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1.
Biometrics ; 80(1)2024 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-38393335

RESUMO

Longitudinal studies are often subject to missing data. The recent guidance from regulatory agencies, such as the ICH E9(R1) addendum addresses the importance of defining a treatment effect estimand with the consideration of intercurrent events. Jump-to-reference (J2R) is one classical control-based scenario for the treatment effect evaluation, where the participants in the treatment group after intercurrent events are assumed to have the same disease progress as those with identical covariates in the control group. We establish new estimators to assess the average treatment effect based on a proposed potential outcomes framework under J2R. Various identification formulas are constructed, motivating estimators that rely on different parts of the observed data distribution. Moreover, we obtain a novel estimator inspired by the efficient influence function, with multiple robustness in the sense that it achieves n1/2-consistency if any pairs of multiple nuisance functions are correctly specified, or if the nuisance functions converge at a rate not slower than n-1/4 when using flexible modeling approaches. The finite-sample performance of the proposed estimators is validated in simulation studies and an antidepressant clinical trial.


Assuntos
Antidepressivos , Modelos Estatísticos , Humanos , Simulação por Computador , Estudos Longitudinais , Projetos de Pesquisa
2.
Nanotechnology ; 35(37)2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38857588

RESUMO

The development of electrochemical energy storage devices has a decisive impact on clean renewable energy. Herein, novel ultrafast rechargeable hybrid sodium dual-ion capacitors (HSDICs) were designed by using ultrathin carbon film (UCF) as the cathode material. The UCF is synthesized by a simple low temperature catalytic route followed by an acid leaching process. UCF owns a large adsorption interface and number of additional active sites, which is due to the nitrogen doping. In addition, there exists several short-range order carbons on the surface of UCF, which are beneficial for anionic storage. An ultrafast rechargeable remarkable performance, remarkable anion hybrid storage capability and outstanding structure stability is fully tapped employing UCF as cathode for HSDICs. The electrochemical performance of UCF in a half-cell system at the operating voltage between 1.0 and 4.8 V, achieving an admirable specific discharge capacity of 358.52 mAh·g-1at 500 mA·g-1, and a high capacity retention ratio of 98.42% after cycling 2500 times at 1000 mA·g-1, respectively. Besides, with the support ofex-situTEM and EDS mapping, the structural stability principle and anionic hybrid storage mechanism of UCF electrode are investigated in depth. In the full-cell system, HSDICs with the UCF as cathode and hard carbon as anode also presents a super-long cycle stability (80.62% capacity retention ratio after cycling 1300 times at 1000 mA·g-1).

3.
Pharm Stat ; 2024 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-39415314

RESUMO

In covariate-adaptive or response-adaptive randomization, the treatment assignment and outcome can be correlated. Under this situation, the re-randomization test is a straightforward and attractive method to provide valid statistical inferences. In this paper, we investigate the number of repetitions in tests. This is motivated by a group sequential design in clinical trials, where the nominal significance bound can be very small at an interim analysis. Accordingly, re-randomization tests lead to a very large number of required repetitions, which may be computationally intractable. To reduce the number of repetitions, we propose an adaptive procedure and compare it with multiple approaches under predefined criteria. Monte Carlo simulations are conducted to show the performance of different approaches in a limited sample size. We also suggest strategies to reduce total computation time and provide practical guidance in preparing, executing, and reporting before and after data are unblinded at an interim analysis, so one can complete the computation within a reasonable time frame.

4.
Biometrics ; 79(1): 230-240, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-34453313

RESUMO

Censored survival data are common in clinical trial studies. We propose a unified framework for sensitivity analysis to censoring at random in survival data using multiple imputation and martingale, called SMIM. The proposed framework adopts the δ-adjusted and control-based models, indexed by the sensitivity parameter, entailing censoring at random and a wide collection of censoring not at random assumptions. Also, it targets a broad class of treatment effect estimands defined as functionals of treatment-specific survival functions, taking into account missing data due to censoring. Multiple imputation facilitates the use of simple full-sample estimation; however, the standard Rubin's combining rule may overestimate the variance for inference in the sensitivity analysis framework. We decompose the multiple imputation estimator into a martingale series based on the sequential construction of the estimator and propose the wild bootstrap inference by resampling the martingale series. The new bootstrap inference has a theoretical guarantee for consistency and is computationally efficient compared to the nonparametric bootstrap counterpart. We evaluate the finite-sample performance of the proposed SMIM through simulation and an application on an HIV clinical trial.


