08 Mar2011 0 Comments

Occupational Metal Exposures and the Risk of Parkinson’s Disease

Categories: ResearchAuthor: kkraterman

Occupational exposure to specific metals (manganese, copper, lead, iron, mercury, zinc, aluminum and others) appears to be a risk factor for Parkinson’s disease (PD) in some, but not all, case-control studies. These epidemiological studies are reviewed. Several methodological issues that may account for the lack of unanimity of findings are discussed, and suggestions for improved case-control methodology are offered. The study of the neurological disease outcome of workers who have had long-term, well-defined occupational exposure to one or more metals is also urged, with collaborative work including industrial hygienists, occupational toxicologists, neurologists, epidemiologists and biostatisticians. Such efforts, employing state-of-the-art case and control ascertainment and enrollment from suitable population bases, neurological diagnostic rigor and exposure assessment, will help to further define the potentially important roles played by metals in PD and other neurodegenerative disorders.

Gorell JM, Rybicki BA, Cole Johnson C, Peterson EL. Neuroepidemiology. 1999; 18(6):303-8. 10545782 PubMed.

08 Mar2011 0 Comments

Cysteine Metabolism and Metal Toxicity

Categories: Mercury Toxicity, ResearchAuthor: kkraterman

Chronic, low level exposure to toxic metals is an increasing global problem. The symptoms associated with the slow accumulation of toxic metals are multiple and rather nondescript, and overt expression of toxic effects may not appear until later in life. The sulfhydryl-reactive metals (mercury, cadmium, lead, arsenic) are particularly insidious and can affect a vast array of biochemical and nutritional processes. The primary mechanisms by which the sulfhydryl-reactive metals elicit their toxic effects are summarized. The pro-oxidative effects of the metals are compounded by the fact that the metals also inhibit antioxidative enzymes and deplete intracellular glutathione. The metals also have the potential to disrupt the metabolism and biological activities of many proteins due to their high affinity for free sulfhydryl groups. Cysteine has a pivotal role in inducible, endogenous detoxication mechanisms in the body, and metal exposure taxes cysteine status. The protective effects of glutathione and the metallothioneins are discussed in detail. Basic research pertaining to the transport of toxic metals into the brain is summarized, and a case is made for the use of hydrolyzed whey protein to support metal detoxification and neurological function. Metal exposure also affects essential element status, which can further decrease antioxidation and detoxification processes. Early detection and treatment of metal burden is important for successful detoxification, and optimization of nutritional status is paramount to the prevention and treatment of metal toxicity.

Quig D. Altern Med Rev. 1998 Aug; 3(4):262-70. 9727078 PubMed.

02 Mar2011 1 Comment

Possible Roles of Nitric Oxide and Redox Cell Signaling in Metal-Induced Toxicity and Carcinogenesis: A Review

Categories: Mercury Amalgam Fillings Research, Mercury Toxicity, ResearchAuthor: kkraterman

Toxic doses of transition metals are capable of disturbing the natural oxidation/reduction balance in cells through various mechanisms stemming from their own complex redox reactions with endogenous oxidants and effects on cellular antioxidant systems. The resulting oxidative stress may damage redox-sensitive signaling molecules, such as NO, S-nitrosothiols, AP-1, NF-kappaB, IkappaB, p53, p21ras, and others, and thus derange the cell signaling and gene expression systems. This, in turn, may produce a variety of toxic effects, including carcinogenesis. Experimental support for the relevance of oxidative damage to the mechanisms of metal toxicity and carcinogenicity is particularly strong for two essential (but toxic when overdosed) metals–iron and copper– and three well-established human metal carcinogens–nickel, chromium, and cadmium. However, along with more specific effects of toxic metals associated with their selective binding to particular cell constituents and affecting calcium signaling, oxidative damage seems to become important as well in explaining mechanisms of pathogenicity of other metals, such as lead, mercury, and arsenic.

Buzard GS, Kasprzak KS. J Environ Pathol Toxicol Oncol. 2000; 19(3):179-99. 10983886 PubMed.

02 Mar2011 0 Comments

Molecular Mechanisms of Metal Toxicity and Carcinogenesis

Categories: General Dentistry, Mercury Amalgam Fillings Research, Mercury Toxicity, ResearchAuthor: kkraterman

Many metals and metal-containing compounds have been identified to be potent mutagens and carcinogens. Recently, a new sub-discipline of molecular toxicology and carcinogenesis has been developed. The combination of newly developed molecular techniques and free radical approach makes it possible to insightfully examine metal-induced carcinogenesis in precise molecular terms so that intricate biological interrelationships can be elucidated. In consideration of the increased amount of new findings deciphered by utilizing these new methods, the 1st Conference on Molecular Mechanisms of Metal Toxicity and Carcinogenesis was held. In this conference, more than 50 scientists from nine countries presented their novel discoveries concerning metal-induced carcinogenesis, delineated molecular mechanism of metal carcinogenesis, and proposed novel therapeutic intervention and prevention strategies. This article reviews some of the state-of-the-art information presented at the meeting regarding the molecular mechanisms of metal cytotoxicity and carcinogenesis.

Wang S, Shi X. Mol Cell Biochem. 2001 Jun; 222(1-2):3-9. 11678608 PubMed.

01 Mar2011 0 Comments

Metal Exposure from Amalgam Alters the Distribution of Trace Elements in Blood Cells and Plasma

Categories: Mercury Amalgam Fillings Research, Mercury Toxicity, ResearchAuthor: kkraterman

Twenty-seven consecutive patients with health problems associated with dental amalgam were recruited. In spite of thorough medical examinations, there were no diagnoses available. The patient group was dominated by women. A healthy age- and sex-matched control group with dental amalgams without symptoms was also recruited. Metal level monitoring in plasma and nuclear microscopy of isolated individual blood cells were carried out. Significant increases of copper, iron, zinc and strontium were found in patient plasma. There was no significant difference in plasma selenium between the groups. Mercury was significantly increased in patient plasma, although there was overlap between the groups. In erythrocytes a significant increase in calcium and a significant decrease in magnesium, copper, manganese and zinc were found. Calcium, magnesium, manganese and copper increased in patient neutrophil granulocytes. A significant decrease was found for zinc. A conspicuous finding was the presence of measurable mercury in a few of the cells from the patient but not in the control group.

Lindh U, Carlmark B, Gronquist SO, Lindvall A. Clin Chem Lab Med. 2001 Feb; 39(2):134-42. 11341747 PubMed.

Articles

Tag Archive for: metal

Occupational Metal Exposures and the Risk of Parkinson’s Disease

Cysteine Metabolism and Metal Toxicity

Possible Roles of Nitric Oxide and Redox Cell Signaling in Metal-Induced Toxicity and Carcinogenesis: A Review

Molecular Mechanisms of Metal Toxicity and Carcinogenesis

Metal Exposure from Amalgam Alters the Distribution of Trace Elements in Blood Cells and Plasma

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