Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 62
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Anim Biotechnol ; 35(1): 2356110, 2024 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-38804592

RESUMEN

The inducing activation event of secondary hair follicle (SHF)-stem cells is considered a key biological process in the SHF regeneration, and the morphogenesis of cashmere fiber in cashmere goats. The miR-361-5p was essentially implicated in the induced activation of SHF-stem cells of cashmere goats, but its functional mechanisms are unclear. Here, we confirmed miR-361-5p was significantly downregulated in anagen SHF bugle of cashmere goats compared with that at telogen, and miR-361-5p expression was significantly lower in SHF-stem cells after activation than its counterpart before activation. Further, we found that miR-361-5p could negatively regulate the induced activation event of SHF-stem cells in cashmere goats. Mechanistically, through dual-luciferase reporter assays, miR-361-5p specifically bound with FOXM1 mRNA in SHF-stem cells of cashmere goats and negatively regulated the expression of FOXM1 gene. Also, through overexpression/knockdown analysis of FOXM1 gene, our results indicated that FOXM1 upregulated the expression of Wnt/ß-catenin pathway related genes in SHF-stem cells. Moreover, based on TOP/FOP-flash Wnt report assays, the knockdown of miR-361-5p promotes the Wnt/ß-catenin pathway activation through upregulating the FOXM1 expression in SHF-stem cells. Finally, we demonstrated that miR-361-5p negatively regulated the induced activation of SHF-stem cells through FOXM1 mediated Wnt/ß-catenin pathway in cashmere goats.


Asunto(s)
Proteína Forkhead Box M1 , Cabras , Folículo Piloso , MicroARNs , Células Madre , Vía de Señalización Wnt , Animales , Cabras/genética , MicroARNs/genética , MicroARNs/metabolismo , Vía de Señalización Wnt/genética , Folículo Piloso/metabolismo , Proteína Forkhead Box M1/genética , Proteína Forkhead Box M1/metabolismo , Células Madre/fisiología , Células Madre/metabolismo , Técnicas de Silenciamiento del Gen
2.
J Natl Compr Canc Netw ; 21(3): 257-264, 2023 02 22.
Artículo en Inglés | MEDLINE | ID: mdl-36812939

RESUMEN

BACKGROUND: Trifluridine/Tipiracil (TAS-102) and regorafenib are FDA-approved in the United States for treatment of refractory metastatic colorectal cancer (mCRC). FDA approvals of these agents were based on modest improvements in overall survival (OS) compared with best supportive care + placebo in the RECOURSE and CORRECT trials, respectively. This study compared real-world clinical outcomes with the use of these agents. METHODS: A nationwide deidentified electronic health record-derived database was reviewed for patients diagnosed with mCRC between 2015 and 2020. Patients who received at least 2 lines of standard systemic therapy followed by treatment with either TAS-102 or regorafenib were included for analysis. Kaplan-Meier and propensity score-weighted proportional hazards models were used to compare survival outcomes between groups. RESULTS: The records of 22,078 patients with mCRC were reviewed. Of these, 1,937 patients received at least 2 lines of standard therapy followed by regorafenib and/or TAS-102. Median OS for the TAS-102 alone or prior regorafenib group (n=1,016) was 6.66 months (95% CI, 6.16-7.18 months) compared with 6.30 months (95% CI, 5.80-6.79 months) for regorafenib alone or prior to TAS-102 (n=921; P=.36). A propensity score-weighted analysis controlling for potential confounders did not demonstrate a significant difference in survival between groups (hazard ratio, 0.99; 95% CI, 0.90-1.09; P=.82). A subgroup analysis did not identify any significant differences in outcomes regarding age, performance status, tumor sidedness, microsatellite instability status, or RAS/RAF status. CONCLUSIONS: This analysis of real-world data found that OS was similar for patients with mCRC who were treated with TAS-102 compared with regorafenib. Median OS with both agents in a real-world setting was similar to that shown in the clinical trials that led to their approvals. A prospective trial comparing TAS-102 and regorafenib would unlikely change current management of patients with refractory mCRC.