Assuntos
Modelos Estatísticos , Projetos de Pesquisa , Simulação por Computador , Análise de Sobrevida
5.
Clin Trials ; 20(1): 89-92, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36169229

RESUMO

BACKGROUND: In clinical trial development, it is a critical step to submit applications, amendments, supplements, and reports on medicinal products to regulatory agencies. The electronic common technical document is the standard format to enable worldwide regulatory submission. There is a growing trend of using R for clinical trial analysis and reporting as part of regulatory submissions, where R functions, analysis scripts, analysis results, and all proprietary code dependencies are required to be included. One unmet and significant gap is the lack of tools, guidance, and publicly available examples to prepare submission R programs following the electronic common technical document specification. METHODS: We introduce a simple and sufficient R package, pkglite, to convert analysis scripts and associated proprietary dependency R packages into a compact, text-based file, which makes the submission document self-contained, easy to restore, transfer, review, and submit following the electronic common technical document specification and regulatory guidelines (e.g. the study data technical conformance guide from the US Food and Drug Administration). The pkglite R package is published on Comprehensive R Archive Network and developed on GitHub. RESULTS: As a tool, pkglite can pack and unpack multiple R packages with their dependencies to facilitate the reproduction and make it an off-the-shelf tool for both sponsors and reviewers. As a grammar, pkglite provides an explicit trace of the packing scope using the concept of file specifications. As a standard, pkglite offers an open file format to represent and exchange R packages as a text file. We use a mock-up example to demonstrate the workflow of using pkglite to prepare submission programs following the electronic common technical document specification. CONCLUSION: pkglite and the proposed workflow enable the sponsor to submit well-organized R scripts following the electronic common technical document specification. The workflow has been used in the first publicly available R-based submission to the US Food and Drug Administration by the R Consortium R submission working group (https://www.r-consortium.org/blog/2022/03/16/update-successful-r-based-test-package-submitted-to-fda).


Assuntos
Eletrônica , Estados Unidos , Humanos , United States Food and Drug Administration
6.
BMC Musculoskelet Disord ; 24(1): 722, 2023 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-37697343

RESUMO

BACKGROUND: There are some cases of Klippel-Feil syndrome with spinal cord injury in clinical work. However, there is no literature report on Brown-Sequard syndrome after trauma. We report a case of Brown-Sequard syndrome following minor trauma in a patient with KFS type III. Her Brown-Sequard syndrome is caused by Klippel-Feil syndrome. CASE PRESENTATION: We found a 38-year-old female patient with KFS in our clinical work. She was unconscious on the spot following a minor traumatic episode. After treatment, her whole body was numb and limb activity was limited. Half an hour later, she felt numb and weak in the right limb and weak in the left limb. She had no previous hypertension, diabetes, or coronary heart disease. After one-month treatment of medication, hyperbaric oxygen, rehabilitation, and acupuncture in our hospital, her muscle strength partially recovered, but the treatment effect was still not satisfactory. Then, she underwent surgical treatment and postoperative comprehensive treatment, and rehabilitation training. She was able to take care of herself with assistance, and her condition improved from grade B to grade D according to the ASIA (ASIA Impairment Scale) classification. CONCLUSION: KFS, also known as short neck deformity, is a kind of congenital deformity characterized by impaired formation and faulty segmentation of the cervical spine, often associated with abnormalities of other organs. The cervical deformity in patients with KFS can alter the overall mechanical activity of the spine, as well as the compensatory properties of the spine for decelerating and rotatory forces, thus increasing the chance of spinal cord injury (SCI) following trauma. Many mechanisms can make patients more susceptible to injury. Increased range of motion of the segment adjacent to the fused vertebral body may lead to slippage of the adjacent vertebral body and altered disc stress, as well as cervical instability. SCI can result in complete or incomplete impairment of motor, sensory and autonomic nervous functions below the level of lesion. This woman presented with symptoms of BSS, a rare neurological disorder with incomplete SCI. Judging from the woman's symptoms, we concluded that previously she had KFS, which resulted in SCI without fracture and dislocation following minor trauma, with partial BSS. After the comprehensive treatment of surgery, hyperbaric oxygen, rehabilitation therapy, and neurotrophic drugs, two years later, we found her symptoms significantly improved, with ASIA Impairment Scale from grade B to grade D, and her ability to perform activities of daily living with aids.


