• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.3
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• pp.362-370
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• 1995

Human plasma low density lipoprotein(LDL) is the main carrier for cholesterol, and recent studies suggest the normal LDL can be readily oxidized by free radical and not interact with LDL receptor. Lipoprotein pariticles are consisted of lipid andprotein, and fatty acids of lipoproteins are prone to oxidation. LDL particles readily undergo oxidative modification by copper. From the results, oxidized LDL altered its biological properties. A marked increase in the electrophoretic mobility of LDl on agarose gel indicated that negative surface charge of the LDL particles was increased. Also, the results from the HPLC showed that oxidized LDL was degraded into several polypeptides nonenzymatically. Degradation tests which measured the amount of 5-IAF labelled oxidized LDL were carried out by monocyte and hepatocyte cell culture. Hepatocyte cell culture of modified LDL did not show consistent pattern. However, binding rate of modified LDL with HMDM(human monocyte derived macrophage) was enhanced with oxidation, but was retarded by addition of antioxidants(hyaluronic acid, vitamin A, vitamin E). Also comparisons of oxidized-LDL, acetyl-LDL and MDA-LDL showed significant differences in the chemical properteis and binding affinity to HMDM. Thus, modificaition of normal LDL altered its biological properties.

• KSBB Journal
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• v.15 no.2
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• pp.156-161
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• 2000

This study was designed to investigate the antioxidative activity on oxidation of human low density lipoprotein(LDL) of band 2 fractionated from culture broth of Streptomyces sp. BH-405. Antioxidative activity of band 2 obtained from fractionation of BH-405 culture purification was measured against $Cu^{2+}$ mediated human LDL oxidation by thiobarbituric acid reactive substance. $CuSO_4$ mediated oxidation of LDL was degraded at a much higher rate than native LDL. Band 2 at a concentration of 100 or 200 !lg/mL inhibited the oxidation of LDL induced by $CuSO_4$, The formation of conjugated dienes induced in the presence of 5 !1M CuS04 of the mouse macrophage and J744. The electrophoretic mobility of the LDL in addition of $200\mu\textrm{g}$ band 2 in the presence of $5\mu\textrm{m}$ $CuSO_4$ was lower than that of native LDL. LDL modified by copper mediated or cell mediated uptake was degraded by macrophage at much greater than native LDL, and band 2 was found as potential inhibitor of modification of 125I-labelled LDL by macrophage. phage.

• BMB Reports
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• v.48 no.1
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• pp.48-53
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• 2015

Oxidized LDL (oxLDL) performs critical roles in atherosclerosis by inducing macrophage foam cell formation and promoting inflammation. There have been reports showing that oxLDL modulates macrophage cytoskeletal functions for oxLDL uptake and trapping, however, the precise mechanism has not been clearly elucidated. Our study examined the effect of oxLDL on non-muscle myosin heavy chain IIA (MHC-IIA) in macrophages. We demonstrated that oxLDL induces phosphorylation of MHC-IIA (Ser1917) in peritoneal macrophages from wild-type mice and THP-1, a human monocytic cell line, but not in macrophages deficient for CD36, a scavenger receptor for oxLDL. Protein kinase C (PKC) inhibitor-treated macrophages did not undergo the oxLDL-induced MHC-IIA phosphorylation. Our immunoprecipitation revealed that oxLDL increased physical association between PKC and MHC-IIA, supporting the role of PKC in this process. We conclude that oxLDL via CD36 induces PKC-mediated MHC-IIA (Ser1917) phosphorylation and this may affect oxLDL-induced functions of macrophages involved in atherosclerosis.

