Bayesian consensus clustering for multivariate longitudinal data

In clinical and epidemiological studies, there is a growing interest in studying the heterogeneity among patients based on longitudinal characteristics to identify subtypes of the study population. Compared to clustering a single longitudinal marker, simultaneously clustering multiple longitudinal markers allow additional information to be incorporated into the clustering process, which reveals co-existing longitudinal patterns and generates deeper biological insight. In the current study, we propose a Bayesian consensus clustering (BCC) model for multivariate longitudinal data. Instead of arriving at a single overall clustering, the proposed model allows each marker to follow marker-specific local clustering and these local clusterings are aggregated to find a global (consensus) clustering. To estimate the posterior distribution of model parameters, a Gibbs sampling algorithm is proposed. We apply our proposed model to the primary biliary cirrhosis study to identify patient subtypes that may be associated with their prognosis. We also perform simulation studies to compare the clustering performance between the proposed model and existing models under several scenarios. The results demonstrate that the proposed BCC model serves as a useful tool for clustering multivariate longitudinal data.     

百年乐与人参黄芪合剂对心血管系统的药理作用比较

百年乐和人参黄芪合剂对心血管系统的作用研究表明:百年乐能加速小鼠肠系膜微循环障碍的恢复,增加离体兔耳血管的流量,使主动脉平滑肌松弛,对抗心肌缺氧,抑制血栓形成,其作用强于人参黄芪合剂。     

Multivariate modelling of responses to conditional items: New possibilities for latent class analysis

Questionnaire data may contain missing values because certain questions do not apply to all respondents. For instance, questions addressing particular attributes of a symptom, such as frequency, triggers or seasonality, are only applicable to those who have experienced the symptom, while for those who have not, responses to these items will be missing. This missing information does not fall into the category ‘missing by design’, rather the features of interest do not exist and cannot be measured regardless of survey design. Analysis of responses to such conditional items is therefore typically restricted to the subpopulation in which they apply. This article is concerned with joint multivariate modelling of responses to both unconditional and conditional items without restricting the analysis to this subpopulation. Such an approach is of interest when the distributions of both types of responses are thought to be determined by common parameters affecting the whole population. By integrating the conditional item structure into the model, inference can be based both on unconditional data from the entire population and on conditional data from subjects for whom they exist. This approach opens new possibilities for multivariate analysis of such data. We apply this approach to latent class modelling and provide an example using data on respiratory symptoms (wheeze and cough) in children. Conditional data structures such as that considered here are common in medical research settings and, although our focus is on latent class models, the approach can be applied to other multivariate models. Copyright © 2009 John Wiley & Sons, Ltd.     

当归对肺纤维化大鼠肺形态学及胶原的影响

目的　观察当归对博莱霉素所致的肺间质纤维化大鼠的肺形态学及胶原的影响 ,探讨其作用机制。方法　 36只大鼠随机分为对照组、模型组及当归组。气管内注入博莱霉素复制大鼠肺间质纤维化模型 ,次日当归组每日腹腔内注射当归注射液 15 0mg/kg,于第 7及第 2 8天每组分别处死 6只大鼠 ,观察肺间质纤维化形成的病理变化及血清Ⅰ型胶原的含量。结果　当归能明显减轻肺泡炎和肺纤维化程度 ,与模型组比较 ,当归组血清Ⅰ型胶原含量于第 7、 2 8天明显降低 (P均 <0 0 5 )。结论　当归能减慢肺间质纤维化的进程 ,对肺间质纤维化有一定的保护作用。     

Seasonal variation in the content of a febrifugine and isofebrifugine alkaloid mixture in aerial parts of <Emphasis Type="Italic">Hydrangea macrophylla</Emphasis> var. <Emphasis Type="Italic">Otaksa</Emphasis>, with special reference to its antimalarial activity

Febrifugine and isofebrifugine alkaloid mixtures extracted from the leaves and buds of Hydrangea macrophylla var. Otaksa, collected during different months, in Japan, were quantified using high-performance liquid chromatography. Leaves collected during the flowering season, namely from June to August, contained 0.16–0.31 mg/g of the alkaloid mixture, whereas those collected from September to December had less than 0.03 mg/g of the mixture. However, extracts of buds harvested from October to February contained a consistently larger amount (more than 0.49 mg/g) of the alkaloids. Hot-water extracts from the leaves and buds collected during different seasons were evaluated for antimalarial activity against Plasmodium yoelii 17XL in mice. The extract of leaves collected in August demonstrated high antimalarial activity, and all mice that received the extract survived the infection. In contrast, the extract of leaves collected in December showed little activity. The extract of buds collected in December cleared parasites, but with subsequent mortality to mouse. The present results show that the amount of antimalarial agent—febrifugine and isofebrifugine mixture—in H. macrophylla var. Otaksa is both part- and season-dependent, suggesting that the choice of plant parts and their harvesting season are important factors worth considering in the pharmacological use of medicinal plants.     

