Copy of `Dorland's Medical Dictionary`

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Dorland's Medical Dictionary Category: Health and Medicine > Medical Dictionary Date & country: 31/12/2010, USA Words: 39128

lymphatic leukemia
lymphoblastic leukemia leukemia associated with hyperplasia and overactivity of the lymphoid tissue; there are increased numbers of circulating malignant lymphocytes and lymphoblasts. See also acute lymphoblastic leukemia and chronic lymphocytic leukemia.

lymphatic nodule
lymph node. a small dense accumulation of lymphocytes in the cortex of a lymph node, the source of the cytogenic and defense functions of the tissue. Called also lymph or lymphatic follicle.

lymphatic plexus
an interconnecting network of lymph vessels that provides drainage of lymph in a one-way flow. An example is the lymphocapillary vessels, collecting vessels, and trunks.

lymphatic sinuses
irregular, tortuous spaces within lymphoid tissues through which lymph flows.

lymphatic system
the lymphatic vessels and lymphoid tissues considered collectively. See also circulatory system.

lymphatic trunks
the lymphatic vessels (right or left lumbar, intestinal, right or left bronchomediastinal, right or left subclavian, and right or left jugular trunks) that drain lymph from various regions of the body into the right lymphatic or thoracic duct.

lymphatic vessel
one of the vessels that collect lymph from the tissues and carry it to the bloodstream.

lymphaticostomy
(lim-fat″ĭ-kos´tә-me) surgical creation of a permanent opening into a lymphatic duct, usually the thoracic duct.

lymphatism
(lim´fә-tiz″әm) a morbid state due to excessive production or growth of lymphoid tissues, resulting in impaired development and lowered vitality. Called also status lymphaticus.

lymphatolysis
(lim″fә-tol´ә-sis) destruction of lymphoid tissue. adj., lymphatolyt´ic., adj.

lymphectasia
(lim″fek-ta´zhә) distention with lymph.

lymphedema
(lim″fә-de´mә) chronic swelling of a part due to accumulation of interstitial fluid (edema) after obstruction of lymphatic vessels or lymph nodes.

lymphedema praecox
(lim″fә-de´mә pre´koks) see primary lymphedema.

lymphedema tarda
(lim″fә-de´mә tahr´dә) see primary lymphedema.

lymphnoditis
(limf″no-di´tis) inflammation of a lymph node.

lymphoblast
(lim´fo-blast) a morphologically immature lymphocyte, once thought to represent an early stage in lymphocyte development but now known to be an activated lymphocyte that has been transformed in response to antigenic stimulation. adj., lymphoblas´tic., adj.

lymphoblastic
(lim″fo-blas´tik) pertaining to a lymphoblast; producing lymphocytes.

lymphoblastic lymphoma
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, which are cytologically similar to the lymphoblasts seen in acute lymphoblastic leukemia.

lymphoblastoma
(lim″fo-blas-to´mә) lymphoblastic lymphoma.

lymphoblastosis
(lim″fo-blas-to´sis) an excess of lymphoblasts in the blood, as seen in lymphoblastic leukemia.

Lymphocryptovirus
(lim″fo-krip´to-vi″rәs) a genus of herpesviruses that includes the Epstein-Barr virus and species affecting nonhuman primates.

lymphocytapheresis
(lim″fo-si″tә-fә-re´sis) the selective removal of lymphocytes from withdrawn blood, which is then retransfused into the donor.

lymphocyte
(lim´fo-sīt) any of the mononuclear nonphagocytic leukocytes found in the blood, lymph, and lymphoid tissues; they comprise the body's immunocytes and their precursors. They are divided into two classes, B lymphocytes and T lymphocytes, responsible respectively for humoral immunity and cellular immunity. Most are small l...

lymphocyte activation
stimulation of lymphocytes by specific antigen or nonspecific mitogens resulting in synthesis of RNA, protein, and DNA and production of lymphokines; it is followed by proliferation and differentiation of various effector cells and memory cells. Activation is accompanied by morphologic changes known as lymphocyte transformation, in w...

