Cross-sectional neurotoxicology study of lead-exposed cohort

Although the toxic effects of lead have been known for centuries, lead intoxication is still widespread in the United States. Without baseline tests of neuropsychological, neurobehavioral and neurophysiological testing it may be difficult to detect subtle changes in neurological function after lead exposure. This may be further confounded by partial chelation treatment and exposure to neurotoxic mixtures or inability to quantitate alcohol consumption. We undertook a cross-sectional study to address these problems in 24 exposed and 29 control subjects in a plant that manufactured electrical components using fritted leaded glass to coat capacitors and transistors. Potentially exposed workers had blood lead levels ranging between 3 micrograms/dL to 135 micrograms/dL. Industrial hygiene monitoring revealed the plant's air lead levels ranged from 61 micrograms/m3 to 1,700 micrograms/m3 in excess of OSHA permissible exposure limits of 40 micrograms/m3/10 hr day. Using a specially designed battery of neurophysiological, neurobehavioral and neuropsychological screening tests, we demonstrated a significant difference from controls in measures of psychomotor speed, motor strength and verbal memory. Although limited by the cross-sectional design, these findings support the hypothesis that the battery of neurophysiological, neuropsychological and neurobehavioral tests can detect a significant inter-group differences between lead-exposed and control subjects.     

Sample size for cohort studies in pharmacoepidemiology

OBJECT: Cohort studies in pharmacoepidemiology can result in a unique type of study, where subjects have complex types of exposure to drugs (with periods of non-exposure as well). The object of this paper is to explain how to calculate the sample size of such a study. METHOD: It is assumed that adverse events follow Poisson distributions in the two study groups. The null hypothesis is that the two groups have equal rates of disease. Formulae are provided to calculate the sample size required to significantly reject the null hypothesis. Sample size is given as the number of events, rather than the number of subjects entered. In a Poisson study, it is the ratio of the amount of person-years exposure in the two groups that is important to calculate sample size, rather than the actual amounts of exposure (or number of subjects in the study). Some examples are included.     

利奈唑胺致血小板减少的回顾性研究

目的探讨利奈唑胺对血小板的影响。方法以万古霉素为对照,采用回顾性队列研究方法,收集我院2009年1月至2012年4月住院感染患者215例,其中,利奈唑胺组(观察组)102例,万古霉素组(对照组)113例。比较2组治疗前后血小板减少的发生率。结果观察组和对照组的血小板发生率分别为40.2%和8.0%;利奈唑胺组发生血小板减少的相对危险度较高[RR=6.30,95%CI(2.69～14.77),P<0.01]。结论利奈唑胺致血小板减少的发生率显著高于万古霉素,临床使用利奈唑胺时应密切监测血小板变化。     

Exposure matrix development for the Libby cohort

The Libby, MT, cohort includes current and former residents with potential historical exposure to asbestos-contaminated vermiculite. This cohort includes individuals with a broad range of exposure experiences and work histories. While both occupational and nonoccupational exposure pathways were found to be relevant in recent investigations of health effects among this cohort, there has not been a comprehensive approach to characterizing these varied exposure pathways. Any approach toward assessing historical exposures among this population must account for three general categories: (1) occupational exposures, (2) residential exposures, and (3) exposures related to a variety of nonoccupational activities thought to be associated with vermiculite/asbestos exposure in this community. First, a job exposure matrix is commonly used in occupational epidemiology to assess historical worker exposures, allowing for the incorporation of numerous occupational categories and weighting factors applied to specific jobs for different time periods. Second, residential exposures can best be quantified by integrating individuals' residential histories with data on environmental asbestos contamination in the community. Previous soil or sediment sampling as well as air modeling could inform estimates of time- and spatial-dependent exposure concentrations for a residential exposure matrix. Finally, exposure opportunities due to nonoccupational activities could be weighted by factors such as time, geography, environmental sampling, and an assessment of the relative importance for each pathway. These three matrices for occupational, residential, and activity exposure pathways could be combined or used separately to provide a more comprehensive and quantitative, or semiquantitative, assessment of individual exposure in future epidemiological studies of this cohort.     

