11 research outputs found
Divergent molecular mechanisms for potassium channel remodeling in animal models of heart disease.
<p>AV, atrioventricular; ICM, ischemic cardiomyopathy; ND, not determined; -, no change.</p><p>*Weak bands limited the reliability of the measurement.</p>‡<p>KCNQ1.2, a truncated isoform of canine KCNQ1, was increased and may suppress I<sub>Ks</sub> in a dominant-negative fashion.</p
Comparison of waveforms between the Sham (2-d) and Infarct (2-d) groups after bolus injection of epinephrine.
<p>The only morphological differences in peri-infarct MAP were identified in the Infarct (2-d) group. (<b>A</b>) ECG Lead II waveforms showing that both groups had a comparable degree of heart rate increase. (<b>B</b>) MAP recorded at the peri-infarct epicardial zone showing that after the adrenergic challenge, the MAP of the Infarct (2-d) group had a dramatic shortening of MAPD30, whereas the MAPD90 was only minimally changed. (<b>C</b>) Direct overlapping of MAP showing that the MAP of the Infarct (2-d) group demonstrates more prominent triangulation.</p
Epicardial MAPD90/60/30 and triangulation (MAPD90 - MAPD30) recorded from the remote zone (basal).
<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0031545#s2" target="_blank">Results</a> were means ± STD. There were no significant differences between groups.</p
Ventricular tachycardia (VT), ventricular fibrillation (VF), and total premature ventricular beats (PVB) of the ischemia/reperfusion (IR)+L-768,673 and IR+vehicle groups.
<p>*All of the VTs and VFs occurred within 30 min of reperfusion.</p>‡<p>Animals that developed sustained VF were included in the analysis of VF, but were excluded from the analysis of other electrophysiological data.</p>§<p>Intervals 1, 2 and 3 were the interval from the initiation of reperfusion to R30, the interval from R30 to R75, and the interval from R75 to R120 respectively.</p><p>PVB data is expressed as median (25<sup>th</sup> percentile, 75<sup>th</sup> percentile). <sup>**</sup>P<0.05 vs. IR+vehicle. The median was increased by 4.6-fold in Group IR+L-768,673. No significant differences between VT, VF, total PVB, PVB in Interval 1 and PVB in Interval 3 were detected between the groups.</p
Comparison of epicardial monophasic action potential changes between groups.
<p>(<b>A</b>) Epicardial monophasic action potential durations (MAPDs) and triangulation (MAPD90–MAPD30) recorded from the ischemia/reperfusion zone (apical) in the Sham+vehicle group and the ischemia/reperfusion (IR)+vehicle group. *P<0.05 vs. Sham+vehicle. (<b>B</b>) Epicardial MAPDs and triangulation recorded from the ischemia/reperfusion zone in the Sham+L-768,673 group and the IR+L-768,673 group. *P<0.05 vs. Sham+L-768,673.</p
The P value of main effects and interaction effects of I/R or sham operation and L-768,673 or vehicle on MAPD and triangulation.
<p>I/R = Ischemia/reperfusion, interaction = interaction effect of ischemia/reperfusion and L-768,673, Triangulation = MAPD90–MAPD30.</p><p>P<0.05 highlighted by *.</p
Comparison of ventricular premature beats and KCNQ1 expression between groups.
<p>(<b>A</b>) Comparison of the total premature ventricular beats (PVBs) between the groups within 10 min after bolus injection of epinephrine. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0031545#s2" target="_blank">Results</a> are presented in a box plot format (n = 6–8) where boxes indicate the 25–75% interval along with the median of the data. * P<0.05 vs. the other groups. (<b>B</b>) Reverse transcription-polymerase chain reaction (RT-PCR) of KCNQ1 mRNA levels. Top: Examples of KCNQ1 mRNA with samples harvested from the peri-infarct zone and remote zone of the Healing (2-d; n = 6), Infarct (2-d; n = 8), Sham (2-d; n = 7), Healing (5-d; n = 7), Infarct (5-d; n = 7), and Sham (5-d; n = 8) groups of rabbit hearts. Bottom: mean KCNQ1 mRNA band intensities. (<b>C</b>) Western blot analysis of membrane-associated KCNQ1 protein levels. Top: Representative immunoblot results showing membrane KCNQ1 protein (∼75 kDa) with samples harvested from the peri-infarct zone and remote zone of the six groups of rabbit hearts. Bottom: mean membrane KCNQ1 protein band intensities. * P<0.05 vs. Sham (2-d) and Sham (5-d) respectively; # P<0.05 vs. Healing (2-d) and Healing (5-d) respectively; $ P<0.05 vs. Infarct (5-d).</p
Study protocol 1 of experiments.
<p>Monophasic action potentials were recorded after the equilibration at both the middle of the infarct zone and the unaffected zone of the epicardium. For L-768,673, The infusion rate of the initial dose was 0.5 µg/kg/h for 30 min, and the maintenance rate was 0.25 µg/kg/h for two hours. MAP duration data were expressed as MAPD90/60/30<sub>Baseline, Initial Dose, I5, I10, I15, I20, R5, R10, R15, R20, R25, R30, R45, R60, R75, R90, R105, R120</sub>, which stood for MAPD90/60/30 recorded at baseline, after initial dose, at ischemia for 5 min, 10 min, 15 min, 20 min and at reperfusion for 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, 45 min, 60 min, 75 min, 90 min, 105 min, 120 min, respectively.</p
MAPDs, triangulations and MAP waveforms comparison between the IR+L-768,673 and IR+vehicle groups.
<p>(<b>A</b>) Epicardial MAPDs and triangulation recorded from the ischemia/reperfusion zone (apical) in the IR+L-768,673 group and the IR+vehicle group. Triangulations of the IR+L-768,673 group were increased compared with those of the IR+vehicle group by 31.1%, 26.5%, and 19.3% at R45, R60, and R75 respectively. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0031545#s2" target="_blank">Results</a> are mean ± standard deviation (STD). * P<0.05 vs. IR+vehicle. (<b>B</b>) Comparison of monophasic action potential (MAP) waveforms between the IR+L-768,673 and IR+vehicle groups at R45, R60, and R75.</p