Reversal learning deficits in young monkeys exposed to lead.

The reversal learning capacity of young rhesus monkeys in visual discrimination tasks was examined during daily exposure to dietary lead acetate throughout the first year of life. While not affected in physical development, all lead-treated monkeys showed performance deficits on reversal learning tasks. These deficits were independent of lead-induced changes in motivation. Over a series of problems, the overall learning rate of monkeys with blood lead concentrations in the range of 70-90 microgram/dl was retarded, which resulted partly from a pronounced difficulty in attaining criterion on the first of a series of reversals within a given problem. This latter deficit resulted from an increase in errors, balks, and total trials to criterion on the first reversal. Monkeys exposed to blood lead concentrations of 40-60 microgram/dl required significantly more trials to finish all problems, but did not show the first-reversal deficit. Theoretical implications of these data were discussed.     

Effect of short-term administration of lead to pregnant rats.

Lead was administred to adult female rats in drinking water (0;0.1:1 and 10 ppm) for 3 weeks before mating, during pregnancy and during 3 weeks after delivery. On day 21 after delivery the mothers and their newborns were sacrified and various parameters of blood -- lead concentration on (Pb-B), hematocrit (Htc), hemoglobin (Hb), free erythrocyte porphyrins (FEP), delta0aminolevulinate dehydratase (ALAD) -- and tissue -- ALAD, free tissue porphyrins (FTP), lead concentration (Pb-T) -- were determined. In mothers a significant increase in Pb-B and Pb concentration in kidney was found in the 10 ppm group, but this increase in lead concentration was not associated with any statistically significant modification of the biochemical parameters. In newborns, lead concentration in blood and in kidney was also significantly increased in the 10 ppm group and this lead exposure was associated with a decrease of the ALAD activity in blood and an increase of FTP in kidney. On the basis of the biochemical parameters investigated one can therefore conclude that the developing organism is more susceptible to the biological action of lead than the organism of adult animals and that the "no-effect" level of lead administered during pregnancy and in the neonatal period is around 1 ppm.     

Chlorinated pesticides and heavy metals in human semen

The concentration of chlorinated pesticides and heavy metals (lead and cadmium) was measured using gas liquid chromatography and the graphite tube atomizer of atomic absorption spectrophotometer, respectively, in semen samples collected from men in the normal human population. Significant concentrations of lead and cadmium were detected. Significant amounts of hexachlorocyclohexane (HCH) and its isomers alpha, beta, gamma and delta, the dichlorodiphenyl trichloroethane (DDT) metabolite 1,1,1-trichloro-2,2-bis (p chlorophenyl ethane) (pp'-DDE) and low values of 1,1,2-dichloro-2, 2-bis(p chlorophenyl ethane) (pp'-DDD) aldrin or endosulfan were detected. The presence of these xenobiotics in human semen might be related to the extensive use of pesticides, emission of exhaust from motor vehicles, consumption of tobacco and industrial operations.     

大鼠脑铅和血铅含量对学习记忆的影响与硒锌的保护作用

目的　探讨食物铅进入机体后对记忆功能的影响以及补充锌和硒对铅致损伤的保护作用。方法　将Wistar大鼠按体重随机分为 10组 ,在基础饲料里分别添加不同剂量的亚硒酸钠、乳酸锌及醋酸铅 ,实验期为 12周。结果　染铅各组大鼠的脑和全血中铅含量均显著高于对照组。在染铅各组中 ,从低硒缺锌到高硒高锌组大鼠的脑铅含量呈下降趋势 ,对照组大鼠的脑铅含量未检出。染铅各组大鼠血铅含量也不同程度地受饲料中硒和锌水平的影响 ,硒和锌对降低脑铅含量有协同作用 (P <0 0 0 1)。各组大鼠发生错误次数和到达终点所需时间明显不同 ,缺锌低硒染铅组发生的错误次数和所需时间显著高于其他染铅各组和对照组(P <0 0 5 ) ;补硒可显著改善染铅大鼠水迷宫实验所需时间和降低错误次数 (P =0 0 0 2和P =0 0 0 7)。大鼠水迷宫试验中随着脑铅和血铅含量的增加 ,到达终点所需时间延长和发生的错误次数增加。结论　良好的锌和硒营养状况有助于降低组织中铅的水平 ,提示可能具有拮抗铅毒性的作用     

