聚类分析法在抗菌药物设计中的应用

药物研究常希望通过合成较少的化合物，就能发现最佳活性的同系物或类似物，以摆脱过去那种“泛泛合成、随机筛选”的经验性方法，减少盲目性，加快创制新药的步伐。为此，选择和确定合成对象的类型和数量就显得十分重要。本文采用Q－型聚类分析的统计方法，根据不同化合物或理化参数之间的相似程度，将其妇组分群，并在考虑原料、试剂、合成难易和费用高低的基础上，从合成的最小数量的化合物中，获得活性受结构因素制约的最大信息。1．分类系统的形成1．1将原始数据标准化。使用公式：其中S为标准差。得到矩阵X“1．2计算分类统计量一相…     

β取代桂皮酰胺类衍生物取代基及结构参数的模糊图聚类分析

本文用模糊图聚类分析法对β取代桂皮酰胺类衍生物的取代基及结构参数分别进行Q型和R型群分析,得到满意结果。     

聚类分析法在术类药材分类中的应用

对9种不同品种术类药材挥发油的主要成分进行色谱扫描,从薄层色谱扫描中测得主要成份相对含量的差异,用聚类分析的数学方法进行处理,准确地区分了术类的品种。     

先导化合物结构优化策略(七)——肽类分子结构修饰与改造

多肽分子大多为天然的内源性配体,与受体的亲和力强,选择性好,是一类比较容易成为先导化合物及药物的分子。许多药物都是从多肽分子进行结构优化改造而得,如降压药物卡托普利、抗丙肝药物特拉匹韦等。目前多肽分子开发面临的主要问题包括稳定性差、半衰期短、血浆清除率高等低成药性缺陷;通常只能注射使用,患者的依从性较差;生产工艺复杂,生产成本较高。因此,对多肽分子进行合理的修饰和改造既可以降低肽类分子的生产成本,又可以改善肽类分子的成药性。本文从改善肽类分子成药性的角度综述了肽类分子结构修饰与改造策略,根据是否对肽链骨架进行修饰,将修饰策略分为两类:一类是针对肽链骨架的改造,包括非天然氨基酸修饰、伪肽化策略、逆肽策略、环化策略、末端结构修饰等;另一类是在多肽骨架不变的基础上,引入其他基团进行结构优化和性能改造,包括高级脂肪酸修饰、聚乙二醇修饰、蛋白融合策略、胆固醇修饰等。     

模糊聚类分析法在氨基酸分子分析中的应用

文中选用氨基酸分子的相对分子量、pI值、疏水性值以及保守性值这四个参数,利用模糊聚类的方法,对20种氨基酸分子进行了分类。通过对分类结果的分析,有助于研究蛋白质的相似性问题。     

气相色谱数据的聚类分析法评价中药厚朴的质量

本文对中药厚朴进行气相色谱分析,根据样品组分的相对含量,用样品的多指标点绘法,对这些样品进行聚类分析,为评价其真伪及质量的优劣进行了初步的尝试,获得了一定结果。     

指纹图谱结合聚类分析法研究清热解毒口服液的质量

目的 建立清热解毒口服液HPLC指纹图谱,结合聚类分析法,为评估清热解毒口服液的质量提供方法,评估投料的合规性。方法 用HPLC法,C₁₈色谱柱(250 mm×4.6 mm, 5μm),以乙腈(A)-1 mL·L^-1甲酸溶液(B)体系进行梯度洗脱,检测波长为278 nm,流速为1.0 mL·min^-1,柱温为35℃,用中药色谱指纹图谱相似度评价系统处理数据,并进行聚类分析与主成分分析。结果 用该方法对50批制剂进行检测,清热解毒口服液质量存在较大差异,聚类分析结果表明不同地区生产的清热解毒口服液的原料有差异,或者未合规投料。结论 该方法可用于评估清热解毒口服液的质量。     

基于紫外光谱和聚类分析法结合的布渣叶鉴别研究

目的建立布渣叶药材紫外指纹图谱的聚类分析方法,为布渣叶的光谱鉴别提供实验依据。方法以紫外一阶导数光谱指纹图谱为依据,采用聚类分析法对30份布渣叶样品和4种叶类中药进行聚类分析。结果紫外光谱结合聚类分析法可以准确地将布渣叶和其它4种叶类中药鉴别出来,并且反映了各样品之间的亲疏远近关系。结论紫外光谱聚类法可为布渣叶提供一个快捷、准确、可行的鉴别方法。     