Asunto(s)
Neoplasias del Colon , Neoplasias Colorrectales , Neoplasias del Recto , Humanos , Estados Unidos , Trifluridina/uso terapéutico , Uracilo/uso terapéutico , Estudios Prospectivos , Neoplasias Colorrectales/patología , Compuestos de Fenilurea/uso terapéutico , Combinación de Medicamentos , Neoplasias del Colon/tratamiento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico
3.
Anim Biotechnol ; 34(3): 482-494, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-34550847

RESUMEN

Circular RNAs (circRNAs), a novel class of non-coding RNAs, can interact with miRNAs through a sequence-driven sponge mechanism, thereby regulating the expression of their downstream target genes. CircRNA-1967 was found in secondary hair follicles (SHFs) of cashmere goats, but its functions are not clear. Here, we showed that both circRNA-1967 and its host gene BNC2 had significantly higher expression in SHF bulge at anagen than those at telogen of cashmere goats. Also, circRNA-1967 participates in the differentiation of SHF stem cells (SHF-SCs) into hair follicle lineage in cashmere goats. RNA pull-down assay verified that circRNA-1967 interacts with miR-93-3p. We also indicated that circRNA-1967 promoted LEF1 expression in SHF-SCs of cashmere goats. By dual-luciferase reporter analysis, we found that circRNA-1967 up-regulated LEF1 expression through the miR-93-3p-mediated pathway. The results from this study demonstrated that circRNA-1967 participated in the differentiation of goat SHF-SCs into hair follicle lineage by sponging miR-93-3p to enhance LEF1 expression. Our founding might constitute a novel pathway for revealing the potential mechanism of the differentiation of SHF-SCs into hair follicle lineage in cashmere goats. Also, these results provided a valuable basis for further enhancing the intrinsic regeneration of cashmere goat SHFs with the formation and growth of cashmere fibers.


Asunto(s)
MicroARNs , ARN Circular , Animales , ARN Circular/genética , ARN Circular/metabolismo , Folículo Piloso/metabolismo , Cabras , MicroARNs/genética , MicroARNs/metabolismo , Diferenciación Celular/genética
4.
BMC Genomics ; 23(1): 670, 2022 Sep 26.
Artículo en Inglés | MEDLINE | ID: mdl-36162976

RESUMEN

BACKGROUND: Abiotic stresses have increasingly serious effects on the growth and yield of crops. Cold stress, in particular, is an increasing problem. In this study, Fragaria daltoniana and F. vesca were determined to be cold-resistant and cold-sensitive species, respectively. Integrated transcriptomics and metabolomics methods were used to analyze the regulatory mechanism of abscisic acid (ABA) in F. daltoniana and F. vesca in their response to low temperature stress. RESULTS: F. daltoniana and F. vesca increased their ABA content under low temperature stress by upregulating the expression of the ABA biosynthetic pathway gene NCED and downregulating the expression of the ABA degradative gene CYP707A. Both types of regulation increased the accumulation of glucose and fructose, resulting in a reduction of damage under low temperature stress. Twelve transcription factors were found to be involved in the ABA regulatory pathway. The strong cold tolerance of F. daltoniana could be owing to its higher levels of ABA that accumulated compared with those in F. vesca under low temperature stress. In addition, the gene ABF2, which is related to the transduction of glucose signaling, was significantly upregulated in the leaves of F. daltoniana, while it was downregulated in the leaves of F. vesca under low temperature stress. This could contribute to the higher levels of glucose signal transduction in F. daltoniana. Thus, this could explain the higher peroxidase activity and lower damage to cell membranes in the leaves of F. daltoniana compared with F. vesca under low temperature stress, which endows the former with stronger cold tolerance. CONCLUSIONS: Under low temperature stress, the differences in the accumulation of ABA and the expression trends of ABF2 and ABF4 in different species of wild strawberries may be the primary reason for their differences in cold tolerance. Our results provide an important empirical reference and technical support for breeding resistant cultivated strawberry plants.


Asunto(s)
Ácido Abscísico , Fragaria , Ácido Abscísico/metabolismo , Frío , Respuesta al Choque por Frío , Fragaria/genética , Fragaria/metabolismo , Fructosa , Regulación de la Expresión Génica de las Plantas , Glucosa/metabolismo , Peroxidasas/metabolismo , Fitomejoramiento , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Factores de Transcripción/metabolismo
5.
Am J Hum Genet ; 104(5): 802-814, 2019 05 02.
Artículo en Inglés | MEDLINE | ID: mdl-30982610

RESUMEN

Whole-genome sequencing (WGS) studies are being widely conducted in order to identify rare variants associated with human diseases and disease-related traits. Classical single-marker association analyses for rare variants have limited power, and variant-set-based analyses are commonly used by researchers for analyzing rare variants. However, existing variant-set-based approaches need to pre-specify genetic regions for analysis; hence, they are not directly applicable to WGS data because of the large number of intergenic and intron regions that consist of a massive number of non-coding variants. The commonly used sliding-window method requires the pre-specification of fixed window sizes, which are often unknown as a priori, are difficult to specify in practice, and are subject to limitations given that the sizes of genetic-association regions are likely to vary across the genome and phenotypes. We propose a computationally efficient and dynamic scan-statistic method (Scan the Genome [SCANG]) for analyzing WGS data; this method flexibly detects the sizes and the locations of rare-variant association regions without the need to specify a prior, fixed window size. The proposed method controls for the genome-wise type I error rate and accounts for the linkage disequilibrium among genetic variants. It allows the detected sizes of rare-variant association regions to vary across the genome. Through extensive simulated studies that consider a wide variety of scenarios, we show that SCANG substantially outperforms several alternative methods for detecting rare-variant-associations while controlling for the genome-wise type I error rates. We illustrate SCANG by analyzing the WGS lipids data from the Atherosclerosis Risk in Communities (ARIC) study.


