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Medical Dictionary


menyanthes (men-yan′thez)
SYN: buckbean.

mepacrine hydrochloride (mep′a-kren)
SYN: quinacrine hydrochloride.

mepazine acetate (mep′a-zene)
A phenothiazine derivative with actions and uses similar to those of chlorpromazine. Also available as m. hydrochloride.

mepenzolate bromide (me-pen′zo-lat)
An anticholinergic drug.

meperidine hydrochloride (me-per′i-den)
A widely used narcotic analgesic. SYN: pethidine.

mephenesin (me-fen′e-sin)
A centrally acting skeletal muscle relaxant; also available as m. carbamate.

mephentermine (me-fen′ter-men)
A sympathomimetic amine. m. sulfate used topically as a nasal decongestant and systemically for its pressor effects in acute hypotensive states.

mephenytoin (me-fen′i-to-in)
An anticonvulsant used when safer agents prove inadequate; used in drug metabolism studies.

mephitic (me-fit′ik)
Foul, poisonous, or noxious. [L. mephitis, a noxious exhalation]

mephobarbital (mef-o-bar′bi-tawl)
Used as a sedative and long-acting hypnotic, and as an anticonvulsant in the management of epilepsy; converted to phenobarbital in the body.

mepivacaine hydrochloride (me-piv′a-kan)
A local anesthetic agent.

meprobamate (me-pro′ba-mat)
A skeletal muscle relaxant with action similar to that produced by mephenesin but of longer duration; used in the management of certain disorders associated with abnormal motor activity, as a mild hypnotic, and as an antianxiety agent.

meptazinol (mep-taz′i-nol)
A narcotic analgesic mixed agonist/antagonist (like pentazocine) which is about one-tenth as potent as morphine in producing analgesia. Though its abuse potential is less than that of pure agonists, the drug can precipitate an abstinence syndrome in persons dependent on opioids.

mepyramine maleate (me-pir′a-men)
SYN: pyrilamine maleate.

mepyrapone (me-pir′a-pon)
SYN: metyrapone.

mEq, meq
Abbreviation for milliequivalent.

1. Chemical suffix attached to a prefix such as mono-, di-, poly-, tri-, etc., to indicate the smallest unit of a repeating structure; e.g., polymer. 2. Suffix denoting a member of a particular group; e.g., isomer, enantiomer.

meralgia (me-ral′je-a)
Pain in the thigh; specifically, m. paresthetica. [G. meros, thigh, + algos, pain] m. paresthetica burning pain, tingling, pruritus, or formication along the lateral aspect of the thigh in the distribution of the lateral femoral cutaneous nerve due to entrapment of that nerve; affected skin area often is hyperesthetic. SYN: Bernhardt disease, Bernhardt-Roth syndrome.

meralluride (mer-al′u-rid)
A mercurial diuretic.

merbromin (mer-bro′min)
The disodium salt of 2,7-dibromo-4-hydroxymercurifluorescein; an organic mercurial antiseptic compound that also has staining properties similar to those of eosin and phloxine, with strong affinity for cytoplasmic structures; also used histochemically to stain protein-bound sulfhydryl and disulfide groups for bright-field and fluorescence microscopy. SYN: mercurochrome.

mercaptal (mer-kap′tal)
A substance derived from an aldehyde by the replacement of the bivalent oxygen by two thioalkyl (–SR) groups.

mercaptan (mer-kap′tan)
1. A class of substances in which the oxygen of an alcohol has been replaced by sulfur ( e.g., cysteine). SYN: thioalcohol. See thiol. 2. In dentistry, a class of elastic impression compounds sometimes referred to as rubber base materials. methyl m. formed in the intestines by bacterial action on sulfur-containing proteins and appears in urine after ingestion of asparagus (contributing to the characteristic odor); also used in the manufacture of various organic sulfur-containing pesticides and fungicides.

Prefix indicating the presence of a thiol group, –SH.

mercaptoacetic acid (mer-kap′to-a-se′tik)
SYN: thioglycolic acid.

mercaptoethanol (mer-kap′to-eth′a-nol)
A commonly used reducing agent.