lymphocyte mitogenic factor
(LMF) lymphocyte-transforming factor a substance that is released by lymphocytes stimulated by specific antigen and causes nonstimulated lymphocytes to undergo blast transformation and cell division; called also blastogenic factor.

lymphocyte proliferation test
a functional test of the ability of lymphocytes to respond to mitogens, specific antigens, or allogeneic cells. The test with allogenic cells, called a mixed lymphocyte culture (MLC), is commonly performed for transplantation tissue typing; all three types of stimulants are used in investigation of immunodeficiency. Commonly used mit...

lymphocyte series
lymphocytic series the succession of developing cells that ultimately culminates in mature lymphocytes. The morphologically distinguishable forms are lymphoblast, prolymphocyte, and lymphocyte.

lymphocyte transforming factor
(LTF) a lymphokine causing transformation and clonal expansion of nonsensitized lymphocytes.

lymphocyte-associated virus
any virus of the subfamily Gammaherpesvirinae, which are specific for either B or T lymphocytes. Infection is often arrested before production of infectious virions, and latent virus may frequently be demonstrated in lymphoid tissue.

lymphocytic choriomeningitis virus
an arenavirus that is the etiologic agent of lymphocytic choriomeningitis. Called also LCM virus.

lymphocytic interstitial pneumonia
lymphocytic interstitial pneumonitislymphoid interstitial pneumonia an insidious, slowly progressive interstitial lung disease of unknown etiology, marked by diffuse peribronchial and interstitial infiltration of the lungs by lymphocytes, plasma cells, and lymphoblasts; usually seen in immunocompromised patients, especially ...

lymphocytic leukemia
lymphogenous leukemialymphoid leukemia lymphoblastic leukemia.

lymphocytoblast
(lim″fo-si´to-blast) lymphoblast.

lymphocytoma
(lim″fo-si-to´mә) pseudolymphoma. lymphocytoma cutis cutaneous lymphoid hyperplasia.

lymphocytopenia
(lim″fo-si″to-pe´ne-ә) reduction of the number of lymphocytes in the blood; called also lymphopenia.

lymphocytopheresis
(lim″fo-si″to-fә-re´sis) lymphocytapheresis.

lymphocytopoiesis
(lim″fo-si″to-poi-e´sis) the formation of lymphocytes. adj., lymphocytopoiet´ic., adj.

lymphocytosis
(lim″fo-si-to´sis) increase in the number of normal lymphocytes in the blood or in an effusion.

lymphocytotoxicity
(lim″fo-si″to-tok-sis´ĭ-te) the quality or capability of lysing lymphocytes, as in procedures in which lymphocytes having a specific cell surface antigen are lysed when incubated with antiserums and complement.

lymphogenous
(lim-foj´ә-nәs) producing lymph. produced from lymph or in the lymph vessels.

lymphogram
(lim´fo-gram) a radiograph of the lymphatic channels and lymph nodes.

lymphogranuloma
(lim″fo-gran″u-lo´mә) Hodgkin disease. old term for any of various granulomatous conditions involving lymph nodes. lymphogranuloma inguinale , lymphogranuloma venereum a sexually transmitted disease caused by a strain of Chlamydia trachomat...

lymphogranuloma venereum antigen
a sterile suspension of Chlamydia lymphogranulomatis; used as a dermal reactivity indicator.

lymphogranulomatosis
(lim″fo-gran″u-lo-mә-to´sis) European synonym for Hodgkin disease.

lymphography
(lim-fog´rә-fe) radiography of the lymphatic channels and lymph nodes after injection of radiopaque material in a lymphatic vessel.

lymphoid
(lim´foid) resembling or pertaining to lymph or to tissue of the lymphatic system.

lymphoid cells
lymphocytes and plasma cells.

