Successful catheter ablation of ventricular tachycardia originating from the idiopathic saccular apical left ventricular aneurysm

Left ventricular (LV) aneurysm has been recognized to frequently become a substrate of ventricular tachyarrhythmias. We report a case of a 66-year-old woman with symptomatic sustained monomorphic ventricular tachycardia (SMVT) originating from saccular apical LV aneurysm without definite underlying diseases. We performed catheter ablation using electroanatomical and conventional bipolar potential mapping. During SMVT, we found an area of fragmented potential -40 ms preceding the earliest wide QRS complex in the area of the apical LV aneurysm. Radiofrequency applications were delivered to this area. Since then, SMVT was no longer inducible by programmed electrical stimulation. The patient has remained free of VT recurrences during a subsequent 12-month follow-up period.     

Tyrosines 559 and 807 in the cytoplasmic tail of the macrophage colony-stimulating factor receptor play distinct roles in osteoclast differentiation and function

Osteoclast (OC) differentiation requires that precursors, such as macrophage colony-stimulating factor (M-CSF)-dependent bone marrow macrophages, receive signals transduced by receptor activator of nuclear factor kappaB (RANK) and c-Fms, receptors for RANK ligand (RANKL) and M-CSF, respectively. Activated c-Fms autophosphorylates cytoplasmic tail tyrosine residues, which, by recruiting adaptor molecules, initiate specific signaling pathways. To identify which tyrosine residues are involved in c-Fms signaling in primary cells, we retrovirally transduced M-CSF-dependent bone marrow macrophages with a chimera comprising the external domain of the erythropoietin (Epo) receptor linked to the transmembrane and cytoplasmic domains of c-Fms. Transduced cells differentiate into bone-resorbing osteoclasts when treated with RANKL and either M-CSF or Epo, confirming that both endogenous and chimeric receptors transmit osteoclastogenic signals. Cells expressing chimeric receptors with Y(697)F, Y(706)F, Y(721)F, and Y(921)F single point mutations generate normal numbers of bone-resorbing OCs, with normal bone-resorbing activity when treated with RANKL and Epo. In contrast, those expressing Y(559)F generate fewer OCs, whereas theY807F mutant is incapable of osteoclastogenesis. Finally, although mature OCs expressing Y(559)F exhibit impaired bone resorption, those bearing Y807F do not. Thus, we have identified specific tyrosine residues in the cytoplasmic tail of c-Fms that are critical for transmitting M-CSF-initiated signals individually required for OC formation or function, respectively.     

Increased plasma levels of thioredoxin in patients with glucose intolerance

OBJECTIVE: The aim of the present study was to determine the effects of glucose intolerance on oxidative stress in patients with coronary artery disease (CAD). METHODS: The patients were divided into 3 groups, diabetes mellitus (DM), IGT or normal glucose tolerance (NGT) according to the criteria of the American Diabetes Association. PATIENTS: The present study consisted of 178 consecutive patients who underwent diagnostic coronary arteriography and a 75-g glucose tolerance test. RESULTS: The level of plasma thioredoxin, a marker of oxidative stress was measured in every patient during the fasting state. The levels of plasma thioredoxin were significantly higher in the DM and IGT groups than the NGT group. Furthermore, we found that there was a positive association between thioredoxin levels and glycosylated hemoglobin (sigma=0.225, p=0.018). In multivariate logistic regression analysis, glucose intolerance (DM or IGT) was only independently associated with the high levels of thioredoxin. The levels of plasma thioredoxin were significantly higher in the CAD group compared to the non-CAD group. In multivariate logistic regression analysis, high levels of thioredoxin, male, age and hypertension were independently associated with the presence of CAD. CONCLUSION: Glucose intolerance was associated with the high levels of thioredoxin. High levels of thioredoxin were related to the presence of CAD. The measurement of thioredoxin as the marker of oxidative stress may be useful for monitoring the development of the cardiovascular diseases.     

