瓷厂和钨矿生产性粉尘生物学效应的研究

目的 通过体外细胞实验测定瓷厂和钨矿作业点生产性粉尘的毒性等生物学效应,为评价粉尘的危害作用提供依据.方法 以豚鼠的肺泡巨噬细胞(AM)为作用细胞,以标准石英作为对照,应用肺泡灌洗的方法获得AM后,加入15、30、60、120μg/106个细胞浓度标准石英、瓷厂及钨矿作业点的呼吸性粉尘颗粒培养,测定细胞的乳酸脱氢酶(LDH)活力、细胞活力(MTT)、活性氧释放量和肿瘤坏死因子-α(TNF-α)的释放量.结果 瓷厂和钨矿的生产性粉尘均能诱导豚鼠AM培养液中LDH活力升高,诱导豚鼠AM释放活性氧和TNF-α量升高,并随粉尘浓度升高呈现明显的剂量一反应关系.瓷厂和钨矿粉尘与豚鼠AM共培养后导致AM活力下降,随着生产性粉尘的浓度增加而降低.钨矿粉尘引起LDH活力升高以及诱导豚鼠AM释放TNF-α能力强于瓷厂粉尘,在120μg/106个细胞浓度组,赣州钨矿粉尘诱导的TNF-α水平为(5.2±2.0)ng/ml,景德镇瓷厂粉尘诱导的TNF-α水平为(3.3±1.6)ng/ml,均高于标准石英(2.8±0.5)ng/ml.与钨矿尘肺患病和死亡率均高于瓷厂相印证.结论 不同来源的生产性粉尘具有不同的生物学效应结果,实验测定粉尘的生物学效应为区分生产性粉尘危害作用提供了基础数据.     

纳米颗粒致人血管内皮细胞损伤的比较

目的 比较3种不同类型的颗粒对血管内皮细胞的毒性效应,探讨颗粒成分和粒径对其心血管的毒性效应.方法 选择纳米二氧化硅(nano-SiO2)、纳米二氧化钛(nano-TiO2)和标准石英作为染尘颗粒,其中nano-TiO2和标准石英分别作为nano-SiO2的成分对照和粒径对照.将剂量为5.0、10.0、20.0、40.0 μg/ml的3种颗粒分别作用于人脐静脉内皮细胞,以不含颗粒物的DMEM培养液为对照组,24 h后收集培养液上清,测定乳酸脱氢酶(LDH)、总超氧化物歧化酶(SOD)活力、NO、肿瘤坏死因子-α(TNF-α)和白细胞介素-6(IL-6)释放量.结果 与0μg/ml剂量组比较,各剂量nano-SiO2染尘组和10.0、20.0、40.0 μg/ml nano-TiO2染尘组及标准石英染尘组的LDH活力明显升高,差异均有统计学意义(P＜0.01).与0 μg/ml剂量组比较,5.0、10.0、20.0 μg/ml nano-SiO2染尘组和40.0 μg/ml nano-TiO2染尘组及20.0、40.0 μg/ml标准石英染尘组的SOD活力明显增加,40.0μml nano-SiO2染尘组的SOD活力明显降低,差异均有统计学意义(P＜0.05,P＜0.01).与0μg/ml剂量组比较,10.0、20.0、40.0 μg/mlnano-SiO2染尘组和各剂量nano-TiO2染尘组及40.0 μg/ml标准石英染尘组的TNF-α释放量明显增加,差异均有统计学意义(P＜0.01).与0μg/ml剂量组比较,10.0、20.0、40.0 μg/mlnano-SiO2染尘组和20.0、40.0μg/ml nano-TiO2染尘组及40.0 μg/ml标准石英染尘组的IL-6释放量明显增加,差异有统计学意义(P＜0.01).5.0、10.0、20.0、40.0 μg/ml nano-SiO2染尘组的LDH活力明显高于标准石英染尘组,10.0、20.0、40.0 μg/ml nano-TiO2染尘组LDH活力明显低于标准石英染尘组,差异均有统计学意义(P＜0.05).5.0、10.0、20.0μg/ml nano-SiO2染尘组SOD活力明显高于标准石英染尘组,40.0 μg/ml nano-SiO2染尘组和20.0 μg/ml nano-TiO2染尘组SOD活力明显低于标准石英染尘组,差异均有统计学意义(P＜0.01).5.0、10.0、20.0、40.0 μg/ml nano-SiO2染尘组和5.0、10.0μg/ml nano-TiO2染尘组的TNF-α释放量均明显高于标准石英染尘组,差异均有统计学意义(P＜0.01).5.0、10.0、20.0、40.0μg/ml nano-SiO2染尘组和20.0、40.0 μg/ml nano-TiO2染尘组的IL-6释放量明显高于标准石英染尘组,差异有统计学意义(P＜0.05).结论 3种颗粒都能够对细胞产生一定的毒性效应,其中以nano-SiO2的作用最强,nano-TiO2和标准石英的细胞毒性表现不一.颗粒物毒性与其成分和粒径有关.     

