Polymicrogyric Cortex may Predispose to Seizures via Abnormal Network Topology: An fMRI Connectomics Study

Polymicrogyria is a significant malformation of cortical development with a high incidence of epilepsy and cognitive deficits. Graph theoretic analysis is a useful approach to studying network organization in brain disorders. In this study, we used task‐free functional magnetic resonance imaging (fMRI) data from four patients with polymicrogyria and refractory epilepsy. Gray matter masks from structural MRI data were parcellated into 1,024 network nodes. Functional “connectomes” were obtained based on fMRI time series between the parcellated network nodes; network analysis was conducted using clustering coefficient, path length, node degree, and participation coefficient. These graph metrics were compared between nodes within polymicrogyric cortex and normal brain tissue in contralateral homologous cortical regions. Polymicrogyric nodes showed significantly increased clustering coefficient and characteristic path length. This is the first study using functional connectivity analysis in polymicrogyria—our results indicate a shift toward a regular network topology in polymicrogyric nodes. Regularized network topology has been demonstrated previously in patients with focal epilepsy and during focal seizures. Thus, we postulate that these network alterations predispose to seizures and may be relevant to cognitive deficits in patients with polymicrogyria.     

Multidimensional representation of odors in the human olfactory cortex

What is known as an odor object is an integrated representation constructed from physical features, and perceptual attributes mainly mediated by the olfactory and trigeminal systems. The aim of the present study was to comprehend how this multidimensional representation is organized, by deciphering how similarities in the physical, olfactory and trigeminal perceptual spaces of odors are represented in the human brain. To achieve this aim, we combined psychophysics, functional MRI and multivariate representational similarity analysis. Participants were asked to smell odors diffused by an fMRI‐compatible olfactometer and to rate each smell along olfactory dimensions (pleasantness, intensity, familiarity and edibility) and trigeminal dimensions (irritation, coolness, warmth and pain). An event‐related design was implemented, presenting different odorants. Results revealed that (i) pairwise odorant similarities in anterior piriform cortex (PC) activity correlated with pairwise odorant similarities in chemical properties (P < 0.005), (ii) similarities in posterior PC activity correlated with similarities in olfactory perceptual properties (P <0.01), and (iii) similarities in amygdala activity correlated with similarities in trigeminal perceptual properties (P < 0.01). These findings provide new evidence that extraction of physical, olfactory and trigeminal features is based on specific fine processing of similarities between odorous stimuli in a distributed manner in the olfactory system. Hum Brain Mapp 37:2161–2172, 2016. © 2016 Wiley Periodicals, Inc.     

色谱指纹图谱相似度方法的研究进展

色谱指纹图谱相似度是中药质量控制的重要方法之一,研究中药色谱指纹图谱的相似度计算方法对于中药质量控制很有意义。作者介绍了数量相似度、相似性相似度和差异性相似度3类相似度方法的研究现状,分析了3类相似度方法各自的特点与局限,对相似度方法的改进进行了总结,并对相似度方法存在的问题、改进趋势与应用作出了展望。     

白桦总三萜类成分高效液相色谱指纹图谱研究

目的建立白桦总三萜类成分的HPLC指纹图谱分析方法,研究不同采收期白桦药材的质量。方法以Kromasil C18柱（4.6mm×250mm,5μm）为色谱柱,流动相乙腈-水,采用梯度洗脱,流速为1.0ml/min,柱温25℃,检测波长280nm;进样量20μl;检测时间60min,对10批白桦总三萜类成分的HPLC指纹图谱进行研究,并运用相似度评价法对数据进行分析。结果实验标定9个共有峰,不同采收期的白桦指纹图谱相似度较好。结论该方法准确可靠,重复性好,用于白桦的质量评价切实可行;不同采收期白桦总三萜类化学组成相似,其相对比例较稳定。     

近红外光谱相似度用于中药提取物质量控制方法的研究

建立了一种基于近红外光谱相似度的中药提取物质量控制方法.从5种中药提取物中随机划分校正集与验证集,取与校正集样品平均光谱的相似度大于99%的样品作为标准样品库,建立相似度计算模型.利用所建模型预测样品近红外光谱的相似度.结果显示:相似度较高的样品,其含量测定数据也较接近平均值.而且近红外光谱还能够反映提取物样品除有效成分含量之外的差异.     