Assuntos
Síndrome de Brown-Séquard , Síndrome de Klippel-Feil , Traumatismos da Medula Espinal , Humanos , Feminino , Adulto , Síndrome de Klippel-Feil/complicações , Síndrome de Brown-Séquard/diagnóstico por imagem , Síndrome de Brown-Séquard/etiologia , Síndrome de Brown-Séquard/cirurgia , Atividades Cotidianas , Vértebras Cervicais/diagnóstico por imagem , Vértebras Cervicais/cirurgia
7.
Gen Physiol Biophys ; 42(3): 285-295, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37098737

RESUMO

Sevoflurane (Sev) is a wildly used volatile anesthetic agent that induces neurotoxicity. Long non-coding RNAs (lncRNAs) have been demonstrated to be involved in Sev-induced neuronal injury. Here, we investigated the role of NF-kappaB-interacting lncRNA (NKILA) in Sev-treated human cortical neurons (HCN). From RT-qPCR, Sev dose-dependently increased HCN NKILA transcript expression. Neurotoxicity of Sev was detected using MTT, flow cytometry, Western blotting, and inflammatory mediator assays. Consequently, Sev reduced HCN viability and levels of Bcl-2, SOD, and GSH in HCN, and promoted HCN apoptosis rate and levels of cleaved-caspase-3, Bax, MDA, TNF-α, IL-6, and IL-1ß. Silencing NKILA suppressed Sev-induced above effects. DIANA and starbase databases predicted the potential target relationship between miR-205-5p and NKILA or embryonic lethal abnormal vision-like 1 (ELAVL1); dual-luciferase and RIP confirmed these interactions. NKILA could increase ELAVL1 expression by regulating miR-205-5p. miR-205-5p overexpression and ELAVL1 knockdown could mimic effects of NKILA silencing in Sev-induced HCN. Deleting miR-205-5p and restoring ELAVL1 respectively abolished the neuroprotective effect of NKILA knockdown and miR-205-5p upregulation under Sev anesthesia. In conclusion, Sev induced neuronal cell apoptosis, inflammatory response and oxidative stress through NKILA/miR- 205-5p/ELAVL1 axis and caspase-3 and Bax/Bcl-2 pathway. Inhibiting NKILA might be a potential therapeutic strategy for Sev neurotoxicity.


Assuntos
MicroRNAs , RNA Longo não Codificante , Humanos , NF-kappa B/metabolismo , Sevoflurano , RNA Longo não Codificante/genética , Caspase 3/metabolismo , Proteína X Associada a bcl-2/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Apoptose/genética , Neurônios/metabolismo , Proteína Semelhante a ELAV 1
8.
Malar J ; 21(1): 91, 2022 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-35300704

RESUMO

BACKGROUND: Few studies have been conducted to investigate the distribution of mosquito vectors and the population structure of secondary vectors in the border region of Cambodia-Laos. The aim of this work was to study the mosquito diversity and molecular phylogeny of secondary vectors, i.e., Anopheles nivipes in this area. METHODS: 1440 adult mosquitoes were trapped in the Cambodia-Laos border. mtDNA-COII were amplified and sequenced from 53 An. nivipes DNA samples. Together with COII sequences deposited in GenBank, a total of 86 COII sequences were used for examining population variations, genetic differentiation, spatial population structure, population expansion, and gene flow patterns. RESULTS: The adult mosquitoes were classified into 5 genera and 27 species in this border region. The predominant genera were Culex (60.07%, 865/1440) and Anopheles (31.25%, 450/1440), and the major Anopheles species were An. nivipes (73.56%, 331/450) and Anopheles maculatus (14.22%, 64/450). Based on sequences analysis of COII, a high level of genetic differentiation was reported in two Northwest India (Cheema and Bathinda, Punjab) and Cambodia-Laos (Siem Pang, Stung treng) populations (FST = 0.97824, 0.97343, P < 0.05), as well as lower gene flow (Nm = 0.01112, 0.01365) in the An. nivipes populations. Phylogenetic analysis and SAMOVA revealed a gene barrier restricting gene flow among three An. nivipes populations. Mantel test suggested a significant correlation between geography and gene distance in all An. nivipes populations (Z = 44,983.1865, r = 0.5575, P = 0.0070). Neutrality test and Mismatch distribution revealed a recent population expansion of An. nivipes in the Cambodia-Laos population. CONCLUSIONS: Anopheles nivipes was one of the major Anopheles species in the Cambodia-Laos border. Based on sequences analysis of COII, a genetic barrier between Cambodia-Laos and two Indian populations was found, and a recent population expanding or selecting of An. nivipes occurred in the Cambodia-Laos population, suggesting that COII might be an effective marker for describing the molecular phylogeny of An. nivipes. Further investigation and continuous surveillance of An. nivipes are warranted in this region.


