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Medical Dictionary


methemalbuminemia (met′hem-al-boo-min-e′me-a)
The presence of methemalbumin in the circulating blood, indicative of intravascular hemolysis with rapid hemoglobin breakdown; found in some patients with blackwater fever or paroxysmal nocturnal hemoglobinuria; described as a means of differentiating severe (hemorrhagic) from mild (edematous) pancreatitis, and also has been described in other acute conditions such as strangulation obstruction of intestine and mesenteric artery occlusion.

methemoglobin (metHb) (met-he-mo-glo′bin)
A transformation product of oxyhemoglobin because of the oxidation of the normal Fe2+ to Fe3+, thus converting ferroprotoporphyrin to ferriprotoporphyrin; it contains water in firm union with ferric iron, thus being chemically different from oxyhemoglobin and useless for respiration; found in sanguineous effusions and in the circulating blood after poisoning with acetanilid, potassium chlorate, and other substances. SYN: ferrihemoglobin. m. reductase a flavoenzyme catalyzing the reduction of m. to hemoglobin in the red blood cell.

methemoglobinemia (met-he′mo-glo-bi-ne′me-a, meth′e-mo-)
The presence of methemoglobin in the circulating blood; when severe, there is inadequate oxygenation of the tissues. Methemoglobin causes the blood to have a brownish color, which may be mistaken for cyanosis. [methemoglobin + G. haima, blood] acquired m. m. caused by various chemical agents, such as nitrites or topical anesthetics. SYN: enterogenous m., secondary m.. congenital m. 1. m. due to formation of any one of a group of abnormal α chain [MIM*141800] or β chain [MIM*141900] hemoglobins collectively known as hemoglobin M. Slate-gray cyanosis occurs in early infancy, without pulmonary or cardiac disease, and is resistant to ascorbic acid or methylene blue therapy; autosomal dominant inheritance; 2. m. due to deficiency of cytochrome b5 reductase [MIM*250790] or methemoglobin reductase [MIM*250700], the enzyme responsible for reduction of intraerythrocyte methemoglobin; cyanosis is improved by ascorbic acid or methylene blue; autosomal recessive inheritance; SYN: hereditary m., hereditary methemoglobinemic cyanosis, primary m.. enterogenous m. SYN: acquired m.. hereditary m. SYN: congenital m.. primary m. SYN: congenital m.. secondary m. SYN: acquired m..

methemoglobinuria (met-he′mo-glo-bi-noo′re-a, meth′e-mo-)
The presence of methemoglobin in the urine. [methemoglobin + G. ouron, urine]

methenamine (me-then′a-men)
A condensation product obtained by the action of ammonia upon formaldehyde; in an acid urine, it decomposes to yield formaldehyde, a urinary antiseptic. SYN: hexamine. m. hippurate a urinary antiseptic. m. mandelate a urinary antiseptic. m. salicylate a uric acid solvent and urinary antiseptic.

A hexamethylenetetramine-silver complex prepared by adding silver nitrate to methenamine; a white precipitate appears in the solution which dissolves upon shaking and is stable under refrigeration; used in various histological and histochemical staining methods. SEE ALSO: Gomori methenamine-silver stain, under stain.

methene (meth′en)
The moiety &dbond;CH&cbond;.

SYN: metergoline.

methicillin sodium (meth-i-sil′in)
A semisynthetic penicillin salt for parenteral administration; restriction of its use to infections caused by penicillin G-resistant staphylococci is recommended; it is less effective than penicillin G in infections caused by hemolytic streptococci, pneumococci, gonococci, and penicillin G-sensitive staphylococci. SYN: sodium methicillin.

methimazole (me-thim′a-zol)
An antithyroid drug similar in action to propylthiouracil.

methiodal sodium (meth-i′o-dal)
An iodine-containing radiopaque medium, CH2ISO3Na or sodium methanesulfonate, formerly used for examination of the urinary tract.

