Browsing by Author "Jayakumari, N"

Now showing 1 - 9 of 9
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    A Simple Economical Method for Assay of Atherogenic Small Dense Low-Density Lipoprotein-Cholesterol (sdLDL-C).
    (Indian journal of clinical biochemistry : IJCB, 2011)
    In the present study, we report a simple and economical precipitation method for the quantitative determination of small, dense LDL-cholesterol (sdLDL-C) in serum that is considered to be an emerging risk factor for cardiovascular disease. This method consisted of precipitation of lipoproteins of density <1.044g/ml using heparin-MnCl(2) and quantification of cholesterol existed in the supernatant using reagents for routine cholesterol assay instead of the costly direct low density lipoprotein-cholesterol assay kit. The supernatant contained sdLDL and high-density lipoprotein (HDL) that was confirmed by polyacrylamide gel electrophoresis. sdLDL-C concentration can be calculated by subtracting the HDL-C value from the total cholesterol concentration of the supernatant. sdLDL-C values obtained by this modified method were similar to those obtained by direct assay of sdLDL-C and there was significant correlation between the two methods. In conclusion, this method is highly economical, do not require special equipments and is useful to evaluate atherogenic risk.
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    Circulating Thrombotic Risk Factors in Young Patients with Coronary Artery Disease Who Are on Statins and Antiplatelet Drugs
    (Ind J Clin Biochem, 2016-02) Reema, G; Harikrishnan, S; Jayakumari, N; Anugya, B; Jissa, VT; Tharakan, JA
    Thrombotic risk factors may contribute to premature coronary artery disease (CAD), in addition to the conventional risk factors. There is paucity of data on studies evaluating the role of thrombotic factors in premature CAD in Indian patients. Thus a case–control study was performed to evaluate the role of thrombotic and atherogenic factors in young patients with angiographically proven CAD who are on treatment with statins and antiplatelet drugs. 152 patients (B55 years) with angiographically proven CAD and 102 asymptomatic controls were recruited. Clinical and biochemical data were obtained in both groups. Blood levels of thrombotic factors-fibrinogen, antithrombin-III, tissue-plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1), von-Willebrand factor (v-WF), lipoprotein(a) [Lp(a)] and homocysteine were analyzed. Patients had high levels of conventional CAD risk factors (diabetes mellitus, smoking, hypertension, dyslipidemia and positive family history) compared to controls. Logistic regression analysis revealed that low antithrombin-III (odds ratio/OR 11.2; 95 % confidence interval/CI 2.29–54.01), high fibrinogen (OR 6.04; 95 % CI 1.09–33.21) and high Lp(a) (OR 4.54; 95 % CI 0.92–22.56), as important, independent risk factors in patients. PAI-1(OR 0.15; 95 % CI 0.03–0.69) levels were significantly lower in patients. But other thrombotic risk factors studied (t-PA, v-WF and homocysteine) were comparable among patients and controls. The treatment using statins and anti-platelet drugs might be contributing to the control of some of the thrombotic risk factors. The strategies aiming at lowering the levels of thrombotic risk factors along with conventional risk factors may be useful in primary and secondary prevention of CAD
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    Evidence for an exclusive association of matrix metalloproteinase-9 with dysfunctional high-density lipoprotein: A novel finding
    (Atherosclerosis, 2014-09) Sini, S; Deepa, D; Harikrishnan, S; Jayakumari, N
    OBJECTIVE: High-density lipoprotein is a heterogeneous class of lipoprotein with diverse antiatherogenic functions. However, these antiatherogenic properties of HDL can be compromised in atherosclerotic conditions. We have recently identified dysfunctionality in HDL even among healthy subjects, during systemic inflammation. This study was carried out with the objective of examining whether dysfunctional HDL is associated with pro-inflammatory proteins other than the acute phase proteins as reported earlier. METHODS: Serum HDL was isolated by three different methods-density gradient ultracentrifugation, PEG precipitation and electroelution. The antioxidant property of HDL was assessed as change in oxidation of LDL based on Dichloro-dihydro-fluorescein diacetate assay. HDL was subjected to gelatin zymography and western blot for assessment of MMP 9 activity. RESULTS: Dysfunctional HDL did not prevent the auto-oxidation of LDL. On the contrary the oxidation was enhanced. The zymogram data indicated enhanced MMP-9 activity selectively in dysfunctional HDL, irrespective of HDL isolation methods. This was confirmed by western blot of HDL probed with antibody specific to MMP 9. We also observed that dysfunctional HDL induced inflammatory response in monocyte/macrophages as evidenced by enhanced TNF-α and decreased IL-10 production. Further, invitro incubation of functional HDL with MMP-9 provided direct evidence for the association of MMP-9 with HDL and the role of MMP-9 in HDL dysfunction. CONCLUSION: A remarkable finding in the present study is the previously unrecognized association of MMP-9 with dysfunctional HDL and its proinflammatory property, indicating a novel molecular connection that can enhance the risk of cardiovascular disease in subjects with dysfunctional HDL.
