高危型人乳头瘤病毒感染的转归特点及阴道微环境因子对其转归影响的研究

目的 探讨高危型人乳头瘤病毒（HR-HPV）感染的转归特点及阴道微环境因子对其转归的影响。方法 从本课题组前期建立的社区队列中,选取HR-HPV感染、经病理学诊断为正常宫颈的421名女性为研究对象,进行24个月的随访。在收集基线资料的基础上,应用需氧菌性阴道炎/细菌性阴道病联合检测试剂盒测定阴道微环境因子,采用导流杂交技术检测HPV感染状况。根据基线和随访24个月后HR-HPV的感染状况,描述HR-HPV感染的转归特征,并探讨阴道微环境因子对HR-HPV感染转归的影响。结果 在390名完成24个月随访的HR-HPV感染女性中,HR-HPV持续感染率居前5位的型别依次为HPV16（24.1%）、HPV58（22.2%）、HPV53（21.7%）、HPV52（20.0%）和HPV39（11.8%）。阴道pH值（aOR=1.74,95%CI：1.08~2.80）、唾液酸苷酶（aOR=2.70,95%CI：1.52~4.83）和白细胞酯酶（aOR=3.41,95%CI：2.13~5.44）异常可增加HR-HPV持续感染的风险,其中唾液酸苷酶和白细胞酯酶异常均可增加同型和异型HR-HPV持续感染的风险。结论 HPV16容易发生持续感染,阴道pH值、唾液酸苷酶和白细胞酯酶异常可增加HR-HPV持续感染的风险,特别是唾液酸苷酶、白细胞酯酶异常作用更为明显。     

阴道微环境改变与HPV16感染在宫颈上皮内瘤变中的作用及其交互效应

目的 探讨阴道微环境改变和HPV16感染在宫颈上皮内瘤变中的作用及其交互效应。方法 研究对象来源于课题组前期在山西省建立的宫颈病变研究队列,包括623例正常宫颈（NC）妇女、303例低度宫颈上皮内瘤变（CINⅠ）患者和93例高度宫颈上皮内瘤变（CINⅡ/Ⅲ）患者。在收集其人口学特征和宫颈上皮内瘤变相关因素资料的同时,采用导流杂交技术检测HPV16感染状况,应用需氧菌性阴道炎/细菌性阴道病联合检测试剂盒检测阴道分泌物中的H₂O₂、β-葡萄糖醛酸苷酶、凝固酶、唾液酸酐酶和白细胞酯酶,以及阴道pH值和清洁度。应用SPSS 22.0软件进行数据的录入和资料分析。结果 随着宫颈病变的进展,HPV16感染率（趋势性χ²=55.45,P<0.001）、H₂O₂ （趋势性χ²=26.19,P<0.001）、pH值（趋势性χ²=5.06,P=0.024）、阴道清洁度（趋势性χ²=19.55,P<0.001）、β-葡萄糖醛酸苷酶（趋势性χ²=17.52,P<0.001）、唾液酸酐酶（趋势性χ²=14.90,P<0.001）的异常率均逐渐升高,而凝固酶和白细胞酯酶异常率未见相应趋势。广义多因子降维模型交互作用分析显示,在CINⅠ组,HPV16感染与H₂O₂、β-葡萄糖醛酸苷酶、凝固酶、唾液酸酐酶异常呈交互作用,在CINⅡ/Ⅲ组,HPV16感染与阴道清洁度、H₂O₂、β-葡萄糖醛酸苷酶、唾液酸酐酶异常呈交互作用。结论 阴道微环境改变和HPV16感染均可增加宫颈病变的发病风险,且在宫颈上皮内瘤变中具有交互作用。     

