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1.
Nature ; 601(7893): 415-421, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34987220

RESUMEN

Transcriptional and proteomic profiling of individual cells have revolutionized interpretation of biological phenomena by providing cellular landscapes of healthy and diseased tissues1,2. These approaches, however, do not describe dynamic scenarios in which cells continuously change their biochemical properties and downstream 'behavioural' outputs3-5. Here we used 4D live imaging to record tens to hundreds of morpho-kinetic parameters describing the dynamics of individual leukocytes at sites of active inflammation. By analysing more than 100,000 reconstructions of cell shapes and tracks over time, we obtained behavioural descriptors of individual cells and used these high-dimensional datasets to build behavioural landscapes. These landscapes recognized leukocyte identities in the inflamed skin and trachea, and uncovered a continuum of neutrophil states inside blood vessels, including a large, sessile state that was embraced by the underlying endothelium and associated with pathogenic inflammation. Behavioural screening in 24 mouse mutants identified the kinase Fgr as a driver of this pathogenic state, and interference with Fgr protected mice from inflammatory injury. Thus, behavioural landscapes report distinct properties of dynamic environments at high cellular resolution.


Asunto(s)
Inflamación , Leucocitos , Proteómica , Animales , Forma de la Célula , Endotelio/inmunología , Inflamación/inmunología , Leucocitos/inmunología , Ratones , Neutrófilos/inmunología , Proteínas Proto-Oncogénicas/inmunología , Familia-src Quinasas/inmunología
2.
Biostatistics ; 2024 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-38576206

RESUMEN

Mediation analysis is appealing for its ability to improve understanding of the mechanistic drivers of causal effects, but real-world data complexities challenge its successful implementation, including (i) the existence of post-exposure variables that also affect mediators and outcomes (thus, confounding the mediator-outcome relationship), that may also be (ii) multivariate, and (iii) the existence of multivariate mediators. All three challenges are present in the mediation analysis we consider here, where our goal is to estimate the indirect effects of receiving a Section 8 housing voucher as a young child on the risk of developing a psychiatric mood disorder in adolescence that operate through mediators related to neighborhood poverty, the school environment, and instability of the neighborhood and school environments, considered together and separately. Interventional direct and indirect effects (IDE/IIE) accommodate post-exposure variables that confound the mediator-outcome relationship, but currently, no readily implementable nonparametric estimator for IDE/IIE exists that allows for both multivariate mediators and multivariate post-exposure intermediate confounders. The absence of such an IDE/IIE estimator that can easily accommodate both multivariate mediators and post-exposure confounders represents a significant limitation for real-world analyses, because when considering each mediator subgroup separately, the remaining mediator subgroups (or a subset of them) become post-exposure intermediate confounders. We address this gap by extending a recently developed nonparametric estimator for the IDE/IIE to allow for easy incorporation of multivariate mediators and multivariate post-exposure confounders simultaneously. We apply the proposed estimation approach to our analysis, including walking through a strategy to account for other, possibly co-occurring intermediate variables when considering each mediator subgroup separately.

3.
Am J Epidemiol ; 2024 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-38879744

RESUMEN

Studies often report estimates of the average treatment effect (ATE). While the ATE summarizes the effect of a treatment on average, it does not provide any information about the effect of treatment within any individual. A treatment strategy that uses an individual's information to tailor treatment to maximize benefit is known as an optimal dynamic treatment rule (ODTR). Treatment, however, is typically not limited to a single point in time; consequently, learning an optimal rule for a time-varying treatment may involve not just learning the extent to which the comparative treatments' benefits vary across the characteristics of individuals, but also learning the extent to which the comparative treatments' benefits vary as relevant circumstances evolve within an individual. The goal of this paper is to provide a tutorial for estimating ODTR from longitudinal observational and clinical trial data for applied researchers. We describe an approach that uses a doubly-robust unbiased transformation of the conditional average treatment effect. We then learn a time-varying ODTR for when to increase buprenorphine-naloxone (BUP-NX) dose to minimize return-to-regular-opioid-use among patients with opioid use disorder. Our analysis highlights the utility of ODTRs in the context of sequential decision making: the learned ODTR outperforms a clinically defined strategy.