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    Functionally defective high density lipoprotein is Pro-Oxidant: a Deviation from Normal Atheroprotective Character
    (International Journal of Nutrition and Food Sciences., 2013-02) Sini, S; Jayakumari, N
    High-density lipoprotein is a potential life saving antiatherogenic molecule. However, not all HDL is functionally similar, it can become dysfunctional and may increase atherosclerotic risk. At present, it is unknown, which structural alterations of HDL are essential accounting for its defective functionality and the precise pro-atherogenic mechanisms of action. This study is aimed at identification of the possible prevalence of dysfunctional HDL in subjects and its compositional and functional characterization in comparison to that of functional HDL. HDL was isolated from serum by ultracentrifugation and subjected to functional assays. HDL from majority of healthy subjects showed remarkable antioxidant property by inhibiting LDL oxidation. However, in those healthy subjects with systemic oxidative stress and inflammatory response as well as in those with known coronary heart disease, HDL was dysfunctional and promoted LDL oxidation. Dysfunctional HDL was truly pro-oxidant as it induced intracellular reactive oxygen species formation in cultured monocytes/macrophages. Functional deficiency in HDL did not show any association with HDL-cholesterol content. However, its characterization showed an enrichment of triglycerides, phospholipids, lipid peroxides, and diminished activity of paraoxonase-1, compared to functional HDL, which might render the particle dysfunctional and pro-oxidant.This study demonstrates the prevalence of dysfunctional HDL even among healthy subjects, despite normal HDL-C level, and in majority of subjects with known CHD, which is pro-oxidant in nature that might promote vascular inflammation and atherogenesis. The functional assay of HDL could lead to improved predictive accuracy of cardiovascular disease risk associated with circulating HDL.
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    IgA1 desialylated by microbial neuraminidase forms immune complex with naturally occurring anti-T antibody in human serum.
    (Immunology letters, 2008)
    IgA1 was identified as the most prominent O-glycosylated protein of human serum. Desialylation by bacterial (Clostridium perfringens) neuraminidase rendered dot-blotted IgA1 recognizable by the naturally occurring serum antibody (anti-T) directed against Thomsen-Friedenreich antigen, Galbeta1-->3GalNAc-alpha-. On Western blot of serum O-glycosylated proteins anti-T recognized nearly all the bands including IgA1 as did the T antigen-specific animal lectin galectin-1 but only after their desialylation. Agglutination of desialylated human erythrocytes by anti-T was effectively inhibited by desialylated IgA1, but not by native IgA1 or other immunoglobulins. Desialylation of serum by neuraminidase led to significantly increased formation of immune complexes containing IgM, the major immunoglobulin type in anti-T on one hand and O-glycosylated proteins/IgA1 on the other. In further evidence for anti-T-desialylated IgA1 immune complex formation, purified anti-T added to desialylated, but not native serum led to formation of additional IgA-IgM immune complexes. Also neuraminidase treatment significantly reduced the titre of free (non-immune complexed) anti-T in serum, while selective removal of anti-T by affinity absorption resulted in considerable decrease in the amount of IgA1 that got converted to immune complexes following enzymatic desialylation of serum. Formation of immune complex between anti-T and neuraminidase-treated IgA1 in serum may be significant since many disease pathogens release neuraminidase and since IgA1 is a powerful ligand for tissue galectin-1 more so after desialylation. Diabetes also raises serum IgA and neuraminidase levels.
