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Medical Dictionary


mesomorph (mez′o-morf)
A constitutional body type or build (biotype or somatotype) in which tissues that originate from the mesoderm prevail; from the morphological standpoint, there is a balance between trunk and limbs. SEE ALSO: hypermorph, hypomorph, ectomorph, endomorph. SYN: mediotype. [meso- + G. morphe, form]

mesomorphic (mez-o-morf′ik)
Relating to mesomorphs.

meson (mez′on, me′zon, mes′on)
An elementary particle having a rest mass intermediate in value between the mass of an electron and that of a proton. [G. neuter of mesos, middle]

mesonephric (mez-o-nef′rik)
Relating to the mesonephros.

mesonephroi (mez′o-nef′roy)
Plural of mesonephros.

mesonephroma (mez′o-ne-fro′ma)
Obsolete term for a relatively rare malignant neoplasm of the ovary and corpus uteri, thought to originate in mesonephric structures that become misplaced in ovarian tissue during embryonic development; characterized by a tubular pattern, with focal proliferation of epithelial cells with clear cytoplasm or of the hob-nail type; so-called glomeruloid structures are reported, i.e., small convolutions or tufts of tiny tubate formations with capillaries extending into the spaces. SYN: clear cell carcinoma, mesonephric adenocarcinoma, mesonephroid tumor, wolffian duct carcinoma. [mesonephros + -oma, tumor]

mesonephros, pl .mesonephroi (mez′o-nef′ros, -roy)
One of three excretory organs appearing in the evolution of vertebrates; in life forms with a metanephros, the m. is located between the regressing pronephros and the metanephros, cephalic to the latter. In young mammalian embryos, the m. is well developed and briefly functional until establishment of the metanephros, the definitive kidney; in older embryos, the m. undergoes regression as an excretory organ, but its duct system is retained in the male as the epididymis and ductus deferens. SYN: middle kidney, wolffian body. [meso- + G. nephros, kidney]

mesoneuritis (mez′o-noo-ri′tis)
Inflammation of a nerve or of its connective tissue without involvement of its sheath. nodular m. inflammation of the connective tissue beneath the nerve sheath, with the formation of circumscribed fibrous thickenings.

meso-ontomorph (mez-o-on′to-morf)
A broad, stocky individual. [meso- + G. on, being, + morphe, form]

mesopexy (mez′o-pek-se)
SYN: mesenteriopexy.

mesophil, mesophile (mez′o-fil, -fil)
A microorganism with an optimum temperature between 25°C and 40°C, but growing within the limits of 10°C and 45°C. [meso- + G. philos, fond]

mesophilic (mez′o-fil′ik)
Pertaining to a mesophil.

mesophlebitis (mez′o-fle-bi′tis)
Inflammation of the middle coat of a vein. [meso- + phlebitis]

mesophragma (mez-o-frag′ma)
SYN: M line. [meso- + G. phragma, a fence]

mesophryon (mez-of′ri-on)
SYN: glabella (2) . [meso- + Gr. ophrys, eyebrow]

mesopic (me-zo′pik)
Pertaining to illumination between the photopic and scotopic ranges. [meso- + G. opsis, vision]

mesopneumonium (mez′o-noo-mo′ne-um)
The reflection of pleura surrounding the root of the lung (including the pulmonary ligament inferiorly) as parietal pleura becomes continuous with the visceral pleura of the lung. SYN: mesentery of lung, pleural isthmus.

mesoporphyrins (mez-o-por′fi-rinz)
Porphyrin compounds resembling the protoporphyrins except that the vinyl side chains of the latter are reduced to ethyl side chains; e.g., mesobilane.

SYN: rectosacral fascia.

mesoprosopic (mez′o-pro-sop′ik)
Having a face of moderate width, i.e., with a facial index of about 90. [meso- + G. prosopon, face]

mesopulmonum (mez-o-pul′mon-um)
The mesentery of the embryonic lung. [meso- + L. pulmo, lung]

mesorchial (mez-or′ke-al)
Relating to the mesorchium.

mesorchium (mez-or′ke-um)
1. In the fetus, a fold of tunica vaginalis testis supporting the mesonephros and the developing testis. 2. In the adult, a fold of tunica vaginalis testis between the testis and epididymis. [meso- + G. orchis, testis]

mesorectum (mez′o-rek′tum)
The peritoneal investment of the rectum, covering the upper part only.