锂的神经元保护作用及对铅神经毒性的拮抗效应

目的　探讨铅的神经毒性、锂的神经元保护作用以及锂对铅神经毒性的拮抗效应 ,研究不同浓度氯化锂和醋酸铅对原代培养皮层神经元生长及存活的影响。方法　建立新生大鼠皮层神经元原代培养技术 ,通过加入不同浓度氯化锂、醋酸铅及同时加入 5mmol L的氯化锂和不同浓度醋酸铅 ,显微镜下观察神经细胞的生长和存活情况 ,目镜测量神经元突起长度 ,噻唑蓝 (MTT)还原法检测细胞生长活力。结果　各浓度氯化锂均可促进神经元突起生长 (P <0 0 5 ) ,1 2 5mmol L以上浓度的氯化锂可使神经元生长活力降低 (P <0 0 5 ) ;醋酸铅 (≥ 10 - 7mol L)能抑制神经元生长 ,其神经元突起长度明显短于对照组 (P <0 0 1) ,各浓度的醋酸铅均可使神经元生长活力降低 (P <0 0 1) ;5mmol L浓度的锂对染铅神经元有明显的保护作用和促生长作用 ,表现为铅浓度为 10 - 6 mol L与 10 - 5mmol L组的神经元突起长度较单纯染铅组长 (P <0 0 1) ,使铅浓度为10 - 8～ 10 - 5mol L的神经元生长活力提高 (P <0 0 1)。结论　锂有神经元保护作用 ,而铅对神经元表现出毒性效应 ;锂对染铅神经元有一定的保护作用     

δ-氨基乙酰丙酸脱水酶基因多态性对职业铅接触工人血铅和锌原卟啉的影响

[目的 ]研究δ 氨基乙酰丙酸脱水酶 (ALAD)基因多态性对职业铅接触工人血铅 (PbB)和锌原卟啉 (ZPP)的影响。 [方法 ]采集 170名上海市某蓄电池厂职业铅接触工人外周静脉血样 ,多聚酶链式反应 (PCR)和限制性内切酶 (MspⅠ )限制性片段长度多态性 (RFLP)方法进行ALAD基因分型分析 ,用PE 80 0型原子吸收分光光度计和ZPP 3 80 0型血液锌原卟啉测定仪分别测定PbB和ZPP含量 ,并分析其与基因型的关系。 [结果 ]①ALAD11纯合子基因型者有 15 4名 ,占90 5 9% ;ALAD12杂合子基因型者有 16名 ,占 9.41% ;未检出ALAD2 2纯合子基因型者 ;②ALAD1和ALAD2等位基因分布频率分别是 95 .2 9%和 4.71% ;③在同等外暴露条件下 ,ALAD12杂合子基因型组工人血铅水平 ( 1.0 4± 0 .48μmol/L)明显高于ALAD11纯合子基因型组工人血铅水平 ( 0 .78± 0 .3 4μmol/L) ,且差异有统计学意义 ;④ALAD12基因型工人锌原卟啉(ZPP)含量比ALAD11基因型者稍低 ,但差异没有统计学意义 ,前者为 ( 0 .42± 0 .2 4) μmol/L ,后者为 ( 0 .46± 0 .41) μmol/L。[结论 ]ALAD2等位基因频率与文献报道的亚洲人群的结果相近 ,符合Hardy Weinberg平衡 ,在同样职业铅暴露环境下 ,具有ALAD2等位基因的工人血铅水平增高 ,ALAD2等位基因可加重工人体内的铅     

顺德地区0～6岁儿童铅中毒及其相关因素调查

【目的】　调查顺德地区 0～ 6岁儿童铅中毒的流行率以及引起铅中毒的相关因素。　【方法】　采集 3个镇城乡共 6间托儿所、幼儿园儿童的静脉血标本 3 49人 ,新生儿之脐血标本 10 8人 ;并收集工业区污水、乡村河涌水、鱼塘水 ,乡村田边土、交通繁忙的主干道及大街边尘土 ,铅皮牙膏、药膏及塑料皮牙膏 ,汽油等标本进行铅含量检测。对每个抽血对象的家长进行相关因素问卷调查。　【结果】　铅中毒的流行率为 42 .7% ,其中农村儿童铅中毒为3 9 .4% ;城镇儿童铅中毒为 46.2 % ;脐血铅超标达 42 .6%。相关因素有 :小儿及孕妇常吃罐装食品、饮料、皮蛋 ,小儿喜欢咬玩具、吮手指、咬铅笔、进食前不常洗手 ,父母亲从事铅暴露作业 ,家住大街边及大马路边等有关。工业区污水、鱼塘水、交通繁忙的主干道及大街边尘土、铅皮牙膏、药膏的铅含量明显高于乡村河涌水、乡村田边土、塑料皮牙膏。　【结论】　铅中毒与环境污染、小儿或孕妇饮食嗜好、不良习惯、父母从事铅暴露作业以及家住大街边有关。     