methionine (Met, M) (me-thi′o-nen)
2-Amino-4-(methylthio)butyric acid;the l-isomer is a nutritionally essential amino acid and the most important natural source of “active methyl” groups in the body, hence usually involved in methylations in vivo; the dl-form is used as an adjunct in the treatment of liver diseases. active m. SYN: S-adenosyl-l-m.. m. adenosyltransferase an enzyme catalyzing the condensation of l-m. and ATP, forming S-adenosyl-l-m., orthophosphate, and pyrophosphate; a deficiency of the hepatic enzyme will result in hypermethionemia. SYN: m.-activating enzyme. m. sulfoxime a toxic derivative of m. formed when proteins containing it are treated with nitrogen chloride to give –SO(NH)CH3 in place of –SCH3. m. synthase tetrahydropteroylglutamate methyltransferase; m.-homocysteine methyltransferase;an enzyme that catalyzes the reaction of N5-methyltetrahydrofolate with l-homocysteine to form tetrahydrofolate and l-m.; a cobalamin-requiring enzyme; a deficiency of this enzyme results in an accumulation of l-homocysteine and neurological abnormalities. SYN: tetrahydrofolate methyltransferase.

methisazone (me-this′a-zon)
An antiviral agent.

methitural (me-thi′t-oo-ral)
An intravenous thiobarbiturate resembling thiopental and used for the induction of anesthesia; exerts a brief effect due to rapid redistribution in the body after a single injection.

methixene hydrochloride (me-thik′sen)
An anticholinergic agent.

See meth-.

methocarbamol (meth-o-kar′ba-mol)
A centrally acting skeletal muscle relaxant, chemically related to mephenesin carbamate; it is slower in onset of action but of longer duration, and may be administered intravenously, intramuscularly, or orally.

