|| ANATOMY || DISEASES || DRUGS || HEALTH TOPICS || USA HEALTH STATS || CHINA HEALTH STATS || GENOMICS || LABORATORY MICE || LUPUS ||
Medical Dictionary banner
Medical Dictionary - Dictionary of Medicine and Human Biology


Medical Dictionary


A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


lymphoblastoma (lim-fo-blas-to′ma)
SYN: lymphoblastic lymphoma. [lymphoblast + G. -oma, tumor] giant follicular l. SYN: nodular lymphoma.

lymphoblastosis (lim′fo-blas-to′sis)
The presence of lymphoblasts in the peripheral blood; sometimes used as a synonym for acute lymphocytic leukemia. [lymphoblast + G. -osis, condition]

lymphocele (lim′fo-sel)
A cystic mass that contains lymph, usually from diseased or injured lymphatic channels. SYN: lymphocyst. [lympho- + G. kele, tumor]

lymphocerastism (lim-fo-ser′as-tizm)
Obsolete term for the process of formation of cells in the lymphocytic series. [lympho- + G. kerastos, mixed, mingled]

lymphocinesis, lymphocinesia (lim′fo-si-ne′sis, ne-ze-a)
SYN: lymphokinesis.

lymphocyst (lim′fo-sist)
SYN: lymphocele. [lympho- + G. kystis, bladder]

lymphocytapheresis (lim′fo-sit-af-e-re′sis)
Separation and removal of lymphocytes from the withdrawn blood, with the remainder of the blood retransfused into the donor. SYN: lymphapheresis. [lymphocyte + G. aphairesis, a withdrawal]

lymphocyte (lim′fo-sit)
A white blood cell formed in lymphatic tissue throughout the body ( e.g., lymph nodes, spleen, thymus, tonsils, Peyer patches, and sometimes in bone marrow) and in normal adults making up approximately 22–28% of the total number of leukocytes in the circulating blood. Lymphocytes are generally small (7–8 μm), but larger forms are frequent (10–20 μm); with Wright (or a similar) stain, the nucleus is deeply colored (purple-blue), and is composed of dense aggregates of chromatin within a sharply defined nuclear membrane; the nucleus is usually round, but may be slightly indented, and is eccentrically situated within a relatively small amount of light blue cytoplasm that ordinarily contains no granules; especially in larger forms, the cytoplasm may be fairly abundant and include several bright red-violet fine granules; in contrast to granules of the myeloid series of cells, those in lymphocytes do not yield a positive oxidase or peroxidase reaction. Lymphocytes are divided into 2 principal groups, termed T and B cells, based on their surface molecules as well as function. Natural killer cells, which are large granular lymphocytes, represent a small percentage of the l. population. SYN: lymph cell, lympholeukocyte. [lympho- + G. kytos, call] B l. an immunologically important l. that is not thymus-dependent, is of short life, and resembles the bursa-derived l. of birds in that it is responsible for the production of immunoglobulins, i.e., it is the precursor of the plasma cell and expresses immunoglobulins on its surface but does not release them. It does not play a direct role in cell-mediated immunity. SEE ALSO: T l.. SYN: B cell (2) . pre-B l. an early B-lymphoid type cell that is recognized by immunofluorescence as a μ-positive, L-chain-negative bone marrow cell. Rieder l. an abnormal form of l. that has a greatly indented (or lobed), slightly twisted nucleus; such cells are usually observed in certain examples of chronic lymphocytic leukemia. T l. a thymocyte-derived l. of immunologic importance that is long-lived (months to years) and is responsible for cell-mediated immunity. T lymphocytes form rosettes with sheep erythrocytes and, in the presence of transforming agents (mitogens), differentiate and divide. These cells have characteristic CD3 surface markers and may be further divided into subsets according to function, such as helper, cytotoxic, etc. SEE ALSO: B l.. SYN: T cell. transformed l. l. transformation. tumor-infiltrating lymphocytes (TIL, TILS) (lim′fo-sitz) lymphocytes collected from the site of a tumor and exposed to IL-2 in vitro to expand the population. When these cells are injected back into the tumor-bearing host, they will specifically kill the tumor from which they originated.

