儿童血瘦素水平对青春期发育的作用

目的研究血瘦素水平对儿童青春期发育的作用.方法单纯性肥胖和健康学生各300名,调查男生首次遗精和女生月经初潮时间,测定血瘦素、性激素、生长激素和胰岛素水平.结果随年龄增长,瘦素在男生呈低→高→低变化,肥胖组(1.04±0.21)nmol/L→(1.20±0.27)nmol/L→(0.66±0.10)nmol/L,对照组(0.31±0.06)nmol/L→(0.45±0.10)nmol/L→(0.19±0.04)nmol/L;在女生呈增高趋势,肥胖组从(0.89±0.15)nmol/L增至(1.39±0.23)nmol/L,对照组从(0.46±0.08)nmol/L增至(0.88±0.18)nmol/L.各组性激素呈增高趋势.生长激素呈某一年龄突增,且男女不同(男生14～15岁,女生13～14岁).各年龄肥胖组瘦素和胰岛素高于对照组;男生各年龄肥胖组生长激素低于对照组.男女肥胖组血瘦素水平高于对照组,男(0.71±0.17)nmol/L与(0.30±0.04)nmol/L,女(1.11±0.21)nmol/L与(0.70±0.18)nmol/L;其初潮/首次遗精时间提前,男(12.5±1.2)岁与(13.2±1.2)岁,女(11.6±0.8)岁与(12.8±0.9)岁.女生瘦素水平高于男生,其初潮时间早于男生首次遗精时间.肥胖组男生的睾酮与瘦素呈负相关,女生的雌二醇与瘦素呈正相关,男生的生长激素与瘦素呈负相关,女生的生长激素与瘦素呈正相关;对照组女生的胰岛素与瘦素呈正相关.结论瘦素对青春期的启动可能有重要作用,对女性可能比男性更为重要;瘦素与生长激素相关关系的两性差异可能是造成男女生长突增时间不同的原因之一;瘦素与性激素相关关系的两性差异可能是造成男女首次遗精/初潮时间不同的原因之一.     

腰背痛病人血清肌酸激酶和乳酸脱氢酶及其同功酶的水平

目的　探讨腰背痛病人血清肌酸激酶 (creatinekinase ,CK)、肌型肌酸激酶 (CK MM )、乳酸脱氢酶 (lactatedehydrogenase,LDH)及其同功酶的水平。 方法　应用病例 -对照研究 ,选择腰背痛病人 6 8例 ,对照人员 70例 ,取静脉血 ,应用琼脂糖凝胶电泳法、聚丙烯酰胺凝胶电泳法和酶动力学法测定两组人群血清中总CK及其肌型同功酶、总LDH及其同功酶的活力。结果　病例组血清CK总活力〔(15 5 93± 5 3 6 1)IU/L〕高于对照组〔(131 4 2± 5 1 79)IU/L〕 ,差异有显著性 (P <0 0 1) ;病例组血清CK MM同功酶中CK MM1活力〔(4 5 4 3± 6 2 2 )IU/L〕低于对照组〔(5 5 95± 8 84 )IU/L〕 ,差异有显著性 (P <0 0 5 ) ,CK MM2 活力〔(32 34± 5 19)IU/L〕与对照组〔(30 90± 5 30 )IU/L〕比较 ,差异无显著性 ,CK MM3 活力〔(2 2 2 4±4 77)IU/L〕高于对照组〔(13 0 5± 3 0 1)IU/L〕 ,差异有显著性 (P <0 0 1) ;病例组CK MM3 /CK -MM1比值(0 5 1± 0 13)高于对照组 (0 2 3± 0 0 7) ,差异有显著性 (P <0 0 1)。病例组血清肌型同功酶LDH5虽高于对照组 ,但与对照组比较 ,差异无显著性。结论　腰背痛病人血清CK、LDH及其同功酶发生变化 ,说明腰背痛病人肌肉有损伤 ,CK是其血清中变化较敏感的指标     

