| MLF | medial longitudinal fasciculus; morphine-like factor |
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| MLS | mean lifespan; median life span; median longitudinal section; microphthalmia-linear skin defects [sy... |
| Mz | longitudinal magnetization |
| OALL | ossification of anterior longitudinal ligament |
| OPLL | ossification of posterior longitudinal ligament |
| oxidation-reduction indicator | A substance that undergoes a definite colour change at a specific oxidation potential. Synonym: redox indicator. (05 Mar 2000) |
|---|---|
| oxidation-reduction potential | <chemistry, physics> The potential in volts of an inert metallic electrode measured in a system of an arbitrarily chosen ratio of [oxidant] to [reductant] and referred to the normal hydrogen electrode at absolute temperature. It is calculated from the following equation: where R is the gas constant expressed in electrical units, T the absolute temperature (Kelvin), n the number of electrons transferred, F the faraday and E0 the normal symbol for the potential of the system at pH 0; for biological systems E0' is often used (in which pH = 7). Compare: Nernst's equation. Synonym: redox potential. (05 Mar 2000) |
| oxidation-reduction reaction | <chemistry> Any reaction in which electrons are removed from one molecule or atom and given to another molecule or atom. (09 Oct 1997) |
| oxidation-reduction system | <enzyme> An enzyme system in the tissues by which oxidation and reduction proceed simultaneously through the transference of hydrogen or of one or more electrons from one metabolite to another. See: oxidation-reduction. Synonym: redox system. (05 Mar 2000) |
| tuberosity reduction | The surgical excision of excessive fibrous or bony tissue in the area of the maxillary tuberosity prior to the construction of prosthetic appliances. (05 Mar 2000) |
| acquired platelet function defect | <haematology> Platelet function can be affected by a number of different disease processes including polycythaemia vera, leukaemia, myelofibrosis, renal failure, multiple myeloma and some medications (for example penicillins, salicylates, phenothiazines). Disturbed blood clotting can be manifested by: easy bruising, bleeding gums, nosebleeds, abnormal vaginal bleeding, rectal bleeding, skin rash, vomiting blood, coughing up blood or blood in the urine. A measure of bleeding time and coagulation profile will be part of the evaluation. (29 Dec 1997) |
| aortic septal defect | A small congenital opening between the aorta and pulmonary artery about 1 cm above the semilunar valves, e.g., aorticopulmonary window. Synonym: aorticopulmonary window. (05 Mar 2000) |
| aortopulmonary septal defect | A congenital anomaly in which there is abnormal communication between the ascending aorta and pulmonary artery just above the semilunar valves. (12 Dec 1998) |
| atrial septal defect | <cardiology> An inherited condition where there is nonclosure of the foramen ovale at birth, resulting in congenital heart disease. Usually asymptomatic until the third or fourth decades of life. Symptoms include exertional shortness of breath, fatigue and palpitations. Acronym: ASD (12 Jan 1998) |
| atrial ventricular canal defect | A defect caused by deficient or absent septal tissue immediately above and below the normal level of the atrioventricular valves, including the region normally occupied by the A-V septum in hearts with two ventricles. The A-V valves are abnormal to a varying degree. (05 Mar 2000) |
| birth defect | Defect present at birth; sometimes referred to as congenital defect. (05 Mar 2000) |
| ventricular septal defect | <cardiology, embryology> A congenital heart defect where an abnormal opening exists in the ventricular septum. Blood flows from the higher pressure left ventricle (through the defect) into the right ventricle. (12 Jan 1998) |
| Gerbode defect | <cardiology, embryology> A defect in the interventricular portion of the membranous septum, associated with a communication between the right ventricle and the right atrium through an abnormality in the tricuspid valve. (05 Mar 2000) |
| mass defect | <chemistry, radiobiology> Of a nucleus, the difference between the sum of the masses of the constituent nucleons and the mass of the nucleus. (16 Dec 1997) |
| partial endocardial cushion defect | <radiology> Incomplete endocardial cushion defect components: ostium primum atrial septal defect, cleft in anterior mitral valve findings: right AV valve is usually normal, with or without mitral insufficiency, communication between LA_RA or LV-RA, occasionally LV-RV Cf: complete endocardial cushion defect (12 Dec 1998) |