Apolipoproteins: Protein components on the surface of LIPOPROTEINS. They form a layer surrounding the hydrophobic lipid core. There are several classes of apolipoproteins with each playing a different role in lipid transport and LIPID METABOLISM. These proteins are synthesized mainly in the LIVER and the INTESTINES.Apolipoproteins A: Structural proteins of the alpha-lipoproteins (HIGH DENSITY LIPOPROTEINS), including APOLIPOPROTEIN A-I and APOLIPOPROTEIN A-II. They can modulate the activity of LECITHIN CHOLESTEROL ACYLTRANSFERASE. These apolipoproteins are low in atherosclerotic patients. They are either absent or present in extremely low plasma concentration in TANGIER DISEASE.Apolipoproteins C: A group of apolipoproteins that can readily exchange among the various classes of lipoproteins (HDL; VLDL; CHYLOMICRONS). After lipolysis of TRIGLYCERIDES on VLDL and chylomicrons, Apo-C proteins are normally transferred to HDL. The subtypes can modulate remnant binding to receptors, LECITHIN CHOLESTEROL ACYLTRANSFERASE, or LIPOPROTEIN LIPASE.Apolipoproteins B: Major structural proteins of triacylglycerol-rich LIPOPROTEINS. There are two forms, apolipoprotein B-100 and apolipoprotein B-48, both derived from a single gene. ApoB-100 expressed in the liver is found in low-density lipoproteins (LIPOPROTEINS, LDL; LIPOPROTEINS, VLDL). ApoB-48 expressed in the intestine is found in CHYLOMICRONS. They are important in the biosynthesis, transport, and metabolism of triacylglycerol-rich lipoproteins. Plasma Apo-B levels are high in atherosclerotic patients but non-detectable in ABETALIPOPROTEINEMIA.Apolipoprotein A-I: The most abundant protein component of HIGH DENSITY LIPOPROTEINS or HDL. This protein serves as an acceptor for CHOLESTEROL released from cells thus promoting efflux of cholesterol to HDL then to the LIVER for excretion from the body (reverse cholesterol transport). It also acts as a cofactor for LECITHIN CHOLESTEROL ACYLTRANSFERASE that forms CHOLESTEROL ESTERS on the HDL particles. Mutations of this gene APOA1 cause HDL deficiency, such as in FAMILIAL ALPHA LIPOPROTEIN DEFICIENCY DISEASE and in some patients with TANGIER DISEASE.Apolipoprotein A-II: The second most abundant protein component of HIGH DENSITY LIPOPROTEINS or HDL. It has a high lipid affinity and is known to displace APOLIPOPROTEIN A-I from HDL particles and generates a stable HDL complex. ApoA-II can modulate the activation of LECITHIN CHOLESTEROL ACYLTRANSFERASE in the presence of APOLIPOPROTEIN A-I, thus affecting HDL metabolism.Apolipoproteins E: A class of protein components which can be found in several lipoproteins including HIGH-DENSITY LIPOPROTEINS; VERY-LOW-DENSITY LIPOPROTEINS; and CHYLOMICRONS. Synthesized in most organs, Apo E is important in the global transport of lipids and cholesterol throughout the body. Apo E is also a ligand for LDL receptors (RECEPTORS, LDL) that mediates the binding, internalization, and catabolism of lipoprotein particles in cells. There are several allelic isoforms (such as E2, E3, and E4). Deficiency or defects in Apo E are causes of HYPERLIPOPROTEINEMIA TYPE III.Apolipoprotein C-II: A 9-kDa protein component of VERY-LOW-DENSITY LIPOPROTEINS. It contains a cofactor for LIPOPROTEIN LIPASE and activates several triacylglycerol lipases. The association of Apo C-II with plasma CHYLOMICRONS; VLDL, and HIGH-DENSITY LIPOPROTEINS is reversible and changes rapidly as a function of triglyceride metabolism. Clinically, Apo C-II deficiency is similar to lipoprotein lipase deficiency (HYPERLIPOPROTEINEMIA TYPE I) and is therefore called hyperlipoproteinemia type IB.Apolipoprotein C-III: A 9-kDa protein component of VERY-LOW-DENSITY LIPOPROTEINS and CHYLOMICRON REMNANTS. Apo C-III, synthesized in the liver, is an inhibitor of LIPOPROTEIN LIPASE. Apo C-III modulates the binding of chylomicron remnants and VLDL to receptors (RECEPTORS, LDL) thus decreases the uptake of triglyceride-rich particles by the liver cells and subsequent degradation. The normal Apo C-III is glycosylated. There are several polymorphic forms with varying amounts of SIALIC ACID (Apo C-III-0, Apo C-III-1, and Apo C-III-2).Lipoproteins, HDL: A class