Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «N»:
Nitrogen: Element number 7, a colorless, odorless, tasteless gas that is biologically important. Nitrogen is a constituent of protein and nucleic acids and is present in all living cells. Nitrogen does not support respiration and is fatal if breathed alone, because of the lack of oxygen. Nitrogen is...
Nitrogen narcosis: A condition similar to intoxication with alcohol with euphoria, loss of balance and manual dexterity, disorientation and impaired reasoning that occurs in divers below 100 feet (30 meters) who breath compressed air because of the high nitrogen content of air. Nitrogen narcosis is ...
Nitrogen, liquid: See: Liquid nitrogen....
Nitrogenous base: A molecule that contains nitrogen
has the chemical properties of a base. The nitrogenous bases in DNA
are adenine (A),
guanine (G), thymine (T), and cytosine (C). The nitrogenous bases in
RNA are the same with
one exception: adenine (A), guanine (G), uracil (U), and cytosine...
Nitrosoureas: A group of cancer drugs called alkylating agents because they act by the process of alkylation to inhibit DNA repair. The nitrosoureas can cross the blood-brain barrier and are used to treat brain tumors. The nitrosoureas include carmustine (BCNU), lomustine (CCNU) and semustine....
Nitrous oxide (laughing gas)
Nitrous oxide (laughing gas): A gas that can cause general anesthesia. Nitrous oxide is sometimes given in the company of other anesthetic agents but it is not used today as the only anesthetic agent because the concentration of nitrous oxide needed to produce anesthesia is close to the concentratio...
NK cell: See Natural killer cell....
NLD: Necrobiosis lipoidica diabeticorum....
NLM (National Library of Medicine)
NLM (National Library of Medicine): The world's largest
medical library, the U.S. National Library of Medicine (NLM) is part
of the National Institutes of Health (NIH). The NLM has as its
mission to collect, organize, and make available biomedical science
information to investigators, educators...
NMR: Nuclear Magnetic Resonance. An imaging technique that does
not use radiation. ...
No show: Term used in the US for a patient who missed an appointment. (In the UK, a patient who failed an appointment "did not attend." This is abbreviated DNA, not to be confused with the genetic material.)...
Nocardia infection: Also called nocardiosis, infection with bacteria called Nocardia which tend to strike the lungs, brain and skin, particularly in people with an impaired immune system. The majority (about 80%) of cases of nocardiosis involves lung infection, brain abscess, or disseminated (widesp...
Nocardiosis: An infection with bacteria called Nocardia which tend to strike the lungs, brain and skin, particularly in people with an impaired immune system. The majority (about 80%) of cases of nocardiosis involves lung infection, brain abscess, or disseminated (widespread) disease from Nocardia. ...
Nocebo: A negative placebo effect as, for example, when patients taking medications experience adverse side effects unrelated to the specific pharmacological action of the drug. The nocebo effect is associated with the person's prior expectations of adverse effects from treatment as well as with con...
Nocturia: Excessive urinating at night. People with nocturia must get up, often two times or more, during the night to urinate. Normally, urine is more concentrated at night and is produced in lower amounts, so that uninterrupted sleep is possible. However, excess urine production at night can occur...