铅作业工人肾损害早期指标研究

目的：探讨铅作业工人肾脏损害的早期指标及其临床意义。方法：80名铅作业工人分为铅接触正常组、铅吸收组、慢性轻度铅中毒组,并以无铅接触史的43名健康成人作为对照组。分别测定血铅(PbB)、尿铅(PbU)、血红细胞游离原叶啉(FEP)、尿δ—氨基酮戊酸(δ-ALA)、尿β2-微球蛋白(β2-MG)、尿N-乙酰-β-D氨基葡萄糖苷酶(NAG)、尿视黄醇结合蛋白(RBP)。结果 铅作业工人PbB、PbU、H0、δ-ALA、NAG、RBP均显著高于对照组;β2-MG虽亦高于对照组,但差别无显著性。结论:长期职业性铅接触可造成肾功能损害,尿NAG、RBP可作为铅中毒肾损害早期敏感的监测指标。     

铅接触工人δ-氨基酮戊酸脱氢酶基因多态性研究

目的了解铅作业工人的δ-氨基酮戊酸脱氢酶(ALAD)基因分布并分析不同基因型与工人血铅(PbB)、临床症状表现的关系.方法用聚合酶链反应-限制性长度多态分析法分析不同ALAD基因型与PbB、工人症状表现的关系,比较预防措施实施前后含ALAD2型等位基因工人PbB等指标的变化.结果铅作业工人176人ALAD基因分布呈现多态现象,ALAD1-1型占89.77%,ALAD1-2型占10.23%.ALAD1等位基因比例为94.88%,ALAD2等位基因比例为5.12%,等位基因分布频率符合遗传学Hardy-Weinberg平衡.含ALAD2等位基因的个体较ALAD1型等位基因的个体具有较高的PbB浓度、较明显的神经征表现,采取措施后含ALAD2等位基因的18名工人的PbB、尿δ-氨基酮戊酸(δ-ALA)、锌原卟啉(ZPP)值有明显的降低,PbB平均下降19.06%,δ-ALA平均下降18.64%,ZPP平均下降15.88%.结论相同职业性铅接触条件下,ALAD2等位基因个体的PbB浓度增加并出现一些临床症状表现,通过采取针对性防护对策,可降低工人PbB浓度,保护含ALAD2等位基因的个体.     

δ-氨基酮戊酸脱水酶活性和含量的研究

已知铅可影响δ-氨基酮戊酸脱水酶(ALAD)。通常的方法是测定酶的活性来评价铅接触。作者用免疫分光光度法直接测定血液中酶含量,并与其它指标进行了对比,提出了铅中毒ALAD变化的作用机制。调查了30名无铅接触史的对照者和40名蓄电池厂的铅接触工人。结果如表1所示。血铅(PbB)和锌卟啉(ZPP)升高的接触组,ALAD活性显著低于对照,但激活后的酶活性升高;ALAD含量也是接触组升高;血红蛋白则两组间无差别。ALAD活性与PbB呈负相关(r=     

低浓度铅作业工人全血δ—ALAD的测定(摘要)

为探讨接触低浓度铅作业工人全血δ—氨基酮戊酸脱水酶(δ—ALAD)的变化,以观察这一指标的敏感度,我们用对—二甲氨基甲醛显色法测定某铅锌矿145名工人全血δ—ALAD活力,同时调查了现场劳动卫生情况,以及尿铅、尿粪卟啉、尿氨基酮戊酸(ALA)等,并以当地35名非铅作业者作对照。     

