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(nī′trŭs) [Gr. nitron, salt] Containing nitrogen in its lowest valency.

nitrous acid

HNO2; a chemical reagent used in biological laboratories.

nitrous oxide

N2O, a flammable, anesthetic and analgesic gas, used in both general and outpatient dental anesthesia. Its use has been associated with miscarriage, organ injuries, and dependence and abuse, although the data linking nitrous oxide to these problems are controversial. The informal name of nitrous oxide is laughing gas. SYN: dinitrogen monoxide.

 Nitrous oxide has little or no effect on body temperature, metabolism, blood pressure, volume, or composition, or on the genitourinary system. Diaphoresis, increased muscle tone, or both may occur with induction of anesthesia with nitrous oxide.

 Asphyxiation may occur if it is not administered properly. Prolonged administration of nitrous oxide will cause depression of bone marrow.

 SYMPTOMS: Signs of deep nitrous oxide anesthesia include a slight increase in respirations and some dyspnea. The pupils become fixed and dilated, and there is muscular rigidity and cyanosis that increases to a grayish pallor.

 TREATMENT: Patients suffering from an overdose should be oxygenated and ventilated.

exhaled n.o. The concentration of nitrous oxide (N2O) in expired air.

NK cell

natural killer cell.


National Library of Medicine.


National League for Nursing.


natural language processing.




N-methyl-D-aspartate, a neurotransmitter that increases the uptake of calcium ions by neurons and excites (stimulates) those cells.


National Marrow Donor Program. Website:


Nursing Minimum Data Set.


necrolytic migratory erythema; new molecular entity.


neuromyelitis optica.

NMR spectroscopy

nuclear magnetic resonance spectroscopy.


neuroleptic malignant syndrome.


National Multiple Sclerosis Society.

N, N-diethyl-m-toluamide

(en′en′dī-eth′ĭl em-to-lū′ă-mīd″) DEET.

N, N-dimethyltryptamine

(dī-mĕth″ĭl-trĭp′tă-mĭn) [dimethyl + tryptamine] ABBR: DMT. A hallucinogenic compound found in ayahuasca, a woody vine, Banisteriopsis caapi, and in other tropical plants. It has also been manufactured synthetically.


nonnucleoside analog reverse transcriptase inhibitor.


nitrogen monoxide.

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