牛磺酸锌对染铅大鼠海马NOS活性和nNOS蛋白及基因表达的影响

目的:探讨不同剂量牛磺酸锌(TZC)拮抗铅对大鼠海马一氧化氮合酶(NOS)活性和神经元型一氧化氮合酶(nNOS)蛋白及基因表达的损害。方法:用NADPH-黄递酶(NADPH-d)组化、ABC免疫组化和半定量逆转录-聚合酶链式反应(RT-PCR)法,研究饮用含0.2 g/L醋酸铅(PbAc)饮水和含不同剂量(5.9、17.7g/kg)TZC饲料喂养的大鼠海马NOS活性、nNOS阳性神经元数目以及nNOS基因表达的变化。结果:与对照组大鼠海马CA1区NOS、nNOS阳性神经元数(56.80±6.69,60.67±13.48)和海马nNOS mRNA相对含量(0.454±0.045)相比,染铅组大鼠海马CA1区NOS、nNOS阳性神经元数(42.60±6.1 7,46.67±9.04)和海马nNOS mRNA相对含量(0.071±0.025)明显减少(P<0.05)。而铅加5.9 g/kg TZC 组大鼠海马CA1区NOS、nNOS阳性神经元数(61.60±7.30,56.87±6.64)和海马nNOSmRNA相对含量(0.412±0.061)均较染铅组明显增加(P<0.05)。铅加牛磺酸(Tau)组和铅加17.7 g/kgTZC组海马nNOS mRNA相对含量(0.138±0.026和0.137±0.019)较染铅组明显增加(P<0.05)。各组大鼠海马齿状回NOS和nNOS阳性细胞数的变化与CA1区变化基本一致,而CA3区无明显差别。结论:5.9 g/kg TZC能明显增强慢性染铅大鼠海马NOS活性和nNOS蛋白及基因表达。     

0～6岁儿童骨密度与血清锌、铜、血铅关系的研究

【目的】　探讨 0～ 6岁儿童低骨密度与血清锌、铜、血铅的关系 ,为临床儿童低骨密度的预防提供依据。　【方法】　在本院儿保门诊 ,随机抽取己排除影响骨代谢性疾病的 0～ 6岁儿童 2 0 4名 ,用超声骨密度仪测胫骨中段骨密度 ,根据同年龄、同性别骨密度值的百分位数分成低骨密度组与正常对照组 ,同时测定血清锌、铜及全血铅。　【结果】　低骨密度组平均血清锌水平 ( 12 70 .5± 14 6.0 ) μmol/L低于对照组 ( 13 2 2 .1± 166.0 ) μmol/L ,差异有显著性(P <0 .0 5 ) ;锌缺乏患病率 ( 3 0 %)高于对照组 ( 18%) ,差异有显著性 (P <0 .0 5 ) ;低骨密度组平均血清铜值 ( 14 98.6±2 16.8) μmol/L ,稍低于对照组 ( 15 3 4.4± 2 3 0 .6) μmol/L ,但差异无显著性 (P >0 .0 5 ) ;两组铜缺乏患病率、血铅值、铅中毒患病率差异无统计学意义 (P >0 .0 5 )。　【结论】　 0～ 6岁儿童低骨密度的发生与锌缺乏有关 ,应加强儿童锌缺乏症的预防和治疗 ,以降低儿童低骨密度的发生。     

419名铅中毒儿童贫血发生率的调查

目的 :进行儿童铅中毒患儿贫血发生率的调查 ,了解铅对儿童血液系统的影响。方法 :测定 5 4 0名儿童的血铅水平(BPb) ,根据血铅水平分成非铅中毒组 (BPb<10 0μg/ L )和铅中毒组 (BPb≥ 10 0μg/ L ) ,同时对两组儿童进行血细胞分析 ,测定红细胞 (RBC)、血红蛋白 (HGB)、红细胞平均容积 (MCV)、红细胞平均血红蛋白量 (MCH)、红细胞平均血红蛋白浓度 (HCHC)水平。结果 :两组的 RBC、HGB、MCV、MCH、MCHC的水平差异无显著性 (P>0 .0 5 )。结论 :较低水平铅中毒患儿贫血发生率无显著升高。