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Medical Dictionary - Dictionary of Medicine and Human Biology

Medical Dictionary


involuntary (in-vol′un-tar-e)
1. Independent of the will; not volitional. 2. Contrary to the will. [L. in- neg. + voluntarius, willing, fr. volo, to wish]

involution (in-vo-loo′shun)
1. Return of an enlarged organ to normal size. 2. Turning inward of the edges of a part. 3. In psychiatry, mental decline associated with advanced age. SYN: catagenesis. [L. in-volvo, pp. -volutus, to roll up] senile i. the retrogression of vital organs and psychological processes incident to aging. i. of the uterus the process of reduction of the uterus to its normal nonpregnant size and state following childbirth.

involutional (in-vo-loo′shun-al)
Relating to involution.

iobenzamic acid (i-o-ben-zam′ik)
A radiographic contrast medium formerly used for oral cholecystography.

iocetamic acid (i′o-se-tam′ik)
A radiographic contrast medium formerly used for oral cholecystography.

iodamide (i-o′da-mid)
A radiographic contrast medium formerly used for oral cholecystography. SYN: ametriodinic acid.

Iodamoeba (i-od-a-me′ba)
A genus of parasitic amebae in the superclass Rhizopoda, order Amoebida. I. bütschlii a parasitic ameba in the large intestine of man; trophozoites are usually 9–14 μm in diameter; the cysts are usually 8–10 μm in diameter, uninucleate and somewhat irregular in shape, with a thick wall and a large compact mass of glycogen that stains deeply with a solution of iodine; clinically recognizable amebiasis caused by this organism is rare, with symptoms resembling those of chronic disease caused by Entamoeba histolytica; it is also found in other primates and is the commonest ameba of pigs.

iodate (i′o-dat)
A salt of iodic acid.

iodic (i-od′ik)
1. Relating to, or caused by, iodine or an iodide. 2. Denoting a compound of iodine in its pentavalent state.

iodic acid
Crystalline powder, soluble in water; used as an astringent, caustic, disinfectant, deodorant, and formerly as an intestinal antiseptic.

iodide (i′o-did)
1. The negative ion of iodine, I−. 2. Any salt of hydroiodic acid. 3. Any compound containing an iodine atom linked to a carbon. i. peroxidase an oxidoreductase catalyzing reactions between iodine and water to yield i. and H2O2; also catalyzes iodination and deiodination of tyrosine compounds; a deficiency of this enzyme leads to a loss of the iodotyrosine derivatives and iodine from the thyroid and results in goiter. SYN: iodinase, iodotyrosine deiodase. sodium i. iodine-131 prepared from radioactive iodine (131I); nominally carrier-free, with a half-life of 8.1 days; used as a diagnostic agent in suspected thyroid disease and in the treatment of selected thyroid diseases.

iodimetry (i-o-dim′e-tre)
SYN: iodometry. [iodine + G. metron, measure]

iodinase (i′o-din-as)
SYN: iodide peroxidase.

iodinate (i′o-di-nat)
To treat or combine with iodine.

iodine (I) (i′o-din, -den)
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..

iodine-123 (123I)
A radioisotope of iodine with a 159 keV gamma emission and a physical half-life of 13.2 h, used for studies of thyroid disease and of renal function.

iodine-125 (125I)
Radioactive iodine isotope that decays by K-capture (internal conversion) with a half-life of 59.4 days; used as a label in immunoassay and in imaging; formerly used as a tracer in thyroid studies and as a label in imaging.

iodine-127 (127I)
Stable, nonradioactive iodine, the most abundant iodide isotope found in nature; dietary deficiency causes simple goiter; used to block thyroid uptake of radioactive iodine released from nuclear accidents.

iodine-131 (131I)
A radioactive iodine isotope; beta and gamma emitter with a half-life of 8.1 days; used as a tracer in thyroid studies, as therapy in hyperthyroidism and thyroid cancer, and as a label in immunoassay and imaging; formerly used as therapy in heart disease.

iodine-132 (132I)
A beta- and gamma-emitting radioisotope of iodine with a half-life of 2.28 h, usually obtained from a tellurium-132 radionuclide generator; its clinical use has been supplanted by 131I and 123I.

