Abstract
Background
We previously reported that pulmonary capillary wedge pressure (PCWP) was noninvasively evaluated by 2D speckle tracking echocardiography (STE). Recently, novel software was ...introduced to examine volume and function of left ventricular and left atrium (LA) by 3D-STE automatically.
Purpose
We sought to compare the PCWP estimated by conventional 2D-STE (2D-ePCWP) and by novel 3D-STE (3D-ePCWP), and validate those values by cardiac catheterization.
Methods
Echocardiography and catheterization were performed in 29 patients (age 72±2) (7 ischemic heart disease, 2 hypertensive heart disease, 5 dilated cardiomyopathy, 12 valvular heart disease and 3 primary pulmonary hypertension).The ePCWP (mmHg) is noninvasively obtained as 10.8 − 12.4 x Log (left atrial active emptying function/minimum volume) as we previously reported. Echocardiography was performed just before the catheterization and we analyzed the 2D and 3D data by novel off-line software. 3D data was automatically analyzed and the border settings were fixed at default (ES60, ED30) (Figure).
Results
2D-ePCWP and 3D-ePCWP had a good correlation with PCWP invasively obtained by catheterization (r=0.87 and 0.83, respectively, both p<0.001). There was an excellent correlation between 2D-ePCWP and 3D-ePCWP (r=0.94, p<0.001) and there was a good correlation between 2D-LA volume index and 3D- LA volume index (r=0.80, p<0.001). Bland-Altman analysis revealed a good agreement between 2D-ePCWP and 3D-ePCWP, and between 2D-ePCWP and 3D-ePCWP without fixed and proportional bias.
Conclusion
This study demonstrated that PCWP might be noninvasively assessed by not only 2D-STE but also 3D-STE with reasonable accuracy and 3D-STE might have utility and value in the routine clinical practice.
Abstract
Background
Left ventricular (LV) diastolic function is mainly composed of LV relaxation and LV stiffness. We reported that pulmonary capillary wedge pressure (ePCWP) and LV relaxation ...assessed by Tau (eTau) are noninvasively evaluated by speckle tracking echocardiography (STE). The minimum LV diastolic pressure (mLVP) was reported to have a strong correlation with Tau. Therefore, LV chamber stiffness (c-stiffness) may be assessed with the use of two LV diastolic pressure-volume coordinates: the mLVP and volume and the end-diastolic pressure (EDP) and volume.
Purpose
We sought to noninvasively assess LV stiffness using STE and validate the value by cardiac catheterization.
Methods
Echocardiography and catheterization were performed in 124 patients (age 72±8) (70 angina pectoris, 20 prior myocardial infarction, 19 hypertensive heart disease, 11 congestive heart failure and 4 paroxysmal atrial fibrillation). The ePCWP (mmHg) is noninvasively obtained as 10.8 − 12.4 × Log (left atrial active emptying function/minimum volume) and the eTau (ms) is obtained as isovolumic relaxation time/(ln 0.9 × systolic blood pressure − ln ePCWP) as previously reported. The mLVP (e-mLVP) was estimate using Tau. The estimated EDP (e-EDP) was calculated as 12.3 − 10.1 × Log (left atrial active emptying function / minimum volume). LV c-stiffness (mmHg/ml) was calculated as LV pressure change (from mLVP to EDP) obtained by catheterization divided by LV volume change during diastole which equals to stroke volume by echocardiography. Estimated c-stiffness (e-c-stiffness) was noninvasively obtained using e-mLVP and e-EDP. Furthermore, LV myocardial stiffness (m-stiffness) was calculated by LVED stress / LV longitudinal strain by STE, where LV stress (kdynes/cm2) was calculated as 0.334 × pressure × dimension / thickness (1 + thickness/dimension). The estimated m-stiffness (e-m-stiffness) was calculated using e-EDP.
Results
The eTau and e-EDP estimated by STE had a good correlation with Tau and EDP invasively obtained by catheterization (r=0.75 and 0.63, respectively, both p<0.001). There was a good correlation between Tau and mLVP (Tau = 2.06 mLVP + 33.7, r=0.70). The estimated LVED stress had good correlation with ED stress obtained by catheterization (r=0.77, p<0.001). The e-c-stiffness and e-m-stiffness had a good correlation with those obtained by catheterization (e-c-stiffness; 0.116±0.07 and c-stiffness; 0.115±0.06, r=0.603, e-m-stiffness; 0.81±0.41 and m-stiffness; 0.85±0.45, r=0.89, respectively). Bland-Altman analysis revealed a good agreement between e-c-stiffness and c-stiffness, and between e-m-stiffness and m-stiffness without fixed and proportional bias.
