铝神经毒性的线粒体机制

探讨铝致神经毒性的机制.铝具有神经毒性,其毒性作用的确切机制目前尚不清楚.本文综述了国内外关于铝致神经毒性的作用机制研究,提出了新的研究设想并阐述其研究意义.     

铝的生物学作用研究概况

除茶叶等某些天然食品中铝含量较高外 ,大多数主要食品中铝含量较低 ,一般不超过 10mg kg。而在加有含铝添加剂的食品中铝含量较高。经含铝混凝剂处理后的饮用水铝浓度升高。我国居民从铝制炊具摄入的铝为 4mg (capit·d)。成人一般摄铝量在 10mg (capit·d)左右 ,而摄入高铝性食品或含铝药品摄铝量可增至每人每天数十至数百毫克。铝主要在十二指肠吸收 ,主要经肾排出。铝的蓄积与中枢神经系统损害、骨损害和造血系统损害有关 ,尤其与阿尔茨海默氏病关系密切。本文就铝在食品中的含量、铝在体内代谢、铝的生物毒性及其某些未解决的问题等进行综述     

茶中铝元素的安全性评估

铝是人体非必需矿物质 ,已发现铝元素摄取过多与多种疾病相关联。茶是少数几种可在体内蓄积铝元素的植物之一 ,而有将近世界人口一半的人有饮茶习惯 ,因此近年来茶中铝问题引起关注。就近年来有关茶树中铝分布和铝浓度、茶叶和茶汤铝浓度、动物实验、人体实验、流行病学调查几个方面的研究文献 ,对茶中铝的安全性进行系统详细地综述。结论为茶中铝元素对人体健康可能有负面影响。     

铝的毒性作用研究进展

目的 了解铝对人体各系统的影响,为控制其毒性作用提供一定参考依据。方法 检索PubMed数据库,纵览国外关于铝暴露致体内、体外危害及相关机制的文献,进一步选择如亚慢性铝暴露60天对小鼠唾液腺的影响等文献,提炼其相关结果结论进行综述。结果 铝摄入剂量和暴露时间可能对各系统有消极作用,对神经系统的作用尤为明显。结论 铝对人体各系统均有毒性作用,可能是各系统相关疾病发生因素之一,尤其是导致阿尔兹海默病等神经退行性疾病发生的重要原因之一。     

Aluminum exposure from pediatric parenteral nutrition: meeting the new FDA regulation

BACKGROUND: Aluminum toxicity can cause serious central nervous system and bone toxicities. Aluminum is a contaminant of parenteral nutrition (PN) solution components. Premature neonates requiring high doses of calcium and phosphate to mineralize their bones, children with impaired renal function, and children on PN therapy for prolonged duration are at the highest risk. Effective in July 2004, the U.S. Food and Drug Administration (FDA) mandated labeling requirements for aluminum content in all PN solution components. To assess the aluminum exposure in neonatal and pediatric populations, this study aims to determine patients' daily aluminum load (mug/kg/d) delivered from PN solutions. METHODS: The study included all inpatients who received PN during calendar year 2006 (13,384 PN patient days). The calculated parameters of mug/kg/d and mug/L of parentally administered aluminum were stratified according to patient age and weight. Aluminum content by product and manufacturer were tabulated. RESULTS: Forty-nine percent of the PN patient days were in patients weighing < 3 kg. These patients also received the largest amounts of aluminum (range, 30-60 mug/kg/d). Meeting the FDA regulation was possible only in patients weighing > 50 kg. CONCLUSIONS: Currently available parenteral products used to make PN solutions contain amounts of aluminum that make it impossible to meet the new FDA rule of <5 mug/kg/d of aluminum exposure. Manufacturers must identify, develop, and adopt new methods to reduce the aluminum contamination in their products. Health care professionals should calculate aluminum loads in patients and make informed decisions when choosing PN products.     