Denoting hyperthyroidism unresponsive to iodine therapy, which develops frequently in most cases so treated.

iodinophil, iodinophile (i-o-din′o-fil, -fil)
1. Staining readily with iodine. SYN: iodinophilous. 2. Any histologic element that stains readily with iodine. [iodine + G. philos, fond]

iodinophilous (i-o-din-of′i-lus)
SYN: iodinophil (1) .

iodipamide (i-o-dip′a-mid)
An ionic, dimeric, water-soluble radiographic contrast medium for intravenous cholangiography; used as the sodium or methylglucamine salt. SYN: Adipiodone. methylglucamine i. a water-soluble organic iodine compound used for intravenous cholangiography and cholecystography.

iodism (i′o-dizm)
Poisoning by iodine, a condition marked by severe coryza, an acneform eruption, weakness, salivation, and foul breath; caused by the continuous administration of iodine or one of the iodides.

iodixanol (i-o-diks′a-nol)
5,5′-[(2-Hydroxy-1,3-propane)bis(acetylamino)]bis[N,N′-bis(2,3- dihydroxypropyl)-2,4,6- triiodo-1,3-benzenedicarboxamide];a dimeric, nonionic, low osmolar, water-soluble radiographic contrast medium for intravascular use.

iodize (i′o-diz)
To treat or impregnate with iodine.

iodized oil (i′o-dizd)
An iodine addition product of vegetable oils, containing not less than 38% and not more than 42% of organically combined iodine; a radiopaque medium.

iodoacetamide (i-o′do-a-se′ta-mid)
ICH2&cbond;CONH2;a chemical reacting readily with sulfhydryl groups and therefore a strong inhibitor of many enzymes.

iodoalphionic acid (i-o′do-al-fe-on′ik)
A radiographic contrast medium formerly used for cholecystography.

iodocasein (i-o-do-ka′sen)
A compound of iodine with casein, in which the iodine is attached to tyrosine molecules; possesses thyroxine activity.

iodochlorhydroxyquin, iodochlorohydroxyquinoline (i′o-do-klor′hi-drok′si-kwin, -klor′o-hi-drok′si-kwin′o-len)
Topical antiinfective. SYN: chloriodoquin, clioquinol.

iodochlorol (i′o-do-klor′ol)
SYN: chloriodized oil.

iododerma (i-o′do-der′ma)
1An eruption of follicular papules and pustules, or panniculitis, caused by iodine toxicity or sensitivity.

iodoform (i-o′do-form)
A topical antiseptic. SYN: triiodomethane.

iodoglobulin (i-o′do-glob′u-lin)
SYN: thyroglobulin (1) .

iodogorgoic acid (i-o′do-gor-go′ik)
3,5-Diiodotyrosine;a precursor of thyroxine.

iodohippurate sodium (i-o′do-hip′poo-rat)
A radiopaque compound formerly used intravenously, orally, or for retrograde urography. When tagged with iodine-131, it is used to measure effective renal plasma flow and to image the kidneys for radioisotopic renography.

iodomethamate sodium (i-o′do-meth′a-mat)
A high osmolar, ionic, water-soluble, radiographic contrast medium formerly used widely as the disodium salt for intravenous urography.

iodometric (i-o′do-met′rik)
Relating to iodometry.

iodometry (i-o-dom′e-tre)
Analytic techniques involving titrations in which visible form(s) of iodine is either formed or consumed, the sudden appearance or disappearance of iodine marking the end point. SYN: iodimetry. [iodine + G. metron, measure]

iodopanoic acid (i-o′do-pa-no′ik)
SYN: iopanoic acid.

iodophendylate (i-o′do-fen′dil-at)
SYN: iophendylate.

iodophilia (i-o′do-fil′e-a)
An affinity for iodine, as manifested by some leukocytes in certain conditions. When treated with a solution of iodine and potassium iodide, normal polymorphonuclear leukocytes stain a fairly bright yellow; in certain pathologic conditions, the polymorphonuclear leukocytes frequently stain diffusely brown or yellow-brown; the reaction may be intracellular (as described) or extracellular, affecting the particles in the immediate vicinity of the leukocytes. [iodine + G. phileo, to love]

iodophor (i-o′do-for)
A combination of iodine with a surfactant carrier, usually polyvinylpyrrolidone. Commercial preparations generally contain 1% “available” iodine, which is slowly released to take effect against microorganisms; used as skin disinfectants, particularly for surgical scrubs. SYN: tamed iodine. [iodine + G. phora, a carrying]

iodophthalein (i-o′do-thal′en, -dof-thal′e-in)
A radiographic contrast medium. The disodium salt was once used in radiography of the gallbladder. SYN: tetraiodophenolphthalein sodium.