mesoridazine besylate (mez-o-rid′a-zen)
A biotransformation product of thioridazine; an antipsychotic.

mesorrhaphy (mez-or′a-fe)
SYN: mesenteriorrhaphy.

mesorrhine (mez′o-rin)
Having a nose of moderate width. Denoting a skull with a nasal index from 47 to 51 (Frankfort agreement) or 48 to 53 (Broca). [meso- + G. rhis (rhin-), nose]

mesosalpinx (mez′o-sal′pinks) [TA]
The part of the broad ligament investing the uterine (fallopian) tube. [meso- + G. salpinx, trumpet]

mesoscope (mez′o-skop)
An instrument for viewing objects that are larger than microscopic but cannot be seen distinctly with the naked eye. [meso- + G. skopeo, to view]

mesoseme (mez′o-sem)
Denoting an orbital aperture with an index between 84 and 89; characteristic of the white race. [meso- + G. sema, sign]

mesosigmoid (mez′o-sig′moyd)
Sigmoid mesocolon. See mesocolon.

mesosigmoiditis (mes′o-sig-moy-di′tis)
Inflammation of the mesosigmoid.

mesosigmoidopexy (mez-o-sig-moy′do-pek-se)
Surgical fixation of the mesosigmoid.

mesosomatous (mez′o-so′ma-tus)
Denoting a person of medium height.

mesosome (mes′osom)
A convoluted membranous body formed by involution of the plasma membranes of certain bacteria; it functions in cellular respiration and septum formation. [meso + G. soma, body]

mesosomia (mez′o-so′me-a)
Medium height. [meso- + G. soma, body]

mesostenium (mez′o-ste′ne-um)
SYN: mesentery (2) .

mesosternum (mez′o-ster′num)
SYN: body of sternum. [meso- + G. sternon, chest]

mesosystolic (mez′o-sis-tol′ik)

mesotarsal (mez′o-tar′sal)
SYN: midtarsal.

mesotendineum (mez′o-ten-din′e-um) [TA]
SYN: mesotendon.

mesotendon (mez′o-ten′don) [TA]
The synovial layers that pass from a tendon to the wall of a tendon sheath in certain places where tendons lie within osteofibrous canals. In most instances, the m. degenerates, leaving only the vinculae. SYN: mesotendineum [TA] .

mesothelia (mez-o-the′le-a)
Plural of mesothelium.

mesothelial (mez-o-the′le-al)
Relating to the mesothelium.

mesothelioma (mez′o-the-le-o′ma)
A rare neoplasm derived from the lining cells of the pleura and peritoneum which grows as a thick sheet covering the viscera, and is composed of spindle cells or fibrous tissue which may enclose glandlike spaces lined by cuboidal cells. [mesothelium + G. -oma, tumor] benign m. SYN: solitary fibrous tumor. benign m. of genital tract SYN: adenomatoid tumor.

mesothelium, pl .mesothelia (mez-o-the′le-um, -le-a)
A single layer of flattened cells forming an epithelium that lines serous cavities; e.g., peritoneum, pleura, pericardium. [meso- + epithelium]

mesothorium (mez′o-thor′e-um)
The first two disintegration products of thorium; m. 1 is 228Ra, a beta emitter with a half-life of 6.7 years, decaying into m. 2, which is 228Ac, a beta emitter with a half-life of 6.13 hr, which disintegrates to radiothorium (228Th).

mesotropic (mez′o-trop′ik)
Turned toward the median plane. [meso- + G. trope, a turning]

mesotympanum (mez-o-tim′pan-um)
The portion of the middle ear medial to the tympanic membrane.

mesouranic (mes′o-u-ran′ik)
Having a palatal index between 110 and 115. SYN: mesuranic. [meso- + G. ouranos, palate]

mesovarium, pl .mesovaria (mez′o-va′re-um, -a) [TA]
Portion of the broad ligament of the uterus that reflects onto and suspends the ovary. SYN: mesoarium. [meso- + L. ovarium, ovary]

Mesozoa (mez-o-zo′a)
A small phylum of about 50 species of parasites of marine invertebrates with complex life cycles. M. are classified with the Metazoa, but they are regarded by some observers as intermediate between unicellular and multicellular animals; others consider them a degenerate group of flatworms. M. are divided into two very distinct orders, the Orthonectida and Dicyemida; the latter are nephridial parasites of squids, octopods, and cuttlefish. [meso- + G. zoon, animal]

messenger (mes′en-jer)
1. That which carries a message. 2. Having message-carrying properties. first m. a hormone that binds to a receptor on the surface cell and, in so doing, communicates with intracellular metabolic processes. second m. an intermediary molecule that is generated as a consequence of hormone-receptor interaction; e.g., see adenosine 3′,5′-cyclic monophosphate, guanosine 3′,5′-cyclic monophosphate, calcium, inositide.

