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铅是有毒的环境污染物,被世界卫生组织列为十大危害公共卫生安全的化学物质之一. 环境铅污染主要来源于工业生产和应用. 尽管从20世纪末开始,全世界各个国家先后禁止使用含铅汽油以及含铅钢管和硬聚氯乙烯(PCV)塑料管材,但是由于社会工业的快速发展,铅的使用量仍然逐年增加. 根据2021年3月Statista研究部门的数据统计,全球铅消费量从2004年至2020年由7297万吨增加至11545万吨[1],增长了58.2%,其主要应用领域是铅蓄电池生产,是铅总消费量的80%左右[2]. 铅蓄电池的生产及回收过程使得铅以蒸气和烟尘形式逸散在空气中,并通过呼吸摄入方式进入人体肺部,进一步进入血液循环系统. 当血液中铅含量超过正常范围(400 mg·L−1)[3],可引起铅中毒.
铅中毒已被认为是重大的公共健康问题,尤其在发展中国家. 铅可以随着血液循环转移至身体全身的各个组织器官[4-5],引起神经系统、造血系统、肾脏系统、心血管系统、生殖系统以及骨骼系统等病变[6]. 大脑的中枢神经系统是铅毒性最敏感的器官,与神经退行性疾病(比如阿尔兹海默症)的发生密切相关[7]. 铅暴露对儿童的大脑发育系统具有更显著的毒性效应. 大量研究表明,儿童铅中毒可引起大脑发育障碍、认知能力和智商降低等症状,且这种毒性效应具有持久性甚至永久性[8-9]. 铅对生殖系统具有毒性损伤作用,对男性常见的危害包括降低精子运动性能、减少精子数量、损伤染色体,导致不育、前列腺功能异常和血清睾酮变化等,对女性的危害包括患不孕症、流产、胎膜早破、妊娠高血压和早产等[10]. 此外,孕期铅暴露可直接影响胎儿的正常发育,可能会改变大脑中髓鞘形成的时间,对儿童后期的学习或其他认知功能产生长期的有害影响[11-12]. 综上,铅中毒可严重危害人体健康.
驱铅治疗可以缓解铅中毒的损伤效应. 依地酸二钠钙(CaNa2EDTA)是目前常用的驱铅治疗药物,其原理是利用EDTA与铅离子发生络合反应,形成稳定的水溶性依地酸铅,从而通过肾脏系统随尿液排出[13]. 但是目前临床上铅中毒患者在治疗过程中铅的脱除效率较低,血液中仅部分铅通过尿液排出[14]. 此外,该方法存在血液中铅(血铅)浓度回升的现象,即在治疗初期血铅水平降低,但是一段时间后血铅浓度回升,导致治疗效果较差. 影响铅中毒患者治疗效果的因素来自多方面,可能包括用药因素和个体的生理状态等,具体的影响因素目前还有待研究.
本文以使用CaNa2EDTA进行驱铅治疗的铅中毒患者作为研究对象,分别在用药前、用药后24 h、用药后72 h对全血、血浆以及尿液中的铅含量进行检测,同时检测尿液的pH值,分析铅中毒患者在治疗过程中,血铅、血浆铅和尿铅的变化趋势以及他们的铅脱除率,进一步分析不同体系中铅脱除率与尿液pH值的相关性,进而探究驱铅治疗效果的影响因素.
铅中毒患者驱铅治疗效果的影响因素
Factors on the effect of lead-elimination treatment in lead-poisoned patients
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摘要: 铅是有毒的环境污染物,铅中毒严重危害人体健康. 静脉注射依地酸二钠钙(CaNa2EDTA)是目前临床上最常使用的驱铅治疗方法,但其治疗效果不令人满意,治疗效果的影响因素有待进一步探究. 本文以铅中毒患者作为研究对象,使用CaNa2EDTA进行驱铅治疗,分别在用药前、用药后24 h以及用药后72 h测定全血、血浆和尿液中的铅含量以及尿液的酸碱度(pH值),分析了铅中毒患者在驱铅治疗过程中,血铅、血浆铅和尿铅的变化趋势和铅脱除率,并进一步探究了影响铅脱除率的因素. 实验结果显示,随着用药治疗,血铅和血浆铅逐渐降低,同时尿铅升高;血浆铅的脱除率显著高于血铅,说明血浆铅与EDTA的络合效率高于血细胞中铅;尿铅与血浆铅呈正相关关系,而与血铅的相关性较弱,说明血浆铅是影响驱铅治疗效果的重要因素;用药后24 h,尿液pH值与血铅脱除率呈显著正相关关系,说明尿液酸碱度可能是影响驱铅治疗效果的重要参数. 本研究为提高铅中毒患者驱铅治疗效果提供了重要依据.Abstract: Lead (Pb) is a toxic environmental pollutant, and Pb poisoning seriously threatens human health. The most commonly used Pb-eliminating treatment in clinical practice is intravenous injection of calcium disodium edetate (CaNa2EDTA). However, the therapeutic effect is unsatisfactory, and the factors that influence it need to be investigated further. Pb-poisoned patients were used as research subjects in this paper and CaNa2EDTA was used in the Pb-eliminating treatment. The Pb concentration in whole blood, plasma, urine, and urine pH were all measured before medication, as well as 24 and 72 hours later. The changing trend of blood Pb, plasma Pb, urine Pb, and their Pb elimination rate during Pb-eliminating treatment and the factors influencing Pb elimination rate were investigated. The results showed that the elimination rate of plasma Pb was significantly higher than that of blood Pb, indicating that the complexation efficiency of plasma Pb and EDTA was higher than that of Pb in blood cells. Urine Pb was found to be positively related to plasma Pb, whereas the correlation between urine Pb and blood Pb was weak, indicating that plasma Pb is an important factor influencing the treatment effect of Pb elimination. The urine pH was found to be positively correlated with the blood Pb elimination rate 24 hours after medication, indicating that urine pH could be an important factor influencing the therapeutic effect of Pb elimination. This study provides an important basis for improving the therapeutic effect of Pb poisoning.
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Key words:
- Pb poisoning /
- treatment effect /
- factors /
- plasma Pb /
- blood Pb /
- urine Pb /
- pH.
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表 1 铅中毒患者的统计数据
Table 1. Demographic data of the participants
年龄
Age身体质量指数/(kg·m−2)
Body mass index男
Male女
Female40.2 ± 7.2 22.4 ± 2.3 19 (79.2%) 5 (20.8%) -
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