lymphocythemia (lim′fo-si-the′me-a)
SYN: lymphocytosis.

lymphocytic (lim-fo-sit′ik)
Pertaining to or characterized by lymphocytes.

lymphocytoblast (lim-fo-si′to-blast)
SYN: lymphoblast. [lymphocyte + G. blastos, germ]

lymphocytoma (lim′fo-si-to′ma)
A circumscribed nodule or mass of mature lymphocytes, grossly resembling a neoplasm. [lymphocyte + G. -oma, tumor] benign l. cutis a soft red to violaceous skin nodule often involving the head, caused by dense infiltration of the dermis by lymphocytes and histiocytes, often forming lymphoid follicles, separated from the epidermis by a narrow noninfiltrating layer. SYN: cutaneous pseudolymphoma, Spiegler-Fendt sarcoid.

lymphocytopenia (lim′fo-si-to-pe′ne-a)
SYN: lymphopenia.

lymphocytopoiesis (lim′fo-si-to-poy-e′sis)
The formation of lymphocytes. [lymphocyte + G. poiesis, a making]

lymphocytosis (lim′fo-si-to′sis)
A form of actual or relative leukocytosis in which there is an increase in the number of lymphocytes. SYN: lymphocythemia, lymphocytic leukocytosis.

lymphoderma (lim′fo-der′ma)
A condition resulting from any disease of the cutaneous lymphatic vessels. [lympho- + G. derma, skin]

lymphoduct (lim′fo-dukt)
A lymphatic vessel. See lymph vessels, under vessel. [lympho- + L. ductus, a leading]

lymphogenesis (lim-fo-gen′e-sis)
Lymph production. [lympho- + G. genesis, production]

lymphogenic (lim-fo-jen′ik)
SYN: lymphogenous (1) .

lymphogenous (lim-foj′e-nus)
1. Originating from lymph or the lymphatic system. SYN: lymphogenic. 2. Producing lymph.

lymphoglandula (lim-fo-glan′doo-la)
SYN: lymph node.

lymphogranuloma (lim′fo-gran-u-lo′ma)
Old nonspecific term used with reference to a few basically dissimilar diseases in which the pathologic processes result in granulomas or granulomalike lesions, especially in various groups of lymph nodes (which then become conspicuously enlarged). l. benignum old term for sarcoidosis. l. inguinale SYN: venereal l.. l. malignum old term for Hodgkin disease. Schaumann l. old eponym for sarcoidosis. venereal l., l. venereum a venereal infection usually caused by Chlamydia trachomatis, and characterized by a transient genital ulcer and inguinal adenopathy in the male; in the female, perirectal lymph nodes are involved and rectal stricture is a common occurrence. SYN: Favre-Durand-Nicholas disease, l. inguinale, Nicolas-Favre disease, tropical bubo.

lymphogranulomatosis (lim-fo-gran′u-lo-ma-to′sis)
Any condition characterized by the occurrence of multiple and widely distributed lymphogranulomas.

lymphography (lim-fog′ra-fe)
Visualization of lymphatics (lymphangiography) and lymph nodes (lymphadenography) by radiography following the intralymphatic injection of a contrast medium, usually an iodized oil. [lympho- + grapho, to write]

lymphohistiocytosis (lim′fo-his′te-o-si-to′sis)
Proliferation or infiltration of lymphocytes and histiocytes. familial erythrophagocytic l. (FEL) SYN: familial hemophagocytic l.. familial hemophagocytic l. (FMLH) an extremely rare, usually fatal disease of childhood characterized by multiorgan infiltration with activated macrophages and lymphocytes. The disease is often familial and appears to be inherited as an autosomal recessive trait. SYN: familial erythrophagocytic l..

