Lipoprotein low-density lipoproteins and

A lipid profile (cholesterol, high-density lipoprotein, low-density lipoprotein, and triglycerides) and complete blood count were determined before and after four weeks of treatment for all patients. 

Vertebrate, especially mammalian, lipoproteins have been extensively studied. In the invertebrate world, only insect lipoproteins have received serious attention. Whereas vertebrates rely on a battery of lipoproteins (chylomicrons, very low-density lipoproteins, low-density lipoproteins, and high-density lipoproteins) to effect lipid transport, insects use primarily a single type of lipoprotein, lipophorin, for lipid transport. Lipophorin is both more versatile than vertebrate lipoproteins in terms of the diverse lipids it transports and more efficient than vertebrate lipoproteins in that, for the most part, it delivers lipids to tissues without being internalized and destroyed. We believe that new insights can be obtained from an understanding of insect lipoproteins, and in this article we review the current state of knowledge about the structure and metabolism of lipophorins. 

Chylomicrons, high-density lipoproteins, low-density lipoproteins, and very low density lipoproteins Atherosclerosis results when cholesterol and other substances coat the arteries causing a narrowing of the passageways. As the passageways become narrower, greater pressure is required to provide adequate blood flow. This results in higher blood pressure (hypertension). 

The rotational mobility of human low-density (LDL) and very-low-density (VLDL) lipoproteins was studied as a function of viscosity and temperature in the range of —90 to — 50°C.(86)The rotational behavior for LDL is represented by a single correlation time, consistent with the overall rotation of a spherical rigid particle as the source of the phosphorescence depolarization. For VLDL, internal peptide motions dominate the depolarization profile. 

Lipoproteins are divided into five basic types. The largest particles are the chylomicrons, followed by the very low-density lipoproteins, intermediate lipoproteins, low-density proteins, and finally the smallest— high-density lipoproteins. Separation of the aforementioned cholesterol-containing complexes is accomplished by ultracentrifugation. 

Atherosclerosis is the leading cause of death for both genders in the USA and other Western countries. Lipoproteins that contain apolipoprotein (apo) B-100 convey lipids into the artery wall. These are low-density (LDL), intermediate-density (IDL), very-low-density (VLDL), and lipoprotein(a) (Lp[a]). 

The small particles of plasma lipoprotein, which carry triacylglycerols, can be separated according to their buoyant densities by centrifugation. They have been classified into five groups of increasing density but smaller size as chylomicrons, very low density lipoproteins (VLDL), intermediate density lipoproteins (IDL), low density (LDL), and high density lipoproteins (HDL) (Table 21-1 and Fig. 21-2). Each lipoprotein particle contains one or more apolipoproteins (Table 21-2), whose sizes vary from the enormous 4536-residue apoB-100 to apoC-II and apoC-III, each of which contains just 79 residues73 and the 57-residue apoC-I.7b... 

Dielschy, J. M. (1997). Theoretical considerations of what regulates low-density-lipoprotcln and high-density-lipoprotein cholesterol. Am. /. Cfjn. Nutr. 65,1581S 1.5S9S. 

Lipid changes seen with the most widely used combined oral contraceptives comprise an increase in low density hpoprotein and reductions in high density lipoprotein and cholesterol. The third-generation products have these effects to a much smaller extent, leading to claims that they would be less hkely to have long-term adverse cardiovascular effects related to atherosclerosis. However, such a claim reflects an all too readily adopted belief that the hpid changes produced by the more traditional combined oral contraceptives are in this respect capable of causing this type of (primarily arterial) cardiovascular disease. This is of itself far from certain. 

Coronary heart disease (CHD) is one of the leading causes of morbidity and mortality in the United States. Hyperlipidemia is a major risk factor for atherosclerosis and CHD. Hyperlipidemia is defined as an elevation in blood cholesterol or triglycerides (TG). Lipids are primarily transported in the body by three major lipoproteins low-density (LDL), very-low-density (VLDL), and high-density lipoproteins (HDL). Cholesteryl esters and TG are carried by the lipoproteins, which vary in size and composition of cholesterol and... 

The classification into chylomicrons (CM), very low density (VLDL), low density (LDL), and high density (HDL) lipoproteins is based on their relative contents of protein and lipid that determine the densities of these lipoprotein classes. CM have only 1-2% protein while HDL have about 50% protein by weight. The diameters of lipoproteins are inversely correlated with their densities and range from about 6000 A for CM to 70 A for the smallest HDL (Fig. 1). 