lymphoid system
the lymphoid tissue of the body, collectively; it consists of primary (or central) lymphoid tissues, the bone marrow, and thymus, and secondary (or peripheral) tissues, the lymph nodes, spleen, and gut-associated lymphoid tissue (tonsils, Peyer patches).

lymphoid tissue
a latticework of reticular tissue whose interspaces contain lymphocytes.

lymphoidectomy
(lim″foi-dek´tә-me) excision of lymphoid tissue, such as tonsils and adenoids.

lymphokine
(lim´fo-kīn) any of various soluble protein mediators released by sensitized lymphocytes on contact with antigen, and believed to play a role in macrophage activation, lymphocyte transformation, and cell-mediated immunity. It regulates immune responses through differentiation, amplification, and inhibition of cell ...

lymphokine-activated killer cells
T lymphocytes that have been incubated with interleukin-2; used as a biological response modifier in the treatment of cancer. Called also LAK cells.

lymphokinesis
(lim″fo-kĭ-ne´sis) movement of endolymph in the semicircular canals. the circulation of lymph in the body.

lymphology
(lim-fol´ә-je) the study of the lymphatic system.

lympholytic
(lim″fo-lit´ik) causing destruction of lymphocytes.

lymphoma
(lim-fo´mә) any neoplastic disorder of lymphoid tissue; the term is often limited to the malignant lymphomas.

lymphoma cutis
(lim-fo´mә ku´tis) primary skin involvement by B-cell lymphoma without evident systemic disease; it usually consists of a lone, purple to pink nodule on the head, neck, or face, accompanied by spread to lymph nodes in the region and later to other sites via the bloodstream.

lymphomatoid granulomatosis
a multisystem disease involving predominantly the lungs, skin, central nervous system, and kidneys, caused by invasion and destruction of vessels by atypical lymphoreticular cells. Many affected patients develop frank lymphoma. It usually affects males, and the most frequent presenting symptoms are cough, shortness of bre...

lymphomatosis
(lim″fo-mә-to´sis) the formation of multiple malignant cell infiltrations of the lymphatic system.

lymphomatous
(lim-fo´mә-tәs) pertaining to, or of the nature of, lymphoma.

lymphopathy
(lim-fop´ә-the) any disease of the lymphatic system.

lymphopenia
(lim″fo-pe´ne-ә) lymphocytopenia.

lymphoplasmacytic lymphoma
lymphoplasmacytoid lymphoma a heterogeneous group of low-grade B-cell lymphomas characterized by a mixture of small lymphocytes and plasmacytoid lymphocytes; it is sometimes associated with Waldenström macroglobulinemia and can involve a number of tissues, including the lymph nodes, spleen, bone marrow, and gastrointestinal tract. Man...

lymphopoiesis
(lim″fo-poi-e´sis) the development of lymphocytes or of lymphoid tissue. adj., lymphopoiet´ic., adj.

lymphoproliferative
(lim″fo-pro-lif´әr-ә-tiv) pertaining to or characterized by proliferation of lymphoid tissue.

lymphoproliferative diseases
lymphoproliferative disorderslymphoproliferative syndromes a group of malignant neoplasms arising from cells related to the common multipotential, primordial lymphoreticular cell that includes among others the lymphocytic, histiocytic, and monocytic leukemias, multiple myeloma, plasmacytoma, Hodgkin disease, all types of lymphoc...

lymphoreticular
(lim″fo-rә-tik´u-lәr) pertaining to the reticuloendothelial cells of lymph nodes.

lymphoreticular diseases
lymphoreticular disorderslymphoreticular syndromes a group of disorders of the lymphoreticular system, characterized by the proliferation of lymphocytes or lymphoid tissues; they may be either benign (such as lymphocytosis) or malignant (such as lymphoblastic leukemias, multiple myeloma, or non-Hodgkin lymphomas). See also lymphoproli...

lymphoreticular system
the lymphoid and reticuloendothelial systems considered together; see also lymphoreticular disorders.

lymphoreticulosis
(lim″fo-rә-tik″u-lo´sis) proliferation of reticuloendothelial cells of the lymph nodes. benign lymphoreticulosis cat-scratch disease.