职业性铅接触危害的研究

本文调查了接触铅烟平均浓度为0.578mg/m~3的蓄电池厂工人53名,0.0015mg/m~3的小焊锡工52名以及0.0006mg/m~3的对照组绣花工50名。从临床症状与生化指标来看,蓄电池厂工人已受到了一定程度的铅危害,小焊锡工与对照组工人相比未见异常,可见铅的毒性危害呈明显的剂量-反应关系。铅的毒性早期症状为中枢神经系统功能紊乱、消化不良和四肢肌肉关节酸痛等。本文见乏力、腹部隐痛和关节酸痛的发生数与PbB、PbU及ZPP的浓度成正比,其症状阈浓度分别为30μg/dl、0.045mg/l及40μg/dl。铅接触的指标可以采用PbB、PbU、ALAD、FEP及ZPP,但作为预防性监护的过筛指标以ZPP为宜。铅接触组的正中神经运动及感觉传导速度均较对照组为慢(P<0.05)。在铅接触组工人中,传导速度的减慢与铅接触程度未见明显关系。     

长期接触铅作业工人肾功能损害探讨

［目的］探讨长期接触铅作业工人肾功能损害。［方法］选择三组接触铅作业工人（第一组为长期接铅仍在岗位的工人;第二组为长期接铅但已脱离岗位退休的工人;第三组为短期接铅的工人）和对照组同样测定血铅（Ｂ－Ｐｂ）、尿β２ －微球蛋白（Ｕ－β２－ＭＧ）、尿δ－氨基酮戊酸（Ｕ－δ－ＡＬＡ）内生肌酐清除率（ＣＣｒ）等指标。［结果］三组接铅工人的血铅浓度平均值均与对照组之间存在明显差异,第一组工人的Ｕ－β２－ＭＧ和Ｕ－δ－ＡＬＡ 浓度最高并与其他各组之间有显著性差异,而第二组与第三组此两项指标与对照组之间没有显著性差异。临床体检各组人员中均未发现有异常症状和体征。［结论］长期接触铅作业工人肾功能将受到损害,但早期的肾功能损害是可恢复的,Ｕ－β２ －ＭＧ作为肾小球早期损害指标是较为敏感的,建议将其作为接铅工人肾损控制的监护指标。     

铅对小鼠卟啉代谢及红细胞嘧啶5′-核苷酸酶的活性等生物学指标的影响

铅可引起卟啉和血红素代谢紊乱,如接触铅的人群中可出现尿δ-氨基酮戊酸(ALA)和粪卟啉(CP)的升高,红细胞内原卟啉的堆积及红细胞δ-氨基酮戊酸脱水酶(ALAD)活性的降低等。另有报道提出,催化嘧啶5′-磷酸盐水解脱磷作用的红细胞嘧啶5′-核苷酸酶(P5N)对铅的抑制是敏感的。并认为,在职业性接触铅的工人中,它的活性可以作为铅接触的一个指标。尽管如此,在动物或人群中铅接触与上面提及的生物学指标之间关系的前瞻性研究却很少报道,作者应用高效液相色谱荧光微量法,对摄入含铅饮水雄性小鼠经尿排泄ALA     

职业铅接触效应关系

调查了217名铅接触工人和68名对照者。高、中、低接触组和对照组的空气铅浓度(TWA)分别为0.164、0.031、0.010、和0.0018mg/m~3。接触组的症状计分、血铅、尿铅和卟啉代谢产物水平(如血锌卟啉、游离原卟啉、尿δ-氨基酮戊酸、粪卟啉)皆显著升高,并呈接触效应关系。锌卟啉和游离原卟啉与空气铅,血铅和尿铅较其它指标关系密切,提示可作为生物监测的替代指标。女工的铅效应较男工严重,表明其对铅毒性较男工敏感。     

化学法尿铅作为铅接触指标的价值评价

评价化学法尿铅筛选职业性铅接触的价值。收集１５７名同一铅接触工人的血标本及尿标本,同时测定血铅,悄铅,红细胞游离原卟啉,锌卟啉,尿δ－氨基酮戊酸,以血铅≥４０μｇ／ｄｌ,≥６０μｇ／ｄｌ的铅接触水平为金标准。用Ｒｅｃｅｉｖｅｒ－Ｏｐｅｒａｔｉｎｇ Ｃｈａｒａｃｔｅｒｉｓｔｉｃ曲线分析软件评价化学法尿负及其它测定指标的准确性。     

