Serum low-density lipoproteins

Jurgens, G., Hoff, H.F., Chisolm, G.M. and Esterbauer, H. (1987). Modification of human serum low density lipoprotein by oxidation - characterisation and pathophysiological implications. Chem. Phys. Lipids 45, 315-336. 

Aro, A., Tuomilehto, J., Kostiainen, E., Uusitalo, U., Pietinen, P., Boiled coffee increases serum low density lipoprotein concentration, Metabolism, 36, 1027, 1987... 

An interesting aspect of the use of biomarkers as surrogates is exemplified by the statins, which lower serum low-density lipoprotein cholesterol. It has recently been shown that their... 

Effects of crystalline nicotinic acid-induced hepatic dysfunction on serum low-density lipoprotein cholesterol and lecithin cholesteryl acyl transferase. Am J Cardiol 1998 81(6) 805-7. 

Recently the means by which pectin lowers cholesterol levels and even the validity of this effect have been questioned. Upon finding no bile salt binding capacity for soluble pectin, Baig and Cerda (76) proposed that pectin lowered serum cholesterol levels by forming insoluble complexes with the serum low density lipoproteins (LDL) which transport circulating cholesterol. Complexing of LDL by citrus pectin was observed in vitro, but the way in which pectin or some component thereof enters the blood stream to effect such binding in vivo has not been determined. 

Smith, R., Dawson, J. R., and Tanford, C., The size and number of polypeptide chains in human serum low density lipoprotein. J. Biol. Chem. 247, 3376-3381 (1972). 

S64. Swaminathan, N., and Aladjem, F., The monosaccharide composition and sequence of the carbohydrate moiety of human serum low density lipoproteins. Biochemistry 15, 1516-1522 (1976). 

N8. Nestler, J. E., Barlascini, C. O., Clore, J. N., and Blackard, W. G., Dehydroepi-androsterone reduces serum low density lipoprotein levels and body fat but does not alter insulin sensitivity in normal men. J. Clin. Endocrinol. Metab. 66,57-61 (1988). 

Benzoxazole and triazole derivatives 67 and 73b showed the highest antiatherosclerotic activity among all the investigated silacyclic S-sub-stituted heterocycles in mice maintained on high-cholesterol diet. They protected against an increase in serum low-density lipoprotein level and... 

The initial interest in rice bran oil resulted from work with the stabilized rice bran. Rice bran was shown to be equivalent in serum cholesterol reduction to oat bran in hamster trials (Table 15) (1). Two clinical studies showed rice bran reduced serum low-density lipoprotein (LDL) cholesterol in humans (49,50). Defatted bran was less effective in lowering cholesterol than full fat bran (1). The cholesterol-lowering activity was concentrated in the unsaponifiable fraction of rice bran oil (Table 16) (51). Oryzanol was found to contribute to the hypocholesterolemic activity of rice... 

Horiuchi Y> Takanohashi K, Oikawa S, Numabe A, Hishinuma A, leiri X Measurement of serum low density lipoprotein-cholesterol in patients with hypertriglycemia. Electrophoresis 2000 21 293-6. 

An interesting aspect of the use of biomarkers as surrogates is exemplified by the statins, which lower serum low-density lipoprotein cholesterol. It has recently been shown that their contribution to improved prognosis in patients with cardiovascular disease is not entirely due to lowering of cholesterol and may be related to anti-inflammatory activity. Thus, the apparently obvious surrogate turns out to be an inadequate biomarker for predicting outcome. 

Bihari-Varga (223) used DSC for the assay of glycosaminoglycans (GAG) and for the characterization of the stability of crosslinked proteins in intact human and animal tissues. By this method, age-related and pathological changes and repair reactions could be studied in various connective and vascular tissues. A typical DSC curve of human serum low-density lipoprotein (LDL) and of an aortic-GAG-LDL complex is given in Figure 7.3. A reversible endothermic transition took place in the LDL molecule at 33°C. Choiesteryl esters within the LDL core existed as an isotropic solution above this temperature and in the form of the smectic liquid crystals below it. When LDL was converted to GAG-LDL complexes, the transition temperature was increased to 40°C. 

