hnRNP E1与HPV16早期基因E2和E6在宫颈癌变中的作用及交互效应

目的 探讨核不均一核糖核蛋白（hnRNP）E1与HPV16早期基因E2和E6在宫颈癌变进展中的作用及相互关系。方法 从在山西省介休市建立的自然人群宫颈病变队列中,选取2014年6-9月经病理学确诊的正常宫颈（NC）女性56例,低度宫颈上皮内瘤变（CIN Ⅰ）病例58例和高度宫颈上皮内瘤变（CIN Ⅱ/Ⅲ）病例50例,以及同期在山西省肿瘤医院确诊的40例宫颈鳞状细胞癌（SCC）病例作为研究对象。采用结构式问卷收集研究对象的宫颈病变相关资料的同时,采集宫颈组织活检标本和宫颈脱落细胞。采用导流杂交法检测HPV感染状况,采用Western Blot检测hnRNP E1以及HPV16 E2和E6蛋白表达水平。采用SPSS 22.0软件进行Kruskal-Wallis H检验、χ²检验、趋势χ²检验和logistic回归分析,采用广义多因子降维法（GMDR）评价交互作用。结果 HPV16感染率在CINⅠ（15.52%,9/58）、CINⅡ/Ⅲ（40.00%,20/50）和SCC组（67.50%,27/40）均高于NC组（8.93%,5/56）,并随着宫颈病变程度的加重呈现升高趋势（趋势检验χ²=43.613,P<0.001）。hnRNP E1表达量在不同宫颈病变组间差异有统计学意义（H=9.98,P=0.019）,且随宫颈病变程度的加重呈现降低趋势（趋势检验χ²=9.495,P=0.002）。HPV16 E2（H=16.20,P=0.001）和E6（H=15.44,P=0.001）表达水平在不同宫颈病变组间差异均有统计学意义。采用GMDR分析显示,hnRNP E1低表达、HPV16 E2低表达与HPV16 E6高表达在CIN Ⅱ/Ⅲ和SCC组中存在交互作用（P<0.05）,而在CIN Ⅰ组未发现存在交互效应（P>0.05）。结论 hnRNP E1低表达和HPV16早期基因的异常表达可能会增加宫颈病变的发病风险,并在宫颈癌变中存在交互作用。     

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。     

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。     

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。     

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。     

细胞外信号调节激酶1/2表达与HPV16感染及其交互效应在子宫颈癌变中的作用

目的 探讨细胞外信号调节激酶（p-ERK）1/2表达与HPV16感染在子宫颈癌变中的作用及其交互效应。方法 选取2013年9月至2014年3月在山西省肿瘤医院、山西省妇幼保健院、山西省晋煤集团总医院经组织病理学确诊的正常子宫颈（NC）女性34例、低度子宫颈上皮内瘤变（CINⅠ）患者26例、高度子宫颈上皮内瘤变（CINⅡ/Ⅲ）患者57例和子宫颈鳞状细胞癌（SCC）患者59例为研究对象。采用调查问卷收集研究对象的人口学特征和子宫颈癌相关因素等资料,并采集子宫颈组织标本。采用PCR法检测HPV16感染状况,应用免疫组化法检测子宫颈组织中磷酸化ERK1/2（p-ERK1/2）蛋白的表达情况。同时使用ERK抑制剂U0126对子宫颈癌细胞Siha（HPV16阳性）和C33A（HPV阴性）进行抑制,比较抑制前后细胞的增殖、凋亡情况。结果 随着子宫颈癌变的进展,HPV16感染率（趋势χ²=17.99,P<0.001）和p-ERK1/2的表达率（趋势χ²=10.58,P=0.001）均逐渐升高,HPV16感染与p-ERK1/2蛋白表达在CINⅠ、CINⅡ/Ⅲ、SCC组中均存在正相加交互作用。细胞实验结果显示,ERK抑制后,Siha和C33A细胞均表现为增殖能力降低（Siha：t=6.863,P<0.001;C33A：t=7.092,P<0.001）、凋亡率增高（Siha：t=-5.201,P=0.006;C33A：t=-4.335,P=0.005）。ERK抑制后HPV16阳性Siha细胞较HPV阴性C33A细胞增殖指数高（t=7.066,P<0.001）、凋亡率低（t=-2.431,P=0.057）。结论 p-ERK1/2高表达和HPV16感染均可增加子宫颈癌变风险,两者在子宫颈癌变中存在正相加交互作用。在子宫颈癌细胞增殖凋亡过程中,ERK1/2的活化可能对HPV16感染细胞的作用更为显著。     