不同地区大气PM2.5对大鼠肺泡巨噬细胞毒性作用的实验研究

目的比较不同地区大气PM2.5对肺泡巨噬细胞的毒性作用。方法采集广州市、东莞市、深圳市和肇庆市4个地区的大气PM2.5,将PM2.5分别以1、10、50、100、200、300μg/ml剂量对肺泡巨噬细胞染毒24 h。检测一氧化氮(NO)释放量、超氧化物歧化酶(SOD)活力、丙二醛(MDA)生成量、肿瘤坏死因子(TNF-α)水平、乳酸脱氢酶(LDH)漏出率及细胞存活率。以肇庆作为对照,观察PM2.5对各指标的影响。经剂量与效应指标回归分析,以斜率评价各地区PM2.5的效应大小。结果不同地区大气PM2.5致肺泡巨噬细胞释放TNF-α、NO、MDA的水平和LDH的漏出率均随着染毒剂量增加而升高,SOD的活力和细胞的存活率随染毒剂量升高而降低。深圳和东莞大气PM2.5对肺泡巨噬细胞胞内的SOD活力的抑制程度高于广州和肇庆(P<0.05)。深圳和东莞大气PM2.5致肺泡巨噬细胞内MDA的生成量明显高于肇庆(P<0.05)。广州大气PM2.5致肺泡巨噬细胞生成TNF-α量最高,其次为东莞,均明显高于肇庆(P<0.05)。广州大气PM2.5致肺泡巨噬细胞内LDH的漏出率最高,其次为东莞和深圳,均高于肇庆(P<0.05)。剂量高于100μg/ml时,广州、深圳和东莞大气PM2.5致肺泡巨噬细胞存活率低于肇庆(P<0.05)。回归分析显示,广州大气PM2.5对肺泡巨噬细胞的TNF-α、LDH漏出率、NO释放量的效应最强,肇庆大气PM2.5对肺泡巨噬细胞的LDH漏出率、NO释放量和细胞存活率的效应最低。结论不同地区大气PM2.5对大鼠肺泡巨噬细胞的毒性作用随染毒剂量增加而增强,广州、东莞、深圳地区大气PM2.5的毒性效应总体上强于肇庆地区。     

银杏叶提取物对肿瘤坏死因子α诱导的人脐静脉内皮细胞损伤的影响

目的研究银杏叶提取物肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)诱导的人脐静脉内皮细胞(human umbilical vein endothelial cell,HUVEC)损伤的保护作用。方法 TNF-α诱导HUVEC复制细胞损伤模型;分为正常组、TNF-α模型组、银杏叶提取物低剂量组(50μg/ml),银杏叶提取物高剂量组(100μg/ml),通过MTT法检测对HUVEC增殖的影响,流式细胞术检测银杏叶提取物对细胞周期的影响,硝酸还原酶法检测NO含量的变化,ELISA方法检测IL-6、IL-8、ET-1表达的变化,计量资料采用t检验,P0.05为差异有统计学意义。结果银杏叶提取物可以显著促进TNF-α诱导的HUVEC的增殖,银杏叶提取物高剂量组、低剂量组增殖率与模型组相比差异均有统计学意义(均P0.05)。银杏叶提取物可提高S期的细胞比例,可增加NO含量,抑制IL-6、IL-8、ET-1的表达,与模型组相比差异均有统计学意义(均P0.05)。结论银杏叶提取物具有保护血管内皮炎症损伤的作用。     

