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Medical Dictionary


lipocatabolic (lip′o-kat-a-bol′ik)
Relating to the breakdown (catabolism) of fat.

lipoceratous (lip-o-ser′a-tus)
SYN: adipoceratous.

lipocere (lip′o-ser)
SYN: adipocere. [lipo- + L. cera, wax]

lipochondria (lip′o-kon′dre-a)
Temporary storage vacuoles of lipids found in the Golgi apparatus. SEE ALSO: phytosterolemia. [lipo- + mitochondria]

lipochondrodystrophy (lip′o-kon-dro-dis′tro-fe)
SYN: Hurler syndrome.

lipochrome (lip′o-krom)
1. A pigmented lipid, e.g., lutein, carotene. SYN: chromolipid. 2. A term sometimes used to designate the wear-and-tear pigments, e.g., lipofuscin, hemofuscin, ceroid. More precisely, lipochromes are yellow pigments that seem to be identical to carotene and xanthophyll and are frequently found in the serum, skin, adrenal cortex, corpus luteum, and arteriosclerotic plaques, as well as in the liver, spleen, and adipose tissue; lipochromes do not stain with the ordinary dyes for fat. 3. The pigment produced by certain bacteria. [lipo- + G. chroma, color]

lipoclasis (li-pok′la-sis)
SYN: lipolysis. [lipo- + G. klasis, a breaking]

lipoclastic (lip-o-klas′tik)
SYN: lipolytic.

lipocrit (lip′o-krit)
An apparatus and procedure for separating and volumetrically analyzing the amount of lipid in blood or other body fluid. [lipo- + G. krino, to separate]

lipocyte (lip′o-sit)
SYN: fat-storing cell. [lipo- + G. kytos, cell]

lipodermoid (lip-o-der′moyd)
Congenital, yellowish-white, fatty, benign tumor located subconjunctivally. [lipo- + dermoid]

lipodieresis (lip′o-di-er′e-sis)
SYN: lipolysis. [lipo- + G. diairesis, division]

lipodystrophia (lip′o-dis-tro′fe-a)
SYN: lipodystrophy. l. progessiva superior SYN: progressive lipodystrophy.

lipodystrophy (lip-o-dis′tro-fe)
Defective metabolism of fat. SYN: lipodystrophia. [lipo- + G. dys-, bad, difficult, + trophe, nourishment] congenital total l. [MIM*269700] characterized by almost complete lack of subcutaneous fat, accelerated rate of growth and skeletal development during the first 3–4 years of life, muscular hypertrophy, cardiac enlargement, hepatosplenomegaly, acanthosis nigricans, hypertrichosis, renal enlargement, hypertriglyceridemia, and hypermetabolism; autosomal recessive inheritance. SYN: Berardinelli syndrome, Seip syndrome. familial partial l. [MIM*151660] characterized by symmetric lipoatrophy of the trunk and limbs but the face is spared; with full rounded face, xanthomata, acanthosis nigricans, and insulin-resistant hyperglycemia; there is accumulation of fat around the neck and shoulders and genitalia. SYN: Kobberling-Dunnigan syndrome. insulin l. dystrophic atrophy of subcutaneous tissues in diabetics at the site of frequent injections of insulin. SYN: insulin lipoatrophy. membranous l. a rare metabolic disease in which bone marrow fat cells are transformed into thick convoluted PAS-staining membranes enclosing weakly osmophilic material; leads to progressive cystic resorption of limb bones and dementia with sudanophilic leukodystrophy. progressive l. a condition characterized by a complete loss of the subcutaneous fat of the upper part of the torso, the arms, neck, and face, sometimes with an increase of fat in the tissues about and below the pelvis. SYN: Barraquer disease, lipodystrophia progessiva superior, partial lipoatrophy, Simons disease.

lipoedema (lip′o-e-de′ma)
Edema of subcutaneous fat, causing painful swellings, especially of the legs in women. SYN: cellulite (2) .

lipofectin (lip′o-fek′tin)
A mixture predominantly of phospholipids used for aiding in the transfer of DNA into cells.