method (meth′od)
The mode or manner or orderly sequence of events of a process or procedure. SEE ALSO: fixative, operation, procedure, stain, technique. [G. methodos; fr. meta, after, + hodos, way] Abell-Kendall m. a standard reference m. for estimation of total serum cholesterol involving saponification of cholesterol ester by hydroxide, extraction with petroleum ether, and color development with acetic anhydride-sulfuric acid; the m. avoids interference by bilirubin, protein, and hemoglobin. activated sludge m. a m. of sewage disposal in which the sewage is treated with 15% bacterially active, liquid sludge, which is produced by repeated vigorous aeration of fresh sewage to form floccules or sediment; when this flocculation process is complete, the resulting activated sludge contains large numbers of bacteria, together with yeasts, molds, and protozoa, which actively effect the oxidation of organic compounds; this mixture is piped to a sedimentation tank, the effluent from which is completely treated sewage. Altmann-Gersh m. the m. of rapidly freezing a tissue and dehydrating it in a vacuum. Anel m. ligation of an artery immediately above (on the proximal side of) an aneurysm. Antyllus m. ligation of the artery above and below an aneurysm, followed by incision into and emptying of the sac. aristotelian m. a m. of study that stresses the relation between a general category and a particular object. Ashby m. a differential agglutination m. for estimating erythrocyte life span; compatible blood possessing a group factor that the recipient lacks is transferred to the recipient; after the transfusion, sera with potent agglutinins for the recipient's red cells are added to samples of the recipient's blood, and the unagglutinated red cells are counted; using this technique the red cell life span in normal persons is found to be 110–120 days. auxanographic m. a m. for the study of bacterial enzymes in which agar is mixed with the material ( e.g., starch or milk) which is to serve as an indicator of the enzyme action and is inoculated and plated; if the bacteria produce enzymes digesting the admixed material, there will be a zone of clearing in the medium about each colony. SYN: diffusion m.. Barraquer m. SYN: zonulolysis. Beck m. a permanent opening into the stomach made from its greater curvature. Bier m. 1. SYN: intravenous regional anesthesia. 2. treatment of various surgical conditions by reactive hyperemia. Billings m. a contraceptive m. that involves periods of abstinence determined by changes in cervical mucus. Born m. of wax plate reconstruction the making of three-dimensional models of structures from serial sections; it depends on the building up of a series of wax plates, cut out to scaled enlargements of the individual sections involved in the region to be reconstructed. Brasdor m. treatment of aneurysm by ligation of the artery immediately below (on the distal side of) the tumor. Callahan m. SYN: chloropercha m.. capture-recapture m. originally, a technique developed by biologists to track wild animal populations; now adapted for epidemiological studies of elusive human populations ( e.g., prostitutes, teen runaways, IV drug users). Charters m. a m. of toothbrushing utilizing a restricted circular motion with the bristles inclined coronally at a 45 degree angle. Chayes m. a m. of replacing lost teeth utilizing a mechanical device for the fixation and stabilization of the dental prosthesis which allows “movement in function” of the abutment teeth. chloropercha m. a m. of filling the root canals of teeth by dissolving gutta-percha cones in a chloroform-rosin medium within the root canal. SYN: Callahan m., Johnson m.. closed circuit m. a m. for measuring oxygen consumption in which the subject rebreathes an initial quantity of oxygen through a carbon dioxide absorber and the decrease in the volume of oxygen being rebreathed is noted. Cobb m. a technique used in scoliosis to determine the degree of curvature of the spine; the measurement is made by drawing a perpendicular to a line drawn across the superior endplate of the upper-end (most tilted) vertebra and the inferior endplate of the lower-end vertebra; the angle formed by the intersection of the two perpendicular lines is the Cobb angle, which is the measure of the magnitude of the curve. combined methods varying combinations of the oral auditory m. and the manual visual m. of education of deaf children. SEE ALSO: oral auditory m., manual visual m., total communication. confrontation m. a m. of perimetry; the examiner compares the patient's visual fields with the examiner's own by facing the patient who has one eye covered and the other fixed upon the corresponding (confronting) eye of the examiner. The examiner then holds a finger midway between them and moves it slowly in different directions until the patient fails to see it. In each instance the finger is moved again toward the original position until the patient can just see it. cooled-knife m. the cutting of frozen sections with a knife cooled to a few degrees below the freezing point. copper sulfate m. a m. for the determination of specific gravity of blood or plasma in which the blood or plasma is delivered by drops into solutions of copper sulfate graded in specific gravity by increments of 0.004, each of the bottles of solution being within the expected range of the blood or plasma sample; the specific gravity of the copper sulfate solution in which the drop of blood or plasma remains suspended indefinitely indicates the specific gravity of the sample. correlational m. a statistical m., most often used in clinical and other applied areas of psychology, to study the relationship which exists between one characteristic and another in an individual. Credé methods 1. instillation of one drop of a 2% solution of silver nitrate into each eye of the newborn infant, to prevent ophthalmia neonatorum; 2. resting the hand on the fundus uteri from the moment of the expulsion of the fetus, and gently rubbing in case of hemorrhage or failing contraction; then, when the afterbirth is loosened it is expelled by firm compression or squeezing of the fundus