Geographic Clustering Patterns in Mortality from Biliary Tract Cancer in Japan

We calculated the standardized mortality ratios (SMRs) of biliary tract cancer (BTC) in Japan from 1981 to 1990 and statistically analyzed the results according to 333 Secondary Areas of Medical Care, as well as sex and subsite [gallbladder cancer (GBC) and extrahepatic bile duct cancer (BDC)], in order to examine geographic clustering patterns of BTC. In GBC in both sexes, the Secondary Areas of Medical Care with high SMRs were clustered in the eastern part of Japan. In BDC in both sexes, the Areas with high SMRs were clustered between the northern and eastern parts of Japan. In comparison with GBC, this clustering favored the northern part of Japan. In males, the clustering pattern in mortality from BTC was mainly due to the occurrence of BDC. In females, the clustering pattern in mortality from BTC reflected that of GBC. The clustering of BTC, especially GBC, seems to be related to the distribution of plains, basins, and rivers.     

基于伪F统计量的模糊聚类方法在医疗质量综合评价中的应用

目的探讨一种新的基于伪F统计量的最佳聚类分析方法,该方法不需要预先选择类的数目作为先验值.并有效地应用于医疗质量的综合评价.方法首先,应用FCM模糊聚类法(Fuzzy Clustering Method)进行聚类,然后应用PFS(Pseudo F-statistics)统计量作为一个判别函数来确定最佳类数目.结果将该方法应用于某院2002年度各科室医疗质量综合评价,得到了一种合理的综合评价结果.结论该方法基于没有聚类数据的任何先验知识和组成成分信息的前提下,考虑如何确定数据的分类结构.根据应用的情况,发现该方法是医疗质量综合评价的有力工具.     

基于聚类分析的径向基神经网络用于证候诊断的研究

目的:优化中医证候诊断模型,为中医证候诊断标准的研究提供可行性方法.方法:提出用于中医证候诊断的径向基(Radial Basis Function,RBF)神经网络,利用聚类分析确定RBF神经网络隐层的参数,运用最小二乘确定RBF神经网络输出层的参数.结果:通过模型检验,证候诊断模型判准率比BP网络模型判准率高;证候诊断模型训练速度比BP网络模型快.结论:基于聚类分析的RBF神经网络用于中医证候诊断的研究是可行的和有效的.     

一种用于寻找典型病理图像的聚类分析方法

目的：探讨利用K—medoids聚类分析方法来寻找典型病理图像。方法：对正常、低度和高度鳞状上皮内病变宫颈细胞的51个特征参数进行标准化处理，以消除原始变量数量及量纲影响。运用统计软件R对所有特征参数进行K—medoids聚类分析。结果：对于正常、低度和高度鳞状上皮内病变宫颈细胞的分类正确率分别为91．7％、98．0％和92，0％。作为类中心点的3个病理图片可作为典型病理图片指导临床及教学研究。结论：该方法简单、方便，客观性强，可应用到其他医学领域定量研究。     

A novel region-based level set method initialized with mean shift clustering for automated medical image segmentation

Appropriate initialization and stable evolution are desirable criteria to satisfy in level set methods. In this study, a novel region-based level set method utilizing both global and local image information complementarily is proposed. The global image information is extracted from mean shift clustering without any prior knowledge. Appropriate initial contours are obtained by regulating the clustering results. The local image information, as extracted by a data fitting energy, is employed to maintain a stable evolution of the zero level set curves. The advantages of the proposed method are as follows. First, the controlling parameters of the evolution can be easily estimated by the clustering results. Second, the automaticity of the model increases because of a reduction in computational cost and manual intervention. Experimental results confirm the efficiency and accuracy of the proposed method for medical image segmentation.     

