Children's Health and the Environment—The First Herbert L. Needleman Award Lecture

Children today are exposed extensively to toxins in the environment. Prominent among these are exposures to over 70,000 synthetic chemicals, all newly developed in the past 50 years and largely untested for their hazards to children's health. Children are uniquely vulnerable to toxins, and with increasing incidence they are developing chronic, disabling, life-threatening diseases known or suspected to be of environmental origin–asthma, endocrine disruption, cancer, and the diseases caused by tobacco. Pediatricians need to consider toxic etiologies in the differential diagnosis of childhood illness.     

ROC曲线在评价铅中毒指标中的应用

目的评价几种铅中毒指标筛选不同水平职业性铅接触的准确性。方法连续性收集１５７名铅接触工人的血标本,同时测定血铅、红细胞游离原卟啉（ＦＥＰ）、锌原卟啉（ＺＰＰ）、尿铅、尿δ氨基酮戊酸（δＡＬＡ）,以血铅≥４０、≥６０μｇ／ｄｌ的铅接触水平为金标准,用ＲｅｃｅｉｖｅｒＯｐｅｒａｔｉｎｇＣｈａｒａｃｔｅｒｉｓｔｉｃ（ＲＯＣ受试者工作特征）曲线分析软件评价所测定指标筛选血铅≥４０、≥６０μｇ／ｄｌ职业性铅接触的价值,在ＲＯＣ曲线上制定各测定指标筛选上述２个铅接触水平的最佳临界点,用ＥＰＩＮＦＯＲ统计软件比较筛选血铅≥４０、≥６０μｇ／ｄｌ的平行试验的敏感度。结果筛选血铅≥４０、≥６０μｇ／ｄｌ的铅接触水平,ＲＯＣ曲线下的面积（ＡＵＣＲＯＣ）最大的是ＺＰＰ,其他依次为ＦＥＰ、尿铅、尿δＡＬＡ;联合ＺＰＰ与ＦＥＰ的平行试验的敏感度高于联合尿铅与尿δＡＬＡ的平行试验。结论筛选血铅≥４０、≥６０μｇ／ｄｌ水平的职业性铅接触,ＺＰＰ的准确性最高,并且联合ＺＰＰ与ＦＥＰ的平行试验的敏感度高于联合尿铅与尿δＡＬＡ的平行试验。     

上海市静安区(部分)儿童血铅水平状况调查

目的了解本地区儿童血铅水平现状。方法于１９９７年８月对静安区４３７例１４个月～５岁８个月的儿童进行血铅水平测定,并对每个入选儿童进行问卷调查,问卷涉及有关儿童个人情况及家庭、社会、环境等问题。结果４３７名儿童血铅水平从１５μｇ／Ｌ至６９７μｇ／Ｌ,血铅水平均数为９７．０４μｇ／Ｌ,其中血铅水平≥１００μｇ／Ｌ有１６７例,占３８．２％。本区儿童血铅水平低于工业区,高于远郊乡村,差异有显著性意义,小儿每日在马路上的时间长短为诸多影响因素中突出并存在显著性差异的因素。结论静安区虽为非工业区,但目前情况不容乐观,环境中的铅污染问题相当严重。对儿童和家长进行健康教育,规范家长和儿童的行为,是最有效、最廉价的降低儿童铅中毒患病率的方法。     

Urinary lead as a possible surrogate of blood lead among workers occupationally exposed to lead

Objectives: The aim of the present study is to investigate whether lead (Pb) in urine (Pb-U) can be a valid surrogate of lead in blood (Pb-B), the traditional biomarker of exposure to lead in occupational health. Methods: Blood and spot urine samples were collected from 258 workers of both sexes occupationally exposed to lead. The samples were analyzed for lead by graphite furnace atomic absorption spectrometry, and the correlation between Pb-B and Pb-U was examined by linear regression analysis before and after logarithmic conversion. Results: The correlation coefficient (0.824; P < 0.01) was largest when the relationship between Pb-B and Pb-U was examined with 214 cases of one sex (i.e., men) after Pb-U was corrected for a specific gravity (1.016) of urine (Pb-Usg) and both Pb-B and Pb-Usg were converted to logarithms. The geometric means (GMs) of Pb-B and Pb-Usg for the 214 men were 489 μg/l and 81 μg/l, respectively. When Pb-Usg was assumed to be 100 μg/l in this set of correlations, the 95% confidence range of Pb-B for the group mean was narrow, i.e., 543–575 μg/l (with GM of 559 μg/l), whereas that for individual Pb-B values was as wide as 355–881 μg/l. Conclusions: The correlation of Pb-U with Pb-B among workers occupationally exposed to Pb was close enough to suggest that Pb-U may be a good alternative to Pb-B on a group basis, but not close enough to allow Pb-U to predict Pb-B on an individual basis. Received: 6 April 1999 / Accepted: 17 July 1999     