lipofection (lip′o-fek′shun)
The process of injecting a lipid-complexed or contained DNA into eucaryotic cells. [lipo- + transfection]

lipoferous (lip-of′er-us)
Transporting fat. [lipo- + L. fero, to carry]

lipofibroma (lip′o-fi-bro′ma)
A benign neoplasm of fibrous connective tissue, with conspicuous numbers of adipose cells.

lipofuscin (lip-o-fus′in)
Brown pigment granules representing lipid-containing residues of lysosomal digestion and considered one of the aging or “wear and tear” pigments; found in liver, kidney, heart muscle, adrenal, and ganglion cells.

lipofuscinosis (lip′o-fus-i-no′sis)
Abnormal storage of any one of a group of fatty pigments. ceroid l. SYN: Batten disease. neuronal ceroid l. a group of diseases characterized by accumulation of abnormal pigments in tissue (previously classified as cerebral sphingolipidoses). Major subtypes include chronic juvenile form (Batten disease), slowly progressive behavior and visual symptoms, autosomal recessive inheritance; acute, late infantile form (Bielschowsky disease); autosomal recessive inheritance; chronic adult form (Kufs disease), variable inheritance; acute infantile form (Santavuori-Haltia disease), fulminating motor and mental deterioration often associated with myoclonic seizures. Minor forms have also been described.

lipogenesis (lip-o-jen′e-sis)
The production of fat, either fatty degeneration or fatty infiltration; also applied to the normal deposition of fat or to the conversion of carbohydrate or protein to fat. SYN: adipogenesis. [lipo- + G. genesis, production]

lipogenic (lip-o-jen′ik)
Relating to lipogenesis. SYN: adipogenic, adipogenous, lipogenous.

lipogenous (li-poj′e-nus)
SYN: lipogenic.

lipogranuloma (lip′o-gran-u-lo′ma)
A nodule or focus of granulomatous inflammation (usually of the foreign-body type) in association with lipid material deposited in tissues, e.g., after the injection of certain oils. SEE ALSO: paraffinoma. SYN: eleoma, oil tumor, oleogranuloma, oleoma.

lipogranulomatosis (lip′o-gran′u-lo-ma-to′sis)
1. Presence of lipogranulomas. 2. Local inflammatory reaction to necrosis of adipose tissue. disseminated l. a form of mucolipodosis, developing soon after birth because of deficiency of ceramidase; characterized by swollen joints, subcutaneous nodules, lymphadenopathy, and accumulation in lysosomes of affected cells of PAS-positive lipid consisting of ceramide. SYN: Farber disease, Farber syndrome.

lipohemia (lip-o-he′me-a)
Obsolete term for lipemia.

lipoic acid (li-po′ik)
Functions as the amide (lipoamide) in the disulfide (–S–S–) form in the transfer of “active aldehyde” (acetyl), the two-carbon fragment resulting from decarboxylation of pyruvate from α-hydroxyethylthiamin pyrophosphate to acetyl-CoA, itself being reduced to the dithiol form ( i.e., dihydrolipoic acid) in the process; present in yeast and liver extracts, and may be useful in the treatment of mushroom poisoning. L. is also an essential component of other α-keto acid dehydrogenase complexes. SYN: acetate replacement factor, ovoprotogen, protogen, protogen A, pyruvate oxidation factor, thioctic acid.

lipoid (lip′oyd)
1. Resembling fat. 2. Former term for lipid. SYN: adipoid. [lipo- + G. eidos, appearance]

lipoidemia (lip-oy-de′me-a)
SYN: lipemia.

lipoidosis (lip-oy-do′sis)
Presence of anisotropic lipoids in the cells. cerebroside l. (ser-e′bro-sid) a group of lysosomal storage diseases characterized by accumulation of lipid in cells of affected tissue and commonly accompanied by a manifest derangement of central nervous system development; e.g., Gaucher disease and Krabbe disease. l. corneae SYN: arcus senilis. l. cutis et mucosae SYN: lipoid proteinosis. galactosylceramide l. SYN: globoid cell leukodystrophy.

lipoinjection (lip-o-in-jek′shun)
Augmentation of tissue with fat cells after atrophy, as in vocal cord paralysis or scarring.

