Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «M»:
Meter, pH: See: pH meter....
Metered dose inhaler
Metered dose inhaler: See: Metered-dose inhaler....
Methadone: A synthetic opiate. The most common
medical use for methadone is as a legal substitute for
heroin in treatment programs for drug addiction. It is usually
administered to participating addicts daily in the form of a green, tasteless liquid at a drug treatment clinic. See also: Methadone...
Methadone treatment program
Methadone treatment program: A program for opiate addicts, usually conducted in an outpatient setting. These programs use a long-acting synthetic opiate medication, usually methadone or LAAM, administered orally for a sustained period at a dosage sufficient to prevent opiate withdrawal, block the ef...
Methanococcus jannaschii: A microbe that produces methane, an important energy source, and contains enzymes that withstand high temperatures and pressures. The genome of Methanococcus jannaschii has been completely sequenced....
Methemoglobin: A particular type of hemoglobin that is altered so that it 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, its wholesale replacement by methemoglobin can cause cyanosis (a slate gray-blu...
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, its replacement by methemoglobin can cause cyanosis (a slate gra...
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 Rarely used now, methicillin has been largely superceded by Vancomycin. Over the past 50...
Methicillin-resistant staphylococcus aureus
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 very sick, and those with an open ...
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....
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 pregnant or using a barrier method (such as a condom, the diaphragm...
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 abnormally rapid cell growth such as certain tumors and psoriasis. Tumors treated with MT...
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 the atmosphere. Among agricultural workers who apply pesticides, th...
Methyl-CpG-binding protein-2 (MECP2)
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 females.
After normal development up to the ...
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 methyl group to a cytosine residue to convert it to 5-methylcytosine....