well as during the smoking of a conventional tobacco cigarette.
The aerosol was mainly in the PM1 size range (>95%). All studied EATCs caused lower indoor PM1
concentrations than conventional tobacco cigarettes. Nevertheless, they determined a worsening of
indoor-PM1 concentration that ranged from very mild for JUUL®—depending on the pod used—to
considerably severe for IQOS® and GLO®. Median values ranged from 11.00 (Iqos3 and Juul2) to
337.5 g m3 (Iqos4). The high variability of particle loadings was attributed both to the type of
stick/pod used and to the dierent way of smoking of volunteers who smoked/vaped during the
experiments. Moreover, during vaping IQOS® and GLO® indoor PM1 concentrations reach levels
by far higher than outdoor concentrations that range from 14 to 21 g m3, especially during the
exhalation of the smoke. From these results emerge an urgent need of a legislative regulation limiting
the use of such devices in public places
from big data to bedside decision making the case for adverseevents
Evidence-based medicine has gained mainstream popularity, but it requires a delicate balance between clinical evidence, physician skills, patient preferences, and costs. Facing the individual patient, even a simple decision such as which antithrombotic agent should be prescribed becomes complex. There are several reasons for this conundrum, but one of the foremost is the limited external validity of pivotal randomized trials, with their extremely restrictive selection criteria. Post-marketing reporting of adverse events is a very useful and democratic means to appraise the risk-benefit profile, but to date such reports were not organized or available. The development of the Food and Drug Administration (FDA) venue for such task, the FDA Adverse Event Reporting System (FAERS) has substantially improved data collection. However, analysis of this extensive relational database remains complex for most but few companies or agencies. AdverseEvents is a novel online platform enabling updated and user-friendly inquiry of FAERS. Given its ease of use, flexibility and comprehensiveness, it is likely going to improve decision making for healthcare authorities and practitioners, as well as patients. This is clearly testified by the precise and informative comparative analysis that can be performed with AdverseEvents on novel antithrombotic agents.</p
Agreement between adjusted indirect comparison and simplified network meta-analyses on prasugrel and ticagrelor (Reply to Passaro et al. - Int J Cardiol 2011)
Comment on
Anti-platelet treatments in acute coronary syndrome: simplified network meta-analysis. [Int J Cardiol. 2011
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