Asunto(s)
Algoritmos , Biología Computacional/métodos , Variación Genética , Genoma Humano , Estudio de Asociación del Genoma Completo , Secuenciación Completa del Genoma/métodos , Humanos , Desequilibrio de Ligamiento , Modelos Genéticos
6.
Biometrics ; 78(1): 337-351, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-33215693

RESUMEN

Optimal individualized treatment rules (ITRs) provide customized treatment recommendations based on subject characteristics to maximize clinical benefit in accordance with the objectives in precision medicine. As a result, there is growing interest in developing statistical tools for estimating optimal ITRs in evidence-based research. In health economic perspectives, policy makers consider the tradeoff between health gains and incremental costs of interventions to set priorities and allocate resources. However, most work on ITRs has focused on maximizing the effectiveness of treatment without considering costs. In this paper, we jointly consider the impact of effectiveness and cost on treatment decisions and define ITRs under a composite-outcome setting, so that we identify the most cost-effective ITR that accounts for individual-level heterogeneity through direct optimization. In particular, we propose a decision-tree-based statistical learning algorithm that uses a net-monetary-benefit-based reward to provide nonparametric estimations of the optimal ITR. We provide several approaches to estimating the reward underlying the ITR as a function of subject characteristics. We present the strengths and weaknesses of each approach and provide practical guidelines by comparing their performance in simulation studies. We illustrate the top-performing approach from our simulations by evaluating the projected 15-year personalized cost-effectiveness of the intensive blood pressure control of the Systolic Blood Pressure Intervention Trial (SPRINT) study.


Asunto(s)
Algoritmos , Medicina de Precisión , Simulación por Computador , Análisis Costo-Beneficio , Proyectos de Investigación
7.
Pain Med ; 23(6): 1127-1137, 2022 05 30.
Artículo en Inglés | MEDLINE | ID: mdl-34613379

RESUMEN

OBJECTIVE: The Fear-Avoidance Model (FAM) of chronic pain posits that pain catastrophizing and fear-avoidance beliefs are prognostic for disability and chronicity. In acute low-back pain, early physical therapy (PT) is effective in reducing disability in some patients. How early PT impacts short- and long-term changes in disability for patients with acute pain is unknown. Based on the FAM, we hypothesized that early reductions in pain catastrophizing and fear-avoidance beliefs would mediate early PT's effect on changes in disability (primary outcome) and pain intensity (secondary outcome) over 3 months and 1 year. SUBJECTS: Participants were 204 patients with low-back pain of <16 days duration, who enrolled in a clinical trial (NCT01726803) comparing early PT sessions or usual care provided over 4 weeks. METHODS: Patients completed the Pain Catastrophizing Scale (PCS), Fear-Avoidance Beliefs Questionnaire (FABQ work and physical activity scales), and outcomes (Oswestry Disability Index and Numeric Pain Rating Scale) at baseline, 4 weeks, 3 months, and 1 year. We applied longitudinal mediation analysis with single and multiple mediators. RESULTS: Early PT led to improvements in disability and pain over 3 months but not 1 year. In the single mediator model, 4-week reductions in pain catastrophizing mediated early PT's effects on 3-month disability and pain intensity improvements, explaining 16% and 22% of the association, respectively, but the effects were small. Pain catastrophizing and fear-avoidance beliefs did not jointly mediate these associations. CONCLUSIONS: In acute low-back pain, early PT may improve disability and pain outcomes at least partly through reducing patients' catastrophizing.


