L

L L left; leucine; liter; lung; lumbar vertebrae (L1-L5).

L– chemical prefix specifiying the relative configuration of an enantiomer, indicating a carbohydrate with the same configuration around a specific carbon atom as l-glyceraldehyde or an amino acid having the same configuration as l-serine. Opposed to d-.

l L former symbol for liter.

l. L. [L.] ligamentum (ligament).

l L length.

l – L – levo- (left, counterclockwise, levorotatory). Opposed to d-.

λ λ (lambda, the eleventh letter of the Greek alphabet) wavelength; one of the two types of immunoglobulin light chains.

La La lanthanum.

label 1. étiquette a mark, tag, or other characteristic that identifies something. 2. marquer to provide something with such a characteristic. radioactive l. traceur radioactif a radioisotope that is incorporated into a compound to mark it.

labetalol labétalol a beta-adrenergic blocking agent with some alpha-adrenergic blocking activity; used in the form of the hydrochloride salt as an antihypertensive.

labia labia plural of labium.

labial labial 1. pertaining to a lip or labium. 2. in dental anatomy, pertaining to the tooth surface that faces the lip.

labially labialement toward the lips.

labile labile 1. gliding; moving from point to point over the surface; unstable; fluctuating. 2. chemically unstable.

lability labilité 1. the quality of being labile. 2. in psychiatry, emotional instability.

labio- labio- word element [L.], lip.

labioalveolar labio-alvéolaire 1. pertaining to the lip and dental alveoli. 2. pertaining to the labial side of a dental alveolus.

labiochorea chorée labiale a choreic affection of the lips in speech, with stammering.

labioclination inclinaison labiale deviation of an anterior tooth from the vertical, in the direction of the lips.

labiograph labiographe an instrument for recording lip motions in speaking.

labiomental labiomentonnier pertaining to the lip and chin.

labioplacement labioversion displacement of a tooth toward the lip.

labioversion proalvéolie labial displacement of a tooth from the line of occlusion.

labium pl. labia [L.] labium 1. lip. 2. a fleshy border or edge; a liplike structure. 3. in the plural, often used to denote the labia majora and minora pudendi. Adj.: labial. labia majora pudendi l. majora pudendi, grandes lèvres elongated folds running downward and backward from the mons pubis in the female, one on either side of the rima pudendi. labia minora pudendi l. minora pudendi, petites lèvres small skin folds, one on each side, running backward from the clitoris between the labia majora and the vaginal opening. labia oris l. oris the lips of the mouth.

labor travail [L.] the function of the female by which the infant is expelled through the vagina to the outside world: the first stage begins with onset of regular uterine contractions and ends when the os is completely dilated and flush with the vagina; the second extends from the end of the first stage until the expulsion of the infant is completed; the third extends from expulsion of the infant until the placenta and membranes are expelled; the fourth denotes the hour or two after delivery, when uterine tone is established. artificial l. accouchement artificiel induced l. dry l. accouchement à sec that in which the amniotic fluid escapes before the onset of uterine contractions. false l. faux t. see under pain. induced l. t. provoqué that brought on by mechanical or other extraneous means, usually by the intravenous infusion of oxytocin. missed l. rétention fœtale that in which contractions begin and then cease, the fetus being retained for weeks or months. postmature l., postponed l. accouchement post-mature that occurring two weeks or more after the expected date of confinement. precipitate l. t. précipité that occurring with undue rapidity. premature l., preterm l. t. prématuré labor before the normal end of gestation; usually meaning between the twentieth and thirty-seventh weeks.

laboratory laboratoire a place equipped for making tests or doing experimental work. clinical l. l. clinique one for examination of materials derived from the human body for the purpose of providing information on diagnosis, prognosis, prevention, or treatment of disease.

labrum bourrelet, marginal pl. labra [L.] an edge, rim, or lip.

labyrinth labyrinthe 1. a system of interconnecting channels. 2. inner ear. Adj.: labyrinthine. bony l. l. osseux the bony part of the inner ear. cochlear l. l. cochléaire the part of the membranous labyrinth that includes the perilymphatic space and the cochlear duct. endolymphatic l. l. endolymphatique membranous l. ethmoidal l. l. ethmoïdal either of the paired lateral masses of the ethmoid bone, which contain many thin-walled cellular cavities. membranous l. l. membraneux a system of communicating epithelial sacs and ducts within the bony labyrinth, containing the endolymph. osseous l. l. osseux bony l. perilymphatic l. l. périlymphatique perilymphatic space. vestibular l. l. vestibulaire the part of the membranous labyrinth that includes the utricle, saccule, and semicircular ducts.

labyrinthitis labyrinthite otitis interna; inflammation of the inner ear. acute serous l. l. séreuse aiguë a type caused by chemical or toxic irritants that invade the labyrinth, usually from the middle ear. acute suppurative l. l. purulente aiguë a type in which pus enters the labyrinth, usually either through a fistula after infection of the middle ear or through temporal bone erosion from meningitis. circumscribed l. l. circonscrite perilabyrinthitis; acute serous labyrinthitis in a discrete area, due to erosion of the bony wall of a semicircular canal with exposure of the membranous labyrinth.

labyrinthus pl. labyrinthi [L.] labyrinthus labyrinth.

lac [L.] 1. lac milk. 2. lac, lait any milklike medicinal preparation.

lacerated lacéré torn; mangled; wounded by a jagged instrument.

laceration lacération 1. the act of tearing. 2. a torn, ragged, mangled wound.

lacertus lacertiens [L.] a name given certain fibrous attachments of muscles.

lacrimal lacrymal pertaining to the tears.

lacrimation larmoiement secretion and discharge of tears.

lacrimator lacrymogène an agent, as a gas, that induces the flow of tears.

lacrimotomy lacrymotomie incision of the lacrimal gland, duct, or sac.

lactacidemia lactacidémie excess of lactic acid in the blood.

lactagogue lactogogue galactagogue.

lactam lactame a cyclic amide formed from aminocarboxylic acids by elimination of water; lactams are isomeric with lactims, which are enol forms of lactams. β-l. β-l. see under antibiotic.

β-lactamase β-lactamase any of a group of enzymes, produced by almost all gram-negative bacteria, that hydrolyze the β-lactam ring of penicillins and cephalosporins, destroying their antibiotic activity. Individual enzymes may be called penicillinases or cephalosporinases based on their specificities.

lactase lactase a β-galactosidase occurring in the brush border membrane of the intestinal mucosa that catalyzes the cleavage of lactose to galactose and glucose; it is part of the β -glycosidase enzyme complex.

lactase deficiency alactasie reduced or absent lactase activity in the intestinal mucosa; the hereditary adult form is the normal state in most populations other than white Northern Europeans and may be characterized by abdominal pain, flatulence, and diarrhea after milk ingestion (lactose intolerance); the rare congenital form (congenital lactose intolerance) is characterized by diarrhea, vomiting, and failure to thrive.

lactate 1. lactate any salt or ester of lactic acid. 2. produire du lait to secrete milk.

L-lactate dehydrogenase (LDH) L-lactate déshydrogénase an enzyme that catalyzes the interconversion of lactate and pyruvate. It is widespread in tissues and is abundant in kidney, skeletal muscle, liver, and myocardium, appearing in elevated concentrations in the blood when these tissues are injured.

lactation lactation 1. the secretion of milk. 2. the period of milk secretion.

lacteal chylifère any of the intestinal lymphatics that transport chyle.

lactescence lactescence resemblance to milk.

lactic lactique pertaining to milk.

lactic acid acide lactique CH₃CHOHCOOH, a compound formed in the body in anaerobic metabolism of carbohydrate and also produced by bacterial action in milk. The sodium salt of racemic or inactive lactic acid (sodium lactate) is used as an electrolyte and fluid replenisher.

lacticacidemia lactacidémie lactacidemia.

lacticemia lacticémie lacticacidemia.

lactiferous lactifère conveying milk.

lactifuge lactifuge antigalactic.

lactigerous lactifère lactiferous.

lactim lactime see lactam.

lactitol lactitol a disaccharide analogue of lactulose used as a bulk sweetener; it is also laxative and is used to treat constipation.

lactivorous lactivore feeding or subsisting upon milk.

lact(o)- lact(o)- word element [L.], milk.

Lactobacillaceae Lactobacillaceae a family of gram-positive, non-spore-forming, rodshaped bacteria of the order Lactobacillales.

Lactobacillales Lactobacillales an order of lactic acid-producing bacteria of the class Bacilli that ferment sugars to produce energy.

Lactobacillus Lactobacillus a genus of the family Lactobacillaceae. They are anaerobic or microaerophilic and occur widely in nature and in the human mouth, vagina, and intestinal tract. In the oral cavity, they are found associated with dental caries but have no known etiologic role. Some produce only lactic acid and others produce other end products of fermentation. L. acidophilus L. acidophilus a lactobacillus producing the fermented product, acidophilus milk; preparations are used as digestive aids, for the production of B-complex vitamins, and to help prevent infections after antibiotic treatment.

lactobacillus lactobacille pl. lactobacilli an organism of the genus Lactobacillus.

lactocele lactocèle galactocele.

Lactococcus Lactococcus a genus of bacteria of the family Streptococcaceae, found in dairy products and sometimes in opportunistic infections.

lactogen lactogène any substance that enhances lactation. human placental l. l. placentaire humain a hormone secreted by the placenta; it has lactogenic, luteotropic, and growth-promoting activity, and inhibits maternal insulin activity.

lactogenic lactogène galactopoietic.

lactoglobulin lactoglobuline a globulin occurring in milk.

lactone lactone a cyclic organic compound in which the chain is closed by ester formation between a carboxyl and a hydroxyl group in the same molecule.

lacto-ovovegetarian lacto-ovo-végétarien ovolactovegetarian.

lactorrhea lactorrhée galactorrhea.

lactose lactose a disaccharide occurring in mammalian milk, which on hydrolysis yields glucose and galactose; used as a tablet and capsule diluent, a powder bulking agent, and as a component of infant feeding formulas.

lactoside lactoside glycoside in which the sugar constituent is lactose.

lactosuria lactosurie excessive lactose in the urine.

lactotrope lactotrope lactotroph.

lactotroph cellule lactrotope an acidophil of the adenohypophysis that secretes prolactin.

lactovegetarian lactovégétarien 1. one who practices lactovegetarianism. 2. pertaining to lactovegetarianism.

lactovegetarianism lactovégétarisme restriction of the diet to vegetables and dairy products, eschewing other foods of animal origin.

lactulose lactulose a synthetic disaccharide used as a laxative and to enhance excretion or formation of ammonia in the treatment of hepatic encephalopathy.

lacuna lacune pl. lacunae [L.] 1. a small pit or hollow cavity. 2. a defect or gap, as in the field of vision (scotoma). Adj.: lacunar. absorption l. l. d’absorption resorption l. bone l. l. osseuse a small cavity within the bone matrix, containing an osteocyte; from it slender canaliculi radiate and penetrate the adjacent lamellae to anastomose with the canaliculi of neighboring lacunae, thus forming a system of cavities interconnected by minute canals. cartilage l. l. de la matrice cartilagineuse any of the small cavities within the cartilage matrix, containing a chondrocyte. Howship l. l. de Howship resorption l. 1. intervillous l. intervilleuse, lacs sanguins maternels one of the blood spaces of the placenta in which the fetal villi are found. lateral lacunae espace parasinoïdal venous meshworks within the dura mater on either side of the superior sagittal sinus. osseous l. lacune osseuse bone l. l. pharyngis l. pharyngienne a depression at the pharyngeal end of the eustachian tube. resorption l. l. de résorption a pit or groove in developing bone that is undergoing resorption; frequently found to contain osteoclasts. trophoblastic l. l. du trophoblaste intervillous l.

lacunule lacunule a minute lacuna.

lacus lacus pl. lacus. [L.] lake.

lae- lae- for words beginning thus, see those beginning le-.

Laetrile Laetrile trademark for l-mandelonitrile-β-glucuronic acid, a semisynthetic derivative of amygdalin; it is alleged to have antineoplastic properties. Cf. laetrile.

laetrile laetrile amygdalin (l-mandelonitrile-β-gentiobioside) derived from crushed pits of certain fruits, usually apricots, and alleged to have antineoplastic properties. Cf. Laetrile.

laeve laeve [L.] nonvillous.

lag 1. période de latence the time between application of a stimulus and the reaction. 2. temps de latence the period after inoculation of bacteria into a culture medium, in which growth or cell division is slow. anaphase l. retard à l’anaphase delayed movement during anaphase of one homologous chromosome in mitosis or of one chromatid in meiosis, so that the chromosome is not incorporated into the nucleus of one of the daughter cells; the result is one normal cell and one cell with monosomy.

lagena lagœna 1. a part of the upper end of the cochlear duct. 2. the organ of hearing in nonmammalian vertebrates.

lageniform lagéniforme flask-shaped.

lagophthalmos lagophthalmie inability to shut the eyes completely.

lake 1. laquer to undergo separation of hemoglobin from erythrocytes. 2. lac a circumscribed collection of fluid in a hollow or depressed cavity. lacrimal l. lac lacrymal the triangular space at the medial angle of the eye, where the tears collect. marginal l’s lacs marginaux discontinuous venous lacunae, relatively free of villi, near the edge of the placenta, formed by merging of the marginal portions of the intervillous space with the subchorial lake.

lallation lallation a babbling, infantile form of speech.

lal(o)- lal(o)- word element [Gr.], speech; babbling.

laloplegia laloplégie logoplegia.

lalorrhea verbomanie logorrhea.

lambda lambda point of union of the lambdoid and sagittal sutures.

lambdoid lambdoïde shaped like the Greek letter lambda, Λ or Λ.

Lamblia Lamblia Giardia.

lame boiteux incapable of normal locomotion; deviating from normal gait.

lamella lamelle pl. lamellae [L.] 1. a thin leaf or plate, as of bone. 2. a medicated disk or wafer to be inserted under the eyelid. circumferential l. l. périphérique one of the layers of bone that underlie the periosteum and endosteum. concentric l. l. concentrique haversian l. endosteal l. l. endo-osseuse one of the bony plates lying beneath the endosteum. ground l. l. interstitielle interstitial l. haversian l. l. de Havers one of the concentric bony plates surrounding a haversian canal. intermediate l., interstitial l. l. intermédiaire one of the bony plates that fill in between the haversian systems. vitreous l. l. vitrée lamina basalis (1).

lamellar lamellaire 1. pertaining to or resembling lamellae. 2. lamellated (1).

lamellated lamelleux 1. having, composed of, or arranged in lamellae. 2. lamelliform.

lamelliform lamelliforme resembling lamellae.

lamellipodia lamellipodes sing. lamellipodium delicate sheetlike extensions of cytoplasm that form transient adhesions with the cell substrate and wave gently, enabling the cell to move along the substrate.

lamina lame pl. laminae [L.] 1. layer; a thin, flat plate of a larger composite structure. 2. l. of vertebra. basal l. l. basale 1. the layer of the basement membrane lying next to the basal surface of the adjoining cell layer, comprising two layers, the electron-lucent lamina lucida and the electron-dense lamina densa. 2. sometimes, the entire basement membrane. 3. l. basalis. l. basalis lamina basalis 1. one of the pair of longitudinal zones of the embryonic neural tube, from which develop the ventral gray columns of the spinal cord and the motor centers of the brain. 2. basal l. (1). l. basilaris lamina basiralis the posterior wall of the cochlear duct, separating it from the scala tympani. bony spiral l. l. spirale osseuse de la cochlée l. spiralis (def. 1). Bowman l. l. de Bowman see under membrane. l. choroidocapillaris l. choroïdocapillaire the inner layer of the choroid, composed of a single-layered network of small capillaries. l. cribrosa 1. lamina cibrosa fascia cribrosa. 2. lame (of ethmoid bone) the horizontal plate of ethmoid bone forming the roof of the nasal cavity, and perforated by many foramina for passage of olfactory nerves. 3. lame (of sclera) the perforated part of the sclera through which pass the axons of the retinal ganglion cells. l. densa lamina densa see basal l. (1). elastic l. l. élastique 1. Bowman membrane. 2. Descemet membrane. epithelial l. revêtement épendymaire du plexus choroïde the layer of ependymal cells covering the choroid plexus. l. lucida lamina lucida see basal l. (1). nuclear l. l. nucléaire a tightly woven meshwork that lines the nuclear side of the inner nuclear membrane; it is believed to control the shape of the nucleus and mediates interaction between the inner nuclear membrane and chromatin. l. propria lamina propria 1. the connective tissue layer of mucous membrane. 2. the middle fibrous layer of the tympanic membrane. l. rara lamina rara lamina lucida; see basal l. (1). In the lung alveoli and renal glomeruli, one may occur on each side of the lamina densa. reticular l. l. réticulaire 1. a layer of the basement membrane, adjacent to the connective tissue, seen in some epithelia. 2. l. reticularis. l. reticularis lamina reticularis the perforated hyaline membrane covering the organ of Corti. Rexed laminae, spinal laminae lamination de Rexed an architectural scheme used to classify the structure of the spinal cord, based on the cytological features of the neurons in different regions of the gray substance; it consists of nine laminae (I-IX) that extend throughout the cord and a tenth region (X) that surrounds the central canal. l. spiralis l. spirale osseuse 1. a double plate of bone winding spirally around the modiolus, dividing the spiral canal of the cochlea into the scala tympani and scala vestibuli. 2. a bony projection on the outer wall of the cochlea in the lower part of the first turn. terminal l. of hypothalamus l. terminale de l’hypothalamus the thin plate derived from the telencephalon, forming the anterior wall of the third ventricle of the cerebrum. l. of vertebra, l. of vertebral arch pédicule vertébral either of the pair of broad plates of bone flaring out from the pedicles of the vertebral arches and fusing together at the midline to complete the posterior part of the arch and provide a base for the spinous process.

laminagraphy laminagraphie tomography.

laminaplasty laminoplastie relief of compression of the spinal cord or nerve roots by incision completely through one lamina of a vertebral arch, creation of a trough in the contralateral lamina, and opening of the arch like a door.

laminar laminaire 1. pertaining to a lamina or laminae. 2. laminated. 3. of, pertaining to, or being a streamlined, smooth fluid flow.

laminated stratifié having, composed of, or arranged in layers or laminae.

laminectomy laminectomie excision of the posterior arch of a vertebra.

laminotomy laminotomie transection of a lamina of a vertebra.

lamivudine lamivudine a nucleoside analogue that inhibits reverse transcriptase, used as an antiviral agent in the treatment of chronic hepatitis B and, in combination with zidovudine, the treatment of HIV infection and AIDS.