4.
Biostatistics ; 24(3): 686-707, 2023 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-35102366

RESUMEN

Causal mediation analysis has historically been limited in two important ways: (i) a focus has traditionally been placed on binary exposures and static interventions and (ii) direct and indirect effect decompositions have been pursued that are only identifiable in the absence of intermediate confounders affected by exposure. We present a theoretical study of an (in)direct effect decomposition of the population intervention effect, defined by stochastic interventions jointly applied to the exposure and mediators. In contrast to existing proposals, our causal effects can be evaluated regardless of whether an exposure is categorical or continuous and remain well-defined even in the presence of intermediate confounders affected by exposure. Our (in)direct effects are identifiable without a restrictive assumption on cross-world counterfactual independencies, allowing for substantive conclusions drawn from them to be validated in randomized controlled trials. Beyond the novel effects introduced, we provide a careful study of nonparametric efficiency theory relevant for the construction of flexible, multiply robust estimators of our (in)direct effects, while avoiding undue restrictions induced by assuming parametric models of nuisance parameter functionals. To complement our nonparametric estimation strategy, we introduce inferential techniques for constructing confidence intervals and hypothesis tests, and discuss open-source software, the $\texttt{medshift}$$\texttt{R}$ package, implementing the proposed methodology. Application of our (in)direct effects and their nonparametric estimators is illustrated using data from a comparative effectiveness trial examining the direct and indirect effects of pharmacological therapeutics on relapse to opioid use disorder.


Asunto(s)
Análisis de Mediación , Modelos Estadísticos , Humanos , Modelos Teóricos , Causalidad
5.
Psychol Med ; 54(7): 1419-1430, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-37974483

RESUMEN

BACKGROUND: Chronic pain has been extensively explored as a risk factor for opioid misuse, resulting in increased focus on opioid prescribing practices for individuals with such conditions. Physical disability sometimes co-occurs with chronic pain but may also represent an independent risk factor for opioid misuse. However, previous research has not disentangled whether disability contributes to risk independent of chronic pain. METHODS: Here, we estimate the independent and joint adjusted associations between having a physical disability and co-occurring chronic pain condition at time of Medicaid enrollment on subsequent 18-month risk of incident opioid use disorder (OUD) and non-fatal, unintentional opioid overdose among non-elderly, adult Medicaid beneficiaries (2016-2019). RESULTS: We find robust evidence that having a physical disability approximately doubles the risk of incident OUD or opioid overdose, and physical disability co-occurring with chronic pain increases the risks approximately sixfold as compared to having neither chronic pain nor disability. In absolute numbers, those with neither a physical disability nor chronic pain condition have a 1.8% adjusted risk of incident OUD over 18 months of follow-up, those with physical disability alone have an 2.9% incident risk, those with chronic pain alone have a 3.6% incident risk, and those with co-occurring physical disability and chronic pain have a 11.1% incident risk. CONCLUSIONS: These findings suggest that those with a physical disability should receive increased attention from the medical and healthcare communities to reduce their risk of opioid misuse and attendant negative outcomes.


Asunto(s)
Dolor Crónico , Sobredosis de Droga , Sobredosis de Opiáceos , Trastornos Relacionados con Opioides , Adulto , Estados Unidos/epidemiología , Humanos , Persona de Mediana Edad , Dolor Crónico/tratamiento farmacológico , Dolor Crónico/epidemiología , Analgésicos Opioides/efectos adversos , Medicaid , Sobredosis de Opiáceos/tratamiento farmacológico , Sobredosis de Droga/epidemiología , Sobredosis de Droga/tratamiento farmacológico , Pautas de la Práctica en Medicina , Trastornos Relacionados con Opioides/epidemiología , Enfermedad Crónica
6.
Biometrics ; 80(1)2024 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-38412300

RESUMEN

Mediation analysis is a strategy for understanding the mechanisms by which interventions affect later outcomes. However, unobserved confounding concerns may be compounded in mediation analyses, as there may be unobserved exposure-outcome, exposure-mediator, and mediator-outcome confounders. Instrumental variables (IVs) are a popular identification strategy in the presence of unobserved confounding. However, in contrast to the rich literature on the use of IV methods to identify and estimate a total effect of a non-randomized exposure, there has been almost no research into using IV as an identification strategy to identify mediational indirect effects. In response, we define and nonparametrically identify novel estimands-double complier interventional direct and indirect effects-when 2, possibly related, IVs are available, one for the exposure and another for the mediator. We propose nonparametric, robust, efficient estimators for these effects and apply them to a housing voucher experiment.