of lipoproteins of small size (4-13 nm) and dense (greater than 1.063 g/ml) particles. HDL lipoproteins, synthesized in the liver without a lipid core, accumulate cholesterol esters from peripheral tissues and transport them to the liver for re-utilization or elimination from the body (the reverse cholesterol transport). Their major protein component is APOLIPOPROTEIN A-I. HDL also shuttle APOLIPOPROTEINS C and APOLIPOPROTEINS E to and from triglyceride-rich lipoproteins during their catabolism. HDL plasma level has been inversely correlated with the risk of cardiovascular diseases.Apolipoproteins D: A glycoprotein component of HIGH-DENSITY LIPOPROTEINS that transports small hydrophobic ligands including CHOLESTEROL and STEROLS. It occurs in the macromolecular complex with LECITHIN CHOLESTEROL ACYLTRANSFERASE. Apo D is expressed in and secreted from a variety of tissues such as liver, placenta, brain tissue and others.Lipoproteins: Lipid-protein complexes involved in the transportation and metabolism of lipids in the body. They are spherical particles consisting of a hydrophobic core of TRIGLYCERIDES and CHOLESTEROL ESTERS surrounded by a layer of hydrophilic free CHOLESTEROL; PHOSPHOLIPIDS; and APOLIPOPROTEINS. Lipoproteins are classified by their varying buoyant density and sizes.Apolipoprotein C-I: A 6.6-kDa protein component of VERY-LOW-DENSITY LIPOPROTEINS; INTERMEDIATE-DENSITY LIPOPROTEINS; and HIGH-DENSITY LIPOPROTEINS. Apo C-I displaces APO E from lipoproteins, modulate their binding to receptors (RECEPTORS, LDL), and thereby decrease their clearance from plasma. Elevated Apo C-I levels are associated with HYPERLIPOPROTEINEMIA and ATHEROSCLEROSIS.Cholesterol: The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.Lipoproteins, VLDL: A class of lipoproteins of very light (0.93-1.006 g/ml) large size (30-80 nm) particles with a core composed mainly of TRIGLYCERIDES and a surface monolayer of PHOSPHOLIPIDS and CHOLESTEROL into which are imbedded the apolipoproteins B, E, and C. VLDL facilitates the transport of endogenously made triglycerides to extrahepatic tissues. As triglycerides and Apo C are removed, VLDL is converted to INTERMEDIATE-DENSITY LIPOPROTEINS, then to LOW-DENSITY LIPOPROTEINS from which cholesterol is delivered to the extrahepatic tissues.TriglyceridesLipids: A generic term for fats and lipoids, the alcohol-ether-soluble constituents of protoplasm, which are insoluble in water. They comprise the fats, fatty oils, essential oils, waxes, phospholipids, glycolipids, sulfolipids, aminolipids, chromolipids (lipochromes), and fatty acids. (Grant & Hackh's Chemical Dictionary, 5th ed)Apolipoprotein B-100: A 513-kDa protein synthesized in the LIVER. It serves as the major structural protein of low-density lipoproteins (LIPOPROTEINS, LDL; LIPOPROTEINS, VLDL). It is the ligand for the LDL receptor (RECEPTORS, LDL) that promotes cellular binding and internalization of LDL particles.Apolipoprotein B-48: A 241-kDa protein synthesized only in the INTESTINES. It serves as a structural protein of CHYLOMICRONS. Its exclusive association with chylomicron particles provides an indicator of intestinally derived lipoproteins in circulation. Apo B-48 is a shortened form of apo B-100 and lacks the LDL-receptor region.Cholesterol, HDL: Cholesterol which is contained in or bound to high-density lipoproteins (HDL), including CHOLESTEROL ESTERS and free cholesterol.Lipoproteins, HDL3: Intermediate-density subclass of the high-density lipoproteins, with particle sizes between 7 to 8 nm. As the larger lighter HDL2 lipoprotein, HDL3 lipoprotein is lipid-rich.Tangier Disease: An autosomal recessively inherited disorder caused by mutation of ATP-BINDING CASSETTE TRANSPORTERS involved in cellular cholesterol removal (reverse-cholesterol transport). It is characterized by near absence of ALPHA-LIPOPROTEINS (high-density lipoproteins) in blood. The massive tissue deposition of cholesterol esters results in HEPATOMEGALY; SPLENOMEGALY; RETINITIS PIGMENTOSA; large orange tonsils; and often sensory POLYNEUROPATHY. The disorder was first found among inhabitants of Tangier Island in the Chesapeake Bay, MD.Phosphatidylcholine-Sterol