Smallpox models as policy tools

Mathematical models can help prepare for and respond to bioterrorism attacks, provided that their strengths and weaknesses are clearly understood. A series of initiatives within the Department of Health and Human Services brought modelers together with biologists and epidemiologists who specialize in smallpox and experts in bioterrorism response and health policy and has led to the parallel development of models with different technical approaches but standardized scenarios, parameter ranges, and outcome measures. Cross-disciplinary interactions throughout the process supported the development of models focused on systematically comparing alternate intervention strategies, determining the most important issues in decision-making, and identifying gaps in current knowledge.     

Value of the Diagnostic Sodium Calcium Edetate Mobilization Test as a Criterion of Lead Absorption

Among the laboratory tests available for the follow-up of lead-exposedworkers, the EDTA mobilization test is presently underestimatedin the diagnosis of lead intoxication. The authors present theresults of regression comparison between the urinary lead excretion3 h (PbU 3) or 6 h (PbU 6) after EDTA injection and blood lead(PbB), urinary aminolaevulinic acid (ALAU) and urinary lead(PbU). The results were collected from 133 medical examinationsof workers exposed to lead, who put in a claim for compensationto the ‘Fund of Occupational Diseases’ in Belgium.On the basis of the regression curves, PbU 3 and PbU 6 limitvalues are calculated for different cut-off values of PbB inexcessive lead absorption and lead intoxication. For each ofthese values the ‘sensitivity’, ‘specificity’and ‘validity’ are calculated. As a result the authorsstill consider the EDTA mobilization test as a valuable parameterin the diagnosis of lead absorption. Requests for reprints should be addressed to: Dr D. Lahaye, Fund of Occupational Diseases, Sterrenkundelaan 1, 1030, Brussels, Belgium     

Infection as a likely risk factor for ischemic stroke

This review presents recent informations concerning the role of viral and bacterial (especially Helicobacter pylori and Chlamydia pneumoniae) infections in the development of ischaemic stroke. Among possible pathogenic pathways that link infections and stroke, the special attention is paid to the coagulation abnormalities and immunological reactions.     

诊断试验证实偏倚校正方法的比较研究

目的探讨两阶段两分类诊断试验存在证实偏倚时灵敏度和特异度的校正方法并进行比较。方法运用实例和模拟数据说明传统方法灵敏度和特异度的有偏估计,并运用最大似然估计和贝叶斯估计对灵敏度和特异度进行校正。结果传统方法计算的灵敏度和特异度存在偏倚,最大似然法和贝叶斯方法虽然均可校正估计偏倚,但是后者计算的可信区间比前者窄。结论在对诊断试验证实偏倚进行校正时,若有良好的先验信息,贝叶斯方法所获的结果更精确。     

Diagnostic Accuracy of the E-Plate Serum Antibody Test Kit in Detecting Helicobacter pylori Infection Among Japanese Children

Background

A number of noninvasive diagnostic tests are available to detect Helicobacter pylori infection. Data on serologic testing of children are lacking, however, and thus it remains unclear whether the serology cutoff points used for adults are appropriate for children.

Methods

Serum and stool samples were obtained from 73 children who visited 5 hospitals in Japan between March 1993 and December 2009. Analysis of stool samples was carried out using an H pylori stool antigen enzyme-linked immunosorbent assay (HpSA ELISA), and serum antibodies to H pylori were examined using an antibody determination kit (E-Plate Eiken H pylori antibody). The validity of the serologic test was evaluated based on its sensitivity, specificity, and receiver operating characteristics curve.

Results

Of the 73 children included in this study, 34 were HpSA-positive and 39 were negative. Among the 34 HpSA-positive patients, 32 were IgG-positive and 2 were IgG-negative. Of the 39 patients who were HpSA-negative, 38 were IgG-negative and 1 was IgG-positive. The sensitivity, specificity, and positive likelihood ratio for IgG antibody testing were 91.2%, 97.4%, and 35.6, respectively, based on the recommended adult cutoff point of 10 U/ml. Among children, use of cutoff points in the range of 7 to 9 U/ml yielded optimal values for sensitivity and specificity, as well as a positive likelihood ratio.

Conclusions

The performance of the E-plate anti-H pylori IgG antibody test was comparable to that of the stool antigen test and is therefore suitable for epidemiologic studies of H pylori infection in large samples.Key words: Helicobacter pylori, serologic test, validity, stool antigen test     

神经心理测试对问题儿童诊断意义的研究

目的：探讨神经心理测试对问题儿童的诊断意义。方法：对1540名儿童进行神经心理测试和问卷调查，获得神经心理测试常模，并应用诊断试验学原理评价专科门诊问题儿童。结果：神经心理测试常模有年龄差异（P＜0．05）。神经心理测试对问题儿童诊断有较高的灵敏度和特异度。结论：神经心理测试结果体现了儿童神经心理发育的特点。神经心理测试对问题儿童的诊断有临床意义。     

具有协变量或干扰因素的诊断试验数据的ROC分析

目的 探讨具有协变量或干扰因素的诊断试验的评价问题。建立相应的统计模型及分析方法。方法 基于ROC分析给出变量ROC模型，采用有序logistic连续函数，利用SAS软件进行参数估计，得到有协为量情况下的ROC曲线方程及曲线下面积。文中结合检测动脉硬化的数据，说明了其用法。结果 采用文中给出的方法，可以有效地扣除协变量的影响，准确地评价诊断的作用。结论 本文提供的方法能够有效地解决诊断试验中具有干扰因素影响的问题。     

Human Plasmodium knowlesi Infection Detected by Rapid Diagnostic Tests for Malaria

We describe a PCR-confirmed case of Plasmodium knowlesi infection with a high parasitemia level and clinical signs of severe malaria in a migrant worker from Malaysian Borneo in the Netherlands. Investigations showed that commercially available rapid antigen tests for detection of human Plasmodium infections can detect P. knowlesi infections in humans.