二甲双胍与妈富隆联合治疗多囊卵巢综合征

目的　观察二甲双胍与去氧孕烯炔雌醇片 (商品名 :妈富隆 )联合应用 ,对多囊卵巢综合征患者内分泌及代谢的影响。方法　以 6 0例多囊卵巢综合征不孕患者为观察组 ,进行前瞻性研究 ;30例非多囊卵巢综合征不孕妇女为对照组。测定体块指数、腰臀围比值、多毛评分及生殖内分泌激素、糖、脂代谢指标等。观察组根据随机应用不同药物以分为去氧孕烯炔雌醇片组、二甲双胍组及二甲双胍与去氧孕烯炔雌醇片联合用药组 (联合用药组 ) ,每组各 2 0例。经 12周治疗后 ,比较上述各项指标的变化。结果　观察组治疗前体块指数、腰臀围比值、多毛评分、黄体生成激素、睾酮、空腹胰岛素、胰岛素抵抗及甘油三酯等均较对照组增高 ;高密度脂蛋白、胆固醇较对照组降低 (P <0 .0 1)。各观察组治疗前各项指标差异均无显著性 (P >0 .0 5 )。治疗 12周后 ,联合用药组及二甲双胍组黄体生成激素分别从 (13.0± 4 .9)IU L降低为 (5 .1± 1.2 )IU L ,从 (12 .8± 5 .6 )IU L降低为 (10 .9± 5 .8)IU L ;三组的睾酮分别从 (1.9± 0 .6 )nmol L降低为 (1.1± 0 .6 )nmol L ,从(2 .0± 0 .9)nmol L降低为 (1.3± 0 .4 )nmol L ,从 (2 .3± 2 .1)nmol L降低为 (1.5± 0 .8)nmol L ;游离睾酮分别从 (2 .7± 2 .1)nmol L降低为 (0 .9± 0 .5 )     

L-甲状腺素和干甲状腺片在甲减替代治疗中的疗效比较

目的　比较L -甲状腺素 (Levo -thyroxine ,LT4 )和干甲状腺片 (Tab .Thyroid)在甲状腺功能减退症 (甲减 )替代治疗中的疗效 ,探讨LT4 在甲减替代治疗中的价值。方法　 1 0 6例甲减患者被随机分成两组 ,干甲状腺片组 55例 (Tab .Thyroid 2 0～ 1 60mg/d) ,LT4 组 51例 (LT4 2 5～ 2 0 0 μg/d) ,随访治疗 1年。TSH正常以前每 1～ 4周随诊 1次血清TSH、FT3和FT4 。TSH正常以后每 4～ 1 2周随诊 1次。结果　从治疗开始至血清TSH转为正常所需时间分别为 (9.3± 6 .7)周 (干甲状腺片组 )和 (8.2± 5 .1 )周 (LT4 组 ) (P >0 .0 1 )。血清TSH正常后干甲状腺片组血清FT3高于LT4 组 [(5 .81± 1 .86)pmol/L ,(4.58± 1 .97) pmol/L ,P <0 .0 0 0 5] ,血清FT4 低于LT4 组 [(1 2 .2 9±5 .0 3) pmol/L ,(2 2 .35± 7.86)pmol/L ,P <0 .0 0 0 5]。LT4 治疗过程中 1 4例呈高FT4 血症 ,2例呈高FT3血症 ,仅有 2例发生一过性头痛 ,余未见明显副作用 ;而干甲状腺片组只 1例高FT4 血症 (P <0 .0 0 5) ,1 0例高FT3血症 (P<0 .0 2 5)。结论　两药疗效大致相同 ,但LT4 效价稳定 ,高T3血症少见     

2型糖尿病患者瘦素水平及其相关因素分析

目的　研究 2型糖尿病患者血清瘦素与性别、体重指数 (BMI)、腰臀比 (WHR)、胰岛素、血糖、总胆固醇和甘油三脂的关系。方法　随机选取 5 6例 2型糖尿病患者与 2 2例非糖尿病者 ,分别测定入选对象的体重指数、腰臀比值 (WHR)、空腹瘦素、空腹和餐后 2h血糖、总胆固醇和甘油三脂。结果　血清平均瘦素水平男性 ( 8 5± 0 9)ug/L ,女性 ( 17 2± 1 1)ug/L ,女性明显高于男性 ,血清瘦素与BMI呈显著正相关 (γ =0 64 ,P <0 0 1) ,与男性WHR显著正相关 (γ =0 5 0 ,P <0 0 1) ,血清瘦素与胰岛素显著正相关(空腹γ =0 3 6,P <0 0 1,餐后 2hγ =0 3 4,P <0 0 1) ,瘦素与血糖、血脂没有相关性。结论　血清瘦素浓度与BMI、男性WHR显著正相关 ,与胰岛素有显著正相关性。     