无机铅的剂量—反应关系

接触铅的剂量指标有环境接触指标—空气铅浓度;机体接触指标—血铅、尿铅、发铅、骨铅和齿铅。机体接触铅的反应指标有症状、体征;铅干扰卟啉代谢引起有关酶和中间产物的变化有ALAD、尿粪卟啉(CP—u)、尿ALA(ALA—u)、红细     

Correlation between lead in plasma and other indicators of lead exposure among lead-exposed workers

In order to clarify the bioavailability of lead in plasma (PbP), we performed a study on five workers in a Japanese factory manufacturing lead glass-based paints. Blood and urine samples were obtained over a period of 15 months, during which time the workers took it in turns to perform sifting work (with the highest level of lead exposure) for 1-month periods. A total of 75 sets of blood and urine samples were thus obtained. We determined whole blood lead (PbB), PbP, Urinary coproporphyrin (CPU), urinary -aminolevulinic acid (ALAU), urinary lead (PbU) and ALA in plasma (ALAP). In the 15 sets of samples obtained at the end of the period with a high level of lead exposure, PbP correlated significantly with ALAU, CPU, PbU and ALAP, but PbB correlated significantly only with PbU. In the 60 sets of samples obtained following a low level of lead exposure, correlation coefficients between the concentrations of PbP and of ALAU, CPU and PbU exceeded those between the concentrations of PbB and of ALAU, CPU and PbU. These findings indicate that PbP is a better dose indicator of lead biochemically available for heme synthesis and that PbU has a closer correlation with PbP than with PbB.     

常用铅中毒检测指标的三值问题

生物检测指标中的＂正常参考值＂,生物接触限值（可接受上限值）＂与＂诊断值＂,简称＂三值＂。本文复习了血铅（ＰｂＢ）、尿铅（ＰｂＵ）、原卟啉（ＥＰ）、锌原卟啉（ＺＰＰ）及尿中ＡＬＡ的有关三值资料。全国铅课题协作组通过４年（１９９１～１９９３）的调研工作,共调查了３１８８人。经用判别分析法得出上述各项指标的三值,并结合文献资料提出了我国常用铅中毒检测指标的三值建议值。通过在镇江、白银两市的验证,初步认为此建议值是可行的。     

职业性铅接触者生物学效应分析

对蓄电池厂铅作业工人的检测结果表明:铅接触者除出现卟啉代谢障碍、幼稚红细胞增多外,染色体畸变率亦高于对照组;红细胞游离原卟啉和染色体畸变在无铅中毒表现的接触工人中均有升高,提示这两项指标能灵敏地反映铅的损伤。建议增加染色体畸变分析作为健康监护指标,以观察铅作业工人的遗传学效应。本文还对血铅、尿铅与卟啉代谢指标间的关系进行了相关分析。     

Indicators of internal dose in current and past exposure to lead

Summary Chelatable lead (PbU-EDTA) is the best indicator of lead concentration at the critical organ level (indicator of dose). However, since this test is not easily applicable for the biological monitoring of lead-exposed subjects, the current practice is to determine lead in blood (PbB) and/or in urine (PbU). But these tests are indicators of exposure and not of dose. To analyze the reliability of PbB and PbU in estimating lead dose, the relationships between PbU-EDTA and PbB and between PbU-EDTA and PbU were studied in two groups of male lead workers: 48 currently exposed and 45 with past exposure to lead.In currently exposed workers the correlation between PbU-EDTA and PbB and between PbU-EDTA and PbU was very close (r = 0.85, r = 0.74, respectively); in past exposed workers the correlation with PbU-EDTA was decidedly lower for PbB (r = 0.54) and not significant for PbU (r = 0.29). In both cases the relationship between the variables was linear. In the previously exposed men, PbB displayed lower values than those found in currently exposed men.These results indicate that both PbB and PbU allow an indirect estimation to be made of the internal dose in currently exposed subjects, whereas the tests cannot be used for this purpose in subjects who have long since ceased to be exposed. In these cases chelatable lead must be determined.     

