Identification of 4‐aryl‐1H‐pyrrole[2,3‐b]pyridine derivatives for the development of new B‐Raf inhibitors

During the last years, a significant interest in the identification of new classes of B‐Raf inhibitors has emerged. In this study, which was conceived within an effort that culminated in the recent report of the first dual inhibitors of B‐Raf and Hsp90, we describe the identification of four compounds based on 4‐aryl‐1H‐pyrrole[2,3‐b]pyridine scaffold as interesting starting points for the development of new B‐Raf inhibitors. Structure–activity relationships and predicted binding modes are discussed. Moreover, the novelty of the newly identified structures with respect to currently known B‐Raf inhibitors was assessed through a ligand‐based dissimilarity assessment. Finally, structural modifications with the potential ability to improve the activity toward B‐Raf are put forward.     

Automated total kidney volume measurements in pre-clinical magnetic resonance imaging for resourcing imaging data,annotations, and source code

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Are risk factors necessary for pretest probability assessment of coronary artery disease? A patient similarity network analysis of the PROMISE trial

BackgroundPretest probability (PTP) calculators utilize epidemiological-level findings to provide patient-level risk assessment of obstructive coronary artery disease (CAD). However, their limited accuracies question whether dissimilarities in risk factors necessarily result in differences in CAD. Using patient similarity network (PSN) analyses, we wished to assess the accuracy of risk factors and imaging markers to identify ≥50% luminal narrowing on coronary CT angiography (CCTA) in stable chest-pain patients.MethodsWe created four PSNs representing: patient characteristics, risk factors, non-coronary imaging markers and calcium score. We used spectral clustering to group individuals with similar risk profiles. We compared PSNs to a contemporary PTP score incorporating calcium score and risk factors to identify ≥50% luminal narrowing on CCTA in the CT-arm of the PROMISE trial. We also conducted subanalyses in different age and sex groups.ResultsIn 3556 individuals, the calcium score PSN significantly outperformed patient characteristic, risk factor, and non-coronary imaging marker PSNs (AUC: 0.81 vs. 0.57, 0.55, 0.54; respectively, p ?< ?0.001 for all). The calcium score PSN significantly outperformed the contemporary PTP score (AUC: 0.81 vs. 0.78, p ?< ?0.001), and using 0, 1–100 and ?> ?100 cut-offs provided comparable results (AUC: 0.81 vs. 0.81, p ?= ?0.06). Similar results were found in all subanalyses.ConclusionCalcium score on its own provides better individualized obstructive CAD prediction than contemporary PTP scores incorporating calcium score and risk factors. Risk factors may not be able to improve the diagnostic accuracy of calcium score to predict ≥50% luminal narrowing on CCTA.     

替代对照品法在镇静安神类药物HPLC快速检验方法中的应用

目的 采用替代对照品法建立镇静安神类药物氯氮卓、马来酸咪达唑仑、硝西泮、艾司唑仑、奥沙西泮、劳拉西泮和阿普唑仑的高效液相色谱快速检验方法。方法 采用Agilent ZORBAX Eclipse Plus C₈色谱柱(4.6 mm×150 mm,5 μm),流动相：0.01 mol·L^-1磷酸二氢钾溶液(pH 2.5)-(甲醇-乙腈1∶1)(57∶43),流速：1.0 mL·min^-1,柱温：30 ℃。采用相对容量因子和紫外光谱相似度双指标进行定性;采用相对校正因子法进行定量分析。结果 在确定的色谱条件下,氯氮?、咪达唑仑、硝西泮、艾司唑仑、奥沙西泮、劳拉西泮和阿普唑仑完全分离;采用紫外光谱相似度和相对容量因子进行定性,结果准确可靠;采用替代对照品法,计算药物的相对校正因子进行含量测定,能有效减少对照品的使用,加快高效液相色谱分析速度。结论 该方法快速、简便、可靠,适用于快速检验镇静安神类药物。     

Dissolution Curve Comparisons Through the F2 Parameter,a Bayesian Extension of the f2 Statistic

Dissolution (or in vitro release) studies constitute an important aspect of pharmaceutical drug development. One important use of such studies is for justifying a biowaiver for post-approval changes which requires establishing equivalence between the new and old product. We propose a statistically rigorous modeling approach for this purpose based on the estimation of what we refer to as the F₂ parameter, an extension of the commonly used f₂ statistic. A Bayesian test procedure is proposed in relation to a set of composite hypotheses that capture the similarity requirement on the absolute mean differences between test and reference dissolution profiles. Several examples are provided to illustrate the application. Results of our simulation study comparing the performance of f₂ and the proposed method show that our Bayesian approach is comparable to or in many cases superior to the f₂ statistic as a decision rule. Further useful extensions of the method, such as the use of continuous-time dissolution modeling, are considered.     

