苯并[a]芘、铅染毒小鼠神经毒性及脑组织细胞凋亡的研究

目的研究苯并[a]芘(BaP)、铅及其联合作用引起的小鼠神经毒性及脑组织细胞凋亡.方法将80只昆明小鼠随机分为10组,即:①未处理对照组;②溶剂(植物油)对照组;③低浓度铅(5.4 mg/L,饮水)染毒组;④高浓度铅(54 mg/L,饮水)染毒组;⑤低剂量BaP(0.5 mg/kg体重,每周4次腹腔注射)染毒组;⑥高剂量BaP(5 mg/kg体重,每周4次腹腔注射)染毒组;⑦低浓度铅 低剂量BaP联合染毒组;⑧低浓度铅 高剂量BaP联合染毒组;⑨高浓度铅 低剂量BaP联合染毒组;⑩高浓度铅 高剂量BaP联合染毒组.实验中观察记录一般情况,处理8周后测脑脏器系数,TUNEL法检测小鼠脑组织细胞凋亡率并对凋亡率与脑脏器系数进行相关分析.结果①高浓度BaP单独染毒组(0.98%)及各联合染毒组(0.95%、0.93%、0.92%、0.90%)小鼠脑组织脏器系数低于对照组(1.08%、1.08%, P＜0.05～P＜0.000 1).②除低剂量铅单独染毒组外的其余各染毒组小鼠脑组织细胞凋亡率(11.91%、18.09%、44.62%、20.12%、60.84%、52.28%、90.17%)显著高于对照组(5.89%、5.87%, P＜0.000 1). ③细胞凋亡率与小鼠脑组织脏器系数间存在负相关关系(r=-0.827 1,P＜0.05).结论①BaP、铅对小鼠均有一定的中枢毒性,两者联合作用可使毒性增强;②细胞凋亡可能是BaP引起中枢神经系统毒性的机制之一.     

Lead (Pb2+)-induced calcium oxalate crystallization ex vivo is ameliorated via inositol 1,4,5-trisphosphate receptor (InsP3R) knockdown in a Drosophila melanogaster model of nephrolithiasis

Nephrolithiasis causes severe pain and is a highly recurrent pathophysiological state. Calcium-containing stones, specifically calcium oxalate (CaOx), is the most common type accounting for approximately 75 % of stone composition. Genetic predisposition, gender, geographic region, diet, and low fluid intake all contribute to disease pathogenesis. However, exposure to environmental pollutants as a contribution to kidney stone formation remains insufficiently studied. Lead (Pb2+) is of particular interest as epidemiological data indicate that low-level exposure (BLL = 0.48–3.85 μM) confers a 35 % increased risk of developing CaOx nephrolithiasis. However, mechanisms underlying this association have yet to be elucidated. Drosophila melanogaster provide a useful genetic model where major molecular pathophysiological pathways can be efficiently studied. Malpighian tubules (MT) were isolated from either Wild-Type or InsP₃R knockdown flies and treated with oxalate (5 mM) ± Pb²⁺ (2μM) for 1 h. Following exposure, MTs were imaged and crystals quantified. CaOx crystal number and total area were significantly increased (˜5-fold) in Pb²⁺(pre-treatment) + oxalate-exposed MTs when compared to oxalate alone controls. However, CaOx crystal number and total crystal area in Pb²⁺ + oxalate-exposed InsP₃R knockdown MTs were significantly decreased (˜3-fold) indicating the role for principal cell-specific InsP₃R-mediated Ca²⁺ mobilization as a mechanism for Pb²⁺-induced increases in CaOx crystallization inset model of nephrolithiasis.     

Electrical abnormalities with St. Jude/Abbott pacing leads: A systematic review and meta-analysis

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Incorrectly placed gonad shields: Effect on CT automatic exposure correction from four different scanners

PurposeTo examine the influence of incorrectly placed gonad shields on radiation dose when performing abdominal CT with automatic exposure correction, using systems from different vendors.Methods and materialsAn anthropomorphic phantom was scanned without gonad shields, and with gonad shields placed in two different positions relative to the scan range. Dose Length Product was recorded. mA distribution in the longitudinal direction was plotted. Mean dose was compared using the t-test.ResultsThree scanners showed different increase in relative DLP according to shield position.ConclusionCare must be taken when placing lead shielding at CT and characteristics of each scanner should be known to the operator.     

