妊娠期糖尿病并发子痫前期的脐动脉血流及围产结局探讨

目的:探讨妊娠期糖尿病(GDM)并发子痫前期(PE)的脐动脉血流和围产结局.方法:选择产妇134例,分为GDM组65例、PE组45例、GDM+ PE组24例.收集三组患者年龄、分娩孕周、孕前体重指数(BMI)、脐动脉血流阻力指数(RI)、搏动指数(PI)、收缩期最大血流速度峰值/舒张末期血流速度(S/D)及围产结局.结果:GDM+ PE组患者年龄显著高于另外两组,分娩孕周显著小于另外两组;GDM+ PE组的PI值、S/D值、RI值均显著高于GDM组和PE组,而GDM组和PE组之间三项脐动脉血流指标比较无统计学差异.GDM+ PE组新生儿出生体重显著低于GDM组和PE组,胎儿生长受限(FGR)、早产、转NICU比例、新生儿1 min Apgar评分显著高于GDM组和PE组;GDM组与PE组在新生儿出生体重、FGR、早产、转NICU比例、新生儿1 minApgar评分比较无统计学差异.结论:GDM合并PE患者脐血流指标明显升高,易发生不良围产结局,应加强孕期监护,积极防治,改善母儿结局.     

前白蛋白在孕妇血清及胎盘组织的表达与妊娠期高血压疾病严重程度的关系

目的探讨在妊娠期高血压疾病、子痫前期(PE)、PE合并胎儿宫内生长受限(FGR)的孕妇血清及胎盘组织中，前白蛋白(PBA)表达及其临床意义。 方法选择2014年1月至2016年1月，在首都医科大学附属北京潞河医院进行常规产前检查，并采取剖宫产术分娩的98例罹患不同程度妊娠期高血压疾病的单胎妊娠孕妇为研究对象。其中，被诊断为妊娠期高血压疾病者为31例、单纯PE者为33例、PE合并FGR者为34例，将其分别纳入妊娠期高血压疾病组、单纯PE组、PE合并FGR组。单纯PE组与PE合并FGR组的67例孕妇中，早发型PE为30例，晚发型PE为37例。选择同期于收集上述病例的同一家医院进行常规产前检查，并采取剖宫产术分娩的36例正常足月单胎妊娠孕妇作为研究对照，纳入对照组。分别采用酶联免疫吸附试验法与免疫组化法，对分娩前4组孕妇的血清及胎盘组织PBA表达进行检测。4组孕妇血清PBA比较，采用单因素方差分析，进一步两两比较，采用最小显著性差异(LSD)法。4组孕妇胎盘组织PBA表达呈阴性、弱阳性、中度阳性、较强阳性、强阳性率比较，采用Kruskal-Wallis H秩和检验，进一步两两比较，采用Mann-Whitney U检验，并采用Bonferroni法调整检验水准(α′＝0.05/6＝0.008)。本研究遵循的程序符合首都医科大学附属北京潞河医院人体试验委员会制定的标准，经过该伦理委员会批准(批准文号：2018LH-KS-025)，并与所有受试者签署临床研究知情同意书。 结果①4组孕妇年龄、孕次、产次、孕前人体质量指数(BMI)等一般临床资料比较，差异均无统计学意义(P>0.05)。②4组孕妇平均动脉压、24 h尿蛋白定量、分娩孕龄、新生儿出生体重、血清PBA比较，差异均有统计学意义(F＝233.773、222.081、113.597、214.420、90.147，P<0.001)。对4组孕妇血清PBA进一步进行两两比较的结果显示，妊娠期高血压疾病组、单纯PE组、PE合并FGR组孕妇血清PBA，均显著低于对照组，单纯PE组、PE合并FGR组孕妇血清PBA，均显著低于妊娠期高血压疾病组，PE合并FGR组孕妇血清PBA，显著低于单纯PE组，并且差异均有统计学意义(P<0.05)。③PBA表达于胎盘绒毛滋养细胞细胞质，为粗大棕褐色颗粒。对照组孕妇胎盘组织中，PBA呈较强阳性和(或)强阳性表达；单纯PE组及PE合并FGR组孕妇胎盘组织中，PBA呈阴性或弱阳性表达；妊娠期高血压疾病组，则呈中度阳性表达。④4组孕妇胎盘组织PBA表达呈阴性、弱阳性、中度阳性、较强阳性、强阳性率总体比较，差异有统计学意义(χ²＝39.405，P＝0.013)。进一步进行两两比较的结果显示，与对照组相比，单纯PE组、PE合并FGR组孕妇胎盘组织PBA减低，并且差有统计学意义(Z＝3.416、4.846，P<0.001)；与妊娠期高血压疾病组相比，PE合并FGR组孕妇胎盘组织PBA减低，并且差异有统计学意义(Z＝2.829，P＝0.004)。⑤早发型PE孕妇血清及胎盘组织PBA，均较晚发型PE低，并且差异均有统计学意义(t＝3.160、P＝0.002，χ²＝8.201、P<0.001)。 结论PBA在妊娠期高血压疾病、PE、PE合并FGR孕妇血清及胎盘组织中，均呈低表达，在早发型PE孕妇中尤其明显，并且PBA随着妊娠期高血压疾病严重程度增加，而降低。     

