应用X荧光分析法测定体内骨铅含量方法初探

Ahlgren等[1]于 1976年首次报道了体内骨铅测定的方法。他们采用5 7Co作为激发源 ,记录指骨铅激发后放出的X射线 ,测定得到骨中铅的含量。国内黄士斌等[2 ]曾采用 12 5I为激发源 ,以石蜡胫骨模型测定铅放出的LX射线 ,但该方法灵敏度不高。本文采用10 9Cd作为激发源 ,探讨铅作业工人的活体胫骨铅含量测定方法。1　材料和方法1 1　骨铅X荧光体内测量系统的建立以10 9Cd作为放射源 ,用高纯锗作为探测器 ,接受铅放出的KX射线 ,信号经放大处理 ,数字转换后与计算机联结进行数据分析 ,结果以每克骨中含 μg铅表示即 μg/g。铅的K系X射线中 ,…     

湖州地区5～7岁儿童铅负荷状况调查

铅是一种具有神经毒性、对人体无任何生理功能的重金属元素，它以各种途径进入人体，当积蓄到一定水平就会构成对人体的危害。因代谢和发育上的特点，与成人处于相同环境下的儿童更易引起铅损伤而影响神经、体格、智力等方面的发育。不同组织的铅含量测定代表不同的临床意义。铅在血液中的半衰期为30d左右，成人在固定环境中低水平铅摄入，血铅非常稳定；然而在成长中的孩子，血铅可能是表现为高度不稳定，反映了铅摄入本质上的发展变化和基本变化。骨组织聚集了体内90％以上的铅负荷量，骨铅水平是反映体内慢性铅负荷状况的理想指标，但创伤性的取样方法和x射线荧光衍射法都有很大局限性。     

体内X射线荧光骨铅检测新进展

讨论了铅的危害,认为骨铅应作为铅中毒新的生物标记。介绍了体内X射线荧光(in vivo XRF)骨铅原理,比较了三类检测各类系统的优缺点,综述了检测系统新进展。     

波士顿饮用水中的铅和20年后男性骨铅含量的关系:正常衰老研究

像波士顿那样的城市中 ,一些装有铅管道的老房屋的自来水被认为是潜在性铅暴露的重要来源。随着 Kx-射线荧光仪器的出现 ,在活体测定骨骼中的铅已经成为可能 ,而骨铅含量反映累积多年的铅暴露。该文研究了 70年代测得的这些房屋早晨第一次自来水中的铅含量和 90年代仍居住于这些房屋中的、从中年到老年的男性骨骼中铅含量之间的关系。从 1976年到1977年 ,用石墨炉原子吸收分光光度法测定了 12 9名正常衰老研究参加者的家庭自来水中的铅。从 1991年～ 1995年 ,同一人群的血铅用石墨炉原子吸收分光光度法测定 ,胫骨和髌骨的铅含量则用 Kx-射…     

职业性接触停止后人体内骨胳铅浓度的下降

体内的铅90％以上蓄积在骨胳,对这样大的铅池动力学所知甚少,直接测定人骨胳铅动力学资料几乎没有。作者曾观察铅作业工人停止接触后5个月,指骨的X线荧光分析(XRF),未显示真正的铅池的存在。 骨胳铅影响血铅、骨胳可作为时间结合剂量指数,     

实验性铅染毒对大鼠体内锌含量的影响

目的　研究低剂量铅染对幼年大鼠体内锌含量的影响。方法　以 0 ,0 5,2 0g/L剂量的醋酸铅饮用水对大鼠染毒 ,8周后全部处死 ,取全血、血清及骨、脑等组织器官 ,测定其中的铅、锌元素含量。结果　大鼠体内血铅、骨铅含量均随铅染毒剂量的增加而增加 ,而骨、血及脑中锌则随之下降。高剂量组体内骨铅与骨锌呈负相关关系 ,并有显著性 ,r =0 .58,P <0 .0 5。结论　铅对大鼠体内锌代谢有影响 ,可以导致锌含量降低。     