lymphorrhagia
(lim″fo-ra´jә) lymphorrhea.

lymphorrhea
(lim″fo-re´ә) flow of lymph from cut or ruptured lymphatic vessels.

lymphosarcoma
(lim″fo-sahr-ko´mә) a diffuse lymphoma.

lymphosarcoma cell leukemia
B-cell type acute lymphoblastic leukemia.

lymphoscintigraphy
(lim″fo-sin-tig´rә-fe) scintigraphic detection of metastatic tumors in radiolabeled lymph nodes, particularly that using radiolabeled colloid (radiocolloid lymphoscintigraphy). The colloid is taken up by macrophages in the lymph nodes, and the uptake in tumor-containing nodes is noticeably lower.

lymphostasis
(lim-fos´tә-sis) stoppage of lymph flow.

lymphotaxis
(lim″fo-tak´sis) the property of attracting or repulsing lymphocytes.

lymphotoxin
(lim´fo-tok″sin) a lymphokine that is one of the tumor necrosis factors, produced by activated T lymphocytes. It inhibits the growth of tumors by causing lysis or stasis of sensitive cells, and also blocks transformation of cells. Called also tumor necrosis factor β.

lymphotropic
(lim″fo-tro´pik) having an affinity for lymphatic tissue.

Lynch incision
the incision used in the Lynch operation, running midway between the medial canthus and nasion and extending into the inferior aspect of the brow.

Lynch operation
incision of the frontal sinus and removal of its floor and contents; done in cases of expanding mucoceles, pyoceles, and tumors of the sinus.

lyonization
(li″on-ĭ-za´shәn) 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.

lyophil
(li´o-fil) a lyophilic substance.

lyophile
(li´o-fīl) lyophil.

lyophilic
(li″o-fil´ik) having an affinity for, or stable in, solution.

lyophilic colloid
a stable colloid system in which the disperse phase is relatively liquid, usually comprising highly complex organic substances, such as glue or starch, which readily absorb solvent, swell, and distribute uniformly through the continuous phase.

lyophilization
(li-of″ĭ-lĭ-za´shәn) the creation of a stable preparation of a biologic substance by rapid freezing and dehydration of the frozen product under high vacuum. See also freeze-drying.

lyophobe
(li´o-fōb) a lyophobic substance.

lyophobic
(li″o-fo´bik) not having an affinity for, or unstable in, solution.

lyophobic colloid
an unstable colloid system in which the disperse phase particles tend to repel liquids, are easily precipitated, and cannot be redispersed with additional solvent.

lyotropic
(li″o-tro´pik) lyophilic.

lypressin
(li-pres´in) a synthetic preparation of lysine vasopressin, used as an antidiuretic and vasoconstrictor to treat central diabetes insipidus when desmopressin is too potent; administered by intranasal spray.

lyse
(līz) to cause or produce disintegration of a compound, substance, or cell. to undergo lysis.

lysergic acid diethylamide
LSD.

lysergide
(li-sur´jīd) LSD.

lysin
(li´sin) an antibody that causes complement-dependent lysis of cells; often used with a prefix indicating the target cells, as hemolysin or bacteriolysin. any substance that causes cell lysis.

lysine
(li´sēn) a naturally occurring essential amino acid that is necessary for optimal growth in infants and for maintenance of nitrogen equilibrium in adults. The acetate and hydrochloride salts are used for dietary supplements and the hydrochloride salt is used for the treatment of severe metabolic acidosis that is re...

lysinogen
(li-sin´ә-jәn) lysogen.

lysinuria
(li″sĭ-nu´re-ә) an aminoaciduria consisting of excessive lysine in the urine, such as in hyperlysinemia.

lysis
(li´sis) destruction, as of cells by a specific lysin. decomposition, as of a chemical compound by a specific agent. See also degradation. mobilization of an organ by division of restraining adhesions. the gradual abatement of the symptoms of a disease.