O-Acyltransferase: An enzyme secreted from the liver into the plasma of many mammalian species. It catalyzes the esterification of the hydroxyl group of lipoprotein cholesterol by the transfer of a fatty acid from the C-2 position of lecithin. In familial lecithin:cholesterol acyltransferase deficiency disease, the absence of the enzyme results in an excess of unesterified cholesterol in plasma. EC 2.3.1.43.Lipoproteins, LDL: A class of lipoproteins of small size (18-25 nm) and light (1.019-1.063 g/ml) particles with a core composed mainly of CHOLESTEROL ESTERS and smaller amounts of TRIGLYCERIDES. The surface monolayer consists mostly of PHOSPHOLIPIDS, a single copy of APOLIPOPROTEIN B-100, and free cholesterol molecules. The main LDL function is to transport cholesterol and cholesterol esters to extrahepatic tissues.Nephelometry and Turbidimetry: Chemical analysis based on the phenomenon whereby light, passing through a medium with dispersed particles of a different refractive index from that of the medium, is attenuated in intensity by scattering. In turbidimetry, the intensity of light transmitted through the medium, the unscattered light, is measured. In nephelometry, the intensity of the scattered light is measured, usually, but not necessarily, at right angles to the incident light beam.ATP Binding Cassette Transporter 1: A superfamily of large integral ATP-binding cassette membrane proteins whose expression pattern is consistent with a role in lipid (cholesterol) efflux. It is implicated in TANGIER DISEASE characterized by accumulation of cholesteryl ester in various tissues.Cholesterol Esters: Fatty acid esters of cholesterol which constitute about two-thirds of the cholesterol in the plasma. The accumulation of cholesterol esters in the arterial intima is a characteristic feature of atherosclerosis.Isoelectric Focusing: Electrophoresis in which a pH gradient is established in a gel medium and proteins migrate until they reach the site (or focus) at which the pH is equal to their isoelectric point.Receptors, Lipoprotein: Cell surface proteins that bind lipoproteins with high affinity. Lipoprotein receptors in the liver and peripheral tissues mediate the regulation of plasma and cellular cholesterol metabolism and concentration. The receptors generally recognize the apolipoproteins of the lipoprotein complex, and binding is often a trigger for endocytosis.Lipid Metabolism: Physiological processes in biosynthesis (anabolism) and degradation (catabolism) of LIPIDS.Chylomicrons: A class of lipoproteins that carry dietary CHOLESTEROL and TRIGLYCERIDES from the SMALL INTESTINE to the tissues. Their density (0.93-1.006 g/ml) is the same as that of VERY-LOW-DENSITY LIPOPROTEINS.Cholesterol, LDL: Cholesterol which is contained in or bound to low density lipoproteins (LDL), including CHOLESTEROL ESTERS and free cholesterol.Phospholipids: Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.Ultracentrifugation: Centrifugation with a centrifuge that develops centrifugal fields of more than 100,000 times gravity. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Hypolipoproteinemias: Conditions with abnormally low levels of LIPOPROTEINS in the blood. This may involve any of the lipoprotein subclasses, including ALPHA-LIPOPROTEINS (high-density lipoproteins); BETA-LIPOPROTEINS (low-density lipoproteins); and PREBETA-LIPOPROTEINS (very-low-density lipoproteins).Lipoproteins, HDL2: Low-density subclass of the high-density lipoproteins, with particle sizes between 8 to 13 nm.Lipoprotein(a): A lipoprotein that resembles the LOW-DENSITY LIPOPROTEINS but with an extra protein moiety, APOPROTEIN (A) also known as APOLIPOPROTEIN (A), linked to APOLIPOPROTEIN B-100 on the LDL by one or two disulfide bonds. High plasma level of lipoprotein (a) is associated with increased risk of atherosclerotic cardiovascular disease.Lymph: The interstitial fluid that is in the LYMPHATIC SYSTEM.Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Apoproteins: The protein components of a number of complexes, such as enzymes (APOENZYMES), ferritin (APOFERRITINS), or lipoproteins (APOLIPOPROTEINS).Hyperlipidemias: Conditions with excess LIPIDS in the blood.