胎盘源性肿瘤坏死因子-α和肌肉生长抑制素对子痫前期患者及胎儿发育的影响

目的 探讨胎盘源性肿瘤坏死因子（TNF）-α和肌肉生长抑制素（MSIN）水平对子痫前期（PE）的发病机制及胎儿发育的影响.方法 选择2008年10月至2013年10月住院分娩的孕妇120例为研究对象.其中择期行剖宫产的足月健康孕妇40例（正常对照组）、PE且胎儿发育正常的孕妇40例（PE组）、PE合并胎儿生长受限（FGR）的孕妇40例（PE＋FGR组）.采用免疫组化过氧化物酶法检测TNF-α和MSIN蛋白在各组胎盘组织中的定位,运用实时荧光定量PCR技术及蛋白印迹法检测各组胎盘组织中TNF-α和MSIN mRNA和蛋白的表达.结果 TNF-α主要定位在胎盘的血管周围间质、蜕膜细胞、滋养层细胞,MSIN主要定位在胎盘的血管周围间质、蜕膜细胞及终末绒毛.TNF-α和MSIN mRNA的表达量在PE组为3.65±0.86,1.80±0.32;在PE＋FGR组为3.88±0.71,2.01±0.55;在正常对照组为1.32±0.21,0.77±0.39.相对于正常对照组,PE组和PE＋FGR组TNF-α mRNA和MSIN mRNA表达均显著升高,差异有统计学意义（P＜0.01）.PE组和PE＋FGR组比较,差异有统计学意义（P＜0.05）.TNF-α和MSIN蛋白的表达在正常对照组为0.56±0.13,1.31±0.23;在PE组为1.67±0.25,1.55±0.34;在PE＋FGR组为2.78±0.41,3.07±0.51.相对于正常对照组,PE组和PE＋FGR组TNF-仅蛋白和MSIN蛋白表达均显著升高,差异有统计学意义（P＜0.01）.PE组和PE＋FGR组比较,差异有统计学意义（P＜0.05）.结论 胎盘源性TNF-α和MSIN对于PE的发病及胎儿的正常发育具有重要的作用,检测胎盘源性TNF-α和MSIN为PE的诊断及治疗提供了相关的应对策略.     

重度子痫前期合并胎儿宫内生长受限孕妇血清PLGF、Hcy及IGF-1水平变化及其与妊娠结局的相关性研究

目的研究重度子痫前期(PE)合并胎儿宫内生长受限(FGR)孕妇血清胎盘生长因子(PLGF)、同型半胱氨酶(Hcy)、胰岛素生长因子-1 (IGF-1)水平变化及其与妊娠结局的相关性。方法将2017年1月-2018年12月间该院收治的47例重度PE合并FGR患者纳为研究组,30例健康孕妇为对照组,比较两组血清PLGF、Hcy及IGF-1水平,根据妊娠结局将研究组患者分为结局良好组(n=19)与结局不良组(n=28),比较两者血清PLGF、Hcy及IGF-1水平,分析血清PLGF、Hcy及IGF-1与重度PE合并FGR患者妊娠结局的关系。结果研究组与对照组血清PLGF、IGF-1、Hcy水平比较,差异有统计学意义(P0. 05);研究组生产不良结局发生率显著高于对照组(P0. 05);结局良好组血清PLGF、IGF-1、Hcy水平与结局不良组比较,差异有统计学意义(P0. 05);受试者工作特征(ROC)曲线分析结果显示,血清PLGF、Hcy及IGF-1在预测重度PE合并FGR者不良妊娠结局中的临界值、灵敏度、特异度分别为169. 13 pg/ml、96. 40%、89. 50%,15. 45μmol/L、85. 70%、89. 50%,173. 52μg/L、96. 43%、89. 47%。结论重度PE合并FGR患者不良生产结局发生率较高,而患者血清PLGF、Hcy及IGF-1水平与其妊娠不良结局间存在一定关系,连续监控以上指标在预测患者妊娠结局中具有一定意义。     

