|Medical Dictionary - Dictionary of Medicine and Human Biology|
SYN: fructosan (1) .
An enzyme catalyzing transfer of the fructose moiety of sucrose to polyfructose (a levan), releasing d-glucose.
SYN: norepinephrine. l. bitartrate SYN: norepinephrine bitartrate.
levator (le-va′ter, tor) [TA]
1. A surgical instrument for prying up the depressed part in a fracture of the skull. 2. One of several muscles whose action is to raise the part to which it inserts. [L. a lifter, fr. levo, pp. -atus, to lift, fr. levis, light]
Harry H., U.S. surgeon, *1914. See L. shunt.
1. Any rank, position, or status in a graded scale of values. 2. A test for determining such rank or position. acoustic reference l. the biological reference l. for sound measurements. When the term decibel is used to indicate the noise l., a reference quantity is implied; this reference value is usually expressed as a sound pressure of 20 micronewtons per square meter. The reference l. is referred to as 0 decibels, the baseline of the scale of noise levels; this baseline is considered the weakest sound that can be heard by a person with very good hearing in an extremely quiet location. Other equivalent reference levels still being used include 0.0002 microbar and 0.0002 dyne per square centimeter. SEE ALSO: sound pressure l.. l. of aspiration in clinical psychology, the degree or quality of performance (exhibited in a testing situation) which a person desires to attain or feels he or she can achieve. background l. the concentration (usually low) at which a substance or agent is present or occurs at a particular time and place in the absence of a specific hazard under investigation; an example is the background l. of ionizing radiation. Clark l. the l. of invasion of primary malignant melanoma of the skin; limited to the epidermis, I; into the underlying papillary dermis, II; to the junction of the papillary and reticular dermis, III; into the reticular dermis, IV; into the subcutaneous fat, V. The prognosis is worse with each successive deeper l. of invasion. hearing l. the measure of the status of hearing as read directly on the hearing loss scale of an audiometer; described in decibels as a deviation from a standard value for zero on the audiometer. loudness discomfort l. the intensity at which sound, particularly speech, causes discomfort. most comfortable l. the greatest sound intensity that is comfortable. saturation sound pressure l. (SSPL) a measure of the maximum output of a hearing aid. sensation l. the amount in decibels that a stimulus is above the hearing threshold. sensory acuity l. a technique for determining air conduction thresholds without masking and with masking presented by bone conduction to the forehead; the change in thresholds indicates the conductive hearing loss. sound pressure l. (SPL) a measure of sound energy relative to 0.0002 dynes/cm2, expressed in decibels. uncomfortable l. the intensity of sound that causes discomfort. window l. the CT number setting in Hounsfield units of the midpoint of the window width, which is the gray scale of the image; a typical window l. for imaging the lungs is −500; for the abdomen, 0.
Michael L., U.S. obstetrician-gynecologist, 1901–1971. See Stein-L. syndrome.
lever (lev′er, le′ver)
An instrument used to lift or pry. [Fr. l., to lift] dental l. SYN: elevator (2) .
1. The actual lift or elevating direction of a lever or elevator. 2. The mechanical advantage gained thereby.
S., 20th century U.S. statistician. See L.-Jennings chart.
E. Leopold, French endocrinologist, 1868–1933. See dominantly inherited L. disease, Lorain-L. dwarfism, Lorain-L. infantilism, Lorain-L. syndrome.
Abraham, U.S. physician, 1880–1940. See L. tube.
Max, U.S. neurologist, *1901. See Kleine-L. syndrome.
Samuel A., U.S. cardiologist, 1891–1966. See Lown-Ganong-L. syndrome.
A former genus of bacteria (of the family Enterobacteriaceae) whose species are now assigned to the genus Citrobacter. [Max Levine, U.S. bacteriologist, *1889] L. amalonatica SYN: Citrobacter amalonatica. L. diversus SYN: Citrobacter diversus. L. malonatica SYN: Citrobacter diversus.
Support of the patient on a cushion of air. [L. levitas, lightness]
Provisional name for a family of small, nonenveloped, isometric bacterial viruses with genomes of single-stranded positive sense RNA (MW 1 × 106). Virions adsorb to the sides of bacterial pili, and crystalline arrays are formed in infected bacteria. The type species is enterobacteria phage M52. [L. levis, light (not heavy)]
Left, toward or on the left side. [L. laevus]
levobunolol hydrochloride (le-vo-bu′no-lol)
A β-adrenergic blocking agent used primarily as an eye drop in the treatment of chronic open-angle glaucoma and ocular hypertension.
Situs inversus of the other viscera but with the heart normally situated on the left; congenital cardiac lesions are commonly associated. [levo- + G. kardia, heart]
That part of the electrocardiogram that is the effect of the left ventricle.
Used as a supplement for carnitine deficiency.