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Immunodiffusion: Technique involving the diffusion of antigen or antibody through a semisolid medium, usually agar or agarose gel, with the result being a precipitin reaction.Lipoprotein Lipase: An enzyme of the hydrolase class that catalyzes the reaction of triacylglycerol and water to yield diacylglycerol and a fatty acid anion. The enzyme hydrolyzes triacylglycerols in chylomicrons, very-low-density lipoproteins, low-density lipoproteins, and diacylglycerols. It occurs on capillary endothelial surfaces, especially in mammary, muscle, and adipose tissue. Genetic deficiency of the enzyme causes familial hyperlipoproteinemia Type I. (Dorland, 27th ed) EC 3.1.1.34.Triolein: (Z)-9-Octadecenoic acid 1,2,3-propanetriyl ester.Hyperlipoproteinemia Type IV: A hypertriglyceridemia disorder, often with autosomal dominant inheritance. It is characterized by the persistent elevations of plasma TRIGLYCERIDES, endogenously synthesized and contained predominantly in VERY-LOW-DENSITY LIPOPROTEINS (pre-beta lipoproteins). In contrast, the plasma CHOLESTEROL and PHOSPHOLIPIDS usually remain within normal limits.Phosphatidylcholines: Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to a choline moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and choline and 2 moles of fatty acids.Kinetics: The rate dynamics in chemical or physical systems.ATP-Binding Cassette Transporters: A family of MEMBRANE TRANSPORT PROTEINS that require ATP hydrolysis for the transport of substrates across membranes. The protein family derives its name from the ATP-binding domain found on the protein.Hyperlipoproteinemias: Conditions with abnormally elevated levels of LIPOPROTEINS in the blood. They may be inherited, acquired, primary, or secondary. Hyperlipoproteinemias are classified according to the pattern of lipoproteins on electrophoresis or ultracentrifugation.Apolipoprotein E3: A 34-kDa glycosylated protein. A major and most common isoform of apolipoprotein E. Therefore, it is also known as apolipoprotein E (ApoE). In human, Apo E3 is a 299-amino acid protein with a cysteine at the 112 and an arginine at the 158 position. It is involved with the transport of TRIGLYCERIDES; PHOSPHOLIPIDS; CHOLESTEROL; and CHOLESTERYL ESTERS in and out of the cells.Chemistry, Clinical: The specialty of ANALYTIC CHEMISTRY applied to assays of physiologically important substances found in blood, urine, tissues, and other biological fluids for the purpose of aiding the physician in making a diagnosis or following therapy.Cholesterol, VLDL: Cholesterol which is contained in or bound to very low density lipoproteins (VLDL). High circulating levels of VLDL cholesterol are found in HYPERLIPOPROTEINEMIA TYPE IIB. The cholesterol on the VLDL is eventually delivered by LOW-DENSITY LIPOPROTEINS to the tissues after the catabolism of VLDL to INTERMEDIATE-DENSITY LIPOPROTEINS, then to LDL.Hypertriglyceridemia: A condition of elevated levels of TRIGLYCERIDES in the blood.Cholesterol Ester Transfer Proteins: Proteins that bind to and transfer CHOLESTEROL ESTERS between LIPOPROTEINS such as LOW-DENSITY LIPOPROTEINS and HIGH-DENSITY LIPOPROTEINS.Lipoproteins, IDL: A mixture of very-low-density lipoproteins (VLDL), particularly the triglyceride-poor VLDL, with slow diffuse electrophoretic mobilities in the beta and alpha2 regions which are similar to that of beta-lipoproteins (LDL) or alpha-lipoproteins (HDL). They can be intermediate (remnant) lipoproteins in the de-lipidation process, or remnants of mutant CHYLOMICRONS and VERY-LOW-DENSITY LIPOPROTEINS which cannot be metabolized completely as seen in FAMILIAL DYSBETALIPOPROTEINEMIA.Reference Values: The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.Scavenger Receptors, Class B: A family of scavenger receptors that are predominately localized to CAVEOLAE of the PLASMA MEMBRANE and bind HIGH DENSITY LIPOPROTEINS.Freeze Drying: Method of tissue preparation in which the tissue specimen is frozen and then dehydrated at low temperature in a high vacuum. This method is also used for dehydrating pharmaceutical and food products.Ethinyl Estradiol: A semisynthetic alkylated ESTRADIOL with a 17-alpha-ethinyl substitution. It has high estrogenic potency when administered orally, and is often used as the estrogenic component in ORAL CONTRACEPTIVES.Particle Size: Relating to the size of solids.Immunoassay: A technique using antibodies for identifying or quantifying a substance. Usually the substance being studied serves as antigen both in antibody production and in measurement of antibody by the test substance.Serum Amyloid A Protein: An ACUTE PHASE REACTION protein present in low concentrations in normal sera, but found at higher concentrations in sera of older persons and in patients with AMYLOIDOSIS. It is the circulating precusor of amyloid A protein, which is found deposited in AA type AMYLOID FIBRILS.Dietary Fats: Fats present in food, especially in animal products such as meat, meat products, butter, ghee. They are present in lower amounts in nuts, seeds, and avocados.Microscopy, Electron: Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.Immunoelectrophoresis: A technique that combines protein electrophoresis and double immunodiffusion. In this procedure proteins are first separated by gel electrophoresis (usually agarose), then made visible by immunodiffusion of specific antibodies. A distinct elliptical precipitin arc results for each protein detectable by the antisera.Hyperlipoproteinemia Type V: A severe type of hyperlipidemia, sometimes familial, that is characterized by the elevation of both plasma CHYLOMICRONS and TRIGLYCERIDES contained in VERY-LOW-DENSITY LIPOPROTEINS. Type V hyperlipoproteinemia is often associated with DIABETES MELLITUS and is not caused by reduced LIPOPROTEIN LIPASE activity as in HYPERLIPOPROTEINEMIA TYPE I .Abetalipoproteinemia: An autosomal recessive disorder of lipid metabolism. It is caused by mutation of the microsomal triglyceride transfer protein that catalyzes the transport of lipids (TRIGLYCERIDES; CHOLESTEROL ESTERS; PHOSPHOLIPIDS) and is required in the secretion of BETA-LIPOPROTEINS (low density lipoproteins or LDL). Features include defective intestinal lipid absorption, very low serum cholesterol level, and near absent LDL.Dimyristoylphosphatidylcholine: A synthetic phospholipid used in liposomes and lipid bilayers for the study of biological membranes.Receptors, Scavenger: A large group of structurally diverse cell surface receptors that mediate endocytic uptake of modified LIPOPROTEINS. Scavenger receptors are expressed by MYELOID CELLS and some ENDOTHELIAL CELLS, and were originally characterized based on their ability to bind acetylated LOW-DENSITY LIPOPROTEINS. They can also bind a variety of other polyanionic ligand. Certain scavenger receptors can internalize micro-organisms as well as apoptotic cells.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Oleic Acid: An unsaturated fatty acid that is the most widely distributed and abundant fatty acid in nature. It is used commercially in the preparation of oleates and lotions, and as a pharmaceutical solvent. (Stedman, 26th ed)Chromatography, Gel: Chromatography on non-ionic gels without regard to the mechanism of solute discrimination.Molecular Weight: The sum of the weight of all the atoms in a molecule.Arteriosclerosis: Thickening and loss of elasticity of the walls of ARTERIES of all sizes. There are many forms classified by the types of lesions and arteries involved, such as ATHEROSCLEROSIS with fatty lesions in the ARTERIAL INTIMA of medium and large muscular arteries.Biological Transport: The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.Lipolysis: The metabolic process of breaking down LIPIDS to release FREE FATTY ACIDS, the major oxidative fuel for the body. Lipolysis may involve dietary lipids in the DIGESTIVE TRACT, circulating lipids in the BLOOD, and stored lipids in the ADIPOSE TISSUE or the LIVER. A number of enzymes are involved in such lipid hydrolysis, such as LIPASE and LIPOPROTEIN LIPASE from various tissues.Sterol O-Acyltransferase: An enzyme that catalyzes the formation of cholesterol esters by the direct transfer of the fatty acid group from a fatty acyl CoA derivative. This enzyme has been found in the adrenal