lymphoid (lim′foyd)
Resembling lymph or lymphatic tissue, or pertaining to the lymphatic system. [lympho- + G. eidos, appearance]

lymphoidectomy (lim-foy-dek′to-me)
Excision of lymphoid tissue. [lymphoid + G. ektome, excision]

lymphoidocyte (lim-foy′do-sit)
A primitive mesenchymal cell believed to be capable of differentiating into all types of lymphoid cells, including lymphocytes, littoral cells, and reticular cells of lymph nodes.

lymphokine (lim′fo-kinz)
Hormonelike peptide, released by activated lymphocytes, that mediates immune response; a cytokine obtained from lymphocytes. [lymphocyte + G. kineo, to set in motion]

lymphokinesis (lim′fo-ki-ne′sis)
1. Circulation of lymph in the lymphatic vessels and through the lymph nodes. 2. Movement of endolymph in the semicircular canals of the inner ear. SYN: lymphocinesis, lymphocinesia. [lympho- + G. kinesis, movement]

lympholeukocyte (lim′fo-loo′ko-sit)
SYN: lymphocyte.

lymphology (lim-fol′o-je)
SYN: lymphangiology. [lympho- + G. logos, study]

lymphoma (lim-fo′ma)
Any neoplasm of lymphoid tissue; in general use, synonymous with malignant l.. [lympho- + G. -oma, tumor] adult T-cell l. (ATL) an acute or subacute disease associated with a human T-cell virus, with lymphadenopathy, hepatosplenomegaly, skin lesions, peripheral blood involvement, and hypercalcemia. SYN: adult T-cell leukemia. anaplastic large cell l. a form of l. characterized by anaplasia of cells, sinusoidal growth, and immunoreactivity with CD30 (Ki-1 or Ber-H2). SYN: Ki-1+ l.. benign l. of the rectum obsolete term for a rectal polyp composed of lymphoid tissue with follicle formation, covered by mucosa. Burkitt l. a form of malignant l. reported in African children, frequently involving the jaw and abdominal lymph nodes. Geographic distribution of Burkitt l. suggests that it is found in areas with endemic malaria. It is primarily a B-cell neoplasm and is believed to be caused by Epstein-Barr virus, a member of the family Herpesviridae, which can be isolated from tumor cells in culture; occasional cases of l. with similar features have been reported in the United States. chronic lymphocytic l. a type of low-grade non-Hodgkin l. characterized by lymphocytosis, lymphadenoathy, and, in late stages, hepatosplenomegaly; may evolve into chronic lymphocytic leukemia over the course of several years. diffuse small cleaved cell l. diffuse poorly differentiated lymphocytic l.; follicular center cell l. that lacks a follicular pattern; malignancy is of intermediate grade. extranodal marginal zone l. SYN: MALToma. follicular l. SYN: nodular l.. follicular predominantly large cell l. a B-cell l. of intermediate malignancy. follicular predominantly small cleaved cell l. SYN: poorly differentiated lymphocytic l.. histiocytic l. a malignant tumor of reticular tissue composed predominantly of neoplastic histiocytes. SEE ALSO: large cell l.. Hodgkin l. SYN: Hodgkin disease. immunoblastic l. a monomorphous proliferation of immunoblasts involving the lymph nodes; it may develop in some patients with angioimmunoblastic lymphadenopathy. Ki-1+ l. SYN: anaplastic large cell l.. large cell l. l. composed of large mononuclear cells of undetermined type. Many lymphomas formerly classified as histiocytic have in recent years been shown to consist of large lymphocytes. Lennert l. malignant l. with a high proportion of diffusely scattered epithelioid cells, tonsillar involvement, and an unpredictable course. lymphoblastic l. a diffuse l. in children, with supradiaphragmatic distribution and T lymphocytes having convoluted nuclei; many patients develop acute lymphoblastic leukemia. SYN: lymphoblastoma. malignant l. general term for ordinarily malignant neoplasms of lymphoid and reticuloendothelial tissues which present