谷氨酸钠对铝在组织中沉积和体内抗氧化能力的影响研究

目的 :　了解谷氨酸钠对铝在组织中沉积及其对体内抗氧化能力的影响。方法 :　采用 2 4只 SD大鼠 ,体重约 ( 1 2 5± 1 5 ) g,平均分成 4组 ,进行为期 5 0 d的灌服试验 ,分别灌服蒸馏水 (空白对照组 ) ,1 .2 mmol氯化铝 ,1 .2 mmol柠檬酸钠 + 1 .2 mmol氯化铝 ,1 .2 mmol谷氨酸钠+ 1 .2 mmol氯化铝。取脑、肝、肾、骨组织及血液 ,测定组织中铝的含量 ,并测定血浆 MDA量和SOD活力。结果 :　给试验鼠服用铝 ,都能提高铝的吸收量 ,使各组织中铝的含量升高。同时给予铝和柠檬酸盐时 ,试验鼠肾、骨中铝的含量极显著地高于对照组和 Al Cl3 组 ( P<0 .0 1 ) ,肝中铝含量极显著地高于对照组 ( P<0 .0 1 ) ,脑中铝含量也显著高于对照组 ( P<0 .0 5 )。同时给予铝和谷氨酸钠 ,试验鼠肾、脑中铝的含量极显著地高于对照组和 Al Cl3 组 ( P<0 .0 1 ) ,血红细胞中铝的含量显著地高于对照组 ( P<0 .0 5 )。试验鼠同时服用铝和柠檬酸钠或谷氨酸钠将减弱血浆的抗氧化能力 ,血浆中 MDA的量明显增加 ,SOD酶活力则显著降低 ( P<0 .0 1 )。结论 :　谷氨酸钠和柠檬酸钠均能促进铝在组织中的沉积 ,减弱血浆的抗氧化能力。谷氨酸钠很可能是其α- NH2 ,α- CH-及 - COO-与Al形成络合物的结果。     

金华市区油条铝含量检测结果分析

目的：通过对市区105家油条加工经营户油条铝含量测定,了解油条铝残留量超标情况。方法：对抽检123份样本按国家标准GB15202-94《面制品中铝限量卫生标准》中的检验方法监测。结果：123份样本铝残留量281～823mg/kg,平均522.21±141.31mg/kg,平均超限5.22倍,合格率4.8%。结论：油条铝残量超标严重高达95.2%,应研制无铝油条配方替代传统配方,消除安全隐患。     

The biological speciation and toxicokinetics of aluminum.

This review discusses recent literature on the chemical and physiological factors that influence the absorption, distribution, and excretion of aluminum in mammals, with particular regard to gastrointestinal absorption and speciation in plasma. Humans encounter aluminum, a ubiquitous yet highly insoluble element in most forms, in foods, drinking water, and pharmaceuticals. Exposure also occurs by inhalation of dust and aerosols, particularly in occupational settings. Absorption from the gut depends largely on pH and the presence of complexing ligands, particularly carboxylic acids, with which the metal can form absorbable neutral aluminum species. Uremic animals and humans experience higher than normal body burdens of aluminum despite increased urinary clearance of the metal. In plasma, 80-90% of aluminum binds to transferrin, an iron-transport protein for which receptors exist in many tissue. The remaining fraction of plasma aluminum takes the form of small-molecule hydroxy species and small complexes with carboxylic acids, phosphate, and, to a much lesser degree, amino acids. Most of these species have not been observed in vivo but are predicted from equilibrium models derived from potentiometric methods and NMR investigations. These models predict that the major small-molecule aluminum species under plasma conditions are charged and hence unavailable for uptake into tissues.     

膳食铝暴露评估及食品中铝限量安全标准研究进展

随着工业和建筑行业的高速发展,工业废水,酸雨等污染环境,以及含铝食品添加剂的滥用和铝包装材料的广泛使用,铝在食品中的含量达到较高水平.人群通过空气,饮水,食品等途径摄入铝,造成人体内的平均铝含量已严重超标,膳食铝暴露是主要原因.对居民膳食铝暴露评估结果表明,居民通过面制食品摄入的铝量较高,这与使用铝制器具及在食品中添加含铝添加剂有关.本文将对膳食铝暴露评估及食品中铝限量安全标准研究进展进行综述,为相关部门修订食品中铝安全标准提供参考.     