lipolipoidosis (lip′o-lip-oy-do′sis)
Fatty infiltration, both neutral fats and anisotropic lipoids being present in the cells. SEE ALSO: liposis (2) .

lipolysis (li-pol′i-sis)
The splitting up (hydrolysis), or chemical decomposition, of fat. SYN: lipoclasis, lipodieresis. [lipo- + G. lysis, dissolution]

lipolytic (lip-o-lit′ik)
Relating to or causing lipolysis. SYN: lipoclastic.

lipoma (li-po′ma)
A benign neoplasm of adipose tissue, composed of mature fat cells. SYN: adipose tumor. [lipo- + G. -oma, tumor] l. annulare colli an encircling growth of l. (or coalescent lipomas) in the neck, resulting in a collar-like enlargement. SEE ALSO: Madelung neck. l. arborescens an irregularly shaped l. involving the synovial membrane of a joint, resulting in fingerlike or treelike hyperplastic folds in the villi. atypical l. l., occurring primarily in older men on the posterior neck, shoulders, and back, which is benign but microscopically atypical, containing giant cells with multiple overlapping nuclei forming a circle. SYN: pleomorphic l.. l. capsulare a well-circumscribed mass resulting from a greatly increased amount of adipose tissue adjacent to the breast. l. cavernosum SYN: angiolipoma. l. fibrosum SYN: fibrolipoma. l. myxomatodes SYN: myxolipoma. l. ossificans a l. in which metaplasia occurs and small foci of bone are formed. l. petrificans a l. in which degeneration and necrosis results in a considerable amount of dystrophic calcification. pleomorphic l. SYN: atypical l.. spindle cell l. a microscopically distinctive benign form of l. in which adipose tissue is infiltrated by fibroblasts and collagen; usually found in the shoulder or neck of elderly men. telangiectatic l. SYN: angiolipoma.

lipomatoid (li-po′ma-toyd)
Resembling a lipoma, frequently said of accumulations of adipose tissue that is not thought to be neoplastic.

lipomatosis (lip′o-ma-to′sis)
SYN: adiposis. encephalocraniocutaneous l. a rare syndrome of multiple fibrolipomas or angiofibromas of the face, scalp, and neck present at birth, sometimes with symptomatic intracranial lipomas. mediastinal l. increased mediastinal fat caused by taking steroids. multiple symmetric l. accumulation and progressive enlargement of collections of adipose tissue in the subcutaneous tissue of the head, neck, upper trunk, and upper portions of the upper extremities; seen primarily in adult males and of unknown cause. SYN: Launois-Bensaude syndrome, Madelung disease, symmetric adenolipomatosis. l. neurotica SYN: adiposis dolorosa.

lipomatous (li-po′ma-tus)
Pertaining to or manifesting the features of lipoma, or characterized by the presence of a lipoma (or lipomas).

lipomeningocele (lip′o-me-ning′go-sel)
An intraspinal cauda equinal lipoma associated with a spina bifida. [lipo- + G. meninx, membrane, + kele, tumor]

lipomucopolysaccharidosis (lip′o-mu′ko-pol-e-sak′a-ri-do′sis)
SYN: mucolipidosis I.

liponucleoproteins (lip′o-noo′kle-o-pro′tenz)
Associations or complexes containing lipids, nucleic acids, and proteins.

Liponyssus (lip-o-nis′us)
Former name for Ornithonyssus. [lipo- + G. nysso, to prick]

lipopenia (lip-o-pe′ne-a)
An abnormally small amount, or a deficiency, of lipids in the body. [lipo- + G. penia, poverty]

lipopenic (lip-o-pe′nik)
1. Relating to or characterized by lipopenia. 2. An agent or drug that produces a reduction in the concentration of lipids in the blood.

lipopeptid, lipopeptide (lip-o-pep′tid, lip-o-pep′tid)
A compound or complex of lipid and amino acids.

lipophage (lip′o-faj)
A cell that ingests fat. [G. lipos, fat, + phago, to eat]

lipophagic (lip-o-fa′jik)
Relating to lipophagy.