Conclusion
This study demonstrated that LV stiffness may be noninvasively assessed by STE with reasonable accuracy and may have utility and value in the routine clinical practice for the diagnosis and treatment in patients with diastolic dysfunction.
Abstract
Background
Left ventricular (LV) pressure-strain and pressure-volume (P-V) loop area reflect global myocardial work (MW) and stroke work (SW), but clinical use of these indexes is limited by ...the need of invasive pressure measurement. A noninvasive method to obtain LV pressure-strain loop area was recently introduced to examine MW by speckle tracking echocardiography (STE).
Purpose
We sought to evaluate the impact of preload change on MW and SW obtained using this novel method and to examine the utility to assess LV contractile performance by the SW and end-diastolic volume (EDV) relation (SW-VED) in patient with hemodialysis (HD).
Methods
LV pressure in a cardiac cycle was estimated using systolic blood pressure (SBP), LV minimum diastolic pressure (mDP) and end-diastolic pressure (EDP) in 20 HD patients (age 67±9)and 25 controls (age 67±9) by utilizing the profile of an empiric, normalized reference curve adjusted according to the duration of LV isovolumic and ejection phases as defined by timing of aortic and mitral valve events by echocardiography. Pulmonary capillary wedge pressure (ePCWP) is estimated as 10.8 – 12.4 × Log (left atrial active emptying function/minimum volume): KT index as previously reported. LVEDP were estimated as 12.3 – 10.1 × KT index. We examined the relation between LV pressure decline (Tau) and mDP by catheterization in 126 patients. Tau is estimated as isovolumic relaxation time/(ln 0.9 × systolic BP − ln ePCWP) as previously reported. SW was obtained by P-V loop area using the combination of pressure (SBP, mDP and EDP) and LV volume by 3D-STE. Echo parameters and BP were measured before and after HD and before and after leg up in controls.
Results
The mDP obtained by catheterization had a good correlation with Tau (Tau = 33.7 + 2.06 × mDP, r=0.70, p<0.01). LVEF by 3D-STE was increased in controls after leg up (59±5 to 62±4%) associated with increased LVEDV (85±25 to 91±26ml), whereas there was no difference in LVEF before and after HD (61±9 vs 61±10%) instead of decreased EDV after HD (101±23 to 92±24ml). SBP and PCWP in HD was decreased after HD (SBP: 149±25 to 140±15, PCWP: 9.8±4.3 to 8.5±3.6mmHg). MW and SW were increased after leg up in controls (1706±443 to 1972±461mmHg% and 4072±1938 to 5044±1958mmHgml) and those were decreased after HD (1964±441 to 1794±756mmHg% and 5475±1335 to 4722±1949mmHgml). LV SW-VEDin HD without LV dilation (EDVI<70ml/m2, n=12) was decreased compared to controls (143±115 vs 241±152) and that in HD with LV dilation was further decreased compared to HD without dilation.
Conclusion
LVSW noninvasively obtained by P-V loop area was increased in controls associated with increased preload and decreased in HD with decreased preload and SW-VED was deceased in HD. This novel and noninvasive method may be of potential utility to assess LV contractility and have a clinical interest and value to assess LV function.
► A fracture toughness test method was developed for a YBCO coated conductor with an additional Cu layer. ► Mode I type tests were carried out using double cantilever beam (DCB) specimens. ► ...Delamination propagated into the YBCO layer, and sometimes reached the Ag/YBCO interface. ► The fracture toughness for YBCO was about 10J/m2. ► That for Ag/YBCO interface was about 100J/m2.
Although interlaminar fracture at a YBa2Cu3O7−δ (YBCO)/CeO2 interface was reported for YBCO coated conductors, this has not yet been investigated by a fracture mechanical approach. In the present study, we developed a mode I type fracture toughness test method for a YBCO coated conductor with an additional Cu layer using double cantilever beam (DCB) specimens. Fracture mechanism was investigated by microscopic observation by a scanning electron microscope (SEM), together with composition analysis by an energy dispersive X-ray spectroscope (EDS). A pre-crack introduced at the YBCO/CeO2 interface deviated from the interface, and propagated into the YBCO layer, and sometimes reached the Ag/YBCO interface. The fracture toughness, GR, for YBCO and the Ag/YBCO interface was evaluated to be 7–10J/m2 and 80–120J/m2, respectively. The complex stress intensity factor ratio, K2/K1, at YBCO/CeO2 interface was evaluated to be −0.19, and this ratio controlled the formation of microcracks in the YBCO layer. The main crack propagated into the YBCO layer accompanied with the formation of microcracks.