gland, gonads, liver, intestinal mucosa, and aorta of many mammalian species. EC 2.3.1.26.Rats, Inbred Strains: Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.Callitrichinae: A subfamily in the family CEBIDAE that consists of four genera: CALLITHRIX (marmosets), CALLIMICO (Goeldi's monkey), LEONTOPITHECUS (lion tamarins), and SAGUINUS (long-tusked tamarins). The members of this family inhabit the tropical forests of South and Central America.High-Density Lipoproteins, Pre-beta: A highly dense subclass of the high-density lipoproteins, with particle sizes below 7 nm. They are also known as nascent HDL, composed of a few APOLIPOPROTEIN A-I molecules which are complexed with PHOSPHOLIPIDS. The lipid-poor pre-beta-HDL particles serve as progenitors of HDL3 and then HDL2 after absorption of free cholesterol from cell membranes, cholesterol esterification, and acquisition of apolipoproteins A-II, Cs, and E. Pre-beta-HDL initiate the reverse cholesterol transport process from cells to liver.Lipase: An enzyme of the hydrolase class that catalyzes the reaction of triacylglycerol and water to yield diacylglycerol and a fatty acid anion. It is produced by glands on the tongue and by the pancreas and initiates the digestion of dietary fats. (From Dorland, 27th ed) EC 3.1.1.3.Liposomes: Artificial, single or multilaminar vesicles (made from lecithins or other lipids) that are used for the delivery of a variety of biological molecules or molecular complexes to cells, for example, drug delivery and gene transfer. They are also used to study membranes and membrane proteins.Receptors, LDL: Receptors on the plasma membrane of nonhepatic cells that specifically bind LDL. The receptors are localized in specialized regions called coated pits. Hypercholesteremia is caused by an allelic genetic defect of three types: 1, receptors do not bind to LDL; 2, there is reduced binding of LDL; and 3, there is normal binding but no internalization of LDL. In consequence, entry of cholesterol esters into the cell is impaired and the intracellular feedback by cholesterol on 3-hydroxy-3-methylglutaryl CoA reductase is lacking.Oleic Acids: A group of fatty acids that contain 18 carbon atoms and a double bond at the omega 9 carbon.Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Lecithin Acyltransferase Deficiency: An autosomal recessively inherited disorder caused by mutation of LECITHIN CHOLESTEROL ACYLTRANSFERASE that facilitates the esterification of lipoprotein cholesterol and subsequent removal from peripheral tissues to the liver. This defect results in low HDL-cholesterol level in blood and accumulation of free cholesterol in tissue leading to a triad of CORNEAL OPACITY, hemolytic anemia (ANEMIA, HEMOLYTIC), and PROTEINURIA.Hyperlipidemia, Familial Combined: A type of familial lipid metabolism disorder characterized by a variable pattern of elevated plasma CHOLESTEROL and/or TRIGLYCERIDES. Multiple genes on different chromosomes may be involved, such as the major late transcription factor (UPSTREAM STIMULATORY FACTORS) on CHROMOSOME 1.Protein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.Antigens, CD36: Leukocyte differentiation antigens and major platelet membrane glycoproteins present on MONOCYTES; ENDOTHELIAL CELLS; PLATELETS; and mammary EPITHELIAL CELLS. They play major roles in CELL ADHESION; SIGNAL TRANSDUCTION; and regulation of angiogenesis. CD36 is a receptor for THROMBOSPONDINS and can act as a scavenger receptor that recognizes and transports oxidized LIPOPROTEINS and FATTY ACIDS.Butter: The fatty portion of milk, separated as a soft yellowish solid when milk or cream is churned. It is processed for cooking and table use. (Random House Unabridged Dictionary, 2d ed)Hyperlipoproteinemia Type II: A group of familial disorders characterized by elevated circulating cholesterol contained in either LOW-DENSITY LIPOPROTEINS alone or also in VERY-LOW-DENSITY LIPOPROTEINS (pre-beta lipoproteins).Esterification: The process of converting an acid into an alkyl or aryl derivative. Most frequently the process consists of the reaction of an acid with an alcohol in the presence of a trace of mineral acid as catalyst or the reaction