Iodine

An essential element in the diet used by the thyroid gland to make thyroid hormones. The two most important thyroid hormones are thyroxine (T4) and triiodothyronine (T3). Thyroxine (T4) has four iodine molecules attached to its structure, while triiodothyronine (T3) has three iodine molecules attached to it. Iodine is found in seafood, bread, salt, and seaweed.

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A nonmetallic chemical element, atomic no. 53, atomic wt. 126.90447; used in the manufacture of i. compounds and as a catalyst, reagent, tracer, constituent of radiographic contrast media, topical antiseptic, antidote for alkaloidal poisons, and in certain stains and solutions; formerly used for prophylaxis of i. deficiency. [G. iodes, violet-like, fr. ion, a violet, + eidos, form]

- butanol-extractable i. (BEI) i. that can be separated from plasma proteins by butanol or other extractable solvents; used to measure thyroid function.

- Gram i. a solution containing i. and potassium iodide, used in Gram stain.

- povidone i. a water soluble complex of i. with polyvinylpyrrolidone. Applied as an antiseptic in the form of solutions or ointments, it releases i.. Used in cleansing and disinfecting the skin, preparing the skin preoperatively, and treating infections susceptible to i.. SYN: polyvinylpyrrolidone-i. complex, povidone-i..

- protein-bound i. (PBI) thyroid hormone in its circulating form, consisting of one or more of the iodothyronines bound to one or more of the serum proteins.

- radioactive i. the i. radioisotopes ¹³¹I, ¹²⁵I, or ¹²³I used as tracers in biology and medicine.

- tamed i. SYN: iodophor.

- i. tincture a hydroalcoholic solution containing 2% elemental i. and 2.4% potassium iodide to facilitate dissolution and 47% alcohol; used as an antiseptic/germicide on the skin surface for cuts and scratches. Has been used as a skin disinfectant before surgery but is now largely replaced by organic forms of i..

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io·dine 'ī-ə-.dīn, -əd-ən, -ə-.dēn n, often attrib

1) a nonmetallic halogen element obtained usu. as heavy shining blackish gray crystals and used esp. in medicine (as in antisepsis and in the treatment of goiter and cretinism) and in photography and chemical analysis symbol I see ELEMENT (table)

2) a tincture of iodine used esp. as a topical antiseptic

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n.

an element required in small amounts for healthy growth and development. An adult body contains about 30 mg of iodine, mostly concentrated in the thyroid gland: this gland requires iodine to synthesize thyroid hormone. A deficiency of iodine leads to goitre. The daily requirement of iodine in an adult is thought to be about 140 µg per day; dietary sources of iodine are sea food and vegetables grown in soil containing iodide and also iodized table salt. Iodine is used in the diagnosis and treatment of diseases of the thyroid gland (see Lugol's iodine, radioactive iodine therapy) and also as an antiseptic and skin disinfectant (in the form of povidone-iodine). Water-soluble contrast media used in X-ray examinations are organic chemicals containing iodine, which is radiopaque due to its high atomic weight. Symbol: I.

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io·dine (I) (iґo-dīn) [Gr. ioeides violetlike, from the color of its vapor] a halogen element of a peculiar odor and acrid taste; atomic number, 53; atomic weight, 126.904. It is a nonmetallic element, occurring in heavy, grayish black plates or granules. Iodine is essential in nutrition, being especially necessary for the synthesis of thyroid hormones (thyroxine and triiodothyronine), which regulate the metabolic rate in all cells. [USP] a preparation of iodine used as a topical antiinfective (see also under solution). Iodine, usually in the form of iodides, is used in the treatment of hyperthyroidism.