儿童接触低水平铅与智能发育的关系研究

为探讨接触低水平铅是否对儿童智能发育产生影响,根据血铅值将儿童分为低血铅组（血铅＜１０μｇ／ｄｌ）和高血铅组（血铅≥１０μｇ／ｄｌ）,比较两组之间婴幼儿智能发育和学龄前儿童智力测验结果是否有差异。结果高血铅组儿童的ＰＤＩ、ＶＩＱ、ＰＩＱ和ＦＩＱ高于低血铅组。单因素分析提示血铅与ＣＤＣＣ量表中的心理运动发育指数（ＰＤＩ）以及ＷＰＰＳＩ量表中的语言智商（ＶＩＱ）、操作智商（ＰＩＱ）和总智商（ＦＩＱ）存在负相关关系,ｒ分别为－０．１４５８,－０．３３３０,－０．２３１６,－０．３１３３;高血铅组高于低血铅组。但多元回归分析显示血铅值与智能发育无相关关系,表明铅可能是阻碍儿童智能发育的一个危险因素。但当血铅水平不太高时（血铅值不高于２５μｇ／ｄｌ）的相关关系不明显。     

铅对大鼠不同脑区IEG表达的影响

为了研究即刻早期基因（ＩＥＧ）在铅的神经毒性机制中的作用,本实验应用ＦＯＳ和ＪＵＮ蛋白免疫组织化学方法对腹腔注射染铅１３ｍｇ／ｋｇ及１３０ｍｇ／ｋｇ的大鼠不同脑区ｃ－ｆｏｓ、ｃ－ｊｕｎ表达水平进行了观察。图像分析及统计检验结果表明,急性染铅２小时后,大鼠脑组织皮层、海马ＣＡ３区及小脑的ｃ－ｆｏｓ、ｃ－ｊｕｎ表达的阳性面积比［Ａａ（％）］、平均灰度或阳性细胞个数等参数与对照组相比有显著性差异（Ｐ＜０．０５）,即染铅组ＩＥＧ表达高于对照组。这一结果提示第三信使ＩＥＧ作为转录调控因子可能参与了铅对学习记忆损害的神经毒性过程。这对深入阐明铅神经毒性的分子机制提供了一定的实验依据。     

Recovery of slowed nerve conduction velocity in lead-exposed workers

Summary Maximum motor nerve conduction velocities in the median nerve (MCV) and blood lead (PbB) were repeatedly measured in 14 lead exposed workers with an initial PbB from 0.7 to 4.0 mol/kg (median 2.3 mol/kg) for a period from 3 months to 7 years: A certain dose of Calcium Disodium Ethylenediaminetetraacetic Acid (CaEDTA) was injected intravenously into most of the subjects during the period.In seven subjects, MCV improved by more than 4 m/s during the observation period which involved the first two successive measurements of MCV and PbB, but the remaining seven subjects showed the minimal alteration (within ± 4.0 m/s). The initial value of MCV was significantly slower (P < 0.01) and the decrease in PbB was significantly greater (P < 0.05) in the group of subjects having shown the improvement of MCV by more than 4 m/s.The initial value of MCV was significant in determining the alteration in MCV in multiple regression analysis and, together with the change in PbB, explained 31% of the alteration in MCV between the first two successive measurements. The initial level of PbB, dose of CaEDTA, time interval between the measurements and age played no essential part in the alteration in MCV.The alteration in MCV throughout the whole observation period in each subject significantly correlated with the concurrent change in PbB (r=–0.573, P < 0.001).     

Evaluation of studies of the relationship between blood lead and air lead

Summary An evaluation of the major studies of the effects of airborne lead on blood lead levels of male and female adult and child populations is presented. Analysis of these studies shows that the blood lead-air lead slope for adults is approximately 1.0 for both men and women. This implies that an exposure to an additional 1 g Pb/m³ of air can result in an increase of approximately 1 g Pb/100 ml of blood. The precision of the slope for adults is rarely better than ±0.5 to ±0.7 and can be as large as ±1.0. A large portion of this uncertainty in the calculated slope is due to blood lead measurement error. The slope of the blood lead-air lead response for children ranges from 0.7 to 1.4 and is approximately the same as that for adults. The accuracy of this number is less clear for children than adults due to the small data base. Many of the studies of children have been on populations living in the vicinity of smelters. It is questioned whether these data are representative of the air lead exposure of children living in urban and suburban communities.     

Relationship between lead concentration in blood and the activities of erythrocyte pyrimidine 5′-nucleotidase and delta-aminolevulinate dehydratase in the mice exposed to lead

The relationship between the activities of both pyrimidine 5-nucleotidase (Py5N) and delta-aminolevulinate dehydratase (ALA-D) in erythrocytes and the concentration of lead in blood was investigated in the mice which were given ad libitum a drinking water containing lead of 10 to 500 ppm, for 30 days.From these results, it was demonstrated that the erythrocyte PySN activity is inhibited by lead and its activity level is negatively correlated with the concentration of lead in blood (r=–0.78). In addition, it was suggested that the erythrocyte Py5N activity is a better indicator in the exposure to relatively high lead concentration while the ALA-D is a more sensitive indicator for evaluating the lead exposure of low and moderate levels.     

Motor nerve conduction velocity in asymptomatic lead workers

Summary No difference was found between the nerve conduction velocities of the ulnar nerve of 32 lead exposed workers in the mill of a lead-zinc mine, compared to that of a control group of 14 persons. The lead exposure period was 2–37 months (mean: 12.9 months).The blood lead of the exposed group was as an average (± SD): 53 ± 16 g per 100 ml compared to 11 ± 4 g per 100 ml for the control group.Further studies are needed to establish a possible dose-time-response relationship for the possible, subclinical neuropathy found by some investigators.