双胎妊娠并发子痫前期妊娠结局及危险因素分析

目的：探究双胎妊娠并发子痫前期(PE)妊娠结局及其相关危险因素。方法：回顾性选取本院2021年5月-2022年9月收治的55例双胎妊娠并发PE孕妇(110例新生儿)纳入PE组，双胎妊娠正常孕妇55例(110例新生儿)纳入非PE组。比较两组一般资料、妊娠结局，分析双胎妊娠孕妇并发PE的危险因素。结果：PE组孕前体质指数(BMI)(30.7±3.5 kg/m²)大于正常组(28.5±2.9 kg/m²),辅助生殖技术(ART)受孕、单绒毛膜性双胎及贫血占比均高于正常组，血红蛋白、血清白蛋白、血小板水平均低于正常组；PE组早产(65.5%)、产后出血(12.7%)发生率均高于正常组(45.5%、1.8%);新生儿平均体重(2.4±0.4 kg)低于正常组(2.6±0.5 kg),低体重儿占比(58.2%)高于正常组(44.6%)(均P<0.05)。BMI≥24 kg/m²、ART受孕及单绒毛膜性均是导致双胎妊娠孕妇并发PE的危险因素(P<0.05)。结论：并发PE孕妇贫血及早产、产后出血、低体重儿等不良结局发生率升...     

HtrA1在子痫前期合并胎儿生长受限者胎盘及血清中的表达

目的探讨高温需求因子A1（HtrA1）在子痫前期合并胎儿生长受限（PE-FGR）患者胎盘组织及血清中的表达及意义。方法利用免疫组化SABC法检测正常妊娠者100例为对照组,子痫前期（PE）组83例及PE—FGR组17例胎盘组织中HtrA1蛋白表达,同时利用E1isa法分别检测晚孕期28^＋1-32周、32^＋1-36周、I〉36^＋13个时间段内血清HtrA1浓度。结果PE—FGR组预后较差,多为早发型子痫前期。HtrA1在对照组、PE组、PE—FGR组胎盘中的表达逐渐升高（平均灰度表达分别为152．69±4．11、156．03±5．07,165．82q-3．20）,任意2组间差异均有统计学意义（t=2．974～5．688,均P〈0．05）。仅28^＋1-32周间PE组及PE．FGR组血清中HtrA1水平（分别为42．66±2．24,47．32-I-3．22）显著高于对照组（28．18±2．40）（t分别为8．38、9．37,均P〈0．05）,PE组与PE-FGR组间无显著差异（t=2．562,P〉0．05）。结论HtrA1可能参与PE—FGR的发生,孕28“～32周血清中HtrA1高表达可能预示着PE及PE—FGR的发生。     

妊娠期高血压疾病患者血清sFlt-1、sEng水平及预测胎儿生长受限价值

目的：妊娠期高血压疾病患者血清人可溶性FMS样酪氨酸激酶1(sFlt-1)、可溶性内皮因子(sEng)水平变化及对胎儿生长受限(FGR)的预测价值。方法：收集2020年1月-2022年6月在本院诊断并分娩的妊娠期高血压疾病患者86例(观察组),根据妊娠结局分为FGR组(25例)与非FGR组(61例);另选产前检查正常孕产妇86例为对照组，比较两组及FGR组与非FGR组血清sFlt-1、sEng水平，受术者工作特征曲线(FGR)分析血清sFlt-1、sEng对FGR预测效能。结果：观察组血清sFlt-1(5358.16±52.25 pg/ml)、sEng(37.33±3.65 ng/L)水平均高于对照组(4166.01±52.99 pg/ml、33.69±4.11 ng/L),且观察组FGR组患者水平高于非FGR组(均P<0.05);血清sFlt-1、sEng水平联合检测对FGR诊断准确率(83.7%)显著高于单独检测(67.4%、73.3%),诊断曲线下面积(0.871)高于单独检测(0.792、0.778)。结论：妊娠期高血压疾病患者血清sFlt-1、sEng水平升高，且联合检...     

