Logistic curve
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A set of 69 concentration-response curves from 5 acute ecotoxicity assays was fitted with a 2-parameter logistic equation. High correlation between values of regression parameters suggested similar slopes of the curves. This enabled derivation of the empirical single-parameter logistic equation with the sole median effective concentration (EC50) parameter. Such an equation might be useful in the evaluation of lower-quality (preliminary) experimental data and for the reduction of the number of test organisms and of testing costs.
- Klíčová slova
- Acute ecotoxicity assays, Concentration-response slope, EC50 calculation, Logistic model,
- MeSH
- Aliivibrio fischeri účinky léků MeSH
- Chlorophyta účinky léků MeSH
- Daphnia účinky léků MeSH
- dvojchroman draselný toxicita MeSH
- látky znečišťující životní prostředí toxicita MeSH
- logistické modely * MeSH
- referenční standardy MeSH
- testy akutní toxicity * normy MeSH
- živorodka MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- dvojchroman draselný MeSH
- látky znečišťující životní prostředí MeSH
Estrogenic compounds as well as other biologically active substances are commonly present in the form of complex mixtures in the environment. There is still no satisfactory model that would be capable of predicting the toxic effects of mixtures containing partial receptor agonists and compounds with different parameters of their dose-response curves. Therefore, a novel Full Logistic Model (FLM) of prediction using all the parameters of dose-response curves has been suggested and compared with previously published approaches. We tested the receptor-binding activities of selected estrogens including full and partial agonists and their mixtures using yeast reporter gene assays and the human T47D cell line. Combination effects were modeled with FLM and predicted curves were compared with the data obtained experimentally. FLM yielded a good fit to the experimental data from both the receptor-binding assays and gave better predictions than the previously published approaches. FLM also provided satisfactory results regarding final partial agonistic dose-response curves with maximum influenced by the inhibitory effect of the partial agonist. FLM is not limited by any simplification like the toxic equivalency factor approach or generalized concentration addition and therefore it could be employed for mixtures containing chemicals with different parameters of their dose-response curves (maximum, minimum, inflex point or slope).
- Klíčová slova
- Additive effect, Concentration addition, Endocrine disrupting compounds, Estrogen receptor, Logistic curve, T47D,
- MeSH
- benzhydrylové sloučeniny farmakologie MeSH
- biotest MeSH
- buněčné linie MeSH
- chemokin CXCL12 metabolismus MeSH
- estradiol farmakologie MeSH
- estrogeny farmakologie MeSH
- fenoly farmakologie MeSH
- lékové interakce MeSH
- lidé MeSH
- logistické modely * MeSH
- reportérové geny MeSH
- Saccharomyces cerevisiae genetika MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- benzhydrylové sloučeniny MeSH
- bisphenol A MeSH Prohlížeč
- chemokin CXCL12 MeSH
- CXCL12 protein, human MeSH Prohlížeč
- estradiol MeSH
- estrogeny MeSH
- fenoly MeSH
PURPOSE: Use of novel medical technologies, such as leadless pacemaker (LP) therapy, may be subjected to a learning curve effect. The objective of the current study was to assess the impact of operators' experience on the occurrence of serious adverse device effects (SADE) and procedural efficiency. METHODS: Patients implanted with a Nanostim LP (Abbott, USA) within two prospective studies (i.e., LEADLESS ll IDE and Leadless Observational Study) were assessed. Patients were categorized into quartiles based on operator experience. Learning curve analysis included the comparison of SADE rates at 30 days post-implant per quartile and between patients in quartile 4 (> 10 implants) and patients in quartiles 1 through 3 (1-10 implants). Procedural efficiency was assessed based on procedure duration and repositioning attempts. RESULTS: Nanostim LP implant was performed in 1439 patients by 171 implanters at 60 centers in 10 countries. A total of 91 (6.4%) patients experienced a SADE in the first 30 days. SADE rates dropped from 7.4 to 4.5% (p = 0.038) after more than 10 implants per operator. Total procedure duration decreased from 30.9 ± 19.1 min in quartile 1 to 21.6 ± 13.2 min (p < 0.001) in quartile 4. The need for multiple repositionings during the LP procedure reduced in quartile 4 (14.8%), compared to quartiles 1 (26.8%; p < 0.001), 2 (26.6%; p < 0.001), and 3 (20.4%; p = 0.03). CONCLUSIONS: Learning curves exist for Nanostim LP implantation. Procedure efficiency improved with increased operator experience, according to a decrease in the incidence of SADE, procedure duration, and repositioning attempts.