不同地区大气PM2.5对人血管内皮细胞毒性作用的实验研究

目的比较不同地区大气PM2.5对血管内皮细胞的毒性,并探讨其作用机制。方法采集广州、东莞、深圳和肇庆4个城市的PM2.5。试验细胞为人脐静脉内皮细胞。将PM2.5分别以10、50、100、200、300μg/ml剂量染毒,作用于细胞24 h,测定细胞NO释放量、SOD活力、LDH漏出量及细胞存活率(MTT试验)。以肇庆作为对照,观察PM2.5对各指标的影响。经剂量与指标回归分析,以斜率评价不同城市PM2.5的效应大小。结果各城市PM2.5致细胞NO释放量和LDH漏出量随剂量增加而升高,SOD活力和细胞存活率随剂量升高而降低(P<0.05)。广州和深圳PM2.5在高剂量时致NO释放量明显高于肇庆(P<0.05)。广州、东莞和深圳PM2.5致SOD活力降低的程度在各剂量组均强于肇庆(P<0.05)。深圳PM2.5致LDH释放量明显高于肇庆,广州、东莞在高剂量时高于肇庆(P<0.05)。广州、深圳PM2.5致细胞死亡率高于肇庆(P<0.05)。回归分析表明,广州PM2.5致LDH漏出和细胞死亡的毒性效应最高,深圳PM2.5对NO释放和SOD活力降低的毒性效应最高,肇庆PM2.5对NO、SOD、LDH的细胞毒性均处于最低水平。NO释放量、LDH漏出量与细胞存活率呈负相关,SOD活力与细胞存活率呈正相关(P<0.01)。结论不同城市PM2.5对血管内皮细胞的毒性表现不同。NO、SOD、LDH与细胞存活率有关联,氧化应激损伤可能是其作用机制之一。     

外向钾通道在纳米SiO2致内皮细胞毒性中的作用

目的探讨电压依赖性外向钾通道(voltage-dependent potassium channel,Kv)在纳米二氧化硅(SiO2)致血管内皮细胞毒性中的作用,以验证钾外流与纳米SiO2致细胞炎性反应的关系。方法以人脐静脉内皮细胞(HUVECs)正常培养为阴性对照组,单独加入20μg/ml纳米SiO2为阳性对照组,在20μg/ml纳米SiO2基础上添加不同剂量的Kv通道阻断剂氯化四乙胺(TEA-Cl)或4-氨基吡啶(4-AP)为实验组,检测各组细胞存活率、乳酸脱氢酶(LDH)活力、肿瘤坏死因子(TNF-α)以及白介素-6(IL-6)释放量。用全细胞膜片钳电生理测定正常HUVECs及染不同浓度纳米SiO2时Kv电流变化,验证纳米SiO2对血管内皮细胞Kv的影响。结果与阴性对照(正常细胞组)比较,纳米SiO2(阳性对照组)导致内皮细胞存活率明显降低,LDH活力、TNF-α和IL-6释放量明显增加。与阳性对照组比较,加入钾通道阻断剂TEA-Cl或4-AP后,细胞存活率明显升高,但高剂量阻断剂组反而降低。钾通道阻断剂也导致LDH活力降低,但在最高剂量时甚至达到阳性对照水平。只有高剂量TEA-Cl使TNF-α释放量明显减少,而4-AP自低到高剂量使TNF-α释放量逐渐降低,呈剂量-效应关系。TEA-Cl和4-AP均可明显降低纳米SiO2诱导IL-6释放量。膜片钳电生理实验中,内皮细胞Kv电流表现延迟整流特性,4-AP对该电流的抑制作用明显。与阴性对照(正常细胞组)比较,纳米SiO2导致外向钾电流明显增大,激活曲线左移,斜率因子降低(P<0.05),表明Kv活性增加,通道开放速率明显增高。结论纳米SiO2可引起细胞炎性反应,Kv开放引起的钾外流增加在该毒性效应中可能起着活化细胞、激活炎性体的早期信号作用。     

