| low density lipoprotein | <biochemistry> A lipoprotein substances (combination of a fat and a protein) which acts as a carrier for cholesterol and fats in the bloodstream. High levels of low density lipoprotein are considered a positive risk factor for the development of coronary artery disease. Less than 130 mg/dl is desirable, 130 to 159 mg/dl is borderline high, over 160 is considered high. Acronym: LDL (10 Jan 1998) |
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| low density lipoprotein receptor | <biochemistry> A cell surface protein that mediates the endocytosis of low density lipoprotein by cells. Genetic defects in low density lipoprotein receptors lead to abnormal serum levels of low density lipoprotein and hypercholesterolaemia. (16 Mar 1998) |
| low-density lipoprotein receptors | Receptors on the surface of cells, especially liver cells, which bind to low density lipoprotein and promote clearance of LDL from the plasma. (05 Mar 2000) |
| low-egg-passage vaccine | See: rabies vaccine, Flury strain egg-passage. (05 Mar 2000) |
| low-fat diet | A diet containing minimal amounts of fat.Diets containing low amounts of fat and cholesterol are designed to reduce the risk of heart disease and, in some cases, cancer. Dozens of such diets have been promulgated, both by medical and lay advisors. Their popularity can be attributed in part to clinical studies that have, since the 1980s, revealed, on the one hand, the hazards of eating high-fat, high-cholesterol foods and, on the other, the benefits of ingesting less saturated fat and LDL (low density lipoprotein) cholesterol. Although coronary deaths have been reduced by roughly 30% since 1970, the aim of health officials is to further reduce heart attack rates. The average cholesterol level among adult Americans has fallen from 213 to 205 mg/dl since 1978. However, the National Cholesterol Education Program recommends that individuals maintain a total cholesterol level of no more than 200 mg/dl, with LDL at less than 130 mg/dl and HDL (high density lipoprotein) around 60 mg/dl. About one-half of American adults exceed those recommendations. Low-fat, low-cholesterol diets are rich in whole grains, fresh fruits and vegetables, and legumes, and limit or exclude consumption of processed oils, dairy products, nuts and seeds, and meats. See atherosclerosis, free radicals. (05 Mar 2000) |
| low flow principle | A principle based on the observation that animals can survive prolonged vena caval occlusion without sequelae: if blood from the azygos vein alone is permitted to enter the heart, patients are perfused during cardiac and pulmonary bypass at flows much less than the normal resting cardiac output. Synonym: low flow principle. (05 Mar 2000) |
| low forceps delivery | Delivery by forceps applied to the foetal head after it is clearly visible, the skull has reached the perineal floor, and plus 2 (+2) station. This classification of forceps delivery may be with or without rotation of the foetal head. (05 Mar 2000) |
| low frequency transduction | Specialised transduction in which only a small portion of the prophage particles, because of their defectiveness, are able to develop sufficiently to serve as effective transducing agents. (05 Mar 2000) |
| Low, George | <person> English physician, 1872-1952. See: Castellani-Low sign. (05 Mar 2000) |
| low grade astrocytoma | <tumour> Astrocytoma characterised by an increased cellularity of uneven distribution and mild nuclear pleomorphism. (05 Mar 2000) |
| low lip line | The lowest position of the lower lip during the act of smiling or voluntary retraction, the lowest position of the upper lip at rest. (05 Mar 2000) |
| low malignant potential tumour | A neoplasm of the ovary, usually arising in young women, composed of complex epithelial hyperplasia without stromas invasion; may recur if incompletely removed surgically, but is clinically less aggressive than carcinoma. Synonym: low malignant potential tumour. (05 Mar 2000) |
| low-necked | Cut low in the neck; decollete; said of a woman's dress. Source: Websters Dictionary (01 Mar 1998) |
| low output failure | Heart failure in which the cardiac output is subnormal, as is usually seen in failure due to coronary, hypertensive, or valvular heart disease. (05 Mar 2000) |
| low-pass filter | A device or material with the opposite effect from a high-pass filter; most tissues act as low-pass filters of ultrasound signals. (05 Mar 2000) |