| SMR | senior medical resident; sensorimotor rhythm; severe mental retardation; sexual maturity rating; ske... |
|---|---|
| SRR | standardized rate ratio; surgery recovery room |
| ACR | abnormally contracting region; absolute catabolic rate; acriflavine; adenomatosis of colon and rectu... |
| CR | calculation rate; calculus removed; calorie-restricted; cardiac rehabilitation; cardiac resuscitatio... |
| MR | Maddox rods; magnetic resistance; magnetic resonance; mandibular reflex; mannose-resistant; may repe... |
natural purification (자정 작용
| natural killer cell stimulating factor | <cytokine> A 75 kD heterodimeric cytokine composed of disulfide-bonded 40 kD and 35 kD subunits that was originally identified by its ability to induce cytotoxic effector cells in synergy with less than optimal concentrations of interleukin-2. It is released by macrophages in response to infection and promotes the activation of cell-mediated immunity. Specifically, IL-12 triggers the maturation of Thl CD4 cells, specific cytotoxic T-lymphocyte responses and an increase in the activity of NK cells and consequently, it is the initiator of cell-mediated immunity. It enhances the lytic activity of NK cells, induces interferon production, stimulates the proliferation of activated T-cells and NK cells. Is secreted by human B lymphoblastoid cells (NC 37). May play a role in controlling immunoglobulin isotype selection as it also inhibits IgE synthesis (even in the presence of anti-IFN monoclonal antibody) and as a growth factor for activated CD4+ and CD8+ T-cells independently of interleukin-2, and for CD56+ NK cells but not resting peripheral blood mononuclear cells or resting or activated tonsillar B-cells. It is likely that interleukin 12 has a major role in protective immunity against viruses and is under study as an immunotherapy in HIV infection. Formerly referred to as cytotoxic lymphocyte maturation factor. Acronym: IL-12 (12 Dec 1998) |
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| natural language processing | Computer processing of a language with rules that reflect and describe current usage rather than prescribed usage. (12 Dec 1998) |
| natural mutation | A mutation which occurs by itself without first being affected by a mutagen, for example during the process of DNA replication. Spontaneous mutations arise at a remarkably constant rate. The rate that spontaneous mutations arise has been used as an evolutionary clock to estimate how closely related two (or more) separate species are to each other. (09 Oct 1997) |
| natural passive immunity | Immunity conferred by the mother on the foetus or newborn. (14 Nov 1997) |
| natural pigment | A naturally occurring coloured compound; absorbs light in the visible range of the electromagnetic spectrum. Compare: structural colour. Synonym: biochrome. (05 Mar 2000) |
| natural products | Naturally occurring compounds that are end products of secondary metabolism; often, they are unique compounds for particular organisms or classes of organisms. (05 Mar 2000) |
| natural selection | The hypothesis that genotype environment interactions occurring at the phenotypic level lead to differential reproductive success of individuals and hence to modification of the gene pool of a population. (18 Nov 1997) |
| immunity, natural | The capacity of a normal organism to remain unaffected by microorganisms and their toxins. It results from non-specific mechanisms such as genetic endowment, naturally occurring antiviral and bactericidal substances, phagocytosis, and constitutional factors such as body temperature, oxygen tension, and age. (12 Dec 1998) |
| killer cells, natural | Cells responsible for spontaneous cytotoxicity of a variety of tumour cells without prior immunization. These natural killer cells are found in non-immune humans and experimental animals and are thought by some to be the same as killer cells (killing by antibody-dependent cell cytotoxicity), but they can also kill in the absence of antibody. (12 Dec 1998) |
| abortion rate | The number of abortions per 1000 terminated pregnancies during a given period of time. (05 Mar 2000) |
| age-specific rate | A rate for a specified age group, in which the numerator and denominator refer to the same age group. (05 Mar 2000) |
| attack rate | A cumulative incidence rate used for particular groups observed for limited periods under special circumstances, such as during an epidemic. (05 Mar 2000) |
| average flow rate | <physiology> The flow rate determined by dividing the total volume passed in a time period divided by the time period, usually quoted in mls per minute. (05 Mar 2000) |
| backup rate | A utility charge for providing occasional electricity service to replace on-site generation. (05 Dec 1998) |
| basal metabolic rate | <biochemistry, biology> The metabolic rate as measured under basal conditions: 12 hours after eating, after a restful sleep, no exercise or activity preceding test, elimination of emotional excitement and occurring in a comfortable temperature. Acronym: BMR (15 Nov 1997) |