Assuntos
Anopheles , Animais , Anopheles/genética , Camboja , DNA Mitocondrial/genética , Laos , Filogenia
9.
Pediatr Diabetes ; 23(2): 173-182, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34779087

RESUMO

OBJECTIVE: To assess the efficacy and safety of DPP-4 inhibition with sitagliptin in youth with type 2 diabetes (T2D). STUDY DESIGN: This was a 54-week, double-blind, randomized, controlled clinical trial evaluating the safety and efficacy of DPP-4 inhibition with sitagliptin 100 mg once daily as initial oral therapy in youth with T2D. The 190 participants, aged 10-17 years, had HbA1c 6.5%-10% (7.0%-10% if on insulin). All were negative for pancreatic autoantibodies and overweight/obese at screening or diagnosis. The trial was placebo controlled for the first 20 weeks, after which metformin replaced placebo. The primary efficacy endpoint was change from baseline in HbA1c at Week 20. RESULTS: Treatment groups were well balanced at baseline (mean ± SD HbA1c = 7.5% ± 1.0, BMI percentile = 97.1% ± 6.8, age = 14.0 years ± 2.0 [57.4% <15], 60.5% female). At Week 20, least squares mean changes from baseline in HbA1c were -0.01% (sitagliptin) and 0.18% (placebo); between-group difference (95% CI) = -0.19% (-0.68, 0.30), p = 0.448. At Week 54, the changes in HbA1c were 0.45% (sitagliptin) and -0.11 (placebo/metformin). There were no notable between-group differences in the adverse event profiles through Week 54. CONCLUSIONS: DPP-4 inhibition with sitagliptin did not provide significant improvement in glycemic control. In this study, sitagliptin was generally well tolerated with a safety profile similar to that reported in adults. (ClinicalTrials.gov: NCT01485614; EudraCT: 2011-002528-42).


Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Segurança do Paciente/normas , Fosfato de Sitagliptina/farmacologia , Administração Oral , Adolescente , Glicemia/análise , Criança , Diabetes Mellitus Tipo 2/fisiopatologia , Método Duplo-Cego , Quimioterapia Combinada/métodos , Quimioterapia Combinada/estatística & dados numéricos , Feminino , Hemoglobinas Glicadas/análise , Humanos , Hipoglicemiantes/farmacologia , Hipoglicemiantes/uso terapêutico , Masculino , Metformina/farmacologia , Metformina/uso terapêutico , Segurança do Paciente/estatística & dados numéricos , Fosfato de Sitagliptina/uso terapêutico , Resultado do Tratamento
10.
Pediatr Diabetes ; 23(2): 183-193, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34779103

RESUMO

OBJECTIVE: To assess the efficacy and safety of sitagliptin in youth with type 2 diabetes (T2D) inadequately controlled with metformin ± insulin. STUDY DESIGN: Data were pooled from two 54-week, double-blind, randomized, placebo-controlled studies of sitagliptin 100 mg daily or placebo added onto treatment of 10- to 17-year-old youth with T2D and inadequate glycemic control on metformin ± insulin. Participants (N = 220 randomized and treated) had HbA1c 6.5%-10% (7.0%-10% if on insulin), were overweight/obese at screening or diagnosis and negative for pancreatic autoantibodies. The primary endpoint was change from baseline in HbA1c at Week 20. RESULTS: Treatment groups were well balanced at baseline (mean HbA1c = 8.0%, BMI = 30.9 kg/m2 , age = 14.4 years [44.5% <15], 65.9% female). The dose of background metformin was >1500 mg/day for 71.8% of participants; 15.0% of participants were on insulin therapy. At Week 20, LS mean changes from baseline (95% CI) in HbA1c for sitagliptin/metformin and placebo/metformin were -0.58% (-0.94, -0.22) and -0.09% (-0.43, 0.26), respectively; difference = -0.49% (-0.90, -0.09), p = 0.018; at Week 54 the LS mean (95% CI) changes were 0.35% (-0.48, 1.19) and 0.73% (-0.08, 1.54), respectively. No meaningful differences between the adverse event profiles of the treatment groups emerged through Week 54. CONCLUSIONS: These results do not suggest that addition of sitagliptin to metformin provides durable improvement in glycemic control in youth with T2D. In this study, sitagliptin was generally well tolerated with a safety profile similar to that reported in adults. (ClinicalTrials.gov: NCT01472367, NCT01760447; EudraCT: 2011-002529-23/2014-003583-20, 2012-004035-23).


Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Segurança do Paciente/normas , Fosfato de Sitagliptina/farmacologia , Administração Oral , Adolescente , Glicemia/análise , Criança , Diabetes Mellitus Tipo 2/fisiopatologia , Método Duplo-Cego , Quimioterapia Combinada/métodos , Quimioterapia Combinada/estatística & dados numéricos , Feminino , Hemoglobinas Glicadas/análise , Humanos , Hipoglicemiantes/farmacologia , Hipoglicemiantes/uso terapêutico , Masculino , Metformina/farmacologia , Metformina/uso terapêutico , Segurança do Paciente/estatística & dados numéricos , Fosfato de Sitagliptina/uso terapêutico , Resultado do Tratamento
11.
BMC Musculoskelet Disord ; 23(1): 206, 2022 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-35246101

RESUMO

BACKGROUND: Little is known about the biomechanical performance of different internal fixations in oblique lumbar interbody fusion (OLIF). Here, finite element (FE) analysis was used to describe the biomechanics of various internal fixations and compare and explore the stability of each fixation. METHODS: CT scans of a patient with lumbar degenerative disease were performed, and the l3-S1 model was constructed using relevant software. The other five FE models were constructed by simulating the model operation and adding different related implants, including (1) an intact model, (2) a stand-alone (SA) model with no instrument, (3) a unilateral pedicle screw model (UPS), (4) a unilateral pedicle screw contralateral translaminar facet screw model (UPS-CTFS), (5) a bilateral pedicle screw (BPS) model, and (6) a cortical bone trajectory screw model (CBT). Various motion loads were set by FE software to simulate lumbar vertebral activity. The software was also used to extract the range of motion (ROM) of the surgical segment, CAGE and fixation stress in the different models. RESULTS: The SA group had the greatest ROM and CAGE stress. The ROM of the BPS and UPS-CTFS was not significantly different among motion loadings. Compared with the other three models, the BPS model had lower internal fixation stress among loading conditions, and the CBT screw internal fixation had the highest stress among loads. CONCLUSIONS: The BPS model provided the best biomechanical stability for OLIF. The SA model was relatively less stable. The UPS-CTFS group had reduced ROM in the fusion segments, but the stresses on the internal fixation and CAGE were relatively higher in the than in the BPS group; the CBT group had a lower flexion and extension ROM and higher rotation and lateral flexion ROM than the BPS group. The stability of the CBT group was poorer than that of the BPS and LPS-CTFS groups. The CAGE and internal fixation stress was greater in the CBT group.


Assuntos
Parafusos Pediculares , Fusão Vertebral , Fenômenos Biomecânicos , Análise de Elementos Finitos , Humanos , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/cirurgia , Amplitude de Movimento Articular
12.
Opt Express ; 29(12): 17951-17961, 2021 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-34154066

RESUMO

High efficiency and accuracy phase gratings are of crucial importance for large format heterodyne array receivers at terahertz frequencies. Here, by developing a design approach that can create gratings with arbitrary two-dimensional diffraction distributions, we have realized a reflective metallic phase grating that generates 2×2 diffraction beams at 0.85 THz. The measured total power efficiency of the diffraction beam pattern is 81.9%, which demonstrates at least 17% improvement in efficiency compared with the standard pseudo-2D Fourier phase grating. In addition, we report the realization of up to 10×10 diffraction beam two-dimensional phase grating designs at terahertz wavelengths, using an adaptation of the Gerchberg-Saxton (GS) scheme known as the Mixed-Region-Amplitude-Freedom algorithm. Rigorous full wave simulation proves the efficiency and accuracy of the design, which overcomes the inaccurate intensity of the beam distribution drawbacks originated from the standard GS algorithm. The results pave the way for the development of large-pixel terahertz multi-beam heterodyne receivers.