Asunto(s)
Dolor Agudo , Dolor de la Región Lumbar , Catastrofización , Evaluación de la Discapacidad , Miedo , Humanos , Dolor de la Región Lumbar/rehabilitación , Modalidades de Fisioterapia , Encuestas y Cuestionarios
8.
J Sci Food Agric ; 102(8): 3287-3296, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-34799861

RESUMEN

BACKGROUND: Strawberries have become one of the most popular fruits because of their unique flavor and high nutritional value. Fruit quality and price are the most important criteria that determine consumer acceptability. Fragaria nilgerrensis and Fragaria pentaphylla are two wild Asian diploid strawberry species that differ in fruit color, taste, and aroma. To understand the molecular mechanisms involved in the formation of high-quality strawberry fruit, we integrated transcriptomics and metabolomics research methods to compare the metabolic and biosynthetic mechanisms of the two Fragaria species. RESULTS: F. nilgerrensis fruit has higher amino acid and lipid contents and a higher sugar-to-acid ratio than F. pentaphylla fruit does, underlying their superior nutritional value, aroma, firmness, and taste. Compared with F. nilgerrensis fruit, F. pentaphylla fruit contained more flavonoids, indicating its enhanced color and health benefits. In addition, candidate structural genes that regulate the biosynthesis of flavonoids, amino acids, and glycerophospholipids in the two strawberry fruit were screened. CONCLUSIONS: The differences in aroma, firmness, and taste between F. nilgerrensis fruit and F. pentaphylla fruit are probably due to differences in their amino acid and lipid contents, as well as the difference in their sugar-to-acid ratios. Eight key structural genes that may play important roles in the biosynthesis of amino acids, lipids, and flavonoids were identified. © 2021 Society of Chemical Industry.


Asunto(s)
Fragaria , Aminoácidos/metabolismo , Flavonoides/metabolismo , Fragaria/genética , Fragaria/metabolismo , Frutas/genética , Frutas/metabolismo , Lípidos , Metabolómica/métodos , Azúcares/metabolismo , Transcriptoma
9.
Emerg Infect Dis ; 27(11): 2786-2794, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34469285

RESUMEN

We aimed to generate an unbiased estimate of the incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in 4 urban counties in Utah, USA. We used a multistage sampling design to randomly select community-representative participants >12 years of age. During May 4-June 30, 2020, we collected serum samples and survey responses from 8,108 persons belonging to 5,125 households. We used a qualitative chemiluminescent microparticle immunoassay to detect SARS-CoV-2 IgG in serum samples. We estimated the overall seroprevalence to be 0.8%. The estimated seroprevalence-to-case count ratio was 2.5, corresponding to a detection fraction of 40%. Only 0.2% of participants from whom we collected nasopharyngeal swab samples had SARS-CoV-2-positive reverse transcription PCR results. SARS-CoV-2 antibody prevalence during the study was low, and prevalence of PCR-positive cases was even lower. The comparatively high SARS-CoV-2 detection rate (40%) demonstrates the effectiveness of Utah's testing strategy and public health response.


Asunto(s)
COVID-19 , SARS-CoV-2 , Anticuerpos Antivirales , Humanos , Probabilidad , Estudios Seroepidemiológicos , Utah/epidemiología
10.
Am J Hum Genet ; 101(6): 888-902, 2017 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-29198723

RESUMEN

Genome-wide association studies have identified hundreds of genetic variants associated with blood pressure (BP), but sequence variation accounts for a small fraction of the phenotypic variance. Epigenetic changes may alter the expression of genes involved in BP regulation and explain part of the missing heritability. We therefore conducted a two-stage meta-analysis of the cross-sectional associations of systolic and diastolic BP with blood-derived genome-wide DNA methylation measured on the Infinium HumanMethylation450 BeadChip in 17,010 individuals of European, African American, and Hispanic ancestry. Of 31 discovery-stage cytosine-phosphate-guanine (CpG) dinucleotides, 13 replicated after Bonferroni correction (discovery: N = 9,828, p < 1.0 × 10-7; replication: N = 7,182, p < 1.6 × 10-3). The replicated methylation sites are heritable (h2 > 30%) and independent of known BP genetic variants, explaining an additional 1.4% and 2.0% of the interindividual variation in systolic and diastolic BP, respectively. Bidirectional Mendelian randomization among up to 4,513 individuals of European ancestry from 4 cohorts suggested that methylation at cg08035323 (TAF1B-YWHAQ) influences BP, while BP influences methylation at cg00533891 (ZMIZ1), cg00574958 (CPT1A), and cg02711608 (SLC1A5). Gene expression analyses further identified six genes (TSPAN2, SLC7A11, UNC93B1, CPT1A, PTMS, and LPCAT3) with evidence of triangular associations between methylation, gene expression, and BP. Additional integrative Mendelian randomization analyses of gene expression and DNA methylation suggested that the expression of TSPAN2 is a putative mediator of association between DNA methylation at cg23999170 and BP. These findings suggest that heritable DNA methylation plays a role in regulating BP independently of previously known genetic variants.


