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.     

社区“5+1”糖尿病分阶段达标管理对2型糖尿病患者生存质量干预效果分析

目的 分析社区"5+1"糖尿病分阶段达标管理对2型糖尿病患者生存质量的干预效果及其影响因素，为提高患者生存质量提供依据。方法 采用分层整群抽样的方法在山西省、江苏省和宁夏回族自治区选择12个社区卫生服务中心，分别作为干预组（管理方式：社区"5+1"糖尿病分阶段达标管理）、对照组[管理方式：依据《国家基本公共卫生服务规范（2011年版）》的相关要求]，进行为期2年的随访观察。采用面对面问卷调查的方式，收集患者的人口学信息等基本信息；采用健康调查简表（SF-36）对患者在干预前后测量生存质量。采用SAS 9.4软件进行双重差分法以及多重线性回归模型分析。结果 基线时共纳入2 467名研究对象，终末时共1 924人接受了为期2年完整的随访管理。干预后，干预组、对照组患者生理健康维度（PCS）、心理健康维度（MCS）评分变化净差值分别为13.6分、29.8分。多重线性回归分析结果显示，影响患者PCS得分的主要因素有年龄、医保类型、基线PCS得分以及所在地区，影响患者MCS得分的主要因素有年龄、医保类型、基线MCS得分、是否合并高血压以及所在地区。结论 社区"5+1"糖尿病分阶段达标管理对2型糖尿病患者生存质量的干预效果较好。     

Influence of Fine Grains on the Bending Fatigue Behavior of Two Implant Titanium Alloys

By means of the ultrasonic surface impact (amplitude of 30 μm, strike number of 48,000 times/mm²), nanograins have been achieved in the surfaces of both Ti6Al4V(TC4) and Ti3Zr2Sn3Mo25Nb(TLM) titanium alloys, mainly because of the dislocation motion. Many mechanical properties are improved, such as hardness, residual stress, and roughness. The rotating–bending fatigue limits of TC4 and TLM subjected to ultrasonic impact are improved by 13.1% and 23.7%, separately. Because of the bending fatigue behavior, which is sensitive to the surface condition, cracks usually initiate from the surface defects under high stress amplitude. By means of an ultrasonic impact tip with the size of 8 mm, most of the inner cracks present at the zone with a depth range of 100~250 μm in the high life region. The inner crack core to TC4 usually appears as a deformed long and narrow α-phase, while the cracks in TLM specimens prefer to initiate at the triple grain boundary junctions. This zone crosses the grain refined layer and the deformed coarse grain layer. With the gradient change of elastic parameters, the model shows an increase of normal stress at this zone. Combined with the loss of plasticity and toughness, it is easy to understand these fatigue behaviors.     

晚期肺癌化疗患者医院感染的病原学与危险因素分析

目的研究晚期肺癌化疗患者发生医院感染的病原学特点,分析其危险因素,降低晚期肺癌化疗患者医院感染率。方法选择2012年1月-2015年12月收治的532例晚期肺癌化疗患者为研究对象,采集患者痰液或呼吸道分泌物标本进行细菌培养,应用SAS 9.3软件进行统计分析,并分析晚期肺癌化疗患者发生医院感染的危险因素。结果 125例晚期肺癌化疗患者发生医院感染,感染率为23.50%,其主要感染部位为呼吸道、胃肠道、口腔黏膜,分别占52.00%、15.20%、14.40%;共分离病原菌104株,其中革兰阴性菌51株占49.04%、革兰阳性菌30株占28.85%、真菌23株占22.11%;logistics回归显示,住院时间长、接受侵入性操作、使用抗菌药物是晚期肺癌化疗患者发生医院感染的危险因素。结论晚期肺癌化疗患者医院感染率较高,主要病原菌以革兰阴性菌为主,通过缩短患者住院时间、减少侵入性操作、合理使用抗菌药物等措施,降低晚期肺癌化疗患者医院感染的发生。     

Clinical analysis of peritoneal dialysis in the treatment of rapidly progressive glomerulonephritis

Objective To observe the clinical characteristics and prognosis of patients with rapidly progressive glomerulonephritis (RPGN) caused by lupus nephritis, antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis, or primary glomerulonephritis who were treated with peritoneal dialysis (PD) and then withdrew PD because of renal recovery. Methods Data of the above patients were retrospectively analyzed. The patients were diagnosed as RPGN and received PD therapy in Kidney Disease Center, the First Affiliated Hospital, College of Medicine, Zhejiang University from February 2009 to August 2018. The patients were divided into early withdrawal group (PD time≤183 days, n=24) and late withdrawal group (PD time＞183 day, n=24). The differences of clinical characteristics between the two groups were compared. The cumulative incidence of adverse events in both groups was analyzed using Kaplan-Meier curves. Cox proportional hazards model was used to analyze the risk factors influencing the prognosis of patients. Results Forty-eight RPGN patients were included. The median time of maintaining PD was 178(76, 378) days. Compared with the late withdrawal group, the patients in early withdrawal group had lower levels of urine volume, serum albumin and parathyroid hormone, and lower rates of gross hematuria and hypertension at the beginning of PD, and received higher rates of methylprednisolone impulse, combined immunosuppressive agents, and hemodialysis or continuous renal replacement therapy (all P＜0.05). At the time of PD withdrawal, the levels of serum creatinine, serum calcium, serum albumin and parathyroid hormone in the early withdrawal group were significantly lower than those in the late withdrawal group (all P＜0.05). The Kaplan-Meier curves showed that there was no significant difference in the cumulative survival of patients in both groups (log-rank test χ2=3.485, P=0.062). Cox regression analysis revealed serum creatinine≥209 μmol/L at the time of PD withdrawal was an independent risk factor for poor prognosis (HR=5.253，95%CI 1.757-15.702, P=0.003). Conclusions PD can be used for RPGN patients caused by lupus nephritis, ANCA-associated vasculitis and primary nephritis. Serum creatinine≥209 μmol/L at the time of PD withdrawal is an independent risk factor for poor prognosis.     

慕课在医学生假期课前预习中的应用探讨

高校医学生会利用假期时间对将要学习的科目进行预习,力求提前了解或掌握,以利于日后对知识的充分理解。预习对于医学科目学习有一定必要性,然而传统的假期预习模式常存在缺乏引导、效率难以提升等问题。目前,慕课在医学教育领域的应用有所发展。对于医学生,其自主学习的模式、课程设计等契合医学课程的预习需求和假期学习的特点,有助于提升医学生的学习能力和假期预习效果。医学生将慕课作为假期预习资源可有多种学习模式选择。慕课平台的功能拓展和学校教师的辅助可以有效深入慕课在医学生假期预习中的应用,为医学生带来更合理的假期学习安排。     

8种寄生虫病例分析

本文报道并分析8例寄生虫病例,其中包括脑裂头蚴病、眼部裂头蚴病、肺吸虫幼虫移行症、肺吸虫病、钩虫病、肝吸虫病、包虫病和广州管圆线虫病各1例。8例寄生虫病均有不同程度的误诊,其中6例在寄生虫抗体筛查检测阳性后得以确诊。因此,寄生虫病应引起临床医生的重视,抗体筛查有助于发现寄生虫病例。