Purpose
The purpose of this study was to investigate the risk of common peroneal nerve injury in FM drilling as compared to transtibial drilling in anatomical double-bundle ACL reconstruction.
...Methods
Ten cadaveric knees without ligament injury or significant arthritis were used for this study. Knees were secured at 90° and 120° of flexion. In transtibial drilling groups, a guide pin was drilled through either the anteromedial bundle (AMB) or posterolateral bundle (PLB) tibial insertion site to either the AMB or PLB femoral insertion site (tibial insertion site–femoral insertion site: AM–AM, PL–PL, PL-AM and AM–PL). In FM drilling groups (FM-AM and FM-PL),the pin was drilled at the AMB or PLB femoral insertion site through the FM. We measured the shortest distance between the point at which the pin ran through the lateral cortex of the femur and the ipsilateral common peroneal nerve at a knee flexion of 90° and 120°.
Results
At a knee flexion of 90°, the shortest mean distance to the common peroneal nerve was 15.3 mm in the FM-PL group, 13.4 mm in the FM-AM group, 27.9 mm in the PL–PL group, 30.8 mm in the AM–AM group, 37.8 mm in the PL–AM group and 29.5 mm in the AM–PL group. At a knee of flexion 120°, the mean distance was 17.3 mm in the FM-PL group, 18.1 mm in the FM-AM group, 32.2 mm in the PL–PL group, 36.6 mm in the AM–AM group, 38.0 mm in the PL–AM group and 35.2 mm in the AM–PL group. Significant differences were observed between 90° and 120° of knee flexion in the FM-AM, PL–PL, AM–AM and AM–PL groups (
P
< 0.05).Significant differences were observed at flex 90° between the FM-AM group and AM–AM group, and between the FM-AM group and PL–AM group. Significant differences were observed at flex 120° between the FM-AM group and AM–AM group, between the FM-AM group and PL–AM group and between the FM-PL group and AM–PL group.
Conclusion
The distance to the peroneal nerve in FM drilling was significantly longer at 120° than at 90° of knee flexion. Therefore, the risk of peroneal injury using FM drilling should decrease at a higher angle of knee flexion.
An Intersubunit Zinc Binding Site in Rat P2X2 Receptors Nagaya, Naomi; Tittle, Rachel K.; Saar, Nir ...
Journal of biological chemistry/The Journal of biological chemistry,
07/2005, Volume:
280, Issue:
28
Journal Article
Peer reviewed
Open access
P2X receptors are ATP-gated ion channels made up of three similar or identical subunits. It is unknown whether ligand binding is intersubunit or intrasubunit, either for agonists or for allosteric ...modulators. Zinc binds to rat P2X2 receptors and acts as an allosteric modulator, potentiating channel opening. To probe the location of this zinc binding site, P2X2 receptors bearing mutations of the histidines at positions 120 and 213 were expressed in Xenopus oocytes. Studies of H120C and H213C mutants produced five lines of evidence consistent with the hypothesis that the residues in these positions bind zinc. Mixing of subunits containing the H120A or H213A mutation generated receptors that showed zinc potentiation, even though neither of these mutant receptors showed zinc potentiation on its own. Furthermore, expression of trimeric concatamers with His → Ala mutations at some but not all six positions showed that zinc potentiation correlated with the number of intersubunit histidine pairs. These results indicate that zinc potentiation requires an interaction across a subunit interface. Expression of the H120C/H213C double mutant resulted in the formation of ectopic disulfide bonds that could be detected by changes in the physiological properties of the receptors after treatment with reducing and oxidizing agents. Immunoblot analysis of H120C/H213C protein separated under nonreducing conditions demonstrated that the ectopic bonds were between adjacent subunits. Taken together, these data indicate that His120 and His213 sit close to each other across the interface between subunits and are likely to be key components of the zinc binding site in P2X2 receptors.
...the purpose of this study was to investigate whether green tea consumption reverses endothelial dysfunction in association with improvement of oxidative stress in healthy smokers. Earlier studies ...have demonstrated that endothelial dysfunction is important in the pathogenesis and clinical manifestation of cardiovascular disease. ...green tea consumption may be beneficial for the prevention and treatment of atherosclerotic vascular disease.
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