Asunto(s)
Análisis de Mediación , Factores de Confusión Epidemiológicos
7.
Bioorg Chem ; 144: 107112, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38237390

RESUMEN

We report here the virtual screening design, synthesis and activity of eight new inhibitors of SphK1. For this study we used a pre-trained Graph Convolutional Network (GCN) combined with docking calculations. This exploratory analysis proposed nine compounds from which eight displayed significant inhibitory effect against sphingosine kinase 1 (SphK1) demonstrating a high level of efficacy for this approach. Four of these compounds also displayed anticancer activity against different tumor cell lines, and three of them (5), (6) and (7) have shown a wide inhibitory action against many of the cancer cell line tested, with GI50 below 5 µM, being (5) the most promising with TGI below 10 µM for the half of cell lines. Our results suggest that the three most promising compounds reported here are the pyrimidine-quinolone hybrids (1) and (6) linked by p-aminophenylsulfanyl and o-aminophenol fragments respectively, and (8) without such aryl linker. We also performed an exhaustive study about the molecular interactions that stabilize the different ligands at the binding site of SphK1. This molecular modeling analysis was carried out by using combined techniques: docking calculations, MD simulations and QTAIM analysis. In this study we also included PF543, as reference compound, in order to better understand the molecular behavior of these ligands at the binding site of SphK1.These results provide useful information for the design of new inhibitors of SphK1 possessing these structural scaffolds.


Asunto(s)
Antineoplásicos , Fosfotransferasas (Aceptor de Grupo Alcohol) , Quinolonas , Quinolonas/farmacología , Inhibidores de Proteínas Quinasas , Antineoplásicos/química , Modelos Moleculares , Línea Celular Tumoral , Simulación del Acoplamiento Molecular , Ensayos de Selección de Medicamentos Antitumorales , Proliferación Celular , Relación Estructura-Actividad , Estructura Molecular
8.
Lifetime Data Anal ; 30(1): 213-236, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37620504

RESUMEN

Longitudinal modified treatment policies (LMTP) have been recently developed as a novel method to define and estimate causal parameters that depend on the natural value of treatment. LMTPs represent an important advancement in causal inference for longitudinal studies as they allow the non-parametric definition and estimation of the joint effect of multiple categorical, ordinal, or continuous treatments measured at several time points. We extend the LMTP methodology to problems in which the outcome is a time-to-event variable subject to a competing event that precludes observation of the event of interest. We present identification results and non-parametric locally efficient estimators that use flexible data-adaptive regression techniques to alleviate model misspecification bias, while retaining important asymptotic properties such as [Formula: see text]-consistency. We present an application to the estimation of the effect of the time-to-intubation on acute kidney injury amongst COVID-19 hospitalized patients, where death by other causes is taken to be the competing event.


Asunto(s)
Modelos Estadísticos , Análisis de Supervivencia , Humanos , Simulación por Computador , Estudios Longitudinales , Análisis de Regresión
9.
Entropy (Basel) ; 26(2)2024 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-38392420

RESUMEN

Immunohistochemistry is a powerful technique that is widely used in biomedical research and clinics; it allows one to determine the expression levels of some proteins of interest in tissue samples using color intensity due to the expression of biomarkers with specific antibodies. As such, immunohistochemical images are complex and their features are difficult to quantify. Recently, we proposed a novel method, including a first separation stage based on non-negative matrix factorization (NMF), that achieved good results. However, this method was highly dependent on the parameters that control sparseness and non-negativity, as well as on algorithm initialization. Furthermore, the previously proposed method required a reference image as a starting point for the NMF algorithm. In the present work, we propose a new, simpler and more robust method for the automated, unsupervised scoring of immunohistochemical images based on bright field. Our work is focused on images from tumor tissues marked with blue (nuclei) and brown (protein of interest) stains. The new proposed method represents a simpler approach that, on the one hand, avoids the use of NMF in the separation stage and, on the other hand, circumvents the need for a control image. This new approach determines the subspace spanned by the two colors of interest using principal component analysis (PCA) with dimension reduction. This subspace is a two-dimensional space, allowing for color vector determination by considering the point density peaks. A new scoring stage is also developed in our method that, again, avoids reference images, making the procedure more robust and less dependent on parameters. Semi-quantitative image scoring experiments using five categories exhibit promising and consistent results when compared to manual scoring carried out by experts.