P. Morliere, E. Kohen, J.P. Reyftmann, R. Santus, C. Kohen, J.C. Maziere, S. Goldstein, W.F. Mangel, L. Dubertret (1987). Photosensitization by porphyrins delivered to L cell fibroblasts by human serum low density lipoproteins. A microspectrofluorometric study. Photochem. PhotobioL, 46, 183-191. 

Their capacity to decrease serum low-density lipoprotein (LDL) cholesterol levels and, thus, in protecting against CVD, has led to the development of functional foods enriched with plant sterols. At present, several functional products, such as spreadable fats, yoghurts, and milk, with free phytosterols or phytosteryl fatty acid esters or phytostanyl fatty acid esters added at high levels, are available in the market, especially in several European countries. ... 

Kirby, R.W. Anderson, J.W. Slellng, B. Rees, E.D. Chen, W.L. Miller, R.E. Kay, R.M. Oat-bran Intake selectively lowers serum low-density lipoprotein cholesterol concentrations. Am. J. Clin. Nutr. 34 824, 1981. 

In 10 children who were exclusively given a fish oil-based lipid emulsion during parenteral nutrition for a median duration of 14 weeks, the serum bilirubin fell in 8 there was also a 24% increase in high-density lipoprotein cholesterol and significant falls in serum low-density lipoprotein, very low-density lipoprotein, and total cholesterol, and triglyceride concentrations /35 7-... 

Uses Thyroid hormones, levothyroxine (T4), and triiodothyronine (liothyronine, T3) are used to treat hypothyroidism. Both overt and subclinical hypothyroidism are associated with dyslipidemia, and replacement with thyroid hormones lowers the concentrations of serum low-density lipoprotein (LDL) cholesterol and has other potentially favorable actions on lipoprotein metabolism [1 ]. Consequently, thyro-mimetic drugs, which mimic the actions of thyroid hormones, hold promise as lipidlowering agents. The development of some of these drugs was discontinued because of adverse reactions related to thyroid hormone-like actions, including possible death due to cardiac causes and adverse effects on bone [2 , 3 ]. 

Increased levels of dermatan sulphate have been observed for rabbit and monkey aorta cells but not for human foreskin fibroblasts grown in the presence of human serum low-density lipoprotein. A mechanism is proposed to explain the increased deposition of lipid in the aorta due to hyperlipidaemia. 

Aronow WS, Ahn C, Gutstein H. Incidence of new atherothrombotic brain infarction to older persons with myocardial infarction and serum low-density lipoprotein cholesterol >125 mg/dL treated with statin versus no lipid-lowering drug. J Gerontol A Biol Scien Med Sci 2002 57A M333-M335. 

Chen, R. E. Miller, and R. M. Kay, Oat-bran intake selectively lowers serum low-density lipoprotein cholesterol con-... 

Gulik-Krzywicki, T., Yates, M., and Aggerbeck, L.A., 1979, Structure of serum low-density lipoprotein. II. A freeze-etching electron microscope study, J. Mol. Biol., 131 475. 

Degovics, G., and Laggner, P., 1981, Structure of two subfractions of normal porcine (sus domesticus) serum low density lipoproteins. X-ray small-angle scattering studies. Biochemistry, 20 3231. 

Laggner, P., Degovics, G., Muller, K.W., Glatter, 0., Kratky, 0., Kostner, G., and Holasek, A., 1977, Molecular packing and fluidity of lipids in human serum low density lipoproteins, Hoppe Seyler s Z. Physiol. Chem., 358 771. 

One well studied system is that of the serum low density lipoprotein (LDL sections 5.3.5(e) and 5.5.3). When the lipids of this lipoprotein are peroxidized, the apoprotein becomes fragmented and there is cross-linking and residue modification. Two products of lipid oxidation, malonaldehyde and 4-hydroxy nonenal, are responsible, the latter reacting with lysines of apoprotein-B by an addition reaction. As a result LDL no longer binds to the fibroblast receptor (section 5.5.3) and has an extended half-life in blood. 

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