饮用水中铝的来源危害与防治

铝是重要的金属元素,它的广泛应用引起了饮用水的污染,导致了饮用水中铝含量的不断升高,直接或间接地危害到人体的身心健康,威胁着人类的生存与发展。介绍了饮用水中铝的来源、危害及其防治措施,并提出保护环境,适度地开发和利用铝资源是防治铝危害的重要策略。     

Occupational burns from oxygen resuscitator fires: the hazard of aluminum regulators

BACKGROUND: There have been over 30 incidents of oxygen resuscitator fires over the last 6 years, causing severe burns to a number of fire fighters, emergency medical service personnel, health care workers, and patients. The National Institute for Occupational Safety and Health (NIOSH) was requested to investigate three such incidents. METHODS: NIOSH conducted site investigations of the incidents, and the requesters also sent the involved oxygen resuscitators to a forensic engineering company for a causal analysis. RESULTS: The investigated fires were associated with aluminum regulators, all from one manufacturer, on compressed pure oxygen cylinders. The investigations indicated that the cause of the fires was an initial small ignition in the high-pressure area of the aluminum regulator, which then consumed itself in a massive burnout. CONCLUSIONS: Aluminum regulators used with high-pressure oxygen systems are subject to rare, but potentially catastrophic combustion in normal use. Replacement of such regulators with those made of more fire-resistant materials or designs, as well as education and improved safety practices are needed to reduce this hazard.     

Neuropsychological function among workers exposed to aluminum – a mini-review

Aluminum (Al) is the most common element in nature after oxygen and silicon. Aluminum has been proposed to be a causative agent in the development of neurodegenerative diseases. Aluminum made available via the lungs, as it is in occupational settings, is probably better absorbed than that entering the body via the gastrointestinal tract. Neuropsychological tests are sensitive methods for detecting subtle functional impairment of the nervous system. This minireview is based on a systematic literature search for studies on workers occupationally exposed to aluminum. The tests were categorized as belonging to one of 12 different neuropsychological functions. The level of significance was set at p<0.05. Among the 559 papers identified, 24 fulfilled the inclusion criteria. There were no clear, consistent findings of occupational aluminum exposure being correlated with neuropsychological deficits. However, there was a weak tendency toward worse performances on tests related to information processing speed and a slight tendency toward weaker performances on memory tests for workers exposed to aluminum. The limited number of studies in this field makes it difficult to draw a clear conclusion regarding whether occupational exposure to aluminum increases the risk of altered neuropsychological function.     

Parenteral nutrition-associated cholestasis in neonates: the role of aluminum

Parenteral nutrition (PN) is an essential component in the care of premature and ill infants. The incidence of parenteral nutrition-associated cholestasis (PNAC) ranges from 7.4 to 84%. One substance in PN solutions that has been implicated in PNAC is aluminum. Aluminum loading in animals and humans causes hepatic accumulation and damage. The degree of aluminum contamination of PN solutions has decreased over time, but contamination still significantly exceeds levels that are safe for human neonates. Further study into the relationship between aluminum contamination in neonatal PN solutions and the development of PNAC is necessary.     