妊娠期糖尿病并发子痫前期的危险因素及妊娠结局分析

目的探讨妊娠期糖尿病(GDM)并发子痫前期(PE)的危险因素及其妊娠结局。方法选取2013年1月-2016年6月在该院及苏州大学附属第一人民医院分娩的50例单纯GDM患者为对照组,50例GDM并发PE患者为观察组,对比两组患者的体重指数(BMI)、甘油三酯(TG)、总胆固醇(TC)、空腹血糖(FPG)、糖化血红蛋白(HbA1c)、尿酸(UA)、脂质运载蛋白2(LCN-2)、同型半胱氨酸(Hcy)、乳酸脱氢酶(LDH)、碱性磷酸酶(ALP),并采用多元Logistic回归分析其危险因素,比较产后出血、剖宫产、早产、胎儿窘迫、胎膜早破、羊水量情况、新生儿体重和巨大儿发生率。结果观察组患者HbA1c、LDH及ALP与对照组比较,差异无统计学意义(P0.05);观察组患者BMI、TG、TC、FPG、UA、LCN-2、Hcy水平均明显高于对照组(P0.05),进一步多元Logistic回归分析显示,BMI、FPG及Hcy是GDM并发PE的危险因素(OR=1.051,1.234,1.117)。观察组患者的产后出血量、剖宫产、早产、胎儿窘迫及羊水量过少发生率明显高于对照组(P0.05),而两组胎膜早破、新生儿体重及巨大儿发生率比较,差异无统计学意义(P0.05)。结论 GDM并发PE患者的影响因素较多,其中BMI、FPG及Hcy是其危险因素,GDM并发PE可增加不良妊娠结局的发生率。     

联合检测D-二聚体、Hcy及hs-CRP与子痫前期并发DIC的相关性研究

目的探讨D-二聚体(D-dimer,D-D)、同型半胱氨酸(homocysteine,Hcy)和超敏-C反应蛋白(high-sensitivity CRP,hs-CRP)联合检测与子痫前期(Preeclampsia,PE)并发弥散性血管内凝血(Disseminated Intravascular Coagulation,DIC)的相关性。方法选取107例子痫前期患者(PE组),其中31例为重度子痫前期并发DIC患者(DIC组),39例为重度子痫前期患者(重度PE组),37例为轻度子痫前期患者(轻度PE组),110例正常妊娠孕妇作为对照组,分别检测D-二聚体、Hcy和hs-CRP,并用SPSS 19.0软件对结果进行分析比较。结果 PE组与对照组比较、DIC组与重度PE组和轻度PE组相比较、重度PE组与轻度PE组比较,D-二聚体、Hcy和hs-CRP差异均有统计学意义(P<0.01)。PE组、DIC组D-二聚体与Hcy及hs-CRP呈正相关(r=0.758、0.795,P<0.01)、(r=0.839、0.822,P<0.01),且D-二聚体、Hcy及hs-CRP浓度与PE病情轻重呈正相关(r=0.481、0.731、0.548,P<0.01)。结论 D-二聚体、Hcy及hs-CRP升高与子痫前期患者血管内皮损伤存在密切的关系,联合检测对了解子痫前期病情发展、预后判断及预防子痫前期并发DIC具有重要的临床指导意义。     

早发型重度子痫前期合并胎儿生长受限孕妇凝血指标的变化及临床意义

目的探讨早发型重度子痫前期(EOSP)合并胎儿生长受限(FGR)孕妇体内凝血指标变化,分析临床意义。方法选取2017年6月-2018年6月浙江萧山医院收治105例EOSP患者,回顾性分析检查资料,按照胎儿生长状态将有FGR和无FGR的患者分别纳入EOSP-FGR组(59例)和EOSP组(46例)。比较两组孕妇脐动脉血流变化、凝血指标水平、血脂与血小板水平、母婴结局。结果两组患者脐动脉血流指标,凝血指标,胆固醇(TC)、三酰甘油(TG)、血小板计数(PLT)、血小板平均分布宽度(PDW)、血小板平均体积(MPV),剖宫产、新生儿窒息、贫血、心脏发育不全、新生儿畸形、新生儿体质量偏低、入住NUCU、Apgar评分、新生儿住院时间比较差异均有统计学意义(均P0.05)。结论 EOSP并发FGR患者血液高凝状态越严重,母婴预后越差,可以依据患者凝血状态进行针对性干预,以改善母婴预后。     