基于论文相似网络拓扑结构的聚类方法比较

以R语言中的复杂网络处理包igraph为工具,基于语义相似性算法构建论文相似网络,然后采用四种代表性网络聚类算法（随机游走法、标签传播法、最大模块度法、边介数法）对构建出的网络进行聚类分析。最后结合金标准和网络社团划分评价指标D函数比较四种算法的准确性和稳定性,发现随机游走算法最为卓越,同时明确了复杂网络的预处理也是一个影响聚类效果的重要因素。     

药物重定位候选药物筛选路径

相对传统新药研发模式,药物重定位策略发现药物新用途具有显著的成本效益优势,能加快药物上市步伐,满足恶性肿瘤、罕见病、个性化医疗等特定领域药物临床用药需求,因而被各界关注。本文主要介绍了药物重定位的一般流程与候选药物筛选路径,如从非理性设计方法向基于相似性、基于结构虚拟筛选、推理与机器学习等理性设计方法发现重定位药物的系统性转变。     

基于链路预测的iSchools联盟院校URL共引潜在关联识别研究

目的：探索iSchools联盟院校关联特征及潜在演进态势,为网络时代背景下iSchools联盟院校间交互结构性能的优化、互联互通引导机制的健全、国际交流与合作策略的完善以及协同创新与发展战略的制定提供可资借鉴的理论和实践参考。方法：以iSchools联盟院校的URL共引网络结构信息为基础,采用10项基于局部信息的相似性指标分别对无权和加权URL共引网络进行链路预测分析,对比各指标的预测性能。引入权重调节系数,剖析强弱连接对预测精度的影响。利用无权PA指标对iSchools联盟院校在网络空间中的潜在关联进行预测识别。结果：不同链路预测指标在无权和加权iSchools联盟院校URL共引网络中的适用性存在一定差异,iSchools联盟院校URL共引链路预测过程中存在一定程度的强弱连接效应。结论：我国高校信息学院与国际院校的联系将日益密切,在iSchools联盟网络中的地位具有较大的提升空间。     

Unique semantic space in the brain of each beholder predicts perceived similarity

The unique way in which each of us perceives the world must arise from our brain representations. If brain imaging could reveal an individual’s unique mental representation, it could help us understand the biological substrate of our individual experiential worlds in mental health and disease. However, imaging studies of object vision have focused on commonalities between individuals rather than individual differences and on category averages rather than representations of particular objects. Here we investigate the individually unique component of brain representations of particular objects with functional MRI (fMRI). Subjects were presented with unfamiliar and personally meaningful object images while we measured their brain activity on two separate days. We characterized the representational geometry by the dissimilarity matrix of activity patterns elicited by particular object images. The representational geometry remained stable across scanning days and was unique in each individual in early visual cortex and human inferior temporal cortex (hIT). The hIT representation predicted perceived similarity as reflected in dissimilarity judgments. Importantly, hIT predicted the individually unique component of the judgments when the objects were personally meaningful. Our results suggest that hIT brain representational idiosyncrasies accessible to fMRI are expressed in an individual''s perceptual judgments. The unique way each of us perceives the world thus might reflect the individually unique representation in high-level visual areas.Everyone’s perception of the world is unique. Psychologists and psychotherapists, using methods including questionnaires and free association, have long attempted to peer into an individual’s subjective experiential world. The unique aspects of our experience coexist with a shared experiential component. We can all recognize the objects that surround us and name them in a common language. Consistent with this shared component of experience, there is evidence that visual stimuli are processed similarly in the brains of different individuals (1). However, the unique way in which each of us perceives an object also must arise from brain activity. Is there an individually unique component to our brain representations?Unidimensional aspects of subjective visual percepts, ranging from estimates of object size, color, vividness, and emotional valence, have separately been found to correlate with interindividual variation in both univariate regional-average activation and cortical anatomy (2, 3). However, it remains unclear how a person’s multidimensional subjective percept reflects the multivariate brain-activity pattern that represents a particular object.Functional magnetic resonance imaging (fMRI) studies of object vision have focused largely on commonalities among subjects and category averages across particular stimuli. These studies have revealed regions in human inferior temporal cortex (hIT) that preferentially respond to specific categories (4–9) as well as widely distributed category information (10). More recently, similarity analyses of response patterns to particular stimulus images have revealed exemplar-specific representations (11–14), clustering of response patterns by natural categories (15–17), and reinstatement of neural representations during memory recall (18, 19). These prior studies either tacitly assumed similar representations across individuals or explicitly demonstrated commonalities between individuals and even between species (14, 20–29).Previous studies have shown that the hIT representation has a semantic component (23) and is reflected in perception at the level of group averages (30). Here we tested the hypothesis that an individual’s hIT representation predicts idiosyncrasies in his or her perception of natural objects. Because of hIT’s reciprocal connections to the memory regions of the medial temporal lobe (31), we further predicted that personally meaningful objects elicit individually unique mnemonic associations and are more distinctly represented in each individual.We presented familiar and unfamiliar object images to subjects during fMRI and investigated whether early visual cortex (EVC) and hIT exhibit individually unique representations. We characterized the representational geometry of each region by the dissimilarity matrix of activity patterns elicited by particular object images. This matrix is called the “representational dissimilarity matrix” (RDM) (16). To address whether the detailed representational geometries are reflected in behavior, we tested whether individual idiosyncrasies in similarity judgments can be predicted on the basis of a subject’s brain RDM.