10.
Am J Epidemiol ; 192(5): 748-756, 2023 05 05.
Artículo en Inglés | MEDLINE | ID: mdl-36549900

RESUMEN

Patients with opioid use disorder (OUD) tend to get assigned to one of 3 medications based on the treatment program to which the patient presents (e.g., opioid treatment programs tend to treat patients with methadone, while office-based practices tend to prescribe buprenorphine). It is possible that optimally matching patients with treatment type would reduce the risk of return to regular opioid use (RROU). We analyzed data from 3 comparative effectiveness trials from the US National Institute on Drug Abuse Clinical Trials Network (CTN0027, 2006-2010; CTN0030, 2006-2009; and CTN0051 2014-2017), in which patients with OUD (n = 1,459) were assigned to treatment with either injection extended-release naltrexone (XR-NTX), sublingual buprenorphine-naloxone (BUP-NX), or oral methadone. We learned an individualized rule by which to assign medication type such that risk of RROU during 12 weeks of treatment would be minimized, and then estimated the amount by which RROU risk could be reduced if the rule were applied. Applying our estimated treatment rule would reduce risk of RROU compared with treating everyone with methadone (relative risk (RR) = 0.79, 95% confidence interval (CI): 0.60, 0.97) or treating everyone with XR-NTX (RR = 0.71, 95% CI: 0.47, 0.96). Applying the estimated treatment rule would have resulted in a similar risk of RROU to that of with treating everyone with BUP-NX (RR = 0.92, 95% CI: 0.73, 1.11).


Asunto(s)
Buprenorfina , Trastornos Relacionados con Opioides , Humanos , Antagonistas de Narcóticos/uso terapéutico , Analgésicos Opioides/uso terapéutico , Trastornos Relacionados con Opioides/tratamiento farmacológico , Naltrexona/uso terapéutico , Buprenorfina/uso terapéutico , Combinación Buprenorfina y Naloxona/uso terapéutico , Metadona/uso terapéutico
11.
Am J Epidemiol ; 2023 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-38061692

RESUMEN

Time-varying confounding is a common challenge for causal inference in observational studies with time-varying treatments, long follow-up periods, and participant dropout. Confounder adjustment using traditional approaches can be limited by data sparsity, weight instability and computational issues. The Nicotine Dependence in Teens (NDIT) study is a prospective cohort study involving 24 data collection cycles from 1999 to date, among 1,294 students recruited from 10 high schools in Montreal, Canada, including follow-up into adulthood. Our aim is to estimate associations between the timing of alcohol initiation and the cumulative duration of alcohol use on depression symptoms in adulthood. Based on the target trials framework, we define intention-to-treat and as-treated parameters in a marginal structural model with sex as a potential effect-modifier. We then use the observational data to emulate the trials. For estimation, we use pooled longitudinal target maximum likelihood estimation (LTMLE), a plug-in estimator with double robust and local efficiency properties. We describe strategies for dealing with high-dimensional potential drinking patterns and practical positivity violations due to a long follow-up time, including modifying the effect of interest by removing sparsely observed drinking patterns from the loss function and applying longitudinal modified treatment policies to represent the effect of discouraging drinking.

12.
Biostatistics ; 23(1): 274-293, 2022 01 13.
Artículo en Inglés | MEDLINE | ID: mdl-32529244

RESUMEN

We introduce a novel Bayesian estimator for the class proportion in an unlabeled dataset, based on the targeted learning framework. The procedure requires the specification of a prior (and outputs a posterior) only for the target of inference, and yields a tightly concentrated posterior. When the scientific question can be characterized by a low-dimensional parameter functional, this focus on target prior and posterior distributions perfectly aligns with Bayesian subjectivism. We prove a Bernstein-von Mises-type result for our proposed Bayesian procedure, which guarantees that the posterior distribution converges to the distribution of an efficient, asymptotically linear estimator. In particular, the posterior is Gaussian, doubly robust, and efficient in the limit, under the only assumption that certain nuisance parameters are estimated at slower-than-parametric rates. We perform numerical studies illustrating the frequentist properties of the method. We also illustrate their use in a motivating application to estimate the proportion of embolic strokes of undetermined source arising from occult cardiac sources or large-artery atherosclerotic lesions. Though we focus on the motivating example of the proportion of cases in an unlabeled dataset, the procedure is general and can be adapted to estimate any pathwise differentiable parameter in a non-parametric model.