Calcium intake in the elderly: validation of a dietary questionnaire

Epidemiological studies of calcium and osteoporosis have been hampered by the lack of a suitable tool for assessing calcium intake. This report describes a new frequency and amount questionnaire for measuring present and past calcium intake in the elderly. The validity of the questionnaire was tested against two commonly used standards of dietary assessment, five-day duplicate diets and seven-day weighed dietary inventories. The resulting correlation coefficients were, respectively, r = 0.76 and r = 0.69, while that for repeatability was r = 0.84. Furthermore, the questionnaire categorized subjects into thirds of the distribution of intake with almost no gross misclassification. It is suggested that the present findings may be extended to the majority of normal, healthy elderly subjects, implying wide application for the questionnaire in the assessment of calcium intake in the elderly.     

The occurrence of antimicrobial substances in toilet,sink and shower drainpipes of clinical units: A neglected source of antibiotic residues

Antibiotics represent one of the most important drug groups used in the management of bacterial infections in humans and animals. Due to the increasing problem of antibiotic resistance, assurance of the antibacterial effectiveness of these substances has moved into the focus of public health. The reduction in antibiotic residues in wastewater and the environment may play a decisive role in the development of increasing rates of antibiotic resistance. The present study examines the wastewater of 31 patient rooms of various German clinics for possible residues of antibiotics, as well as the wastewater of five private households as a reference.To the best of our knowledge, this study shows for the first time that in hospitals with high antibiotic consumption rates, residues of these drugs can be regularly detected in toilets, sink siphons and shower drains at concentrations ranging from 0.02?μg·L^?1 to a maximum of 79?mg·L^?1. After complete flushing of the wastewater siphons, antibiotics are no longer detectable, but after temporal stagnation, the concentration of the active substances in the water phases of respective siphons increases again, suggesting that antibiotics persist through the washing process in biofilms. This study demonstrates that clinical wastewater systems offer further possibilities for the optimization of antibiotic resistance surveillance.     

Self-reported health problems among Swedish miners one year after unemployment

Unemployment is considered to be a public health concern sincedeterioration in the health of the unemployed is often anticipated.However, for some groups, such as miners, unemployment mightimprove health due to a cessation of potentially harmful occupationalexposures. This study evaluates the health of 79 miners in oneSwedish iron-ore mine, and 226 age-matched controls from thegeneral population, during one year after the closure of themine. The participants received a questionnaire regarding medicalhistory and subjective symptoms at the beginning of the studyperiod, and after one year. Statistically significant negativeeffects on self-reported health attributable to unemploymentwere not found, although neuropsychiatric symptoms were morecommon among the unemployed miners. The miners reported a statisticallysignificant improvement in grip force (p=0.031). They had asignificantly higher prevalence of symptoms associated withmining related exposures when compared with the population controls;pain in the upper extremities [relative risk (RR)=2.27, 95%confidence interval (Cl)=1.44–3.59), back pain (RR=1.84;Cl=1.237–2.75), vasospastic disease of the fingers (RR=2.05;Cl=1.18–3.57) and obstructive respiratory symptoms (attacksof dyspnea and wheezing: RR=3.67; Cl=1.167–11.6).     

Excès de cas humains et animaux de tularémie en France au cours de l’hiver 2007–2008 : émergence ou phénomène isolé ?

Context

Tularemia is a zoonosis affecting humans and hares in France. We describe the results of surveillance in both species, in 2007 and 2008.

Methods

Human tularemia cases are mandatorily notifiable in France since 2003. In hares, surveillance relies on volunteer hunter associations in all districts of the country. Data from mandatory reports and volunteer surveillance in 2007/2008 were analyzed and compared with previous results.

Results

In 2007/2008, 144 cases were reported in humans and 117 cases in hares. This was a 100% increase compared to previous years. Human cases differed from those of previous years only by the frequency of contact with breeding animals. Human cases without any documented risk exposure were also more frequent.

