[Unusual echo-free space behind the left atrium].
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Adult↗
Biomedical subjects
Yoko Eto
Publications and source records attributed to Yoko Eto.
Automated mitral annular tracking: a novel method for evaluating mitral annular motion using two-dimensional echocardiography.
We developed an automated mitral annular tracking method based on a digital processing of high frame rate cineloop images of 2-dimensional echocardiography. In this study, its feasibility and accuracy was validated in 11 healthy volunteers and 16 patients with left ventricular (LV) dysfunction. The mitral annular excursion measured by automated mitral annular tracking agreed well with that measured by 3-dimensional echocardiography and correlated with LV ejection fraction. The longitudinal mitral annular excursion was reduced whereas the radial one was preserved for patients with LV dysfunction compared with control subjects. The novel automated mitral annular tracking method is clinically feasible and has potential capability to quantify the comprehensive mitral annular motion for evaluating LV function in a clinical setting.
Adult↗
Repression of IFN-gamma expression by peroxisome proliferator-activated receptor gamma.
Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors expressed in a wide variety of cells. Our studies and others have demonstrated that both human and murine T cells express PPARgamma and that expression can be augmented over time in mitogen-activated splenocytes. PPARgamma ligands decrease proliferation and IL-2 production, and induce apoptosis in both B and T cells. PPARgamma ligands have also been shown to be anti-inflammatory in multiple models of inflammatory disease. In the following study, we demonstrate for the first time that PPARgamma is expressed in both murine CD4 and CD8 cells and that PPARgamma ligands directly decrease IFN-gamma expression by murine and transformed T cell lines. Unexpectedly, GW9662, a PPARgamma antagonist, increases lymphocyte IFN-gamma expression. Transient transfection studies reveal that PPARgamma ligands, in a PPARgamma-dependent manner, potently repress an IFN-gamma promoter construct. Repression localizes to the distal conserved sequence of the IFN-gamma promoter. Our studies also demonstrate that PPARgamma acts on the IFN-gamma promoter by interfering with c-Jun activation. These studies suggest that many of the observed anti-inflammatory effects of PPARgamma ligands may be related to direct inhibition of IFN-gamma by PPARgamma.
Animals↗
Early aerobic training increases end-tidal CO2 pressure during exercise in patients after acute myocardial infarction.
BACKGROUND: End-tidal CO2 partial pressure (PETCO2) has been suggested as a noninvasive index reflecting cardiac output under constant ventilation. The aim of this study was to examine whether PETCO2 does reflect cardiac output, even during exercise, in patients with acute myocardial infarction (AMI) undergoing exercise training early after onset. Method and Results Patients aged 47-73 years were randomly assigned to either a training group (n=18) or a control group (n=18) 1 week after the onset of AMI. Those in the training group performed exercise training under supervision at the anaerobic threshold level for 2 weeks, while patients in the control group followed a conventional walking regimen. In the training group, but not in the control group, PETCO2 at the respiratory compensation point increased significantly from 39.1+/-3.5 to 41.1+/-3.7 mmHg (p<0.01). Similarly, the cardiac index at peak exercise increased only in the training group (from 6.04+/-0.98 to 7.31+/-0.97 L/min per m2, p<0.01). These 2 measurements correlated well both before and after the study period. Peak oxygen uptake and anaerobic threshold were increased only in the training group. Conclusions Aerobic exercise training early after the onset of AMI significantly increased PETCO2 during exercise, which may reflect an improvement in cardiac output during exercise in response to physical training via a decreased ventilation-perfusion mismatch.
Adult↗
False-positive exercise echocardiograms: impact of sex and blood pressure response.
BACKGROUND: Factors related to false-positive results of exercise echocardiography (ExE) to diagnose coronary disease have not been extensively studied. In addition, previous studies were performed before routine use of digital and tissue harmonic imaging. We evaluated the clinical and echocardiographic predictors of false-positive results during ExE. METHODS: Four hundred sixty-four patients who had both coronary angiography and ExE were enrolled retrospectively. Significant coronary disease was defined by stenoses > or =50% lumen diameter. RESULTS: Fifty-eight (13%) had false-positive results. Thirty-one (53%) of these patients were women, which was significantly higher than the percentage of women (25%) in the true-positive group (P <.001). Average peak systolic blood pressure (BP) in the false-positive group was significantly higher than in the true-positive group. Test specificity was decreased at higher levels of BP without change of sensitivity. Men demonstrated a decrease in specificity at peak systolic BP > or =200 mm Hg, whereas women showed a sharp decrease in specificity at BP > or =180 mm Hg. Wall motion score index (WMSI) after peak exercise and the proportion of high- and intermediate-risk patients according to Duke score were significantly lower in the false-positive than in the true-positive group. CONCLUSIONS: The factors predictive of false-positive results during ExE to diagnose coronary disease were female sex, higher BP at peak exercise, lower risk by Duke score and lower number of abnormal segments and wall motion score index after peak exercise. Women appear to be susceptible to wall motion abnormalities caused by elevated exercise BP. These variables should be considered in the interpretation of ExE.
Adult↗
Pulmonary venous flow determinants of left atrial pressure under different loading conditions in a chronic animal model with mitral regurgitation.
BACKGROUND: The aim of our study was to quantitatively compare the changes and correlations between pulmonary venous flow variables and mean left atrial pressure (mLAP) under different loading conditions in animals with chronic mitral regurgitation (MR) and without MR. METHODS: A total of 85 hemodynamic conditions were studied in 22 sheep, 12 without MR as control (NO-MR group) and 10 with MR (MR group). We obtained pulmonary venous flow systolic velocity (Sv) and diastolic velocity (Dv), Sv and Dv time integrals, their ratios (Sv/Dv and Sv/Dv time integral), mLAP, left ventricular end-diastolic pressure, and MR stroke volume. We also measured left atrial a, x, v, and y pressures and calculated the difference between v and y pressures. RESULTS: Average MR stroke volume was 10.6 +/- 4.3 mL/beat. There were good correlations between Sv (r = -0.64 and r = -0.59, P <.01), Sv/Dv (r = -0.62 and r = -0.74, P <.01), and mLAP in the MR and NO-MR groups, respectively. Correlations were also observed between Dv time integral (r = 0.61 and r = 0.57, P <.01) and left ventricular end-diastolic pressure in the MR and NO-MR groups. In velocity variables, Sv (r = -0.79, P <.001) was the best predictor of mLAP in both groups. The sensitivity and specificity of Sv = 0 in predicting mLAP 15 mm Hg or greater were 86% and 85%, respectively. CONCLUSION: Pulmonary venous flow variables correlated well with mLAP under altered loading conditions in the MR and NO-MR groups. They may be applied clinically as substitutes for invasively acquired indexes of mLAP to assess left atrial and left ventricular functional status.
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