竹荪醇提物对脂多糖诱导的RAW264.7细胞炎症反应的影响

目的探讨竹荪醇提物对LPS诱导的RAW264.7细胞肿瘤坏死因子(TNF-α)、一氧化氮(NO)的分泌,TNF-α、诱导型一氧化氮合酶(iNOS)、白细胞介素6(IL-6)、白细胞介素10(IL-10)的m RNA水平以及核转录因子(NF-κB)p65蛋白表达的影响及可能的抗炎机制。方法以不同浓度(100、200、400μg/ml)的竹荪醇提物作用于LPS(1μg/ml)诱导的RAW264.7小鼠巨噬细胞,采用ELISA法和Griess法检测炎性介质TNF-α和NO的分泌量;RT-PCR法测定促炎介质TNF-α、iNOS、IL-6和抗炎介质IL-10的m RNA水平;Western blot检测NF-κB p65蛋白的表达水平。结果与LPS组相比,200、400μg/ml的竹荪醇提物能显著抑制LPS诱导的RAW264.7细胞TNF-α和NO的释放(P0.01);且不同程度抑制RAW264.7细胞中促炎介质iNOS、TNF-α和IL-6的m RNA表达水平(P0.01),剂量依赖性的促进抗炎介质IL-10的m RNA表达水平(P0.01);不同浓度的竹荪醇提物均可显著抑制LPS诱导RAW264.7细胞中NF-κB p65蛋白的表达,差异有统计学意义(P0.01)。结论竹荪醇提物可抑制LPS诱导的RAW264.7细胞TNF-α和NO的释放,其抗炎作用的发挥可能与抑制NF-κB p65蛋白的表达,从而调节炎性介质的基因水平有关。     

结缔组织生长因子对石英粉尘诱导人支气管上皮细胞释放IL-17A的影响

目的探讨结缔组织生长因子(CTGF)对石英粉尘诱导人支气管上皮细胞(16HBE)表达白介素17A(IL-17A)水平的影响。方法采用0、12.5、25、50、100μg/ml石英粉尘染毒人支气管上皮细胞(16HBE)24、48 h,采用CCK-8法测定细胞存活率,以荧光定量PCR方法检测细胞内CTGF mRNA相对表达水平;用CTGF siRNA干扰16HBE细胞12 h后,加入0、25、50μg/ml石英粉尘染毒48 h,并设同样剂量石英粉尘染毒的16HBE细胞为对照组,收集细胞上清液,采用酶联免疫吸附法(ELISA)检测细胞上清液中IL-17A的含量。结果与24 h染尘组比较,石英粉尘染毒16HBE细胞48 h后细胞毒性作用更明显,其细胞存活率随石英粉尘浓度的增加逐渐降低(P0.05);同时细胞内CTGF mRNA相对表达水平和细胞分泌IL-17A的水平均显著升高(P0.05),且呈剂量-效应关系,50μg/ml染毒组细胞内表达CTGF mRNA和分泌IL-17A的水平达到最高;与同样剂量石英粉尘染毒的16HBE细胞相比,25、50μg/ml石英粉尘诱导CTGF siRNA干扰组细胞分泌IL-17A的水平显著降低,差异具有统计学意义(P0.05)。结论抑制CTGF可显著降低石英粉尘诱导16HBE细胞表达IL-17A的水平,提示CTGF可能参与调节石英粉尘致肺部炎性及纤维化的反应过程。     