of an acyl chloride with an alcohol. Esterification can also be accomplished by enzymatic processes.Glycoproteins: Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.Emulsions: Colloids formed by the combination of two immiscible liquids such as oil and water. Lipid-in-water emulsions are usually liquid, like milk or lotion. Water-in-lipid emulsions tend to be creams. The formation of emulsions may be aided by amphiphatic molecules that surround one component of the system to form MICELLES.Salmonidae: A family of anadromous fish comprising SALMON; TROUT; whitefish; and graylings. They are the most important food and game fishes. Their habitat is the northern Atlantic and Pacific, both marine and inland, and the Great Lakes. (Nelson: Fishes of the World, 1976, p97)Binding, Competitive: The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.Cholesterol, Dietary: Cholesterol present in food, especially in animal products.Reference Standards: A basis of value established for the measure of quantity, weight, extent or quality, e.g. weight standards, standard solutions, methods, techniques, and procedures used in diagnosis and therapy.Iodine Radioisotopes: Unstable isotopes of iodine that decay or disintegrate emitting radiation. I atoms with atomic weights 117-139, except I 127, are radioactive iodine isotopes.Electrophoresis, Agar Gel: Electrophoresis in which agar or agarose gel is used as the diffusion medium.Oils: Unctuous combustible substances that are liquid or easily liquefiable on warming, and are soluble in ether but insoluble in water. Such substances, depending on their origin, are classified as animal, mineral, or vegetable oils. Depending on their behavior on heating, they are volatile or fixed. (Dorland, 28th ed)AnguillaAtherosclerosis: A thickening and loss of elasticity of the walls of ARTERIES that occurs with formation of ATHEROSCLEROTIC PLAQUES within the ARTERIAL INTIMA.Chromatography, Agarose: A method of gel filtration chromatography using agarose, the non-ionic component of agar, for the separation of compounds with molecular weights up to several million.Hypolipidemic Agents: Substances that lower the levels of certain LIPIDS in the BLOOD. They are used to treat HYPERLIPIDEMIAS.Centrifugation, Density Gradient: Separation of particles according to density by employing a gradient of varying densities. At equilibrium each particle settles in the gradient at a point equal to its density. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Hypobetalipoproteinemias: Conditions with abnormally low levels of BETA-LIPOPROTEINS (low density lipoproteins or LDL) in the blood. It is defined as LDL values equal to or less than the 5th percentile for the population. They include the autosomal dominant form involving mutation of the APOLIPOPROTEINS B gene, and the autosomal recessive form involving mutation of the microsomal triglyceride transfer protein. All are characterized by low LDL and dietary fat malabsorption.Radioimmunoassay: Classic quantitative assay for detection of antigen-antibody reactions using a radioactively labeled substance (radioligand) either directly or indirectly to measure the binding of the unlabeled substance to a specific antibody or other receptor system. Non-immunogenic substances (e.g., haptens) can be measured if coupled to larger carrier proteins (e.g., bovine gamma-globulin or human serum albumin) capable of inducing antibody formation.Circular Dichroism: A change from planar to elliptic polarization when an initially plane-polarized light wave traverses an optically active medium. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Electrophoresis: An electrochemical process in which macromolecules or colloidal particles with a net electric charge migrate in a solution under the influence of an electric current.Protein Structure, Secondary: The level of protein structure in which regular hydrogen-bond interactions within contiguous stretches of polypeptide chain give rise to alpha helices, beta strands (which align to form beta sheets) or other types of coils. This is the first folding level of protein conformation.