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.     

创伤性膈疝21例临床分析

我院自１９８９年３月至１９９５年１０月手术治疗２１例创伤性膈疝，２１例疝愈。 发病机理与胸腹腔压力差、腹腔脏器冲击膈肌及胸腔负压有关。同时简要介绍了创伤性膈疝的诊断和治疗。     

中国已婚育龄妇女分娩保健服务的状况与变化研究

目的:分析我国已婚育龄妇女分娩保健服务状况及其变化。方法:对全国31个省(直辖市、自治区)抽取的调查前三年有生育史的1962名已婚育龄妇女进行问卷调查,结合1997年全国人口与生殖健康调查资料,对两次调查前三年有生育史妇女最近一次活产的分娩保健服务状况进行比较分析。结果:①与1997年调查前三年相比,2001年调查前三年育龄妇女的入院分娩率增加,家庭分娩的比例明显减少;②农村妇女家庭分娩比例明显降低,由1997年调查时的61·41%降为2001年调查时的40·78%,1998~2000年间,92·54%城镇妇女接受分娩保健服务,农村妇女家庭分娩比例高出城镇7·4倍,为40·78%;③分娩保健服务在各地区发展不平衡,东部和中部地区发展快,西部地区,尤其是西南地区发展相对较慢,1998~2000年间,西部地区妇女中,一半以上在家分娩,西部地区农村家庭分娩妇女一半以上由家人接生,约为东部和中部地区的6倍;④少数民族妇女家庭分娩和由家人接生的比例明显高于汉族妇女;⑤随着文化程度和经济收入的增加育龄妇女对分娩保健服务的利用增加,文盲、经济收入低的妇女家庭分娩比例和由家人接生的比例非常高。结论:我国分娩保健服务状况在改善,但发展极不平衡,西部地区农村的分娩保健服务急待提高。应加强对西部地区分娩保健服务的支持力度,研究制定应对策略,加强对西部农村接生人员的专业技术培训。     

Association of psychological and physiological measures of stress in health‐care professionals during an 8‐week mindfulness meditation program: mindfulness in practice

Work stress, burnout, and diminished empathy are prevalent issues for health‐care professionals. Mindfulness meditation (MM) is one commonly used strategy to manage stress. Measuring salivary cortisol allows for the assessment of serum cortisol level, a known stress level indicator. This study evaluated the association of subject‐reported stress symptoms and salivary cortisol in health‐care professionals, in an 8‐week MM program, with data collected prospectively at baseline and 8 weeks after program completion. Questionnaires [Profile of Mood States—Short Form (POMS‐SF), Maslach Burnout Inventory (MBI), and Interpersonal Reactivity Index (IRI)] measured mood, burnout and empathy. A paired t‐test between groups for pre/post‐salivary cortisol yielded no significant change. The POMS‐SF was most sensitive to change (mean increase 12.4; p = 0.020). Emotional exhaustion, measured in the MBI, was also affected by MM (mean decrease 4.54; p = 0.001). Changes in empathy may not have been captured due to either absence of effect of MM on empathy, subject number or scale sensitivity. Baseline and 8‐week correlations between salivary cortisol and survey results, and correlations between changes in these measures, were weak and not statistically significant. Nevertheless, psychometric results present a strong case for additional clinical trials of MM to reduce stress for health‐care professionals. Copyright © 2005 John Wiley & Sons, Ltd.     

OVERHEATING IN BED AS AN IMPORTANT FACTOR IN MANY COMMON DERMATOSES

Background. Extensive questioning of patients with a wide variety of skin disorders led to the impression that nocturnal overheating was probably an important factor in the initiation and the perpetuation of many skin disorders. Methods. In order to test the hypothesis, 12 “clean-skinned” subjects (6M/6F) aged 18 to 45 years were monitored electronically every 30 seconds during an 8 hour sleep period (2300 to 0700 hours), sleeping under a standard 10 tog duvet. Results. All the subjects were too hot by 3 to 4°C. All showed changes in their EEG patterns with reduced REM sleep, increased awakenings, and all showed changes in their sleep stage patterns. In addition, they all showed evidence of increased sweating in the “heat-sink” area. Conclusions. The mechanisms where by such changes could be implicated in the precipitation and perpetuation of skin disease are discussed. “Lifestyle” modification as a very effective, noninvasive, therapeutic regime is recommended. Further research along these lines would probably be very valuable and instructive.     

头孢噻肟在恶性血液病合并感染患者体内杀菌效价及临床疗效比较

目的 对比观察头孢噻肟（ＣＴＸ）与其他两种抗菌药物治疗方案对３０例血液病合并感染患者杀 菌活性（ＳＢＡ）及临床疗效。方法ＳＢＡ采用微量稀释法测定，临床疗效根据临床治疗登记表按三 级标准判定。结果与结论 头孢噻肟的临床反应最佳，杀菌作用时间维持较长，但对绿脓假单胞 菌和阴沟肠杆菌杀菌作用较差；呱拉西林（ＰＩＰ）与阿米卡星（ＡＮ）方案的抗菌谱广，但ＰＩＰ杀菌 作用时间较短，可考虑缩短给药间期，而ＡＮ可按一日一次给全日量的方案，以提高疗效减少不 良反应；头孢哌酮（ＣＰＺ）可主要用于绿脓假单胞菌感染，也可用于其它细菌的混合感染，但给药 间隔时间以一日三次为宜。     

Heterogeneity of cerebral vasoreactivity in preterm infants supported by mechanical ventilation

The reaction of cerebral blood flow to acute changes in arterial carbon dioxide pressure (PaCO2) and mean arterial blood pressure was determined in 57 preterm infants supported by mechanical ventilation (mean gestational age 30.1 weeks) during the first 48 hours of life. All infants had normal brain sonograms at the time of the investigation. In each infant, global cerebral blood flow was determined by xenon-133 clearance two to five times within a few hours at different levels of PaCO2. Changes in PaCO2 followed adjustments of the ventilator settings. Arterial oxygen pressure was intended to be kept constant, and mean arterial blood pressure fluctuated spontaneously between measurements. The data were analyzed by stepwise multiple regression, with changes in global cerebral blood flow, PaCO2, mean arterial blood pressure, and postnatal age or intracranial hemorrhage used as variables. In infants with persistently normal brain sonograms, the global cerebral blood flow-carbon dioxide reactivity was markedly lower during the first day of life (mean 11.2% to 11.8%/kPa PaCO2) compared with the second day of life (mean 32.6/kPa PaCO2), and pressure-flow autoregulation was preserved. Similarly, global cerebral blood flow-carbon dioxide reactivity and pressure-flow autoregulation were present in infants in whom mild intracranial hemorrhage developed after the study. In contrast, global cerebral blood flow reactivity to changes in PaCO2 and mean arterial blood pressure was absent in infants in whom ultrasonographic signs of severe intracranial hemorrhage subsequently developed. These infants also had about 20% lower global cerebral blood flow before hemorrhage, in comparison with infants whose sonograms were normal, a finding that suggests functional disturbances of cerebral blood flow regulation. Several perinatal factors were tested, but only birth after abruptio placentae was related to subsequent periventricular hemorrhage (p = 0.037).