Glossary of HIV/AIDS Terms
This glossary contains 1,600 terms and is maintained by the editors of the San Francisco AIDS Foundation's Bulletin of Experimental Treatments for AIDS.
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nadir: the lowest point; the term is used to refer to the lowest CD4 cell count an individual ever reached.
naive: inexperienced; the term is used to refer to an individual who has never taken a certain drug or class of drugs (e.g., AZT-naive, antiretroviral-naive). See also naive T cell.
naive T cell: an undifferentiated CD4 or CD8 cell that proliferates rapidly when exposed to new antigens; naive cells have not yet specialized to respond to a specific pathogen. Compare with memory cell.
narcotic: a drug that dulls the senses and induces sleep; usually refers to opiates.
natal: refers to birth.
National Cancer Institute (acronym NCI): a U.S. government research agency, part of the National Institutes of Health, that focuses on malignant diseases.
National Institute of Allergy and Infectious Disea (acronym NIAID): a U.S. government research agency, part of the National Institutes of Health, that conducts federally-funded research aimed at preventing, diagnosing, and treating infectious diseases such as HIV/AIDS and tuberculosis.
National Institutes of Health (acronym NIH): a large biomedical research organization that is part of the U.S. Public Health Service, under the Department of Health and Human Services. The NIH includes more than 25 institutes and centers, including NIAID, which conducts most HIV/AIDS research.
natural history study: a study of the development of a disease over time.
natural killer cell (aka NK cell): a type of white blood cell that attacks and kills tumor cells and cells infected with microorganisms; unlike cytotoxic T lymphocytes, NK cells are nonspecific and attack infected cells without regard to specific antigens or MHC receptor configuration.
naturopathy: a system of natural healing that relies on healthy foods, exercise, and the avoidance of medications, believing that the body can cure itself.
nausea: stomach distress characterized by an aversion to food and an urge to vomit.
NDA: See new drug application.
nebulizer: a device used to convert liquid medication to a fine mist that can be inhaled.
necrolysis: peeling away or sloughing of tissue following tissue death.
necrosis: tissue death.
nef: an HIV gene that influences viral replication and may help the virus evade host defenses; also refers to the protein (Nef) produced by this gene.
nelfinavir (brand name Viracept): a protease inhibitor drug approved for use as part of combination antiretroviral therapy to treat HIV disease.
neonate (adjective neonatal): a newborn, especially within the first weeks after birth.
neoplasia: abnormal cell growth that may progress to cancer.
neoplasm: a tumor or growth; tissue that develops abnormally or grows more rapidly than normal. Benign neoplasms (e.g., warts) do not spread to other tissues, while malignant (cancerous) neoplasms have the potential to spread (metastasize) to other sites.
nephrolithiasis: See kidney stone.
nephrotoxic (noun nephrotoxicity): poisonous or harmful to the kidneys.
nerve: a structure composed of fibers that conduct impulses between the central nervous system (the brain and spinal cord) and other part of the body. See also neuron.
neural: refers to neurons.
neuralgia: pain along a nerve pathway.
neuritis: nerve inflammation.
neurological: refers to the central or peripheral nervous system.
neurology: the medical specialty concerned with the nervous system and its disorders.
neuron (aka nerve cell): a cell that conducts electric neural impulses. Neurons consist of dendrites (branch-like fibers that receive impulses) and axons (fibers that transmit impulses); they communicate with other neurons and organs at junctures called synapses.
neuropathy (adjective neuropathic): damage to the nerves; an inflammatory or degenerative condition of the nervous system. See also peripheral neuropathy.
neurotoxic (noun neurotoxicity): poisonous or harmful to the nervous system.
neurotoxic neuropathy: a form of nerve damage caused by drugs.
neurotransmitter: a chemical messenger (e.g., acetylcholine, dopamine, serotonin) that mediates communication among neurons and between neurons and other types of cells.
neutralizing antibody: an antibody that neutralizes (renders harmless) an infectious microorganism.
neutropenia: an abnormally low number of neutrophils (a type of white blood cell) in the circulating blood, resulting in increased susceptibility to infection.
neutrophil: a type of white blood cell that engulfs and destroys bacteria and fungi; neutrophils are the most numerous white blood cells.
nevirapine (brand name Viramune): a non-nucleoside reverse transcriptase inhibitor drug approved for use as part of combination antiretroviral therapy to treat HIV disease.
new drug application (acronym NDA): an application made by a drug manufacturer to the FDA requesting marketing approval of a new drug; a supplemental NDA is a subsequent application requesting approval for a new indication.
