Ⅰ和aVF导联联合Ⅱ导联法与传统Ⅰ和Ⅲ导联法判断QRS平均心电轴的比较

目的比较Ⅰ和aVF导联目测判断QRS平均心电轴与Ⅰ和Ⅲ导联判断电轴的优势。方法采用整群抽样法抽取兰州大学第二临床医学院2015级临床医学生,分为研究组和对照组,研究组用导联Ⅰ和aVF判断电轴,对照组用导联Ⅰ和Ⅲ判断电轴。判断标准依据心电图机系统化数据为参考结果。结果应用导联Ⅰ和aVF判断其中3个象限的心电轴快速准确;当电轴在“left”象限时,需要联合Ⅱ导联正负相判断。Ⅰ和Ⅲ导联误判率相对较高。结论用Ⅰ和aVF导联判断QRS平均心电轴快速准确,可用于临床。     

双心腔主动电极起搏与心房被动心室主动电极起搏的对比研究

目的:观察心房心室双螺旋主动电极在双腔心脏起搏器植入术中的有效性和安全性。方法:回顾性将90例符合双腔起搏器植入指征的患者分为心房心室双螺旋主动电极组(双螺旋电极组42例)与心房被动电极、心室螺旋主动电极组(单螺旋电极组48例)。观察2组术中及术后随访情况。结果:2组均成功植入起搏器及起搏电极。双螺旋电极组中1例孕妇零射线下完成双螺旋电极及起搏器植入;4例永存左上腔静脉患者在左侧锁骨下完成双螺旋电极及起搏器植入。双螺旋电极组和单螺旋电极组的手术时间及射线时间无显著差别,双螺旋电极组术后卧床时间显著缩短[(4.2±1.5)h vs(56.3±22.5)h,P0.05]。单螺旋电极组术中出现心房电极导线脱位3例,双螺旋电极组未见导线移位、心肌穿孔及心包填塞等情况。术后随访,2组均无电极脱落和起搏阈值升高。结论:心房心室双螺旋主动电极在双腔心脏起搏器植入术中安全可行,并不增加手术时间和射线时间,特别是应用于心腔结构异常和特殊患者,显著增加手术成功率。     

Mirror image electrocardiograms and additional electrocardiographic leads: new wine in old wineskins?

Background

Mirror image electrocardiograms (ECGs), obtained by inverting the original signals, and additional precordial leads have been proposed as means to improve ECG diagnosis. The theoretical backgrounds of these proposals are discussed.

Methods

In 746 body surface potential maps, the mirror areas of the 6 precordial leads, V₃R, and 2 more leads higher up and 1 lower down the thorax have been determined. The similarity between the original signal and its mirror image was expressed by a similarity index. This was done separately for QRS and ST-T; for the first and second parts of QRS; and for the categories normal, left ventricular hypertrophy, and infarct.

Results

In general, high similarity scores were obtained. The mirror images of V₁ and V₂ are almost diametrically located on the back. Inverting these leads could render the V₈ and V₉ leads. The other mirror areas may deviate considerably from where generally expected.

Conclusion

Mirror images can be obtained consistently from all locations, supporting the dipole representation of cardiac electrical activity. Neither mirror image ECGs nor additional chest leads contribute essentially to ECG diagnosis.     

Risk of leukemia in relation to exposure to ambient air toxics in pregnancy and early childhood

There are few established causes of leukemia, the most common type of cancer in children. Studies in adults suggest a role for specific environmental agents, but little is known about any effect from exposures in pregnancy to toxics in ambient air. In our case–control study, we ascertained 69 cases of acute lymphoblastic leukemia (ALL) and 46 cases of acute myeloid leukemia (AML) from California Cancer Registry records of children <age 6, and 19,209 controls from California birth records within 2 km (1.3 miles) (ALL) and 6 km (3.8 miles) (AML) of an air toxics monitoring station between 1990 and 2007. Information on air toxics exposures was taken from community air monitors. We used logistic regression to estimate the risk of leukemia associated with one interquartile range increase in air toxic exposure. Risk of ALL was elevated with 3^rd trimester exposure to polycyclic aromatic hydrocarbons (OR = 1.16, 95% CI 1.04, 1.29), arsenic (OR = 1.33, 95% CI 1.02, 1.73), benzene (OR = 1.50, 95% CI 1.08, 2.09), and three other toxics related to fuel combustion. Risk of AML was increased with 3rd trimester exposure to chloroform (OR = 1.30, 95% CI 1.00, 1.69), benzene (1.75, 95% CI 1.04, 2.93), and two other traffic-related toxics. During the child's first year, exposure to butadiene, ortho-xylene, and toluene increased risk for AML and exposure to selenium increased risk for ALL. Benzene is an established cause of leukemia in adults; this study supports that ambient exposures to this and other chemicals in pregnancy and early life may also increase leukemia risk in children.     