复方氨酚烷胺胶囊中3种主要成分的测定及溶出度比较

目的建立同时测定复方氨酚烷胺胶囊中对乙酰氨基酚、马来酸氯苯那敏、咖啡因3个组分含量的方法,并应用此方法考察上述3组分的体外溶出差异。方法采用Alltima C18（4．6mm×150mm,5μm）色谱柱,流动相：甲醇．0．05moL·L-1 KH2P04（用磷酸调节pH至3．0）．三乙胺（20：80：0．021,流速：lmL·min-1,检测波长：216nm。溶出度采用转篮法,以水1000mL为溶出介质,转速80r．min-1,温度（37±0．5）℃,分别在不同时间取样计算各成分的累积溶出百分率,采用相似因子进行溶出曲线的相似性比较。结果对乙酰氨基酚、马来酸氯苯那敏、咖啡因的线性范围分别为2．50～250．10,0．20～19．50,0．61～60．74gg·mL-1,r分别为1．000,1．000,0．9999。马来酸氯苯那敏、咖啡因与对乙酰氨基酚的相似因子分别为34,73。结论该方法简便、准确、重复性好,可用于控制该制剂的质量,溶出度测定实验的结果表明该胶囊中上述3个组分不完全具有同步溶出的特点。     

Drug–drug interaction through molecular structure similarity analysis

Background

Drug–drug interactions (DDIs) are responsible for many serious adverse events; their detection is crucial for patient safety but is very challenging. Currently, the US Food and Drug Administration and pharmaceutical companies are showing great interest in the development of improved tools for identifying DDIs.

Methods

We present a new methodology applicable on a large scale that identifies novel DDIs based on molecular structural similarity to drugs involved in established DDIs. The underlying assumption is that if drug A and drug B interact to produce a specific biological effect, then drugs similar to drug A (or drug B) are likely to interact with drug B (or drug A) to produce the same effect. DrugBank was used as a resource for collecting 9454 established DDIs. The structural similarity of all pairs of drugs in DrugBank was computed to identify DDI candidates.

Results

The methodology was evaluated using as a gold standard the interactions retrieved from the initial DrugBank database. Results demonstrated an overall sensitivity of 0.68, specificity of 0.96, and precision of 0.26. Additionally, the methodology was also evaluated in an independent test using the Micromedex/Drugdex database.

Conclusion

The proposed methodology is simple, efficient, allows the investigation of large numbers of drugs, and helps highlight the etiology of DDI. A database of 58 403 predicted DDIs with structural evidence is provided as an open resource for investigators seeking to analyze DDIs.     

叶下珠种质资源遗传多样性的ISSR分析

目的 对分布于我国30个居群的叶下珠进行遗传多样性分析。方法 采用ISSR分子标记技术,研究来自我国重庆、陕西、河南、云南、广西、广东、浙江、贵州、福建、海南省区共30个叶下珠居群的遗传多样性。结果 从60个ISSR引物中筛选出24个用于扩增,共扩增得到264条条带,其中共有条带19条,多样性条带245条,多态位点百分率（PPB）为92.80%,遗传相似性系数（GS）值在0.579 5～0.916 7,多态性较高。UPGMA聚类结果显示我国叶下珠居群大致可以分为3支,即内陆分支、沿海分支及位于云南省区的过渡分支;个别居群呈现明显的居群特异性。结论 叶下珠种质资源遗传多样性较高。     

Fisher成分分析法用于决明子化学指纹特征相似性研究

目的:探求Fisher成分分析法用于大、小决明子化学指纹特征相似的研究,为大、小决明子的分类提供依据。方法:对获得的指纹图谱进行数字化处理并得到大、小决明子的标准指纹图谱,然后用Fisher成分分析法提取大、小决明子化学指纹图谱中的隐含化学特征,对大、小决明子进行质量模式分类,并与主成分分析法及标准图谱法进行分类效果对比研究。结果:Fisher成分分析法能更好地表征大、小决明子的化学模式特征,分类准确性高。结论:根据Fisher成分分析法可识别大、小决明子的化学指纹特征的内在差异,可用于鉴别中药材真伪。