Asunto(s)
Presión Sanguínea/genética , Metilación de ADN/genética , Proteínas del Tejido Nervioso/genética , Tetraspaninas/genética , Anciano , Islas de CpG/genética , Estudios Transversales , Epigénesis Genética/genética , Variación Genética/genética , Estudio de Asociación del Genoma Completo , Humanos , Análisis de la Aleatorización Mendeliana , Persona de Mediana Edad , Sitios de Carácter Cuantitativo/genética
11.
J Am Soc Nephrol ; 30(8): 1523-1533, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-31324734

RESUMEN

BACKGROUND: The Systolic BP Intervention Trial (SPRINT) found that intensive versus standard systolic BP control (targeting <120 or <140 mm Hg, respectively) reduced the risks of death and major cardiovascular events in persons with elevated cardiovascular disease risk. However, the intensive intervention was associated with an early decline in eGFR, and the clinical implications of this early decline are unclear. METHODS: In a post hoc analysis of SPRINT, we defined change in eGFR as the percentage change in eGFR at 6 months compared with baseline. We performed causal mediation analyses to separate the overall effects of the randomized systolic BP intervention on the SPRINT primary cardiovascular composite and all-cause mortality into indirect effects (mediated by percentage change in eGFR) and direct effects (mediated through pathways other than percentage change in eGFR). RESULTS: About 10.3% of the 4270 participants in the intensive group had a ≥20% eGFR decline versus 4.4% of the 4256 participants in the standard arm (P<0.001). After the 6-month visit, there were 591 cardiovascular composite events during 27,849 person-years of follow-up. The hazard ratios for total effect, direct effect, and indirect effect of the intervention on the cardiovascular composite were 0.67 (95% confidence interval [95% CI], 0.56 to 0.78), 0.68 (95% CI, 0.57 to 0.79), and 0.99 (95% CI, 0.95 to 1.03), respectively. All-cause mortality results were similar. CONCLUSIONS: Although intensive systolic BP lowering resulted in greater early decline in eGFR, there was no evidence that the reduction in eGFR owing to intensive systolic BP lowering attenuated the beneficial effects of this intervention on cardiovascular events or all-cause mortality.


Asunto(s)
Enfermedades Cardiovasculares/complicaciones , Enfermedades Cardiovasculares/prevención & control , Tasa de Filtración Glomerular , Hipertensión/complicaciones , Hipertensión/terapia , Sístole , Anciano , Antihipertensivos/uso terapéutico , Presión Sanguínea , Progresión de la Enfermedad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Modelos de Riesgos Proporcionales , Análisis de Regresión , Riesgo , Resultado del Tratamiento
12.
Genet Epidemiol ; 41(8): 824-833, 2017 12.
Artículo en Inglés | MEDLINE | ID: mdl-29082545

RESUMEN

Mediation analysis helps researchers assess whether part or all of an exposure's effect on an outcome is due to an intermediate variable. The indirect effect can help in designing interventions on the mediator as opposed to the exposure and better understanding the outcome's mechanisms. Mediation analysis has seen increased use in genome-wide epidemiological studies to test for an exposure of interest being mediated through a genomic measure such as gene expression or DNA methylation (DNAm). Testing for the indirect effect is challenged by the fact that the null hypothesis is composite. We examined the performance of commonly used mediation testing methods for the indirect effect in genome-wide mediation studies. When there is no association between the exposure and the mediator and no association between the mediator and the outcome, we show that these common tests are overly conservative. This is a case that will arise frequently in genome-wide mediation studies. Caution is hence needed when applying the commonly used mediation tests in genome-wide mediation studies. We evaluated the performance of these methods using simulation studies, and performed an epigenome-wide mediation association study in the Normative Aging Study, analyzing DNAm as a mediator of the effect of pack-years on FEV1 .


Asunto(s)
Estudio de Asociación del Genoma Completo , Modelos Genéticos , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Metilación de ADN , Epigenómica , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , Proteínas Represoras/genética
13.
J Biopharm Stat ; 28(2): 362-381, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-28934002

RESUMEN

A personalized treatment policy requires defining the optimal treatment for each patient based on their clinical and other characteristics. Here we consider a commonly encountered situation in practice, when analyzing data from observational cohorts, that there are auxiliary variables which affect both the treatment and the outcome, yet these variables are not of primary interest to be included in a generalizable treatment strategy. Furthermore, there is not enough prior knowledge of the effect of the treatments or of the importance of the covariates for us to explicitly specify the dependency between the outcome and different covariates, thus we choose a model that is flexible enough to accommodate the possibly complex association of the outcome on the covariates. We consider observational studies with a survival outcome and propose to use Random Survival Forest with Weighted Bootstrap (RSFWB) to model the counterfactual outcomes while marginalizing over the auxiliary covariates. By maximizing the restricted mean survival time, we estimate the optimal regime for a target population based on a selected set of covariates. Simulation studies illustrate that the proposed method performs reliably across a range of different scenarios. We further apply RSFWB to a prostate cancer study.


