Subclinical effects of environmental hazardous factors on nervous and renal functions in humans

本研究的目的是阐明铅、镉和甲基汞(MeHg)等环境危险因素对人类神经和肾功能的亚临床影响。(1)采用基准剂量(BMD)法估算铅对工人神经运动功能影响的临界剂量。对血铅水平为6~89μg/dl的121名铅作业工人和60名非接触铅作业工人的姿势摆动参数进行了光谱分析比较。除张开眼睛的矢状摆动外，所有的摆动参数，在铅作业工人中都明显大于对照组。体位摆动的临界剂量为12.1~17.3μg/dl。(2)为了探讨头发、趾甲和尿中总汞水平之间的关系以及甲基汞摄入对肾小管功能的潜在影响，对其进行了尿N-乙酰-氨基葡萄糖苷酶活性(NAG)和α-1-微球蛋白(AMG)的…测定。59名妇女的汞摄入量更高，并使用食物频率问卷估计鱼和其他海产品的每日汞摄入量。头发、趾甲和尿中THG水平分别为1.5 1±0.91(SD)μg/g、0.5 9±0.32μg/g和0.86±0.6 6μg/g肌酐，三者之间呈正相关。汞的日摄入量为9.15±7.84μg/d，与头发、趾甲和尿液中的THG水平显著相关。在女性中，NAG和AMG与每日汞摄入量以及头发、脚趾甲和尿中的THG水平均呈正相关；当使用多元回归分析调整可能的混杂因素时，这些关系几乎相似，如尿镉(0.47±0.28μg/gCre)。总而言之，食用鱼类产生的甲基汞可以在一定程度上解释头发、脚趾甲和尿液中的总汞水平，部分是通过降解为无机形式。(3)对27名矿工、冶炼厂和52名非汞作业工人进行了手部震颤和姿势摆动测试，以明确汞职业接触对神经运动的影响。尿汞均值接触组为2 2 8μg/gCre，非接触组为2.6μg/gCre。1~6赫兹和10~14赫兹的总震颤强度和特定频率震颤强度均显著大于非接触组，但与超高血糖无明显相关性。两组间各姿势摆动参数差异无统计学意义(P>0.05)，但经多元回归分析，暴露工人睁眼时的横向摆动与UHG呈正相关。这些发现表明，体位摆动和手部震颤可能受到元素汞蒸气暴露的影响。较少

The objectives of this research were to clarify the subclinical effects of environmental hazardous factors such as lead, cadmium, and methylmercury (MeHg), on nervous and renal functions in humans. (1) The first study was carried out to estimate the critical dose of lead affecting the neuromotor function in workers by introducing the benchmark dose (BMD) approach. Postural sway parameters with spectral analysis were compared between 121 lead workers with BPb levels of 6-89 μg/dl and 60 unexposed controls. All sway parameters, except for sagittal sways with eyes open, were significantly larger in the lead workers than in the controls. The critical dose of BPb was estimated to be 12.1-17.3 μg/dl for postural sway. (2) To investigate the relations among total mercury (THg) levels in hair, toenail, and urine, together with potential effects of MeHg intake on renal tubular function, their levels, and urinary N-acetyl-glucosaminidase activity (NAG) and α1-microglobulin (AMG) were determined … More in 59 women, and estimated daily mercury intakes from fish and other seafood using a food frequency questionnaire. THg levels in the women were 1.51±0.91 (SD) μg/g in hair, 0.59±0.32 μg/g in toenail, and 0.86±0.66 μg/g creatinine (Cre) in urine ; and, there were positive correlations among them. The daily mercury intake of 9.15±7.84 μg/day was significantly correlated with THg levels in hair, toenail, and urine. Among the women, the NAG and AMG were positively correlated with both the daily mercury intake and THg levels in hair, toenail, and urine ; and, these relations were almost similar when using multiple regression analysis to adjust for possible confounders such as urinary cadmium (0.47±0.28 μg/g Cre). In conclusion, MeHg resulting from fish consumption can explain total mercury levels in hair, toenail, and urine to some degree, partly through the degradation into the inorganic form. (3) To clarify the neuromotor effects of occupational exposure to mercury vapor, hand tremor and postural sway were measured in 27 miners and smelters and 52 unexposed subjects. The means of the urinary mercury level (UHg) were 228 μg/g Cre for the exposed workers and 2.6 μg/g Cre for the unexposed subjects. Total tremor intensity and frequency-specific tremor intensities at 1-6 and 10-14 Hz were significantly larger in the exposed workers than in the unexposed subjects, but they were not significantly related to the UHg among the exposed workers. In contrast, there were no significant differences in any postural sway parameters between the above two group, but the transversal sway with eyes open was positively related to the UHg among the exposed workers in using multiple regression analysis. These findings suggest that postural sway and hand tremor, may be affected by elemental mercury vapor exposure. Less