by the hand; 3. use of manual pressure on a bladder, particularly a paralyzed bladder, to express urine. SYN: Credé maneuvers. cross-sectional m. in developmental psychology, the study of the life span involving comparison of groups of individuals at different age levels. Cf.:longitudinal m.. Deaver m. a m. of motor reeducation. definitive m. an analytical procedure for the measurement of a specified analyte in a specified material which is known to give essentially the true value for the concentration of the analyte. Dick m. SYN: Dick test. diffusion m. SYN: auxanographic m.. direct m. for making inlays in dentistry, an inlay technique in which the wax pattern is made directly in the prepared cavity in the tooth. SYN: direct technique. disk sensitivity m. a procedure for testing the relative effectiveness of various antibiotics; small disks of paper (or other suitable material) are impregnated with known, appropriate amounts of antibiotic, and then placed on the surface of semisolid medium that has been previously inoculated with the organism being tested; after suitable periods of incubation at 37°C, the lack of growth in zones about the various disks indicates the relative effectiveness of the antibiotic. double antibody m. SYN: double antibody precipitation. Edman m. phenylisothiocyanate. Eggleston m. obsolete term for rapid digitalization by means of large doses of digitalis leaf or tincture frequently repeated. Eicken m. facilitation of hypopharyngoscopy by means of forward traction on the cricoid cartilage by a laryngeal probe. encu m. a means of simplifying the calculation of risk in genetic counseling for autosomal dominant traits by converting all pertinent evidence into encu units. ensu m. a means of simplifying the calculation of risk in genetic counseling for X-linked traits by converting all pertinent evidence into ensu units. experimental m. in experimental psychology, control of environmental, physiological, or attitudinal factors to observe dependent changes in aspects of experience and behavior. Fick m. in 1870 A. Fick proposed that cardiac output can be calculated as the quotient of total body oxygen consumption divided by the difference in oxygen content of arterial blood and mixed venous blood. In the direct Fick m. all variables are measured. The indirect Fick m. employs a variety of means to avoid measuring mixed venous oxygen content. By extension, the Fick m. may be used to measure cardiac output or organ blood flow with any indicator substance for which the rate of uptake or consumption, and the arterial and mixed venous concentrations, can be measured, provided the indicator does not enter or leave the system by any route not being measured. SYN: Fick principle. flash m. sterilization of milk by raising it rapidly to a temperature of 178°F, holding it there for a short time, and reducing it rapidly to 40°F. flotation m. any of several procedures for concentrating helminth eggs for more reliable results when eggs are difficult to find in direct examination; the flotation methods depend on flotation of helminth eggs on the surface of a liquid of sufficiently high specific gravity, approximately 1.180; 1 part feces mixed in about 10 parts saturated saline will float most protozoan cysts and nonoperculated helminth eggs. SEE ALSO: zinc sulfate flotation centrifugation m.. Gärtner m. a m. of measuring venous pressure, based upon Gärtner vein phenomenon; with the patient sitting erect, a vein is selected on the back of the hand that is held dependent, well below the level of the right atrium, and then is raised slowly; when the vein is observed to collapse, the distance between its level and that of the atrium is measured with a millimeter rule; this distance gives the venous pressure in millimeters of blood; thus the vein itself is used as a manometer communicating with the right atrium; highly inaccurate, especially in elderly subjects. Gerota m. injection of the lymphatics with a dye that is soluble in chloroform or ether but not in water; alkannin, red sulfide of mercury, and Prussian blue are said to be suitable for this purpose. glucose oxidase m. a highly specific m. for measurement of glucose in serum or plasma by reaction with glucose oxidase, in which gluconic acid and hydrogen peroxide are formed. Gruber m. a modification of the Politzer m. in which the patient does not swallow, but says “hoc” at the instant of compression of the bag. Hamilton-Stewart m. formula to calculate cardiac output after intravenous indicator dye injection; blood flow in liters per minute is given by dividing the amount of injectant in milligrams by the product of the average dye concentration in the initial curve of the dye concentration sampled at a given point in the circulation and multiplied by the dose of dye (in milligrams) to write the curve from appearance to disappearance (in the absence of any recirculation). SYN: Hamilton-Stewart formula, indicator dilution m., Stewart-Hamilton m.. Hammerschlag m. a hydrometric m. of determining the specific gravity of the blood by allowing a drop of blood to fall into each of a series of tubes containing mixtures of chloroform and benzene of known graded specific gravities; the specific gravity of that mixture in which the drop remains exactly suspended, neither rising nor falling, corresponds to the specific gravity of the blood sample. hexokinase m. the most specific m. for measuring glucose in serum or plasma, wherein hexokinase plus ATP transforms glucose to glucose 6-phosphate plus ADP; glucose 6-phosphate is then reacted with NADP and glucose 6-phosphate dehydrogenase to form NADP which is measured spectrophotometrically. Hilton m. division of the nerves supplying a part, for the relief of pain in ulcers. Hirschberg m. a m. of measuring the amount of deviation of a strabismic eye, by observing the reflection of a light fixated by the straight eye on the cornea of the deviating eye. Hung m. SYN: Wilson m.. immunofluorescence m. any m. in which a fluorescent-labeled antibody is used to detect the presence or determine the location of the corresponding antigen. impedance m. a m. for localizing