as apparently circumscribed solid tumors composed of cells that appear primitive or resemble lymphocytes, plasma cells, or histiocytes. Lymphomas appear most frequently in lymph nodes, spleen, or other normal sites of lymphoreticular cells; when disseminated, Lymphomas, especially of the lymphocytic type, may invade the peripheral blood and manifest as leukemia. Lymphomas are classified by cell type, degrees of differentiation, and nodular or diffuse pattern; Hodgkin disease and Burkitt l. are special forms. mantle cell l. a clinically and biologically distinct B-cell neoplasm with a recurring acquired genetic abnormality, the t(11;14) translocation, and a heterogeneous histologic appearance that may lead to confusion with reactive or other neoplastic lymphoproliferative disorders. marginal zone l. a heterogeneous group of neoplasms originating from the B-cell–rich zones of the lymph nodes, spleen, or extranodal lymphoid tissue. Those tumors originating from mucosa-associated lymphoid tissue (MALT), most often in the stomach, intestines, salivary glands, and lungs, are called MALTomas. Mediterranean l. SYN: immunoproliferative small intestinal disease. nodular l. malignant l. arising from lymphoid follicular B cells which may be small or large, growing in a nodular pattern. SYN: follicular l., giant follicular lymphoblastoma. nodular histiocytic l. SYN: poorly differentiated lymphocytic l.. non-Hodgkin l. (NHL) a l. other than Hodgkin disease, classified by Rappaport into a nodular or diffuse tumor pattern and by cell type; a working or international formulation separates such lymphomas into low, intermediate, and high grade malignancy and into cytologic subtypes reflecting follicular center cell or other origin. peripheral T-cell l., unspecified a heterogeneous group of T-cell neoplasms expressing typical T-cell markers such as CD2, CD3, CD5, and either T-cell α/β or γ/δ receptors. poorly differentiated lymphocytic l. a B-cell l. with nodular or diffuse lymph node or bone marrow involvement by large lymphoid cells. SYN: follicular predominantly small cleaved cell l., nodular histiocytic l.. small lymphocytic l. SYN: well-differentiated lymphocytic l.. T-cell–rich, B-cell l. a B-cell l. in which more than 90% of the cells are of T-cell origin, masking the large cells that form the neoplastic B-cell component. SEE ALSO: adult T-cell l.. well-differentiated lymphocytic l. essentially the same disease as chronic lymphocytic leukemia, except that lymphocytes are not increased in the peripheral blood; lymph nodes are enlarged and other lymphoid tissue or bone marrow is infiltrated by small lymphocytes. SYN: small lymphocytic l..

lymphomatoid (lim-fo′ma-toyd)
Resembling a lymphoma.

lymphomatosis (lim′fo-ma-to′sis)
Any condition characterized by the occurrence of multiple, widely distributed sites of involvement with lymphoma.

lymphomatous (lim-fo′ma-tus)
Pertaining to or characterized by lymphoma.

lymphonodus
lymph node.

lymphopathia (lim-fo-path′e-a)
SYN: lymphopathy.

lymphopathy (lim-fop′a-the)
Any disease of the lymphatic vessels or lymph nodes. SYN: lymphopathia. [lympho- + G. pathos, suffering]

lymphopenia (lim-fo-pe′ne-a)
A reduction, relative or absolute, in the number of lymphocytes in the circulating blood. SYN: lymphocytic leukopenia, lymphocytopenia. [lympho- + G. penia, poverty]

lymphoplasmapheresis (lim′fo-plaz′ma-fe-re′sis)
Separation and removal of lymphocytes and plasma from the withdrawn blood, with the remainder of the blood retransfused into the donor. [lymphocyte + plasma + G. aphairesis, a withdrawal]

lymphopoiesis (lim-fo-poy-e′sis)
The formation of lymphatic tissue. [lympho- + G. poiesis, a making]

lymphopoietic (lim-fo-poy-et′ik)
Pertaining to or characterized by lymphopoiesis.

