Browsing by Author "Jayakumari, N."

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    Electroelution of lipoprotein(a) [Lp(a)] from native polyacrylamide gels: A new, simple method to purify Lp(a)
    (JOURNAL OF BIOCHEMICAL AND BIOPHYSICAL METHODS, 2006)
    Lipoprotein(a), Lp(a), is an atherogenic lipoprotein consisting of an LDL like core particle and a covalently linked glycoprotein of variable size. Lp(a). isolated front serum always contains LDL and HDL, as contaminants since Lp(a) floats in the density range 1.05-1.12 g/ml which overlaps that of LDL and HDL, Purified Lp(a) is increasingly needed as a standard to overcome various problems in the standardization of Lp(a) measurements and for in vitro biological studies. Problems inherent to the purification of Lp(a) include the aggregation of Lp(a) with LDL, overlapping size distribution and the inability of some fractions to bind to affinity columns. Here. we describe the development of a new method to purify Lp(a) from contaminating LDL and HDL, particles. Lp(a) was isolated from serurn by sequential ultracentrifugation, resolved by native polyacrylamide eel electrophoresis and the eel segments were electroeluted to obtain pure Lp(a). L-Proline was added to the sample to a final concentration of 0.1 M to prevent the aggregation of Lp(a) with LDL. (c) 2006 Elsevier B.V. All rights reserved.
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    Oxidatively modified high density lipoprotein promotes inflammatory response in human monocytes-macrophages by enhanced production of ROS, TNF-alpha, MMP-9, and MMP-2
    (MOLECULAR AND CELLULAR BIOCHEMISTRY, 2012)
    It has been proposed that high-density lipoprotein (HDL) loses its cardioprotective ability through oxidative modifications by reactive oxygen species (ROS) and promote atherogenesis. However, the pro-atherogenic pathways undergone by oxidized HDL remain poorly understood. Since monocytes play a crucial role in atherogenesis, this study was aimed to investigate the influence of both native and oxidized HDL (oxHDL) on monocytes-macrophages functions relevant to atherogenesis. HDL particles were isolated from human blood samples by ultracentrifugation and subjected to invitro oxidation with CuSO4. The extent of oxidation was quantitated by measurement of lipid peroxides. Human peripheral blood mononuclear cells were isolated and cultured under standard conditions. Cells were treated with native and oxHDL at varying concentrations for different time intervals and used for several analyses. Intracellular ROS production was assessed based on ROS-mediated DCFH fluorescence of the cells. The release of TNF-alpha and matrix metalloproteinases (MMPs) was quantitated using ELISA kit and gelatine zymography, respectively. Treatment of cells with oxidized HDL enhanced the production of ROS in a concentration-dependent way, while native HDL had no such effect. Further, the release of TNF-alpha, MMP-9, and MMP-2 was found to be remarkably higher in cells incubated with oxHDL than that of native HDL. Results demonstrate that oxidative modification of HDL induces pro-inflammatory response and oxidative stress in human monocytes-macrophages.