- Klíčová slova
- Arrhythmia, Leadless pacing, Learning curve, Pacemaker,
- MeSH
- časové faktory MeSH
- design vybavení * MeSH
- implantované elektrody MeSH
- internacionalita MeSH
- kardiostimulace umělá škodlivé účinky metody MeSH
- kardiostimulátor * MeSH
- křivka učení * MeSH
- lidé MeSH
- logistické modely MeSH
- monitorování fyziologických funkcí metody MeSH
- multivariační analýza MeSH
- plnění a analýza úkolů MeSH
- prognóza MeSH
- prospektivní studie MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- srdeční arytmie diagnostické zobrazování terapie MeSH
- srdeční elektrofyziologie výchova MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- multicentrická studie MeSH
- pozorovací studie MeSH
- srovnávací studie MeSH
Non-invasive breath analysis has been used to search for volatile biomarkers of lungs and airways infection by Pseudomonas aeruginosa, PA, in cystic fibrosis patients. The exhaled breath of 20 PA-infected patients and 38 PA-negative patients was analysed using selected ion flow tube mass spectrometry, SIFT-MS. Special attention was given to the positive identification and accurate quantification of 16 volatile compounds (VOCs) as assured by the detailed consideration of their analytical ion chemistry occurring in the SIFT-MS reactor. However, the diagnostic sensitivity and specificity of the concentrations of any of the 16 compounds taken individually were found to be low. But when a linear combination of the concentrations of all 16 VOCs was used to construct an optimised receiver operating characteristics (ROC) curve using a linear logistic model, the diagnostic separation of PA-infected patients relative to the PA-negative patients was apparently good in terms of the derived sensitivity (89%), specificity (86%), and the area under the ROC curve is 0.91. Four compounds were revealed by the linear logistic model as significant, viz. malondialdehyde, isoprene, phenol and acetoin. The implications of these results to PA detection in the airways are assessed. Whilst such a metabolomics approach to optimise the ROC curve is widely used in breath analysis, it can lead to misleading indications. Therefore, we conclude that the results of the linear logistic model analyses are of limited immediate clinical value. The identified compounds should rather be considered as a stimulus for further independent studies involving larger patient cohorts.
- MeSH
- biologické markery analýza MeSH
- cystická fibróza mikrobiologie MeSH
- dechové testy metody MeSH
- dítě MeSH
- dospělí MeSH
- hmotnostní spektrometrie MeSH
- lidé MeSH
- logistické modely MeSH
- metabolom MeSH
- metabolomika MeSH
- mladiství MeSH
- mladý dospělý MeSH
- předškolní dítě MeSH
- pseudomonádové infekce diagnóza MeSH
- Pseudomonas aeruginosa fyziologie MeSH
- ROC křivka MeSH
- senzitivita a specificita MeSH
- těkavé organické sloučeniny analýza MeSH
- vydechnutí * MeSH
- Check Tag
- dítě MeSH
- dospělí MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- předškolní dítě MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- biologické markery MeSH
- těkavé organické sloučeniny MeSH
Living organisms interact with various chemical compounds via receptors, which is described by the receptor theory. The affinity of the biologically active compounds toward receptors and their ability to trigger a biological or toxic signal vary substantially. In this work, we describe a new insight into understanding of the mode of action of receptor partial agonists and the receptor theory using a Full Logistic Model (FLM) of mixture toxicology. We describe the hypothesis that the effect of a partial agonist can be mathematically described via separation of agonistic and antagonistic behavior of the partial agonist where the antagonistic effect is described as an action of the compound producing zero effect. In this way, a competitive antagonist can be considered as an agonist with zero effect. This idea is also placed into a context with classical concepts, e.g., Gaddum's equation. Using the assumption that competitive antagonists are agonists with no effect, equations describing the microscopic and macroscopic equilibrium constants have been derived. Accordingly, we show that the constants could be calculated from the measured partial agonistic dose-response curve. As a consequence, we provide a simple mathematical tool for comparison of dose-response curves of drugs according to their affinities and efficacies.