lipophagy (lip-of′a-je)
Ingestion of fat by a lipophage. [lipo- + G. phago, to eat]

lipophanerosis (lip′o-fan-er-o′sis)
A change in certain cells whereby previously invisible fat becomes demonstrable as small sudanophilic droplets. See fatty degeneration. [lipo- + G. phaneros, visible, + -osis, condition]

lipophil (lip′o-fil)
A substance with lipophilic (hydrophobic) properties. [lipo- + G. philos, fond of]

lipophilic (lip-o-fil′ik)
Capable of dissolving, of being dissolved in, or of absorbing lipids.

lipophosphodiesterase I (lip′o-fos′-fo-di-es′ter-as)
SYN: phospholipase C.

lipophosphodiesterase II
SYN: phospholipase D.

lipopolysaccharide (LPS) (lip′o-pol′e-sak′a-rid)
1. A compound or complex of lipid and carbohydrate. 2. The l. (endotoxin) released from the cell walls of Gram-negative organisms that produces septic shock.

lipoprotein (lip-o-pro′ten, li-po-)
Any complex or compound containing both lipid and protein. Lipoproteins are important constituents of biological membranes and of myelin. Conjugation with protein facilitates transport of lipids, which are hydrophobic, in the aqueous medium of the plasma. Plasma lipoproteins can be separated by ultracentrifugation, electrophoresis, or immunoelectrophoresis; they migrate electrophoretically with α- and β-globulins, but are usually classified according to their densities (flotation constants). The principal classes by density are chylomicrons, which transport dietary cholesterol and triglycerides from the intestine to the liver and other tissues; very low density lipoproteins (VLDL), which transport triglycerides from intestine and liver to muscle and adipose tissue; low density lipoproteins (LDL), which transport cholesterol to tissues other than the liver; and high density lipoproteins (HDL), which transport cholesterol to the liver for excretion in bile. The properties of these and other plasma lipoproteins are set forth in the accompanying table. The protein moiety of a l. is called an apolipoprotein (or apoprotein). Besides rendering lipids soluble, some apolipoproteins perform biochemical functions such as enzyme activation. The apolipoproteins of plasma lipoproteins are synthesized by the liver and intestinal mucosal cells and vary in molecular weight from 7000 to 500,000. Protein makes up more than 50% of some HDLs but only 1% of chylomicrons. As the proportion of lipid in a l. increases, its density decreases. A plasma l. particle is typically spherical, with a hydrophobic core of triacylglycerol, cholesteryl esters, and apolar amino acid residues surrounded by hydrophilic protein structures and phospholipids.The concentrations of certain serum lipoproteins correlate closely with the risk of atherosclerosis. An HDL cholesterol level below 35 mg/dL (0.90 mmol/L), an LDL cholesterol level above 160 mg/dL (4.15 mmol/L), and a fasting triglyceride level above 250 mg/dL are all independent risk factors for coronary artery disease. Although dietary factors are important in some persons, basal levels of l., cholesterol, and triglycerides depend chiefly on heredity. Several phenotypes of familial hyperlipoproteinemia associated with risk of premature cardiovascular disease and death have been identified. see hyperlipoproteinemia. Medical management of patients with coronary artery disease (myocardial infarction, angina pectoris, history of coronary artery bypass graft or coronary angioplasty) and other atherosclerotic disorders (peripheral arterial disease, abdominal aortic aneurysm, carotid artery disease) includes detection and correction of hypercholesterolemia and hyperlipoproteinemia. Reducing elevated LDL cholesterol diminishes the risk of coronary artery disease; besides halting the progression of atherosclerosis, it may even shrink established atherosclerotic lesions. Of persons with elevated LDL cholesterol, 75% can achieve normal levels with diet, weight reduction, and exercise; the remainder need drug treatment. Factors besides familial hyperlipoproteinemias that can elevate LDL cholesterol include diabetes mellitus, hypothyroidism, nephrotic syndrome, obstructive liver disease, and drugs (progestogens, anabolic steroids, corticosteroids, thiazide diuretics). Dietary saturated fat raises LDL cholesterol more than any other dietary component, cholesterol itself not excepted. l. (a) a l. consisting of an LDL particle to which a large glycoprotein, apolipoprotein (a), is covalently bonded. Elevation of the concentration in serum has been identified as a risk factor for coronary artery disease.Elevation of plasma l. (a) above 30 mg/dL is a strong independent risk factor for coronary artery disease and possibly for stroke. A unique feature of l. (a) is the structural similarity of its nonlipid moiety, apolipoprotein (a), to plasminogen. This similarity allows it to bind to endothelium and to proteins of cellular membranes. It inhibits fibrinolysis by competing for plasminogen binding sites and also favors lipid deposition and stimulates smooth muscle cell proliferation. Niacin and estrogen lower Lp(a), but HMG-CoA reductase inhibitors, fibrates, and bile acid sequestrants do not. α1-l. A l. fraction of relatively low molecular weight, high density, rich in phospholipids, and found in the α1-globulin fraction of human plasma. β1-l. A l. fraction of relatively high molecular weight, low density, rich in cholesterol, and found in the β-globulin fraction of human plasma. intermediate density l. (IDL) class of lipoproteins formed in degradation of very low density lipoproteins; about half are cleared quickly from the plasma into the liver by receptor-mediated endocytosis; the other half are degraded into low density lipoproteins. l. Lp(a) a l. composed of an LDL particle combined with an additional protein, Lp(a) specific protein; elevated levels have been identified as a risk factor for coronary artery disease; elevations may be treated with niacin. malondialdehyde-modified low-density l. lDL molecule with aldehyde-substituted lysine residue(s) in the apoprotein moiety, resulting from oxidative reaction accompanying prostaglandin synthesis and platelet aggregation. l.-X An abnormal low-density l. found in patients with obstructive jaundice.