FHIT基因甲基化及蛋白表达与HPV16感染在宫颈癌变中的交互效应

目的 探讨脆性组氨酸三联体(FHIT)基因甲基化及蛋白表达异常与HPV16感染在宫颈癌变中的作用及其交互效应。方法 选择2009年9月至2011年3月在山西省肿瘤医院、山西医科大学第二医院妇科、太原市妇幼保健院和介休市妇幼保健院就诊的宫颈鳞状细胞癌(SCC)新发患者100例,宫颈上皮内瘤样变(CIN)患者142例(72例CIN1,70例CIN2+)和正常宫颈(NC)妇女108例为研究对象。采用多重PCR法检测HPV16感染状况,应用甲基化特异性PCR(MSP)和Western Blot法分别检测FHIT基因甲基化状态和蛋白的表达水平。利用SPSS 20.0软件进行相关资料的t检验、方差分析、χ²检验、因素与疾病关联效应分析(OR值及其95%CI),应用相加效应模型进行交互作用评价。结果 HPV16感染率在CIN1组(45.8%)、CIN2+组(68.6%)和SCC组(73.0%)均高于NC组(28.7%),差异均有统计学意义(P<0.001);在NC、CIN1、CIN2+和SCC组,FHIT基因甲基化率分别为3.7%、13.9%、21.4%和38.0%,蛋白表达水平分别为1.255±0.130、1.184±0.172、1.133±0.126和1.099±0.148,各组的差异均有统计学意义(P<0.001);随宫颈病变程度的加重,HPV16感染率逐渐升高(趋势检验χ²=47.623,P<0.001),FHIT基因甲基化率逐渐升高(趋势检验χ²=40.147,P<0.001),FHIT蛋白低表达率也逐渐升高(趋势检验χ²=65.098,P<0.001);FHIT基因高甲基化、FHIT蛋白低表达与HPV16感染在不同宫颈病变组均存在正相加交互效应。结论 FHIT基因高甲基化和FHIT蛋白低表达与HPV16感染均可增加宫颈癌及其癌前病变的发生风险,FHIT基因高甲基化和FHIT蛋白低表达与HPV16感染在宫颈癌变中均具有协同作用。     

hnRNP E1与HPV16及其早期蛋白E2在宫颈上皮内瘤样变中的相互关系研究

目的 探讨hnRNP E1与HPV16及其早期蛋白E2在宫颈上皮内瘤样变（CIN）中的交互作用。方法 问卷收集研究对象CIN相关因素,采集宫颈组织和宫颈脱落细胞。分子导流杂交技术检测HPV16感染状况,western blot法检测hnRNP E1及HPV16 E2蛋白量。结果 HPV16阳性率随宫颈病变程度加重,呈现上升趋势（P＜0.001）,CINⅡ/Ⅲ组E2蛋白表达量低于CINⅠ和NC组（P＜0.05）,且随宫颈病变程度进展,其低表达率呈现升高的趋势。CINⅡ/Ⅲ组的hnRNP E1蛋白表达量低于NC组（P＜0.001）。hnRNP E1蛋白与HPV16 E2蛋白间存在正相关关系。hnRNP E1蛋白低表达与HPV16感染在CINⅡ/Ⅲ发生中呈正相加交互作用,但在CINⅠ组未发现类似交互作用。结论 hnRNP E1蛋白低表达与HPV16感染、HPV16 E2蛋白低表达均可增加CIN的患病风险,HPV16感染与hnRNP E1蛋白在高级别CIN患病中可能存在协同作用。     