体内骨铅含量测量的研究进展

在研究铅与健康关系时 ,通常把血铅作为铅吸收和铅接触的主要生物监测指标 ,但血铅仅反映近期接触情况。事实上 ,铅进入体内后大部分沉积于骨中 ,骨组织是体内最大的铅储存池 ,儿童铅负荷中 75 %蓄积于骨中 ,成人则占 90 %以上。骨铅水平是反映铅负荷状况的理想指标 ,骨铅可以作为累积接触的生物标志物 ,能够预测与铅接触有关的生物效应[1] 。本文综述了近十年来骨铅含量与铅毒性关系的研究进展。一、骨铅的测量骨铅含量可用原子吸收法测定 ,但只能通过取活检或尸体解剖后取样进行分析。齿铅被认为可代表机体铅负荷情况 ,仅适于换牙期儿童铅…     

铅染毒对大鼠体内锌铜元素影响研究

[目的]研究铅染毒对大鼠体内锌铜元素的影响.[方法]将SD大鼠随机分为对照组和不同剂量醋酸铅染毒实验组,用醋酸铅饮用水染毒大鼠8周,在第8周末处死全部动物.取全血、血清、骨、脑组织,测定它们中的锌铜含量以及血铅、骨铅含量.[结果]随铅染毒剂量增加大鼠血铅和骨铅含量升高,组间差异均有统计学意义(P<0.05),血清、骨、脑中的锌含量下降,高剂量组与对照组差异均有统计学意义(P<0.05),骨铜含量下降,血铜和脑铜含量升高,高剂量组与对照组差异均有统计学意义(P<0.05).[结论]铅染毒对大鼠体内锌铜元素有明显影响.     

骨铅的生物学意义

本文从骨铅的测定、代谢动力学、毒性和流行病学研究 4个方面综述近年国外有关骨铅的研究进展 ,介绍了骨铅含量与铅毒性的关系及内源性铅中毒 ,即骨铅动员对机体的影响     

铅作业工人体内铅与锌、钙的相关性

目的探讨人体内铅水平与锌、钙之间的关系。方法对728名铅作业工人体内铅、锌、钙的含量测定及相关性分析,并与696名正常人群作对照。结果铅作业工人体内铅含量与血锌、血钙含量呈高度显著性负相关关系(rZn=-0.7128,rCa=-0.8219)。结论体内铅含量的增高严重影响机体锌、钙的正常代谢,充足的锌、钙对体内铅有拮抗和排泄作用。     

Reducing bone lead content by chelation treatment in chronic lead poisoning: an in vivo X-ray fluorescence and bone biopsy study

A stained-glass artist with longstanding exposure to lead presented with neuropsychiatric symptoms. He was evaluated before and after chelation treatment by the CaNa2 EDTA lead mobilization test, iliac crest bone lead measurement, and in vivo tibial X-ray fluorescence (XRF). The three methods showed a progressive fall in body lead stores during chelation therapy in association with improvement in symptoms and a fall in blood lead and zinc protoporphyrin levels. In vivo tibial XRF is a safe, rapid, and noninvasive technique for detecting excessive body lead burdens. XRF measurement of bone lead content is a practical method for monitoring the efficacy of therapy as well as for establishing the diagnosis.     

Tibia lead levels and methodological uncertainty in 12-year-old children

In vivo bone lead measurements with 109Cd-based K-shell X-ray fluorescence (XRF) have been used to assess long-term lead exposure in adults. Tibia lead levels were measured in 210 children (106 boys, 104 girls) of 11-12(1/2) years of age in a lead smelter town and in a control (nonexposed) town. Tibia lead levels, methodological uncertainties, and models of some of the factors influencing them are presented. 109Cd-based K-shell XRF tibia lead methodological uncertainty in children is comparable to that in adults.     

In vivo X-ray fluorescence of lead in bone.

The in vivo measurement of lead in bone by K X-ray fluorescence (K XRF) is becoming an increasingly widely utilized technique for assessing long-term lead dosimetry. Several groups have already reported the development of in vivo measurement systems, the majority adopting the 109Cd/backscatter K XRF technique because of its substantial advantages in terms of a robust measurement, lower detection limit (compared with 57Co/90 degrees), absence of the need for sedation of younger subjects, and lower effective (radiation) dose when calculated according to the most recent guidelines. The advantages of the 109Cd system are primarily a consequence of the physics principles of the technique. The apparatus of each XRF technique is transportable, facilitating easy establishment of mobile laboratory facilities. More research is needed to substantiate claims made for particular XRF technologies, but both L and K XRF techniques provide the possibility of improved understanding of the body's handling of the ubiquitous toxin lead.     

