Medical terms - Letter M
1,075 terms start with the letter M.
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Methemoglobinemia
The presence in the blood of methemoglobin, a form of hemoglobin that is useless for carrying oxygen and delivering it to tissues throughout the human body. Since hemoglobin is the key carrier of oxygen in the blood…
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Methicillin
A semisynthetic penicillin-related antibiotic, also known as Staphcillin, that once was effective against staphylococci (staph) resistant to penicillin because they produce the enzyme penicillinase. Rarely used now…
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Methicillin-resistant staphylococcus aureus
Staphylococcus aureus (a type of staph bacteria) resistant to the antibiotic methicillin. Abbreviated MRSA. MRSA first cropped up among persons in hospitals and other health facilities, especially among the elderly, the…
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Methionine
An amino acid, one of the 20 building blocks of protein. A dietary essential amino acid, methionine provides methyl groups and sulfur for normal metabolism. Symbol: Met
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Method, rhythm
Also known as fertility awareness, natural family planning, and periodic abstinence, this approach to contraception entails not having sexual intercourse on the days of a woman's menstrual cycle when she could become…
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Methotrexate
Methotrexate: A drug that acts as an antimetabolite and specifically as a folic acid antagonist that inhibits the synthesis of DNA, RNA, and protein. Methotrexate (MTX) is used to treat diseases associated with…
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Methyl bromide
A fumigant gas that is an effective pesticide. Methyl bromide has been used to treat the soil, grain bins, and many agricultural products. Because it contains bromine, it depletes stratospheric ozone when released to…
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Methyl-CpG-binding protein-2 (MECP2)
An enzyme which, when mutated, results in RTT (Rett syndrome), a genetic disease that is a uniform and striking, progressive neurologic developmental disorder and one of the most common causes of mental retardation in…
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Methylation
1. In chemistry, the addition of a methyl group to a molecule. 2. On a protein level, the addition of a methyl group or groups to the amino acid arginine or lysine in a protein. 3. On a DNA level, the addition of a…
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Methylenedioxymethamphetamine
3-4 methylenedioxymethamphetamine (MDMA), best known on the street as 'Ecstacy.' An illicit drug, considered a recreational or party drug. It acts as both a stimulant and a hallucinogen. Ecstasy achieves its high by…
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Methylmalonicaciduria
An inherited metabolic (biochemical) disease that causes young children to become mentally retarded. The defect in some (but not all) of these children has to do with an inability to use the vitamin B12 they ingest. If…
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Methylmercury
An organic form of mercury that is highly toxic and is the main culprit in mercury poisoning. Methylmercury is easily absorbed into the living tissue of aquatic organisms, is not easily eliminated, and therefore…
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Metrorrhagia
Uterine bleeding at irregular intervals, particularly between the expected menstrual periods. Metrorrhagia may be a sign of an underlying disorder, such as hormone imbalance, endometriosis, uterine fibroids or, rarely…
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Meuse fever
Fever: Named for the Meuse River area, one of the great battlegrounds of World War I. Also known as trench fever. Meuse or trench fever is a disease borne by body lice that was first recognized in the trenches of World…
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Mg
Abbreviation for milligram, a unit of measurement of mass in the metric system equal to a thousandth of a gram. A gram is equal to the mass of one milliliter, one thousandth of a liter, of water at 4 degrees C. MG (in…
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MG (myasthenia gravis)
Myasthenia gravis (MG): An autoimmune neuromuscular disorder characterized by fatigue and exhaustion of muscles. It is caused by a mistaken immune response to the nicotinic acetylcholine receptors (AChR), which are…
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MGy
Abbreviation for milligray
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MHC
Major histocompatibility complex
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MI
A poisonous vapor or mist believed to be made up of particles from decomposing material that could cause disease and could be identified by its foul smell. The miasma theory of disease originated in the Middle Ages and…
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Miasma
A poisonous vapor or mist believed to be made up of particles from decomposing material that could cause disease and could be identified by its foul smell. The miasma theory of disease originated in the Middle Ages and…
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Miasmic
Pertaining to a miasma, a poisonous vapor or mist that was once widely believed to be made up of particles from decomposing material which could cause disease and which could be identified by its foul smell. See: Miasma
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MIC-1
Macrophage inhibitory cytokine 1. A divergent member of the transforming growth factor beta superfamily. MIC-1 is produced in the placenta. There are detectable levels of MIC-1 in the blood of the mother during…
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Michael Stuart Brown
See: Brown, Michael Stuart
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Micro-
Prefix derived from the Greek 'mikros' meaning small. Examples of the many biomedical terms containing 'micro-' include the following:microangiopathy,microcephaly,microcystic (as in microcystic corneal…
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Micro-RNA
A tiny piece of RNA, about 21 to 23 bases in length, that binds to matching pieces of messenger RNA to make it double-stranded and decrease the production of the corresponding protein. Micro-RNA's were first discovered…
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Microabscess
A tiny abscess. A small accumulation of pus
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Microalbuminuria
1. Generally, a subtle increase in the urinary excretion of the protein albumin that cannot be detected by a conventional assay. In diabetes, microalbuminuria is an early sign of diabetic kidney disease.2. Specifically…
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Microangiopathy
Angiopathy means disease of the blood vessels (arteries, veins, and capillaries). There are two types of angiopathy: macroangiopathy and microangiopathy. With macroangiopathy, fat and blood clots build up in the large…
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Microarray
A tool used to sift through and analyze the information contained within a genome. A microarray consists of different nucleic acid probes that are chemically attached to a substrate, which can be a microchip, a glass…
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Microbe
A very tiny form of life -- microbes include bacteria, fungi, and protozoan parasites -- best visualized under a microscope. The Microbe is so very smallYou cannot make him out at all,But many sanguine people hopeTo see…
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Microbicide
An agent that kills microbes, minute forms of life (e.g. bacteria, fungi, and protozoal parasites), some capable of causing human disease. From microbe + the Latin 'caedo,' to kill.