锡矿粉尘生物学活性与致病能力的关系

目的 通过体外细胞实验评价锡矿含石英粉尘的生物特性和毒性,并与接尘工人尘肺和肺癌等疾病发生进行比较.方法 选择鼠肺巨噬细胞为靶细胞,分别测定4个锡矿的呼吸性粉尘样本作用于靶细胞后,葡萄糖苷酸酶、乳酸脱氢酶、过氧化氢以及活性氧自由基（ROS）和肿瘤坏死因子-α（TNF-α）的释放.以标准石英（DQ12）和氧化铝作为对照.矿工人群流行病学研究为回顾前瞻性队列研究.结果 流行病学研究显示,锡矿接尘工人的尘肺标化死亡比（SMR）高达49.7（95%CI：39.5～61.8）,肿瘤（SMR=1.58,95%CI：1.39～1.76）和肺癌死亡率（SMR=3.17,95%CI：2.59～3.76）高于全国平均水平.锡矿粉尘的细胞毒性与细胞功能损伤作用高于氧化铝而低于石英,其诱导的ROS水平明显高于氧化铝和石英,此外,粉尘样本还导致TNF-α分泌升高,超过或接近纯石英粉尘的作用.结论 现场粉尘体外细胞实验结果能较好地解释人群流行病学调查的趋势,粉尘的体外毒性测定可能具有筛检现场粉尘危害的作用.     

纳米SiO_2致内皮细胞毒性作用剂量效应和时间效应

目的观察纳米二氧化硅颗粒(纳米SiO_2)对人脐静脉内皮细胞的毒性作用及其剂量和时间效应。方法将不同质量浓度(0、5、10、20、40mg/L)纳米SiO_2颗粒作用于人脐静脉内皮细胞,在不同时间点(6、12、24、48h)检测细胞培养液上清中乳酸脱氢酶(LDH)活性、总超氧化物歧化酶(SOD)活力、肿瘤坏死因子-α(TNF-α)和白介素-6(IL-6)的释放量。结果细胞培养液上清中LDH活性、TNF-α释放量和IL-6释放量呈浓度和时间依赖性增加。染尘6、12h,SOD活力随染尘浓度的增加而增加,染尘24h则先增后减,染尘48h则随染尘浓度的增加而减少;随着作用时间的延长,所有染尘浓度组SOD活力先增后减。结论纳米SiO_2颗粒能够诱导HUVECs发生膜损伤、氧化损伤和炎症反应,且存在剂量和时间效应。     

瓷厂与锡矿及钨矿石英粉尘表面铝硅酸盐包裹的测定和分析

目的 探讨石英粉尘表面铝硅酸盐包裹的测定方法和包裹对粉尘致病作用的影响.方法 应用呼吸性粉尘采样器以2 L/min采集江西钨矿、瓷厂和广西锡矿粉尘,用扫描电镜-能散X线分光计（SEM-EDS）以5 keV和20 keV电压照射测定呼吸性粉尘颗粒中各元素成分的含量,计算不同电子伏特照射下粉尘颗粒中硅与铝的比值.结果 7个瓷厂、3个锡矿和3个钨矿的47个粉尘样本共计3 982个粉尘颗粒,瓷厂样本的89%（24/27）与锡矿样本的27%（3/11）和钨矿样本的56%（5/9）存在明确的铝硅酸盐包裹,与对照样本比较,差异有统计学意义（P＜0.01）.瓷厂粉尘颗粒的45%、锡矿的18%和钨矿的13%存在表面铝硅酸盐包裹.瓷厂粉尘与钨矿和锡矿粉尘表面铝硅酸盐含量的差异有统计学意义（P＜0.01）,高铝硅酸盐含量的粉尘颗粒在瓷厂、锡矿和钨矿样本中的比率分别为22%、7%和10%.结论 瓷厂工作场所粉尘颗粒表面夹杂铝硅酸盐含量高于钨矿和锡矿的粉尘,粉尘颗粒表面成分的分析对解释不同厂矿尘肺发病的差异有一定作用.     