2-mercaptoethanol (mer-kap′to-eth-an-ol)
A reagent used to reduce disulfide bonds, particularly in proteins, and to prevent their formation. SYN: β-mercaptoethanol.

mercaptol (mer-kap′tol)
A substance derived from a ketone by the replacement of the bivalent oxygen by two thioalkyl (–SR) groups.

3-mercaptolactate (mer-kap′to-lak-tat)
A product of cysteine catabolism; formed by the action of lactate dehydrogenase on 3-mercaptopyruvate that was, in turn, formed by transamination of cysteine; present in normal human urine as a mixed disulfide with cysteine; elevated in the urine in individuals with mercaptolactate-cysteine disulfiduria.

mercaptolactate-cysteine disulfiduria
Elevated levels of the mixed disulfide of 3-mercaptolactate and cysteine in the urine.

mercaptomerin sodium (mer-kap-tom′e-rin, mer-kap-to-mer′in)
A mercurial diuretic.

6-mercaptopurine (Shy) (mer-kap-to-poor′en)
An analogue of hypoxanthine and of adenine; an antineoplastic agent.

3-mercaptopyruvate (mer-kap′to-pi-roo-vat)
The transaminated product of cysteine; formed in cysteine catabolism; elevated in individuals with a deficiency of m. sulfurtransferase. 3-mercaptopyruvate sulfurtransferase an enzyme that is a part of the cysteine catabolic pathway; it catalyzes the conversion of m. to pyruvate and H2S; a deficiency of this enzyme will result in elevated urine concentrations of m. as well as of 3-mercaptolactate, both in the form of disulfides with cysteine.

mercapturic acid (mer-kap-tur′ik)
A condensation product of l-cysteine with aromatic compounds, such as bromobenzene, and usually acetylated; formed biologically via glutathione in the liver and excreted in the urine; an S-substituted N-acetylated l-cysteine. Cf.:m. pathway.

Louis A., French urologist, 1811–1882. See M. bar, M. sound, M. valve, median bar of M..

mercocresols (mer-ko-kre′solz)
A mixture consisting of equal parts by weight of sec-amyltricresol and o-hydroxy-phen-ylmercuric chloride; it possesses fungicidal, germicidal, and bacteriostatic action.

mercumatilin (mer′ku-ma-til′in, -mat′i-lin)
A mercurial diuretic; also available as m. sodium.

mercuramide (mer-koo′ra-mid)
SYN: mersalyl.

mercurial (mer-ku′re-al)
1. Relating to mercury. 2. Any salt of mercury used medicinally. 3. Having the characteristic of rapid, changing moods.

mercurialentis (mer-ku′re-a-len′tis)
A brown discoloration of the anterior capsule of the lens caused by mercury; early sign of mercurial poisoning.

mercurialism (mer-ku′re-a-lizm)
SYN: mercury poisoning.

mercuric (mer-ku′rik)
Denoting a salt of mercury in which the ion of the metal is bivalent, as in corrosive sublimate, m. chloride, HgCl2; the mercurous chloride is calomel, HgCl.

mercuric chloride
A topical antiseptic and disinfectant for inanimate objects. SYN: corrosive sublimate, mercury bichloride, mercury perchloride, corrosive mercury chloride. ammoniated m. SYN: ammoniated mercury.

mercuric iodide, red
Has been used as an antiseptic and as a disinfectant for inanimate objects. SYN: mercury biniodide, mercury deutoiodide.

mercuric oleate
An ointment-like preparation used in parasitic skin diseases.

mercuric oxide, red
The red precipitate of HgO; it has been used externally as an antiseptic in chronic skin diseases and fungus infections. SYN: red precipitate.

mercuric oxide, yellow
The yellow precipitate of HgO; used externally as an antiseptic in the treatment of inflammatory conditions of the eyelids and the conjunctivae. SYN: yellow precipitate.

mercuric salicylate
A powder used externally in the treatment of parasitic and fungus skin diseases. SYN: mercury subsalicylate.

mercurochrome (mer-kur′o-krom)
SYN: merbromin.

mercurophen (mer-ku′-ro-fen)
A local antiseptic.