SYN: glyceryl iodide.

iodopropylidene glycerol
SYN: iodinated glycerol.

iodoproteins (i-o′do-pro′tenz)
Proteins containing iodine bound to tyrosyl groups.

iodopsin (i-o-dop′sin)
Any of three visual pigments, composed of 11-cis-retinal bound to an opsin, found in the cones of the retina. SYN: visual violet. [G. ion, violet, + ops, eye, + -in]

iodopyracet (i-o′do-pi′ra-set)
A radiographic contrast medium formerly used for intravenous urography; also used to determine the renal plasma flow and the renal tubular excretory mass. SYN: diodone.

iodoquinol (i-o′do-kwin′ol)
Drug used as an amebicide prepared by the action of iodine monochloride on 8-hydroxyquinoline.

iodotherapy (i′o-do-thar′a-pe)
Treatment with iodine.

iodothyronines (i-o′do-thi′ro-nenz)
Iodinated derivatives of thyronine.

iodotyrosine (i-o′do-ti′ro-sen)
An iodinated tyrosine. i. deiodase SYN: iodide peroxidase.

iodoxamate meglumine (i-o-doks′a-mat)
The methylglucamine salt of an ionic, water-soluble, dimeric, radiographic contrast medium; formerly used primarily for intravenous cholangiography.

ioduria (i-o-doo′re-a)
Urinary excretion of iodine.

ioglycamic acid (i′o-gli-kam′ik)
3,3′-[oxybis(methylene carbonylimino)]bis[2,4,6-triiodobenzoic acid];an ionic, water-soluble, dimeric, radiographic contrast medium, formerly used for intravenous cholangiography.

iohexol (i′o-heks′ol)
A monomeric, nonionic, water-soluble, low osmolar radiographic contrast medium for urography or angiography. Used intrathecally and intravascularly.

iometer (i-om′e-ter)
An apparatus for measuring ionization. [ion + G. metron, measure]

ion (i′on)
An atom or group of atoms carrying an electric charge by virtue of having gained or lost one or more electrons. Ions charged with negative electricity (anions) travel toward a positive pole (anode); those charged with positive electricity (cations) travel toward a negative pole (cathode). Ions may exist in solid, liquid, or gaseous environments, although those in liquid (electrolytes) are more common and familiar. [G. i., going] aquo-i. aquo-i.. dipolar ions ions possessing both a negative charge and a positive charge, each localized at a different point in the molecule, which thus has both positive and negative “poles”; amino acids are the most notable dipolar ions, containing a positively charged NH3+ group and a negatively charged COO− group at neutral pH. SYN: amphions, zwitterions. gram-i. gram-i.. hydride i. the H− i., transferred to acceptor molecules in some biologic oxidations. hydrogen i. (H+) a hydrogen atom minus its electron and therefore carrying a unit positive charge ( i.e., a proton); in water, it combines with a water molecule to form hydronium i., H3O+. hydronium i. the hydrated proton, H3O+, a form in which hydrogen i. exists in aqueous solutions; also, H3O+&chmpnt;H2O, H3O+&chmpnt;2H2O, etc. SYN: oxonium i.. oxonium i. SYN: hydronium i.. sulfonium i. a compound in which a sulfur atom has three single covalent bonds and therefore has a positive charge analogous to the nitrogen of an ammonium compound; e.g., S-adenosyl-l-methionine.

See Jonnesco.

ion exchange (i′on eks-chanj′)
See anion exchange, cation exchange, i. chromatography.

ion exchanger (i′on eks-chanj′er)
See anion exchanger, cation exchanger.

ionic (i-on′ik)
Relating to an ion.

ionium (i-o′ne-um)
Former term for thorium-230. [G. ion, going]

ionization (i′on-i-za′shun)
1. Dissociation into ions, occurring when an electrolyte is dissolved in water or certain liquids or when molecules are subjected to electrical discharge or ionizing radiation. 2. Production of ions as a result of interaction of radiation with matter. 3. SYN: iontophoresis.

ionize (i′on-iz)
To separate into ions; to dissociate atoms or molecules into electrically charged atoms or radicals.

ionogram (i′on-o-gram)
SYN: electropherogram.


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