Medical Dictionary

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An alphabetical listing of General terms and items.

N-ACETYL-CYSTEINE (NAC)   Dico Tools
A form of the animo acid cysteine that is available as a nutritional supplement. NAC is used to prevent liver damage due to acetaminophen overdose.


NAC   Dico Tools
See n-acetyl-cysteine.


NAIVE   Dico Tools
Inexperienced. Often used to describe an individual who has never taken a certain drug, or to an undifferentiated immune system cell.


NARCOTIC   Dico Tools
See opiate.


Nares   Dico Tools
Plural, Latin naris = nostril.


Naris   Dico Tools
Latin = nostril, plural - nares.


Nasal   Dico Tools
Adjective, Latin nasus = nose; hence, pertaining to the nose.


Natal   Dico Tools
Adjective, Latin natus = born; hence, relating to birth.


NATIONAL INSTITUTES OF HEALTH (NIH)   Dico Tools
A large biomedical research organization that is part of the U.S. Public Health Service. The NIH includes several institutes, centers, and divisions. The National Institute of Allergy and Infectious Diseases (NIAID) and the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) conduct research on viral hepatitis.


NATURAL KILLER (NK) CELL   Dico Tools
A type of white blood cell that attacks and kills tumor cells and cells infected with microorganisms.


NATUROPATHY   Dico Tools
A system of natural healing based on the philosophy that the body has the ability to cure itself.


NAUSEA   Dico Tools
Stomach distress characterized by an aversion to food and an urge to vomit.


Navicular   Dico Tools
Adjective, Latin navicula = a little ship (cf. naval); hence, the tarsal bone which is concave posteriorly, resembling a boat.


NDA   Dico Tools
See new drug application.


Nebulizer   Dico Tools
A device that takes a liquid form of medicine and converts it into a mist to be breathed in (see Asthma).


NECROINFLAMMATION   Dico Tools
Tissue inflammation and death.


NECROSIS   Dico Tools
Cell or tissue death.


Neo-   Dico Tools
Greek prefix - neos = new.


Neoadjuvant Therapy   Dico Tools
Therapy with anticancer drugs or radiation given before surgery in order to shrink a tumor (see Breast Cancer).


Neonatal   Dico Tools
Adjective, Greek neos = new, and Latin natos = born; hence, new-born.


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NEONATE (adjective NEONATAL)   Dico Tools
A newborn, especially within the first days or weeks after birth.


Neopallium   Dico Tools
Greek neos = new, and Latin pallium = cloak; hence, the cerebral cortex which developed more recently than the archipallium or olfactory cortex.


NEOPLASM (NEOPLASIA)   Dico Tools
A tumor or growth; tissue that develops abnormally or cells that proliferate more rapidly than normal. A benign neoplasm (e.g., a wart) is localized and does not spread to other tissues; a malignant neoplasm (cancer) can spread to other parts of the body.


NEPHROLITHIASIS   Dico Tools
See kidney stone.


NEPHROTOXICITY   Dico Tools
The property of being poisonous or harmful to the kidneys.


Nerve   Dico Tools
Latin nervus = tendon; later reserved for a peripheral bundle of fibres which conduct impulses from or to the central nervous system.


NEUPOGEN   Dico Tools
See granulocyte colony-stimulating factor.


Neural   Dico Tools
Adjective, Greek neuron = nerve.


NEURALGIA   Dico Tools
Nerve pain.


Neuroglia   Dico Tools
Greek neuron = nerve, and gloia = glue; hence, the connective tissue of the central nervous system; adjective - neuroglial.


Neurohormones   Dico Tools
Biochemical substances made by tissue in the body's nervous system that can change the function or structure, or direct the activity of tissues or organs; e.g. neurotransmitters.


Neurohypophysis   Dico Tools
Or posterior lobe of hypophysis - Greek hypo = down, and physis = growth; hence, the posterior part of the hypophysis evaginated downwards from the diencephalon, and its stalk.


Neurolemma   Dico Tools
Greek neuron = nerve, and lemma = peel or rind; hence, the covering layer of a nerve.


Neurological   Dico Tools
Relating to the body's nervous system, which oversees and controls all body functions.


Neuron   Dico Tools
Greek = nerve; refers to the nerve cell body, with its axon and dendrites; adjective - neuronal.


NEUROPATHY (adjective NEUROPATHIC)   Dico Tools
Nerve damage or disease.


Neurotransmitters   Dico Tools
Biochemical substances that stimulate or inhibit nerve impulses in the brain that relay information about external stimuli and sensations, such as pain.


NEUTROPENIA   Dico Tools
An abnormally low number of neutrophils, resulting in increased susceptibility to infection.


NEUTROPHIL   Dico Tools
The most common type of immune system white blood cell. Neutrophils are phagocytes that engulf and destroy invading organisms such as bacteria and fungi.


NEW DRUG APPLICATION (NDA)   Dico Tools
An application made by a drug manufacturer to the FDA to request marketing approval for a new drug.


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NIACIN   Dico Tools
See vitamin B.