Asunto(s)
Proyectos de Investigación , Teorema de Bayes , Humanos
13.
Biostatistics ; 23(3): 789-806, 2022 07 18.
Artículo en Inglés | MEDLINE | ID: mdl-33528006

RESUMEN

The same intervention can produce different effects in different sites. Existing transport mediation estimators can estimate the extent to which such differences can be explained by differences in compositional factors and the mechanisms by which mediating or intermediate variables are produced; however, they are limited to consider a single, binary mediator. We propose novel nonparametric estimators of transported interventional (in)direct effects that consider multiple, high-dimensional mediators and a single, binary intermediate variable. They are multiply robust, efficient, asymptotically normal, and can incorporate data-adaptive estimation of nuisance parameters. They can be applied to understand differences in treatment effects across sites and/or to predict treatment effects in a target site based on outcome data in source sites.


Asunto(s)
Modelos Estadísticos , Causalidad , Humanos
14.
BMC Plant Biol ; 23(1): 346, 2023 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-37391695

RESUMEN

BACKGROUND: The solubilization of aluminum ions (Al3+) that results from soil acidity (pH < 5.5) is a limiting factor in oil palm yield. Al can be uptaken by the plant roots affecting DNA replication and cell division and triggering root morphological alterations, nutrient and water deprivation. In different oil palm-producing countries, oil palm is planted in acidic soils, representing a challenge for achieving high productivity. Several studies have reported the morphological, physiological, and biochemical oil palm mechanisms in response to Al-stress. However, the molecular mechanisms are just partially understood. RESULTS: Differential gene expression and network analysis of four contrasting oil palm genotypes (IRHO 7001, CTR 3-0-12, CR 10-0-2, and CD 19 - 12) exposed to Al-stress helped to identify a set of genes and modules involved in oil palm early response to the metal. Networks including the ABA-independent transcription factors DREB1F and NAC and the calcium sensor Calmodulin-like (CML) that could induce the expression of internal detoxifying enzymes GRXC1, PER15, ROMT, ZSS1, BBI, and HS1 against Al-stress were identified. Also, some gene networks pinpoint the role of secondary metabolites like polyphenols, sesquiterpenoids, and antimicrobial components in reducing oxidative stress in oil palm seedlings. STOP1 expression could be the first step of the induction of common Al-response genes as an external detoxification mechanism mediated by ABA-dependent pathways. CONCLUSIONS: Twelve hub genes were validated in this study, supporting the reliability of the experimental design and network analysis. Differential expression analysis and systems biology approaches provide a better understanding of the molecular network mechanisms of the response to aluminum stress in oil palm roots. These findings settled a basis for further functional characterization of candidate genes associated with Al-stress in oil palm.


Asunto(s)
Aluminio , Calcio , Aluminio/toxicidad , Reproducibilidad de los Resultados , Calmodulina , División Celular
15.
J Gen Intern Med ; 38(6): 1384-1392, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-36441365

RESUMEN

BACKGROUND: Primary care "teamlets" in which a staff member and physician consistently work together might provide a simple, cost-effective way to improve care, with or without insertion within a team. OBJECTIVE: To determine the prevalence and performance of teamlets and teams. DESIGN: Cross-sectional observational study linking survey responses to Medicare claims. PARTICIPANTS: Six hundred eighty-eight general internists and family physicians. INTERVENTIONS: Based on survey responses, physicians were assigned to one of four teamlet/team categories (e.g., teamlet/no team) and, in secondary analyses, to one of eight teamlet/team categories that classified teamlets into high, medium, and low collaboration as perceived by the physician (e.g., teamlet perceived-high collaboration/no team). MAIN MEASURES: Descriptive: percentage of physicians in teamlet/team categories. OUTCOME MEASURES: physician burnout; ambulatory care sensitive emergency department and hospital admissions; Medicare spending. KEY RESULTS: 77.4% of physicians practiced in teamlets; 36.7% in teams. Of the four categories, 49.1% practiced in the teamlet/no team category; 28.3% in the teamlet/team category; 8.4% in no teamlet/team; 14.1% in no teamlet/no team. 15.7%, 47.4%, and 14.4% of physicians practiced in perceived high-, medium-, and low-collaboration teamlets. Physicians who practiced neither in a teamlet nor in a team had significantly lower rates of burnout compared to the three teamlet/team categories. There were no consistent, significant differences in outcomes or Medicare spending by teamlet/team or teamlet perceived-collaboration/team categories compared to no teamlet/no team, for Medicare beneficiaries in general or for dual-eligible beneficiaries. CONCLUSIONS: Most general internists and family physicians practice in teamlets, and some practice in teams, but neither practicing in a teamlet, in a team, or in the two together was associated with lower physician burnout, better outcomes for patients, or lower Medicare spending. Further study is indicated to investigate whether certain types of teamlet, teams, or teamlets within teams can achieve higher performance.


