Ehp Niehs Nih Members 2005 8041

Ehp Niehs Nih Members 2005 8041

Neuro Development
with findings published in the October 2005 issue of EHP showingthat fish consumption during pregnancy appeared to boostinfant cognition-- But only as long as mercury intake, asmeasured in maternal hair, wasn’t too high.the question of whether low levels of mercury are harmfulhas also manifested itself in a controversy over the useof vaccines containing thimerosal, a preservative. Althoughthimerosal was removed from many of these vaccines in 2001,children that were immunized before that date could havereceived a cumulative dose of more than 200 ug/kgof mercury with the routine complement of childhood vaccinations,according to a study in the May 2001 issue of Pediatrics.Thimerosal is nearly half ethylmercury by weight. Becauseethylmercury is an organic form of mercury, there is somesuspicion that it acts like methylmercury in the brain,although research published in the August 2005 issue of EHP suggeststhat the two forms differ greatly in how they are distributedthrough and eliminated from the brain. Developing countriescontinue to use pediatric vaccines that contain thimerosal.In the United States, thimerosal is still present in influenzavaccines, which the CDC recommends be given to pregnantwomen and children aged 6-23 months.Advocacy groups, such as SafeMinds, have suggested thatthe decades- Long rise in the diagnosis of autism is relatedto the presence of thimerosal in vaccines. In May 2004,however, the Institute of Medicine (IOM) issued a report, ImmunizationSafety Review: Vaccines and Autism, stating that severalepidemiological studies published since 2001 consistentlyprovided evidence of no association between thimerosal- Containingvaccines and autism. However, the IOM’s report hasbeen severely criticized by a number of advocacy groups,including the National Autism Association, for relyingtoo heavily on a specific set of epidemiologic data whiledismissing clinical evidence and other epidemiologic studiesthat showed evidence of a link.Despite the assurances of the IOM, some scientists continueto explore the mechanisms underlying the potential neurotoxiceffects of thimerosal. In the January 2005 issue of NeuroToxicology,S. Jill James, a professor of pediatrics at the Universityof Arkansas for Medical Sciences, and her colleagues reportthat the neuronal and glial cell toxicity of methylmercuryand ethylmercury (as dosed via thimerosal) are both mediatedby the depletion of the antioxidant peptide glutathione.of the two cell types, neurons were found to be particularlysusceptible to ethylmercury-induced glutathione depletionand cell death, according to James, and pretreatment ofthe cells with glutathione reduced these effects. Otherstudies by James and her colleagues, reported in the December2004 issue of the American Journal of Clinical Nutrition,showed that autistic children had lower levels of glutathionecompared to normal controls, and may therefore have hada significant reduction in the ability to detoxify reactiveoxygen species.James says the abnormal profile suggests thatthese children may have an increased vulnerability to pro-oxidantenvironmental exposures and a lower threshold for oxidativeneurotoxicity and immunotoxicity. Speaking at theXXII International Neurotoxicology Conference in September2005, she presented evidence that multiple genetic polymorphismsaffecting glutathione pathways may interact to producea chronic metabolic imbalance that could contribute tothe development and clinical symptoms of autism. Her paperin the American Journal of Clinical Nutrition reportedthat low glutathione levels in many autistic children werereversible with targeted nutritional intervention, but

Ehp Niehs Nih Members 2005 8041

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Ehp Niehs Nih Members 2005 8041 8041 - Toxins - Find in Neurodevelopment and Health
Ehp Niehs Nih Members 2005 8041 8041 - Toxins in Neurodevelopment and Health

Ehp Niehs Nih Members 2005 8041 Neurodevelopment
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