某铅酸蓄电池生产企业通风设施评价及改造

目的了解某铅酸蓄电池生产企业多年来频发职业性铅中毒的原因,探讨有效措施降低铅中毒的发病率。方法对某铅酸蓄电池生产企业进行职业病危害因素检测,对通风设施进行评价与改造。结果该企业原作业场所铅监测点的超标率为62．9％,最高点超标207倍;工种的超标率为64．6％,最高超标139倍;通风不良的排风口占72．0％,主要是通风管道堵塞或破损,造成控制风速不达标。对原有通风设施进行重新疏通,更换排铅烟管道,更新铅尘除尘器的过滤袋。改造后作业场所铅监测点的超标率下降为13．2％,最高浓度超标5倍。企业铅中毒新发病例数由每年17例下降为每年3例。结论该企业由于通风系统维护不当造成作业场所空气中铅浓度严重超标,导致铅中毒发病率较高,对通风系统改造后,作业场所铅浓度明显改善,铅中毒患者减少。     

铅中毒对儿童注意力缺陷多动障碍影响研究的meta分析

目的综合评价铅中毒对儿童注意力缺陷多动障碍的影响。方法采用meta分析方法,对1992—2012年关于铅中毒与儿童注意力缺陷多动障碍相关的病例对照研究的文献进行分析。结果纳入6篇病例对照研究文献,累计病例数为1 440例,对照组1 388例。结果显示,铅中毒与儿童注意力缺陷多动障碍的发生关联明显（Z=4.52,P〈0.05）,合并OR值为2.91,OR 95%CI为1.83-4.62。结论铅中毒是儿童注意力缺陷多动障碍的一个危险因素,会增加儿童患注意力缺陷多动障碍的概率。     

安徽省歙县某蓄电池厂工人血铅水平调查结果

目的了解安徽省歙县蓄电池厂铅作业工人的血铅水平,以便采取科学有效的防护措施。方法采用石墨炉原子吸收法测定血铅含量并进行统计分析。结果 311名作业工人当中,血铅检测最低为14μg/L,最高为647μg/L,平均（292.4±161.5）μg/L;血铅≥400μg/L共有78人,超标率为25.1%,其中有6人超过了诊断值;不同性别、不同工龄及不同岗位之间工人血铅超标率差异均有统计学意义（P﹤0.01）。结论该企业工人血铅超标率仍处于较高水平,铅危害情况比较严重,因此应进一步加强监管力度,改进生产工艺,改善工作环境,规范和完善职业危害防护设施,加强对工人的职业危害宣传教育,提高工人自我防护意识,切实保护劳动者的身体健康。     

Latent role of in vitro Pb exposure in blocking Aβ clearance and triggering epigenetic modifications

Both β-amyloid (Aβ) catabolism and epigenetic regulation play critical roles in the onset of neurodegeneration. The latter also contribute to Pb neurotoxicity. The present study explored the role of epigenetic modifiers and Aβ degradation enzymes in Pb-induced latent effects on Aβ overproduction in vitro. Our results indicated that in SH-SY5Y cells exposed to Pb, the expression of NEP and IDE remained declined during the recovery period, accompanied with abnormal increase of Aβ_1-42 and amyloid oligomer. A disruption of selective global post-translational histone modifiers including the decrease of H3K9ac and H4K12ac and the induction of H3K9me2 and H3K27me2 dose dependently was also showed in recovery cells. Moreover, histone deacetylase inhibitor VPA could attenuate latent Aβ accumulation and HDAC activity induced by Pb, which might be by regulating the expression of NEP and IDE epigenetically. Overall, our results suggest sustained reduction of NEP and IDE expression in response to Pb sensitizes recovery SH-SY5Y cells to Aβ accumulation; however, administration of VPA is demonstrated to be beneficial in modulating Aβ clearance.     

Variability of magnetoencephalographic sensor sensitivity measures as a function of age,brain volume and cortical area

Objective

To assess the feasibility and appropriateness of magnetoencephalography (MEG) for both adult and pediatric studies, as well as for the developmental comparison of these factors across a wide range of ages.

Methods

For 45 subjects with ages from 1 to 24 years (infants, toddlers, school-age children and young adults), lead fields (LFs) of MEG sensors are computed using anatomically realistic boundary element models (BEMs) and individually-reconstructed cortical surfaces. Novel metrics are introduced to quantify MEG sensor focality.

Results

The variability of MEG focality is graphed as a function of brain volume and cortical area. Statistically significant differences in total cerebral volume, cortical area, MEG global sensitivity and LF focality are found between age groups.

Conclusions

Because MEG focality and sensitivity differ substantially across the age groups studied, the cortical LF maps explored here can provide important insights for the examination and interpretation of MEG signals from early childhood to young adulthood.

Significance

This is the first study to (1) investigate the relationship between MEG cortical LFs and brain volume as well as cortical area across development, and (2) compare LFs between subjects with different head sizes using detailed cortical reconstructions.     

Blood lead and cadmium levels in children: A study conducted in Changchun,Jilin Province,China

OBJECTIVES:

Exposure to lead and cadmium in developing countries is considered to be a public health emergency. The present study was designed to investigate children’s exposure to lead and cadmium in Changchun, China.

METHODS:

A total of 1619 blood samples were collected at random from 1426 children between one and 14 years of age, and 204 adults from Changchun, China. Blood lead and cadmium levels were determined using atomic absorption spectrophotometry.

RESULTS:

The average blood lead level in children was 60.29 μg/L, with boys exhibiting higher blood lead levels than girls. The average blood cadmium level in children was 1.26 μg/L, and differences were not observed between boys and girls.

CONCLUSIONS:

Children from Changchun exhibited relatively low blood lead and cadmium levels compared with children from other cities, and higher lead and lower cadmium levels than adults. This may be related to leaded gasoline environmental pollution and children’s hand-to-mouth activities.