13.
Xenobiotica ; 51(12): 1389-1399, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34806938

RESUMO

1. 8-methylene-tert-butylamine-3',5,7-trihydroxy-4'-methoxyflavanone (MTBH), a novel hesperidin derivative, has potential in the prevention of hepatic disease, however, its effects on cytochrome P450 isoforms (CYP450s) remains unexplored. The purpose was to investigate the effects of MTBH on the mRNA, protein levels, and activities of six CYP450s (1A2, 2C11/9, 2D2/6, 3A1/4, 2C13/19, and 2E1) in vitro and in vivo.2. In vitro study, rat and human liver microsomes were adopted to elucidate the inhibitory effect of MTBH on six CYP450s using probe drugs. In vivo study, Sprague-Dawley male rats were treated with MTBH (25, 50, or 100 mg/kg for 28 consecutive days), phenobarbital (80 mg/kg for 12 consecutive days), or 0.5% CMC-Na solution (control group) by intragastric administration, then, the mRNA, protein levels and activities of liver CYP450s were analysed by real-time PCR, western blotting and probe-drug incubation systems, respectively.3. The in vitro study indicated that MTBH inhibits the activities of CYP3A1/4 and CYP2E1 in rat and human liver microsomes. In vivo data showed that MTBH inhibits mRNA, protein levels, and activities of CYP3A1 and CYP2E1 in medium- and high-dose MTBH groups.4. MTBH has the potential to cause drug-drug interactions when co-administered with drugs that are metabolised by CYP3A1/4 and CYP2E1.


Assuntos
Hesperidina , Animais , Cromatografia Líquida de Alta Pressão , Sistema Enzimático do Citocromo P-450 , Hesperidina/farmacologia , Fígado , Masculino , Microssomos Hepáticos , Isoformas de Proteínas , Ratos , Ratos Sprague-Dawley , Espectrometria de Massas em Tandem
14.
Lifetime Data Anal ; 27(2): 195-215, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33507457

RESUMO

With recent advancement in cancer screening and treatment, many patients with cancers are identified at early stage and clinically cured. Importantly, uncured patients should be treated timely before the cancer progresses to advanced stages for which therapeutic options are rather limited. It is also crucial to identify uncured subjects among patients with early-stage cancers for clinical trials to develop effective adjuvant therapies. Thus, it is of interest to develop statistical predictive models with as high accuracy as possible in predicting the latent cure status. The receiver operating characteristic curve (ROC) and the area under the ROC curve (AUC) are among the most widely used statistical metrics for assessing predictive accuracy or discriminatory power for a dichotomous outcome (cured/uncured). Yet the conventional AUC cannot be directly used due to incompletely observed cure status. In this article, we proposed new estimates of the ROC curve and its AUC for predicting latent cure status in Cox proportional hazards (PH) cure models and transformation cure models. We developed explicit formulas to estimate sensitivity, specificity, the ROC and its AUC without requiring to know the patient cure status. We also developed EM type estimates to approximate sensitivity, specificity, ROC and AUC conditional on observed data. Numerical studies were used to assess their finite-sample performance of the proposed methods. Both methods are consistent and have similar efficiency as shown in our numerical studies. A melanoma dataset was used to demonstrate the utility of the proposed estimates of the ROC curve for the latent cure status. We also have developed an [Formula: see text] package called [Formula: see text] to efficiently compute the proposed estimates.