• Reproductive and Developmental Biology
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• v.36 no.3
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• pp.147-154
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• 2012

This study was designed to determine whether low-density lipoproteins (LDL) from egg yolk and taurine, hypotaurine and trehalose as antioxidant in extender improve the freezability and fertility of Korean Jeju Black Bull semen. The semen was cryopreserved with tris egg yolk extenders containing 7% glycerol and treated 4% LDL, 20 mM taurine, hypotaurine and trehalose. Frozen-thawed sperm were evaluated motility, viability, membrane, and acrosome integrity and sperm penetration ability. The results were compared to semen cryopreserved in tris egg yolk extender only as control. Frozen-thawed semen evaluation cleary indicated that the addition of LDL and LDL-antioxidants (taurine, hypotaurine and trehalose) combination were significantly improved (p<0.05) the viability (%; with staining test using eosin-Y) compared to control spermatozoa. Also, in membrane integrity (%; with supravital hypo-osmotic swelling test), not only LDL-antioxiants combination but also LDL were significantly increased (p<0.05) the swelled sperm using HOST compared to control. Sperm acrosome integrity state was classified by CTC (chlortetracycline) staining test. F pattern was significantly increased in LDL-antioxidant combination than control (p<0.05) and B pattern was not significantly differences among all treatments and control. However, AR pattern was significantly decreased in LDL-antioxidants combination than control (p<0.05). Pronucleus formation and sperm penetration index (SFI) were significantly increased in LDL and LDL-antioxidants combination than control (p<0.05). Especially, LDL-taurine significantly improved pronucleus fomation and SFI than LDL (p<0.05). It was concluded that LDL and LDL-antioxidants in extender improved the freezability and fertility of Korean Jeju Black bull spermatozoa.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.3
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• pp.530-539
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• 1994

All lipoproteins are made up of three major classes of lipids : triglycerides, cholesterol, and phospholipids. Lipoproteins vary in their relative content of these lipids as well as in size and protein content. Human low density lipoprotein (LDL) is a main carrier for cholesterol in the blood stream, and it is well established that cholesterol deposits in the arteries stem primarily from LDL and that increased levels of plasma LDL correlated with in increased risk of atherosclerosis. Various lines of research provide strong evidence that lDL may become oxidized in vivo and that oxidized-LDL is the species involved in the formation of early atherosclerotic lesions. the most crucial findings in this context are the following : (1) Oxidized -LDL has chemotactic properties and if present in the intimal space of the arteries would recruit blood monocytes which then can develop into tissue macrophages ; (2) marcrophages take up oxidized-LDL unregulated to from lipid laden foam cells ; (3) Oxdized-LDLis highly cytotoxic and could be responsible for damage of the endothelial layer and for the destruction of smooth muscle cells.

• Archives of Pharmacal Research
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• v.24 no.5
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• pp.431-436
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• 2001

The water extract of Cichorium intybus (WECI) showed a remarkable antioxidative effect on LDL, and inhibitory effects on the production of thiobarbituric acid reactive substance and the Degradation of fatty acids in LDL. Vitamin 1 and unsaturated fatty acids in LDL were protected by adding WECI from the effects of metal catalyzed LDL oxidation. From the results obtained, we conclude that LDL oxidation is inhibited in vitro by the addition of WECI, and that LDL is protected by WECI from oxidative attack, as shown by agarose gel electrohporesis.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.3
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• pp.402-408
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• 1994

Human plasma low density lipoprotein (LDL) is the major factor of coronary heart disease.But recent studies suggest the normal LDL can be realdily oxidized by oxygen free radicals and not interact with LDL receptors.Lipoprotei particles consist of lipid and protein, and fatty acids are prone to oxidatioin.The fatty acid compositions of LDL from Koreans was compared with that of Westerners.From the results, the raio of unsaturated fatty acids of korean and Westerner approximately 30 and 70%, respectively.which means Westerners are more labile in the lipid oxidation of LDL than Koreams.Normal LDL was incubated with $CuSO_4$ in PBS to lead for the peroxidation of LDL, and it was tested by the detection of TBARS and free radicals.Then, ascorbate, ${\alpha}-tocopherol$ and hyaluronic acid were found to have effects of antioxidants on LDL oxidation.The amount of free radical increased as the extent of oxidation increased.The time course of free radical formation was similar to TBARS.Therefore, determination of free radical by Luminometer was much more convenient than that of TBARS.