lamotrigine lamotrigine an anticonvulsant used in the treatment of certain forms of epilepsy; also used to stabilize mood in bipolar I disorder.

lamp lampe an apparatus for furnishing heat or light. mercury arc l., mercury vapor l., quartz l. l. à vapeur de mercure one in which the arc is in mercury vapor, enclosed in a quartz burner; used in photodynamic therapy; it may be air- or water-cooled. slit l. l. à fente one having a diaphragm with a slitlike opening through which a narrow flat beam of intense light may be projected into the eye for microscopic study of the conjunctivae, cornea, iris, lens, and vitreous. sun l. l. solaire a lamp that gives off radiation, especially ultraviolet, in ranges similar to those of the sun’s rays. Wood l. l. de Wood a medium-pressure mercury arc lamp that transmits Wood light for diagnosis of skin conditions such as erythrasma and fungus infections, as well as porphyrins or fluorescent minerals in the skin, scalp, and hair. xenon arc l. l. à arc au xénon one producing light of high intensity in a wide continuum of wavelengths; used with optical filters to simulate solar radiation.

lance 1. lancette lancet. 2. inciser avec une lancette to cut or incise with a lancet.

lancet lancette a small, pointed, two-edged surgical knife.

lancinating lancinant tearing, darting, or sharply cutting; said of pain.

lanolin lanoline a purified, waxlike substance from the wool of sheep, Ovis aries, occurring in an anhydrous form and also a form containing 25 to 30 percent water; used as a water-in-oil ointment or cream base. Modified l. has been additionally processed to reduce the amount of free lanolin alcohols and detergent and pesticide residues.

lansoprazole lansoprazole a proton pump inhibitor used to inhibit gastric acid secretion for the treatment of duodenal or gastric ulcer, gastroesophageal reflux disease, and hyperchlorhydria.

lanthanum (La) lanthane chemical element (see Table of Elements), at. no. 57.

lanugo lanugo the fine hair on the body of the fetus.

lapar(o)- lapar(o)- word element [Gr.], loin or flank; loosely, abdomen.

laparohysterectomy laparohystérectomie abdominal hysterectomy.

laparohysterotomy laparohystérotomie abdominal hysterotomy.

laparoscope laparoscope an endoscope for examining the peritoneal cavity.

laparoscopy laparoscopie examination or treatment of the interior of the abdomen by means of a laparoscope.

laparotomy laparotomie incision through the abdominal wall.

lapinization lapinisation serial passage of a virus or vaccine through rabbits to modify its characteristics.

lard arlonge purified internal fat of the abdomen of the hog.

larva larve pl. larvae [L.] an independent, motile, sometimes feeding, developmental stage in the life history of an animal. l. currens larva currens a variant of larva migrans caused by Strongyloides stercoralis, in which the progression of the linear lesion is much more rapid. cutaneous l. migrans l. migrans cutanée creeping eruption; larva migrans in the skin, characterized by thin, curving, pruritic lines corresponding to the subcutaneous movements of the parasitic hookworm larvae. l. migrans l. migrans 1. a life stage of certain parasitic larvae in which they wander through the body of their host. 2. infestation of a human or other animal by such a wandering parasitic larva. ocular l. migrans l. migrans oculaire infection of the eye with larvae of Toxocara canis or T. cati, which may lodge in the choroid or retina or migrate to the vitreous; on the death of the larvae, a granulomatous inflammation occurs, the lesion varying from a translucent elevation of the retina to massive retinal detachment and pseudoglioma. visceral l. migrans l. migrans viscérale a condition due to prolonged migration of nematode larvae in human tissue other than skin; commonly caused by the larvae of Toxocara canis or T. cati, which do not complete their life cycle in humans.

larvate larvé masked; concealed; said of a disease or symptom of disease.

laryngeal laryngé pertaining to the larynx.

laryngectomy laryngectomie surgical removal of the larynx.

laryngismus laryngisme laryngospasm. Adj.: laryngismal. l. stridulus laryngismus stridulus pseudocroup; sudden laryngeal spasm with crowing inhalation and cyanosis, usually seen in children at night.

laryngitis laryngite inflammation of the larynx. Adj.: laryngitic. subglottic l. l. sous-glottique inflammation of the undersurface of the vocal cords.

laryng(o)- laryng(o)- word element [Gr.], larynx.

laryngocele laryngocèle a congenital anomalous air sac communicating with the cavity of the larynx, which may bulge outward on the neck.

laryngofissure laryngofissure median laryngotomy.

laryngography laryngographie radiography of the larynx.

laryngology laryngologie the branch of medicine dealing with the throat, pharynx, larynx, nasopharynx, and tracheobronchial tree.

laryngopathy laryngopathie any disorder of the larynx.

laryngopharyngeal laryngopharyngien pertaining to the larynx and pharynx or to the laryngopharynx.

laryngopharyngectomy laryngopharyngectomie excision of the larynx and pharynx.

laryngopharynx laryngopharynx the portion of the pharynx below the upper edge of the epiglottis, opening into the larynx and esophagus. Adj.: laryngopharyngeal.

laryngophony laryngophonie a voice sound heard over the larynx.

laryngoplasty laryngoplastie plastic repair of the larynx.

laryngoplegia laryngoplégie paralysis of the larynx.

laryngoptosis laryngoptose lowering and mobilization of the larynx as sometimes seen in the aged.

laryngoscopy laryngoscopie visual examination of the interior larynx. Adj.: laryngoscopic.

laryngospasm laryngospasme spasmodic closure of the larynx.

laryngostenosis laryngosténose narrowing or stricture of the larynx.

laryngostomy laryngostomie surgical fistulization of the larynx.

laryngotomy laryngotomie incision of the larynx. inferior l. l. inférieure laryngotomy through the cricothyroid membrane. median l. l. médiane laryngotomy through the thyroid cartilage. subhyoid l, superior l. l. sous-hyoïdienne laryngotomy through the thyrohyoid membrane.

laryngotracheitis laryngotrachéite inflammation of the larynx and trachea.

laryngotracheotomy laryngotrachéotomie incision of the larynx and trachea.

larynx larynx pl. larynges [L.] the organ of voice; the air passage between the lower pharynx and the trachea, containing the vocal cords and formed by nine cartilages: the thyroid, cricoid, and epiglottis and the paired arytenoid, corniculate, and cuneiform cartilages. See Plate 25.

laser laser a device that transfers light of various frequencies into an extremely intense, small, and nearly nondivergent beam of monochromatic radiation in the visible region, with all the waves in phase; capable of mobilizing immense heat and power when focused at close range, it is used as a tool in surgery, in diagnosis, and in physiologic studies. argon l. l. argon a laser with ionized argon as the active medium, whose beam is in the blue and green visible light spectrum; used for photocoagulation. carbon-dioxide l. l. à dioxyde de carbone a laser with carbon dioxide gas as the active medium, which produces infrared radiation at 10,600 nm; used to excise and incise tissue and to vaporize. dye l. l. à colorant a laser with organic dye as the active medium, whose beam is in the visible light spectrum. excimer l. l. à excimère a laser with rare gas halides as the active medium, whose beam is in the ultraviolet spectrum and penetrates tissues only a short distance; used in ophthalmological procedures and laser angioplasty. helium-neon l. l. à héliumnéon a laser with a mixture of ionized helium and neon gases as the active medium, whose beam is in the red visible light spectrum; used as a guiding beam for lasers operating at nonvisible wavelengths. krypton l. l. à krypton a laser with krypton ionized by electric current as the active medium, whose beam is in the yellow-red visible light spectrum; used for photocoagulation. KTP l. l. KTP one in which a beam generated by a neodymium:YAG laser is directed through a potassium titanyl phosphate crystal to produce a beam in the green visible spectrum; used for photoablation and photocoagulation. neodymium:yttrium-aluminum-garnet (Nd:YAG) l. l. néodyme:yttriumaluminium- grenat (Nd:YAG) a laser whose active medium is a crystal of yttrium, aluminum, and garnet doped with neodymium ions, and whose beam is in the near infrared spectrum at 1060 nm; used for photocoagulation and photoablation. potassium titanyl phosphate l. l. potassium- titanyl-phosphate KTP l. pulsed dye l. l. à colorant pulsé a dye laser in which excitation of the dye by pulses of intense light from a flashlamp produces a beam in the yellow visible light spectrum, with alternating on and off phases of a few microseconds each; used to decolorize pigmented lesions. tunable dye l. l. à colorant accordable a dye laser whose active medium can be altered so that the beam has any of several wavelengths.

LASIK LASIK laser-assisted in-situ keratomileusis.

lassitude lassitude weakness; exhaustion.

latanoprost latanoprost an antiglaucoma agent applied topically to the conjunctiva in the treatment of open-angle glaucoma and ocular hypertension.

latency latence 1. a state of seeming inactivity. 2. the time between the instant of stimulation and the beginning of a response. 3. see under stage.

latent latent concealed; not manifest; potential; dormant; quiescent.

latentiation mise en latence the process of making latent; in pharmacology, chemical modification of a biologically active compound to affect its absorption, distribution, etc., the modified compound being transformed after administration to the active compound by biological processes.

laterad laterad toward the lateral aspect.

lateral latéral 1. denoting a position farther from the median plane or midline of the body or a structure. 2. pertaining to a side.

lateralis lateralis [L.] lateral.

laterality latéralité a tendency to use preferentially the organs (hand, foot, ear, eye) of the same side in voluntary motor acts. crossed l. l. croisée the preferential use of contralateral members of the different pairs of organs in voluntary motor acts, e.g., right eye and left hand. dominant l. l. dominante lateral dominance.

laterodorsal latérodorsal denoting a position farther from the median plane or midline and more toward the back surface.

lateroduction latéroduction movement of an eye to either side.

lateroflexion latéroflexion flexion to one side.

laterotorsion latérotorsion twisting of the vertical meridian of the eye to either side.

lateroversion latéroversion abnormal turning to one side.

latex latex a viscid, milky juice secreted by some seed plants.

lathyrism lathyrisme spastic paraplegia, pain, hyperesthesia, and paresthesia due to excessive ingestion of the seeds of leguminous plants of the genus Lathyrus, which includes many kinds of peas. Adj.: lathyritic.

latissimus latissimus [L.] widest; in anatomy, denoting a broad structure.

latrodectism latrodectisme intoxication due to venom of spiders of the genus Latrodectus.

Latrodectus Latrodectus a genus of poisonous spiders, including L. mactans, the black widow spider, whose bite may cause severe symptoms or even death.

LATS LATS long-acting thyroid stimulator.

latus latus [L.] broad, wide.

latus latus pl. latera [L.] the side or flank.

laurate laurate a salt, ester, or anionic form of lauric acid.

lauric acid acide laurique a twelve-carbon saturated fatty acid found in many vegetable fats, particularly coconut oil and palm kernel oil.

lavage lavage 1. the irrigation or washing out of an organ, as of the stomach or bowel. 2. to wash out, or irrigate.

lavender lavande 1. any plant of the genus Lavandula. 2. a preparation of the flowers of L. angustifolia or of the lavender oil extracted from them; used for loss of appetite, dyspepsia, nervousness, and insomnia; also widely used in folk medicine.

law loi a uniform or constant fact or principle. Allen’s l. l. d’Allen the more sugar a normal person is given the more is utilized; the reverse is true in diabetics. all-or-none l. l. du « tout ou rien » see all or none. Beer’s l, Beer-Lambert l. l. de Lambert in spectrophotometry, the absorbance of a solution is proportional to the concentration of the absorbing solute and to the path length of the light beam through the solution. Boyle’s l. l. de Boyle at a constant temperature the volume of a perfect gas varies inversely as the pressure, and the pressure varies inversely as the volume. Charles’ l. l. de Charles at a constant pressure the volume of a given mass of a perfect gas varies directly with the absolute temperature. l. of conservation of energy l. de la conservation de l’énergie in any given system the amount of energy is constant; energy is neither created nor destroyed, but only transformed from one form to another. l. of conservation of mass, l. of conservation of matter l. de la conservation de masse mass (or matter) can be neither created nor destroyed; this law can be violated on the microscopic level. Dalton’s l. l. de Dalton the pressure exerted by a mixture of nonreacting gases is equal to the sum of the partial pressures of the separate components; it holds true only at very low pressures. Hellin’s l, Hellin-Zeleny l. l. de Hellin one in about 89 pregnancies ends in the birth of twins; one in 89 × 89 (7921), of triplets; one in 89 × 89 × 89 (704,969), of quadruplets. Henry’s l. l. d’ Henry the solubility of a gas in a liquid solution at a constant temperature is proportional to the partial pressure of the gas above the solution. l. of independent assortment l. d’assortiment indépendant genes that are not alleles are distributed to the gametes independently of one another; one of Mendel’s laws. Mendel’s l’s, mendelian l’s l. de Mendel two laws of inheritance of single-gene traits that form the basis of genetics; the law of segregation and the law of independent assortment. Nysten’s l. l. de Nysten rigor mortis affects first the muscles of mastication, next those of the face and neck, then those of the trunk and arms, and last those of the legs and feet. Ohm’s l. l. d’Ohm the strength of an electric current varies directly as the electromotive force and inversely as the resistance. Raoult’s l. l. de Raoult the vapor pressure of a volatile component of an ideal solution is equal to the mole fraction of that substance in solution times its vapor pressure in the pure state at the temperature of the solution; it is true only for ideal solutions and ideal gases. l. of segregation l. de ségrégation the members of a pair of allelic genes segregate from one another and pass to different gametes; one of Mendel’s laws. l. of similars l. des semblables in homeopathy, the principle that a substance that in large doses will produce symptoms of a specific disease will, in extremely small doses, cure it. l’s of thermodynamics l. de la thermodynamique Zeroth law: two systems in thermal equilibrium with a third are in thermal equilibrium with each other. First law: energy is conserved in any process. Second law: there is always an increase in entropy in any naturally occurring (spontaneous) process. Third law: absolute zero is unattainable.

lawrencium (Lr) lawrencium chemical element (see Table of Elements), at. no. 103.

laxative laxatif 1. mildly cathartic. 2. a cathartic or purgative. bulk l., bulk-forming l. l. de lest one promoting bowel evacuation by increasing fecal volume. contact l. l. de contact one that increases the motor activity of the intestinal tract. lubricant l. l. lubrifiant one that promotes softening of the stool and facilitates passage of the feces through the intestines by its lubricant effect. saline l. l. salin a salt administered in hypertonic solution to draw water into the intestinal lumen by osmosis, distending it and promoting peristalsis and evacuation. stimulant l. l. stimulant contact l.

laxity laxité 1. slackness or looseness; a lack of tautness, firmness, or rigidity. 2. slackness or displacement in the motion of a joint. Adj.: lax.

layer couche a stratum or lamina. ameloblastic l. c. améloblastique the inner layer of cells of the enamel organ, which forms the enamel prisms of the teeth. bacillary l. c. bacillaire l. of rods and cones. basal l. c. basale stratum basale. basal cell l. c. cellulaire basale the stratum basale of the epidermis. blastodermic l. feuillet blastodermique germ l. l’s of cerebral cortex c. du cortex cérébral six anatomical divisions (I-VI) of the cerebral cortex (specifically the neocortex), distinguished according to the types of cells and fibers they contain. clear l. c. claire stratum lucidum. columnar l. c. cylindrique mantle l. compact l. of endometrium c. compacte de l’endomètre stratum compactum. enamel l. c. de l’émail either of two walls, the inner concave wall or the outer convex wall, of the enamel organ. functional l. of endometrium c. fonctionnelle de l’endomètre stratum functionale. ganglionic l. of cerebellum c. des cellules ganglionnaires du cervelet Purkinje l. germ l. c. germinale, feuillet embryonnaire any of the three primary layers of cells of the embryo (ectoderm, endoderm, and mesoderm), from which the tissues and organs develop. germinative l. c. germinative stratum germinativum. granular l. c. granuleuse 1. stratum granulosum. 2. the deep layer of the cortex of the cerebellum. half-value l. c. de demi-atténuation the thickness of a given substance that, when introduced in the path of a given beam of rays, will reduce its intensity by one half. Henle l. c. de Henle the outermost layer of the inner root sheath of the hair follicle. horny l. c. cornée stratum corneum. malpighian l. c. de Malpighi stratum germinativum. mantle l. c. du manteau the middle layer of the wall of the primordial neural tube, containing primordial nerve cells and later forming the gray matter of the central nervous system. marginal l. c. marginale the outermost layer of the wall of the primordial neural tube, a fibrous mesh into which the nerve fibers later grow, forming the white matter of the central nervous system. odontoblastic l. c. odontoblastique the epithelioid layer of odontoblasts in contact with the dentin of teeth. prickle cell l. c. des cellules à épines stratum spinosum. Purkinje l. c. de Purkinje the layer of Purkinje neurons situated between the external molecular layer and the internal granular layer of the cerebellar cortex. l. of rods and cones c. des cônes et des bâtonnets a layer of the retina, located between the pigmented part and the external limiting membrane, containing the sensory elements, the rods and cones. spinous l. c. des cellules épineuses stratum spinosum. spongy l. of endometrium c. spongieuse de l’endomètre stratum spongiosum. subendocardial l. c. sous-endocardiaque the layer of loose fibrous tissue uniting the endocardium and myocardium and containing the vessels and nerves of the conducting system of the heart. subepicardial l. c. sous-épicardique the layer of loose connective tissue uniting the epicardium and myocardium.

lb lb [L.] pound (L. libra).

LBBB LBBG left bundle branch block; see bundle branch block, under block.

LCAT LCAT lecithin-cholesterol acyltransferase.

LCIS LCIS lobular carcinoma in situ.

LD₅₀ LD₅₀ median lethal dose.

LDH LDH l-lactate dehydrogenase.

LDL LDL low-density lipoprotein.

LDL-C LDL-C low-density-lipoprotein cholesterol.

L-dopa L-dopa levodopa.