New-Fill: See polylactic acid.
NHL: See non-Hodgkin's lymphoma.
niacin (aka nicotinic acid, aka vitamin B3): Niacin is used as cholesterol-lowering drug. See vitamin B.
NIAID: See National Institute of Allergy and Infectious Disea.
NIDDM: See diabetes.
NIH: See National Institutes of Health.
nitrite inhalant (aka poppers): a volatile chemical preparation that expands blood vessels. Some forms (e.g., amyl nitrite, butyl nitrite) are used recreationally; some studies have linked inhalant use to immunosuppression.
NK cell: See natural killer cell.
NNRTI: See non-nucleoside reverse transcriptase inhibitor.
nodule: a hard knot, lump, or swelling.
non-Hodgkin's lymphoma (acronym NHL): a type of cancer of the lymphatic system characterized by abnormal growth of lymphocytes, usually B cells; NHL is the most common type of lymphoma in people with HIV/AIDS.
non-nucleoside reverse transcriptase inhibitor (acronym NNRTI): a drug (e.g., nevirapine, delavirdine, efavirenz) that binds to the reverse transcriptase enzyme of a retrovirus and prevents it from converting viral RNA to DNA, thus blocking viral replication.
nonoxynol-9 (acronym N-9): a surfactant chemical used as a spermicide and microbicide; N-9 can cause vaginal and rectal tissue damage and is not recommended for preventing HIV transmission.
nonresponder: an individual who does not show improvement (e.g., decreased viral load) while undergoing treatment.
nonspecific immunity (aka innate immunity): the immune system?s immediate first line of defense; in nonspecific immunity, various defenses, including the complement system and phagocytic cells (e.g., macrophages, dendritic cells, neutrophils) destroy, neutralize, or ingest invaders without regard for their specific antigenic identity. Compare with specific immunity.
nonsteroidal anti-inflammatory drug (acronym NSAID): a class of drugs (e.g., aspirin, acetaminophen, ibuprofen) that relieve pain and reduce inflammation and fever.
non-syncytium-inducing (NSI) strain: an HIV strain that preferentially infects macrophages rather than T-cells (therefore called "macrophage-tropic" or "M-tropic"); when sexually transmitted, HIV generally establishes itself in the body as an NSI strain. Contrast with syncytium-inducing (SI) strain.
Norvir: brand name of ritonavir.
nosocomial: refers to the acquisition of a new disease or condition within a medical setting, for example a hospital-acquired infection.
NRTI: See nucleoside reverse transcriptase inhibitor.
NSAID: See nonsteroidal anti-inflammatory drug.
NSI: See non-syncytium-inducing (NSI) strain.
NtRTI:
nucleic acid: See deoxyribonucleic acid. See ribonucleic acid.
nucleic acid sequence-based amplification (acronym NASBA): a type of viral load assay.
nucleoside: a precursor compound that is a converted to a nucleotide by the addition of a phosphate group.
nucleoside analog: See nucleoside reverse transcriptase inhibitor.
nucleoside reverse transcriptase inhibitor (acronym NRTI, aka nucleoside analog): an agent (e.g., AZT, 3TC, abacavir) that mimics one of the building blocks of genetic material; these compounds suppress retrovirus replication by interfering with the reverse transcriptase enzyme, causing premature termination of DNA copying.
nucleotide: one of the building blocks that make up genetic material (DNA and RNA); nucleotides consist of a base (adenine, cytosine, guanine, thymine, or uracil), a sugar, and a phosphate group.
nucleotide analog: See nucleotide reverse transcriptase inhibitor.
nucleotide reverse transcriptase inhibitor (acronym NtRTI, aka nucleotide analog): an agent (e.g., tenofovir) that is similar to a nucleoside reverse transcriptase inhibitor but already contains a phosphate group and is ready to be added to a new DNA chain; these compounds suppress retrovirus replication by interfering with the reverse transcriptase enzyme, causing premature termination of DNA copying.
nucleus: the central part of a cell that contains its genetic material.
nutrient: a substance taken in by an organism and metabolized to provide energy and promote growth; essential nutrients include carbohydrates, proteins, fats, vitamins, and minerals.
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