Relevance of metallic elements in biomedical contexts
Metals in medicine are used in organic systems for diagnostic and treatment purposes. Inorganic elements are also essential for organic life as cofactors in enzymes called metalloproteins. When metals are under or over-abundant in the body, equilibrium must be returned to its natural state via interventional and natural methods.
Toxic metals.
Metals can be toxic in high quantities. Either ingestion or faulty metabolic pathways can lead to metal toxicity (metal poisoning). Sources of toxic metals include cadmium from tobacco, arsenic from agriculture and mercury from volcanoes and forest fires. Nature, in the form of trees and plants, is able to trap many toxins and can bring abnormally high levels back into equilibrium. Toxic metal poisoning is usually treated with some type of chelating agent. Heavy metal poisoning, such as from mercury, cadmium, or lead, is particularly pernicious.
Examples of specific types of toxic metals include:
Biometals.
Homeostasis.
Fluid and electrolyte balance, in which fluid balance and electrolyte balance are intertwined homeostatically, is necessary to health in all organisms. It includes reference ranges for cation concentrations of biometals, which in reference to human medicine and veterinary medicine principally includes those for blood serum ion concentrations in humans and in livestock and pets. Derangements in such fluid and electrolyte balance most often occur in the contexts of dehydration, overexertion, and diarrhea, but they also occur in cancers (most especially in paraneoplastic syndromes), parasitism, inborn errors of metabolism, and several other contexts. Some medical specialties deal especially frequently with electrolyte derangements, including internal medicine and endocrinology (especially in chronic conditions) and intensive care medicine (in severe acute conditions).
Metal anemia.
Humans need a certain amount of certain metals to function normally. Most metals are used as cofactors or prosthetics in enzymes, catalyzing specific reactions and serving essential roles. The essential metals for humans are: Sodium, Potassium, Magnesium, Copper, Vanadium, Chromium, Manganese, Iron, Cobalt, Nickel, Zinc, Molybdenum, and Cadmium. Anemia symptoms are caused by lack of a certain essential metal. Anemia can be associated with malnourishment or faulty metabolic processes, usually caused by a genetic defect.
Examples of specific types of metal anemia include:
Metals in diagnosis.
Metal complexes in nuclear imaging.
Metal ions are often used for diagnostic medical imaging. Metal complexes can be used either for radioisotope imaging (from their emitted radiation) or as contrast agents, for example, in magnetic resonance imaging (MRI). Such imaging can be enhanced by manipulation of the ligands in a complex to create specificity so that the complex will be taken up by a certain cell or organ type.
Examples of metals used for diagnosis include:
Metal objects in MRI imaging.
An important contraindication to MRI (magnetic resonance imaging) is having metal objects anywhere near, and most especially inside the field of, the MRI scanner. Not only does this entail that people with implanted metal plates, bone screws (internal fixation), or syndesmotic screws often cannot undergo MRI, it also entails that many everyday objects, including jewelry, belt buckles, wallets, purses, security guards' weapons, and so on, must be kept out of the MRI area.
Metals in treatment.
Metals have been used in treatments since ancient times. The Ebers Papyrus from 1500BC is the first written account of the use of metals for treatment and describes the use of Copper to reduce inflammation and the use of iron to treat anemia. Sodium vanadate has been used since the early 20th century to treat rheumatoid arthritis. Recently metals have been used to treat cancer, by specifically attacking cancer cells and interacting directly with DNA. The positive charge on most metals can interact with the negative charge of the phosphate backbone of DNA. Some drugs developed that include metals interact directly with other metals already present in protein active sites, while other drugs can use metals to interact with amino acids with the highest reduction potential.
Examples of metals used in treatment include:
References.
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