Comparison of episodes of ventricular tachycardia within 10 min of bolus injection of epinephrine.

<p>No significant differences were identified between the groups; however, the runs of ventricular tachycardia occurred exclusively in the 2-d infarct group.</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

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_Ks in a dominant-negative fashion.</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

Role of TRPM7 Channels in Hyperglycemia-Mediated Injury of Vascular Endothelial Cells

<div><p>This study investigated the change of transient receptor potential melastatin 7 (TRPM7) expression by high glucose and its role in hyperglycemia induced injury of vascular endothelial cells. Human umbilical vein endothelial cells (HUVECs) were incubated in the presence or absence of high concentrations of D-glucose (HG) for 72h. RT-PCR, Real-time PCR, Western blotting, Immunofluorescence staining and whole-cell patch-clamp recordings showed that TRPM7 mRNA, TRPM7 protein expression and TRPM7-like currents were increased in HUVECs following exposure to HG. In contrast to D-glucose, exposure of HUVECs to high concentrations of L-glucose had no effect. HG increased reactive oxygen species (ROS) generation, cytotoxicity and decreased endothelial nitric oxide synthase protein expression, which could be attenuated by knockdown of TRPM7 with TRPM7 siRNA. The protective effect of silencing TRPM7 against HG induced endothelial injury was abolished by U0126, an inhibitor of the extracellular signal-regulated kinase signaling pathway. These observations suggest that TRPM7 channels play an important role in hyperglycemia-induced injury of vascular endothelial cells.</p> </div

Study protocol 2 of experiments.

<p>Monophasic action potentials were recorded after the equilibration at both the peri-infarct zone and the unaffected zone of the epicardium during each open chest operation and at the time point of peak adrenergic excitation. MAP duration data were expressed as MAPD90/60/30_{pre-op, post-op, epi i.v.}, which stood for MAPD90/60/30 recorded at first operation, at second operation, and after the bolus intravenous injection of epinephrine, respectively.</p

Comparison of MAP data recorded at the peri-infarct zone and heart rate (HR) in animals subjected to ischemia and healing, infarction, or sham operation.

<p>Pre-op corresponds to data recorded at the first operation; post-op to data at the second operation; epi i.v. to data at the peak stimulation of epinephrine. Triangulation = MAPD90–MAPD30; MAPD90 shortening = MAPD90_post-op−MAPD90 _{epi i.v.}; HR, heart rate; adr, epinephrine; bpm, beats per minute; i.v., intravenous injection.</p><p>*P<0.05 vs. post-op;</p>#<p>P<0.05 vs. infarct (2-d).</p

Effect of TRPM7 siRNA on eNOS protein expression, NO and ROS generation in HG treated HUVECs.

<p>The cells were preincubated with TRPM7 siRNA or control siRNA for 48h, and then stimulated with HG for 72h. (A) Representative immunoblots showing eNOS protein expression level. (B) The corresponding bar graphs showing the relative expression of eNOS protein normalized to beta-actin. (C) The production of NO was determined by measurement of nitrite, a stable product of NO. (D) The production of intracellular ROS was assessed by the oxidation of 2’,7’-dichlorofluorescin diacetate to fluorescent 2’,7’-dichlorofluorescein. **<i>p</i><0.01 vs. control; ^##<i>p</i><0.01 vs. control siRNA. n=3 for immunoblotting , 5 for ROS generation assay and 6 for NO measurement.</p

Effect of HG on TRPM7 protein expression in HUVECs.

<p>(A) Representative immunoblots showing TRPM7 protein expression in HUVECs with or without HG (30 mM) for 72h. (B) The corresponding bar graphs showing relative expression of TRPM7 protein normalized to beta-actin. (C) Representative TRPM7-like currents recorded in HUVECs cultured in control or HG (30 mM) for 72h. (D) TRPM7-like current density. **<i>p</i><0.01 vs. HG; *<i>p</i><0.05 vs. control. n=4 for immunoblotting and 17-18 cells patched for current recording. </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