- Klíčová slova
- Drug potency, Efficacy, Equilibrium dissociation constant, Mixture toxicology, Partial agonist, Receptor theory,
- MeSH
- biologické modely * MeSH
- lékové interakce * MeSH
- logistické modely * MeSH
- receptory buněčného povrchu metabolismus MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- receptory buněčného povrchu MeSH
OBJECTIVE: The objective was to describe the methodology used to develop new response criteria for adult DM/PM and JDM. METHODS: Patient profiles from prospective natural history data and clinical trials were rated by myositis specialists to develop consensus gold-standard ratings of minimal, moderate and major improvement. Experts completed a survey regarding clinically meaningful improvement in the core set measures (CSM) and a conjoint-analysis survey (using 1000Minds software) to derive relative weights of CSM and candidate definitions. Six types of candidate definitions for response criteria were derived using survey results, logistic regression, conjoint analysis, application of conjoint-analysis weights to CSM and published definitions. Sensitivity, specificity and area under the curve were defined for candidate criteria using consensus patient profile data, and selected definitions were validated using clinical trial data. RESULTS: Myositis specialists defined the degree of clinically meaningful improvement in CSM for minimal, moderate and major improvement. The conjoint-analysis survey established the relative weights of CSM, with muscle strength and Physician Global Activity as most important. Many candidate definitions showed excellent sensitivity, specificity and area under the curve in the consensus profiles. Trial validation showed that a number of candidate criteria differentiated between treatment groups. Top candidate criteria definitions were presented at the consensus conference. CONCLUSION: Consensus methodology, with definitions tested on patient profiles and validated using clinical trials, led to 18 definitions for adult PM/DM and 14 for JDM as excellent candidates for consideration in the final consensus on new response criteria for myositis.
- Klíčová slova
- 1000Minds software, conjoint analysis, dermatomyositis, hybrid measure, juvenile dermatomyositis, outcome assessment, polymyositis, response criteria,
- MeSH
- dermatomyozitida terapie MeSH
- lidé MeSH
- logistické modely MeSH
- minimální klinicky významný rozdíl MeSH
- plocha pod křivkou MeSH
- polymyozitida terapie MeSH
- výsledek terapie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- konsensus - konference MeSH
Hemodynamically unstable patients with severe hypothermia and preserved circulation should be transported to dedicated extracorporeal life support (ECLS) centers, but not all are eligible for extracorporeal therapy. In this group of patients, the outcome of rewarming may sometimes be unfavorable. It is, therefore, crucial to identify potential risk factors for death. Furthermore, it is unclear what criterion for hemodynamic stability should be adopted for patients with severe hypothermia. The aim of this study is to identify pre-rewarming predictors of death and their threshold values in hypothermic patients with core temperature ≤ 28 °C and preserved circulation, who were treated without extracorporeal rewarming. We conducted a multicenter retrospective study involving patients in accidental hypothermia with core temperature 28 °C or lower, and preserved spontaneous circulation on rewarming initiation. The data were collected from the International Hypothermia Registry, HELP Registry, and additional hospital data. The primary outcome was survival to hospital discharge. We conducted a multivariable logistic regression and receiver operating characteristic curve (ROC) analysis. In the multivariate analysis of laboratory tests and vital signs, systolic blood pressure (SBP) adjusted for cooling circumstances and base excess (BE) were identified as the best predictor of death (OR 0.974 95% CI 0.952-0.996), AUC ROC 0.79 (0.70-0.88). The clinically relevant cutoff for SBP was identified at 90 mmHg with a sensitivity of 0.74 (0.54-0.89) and a specificity of 0.70 (0.60-0.79). The increased risk of death among hypothermic patients with preserved circulation occurs among those with an SBP below 90 mmHg and in those who developed hypothermia in their homes.