lipoprotein lipase
An enzyme that hydrolyzes one fatty acid from a triacylglycerol; its activity is enhanced by heparin and inactivated by heparinase. It is activated by apolipoprotein C-II; a deficiency of l. is associated with familial hyperlipoproteinemia type I. SEE ALSO: familial l. inhibitor, clearing factors, under factor. SYN: diacylglycerol lipase, diglyceride lipase.

liposarcoma (lip′o-sar-ko′ma)
A malignant neoplasm of adults that occurs especially in the retroperitoneal tissues and the thigh, usually deep in the intermuscular or periarticular planes; histologically, l. is a large tumor that may be composed of well-differentiated fat cells or may be dedifferentiated, either myxoid, round-celled, or pleomorphic, usually in association with a rich network of capillaries; recurrences are common, and dedifferentiated l. metastasizes to the lungs or serosal surfaces. [lipo- + sarx, flesh, + -oma, tumor]

liposis (li-po′sis)
1. SYN: adiposis. 2. Fatty infiltration, neutral fats being present in the cells. SEE ALSO: lipolipoidosis. [lipo- + G. -osis, condition]

lipositol (lip-os′i-tol)
SYN: inositol.

liposoluble (lip-o-sol′u-bl)

liposome (lip′o-som)
1. A spherical particle of lipid substance suspended in an aqueous medium within a tissue. 2. Any small, roughly spherical artificial vesicle consisting of a lipid bilayer enclosing some of the suspending medium. [lipo- + G. soma, body]

liposuction (lip′o-suk-shun)
Method of removing unwanted subcutaneous fat using percutaneously placed suction tubes. tumescent l. l. performed after subcutaneous infusion of lidocaine solution and the use of microcannulae. wet-technique l. l. performed after subcutaneous infusion of dilute epinephrine solution.

liposuctioning (lip′o-suk′shun-ing)
Removal of fat by high vacuum pressure; used in body contouring.

lipothiamide pyrophosphate (lip-o-thi′am-id)
Name once given to the coenzymes of the multienzyme complex catalyzing the formation of acetyl-CoA from pyruvate and involving lipoamide and thiamin pyrophosphate, on the assumption that they were a single compound. See lipoic acid.

lipotrophic (lip-o-trof′ik)
Relating to lipotrophy.

lipotrophy (li-pot′ro-fe)
An increase of fat in the body. [lipo- + G. trophe, nourishment]


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