人乳头瘤病毒感染和阴道微环境紊乱与宫颈病变的关系

目的 探讨人乳头瘤病毒（HPV）感染和阴道微环境紊乱与宫颈病变的关系及其交互效应。方法 从课题组前期建立的自然人群队列中选取基线调查时确定的正常宫颈（NC）妇女623人、低度宫颈病变（CIN Ⅰ）妇女303人及高度宫颈病变（CIN Ⅱ/Ⅲ）妇女93人为研究对象。以NC为对照组、CIN为病例组，采用病例对照研究方法，在收集研究对象人口学特征、生殖情况、生活习惯、既往病史宫颈病变相关因素的基础上，应用导流杂交法检测HPV分型，需氧菌性阴道炎/细菌性阴道炎联合检测试剂盒检测阴道分泌物中的H₂O₂，精密pH试纸检测阴道pH值，涂片法检测阴道清洁度。利用SPSS 20.0软件进行相关资料的分析。结果 HPV（CINⅠ：aOR=1.39，95% CI：1.01~1.90；CIN Ⅱ/Ⅲ：aOR=11.74，95% CI：6.96~19.80）、H₂O₂（CINⅠ：aOR=2.09，95% CI：1.47~2.98；CIN Ⅱ/Ⅲ：aOR=4.12，95% CI：2.01~8.43）、清洁度（CIN Ⅱ/Ⅲ：aOR=2.62，95% CI：1.65~4.14）和综合指标（CIN Ⅰ：aOR=1.67，95% CI：1.24~2.25；CIN Ⅱ/Ⅲ：aOR=4.24，95% CI：2.30~7.81）均可增加宫颈病变的患病风险，随着宫颈病变的进展，HPV（趋势性χ²=81.33，P<0.001）感染率、阴道pH值（趋势性χ²=5.06，P=0.024）、H₂O₂（趋势性χ²=26.19，P<0.001）、清洁度（趋势性χ²=19.55，P<0.001）和综合指标（趋势性χ²=30.50，P<0.001）的异常率均呈逐渐升高趋势。交互作用分析显示，HPV感染与阴道微环境的综合指标在CIN Ⅱ/Ⅲ组中显示有正相加交互作用，而无论HPV感染与否，阴道微环境紊乱致CIN Ⅰ的OR值比较接近。结论 HPV感染和阴道微环境紊乱均可增加宫颈病变的患病风险，尤其在CIN Ⅱ/Ⅲ发生发展中两者可能存在协同作用，而在CIN Ⅰ发生中阴道微环境紊乱的作用不可忽视。     

p16/mcm2双染在宫颈上皮内瘤变的诊断价值及其与高危型HPV感染的关系

目的 研究p16/mcm2免疫细胞化学双染在宫颈病变中的表达及其与HPV感染的关联,并探讨其在宫颈癌筛查中的应用价值。方法 将2015年5-12月参加宫颈癌筛查并行高危型HPV（HR-HPV）检测和液基细胞学检查的1 127名女性纳入研究,对留存细胞学标本进行p16/mcm2免疫细胞化学双染检测,并与宫颈组织病理学结果进行比较。结果 p16/mcm2在HPV16/18阳性组和其他HR-HPV阳性组的表达风险均高于HPV阴性组,OR值分别为15.95（95%CI：9.59~26.51）、10.53（95%CI：7.41~14.98）;p16/mcm2阳性率随宫颈上皮内瘤变（CIN）级别的升高而升高,且在CIN2组、CIN3组中均高于良性病变组（P<0.05）;p16/mcm2阳性者中检出CIN2及以上（CIN2+）和CIN3及以上（CIN3+）病变的灵敏度分别为86.1%、92.0%,特异度分别为46.1%、44.4%;在细胞学诊断为非典型鳞状细胞和低度鳞状上皮内病变人群中检出CIN2+和CIN3+病变的灵敏度分别为85.7%、87.5%,特异度分别为45.5%、44.1%。结论 p16/mcm2双染灵敏度高于细胞学检查,特异度优于HPV检测,可识别宫颈高度病变和指导CIN的分级,有望成为新的宫颈癌筛查标志物。     

多环芳烃与高危型人乳头瘤病毒感染在宫颈上皮内瘤变中的作用及其交互效应

目的 探讨多环芳烃（PAHs）与高危型人乳头瘤病毒（HR-HPV）感染在宫颈上皮内瘤变发生发展过程中的作用及其交互效应。方法 从建立的自然人群队列中选取2014年6－12月经病理学确诊的正常宫颈（NC）妇女208例,低度宫颈上皮内瘤变（CIN Ⅰ）患者154例,高度宫颈上皮内瘤变（CIN Ⅱ/Ⅲ）患者124例为研究对象。采用高效液相色谱法检测其尿中1-羟基芘（1-OHP）的浓度（反映PAHs内暴露情况）,应用导流杂交技术检测HPV感染状态及感染类型。利用SPSS 22.0软件进行资料的χ²检验、χ²趋势检验、Kruskal-Wallis H检验、Nemenyi秩和检验、Spearman秩相关分析,采用相加模型评价两因素间交互作用。结果 NC、CIN Ⅰ、CIN Ⅱ/Ⅲ组HR-HPV感染率分别为27.9%、37.0%、58.9%,尿1-OHP浓度（μmol/molCr）分别为0.07±0.09、0.11±0.10、0.17±0.15。随着宫颈病变程度的加重,HR-HPV感染率（趋势检验χ²=29.89,P<0.001）和PAHs高暴露率（趋势检验χ²=27.94,P<0.001）均逐渐升高。HR-HPV感染与尿中1-OHP浓度呈正相关（r=0.680,P<0.001）。CIN Ⅱ/Ⅲ组中HR-HPV感染与PAHs高暴露存在正相加交互作用,而在CIN Ⅰ组中未发现存在类似交互作用。结论 HR-HPV感染和PAHs高暴露均可增加宫颈上皮内瘤变的患病风险,两者在高度宫颈上皮内瘤变发生发展中存在协同作用。     