Asunto(s)
Simulación por Computador/estadística & datos numéricos , Modelos Estadísticos , Estudios Observacionales como Asunto/estadística & datos numéricos , Medicina de Precisión/métodos , Neoplasias de la Próstata/mortalidad , Análisis de Supervivencia , Humanos , Masculino , Medicina de Precisión/estadística & datos numéricos , Probabilidad , Neoplasias de la Próstata/tratamiento farmacológico , Proyectos de Investigación/estadística & datos numéricos , Estadísticas no Paramétricas , Resultado del Tratamiento
14.
Biometrics ; 73(2): 635-645, 2017 06.
Artículo en Inglés | MEDLINE | ID: mdl-27893926

RESUMEN

Prostate cancer patients are closely followed after the initial therapy and salvage treatment may be prescribed to prevent or delay cancer recurrence. The salvage treatment decision is usually made dynamically based on the patient's evolving history of disease status and other time-dependent clinical covariates. A multi-center prostate cancer observational study has provided us data on longitudinal prostate specific antigen (PSA) measurements, time-varying salvage treatment, and cancer recurrence time. These data enable us to estimate the best dynamic regime of salvage treatment, while accounting for the complicated confounding of time-varying covariates present in the data. A Random Forest based method is used to model the probability of regime adherence and inverse probability weights are used to account for the complexity of selection bias in regime adherence. The optimal regime is then identified by the largest restricted mean survival time. We conduct simulation studies with different PSA trends to mimic both simple and complex regime adherence mechanisms. The proposed method can efficiently accommodate complex and possibly unknown adherence mechanisms, and it is robust to cases where the proportional hazards assumption is violated. We apply the method to data collected from the observational study and estimate the best salvage treatment regime in managing the risk of prostate cancer recurrence.


Asunto(s)
Neoplasias de la Próstata , Humanos , Masculino , Recurrencia Local de Neoplasia , Antígeno Prostático Específico , Terapia Recuperativa
15.
Cancer ; 120(17): 2704-12, 2014 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-24830761

RESUMEN

BACKGROUND: Proinflammatory cytokine levels may be associated with cancer stage, recurrence, and survival. The objective of this study was to determine whether cytokine levels were associated with dietary patterns and fat-soluble micronutrients in patients with previously untreated head and neck squamous cell carcinoma (HNSCC). METHODS: This was a cross-sectional study of 160 patients with newly diagnosed HNSCC who completed pretreatment food frequency questionnaires (FFQs) and health surveys. Dietary patterns were derived from FFQs using principal component analysis. Pretreatment serum levels of the proinflammatory cytokines interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), and interferon gamma (IFN-γ) were measured using an enzyme-linked immunosorbent assay, and serum carotenoid and tocopherol levels were measured by high-performance liquid chromatography. Multivariable ordinal logistic regression models examined associations between cytokines and quartiles of reported and serum dietary variables. RESULTS: Three dietary patterns emerged: whole foods, Western, and convenience foods. In multivariable analyses, higher whole foods pattern scores were significantly associated with lower levels of IL-6, TNF-α, and IFN-γ (P ≤ .001, P = .008, and P = .03, respectively). Significant inverse associations were reported between IL-6, TNF-α, and IFN-γ levels and quartiles of total reported carotenoid intake (P = .006, P = .04, and P = .04, respectively). There was an inverse association between IFN-γ levels and serum α-tocopherol levels (P = .03). CONCLUSIONS: Consuming a pretreatment diet rich in vegetables, fruit, fish, poultry, and whole grains may be associated with lower proinflammatory cytokine levels in patients with HNSCC.


Asunto(s)
Biomarcadores de Tumor/sangre , Carcinoma de Células Escamosas/sangre , Citocinas/sangre , Dieta , Neoplasias de Cabeza y Cuello/sangre , Adulto , Anciano , Anciano de 80 o más Años , Estudios Transversales , Femenino , Humanos , Mediadores de Inflamación/sangre , Masculino , Persona de Mediana Edad , Análisis Multivariante , Oportunidad Relativa , Carcinoma de Células Escamosas de Cabeza y Cuello
16.
Stat Med ; 33(2): 257-74, 2014 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-23824930