Multiple variants aggregate in the neuregulin signaling pathway in a subset of schizophrenia patients

Despite the strongly held view that schizophrenia (SZ) shows substantial genetic heterogeneity, pathway heterogeneity, as seen in cancer where different pathways are affected in similar tumors, has not been explored. We explore this possibility in a case-only study of the neuregulin signaling pathway (NSP), which has been prominently implicated in SZ and for which there is detailed knowledge on the ligand- and receptor-processing steps through β- and γ-secretase cleavage. We hypothesize that more than one damaging variants in the NSP genes might be necessary to cause disease, leading to an apparent clustering of such variants in only the few patients with affected NSP. We analyze linkage and next-generation sequencing results for the genes encoding components of the pathway, including NRG1, NRG3, ERBB4, β-secretase and the γ-secretase complex. We find multiple independent examples of supporting evidence for this hypothesis: (i) increased linkage scores over NSP genes, (ii) multiple positive interlocus correlations of linkage scores across families suggesting each family is linked to either many or none of the genes, (iii) aggregation of predicted damaging variants in a subset of individuals and (iv) significant phenotypic differences of the subset of patients carrying such variants. Collectively, our data strongly support the hypothesis that the NSP is affected by multiple damaging variants in a subset of phenotypically distinct patients. On the basis of this, we propose a general model of pathway heterogeneity in SZ, which, in part, may explain its phenotypic variability and genetic complexity.     

济南市2014—2018年猩红热流行特征及时空聚集性分析

目的 研究济南市猩红热的流行特征,并对时空聚集性进行分析,为猩红热的防控工作提供依据。方法 从国家疾病监测信息报告管理系统中获取济南市2014—2018年猩红热疫情资料,采用描述性流行病学方法及时空重排扫描统计方法分析猩红热病例的流行病学和时空分布特征。结果 2014—2018年济南市累计报告猩红热7 297例,年均发病率20.46/10万。全年出现冬季和春季2个发病高峰。病例主要集中在1~9岁儿童,幼托儿童、学生及散居儿童发病数占总病例数的99.70%,男女性别比1.70∶1。市中区、历城区、槐荫区、天桥区、历下区是主要高发地区,占病例总数的83.50%。按年进行时空聚集性分析,每年均探测到3个时空聚集区,具有显著时空聚集性。结论 2014—2018年济南市猩红热处于上升趋势,学校和托幼机构是发病的高危场所,应根据时空分布及流行特征,制定相应的防控措施,控制猩红热的发生和扩散。     

A multivariate hypothesis testing framework for tissue clustering and classification of DTI data

The primary aim of this work is to propose and investigate the effectiveness of a novel unsupervised tissue clustering and classification algorithm for diffusion tensor MRI (DTI) data. The proposed algorithm utilizes information about the degree of homogeneity of the distribution of diffusion tensors within voxels. We adapt frameworks proposed by Hext and Snedecor, where the null hypothesis of diffusion tensors belonging to the same distribution is assessed by an F‐test. Tissue type is classified according to one of the four possible diffusion models, the assignment of which is determined by a parsimonious model selection framework based on Schwarz Criterion. Both numerical phantoms and diffusion‐weighted imaging (DWI) data obtained from excised rat and pig spinal cords are used to test and validate these tissue clustering and classification approaches. The unsupervised clustering method effectively identifies distinct regions of interest (ROIs) in phantoms and real experimental DTI data. Copyright © 2009 John Wiley & Sons, Ltd.     

某养老机构新型冠状病毒肺炎聚集性疫情流行病学特征分析

目的对某养老机构发生一起新型冠状病毒肺炎(COVID-19)聚集性疫情进行回顾性流行病学调查和分析。方法采用"新型冠状病毒肺炎防控方案(第三版)"推荐的个案调查表和依照"新型冠状病毒肺炎聚集性疫情流行病学调查指南(试行第一版)"进行。结果某养老机构有8名护理人员和住院老人感染新冠肺炎,年龄中位为59岁,男、女比例1∶7。于末次暴露后4~15 d确诊。排查出225名密切接触者,无三代院内续发传播;不排除无症状感染存在传染的可能性;病亡1例。结论本次聚集性疫情的感染来源于新冠肺炎确诊病例。建议防控策略应关注养老机构、监管场所等重点部门、重点人群的管控与监测。