Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «L»:
LDL (low-density lipoprotein)
LDL (low-density lipoprotein): A molecule that is a
combination of lipid (fat) and protein. Lipoproteins are the form in which lipids are transported in the blood.
Low-density lipoprotein (LDL) transports cholesterol from the liver to the tissues of the body. LDL cholesterol is therefore considere...
LDL cholesterol: Lipoproteins which are
combinations of lipids (fats) and proteins are the form in which
lipids are transported in the blood. The low-density lipoproteins
cholesterol from the liver to the tissues of the body. LDL
cholesterol is therefore
considered the "bad" cholester...
Lead poisoning: An environmental hazard capable of causing brain
damage. In the US lead poisoning is formally defined as having at least 10
micrograms of lead per deciliter of blood. (The average level of lead, for
people ages 1 to 70, is 2.3 micrograms.)
The lead may come, for example, from lead-co...
Lead-based paint: Paint or other surface coatings that, by definition, contain lead in excess of 1.0 milligrams per square centimeter (mg/cm2) 0.5 percent by weight....
Leaded: 1. Framed, covered, or weighted with lead. As a leaded window. 2. Added in the form of tetraethyl lead as an anti-knock agent to gasoline (petrol).
See: Lead poisoning....
Leaded gasoline: See: Tetraethyl lead....
Leaded petrol: See: Tetraethyl lead....
Lean body mass
Lean body mass: The mass of the body minus the fat (storage lipid). There are a number of methods for determining the lean body mass. Some of these methods require specialized equipment such as underwater weighing (hydrostatic weighing), BOD POD (a computerized chamber), and DEXA (dual-energy X-ray...
Learning disability: A
childhood disorder characterized by difficulty with certain skills such as
reading or writing in individuals with normal intelligence. Learning disorders
affect the ability to interpret what one sees and hears or the ability to link information from different parts of the b...
Learning problem: See: Learning disability....
Lecithinase: See: Phospholipase....
Lectin: A complex molecule that contains both protein and sugar. Lectins are made by both animals and plants and are able to bind to the outside of a cell and cause biochemical changes in it....
Lederberg: See: Lederberg, Joshua...
Lederberg, Joshua: (1925- ) American geneticist and microbiologist who received the Nobel prize in 1958 for his work in bacterial genetics. He shared the prize with George W. Beadle and Edward L. Tatum, who won "for their discovery that
genes act by regulating definite chemical events."
Leech: 1. An aquatic parasite that sucks blood from animals. Leeches play a role in medicine today. See: Leech therapy.
2. (Archaic) A physician or surgeon (because they did so much leeching). 3. A person who behaves as a parasite....