RESUMEN

For patients who were previously treated for prostate cancer, salvage hormone therapy is frequently given when the longitudinal marker prostate-specific antigen begins to rise during follow-up. Because the treatment is given by indication, estimating the effect of the hormone therapy is challenging. In a previous paper we described two methods for estimating the treatment effect, called two-stage and sequential stratification. The two-stage method involved modeling the longitudinal and survival data. The sequential stratification method involves contrasts within matched sets of people, where each matched set includes people who did and did not receive hormone therapy. In this paper, we evaluate the properties of these two methods and compare and contrast them with the marginal structural model methodology. The marginal structural model methodology involves a weighted survival analysis, where the weights are derived from models for the time of hormone therapy. We highlight the different conditional and marginal interpretations of the quantities being estimated by the three methods. Using simulations that mimic the prostate cancer setting, we evaluate bias, efficiency, and accuracy of estimated standard errors and robustness to modeling assumptions. The results show differences between the methods in terms of the quantities being estimated and in efficiency. We also demonstrate how the results of a randomized trial of salvage hormone therapy are strongly influenced by the design of the study and discuss how the findings from using the three methodologies can be used to infer the results of a trial.


Asunto(s)
Interpretación Estadística de Datos , Modelos Estadísticos , Antígeno Prostático Específico/sangre , Neoplasias de la Próstata/patología , Ensayos Clínicos Controlados Aleatorios como Asunto/métodos , Terapia Recuperativa/métodos , Simulación por Computador , Humanos , Masculino , Recurrencia Local de Neoplasia , Neoplasias de la Próstata/tratamiento farmacológico , Terapia Recuperativa/normas , Resultado del Tratamiento
17.
Stat Probab Lett ; 93: 126-133, 2014 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-25071299

RESUMEN

In many biomedical studies, identifying effects of covariate interactions on survival is a major goal. Important examples are treatment-subgroup interactions in clinical trials, and gene-gene or gene-environment interactions in genomic studies. A common problem when implementing a variable selection algorithm in such settings is the requirement that the model must satisfy the strong heredity constraint, wherein an interaction may be included in the model only if the interaction's component variables are included as main effects. We propose a modified Lasso method for the Cox regression model that adaptively selects important single covariates and pairwise interactions while enforcing the strong heredity constraint. The proposed method is based on a modified log partial likelihood including two adaptively weighted penalties, one for main effects and one for interactions. A two-dimensional tuning parameter for the penalties is determined by generalized cross-validation. Asymptotic properties are established, including consistency and rate of convergence, and it is shown that the proposed selection procedure has oracle properties, given proper choice of regularization parameters. Simulations illustrate that the proposed method performs reliably across a range of different scenarios.

18.
Subst Use Addctn J ; : 29767342241261890, 2024 Jun 22.
Artículo en Inglés | MEDLINE | ID: mdl-38907675

RESUMEN

Traditional methadone treatment (MT) for opioid use disorder (OUD) fails to systematically address the physical pain, emotion dysregulation, and reward processing deficits that co-occur with OUD, and novel interventions that address these issues are needed to improve MT outcomes. Mindfulness-Oriented Recovery Enhancement (MORE) remediates the hedonic dysregulation in brain reward systems that is associated with OUD. Our pilot and phase 2 randomized controlled trials of MORE were the first to demonstrate MORE's feasibility, acceptability, and efficacy as delivered in MT clinics; MORE significantly reduced drug use (eg, benzodiazepines, barbiturates, cocaine, marijuana, opioids, and other drugs), craving, depression, anxiety, and pain among people with OUD. However, uptake of novel, efficacious interventions like MORE may be slow in MT because time and resources are often limited. Therefore, to best address potential implementation issues and to optimize future MORE implementation and dissemination, in this study, we will utilize a Type 2, Hybrid Implementation-Effectiveness study design. We will not only evaluate MORE's effectiveness but also assess barriers and facilitators to integrating MORE into MT. MT clinicians will receive training in (1) a higher intensity MORE implementation strategy consisting of training in the full MORE treatment manual or (2) a minimal intensity implementation strategy consisting of a simple, scripted mindfulness practice (SMP) extracted from the MORE treatment manual with minimal training. We aim to: (1) using a Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) framework, examine barriers and facilitators to implementation of MORE and SMP in MT, and evaluate strategies for optimizing training, fidelity, and engagement, (2) optimize existing MORE and SMP training and implementation toolkits, including adaptable resources that can accelerate the translation of evidence into practice, and (3) compared to usual MT, evaluate the relative effectiveness of MORE plus MT or SMP plus MT (N = 450).

