关于药物排铅的研究

问号

NIH资助的针对老鼠的药物排铅研究
螯合剂是DMSA

“能够明显地减轻学习和行为方面的问题”

但是

"如果老鼠并没有铅中毒，却要使用螯合剂排铅，结果会在学习和行为方面的问题产生于类似铅中毒的症状"

也就是说，如果孩子没有铅中毒，还是要螯合治疗，会起到反作用。

Lead chelation therapy -- a chemical treatment to remove lead from the body -- can significantly reduce learning and behavioral problems that result from lead exposure, a Cornell study of young rats finds.

However, in a further finding that has implications for the treatment of autistic children, the researchers say that when rats with no lead in their systems were treated with the lead-removing chemical, they showed declines in their learning and behavior that were similar to the rats that were exposed to lead.

Chelating drugs, which bind to lead and other metals in the blood, are increasingly being used for the treatment of autism in children.

"Although these drugs are widely used to treat lead-exposed children, there is remarkably little research on whether or not they improve cognitive outcomes, the major area of concern in relation to childhood lead poisoning," said Barbara Strupp, Cornell associate professor of nutritional sciences and of psychology and the senior author of the study, which was published in a recent issue of Environmental Health Perspectives.

Studies on the safety or effectiveness of the drugs for treating autism are similarly lacking, Strupp said.

Strupp added that to her knowledge this is the first report that shows that chelation therapy can reduce behavioral and learning problems due to lead exposure as well as the first to show that this type of treatment can have lasting adverse effects when administered in the absence of elevated levels of heavy metals.

The study used succimer (brand name, Chemet), the most widely prescribed drug for the treatment of lead poisoning. Doctors prefer succimer to other such drugs because it can be given orally on an outpatient basis, and it leaches less zinc, iron and other essential minerals out of the body. Although the Centers for Disease Control recommends chelation therapy only for children whose blood lead levels exceed 45 micrograms per deciliter, such drugs as succimer are commonly administered at much lower levels of exposure, due to concerns about lasting complications with even slightly elevated blood lead levels.

It is important to remove lead from the body as quickly as possible to prevent or lessen lasting damage to the developing brain. High-lead exposure from peeling lead-based paint can lead to coma, convulsions and even death. At lower levels, lead exposure causes attention deficits, delinquency and difficulty regulating emotions and can lower IQ scores at a rate of about one IQ point per microgram/deciliter of exposure.

The study used rats -- whose mental and behavioral responses to lead exposure are similar to humans' -- and exposed them to moderate- and high-lead levels (administered via mothers' milk). A third group -- the control -- was not exposed. Exposures were followed by a treatment with succimer or placebo. Immediately thereafter, the researchers conducted automated tests over six months on the rats' attention, memory and abilities to learn and regulate emotions.

The rats with moderate-lead exposure benefited greatly from the succimer: Their test results were indistinguishable from the control test results. Rats exposed to higher lead levels showed benefits in the emotional domain: After succimer treatment, they behaved similarly to the control group. However, the treatment only slightly improved their learning deficit.

In the group that had no lead exposure but were given succimer, "we found lasting cognition and emotion-regulation [deficits] that were as pervasive and large as rats with high lead exposure," said Strupp. She added that one possibility is that succimer, in the absence of lead, may disrupt the balance of such essential minerals as zinc and iron. "These findings raise concerns about the use of chelating agents in treating autistic children," she said.

一生平安

请问 问号 我儿子正在排铅中,本来中毒不很深,好象就是刚刚达到轻度的低值,安全值超一点.医生说这种情况应该排,加之儿子的一些累似中毒的行为问题,我就选择了排.用的是智桤颗粒用了半个多月吧.看了您的帖子,我有点醒悟了,因为他爸昨天就说这孩子近来怎么这么难管呢,老犟嘴,反正比以前难管,脾气更急,我们还以为是排铅的同时排走了一些微量元素,现在看来是副作用?请您给我点建议吧.谢谢了

thankstoyilin

目前医学认为，血铅含量略超安全值的情况下，不需要药物排毒。在排除环境中可能的污染源（比如某些工厂）、给孩子养成良好卫生习惯、注意合理饮食等几个方面来改善。药物排毒是要非常谨慎的。

之前，我整理过一个关于血铅的小综述。

一生平安

  

致thankstoyilin  ；　



谢谢您的提醒．但听说排铅是讲疗程的，否则铅会积聚在血液里．｛本来在骨头里｝我现在真不知该不该立即停止排铅．您有这方面的经验吗？

thankstoyilin

你先看我的这个帖子，以及其他网友的跟贴：http://www.elimautism.org/leadbbs/Announce/Announce.asp?BoardID=12&ID=176963

任何药物排铅都要非常慎重，如果孩子的静脉血测得的血铅水平略高于100ug/L，医学建议还是营养干预和日常习惯改善，不需要去采取药物治疗。

另外，血铅测定如果不正规的话，可能有误差。指尖采血相比于抽取静脉血，误差也大一些，容易偏高。（说明，关于最后一点，我是听朋友说起，也请相关专业的家长指正。我个人认为，之间采血可能容易引入污染。）

pengxc

对排铅药物的研究结果，我有质疑。首先，老鼠与人有巨大差异，通常老鼠的试验结果不能直截推演于人。而且凭一篇文章，没有别人研究来证实，可信度很有限。最重要的是，排铅药物已有于人体达半个世纪之久，根本没有听说过这方面的付作用报道。小心没错，但不要过度反应。