VLDL-LDL

FIGURE 4.29 Relation between molecular weight of lipoproteins and elution volume for combination GFC columns. Column 7.5 mm i.d. X 60 cm. Sample Chylomicron, VLDL, LDL, HDLj, HDL3, albumin, and ovalbumin. Elution 0.1 hA Tris—HCI buffer (pH 7.4). Flow rate 1.0 ml/min. 

HDL and VLDL are assembled primarily in the endoplasmic reticulum of the liver (with smaller amounts produced in the intestine), whereas chylomicrons form in the intestine. LDL is not synthesized directly, but is made from VLDL. LDL appears to be the major circulatory complex for cholesterol and cholesterol esters. The primary task of chylomicrons is to transport triacylglycerols. Despite all this, it is extremely important to note that each of these lipoprotein classes contains some of each type of lipid. The relative amounts of HDL and LDL are important in the disposition of cholesterol in the body and in the development of arterial plaques (Figure 25.36). The structures of the various... 

Antibodies to very low density lipoprotein (VLDL) and LDL have been detected in the serum of patients with RA, but not control groups (Lazarevic et al., 1993). In these studies, 38% of patients with active RA tested positive for anti-VLDL/LDL antibodies whilst these autoantibodies were not detected in patients with psoriatic arthritis, osteoarthritis or healthy subjects. Lipoproteins were found in the dissociated components of circulating immune complexes in the serum of 30% of the RA patients. It was concluded that dyslipoproteinaemia in some RA patients may be due to an autoimmune component of the disease. 

Astaxanthin has been suggested as a potential dietary supplement to improve retinal function (Hussein et al., 2006 Parisi et al., 2008). While normally astaxanthin is not present in human plasma, a high dose of dietary astaxanthin does result in its appearance in appreciable concentrations within the plasma where it is bound mainly to the lipoproteins, VLDL, LDL, and HDL (Coral-Hinostroza et al., 2004). To our knowledge, to date there is no report identifying astaxanthin in human retina. 

Finally, dyslipidemia is a feature of FXR knockout mice levels of VLDL, LDL and HDL cholesterol and ApoB lipoproteins are increased concomitant with reduced clearance of HDL cholesteryl ester and elevated triglyceride and free fatty-acid levels. ... 

According to their electrophoretic mobility in supporting media, e.g., paper, agarose, or cellulose acetate, serum lipoproteins can be defined as pre-)8, j8-, and ai-lipoproteins, grossly corresponding to VLDL, LDL, and... 

For the convenience of the reader, we have outlined the method of sequential flotation employed in our laboratory for separating chylomicrons VLDL, LDL, HDLa, HDLs, VHDL, and d> 1.25 bottom (Table 1). This method, the result of years of experience, has been highly reproducible in terms of the normal human population examined in this laboratory. Such a method may not necessarily apply to dyslipoproteinemic states, where modifications may be necessary, depending on the type of abnormality under consideration. It should also be stressed that any lipoprotein isolated is in need of purification this may be achieved by ultracentrifugation based on the assumption that contaminants are in loose association with the main complex. Whenever this purification is not achieved, other methods may be used as outlined below. For a discussion of the application of density gradient ultracentrifugation to the study of plasma lipoproteins, the reader is referred to a recent review (L3). 

Parameters Chylomicrons VLDL LDL HDLj HDLs VHDLi... 

The development of technology for the isolation, fractionation, and purification of the principal polypeptides of VLDL, LDL, and HDL is undoubtedly a major achievement in the area of lipoprotein research. The availability of such polypeptides in pure form has permitted studies on their characterization and the definition of their chemical, physical, and immunological properties. The primary structure of many of these poly-... 

Pheromone (sex attractant). Ether extract of the stem, produced equivocal effect on Aspiculuris tetraptera, female and male Dacus dorsalis, male Mediterranean fruit flies, and male and female melon flies " k Pheromone (signaling). Ether extract of the stem, produced equivocal effect on Aspiculuris tetraptera, female and male Dacus dorsalis, male Mediterranean fruit flies, and male and female melon flies " k Phospholipidemic effect. Oil, administered to phospholipids transfer protein knockout (PLTPO)-deficient mice, produced an increase of phospholipids and free cholesterol in the VLDL-LDL region of PLTPO mice. Accumulation of phospholipids and free cholesterol was dramatically increased in PLTPO/HLO mice compared to PLTPO mice. Turnover studies indicated that coconut oil was associated with delayed catabolism of phospholipids and phospho-lipids/free cholesterol-rich particles. Incubation of these particles with hepatocytes of coconut-fed mice produced a reduced removal of phospholipids and free cholesterol by SRBI, even though SRBI protein expression levels were unchanged . 