brain structures by measuring impedance of electric current. indicator dilution m. SYN: Hamilton-Stewart m.. indirect m. for making inlays a m. whereby the inlay is constructed entirely on a model made from an impression of the prepared tooth or teeth in the mouth. SYN: indirect technique. indophenol m. a m. of determining quantitatively the amount of vitamin C in plant and animal tissue based on the rapid reduction of a standardized indophenol solution to a colorless compound by vitamin C in acid solution. introspective m. in functionalism, the systematic study of mental phenomena by contemplating the processes in one's own conscious experiences. ITO m. a concise matrix m. for computing the distribution of genotypes of relatives that at one locus may share no genes in common, one, or both. Johnson m. SYN: chloropercha m.. Keating-Hart m. fulguration in the treatment of external cancer or of the field of operation after the removal of a malignant growth. Kety-Schmidt m. a m. for measuring organ blood flow first applied to the brain in 1944 by C. F. Schmidt and S. S. Kety. A chemically inert indicator gas is equilibrated with the tissue of the organ of interest and the rate of disappearance from the organ is measured. Blood flow is calculated on the assumption that the tissue and venous blood concentrations of the indicator gas are in diffusion equilibrium at all blood flow rates and that the rate of disappearance of the indicator from the tissue is a function of how much is in the tissue at any time, i.e., it is assumed to be an exponential disappearance. Kjeldahl m. macro-Kjeldahl m., micro-Kjeldahl m.. Lamaze m. a technique of psychoprophylactic preparation for childbirth, designed to minimize the pain of labor. Langendorff m. perfusion of the isolated mammalian heart by carrying fluid under pressure into the sectioned aorta, and thus into the coronary system. Lee-White m. a m. for determining coagulation time of venous blood in tubes of standard bore at body temperature. Liborius m. a m. for culturing anaerobic bacteria; a stab culture is made in the appropriate agar medium, then more of the same medium is liquefied and poured into the test tube on top of the stab culture, effectually sealing it from the air. Ling m. gymnastic exercises (as in Swedish movements) without the use of apparatus. Lister m. antiseptic surgery, as first advocated by Lister in 1867; his operations were performed under a cloud of diluted carbolic acid spray, the instruments were dipped in a carbolic solution before use, and the wound was dressed with a thick layer of carbolized gauze; from this was developed the present practice of aseptic surgery. SYN: listerism. lod m. a m. of linkage analysis using an examination of the common logarithm of the ratio of the likelihood for a particular value of the recombination fraction to that if the recombination fraction is 0.5 ( i.e., no linkage); thus, a lod score of 3 at a recombination fraction of 0.2 means that the data are 1000 times more readily explained by supposing a recombination fraction of 0.2 than by supposing the loci are unlinked and the recombination fraction is 0.5. [logarithm of the odds] longitudinal m. in developmental psychology, the study of the life span of one individual involving comparisons of different age levels. Cf.:cross-sectional m.. macro-Kjeldahl m. a procedure for analyzing the content of nitrogenous compounds in urine, serum, or other specimens, usually to determine relatively large amounts of nitrogen ( e.g., 20–100 mg); the specimen is treated with a digestion mixture (copper sulfate and sulfuric acid), heated thoroughly, and made alkaline with a solution of sodium hydroxide; ammonia is then distilled from the mixture, trapped in a boric acid-indicator solution, and titrated with standard hydrochloric or sulfuric acid. manual visual m. an approach to the education of deaf children that emphasizes the role of vision in communication and the early and consistent use of ASL or other national sign languages. SEE ALSO: oral auditory m., combined methods, total communication. Marshall m. a quantitative procedure for estimating free and conjugated sulfanilamide in body fluids. micro-Astrup m. an interpolation technique for acid-base measurement, based on pH and the use of the Siggaard-Andersen nomogram to determine the base deficit as an expression of metabolic acidosis and the arterial PCO2 as an expression of respiratory acidosis or alkalosis. micro-Kjeldahl m. a modification of the macro-Kjeldahl m. designed for the analysis of nitrogenous compounds in relatively small quantities, e.g., specimens in which the total content of nitrogen is in the range of 1 to a few milligrams. microsphere m. a m. for measuring organ blood flow by indicator dilution, but more importantly, a m. for measuring the distribution of cardiac output or the intraorgan distribution of blood flow. To measure distribution of flow, neutrally buoyant, chemically inert microspheres that have an indicator property ( e.g., radioactivity) are injected into a cardiac chamber or arterial blood. They are presumed to distribute in proportion to the distribution of arterial blood flow. Injected sphere size is selected to be large enough to embolize the vessels of interest. Injected quantity is selected to be large enough to provide statistically meaningful samples and small enough not to alter the organ blood flow under investigation. Organ samples are taken to quantify the distribution of the microspheres and hence the flow. See Fick m., Stewart-Hamilton m.. Moore m. treatment of aneurysm by the introduction of silver or zinc wire into the sac to induce fibrin deposition. Needles split cast m. SYN: split cast m.. Nikiforoff m. the fixing of blood films by immersion for 5 to 15 minutes in absolute alcohol, a mixture of equal parts of alcohol and ether, or pure ether. Ochsner m. an obsolete treatment for appendicitis (by peristaltic rest), when surgery is not advisable. open circuit m. a m. for measuring oxygen consumption and carbon dioxide production by collecting the expired gas over a known period of time and measuring its volume and