messenger RNA (mRNA)
See under ribonucleic acid.

mestanolone (mes-tan′o-lon)
An androgenic steroid with anabolic properties.

mestenediol (mes-ten′di-ol)
SYN: methandriol.

mestranol (mes′tra-nol)
The 3-methyl ether of ethynyl estradiol; an estrogen used in many oral contraceptive preparations.

mesulphen (me-sul′fen)
A topical scabicide with antipruritic properties.

mesuranic (mez′u-ran′ik)
SYN: mesouranic.

Abbreviation for metabolic equivalent.

Symbol for methionine or methionyl.

In medicine and biology, a prefix denoting the concept of after, subsequent to, behind, or hindmost. Cf.:post-. [G. after, between, over]

1. In chemistry, an italicized prefix denoting joint, action sharing. 2. (m-) In chemistry, an italicized prefix denoting a compound formed by two substitutions in the benzene ring separated by one carbon atom, i.e., linked to the first and third, second and fourth, etc., carbon atoms of the ring. For terms beginning with m., or m-, see the specific name. [G. after, between, over]

metaanalysis (met′a-a-nal′i-sis)
The process of using statistical methods to combine the results of different studies; systematic, organized, and structured evaluation of a problem using information, commonly in the form of statistical tables, from a number of different studies of a problem.

metabasis (me-tab′a-sis)
Rarely used term for a change of any kind in symptoms or course of a disease. [G. a passing over, change, fr. metabaino, to pass over]

metabiosis (met′a-bi-o′sis)
Dependence of one organism on another for its existence. SEE ALSO: commensalism, mutualism, parasitism. [meta- + G. biosis, way of life]

metabolic (met-a-bol′ik)
Relating to metabolism.

metabolimeter (met′a-bo-lim′e-ter)
A modified calorimeter for measuring the rate of basal metabolism.

metabolin (me-tab′o-lin)
SYN: metabolite.

metabolism (me-tab′o-lizm)
1. The sum of the chemical and physical changes occurring in tissue, consisting of anabolism, those reactions that convert small molecules into large, and catabolism, those reactions that convert large molecules into small, including both endogenous large molecules as well as biodegradation of xenobiotics. 2. Often incorrectly used as a synonym for either anabolism or catabolism. [G. metabole, change] basal m. oxygen utilization of an individual during minimal physiologic activity while awake; an obsolete test determined by measuring oxygen consumption of a fasting subject at complete bodily and mental rest and a room temperature of 20°C. SYN: basal metabolic rate. carbohydrate m. oxidation, breakdown, and synthesis of carbohydrates in the tissues. electrolyte m. the chemical changes that various essential minerals ( e.g., sodium, potassium, calcium, magnesium) undergo in the tissues. energy m. those metabolic reactions whose role is to release or to provide energy. fat m. oxidation, decomposition, and synthesis of fats in the tissues. first-pass m. the intestinal and hepatic degradation or alteration of a drug or substance taken by mouth, after absorption, removing some of the active substance from the blood before it enters the general circulation. SYN: first-pass effect. inborn error of m. a genetic biochemical disorder of a specific enzyme that forms a metabolic block, e.g., phenylketonuria. intermediary m. the sum of all metabolic reactions between uptake of foodstuffs and formation of excretory products. oxidative m. SYN: ventilation (2) . primary m. metabolic processes central to most cells; e.g., biosynthesis of macromolecules, energy production, turnover, etc. protein m. decomposition and synthesis of protein in the tissues. SYN: proteometabolism. respiratory m. the exchange of respiratory gases in the lungs, oxidation of foodstuffs in the tissues, and production of carbon dioxide and water. secondary m. metabolic processes in which substances (such as pigments, alkaloids, terpenes, etc.) are only synthesized in certain types of tissues or cells or are only synthesized under certain conditions.

metabolite (me-tab′o-lit)
Any product or substrate (foodstuff, intermediate, waste product) of metabolism, especially of catabolism. SYN: metabolin. primary m. a m. synthesized in a step in primary metabolism. secondary m. a m. synthesized in a step in secondary metabolism.


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