Roxanne Deslauriers

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Accurate quantitation of metabolites in biological samples of irregular shape and inhomogeneous composition is generally acknowledged to be difficult. The difficulties are less pronounced with a probe having excellent B1 field homogeneity, high sensitivity, and a resonant frequency independent of sample size and composition. A prototype probe that aims to(More)
BACKGROUND Antegrade and retrograde cerebral perfusion during hypothermic circulatory arrest (HCA) has been reported to provide better brain protection during operation than hypothermic circulatory arrest alone. However, the efficacy of these techniques remains to be fully determined, especially when used for prolonged periods. We used a pig model to(More)
The aim of this work was to investigate whether 1) Rb uptake is reduced in ischemic myocardium, and 2) 87Rb three-dimensional (3D) imaging can detect the ischemic area. Hearts of domestic pigs (n = 8, 20-30 kg) were perfused retrogradely with Krebs-Henseleit buffer in a 7-T, 40-cm horizontal bore magnet interfaced with Bruker MSLX spectrometer. Control (C)(More)
The aim of the study was to compare and analyze different noninvasive indices of cell damage in the isolated pig heart model of regional ischemia. We used (23)Na and (87)Rb MR imaging to evaluate Na(+)/K(+) balance, (31)P MR spectroscopy to measure energetics, and optical spectroscopy to assess oxymyoglobin (MbO(2)). Hearts were subjected to 120-min(More)
The rubidium efflux from hypothermic rat hearts perfused by the Langendorff method at 20 degreesC was studied. At this temperature 87Rb-NMR efflux experiments showed the existence of two 87Rb pools: cytoplasmic and mitochondrial. Rat heart mitochondria showed a very slow exchange of mitochondrial Rb+ for cytoplasmic K+. After washout of cytosolic Rb+,(More)
This study was designed to assess the effects of simultaneous antegrade/retrograde cardioplegia (SARC) on myocardial perfusion and energy metabolism in the region supported by the occluded left anterior descending artery (LAD) in isolated pig hearts. It was found that injection of Gd-DTPA into the aorta during antegrade cardioplegia (AC) did not result in(More)
K(+) uptake rates were measured in the anterior (An) and posterior (Pos) LV walls of pig hearts before and after regional ischemia and reperfusion using Rb(+) as a K(+) congener and 3D (87)Rb NMR imaging and spectroscopy as detection methods. The hearts were perfused by the Langendorff method with Krebs-Henseleit (KH) buffer and loaded with Rb(+) (4.7 mM,(More)
OBJECTIVE Continuous antegrade perfusion (AP) may interfere with surgical precision. Continuous retrograde perfusion (RP), on the other hand, cannot sustain the empty-beating hypertrophied hearts. Therefore, alternate antegrade/retrograde perfusion (A(A/R)P) may be a rational technique to preserve the hypertrophied hearts. This study is to determine whether(More)
A simple method has been developed for phasing 31P spectroscopic images acquired with short echo-time (1-2 ms) spin-echo sequences. The technique is based on reconstructing complete echoes in the time domain by the reversal of the complex conjugate of the data. After Fourier analysis, a magnitude reconstruction is used, which no longer broadens the lines.(More)
Trabeculae isolated from human atrial appendages have been used to study preservation of donor hearts for cardiac transplantation. We have developed a perifusion system equipped with a fiber optic strain gauge to study mechanical performance of human atrial trabeculae (10-20 mg) while simultaneously observing the energetic compounds by 31P NMR spectroscopy.(More)