膳食水溶性维生素对低度宫颈上皮内瘤变转归影响的前瞻性队列研究

目的 探讨膳食水溶性维生素对低度宫颈上皮内瘤变（CINⅠ）转归的影响。方法 采用以社区为基础的前瞻性队列研究方法,从课题组于2014年建立的已婚女性队列中,选择经病理学确诊的564名CINⅠ患者为研究对象,在收集一般基线资料的同时,应用导流杂交技术检测HPV分型,采用食物频数问卷调查膳食水溶性维生素的摄入情况,确定暴露水平,进而对研究对象进行12个月的随访观察。随访结束时再次取活检组织行病理学检查,判定CINⅠ患者的逆转、持续和进展情况。采用SPSS 22.0软件进行相关资料的分析。结果 膳食水溶性维生素低水平可促进CINⅠ患者的持续或进展,且CINⅠ不良转归的风险随维生素摄入水平的降低而升高,尤其是叶酸、维生素B1、维生素B2、维生素B6、烟酸、生物素和维生素C（RR值分别为15.22、1.86、1.92、2.11、2.98、2.14和2.19）低水平对CINⅠ的持续/进展起到重要促进作用。结合HR-HPV感染状况进行分析后显示,HR-HPV阳性时,叶酸、烟酸和生物素低水平可促进CINⅠ持续和进展。结论 膳食水溶性维生素低水平是CINⅠ持续和进展的重要促进因素,对于HR-HPV阳性女性,叶酸、烟酸和生物素的作用更为明显。     

hnRNP K在宫颈上皮内瘤样变中的作用及其与HPV16交互效应

目的 探讨hnRNP K与HPV16感染在宫颈上皮内瘤样变（CIN）中的作用及其交互效应。方法 选取2014年6月至2015年6月在山西省介休市建立的社区队列中经病理学确诊的正常宫颈（NC）女性67例和CIN患者137例（CINⅠ患者69例、CINⅡ/Ⅲ患者68例）为研究对象。采用结构式问卷收集研究对象人口学资料及宫颈病变相关因素的基础上，采集宫颈脱落细胞和宫颈活检或手术组织，应用分子导流杂交法检测HPV16感染状况，并采用Western blot技术检测宫颈组织中hnRNP K蛋白表达水平。采用SPSS 23.0软件对资料进行整理分析，研究对象的人口学特征、相关因素、hnRNP K蛋白和HPV16感染在NC组、CINⅠ和CINⅡ/Ⅲ组的差异通过χ²检验、趋势χ²检验、Kruskal-Wallis H检验进行比较；hnRNP K蛋白表达量的组间两两多重比较采用Bonferroni法；采用非条件logistic回归模型计算hnRNP K蛋白、HPV16感染与CIN的关联强度OR值及其95% CI，采用相加交互模型及交互效应指标评价hnRNP K蛋白和HPV16感染两因素在CIN中的交互效应。结果 CINⅡ/Ⅲ组HPV16感染率（41.2%）高于NC（10.4%）、CINⅠ（14.5%），差异有统计学意义（P<0.001），且随着CIN程度加重，HPV16的感染率呈上升趋势（趋势χ²=18.512）。hnRNP K蛋白表达量在NC组、CINⅠ组和CINⅡ/Ⅲ组间差异有统计学意义（H=48.138，P<0.001），且随着CIN程度加重呈上升趋势（趋势χ²=21.765，P<0.001）。交互效应分析显示，hnRNP K蛋白高表达与HPV16感染在CINⅡ/Ⅲ组存在正相加交互作用（API=0.639，95% CI：0.083~1.196），在CINⅠ组尚未发现存在类似交互作用。结论 hnRNP K蛋白高表达、HPV16感染均可能增加CIN的发生风险，且在高度CIN发生中存在正相加交互作用。     