Asunto(s)
Médicos , Atención Primaria de Salud , Anciano , Humanos , Estados Unidos/epidemiología , Estudios Transversales , Medicare , Agotamiento Psicológico
16.
Biometrics ; 79(4): 3126-3139, 2023 12.
Artículo en Inglés | MEDLINE | ID: mdl-36905172

RESUMEN

Natural direct and indirect effects are mediational estimands that decompose the average treatment effect and describe how outcomes would be affected by contrasting levels of a treatment through changes induced in mediator values (in the case of the indirect effect) or not through induced changes in the mediator values (in the case of the direct effect). Natural direct and indirect effects are not generally point-identified in the presence of a treatment-induced confounder; however, they may be identified if one is willing to assume monotonicity between the treatment and the treatment-induced confounder. We argue that this assumption may be reasonable in the relatively common encouragement-design trial setting, where the intervention is randomized treatment assignment and the treatment-induced confounder is whether or not treatment was actually taken/adhered to. We develop efficiency theory for the natural direct and indirect effects under this monotonicity assumption, and use it to propose a nonparametric, multiply robust estimator. We demonstrate the finite sample properties of this estimator using a simulation study, and apply it to data from the Moving to Opportunity Study to estimate the natural direct and indirect effects of being randomly assigned to receive a Section 8 housing voucher-the most common form of federal housing assistance-on risk developing any mood or externalizing disorder among adolescent boys, possibly operating through various school and community characteristics.


Asunto(s)
Modelos Estadísticos , Instituciones Académicas , Masculino , Adolescente , Humanos , Simulación por Computador
17.
Epidemiology ; 33(5): 689-698, 2022 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-35944151

RESUMEN

Violations of the positivity assumption (also called the common support condition) challenge health policy research and can result in significant bias, large variance, and invalid inference. We define positivity in the single- and multiple-timepoint (i.e., longitudinal) health policy evaluation setting, and discuss real-world threats to positivity. We show empirical evidence of the practical positivity violations that can result when attempting to estimate the effects of health policies (in this case, Naloxone Access Laws). In such scenarios, an alternative is to estimate the effect of a shift in law enactment (e.g., the effect if enactment had been delayed by some number of years). Such an effect corresponds to what is called a modified treatment policy, and dramatically weakens the required positivity assumption, thereby offering a means to estimate policy effects even in scenarios with serious positivity problems. We apply the approach to define and estimate the longitudinal effects of Naloxone Access Laws on opioid overdose rates.


Asunto(s)
Sobredosis de Droga , Sobredosis de Opiáceos , Analgésicos Opioides , Sobredosis de Droga/tratamiento farmacológico , Sobredosis de Droga/epidemiología , Sobredosis de Droga/prevención & control , Política de Salud , Humanos , Naloxona/uso terapéutico , Antagonistas de Narcóticos/uso terapéutico
18.
J Stroke Cerebrovasc Dis ; 31(8): 106589, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35689935

RESUMEN

OBJECTIVES: To derive models that identify patients with COVID-19 at high risk for stroke. MATERIALS AND METHODS: We used data from the AHA's Get With The Guidelines® COVID-19 Cardiovascular Disease Registry to generate models for predicting stroke risk among adults hospitalized with COVID-19 at 122 centers from March 2020-March 2021. To build our models, we used data on demographics, comorbidities, medications, and vital sign and laboratory values at admission. The outcome was a cerebrovascular event (stroke, TIA, or cerebral vein thrombosis). First, we used Cox regression with cross validation techniques to identify factors associated with the outcome in both univariable and multivariable analyses. Then, we assigned points for each variable based on corresponding coefficients to create a prediction score. Second, we used machine learning techniques to create risk estimators using all available covariates. RESULTS: Among 21,420 patients hospitalized with COVID-19, 312 (1.5%) had a cerebrovascular event. Using traditional Cox regression, we created/validated a COVID-19 stroke risk score with a C-statistic of 0.66 (95% CI, 0.60-0.72). The CANDLE score assigns 1 point each for prior cerebrovascular disease, afebrile temperature, no prior pulmonary disease, history of hypertension, leukocytosis, and elevated systolic blood pressure. CANDLE stratified risk of an acute cerebrovascular event according to low- (0-1: 0.2% risk), medium- (2-3: 1.1% risk), and high-risk (4-6: 2.1-3.0% risk) groups. Machine learning estimators had similar discriminatory performance as CANDLE: C-statistics, 0.63-0.69. CONCLUSIONS: We developed a practical clinical score, with similar performance to machine learning estimators, to help stratify stroke risk among patients hospitalized with COVID-19.