- Klíčová slova
- Death, Emergency medicine, Hypotension, Hypothermia, Rewarming, Risk factors,
- MeSH
- dospělí MeSH
- hypotermie * mortalita terapie MeSH
- lidé středního věku MeSH
- lidé MeSH
- logistické modely MeSH
- prognóza MeSH
- retrospektivní studie MeSH
- rizikové faktory MeSH
- ROC křivka MeSH
- senioři MeSH
- terapeutické zahřívání metody MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- multicentrická studie MeSH
BACKGROUND: Accurate methods to preoperatively characterize adnexal tumors are pivotal for optimal patient management. A recent metaanalysis concluded that the International Ovarian Tumor Analysis algorithms such as the Simple Rules are the best approaches to preoperatively classify adnexal masses as benign or malignant. OBJECTIVE: We sought to develop and validate a model to predict the risk of malignancy in adnexal masses using the ultrasound features in the Simple Rules. STUDY DESIGN: This was an international cross-sectional cohort study involving 22 oncology centers, referral centers for ultrasonography, and general hospitals. We included consecutive patients with an adnexal tumor who underwent a standardized transvaginal ultrasound examination and were selected for surgery. Data on 5020 patients were recorded in 3 phases from 2002 through 2012. The 5 Simple Rules features indicative of a benign tumor (B-features) and the 5 features indicative of malignancy (M-features) are based on the presence of ascites, tumor morphology, and degree of vascularity at ultrasonography. Gold standard was the histopathologic diagnosis of the adnexal mass (pathologist blinded to ultrasound findings). Logistic regression analysis was used to estimate the risk of malignancy based on the 10 ultrasound features and type of center. The diagnostic performance was evaluated by area under the receiver operating characteristic curve, sensitivity, specificity, positive likelihood ratio (LR+), negative likelihood ratio (LR-), positive predictive value (PPV), negative predictive value (NPV), and calibration curves. RESULTS: Data on 4848 patients were analyzed. The malignancy rate was 43% (1402/3263) in oncology centers and 17% (263/1585) in other centers. The area under the receiver operating characteristic curve on validation data was very similar in oncology centers (0.917; 95% confidence interval, 0.901-0.931) and other centers (0.916; 95% confidence interval, 0.873-0.945). Risk estimates showed good calibration. In all, 23% of patients in the validation data set had a very low estimated risk (<1%) and 48% had a high estimated risk (≥30%). For the 1% risk cutoff, sensitivity was 99.7%, specificity 33.7%, LR+ 1.5, LR- 0.010, PPV 44.8%, and NPV 98.9%. For the 30% risk cutoff, sensitivity was 89.0%, specificity 84.7%, LR+ 5.8, LR- 0.13, PPV 75.4%, and NPV 93.9%. CONCLUSION: Quantification of the risk of malignancy based on the Simple Rules has good diagnostic performance both in oncology centers and other centers. A simple classification based on these risk estimates may form the basis of a clinical management system. Patients with a high risk may benefit from surgery by a gynecological oncologist, while patients with a lower risk may be managed locally.