Risk of silicosis in cohorts of Chinese tin and tungsten miners and pottery workers (II): Workplace-specific silica particle surface composition

BACKGROUND: It is hypothesized that surface occlusion by alumino-silicate affects the toxic activity of silica particles in respirable dust. In conjunction with an epidemiological investigation of silicosis disease risk in Chinese tin and tungsten mine and pottery workplaces, we analyzed respirable silica dusts using a multiple-voltage scanning electron microscopy-energy dispersive X-ray spectroscopy (MVSEM-EDS). METHODS: Forty-seven samples of respirable sized dust were collected on filters from 13 worksites and were analyzed by MVSEM-EDS using high (20 keV) and low (5 keV) electron beam accelerating voltages. Changes in the silicon-to-aluminum X-ray line intensity ratio between the two voltages are compared particle-by-particle with the 90th percentile value of the same measurements for a ground glass homogeneous control sample. This provides an index that distinguishes a silica particle that is homogeneously aluminum-contaminated from a clay-coated silica particle. RESULTS: The average sample percentages of respirable-sized silica particles alumino-silicate occlusion were: 45% for potteries, 18% for tin mines, and 13% for tungsten mines. The difference between the pottery and the metal mine worksites accounted for one third of an overall chi-square statistic for differences in change in measured silicon fraction between the samples. CONCLUSION: The companion epidemiological study found lower silicosis risk per unit cumulative respirable silica dust exposure for pottery workers compared to metal miners. Using these surface analysis results resolves differences in risk when exposure is normalized to cumulative respirable surface-available silica dust.     

Estimating historical respirable crystalline silica exposures for Chinese pottery workers and iron/copper, tin, and tungsten miners.

Collaborative studies of Chinese workers, using over four decades of dust monitoring data, are being conducted by the National Institute for Occupational Safety and Health (NIOSH) and Tongji Medical University in China. The goal of these projects is to establish exposure-response relationships for the development of diseases such as silicosis or lung cancer in cohorts of pottery and mine workers. It is necessary to convert Chinese dust measurements to respirable silica measurements in order to make results from the Chinese data comparable to other results in the literature.This article describes the development of conversion factors and estimates of historical respirable crystalline silica exposure for Chinese workers. Ambient total dust concentrations (n>17000) and crystalline silica concentrations (n=347) in bulk dust were first gathered from historical industrial hygiene records. Analysis of the silica content in historical bulk samples revealed no trend from 1950 up to the present. During 1988-1989, side-by-side airborne dust samples (n=143 pairs) were collected using nylon cyclones and traditional Chinese samplers in 20 metal mines and nine pottery factories in China. These data were used to establish conversion factors between respirable crystalline silica concentrations and Chinese total dust concentrations. Based on the analysis of the available evidence, conversion factors derived from the 1988-1989 sampling campaign are assumed to apply to other time periods in this paper. The conversion factors were estimated to be 0.0143 for iron/copper, 0.0355 for pottery factories, 0.0429 for tin mines, and 0.0861 for tungsten mines. Conversion factors for individual facilities within each industry were also calculated. Analysis of variance revealed that mean conversion factors are significantly different among facilities within the iron/copper industry and within the pottery industry. The relative merits of using facility-specific conversion factors, industry-wide conversion factors, or a weighted average of the two are discussed. The exposure matrix of the historical Chinese total dust concentrations was multiplied by these conversion factors to obtain an exposure matrix of historical respirable crystalline silica concentrations.     