Assuntos
Modelos Estatísticos , Neoplasias , Área Sob a Curva , Humanos , Modelos de Riscos Proporcionais , Curva ROC
15.
Stat Med ; 39(20): 2671-2684, 2020 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-32394520

RESUMO

Assessing and comparing the performance of correlated predictive scores are of current interest in precision medicine. Given the limitations of available theoretical approaches for assessing and comparing the predictive accuracy, numerical methods are highly desired which, however, have not been systematically developed due to technical challenges. The main challenges include the lack of a general strategy on effectively simulating many kinds of correlated predictive scores each with some given level of predictive accuracy in either concordance index or the area under a receiver operating characteristic curve area under the curves (AUC). To fill in this important knowledge gap, this paper is to provide a general copula-based numeric framework for assessing and comparing predictive performance of correlated predictive or risk scores. The new algorithms are designed to effectively simulate correlated predictive scores with given levels of predictive accuracy as measured in terms of concordance indices or time-dependent AUC for predicting survival outcomes. The copula-based numerical strategy is convenient for numerically evaluating and comparing multiple measures of predictive accuracy of correlated risk scores and for investigating finite-sample properties of test statistics and confidence intervals as well as assessing for optimism of given performance measures using cross-validation or bootstrap.


Assuntos
Algoritmos , Medicina de Precisão , Humanos , Valor Preditivo dos Testes , Curva ROC , Fatores de Risco
16.
Health Qual Life Outcomes ; 18(1): 349, 2020 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-33092600

RESUMO

BACKGROUND: The aim of this study is to investigate the reliability, validity, and responsiveness of JOACMEQ for CSM patients in mainland China. METHODS: A retrospective review was performed on 91 patients with CSM in our hospital from March 2015 to June 2015. Patients completed the JOACMEQ, the mJOA and the SF-36 questionnaires during the process. Cronbach's α was used to evaluate the internal consistency reliability, and test-retest reliability was checked. An exploratory factor analysis was used to determine the correlations among the JOACMEQ questions and the construct validity. The concurrent validity was assessed by Spearman correlation coefficient. The internal responsiveness was determined by effect sizes and standardized response means. External responsiveness was determined by the area under the receiver operating characteristic curve on the basis of the Youden Index. RESULTS: The mean age of patients was 57.61 years old. The mean follow-up was 24 months. JOACMEQ showed a good internal consistency (Cronbach's α, 0.897). Test-retest reliability showing good result (Pearson's correlation, 0.695-0.905). Our data were amenable to factor analysis (KMO = 0.816, Bartlett's test, χ2(45) = 1199.99, p < 0.001), and five factors above 1 were strongly loaded and clustered for each of the five factors. Comparing the scales preoperative to those 2 years postoperative, the average scores of the subscales all increased, and both the ES and SRM showing satisfied responsiveness. In external responsiveness analysis, the recovery rate a appeared to be most responsive to post-operative improvement. CONCLUSIONS: The Simplified Chinese version of JOACMEQ was well-developed with great reliability and sensitive responsiveness. Our study demonstrated that JOACMEQ has content psychometric properties to identify postoperative improvements in CSM patients.


Assuntos
Qualidade de Vida , Compressão da Medula Espinal/psicologia , Inquéritos e Questionários/normas , Adulto , Idoso , Vértebras Cervicais , China , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Estudos Retrospectivos
17.
Biostatistics ; 19(1): 14-26, 2018 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-28481968

RESUMO

Many populations of early-stage cancer patients have non-negligible latent cure fractions that can be modeled using transformation cure models. However, there is a lack of statistical metrics to evaluate prognostic utility of biomarkers in this context due to the challenges associated with unknown cure status and heavy censorship. In this article, we develop general concordance measures as evaluation metrics for the discriminatory accuracy of transformation cure models including the so-called promotion time cure models and mixture cure models. We introduce explicit formulas for the consistent estimates of the concordance measures, and show that their asymptotically normal distributions do not depend on the unknown censoring distribution. The estimates work for both parametric and semiparametric transformation models as well as transformation cure models. Numerical feasibility of the estimates and their robustness to the censoring distributions are illustrated via simulation studies and demonstrated using a melanoma data set.


Assuntos
Modelos Estatísticos , Neoplasias/diagnóstico , Neoplasias/terapia , Avaliação de Resultados em Cuidados de Saúde/estatística & dados numéricos , Humanos , Neoplasias/tratamento farmacológico , Neoplasias/cirurgia
18.
Diabetes Obes Metab ; 21(4): 781-790, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30393950

