Brodkin, E., Copes, R., Mattman, A., Kennedy, J., Kling, R., & Yassi, A. (2007, January 2). Lead and mercury exposures: interpretation and action.. CMAJ: Canadian Medical Association Journal Supplement, 176(1), 59-63. Retrieved August 10, 2009, doi:10.1503/cmaj.060790
So autism looks like this how?
"Signs and symptoms of mercury toxicity vary with the form of mercury and route of exposure but include gingivitis, stomatitis and excessive salivation. Sensory peripheral neuropathy is
common, and central nervous system effects include personality changes, irritability, fatigue, tremor (usually intention tremor), ataxia, difficulties with memory and concentration, sleep disturbances and a metallic taste. Renal effects include both tubular and glomerular damage. In the fetus, organic mercury disrupts the cytoarchitecture of the developing brain and has been associated with neuropsychological changes after birth" (Brodkin et al., 61).
Oh, I bet folks who think it's mercury poisoning will point to the last, except they aren't arguing it was fetal poisoning. They are arguing it's the 12.5 to 25 micrograms of thimerosal in certain vaccines that did, forget about the 11.5 or so micrograms of mercury in a can of tuna. My bad. Then, they'll point out absorption and excretion is completely different.
What about chelation?
"The first step in treating all cases of heavy metal toxicity is to reduce or remove the source of exposure. In most cases this is all that is required.3,16 Chelation therapy has historically been used to reduce the body burden of heavy metals in patients with se-vere symptoms and highly elevated circulating levels of heavy metals.26 It is a process in which heavy metals are removed
from the body with the use of a chelating agent, a charged molecule that binds metals in a stable complex known as a chelate. The chelate is subsequently excreted in the urine" (Brodkin et al., 61-62).
"Chelation therapy should be carried out only in a hospital setting by experienced physicians" (Brodkin et al., 62).
What about chelating and then doing a urine test?
"This procedure is more commonly known as the chelation challenge test or
provocation chelation. It entails measuring urine levels of heavy metals before and after a single loading dose of a known chelating agent. It has been used to determine whether chelation therapy is indicated but is also used by some alternative health care providers to diagnose heavy
metal poisoning. There is no good evidence supporting the use of the chelation challenge test for either purpose, and findings from some studies have suggested that it can lead to misleading diagnostic advice" (Brodkin et al., 62).
Okay, so most parents of kids with autism who think it is heavy metal toxicity don't IV chelate. Gotcha.
So what about oral chelating agents DMPS and DMPA?
Here's a study showing them ineffective in removing elemental mercury after a person intentionally injected himself with elemental mercury in a suicide attempt.
Eyer, F., Felgenhauer, N., Pfab, R., Drasch, G., & Zilker, T. (2006, July). Neither DMPS nor DMSA is Effective in Quantitative Elimination of Elemental Mercury After Intentional IV Injection.. Clinical Toxicology (15563650), 44(4), 395-397. Retrieved August 10, 2009, doi:10.1080/15563650600671795
"Although treatment with DMPS or DMSA was associated with marginally increased renal excretion of Hg in our patient, clinically relevant elimination did not occur and evidence of
benefit is doubtful" (Eyer et al., 397).
So, I'll have to do some more digging, but for now it appears that the oral chelating agents DMPS and DMSA are ineffective, at least when mercury is injected.
In case you think oral chelators are no big deal:
"Chelation agents like DMPS or DMSA are increasingly used and are available over the counter in some countries. These drugs are used in patients with complaints that are attributed to mercury-containing dental amalgams and in children with autism. Conclusion. The reported association suggests that SJS may be a potential complication of DMPS therapy, and this should be considered in the risk-benefit analysis of chelation. The reported association suggests that SJS may be a potential complication of DMPS therapy, and this should be considered in the risk-benefit analysis of chelation."
AA, V., S, P., GP, G., & JN, B. (2008, June). Stevens-Johnson syndrome in a child with chronic mercury exposure and 2,3-dimercaptopropane-1-sulfonate (DMPS) therapy. Clinical Toxicology (Philadelphia, Pa.), 46(5), 479-481. Retrieved August 10, 2009, from MEDLINE database.
Trying to make this not look like a study dump like some folks do at some places. :-)
The 14 study argument is hogwash. There. In case I hadn't made that plain enough in my other posts. I've said it clearly. Complete and utter balderdash. I've used the IOM review in previous postings. Here's a quote from an article in Nature Neuroscience referring to it as well:
"Unfortunately, epidemiological studies do not support this link. In May 2004, a review by the Institute of Medicine (IOM)3 of over 200 studies (available online at http://www.nap.edu/catalog/10997.html) concluded “that the evidence favors rejection of a causal relationship between thimerosalcontaining vaccines and autism,” a view held by most of the international scientific community. The World Health Organization also maintains that
“there is no evidence supporting a causal association between neurobehavioural disorders and thiomersal-containing vaccines.”"
Reference: A mercurial debate over autism. (2005, September). Nature Neuroscience, Retrieved August 10, 2009, from MEDLINE database.