Distribution of Mercury 203 in Pregnant Rats and Their Fetuses

Categories: Mercury Toxicity, ResearchAuthor: kkraterman

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To investigate the effect of amino acids and the tripeptide glutathione (GSH) on tissue uptake of methylmercury (MeHg) in the developing rat fetus in utero, pregnant rats were continuously infused into the external jugular vein with 0.1 mM L-cysteine, 0.1 mM L-leucine, 0.1 mM GSH or saline commencing on day 17 of gestation. This was followed at 24, 48, and 72 hours by external jugular infusion of 50 microM [203Hg]-MeHgCl administered in 1 ml over 1 hour. Pups were surgically removed from the uterus on gestational day 21. Whole body, brain, kidney, liver, and placental 203Hg radioactivity was measured by means of gamma-spectrometry. Brain 203Hg concentration in pups exposed in utero to L-cysteine was significantly higher compared with pups exposed to saline (P less than 0.05). Brain 203Hg concentration in pups exposed in utero to L-leucine and GSH was significantly depressed compared with pups exposed to saline (P less than 0.05). Kidney 203Hg concentration was not significantly changed in all treatment groups compared with controls. Liver 203Hg concentration was significantly depressed in L-leucine- and GSH-treated pups compared with controls (P less than 0.05). Placental 203Hg concentration was not affected by any treatment compared with controls. These effects occurred despite no difference in total 203Hg body burden among pups, irrespective of the treatment. In addition, infusion with L-cysteine resulted in a significant increase in 203Hg brain concentration in dams compared with controls, and 203Hg brain concentration in L-leucine- and GSH-treated dams was significantly depressed compared with controls. Thus 203Hg distribution in both adult and developing animals is altered by chronic amino acid or GSH infusions and suggests that MeHg uptake may be mediated through the formation of a cysteine-MeHg complex which is transported across the blood-brain barrier by the neutral amino acid carrier transport system.

Aschner M, Clarkson TW. Teratology. 1988 Aug; 38(2):145-55. 3175948 PubMed

Biliary Secretion of Glutathione and of Glutathione-Metal Complexes

Categories: Mercury Toxicity, News, ResearchAuthor: kkraterman

As bile is the main route of elimination of many metals, a large number of studies have been directed toward the characterization of the hepatobiliary transport of both endogenous and exogenous metals. Although some progress has been made, we still know little of the basic mechanisms involved in the hepatocellular uptake of metals, in their intracellular translocation and metabolism, or in their transport into bile. Our recent studies have focused on the last step in the hepatobiliary transport of mercury, namely, the secretion of the metal from liver cells into bile. The rate of secretion of methyl and inorganic mercury into bile was low in suckling rats and rapidly increased to adult rates soon after weaning. These changes closely followed similar developmental changes in the biliary secretion of reduced glutathione (GSH). When GSH secretion into bile was completely inhibited, without changing hepatic levels of GSH or mercury, mercury secretion was also completely blocked. Mercury secretion paralleled individual and sex-related differences in GSH secretion. At the same time, the secretion of mercury was independent of bile flow, of the thiol and mercury concentration gradients between bile and liver cells, and of those between bile and plasma. Our results, therefore, indicate a close coupling between the secretion of mercury and that of GSH. These in vivo findings, along with in vitro studies by others in vesicles isolated from the canalicular membrane of the liver cell, indicate a carrier-mediated transport system for GSH, but the nature of the linkage of this transport system with mercury secretion is not yet fully established. Our data and those in the literature are consistent with the involvement of at least two steps in the movement of mercury from liver cells to bile–the formation of a mercury-glutathione complex in the liver cell, followed by the secretion of this complex through a process closely linked to GSH secretion. The identification of GSH as an endogenous complexing agent in the transport of metals between tissues and body fluids now permits the design of therapeutic strategies aimed at exploiting this transport vehicle to effect the removal of metals via physiological routes of excretion. The present discussion considers the role of GSH in the hepatobiliary transport of metals. In doing so, a brief review is given of current understanding of hepatic GSH metabolism and transport.

Ballatori N, Clarkson TW. Fundam Appl Toxicol. 1985 Oct; 5(5):816-31. 4065458 PubMed.