- Klíčová slova
- International Ovarian Tumor Analysis, Simple Rules, adnexa, color Doppler, diagnosis, diagnostic algorithm, logistic regression analysis, ovarian cancer, ovarian neoplasms, preoperative evaluation, risk assessment, ultrasonography,
- MeSH
- hodnocení rizik MeSH
- kohortové studie MeSH
- lidé MeSH
- logistické modely MeSH
- nemoci děložních adnex diagnostické zobrazování MeSH
- nemocnice MeSH
- onkologická péče - zařízení MeSH
- prediktivní hodnota testů MeSH
- průřezové studie MeSH
- ROC křivka MeSH
- senzitivita a specificita MeSH
- ultrasonografie dopplerovská barevná MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- multicentrická studie MeSH
- práce podpořená grantem MeSH
- validační studie MeSH
BACKGROUND AND AIMS: Endoscopic papillectomy (EP) is the standard treatment for noninvasive ampullary lesions (ALs), whereas advanced cases require surgery. Managing ALs is challenging and may lead to over- or undertreatment. We developed a score to identify the best candidates for endoscopic or surgical treatment. METHODS: We analyzed 447 patients who underwent EP. The cohort was randomly split into a training set (n = 325) and validation set (n = 122). Logistic regression identified predictors for incomplete resection (R1), which were incorporated into a 4-item score. Performance was assessed using the area under the receiver-operating characteristic curve (AUROC). RESULTS: Independent predictors for R1 included size ≥30 mm (S), high-grade dysplasia and/or invasive cancer (D), laterally spreading-lesion (L), and bile or pancreatic duct dilation (D), which we named the SDLD score. ALs with 0 to 1 points had the highest complete resection rates (training, 86.0%; validation, 88.5%), whereas ≥2 points significantly increased R1 rates (training, 52.0%; validation, 57.7%; P < .001). The AUROC was 0.792 (training) and 0.708 (validation). CONCLUSIONS: The SDLD score predicts R1 in EP and aids in treatment decisions.
- MeSH
- adenom * chirurgie patologie MeSH
- ampulla Vateri * chirurgie patologie MeSH
- cholangiopankreatografie endoskopická retrográdní MeSH
- lidé středního věku MeSH
- lidé MeSH
- logistické modely MeSH
- nádory ductus choledochus * chirurgie patologie MeSH
- retrospektivní studie MeSH
- ROC křivka MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- sfinkterotomie endoskopická * MeSH
- vývody pankreatu patologie MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- validační studie MeSH
The aim was to verify the applicability of Reitan and Wolfson's proposed neuropsychological screening battery for adults (2006, 2008) in the Czech population. The sample consisted of 70 participants aged 19-65 years, all of whom were examined using a screening method as well as the full Halstead-Reitan neuropsychological battery (HRNB). The correlation, logistic regression, ROC curve analysis, sensitivity and specificity, and positive and negative predictive values were all calculated. The Pearson correlation between the screening scale of neuropsychological deficit and the General Neuropsychological Deficit Scale (GNDS) from HRNB was 0.78 (p < .001). When optimal cut-off scores of 8 were utilized (in accordance with Horwitz, Lynch, McCaffrey, & Fisher in Screening for neuropsychological impairment using Reitan and Wolfsońs preliminary neuropsychological test battery. Archives of Clinical Neuropsychology, 23, 393-398, 2008, but different from Reitan, & Wolfson in The use of serial testing in evaluating the need for comprehensive neuropsychological testing of adults. Applied Neuropsychology, 15, 21-32, 2008), 78.6% of individuals were correctly classified having neuropsychological impairment or no impairment according to the GNDS. Our results confirm that this neuropsychological screening battery has good psychometric properties in the Czech population.
- Klíčová slova
- Halstead–Reitan neuropsychological test battery (HRNB), Neuropsychological impairment, Receiver-operating characteristic (ROC), Screening battery,
- MeSH
- dospělí MeSH
- kognitivní poruchy diagnóza MeSH
- lidé středního věku MeSH
- lidé MeSH
- logistické modely MeSH
- neuropsychologické testy * MeSH
- prediktivní hodnota testů * MeSH
- ROC křivka MeSH
- senioři MeSH
- senzitivita a specificita MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- validační studie MeSH
- Geografické názvy
- Česká republika MeSH