帕金森病治疗学DATATOP方案扩展

以帕金森病(PD)治疗学 DATATOP 方案为动机,应用 Actovegin,levodopa,tocopherol 和 Amantadine 治疗了18例 PD 人。给药方法以 Actovegin 1200mg一日一次静脉输入,连用1个月,同时服用 Levodopa 和 tocopherol。levodopa 给药分剂量调整期和剂量维持期,起始剂量为0.25g,tidPo,然后缓慢渐增一般达1.8-2.2g 时有7全出现副作用,此时 levodopa 不再加量,而加用 Amantadine 糖浆,直到症状改善而又不出现副作用为止,结果见到早、中、晚期 PD,良性、恶性 PD 以及震颤、PLGD 为主型 PD 均有效,总有效率在88.8%,且副作用较少,病人易于耐受,主观上也愿意接受,该文并以此讨论了有效的可能作用机理。     

比较效果研究常用方法之二：队列研究设计

队列研究是循证医学证据等级中仅次于随机对照试验的临床研究证据,本质上属于观察性研究,也是常用的比较效果研究的研究类型。队列研究既容易满足伦理的要求,也有着较强的外部真实性,同时还能验证因果关系,比干预性研究的典型代表随机对照试验更贴近于临床实际。从比较效果研究角度介绍队列研究用于疗效评价时暴露的定义、对照的选择、结局指标的选取、样本含量计算等设计要点及其优缺点,同时讨论了研究过程中可能存在的偏倚及控制方法,并提供了队列研究的方法学质量评价标准和报告规范。     

A clozapine cohort: outcome and issues of concern

A retrospective case-note follow-up study of 22 patients who had been registered with the Clozapine Patient Monitoring Service was undertaken by the patients' former consultant 16 months after the consultant had left the post. Only 17 per cent of the patients remained on clozapine compared with the UK figure of 58 per cent overall. Six patients had clozapine withdrawn within 6 weeks of the consultant's departure, rationale for the decision not appearing in the case notes. Outcome of patients who stopped clozapine was generally poor. It is recommended that guidelines for effective use of clozapine should be available and should cover appropriate reasons for withdrawal of treatment. © 1997 John Wiley & Sons, Ltd.     

Impaired renal function and atherosclerosis in a Pakistani cohort

ABSTRACT

Objective: To investigate the relationship of creatinine and calculated glomerular filtration rate (GFR) with coronary arterial disease (CAD) in Pakistani patients.

Subjects: Four hundred individuals with chest pain; 200 with angiographic disease matched with 200 without occlusive disease.

Design: A prospective case-control study.

Setting: A tertiary referral cardiology unit in Pakistan.

Results: Impaired renal function as estimated by calculated GFR was common in this population. Creatinine and glomerular filtration rate, as calculated by the Cockcroft–Gault (CG) and Modification of Diet in Renal Disease (MDRD) formulae, were associated with CAD and atherosclerotic burden in Pakistani patients. Calculation of creatinine clearance, correcting for age, sex and body mass index, showed that clearance was 81 (17–257)?mL/min/1.73?m² in patients with CAD compared with 88 (23–167)?mL/min/1.73?m² in controls with a significant number of patients (18.5 vs. 6.5%; RR = 2.85; p < 0.001) showing significant renal impairment (< 60?mL/min/1.73?m²) by CG and more by the MDRD equation (26 vs. 9%; RR = 2.88; p < 0.001). The unadjusted odds ratios for CAD for a GFR < 60?mL/min/1.73?m² were 3.66 (1.87–7.16) and 3.29 (1.81–6.01), respectively and, after adjustment for diabetes, smoking, insulin resistance, inflammation and apolipoprotein A1, 1.04 (1.02–1.09) and 1.04 (1.02–1.09), respectively.

Conclusions: Impaired renal function is common in Pakistani patients with coronary arterial disease and is strongly associated with a risk of atherosclerosis independent of insulin resistance.