mercurophylline sodium (mer-kur-of′i-len)
The sodium salt of β-methoxy-γ-hydroxymercuripropylamide of trimethylcyclopentanedicarboxylic acid, and theophylline; a mercurial diuretic.

mercurous (mer-ku′rus, mer′ku-rus)
Denoting a salt of mercury in which the ion of the metal is univalent, as in calomel, m. chloride, HgCl; the mercuric chloride is corrosive sublimate, HgCl2.

mercurous chloride
SYN: calomel.

mercurous iodide
Used externally as an ointment in eye diseases. SYN: mercury protoiodide, yellow mercury iodide.

mercury (Hg) (mer′ku-re)
A dense liquid metallic element, atomic no. 80, atomic wt. 200.59; used in thermometers, barometers, manometers, and other scientific instruments; some salts and organic mercurials are used medicinally; care must be followed with its handling; 197Hg (half-life of 2.672 days) and 203Hg (half-life of 46.61 days) have been used in brain and renal scanning. SYN: hydrargyrum, quicksilver. [L. Mercurius, M., the god of trade, messenger of the gods; in Mediev. L., quicksilver, m.] ammoniated m. used in ointment for the treatment of skin diseases. SYN: ammoniated mercuric chloride, white mercuric precipitate. m. bichloride, m. perchloride, corrosive m. chloride SYN: mercuric chloride. m. biniodide SYN: mercuric iodide, red. m. deutoiodide SYN: mercuric iodide, red. m. protoiodide SYN: mercurous iodide. m. subsalicylate SYN: mercuric salicylate. yellow m. iodide SYN: mercurous iodide.

mere-, mero-
Part; also indicating one of a series of similar parts. SEE ALSO: -mer. [G. meros, share]

K. Alvin, U.S. surgeon, 1914–1985. See M. technique.

mereprine (mer′e-pren)
SYN: doxylamine succinate.

J., Finnish physician. See M. syndrome.

meridian (me-rid′-e-an)
1. [TA] A line encircling a globular body at right angles to its equator and touching both poles, or the half of such a circle extending from pole to pole. SYN: meridianus [TA] . 2. In acupuncture, the lines connecting different anatomical sites. [L. meridianus, pertaining to midday, on the south side, southern] m. of cornea any line bisecting the cornea through its apex. meridians of eyeball [TA] lines surrounding the surface of the eyeball passing through both anterior and posterior poles. SYN: meridiani bulbi oculi [TA] .

meridiani (me-rid-e-a′ni)
Plural of meridianus.

meridianus, pl .meridiani (me-rid′e-a′nus, -ni) [TA]
SYN: meridian (1) . [L.] meridiani bulbi oculi [TA] SYN: meridians of eyeball, under meridian.

meridional (me-rid′e-o-nal)
Relating to a meridian.

merispore (mer′i-spor)
A secondary spore, one resulting from the segmentation of another (compound or septate) spore. [G. meros, a part, + sporos, seed]

meristematic (mer′is-te-mat′ik)
Pertaining (in fungi) to an area (meristem) of the hyphae or of other specialized structures from which new growth occurs. [G. merizein, to divide]

meristic (me-ris′tik)
Symmetrical; that which can be divided evenly; denoting bilateral or longitudinal symmetry in the arrangement of parts in one organism. [G. meristikos, suitable for dividing]

Karl L., German anatomist and laryngologist, 1812–1876. See M. filtrum ventriculi, M. fossa, M. muscle.

Friedrich S., German anatomist and physiologist, 1845–1919. See M. cell tumor, M. corpuscle, M. tactile cell, M. tactile disk.

Mermis (mer′mis)
Genus of long, opaque nematodes; larval stages passed in the hemocylic cavity of insects, particularly grasshoppers, while adults are free-living in the soil. Accidental ingestion by humans causes infection. M. nigrescens nematode species found in soil that deposits eggs on above-ground plants; normal host grasshoppers; has been recovered from alimentary and urogenital tracts of humans but infections are rare.

See mere-.

meroacrania (mer′o-a-kra′ne-a)
Congenital lack of a part of the cranium other than the occipital bone. [mero- + G. a- priv. + kranion, skull]


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