Repeatability of tibia lead measurement by X-Ray fluorescence in a battery-making workforce

The purpose of this study was to remeasure in vivo tibia lead levels in a lead-acid battery manufacturing workforce measured in a previous survey and believed to be unrealistically high. Tibia lead levels were measured by K-shell X-ray fluorescence (XRF) spectroscopy in a stratified random sample (n=40) of the original study group (n=381). The repeat survey showed much lower tibia lead levels (median=54.3 microg lead/g bone mineral, compared to 217.9 microg lead/g bone mineral, n=40). Tibia lead levels were significantly correlated with duration of occupational exposure, zinc protoporphyrin levels, and cumulative blood lead index, but not with current blood lead levels. Thirty-eight of the 40 subjects underwent two consecutive tibia lead measurements to assess the test-retest repeatability of the XRF tibia lead measurement technique. The intraclass correlation coefficient between repeated measurements was 0.926 (P=0.0001). Three measurement pairs differed by more than 20 microg/g. There was no fixed or proportional bias between the two sets of measurements. We conclude that the technique offers a highly repeatable measurement of tibia bone lead. However, care needs to be taken to avoid contamination when performing measurements on active lead workers.     

Validation of X-ray fluorescence-measured Swine femur lead against atomic absorption spectrometry.

The aim of this study was to apply the technique of (109)Cd-based K-shell X-ray fluorescence (XRF) bone lead measurements to swine femurs and to validate the concentrations obtained therefrom against an independent chemical measurement of bone lead: atomic absorption spectrometry (AAS). The femurs ranged in lead concentration from 1.0 to 24.5 microg of lead per gram of ashed bone, as measured by AAS. On average, XRF overestimated AAS-measured femur lead by 2.6 microg/g [95% confidence interval (CI), 1.1-4.0 microg/g], approximately 2 microg/g poorer than that observed in studies of human tibiae. Measurements of swine femur and, by extension, of nonhuman bones may require adjustment of the XRF spectrum peak extraction method.     

Lead exposure and spine bone mineral density

OBJECTIVE: The purpose of this study was to assess changes in spine BMD over time in relation to changes in bone and blood lead levels and baseline risk factors among female former smelter workers in Bunker Hill, Idaho. METHODS: Spine BMD was measured using Norland XR-26 X-Ray bone densitometer. Cd109 K XRF system was used to estimate tibia bone lead content. Blood lead levels were analyzed using graphite furnace atomic absorption with Zeeman effect background correction. Information about risk factors was obtained through a questionnaire. RESULTS: In the final backward stepwise multivariate regression model after controlling for baseline BMD, baseline blood lead measured in 1994 and time since menopause; spine bone density in 2000 decreased with increasing blood lead levels in 2000 in all these women, especially if they worked in a technical job (miner) most of the time at the smelter. CONCLUSIONS: Blood lead may adversely affect bone mineral density.     

In vivo bone lead measurements: a rapid monitoring method for cumulative lead exposure

Lead concentrations (microgram/g wet weight) in human bone (tibia) were measured noninvasively in vivo employing an X-ray fluorescence technique. Forty-five workers who had been subjected to chronic industrial exposure were found to have a mean bone lead content of 52.9 micrograms/g wet weight (0 to 198 micrograms/g). In addition to bone lead content, blood lead, body burden of lead as assessed by urinary lead excretion after EDTA chelation, zinc protoporphyrin, and unstimulated urinary lead excretion were evaluated. The results suggest that the in vivo measurement of tibia lead content may serve as an acceptable indicator of body lead burden and provide a practical technique for lead screening purposes. The correlation coefficient between X-ray fluorescence findings and lead excretion following Ca-EDTA administration is 0.69; p less than 0.001.     

Current problems of epidemiology and toxicology of the occupational action of lead (review of the literature)

The focus of current research on industrial lead toxicity is on the definition of dose-response relationships, particularly++ at low levels of exposure. Major interest surrounds the development of biochemical and physiologic markers of subclinical toxicity. Need exists to better delineate the toxicity of lead on the peripheral and central nervous system the kidneys, the cardiovascular system and the reproductive organs. To obtain more accurate information on cumulative individual exposure to lead, future research on lead toxicity will increasingly utilize X-ray fluorescence (XRF) analysis for determination of the lead content in bone.