California Keeps Warning Label on Amalgam

Categories: Hot Topics, Mercury Toxicity, NewsAuthor: admin

In November of 2010, the California Dental Board announced it would be reviewing the Watson Law fact sheet (a sheet of paper dentist are required to make available to patients that states warnings on various dental materials, including mercury amalgam fillings). The subcommittee reviewing the sheet consisted of two pro-mercury dentists. At that time, there was a real threat of the warning about amalgam being removed entirely from the sheet.

Today, Charlie Brown of National Counsel, Consumers for Dental Choice, announced that the mercury amalgam label will in fact REMAIN on the Watson Law fact sheet.

You can see his message in it’s entirety, below.

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California Dental Board Backs Down on Amalgam Fact Sheet

Dear California dentists, health professionals, and consumers,

The Dental Board of California has dropped a plan to weaken the warnings about amalgam required in the Watson Law fact sheet. The stark warnings in that fact sheet – which must go to every dental patient – will remain:

“Dental Amalgam: Mercury in its elemental form is on
the State of California’s Proposition 65 list of chemicals
known to the state to cause reproductive toxicity.
Mercury may harm the developing brain of a child or fetus.”

At its November 2010 meeting, the Dental Board announced that it would review the fact sheet and created a subcommittee of two pro-mercury dentists to propose changes. While the Board was content to let the California Dental Association call the shots, Consumers for Dental Choice was ready to make the mercury-free dentistry movement heard.

We began to organize the kind of coalition we had that led to the demise of the predecessor dental board (which, in violation of the Watson Law, had refused to produce any fact sheet at all). Consumer activist Anita Vazquez Tibau testified before the Board at its November 5 meeting, calling for a stronger – not a weaker – fact sheet, one that acknowledged the 2009 FDA rule’s warning that amalgam endangers the neurological systems of children and unborn babies. We followed up with strongly-worded letters. While the Board’s executive officer refused to answer, he got the message.

Last Friday, the Dental Board retreated, announcing it will not weaken the California fact sheet.

– Charlie

Charlie Brown
National Counsel, Consumers for Dental Choice

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What is the Watson Law Fact Sheet? This note comes from Wellsphere.com (http://www.wellsphere.com/healthy-living-article/california-dental-board-will-consider-revising-watson-law/1268278):

“LNH Note: The Watson Law, passed in 1992, requires the Dental Board to list the risks of mercury and other dental fillings. The previous Dental Board ducked its responsibilities under the Watson Law so blatantly, that the legislature shut the Board down. The Figueroa Amendment, passed in 2001, requires dentists to distribute a consumer-friendly fact sheet to patients. Have you ever received one from your dentist?”

http://www2.fluoridealert.org/Alert/United-States/California/Congresswoman-Diane-Watson-D-California-Introduces-Bill-to-Ban-Mercury-Amalgams

The World Alliance for Mercury-Free Dentistry Makes Progress at the Mercury Treaty Negotiations

Categories: Articles, Dr. Marvin's Blog, encinitas dentist, Hot Topics, Mercury Amalgam Fillings Research, Mercury Toxicity, News, ResearchAuthor: Dr. Marvin

Below is a recent email from World Alliance for Mercury-Free Dentistry, Charlie Brown and World Alliance for Mercury-Free Dentistry are making great strides and going to extreme lengths to help bring greater awareness to to mercury amalgam problem and the bring an end to it’s use in dentistry.

Please read the following article for information on their latest progress.

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Round two of the mercury treaty negotiations, held in Chiba Japan, was a success. Our umbrella coalition, the World Alliance for Mercury-Free Dentistry – “the voice of dental patients worldwide” – effectively countered the pro-mercury World Dental Federation (known under its French initials FDI), a lobby group funded by amalgam manufacturers. You can view photos from the negotiations online.*