Mechanism of Action Afibricacid derivative that inhibits lipolysis of fat in adipose tissue decreases liver uptake of free fatty acids and reduces hepatic triglyceride production. Inhibits synthesis of VLDL carrier apolipoprotein B. Therapeutic Effect Lowers serum cholesterol and triglycerides (decreases VLDL, LDL increases HDL). Pharmacokinetics Well absorbed from the GI tract. Protein binding 99%. Metabolized in liver. Primarily excreted in urine. Not removed by hemodialysis. Half-life 1.5 hr. 

Atherosclerosis is main cause of cardiovascular deaths. It is characterized by a localised plaque in the intima and is composed of cholesterol esters, deposition of fibrous proteins and calcification. These plaques may narrow the arterial lumen and can cause distalischemia. The coronary and cerebral circulation are main sites of atherosclerosis. Raised levels of VLDL, LDL... 

VLDL, LDL increased Niacin, reductase inhibitor Niacin or fibrate plus reductase inhibitor2... 

Decreases catabolism of apo AI treduces VLDL secretion from liver Increases HDL decreases lipoprotein(a) [Lp(a)], LDL, and triglycerides Low HDL elevated VLDL, LDL, Lp(a) Oral large doses Toxicity Gastric irritation, flushing, low incidence of hepatic toxicity may reduce glucose tolerance... 

A method for determination of TBARS in the plasma of a 50 p,L blood sample is based on FLD of 169, instead of the usual UVD, with Xex =515 nm and Xn = 553 nm455. The lipoprotein in human serum can be separated into three fractions, VLDL, LDL and HDL, by a series of precipitation and centrifugation operations, carried out in the presence of EDTA and GSH (28) to avoid oxidation. In TBARS measurements carried out for serum by the fluorescence method (Xex =515 nm, Xa = 548 nm) it was found that 43% was bound to the lipoproteins, distributed as follows VLDL + LDL 27% and HDL 16%456. 

GSLC Plasma LDL hdl9 Plasma VLDL LDL HDL2 HDL0 Plasma LDL... 

In kindreds with this disorder, individuals may have elevated levels of VLDL, LDL, or both, and the pattern may change with time. Familial combined hyperlipoproteinemia involves an approximate doubling in VLDL secretion. It seems to be transmitted as a semidominant trait. Triglycerides can be increased by the factors noted above. Elevations of cholesterol and triglycerides are generally moderate, and xanthomas are usually absent. Drug treatment is warranted because the risk of coronary atherosclerosis is increased and diet alone does not normalize lipid levels. A reductase inhibitor or ezetimibe in combination with niacin is usually required to treat these patients. 

In Taiwan, Huang et al. investigated the correlation between serum lipid, lipoprotein concentrations and major depressive disorder in patients admitted for general health screening [33]. They found that the ratios of TC/HDL and LDL/HDL showed significant differences between patients with major depressive disorder and normal controls in women. Huang and Chen also pointed out that no significant differences were found in lipid concentrations of TC, TG, HDL, VLDL, LDL, TC/HDL, and LDL/HDL between patients with dysthymia and normal controls [41],... 

With one exception, all apolipoproteins appear to exchange between plasma lipoproteins. The exception is apoB, an apolipoprotein that is present in all chylomicrons and VLDL, LDL, and Lp(a) particles, and which seems to be structurally essential to the integrity of these particles. It appears likely... 

W14. Whayne, T. F., Alaupovic, P., Curry, M. D., Lee, E. T., Anderson, P. S., andSchecter, E., Plasma apolipoprotein B and VLDL-, LDL-, and HDL-cholesterol as risk factors in the development of coronary artery disease in male patients examined by angiography. Atherosclerosis 39, 411-424 (1981). 

Parenchymal liver cells Kupffer cells Liver endothelial cells Leucocytes Galactose, polymeric IgA, cholesterol ester-VLDL, LDL Mannose-fucose, galactose (particles), (oxidized) LDL Mannose, acetylated LDL Chemotactic peptide, complement C3b... 

Cholesterol is found in all lipoprotein particles but is relatively concentrated in LDL and HDL, whereas triglycerides are relatively concentrated in chylomicrons and VLDL. Heart disease appears to correlate with increased LDL and decreased HDL. Elevated HDL generally is a favorable finding, as HDL shunts excess cholesterol back to the liver (via LDL remnant particles) where it can be excreted. Chylomicrons, VLDL, and LDL, on the other hand, carry triglycerides and cholesterol to the periphery (fig. 6.4). The more significant clinical conditions involve elevation of cholesterol, triglycerides, VLDL, LDL, and/or chylomicrons, rather than HDL. 

Lipoproteins contain protein subunits along with lipids. Depending upon density and lipid compound they are further classified as VLDL. LDL and HDL. 

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