LE LE left eye; lupus erythematosus.

lead (Pb) plomb chemical element (see Table of Elements), at. no. 82. Absorption or ingestion causes poisoning, which affects the brain, nervous and digestive systems, and blood.

lead dérivation any of the conductors connected to the electrocardiograph, each comprising two or more electrodes that are attached at specific body sites and used to examine electrical activity by monitoring changes in the electrical potential between them. l. I D I the standard bipolar limb lead attached to the right and left arms. l. II D II the standard bipolar limb lead attached to the right arm and left leg. l. III D III the standard bipolar limb lead attached to the left arm and left leg. augmented unipolar limb l. d. unipolaire périphérique augmentée a modified unipolar limb lead; the three standard leads are: aV_F (left leg), aV_L (left arm), and aV_R (right arm). aV_F l. d. aV_F an augmented unipolar limb lead in which the positive electrode is on the left leg. aV_L l. d. aV_L an augmented unipolar limb lead in which the positive electrode is on the left arm. aV_R l. d. aV_R an augmented unipolar limb lead in which the positive electrode is on the right arm. bipolar l. d. bipolaire an array involving two electrodes placed at different body sites. limb l. d. périphérique an array in which any registering electrodes are attached to limbs. pacemaker l., pacing l. d. du stimulateur cardiaque the connection between the heart and the power source of an artificial cardiac pacemaker. precordial l’s d. précordiales leads in which the exploring electrode is placed on the chest and the other is connected to one or more limbs; usually used to denote one of the V leads. standard l’s d. standard the 12 leads used in a standard electrocardiogram, comprising the standard bipolar limb leads I-III, the augmented unipolar limb leads, and the standard precordial leads. unipolar l. d. unipolaire an array of two electrodes, only one of which transmits potential variation. V l’s d. V the series of six standard unipolar leads in which the exploring electrode is attached to the chest, designated V₁ to V₆. XYZ l’s d. XYZ leads used in one system of spatial vectorcardiography.

learning apprentissage a long-lasting adaptive behavioral change due to experience. latent l. a. latent that which occurs without reinforcement, becoming apparent only when a reinforcement or reward is introduced.

lecithal lécithe having a yolk; used especially as a word termination (isolecithal, etc.).

lecithin lécithine phosphatidylcholine.

lecithin-cholesterol acyltransferase (LCAT) lécithine- cholestérol acyltransférase transférase an enzyme that catalyzes the formation of cholesteryl esters in high-density lipoproteins; deficiency of enzyme activity, an inherited disorder, results in accumulation of cholesterol and phosphatidylcholine in plasma and tissues, which causes corneal opacities, anemia, and often proteinuria.

lectin lectine any of a group of hemagglutinating proteins found primarily in plant seeds, which bind specifically to the branching sugar molecules of glycoproteins and glycolipids on the surface of cells.

leech sangsue any of the annelids of the class Hirudinea, especially Hirudo medicinalis; some species are bloodsuckers. Leeches have been used for drawing blood.

leflunomide léflunomide an immunomodulator used in treatment of rheumatoid arthritis.

leg jambe 1. the part of the lower limb between the knee and ankle. 2. in common usage, the entire lower limb, with the part below the knee being called the lower leg. 3. patte any of the four limbs of a quadruped. bandy l. j. arquée bowleg. bayonet l. j. en baïonnette ankylosis of the knee after backward displacement of the tibia and fibula. bow l. j. arquée see bowleg. milk l. œdème blanc douloureux phlegmasia alba dolens. restless l’s syndrome des j. sans repos a disagreeable, creeping, irritating sensation in the legs, usually the lower legs, relieved only by walking or keeping the legs moving. scissor l. j. en ciseaux deformity with crossing of the legs in walking.

Legionella Legionella a genus of gram-negative, aerobic, rod-shaped bacteria of the family Legionellaceae, normal inhabitants of lakes, streams, and moist soil; they have often been isolated from cooling-tower water, evaporative condensers, tap water, shower heads, and treated sewage. L. micdadei is the causative agent of Pittsburgh pneumonia. L. pneumophila is the causative agent of legionnaires’ disease.

Legionellaceae Legionellaceae a family of gram-negative, aerobic, non-spore-forming, rod-shaped bacteria of the order Legionellales.

Legionellales Legionellales an order of bacteria of the class Gammaproteobacteria, whose members are intracellular parasites.

legionellosis légionellose disease caused by infection with Legionella pneumophila; see legionnaires’ disease and Pontiac fever.

legume légume 1. any plant of the large family Leguminosae. 2. the pod or fruit of one of these plants, such as a pea or bean.

leiomyofibroma léiomyofibrome leiomyoma.

leiomyoma léiomyome a benign tumor derived from smooth muscle. l. cutis leiomyoma cutis one or more smooth, firm, painful, often waxy nodules arising from cutaneous or subcutaneous smooth muscle fibers. epithelioid l. l. épithélioïde leiomyoma, usually of the stomach, in which the cells are polygonal rather than spindle shaped. l. uteri, uterine l. leiomyoma uteri leiomyoma of the uterus, the most common of all tumors found in women; it is usually in the body of the organ but may be elsewhere.

leiomyomatosis léiomyomatose the occurrence of multiple leiomyomas throughout the body.

leiomyosarcoma léiomyosarcome a sarcoma containing spindle cells of smooth muscle.

Leishmania Leishmania a genus of parasitic protozoa, including several species pathogenic for humans; divided into two subgenera, Leishmania and Viannia, based on development in the sandfly vector; with species in the latter restricted to the New World. Species and complexes have been distinguished on the basis of geographic origin, clinical syndrome produced, and ecologic characteristics, or on the basis of association with specific leishmaniases, but increasingly are separated by phylogenetic relationships. Important pathogenic species include L. donovani, L. infantum, L. major, L. tropica, L. mexicana, and L. braziliensis. Adj.: leishmanial.

leishmaniasis leishmaniose infection with Leishmania. cutaneous l. l. cutanée any of the types that have cutaneous symptoms, often disfiguring; distinguished as either the Old World form caused mainly by Leishmania major, L. tropica or L. aethiopica and the New World form caused mainly by L. mexicana, L. amazonensis, or L. braziliensis. diffuse cutaneous l. l. cutanée diffuse a variant of cutaneous leishmaniasis in which a localized, nonulcerative lesion disseminates to form multiple cutaneous nodules or plaques resistant to treatment; usually occurring in immunocompromised patients and associated with Leishmania amazonensis, L. mexicana, or L. aethiopica. mucocutaneous l. l. cutanéomuqueuse a form in which a primary cutaneous lesion is followed by secondary mucosal involvement, causing widespread destruction of tissue with marked deformity; occurring in the New World and usually caused by Leishmania braziliensis. post-kala-azar dermal l. l. dermique post-kala-azar a condition associated with visceral leishmaniasis, characterized by hypopigmented or erythematous macules on the face and sometimes also the trunk and limbs, the facial lesions progressing to papules and nodules resembling those of lepromatous leprosy; usually caused by Leishmania donovani. l. recidivans leishmaniasis recidivans a prolonged, relapsing form of cutaneous leishmaniasis resembling lupus vulgaris; usually caused by Leismania tropica in the Old World and occasionally by L. braziliensis in the New World. visceral l. l. viscérale a chronic infectious disease, highly fatal if untreated, caused by Leishmania donovani, characterized by hepatosplenomegaly, fever, chills, vomiting, anemia, leukopenia, hypergammaglobulinemia, and a gray color to the skin.

-lemma -lemma word element [Gr.], sheath.

lemmoblastic lemmoblastique forming or developing into neurilemma tissue.

lemniscus lemniscus pl. lemnisci [L.] 1. a ribbon or band. 2. a band or bundle of fibers in the central nervous system.

length (l ) longueur the longest dimension of an object, or of the measurement between the two ends. crown-heel l. (CHL) l. vertex-talon the distance from the crown of the head to the heel in embryos, fetuses, and infants; the equivalent of standing height in older persons. crown-rump l. (CRL) l. vertex-coccyx the distance from the crown of the head to the breech in embryos, fetuses, and infants; the equivalent of sitting height in older persons. focal l. l. focale the distance between a lens and an object from which all rays of light are brought to a focus.

lens 1. lentille a piece of glass or other transparent material so shaped as to converge or scatter light rays; see also glasses. 2. cristallin crystalline l.; the transparent, biconvex body separating the posterior chamber and vitreous body, and constituting part of the refracting mechanism of the eye; see Plate 30. achromatic l. l. achromatique one corrected for chromatic aberration. aplanatic l. l. aplanétique one for correcting spherical aberrations. bandage l. l. pansement a soft contact lens worn on a diseased or injured cornea to protect or treat it. biconcave l. l. biconcave one concave on both faces. biconvex l. l. biconvexe one convex on both faces. bifocal l. l. bifocale, verre à double foyer one with two parts of different refracting powers, the upper for distant and the lower for near vision. concavoconvex l. l. concavo- convexe one with one concave and one convex face. contact l. l. de contact a curved shell of glass or plastic applied directly over the globe or cornea to correct refractive errors. It may be a soft (hydrophilic) contact l., flexible and water absorbent, or a hard (hydrophobic) contact l., rigid and not water absorbent; the latter type is subdivided into gas permeable and non-gas permeable, usually polymethylmethacrylate (PMMA), lenses. convexoconcave l. l. convexo-concave one with one convex and one concave face. crystalline l. cristallin lens (2). cylindrical l. l. cylindrique one for correcting astigmatism, with one plane surface and one cylindrical, or one spherical surface and one toroidal. Symbol C. decentered l. l. décentrée one whose optical axis does not pass through the center. honeybee l. l. à facettes a magnifying lens resembling the multifaceted eye of the honeybee, consisting of three or six small telescopes mounted in the upper part of the lens and directed toward the center and right and left visual fields. Prisms are included to provide a continuous, unbroken magnified field of view. omnifocal l. verre à foyer progressif one whose power increases continuously and regularly in a downward direction, avoiding the discontinuity of bifocal and trifocal lenses. planoconvex l. l. plan-convexe a lens with one plane and one convex side. spherical l. (S, sph) l. sphérique one that is a segment of a sphere. trial l. verre d’essai one used to test vision. trifocal l. l. trifocale, verre à triple foyer one with three parts of different refracting powers, the upper for distant, the middle for intermediate, and the lower for near vision.

lenticonus lenticône a congenital conical bulging, anteriorly or posteriorly, of the lens of the eye.

lenticular lenticulaire 1. pertaining to or shaped like a lens. 2. cristallinien pertaining to the lens of the eye. 3. pertaining to the lenticular nucleus.

lentiform lentiforme lens-shaped.

lentigines lentigines plural of lentigo.

lentiginosis lentiginose a condition marked by multiple lentigines. progressive cardiomyopathic l. l. cardiomyopathique progressive multiple symmetrical lentigines, hypertrophic obstructive cardiomyopathy, and retarded growth, sometimes with mental retardation.

lentiglobus lentiglobus exaggerated curvature of the lens of the eye, producing an anterior spherical bulging.

lentigo lentigo pl. lentigines [L.] a flat brownish pigmented spot on the skin, due to increased deposition of melanin and an increased number of melanocytes. l. maligna l. malin a circumscribed macular patch of hyperpigmentation, with shades of brown or black, that enlarges slowly and may be a precursor to malignant melanoma. senile l., l. senilis l. sénile solar l. l. simplex l. simple the most common type, found on mucous membranes and skin, usually associated with a congenital syndrome. solar l. l. solaire a benign, discrete, type found on chronically sun-exposed skin in light-skinned adults, such as the forehead or back of the hand.

Lentivirus Lentivirus a genus of retroviruses that cause persistent infection that typically results in chronic, progressive, usually fatal disease; it includes the human immunodeficiency viruses.

lentivirus lentivirus any virus of the subfamily Lentivirinae.

leontiasis léontiasis leonine facies. l. ossea, l. ossium l. ossea leonine facies due to hypertrophy of the bones of the cranium and face.

leper lépreux a person with leprosy; a term now in disfavor.

lepirudin lépirudine a recombinant form of hirudin used as an anticoagulant in patients with heparin-induced thrombocytopenia.

lepra lepra leprosy.

leprechaunism lepréchaunisme a lethal familial condition in which an infant is small, has elfin facies, and has endocrine disorders such as enlargement of the clitoris in girls or of the penis in boys.

leproma léprome a superficial granulomatous nodule rich in Mycobacterium leprae, the characteristic lesion of lepromatous leprosy.

lepromatous lépromateux pertaining to or containing lepromas; see lepromatous leprosy, under leprosy.

lepromin lépromine a repeatedly boiled, autoclaved, gauze-filtered suspension of finely triturated lepromatous tissue and leprosy bacilli, used in the skin test for tissue resistance to leprosy.

leprostatic léprostatique inhibiting the growth of Mycobacterium leprae, or an agent that so acts.

leprosy lèpre a chronic communicable disease caused by Mycobacterium leprae and characterized by the production of granulomatous lesions of the skin, mucous membranes, and peripheral nervous system. Two principal, or polar, types are recognized: lepromatous and tuberculoid. Adj.: leprotic, leprous. lepromatous l. l. lépromateuse that form marked by the development of lepromas and by an abundance of leprosy bacilli from the onset; nerve damage occurs only slowly, and the skin reaction to lepromin is negative. It is the only form that regularly serves as a source of infection. tuberculoid l. l. tuberculoïde the form in which leprosy bacilli are few or lacking and nerve damage occurs early, so that all skin lesions are denervated from the onset, often with dissociation of sensation; the skin reaction to lepromin is positive, and the patient is rarely a source of infection to others.

lept(o)- lept(o)- word element [Gr.], slender; delicate.

leptocephalus leptocéphale a person with an abnormally tall, narrow skull.

leptocyte leptocyte target cell (1).

leptomeninges leptoméninges sing. leptomeninx the pia mater and arachnoid taken together; the pia-arachnoid. Adj.: leptomeningeal.

leptomeningitis leptoméningite inflammation of the leptomeninges.

leptomeningopathy leptoméningite any disease of the leptomeninges.

leptomonad Leptomonas of or pertaining to Leptomonas.

Leptomonas Leptomonas a genus of protozoa of the family Trypanosomatidae, parasitic in the digestive tract of insects.

leptomonas leptomonas any protozoan of the genus Leptomonas.

leptopellic leptopellique having a narrow pelvis.

Leptospira Leptospira a genus of aerobicspirochete bacteria of the family Leptospiraceae; all pathogenic strains (i.e., those that cause leptospirosis) are contained in the species L. interrogans, which is divided into several serogroups, which are in turn divided into serovars.

leptospira leptospira an individual organism belonging to the genus Leptospira. Adj.: leptospiral.

Leptospiraceae Leptospiraceae a family of aerobic bacteria of the order Spirochaetales, consisting of flexible helical cells.

leptospirosis leptospirose any infectious disease due to a serovar of Leptospira interrogans, manifested by lymphocytic meningitis, hepatitis, and nephritis, separately or in combination; types vary in severity from a mild carrier state to fatal disease.

leptotene leptotène the first stage of prophase in meiosis I, in which the chromosomes are threadlike.

lesbian lesbienne 1. pertaining to homosexuality between women. 2. a female homosexual.

lesbianism lesbianisme homosexuality between women.

lesion lésion any pathological or traumatic discontinuity of tissue or loss of function of a part. angiocentric immunoproliferative l. l. immunoproliférative angiocentrique a multisystem disease consisting of invasion and destruction of body tissues and structures by atypical lymphocytoid and plasmacytoid cells resembling a lymphoma, often progresssing to lymphoma. Armanni-Ebstein l. l. d’Armanni-Ebstein vacuolization of the renal tubular epithelium in diabetes. benign lymphoepithelial l. l. lymphoépithéliale bénigne enlargement of salivary glands with infiltration of parenchyma by polyclonal B and T cells, atrophy of acini, and formation of lymphoepithelial islands. Blumenthal l. l. de Blumenthal a proliferative vascular lesion in the smaller arteries in diabetes. bull’s-eye l. en œil de boeuf 1. a shadow seen on a radiogram, usually of the duodenal wall, with a dark circle surrounding a central light circle; it represents tumor metastasis in which a mass has central ulceration. 2. target l. (3). central l. l. centrale any lesion of the central nervous system. Ghon primary l. l. primaire de Ghon Ghon focus. Janeway l. l. de Janeway a small erythematous or hemorrhagic lesion, usually on the palms or soles, in bacterial endocarditis. Kimmelstiel-Wilson l. l. de Kimmelstiel-Wilson a microscopic, spherical, hyaline mass surrounded by capillaries, found in the kidney glomerulus in the nodular form of intercapillary glomerulosclerosis. primary l. l. primaire the original lesion manifesting a disease, as a chancre. skip l. l. discontinue a lesion that is discontinuous; the most common occurrence is in two different segments of intestine affected by inflammatory bowel disease. target l. l. cible 1. bull’s-eye lesion. 2. a small, circumscribed focus of necrosis with a gray center surrounded by erythema, seen in the lungs in invasive aspergillosis. 3. a skin lesion characteristic of erythema multiforme, having a central bulla or crust surrounded by concentric zones of changed colors.

lethal létal fatal.

lethargy léthargie 1. a lowered level of consciousness, with drowsiness, listlessness, and apathy. 2. a condition of indifference.

letrozole létrozole an antineoplastic used in the treatment of advanced breast cancer in postmenopausal women.

