Arsenic is a chemical element with the symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, but only the gray form, which has a metallic appearance, is important to industry.
A toxic heavy metal is any relatively dense metal or metalloid that is noted for its potential toxicity, especially in environmental contexts. The term has particular application to cadmium, mercury and lead, all of which appear in the World Health Organization's list of 10 chemicals of major public concern. Other examples include manganese, chromium, cobalt, nickel, copper, zinc, silver, antimony and thallium.
Chelation is a type of bonding of ions and molecules to metal ions. It involves the formation or presence of two or more separate coordinate bonds between a polydentate ligand and a single central metal atom. These ligands are called chelants, chelators, chelating agents, or sequestering agents. They are usually organic compounds, but this is not a necessity, as in the case of zinc and its use as a maintenance therapy to prevent the absorption of copper in people with Wilson's disease.
Mercury poisoning is a type of metal poisoning due to exposure to mercury. Symptoms depend upon the type, dose, method, and duration of exposure. They may include muscle weakness, poor coordination, numbness in the hands and feet, skin rashes, anxiety, memory problems, trouble speaking, trouble hearing, or trouble seeing. High-level exposure to methylmercury is known as Minamata disease. Methylmercury exposure in children may result in acrodynia in which the skin becomes pink and peels. Long-term complications may include kidney problems and decreased intelligence. The effects of long-term low-dose exposure to methylmercury are unclear.
Environmental remediation deals with the removal of pollution or contaminants from environmental media such as soil, groundwater, sediment, or surface water. Remedial action is generally subject to an array of regulatory requirements, and may also be based on assessments of human health and ecological risks where no legislative standards exist, or where standards are advisory.
Chelation therapy is a medical procedure that involves the administration of chelating agents to remove heavy metals from the body. Chelation therapy has a long history of use in clinical toxicology and remains in use for some very specific medical treatments, although it is administered under very careful medical supervision due to various inherent risks, including the mobilization of mercury and other metals through the brain and other parts of the body by the use of weak chelating agents that unbind with metals before elimination, exacerbating existing damage. To avoid mobilization, some practitioners of chelation use strong chelators, such as selenium, taken at low doses over a long period of time.
Dimercaprol, also called British anti-Lewisite (BAL), is a medication used to treat acute poisoning by arsenic, mercury, gold, and lead. It may also be used for antimony, thallium, or bismuth poisoning, although the evidence for those uses is not very strong. It is given by injection into a muscle.
Succimer, sold under the brand name Chemet among others, is a medication used to treat lead, mercury, and arsenic poisoning. When radiolabeled with technetium-99m, it is used in a number of types of diagnostic testing. A full course is 19 days of medications by mouth. More than two weeks should pass before a second course is given.
Penicillamine, sold under the brand name of Cuprimine among others, is a medication primarily used for the treatment of Wilson's disease. It is also used for people with kidney stones who have high urine cystine levels, rheumatoid arthritis, and various heavy metal poisonings. It is taken by mouth.
Dithiothreitol (DTT) is the common name for a small-molecule redox reagent also known as Cleland's reagent, after W. Wallace Cleland. DTT's formula is C4H10O2S2 and the chemical structure of one of its enantiomers in its reduced form is shown on the right; its oxidized form is a disulfide bonded 6-membered ring (shown below). The reagent is commonly used in its racemic form, as both enantiomers are reactive. Its name derives from the four-carbon sugar, threose. DTT has an epimeric ('sister') compound, dithioerythritol (DTE).
Boyd Eugene Haley is a retired professor of chemistry at the University of Kentucky.
Acrodynia is a medical condition which occurs due to mercury poisoning. The condition of pain and dusky pink discoloration in the hands and feet is due to exposure or ingesting of mercury. It was known as Pink Disease before it was accepted that it was just mercury poisoning. The word acrodynia is derived from the Greek: ακρος, which means end or extremity, and Greek: οδυνη, which means pain. As such, it might be (erroneously) used to indicate that a patient has pain in the hands or feet. The condition is known by various other names including hydrargyria, mercurialism, erythredema, erythredema polyneuropathy, Bilderbeck's, Selter's, Swift's and Swift-Feer disease.