Lead and cadmium absorption among children near a nonferrous metal plant: A follow-up study of a test case

During a first survey (1974) increased lead absorption accompanied by impaired heme biosynthesis was found among children (11 yr) attending schools situated at less than 1 km (subgroup A) and 2.5 km (subgroup B) from a lead smelter.Eighteen months after major improvements had been introduced in the factory to reduce its lead emission, a second survey (1976) was carried out in the same schools (lead smelter and rural area) on other groups of children which were comparable with those of the first survey. The continuous air monitoring revealed for the lead smelter area a considerable decrease in airborne lead. The median values dropped from 3.2 to 1.2 μg Pb/m³ at less than 1 km and from 1.6 to 0.5–0.8 μg Pb/m³ at 1.5 km from the plant; in the rural area it remained unchanged at 0.3 μg Pb/m³.In order to evaluate the efficiency of the technological improvements we assessed the lead and cadmium exposure of the children by measuring lead concentration in blood (PbB) and urine (PbU), erythrocyte δ-aminolevulinic acid dehydratase (ALAD) activity, free erythrocyte porphyrin (FEP) concentration, δ-aminolevulinic acid excretion in urine (ALAU), and cadmium concentration in blood (CdB) and urine (CdU). Subgroups A and B exhibited higher PbB and CdU levels, and lower ALAD activity than the rural group; but PbU, CdB, FEP, and ALAD were significantly increased only in subgroup A. Compared with the results of the first survey, a significant tendency to a normalization of PbB was found at 2.5 km, but at less than 1 km the biological parameters (particularly PbB, ALAD, FEP) did not improve. The PbB percentile distribution in subgroup B lies now under the tentative PbB percentile distribution proposed in the PbB Directive of the Commission of the European Communities (CEC): that of subgroup A, however, is still above that of the CEC proposal. Taking into account the higher degree of vulnerability to lead exposure as compared to adults a more restrictive PbB percentile distribution has been proposed for children.Two hypotheses have been put forward to explain the lack of significant improvements in the biological parameters of the children living at less than 1 km from the lead smelter. Ingestion of dust and dirt (probably due to hand contamination) from their surroundings in the course of their normal everyday activity may represent, in addition to air, a supplementary cause of increased lead accumulation in these children. Indeed, dust and dirt samples collected on the school playgrounds at less than 1 km from the factory contained (mean ± SD) 3541 ± 1310 and 5466 ± 831 μg Pb/g, whereas at 2.5 km and in the rural area it only amounted to 397 ± 33 and 152 ± 41 μg Pb/g, respectively. The alternative explanation is that a continuous resuspension of dust and dirt particles from the highly contaminated soil around the lead smelter may maintain a very high airborne lead concentration at the breathing height of the children. In addition to a lasting reduction of lead emission from the plant, the remedial actions should also take into consideration these two possibilities.     

Occupational lead exposure of storage battery workers in Korea.

Two hundred and thirty-four lead workers employed in a storage battery factory in Korea were examined for lead in blood (PbB) and urine (PbU). delta-aminolaevulinic acid in urine (ALAU), coproporphyrin in urine (CPU), and haemoglobin. The dose-response relationship between PbB and ALAU suggested that a PbB below 50-60 micrograms/dl is a proper practical limit of biological monitoring for lead workers. The inter-relationship between PbB and ALAU or PbU was better explained by a segmental straight function than by a curvilinear function. Inclusion of data from workers whose PbB was below 30-40 micrograms/dl, if they comprise a relatively large proportion of the whole, seems to have a role as a dummy effect on the overall regression function causing the curvilinear trend. At a given blood lead concentration, the ALAU of lead workers increased with an increase in the duration of exposure. This could be explained by the chronic effect of lead on haem precursors. Semi-quantitative measurement of CPU still played an important part in the screening of lead workers due to its simplicity, showing high sensitivity (97.8%) in detecting lead workers with PbB of 60 micrograms/dl or over.     

