Re: Thimerosal distribution and metabolism in neonatal mice: comparison with met

[Guest guest]

Thanks Donna for posting this. To summarise for the group, what the

researchers found was a clear association between thimerosal and

increasing levels over time of inorganic mercury in the brain

corresponding with decreasing organic mercury. As Andy has been

correctly stating for years, the organic mercury that makes its way

into brain converts to the inorganic form. It is this form of mercury

that does not freely cross the BBB and so becomes essentially

" trapped " unless appropriately chelated with lipoic acid. Yet more

mainstream research corroborating Andy's work.

Regards,

Austin

>

> Department of Environmental Medicine, University of Rochester, School

> of Medicine and Dentistry, Rochester, NY, USA.

>

> Thimerosal, which releases the ethyl mercury radical as the active

> species, has been used as a preservative in many currently marketed

> vaccines throughout the world. Because of concerns that its toxicity

> could be similar to that of methyl mercury, it is no longer

> incorporated in many vaccines in the United States. There are reasons

> to believe, however, that the disposition and toxicity of ethyl

> mercury compounds, including thimerosal, may differ substantially

> from those of the methyl form. The current study sought to compare,

> in neonatal mice, the tissue concentrations, disposition and

> metabolism of thimerosal with that of methyl mercury. ICR mice were

> given single intramuscular injections of thimerosal or methyl mercury

> (1.4 mg Hg kg(-1)) on postnatal day 10 (PND 10). Tissue samples were

> collected daily on PND 11-14. Most analysed tissues demonstrated

> different patterns of tissue distribution and a different rate of

> mercury decomposition. The mean organic mercury in the brain and

> kidneys was significantly lower in mice treated with thimerosal than

> in the methyl mercury-treated group. In the brain, thimerosal-exposed

> mice showed a steady decrease of organic mercury levels following the

> initial peak, whereas in the methyl mercury-exposed mice,

> concentrations peaked on day 2 after exposure. In the kidneys,

> thimerosal-exposed mice retained significantly higher inorganic

> mercury levels than methyl mercury-treated mice. In the liver both

> organic and inorganic mercury concentrations were significantly

> higher in thimerosal-exposed mice than in the methyl mercury group.

> Ethyl mercury was incorporated into growing hair in a similar manner

> to methyl mercury. The data showing significant kinetic differences

> in tissue distribution and metabolism of mercury species challenge

> the assumption that ethyl mercury is toxicologically identical to

> methyl mercury. Copyright © 2007 Wiley & Sons, Ltd.

>

> PMID: 17582588 [PubMed - as supplied by publisher]

>

>

> http://www.ncbi.nlm.nih.gov/sites/entrez?

> Db=pubmed & Cmd=ShowDetailView & TermToSearch=17582588 & ordinalpos=1 & itool=

> EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum

>