金属矿山和瓷厂的粉尘及有害因素

本文为研究金属矿工和瓷厂作业工人的肺癌病因,对4类金属矿(钨、锡,铜、铁)和9个瓷厂作业环境的粉尘,30种化学元素、放射性氡子体、γ射线和17种多环芳烃(PAH)等有害因素作了现场测定,并对各厂矿的历史测尘资料进行了整理分析。结果发现粉尘浓度早期以钨矿为最高。自70年代开始,钨矿降为最低。但游离SiO_2含量以钨矿最高,瓷厂次之,铁矿最低。瓷厂粉尘分散度比矿尘低。元素结果表明,砷、镉以锡矿最高:铁、镍以铁矿最高,这些被认为致癌物和可疑致癌物元素,可能成为矿工的致癌因素之一。井下氡子体仅铜矿超标,故铜矿工肺癌高发可能受氡暴露的影响。PAH 以井下使用柴油铲运机的锡矿、铜矿、铁矿为最高。但因其接触时间不长,其致癌作用还需进一步观察。     

A nested case-control study of lung cancer among silica exposed workers in China.

In an attempt to assess whether silica induces lung cancer, a nested case-control study of 316 male lung cancer cases and 1352 controls was carried out among pottery workers and tungsten, copper-iron, and tin miners from five provinces in south central China. Exposure to dust and silica for each study subject was evaluated quantitatively by cumulative exposure measures based on historical industrial hygiene records. Measurements on confounders such as inorganic arsenic, polycyclic aromatic hydrocarbons (PAHs), and radon were also collected from the worksites. Information on cigarette smoking was obtained by interviews of the subjects or their next of kin. A significant trend of increasing risk of lung cancer with exposure to silica was found for tin miners, but not for miners working in tungsten or copper-iron mines. Concomitant and highly correlated exposures to arsenic and PAHs among tin miners were also found. Risk of lung cancer among pottery workers was related to exposure to silica, although the dose-response gradient was not significant. Risks of lung cancer were significantly increased among silicotic subjects in iron-copper and tin mines, but not in pottery factories or tungsten mines. The results of this study provide only limited support for an aetiological association between silica and lung cancer.     

A nested case-control study of lung cancer among silica exposed workers in China.

In an attempt to assess whether silica induces lung cancer, a nested case-control study of 316 male lung cancer cases and 1352 controls was carried out among pottery workers and tungsten, copper-iron, and tin miners from five provinces in south central China. Exposure to dust and silica for each study subject was evaluated quantitatively by cumulative exposure measures based on historical industrial hygiene records. Measurements on confounders such as inorganic arsenic, polycyclic aromatic hydrocarbons (PAHs), and radon were also collected from the worksites. Information on cigarette smoking was obtained by interviews of the subjects or their next of kin. A significant trend of increasing risk of lung cancer with exposure to silica was found for tin miners, but not for miners working in tungsten or copper-iron mines. Concomitant and highly correlated exposures to arsenic and PAHs among tin miners were also found. Risk of lung cancer among pottery workers was related to exposure to silica, although the dose-response gradient was not significant. Risks of lung cancer were significantly increased among silicotic subjects in iron-copper and tin mines, but not in pottery factories or tungsten mines. The results of this study provide only limited support for an aetiological association between silica and lung cancer.     

Estimating factors to convert Chinese 'Total Dust' measurements to ACGIH respirable concentrations in metal mines and pottery industries

Historical data on the dust exposures of Chinese workers in metal mines (iron/copper, tin, tungsten) and pottery industries are being used in an ongoing joint Chinese/United States epidemiological study to investigate the exposure-response relationship for the development of silicosis, lung cancer, and other diseases. The historical data include 'total dust' concentrations determined by a Chinese method. Information about particle size distribution and the chemical and mineralogical content of airborne particles is generally not available. In addition, the historical Chinese sampling strategy is different from a typical American eight-hour time-weighted average (TWA) sampling strategy, because the Chinese samples were collected for approximately 15 minutes during production so the sample could be compared to their maximum allowable concentration (MAC) standard. Therefore, in order to assess American respirable dust exposure standards in light of the Chinese experience, factors are needed to convert historical Chinese total dust concentrations to respirable dust concentrations. As a part of the joint study to estimate the conversion factors, airborne dust samples were collected in 20 metal mines and 9 pottery factories in China during 1988 and 1989 using three different samplers: 10mm nylon cyclones, multi-stage 'cassette' impactors, and the traditional Chinese total dust samplers. More than 100 samples were collected and analysed for each of the three samplers. The study yielded two different estimates of the conversion factor from the Chinese total dust concentrations (measured during production processes) to respirable dust concentrations. The multivariate analysis of variance (MANOVA) reveals that, with a fixed sampling/analysis method, conversion factors were not statistically different among the different job titles within each industry. It also indicates that conversion factors among the industries were not statistically different. However, the two estimates consistently showed that conversion factors were the lowest in the pottery industry. Average conversion factors were then calculated for each of the estimates across the industries studied. A pooled mean conversion factor, 0.25+/-0.04, was then derived for all the job titles and industries. Respirable dust levels were estimated from the historical 'total dust' concentrations collected between 1952 and 1992 by adopting the American standard.     