Leu Leu leucine.

leucine (Leu, L) leucine an essential amino acid necessary for optimal growth in infants and for nitrogen equilibrium in adults.

leuc(o)- leuc(o)- for words beginning thus, see also those beginning leuko-.

leucovorin leucovorine folinic acid; the calcium salt is used as an antidote for folic acid antagonists, e.g., methotrexate, and in the treatment of megaloblastic anemias due to folic acid deficiency and colorectal carcinoma.

leukapheresis leucaphérèse the selective separation and removal of leukocytes from withdrawn blood, the remainder of the blood then being retransfused into the donor.

leukemia leucémie a progressive, malignant disease of the blood-forming organs, marked by distorted proliferation and development of leukocytes and their precursors in the blood and bone marrow. Adj.: leukemic. acute l. l. aiguë leukemia in which the involved cell line shows little or no differentiation, usually consisting of blast cells; it comprises two types, acute lymphocytic leukemia and acute myelogenous leukemia. acute granulocytic l. l. granulocytaire aiguë acute myelogenous l. acute lymphoblastic l., acute lymphocytic l. (ALL) l. lymphoblastique aiguë one of the two major categories of acute leukemia, characterized by anemia, fatigue, weight loss, easy bruising, thrombocytopenia, granulocytopenia with bacterial infections, bone pain, lymphadenopathy, hepatosplenomegaly, and sometimes spread to the central nervous system. It is subclassified on the basis of the surface antigens expressed, e.g., B-cell type, T-cell type. acute megakaryoblastic l., acute megakaryocytic l. l. aiguë mégacaryoblastique a form of acute myelogenous leukemia in which megakaryocytes are predominant and platelets are increased in the blood. acute monocytic l. l. monocytaire, monoblastique aiguë an uncommon form of acute myelogenous leukemia in which the predominating cells are monocytes. acute myeloblastic l. i. myéloblastique aiguë 1. a common type of acute myelogenous leukemia in which myeloblasts predominate; it is divided into two types on the basis of degree of cell differentiation. 2. acute myelogenous l. acute myelocytic l. l. myélocytaire aiguë acute myelogenous l. acute myelogenous l. (AML) l. myéloïde aiguë one of the two major categories of acute leukemia, with symptoms including anemia, fatigue, weight loss, easy bruising, thrombocytopenia, and granulocytopenia. acute myelomonocytic l. l. myélomonocytaire aiguë a common type of acute myelogenous leukemia, with both malignant monocytes and monoblasts. acute promyelocytic l. l. promyélocytaire aiguë acute myelogenous leukemia in which more than half the cells are malignant promyelocytes. acute undifferentiated l. (AVL) l. aiguë indifférenciée acute myelogenous leukemia in which the predominating cell is so immature it cannot be classified. adult T-cell l., lymphoma (ATL) l. à lymphocytes T de l’adulte, lymphome T an adult-onset, subacute or chronic malignancy of mature T lymphocytes, believed to be caused by human lymphotropic virus type I. aleukemic l. l. aleucémique, leucose aleucémique a form in which the total white blood cell count in the peripheral blood is not elevated; it may be lymphocytic, monocytic, or myelogenous. basophilic l. l. à basophiles leukemia in which the basophilic leukocytes predominate. chronic l. l. chronique leukemia in which the involved cell line is well differentiated, usually B lymphocytes, but immunologically incompetent. chronic granulocytic l. l. granulocytaire chronique chronic leukemia of the myelogenous type, usually associated with a specific chromosomal abnormality and occurring in adulthood. chronic lymphocytic l. (CLL) l. lymphocytaire chronique chronic leukemia of the lymphoblastic type, characterized by lymphadenopathy, fatigue, renal involvement, and pulmonary leukemic infiltrates. chronic myelocytic l., chronic myelogenous l., chronic myeloid l. l. myéloïde chronique chronic granulocytic l. chronic myelomonocytic l. l. myélomonocytaire chronique a chronic, slowly progressing form characterized by malignant monocytes and myeloblasts, splenomegaly, and thrombocytopenia. l. cutis l. cutanée a cutaneous manifestation of leukemia resulting from infiltration of the skin by malignant leukocytes. eosinophilic l. l. à éosinophiles a form in which eosinophils are the predominating cells. granulocytic l. l. granulocytaire myelogenous l. hairy cell l. l. à tricholeucocytes, réticuloendothéliose leucémique chronic leukemia marked by splenomegaly and an abundance of large, mononuclear abnormal cells with numerous irregular cytoplasmic projections that give them a flagellated or hairy appearance in the bone marrow, spleen, liver, and peripheral blood. lymphatic l., lymphoblastic l., lymphocytic l. l. lymphatique a form associated with hyperplasia and overactivity of the lymphoid tissue, with increased levels of circulating malignant lymphocytes or lymphoblasts. lymphogenous l., lymphoid l. l. lymphoïde chronique lymphatic l. lymphosarcoma cell l. l. lymphoblastique B (B-cell type) acute lymphoblastic l. mast cell l. l. à mastocytes a rare form marked by overwhelming numbers of tissue mast cells in the peripheral blood. megakaryoblastic l. l. mégacaryoblastique acute megakaryocytic l. megakaryocytic l. I. mégacaryocytaire 1. acute megakaryocytic l. 2. hemorrhagic thrombocythemia. micromyeloblastic l. l. à micromyéloblastes a form of myelogenous leukemia in which the immature nucleoli-containing cells are small and similar to lymphocytes. monocytic l. l. monocytaire acute monocytic. l. myeloblastic l. I. myéloblastique 1. myelogenous l. 2. acute myeloblastic l. myelocytic l., myelogenous l., myeloid granulocytic l. l. myélocytaire a form arising from myeloid tissue in which the granular polymorphonuclear leukocytes and their precursors predominate. See also acute myelogenous l. and chronic granulocytic l. myelomonocytic l. l. myélomonocytaire acute myelomonocytic l. plasma cell l. l. à plasmocytes a form in which the predominating cell in the peripheral blood is the plasma cell. promyelocytic l. l. promyélocytaire acute promyelocytic l. stem cell l. l. à cellules souches acute undifferentiated l.

leukemid leucémide any of the polymorphic skin eruptions associated with leukemia; clinically, they may be nonspecific, i.e., papular, macular, purpuric, etc., but histopathologically they may represent true leukemic infiltrations.

leukemogen leucémogène any substance which produces leukemia. Adj.: leukemogenic.

leukemoid leucémoïde exhibiting blood and sometimes clinical findings resembling those of leukemia, but due to some other cause.

leukin leukine, leucine a bactericidal substance from leukocyte extract.

leuk(o)- leuc(o)- word element [Gr.], white; leukocyte.

leukoagglutinin leucoagglutinine an agglutinin which acts upon leukocytes.

leukoblastosis leucoblastose abnormal proliferation of leukocytes, as seen in leukemia.

leukocidin leucocidine a substance produced by some pathogenic bacteria that is toxic to polymorphonuclear leukocytes (neutrophils).

leukocyte leucocyte white cell, white blood cell; a colorless blood corpuscle capable of ameboid movement, whose chief function is to protect the body against microorganisms causing disease and which may be classified in two main groups: granular and nongranular. Adj.: leukocytic. agranular l. agranulocyte nongranular l. basophilic l. l. basophile basophil (2). eosinophilic l. l. éosinophile eosinophil. granular l. l. granuleux granulocyte; a leukocyte containing abundant granules in the cytoplasm, such as a neutrophil, eosinophil, or basophil. neutrophilic l. l. neutrophile neutrophil (1). nongranular l. l. non granuleux a leukocyte without specific granules in the cytoplasm, such as a lymphocyte or monocyte.

leukocytogenesis leucocytogenèse leukopoiesis.

leukocytolysis leucocytolyse leukolysis. Adj.: leukocytolytic.

leukocytoma leukocytome a tumor-like mass of leukocytes.

leukocytopenia leucocytopénie leukopenia.

leukocytoplania leucopédèse wandering of leukocytes; passage of leukocytes through a membrane.

leukocytopoiesis leucocytopoïèse leukopoiesis.

leukocytosis leucocytose a transient increase in the number of leukocytes in the blood, due to various causes. basophilic l. l. basophile basophilia (1). eosinophilic l. l. éosinophile eosinophilia. mononuclear l. syndrome mononucléosique mononucleosis. neutrophilic l. l. neutrophile neutrophilia. pathologic l. l. pathologique that due to some morbid condition, such as infection or trauma. physiologic l. l. physiologique that due to a nonpathologic condition such as strenuous exercise.

leukocytospermia leucocytospermie excessive leukocytes in the seminal fluid.

leukocytotaxis cytotaxie de leucocytes leukotaxis.

leukocytotoxicity leucocytotoxicité lymphocytotoxicity.

leukoderma leucodermie an acquired condition with localized loss of pigmentation of the skin. syphilitic l. l. syphilitique indistinct coarsely mottled hypopigmentation, usually on the sides of the neck, in late secondary syphilis.

leukodystrophy leucodystrophie disturbance of the white substance of the brain; see also leukoencephalopathy. globoid cell l. l. à cellules globoïdes Krabbe disease. hereditary adult-onset l. l. dominante de l’adulte an inherited leukoencephalopathy characterized by progressive degeneration of the white matter, with motor disturbances, bowel and bladder incontinence, and orthostatic hypotension. metachromatic l. maladie de Scholz-Greenfield, l. métachromatique an inherited disorder due to accumulation of sulfatide in tissues with a diffuse loss of myelin in the central nervous system; it occurs in several forms, with increasing age of onset correlated to decreasing severity, all initially presenting as mental regression and motor disturbances.

leukoedema leuco-œdème a variant condition of the buccal mucosa, consisting of an increase in thickness of the epithelium and intracellular edema of the stratum spinosum or stratum germinativum.

leukoencephalitis leuco-encéphalite inflammation of the white substance of the brain.

leukoencephalopathy leuco-encéphalopathie any of a group of diseases affecting the white substance of the brain. The term leukodystrophy is used to denote such disorders due to defective formation and maintenance of myelin in infants and children. progressive multifocal l. leucoencéphalite multifocale progressive a form due to opportunistic infection of the central nervous system by the JC virus, with demyelination occurring usually in the cerebral hemispheres and rarely in the brain stem and cerebellum.

leukoerythroblastosis leuco-érythroblastose anemia associated with space-occupying lesions of the bone marrow that cause bone marrow suppression with a variable number of immature cells of the erythrocytic and granulocytic series in the circulation.

leukokeratosis leucokératose leukoplakia.

leukokoria leucocorie any condition marked by the appearance of a whitish reflex or mass in the pupillary area behind the lens.

leukokraurosis maladie de Breisky kraurosis vulvae.

leukolysis leucolyse destruction or disintegration of leukocytes. Adj.: leukolytic.

leukoma leucome pl. leukomata [Gr.] 1. a dense, white corneal opacity. 2. leukoplakia of the buccal mucosa. Adj.: leukomatous. adherent l. l. adhérent a white tumor of the cornea enclosing a prolapsed adherent iris.

leukomyelitis leucomyélite inflammation of the white substance of the spinal cord.

leukonecrosis leuconécrose gangrene with formation of a white slough.

leukonychia leuconychie abnormal whiteness of the nails, either total or in spots or streaks.

leukopathia leucopathie 1. leukoderma. 2. disease of the leukocytes. l. unguium leukopathia unguium leukonychia.

leukopedesis leucopédèse leukocyte emigration.

leukopenia leucopénie reduction of the number of leukocytes in the blood below about 5000 per cubic mm. Adj.: leukopenic. basophilic l. l. basophile basophilopenia. malignant l., pernicious l. l. maligne agranulocytosis.

leukoplakia leucoplasie 1. a white patch on a mucous membrane that will not rub off. 2. oral l. hairy l. l. chevelue a white filiform to flat patch on the tongue or the buccal mucosa, caused by infection with Epstein-Barr virus and associated with human immunodeficiency virus (HIV) infection. oral l. l. orale white, thick patches on the oral mucosa due to hyperkeratosis of the epithelium, producing favorable conditions for development of epidermoid carcinoma; often occurring on the cheeks (l. buccalis), gums, or tongue (l. lingualis). oral hairy l. l. orale chevelue hairy l.

leukopoiesis leucopoïèse production of leukocytes.

leukorrhea leucorrhée a whitish, viscid discharge from the vagina and uterine cavity.

leukosis leucose pl. leukoses proliferation of leukocyte-forming tissue.

leukotaxis leucotaxie cytotaxis of leukocytes; the tendency of leukocytes to collect in regions of injury and inflammation. Adj.: leukotactic.

leukotome leucotome a neurosurgical tool in which a wire loop on one end of a rigid shaft is used to cut tissue.

leukotomy leucotomie prefrontal lobotomy.

leukotoxin leucotoxine a cytoxin destructive to leukocytes.

leukotrichia leucotrichie whiteness of the hair in a circumscribed area.

leukotriene leucotriène any of a group of biologically active compounds derived from arachidonic acid that function as regulators of allergic and inflammatory reactions. They are identified by the letters A, B, C, D, and E, with subscript numerals indicating the number of double bonds in each molecule.

leuprolide leuprolide a synthetic analogue of gonadotropin-releasing hormone, used in the form of the acetate ester as an antiendometriotic agent, antineoplastic, and gonadotropin inhibitor.

levalbuterol lévalbutérol R-albuterol; a β-adrenergic agent used as the hydrochloride salt as a bronchodilator for the treatment and prophylaxis of reversible bronchospasm.

levamisole lévamisole an immunomodulator used with fluorouracil in the treatment of colon cancer, administered as the hydrochloride salt.

levarterenol lévartérénol the levorotatory isomer of norepinephrine, a much more potent pressor agent than the natural dextrorotatory isomer.

levator élévateur pl. levatores 1. a muscle that elevates an organ or structure. 2. an instrument for raising depressed osseous fragments in fractures.

level niveau relative position, rank, or concentration. confidence l. n. de confiance the probability that a confidence interval does not contain the population parameter. l. of significance n. de signification the probability of incorrectly rejecting the null hypothesis.

levetiracetam lévétiracétam an anticonvulsant used in the treatment of partial seizures in adults with epilepsy.

levigation lévigation the grinding to a powder of a moist or hard substance.

lev(o)- lévo- word element [L.], left.

levobetaxolol lévobétaxolol a cardioselective β-adrenergic blocking agent, used topically in the form of the hydrochloride salt in the treatment of glaucoma and ocular hypertension.

levobunolol lévobunolol a nonspecific betaadrenergic blocking agent used as the hydrochloride salt in the treatment of glaucoma and ocular hypertension.

levobupivacaine lévobupivacaïne the S enantiomer of bupivacaine; a local anesthetic used as the hydrochloride salt for local infiltration anesthesia, peripheral nerve block, and epidural anesthesia.

levocabastine lévocabastine an antihistamine applied topically to the conjunctiva as the hydrochloride salt to treat seasonal allergic conjunctivitis.

levocardia lévocardie a term denoting normal position of the heart associated with transposition of other viscera (situs inversus).

levocarnitine lévocarnitine a preparation of the biologically active l-isomer of carnitine used in the treatment of carnitine deficiency.

levoclination lévotorsion rotation of the upper poles of the vertical meridians of the two eyes to the left.

levodopa lévodopa l-dopa; the levorotatory isomer of dopa, used as an antiparkinsonian agent.

levofloxacin lévofloxacine a broad-spectrum antibacterial agent for systemic and ophthalmic use.

levonorgestrel lévonorgestrel the levorotatory form of norgestrel; used as an oral or subdermal contraceptive.

levorotatory lévogyre turning the plane of polarization of polarized light to the left (counterclockwise).

levorphanol lévorphanol an opioid analgesic with properties and actions similar to those of morphine; used as the bitartrate salt as an analgesic and an anesthesia adjunct.

levothyroxine lévothyroxine l-thyroxine, obtained from the thyroid gland of domesticated food animals or prepared synthetically; used as the sodium salt in the treatment of hypothyroidism and the treatment and prophylaxis of goiter and thyroid carcinoma.

levotorsion lévotorsion levoclination.

levoversion lévoversion a turning toward the left.

LFA NIGA left frontoanterior (position of the fetus).

LFP NIGP left frontoposterior (position of the fetus).

LFT NIGT left frontotransverse (position of the fetus).

LH LH luteinizing hormone.

LH-RH LH-RH luteinizing hormone-releasing hormone.

Li Li lithium.

libido libido pl. libidines [L.] 1. sexual desire. 2. the psychic energy derived from instinctive biological drives; in early freudian theory it was restricted to the sexual drive, then expanded to all expressions of love and pleasure, but has evolved to include also the death instinct. Adj.: libidinal.

lice poux plural of louse.

licentiate patenté one holding a license from an authorized agency giving the right to practice a particular profession.

lichen lichen 1. any of certain plants formed by the mutualistic combination of an alga and a fungus. 2. any of various papular skin diseases in which the lesions are typically small, firm papules set close together. l. amyloidosus l. amyloïde see under amyloidosis. l. myxedematosus l. myxœdémateux a condition resembling myxedema but unassociated with hypothyroidism, marked by a fibrocystic proliferation, increased deposition of acid mucopolysaccharides in the skin, and the presence of a circulating paraprotein; it may present as lichenoid papules or urticaria-like plaques and nodules. l. nitidus l. nitidus a chronic inflammatory eruption consisting of many, pinheadsized pale, flat, sharply marginated, glistening, discrete papules, scarcely raised above the skin level. l. planopilaris l. planopilaris a variant of lichen planus characterized by pointed, horny papules around hair follicles, as well as typical lesions of lichen planus. l. planus, l. ruber planus l. plan an inflammatory skin disease with wide, flat, violaceous, shiny papules in circumscribed patches; it may also involve hair follicles, nails, or buccal mucosa. l. sclerosus sclérolichen a chronic atrophic skin disease marked by white papules with erythematous halos and keratotic plugging, usually around the external genitalia or in the perianal region. l. scrofulosorum, l. scrofulosus l. scrophulosorum an eruption of minute reddish lichenoid follicular papules seen in children and young adults with tuberculosis. l. simplex chronicus l. simplex chronique, névrodermite circonscrite a dermatosis caused by excessive scratching or rubbing of itches, marked by discrete or confluent papular eruptions, usually in a localized area. l. spinulosus l. spinulosus a condition in which there is a horn or spine in the center of each hair follicle. l. striatus l. striatus a self-limited condition characterized by a linear lichenoid eruption, usually in children.

lichenification lichénification thickening and hardening of the skin, with exaggeration of its normal markings.

licorice réglisse glycyrrhiza; the dried rhizome, roots, and stolons of various species of the perennial herb Glycyrrhiza, used as an expectorant and for the treatment of gastritis; also used in traditional Chinese medicine, ayurveda, and folk medicine.

lidocaine lidocaïne an anesthetic with sedative, analgesic, and cardiac depressant properties, applied topically in the form of the base or hydrochloride salt as a local anesthetic; also used in the latter form as a cardiac antiarrhythmic and to produce infiltration anesthesia and various nerve blocks.

lie orientation the relation of the long axis of the fetus with respect to that of the mother; cf. presentation and position. oblique l. position oblique the situation during labor when the long axis of the fetal body crosses the long axis of the maternal body at an angle close to 45 degrees. transverse l. position transverse the situation during labor when the long axis of the fetus crosses the long axis of the mother; see table under position.

lien lien [L.] spleen. Adj.: lienal. l. accessorius l. accessorius, rate accessoire accessory spleen. l. mobilis l. mobilis, rate accessoire floating spleen.

lien(o)- lién(o)- word element [L.], spleen; see also words beginning splen(o)-.

lientery lientérie diarrhea with passage of undigested food. Adj.: lienteric.

LIF LIF left iliac fossa; leukocyte inhibitory factor.

life vie the aggregate of vital phenomena; the quality or principle by which living things are distinguished from inorganic matter, as manifested by such phenomena as metabolism, growth, reproduction, adaptation, etc.

ligament ligament 1. a band of fibrous tissue connecting bones or cartilages, serving to support and strengthen joints. 2. a double layer of peritoneum extending from one visceral organ to another. 3. cordlike remnants of fetal tubular structures that are nonfunctional after birth. Adj.: ligamentous. accessory l. l. accessoire one that strengthens or supports another. alar l’s l. alaires 1. two bands passing from the apex of the dens to the medial side of each occipital condyle. 2. a pair of folds of the synovial membrane of the knee joint. annular stapedial l. l. annulaire de l’étrier a ring of fibrous tissue that attaches the base of the stapes to the fenestra vestibuli of the inner ear. anococcygeal l. l. anococcygien a fibrous band connecting the posterior fibers of the sphincter of the anus to the coccyx. arcuate l’s l. arqués 1. the arched ligaments connecting the diaphragm with the lowest ribs and the first lumbar vertebra. 2. ligamenta flava. Brard l. l. de Bérard the suspensory ligament of the pericardium. Bertin l., Bigelow l. l. de Bertin iliofemoral l. l. of Botallo l. artériel a strong thick fibromuscular cord extending from the pulmonary artery to the aortic arch; it is the remains of the ductus arteriosus. Bourgery l. l. de Bourgery oblique popliteal ligament; a broad band of fibers extending from the medial condyle of the tibia across the back of the knee joint to the lateral epicondyle of the femur. broad l. l. large 1. a broad fold of peritoneum supporting the uterus, extending from the uterus to the wall of the pelvis on either side. 2. a sickle-shaped sagittal fold of perineum helping attach the liver to the diaphragm and separating the left and right hepatic lobes. Brodie l. l. huméral transverse de Gordon transverse humeral l. Burns l. l. de Burns falciform process (1). Campbell l. l. de Campbell suspensory l. (2). cardinal l. l. cardinal part of a thickening of the visceral pelvic fascia beside the cervix and vagina, passing laterally to merge with the upper fascia of the pelvic diaphragm. carpal l., transverse l. carpien transverse flexor retinaculum of hand. Colles l. l. de Colles a triangular band of fibers arising from the lacunar ligament and pubic bone and passing to the linea alba. conoid l. l. conoïde the posteromedial portion of the coracoclavicular ligament, extending from the coracoid process to the inferior surface of the clavicle. conus l. l. de Krehl, tendo infundibuli a collagenous band connecting the posterior surface of the pulmonary annulus and the muscular infundibulum to the root of the aorta. Cooper l. l. de Cooper pectineal l. coracoclavicular l. l. coracoclaviculaire a band joining the coracoid process of the scapula and the acromial extremity of the clavicle, consisting of two ligaments, the conoid and trapezoid. cotyloid l. l. cotyloïdien a ring of fibrocartilage connected with the rim of the acetabulum. cruciate l’s of knee l. croisés more or less cross-shaped ligaments, one anterior and one posterior, arising from the femur and passing through the intercondylar space to attach to the tibia. cystoduodenal l. l. cystico-duodénal an anomalous fold of peritoneum extending between the gallbladder and the duodenum. diaphragmatic l. l. diaphragmatique the involuting urogenital ridge that becomes the suspensory ligament of the ovary. falciform l. l. falciforme du foie a sickle-shaped sagittal fold of peritoneum that helps attach the liver to the diaphragm. flaval l’s l. jaunes ligamenta flava. glenohumeral l’s l. gléno-huméraux bands, usually three, on the inner surface of the articular capsule of the humerus, extending from the glenoid lip to the anatomical neck of the humerus. glenoid l. bourrelet glénoïdien 1. (in the pl.) dense bands on the plantar surfaces of the metatarsophalangeal joints. 2. see under lip. Henle l. l. de Henle falx inguinalis. Hey l. l. de Burns falciform process (1). iliofemoral l. l. iliofémoral a very strong triangular or inverted Y-shaped band covering the anterior and superior portions of the hip joint. iliotrochanteric l. l. ilio-trochantérien a portion of the articular capsule of the hip joint. inguinal l. l. inguinal a fibrous band running from the anterior superior spine of the ilium to the spine of the pubis. lacunar l. l. lacunaire a membrane with its base just medial to the femoral ring, one side attached to the inguinal ligament and the other to the pectineal line of the pubis. Lisfranc l. l. de Lisfranc, interosseux interne a fibrous band extending from the medial cuneiform bone to the second metatarsal. Lockwood l. l. de Lockwood a suspensory sheath supporting the eyeball. medial l. l. médial 1. a large fan-shaped ligament on the medial side of the ankle. 2. the medial ligament of temporomandibular articulation. meniscofemoral l’s l. méniscofémoraux two small fibrous bands of the knee joint attached to the lateral meniscus, one (the anterior) extending to the anterior cruciate ligament and the other (the posterior) to the medial femoral condyle. nephrocolic l. l. néphrocolique fasciculi from the fatty capsule of the kidney passing down on the right side to the posterior wall of the ascending colon and on the left side to the posterior wall of the descending colon. nuchal l. l. nuchal a broad, fibrous, roughly triangular sagittal septum in the back of the neck, separating the right and left sides. ovarian l. l. de l’ovaire a musculofibrous cord in the broad ligament, joining the ovary to the upper part of the lateral margin of the uterus just below the attachment of the uterine tube. patellar l. l. rotulien the continuation of the central portion of the tendon of the quadriceps femoris muscle distal to the patella, extending from the patella to the tuberosity of the tibia. pectineal l. l. pectinéal a strong aponeurotic lateral continuation of the lacunar ligament along the pectineal line of the pubis. periodontal l. l. alvéolodentaire the fibrous connective tissue that surrounds the root of a tooth, separating it from and attaching it to the alveolar bone, and serving to hold the tooth in its socket. It extends from the base of the gingival mucosa to the fundus of the bony socket. phrenicocolic l. l. phrénico-colique a peritoneal fold passing from the left colic flexure to the adjacent part of the diaphragm. Poupart l. l. de Poupart inguinal l. pulmonary l. l. pulmonaire a vertical fold extending from the hilus to the base of the lung. rhomboid l. of clavicle l. rhomboïde de la clavicule a ligament connecting cartilage of the first rib to the undersurface of the clavicle. Robert l. l. croisé de Robert posterior meniscofemoral l. round l. l. rond 1. (of femur) a broad ligament arising from the fatty cushion of the acetabulum and inserted on the head of the femur. 2. (of uterus) a fibromuscular band attached to the uterus near the uterine tube, passing through the inguinal ring to the labium majus. Schlemm l’s l. de Schlemm two ligamentous bands of the capsule of the shoulder joint. subflaval l’s l. jaunes ligamenta flava. suspensory l. l. suspenseur 1. (of lens) ciliary zonule. 2. (of axilla) a layer ascending from the axillary fascia and ensheathing the pectoralis minor muscle. 3. (of ovary) the portion of the broad ligament lateral to and above the ovary. 4. (of breast) one of numerous fibrous processes extending from the body of the mammary gland to the dermis. 5. (of clitoris) a strong fibrous band attaching the root of the clitoris to the linea alba and pubic symphysis. 6. (of penis) a strong fibrous band that attaches the root of the penis to the linea alba and pubic symphysis. synovial l. l. synovial a large synovial fold. tendinotrochanteric l. l. tendinotrochantérien a portion of the capsule of the hip joint. tracheal l’s l. annulaires circular horizontal ligaments that join the tracheal cartilages together. transverse l. l. transverse short fibers that connect the posterior surface of the neck of a rib with the anterior surface of the transverse process of the corresponding vertebra. transverse humeral l. l. huméral transverse a band of fibers bridging the intertubercular groove of the humerus and holding the tendon in the groove. trapezoid l. l. trapézoïde the anterolateral portion of the coracoclavicular ligament, extending from the upper surface of the coracoid process to the trapezoid line of the clavicle. umbilical l., median l. ombilical médian a fibrous cord, the remains of the obliterated umbilical artery, running cranialward beside the bladder to the umbilicus. uteropelvic l’s l. utéropelviens expansions of muscular tissue in the broad ligament, radiating from the fascia over the internal obturator to the side of the uterus and the vagina. ventricular l. l. ventriculaire vestibular l. vesicoumbilical l. l. vésico-ombilical median umbilical l. vesicouterine l. l. vésicoutérin a ligament that extends from the anterior aspect of the uterus to the bladder. vestibular l. l. vestibulaire the membrane extending from the thyroid cartilage in front to the anterolateral surface of the arytenoid cartilage behind. vocal l. l. vocal the elastic tissue membrane extending from the thyroid cartilage in front to the vocal process of the arytenoid cartilage behind. Weitbrecht l. l. de Weitbrecht a small ligamentous band extending from the ulnar tuberosity to the radius. Wrisberg l. l. de Wrisberg posterior meniscofemoral l. Y l. l. en Y iliofemoral l. yellow l’s l. jaunes ligamenta flava.

ligamentopexy ligamentopexie fixation of the uterus by shortening or suturing the round ligament.

ligamentum ligamentum pl. ligamenta [L.] ligament. ligamenta flava ligamenta flava yellow ligaments: a series of bands of yellow elastic tissue attached to and extending between the ventral portions of the laminae of two adjacent vertebrae, from the axis to the sacrum. They assist in maintaining or regaining the erect position and serve to close in the spaces between the arches.

ligand ligand an organic molecule that donates the necessary electrons to form coordinate covalent bonds with metallic ions. Also, an ion or molecule that reacts to form a complex with another molecule.

ligase ligase any of a class of enzymes that catalyze the joining together of two molecules coupled with the breakdown of a pyrophosphate bond in ATP or a similar triphosphate.

ligation ligature 1. the application of a ligature. 2. the process of annealing or joining. tubal l. l. des trompes tubaire sterilization of the female by constricting, severing, or crushing the uterine tubes.

ligature ligature any material, such as thread or wire, used for tying a vessel or to constrict a part.

light lumière electromagnetic radiation with a range of wavelength between 3900 (violet) and 7700 (red) angstroms, capable of stimulating the subjective sensation of sight; sometimes considered to include ultraviolet and infrared radiation as well. idioretinal l. l. propre de l’œil the sensation of light in the complete absence of external stimuli. intrinsic l. l. propre de l’œil the dim light always present in the visual field. polarized l. l. polarisée light of which the vibrations are made over one plane or in circles or ellipses. ultraviolet l. rayonnement ultraviolet see under ray. Wood l. l. de Wood ultraviolet radiation from a mercury vapor source, transmitted through a filter that holds back all but a few violet rays and passes ultraviolet wavelengths of about 365 nm.

lightening allégement the sensation of decreased abdominal distention produced by the descent of the uterus into the pelvic cavity, two to three weeks before labor begins.

lignoceric acid acide lignocérique a saturated 24-carbon fatty acid occurring in sphingomyelin and as a minor constituent of many plant fats.

limb 1. membre member or extremity; one of the paired appendages of the body used in locomotion or grasping; in humans, an arm or leg with all its parts. 2. membre, branche, ligne a structure or part resembling an arm or leg. anacrotic l. partie anacrote ascending l. (2). ascending l. 1. bec-de-perroquet the distal part of the loop of Henle. 2. partie ascendante du tracé sphygmographique anacrotic l.; the ascending portion of an arterial pulse tracing. catacrotic l. p. catacrote descending l. (2). descending l. 1. bec-de-perroquet the proximal part of the loop of Henle. 2. partie descendante du tracé sphygmographique catacrotic l.; the descending portion of an arterial pulse tracing. lower l. m. inférieur the limb of the body extending from the gluteal region to the foot; it is specialized for weight-bearing and locomotion. See also leg. pectoral l. m. pectoral thoracic l. pelvic l. m. pelvien 1. the leg, or a homologous part. 2. the limb attached to the pelvic girdle; the lower limb of a human or a homologous structure such as a hind limb on another animal. phantom l. m. fantôme the sensation, after amputation of a limb, that the absent part is still present; there may also be paresthesias, transient aches, and intermittent or continuous pain perceived as originating in the absent limb. thoracic l. m. thoracique the limb attached to the thoracic girdle; the upper limb of a human or a homologous structure (wing, foreleg, etc.) in another animal. upper l. m. supérieur the limb of the body extending from the superior part of the deltoid region to the hand; it is specialized for functions requiring great mobility. See also arm.

limbic limbique pertaining to a limbus, or margin; see also under system.

limbus limbe pl. limbi [L.] an edge, fringe, or border. corneal l. l. cornéen the edge of the cornea where it joins the sclera. spiral l. l. spiral the thickened periosteum of the osseous spiral lamina of the cochlea.

lime 1. chaux calcium oxide, a corrosively alkaline and caustic earth, CaO; having various industrial uses and also a pharmaceutic necessity. 2. limon the acid fruit of the tropical tree, Citrus aurantifolia; its juice contains ascorbic acid. soda l. c. sodée see under soda.

limen limen pl. limina [L.] a threshold or boundary. l. of insula, l. insulae l. de l’insula the point at which the cortex of the insula is continuous with the cortex of the frontal lobe. l. nasi l. nasi the ridge marking the boundary between the vestibule of the nose and the nasal cavity proper.

liminal liminaire barely perceptible; pertaining to a threshold.

liminometer réflexomètre an instrument for measuring the strength of a stimulus that just induces a tendon reflex.

limitans limitans [L.] limiting.

limit dextrinase dextrinase limite α-dextrinase.

limp boiterie any gait that avoids weight bearing by one leg.

lincomycin lincomycine an antibiotic, primarily a gram-positive specific antibacterial, produced by a variant of Streptomyces lincolnensis; used as the hydrochloride salt.

lindane lindane the gamma isomer of benzene hexachloride, used as a topical pediculicide and scabicide.

line ligne 1. a stripe, streak, or narrow ridge. 2. an imaginary line connecting different anatomic landmarks. Adj.: linear. absorption l’s raies d’absorption dark lines in the spectrum due to absorption of light by the substance through which the light has passed. anocutaneous l. l. anocutanée pectinate l. Beau l’s l. de Beau transverse furrows on the fingernails, usually a sign of a systemic disease but also due to other causes. bismuth l. liséré bismuthique a thin blue-black line along the gingival margin in bismuth poisoning. blood l. lignée sanguine a line of direct descent through several generations. cement l. l. cémentante a line visible in microscopic examination of bone in cross section, marking the boundary of an osteon (haversian system). cervical l. l. cervicale anatomical designation for the cementoenamel junction, the dividing line between the crown and root portions of a tooth. cleavage l’s l. de Langer linear clefts in the skin indicative of direction of the fibers. costoclavicular l. linea parasternalis parasternal l. l. of Douglas l. de Douglas a crescentic line marking the termination of the posterior layer of the sheath of the rectus abdominis muscle. epiphyseal l. l. épiphysaire 1. a plane or plate on a long bone, visible as a line, marking the junction of the epiphysis and diaphysis. 2. a strip of lesser density on the radiograph of a long bone, representing that plane or plate. l’s of expression l. d’expression the natural skin lines and creases of the face and neck; the preferred lines of incision in facial and cervical surgery. gingival l. l. gingivale 1. a line determined by the level to which the gingiva extends on a tooth. 2. any linear mark visible on the surface of the gingiva. gluteal l. l. glutéale any of the three rough curved lines (anterior, inferior, and posterior) on the gluteal surface of the ala of the ilium. Harris l’s l. de Harris lines of retarded growth seen radiographically at the epiphyses of long bones. hot l. service d’assistance téléphonique see under H. iliopectineal l. l. innominée iliopectinée a ridge on the ilium and pubes showing the brim of the true pelvis. intertrochanteric l. l. intertrochantérienne a line running obliquely from the greater to the lesser trochanter on the anterior surface of the femur. lead l. liseré de Burton, liseré saturnin a gray or bluish black line at the gingival margin in lead poisoning. mammary l. l. mammaire see under ridge. mammillary l. l. mamillaire an imaginary vertical line passing through the center of the nipple. median l. l. médiane an imaginary line dividing the body surface equally into right and left sides. milk l. l. lactéale mammary ridge. mylohyoid l. l. mylo-hyoïdienne a ridge on the inner surface of the lower jaw from the base of the symphysis to the ascending rami behind the last molar tooth. nasobasilar l. l. nasiobasilaire one through the basion and nasion. Nélaton l. l. de Nélaton one from the anterior superior spine of the ilium to the most prominent part of the tuberosity of the ischium. nuchal l’s l. nuchales three lines (inferior, superior, highest) on the outer surface of the occipital bone; see also external occipital crest. parasternal l. l. parasternale an imaginary line midway between the mammillary line and the border of the sternum. pectinate l. l. pectinée one marking the junction of the zone of the anal canal lined with stratified squamous epithelium and the zone lined with columnar epithelium. pectineal l. 1. crête pectinéale a line running down the posterior surface of the shaft of the femur, giving attachment to the pectineus muscle. 2. the anterior border of the superior ramus of the pubis. semilunar l. l. semi-lunaire de Spieghel a curved line along the lateral border of each rectus abdominis muscle, marking the meeting of the aponeuroses of the internal oblique and transverse abdominal muscles. Shenton l. l. de Shenton de Ménard a curved line seen in radiographs of the normal hip, formed by the top of the obturator foramen. sternal l. l. sternale an imaginary vertical line on the anterior body surface, corresponding to the lateral border of the sternum. subcostal l. l. sous-costale a transverse line on the surface of the abdomen at the level of the lower edge of the tenth costal cartilage. Sydney l. pli de Sidney a palmar crease correlated with an increased risk for leukemia and other malignancies in childhood. temporal l. l. temporale 1. either of the curved ridges, inferior and superior, on the outside of the parietal bone, continuous with the temporal line of the frontal bone, 2. a ridge extending superiorly and posteriorly from the zygomatic process of the frontal bone. terminal l. of pelvis l. terminale du bassin one on the inner surface of each pelvic bone, from the sacroiliac joint to the iliopubic eminence anteriorly, separating the false from the true pelvis. trapezoid l. l. trapézoïde a ridge on the inferior surface of the clavicle for attachment of the trapezoid ligament. Voigt l. l. de Voigt a dorsoventral pigmented line of demarcation on the skin along the lateral edge of the biceps muscle; seen in 20 to 26 per cent of blacks and rarely in whites.

linea linea pl. lineae [L.] line; in anatomy, a narrow ridge or streak on the surface of a structure. l. alba l. alba white line; the tendinous median line on the anterior abdominal wall between the two rectus muscles. l. aspera l. aspera, ligne âpre a rough longitudinal line on the back of the femur for muscle attachments. l. epiphysialis l. epiphysialis epiphyseal line. l. glutea l. glutea gluteal line. l. nigra l. nigra, ligne noire the linea alba when it has become pigmented in pregnancy. l. splendens l. splendens the sheath for the anterior spinal artery formed by the pia mater in the anterior median fissure of the spinal cord.

lineage lignage, lignée descent traced down from or back to a common ancestor. cell l. l. cellulaire the developmental history of cells as traced from the first division of the original cell or cells.

liner fond protecteur material applied to the inside of the walls of a cavity or container for protection or insulation of the surface.

linezolid linézolide a synthetic oxazolidinoneantibacterial, effective against gram-positive organisms.

lingua lingua pl. linguae [L.] tongue. Adj.: lingual. l. geographica l. géographique benign migratory glossitis. l. nigra l. nigra, langue noire black hairy tongue. l. plicata l. plicata fissured tongue.

lingual lingual 1. pertaining to or near the tongue. 2. in dental anatomy, facing the tongue or oral cavity.

Linguatula Linguatula a genus of wormlike arthropods, the adults of which inhabit the respiratory tract of vertebrates; the larvae are found in the lungs and other internal organs. It includes L. serrata (L. rhinaria), which parasitizes dogs and cats and sometimes humans.

lingula lingula pl. lingulae [L.] a small, tonguelike structure, such as the projection from the lower portion of the upper lobe of the left lung (l. pulmonis sinistri), or the bony ridge between the body and great wing of the sphenoid (l. sphenoidalis). Adj.: lingular.

lingulectomy lingulectomie excision of the lingula of the left lung.

lingu(o)- lingu(o)- word element [L.], tongue.

linguopapillitis papillite linguale inflammation or ulceration of the papillae of the edges of the tongue.

linguoversion linguoversion displacement of a tooth lingually from the line of occlusion.

liniment liniment an oily liquid preparation to be used on the skin.

linitis linite inflammation of gastric cellular tissue. l. plastica l. plastique diffuse fibrous proliferation of the submucous connective tissue of the stomach, resulting in thickening and fibrosis so that the organ is constricted, inelastic, and rigid (like a leather bottle).

linkage 1. liaison the connection between different atoms in a chemical compound, or the symbol representing it in structural formulas; see also bond. 2. liaison génétique in genetics, the association of genes having loci on the same chromosome, which results in the tendency of a group of such nonallelic genes to be associated in inheritance. sex l. hérédité liée au sexe the location of a gene responsible for a specific trait on a sex chromosome, resulting in sexually dependent inheritance and expression of the trait.

linoleate linoléate a salt (soap), ester, or anionic form of linoleic acid.

linoleic acid acide linoléique a polyunsaturated fatty acid, occurring as a major constituent of many vegetable oils; it is used in the biosynthesis of prostaglandins and cell membranes.

linolenate linolénate a salt (soap), ester, or anionic form of linolenic acid.

linolenic acid acide linolénique a polyunsaturated 18-carbon essential fatty acid occurring in some fish oils and many seed-derived oils.

linseed graine de lin flaxseed; the dried ripe seed of Linum usitatissimum, the common flax plant, used as a laxative and a topic demulcent and emollient, and a source of α-linolenic acid.

lint charpie an absorbent surgical dressing material.

liothyronine liothyronine a synthetic pharmaceutical preparation of the levorotatory isomer of triiodothyronine, used as the sodium salt in the treatment of hypothyroidism and the treatment and prophylaxis of goiter and thyroid carcinoma.

liotrix liotrix a 1:4 mixture of liothyronine sodium and levothyroxine sodium by weight; used as the sodium salt in the treatment of hypothyroidism and the treatment and prophylaxis of goiter and thyroid carcinoma.

lip lèvre 1. the upper or lower fleshy margin of the mouth. 2. any liplike part; labium. cleft l. bec-de-lièvre a congenital cleft or defect in the upper lip. glenoid l. bourrelet glénoïdien a ring of fibrocartilage joined to the rim of the glenoid cavity. Hapsburg l. l. de Habsburg a thick, overdeveloped lower lip that often accompanies Hapsburg jaw.

lipaciduria lipacidurie fatty acids in the urine.

lipase lipase any enzyme that catalyzes the cleavage of a fatty acid anion from a triglyceride or phospholipid.

lipectomy lipectomie excision of a localized area of subcutaneous adipose tissue. suction l., suction-assisted l. liposuccion liposuction; surgical removal of localized fat deposits via high pressure vacuum, applied by means of a suction curet or cannula inserted subdermally through small incisions.

lipedema lipœdème an accumulation of excess fat and fluid in subcutaneous tissues.

lipemia lipémie hyperlipidemia. Adj.: lipemic. alimentary l. l. alimentaire that occurring after ingestion of food. l. retinalis lipemia retinalis that manifested by a milky appearance of the veins and arteries of the retina.

lipid lipide any of a heterogeneous group of fats and fatlike substances, including fatty acids, neutral fats, waxes, and steroids, which are water-insoluble and soluble in nonpolar solvents. Lipids, which are easily stored in the body, serve as a source of fuel, are an important constituent of cell structure, and serve other biological functions. Compound lipids comprise the glycolipids, lipoproteins, and phospholipids.

lipidemia lipidémie hyperlipidemia.

lipidosis lipidose pl. lipidoses any disorder of lipid metabolism involving abnormal accumulation of lipids in the reticuloendothelial cells.

lipiduria lipidurie adiposuria; lipids in the urine.

lip(o)- lip(o)- word element [Gr.], fat; lipid.

lipoamide lipo-amide the functional form of lipoic acid, linked to the lysine side chain of any of several enzyme complexes that catalyze the oxidative decarboxylation of keto acids.

lipoarthritis lipoarthrite inflammation of fatty tissue of a joint.

lipoatrophy lipoatrophie atrophy of subcutaneous fatty tissues of the body.

lipoblast lipoblaste a connective tissue cell which develops into a fat cell.Adj.: lipoblastic.

lipoblastoma lipoblastome a benign fatty tumor composed of a mixture of embryonic lipoblastic cells in a myxoid stroma and mature fat cells, with the cells arranged in lobules.

lipoblastomatosis lipoblastomatose the occurrence of multiple lipoblastomas locally diffused but without a tendency to metastasize.

lipocardiac lipocardiaque relating to a fatty heart.

lipochondroma lipochondrome chondrolipoma.

lipochrome lipochrome any of a group of fatsoluble hydrocarbon pigments, such as carotene, xanthophyll, lutein, chromophane, and the natural coloring material of butter, egg yolk, and yellow corn.

lipocyte lipocyte 1. fat cell. 2. a fat-storing cell of the liver.

lipodystrophia lipodystrophie lipodystrophy. l. progressiva lipodystrophia progressiva progressive lipodystrophy.

lipodystrophy lipodystrophie any disturbance of fat metabolism. congenital generalized l., congenital progressive l. l. congénitale généralisée total l. generalized l. l. généralisée total l. partial l., progressive l. l. partielle progressive and symmetrical loss of subcutaneous fat from the parts above the pelvis, beginning with facial emaciation and progressing downward, giving an apparent and possibly real accumulation of fat about the thighs and buttocks. total l. l. totale a recessive condition marked by the virtual absence of subcutaneous adipose tissue, macrosomia, visceromegaly, hypertrichosis, acanthosis nigricans, and reduced glucose tolerance in the presence of high insulin levels.

lipofuscin lipofuscine any of a class of fatty pigments formed by the solution of a pigment in fat.

lipofuscinosis lipofuscinose any disorder due to abnormal storage of lipofuscins. neuronal ceroid-l. céroïde-l. neuronale any of several genetic lipidoses characterized by progressive neurodegeneration, loss of vision, and a fatal course; included are Janský-Bielschowsky disease, Vogt-Spielmeyer disease, and Kufs disease.

lipogenesis lipogenèse the formation of fat; the transformation of nonfat food materials into body fat. Adj.: lipogenetic.

lipogenic adipogène forming, producing, or caused by fat.

lipogranuloma lipogranulome a foreign body inflammation of adipose tissue containing granulation tissue and oil cysts.

lipogranulomatosis lipogranulomatose a condition of faulty lipid metabolism in which yellow nodules of lipoid material are deposited in the skin and mucosae, giving rise to granulomatous reactions.

lipohypertrophy lipohypertrophie hypertrophy of subcutaneous fat. insulin l. l. insulinaire localized hypertrophy of subcutaneous fat at insulin injection sites caused by the lipogenic effect of insulin.

lipoic acid acide lipoïque a necessary cofactor for several enzyme complexes involved in the oxidative decarboxylation of keto acids, where it occurs in the form lipoamide. It is used as a dietary supplement for its antioxidant properties.

lipoid lipoïde fatlike.

lipolysis lipolyse the splitting up or decomposition of fat. Adj.: lipolytic.

lipoma lipome a benign, soft, rubbery, encapsulated tumor of adipose tissue, usually composed of mature fat cells.

lipomatosis lipomatose abnormal localized or tumorlike accumulations of fat in the tissues. multiple symmetric l. l. symétrique circonscrite multiple lipomas that surround the neck. renal l. l. rénale fatty masses within the kidney.

lipomeningocele lipoméningocèle meningocele associated with an overlying lipoma.

lipomyelomeningocele lipomyéloméningocèle myelomeningocele with an overlying lipoma.

lipomyoma myolipome myolipoma.

lipomyxoma lipomyxome myxolipoma.

lipopenia lipopénie deficiency of lipids in the body.

lipophage lipophage a cell that absorbs or ingests fat.

lipophagia lipophagie lipolysis. Adj.: lipophagic.

lipophilia lipophilie 1. affinity for fat. 2. solubility in lipids. Adj.: lipophilic.

lipoplasty lipoplastie liposuction.

lipopolysaccharide lipopolysaccharide 1. a molecule in which lipids and polysaccharides are linked. 2. a major component of the cell wall of gram-negative bacteria; lipopolysaccharides are endotoxins and important antigens.

lipoprotein lipoprotéine a complex of lipids and apolipoproteins, the form in which lipids are transported in the blood. α-l., α alpha l. -l. one with electrophoretic mobility equivalent to that of the α₁-globulins, e.g., high-density lipoprotein. β-l., beta l. β-l. one with electrophoretic mobility equivalent to that of the β-globulins, e.g., low-density lipoprotein. floating beta l’s β-l. flottantes β-VLDL. highdensity l., (HDL) l. de haute densité a class of plasma lipoproteins that promote transport of cholesterol from extrahepatic tissue to the liver for excretion in the bile; serum levels have been negatively correlated with premature coronary heart disease. intermediate-density l., (IDL) l. de densité intermédiaire a class of lipoproteins formed in the degradation of very-low-density lipoproteins; some are cleared rapidly into the liver and some are degraded to low-density lipoproteins. low-density l. (LDL) l. de basse densité a class of plasma lipoproteins that transport cholesterol to extrahepatic tissues; high serum levels have been correlated with premature coronary heart disease. Lp(a) l. l. Lp(a) a lipoprotein particle containing apolipoprotein B-100 as well as an antigenically unique apolipoprotein; its occurrence at high levels in plasma has been correlated with increased risk of heart disease. pre-β-l., pre-beta l. pré-β-l. very-low-density lipoprotein sinking pre-β-l. pré-β-l. plongeante Lp(a) l. very-highdensity l. (VHDL) l. de très haute densité a class of lipoproteins composed predominantly of proteins and also containing a high concentration of free fatty acids. very-low-density l. (VLDL) l. de très faible densité a class of lipoproteins that transport triglycerides from the intestine and liver to adipose and muscle tissues; they contain primarily triglycerides with some cholesteryl esters.

lipoprotein lipase lipoprotéine-lipase an enzyme that catalyzes the hydrolytic cleavage of fatty acids from triglycerides (or di- or monoglycerides) in chylomicrons, very-low-density lipoproteins, and low-density lipoproteins.

liposarcoma liposarcome a malignant mesenchymal tumor usually in the upper thigh, having primitive lipoblastic cells with lipoblastic or lipomatous differentiation, sometimes with foci of normal fat cells.

liposis lipose lipomatosis.

liposoluble liposoluble soluble in fats.

liposome liposome a microscopic spherical particle formed by a lipid bilayer enclosing an aqueous compartment.

liposuction liposuccion suction-assisted lipectomy.

lipotrophy lipotrophie increase of bodily fat. Adj.: lipotrophic.

lipotropic lipotrope acting on fat metabolism by hastening removal or decreasing the deposit of fat in the liver; also, an agent having such effects.

lipotropin lipotropine any of several prohormones that promote lipolysis; the most important one in humans is β-lipotropin. β-l. β-l. a prohormone synthesized by cells of the adenohypophysis; it promotes fat mobilization and skin darkening by stimulation of melanocytes and is the precursor of the endorphins.

lipovaccine lipovaccin a vaccine in a vegetable oil vehicle.

lipoxidase lipoxydase lipoxygenase.

lipoxygenase lipoxygénase an enzyme that catalyzes the oxidation of polyunsaturated fatty acids to form a peroxide of the acid.

lipping 1. lippe, image radiologique cunéiforme a wedge-shaped shadow in the radiograph of chondrosarcoma between the cortex and the elevated periosteum. 2. bec-de-perroquet bony overgrowth in osteoarthritis.

liquefacient liquéfacient 1. producing or pertaining to liquefaction. 2. an agent that produces liquefaction.

liquefaction liquéfaction conversion into a liquid form.Adj.: liquefactive.

liquefy liquéfier to become or cause to become liquid.

liquid liquide 1. a substance that flows readily in its natural state. 2. flowing readily; neither solid nor gaseous.

liquor liqueur pl. liquors, liquores [L.] 1. a liquid, especially an aqueous solution containing a medicinal substance. 2. a term applied to certain body fluids. l. amnii liquor amnii amniotic fluid. l. cerebrospinalis liquor cerebrospinalis cerebrospinal fluid. l. folliculi liquor folliculi follicular fluid.

lisinopril lisinoprile an angiotensin-converting enzyme inhibitor used in the treatment of hypertension, congestive heart failure, and acute myocardial infarction.

lissencephaly lissencéphalie agyria. Adj.: lissencephalic.

Listeria Listeria a genus of small, gram-positive, coccoid bacteria of the family Listeriaceae; L. monocytogenes causes listeriosis.

Listeriaceae Listeriaceae a family of grampositive, non-spore-forming bacteria of the order Bacillales.

listeriosis listériose infection caused by Listeria monocytogenes. Infection in utero results in abortion, stillbirth, or prematurity; that during birth causes cardiorespiratory distress, diarrhea, vomiting, and meningitis; and in adults it causes meningitis, endocarditis, and disseminated granulomatous lesions.

listerism listérisme the principles and practice of antiseptic and aseptic surgery.

liter (L) litre a basic unit of volume used for liquids with the SI system, equal to 1000 cubic centimeters, or 1 cubic decimeter, or to 1.0567 quarts liquid measure.

lithiasis lithiase the formation or presence of calculi or other concretions.

lithium (Li) lithium chemical element (see Table of Elements), at. no. 3. Its salts, especially l. carbonate and l. citrate, are used to treat and prevent manic states in bipolar disorder.

lith(o)- lith(o)- word element [Gr.], stone; calculus.

lithoclast lithoclaste lithotrite.

lithogenesis lithogenèse formation of calculi. Adj.: lithogenic, lithogenous.

litholapaxy litholapaxie lithotripsy.

litholysis litholyse dissolution of calculi. Adj.: litholytic.

lithonephritis lithonéphrite inflammation of the kidney due to irritation by calculi.

lithotomy lithotomie 1. incision of a duct or organ for removal of calculi. 2. cystolithotomy.

lithotripsy lithotripsie the crushing of a calculus within the urinary system or gallbladder, followed at once by the washing out of the fragments; it may be performed surgically or by noninvasive methods, such as by laser or by shock waves. extracorporeal shock wave l. l. extracorporelle par ondes de choc a procedure for treating upper urinary tract stones: the patient is immersed in a large tub of water and a high-energy shock wave generated by a high-voltage spark is focused on the stone by an ellipsoid reflector. The stone disintegrates into particles, which are passed in the urine. pneumatic l. l. pneumatique lithotripsy in which a rigid probe is inserted and pneumatic pressure is applied directly to the calculus.

lithotripter lithotripteur an instrument for crushing calculi in lithotripsy.

lithotriptic lithotriptique dissolving vesical calculi; also, an agent that so acts.

lithotriptor lithotripteur lithotripter.

lithotrite lithotriteur an instrument for crushing a urinary calculus.

lithotrity lithotritie lithotripsy.

lithuresis sable urinaire, petite lithiase urinaire the passage of gravel in the urine.

litmus tournesol a pigment prepared from Rocella tinctoria and other lichens; used as an acidbase (pH) indicator.

litter civière stretcher.

littoral littoral pertaining to the shore of a large body of water.

livedo livedo [L.] a discolored patch on the skin. l. racemosa, l. reticularis l. racemosa a red to blue, netlike mottling of the skin on the limbs and trunk, which becomes more intense on exposure to cold. One type is normal, benign, and transient and other types are chronic, indicative of underlying conditions, and occasionally even ulcerative.

livedoid livédoïde pertaining to livedo.

liver foie 1. the large, dark-red gland in the upper part of the abdomen on the right side, just beneath the diaphragm. See Plate 27. Its functions include storage and filtration of blood, secretion of bile, conversion of sugars into glycogen, and many other metabolic activities. 2. the same gland of certain animals, sometimes used as food or from which pharmaceutical products are prepared. fatty l. stéatose hépatique one with fatty infiltration; the liver is enlarged but of normal consistency. hobnail l. f. clouté one whose surface has naillike points from cirrhosis.

liver phosphorylase phosphorylase du foie the liver isozyme of glycogen phosphorylase; deficiency causes glycogen storage disease, type VI.

liver phosphorylase kinase phosphorylase kinase hépatique the liver isozyme of phosphorylase kinase; deficiency causes phosphorylase b kinase deficiency.

livid livide discolored, as from a contusion or bruise; black and blue.

livor lividité pl. livores [L.] discoloration. l. mortis l. cadavériques discoloration of dependent parts of the body after death.

lixiviation lixiviation separation of soluble from insoluble material by use of an appropriate solvent, and drawing off the solution.

LMA MIGA left mentoanterior (position of fetus).

LMF LMF lymphocyte mitogenic factor.

LMP MIGP left mentoposterior (position of fetus); last menstrual period.

LMT MIGT left mentotransverse (position of fetus).

LNMP LNMP last normal menstrual period.

LNPF LNPF lymph node permeability factor.

LOA OIGA left occipitoanterior (position of fetus).

Loa Loa a genus of filarial nematodes, including L. loa, a West African species that migrates freely throughout the subcutaneous connective tissue, seen especially about the orbit and even under the conjunctiva, and occasionally causing edematous swellings.

load charge the quantity of something measurable carried by an object or organism. allostatic l. c. allostatique, c. de stress term coined as an alternative to stress, referring to environmental challenges that cause an organism to begin efforts to maintain allostasis. viral l. c. virale the number of copies of RNA of a given virus per mL of blood.

loading de charge 1. administering sufficient quantities of a substance to test a subject’s ability to metabolize or absorb it. 2. exertion of lengthening force on a part such as a muscle or ligament.

lobate lobé divided into lobes.

lobation lobaison, lobation the formation of lobes; the state of having lobes. renal l. lobation rénale the appearance on x-ray films of small notches along the surface of the kidney, indicating the location of renal lobes.

lobe lobe 1. a more or less well-defined portion of an organ or gland. 2. one of the main divisions of a tooth crown. Adj.: lobar. caudate l. l. caudé du foie a small lobe of the liver between the inferior vena cava and the left lobe. ear l. l. de l’oreille earlobe. frontal l. l. frontal the rostral (anterior) portion of the cerebral hemisphere. hepatic l’s l. hépatiques the lobes of the liver, designated the right and left and the caudate and quadrate. insular l. l. de l’insula insula. occipital l. l. occipital the most posterior portion of the cerebral hemisphere, forming a small part of its dorsolateral surface. parietal l. l. pariétal the upper central portion of the cerebral hemisphere, between the frontal and occipital lobes, and above the temporal lobe. polyalveolar l. l. polyalvéolaire a congenital disorder characterized in early infancy by far more than the normal number of alveoli in the lung lobes; thereafter, normal multiplication of alveoli does not take place and they become enlarged, i.e., emphysematous. quadrate l. l. carré 1. precuneus. 2. a small lobe of the liver, between the gallbladder on the right, and the left lobe. spigelian l. l. de Spiegel caudate l. of liver. temporal l. l. temporal the lower lateral lobe of the cerebral hemisphere.

lobectomy lobectomie excision of a lobe, as of the lung, brain, or liver.

lobotomy lobotomie incision of a lobe; in psychosurgery, incision of all the fibers of a lobe of the brain. frontal l., prefrontal l. l. frontale incision of the white matter of the frontal lobe with a leukotome passed via a cannula through holes drilled in the skull.

lobulated lobulé made up of lobules.

lobule lobule a small segment or lobe, especially one of the smaller divisions making up a lobe. Adj.: lobular. l’s of epididymis l. épididymaires the wedge-shaped parts of the head of the epididymis, each comprising an efferent ductule of the testis. hepatic l’s l. hépatiques the small vascular units composing the substance of the liver. paracentral l. l. paracentral a lobe on the medial surface of the cerebral hemisphere, continuous with the pre- and postcentral gyri, limited below by the cingulate sulcus. parietal l. l. pariétal one of the two divisions, inferior and superior, of the parietal lobe of the cerebrum. portal l. l. portal a polygonal mass of liver tissue containing portions of three adjacent hepatic lobules, and having a portal vein at its center and a central vein peripherally at each corner. primary l. of lung, respiratory l. lobule pulmonaire primaire terminal respiratory unit. l’s of testis l. du testicule the pyramidal subdivisions of the testicular substance, each with its base against the tunica albuginea of the testis and its apex at the mediastinum, and composed largely of seminiferous tubules.

lobulus lobulus pl. lobuli [L.] lobule.

lobus lobus pl. lobi [L.] lobe.

local local restricted to or pertaining to one spot or part; not general.

localization localisation 1. the determination of the site or place of any process or lesion. 2. restriction to a circumscribed or limited area. 3. the localization in the oocyte or blastomere of materials that will develop into a particular tissue or organ. cerebral l. l. cérébrale determination of areas of the cortex involved in performance of certain functions. germinal l. l. germinale the location on a blastoderm of prospective organs.

locator localisateur a device for determining the site of foreign objects within the body. electroacoustic l. l. électroacoustique a device which amplifies into an audible click the contact of the probe with a solid object in tissue.

lochia lochies a vaginal discharge occurring during the first week or two after childbirth. Adj.: lochial. l. alba lochia alba the final vaginal discharge after childbirth, when the amount of blood is decreased and the leukocytes are increased. l. rubra lochia rubra that occurring immediately after childbirth, consisting almost entirely of blood. l. sanguinolenta lochia sanguinolenta l. serosa. l. serosa lochia serosa the serous vaginal discharge occurring four or five days after childbirth.

lochiorrhagia lochiorrhagie lochiorrhea.

lochiorrhea lochiorrhée an abnormally profuse lochia.

lochioschesis lochiostasis retention of the lochia.

lockjaw trismus 1. tetanus. 2. trismus.

locomotion locomotion movement or the ability to move from one place to another. Adj.: locomotive, locomotor.

locoregional locorégional limited to a localized area, as contrasted with systemic or metastatic.

loculus pl. loculi [L.] 1. locule a small space or cavity. 2. loge an enlargement in the uterus in some mammals, containing an embryo. Adj.: locular.

locum locum [L.] place. l. tenens, l. tenent remplaçant a practitioner who temporarily takes the place of another.

locus locus pl. loci [L.] 1. place; site. 2. in genetics, the specific site of a gene on a chromosome. l. caeruleus l. cœruleus a pigmented eminence in the superior angle of the floor of the fourth ventricle of the brain.

lodoxamide lodoxamide a mast cell stabilizer and antiallergic; applied topically to the eye as the tromethamine salt for the treatment of allergen-induced conjunctivitis, keratitis, and keratoconjunctivitis.

logadectomy logadectomie excision of a portion of the conjunctiva.

logamnesia aphasie réceptrice receptive aphasia.

logaphasia aphémie motor aphasia.

log(o)- log(o)- word element [Gr.], words; speech.

logoclonia logoclonie spasmodic repetition of words or parts of words, particularly the end syllables; often occurring in Alzheimer disease. Cf. stuttering.

logopathy logopathie speech disorder.

logopedics logopédie the study and treatment of speech defects.

logoplegia logoplégie paralysis of the speech organs.

logorrhea logorrhée, verbomanie pressured speech; excessive and rapid speech, seen in certain mental disorders.

logospasm 1. logoclonie logoclonia. 2. répétition spasmodique stuttering.

-logy -logie word element [Gr.], science; treatise; sum of knowledge in a particular subject.

loiasis loase infection with nematodes of the genus Loa.

loin lombes the part of the back between the thorax and pelvis.

lomefloxacin loméfloxacine a broad-spectrum antibiotic effective against a wide range of aerobic gram-negative and gram-positive organisms; used as the hydrochloride salt.

lomustine lomustine an alkylating agent of the nitrosourea group, used as an antineoplastic in the treatment of Hodgkin disease and brain tumors.

longissimus longissimus [L.] longest.

longitudinalis longitudinalis [L.] lengthwise.

longus longus [L.] long.

loop anse a turn or sharp curve in a cordlike structure. capillary l’s a. capillaires minute endothelial tubes that carry blood in the papillae of the skin. closed l. boucle fermée a type of feedback in which the input to one or more of the subsystems is affected by its own output. l. of Henle, Henle l. a. du néphron the long U-shaped part of the renal tubule, extending through the medulla from the end of the proximal convoluted tubule. It begins with a descending limb (comprising the proximal straight tubule and the thin tubule), followed by the ascending limb (the distal straight tubule), and ending at the distal convoluted tubule. open l. boucle ouverte a system in which an input alters the output, but the output has no effect on the input.

loosening relâchement freeing from restraint or strictness. l. of associations r. des associations d’idées in psychiatry, a disorder of thinking in which associations of ideas become so shortened, fragmented, and disturbed as to lack logical relationship.

LOP OIGP left occipitoposterior (position of fetus).

loperamide lopéramide an antiperistaltic used as the hydrochloride salt as an antidiarrheal and to reduce the volume of discharge from ileostomies.

lophotrichous lophotriche having two or more flagella at one end (of a bacterial cell).

lopinavir lopinavir an antiviral HIV protease inhibitor, used with ritonavir in the treatment of HIV infection.

loracarbef loracarbef a carbacephem antibiotic closely related to cefaclor and having similar antibacterial actions and uses.

loratadine loratadine a nonsedating antihistamine used in the treatment of allergic rhinitis, chronic idiopathic urticaria, and asthma.

lorazepam lorazépam a benzodiazepine used as an antianxiety agent, sedative-hypnotic, preanesthetic medication, and anticonvulsant.

lordosis lordose 1. the anterior concavity in the curvature of the lumbar and cervical spine as viewed from the side. 2. abnormal increase in this curvature.

losartan losartan an angiotensin II receptor antagonist, used as an antihypertensive; used as the potassium salt.

LOT OIGT left occipitotransverse (position of fetus).

loteprednol loteprednol a corticosteroid applied topically to the conjunctiva in the treatment of seasonal allergic conjunctivitis, postoperative inflammation, and ocular inflammatory disorders.

lotion lotion a liquid suspension, solution, or emulsion for external application to the body.

loupe loupe [Fr.] a magnifying lens.

louse pou pl. lice any of various parasitic insects; species parasitic on humans are Pediculus humanus capitis (head l.), P. humanus corporis (body, or clothes, l.), and Phthirus pubis (crab, or pubic, l.). Lice are major vectors of typhus, relapsing fever, and trench fever.

lovastatin lovastatine an antihyperlipidemic agent that acts by inhibiting cholesterol synthesis, used in the treatment of hypercholesterolemia and other forms of dyslipidemia and to lower the risks associated with atherosclerosis and coronary heart disease.

low-grade bas grade (de) occurring near the low end of a range, as of a fever or malignancy.

loxapine loxapine a tricyclic dibenzoxazepine derivative used as the succinate and hydrochloride salts as an antipsychotic.

loxoscelism loxoscelisme a morbid condition due to the bite of the spiders Loxosceles laeta and L. reclusa, beginning with a painful erythematous vesicle and progressing to a gangrenous slough of the affected area.

loxotomy loxotomie oval amputation.

lozenge [Fr.] 1. pastille troche; a discoid-shaped, solid, medicinal preparation for solution in the mouth, consisting of an active ingredient incorporated in a suitably flavored base. 2. losange a triangular area of tissue marked for excision in plastic surgery.

Lp(a) Lp(a) see under lipoprotein.

LPN LPN licensed practical nurse.

LPV LPV lymphotropic papovavirus.

LSA SIGA left sacroanterior (position of fetus).

LScA position épaule gauche en dorsoantérieure left scapuloanterior (position of fetus).

LScP position épaule gauche en dorsopostérieure left scapuloposterior (position of fetus).

LSD LSD lysergic acid diethylamide.

LSP SIGP left sacroposterior (position of fetus).

L-spine vertèbres lombaires lumbar spine.

LST SIGT left sacrotransverse (position of fetus).

LTF LTF lymphocyte transforming factor.

Lu Lu lutetium.

lubb-dupp boum-tac syllables used to represent the first and second heart sounds.

lubricant lubrifiant a substance applied as a surface film to reduce friction between moving parts.

lucidity lucidité clearness of mind. Adj.: lucid.

lues luès syphilis. Adj.: luetic.

lumbago lumbago pain in the lumbar region.

lumbar lombaire pertaining to the loins.

lumbarization lombarisation nonfusion of the first and second segments of the sacrum so that there is one additional articulated vertebra, the sacrum consisting of only four segments.

lumb(o)- lomb(o)- word element [L.], loin.

lumbocostal lombocostal pertaining to the loin and ribs.

lumbodynia lombalgie lumbago.

lumboinguinal lombo-inguinal pertaining to the loin and groin.

lumbosacral lombosacral pertaining to the loins and sacrum.

lumbricide lombricide ascaricide.

lumbricoid lombricoïde resembling an earthworm; said particularly of Ascaris lumbricoides.

lumbricus lombric pl. lumbrici [L.] any member of the genus Lumbricus, the earthworms.

lumbus lumbus [L.] loin.

lumen pl. lumina [L.] 1. lumière the cavity or channel within a tube or tubular organ. 2. lumen the SI unit of luminous flux; it is the light emitted in a unit solid angle by a uniform point source with luminous intensity of one candela. Adj.: luminal. residual l. l. résiduelle the remains of the Rathke pouch, between the distal and intermediate parts of the pituitary gland.

luminescence luminescence the property of giving off light without a corresponding degree of heat.

luminophor luminophore a chemical group which gives the property of luminescence to organic compounds.

lumirhodopsin lumirhodopsine an intermediate product of exposure of rhodopsin to light.

lumpectomy 1. chirurgie mammaire conservatrice surgical excision of only the palpable lesion in carcinoma of the breast. 2. lumpectomie surgical removal of a mass.

lunate 1. lunaire moon-shaped or crescentic. 2. semi-lunaire lunate bone.

lung poumon the organ of respiration; either of the pair of organs that effect aeration of blood, lying on either side of the heart within the chest cavity. See Plates 25 and 26. black l. anthracose pneumoconiosis of coal workers. brown l. byssinose byssinosis. farmer’s l. maladie du p. de fermier hypersensitivity pneumonitis from inhalation of moldy hay dust. humidifier l. maladie des humidificateurs, maladie des climatiseurs hypersensitivity pneumonitis caused by breathing air that has passed through humidifiers, dehumidifiers, or air conditioners contaminated by certain fungi, amebas, or thermophilic actinomycetes. iron l. p. d’acier popular name for Drinker respirator. pigeon breeder’s l. maladie des éleveurs d’oiseaux hypersensitivity pneumonitis from inhalation of particles of bird feces by those who work closely with pigeons or other birds; it may eventually result in pulmonary fibrosis. white l. p. blanc pneumonia alba.

lungworm ver pulmonaire any parasitic worm that invades the lungs, e.g., Paragonimus westermani in humans.

lunula lunule pl. lunulae [L.] a small, crescentic or moon-shaped area or structure, e.g., the white area at the base of the nail of a finger or toe, or one of the segments of the semilunar valves of the heart.

lupoid lupoïde pertaining to or resembling lupus.

lupus lupus any of a group of skin diseases in which the lesions are characteristically eroded. chilblain l. erythematosus l. érythémateux à engelures a form due to cold-induced microvascular injury, aggravated by cold; early lesions resemble chilblains but later the condition resembles discoid lupus erythematosus. cutaneous l. erythematosus l. érythémateux cutané one of the two main forms of lupus erythematosus, in which the skin may be either the only or the first organ or system involved. It is usually classified as either chronic, subacute, or acute. discoid l. erythematosus (DLE) l. érythémateux chronique a chronic form of cutaneous lupus erythematosus, with red macules covered by scanty adherent scales that fall off and leave scars; lesions often form a butterfly pattern over the bridge of the nose and cheeks, but other areas may also be involved. drug-induced l. l. médicamenteux a syndrome similar to systemic lupus erythematosus, caused by prolonged use of certain drugs, such as hydralazine, isoniazid, various anticonvulsants, or procainamide. l. erythematosus (LE) l. érythémateuxa group of chronic connective tissue diseases, usually classified as either cutaneous l. erythematosus or systemic l. erythematosus. l. erythematosus profundus l. érythémateux profond cutaneous lupus erythematosus with deep brawny indurations or subcutaneous nodules on the skin; the overlying skin may be erythematous, atrophic, and ulcerated and on healing may leave a depressed scar. l. erythematosus tumidus l. erythematosus tumidus a variant of the discoid or systemic type in which lesions are raised red, purple, or brown plaques. hypertrophic l. erythematosus l. érythémateux hypertrophique a form of the discoid type having verrucous hyperkeratotic lesions. l. miliaris disseminatus faciei l. érythémateux aigu disséminé a form marked by discrete, superficial nodules on the face, particularly the eyelids, upper lip, chin, and nostrils. neonatal l. l. néonatal a rash resembling discoid lupus, sometimes with systemic abnormalities such as heart block or hepatosplenomegaly, in infants born to mothers with systemic lupus erythematosus; it is usually benign and self-limited. l. pernio l. pernio 1. a cutaneous manifestation of sarcoidosis consisting of smooth, shiny, purple plaques on the ears, forehead, nose, and digits, often with bone cysts. 2. chilblain l. erythematosus. systemic l. erythematosus (SLE) l. érythémateux systémique a chronic generalized connective tissue disorder, ranging from mild to fulminating, marked by skin eruptions, arthralgia, arthritis, leukopenia, anemia, visceral lesions, neurologic manifestations, lymphadenopathy, fever, and other constitutional symptoms. There may also be abnormal immunologic phenomena such as hypergammaglobulinemia, hypocomplementemia, antigen-antibody complexes, antinuclear antibodies, and LE cells. l. vulgaris l. vulgaire the most common, severe form of tuberculosis of the skin, usually on the face, with red-brown patches of nodules in the dermis that progressively spread peripherally leaving central atrophy and later ulceration, scarring, and destruction of cartilage in involved sites.

lute 1. lut a substance such as cement, wax, or clay that coats a surface or joint area to make a tight seal. 2. luter to coat or seal with such a substance.

luteal lutéal pertaining to or having the properties of the corpus luteum or its active principle.

lutein lutéine 1. a lipochrome from the corpus luteum, fat cells, and egg yolk. 2. any lipochrome.

luteinic lutéinique 1. pertaining to lutein. 2. luteal. 3. pertaining to luteinization.

luteinization lutéinisation the process by which a postovulatory ovarian follicle transforms into a corpus luteum through vascularization, follicular cell hypertrophy, and lipid accumulation, the latter in some species giving the yellow color indicated by the term.

luteolysis lutéolyse degeneration of the corpus luteum. Adj.: luteolytic.

luteoma lutéinome 1. a luteinized granulosatheca cell tumor. 2. nodular hyperplasia of ovarian lutein cells sometimes occurring in the last trimester of pregnancy.

luteotropic lutéotrope stimulating formation of the corpus luteum.

lutetium (Lu) lutécium chemical element (see Table of Elements), at. no. 71.

Lutzomyia Lutzomyia a genus of sandflies of the family Psychodidae, the females of which suck blood. Various species are vectors of leishmaniasis in the New World.

lux (lx) lux the SI unit of illumination, being 1 lumen per square meter.

luxation luxation dislocation.

luxuriant luxuriant growing freely or excessively.

LVAD LVAD left ventricular assist device; see ventricular assist device, under device.

LVN LVN licensed vocational nurse.