谷氨酸钠对铝在体外吸收的影响

目的　了解谷氨酸钠对铝吸收的影响。方法　 1 8只 SD雄性大鼠 ,体重 (2 50±1 5) g,被翻转的离体十二指肠、空肠、回肠 ,在其内腔充满 p H 7.3的缓冲液 (其组成为 Tris- HCl1 5.5mmol,Na Cl1 2 0 .7mmol,KCl5.6mmol,Ca Cl2 2 .5mmol,Mg Cl2 1 .2 mmol,glucose1 1 .5mmol)后 ,置于 p H7.3含待测液的生理盐水中 ,待测物分别为 2 0 mmol Al Cl3,2 0 mmol Al Cl3+2 0mmol柠蒙酸钠和 2 0 mmol Al Cl3+2 0 mmol谷氨酸钠。恒温 (37± 0 .1 )℃培养 0 .5h,培养期间通入95% O2 和 5% CO2 气体。然后用石墨炉无火焰原子吸收分光光度计 ,分别测定肠内腔液和肠的铝含量。结果　对照组 (Al Cl3)十二指肠、空肠、回肠对铝的吸收率 (鲜肠重计 )分别为 3.59± 0 .55,3.41± 0 .61和 3.1 9± 0 .68(μg/g) ,参照组 (Al+柠檬酸钠 )分别为 4.92± 0 .73,4.47± 0 .56和4.37± 0 .77(μg/g) ,试验组 (Al+谷氨酸钠 )分别为 4.75± 0 .68,4.45± 0 .59和 4.32± 0 .63(μg/g) ,参照组与试验组的十二指肠、空肠、回肠铝吸收率与对照组相比有显著差异。如将肠段重换算成干重 ,则参照组和试验组仅十二指肠铝的吸收率与对照组相比有显著差异 (其吸收率为 :2 7.51±1 .88和 2 8.67± 2 .1 6对 2 4 .98± 1 .75(μg/g) ,而空肠、回?     

儿童铝负荷状况及铝神经毒作用机制的研究进展

铝是一种慢性蓄积性环境神经毒物。随着人体铝接触途径的多样化和不可避免性,其铝负荷水平呈上升趋势,长期铝负荷导致的神经生物毒性受到广泛关注。对于生长发育迅速的儿童来说,铝摄入量、铝吸收率以及体内铝负荷水平往往高于普通成人。长期持续低剂量铝负荷可能给儿童神经发育功能造成各种慢性亚临床损害及远期不可逆危害。鉴于以上背景,本文主要从儿童铝负荷状况、铝负荷对其神经发育功能的影响及神经发育功能受损相关机制的研究进展等方面进行阐述,为预防或治疗儿童铝负荷引起的健康问题提供理论依据,同时为儿童预防保健工作提供发展思路。     

重金属暴露与心血管疾病关系的流行病学研究进展

重金属是重要环境污染物之一,其对心血管系统的损害已备受国内外学者的关注。本文基于重金属人体负荷水平、重金属暴露对心血管系统危害的相关研究成果,综述铅、镉、砷3种常见重金属暴露与心血管疾病关系的流行病学研究进展,并提出应加强全国范围一般人群重金属负荷水平的监测,以利于定量评估重金属暴露所致的心血管疾病风险。     

孕哺期铝暴露对仔鼠海马LTP及Glu含量影响

目的 研究孕哺期染铝对仔鼠长时程增强(LTP)和谷氨酸(Glu)含量影响,探讨铝对发育中中枢神经系统毒性作用及机制.方法 Wistar大鼠怀孕起染AlCl3至仔鼠哺乳期结束,共计6周,原子吸收石墨炉法测定血铝和脑铝含量;细胞外微电极技术测定LTP;免疫组化法测定海马谷氨酸含量.结果 0.2％ AlCl3组仔鼠血铝和脑铝分别为(47.43±14.38)mg/L、(13.86±6.60)mg/g;0.4％ AlCl3组血铝和脑铝为(55.56±19.07) mg/L、(18.79±5.18)mg/g,与对照组[(33.89±8.74) mg/L,(7.61±3.44) mg/g]比较,血铝、脑铝含量均明显增加(P ＜0.05);CAl区LTP的诱导和维持明显受到抑制,其群体峰电位幅值增强率明显低于对照组(P＜0.01).孕哺期铝暴露使仔鼠海马内谷氨酸含量下降(P＜0.05).CAl区对照组,0.2％ AlCl3组和0.4％ AlCl3组谷氨酸平均吸光度(A)值分别为(0.35±0.02)、(0.33 +0.02)、(0.29±0.03),阳性面积比分别为(5.06±1.36)、(4.70±0.56)、(1.71 +0.23).结论 孕哺期铝暴露可以使仔鼠海马CA1区LTP的诱导和维持受到抑制,谷氨酸水平下降.     