The applicability of 13C nmr to human serum lipoproteins has been demonstrated (Hamilton et al., 1973, 1974). Spectra and partial peak assignments for high-density (HDL), low-density (LDL), and... 

All lipoprotein concentrations are expressed in mg/lOOml, using specific refractive increments equivalent to values used by de Lalla and Gofman (2) a value of 0.00154 An/gm/100ml is used for the Sf 0-400 low-density spectrum, and a calculated value of 0.00149 An/gm/100 ml is used for the high-density lipoprotein spectrum. All x values are in radial distance (cm) from the center of rotation of the analytical rotor. Other symbols used are ... 

The plasma lipoproteins can be divided into various low density (LDL) and high density (HDL) varieties, the latter having the highest phospholipid content (Table 11.7). 

There is a constant interchange of phospholipids between high- and low-density proteins and between these and the phospholipids in red blood cells. Each type of lipoprotein has a different bio function (Figure 11.5). 

Shirai K, Fitzharris TJ, Shinomiya M, Muntz HG, Harmony JAK, Jackson RL, Quinn DM (1983) Lipoprotein Upase-catalysed hydrolysis of phosphatidylcholine of guinea pig very low density Upoproteins and discoidal complexes of phosphoHpid and apoUpoprotein effect of apoHpopro-tein C-II on the catalytic mechanism. J Lipid Res 24 721-730... 

PHB is non toxic. It is found in variety of plant and animal tissues. In human plasma, PHB can be found associated with very low density hpoprotein and low density lipoprotein. In addition, a significant portion of PHB is found associated with serum albumin (Madison and Huisman, 1999). Comparative account of properties of PHA and synthetic plastics as presented in Table 5. 

High-density Hpoprotein, low-density hpoprotein, and very low density lipoprotein (cholesterol)... 

A lipid-protein complex that is water soluble. Hence, it is involved in the transport of lipids in the blood. Four types of lipoprotein circulate in the blood, all of which contain the lipids, triglycerides, cholesterol, and phospholipid in varying proportions. The four types of lipoprotein are (1) chylomicrons—lowest density (2) very low density, VLDL (3) low density, LDL and (4) high density, HDL. 

Cholesterol is biosynthesized in the liver trans ported throughout the body to be used in a va riety of ways and returned to the liver where it serves as the biosynthetic precursor to other steroids But cholesterol is a lipid and isn t soluble in water How can it move through the blood if it doesn t dis solve in if The answer is that it doesn t dissolve but IS instead carried through the blood and tissues as part of a lipoprotein (lipid + protein = lipoprotein) The proteins that carry cholesterol from the liver are called low density lipoproteins or LDLs those that return it to the liver are the high-density lipoproteins or HDLs If too much cholesterol is being transported by LDL or too little by HDL the extra cholesterol builds up on the walls of the arteries caus mg atherosclerosis A thorough physical examination nowadays measures not only total cholesterol con centration but also the distribution between LDL and HDL cholesterol An elevated level of LDL cholesterol IS a risk factor for heart disease LDL cholesterol is bad cholesterol HDLs on the other hand remove excess cholesterol and are protective HDL cholesterol IS good cholesterol... 

Fig. 4.29 (page 126), very large proteins, such as low-density lipoproteins (LDL and VLDL), gelatin, and sea worm chlorocruorin, which are excluded even by G4000SW columns, can be covered by PW columns of large pore size such as the G5000PWxl and G6000PWxl columns. 

Anion exchange resins are basic polymers with a high affinity for anions. Because different anions compete for binding to them, they can be used to sequester anions. Clinically used anion exchange resins such as cholestyramine are used to sequester bile acids in the intestine, thereby preventing their reabsorption. As a consequence, the absorption of exogenous cholesterol is decreased. The accompanying increase in low density lipoprotein (LDL)-receptors leads to the removal of LDL from the blood and, thereby, to a reduction of LDL cholesterol. This effect underlies the use of cholestyramine in the treatment of hyperlipidaemia. 

As yet, no human diseases have been identified as a result of FATPl mutations. However, genetic polymorphisms in the human FATPl gene have been linked to dyslipidemia. An A/G exchange at position +48 in intron 8 of the FATPl gene has been shown to result in increased TG concentrations in female but not in male subjects. In a second study, the same polymorphism was linked to increased postprandial TG concentrations and smaller low density lipoprotein (LDL) particles. To date, it is still unknown if this polymorphism is associated with altered levels of FATPl expression and/or function. 

Cells in the atheroma derived from both macrophages and smooth muscle cells that have accumulated modified low-density lipoproteins. Their cytoplasm laden with lipid causes the foamy appearance on microscopy... 

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