莱菔硫烷对汞致大鼠肾急性损伤的保护作用

目的 探讨莱菔硫烷(sulforaphane,SFN)对莱菔硫烷(sulforaphane,SFN)所致大鼠急性肾损伤的保护作用。 方法 清洁级Wistar大鼠30只按体重随机分5组,每组6只,分别为对照组,低、中、高剂量染汞组, SFN干预组。对照组及各染汞组皮下注射生理盐水,SFN干预组皮下注射2 mg/kg SFN;2 h后,对照组腹腔注射生理盐水,其他四组腹腔注射2.2、4.4、8.8、8.8 μmol/kg HgCl₂,连续3 d,染毒容量均为5 ml/kg。于最后一次染毒结束后,测定尿液中Hg及尿蛋白含量,碱性磷酸酶(ALP)、乳酸脱氢酶(LDH)和β-N-乙酰氨基葡萄糖苷酶(NAG)活力;腹主动脉采血测定血清尿素氮(BUN)含量;测定肾皮质中Hg含量和谷胱甘肽(GSH)、丙二醛(MDA)水平及超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活力。分析各组各项指标差异。 结果 与对照组比较,各剂量染汞组大鼠尿Hg、肾皮质Hg含量,尿蛋白和血清BUN 含量,尿NAG、LDH 和ALP 活力,肾皮质中GSH 和MDA含量显著升高(P<0.05或P<0.01);肾皮质SOD 和GSH-Px 活力显著降低(P<0.05或P<0.01)。与8.8 μmol/kg HgCl₂组比较,SFN 干预组尿蛋白和血清BUN 含量、尿NAG、LDH 和ALP活力、肾皮质GSH 、MDA含量均显著下降(P<0.05或P<0.01);肾皮质SOD 和GSH-Px 活力显著升高(P<0.01),而尿汞、肾皮质汞含量间差异无统计学意义(P>0.05)。 结论 莱菔硫烷对汞所致大鼠急性肾毒性有一定的保护作用。     

茶多酚对氯化汞染毒大鼠急性肾损伤的影响

目的探讨茶多酚(tea polyphenols,TP)对氯化汞染毒大鼠急性肾损伤的影响。方法将30只成年清洁级Wistar大鼠按体重随机分为5组,分别为对照(豆油)组,2.2、4.4、8.8μmol/kg氯化汞单独染毒组和TP(500 mg/kg)+氯化汞(8.8μmol/kg)染毒组,每组6只,雌雄各半。对照组和各氯化汞单独染毒组空腹以豆油灌胃,TP+氯化汞染毒组空腹灌胃500mg/kg TP溶液,灌胃容量为5 ml/kg,2 h后,TP+氯化汞染毒组和各氯化汞单独染毒组皮下注射染毒氯化汞,对照组注射生理盐水,染毒容量为5 ml/kg;每天染毒1次,连续染毒2 d。染毒结束后,检测尿汞、肾皮质汞含量,尿β-N-乙酰氨基葡萄糖苷酶(NAG)、尿乳酸脱氢酶(LDH)、尿碱性磷酸酶(ALP)活力,尿蛋白、血尿素氮(BUN)含量,肾皮质还原型谷胱甘肽(GSH)、丙二醛(MDA)含量,超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)活力。结果随着氯化汞染毒剂量的升高,大鼠尿汞、肾皮质汞含量,尿NAG、LDH、ALP活力,尿蛋白、血BUN含量,肾皮质GSH、MDA含量均呈上升趋势,肾皮质SOD和GSH-Px活力均呈下降趋势。与8.8μmol/kg氯化汞单独染毒组比较,TP+氯化汞染毒组大鼠尿NAG、LDH、ALP活力,尿蛋白、血BUN含量,肾皮质GSH、MDA含量均下降,肾皮质GSH、MDA含量和SOD、GSH-Px活力均上升,差异有统计学意义(P0.01);而尿汞、肾皮质汞含量间差异无统计学意义。结论 TP预处理对汞致大鼠急性肾损伤有一定的拮抗作用。     