Blood lead levels and risk factors in young children in France, 2008–2009

BackgroundThe exposure of children to lead has decreased in recent years, thanks notably to the banning of leaded gasoline. However, lead exposure remains a matter of public health concern, because no toxicity threshold has been observed, cognitive effects having been demonstrated even at low levels. It is therefore important to update exposure assessments. A national study was conducted, in 2008–2009, to determine the blood lead level (BLL) distribution in children between the ages of six months and six years in France. We also assessed the contribution of environmental factors.MethodsThis cross-sectional survey included 3831 children recruited at hospitals. Two-stage probability sampling was carried out, with stratification by hospital and French region. Sociodemographic characteristics were recorded, and blood samples and environmental data were collected by questionnaire. Generalized linear model and quantile regression were used to quantify the association between BLL and environmental risk factors.ResultsThe geometric mean BLL was 14.9 μg/l (95% confidence interval (CI) = [14.5–15.4]) and 0.09% of the children (95% CI = [0.03–0.15]) had BLLs exceeding 100 μg/l, 1.5% (95% CI = [0.9–2.1] exceeding 50 μg/l. Only slight differences were observed between French regions. Environmental factors significantly associated with BLL were the consumption of tap water in homes with lead service connections, peeling paint or recent renovations in old housing, hand-mouth behavior, passive smoking and having a mother born in a country where lead is often used.ConclusionsIn children between the ages of one and six years in France, lead exposure has decreased over the last 15 years as in the US and other European countries. Nevertheless still 76,000 children have BLL over 50 μg/l and prevention policies must be pursued, especially keeping in mind there is no known toxicity threshold.     

氯碘羟喹对铅暴露致大鼠海马铜相关蛋白损伤的修复作用研究

目的探讨氯碘羟喹(CQ)对铅暴露大鼠脑组织中铜相关蛋白变化的影响,为铅中毒的修复提供理论依据。方法50只雄性SD大鼠随机分为对照组、CQ组、铅暴露组、铅+CQ组及铅+CQ+VB_(12)组,每组10只。对照组和CQ组大鼠饮用0.03%乙酸钠饮水,其余3组大鼠饮用0.03%乙酸铅饮水,共9周;之后CQ组、铅+CQ组和铅+CQ+VB_(12)组大鼠腹腔注射CQ(30 mg/kg)1周。用Morris水迷宫实验检测大鼠神经行为变化,采用电感耦合等离子体质谱法测定海马中铅和铜水平,用ELISA方法检测铜相关蛋白表达,以HE染色观察海马的病理改变。结果与对照组比较,铅暴露组大鼠第3天的定位航行时间延长,穿台次数减少;海马中铅和铜含量增加,铜锌超氧化物歧化酶(Cu/Zn SOD)和铜蓝蛋白(CP)活力下降,铜伴侣蛋白(CCS、ATOX1、COX17)表达下降,差异均有统计学意义(P0.05);铅暴露大鼠海马的神经元细胞深染,细胞质凝胶。与铅暴露组比较,铅+CQ组大鼠第3天的定位航行时间、穿台次数无明显变化(P0.05);大鼠海马中铅含量下降,差异有统计学意义(P0.05),而铜含量无明显变化(P0.05)。与铅暴露组比较,铅+CQ+VB_(12)组大鼠第3天的定位航行时间明显缩短,穿台次数增加,差异有统计学意义(P0.05);海马中铅和铜含量分别比铅暴露组下降55.94%和11.29%,差异有统计学意义(P0.05)。铅+CQ组和铅+CQ+VB_(12)组大鼠海马中CP活力均高于铅暴露组,铅+CQ+VB_(12)组CCS蛋白表达水平高于铅暴露组,差异均有统计学意义(P0.05)。HE染色表明,CQ注射后铅暴露组大鼠海马中深染细胞减少。结论 CQ能够改善大鼠认知功能,这可能与改变某些铜相关蛋白的表达有关,提示CQ可用于修复铅中毒导致的神经损伤。     

A systematic review on status of lead pollution and toxicity in Iran; Guidance for preventive measures

Lead is an old environmental metal which is presented everywhere and lead poisoning is an important health issue in many countries in the world including Iran. It is known as a silent environmental disease which can have life-long adverse health effects. In children, the most vulnerable population, mental development of children health effects is of the greatest influence. Low level lead exposure can significantly induce motor dysfunctions and cognitive impairment in children. The sources of lead exposure vary among countries. Occupational lead exposure is an important health issue in Iran and mine workers, employees of paint factories, workers of copying centers, drivers, and tile making factories are in higher risk of lead toxicity. Moreover lead processing industry has always been a major of concern which affects surface water, drinking waters, and ground waters, even water of Caspian Sea, Persian Gulf and rivers due to increasing the number of industries in vicinity of rivers that release their waste discharges into river or sea. In addition, lead contamination of soil and air especially in vicinity of polluted and industrialized cities is another health problem in Iran. Even foods such as rice and fishes, raw milk, and vegetables which are the most common food of Iranian population are polluted to lead in some area of Iran. Adding lead to the opium is a recently health hazard in Iran that has been observed among opium addicts. There are few studies evaluated current status of lead exposure and toxicity in the Iranian children and pregnant women which should be taken into account of authorities. We recommend to identify sources, eliminate or control sources, and monitor environmental exposures and hazards to prevent lead poisoning.