2,3-Dimercapto-1-propanesulfonic acid and its sodium salt are chelating agents that form complexes with various heavy metals. They are related to dimercaprol, which is another chelating agent.
Metal toxicity or metal poisoning is the toxic effect of certain metals in certain forms and doses on life. Some metals are toxic when they form poisonous soluble compounds. Certain metals have no biological role, i.e. are not essential minerals, or are toxic when in a certain form. In the case of lead, any measurable amount may have negative health effects. It is often thought that only heavy metals can be toxic, but lighter metals such as beryllium and lithium may also be in certain circumstances. Not all heavy metals are particularly toxic, and some are essential, such as iron. The definition may also include trace elements when abnormally high doses may be toxic. An option for treatment of metal poisoning may be chelation therapy, a technique involving the administration of chelation agents to remove metals from the body.
Binding selectivity is defined with respect to the binding of ligands to a substrate forming a complex. Binding selectivity describes how a ligand may bind more preferentially to one receptor than another. A selectivity coefficient is the equilibrium constant for the reaction of displacement by one ligand of another ligand in a complex with the substrate. Binding selectivity is of major importance in biochemistry and in chemical separation processes.
Arsenic biochemistry refers to biochemical processes that can use arsenic or its compounds, such as arsenate. Arsenic is a moderately abundant element in Earth's crust, and although many arsenic compounds are often considered highly toxic to most life, a wide variety of organoarsenic compounds are produced biologically and various organic and inorganic arsenic compounds are metabolized by numerous organisms. This pattern is general for other related elements, including selenium, which can exhibit both beneficial and deleterious effects. Arsenic biochemistry has become topical since many toxic arsenic compounds are found in some aquifers, potentially affecting many millions of people via biochemical processes.
Treatment of the inherited blood disorder thalassemia depends upon the level of severity. For mild forms of the condition, advice and counseling are often all that are necessary. For more severe forms, treatment may consist in blood transfusion; chelation therapy to reverse iron overload, using drugs such as deferoxamine, deferiprone, or deferasirox; medication with the antioxidant indicaxanthin to prevent the breakdown of hemoglobin; or a bone marrow transplant using material from a compatible donor, or from the patient's mother. Removal of the spleen (splenectomy) could theoretically help to reduce the need for blood transfusions in people with thalassaemia major or intermedia but there is currently no reliable evidence from clinical trials about its effects. Population screening has had some success as a preventive measure.
Jeffrey A. Brent is a medical toxicologist who is a distinguished clinical professor of medicine and emergency medicine at the University of Colorado, School of Medicine. In addition, he is a professor at the Department of Environmental and Occupational Health at the Colorado School of Public Health. He is also the past president of the American Academy of Clinical Toxicology, was editor in chief of the journal Toxicological Reviews, and was a member of the board of directors of the American College of Medical Toxicology. Previously, most of Brent's research focused on the use of fomepizole as a treatment for both methanol and ethylene glycol poisoning, and he led a trial of this drug which resulted in the FDA approving it in December 1997. Currently, Brent serves as Director of the Toxicology Investigators Consortium, an NIH and FDA supported multi center research and surveillance group. Brent is also a senior editor of "Critical Care Toxicology: Diagnosis and Management of the Critically Poisoned Patient," originally published in 2005, and now in its second edition, which was published in 2017.
Trine Tsouderos is a journalist who formerly wrote for the Chicago Tribune, beginning in 2003, prior to which she wrote for People, the Tennessean, and the Wilson Daily Times. In 2013, Tsouderos joined PwC's healthcare think tank, Health Research Institute, as a director; in 2021, she was named leader of the institute and also began working as a consultant working on COVID and influenza vaccine projects with pharmaceutical companies. Tsouderos also was co-creator and co-host of PwC's healthcare podcast, Next in Health, and recorded nearly 80 episodes. In 2022, Tsouderos left PwC to work on a master's degree in the history of medicine at Johns Hopkins University School of Medicine.
Doctor's Data, Inc. is a clinical laboratory based in St. Charles, Illinois that is often used by practitioners of alternative medicine.