Asunto(s)
COVID-19 , Accidente Cerebrovascular , Adulto , COVID-19/complicaciones , COVID-19/diagnóstico , Hospitalización , Humanos , Medición de Riesgo/métodos , Factores de Riesgo , Accidente Cerebrovascular/diagnóstico , Accidente Cerebrovascular/epidemiología , Accidente Cerebrovascular/terapia
19.
Entropy (Basel) ; 24(4)2022 Apr 13.
Artículo en Inglés | MEDLINE | ID: mdl-35455209

RESUMEN

In many research laboratories, it is essential to determine the relative expression levels of some proteins of interest in tissue samples. The semi-quantitative scoring of a set of images consists of establishing a scale of scores ranging from zero or one to a maximum number set by the researcher and assigning a score to each image that should represent some predefined characteristic of the IHC staining, such as its intensity. However, manual scoring depends on the judgment of an observer and therefore exposes the assessment to a certain level of bias. In this work, we present a fully automatic and unsupervised method for comparative biomarker quantification in histopathological brightfield images. The method relies on a color separation method that discriminates between two chromogens expressed as brown and blue colors robustly, independent of color variation or biomarker expression level. For this purpose, we have adopted a two-stage stain separation approach in the optical density space. First, a preliminary separation is performed using a deconvolution method in which the color vectors of the stains are determined after an eigendecomposition of the data. Then, we adjust the separation using the non-negative matrix factorization method with beta divergences, initializing the algorithm with the matrices resulting from the previous step. After that, a feature vector of each image based on the intensity of the two chromogens is determined. Finally, the images are annotated using a systematically initialized k-means clustering algorithm with beta divergences. The method clearly defines the initial boundaries of the categories, although some flexibility is added. Experiments for the semi-quantitative scoring of images in five categories have been carried out by comparing the results with the scores of four expert researchers yielding accuracies that range between 76.60% and 94.58%. These results show that the proposed automatic scoring system, which is definable and reproducible, produces consistent results.

20.
Plant Foods Hum Nutr ; 77(3): 460-466, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35932411

RESUMEN

Lepidium meyenii Walp (red maca) is a high Andean plant cultivated since the Incas and has innumerable therapeutic properties. The study aims to identify its phytochemical composition using UHPLC-ESI-MS/MS, and evaluate its effects on acrylamide-induced oxidative stress. The lyophilized aqueous extract of red maca (LAqE-RM) was orally administered in doses of 1 and 2 g/kg body weight for 4 weeks. Malondialdehyde (MDA) levels in erythrocytes, brain, and liver, as well as hepatic levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were determined. Administration of acrylamide for 2 and 4 weeks significantly increased (p < 0.001) MDA levels in erythrocytes, brain, and liver. However, LAqE-RM prevented (p < 0.001) an increase in MDA levels in all tissues studied. Likewise, the groups treated with LAqE-RM presented significantly (p < 0.001) lower levels of ALT and AST compared to the control. Treatment with LAqE-RM ameliorated the acrylamide-induced oxidative stress by reducing MDA levels in erythrocytes, brain, and liver and by lowering liver levels of ALT and AST in a dose-dependent manner. Twenty-five secondary metabolites were identified and characterized from LAqE-RM based on UHPLC mass spectrophotometry. These include carbolines, alkamides, fatty acids, and macamides, which are probably involved in their antioxidant protective role.


Asunto(s)
Lepidium , Acrilamida/toxicidad , Animales , Cromatografía Líquida de Alta Presión , Suplementos Dietéticos , Lepidium/química , Hígado , Estrés Oxidativo , Fitoquímicos , Extractos Vegetales/química , Extractos Vegetales/farmacología , Ratas , Espectrometría de Masas en Tándem
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