Conclusion

An increase of tularemia cases occurred in 2007/2008 in both species. Complementary studies are needed to identify the species reservoir in France to understand the causes of this peak of cases.     

Occupational health hazards in mining: an overview

This review article outlines the physical, chemical, biological, ergonomic and psychosocial occupational health hazards of mining and associated metallurgical processes. Mining remains an important industrial sector in many parts of the world and although substantial progress has been made in the control of occupational health hazards, there remains room for further risk reduction. This applies particularly to traumatic injury hazards, ergonomic hazards and noise. Vigilance is also required to ensure exposures to coal dust and crystalline silica remain effectively controlled.     

Manufacture and use of nanomaterials: current status in the UK and global trends

This paper provides an overview of the production and use of nanomaterials (NMs), particularly in the UK. Currently, relatively few companies in the UK are identifiable as NM manufacturers, the main emphasis being the bulk markets in metals and metal oxides, and some niche markets such as carbon nanotubes and quantum dots. NM manufacturing in the UK does not reflect the global emphasis on fullerenes, nanotubes and fibres. Some assumptions have been made about the types of NM that are likely to be imported into the UK, which currently include fullerenes, modified fullerenes and other carbon-based NMs including nanotubes. Many university departments, spin-offs and private companies have developed processes for the manufacture of NMs but may only be producing small quantities for research and development (R&D) purposes. However, some have the potential to scale up to produce large quantities. The nanotechnology industry in the UK has strong R&D backup from universities and related institutions. This review has covered R&D trends at such institutions, and appropriate information has been added to a searchable database. While several companies are including NMs in their products, only a few (e.g. manufacturers of paints, coatings, cosmetics, catalysts, polymer composites) are using nanoparticles (NPs) in any significant quantities. However, this situation is likely to change rapidly. There is a need to collect more information about exposure to NPs in both manufacturing and user scenarios. As the market grows, and as manufacturers switch from the micro- to the nanoscale, the potential for exposure will increase. More research is required to quantify any risks to workers and consumers.     

深圳公立医院管理体制改革制度设计

深圳公立医院管理体制改革实行政事分开、管办分开,在理事会架构下按法定机构模式组建市医管中心,落实公立医院运营管理自主权.作者从当前公立医院管理体制的弊端入手,介绍了深圳市进行公立医院管理体制改革的基本思路及改革方案设计的主要举措,深入剖析了的改革方案的特点,并对改革效果进行了预测.     

Effects of nitrogen dioxide on red blood cells of rats: Changes in components of red cell membranes during in vivo exposure to NO2

Red cell membranes, prepared from red blood cells of rats exposed to 4, 10, or 20 ppm nitrogen dioxide (NO₂) for 1 to 10 days, were examined for evidence of changes in membrane components. Appreciable changes were not found in contents of phospholipid and cholesterol during exposure to 10 ppm NO₂. By contrast, protein content altered with the time of exposure. Moreover, changes in protein composition were observed by employing sodium dodecyl sulfate — polyacrylamide gel electrophoresis. Twenty-four-hour exposure to NO₂ at the concentration above 10 ppm resulted in a marked increase in the percentage of lysophosphatidylethanolamine (LysoPE) to the total phospholipids. The prolonged exposure to 10 ppm NO₂ gave rise to a further increase in LysoPE, whereas the percentage of phosphatidylethanolamine (PE) showed a gradual decrease. A 1-day exposure to 4.0 ppm NO₂ also caused an increase in sialic acid content and decreases in those of PE and hexose. In addition to contents of these components the percentage of LysoPE increased 5 days after exposure and the elevated values were maintained up to the end of exposure period. These results demonstrate that red blood cells in circulation exhibit different membrane properties in terms of lipid and carbohydrate composition during 10 days of exposure to 4.0 ppm NO₂.     

Investigating clusters in the workplace and beyond

Clusters of disease are common and occur in the workplace and in the general community. They often arouse considerable concern among the population. Investigations have sometimes lead to exciting new knowledge, but in general the investigation of clusters is difficult and often unrewarding, especially for community clusters. In the workplace, investigations are more likely to find associations and even new causes, but still many clusters remain enigmatic. Despite this, there are many reasons for investigating clusters, including allaying community concern and identifying uncontrolled exposures. A structure for investigating clusters in the workplace is suggested.