lymphoreticulosis (lim′fo-re-tik-u-lo′sis)
Proliferation of the reticuloendothelial cells (macrophages) of the lymph nodes. benign inoculation l. SYN: catscratch disease.

lymphorrhagia (lim-fo-ra′je-a)
SYN: lymphorrhea. [lympho- + G. rhegnymi, to burst forth]

lymphorrhea (lim-fo-re′a)
An escape of lymph onto the surface of the skin from ruptured, torn, or cut lymphatic vessels. SYN: lymphorrhagia. [lympho- + G. rhoia, a flow]

lymphorrhoid (lim′fo-royd)
A dilation of a lymph channel, resembling a hemorrhoid. [lymph + -rrhoid, tending to leak, on the analogy of hemorrhoid]

lymphoscintigraphy (lim′fo-sin-tig′ra-fe)
Scintillation scanning of lymphatics or lymph nodes following intralymphatic or subcutaneous injection of a radionuclide.

lymphosis (lim-fo′sis)
Obsolete term for lymphocytic leukemia.

lymphostasis (lim-fos′ta-sis)
Obstruction of the normal flow of lymph. [lympho- + G. stasis, a standing still]

lymphotaxis (lim-fo-tak′sis)
The exertion of an effect that attracts or repels lymphocytes. [lympho- + G. taxis, orderly arrangement]

lymphotoxicity (lim′fo-tok-sis′i-te)
Toxicity to lymphocytes.

lymphotoxin (lim′fo-tok-sin)
A lymphokine from T lymphocytes that lyses or damages many cell types.

lymphotrophy (lim-fot′ro-fe)
Nourishment of the tissues by lymph in parts devoid of blood vessels. [lympho- + G. trophe, nourishment]

lymphuria (lim-foo′re-a)
Discharge of lymph in the urine. [lympho- + G. ouron, urine]

Lynch
Henry T., 20th century U.S. oncologist. See L. syndrome.

lynestrenol (lin-es′tren-ol)
A progestational agent, used with mestranol as an oral contraceptive. SYN: ethinylestrenol.

lyo-
Dissolution. SEE ALSO: lyso-. [G. lyo, to loosen, dissolve]

lyoenzyme (li-o-en′zim)
1. Any enzyme existing in the cell in soluble form. 2. A soluble enzyme.

lyolysis (li-ol′i-sis)
Rarely used term for solvolysis.

Lyon
B. B. Vincent, U.S. physician, 1880–1953. See Meltzer-L. test.

Lyon
Mary F., English cytogeneticist, *1925. See L. hypothesis, lyonization.

lyonization (li′on-i-za′shun)
The normal phenomenon that wherever there are two or more haploid sets of X-linked genes in each cell all but one of the genes are inactivated apparently at random and have no phenotypic expression. L. is usual but not invariable for all loci. Its randomness explains the more variable espressivity of X-linked traits in women than in men. L. occurs in men with the Klinefelter (XXY) karyotype. SEE ALSO: gene dosage compensation. SYN: Lyon hypothesis, X-inactivation. [M. Lyon]

lyophil, lyophile (li′o-fil, -fil)
A substance that is lyophilic.

lyophilic (li-o-fil′ik)
1. In colloid chemistry, denoting a dispersed phase having a pronounced affinity for the dispersion medium; when the dispersed phase is l., the colloid is usually a reversible one. 2. Denoting a preference for the solvent. SYN: lyotropic. [lyo- + G. phileo, to love]

lyophilization (li-of′i-li-za′shun)
1. The process of isolating a solid substance from solution by freezing the solution and evaporating the ice under vacuum. 2. The process of imparting lyophilic properties to a substance. SYN: freeze-drying.




A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

. . . Feedback