当归多糖及其中性组分对巨噬细胞分泌TNF-α的影响

目的 :观察当归多糖 (ASP)及其中性组分 (ASP 1)在体内外对小鼠腹腔巨噬细胞 (MФ)分泌TNF α的影响。方法 :直接制取小鼠腹腔MФ ,与ASP及ASP 1共同培养 16h ;ASP及ASP 112 5、2 5 0mg kg经口灌胃给药 7d ,于第 7d制取MФ ,体外培养 16h ,分别观察ASP及ASP 1在体外均可显著增强MФ对TNF α的分泌。ASP及ASP 1体内给药无直接诱导MФ分泌TNF α的功能。结论 :ASP及ASP 1在体内外均可增强小鼠腹腔MФ分泌TNF α的功能。     

膜荚黄芪毛状根中异黄酮成分的反相高效液相色谱分析

对膜荚黄芪毛状根中6种异黄酮成分进行了反相高效液相色谱法测定。色谱柱为NucleosilC₁₈柱,流动相为甲醇—水(3∶2和3∶1,v/v),检测波长为254nm和280nm。6种异黄酮成分为:10-羟基-3,9-二甲氧基紫檀烷,(3R)8,2’-二羟基-7,4’-二甲氧基异黄烷,芒柄花素(7-羟基-4’-甲氧基异黄酮),8,3’-二羟基-7,4’-二甲氧基异黄酮,2’-羟基-3’,4’-二甲氧基异黄烷-7-O-葡萄吡喃糖甙,毛蕊异黄酮(7,3’-二羟基-4’-甲氧基异黄酮)。异黄酮浓度在2.5～12.5μg范围内与峰面积有良好的线性关系;加样回收率为96.47%～103.33%;精密度试验相对标准偏差为2.57%～6.52%;测得黄芪毛状根中6种异黄酮成分的含量在0.0005%～0.0065%之间。     

黄芪、小柴胡冲剂联合辅酶Q10治疗病毒性心肌炎

目的观察黄芪、小柴胡冲剂联合辅酶Q10治疗病毒性心肌炎(VMC)的临床疗效.方法治疗组(30例)应用黄芪注射液、小柴胡冲剂和辅酶Q10;对照组(30例)用GIK极化液、辅酶Q10和维生素C,两组患者无禁忌证者均给予β-受体阻滞剂,钙拮抗剂和对症治疗.两组疗程均为3个月.结果治疗组临床症状和心律失常总有效率分别为73.3%和86.6%,高于对照组的43.3%和63.3%(p＜0.05).结论黄芪、小柴胡冲剂联合辅酶Q10对VMC有较好疗效,且无明显不良反应.     

地黄合剂降血糖作用的实验性研究

本文通过用四氧嘧啶复制小白鼠糖尿病模型,以血清中血糖及胰岛素水平为指标,研究了地黄合剂对高糖动物的降血糖作用。结果表明,注射四氧嘧啶前小白鼠血糖为173.47±5.23mg/100ml注射后血糖升高至419.78±22.70mg/100ml(P<0.01),差异有高度显著性。实验组服用地黄合剂后,血糖值从410.25±2739mg/100ml下降至313.51±29.39mg/100ml(P<0.05)差异有显著性。因而认为地黄合剂对于四氧嘧啶性糖尿病有显著的降血糖作用。     

福参的苷类成分

目的 从福参Angelica morii提取分离活性成分。方法 采用乙醇提取，溶剂萃取，大孔树脂、聚酰胺、硅胶柱层析，LH-20、重结晶等纯化，对福参饮片进行系统提取分离；运用波谱学方法及理化常数对照进行结构鉴定。结果 从正丁醇和水部分分离到6个苷类化合物，分别为升麻索苷(prim-O-glucosylcimifugin，Ⅰ)、紫花前胡苷(marmesinin，Ⅱ)、芹菜素7-O-β-D-葡萄糖苷(apigenin 7-O0-β-D-glucoside，Ⅲ)、木犀草素7-O-β-D-葡萄糖苷(1ute—olin 7-O-β-D-glucoside，Ⅳ)，umbeliferone 7-apiosylglucoside(V)和胡萝卜苷(daucosterol，Ⅵ)。结论 6个化合物均为首次该植物中分得；化合物Ⅲ首次从当归属中分得。