聚类分析法在砂仁及其伪品鉴别分类中的应用

以“南药”砂仁及其伪品为研究对象，从砂仁及其伪品的紫外光谱中获取数量化特征，通过聚类分析，在计算机上实现了样品的鉴别分类     

高分辨气相色谱—模糊聚类分析法在术类药材分类中的应用

本文用高分辨气相色谱—阶程序升温的方法对术类12种药材进行色谱分析,所得相应色谱保留指数的样品组分百分含量用模糊聚类分析的数学方法通过计算机进行处理,正确划分了术类药材的种类,取得初步成果,所提出的方法学对中药材鉴定和分类具有一定的指导意义。     

The uses and benefits of cluster analysis in pharmacy research

PURPOSE: Cluster analysis (CA) refers to a set of analytic procedures that reduce complex multivariate data into smaller subsets or groups. Compared with other data reduction methods, such as factor analysis, CA yields groupings that are based on the similarity of whole cases, as opposed to the individual variables that comprise those cases. CA represents a valuable analytic tool for the health sciences, and may be used to devise patient or consumer profiles, or in the development of classification systems or taxonomies. CA has become a more widely used analytic tool because before the advent of personal computers with high processing power, CA methods were too complex to be time efficient. Yet in the past few decades, interest in and the applied use of CA have advanced considerably. CA tools are now integrated into most popular statistical software packages and are therefore more accessible. METHODS: The authors provide a discussion of CA that seeks to introduce the various methods, issues, and considerations to the researcher who is largely unfamiliar with CA. A conceptual understanding of CA is guided through breaking down CA into a series of steps and issues to consider including composition of the dataset, selection of variables, decisions about standardizing variables, selecting a measure of association, selecting a clustering method, determining the number of clusters, and interpretation. RESULTS/CONCLUSIONS: Because the range of CA methods is diverse, and because the steps within each method are so varied, an attempt to offer a complete "how-to" process in a single article is imprudent. Rather, the novice reader will be able to use this article as a starting point for conducting his or her own particular CA study.     

Identifying subtypes of dual alcohol and marijuana users: a methodological approach using cluster analysis

Alcohol is the most common psychoactive substance used with marijuana. However, little is known about the potential impact of different levels of use of both alcohol and marijuana and their influence on risky behaviors, injuries and psychosocial functioning. A systematic approach to identifying patterns of alcohol and marijuana use associated with increased risks has not yet been identified in the literature.We report on the secondary analysis of data collected from a RCT conducted in a busy urban emergency department. Cluster analysis was performed on the patterns of past 30-day alcohol and marijuana use in two random subsamples N₁ = 210 and N₂ = 217. Four distinct subtypes of those who use both alcohol and marijuana were identified: (1) Daily Marijuana and Weekly Alcohol users; (2) Weekly Alcohol and Weekly Marijuana users; (3) Daily Alcohol and Daily Marijuana users; and (4) Daily Alcohol, Weekly Marijuana users. The four subtypes were replicated in both subsamples and examination of the external validity using ANOVA to determine cluster differences on psychosocial and behavioral variables confirmed the theoretical relevance of different patterns of alcohol and marijuana use. There were significantly different psychosocial negative consequences and related risky behaviors among subtypes.We found that Daily Alcohol and Daily Marijuana users are at the highest risk to experience more negative consequences and engage in a broader spectrum of risky behaviors related to both substances, than the other three types of alcohol and marijuana users.     

丹参药材中活性成分的测定及其聚类分析

目的 建立测定不同产地丹参药材中主要活性成分的方法,根据含量水平对丹参药材进行聚类分析.方法 采用HPLC指纹图谱法,分析柱为C18柱(150 mm×4.6 mm,10μm),用甲醇-1%四氢呋喃的1%甲酸水溶液进行梯度洗脱;测定波长286 nm,进行丹参活性成分的指纹图谱分析,以指纹图谱评价软件结合SPSS 13.0统计软件进行聚类分析.结果 定量分析了丹参药材的8个主要活性成分,所分析的丹参大致划分为两类.结论 所建方法分离度好、准确度高,适宜于丹参药材活性成分的测定;不同产地丹参药材之间活性成分的差异较大,其分布无明显的规律性;丹参药材在地理上的分布无明显的区域界限.     