五味子乙素对汞性大鼠急性肾损伤的影响

目的探讨五味子乙素(Sch B)对汞致大鼠急性肾损伤的影响。方法 Wistar大鼠30只,按体重随机分成5组:第1组为正常对照组,第2~4组分别为低、中、高剂量单纯染汞组,第5组为Sch B预处理组。对照组和单纯染汞组空腹以大豆油灌胃,Sch B预处理组16 mg/kg Sch B空腹灌胃,灌胃容量为5 ml/kg;2 h后,对照组皮下注射生理盐水,低、中、高剂量单纯染汞组分别皮下注射2.2μmol/kg、4.4μmol/kg、8.8μmol/kg氯化汞,Sch B预处理组皮下注射8.8μmol/kg氯化汞,注射容量为5 ml/kg。第二日重复上述操作,并将大鼠放入代谢笼,收集24 h尿液;而后将大鼠乙醚麻醉,腹主动脉采血,切取大鼠肾皮质,测定尿汞和肾皮质汞,尿β-N-乙酰氨基葡萄糖苷酶(NAG)、尿乳酸脱氢酶(LDH)及尿碱性磷酸酶(ALP)活力,尿蛋白和血尿素氮(BUN)含量,肾皮质还原型谷胱甘肽(GSH)和丙二醛(MDA)含量,超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)活力。结果与对照组比较,高剂量氯化汞组尿汞和肾皮质汞含量,尿NAG、LDH及ALP活力,尿蛋白和BUN含量,GSH和M...     

镉致大鼠肾脏毒性机制研究

目的研究镉对肾脏产生的毒性作用,并初步探讨镉的肾脏毒性机制。方法低、中、高剂量染镉组大鼠分别皮下注射3,5,7μmol CdCl2/（kg·bw）6周。测定尿镉、蛋白含量和尿N-乙酰-β-D氨基葡萄糖苷酶（NAG）、碱性磷酸酶（ALP）、乳酸脱氢酶（LDH）活性,测定肝脏和肾皮质丙二醛（MDA）和谷胱甘肽（GSH）含量。结果尿蛋白含量和尿NAG、ALP、LDH活性以及肝、肾皮质MDA和GSH含量随染镉剂量增加而升高。中剂量染镉组尿蛋白含量和尿NAG、LDH活性以及肾皮质MDA、GSH含量显著高于对照组和低剂量染镉组。高剂量染镉组尿蛋白含量、ALP活性、肝和肾皮质MDA显著高于对照组和低中剂量染镉组。且尿镉、蛋白含量、尿NAG、ALP、LDH活性与肾皮质MDA含量呈显著正相关。结论镉生物学效应随染毒剂量增加而增强,CdCl2 5μmol/（kg·bw）对肾脏产生一定损伤作用,CdCl2 7μmol/（kg·bw）时肾脏损伤加重。镉的肾毒性机制与其氧化损伤作用有关。     

氯丙嗪和异搏定对镉毒性的拮抗作用

目的 探讨氯丙嗪（Chlorpromazine，CPZ）和异搏定（Verapamil，Ver）对镉毒性的影响。方法 32只Wis—tar大鼠随机分成4组：对照组、单纯染镉组、氯丙嗪及异搏定干预组。测定肝和肾皮质镉、丙二醛（MDA）、谷胱甘肽（GSH）含量和谷胱甘肽过氧化物酶（GSH-Px）、超氧化物歧化酶（SOD）活性以及尿N-乙酰-β-D氨基葡萄糖苷酶（NAG）和碱性磷酸酶（ALP）活性。结果 单纯染镉组肝、肾皮质MDA、GSH含量和尿NAG和ALP活性显著高于对照组，而。肾皮质SOD活性显著低于对照组。CPZ干预组肝和。肾皮质MDA含量分别为单纯染镉组的75％，78％；肾皮质GSH含量显著低于单纯染镉组，而GSH-Px和SOD活性显著高于对照组和单纯染镉组。Ver干预组肝、肾皮质MDA和肾皮质GSH含量显著低于单纯染镉组，而肾皮质GSH-Px活性显著高于对照组，肾皮质SOD活性显著高于单纯染镉组。2个干预组尿NAG活性显著低于单纯染镉组。结论 CPZ和Ver对镉毒性具有一定的拮抗作用。     