NIAID   Dico Tools
National Institute of Allergy and Infectious Diseases. See National Institutes of Health.


NIDDK   Dico Tools
National Institute of Diabetes and Digestive and Kidney Diseases. See National Institutes of Health.


Nigra   Dico Tools
Latin niger = black, dark.


NIH   Dico Tools
See National Institutes of Health.


NK (natural Killer) Cells   Dico Tools
Non-specific lymphocytes like killer T cells that attack and kill cancer and infected cells. They are natural killers because they do not need to recognize a specific antigen in order to attack and kill.


NK CELL   Dico Tools
See natural killer cell.


NNRTI   Dico Tools
See non-nucleoside reverse transcriptase inhibitor.


Nocturia   Dico Tools
Regularly needing to urinate more than twice during the night (see Urinary Incontinence).


Node   Dico Tools
Latin nodus = knot.


Nodule   Dico Tools
Diminutive of Latin nodus = knot, hence, a little knot.


NON-A/NON-B HEPATITIS   Dico Tools
See hepatitis C.


NON-HODGKIN’S LYMPHOMA (NHL)   Dico Tools
Cancer of lymphoid tissues.


NON-NUCLEOSIDE REVERSE TRANSCRIPTASEINHIBITOR (NNR   Dico Tools
An antiviral drug that suppresses viral replication by interfering with the action of the reverse transcriptase enzyme.


NON-NUCLEOSIDE REVERSE TRANSCRIPTASEINHIBITOR (NNR   Dico Tools
An antiviral drug that suppresses viral replication by interfering with the action of the reverse transcriptase enzyme.


NONINVASIVE   Dico Tools
A device or procedure that does not require puncturing the skin.


NONOXYNOL-9   Dico Tools
A chemical formerly used as a spermicide and microbicide. Recent studies have shown that nonoxynol-9 causes tissue damage and may increase the risk of STD transmission.


NONRESPONDER   Dico Tools
Person who does not show improvement while undergoing treatment. In HCV, a nonresponder does not achieve normal ALT levels or an undetectable viral load.


NONSTEROIDAL ANTI-INFLAMMATORY DRUG (NSAID)   Dico Tools
A drug (e.g., aspirin, acetaminophen, ibuprofen) that relieves pain and reduces inflammation by blocking the body's production of prostaglandins.


Norepinephrine   Dico Tools
A neurotransmitter that constricts blood vessels and plays a role in the regulation of anxiety, mood, and responses to stress. Sometimes called noradrenaline (see Anxiety, Depression, Hypertension).


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Norma   Dico Tools
Latin = pattern or rule, or aspect; adjective, normal - according to rule.


Notch   Dico Tools
An indentation in the margin of a structure. Etymology uncertain.


Notochord   Dico Tools
Greek notos = back, and chorde = cord; hence, the primitive axial skeleton around which the vertebrae develop, parts persisting in the nuclei pulposi.


NRTI   Dico Tools
See nucleoside reverse transcriptase inhibitor.


NSAID   Dico Tools
See nonsteroidal anti-inflammatory drug.


NSAID (nonsteroidal Anti-inflammatory Drug)   Dico Tools
Noncortisone, non-addictive (non-narcotic) drug that reduces pain and inflammation and is therefore used in the treatment of pain and arthritis.


NSAIDs   Dico Tools
Nonsteroidal anti-inflammatory drugs, used to treat inflammation, fever, and pain. NSAIDs do not treat the inflammation of asthmatic airways. People with aspirin-sensitive asthma suffer flare-ups of symptoms after taking most NSAIDs (see Asthma).


Nucha   Dico Tools
French nuque = nape or back of the neck; adjective - nuchal.


NUCLEOSIDE ANALOG   Dico Tools
See nucleoside reverse transcriptase inhibitor.


NUCLEOSIDE REVERSE TRANSCRIPTASE INHIBITOR (NRTI,   Dico Tools
A drug that mimics a nucleoside, one of the building blocks of genetic material (DNA or RNA). NRTIs suppress viral replication by interfering with the action of the reverse transcriptase enzyme, causing premature termination of new chains of genetic material.


NUCLEOSIDE REVERSE TRANSCRIPTASE INHIBITOR (NRTI,   Dico Tools
A drug that mimics a nucleoside, one of the building blocks of genetic material (DNA or RNA). NRTIs suppress viral replication by interfering with the action of the reverse transcriptase enzyme, causing premature termination of new chains of genetic material.


NUCLEOTIDE   Dico Tools
A genetic building block.


Nucleus   Dico Tools
The central controlling structure within a living cell that contains the genetic codes (in chromosomes) for maintaining life systems of the cell and for issuing commands for cell growth and reproduction.


NUTRIENT   Dico Tools
An agent that promotes proper growth and metabolism.


NUTRITION   Dico Tools
The process by which living organisms digest and metabolize food to use for maintenance and growth of tissues.


Nystagmus   Dico Tools
Greek = drowsiness, to nod, hence, involuntary, rapid, rhythmic eye movements.



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