composition. oral auditory m. an approach to the education of deaf children that emphasizes early auditory training, speech and speech reading, and early and consistent use of high quality amplification for residual hearing. SEE ALSO: manual visual m., combined methods, total communication. Orsi-Grocco m. palpatory percussion of the heart. Ouchterlony m. SYN: Ouchterlony test. Pachon m. cardiography carried out with the patient lying on the left side. paracelsian m. the treatment of disease using chemical agents only. parallax m. localization of a foreign body by observing the direction of its motion on a fluoroscopic screen while moving the x-ray tube or the screen. Pavlov m. the m. of studying conditioned reflex activity by the observation of a motor indicator, such as the salivary or electroencephalographic response. Politzer m. inflation of the eustachian tube and tympanum by forcing air into the nasal cavity at the instant the patient swallows. Porges m. a m. of destroying the capsule of bacteria by heating with N/4 hydrochloric acid and neutralizing with NaOH. Purmann m. treatment of aneurysm by extirpation of the sac. Quick m. SYN: prothrombin test. reference m. an analytical procedure sufficiently free of random or systematic error to make it useful for validating proposed new analytical procedures for the same analyte. Rehfuss m. m. of fractional measurement of gastric activity: a fine tube with fenestrated metal tip is passed into the stomach after a test meal, and small quantities (6 or 8 ml) of the stomach contents are removed at 15-min intervals and examined. rhythm m. a natural contraceptive m. that spaces human sexual intercourse to avoid the fertile period of the menstrual cycle. SYN: rhythm (2) . Rideal-Walker m. Rideal-Walker coefficient. Roux m. division of the mandible in the median line, to facilitate the operation of ablation of the tongue. Sanger m. the m. for the sequencing of DNA employing an enzyme that can polymerase DNA and labeled nucleotides. Scarpa m. cure of aneurysm by ligation of the artery at some distance above the sac. Schäfer m. an obsolete m. of resuscitation in cases of drowning or asphyxia; the patient is laid face downward and natural breathing is imitated by gentle intermittent pressure over the lower part of the thorax at the rate of about 15 times a minute. Schede m. filling of the defect in bone, after removal of a sequestrum or scraping away carious material, by allowing the cavity to fill with blood which may become organized (Schede clot). Schick m. SYN: Schick test. Schmidt-Thannhauser m. a m. for fractionation of nucleic acid, based upon the fact that RNA but not DNA is hydrolyzed to nucleotides by alkali; RNA can be hydrolyzed in about 2 h in 0.75 n NaOH, but 18 h and 0.3 n NaOH usually are used. Schweninger m. a m. suggested to reduce obesity by restricting intake of fluid. Shaffer-Hartmann m. an obsolete m. for the quantitative determination of glucose in biological fluids, based on the reduction of copper by the reducing group of the sugar. Somogyi m. Somogyi unit. split cast m. 1. a procedure for placing indexed casts on an articulator to facilitate their removal and replacement on the instrument; 2. the procedure of checking the ability of an articulator to receive or be adjusted to a maxillomandibular relation record. SYN: Needles split cast m.. Stas-Otto m. a m. of extraction of alkaloids from plants and animal bodies: the substance is digested in alcohol and tartaric acid, the fatty and resinous matters are precipitated with water, the fluid is made alkaline, and the alkaloids are extracted with ether or chloroform. Stewart-Hamilton m. SYN: Hamilton-Stewart m.. Thane m. a m. for indicating the position of the central sulcus (Rolando fissure) of the brain; the upper end of the sulcus corresponds to the midpoint of a line drawn from the glabella to the inion. Theden m. treatment of aneurysms or of large sanguineous effusions by compression of the entire limb with a roller bandage. Thezac-Porsmeur m. heat treatment of infected wounds by focusing of sun's rays on suppurating area by means of a lens mounted in a cylinder of canvas. thiochrome m. a m. for the determination of thiamin based upon the production of thiochrome when the vitamin is oxidized by alkaline ferricyanide to yield the fluorescent compound, thiochrome. twin m. a general means of genetic analysis that capitalizes on the fact that while twins have the same age and the same intrauterine environment, identical (monozygotic) twins have the same genotype but dizygotic twins are no more alike than sibs and may be of different sex. ultropaque m. a rapid m. for examining thick (1–3 mm) sections of fresh tissue with the ultramicroscope, making use of an objective built in an illuminator so that the light is reflected down upon the tissue. u-score m. an older, simpler, but somewhat less efficient m. of linkage analysis than that by maximum likelihood estimation. Wardrop m. treatment of aneurysm by ligation of the artery at some distance beyond the sac, leaving one or more branches of the artery between the sac and the ligature. Westergren m. a procedure for estimating the sedimentation rate of red blood cells in fluid blood by mixing venous blood with an aqueous solution of sodium citrate and allowing it to stand in an upright standard pipette (200 mm long) filled to the zero mark; the fall of the red blood cells, in millimeters, is then observed in 1 hr; the normal rate for men is 0–15 mm (average, 4 mm), and for women 0–20 mm (average, 5 mm). Wheeler m. a surgical procedure for correction of cicatricial ectropion. Wilson m. a simple saline flotation m. for concentrating helminth eggs in the feces. See flotation m.. SYN: Hung m.. zinc sulfate flotation centrifugation m. a flotation m. in which the fecal specimen is suspended in tap water, strained through wet gauze, centrifuged, resuspended in tap water, washed and recentrifuged several times, and then suspended in 33% solution of zinc sulfate and centrifuged at top speed for 45–60 sec; a bacteriologic loop may be used to pick up the surface layer, which contains protozoan cysts and helminth eggs.