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Microcephalin
See: Microcephalin 1
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Microcephalin 1
Mutation of this gene is responsible for an autosomal recessive form of primary microcephaly with no other malformations. Microcephalin 1 (MCPH1) is expressed in fetal brain in the developing forebrain and the walls of…
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Microcephaly
Microcephaly: An abnormally small head due to failure of brain growth. In precise terms, microcephaly is a head circumference that is more than 2 standard deviations below the normal mean for age, sex, race, and…
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Microchimerism
The presence of two genetically distinct and separately derived populations of cells, one population being at a low concentration, in the same individual or an organ such as the bone marrow. Microchimerism may be due to…
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Microcystic corneal dystrophy
A disorder in which the cornea (the normally clear front window of the eye) shows dots (or microcysts), geographic map-like lines, and grayish fingerprint lines on examination with a slit-lamp, a device that focuses a…
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Microcytic
1. Any abnormally small cell. The opposite is macrocytic, an abnormally large cell. 2. An abnormally small red blood cell. Iron deficiency is a prominent cause of microcytic anemia
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Microdeletion
The loss of a tiny piece of a chromosome, a piece so small its absence is not apparent on ordinary examination (using a regular light microscope to look at chromosomes prepared in the usual fashion). The detection of…
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Microdosimetry
A technique for measuring the microscopic distribution of energy, useful with different types of radiation. Microdosimetry provides the scientific underpinnings for the measurement of radiation. It is vitally important…
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Microduplication
The gain of a tiny piece of a chromosome, a piece so small its presence is not apparent on ordinary examination (using a regular light microscope to look at chromosomes prepared in the usual fashion). The detection of…
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Microduplication 22q11.2 syndrome
A syndrome due to duplication of a tiny part of chromosome band 22q11.2. Features of the syndrome include the appearance of widely spaced eyes and superior placement of eyebrows; downslanting palpebral fissures (eye…
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Microembolus
An embolus of microscopic size. For example, a tiny blood clot or little clump of bacteria. Like any embolus, it travels through the bloodstream, lodges in a blood vessel and blocks it
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Microhematuria
Hematuria means blood in the urine and microhematuria refers to hematuria that is visible only under a microscope. There is so little blood that it cannot be seen without magnification. Microhematuria is in contrast to…
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Microorchidism
Abnormally small testes. To determine if the testes are too small, a device called an orchidometer is used that permits the testes to be compared to a series of plastic ovals (like miniature American footballs) of…
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Micropenis
An abnormally small penis. In medical practice, the dimension of the penis that is measured is the length. This measurement is taken along the upper surface of the shaft of the penis to the tip, using a measuring tape…
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Microphallus
An abnormally small penis. Also called micropenis. In medical practice, the dimension of the penis that is measured is the length. The measurement is taken along the upper surface of the shaft of the penis to the tip…
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Microphthalmia
An abnormally small eye, a congenital malformation (birth defect) of the globe. The related term 'anophthalmia' means no eye and refers to absence of the globe and ocular tissue from the orbit. Microphthalmia may…
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Microphthalmia syndrome, Lenz
Tattooing.
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Micropigmentation
Tattooing
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Microscope
An optical instrument that augments the power of the eye to see small objects. The name microscope was coined by Johannes Faber (1574-1629) who in 1628 borrowed from the Greek to combined micro-, small with skopein, to…