19.
Stat Methods Med Res ; 33(5): 794-806, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38502008

RESUMEN

Observational data (e.g. electronic health records) has become increasingly important in evidence-based research on dynamic treatment regimes, which tailor treatments over time to patients based on their characteristics and evolving clinical history. It is of great interest for clinicians and statisticians to identify an optimal dynamic treatment regime that can produce the best expected clinical outcome for each individual and thus maximize the treatment benefit over the population. Observational data impose various challenges for using statistical tools to estimate optimal dynamic treatment regimes. Notably, the task becomes more sophisticated when the clinical outcome of primary interest is time-to-event. Here, we propose a matching-based machine learning method to identify the optimal dynamic treatment regime with time-to-event outcomes subject to right-censoring using electronic health record data. In contrast to the established inverse probability weighting-based dynamic treatment regime methods, our proposed approach provides better protection against model misspecification and extreme weights in the context of treatment sequences, effectively addressing a prevalent challenge in the longitudinal analysis of electronic health record data. In simulations, the proposed method demonstrates robust performance across a range of scenarios. In addition, we illustrate the method with an application to estimate optimal dynamic treatment regimes for patients with advanced non-small cell lung cancer using a real-world, nationwide electronic health record database from Flatiron Health.


Asunto(s)
Registros Electrónicos de Salud , Aprendizaje Automático , Humanos , Registros Electrónicos de Salud/estadística & datos numéricos , Modelos Estadísticos , Neoplasias Pulmonares/tratamiento farmacológico , Resultado del Tratamiento , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico
20.
Clin J Am Soc Nephrol ; 19(5): 620-627, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38262377

RESUMEN

BACKGROUND: In a post hoc analysis, we examined whether postrandomization diuretics use can explain and/or mediate the beneficial effects of intensive systolic BP lowering on cardiovascular disease and all-cause mortality in the Systolic Blood Pressure Intervention Trial (SPRINT). METHODS: SPRINT was a randomized, controlled trial of 9361 participants comparing the effects of intensive (systolic BP target <120 mm Hg) versus standard (systolic BP target <140 mm Hg) BP control on a primary composite cardiovascular end point in participants aged 50 years or older with systolic BP of 130-180 mm Hg. In time-varying multivariable Cox analyses, we assessed hazard ratios (HRs) of cardiovascular end points and all-cause mortality in participants on thiazide type, loop and/or potassium (K) sparing, or no diuretics. We also conducted mediation analysis to formally assess the role of diuretics in the effects of intensive systolic BP lowering. RESULTS: At baseline, diuretics were prescribed in 46% and 48% of participants in standard and intensive systolic BP-lowering groups, respectively, and in 46% and 74% in the corresponding groups during the trial. The lower risk of cardiovascular end points in the intensive group (HR, 0.75; 95% confidence interval [CI], 0.64 to 0.89) persisted after adjustment for postrandomization time-varying diuretics use (HR, 0.74; 95% CI, 0.62 to 0.89). Across the entire study population, time-varying diuretics use was not associated with cardiovascular end points (compared with no diuretics, HR for thiazide type, 0.89; 95% CI, 0.73 to 1.10, and loop/K sparing, 1.29; 95% CI, 0.97 to 1.73). However, thiazide-type diuretics were associated with lower risk of cardiovascular end points in the intensive (HR, 0.62; 95% CI, 0.46 to 0.85) but not in the standard (HR, 1.07; 95% CI, 0.82 to 1.39) group. In mediation analysis, HRs for total effect, direct effect (not mediated through diuretics use), and indirect effect (mediated through diuretics) of the intervention on cardiovascular end points were 0.66 (95% CI, 0.54 to 0.79), 0.67 (95% CI, 0.54 to 0.81), and 0.98 (95% CI, 0.88 to 1.10), respectively. The results were largely similar for all-cause mortality. CONCLUSIONS: The favorable effects of intensive systolic BP lowering on cardiovascular end points and all-cause mortality in SPRINT were independent of and not mediated by time-varying diuretics use. However, thiazide-type diuretics use associated with benefit if intensive systolic BP lowering was targeted.


Asunto(s)
Antihipertensivos , Presión Sanguínea , Enfermedades Cardiovasculares , Diuréticos , Hipertensión , Humanos , Masculino , Femenino , Persona de Mediana Edad , Anciano , Presión Sanguínea/efectos de los fármacos , Hipertensión/tratamiento farmacológico , Hipertensión/mortalidad , Hipertensión/fisiopatología , Antihipertensivos/uso terapéutico , Enfermedades Cardiovasculares/mortalidad , Enfermedades Cardiovasculares/prevención & control , Diuréticos/uso terapéutico , Inhibidores de los Simportadores del Cloruro de Sodio/uso terapéutico , Inhibidores del Simportador de Cloruro Sódico y Cloruro Potásico/uso terapéutico , Inhibidores del Simportador de Cloruro Sódico y Cloruro Potásico/efectos adversos , Sístole , Modelos de Riesgos Proporcionales , Resultado del Tratamiento , Factores de Tiempo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA