|Medical Dictionary - Dictionary of Medicine and Human Biology|
Pertaining to or characterized by leukocytes. SYN: leukocytal.
A nonspecific term for any immature cell from which a leukocyte develops, including lymphoblast, myeloblast, and the like. [leukocyte + G. blastos, germ]
Karyorrhexis of leukocytes. [leuko- + G. kytos, cell, + klasia, a breaking]
The formation and development of leukocytes. [leukocyte + G. genesis, production]
Resembling a leukocyte. [leukocyte + G. eidos, resemblance]
Any substance (including lytic antibody) that causes dissolution of leukocytes. SYN: leukolysin.
Dissolution or lysis of leukocytes. SYN: leukolysis. [leukocyte + G. lysis, dissolution]
Pertaining to, causing, or manifesting leukocytolysis. SYN: leukolytic.
Obsolete term for a fairly well circumscribed, nodular, dense accumulation of leukocytes. [leukocyte + G. -oma, tumor]
A standardized glass slide that is suitably ruled for counting the leukocytes in a measured volume of accurately diluted blood (or other specimens). [leukocyte + G. metron, measure]
Movement of leukocytes from the lumens of blood vessels, through serous membranes, or in the tissues. [leukocyte + G. plane, a wandering]
SYN: leukopoiesis. [leukocyte + G. poiesis, a making]
An abnormally large number of leukocytes, as observed in acute infections, inflammation, hemorrhage, and other conditions. A white blood cell count of 10,000 or more per mm3 usually indicates l. Most examples of l. represent a disproportionate increase in the number of cells in the neutrophilic series, and the term is frequently used synonymously with the designation neutrophilia. L. of 15,000–25,000/mm3 is frequently observed in various pathologic conditions, and values as high as 40,000 are not unusual; occasionally, as in some examples of leukemoid reactions, white blood cell counts may range up to 100,000/mm3. [leukocyte + G. -osis, condition] absolute l. an actual increase in the total number of leukocytes in the circulating blood, as distinguished from a relative increase (such as that observed in dehydration). agonal l. SYN: terminal l.. basophilic l. the presence of an abnormally large number of basophilic granulocytes in the blood. SYN: basocytosis. digestive l. l. occurring normally after ingestion of food. distribution l. an abnormally large proportion of one or more types of leukocytes. emotional l. an abnormally high white blood cell count that is thought to be related only to an emotional disturbance. eosinophilic l. a form of relative l. in which the greatest proportionate increase is in the eosinophils. SYN: eosinophilia. lymphocytic l. SYN: lymphocytosis. monocytic l. SYN: monocytosis. neutrophilic l. SYN: neutrophilia. l. of the newborn an apparently “physiologic” l. usually observed in newborn infants, in whom the white blood cell counts are usually greater than 10,000/mm3, and sometimes range to 45,000/mm3, resulting chiefly from increased numbers of neutrophils (especially single and bilobed forms). On the third or fourth day of life, the count generally decreases rapidly, and then fluctuates for several days; beginning about the fourth week of life, a relative lymphocytosis is observed, and this normally continues for a few years. physiologic l. any form of l. that is associated with apparently normal situations and that is not directly related to a pathologic condition; e.g., the temporary increase in the total number of white blood cells that may occur during a single day, or from day to day, as well as in the newborn period, during childhood, after strenuous exercise, during attacks of paroxysmal tachycardia, and in association with various other situations. relative l. an increased proportion of one or more types of leukocytes in the circulating blood, without an actual increase in the total number of white blood cells. terminal l. one that occurs in a person just prior to death, especially in one who has a “slow death.” SYN: agonal l..
Pertaining to, characterized by, or causing leukocytotaxia. SYN: leukocytactic, leukotactic.
1. The active ameboid movement of leukocytes, especially the neutrophilic granulocytes, either toward (positive l.) or away from (negative l.) certain microorganisms as well as various substances frequently formed in inflamed tissue. 2. The property of attracting or repelling leukocytes. SYN: leukocytaxia, leukocytaxis, leukotaxia, leukotaxis. [leukocyte + G. taxis, arrangement]
Any substance that causes degeneration and necrosis of leukocytes, including leukolysin and leukocidin. SYN: leukotoxin. [leukocyte + G. toxikon, poison]
The presence of leukocytes in urine that is recently voided or collected by means of a catheter. [leukocyte + G. ouron, urine]
An absence of pigment, partial or total, in the skin. SYN: hypomelanosis, leukopathia, leukopathy. [leuko- + G. derma, skin] acquired l. SYN: vitiligo. l. acquisitum centrifugum SYN: halo nevus. l. colli SYN: syphilitic l.. syphilitic l. a fading of the roseola of secondary syphilis, leaving reticulated depigmented and hyperpigmented areas located chiefly on the sides of the neck. SYN: l. colli, melanoleukoderma colli.
Relating to or resembling leukoderma.
The condition of having white teeth. [leuko- + G. odous, tooth]
SYN: leukodystrophy. l. cerebri progressiva SYN: leukodystrophy.
Term for a group of white matter diseases, some familial, characterized by progressive cerebral deterioration usually in early life, and pathologically by primary absence or degeneration of the myelin of the central and peripheral nervous systems with glial reaction; probably related to a defect in lipid metabolism; most leukodystrophies are autosomal recessive, several X-linked recessive, and a few autosomal dominant. SEE ALSO: Canavan disease. SYN: leukodystrophia cerebri progressiva, leukodystrophia, sclerosis of white matter. [leuko- + G. dys, bad, + trophe, nourishment] adrenal l. sudanophilic l. with bronzing of skin and adrenal atrophy. A metabolic disorder of young males, characterized by widespread myelin degeneration and associated adrenal insufficiency. The myelin degeneration is massive in various portions of the brain and sometimes the spinal cord, with the accumulation of degradation products of myelin in macrophages: sudanophilic demyelination; atrophy is present in the adrenal glands and testes, and markedly increased amounts of very long-chain fatty acid are present in both the brain and adrenal glands. Symptoms include bronzing of the skin, dysarthria, cortical blindness, bilateral hemiplegia, pseudobulbar paralysis, and progressive dementia. Probably sex-linked recessive inheritance. globoid cell l. [MIM*245200] a metabolic disorder of infancy or early childhood characterized by spasticity, seizures, and rapidly progressive cerebral degeneration, massive loss of myelin, severe astrocytic gliosis, and infiltration of the white matter with characteristic multinucleate globoid cells; metabolically there is gross deficiency of lysosomal cerebrosidase (galactosylceramide β-galactosidase); autosomal recessive inheritance, caused by mutation in the gene encoding glycosylceramidase (GALC) on 14q. SYN: diffuse infantile familial sclerosis, galactosylceramide lipoidosis, Krabbe disease. metachromatic l. [MIM*250100] a metabolic disorder, with onset usually in the second year of life and death often before 5 years, with loss of myelin and accumulation of metachromatic lipids (galactosyl sulfatidates) in the white matter of the central and peripheral nervous systems leading to motor symptoms, paralysis, convulsions, and progressive cerebral deterioration;. Autosomal recessive inheritance [MIM*249900 and MIM*250100], caused by mutation in either the arylsulfatase A gene (ARSA) on 22q or the prosaposin gene (PSAP) on 10q. There is a dominant form occurring in adults [MIM*156310]. SYN: arylsulfatase A deficiency, sulfatide lipidosis. l. with diffuse Rosenthal fiber formation a metabolic disorder whose onset can be in infancy, adolescence, or adulthood; characterized pathologically by widespread cerebral demyelination with astrocyte and primitive oligodendroglial cell proliferation; refractile Rosenthal fibers result from the degeneration of these proliferating cells; etiology unknown, but possibly due to a metabolic defect of astrocytes; sex-linked recessive disorder.
Encephalitis restricted to the white matter. acute epidemic l. a disease characterized by acute onset of fever, followed by convulsions, delirium, and coma, and associated with perivascular demyelination and hemorrhagic foci in the central nervous system. SYN: acute primary hemorrhagic meningoencephalitis, Strümpell disease (2) . acute hemorrhagic l. SYN: acute necrotizing hemorrhagic encephalomyelitis. acute necrotizing hemorrhagic l. SYN: acute necrotizing hemorrhagic encephalomyelitis. sclerosing l. SYN: subacute sclerosing panencephalitis. subacute sclerosing l. SYN: subacute sclerosing panencephalitis.
White matter changes first described in children with leukemia, associated with radiation and chemotherapy injury, often associated with methotrexate; pathologically characterized by diffuse reactive astrocytosis with multiple areas of necrotic foci without inflammation. [leuko- + G. enkephalos, brain, + pathos, suffering] progressive multifocal l. (PML) a rare, subacute, afebrile disease characterized by areas of demyelinization surrounded by markedly altered neuroglia, including inclusion bodies in glial cells; it occurs usually in individuals with AIDS, leukemia, lymphoma, or other debilitating diseases, or in those who have been receiving immunosuppressive treatment. Caused by JC virus, a human polyoma virus. SYN: progressive subcortical encephalopathy.
Any anemic condition resulting from space-occupying lesions in the bone marrow; the circulating blood contains immature cells of the granulocytic series and nucleated red blood cells, frequently in numbers that are disproportionately large in relation to the degree of anemia. SYN: leukoerythroblastic anemia, myelophthisic anemia, myelopathic anemia.
Pertaining to leukokinetics. [leukocyte + G. kinetikos, of motion, fr. kineo, to move]
The study of the formation, circulation, and fate of leukocytes, usually by use of a radioactive tracer. [leukocyte + G. kinetikos, of or for putting in motion]
SYN: kraurosis vulvae.
A dense white opacity of the cornea. [G. whiteness, a white spot in the eye, fr. leukos, white] adherent l. a cicatrix of the cornea to which a portion of the iris is attached.
Pertaining to leukoma.
An inflammatory process involving the white matter of the spinal cord. necrotizing hemorrhage l. the pathological substrate responsible for the clinical disorder of acute necrotizing myelitis.
Any systemic disease involving the white matter or the conducting tracts of the spinal cord. [leuko- + G. myelos, marrow, + pathos, suffering]
The total mass of circulating leukocytes as well as the cells and leukopoietic cells from which it originates.
SYN: white gangrene. [leuko- + G. nekrosis, deadness]
The occurrence of smooth-surfaced white spots or patches under the nails, of unknown cause; the decoloration may be total or in the form of lines (striate or transverse l.) or dots (punctate l.). [leuko- + G. onyx (onych-), nail]
leukopathia, leukopathy (loo-ko-path′e-a, loo-kop′a-the)
SYN: leukoderma. [leuko- + G. pathos, disease]
The movement of white blood cells (especially polymorphonuclear leukocytes) through the walls of capillaries and into the tissues. [leuko- + G. pedesis, a leaping]
The antithesis of leukocytosis; any situation in which the total number of leukocytes in the circulating blood is less than normal, the lower limit of which is generally regarded as 4000–5000/mm3. SYN: leukocytopenia. [leuko(cyte) + G. penia, poverty] basophilic l. a decrease in the number of basophilic granulocytes in the circulating blood (difficult to evaluate, owing to the small and variable number normally present). SYN: basocytopenia, basopenia. eosinophilic l. a decrease in the number of eosinophilic granulocytes normally present in the circulating blood. lymphocytic l. SYN: lymphopenia. monocytic l. SYN: monocytopenia. neutrophilic l. SYN: neutropenia.
Pertaining to leukopenia.
