Innovative Thinking on Endpoint Selection in Clinical Trials

ABSTRACT

In clinical trials, selection of appropriate study endpoints is critical for an accurate and reliable evaluation of safety and effectiveness of a test treatment under investigation. In practice, however, there are usually multiple endpoints available for measurement of disease status and/or therapeutic effect of the test treatment under study. For example, in cancer clinical trials, overall survival, response rate, and/or time to disease progression are usually considered as primary clinical endpoints for evaluation of safety and effectiveness of the test treatment under investigation. Once the study endpoints have been selected, sample size required for achieving a desired power is then determined. It, however, should be noted that different study endpoints may result in different sample sizes. In practice, it is usually not clear which study endpoint can best inform the disease status and measure the treatment effect. Moreover, different study endpoints may not translate one another although they may be highly correlated one another. In this article, we intend to develop an innovative endpoint namely therapeutic index based on a utility function to combine and utilize information collected from all study endpoints. Statistical properties and performances of the proposed therapeutic index are evaluated theoretically. A numerical example concerning a cancer clinical trial is given to illustrate the use of the proposed therapeutic index.     

神经源性声带运动障碍与喉神经电生理

声带运动障碍的病因和临床表现复杂多变，涉及多学科，从病因上分为神经源性和非神经源性。对于神经源性声带运动障碍的诊治，首先通过喉镜等检查明确有无声带运动障碍及严重程度，值得注意的是声带纵向张力变化障碍也属于运动障碍的范畴；然后采用喉肌电图（LEMG）检查进行定性分析，在确诊神经源性损伤后，进一步对神经损伤部位进行定位诊断并查找导致神经损伤的病因；同时根据喉部神经电生理评估结果，判断预后。最后综合上述的评估结果制定相应的治疗策略。     

VATS解剖性肺段切除术与肺叶切除术治疗Ⅰa期NSCLC患者的手术情 况及对肺功能影响的比较

目的:探讨电视胸腔镜（VATS）解剖性肺段切除术与肺叶切除术治疗Ia 期非小细胞肺癌（NSCLC）患者的手术情况及对患者肺功能的影响。方法:选取我院手术治疗的Ⅰa期NSCLC患者，收集时间2014年1月至2016年12月，根据术式不同分为两组，均采用VATS手术治疗，A组（54例）患者采用解剖性肺段切除术、B组（60例）采用肺叶切除术治疗，对比两组患者的手术效果及术后肺功能变化。结果:A组患者的手术时间、清扫淋巴结数目与B组比较差异无统计学意义（P>0.05）；A组患者的手术出血量、术后胸腔引流量、术后拔管时间、术后住院时间均显著的低于B组患者（P<0.05）；术前，A组和B组患者的FEV1%、FVC%、MVV%测定值差异无统计学意义（P>0.05），术后3个月复查，A组患者的FEV1%、FVC%、MVV%测定值均显著高于B组患者（P<0.05）；手术后，A组患者的并发症发生率（7.41%）低于B组患者（13.33%），但是差异无统计学意义（P>0.05）。结论:VATS解剖性肺段切除术治疗Ⅰa期NSCLC患者具有手术创伤小、术后恢复快、对患者肺功能影响更小的优势。     

3D-CRT 低剂量区 V5体积的大小对非小细胞肺癌患者肺功能的影响

目的：探讨3D-CRT 低剂量区 V5体积的大小对非小细胞肺癌患者肺功能的影响。方法：收集我院肿瘤科2014年4月～2015年10月收治的46例首次行三维适形放射治疗且顺利完成治疗的非小细胞肺癌患者，对每例患者分别在治疗前以及治疗后的1、3个月进行肺功能检测，分析3D-CRT 低剂量区 V5体积的大小与肺功能变化之间的关系。结果：放疗后1个月的 FEV1％、FVC％值明显高于放疗前且差异均具有显著性。放疗后1个月、3个月的 DLCO％值明显低于放疗前，且放疗前的与放疗后3个月的差异具有显著性；V5≦45％、45％55％三组放疗前后的 FEV1％值和 FVC％值比较差异均不具有显著性。V5≦45％、45％55％三组放疗前后的 DLCO％值均呈逐渐下降趋势，且 V5>55％组的放疗前后 DLCO％值比较差异具有显著性。而 V5≦45％组和45％55％时，DLCO％值降低的趋势更加显著。     

Unconditional Positivity-Preserving and Energy Stable Schemes for a Reduced Poisson-Nernst-Planck System

The Poisson-Nernst-Planck (PNP) system is a widely accepted model for simulation of ionic channels. In this paper, we design, analyze, and numerically validate a second order unconditional positivity-preserving scheme for solving a reduced PNP system, which can well approximate the three dimensional ion channel problem. Positivity of numerical solutions is proven to hold true independent of the size of time steps and the choice of the Poisson solver. The scheme is easy to implement without resorting to any iteration method. Several numerical examples further confirm the positivity-preserving property, and demonstrate the accuracy, efficiency, and robustness of the proposed scheme, as well as the fast approach to steady states.     