葡萄籽原花青素对糖基终产物诱导的内皮细胞分泌TNF-α的影响

目的观察葡萄籽原花青素(GSP)对糖基化终产物(AGEs)诱导的人脐静脉内皮细胞(HUVEC)肿瘤坏死因子-α(TNF-α)分泌及其mRNA表达的抑制作用。方法牛血清白蛋白(BSA)与葡萄糖在体外共同孵育以制备糖基化终产物(AGE-BSA),将培养的HUVEC与不同浓度的GSP(5、15、25μg/ml)预孵育4h,再加入200μg/mlAGE-BSA共同培养,分别用ELISA法测定培养上清液中TNF-α蛋白的浓度,用逆转录PCR(RT-PC)检测TNF-αmRNA的表达,用激光共聚焦显微镜检测细胞内活性氧簇(ROS)的产生。结果HUVEC用AGE-BSA刺激后能明显的增强细胞内ROS产生,并增加TNF-α蛋白分泌及其mRNA表达,与空白对照相比差异显著(P<0.001),而GSP预孵育则对AGE-BSA诱导的上述作用具有显著的抑制作用(P<0.001),并呈剂量依赖性。结论GSP可下调AGEs刺激的内皮细胞TNF-α的产生,其机制可能与抑制细胞内氧化应激有关。     

Risk of silicosis in cohorts of Chinese tin and tungsten miners, and pottery workers (I): an epidemiological study

BACKGROUND: Epidemiological evaluations of the risk of silicosis in relation to exposure to crystalline silica have raised the question of whether different types of silica dust exposures vary with respect to their ability to cause silicosis. The aim of this study is to compare the risk of silicosis among cohorts of silica dust-exposed Chinese tin miners, tungsten miners, and pottery workers and to assess whether gravimetric measurements of respirable silica dust sufficiently determine the risk of silicosis or whether other factors of exposure may play a significant role. METHODS: Cohorts were selected from 20 Chinese mines and potteries. Inclusion criteria were starting employment after January 1, 1950 and being employed for at least 1 year during 1960-1974 in one of the selected workplaces. Radiological follow-up for silicosis onset was from January 1, 1950 through December 31, 1994. Silicosis was assessed according to the Chinese radiological criteria for diagnosis of pneumoconiosis (as suspect, Stage I, II, or III). Exposure-response relationships were estimated for silicosis of Stage I or higher. Silica dust exposure was estimated in terms of cumulative total dust exposure, calculated from a workplace, job title, and calendar year exposure matrix, and individual occupational histories. Cumulative total dust exposure was converted in two steps into cumulative respirable dust exposure and cumulative respirable silica dust exposure using conversion factors estimated from side-by-side measurements conducted in 1988-89. RESULTS: The male cohorts included 4,028 tin miners, 14,427 tungsten miners, and 4,547 pottery workers who had similar onset of employment and duration of follow-up. For a given exposure level, the risk of silicosis was higher for the tin and tungsten than the pottery workers. CONCLUSION: The observed differences in the risk of silicosis among the three cohorts suggest that silica dust characteristics, in addition to cumulative respirable silica dust exposure, may affect the risk of silicosis.