A white patch of oral or female genital mucous membrane that cannot be wiped off and cannot be diagnosed clinically as any specific disease entity; in current usage, a clinical term without histologic connotation. SYN: smoker's patches. [leuko- + G. plax, plate] hairy l. a white lesion appearing on the tongue, occasionally on the buccal mucosa, of patients with AIDS; a manifestation of Epstein-Barr virus infection in an immunocompromised host; the lesion appears raised, with a corrugated, shaggy, or “hairy” surface due to keratin projections.Oral hairy l. was first recognized in 1981 as a marker of immunosuppression in male homosexuals with AIDS. The incidence in persons with AIDS is about 20%. Oral hairy l. consists of white vertical folds or ridges, generally along the lateral borders of the tongue, but sometimes on its lower surface or on the buccal mucosa. Unlike the lesions of candidiasis (thrush), the patches cannot be scraped off. The condition is ordinarily asymptomatic, causing neither pain nor alteration of taste. Histologic study shows parakeratosis and koilocytosis with little inflammation. The lesion occasionally progresses to squamous cell carcinoma. Treatment with topical podophyllin or systemic acyclovir usually induces prompt regression of lesions. l. vulvae a clinical term for hyperkeratotic white patches of the vulvar epithelium; biopsy is necessary for specific diagnosis.
Formation and development of the various types of white blood cells. SYN: leukocytopoiesis. [leuko- + G. poiesis, a making]
Pertaining to or characterized by leukopoiesis, as manifested by portions of the bone marrow and reticuloendothelial and lymphoid tissues, which form (respectively) the granulocytes, monocytes, and lymphocytes.
An ill-defined proteolytic enzyme product of polynuclear leukocytes, formed in an area of inflammation, that causes liquefaction of dead tissue.
The colorless nonfluorescing dihydro compound formed by the reduction of riboflavin.
SYN: leukorrhea. [leuko- + G. rhegnymi, to burst forth]
Discharge from the vagina of a white or yellowish viscid fluid containing mucus and pus cells. SYN: leukorrhagia. [leuko- + G. rhoia, flow] menstrual l. intermittent l. recurring at or just before each menstrual period.
Relating to or characterized by leukorrhea.
A cell-free nitrogenous material prepared from injured, acutely degenerating tissue and from inflammatory exudates.
An instrument for performing leukotomy.
Incision into the white matter of the frontal lobe of the brain. [leuko- + G. tome, a cutting] prefrontal l. SYN: prefrontal lobotomy. transorbital l. SYN: transorbital lobotomy.
Whiteness of the hair. [leuko- + G. thrix, hair]
leukotrienes (LT) (loo-ko-tri′enz)
Products of eicosanoid metabolism (usually, arachidonic acid) with postulated physiologic activity such as mediators of inflammation and roles in allergic reactions; they differ from the related prostaglandins and thromboxanes by not having a central ring; so named because they were originally discovered in association with leukocytes and of three conjugated double bonds; letters A through F identify the first six metabolites isolated, with subscript numbers to indicate the number of double bonds ( e.g., leukotriene C4). peptidyl l. l. having one or more amino acids present; e.g., LTC4 is an S-substituted glutathione, LTD4 is an S-substituted cysteinylglycine, LTE4 is an S-substituted cysteine, and LTF4 (also known as γ-glutamyl-LTE4) is an S-substituted γ-glutamylcysteine.
Obsolete term for a former genus composed of the RNA tumor viruses now included in the family Retroviridae.
The epitope for a monoclonal antibody generated to the human histiocytic cell line that localizes to neutrophils, adherent monocytes, and a subgroup of activated T cells.
One of a number of modified tripeptide protease inhibitors from Streptomyces species that inhibits cathepsin B, papain, trypsin, plasmin, and cathepsin D. The most commonly used l. is N-acetylleucylleucylarginal.
leuprolide acetate (loo′pro-lid)
A synthetic nonapeptide analog of naturally occurring gonadotropin-releasing hormone; used in the palliative treatment of advanced prostatic cancer.
SYN: vincristine sulfate.
Maurice, U.S. pathologist, 1908–1994. See L. disease, L. syndrome.
Constantin, Romanian bacteriologist in Paris, 1879–1928. See L. stain.
levallorphan tartrate (lev-a-lor′fan)
The N-allyl analog of levorphanol, antagonistic to the actions of narcotic analgesics; used in the treatment of respiratory depression due to overdosage of narcotics.
Formerly used as an anthelmintic; increases immune responses and is used adjunctively with antineoplastic agents to improve response and suppress recurrence.
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