桂西铝工业基地居民血清微量元素含量及其与糖代谢异常关系研究

[目的]探讨桂西铝工业基地居民人群血清微量元素铝元素(Al)、铅元素(Pb)、铬元素(Cr)含量及空腹血糖水平,分析其对葡萄糖代谢的影响。[方法]分别检测106例桂西铝工业基地居民与87例健康成人血清铝元素(Al)、铅元素(Pb)、铬元素(Cr)及空腹血糖水平,分布通过t检验比较两组间平均水平差异(P=0.05),χ2检验比较两组间糖代谢异常率的差异(P=0.05),最后通过非条件多因素Logistic回归模型分析微量元素在糖代谢异常中的作用。数据统计分析均经SPSS17.0统计软件系统进行。[结果]与北部湾居民组相比较,桂西铝工业基地居民血清铝元素(Al)、铅元素(Pb)、铬元素(Cr)及空腹血糖水平差异有统计学意义(P﹤0.05),糖代谢异常率9.4%(10/106)显著升高(P﹤0.05)。非条件Logistic回归模型分析提示Al[β=2.530,P=0.001,OR=3.681,95%CI(1.985,11.268)],Pb[β=1.938,P=0.011,OR=2.129,95%CI(1.348,7.235)],Cr[β=-0653,P=0.023,OR=0.621,95%CI(0.256,0.956)]差异均有统计学意义。[结论]桂西铝工业基地居民血清铝元素(Al)、铅元素(Pb)水平升高,铬元素(Cr)水平下降,可能导致糖代谢异常高发,其中铝元素(Al)、铅元素(Pb)水平过高可能为糖代谢异常的危险因素,铬元素(Cr)可能为保护性因素。     

Influence of oligomeric silicic and humic acids on aluminum accumulation in a freshwater grazing invertebrate

This study examined the influence of oligomeric silicic acid and humic acid on aluminum in the water column and its accumulation in the freshwater snail Lymnaea stagnalis. Forty-eight hours after addition of Al (500 microg L(-1)), 83% of the metal was lost from the water column. This loss was reduced by oligomeric silica (20 mg L(-1)) and by humic acid (10 mg L(-1)). Aluminum accumulated in the digestive gland and, to a lesser extent, in the remaining soft tissues, and this accumulation was reduced by oligomeric silica. In the presence of humic acid, Al accumulation in the digestive gland was unaffected, though less was accumulated in the remaining tissues. Snails accumulated Si preferentially in the digestive gland and this accumulation was increased in the presence of added Al. Thus, both oligomeric silica and humic acid influence Al bioavailability and Si is upregulated in the digestive gland in the presence of Al.     

Interaction of aluminum with exogenous and endogenous iron in the organism of rats

The aim of these experiments was to find changes in free erythrocyte protoporphyrins (FEP) and in the concentration of endogenous iron in the blood, erythrocytes, serum, liver, kidneys, and spleen of rats, as well as in the dynamics of aluminum concentrations in the serum of rats after oral application of aluminum chloride (AlCl(3)) separately or with ferrum chloride (FeCl(2)), depending on the time and doses administered. The experiments were carried out on female Wistar rats which received (p.o.) 100 mg Al/kg separately or with iron (4 mg Fe/kg) daily for 35 days. The effects of aluminum administration were noticed after the second week. The experiments demonstrated that the increase in the level of free erythrocyte protoporphyrins in the blood is the most sensitive indicator of exposure to AlCl(3). A decrease in iron concentration in erythrocytes, blood, and spleen was also noticed. The response and the sequence of the investigated effects were recorded according to aluminum and iron concentration in the serum. Joint administration of iron and aluminum decreases concentration of aluminum in serum and prevents changes in the investigated indicators in rats exposed to aluminum chloride.