methodism (meth′od-izm)
SYN: solidism.

methodology (meth′u-dol-o-je)
The scientific study or logical analysis of methods.

methohexital sodium (meth-o-heks′i-tawl)
An ultra-short-acting barbiturate used intravenously for induction and for general anesthesia of short duration.

methophenazine (me-tho-fen′a-zen)
An antipsychotic.

methopholine (me-tho-fo′len)
An analgesic.

methopterin (meth-op′ter-in)
A folic acid antagonist.

methorphinan (meth-or′fi-nan)
See dextromethorphan hydrobromide, levorphanol tartrate.

methoserpidine (meth-o-ser′pi-den)
An antihypertensive agent similar in its actions to reserpine.

methotrexate (meth-o-trek′sat)
A folic acid antagonist used as an antineoplastic agent; used to treat psoriasis and rheumatoid arthritis. SYN: amethopterin.

methotrimeprazine (meth′o-tri-mep′ra-zen)
A phenothiazine analgesic.

methoxamine hydrochloride (me-thok′sa-men)
A sympathomimetic amine.

methoxsalen (me-thok′sa-len)
A methoxypsoralen derivative that increases melanin production in the skin when exposed to ultraviolet light; used orally and topically in the treatment of idiopathic vitiligo, and also as a suntan accelerator and sun protectant.

Chemical prefix denoting substitution of a methoxyl group.

4-methoxybenzoic acid (meth-ok′se-ben-zo′ik)
SYN: anisic acid.

methoxychlor (me-thok′se-klor)
An insecticide resembling DDT; ectoparasiticide.

methoxyflurane (me-thok-se-floor′an)
A potent inhalation anesthetic no longer in use because of high-output renal failure caused by increased plasma concentrations of inorganic fluoride, a metabolic breakdown product of m..

3-methoxy-4-hydroxymandelic acid
See vanillylmandelic acid.

5-methoxyindole-3-acetate (meth-oks′e-in-dol)
An intermediate of tryptophan and serotonin degradation; excreted as conjugates.

methoxyl (me-thok′sil)
The group, –OCH3.

methoxyphenamine hydrochloride (me-thok-se-fen′a-men)
A sympathomimetic amine.