聚类分析在红霉素摇瓶培养基无机盐分析中的应用

红色糖多孢菌的摇瓶培养基中使用不同有机氮源时红霉素的效价明显不同。通过对培养基中不同有机氮源所含无机盐的聚类分析。发现无机磷为影响红霉素效价的主要因素。培养基中无机磷含量高了会显著抑制红霉素的生物合成。     

Characterizing decision-making and reward processing in bipolar disorder: A cluster analysis

The presence of abnormalities in emotional decision-making and reward processing among bipolar patients (BP) has been well rehearsed. These disturbances are not limited to acute phases and are common even during remission. In recent years, the existence of discrete cognitive profiles in this psychiatric population has been replicated. However, emotional decision making and reward processing domains have barely been studied. Therefore, our aim was to explore the existence of different profiles on the aforementioned cognitive dimensions in BP. The sample consisted of 126 euthymic BP. Main sociodemographic, clinical, functioning, and neurocognitive variables were gathered. A hierarchical-clustering technique was used to identify discrete neurocognitive profiles based on the performance in the Iowa Gambling Task. Afterward, the resulting clusters were compared using ANOVA or Chi-squared Test, as appropriate. Evidence for the existence of three different profiles was provided. Cluster 1 was mainly characterized by poor decision ability. Cluster 2 presented the lowest sensitivity to punishment. Finally, cluster 3 presented the best decision-making ability and the highest levels of punishment sensitivity. Comparison between the three clusters indicated that cluster 2 was the most functionally impaired group. The poorest outcomes in attention, executive function domains, and social cognition were also observed within the same group. In conclusion, similarly to that observed in “cold cognitive” domains, our results suggest the existence of three discrete cognitive profiles concerning emotional decision making and reward processing. Amongst all the indexes explored, low punishment sensitivity emerge as a potential correlate of poorer cognitive and functional outcomes in bipolar disorder.     

Statistical analysis of the effects of common chemical substituents on ligand potency

The results of a statistical analysis of more than 84,000 compounds from lead optimization programs against 30 different protein targets is presented, with a focus on the effects that different chemical substituents have on compound potency. It is observed that the potency changes induced by most chemical groups follows a nearly normal distribution centered near zero (i.e., no effect on potency). However, the widths of the distributions vary significantly between different substituents, and these effects cannot be rationalized by simple physicochemical parameters. In addition, certain substituents consistently bias the distribution toward higher or lower potency, suggesting the existence of preferred and nonpreferred chemical groups for lead optimization. The implications of these results for understanding protein-ligand recognition and for enhancing the efficiency and speed of lead optimization will be discussed.     

Identifying cluster subtypes for the prevention of adolescent smoking acquisition

School-based smoking prevention programs are typically identical for all students. Tailoring prevention materials to focus on individual needs with an emphasis on students at highest risk is a promising alternative. Recent prevention programs have tailored materials based on the Stages of Acquisition, an extension of the Stages of Change used to tailor smoking cessation materials effectively for adults. Three stages of acquisition have been identified: Acquisition Precontemplation (aPC), Acquisition Contemplation (aC) and Acquisition Preparation (aPR). However, about 90% of nonsmoking adolescents classify themselves in the aPC stage. A cluster analysis was performed, using the Decisional Balance and Situational Temptations scales, for three random subsamples of adolescents within the aPC stage (N(1)=N(2)=N(3)=514). Four distinct subtypes were identified in each subsample: High Risk, Protected, Ambivalent, and Risk Denial. External validity was established using family support for nonsmoking, peer variables, and stage classification at follow-up assessment (12, 24, and 36 months). Family support for nonsmoking was related to subtype much more strongly than peer interactions. Subjects in the Protected subgroup were the most likely to remain in the aPC stage at each follow-up assessment. Subtype membership, along with membership in the aC and aPR stages, provides important additional information for tailoring smoking prevention materials. Tailored interventions can focus on those adolescents at highest risk and limit or avoid expending resources on those at very low risk.     

临床常见病原菌对环丙沙星耐药性趋势分析

分析临床常见病原菌对环丙沙星耐药性趋势,为临床合理应用喹诺酮类抗菌药提供依据。用whonet4(1999年版）软件对解放军总医院1994年3月至1999年3月5年间检测的临床常见病原菌环丙沙星药敏试验结果进行分析,药敏采用纸片扩散法。结果,8种临床常见菌：表葡球菌、金葡球菌、粪肠球菌、大肠埃希氏菌、肺炎克雷伯氏菌、奇异变形杆菌、阴沟肠杆菌、铜绿假单胞菌5年间对环丙沙星耐药均呈上升趋势,其中大肠埃希氏菌和表葡球菌的耐药率增长更为明显,分别达71.5%和43.2%;而分离率与大肠埃希氏菌和表葡球菌接近的铜绿假单胞菌和肺炎克雷伯氏菌耐药率仅为23%和10.8%,耐药率的增长存在明显的差异。提示临床常见病原菌对环丙沙星耐药性增长趋势不但与临床广泛应用喹诺酮类药物有关,而且与经验性应用喹诺酮类药物治疗不同部位感染也有相当密切的关系。