Ethanol Stimulates Immunoreactive Endothelin-1 and -2 Release from Cultured Human Umbilical Vein Endothelial Cells

The present study employed enzyme-immunoassay to examine the effect of ethanol on endothelin-1 and/or -2(ET1 + 2) release from human umbilical vein endothelial cells. Thirty minutes of exposure to ethanol increased the release of immunoreactive ET1 + 2 from cultured endothelial cells in a dose-dependent manner. However, ethanol at concentrations of less than 400 mM did not induce any LDH release from the endothelial cells. Trypan blue exclusion test revealed that 400 mM solution of ethanol decreased the cell viability to 7.7%. Thus, ethanol was found to directly stimulate ET1 + 2 release from cultured human umbilical vein endothelial cells. This reaction of vascular endothelial cells against ethanol may be related to ethanol-induced cardiovascular diseases such as hypertension, myocardial infarction and stroke, as well as fatal alcohol syndrome.     

Usefulness of hydrophilic vs lipophilic statins after acute myocardial infarction: subanalysis of MUSASHI-AMI.

BACKGROUND: Statins are widely used to reduce blood levels of low-density lipoprotein-cholesterol (LDL-C). Each statin has unique pharmacokinetic properties; lipophilicity is one such property and relates to tissue selectivity. METHODS AND RESULTS: The Multicenter Study for Aggressive Lipid-lowering Strategy by HMG-CoA Reductase Inhibitors in Patients with Acute Myocardial Infarction (MUSASHI-AMI) trial evaluated the effect of discretional statin treatment initiated within 96 h after onset of acute myocardial infarction (AMI) in Japanese patients. To clarify whether statin lipophilicity affects prognosis, a post hoc analysis of the MUSASHI-AMI database was performed. Patients who were assigned to receive statin were separated into 2 groups according to the lipophilicity of the statins they were administered: lipophilic statins (atorvastatin, fluvastatin, pitavastatin and simvastatin; LS group; n=131) or hydrophilic statins (pravastatin; HS group; n=110). There was no difference in baseline LDL-C concentrations between the 2 groups. Although LDL-C was decreased more potently in the LS than HS groups (-34% vs -19%; p=0.0069), acute coronary syndrome events tended to occur less frequently (3.6% vs 9.9%; p=0.0530) and the incidence of new Q-wave appearance in electrocardiogram was significantly lower (75% vs 89%; p=0.0056) in the HS than LS groups. CONCLUSIONS: In normocholesterolemic Japanese patients after AMI, hydrophilic pravastatin could be superior to lipophilic statins at preventing new Q-wave appearance and reducing cardiovascular events.     

Increased plasma thioredoxin in patients with acute myocardial infarction

BACKGROUND AND HYPOTHESIS: Thioredoxin is an important biomarker for oxidative stress. We investigated whether thioredoxin levels were elevated in patients with acute myocardial infarction (AMI) and were associated with the results of coronary reperfusion. METHODS: The present study determined plasma thioredoxin levels in 51 patients with AMI, 30 patients with stable exertional angina (SEA), and 30 patients with chest pain syndrome (CPS). Plasma sampling was performed on admission, at 12 h, 1 week, 2 weeks, and 4 weeks in patients with AMI, and after admission in patients with SEA and CPS. RESULTS: Plasma thioredoxin levels on admission were higher in patients with AMI than in those with SEA and CPS. Plasma thioredoxin levels in patients with AMI were decreased in 12 h without further change thereafter. However, thioredoxin levels in patients with AMI remained higher than in those with SEA. In multivariate analysis, higher levels of thioredoxin on admission were a risk factor for failure in emergent reperfusion therapy in patients with AMI independent of other factors. CONCLUSION: Plasma thioredoxin levels are elevated in patients with AMI, and higher thioredoxin levels may predict subsequent failed coronary reperfusion therapy in patients with AMI.     

Effect of ethanol on endothelin-1 release from gastric vasculature

The effects of ethanol on gastric vasculature in isolated vascularly perfused rabbit stomach was investigated. The isolated stomach was perfused with Krebs-Henseleit solution containing 3% dextran bubbled with 95% O₂ and 5% CO₂ at a rate of 12 ml/min. After mixture and perfusion of 10 mM to 400 mM of ethanol, perfusion pressure and endothelin-1 concentration in effluent from gastric vasculature were measured. Perfusion pressure and endothelin-1 concentration in effluent increased in a dose-dependent manner with increasing ethanol concentrations. In conclusion, the data suggest that ethanol may stimulate the release of endothelin from gastric vasculature and may cause gastric ischemia due to vasoconstriction resulting in acute gastric mucosal injury.