某些常见神经系统疾病血清和脑脊液中TNF-α和IL-10含量变化及其临床意义

目的　探讨促炎性细胞因子与抑炎细胞因子在某些常见神经系统疾病的分布规律。方法　ELISA法测定 6种神经系统疾病病人血清和脑脊液 (CSF)白介素 1 0 (IL - 1 0 )和肿瘤坏死因子α(TNF -α)水平 ,并进行相关比较研究。结果　 (1 )CSF中IL - 1 0水平 :多发性硬化 (MS)组 (330 .5± 2 51 .8)ng/L、癫痫组 (61 .2± 48.6)ng/L、脑炎组(44.6± 2 1 .7)ng/L、蛛网膜下腔出血组 (SAH) (2 3 .4± 1 9.8)ng/L ,显著高于对照组 (5 .6± 1 .32 )ng/L(P值均 <0 .0 5) ;(2 )CSF中TNF -α水平 :脑炎组 (43 .8± 2 3 .2 )ng/L、SAH组 (41 .0± 1 7.9)ng/L、脊髓病组 (2 7.8± 7.5)ng/L、癫痫组 (76 .1± 2 7.5)ng/L ,明显高于对照组 (1 8.6± 5 .0 )ng/L(P值均 <0 .0 5) ;(3)血清中IL - 1 0水平 ,MS组(97.8± 60 .0 )ng/L、癫痫组 (60 .1± 40 .4)ng/L、SAH(37.9± 2 2 .3)ng/L ,显著高于对照组 (1 0 .4± 3 .5)ng/L(P值均 <0 .0 5) ;(4)血清中TNF -α水平 :SAH组 (1 72 .4± 93 .7)ng/L、MS组 (1 1 0 .3± 86 .1 )ng/L、癫痫组 (1 0 0 .9±86 .1 )ng/L、脑炎组 (32 .1± 1 7.2 )ng/L ,明显高于对照组 (1 9.8± 4 .4)ng/L(P值均 <0 .0 5)。结论　 (1 )脑炎、SAH、脊髓病、癫痫等病人CSF和血清中伴随促炎性和抑炎性反应     

新生儿脐血瘦素水平及其相关因素的探讨

【目的】　探讨脐血瘦素水平与胎儿宫内生长发育相关性。　【方法】　采用放免检测新生儿脐血瘦素水平 ,采用Ponderal指数〔PI=10 0×体重 (g) /身长 (cm) 3 〕估测新生儿营养状态 ,采用weststrate公式〔F % =0 .8848×SFT4+0 .0 2 2〕估测新生儿体脂含量。　【结果】　 3 7例适于胎龄儿 (AGA)脐血瘦素水平为 ( 10 .5 7± 3 .0 3 ) μg/L ,不同性别AGA脐血瘦素水平无显著差异 (P >0 .0 5 )。 13例大于胎龄儿 (LGA)脐血瘦素水平为 ( 13 .15± 3 .5 1) μg/L ,显著高于AGA(P =0 .0 14 ) ;15例小于胎龄儿 (SGA)脐血瘦素水平为 ( 8.0 5± 2 .69) μg/L ,显著低于AGA(P =0 .0 0 72 )。脐血瘦素水平与新生儿出生体重 (BW )相关系数r=0 .65 (P <0 .0 1) ,与新生儿体脂含量 (F % )相关系数r =0 .2 8(P <0 .0 5 ) ,与新生儿Ponderal指数 (PI)相关系数r =0 .62 (P <0 .0 1)。　【结论】　脐血瘦素水平是胎儿宫内生长发育状态的敏感指标 ,脐血瘦素可能是胎儿宫内生长发育的调节因子。     