Lw Lw lawrencium.

lyase lyase any of a class of enzymes that remove groups from their substrates (other than by hydrolysis or oxidation), leaving double bonds, or that conversely add groups to double bonds.

lycanthropy lycanthropie delusion in which the patient believes he or she is a wolf or other animal or can change into one.

lycopene lycopène the red carotenoid pigment of tomatoes and various berries and fruits.

lycoperdonosis lycoperdonose hypersensitivity pneumonitis due to inhalation of spores of the puffball fungus, Lycoperdon.

lying-in 1. post-natal puerperal. 2. couches puerperium.

lymph lymphe a transparent, usually slightly yellow, often opalescent liquid found within the lymphatic vessels, and collected from tissues in all parts of the body and returned to the blood via the lymphatic system. Its cellular component consists chiefly of lymphocytes. aplastic l., corpuscular l. l. aplasique lymph that contains an excess of leukocytes and does not tend to become organized. euplastic l., fibrinous l. l. euplasique that which tends to coagulate and become organized. inflammatory l. l. inflammatoire lymph produced by inflammation, as in wounds. tissue l. l. tissulaire lymph derived from body tissues and not from the blood.

lympha lympha [L.] lymph.

lymphadenectomy lymphadénectomie surgical excision of a lymph node or nodes.

lymphadenitis lymphadénite inflammation of one or more lymph nodes. cervical l. l. cervicale see under lymphadenopathy. mesenteric l. l. mésentérique inflammation of the mesenteric lymph nodes, causing pain and swelling resembling that of acute appendicitis. tuberculous l. l. tuberculeuse tuberculosis of lymph nodes, usually either cervical or mediastinal. tuberculous cervical l. l. cervicale tuberculeuse tuberculosis of the cervical lymph nodes; formerly called scrofula.

lymphadenocele lymphadénome a cyst of a lymph node.

lymphadenography lymphadénographie radiography of lymph nodes after injection of a contrast medium in a lymphatic vessel.

lymphadenoid lymphadénoïde resembling the tissue of lymph nodes; see under tissue.

lymphadenoma lymphadénome, adénome lymphomateux lymphoma.

lymphadenopathy lymphadénopathie disease of the lymph nodes, usually with swelling. angioimmunoblastic l., angioimmunoblastic l., with dysproteinemia (AILD) l. angio-immunoblastique a systemic lymphoma-like disorder characterized by malaise, generalized lymphadenopathy, and constitutional symptoms; it is a nonmalignant hyperimmune reaction to chronic antigenic stimulation. cervical l. l. cervicale enlarged, inflamed, and tender cervical lymph nodes, seen in certain infectious diseases of children, such as acute infections of the throat. dermatopathic l. l. dermatopathique regional lymph node enlargement associated with melanoderma and other dermatoses marked by chronic erythroderma. immunoblastic l. l. immunoblastique angioimmunoblastic l. mediastinal l. l. médiastinale inflammation and swelling of mediastinal lymph nodes, often caused by some underlying condition such as mediastinitis, a cyst, or a tumor that can be malignant.

lymphagogue lymphagogue an agent promoting the production of lymph.

lymphangiectasia lymphangiectasie lymphangiectasis.

lymphangiectasis lymphangiectasie dilatation of the lymphatic vessels. Adj.: lymphangiectatic.

lymphangioendothelioma lymphangioendothéliome endothelioma of the lymphatic vessels.

lymphangiography lymphangiographie angiography of lymphatic vessels.

lymphangioleiomyomatosis lymphangioléiomyomatose lymphangiomyomatosis.

lymphangiology lymphangiologie the scientific study of the lymphatic system.

lymphangioma lymphangiome a tumor composed of newly formed lymph spaces and channels. cavernous l. l. caverneux 1. a deeply seated lymphangioma composed of cavernous lymphatic spaces and occurring in the head or neck. 2. cystic hygroma. cystic l. l. kystique cystic hygroma.

lymphangiomyomatosis lymphangiomyomatose a progressive disorder of women of child-bearing age, marked by nodular and diffuse interstitial proliferation of smooth muscle in the lungs, lymph nodes, and thoracic duct. Called also lymphangioleiomyomatosis.

lymphangiophlebitis lymphangiophlébite inflammation of the lymphatic vessels and the veins.

lymphangiosarcoma lymphangiosarcome a malignant tumor of vascular endothelial cells arising from lymphatic vessels, usually in a limb that is the site of chronic lymphedema.

lymphangitis lymphangite inflammation of a lymphatic vessel or vessels. Adj.: lymphangitic.

lymphapheresis lymphophérèse lymphocytapheresis.

lymphatic lymphatique 1. pertaining to lymph or to a lymphatic vessel. 2. a lymphatic vessel.

lymphatism lymphatisme status lymphaticus.

lymphatitis lymphatite inflammation of some part of the lymphatic system.

lymphatolysis lymphatolysis destruction of lymphatic tissue. Adj.: lymphatolytic.

lymphectasia lymphectasie distention with lymph.

lymphedema lymphœdème chronic swelling of a part due to accumulation of interstitial fluid (edema) after obstruction of lymphatic vessels or lymph nodes. primary l. l. primaire that not secondary to a known condition; it may be present at birth (congenital l.), appear at adolescence (l. praecox), or appear in adulthood (l. tarda). secondary l. l. secondaire any of the types whose cause is known, such as elephantiasis or types caused by trauma, scarring, or surgery (especially mastectomy).

lymphnoditis lymphadénite lymphadenitis.

lymph(o)- lymph(o)- word element [L.], lymph; lymphoid tissue; lymphatics; lymphocytes.

lymphoblast lymphoblaste a morphologically immature lymphocyte, representing an activated lymphocyte that has been transformed in response to antigenic stimulation. Adj.: lymphoblastic.

lymphoblastoma lymphoblastome lymphoblastic lymphoma.

lymphoblastosis lymphoblastose an excess of lymphoblasts in the blood.

Lymphocryptovirus Lymphocryptovirus Epstein-Barr-like viruses; a genus of viruses of the subfamily Gammaherpesvirinae containing both animal and human pathogens, including Epstein-Barr virus and Marek disease virus.

lymphocytapheresis lymphocytaphérèse the selective removal of lymphocytes from withdrawn blood, which is then retransfused into the donor.

lymphocyte lymphocyte a mononuclear, nongranular leukocyte having a deeply staining nucleus containing dense chromatin and a pale-blue-staining cytoplasm. Chiefly a product of lymphoid tissue, it participates in immunity. Adj.: lymphocytic. B l’s l. B B cells, bursa-dependent lymphocytes; the precursors of antibodyproducing cells (plasma cells) and the cells primarily responsible for humoral immunity. cytotoxic T l’s (CTL) l. cytotoxiques T differentiated T lymphocytes that can recognize and lyse target cells bearing specific antigens; they are important in graft rejection and killing of tumor cells and virus-infected host cells. T l’s l. T T cells, thymus-dependent lymphocytes; those derived from precursors that migrate to the thymus, where they differentiate under the influence the thyroid hormones and acquire their characteristic cell-surface markers; they are responsible for cell-mediated immunity and delayed hypersensitivity.

lymphocytoblast lymphoblaste lymphoblast.

lymphocytoma lymphocytome well-differentiated lymphocytic malignant lymphoma. l. cutis lymphocytoma cutis cutaneous lymphoid hyperplasia.

lymphocytopenia lymphocytopénie lymphopenia; reduction of the number of lymphocytes in the blood.

lymphocytopheresis lymphocytophérèse lymphocytapheresis.

lymphocytosis lymphocytose an excess of normal lymphocytes in the blood or an effusion.

lymphocytotoxicity lymphocytotoxicité the quality or capability of lysing lymphocytes, as in procedures in which lymphocytes having a specific cell surface antigen are lysed when incubated with antisera and complement.

lymphoduct canal lymphatique lymphatic vessel.

lymphoepithelioma lymphoépithéliome a pleomorphic, poorly differentiated carcinoma arising from modified epithelium overlying lymphoid tissue of the nasopharynx.

lymphogenous lymphogène 1. producing lymph. 2. produced from lymph or in the lymphatics.

lymphoglandula nœud lymphatique pl. lymphoglandulae a lymph node.

lymphogranuloma lymphogranulome Hodgkin disease. l. inguinale, l. venereum l. inguinal a venereal infection due to strains of Chlamydia trachomatis, marked by a primary transient ulcerative lesion of the genitals, followed by acute lymphadenopathy. In men, primary infection on the penis usually leads to inguinal lymphadenitis; in women, primary infection of the labia, vagina, or cervix often leads to hemorrhagic proctocolitis, and may progress to ulcerations, rectal strictures, rectovaginal fistulas, and genital elephantiasis.

lymphogranulomatosis lymphogranulomatose European synonym for Hodgkin disease.

lymphography lymphographie radiography of the lymphatic channels and lymph nodes after injection of a radiopaque medium.

lymphoid lymphoïde resembling or pertaining to lymph or tissue of the lymphoid system.

lymphokine lymphokine a general term for soluble protein mediators postulated to be released by sensitized lymphocytes on contact with antigen, and believed to play a role in macrophage activation, lymphocyte transformation, and cell-mediated immunity.

lymphokinesis lymphokinésie 1. movement of endolymph in the semicircular canals. 2. the circulation of lymph in the body.

lympholytic lympholytique causing destruction of lymphocytes.

lymphoma lymphome any neoplastic disorder of lymphoid tissue. Often used to denote malignant l., classifications of which are based on predominant cell type and degree of differentiation; various categories may be subdivided into nodular and diffuse types depending on the predominant pattern of cell arrangement. adult T-cell l., adult T-cell leukemia/l. l. T de l’adulte see under leukemia. B-cell l. l. B any in a large group of non-Hodgkin lymphomas characterized by malignant transformation of the B lymphocytes. B-cell monocytoid l. l. B monocytoïde a low-grade lymphoma in which cells resemble those of hairy cell leukemia. Burkitt l. l. (ou tumeur) de Burkitt a form of small noncleaved-cell lymphoma, usually occurring in Africa, manifested usually as a large osteolytic lesion in the jaw or as an abdominal mass; Epstein-Barr virus has been implicated as a causative agent. centrocytic l. l. centrocytique mantle cell l. convoluted T-cell l. l. à cellules T à noyau circonvoluté lymphoblastic lymphoma with markedly convoluted nuclei. cutaneous T-cell l. l. T cutané a group of lymphomas exhibiting both clonal expansion of malignant T lymphocytes and malignant infiltration of the skin. The lymphocytes are arrested at varying stages of differentiation into helper cells, and skin infiltration is often the chief or only manifestation of disease. follicular l. l. nodulaire any of several types of non-Hodgkin lymphoma in which the lymphomatous cells are clustered into nodules or follicles. follicular center cell l. l. à noyau clivé centrocytique B-cell lymphoma classified by the similarity of the cell size and nuclear characteristics to those of normal follicular center cells; the four previous subtypes are scattered among several types of follicular and diffuse lymphomas. giant follicular l. l. nodulaire géant follicular l. histiocytic l. l. histiocytaire a rare type of non-Hodgkin lymphoma characterized by the presence of large tumor cells resembling histiocytes morphologically but considered to be of lymphoid origin. Hodgkin l. l. de Hodgkin see under disease. intermediate lymphocytic l. l. lymphocytaire intermédiaire mantle cell l. large cell l. l. à larges cellules any of several types of lymphoma characterized by the formation of one or more types of malignant large lymphocytes, such as large cleaved or noncleaved follicular center cells, in a diffuse pattern. large cell, immunoblastic l. l. immunoblastique à larges cellules a highly malignant type of non-Hodgkin lymphoma characterized by large lymphoblasts (B or T lymphoblasts or a mixture) resembling histiocytes and having a diffuse pattern of infiltration. Lennert l. l. de Lennert a type of non-Hodgkin lymphoma with a high content of epithelioid histiocytes and frequently with bone marrow involvement. lymphoblastic l. l. lymphoblastique a highly malignant type of non-Hodgkin lymphoma composed of a diffuse, relatively uniform proliferation of cells with round or convoluted nuclei and scanty cytoplasm. malignant l. l. malin a group of malignancies characterized by the proliferation of cells native to the lymphoid tissues, i.e., lymphocytes, histiocytes, and their precursors and derivatives; the group is divided into two major clinicopathologic categories: Hodgkin disease and non-Hodgkin lymphoma. mantle cell l., mantle zone l. l. des cellules du manteau a rare form of non-Hodgkin lymphoma having a usually diffuse pattern with both small lymphocytes and small cleaved cells. marginal zone l. l. de la zone marginale a group of related B-cell neoplasms that involve the lymphoid tissues in the marginal zone. mixed lymphocytic-histiocytic l. l. mixte lymphocytaire histiocytaire non-Hodgkin lymphoma characterized by a mixed population of cells, the smaller cells resembling lymphocytes and the larger ones histiocytes. nodular l. l. nodulaire follicular l. non-Hodgkin l. l. non hodgkinien a heterogeneous group of malignant lymphomas, the only common feature being an absence of the giant Reed-Sternberg cells characteristic of Hodgkin disease. primary effusion l. l. d’effusion primaire a B-cell lymphoma associated with human herpesvirus 8 infection, characterized by the occurrence of lymphomatous effusions in body cavities without the presence of a solid tumor. small B-cell l. l. à petites cellules B the usual type of small lymphocytic lymphoma, having predominantly B lymphocytes. small cleaved cell l. l. à petites cellules clivées a group of non-Hodgkin lymphomas characterized by the formation of malignant small cleaved follicular center cells, with either a follicular or diffuse pattern. small lymphocytic l. petit l. lymphocytaire a diffuse form of non-Hodgkin lymphoma representing the neoplastic proliferation of well-differentiated B lymphocytes, with focal lymph node enlargement or generalized lymphadenopathy and splenomegaly. small noncleaved cell l. l. à petites cellules non clivées a highly malignant type of non-Hodgkin lymphoma characterized by the formation of small noncleaved follicular center cells, usually in a diffuse pattern. T-cell l. l. T any in a heterogeneous group of lymphoid neoplasms representing malignant transformation of T lymphocytes. undifferentiated l. l. non différencié small noncleaved cell l.

lymphomatosis lymphomatose the formation of multiple lymphomas in the body.

lymphomyxoma lymphome bénin any benign growth consisting of adenoid tissue.

lymphonodus lymphonodus pl. lymphonodi Lymph node.

lymphopathy lymphopathie any disease of the lymphatic system.

lymphopenia lymphopénie lymphocytopenia.

lymphoplasmapheresis lymphoplasmaphérèse selective separation and removal of plasma and lymphocytes from withdrawn blood, the remainder of the blood then being retransfused to the donor.

lymphoproliferative lymphoprolifératif pertaining to or characterized by proliferation of the cells of the lymphoreticular system.

lymphoreticular lymphoréticulaire pertaining to the cells or tissues of both the lymphoid and reticuloendothelial systems.

lymphoreticulosis lymphoréticulose proliferation of the reticuloendothelial cells of the lymph nodes. benign l. l. bénigne d’inoculation cat-scratch disease.

lymphorrhagia lymphorrhagie lymphorrhea.

lymphorrhea lymphorrhée flow of lymph from cut or ruptured lymph vessels.

lymphosarcoma lymphosarcome a general term applied to malignant neoplastic disorders of lymphoid tissue, but not including Hodgkin disease; see lymphoma.

lymphoscintigraphy lymphoscintigraphie scintigraphic detection of metastatic tumor in radioactively labeled lymph nodes, particularly that using radioactively labeled technetium colloid (radiocolloid l.).

lymphostasis lymphostase stoppage of lymph flow.

lymphotaxis lymphotaxie the property of attracting or repulsing lymphocytes.

lymphotoxin lymphotoxine tumor necrosis factor β; a lymphokine produced by activated T lymphocytes that it inhibits growth of tumors and blocks transformation of cells.

lymphotropic lymphotrope having an affinity for lymphatic tissue.

lyonization théorie de l’inactivation de l’X the process by which or the condition in which all X chromosomes of the somatic cells in excess of one are inactivated on a random basis.

lyophilic lyophile having an affinity for, or stable in, solution.

lyophilization lyophilisation the creation of a stable preparation of a biological substance by rapid freezing and dehydration of the frozen product under high vacuum.

lyophobic lyophobe not having an affinity for, or unstable in, solution.

lyotropic lyotrope lyophilic.

lypressin lypressine a synthetic preparation of lysine vasopressin, used as an antidiuretic and vasoconstrictor in the treatment of central diabetes insipidus.

lyse 1. lyser to cause or produce disintegration of a compound, substance, or cell. 2. lyser (se) to undergo lysis.

Lys Lys lysine.

lysergic acid diethylamide (LSO) diéthylamide de l’acide lysergique a widely abused psychomimetic derived from lysergic acid, with both sympathomimetic and serotoninergic blocking effects. Side effects can include ataxia, fever, hyperreflexia, mydriasis, piloerection, tremor, nausea and vomiting, visual perception disorders, and varying psychiatric disturbances. Anxiety may develop into acute panic reactions, and a persistent toxic psychotic state may result.

lysergide lysergide lysergic acid diethylamide.

lysin lysine 1. an antibody that causes complement-dependent lysis of cells; often used with a prefix indicating the target cells, e.g., hemolysin. 2. any substance that causes cytolysis.

lysine (Lys, K) lysine a naturally occurring, essential amino acid, necessary for optimal growth in human infants and for maintenance of nitrogen equilibrium in adults. The acetate and hydrochloride salts are used in dietary supplementation and the hydrochloride salt is used in the treatment of severe metabolic alkalosis refractory to treatment.

lysinogen lysinogène an antigenic substance capable of inducing the formation of lysins.

lysinuria lysinurie an aminoaciduria consisting of excessive lysine in the urine, as in hyperlysinemia. Adj.: lysinuric.

lysis lyse 1. destruction or decomposition, as of a cell or other substance, under influence of a specific agent. 2. mobilization of an organ by division of restraining adhesions. 3. gradual abatement of the symptoms of a disease.

-lysis -lyse word element [Gr.], dissolution, reduction, abatement, relief.

lysogen lysogène 1. an agent that induces lysis. 2. lysinogen. 3. a lysogenized bacterium.

lysogenic 1. lysogène producing lysins or causing lysis. 2. lysogénique pertaining to lysogeny.

lysogenicity lysogénie 1. the ability to produce lysins or cause lysis. 2. the potentiality of a bacterium to produce phage. 3. the specific association of the phage genome (prophage) with the bacterial genome in such a way that only a few, if any, phage genes are transcribed.

lysogeny lysogénie the phenomenon in which a bacterium is infected by a temperate bacteriophage, the viral DNA is integrated in the chromosome of the host cell and replicated along with the host chromosome for many generations (the lysogenic cycle), and then production of virions and lysis of host cells (the lytic cycle) begins again.

lysosomal α-glucosidase α-glucosidase lysosomale acid maltase.

lysosome lysosome a membrane-bound cytoplasmic organelle that contains hydrolytic enzymes and is involved in intracellular digestion. Adj.: lysosomal. secondary l. l. secondaire one that has fused with a phagosome or pinosome, bringing hydrolases in contact with the ingested material, which is then digested.

lysozyme lysozyme an enzyme present in saliva, tears, egg white, and many animal fluids, functioning as an antibacterial agent by catalyzing the hydrolysis of specific glycosidic linkages in peptidoglycans and chitin, breaking down some bacterial cell walls.

Lyssavirus Lyssavirus rabies-like viruses; a genus of viruses of the family Rhabdoviridae comprising the rabies virus and other related African viruses infecting mammals and arthropods.

lyssophobia lyssophobie irrational fear of rabies.

lytic lytique 1. pertaining to lysis or to a lysin. 2. producing lysis.

-lytic -lytique a word termination denoting lysis of the substance indicated by the stem to which it is affixed.

lyze lyse lyse.

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