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Dansyl Compounds: Compounds that contain a 1-dimethylaminonaphthalene-5-sulfonyl group.Polymorphism, Genetic: The regular and simultaneous occurrence in a single interbreeding population of two or more discontinuous genotypes. The concept includes differences in genotypes ranging in size from a single nucleotide site (POLYMORPHISM, SINGLE NUCLEOTIDE) to large nucleotide sequences visible at a chromosomal level.Dyslipidemias: Abnormalities in the serum levels of LIPIDS, including overproduction or deficiency. Abnormal serum lipid profiles may include high total CHOLESTEROL, high TRIGLYCERIDES, low HIGH DENSITY LIPOPROTEIN CHOLESTEROL, and elevated LOW DENSITY LIPOPROTEIN CHOLESTEROL.beta 2-Glycoprotein I: A 44-kDa highly glycosylated plasma protein that binds phospholipids including CARDIOLIPIN; APOLIPOPROTEIN E RECEPTOR; membrane phospholipids, and other anionic phospholipid-containing moieties. It plays a role in coagulation and apoptotic processes. Formerly known as apolipoprotein H, it is an autoantigen in patients with ANTIPHOSPHOLIPID ANTIBODIES.Biological Markers: Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Coronary Disease: An imbalance between myocardial functional requirements and the capacity of the CORONARY VESSELS to supply sufficient blood flow. It is a form of MYOCARDIAL ISCHEMIA (insufficient blood supply to the heart muscle) caused by a decreased capacity of the coronary vessels.Acute-Phase Reaction: An early local inflammatory reaction to insult or injury that consists of fever, an increase in inflammatory humoral factors, and an increased synthesis by hepatocytes of a number of proteins or glycoproteins usually found in the plasma.Hypercholesterolemia: A condition with abnormally high levels of CHOLESTEROL in the blood. It is defined as a cholesterol value exceeding the 95th percentile for the population.Phospholipid Transfer Proteins: A ubiquitous family of proteins that transport PHOSPHOLIPIDS such as PHOSPHATIDYLINOSITOL and PHOSPHATIDYLCHOLINE between membranes. They play an important role in phospholipid metabolism during vesicular transport and SIGNAL TRANSDUCTION.Clusterin: A highly conserved heterodimeric glycoprotein that is differentially expressed during many severe physiological disturbance states such as CANCER; APOPTOSIS; and various NEUROLOGICAL DISORDERS. Clusterin is ubiquitously expressed and appears to function as a secreted MOLECULAR CHAPERONE.Protein Conformation: The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).Placental Lactogen: A polypeptide hormone of approximately 25 kDa that is produced by the SYNCYTIOTROPHOBLASTS of the PLACENTA, also known as chorionic somatomammotropin. It has both GROWTH HORMONE and PROLACTIN activities on growth, lactation, and luteal steroid production. In women, placental lactogen secretion begins soon after implantation and increases to 1 g or more a day in late pregnancy. Placental lactogen is also an insulin antagonist.Fatty Acids: Organic, monobasic acids derived from hydrocarbons by the equivalent of oxidation of a methyl group to an alcohol, aldehyde, and then acid. Fatty acids are saturated and unsaturated (FATTY ACIDS, UNSATURATED). (Grant & Hackh's Chemical Dictionary, 5th ed)SepharoseAmino Acids: Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.Radioisotope Dilution Technique: Method for assessing flow through a system by injection of a known quantity of radionuclide into the system and monitoring its concentration over time at a specific point in the system. (From Dorland, 28th ed)Perfusion: Treatment process involving the injection of fluid into an organ or tissue.Risk Factors: An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.Hyperlipoproteinemia Type III: An autosomal recessively inherited disorder characterized by the accumulation of intermediate-density lipoprotein (IDL or broad-beta-lipoprotein). IDL has a CHOLESTEROL to TRIGLYCERIDES ratio greater than that of VERY-LOW-DENSITY LIPOPROTEINS. This disorder is due to mutation of APOLIPOPROTEINS E, a receptor-binding component of VLDL and CHYLOMICRONS, resulting in their reduced clearance and high plasma levels of both cholesterol and triglycerides.