软骨藻酸对H4细胞血红素氧化酶-1的诱导

[目的 ]研究软骨藻酸对H4细胞血红素氧化酶 1(hemeoxygenase 1,HO 1)的诱导。 [方法 ]流式细胞仪检测0、0 .0 64、0 .64、6.4μmol/L软骨藻酸作用细胞 2 4h后HO 1蛋白表达、HO 1mRNA转录和HO 1酶活性。[结果 ]HO 1蛋白表达 :0 .0 64、0 .64、6.4μmol/L浓度组的荧光强度分别为 ( 68.0 7± 7.0 7)、( 81.3 4± 8.64 )和 ( 81.95± 8.3 0 ) ,与对照组 ( 60 .60± 5 .3 6)比较 ,差异均有显著性 (P <0 .0 1)。HO 1mRNA转录 :0 .0 64 μmol/L组相对表达量为 ( 0 .43 9± 0 .0 0 7) ,与对照组( 0 .411± 0 .0 0 8)比较差异无显著性 (P >0 .0 5 ) ;0 .64 μmol/L和 6.4μmol/L组分别为 ( 0 .5 0 6± 0 .0 13 )和 ( 0 .63 1± 0 .0 3 6) ,与对照组比较差异有显著性 (P <0 .0 1)。HO 1酶活性 :0 .0 64mol/L组为 ( 3 89.3 2± 3 4.75 )pmol/(mg·h) ,与对照组 ( 3 2 6.75±2 7.0 5 )pmol/(mg·h)相比 ,差异无显著性 (P >0 .0 5 ) ;0 .64和 6.4μmol/L组分别为 ( 4 61.75± 2 7.84)和 ( 687.5 0± 3 5 .93 )pmol/(mg·h) ,与对照组相比 ,差异有显著性 (P <0 .0 1)。前述 3指标结果均有随剂量浓度增加而逐渐升高的趋势。 [结论 ]软骨藻酸能诱导H4细胞HO 1蛋白表达、HO 1mRNA转录和HO 1酶活性升高     

急性氨中毒患者心肌损伤的检测

目的　探讨检测急性氨中毒患者心肌损伤的比较好的指标。方法　分别测定 5 1例急性氨中毒患者及 2 0例正常对照组的心肌肌钙蛋白T(cTnT)、肌酸磷酸激酶 (CK)及其同工酶 (CK MB) ,同时作心电图检查。结果　重度氨中毒组心肌cTnT(1.2 85± 2 .6 5 0 ) μg L、CK(2 5 7.6 36± 36 2 .719)IU L、CK MB (2 0 .90 9± 19.770 )IU L ,均高于正常对照组 [心肌cTnT(0 .0 35± 0 .0 14 ) μg L、CK(82 .0 5 0± 36 .30 2 )IU L、CK MB(8.35 0± 2 .4 5 5 )IU L],差异有显著性 (P <0 .0 5 ) ;而轻度氨中毒组 [cTnT(0 .0 39± 0 .0 16 )μg L、CK(78.2 0 0± 2 8.4 0 1)IU L、CK MB(8.4 6 7± 2 .6 6 9)IU L]和中度氨中毒组 [cTnT(0 .0 5 4± 0 .0 4 3)μg L、CK(99.786± 71.94 1)IU L、CK MB(9.4 2 9± 3.85 7)IU L]与正常对照组相应各指标比较 ,差异无显著性 (P >0 .0 5 )。心肌cTnT的阳性检出率 [6 8.2 % (15 2 2 ) ]高于CK[36 .4 % (8 2 2 ) ]、CK MB[31.2 %(7 2 2 ) ]和心电图 [31.2 % (7 2 2 ) ],差异有显著性 (P <0 .0 5 )。结论　心肌cTnT有助于更好地检测重度氨中毒引起的心肌损伤。     

胎儿宫内窘迫孕妇血清瘦素水平的检测及临床意义

目的 :检测晚期妊娠妇女和胎儿宫内窘迫孕妇产前及产后血清瘦素水平的变化 ,以探讨瘦素与胎儿宫内窘迫的关系。方法 :采用放射免疫分析法 (RIA)测定 35例胎儿宫内窘迫孕妇和 40例正常晚期妊娠妇女产前及产后1 w血清瘦素水平及 30例正常健康孕妇瘦素水平。结果 :胎儿宫内窘迫孕妇产前瘦素水平为 (36.58± 9.1 0 ) μg/ L,明显高于正常晚期妊娠妇女产前瘦素水平 (2 1 .30± 5.1 8)μg/ L ,两者比较 ,有显著性差异 (P<0 .0 1 )。胎儿宫内窘迫孕妇产后瘦素水平为 (8.61± 4.44)μg/ L,与正常晚期妊娠妇女产后瘦素水平 (7.56± 2 .76)μg/ L比较 ,无显著性差异(P>0 .0 5) ,两组分别与正常健康未孕妇女血清瘦素水平 (7.44± 2 .48) μg/ L比较 ,也均无显著差异 (P均 >0 .0 5)。结论 :晚期妊娠妇女瘦素水平的异常升高与胎儿宫内窘迫有关 ,且主要与胎盘来源的瘦素有关。推测对孕妇瘦素水平进行动态监测可作为预示发生胎儿宫内窘迫的一项临床指标     

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.