• BMB Reports
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• v.33 no.2
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• pp.148-154
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• 2000

The glycation process plays an important role in accelerated atherosclerosis in diabetes, and the uptake of atherogenic lipoproteins by macrophage in the intima of the vessel wall leads to foam cell formation, an early sign of atherosclerosis. Besides the lipolytic action on the plasma triglyceride component, lipoprotein lipase (LPL) has been reported to enhance the cholesterol uptake by arterial wall cells. In this study, some properties of LPL-mediated low-density lipoprotein (LDL) uptake and the effect of LDL glycation were investigated in RAW 264.7 cell, a murine macrophage cell line. In the presence of LPL, $^{125}I$-LDL binding to RAW 264.7 cells was increased in a dose-dependent manner. At concentrations greater than $20\;{\mu}g/ml$ of LPL, LPL-mediated LDL binding was increased about 17-fold, achieving saturation. Without LPL, both very low-density lipoprotein (VLDL) and high-density lipoprotein (HDL) were ineffective in blocking the binding of $^{125}I$-LDL to Cells. However, LPL-enhanced LDL binding was inhibited about 50% by the presence of VLDL, while no significant effect was observed with HDL. Heat inactivation of LPL caused a 30% decrease of LDL binding. In the presence of LPL, the cells took up 40% of cell-bound native LDL. No significant difference was observed in cell binding between native and glycated LDL. However, the uptake of glycated LDL was significantly greater than that of native LDL, reaching to 70% of the total cell bound glycated LDL. These results indicate that LPL can cause the significant enhancement of LDL uptake by RAW 264.7 cells and the enhanced uptake of glycated LDL in the presence of LPL might play an important role in the accelerated atherogenesis in diabetic patients.

• Journal of Society of Preventive Korean Medicine
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• v.4 no.2
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• pp.205-213
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• 2000

The oxidative modification of low density lipoprotein(LDL) has been implicated in the development of atherosclerosis . Oxidized LDL(oxLDL) are found in macrophage foam cell , and it can induce an macrophage proliferation in atherosclerotic plaque. In this study, we investigated the hypothesis that Tokhwalkisaengtang(TK) may reduce atherosclerosis by lowering the oxidizability of LDL, To achieve this goal, we examined the effect of TK on LDL oxidation, nitric oxide production in murine macrophage cell line , and the effect of TK on cupuric sulfate-induced cytotoxicity. LDH release, and macrophage activity TK inhibited the generation of oxLDL from native LDL in macrophage cell culture, and decreased the release of LDH from cupric sulfate-stimulated macrophage. In other experiments, TK activated macrophase cell, and increased the survival rate, and enhanced nitric oxide production in macrophage.

• Korean Journal of Food Science and Technology
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• v.28 no.5
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• pp.850-858
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• 1996

Green tea leaves 12.5 g were extracted twice with 500 ml boiling water. The green tea extract (GTE) contained 4.67 mg solid. The GTE contained polyphenols sush as 54.12% (-) epicatechin gallate, 26.21% (-) epicatechin, 10.71% epicatechin gallate, 7.09% (-) epicatechin and 1.85% catechin. The GTE inhibited the copper-catalyzed oxidation of human LDL at the concentrations of 50 and $100\;{\mu}g/ml$ GTE in the presence of $5\;{\mu}M$ $CuSO_{4}$. The electrophoretic mobility of the LDL oxidized in the presence of $5\;{\mu}M\;CuSO_{4}$ was higher than that of the native LDL. The GTE also inhibited LDL oxidation induced by J774, human monocyte-derived macrophages and vascular endotherial cells. The LDL modified by copper or cells was inhibited by human macrophages at a much greater rate than native LDL in the presence of GTE. The GTE was found to be a potent inhibitor of modification of LDL. GTE inhibited the uptake of cell-modified $^(125)I-labelled$ LDL by macrophages. The formation of conjugated dienes was strongly inhibited in the presence of 50 or $100\;{\mu}g/ml$ GTE.