Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «L»:
Leukocytes: Cells that help the body fight infections and other
diseases. Also called white blood cells (WBCs). ...
Leukocytosis: Increase in the number of white blood cells. ...
Leukodystrophy: A disorder of the white matter of the brain, the part of the brain that contains myelinated nerve fibers. The white matter is white because it is the color of myelin, the insulation covering the nerve fibers. (The white matter is as opposed to the gray matter, the cortex of the brain...
Leukoencephalopathy with vanishing white matter
Leukoencephalopathy with vanishing white matter: An inherited brain disease that occurs mainly in children. and follows a chronic progressive course with additional episodes of rapid deterioration following stress from febrile infection or minor head trauma.
Leukoencephalopathy with vanishing whit...
Leukomalacia, cystic periventricular
Leukomalacia, cystic periventricular: Softening of the white matter near the ventricles of the brain resulting in abnormal cysts.
Cystic periventricular leukomalacia is a major problem in very premature infants.
Treating the mother with a cortisone-like drug before the premature birth has been disco...
Leukopenia: Lower than the normal amount of white blood cells. ...
Leukoplakia: A white spot or patch on the mucous membranes in the mouth (for instance, inside the cheeks, on the gums or the tongue) that may become cancerous....
Leukoreduction: A process used to filter and remove white blood cells from whole blood before transfusion. The reason why white blood cells (leukocytes) are removed from blood is because they provide no benefit to the recipient but can carry bacteria and viruses to the recipient. Patients who receiv...
Leukotriene: One of a group of hormones that cause the symptoms of hay fever and asthma. Derived from arachidonic acid, the leukotrienes act by mediating immediate hypersensitivity. Leukotriene modifiers that prevent the production or action of leukotrienes are used to treat hay fever and asthma....
Level 1 biosafety
Level 1 biosafety: The lowest level of biosafety, a level that applies to agents that do not ordinarily cause human disease.
A biosafety level is a specific combination of work practices, safety equipment, and facilities which are designed to minimize the exposure of workers and the environment to ...
Level 2 biosafety
Level 2 biosafety: A level of biosafety considered appropriate for agents that can cause human disease, but whose potential for transmission is limited. A biosafety level is a specific combination of work practices, safety equipment, and facilities which are designed to minimize the exposure of work...
Level 3 biosafety
Level 3 biosafety: A level of biosafety considered appropriate for agents that may be transmitted by the respiratory route which can cause serious infection.
A biosafety level is a specific combination of work practices, safety equipment, and facilities which are designed to minimize the exposure o...
Level 4 biosafety
Level 4 biosafety: The highest level of biosafety. This level is used for the diagnosis of exotic agents such as the Ebola virus that pose a high risk of life-threatening disease, which may be transmitted by the aerosol route and for which there is no vaccine or therapy.
A biosafety level is a speci...
Levite: A member of an ancient caste of hereditary Jewish priests. Membership in the Levites is determined by paternal descent. The Levites have traditionally been considered the descendants of Levi, a son of Jacob. However, research has disclosed an unusual genetic signature called R1a1 on the Y ch...
Levo-: Prefix derived from the Latin "laevus"
meaning on the left side. A molecule that shows levorotation is turning or twisting to the left. The opposite of
levo- is dextro- which is derived from the Latin dexter meaning on the right side....