Free erythrocyte protoporphyrin as an indicator of the biological effect of lead in adult males

Summary The relationship between FEP and the indicators of dose (PbB, PbU, PbU-EDTA) was examined in a group of male subjects who had left lead-exposing jobs more than 12 months previously.In these subjects, FEP and PbB and FEP and PbU were correlated to a distinctly lower degree compared to previous findings in currently exposed subjects, although the correlations were still statistically significant. In the previously exposed subjects the erythrocyte metabolite displayed definitely higher values than those found in currently exposed subjects at the same PbB or PbU levels.A very close correlation was found between FEP and PbU-EDTA, as was found in exposed subjects. The regression curve assumed an identical profile in the two situations. From these results it may be concluded that FEP persists at high levels for a long time after cessation of exposure due to a direct inhibition of heme synthetase caused by lead released from the tissue deposits.It should be noted that FEP proved to be a valid test for predicting the amount of lead storage, even a long time after cessation of exposure.Abbreviations PbB blood lead (g/100 ml) - PbU lead in urine (g/l) - PbU-EDTA amount of chelatable lead excreted with 24 h urine after administration of Ca NA₂ EDTA (1 g intravenously) - FEP free erythrocyte protoporphyrin (g/100 ml RBC) - ALAU urinary delta-aminolevulinic acid (mg/l) - CPU urinary coproporphyrin (g/l)     

Comparison of measures of lead exposure, dose, and chelatable lead burden after provocative chelation in organolead workers.

OBJECTIVES--To describe 6 h urinary lead excretion (6 h PbU) after 1 g intravenous ethylene diamine tetraacetic acid (EDTA) in organolead manufacturing workers with mixed exposure to organic and inorganic lead; to determine the predictors of lead excretion (PbU); and to determine the extent to which internal lead stores and ongoing external exposure govern blood concentrations of lead (PbB). METHODS--A case series of 21 active workers were studied. Personal industrial hygiene data, grouped by 29 exposure zones, in combination with personal interviews about work location and times were used to derive several measures of recent and cumulative exposure to organic and inorganic lead. The average exposure intensities assigned to the 29 zones ranged from 4 to 119 micrograms/m3 (0.02-0.57 mumol/m3 as lead) for organic lead and from 1 to 56 micrograms/m3 (0.004-0.27 mumol/m3) for inorganic lead. RESULTS--After controlling for age, 6 h PbU was significantly and positively correlated with summary measures of PbB--for example, lifetime peak PbB, time weighted PbB--and zinc protoporphyrin concentrations--for example, lifetime peak zinc protoporphyrin, time weighted zinc protoporphyrin--but not with measures of estimated external exposure--for example, duration of exposure and cumulative exposure to inorganic or organic lead. Among workers with higher chelatable lead burdens (6 h PbU > or = 212.4 micrograms (1.03 mumol) divided at the median), there was no apparent relation between recent inorganic lead exposure and PbB at the time of chelation. Among workers with lower chelatable lead burdens (6 h PbU < 212.4 micrograms (1.03 mumol) however, there was a significant relation between exposure and effect between recent exposure to inorganic lead and PbBs. CONCLUSION--These findings are consistent with the concept of physiological dampening. The high chelatable lead burden, a source of internal exposure, dampens the effect of external exposure on PbBs. The data suggest that in organolead workers with high chelatable lead burdens, PbBs may be more influenced by internal lead stores than by variations in airborne exposure to organic and inorganic lead.     

Investigation and evaluation of zinc protoporphyrin as a diagnostic indicator in lead intoxication

To evaluate the utility of zinc protoporphyrin (ZPP) as an indicator of lead exposure, we examined 128 workers employed at a battery storage plant and two smelters, 343 persons who lived within 200 m of the plants, and 217 controls. Based on Chinese criteria, the “normal” ZPP value among inhabitants of Shaanxi Province was determined to be 85 μg/100 ml. ZPP proved to be a more sensitive and specific indicator of lead exposure, at both high and lower levels, than PbB or PbU. Among 115 patients who underwent chelation therapy for lead poisoning, ZPP also proved to be a valid index of recovery. © 1993 Wiley-Liss, Inc.