5-methoxytryptamine (meth-oks′e-trip-ta-men)
An intermediate in the degradation of l-tryptophan and serotonin.

methscopolamine bromide (meth-sko-pol′a-men)
A parasympatholytic drug similar to atropine; the methyl nitrate has the same action and uses.

methsuximide (meth-suk′si-mid)
An antiepileptic effective against petit mal and psychomotor epilepsy; similar to ethosuximide.

methyclothiazide (meth′i-klo-thi′a-zid)
An orally effective diuretic and antihypertensive agent of the thiazide group.

methyl (Me) (meth′il)
The moiety, &cbond;CH3. [G. methy, wine, + hyle, wood] active m. a m. group attached to a quaternary ammonium ion or a tertiary sulfonium ion that can take part in transmethylation reactions; e.g., m. groups in choline and in S-adenosyl-l-methionine, which are thus m. donors. m. aldehyde SYN: formaldehyde. angular m. a m. group attached to carbon 10 (between rings A and B) or to carbon 13 (between rings C and D) of the steroid nucleus. m. chloride SYN: chloromethane. m. cysteine hydrochloride the m. ester of cysteine hydrochloride; a mucolytic agent. m. hydroxybenzoate SYN: methylparaben. m. isobutyl ketone in high concentrations it has narcotic action; in relatively low concentrations it may be irritating to the eyes and mucous membranes. m. methacrylate a thermoplastic material used for denture bases and as an embedding material for electron microscopy. m. nicotinate nicotinic acid m. ester, used as rubefacient.

2-methylacetoacetyl-CoA thiolase
An enzyme that is part of the l-isoleucine degradation pathway; it catalyzes the conversion of 2-methylacetoacetyl-CoA to acetyl-CoA and propionyl-CoA. A deficiency of this enzyme leads to an accumulation of 2-methylacetoacetyl-CoA, causing episodes of severe metabolic acidosis and ketosis.

methylacrylic acid (meth′il-a-kril′ik)
SYN: methacrylic acid.

methylamphetamine hydrochloride (meth′il-am-fet′a-men)
SYN: methamphetamine hydrochloride.

methylate (meth′i-lat)
1. To mix with methanol. 2. To introduce a methyl group. 3. A compound in which a metal ion methyl replaces the alcoholic hydrogen of alcohol.

methylation (meth-i-la′shun)
Addition of methyl groups; in histochemistry, used to esterify carboxyl groups and remove sulfate groups by treating tissue sections with hot methanol in the presence of hydrochloric acid; the net effect being to reduce tissue basophilia and abolish metachromasia. restriction m. the enzymatic addition of methyl groups to selected adenine and cytosine residues to protect from hydrolysis by certain restriction enzymes.

methylatropine bromide (meth-il-at′ro-pen, -pin)
A quaternary derivative of atropine that is less lipid soluble and hence produces fewer central nervous system actions; a cycloplegic. SYN: atropine methylbromide.

methylbenzene (meth-il-ben′zen)
SYN: toluene.

methylbenzethonium chloride (meth′il-ben-ze-tho′ne-um)
A quaternary ammonium compound having a surface action like that of other cationic detergents; generally germicidal and bacteriostatic; used to rinse infant diapers and bed linen in the prevention of ammonia dermatitis.

methyl blue [C.I. 42780]
A sulfonated triphenylrosaniline dye used as a stain for cytoplasm, collagen, and Negri bodies, and as an antiseptic.

methyl bromide
Used in ionization chambers; for degreasing wool; extracting oils from nuts, seeds, flowers; used as an insect fumigant for mills, warehouses, vaults, ships, freight cars; also as a soil fumigant.

A nitrosourea antineoplastic agent resembling carmustine (BCNU) and lomustine (CCNU). SYN: semustine.

methylcellulose (meth-il-sel′u-los)
A methyl ester of cellulose that forms a colorless viscous liquid when dissolved in water, alcohol, or ether; used to increase bulk of the intestinal contents, to relieve constipation, or of the gastric contents, to reduce appetite in obesity; also used dissolved in water as a spray to cover burned areas and as a suspending agent in pharmaceuticals and foods.


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