番茄红素对氯化汞致大鼠肾损伤保护作用

目的 探讨番茄红素对氯化汞中毒致大鼠肾损伤的保护作用.方法大鼠以番茄红素灌胃2h后皮下注射氯化汞,每日1次,连续2d.测定肾皮质中汞、还原型谷胱甘肽(GSH)、丙二醛(MDA)、超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px);血清尿素氮(BUN);尿中蛋白、汞、碱性磷酸酶(ALP)、β-N-乙酰氨基葡萄糖苷酶(NAG)和乳酸脱氢酶(LDH)含量.结果 番茄红素处理组尿LDH、ALP、NAG活力分别为(113.19±23.74),(73.64±21.51),(103.73±21.79) U/g Cr,尿蛋白为(4.40±1.12)g/g Cr,与高剂量染汞组比较,明显升高;番茄红素组大鼠肾皮质中GSH、MDA为(45.33±5.90),(1.03±0.12) μmol/g pro,SOD和GSH-Px活力为(39.94±6.04),(85.62±12.68) U/mg pro,血清BUN含量为(15.93±9.36) mmol/L,与染汞组比较,差异均具有统计学意义(P＜0.05).结论番茄红素对大鼠氯化汞所致的肾损伤具有一定保护作用.     

α-硫辛酸和牛磺酸对亚慢性镉染毒致肾损伤影响的实验研究

目的通过观察α-硫辛酸(LA)和牛磺酸(Tau)对亚慢性镉染毒致肾损伤的影响,探讨氧化损伤在镉中毒中的作用。方法实验用大鼠32只,分为4组。给3个实验组大鼠皮下注射7μmol/kg的氯化镉(CdCl2)溶液,每周5次,连续6周。对照组大鼠在相应时间皮下注射生理盐水。于第7周、第8周,两干预组大鼠分别腹腔注射35μmol/kg的LA溶液和0.8 mmol/kg的Tau溶液,对照组和单纯镉染毒组在相应时间内腹腔注射生理盐水。注射容量均为5 ml/kg,每周5次。最后1次注射后,收集大鼠12 h尿液,然后处死大鼠,切取肝、肾组织。测定尿N-乙酰-β-D氨基葡萄糖苷酶(NAG)、碱性磷酸酶(ALP)活力及尿肌酐、尿蛋白和尿镉含量,肝和肾皮质镉、丙二醛(MDA)、谷胱甘肽(GSH)含量及谷胱甘肽过氧化物酶(GSH-Px)和超氧化物歧化酶(SOD)活力。结果与对照组比较,单纯镉染毒组的肝、肾皮质和尿中镉含量显著增加,尿ALP和NAG酶活力及尿蛋白含量显著升高,肾皮质GSH和MDA含量升高到34.65μg/g蛋白和171.05 nmol/g蛋白,GSH-Px活力下降到0.23 U/mg蛋白,差异有显著性。肝GSH含量升高,SOD和GSH-Px活力均显著下降。与单纯镉染毒组比较,LA干预组的尿镉含量、尿ALP活力和尿蛋白含量显著下降,肾皮质GSH和MDA含量降低到19.72μg/g蛋白和127.47 nmol/g蛋白,GSH-Px活力升高到0.30 U/mg蛋白,肝GSH-Px和SOD活力显著升高;Tau干预组的肝膈和尿镉含量均显著降低。肾皮质GSH含量降低到26.36μg/g蛋白,GSH-Px活力升高到0.37 U/mg蛋白。结论氧化损伤是镉中毒机制的一部分,LA和Tau对镉致肾氧化损伤的恢复具有一定的促进作用。     

亚硒酸钠对急性和亚慢性镉毒性的拮抗作用

目的探讨急性、亚慢性镉染毒对大鼠的肝、肾毒性以及亚硒酸钠(Na2SeO3)对镉染毒大鼠肝、肾毒性的拮抗作用。方法急性实验时,Na2SeO3干预组大鼠以10μmol/kg腹腔注射Na2SeO3溶液,对照组和镉染毒组腹腔注射0.9%氯化钠。2 h后,干预组和镉染毒组大鼠皮下注射氯化镉(CdCl2)溶液35μmol/kg,对照组皮下注射0.9%氯化钠。亚慢性实验时,大鼠皮下注射CdCl2溶液7μmol/kg,每周5 d,1次/d,连续6周。然后Na2SeO3干预组大鼠腹腔注射Na2SeO3溶液10μmol/kg,共2周,对照组在相同时间注射0.9%氯化钠。测定大鼠血清、尿液和肝、肾组织中各酶的活力。结果急性镉染毒使大鼠血清乳酸脱氢酶(LDH)、丙氨酸转氨酶(ALT)活力明显升高,肝谷胱甘肽(GSH)、丙二醛(MDA)含量明显升高,谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)活力明显下降。Na2SeO3预处理可使急性镉染毒大鼠血清ALT、LDH活力分别降低至单纯镉染毒组的63.8%(166.61,261.11)和30.1%(40.85,135.52),差异有统计学意义(P<0.01),肝GSH、MDA含量明显降低,而GSH-Px、SOD活力明显升高。亚慢性镉染毒使大鼠尿碱性磷酸酶(ALP)、N-乙酰-β-苷酶(NAG)活力和尿蛋白含量明显升高,肾皮质GSH、MDA含量明显升高,GSH-Px活力明显降低。Na2SeO3处理使亚慢性镉染毒大鼠尿ALP酶活力明显下降,肾皮质GSH、MDA含量明显降低,GSH-Px活力明显升高。结论Na2SeO3对急性镉染毒所致肝损伤具有明显的保护作用,对亚慢性镉染毒致肾损伤的恢复具有一定的促进作用。     

