-
[show abstract]
[hide abstract]
ABSTRACT: PURPOSE: Effective intraprocedural anticoagulation for catheter ablation for atrial fibrillation is critical to minimize the risk of cerebral thromboembolism. The effect of dabigatran on anticoagulation with heparin during the procedure is unknown. This study compares heparin anticoagulation in patients treated with dabigatran vs. patients on uninterrupted warfarin. METHODS: Seventy-six consecutive patients (24 dabigatran and 52 warfarin) subjected to a standard intraprocedural heparin protocol were included. Heparin administration and rapidity and degree of anticoagulation were compared between the groups. RESULTS: Despite greater administration of heparin (52.5 ± 22.0 vs. 33.2 ± 10.1 units kg(-1) h(-1); p < 0.001), the mean (320.3 ± 19.5 s) and peak (358.8 ± 28.6 s) activated clotting time (ACT) for the dabigatran group were significantly lower than for the warfarin group (mean, 362.9 ± 35.9 and peak, 410.4 ± 49.7; p < 0.001). The time from initial heparin bolus to first ACT of ≥300 s in the dabigatran group was more than twice that observed in the warfarin group (45.0 ± 30.4 vs. 20.9 ± 14.5 min; p < 0.001). The time to first ACT of ≥350 s was similarly prolonged (109.1 ± 60.0 vs. 55.2 ± 51.1 min; p < 0.001) in the dabigatran group, with eight patients (33 %) failing to reach this target. Outcome differences persisted following analysis using linear models and Cox proportional hazard regression with adjustment for propensity scores. CONCLUSION: A standard intraprocedural heparin protocol results in delayed and lower levels of anticoagulation as measured by the ACT for patients treated with dabigatran compared with those on uninterrupted warfarin.
Journal of Interventional Cardiac Electrophysiology 09/2012; · 1.17 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Two exceedingly stable [Ru(bipy)(3)](3+) reagents were prepared by dissolving either [Ru(bipy)(3)](ClO(4))(2) in acetonitrile (containing 0.05 M HClO(4)) or [Ru(bipy)(3)]Cl(2)·6H(2)O in 95:5 glacial acetic acid-acetic anhydride (containing 0.05 M H(2)SO(4)) followed by oxidation with PbO(2). These conveniently prepared solutions provide highly reproducible chemiluminescence detection over long periods of analysis, avoiding the need for recalibration or preparation of fresh reagent solutions and without the complications associated with online chemical or electrochemical oxidations. The reagent prepared in acetonitrile produced much greater signal intensities with a range of analytes and was deemed most suitable for high-performance liquid chromatography (HPLC) with postcolumn chemiluminescence detection.
Analytical Chemistry 06/2011; 83(13):5453-7. · 5.86 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Unlike many other metal and metalloid ions, tin(II) elicits intense, analytically useful chemiluminescence upon reaction with tris(2,2'-bipyridyl)ruthenium(III) in acidic aqueous solution. This finding provides new insight into the nature of this widely used reagent and has enabled the first direct, selective determination of a metal ion with tris(2,2'-bipyridyl)ruthenium(III).
The Analyst 12/2009; 134(12):2397-9. · 4.23 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This paper describes, for the first time, a simple and effective synthetic route for covalently bonding the chemiluminescence reagent, (4-[4-(dichloromethylsilanyl)-butyl]-4Amethyl -2,2A-bipyridyl)bis(2,2A-bipyridyl)ruthenium(II) onto silica particles. The subsequent preparation of chemically regeneratable detection cells and their preliminary analytical evaluation with both sequential injection analysis and flow injection analysis are also reported. Unoptimised analytical figures of merit were established for standard solutions of codeine and sodium oxalate with detection limits calculated from three times the standard deviation of the blank signal, of 1 3 10 28 M and 3 3 10 27 M respectively. The chemically immobilised reagent exhibited some intriguing solvent and kinetic effects, which are also briefly discussed
05/2002;
-
[show abstract]
[hide abstract]
ABSTRACT: This paper describes, for the first time, a simple and effective synthetic route for covalently bonding the chemiluminescence reagent, (4-[4-(dichloromethylsilanyl)-butyl]-4'-methyl-2,2'-bipyridyl)bis(2,2'-bipyridyl)ruthenium(II) onto silica particles. The subsequent preparation of chemically regeneratable detection cells and their preliminary analytical evaluation with both sequential injection analysis and flow injection analysis are also reported. Unoptimised analytical figures of merit were established for standard solutions of codeine and sodium oxalate with detection limits calculated from three times the standard deviation of the blank signal, of 1 x 10(-8) M and 3 x 10(-7) M respectively. The chemically immobilised reagent exhibited some intriguing solvent and kinetic effects, which are also briefly discussed.
The Analyst 05/2002; 127(4):455-8. · 4.23 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Methodology based on high performance liquid chromatography (HPLC) has been developed for the determination of trace-metals in concentrated brines. Metal ions, (Al, Ba, Ca, Mg, Sr and Zn) were concentrated quantitatively and isolated from the sodium chloride matrix using a chelating ion-exchange column dynamically coated with the chelating dye xylenol orange. The pH dependence of the uptake of the metals was studied. Using the chelating ion-exchange preconcentration column followed by ion chromatography all the metals studied were determined at the low ng ml–1 level in concentrated brines and linear/workable calibrations were obtained in the concentration range of interest (–1). The methodology developed was successfully transferred to an automated on-line monitoring system for the determination of Ba, Ca, Mg and Sr in concentrated feed brines used in the chlor-alkali industry.
Microchimica Acta 12/1990; 104(1):39-47. · 3.03 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A new method for producing solutions of tris(2,2′-bipyridyl)ruthenium(III) ([Ru(bipy)3]3+) which have significantly improved stability over other methods is presented and preliminary analytical evaluation of the reagent for chemiluminescence is reported. The synthesis of anhydrous tris(2,2′-bipyridyl)ruthenium(III) perchlorate ([Ru(bipy)3](ClO4)3) salt is described and the use of acetonitrile as solvent to minimise the presence of water which can be oxidised by [Ru(bipy)3]3+, which causes the inherent instability. The stability of the new reagent in acetonitrile was monitored spectrophotometrically (λmax∼674 nm) and a decrease of <6% was observed. A flow injection analysis experiment was conducted using codeine to generate chemiluminescence to quantify the stability of the new reagent over 50 h. The results show a decrease in the chemiluminescence signal of <8%, which is a considerable improvement over previous methods.
Analytica Chimica Acta.
-
[show abstract]
[hide abstract]
ABSTRACT: Semi-automated flow injection instrumentation, incorporating a small anion exchange column coupled with tris(2,2′-bipyridyl)ruthenium(II) (Ru(bipy)32+) chemiluminescence detection, was configured and utilised to develop rapid methodology for the determination of sodium oxalate in Bayer liquors. The elimination of both negative and positive interferences from aluminium(III) and, as yet, unknown concomitant organic species, respectively are discussed. The robustness of the methodology was considerably enhanced by using the temporally stable form of the chemiluminescence reagent, tris(2,2′-bipyridyl)ruthenium(III) perchlorate in dry acetonitrile. Real Bayer process samples were analysed and the results obtained compared well with those performed using standard methods within industrial laboratories.
Analytica Chimica Acta. 458(2):291-296.