Fractal dimension in CT low attenuation areas is predictive of long-term oxygen therapy initiation in COPD patients: Results from two observational cohort studies

BackgroundSome chronic obstructive pulmonary disease (COPD) patients develop hypoxemia with disease progression, with some even requiring long-term oxygen therapy (LTOT). Lung function, especially diffusing capacity, and the annual decline in PaO₂, are reported to be predictive factors of chronic respiratory failure. However, the association between lung morphometry evaluated using computed tomography (CT) images and LTOT initiation is unknown.MethodsWe retrospectively evaluated the relationship between clinical indices, including pulmonary function, body mass index (BMI), and CT parameters, at baseline and LTOT initiation in two prospective COPD cohorts. In the Nara Medical University cohort (n = 76), the low attenuation area (LAA) and its fractal dimension (fractal D) were adapted as the indices for parenchymal destruction in CT images. The association between these CT measurements and LTOT initiation was replicated in the Kyoto University cohort (n = 130).ResultsIn the Nara Medical University cohort, lower BMI (hazard ratio [HR]:0.70, p = 0.006), lower % diffusing capacity (%DLCO) (HR: 0.92, p = 0.006), lower %DLCO/VA (HR, 0.90, p = 0.008), higher RV/TLC (HR, 1.26, p = 0.012), higher LAA% (HR: 1.18, p = 0.001), and lower fractal D (HR: 3.27 × 10^?8, p < 0.001) were associated with LTOT initiation. Multivariate analysis in the Kyoto University cohort confirmed that lower %DLCO and lower fractal D were independently associated with LTOT initiation, whereas LAA% was not.ConclusionFractal D, which is the index for morphometric complexity of LAA in CT analysis, is predictive of LTOT initiation in COPD patients.     

Coupling online control and inhibitory systems in children with Developmental Coordination Disorder: Goal-directed reaching

For children with Developmental Coordination Disorder (DCD), the real-time coupling between frontal executive function and online motor control has not been explored despite reported deficits in each domain. The aim of the present study was to investigate how children with DCD enlist online control under task constraints that compel the need for inhibitory control. A total of 129 school children were sampled from mainstream primary schools. Forty-two children who met research criteria for DCD were compared with 87 typically developing controls on a modified double-jump reaching task. Children within each skill group were divided into three age bands: younger (6–7 years), mid-aged (8–9), and older (10–12). Online control was compared between groups as a function of trial type (non-jump, jump, anti-jump). Overall, results showed that while movement times were similar between skill groups under simple task constraints (non-jump), on perturbation (or jump) trials the DCD group were significantly slower than controls and corrected trajectories later. Critically, the DCD group was further disadvantaged by anti-jump trials where inhibitory control was required; however, this effect reduced with age. While coupling online control and executive systems is not well developed in younger and mid-aged children, there is evidence of age-appropriate coupling in older children. Longitudinal data are needed to clarify this intriguing finding. The theoretical and applied implications of these results are discussed.     

Influence of COMT genotype and affective distractors on the processing of self-generated thought

The catechol-O-methyltransferase (COMT) enzyme is a major determinant of prefrontal dopamine levels. The Val¹⁵⁸Met polymorphism affects COMT enzymatic activity and has been associated with variation in executive function and affective processing. This study investigated the effect of COMT genotype on the flexible modulation of the balance between processing self-generated and processing stimulus-oriented information, in the presence or absence of affective distractors. Analyses included 124 healthy adult participants, who were also assessed on standard working memory (WM) tasks. Relative to Val carriers, Met homozygotes made fewer errors when selecting and manipulating self-generated thoughts. This effect was partly accounted for by an association between COMT genotype and visuospatial WM performance. We also observed a complex interaction between the influence of affective distractors, COMT genotype and sex on task accuracy: male, but not female, participants showed a sensitivity to the affective distractors that was dependent on COMT genotype. This was not accounted for by WM performance. This study provides novel evidence of the role of dopaminergic genetic variation on the ability to select and manipulate self-generated thoughts. The results also suggest sexually dimorphic effects of COMT genotype on the influence of affective distractors on executive function.     

Organic and Inorganic Mercury in Biological Samples of Flouresecent Lamp Industries Workers and Health Risks

Objective The present study aims to investigate the concentrations of Hg and its aspects methyl mercury(Me-Hg) and inorganic mercury(I-Hg) in the biological samples(BSs) of fluorescent lamp industries workers(FLIWs).Methodology Different BSs including red blood cells(RBCs),plasma,urine,hair and nails were collected from the workers exposed to Hg and unexposed persons were selected as control group to measure both the T-Hg concentration as well as its species in different biological samples through quantitative analysis.Health data was collected through questionnaire survey.Results The mean concentrations of T-Hg(31.9 μg/L),Me-Hg(27.7 μg/L),and I-Hg(5.36 μg/L) in RBCs were found significantly(P 0.001) higher among the workers(n = 40) as compared to the control group(n = 40).Similarly the mean Hg concentrations in plasma,urine,hair and nails were also significantly higher among the workers than the control group.The statistical relation between Hg concentration and demographic characteristics observed that workers experience and fish consumption has increased the Hg concentration while age,weight and smoking found no significant effect on Hg concentration in the BSs.Conclusion The study observed that the workers were highly exposed to high concentration of Hg and they are at a high health risk.