Browsing by Author "George, R"

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    Enhanced P-selectin expression on platelet-a marker of platelet activation, in young patients with angiographically proven coronary artery disease
    (MOLECULAR AND CELLULAR BIOCHEMISTRY, 2016) George, R; Bhatt, A; Narayani, J; Thulaseedharan, JV; Sivadasanpillai, H; Tharakan, JA
    P-selectin (CD62p) exposure is an established marker for platelet activation. P-selectin exposure can trigger variety of thrombotic and inflammatory reactions. In patients with coronary artery disease (CAD), platelets are activated, and hence, there is increased P-selectin exposure. The role of P-selectin exposure in patients on treatment with statins and anti-platelets is conflicting. A case-control study was performed to determine P-selectin exposure in consecutively recruited 142 patients (age aecurrency sign 55 years) with angiographically proven CAD on treatment and 92 asymptomatic controls. P-selectin exposure was determined by flow cytometry. Data on conventional risk factors were obtained along with estimation of levels of thrombotic [fibrinogen, lipoprotein (a), tissue plasminogen activator, plasminogen activator inhibitor-1, homocysteine and von Willebrand factor] and anti-thrombotic factors (antithrombin III). The P-selectin exposure was compared among patient groups who had different modes of presentation of CAD and categories of CAD disease severity. The patients were followed up for a period of 26 months. The results indicate that P-selectin exposure was significantly elevated in patients (mean +/- SD 9.24 +/- 11.81) compared to controls (mean +/- SD 1.48 +/- 2.85) with p < 0.0001. Similarly, conventional risk factors were significantly elevated in patients. P-selectin exposure showed significant negative correlation with antithrombin III levels. P-selectin exposure was higher in patients who presented with acute coronary syndromes than those who presented with effort angina. Cardiovascular event rate was 6 % on follow-up. The study establishes that thrombotic-inflammatory pathways enhancing P-selectin exposure unrelated to treatment might be activated in patients, while the event rate remained lowered, and hence, treatment strategies should be inclusive to control these factors.
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    Simultaneous determination of homocysteine and asymmetric dimethylarginine in human urine by liquid chromatography-tandem mass spectrometry
    (JOURNAL OF CHROMATOGRAPHY B-ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES, 2013) Gopu, CL; Hari, PR; George, R; Harikrishnan, S; Sreenivasan, K
    Increased circulating concentrations of homocysteine (HCY) and asymmetric dimethylarginine (ADMA) are associated with vascular disease and vascular risk factors. HCY has been shown to inhibit the activity of endothelial dimethylaminohydrolase (DDAH), causing the accumulation of ADMA and the inhibition of nitric oxide synthesis. The concentrations of HCY and ADMA in biological fluids are used in the clinical diagnosis of cardiovascular diseases and this necessitates the development of a rapid and sensitive method for simultaneous determination of HCY and ADMA. A rapid, simple and sensitive method for simultaneous determination of HCY and ADMA by liquid chromatography-tandem mass spectrometry (LC-MS/MS) coupled with electro spray ionization (ESI) in human urine was reported here. The methodology designed here was used to estimate these molecules in urine samples collected from patients reported to Cardiology Department of our hospital. Chromatographic separation was performed on Atlantis HILIC silica (100 mm x 2.1 mm, 5 mu m, Waters). Positive multiple reactions monitoring (MRM) mode was chosen for quantification of each analyte and cystamine dihydrochloride (CYA) was used as the internal standard (IS) for the assay. The intra-assay precision and accuracy were in the range of 2.4-4.8 and -1.8% to 3.1%, respectively. The inter-assay precision and accuracy were in the range of 3.0-4.2% and -1.2% to 3.2%, respectively. The recoveries were between 94.9% and 101.4%. Our approach is simple, rapid and could be extended to routine urine assay. (C) 2013 Elsevier B.V. All rights reserved.
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    Simultaneous determination of homocysteine and asymmetric dimethylarginine in human urine by liquid chromatography–tandem mass spectrometry
    (J. Chromatogr B., 2013-10) Gopu, GL; Hari, PR; George, R; Harikrishnan, S; Sreenivasan, K