| REST | Raynaud's phenomenon, esophageal motor dysfunction, sclerodactyly, and telangiectasia [syndrome]; re... |
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| RP | radial pulse; radiopharmaceutical; rapid processing [of film]; Raynaud phenomenon; reactive protein;... |
| SSP | Sanarelli-Shwartzman phenomenon; subacute sclerosing panencephalitis; slice sensitivity profile; sub... |
| TRAP | carpal tunnel syndrome, Raynaud phenomenon, aching muscles, proximal muscle weakness [rheumatic diso... |
| TLV | Threshold Limit Value |
| threshold percussion | Percussion effected by means of a glass rod as a plessimeter, the rod being inclined to the wall of the chest or abdomen and touching it only by one extremity. (05 Mar 2000) |
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| threshold shift | Measurement of the degree of hearing loss or impairment in terms of a decibel shift from an individual's previous audiogram. (05 Mar 2000) |
| threshold stimulus | A stimulus of threshold strength, i.e., one just strong enough to excite. See: adequate stimulus. Synonym: liminal stimulus. (05 Mar 2000) |
| threshold substance | Any material (e.g., glucose) that is excreted in the urine only when its plasma concentration exceeds a certain value, termed its threshold. Synonym: threshold body. (05 Mar 2000) |
| threshold trait | A trait that falls into natural groups that originate not in categorically distinct causes but in whether or not the outcome attains critical values; e.g., gallstones may result from a categorical cause or from unusual levels of causal factors that themselves show no evidence of grouping. Synonym: liminal trait. (05 Mar 2000) |
| transmission threshold | <epidemiology> Occurs for a parasite when the basic reproductive rate Ro is equal to 1. Below this threshold level the disease is unable to maintain itself within the host population. Typically, for directly transmitted parasites there is a transmission threshold for the host population size. (05 Dec 1998) |
| erythema threshold | The amount of radiation that causes redness of the skin. (09 Oct 1997) |
| fibrillation threshold | Least intensity of an electrical stimulus that will initiate fibrillation. (05 Mar 2000) |
| fusion-inferred threshold test | Employment of the phenomenon of cerebral fusion of binaural sounds to substitute for conventional masking in hearing testing. Synonym: FIT test. (05 Mar 2000) |
| light differential threshold | The smallest difference in light intensity that can be appreciated. (05 Mar 2000) |
| adhesion phenomenon | A phenomenon manifested by the adherence of antigen-antibody-complement complex to "indicator cells" (microorganisms, platelets, leukocytes, or erythrocytes), the reaction being sensitive and specific for the antigen and antibody in the complex. Synonym: erythrocyte adherence phenomenon, immune adherence phenomenon, red cell adherence phenomenon. (05 Mar 2000) |
| AFORMED phenomenon | As induced pulsus alternans progresses, a state in which alternating heart depolarisations fail to eject any blood, thus allowing longer diastolic filling; the subsequent beat is then able to produce a significant ejection; at high rates the cardiac minute volume and blood pressure may appear normal. Origin: Alternating, failure of response, mechanical, to electrical depolarisation (05 Mar 2000) |
| all-or-nothing phenomenon | <physiology> Refers to the phenomenon where the strength of a nerve impulse is not dependent on the strength of the stimulus. Instead, there is a threshold level of stimulus strength that must be reached before the nerve will fire an impulse (at full capacity). Below the threshold, the nerve will not fire at all. <cardiology> It also refers to the same phenomenon observed in the heart muscle, which will either contract fully or not at all. <psychology> In studies of behaviour, it refers to the same phenomenon where a behavioural stimulus will either produce a complete response or no response at all. Also called all-or-nothing principle, all-or-none law, all-or-none responsiveness, etc. (15 Nov 1997) |
| Anrep phenomenon | Homeometric autoregulation of the heart whereby cardiac performance improves as the afterload (aortic pressure) is increased. (05 Mar 2000) |
| aqueous influx phenomenon | The filling of the aqueous vein, which normally carries blood and aqueous, with aqueous, when the junction of the aqueous vein and the recipient vein is partially occluded. Synonym: Ascher's aqueous influx phenomenon. (05 Mar 2000) |