RESUMO

AIMS: To compare the effects of continuing versus discontinuing sitagliptin when initiating and intensively titrating insulin glargine. MATERIALS AND METHODS: Eligible patients had inadequately controlled type 2 diabetes on metformin (≥1500 mg/d) in combination with a dipeptidyl peptidase-4 (DPP-4) inhibitor and/or a sulphonylurea. Those on metformin + sitagliptin were directly randomized; all others were switched to metformin + sitagliptin (discontinuing other DPP-4 inhibitors and sulphonylureas) and stabilized during a run-in period. At randomization, patients were allocated to continuing sitagliptin or discontinuing sitagliptin, with both groups initiating insulin glargine and titrating to a target fasting glucose of 4.0 to 5.6 mmol/L. RESULTS: A total of 743 participants (mean glycated haemoglobin [HbA1c] 72.6 mmol/mol [8.8%], disease duration 10.8 years), were treated. After 30 weeks, the mean HbA1c and least squares (LS) mean change from baseline in HbA1c were 51.4 mmol/mol (6.85%) and -20.5 mmol/mol (-1.88%) in the sitagliptin group and 56.4 mmol/mol (7.31%) and -15.5 mmol/mol (-1.42%) in the placebo group; the difference in LS mean changes from baseline HbA1c was -5.0 mmol/mol (-0.46%; P < 0.001). The percentage of participants with HbA1c <53 mmol/mol (<7.0%) was higher (54% vs. 35%) and the mean daily insulin dose was lower (53 vs. 61 units) in the sitagliptin group. Despite lower HbA1c, event rates and incidences of hypoglycaemia were not higher in the sitagliptin group. Adverse events overall and changes from baseline in body weight were similar between the two treatment groups. CONCLUSION: When initiating insulin glargine therapy, continuation of sitagliptin, compared with discontinuation, resulted in a clinically meaningful greater reduction in HbA1c without an increase in hypoglycaemia. ClinicalTrials.gov Identifier: NCT02738879.


Assuntos
Desprescrições , Diabetes Mellitus Tipo 2/tratamento farmacológico , Inibidores da Dipeptidil Peptidase IV/uso terapêutico , Hipoglicemiantes/uso terapêutico , Insulina Glargina/uso terapêutico , Metformina/uso terapêutico , Fosfato de Sitagliptina/uso terapêutico , Idoso , Diabetes Mellitus Tipo 2/metabolismo , Método Duplo-Cego , Quimioterapia Combinada , Feminino , Hemoglobinas Glicadas/metabolismo , Humanos , Hipoglicemia/induzido quimicamente , Análise dos Mínimos Quadrados , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
20.
Molecules ; 24(20)2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31614601

RESUMO

To develop new anti-inflammatory agents, a series of 7-O-amide hesperetin derivatives was designed, synthesized and evaluated for anti-inflammatory activity using RAW264.7 cells. All compounds showed inhibitory effect on LPS-induced NO production. Among them, 7-O-(2-(Propylamino)-2-oxoethyl)hesperetin (4d) and 7-O-(2-(Cyclopentylamino)-2-oxoethyl)hesperetin (4k) with hydrophobic side chains exhibited the most potent NO inhibitory activity (IC50 = 19.32 and 16.63 µM, respectively), showing stronger inhibitory effect on the production of pro- inflammatory cytokines tumor necrosis factor (TNF-α), interleukin-6 (IL-6) and interleukin-1ß (IL-1ß) than indomethacin and celecoxib at 10 µM. The structure-activity relationships (SARs) suggested that the 7-O-amide unit was buried in a medium-sized hydrophobic cavity of the bound receptor. Furthermore, compound 4d could also significantly suppress the expression of inducible nitric oxide synthase enzymes (iNOS) and cyclooxygenase-2 (COX-2), through the nuclear factor-kappa B (NF-κB) signaling pathway.


Assuntos
Hesperidina/química , Hesperidina/farmacologia , Inflamação/tratamento farmacológico , Óxido Nítrico/biossíntese , Animais , Celecoxib/farmacologia , Ciclo-Oxigenase 2/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Hesperidina/síntese química , Humanos , Interações Hidrofóbicas e Hidrofílicas/efeitos dos fármacos , Indometacina/farmacologia , Inflamação/metabolismo , Inflamação/patologia , Interleucina-1beta/genética , Interleucina-6/genética , Camundongos , NF-kappa B/genética , Óxido Nítrico/antagonistas & inibidores , Óxido Nítrico Sintase Tipo II/genética , Transdução de Sinais/efeitos dos fármacos , Relação Estrutura-Atividade , Fator de Necrose Tumoral alfa/genética
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