SYN: levotorsion (2) . [levo- + L. clino, pp. -atus, to bend]
levotorsion of one eye. [levo- + cyclo- + L. duco, pp. ductus, to lead]
The biologically active form of dopa; an antiparkinsonian agent that is converted to dopamine. SYN: l-dopa.
Turning of one eye to the left; abduction of left eye or adduction of right eye. [levo- + L. duco, pp. ductus, to lead]
Denoting the structure of a substance that rotates the plane of polarized light counterclockwise (left); that is, as viewed by the observer looking toward the light source.
d-Fructose. See fructose.
Electrocardiographic record in an experimental animal representing spread of impulse through the left ventricle alone.
levogyrate, levogyrous (le-vo-ji′rat, -ji′rus)
SYN: levorotatory. [levo- + L. gyro, to turn in a circle]
Used as a nasal decongestant and as a vasoconstrictor given with infiltration anesthetics.
An antidepressant with anorexigenic properties.
Fear of objects to the left.
levopropoxyphene napsylate (le′vo-pro-pok′si-fen)
1. A turning or twisting to the left; in particular, the counterclockwise twist given the plane of plane-polarized light by solutions of certain optically active substances. Cf.:dextrorotation. 2. SYN: sinistrotorsion. [levo- + L. roto, to turn]
1. Denoting levorotation, or certain crystals or solutions capable of causing it; as a chemical prefix, usually abbreviated l- or (−). Cf.:dextrorotatory. 2. Describing any leftward or anticlockwise rotation. SYN: levogyrate, levogyrous.
levorphanol tartrate (lev-orf′a-nol)
An analgesic similar in action to morphine.
1. SYN: sinistrotorsion. 2. Rotation of the upper pole of the cornea of one or both eyes to the left. SYN: levoclination. [levo- + L. torsio, a twisting]
1. Version toward the left. 2. Conjugate turning of both eyes to the left. [levo- + L. verto, pp. versus, to turn]
André, French obstetrician, 1703–1780. See L. forceps, Mauriceau-L. maneuver.
SYN: fructosan (1) .
levulic acid (lev′u-lik)
SYN: levulinic acid.
SYN: fructosan (1) .
A salt or ester of levulinic acid.
levulinic acid (lev-u-lin′ik)
4-Oxopentanoic acid;formed by the action of hot, strong acids on hexoses. SEE ALSO: δ-aminolevulinic acid. SYN: levulic acid.
SYN: fructosan (1) .
d-Fructose. See fructose.
Gabrielle, French neurologist, 1886–1935. See Roussy-L. disease, Roussy-L. syndrome.
Felix, German dermatologist, 1879–1921. See Jadassohn-L. syndrome.
Gilbert N., U.S. chemist, 1875–1946. SEE ALSO: L. acid, L. base, second law of thermodynamics.
Ivor, Welsh surgeon who in 1946 reported to the Royal College of Surgeons a two-stage esophagectomy by laparotomy and right thoracotomy, performed today as one procedure. See Ivor L. esophagectomy.
Lewis Blood Group, Le Blood Group
See Blood Groups Appendix.
A war gas. It is a vesicant, a lung irritant like mustard gas, a systemic poison entering the circulation through the lungs or skin, and a mitotic poison arresting mitosis in the metaphase; dimercaprol is the antidote. SYN: β-chlorovinyldichloroarsine. [W. Lee Lewis, U.S. chemist, 1898–1943]
Frederic H., German neurologist in the U.S., 1885–1950. See L. bodies, under body, L. body dementia, diffuse L. body disease.
Denoting the vocabulary of speech or language.
Suffixes that properly relate to speech, although often confused with -legia (L. lego, to read) and thus erroneously employed to relate to reading. [G. lexis, word, speech, from lego, to say]
Ernst V. von, German physician, 1832–1910. See L. ataxia, L. crystals, under crystal, L. neuritis, L.-Möbius muscular dystrophy.
Franz von, German anatomist, 1821–1908. See L. cells, under cell, L. cell tumor, Sertoli-L. cell tumor.
Obsolete term for the beginning of gonadal function in the male, e.g., male puberty. [Leydig (see Leydig cells), + G. arche, beginning]
Abbreviation for left frontoanterior position; lymphocyte function associated antigen.
Abbreviation for left frontoposterior position.
Abbreviation for left frontotransverse position.
Abbreviation for low-grade squamous intraepithelial lesion.
Abbreviation for luteinizing hormone.
Jean, French neurologist, 1877–1959. See L. sign.
Abbreviation for luteinizing hormone/follicle-stimulating hormone-releasing factor.
Abbreviation for luteinizing hormone-releasing factor.
Abbreviation for luteinizing hormone-releasing hormone.
Frederick P., 20th century epidemiologist. See L.-Fraumeni cancer syndrome.
Symbol for lithium.
liberator (lib′er-a-ter, -tor)
An agent that stimulates or activates a physiological chemical or an enzymatic action. histamine liberators substances that cause the release of histamine from mast cells or basophils.
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