| transient hypogammaglobulinaemia of infancy | A type of primary immunodeficiency that occurs in infants of both sexes, usually before the sixth month of life, probably resulting from immaturity of lymphoid tissue. Synonym: transient agammaglobulinaemia. (05 Mar 2000) |
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| transient ischaemic attack | A transient ischaemic attack is a temporary paralysis, numbness, speech difficulty or other neurologic symptoms that start suddenly and recovers within 24 hours (typically resolve over several hours). See: neurologic symptoms, stroke. Acronym: TIA (26 Mar 1998) |
| transient ischemic attack | A sudden focal loss of neurological function with complete recovery usually within 24 hours; caused by a brief period of inadequate perfusion in a portion of the territory of the carotid or vertebral basilar arteries. (05 Mar 2000) |
| transient retinopathy | Transient traumatic retinal angiopathy due to a sudden rise in venous pressure, as in compression of the body from seat belt injury; ocular fundi show large white patches associated with the retinal veins about the disk or macula, haemorrhages, and retinal oedema; thought to be due to fat embolism from bone marrow. Synonym: Purtscher's disease, transient retinopathy, traumatic retinopathy. (05 Mar 2000) |
| epidemic transient diaphragmatic spasm | An acute infectious disease usually occurring in epidemic form, characterised by paroxysms of pain, usually in the chest, and associated with strains of Enterovirus coxsackievirus type B. Synonym: benign dry pleurisy, Bornholm disease, Daae's disease, devil's grip, diaphragmatic pleurisy, epidemic benign dry pleurisy, epidemic diaphragmatic pleurisy, epidemic myalgia, epidemic myositis, myositis epidemica acuta, epidemic transient diaphragmatic spasm, Sylvest's disease. (05 Mar 2000) |
| alternating light test | Test to detect a relative afferent defect in one eye by watching pupillary movements. With the patient fixing in the distance, the light is held on each eye for about a second, and quickly moved to the other eye. Assuming no defect of the innervation to the iris sphincter in one eye (which would produce an anisocoria in light), the eye with the weaker light response has a relative afferent pupillary defect. This asymmetry of pupillomotor input can be estimated by holding neutral density filters in front of the better eye until the pupillary responses of the two eyes are balanced. Synonym: swinging light test. (05 Mar 2000) |
| Begg light wire differential force technique | An orthodontic appliance utilizing small gauge labial wires with expansion and contraction loops formed into it and attached to bands fitted to individual teeth; sometimes called Begg light wire differential force technique. (05 Mar 2000) |
| gene rearrangement, b-lymphocyte, light chain | Ordered rearrangement of b-lymphocyte variable gene regions coding for the kappa or lambda light chains, thereby contributing to antibody diversity. It occurs during the second stage of differentiation of the immature b-lymphocyte. (12 Dec 1998) |
| ray, light | <microscopy> The term applied to the lines perpendicular to the wavefronts of waves of light to indicate their direction of travel in an isotropic medium. Note the wave normal and the ray do not coincide in isotropic media. (05 Aug 1998) |
| reflected light | Light directed backward from a mirror. (05 Mar 2000) |
| refracted light | Bent rays of light changed in passage from one transparent medium to another of unequal density. See: refraction. (05 Mar 2000) |
| visible light | <physics> Electromagnetic radiation with wavelengths between 400 nanometres and 750 nanometres. Electromagnetic radiation within this range can be detected by the human eye. Colours depend on the wavelength lengths, a short wavelength (the 400 nm side) looks blue and a long wavelength (the 750 nm side) looks red. (09 Oct 1997) |
| metals, light | Metals with low specific gravity, typically smaller than 5, characterised by a single valence (1, 2, or 3), a simple spectrum, strong electromotive force (positive), and colourless compounds. (12 Dec 1998) |
| minimum light | Threshold of visual sensation, the minimal light intensity evoking a visual sensation. Synonym: achromatic threshold, minimum light threshold. (05 Mar 2000) |
| minimum light threshold | Threshold of visual sensation, the minimal light intensity evoking a visual sensation. Synonym: achromatic threshold, minimum light threshold. (05 Mar 2000) |