叶酸与p16蛋白在宫颈癌变中的作用及其相互效应

目的 探讨叶酸与p16蛋白在宫颈癌变中的作用及其相互效应。方法 选取经病理学确诊的80例正常宫颈（NC）妇女、55例低度宫颈上皮内瘤样变（CINⅠ）患者、55例高度宫颈上皮内瘤样变（CINⅡ/Ⅲ）患者、64例宫颈鳞状细胞癌（SCC）患者为研究对象。分别采用微生物法和Western-blot方法检测其血清叶酸水平和p16蛋白的表达量。同时采用体外细胞实验研究方法,对HPV阴性的宫颈癌细胞C33A和HPV16阳性的宫颈癌细胞Caski进行不同浓度叶酸干预,检测两种宫颈癌细胞的增殖和凋亡情况,以及p16蛋白的表达。结果 NC组、CINⅠ组、CINⅡ/Ⅲ组和SCC组血清叶酸含量分别为（5.96±3.93） ng/ml、（5.08±3.43） ng/ml、（3.92±2.59） ng/ml、（3.18±2.71） ng/ml,p16蛋白表达水平分别为0.80±0.32、1.33±0.52、1.91±0.77、2.09±0.72;随着宫颈病变的进展,血清叶酸含量逐渐降低（趋势检验 χ²=32.71,P<0.001）,p16蛋白表达量逐渐升高（趋势检验 χ²=56.06,P<0.001）。在CINⅠ、CINⅡ/Ⅲ、SCC组中血清叶酸缺乏与p16蛋白高表达均存在正相加交互作用。体外实验结果显示,随着叶酸浓度的增加,宫颈癌细胞的增殖抑制率（C33A：r=0.928,P=0.003;Caski：r=0.962,P=0.001）和凋亡率（C33A：r=0.984,P<0.001;Caski：r=0.986,P<0.001）均上升,p16蛋白表达量逐渐降低（C33A：r=-0.817,P=0.025;Caski：r=-0.871,P=0.011）,且p16蛋白表达量与宫颈癌细胞的增殖抑制率（C33A：r=-0.935,P=0.002;Caski：r=-0.963,P=0.001）和凋亡率（C33A：r=-0.844,P=0.017;Caski：r=-0.898,P=0.006）均呈负相关关系。结论 血清叶酸缺乏与p16蛋白高表达均可增加宫颈癌和癌前病变的发病风险,两者在宫颈癌和癌前病变中存在正相加交互作用。补充叶酸可逆转p16蛋白的异常表达,有效抑制宫颈癌细胞的增殖,促进凋亡。     

高危型HPV E6/E7 mRNA与宫颈癌相关性分析

目的 探讨高危型HPV E6/E7 mRNA检出率与宫颈癌的相关性,为临床防治宫颈癌提供依据。方法 选择2015年收治的100例宫颈癌患者为A组,同期100例健康体检者为B组,采用荧光定量PCR检测入组患者高危型HPV E6/E7 mRNA和病理学检查,比较两组患者HPV E6/E7感染率和荧光定量PCR检查效率,分析HPV E6/E7感染与宫颈鳞状上皮病变的相关性。结果 A组阳性76例,阳性率为76.0%;B组阳性13例,阳性率为13.0%;A组阳性率高于B组,差异有统计学意义（χ²=24.522,P<0.001）。两组阳性预测值和阴性预测值比较,差异无统计学意义（P>0.05）。宫颈癌患者HPV E6/E7 mRNA阳性率（76.0%）高于高度宫颈鳞状上皮病变者（26.1%）、低度宫颈鳞状上皮病变者（17.6%）和非典型鳞状上皮细胞者（6.7%）,差异有统计学意义（χ²=7.615,P=0.001; χ²=9.114,P=0.001; χ²=18.241,P<0.001）。结论 宫颈癌患者HPV E6/E7mRNA检出率高,且随宫颈鳞状上皮病变加重,其HPV E6/E7 mRNA阳性率越高。     

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.     

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.     

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.     

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.     

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.