HPV16长控制区甲基化与宫颈上皮内瘤变2级及以上病变关系的Meta分析

目的 系统评价和分析人乳头瘤病毒16型（HPV16）长控制区（LCR）甲基化与宫颈上皮内瘤变2级及以上病变（CIN2+）之间的相关性。方法 计算机系统检索PubMed、Embase、Cochrane Library、Web of Science、中国知网、万方数据知识服务平台、维普数据库等,检索国内外公开发表的中英文文献,按纳入排除标准筛选文献,检索年限为建库至2022年2月27日。采用RevMan 5.3和Stata 15.1软件进行统计学分析。结果 最终纳入17篇文献,研究对象共1 421例。Meta分析结果显示,HPV16 LCR甲基化与CIN2+关系的合并效应OR值为1.56（95%CI：0.70~3.47）。亚组分析结果显示,5''端、增强子区和启动子区甲基化与CIN2+均未显示相关性;4个E2结合位点（E2BS）中,E2BS1、E2BS3和E2BS4甲基化增加CIN2+的发生风险,OR值分别为3.92（95%CI：1.92~7.99）、10.50（95%CI：3.67~30.04）和3.65（95%CI：1.58~8.41）,由于文献篇数限制,未对E2BS2进行亚组分析;在不同地区人群来源中,中国人群CIN2+的发生风险与HPV16 LCR甲基化具有相关性,OR值为2.14（95%CI：1.31~3.50）;对HPV16 LCR进行焦磷酸测序的人群CIN2+的发生风险与HPV16 LCR甲基化具有相关性,OR值为1.75（95%CI：1.03~2.98）。结论 CIN2+的发生风险与HPV16 LCR E2BS的甲基化存在相关性。     

多环芳烃与p16、FHIT基因CpG岛甲基化在宫颈上皮内瘤变中的交互效应

目的 探讨多环芳烃与p16、FHIT基因CpG岛甲基化在宫颈上皮内瘤变（CIN）中的作用及其交互效应。方法 利用2014年6-12月建立的山西省阳曲县宫颈病变研究队列。包括经病理学确诊的CIN患者169例（CINⅠ86例,CINⅡ/Ⅲ 83例）和正常宫颈（NC）妇女91例。全部研究对象采用高效液相色谱法检测尿液中的1-羟基芘（1-OHP）浓度,甲基化特异性PCR法检测抑癌基因p16、FHIT CpG岛甲基化状态。应用SPSS 20.0软件进行相关资料的Kruskal-Wallis H检验、χ²检验、趋势χ²检验,应用logistic回归模型计算因素与宫颈疾病之间关联强度的OR值及其95%CI,应用广义多因子降维模型（GMDR）评价交互作用。结果 随着CIN程度加重,1-OHP水平逐渐上升（H=50.743,P<0.001）,1-OHP高暴露率逐渐升高（趋势检验χ²=20.146,P<0.001）。CINⅠ、CINⅡ/Ⅲ组p16、FHIT CpG岛甲基化率均高于NC组;随着CIN程度的加重,p16基因CpG岛甲基化率（趋势检验χ²=9.75,P=0.002）、FHIT基因CpG岛甲基化率（趋势检验χ²=10.39,P=0.001）均逐渐升高。GMDR交互作用分析显示,在CINⅠ和CINⅡ/Ⅲ组,1-OHP高暴露与p16、FHIT基因CpG岛甲基化呈交互作用。结论 1-OHP高暴露和p16、FHIT CpG岛甲基化均可增加CIN的风险,且在病变中具有协同作用。     

红细胞叶酸对高危型人乳头瘤病毒感染转归影响的前瞻性队列研究

目的 探讨红细胞叶酸对高危型人乳头瘤病毒（HR-HPV）感染转归的影响。方法 从课题组于2014年在山西省建立的已婚女性自然人群队列中,选择经病理学确诊的低度宫颈上皮内瘤变（CINⅠ）患者564名为研究对象。采用前瞻性队列研究的方法,在基线收集研究对象一般人口学特征、HPV感染相关因素的同时,利用化学发光免疫分析法进行红细胞叶酸水平的测定,依此将研究对象分为不同水平暴露组并在第24个月对其进行随访。应用导流杂交技术对研究对象基线及随访结束时的宫颈脱落细胞进行HPV感染状况检测,依据其变化情况判定HR-HPV持续感染、由阳转阴、由阴转阳和持续阴性4种不同结局,探讨红细胞叶酸对HR-HPV感染转归的影响。采用SPSS 22.0软件进行资料分析。结果 483名女性完成了24个月的随访观察,随访率为85.64%（483/564）,HR-HPV持续感染率为52.45%（75/143）,由阳转阴率为47.55%（68/143）,由阴转阳率为19.71%（67/340）,持续阴性率为80.29%（273/340）。红细胞叶酸低水平组发生持续感染（aRR=2.50,95%CI：1.55~4.02）及由阴转阳（aRR=4.55,95%CI：2.52~8.23）的风险高于高水平组,特别是同型持续感染的发生风险（aRR=2.72,95%CI：1.51~4.90）较高。随着红细胞叶酸水平的降低,HR-HPV持续感染（趋势检验χ²=20.62,P<0.001）、由阴转阳（趋势检验χ²=31.76,P<0.001）和同型持续感染（趋势检验χ²=20.09,P<0.001）的发生风险呈升高趋势,在异型持续感染中未见类似结果。结论 红细胞叶酸低水平可增加HR-HPV持续感染和由阴转阳的风险,特别是HR-HPV感染女性,发生同型持续感染的危险性更大。     

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.