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    Oxidative stress is increased in women with epilepsy: Is it a potential mechanism of anti-epileptic drug-induced teratogenesis
    (ANNALS OF INDIAN ACADEMY OF NEUROLOGY, 2012) Deepa, D; Jayakumari, N; Thomas, SV
    Context: Oxidative stress can be a final common pathway for AED-induced teratogenesis. Aims: To compare the oxidative stress of women with epilepsy (WWE) and unfavorable pregnancy outcome (fetal malformation or spontaneous abortion - group EM) with that of WWE with normal pregnancy outcome (group ENM) and healthy women with normal pregnancy outcome (group C). Materials and Methods: We identified WWE under group EM (n = 43) and group ENM (n = 22) from the Kerala Registry of Epilepsy and Pregnancy (KREP). Group C was constituted of healthy volunteers (N = 20). Oxidative stress was assessed by estimating serum levels of malondialdehyde (MDA) and isoprostane (ISP). The antioxidant profile was evaluated as activity of superoxide dismutase (SOD), glutathione reductase (GR), catalase (CAT), total antioxidant status (TAO), and glutathione (GSH) content. Results: The MDA and ISP levels for group EM (3.46 0.82 and 17.77 3.0) were higher than that of group ENM (3.07 1.02 and 14.0 5.3), and both were significantly higher than that of group C (2.42 0.51 and 10.77 4.1). Their levels of SOD (146.82 42.64 vs. 175.81 42.61) and GSH (0.98 0.98 vs. 1.55 1.3) were significantly lower than those of controls. No significant changes were seen in TAO and GR. WWE on polytherapy showed significant increase in MDA when compared to monotherapy group. Conclusion: WWE (group EM and ENM) had higher oxidative stress and reduced antioxidant activity. The subgroup of WWE with unfavorable pregnancy outcome (group EM) had higher oxidative stress. Excess oxidative stress can be a final common pathway, by which AEDs exert teratogenic effects.
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    Oxidized HDL Induces Cytotoxic Effects: Implications for Atherogenic Mechanism
    (Journal of biochemical and molecular toxicology, 2014-07) Soumyarani, VS; Jayakumari, N
    Atherosclerosis can be considered as an inflammatory disease and oxidized low-density lipoprotein (oxLDL) is a critical factor in atherogenesis. Although high-density lipoprotein (HDL) is generally an antiatherogenic lipoprotein, this property can be compromised by functional impairment mainly due to oxidative modification. As such, understanding the proatherogenic properties exerted by oxidized-HDL (oxHDL) becomes more important. This study was focused on examining the role of oxHDL as a proatherogenic agent, using oxLDL as a positive control. The comparative toxicity of oxHDL and oxLDL having same range of malondialdehyde, to monocytes was evaluated. After treatment, markers for oxidative stress, inflammation, and cytotoxicity were quantitated. The results showed that like oxLDL, oxHDL induced significant oxidative stress, cytotoxicity, and release of TNF -alpha and MMP-9 in monocytes/macrophages, but was less potent than oxLDL in promoting these proatherogenic effects. Further, the effects of oxHDL for the enhanced formation of MMP-9 were found to be mediated by NADPH oxidase/ROS-JNK/ERK pathway, as one mechanism.
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