硒对氯化汞致大鼠肾氧化损伤影响

目的 探讨氯化汞(HgCl2)诱导大鼠肾毒性作用并观察亚硒酸钠的拮抗效应.方法 Wistar大鼠24只随机分成3组,分别为阴性对照组(皮下注射质量分数为0.9%生理氯化钠溶液),染汞组(皮下注射HgCl22.5 mg/kg体质量),亚硒酸钠干预组(先腹腔注射亚硒酸钠20μmol/kg体质量,2 h后皮下注射HgCl2溶液2.5 mg/kg).注射后12 h将大鼠移入代谢笼,收集12 h尿样.注射后48 h处死,留取血样和肾组织.测定肾和尿汞水平及尿N-乙酰-β-D-氨基葡萄苷酶(NAG)、碱性磷酸酶(ALP)、乳酸脱氢酶(LDH)活力和尿蛋白、血清尿素氮(BUN)、肾谷胱甘肽(GSH)、丙二醛(MDA)、蛋白水平和超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活力.结果 与染汞组相比,亚硒酸钠干预组肾汞、尿汞水平下降(P<0.01),尿NAG、ALP、LDH活力下降(P<0.05或P<0.01),尿蛋白、BUN水平下降(P<0.01).肾GSH-Px活力升高(P<0.05),MDA水平降低(P<0.05).结论 HgCl2可诱导大鼠肾脏发生急性氧化性损伤,亚硒酸钠对该急性肾氧化损伤具有一定拮抗作用.     

姜黄素对染镉6周大鼠肾损伤的影响

[目的]探讨姜黄素(curcumin)对氯化镉染毒大鼠亚慢性肾损伤的影响,为镉中毒的发病机制和防治提供实验依据。[方法]将48只Wistar大鼠按体重随机分成4组,每组12只,第1组为对照组,第2组为低剂量染镉组,第3组为高剂量染镉组,第4组为姜黄素干预组。周一至周五每天进行染毒,第1组腹腔注射生理盐水,第2~4组分别腹腔注射3、6、6μmol/kg氯化镉溶液;每周一、三、五染毒前2 h进行干预,第1~3组皮下注射生理盐水,第4组皮下注射50 mg/kg姜黄素,注射容积均为5 m L/kg;连续处理6周,最后一次染毒结束后24 h,检测尿乳酸脱氢酶(LDH)、尿碱性磷酸酶(ALP)及尿N-乙酰-β-氨基葡萄糖苷酶(NAG)活性,尿蛋白含量,血清尿素氮(BUN)含量,肾皮质还原型谷胱甘肽(GSH)、丙二醛(MDA)含量和超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性,肾细胞内ROS水平及细胞凋亡率。[结果]与对照组比较,各染镉组大鼠的体重增长幅度均降低;高剂量染镉组大鼠尿蛋白、血清BUN含量,尿LDH、ALP、NAG活性,肾皮质MDA含量均增加[分别为(2.51±0.57)g/g肌酐、(32.82±4.99)mmol/L,(1 180.54±293.55)、(211.53±46.39)、(104.94±18.58)U/g肌酐,(4.59±0.67)μmol/g蛋白],肾皮质GSH含量,SOD、GSH-Px活性均下降[分别为(26.75±6.92)μmol/g蛋白,(35.65±6.27)、(62.91±20.50)U/mg蛋白],肾细胞内ROS的含量升高[(527.50±60.12)平均荧光强度],细胞凋亡率增大[(41.88±4.10)%];姜黄素干预组与高剂量染镉组比较,各项指标均得到不同程度的改善。[结论]给大鼠亚慢性染镉可对肾脏产生明显的氧化损伤作用;姜黄素处理对镉引起的肾损伤具有一定的拮抗作用。     

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.