We could not have done it without our sensational team – a depth of talent from five continents, including Dominique Bally of Cote d’Ivoire, Dr. Lillian Lasaten-Ebuen of the Philippines, Dr. Naji Kodeih of Lebanon, Dr. Graeme Munro-Hall of Great Britain, Juliet Pratt of New Zealand, Dr. Dave Simone of the United States, Anita Vazquez Tibau of the United States, and yours truly. Each spoke publicly on your behalf during the negotiations; each educated delegates at our booth and at meetings; each worked with United Nations Environmental Programme officials to develop strategies for stopping mercury fillings. We reached out to government officials from around the world, armed with diverse backgrounds ranging from injured consumers to dentists to environmentalists and multilingual talents spanning from Spanish to Tagalog to Arabic to Portuguese to French (not counting my fractured French, which is amusing to all except those who really speak French). And we achieved several major milestones:

Our meeting kicked off with the announcement that the World Health Organization has withdrawn the biased paper that the American Dental Association so heavily cited as “reinforc[ing] dental amalgam as a safe and effective restorative material.”** The alleged WHO report had been passed off as the conclusions of the team of scientists, environmentalists, and dentists who met in November 2009 to discuss the future of amalgam. We exposed the paper as nothing more than a propaganda piece slapped together by a rogue dentist inside WHO who failed even to consult the other meeting participants before signing their names to his paper (needless to say they were furious; they did not remember ever declaring amalgam safe). Then, we organized the worldwide condemnation of this paper that led to its hurried retraction. You can learn how we accomplished this feat step-by-step by watching this video interview, courtesy of filmmaker Kelly Gallagher.***

Because of our work, the first draft of the treaty lists amalgam as one of only five mercury products to be phased out. While the war is not won, we did succeed in keeping it on the list for now.

Thanks to the efforts of our regional vice presidents Dr. Naji Kodeih and Dominique Bally, both the Arab League and the African region announced that they support the phase-out of amalgam and the promotion of alternatives.

We gained a valuable new ally dedicated to ending dental mercury: Health Care Without Harm. We congratulate Health Care Without Harm for convincing the Mexico City Health Secretariat to deauthorize the purchase of amalgam in the city’s hospitals and obtaining a discussion paper from Argentina calling for a phase down of amalgam and use of alternatives.

The World Alliance for Mercury-Free Dentistry welcomes Dr. Lillian Lasaten-Ebuen as our new Vice President for East Asia. She joins Anita, Dominique, Juliet, Naji, and Marie Grosman of France as a regional leader at the treaty negotiations. Servando Perez of Spain remains our First Vice President, Elisabet Carlsson of Sweden is our senior advisor, and Francesca Romana Orlando of Italy is our director of development.
But the bottom line: The delegates made no major decisions in this early round, not on amalgam, not on anything. Thus how amalgam will ultimately be addressed in this treaty will not be determined until the third negotiating session, to be held in an African city in October. Until all the nations re-convene for negotiations, our World Alliance for Mercury-Free Dentistry will be active in each region of the world. I will provide details as they emerge.

– Charlie

Charles G. Brown
President, World Alliance for Mercury-Free Dentistry
National Counsel, Consumers for Dental Choice
15 February 2011

* links also available at http://toxicteeth.org/World-Mercury-Treaty-Gallery-2/

** link also available at http://www.ada.org/news/5082.aspx

*** link also available at http://www.youtube.com/watch?v=OGwHUSap5tg

ADA Does Support Mercury-Safe Dentistry

Categories: Mercury Amalgam Fillings Research, ResearchAuthor: admin

The ADA actually supports Mercury-Safe Dentistry, it just uses a different name. The ADA calls it The ADA’s ‘Dental Mercury Hygiene Recommendations’. The ADA lists a number of sources of mercury exposure at the dental office, including polishing and removing amalgam. It also recommends that all personnel involved in the handling of mercury and dental amalgam be trained in the potential hazards of mercury vapor and the necessity of observing good mercury hygiene. Although limited in scope, the ADA does promote mercury safe dentistry. So while it still may vehemently defend the use of amalgam, it encourages dentists to be mercury-safe. Not only does the ADA encourage dentists to be mercury-safe, it also shows that the ADA does not believe that the elemental mercury used in amalgams is somehow safer than elemental mercury used in other products and equipment.

The ADA’s Dental Mercury Hygiene Recommendations were published in: J AM Dent Assoc, Vol 134, No.11, 1498-1499; © 2003, American Dental Association. You can access the article online at http://jada.ada.org/cgi/content/full/134/11/1498.