Characterization of glucan involved in the reduction of dental caries in rats.

Culture supernatant fluids (SF) of mutant 108 obtained from Streptococcus sobrinus 6715, when incubated with sucrose, produce large amounts of water-soluble glucans. Mainly, two water-soluble glucan synthesizing glucosyltransferases (GTases) were found in culture SF by isoelectric focusing. These two GTases had higher activities than those from the parent strain. The GTase which synthesizes water-insoluble glucan totally lacked the mutant. When the glucan preparation synthesized by the SF was subjected to gel filtration, a major large molecular weight fraction (designated glucan A) and a small molecular weight fraction (designated glucan B) were obtained. Glucan A yielded a smaller molecular weight glucan after treatment with dextranase. Glucan B was not hydrolyzed by the same enzyme.

Characterization of cross-reactive polysaccharide antigen with serotype a and d strains from Streptococcus sobrinus 6715.

The polysaccharide antigen (designated SI) from Streptococcus sobrinus 6715 (serotype g) which cross-reacts with serotype a and d strains was purified by a specific anti-cross-reactive g-a antibody-Sepharose 4B affinity column. By a double immunodiffusion analysis, the SI antigen was found to lack the serotype-specific g site, but contained the cross-reactive sites g-a, g-d and g-(a-d) on a single molecule. Polysaccharide SI was composed of galactose, glucose and rhamnose in a molar ratio of 4.79:1.52:1. The results of the test on the inhibition of the precipitin reaction and methylation analysis suggested that the cross-reactive site g-a of the SI antigen appeared to have two regions, one containing galactose residues and the other, beta-linked glucose residues.

The nature of the multiple forms of D-erythrodihydroneopterin triphosphate synthetase.

1. Three forms of the Lactobacillus plantarum enzyme D-erythro-dihydroneopterin triphosphate synthetase, the first enzyme in folate biosynthesis, have been demonstrated by polyacrylamide gel electrophoresis. The enzyme forms designated the alpha prime, alpha and beta forms have been shown to be conformers with molecular weights of approx. 200 000. Study of the subunit structure of the beta enzyme species by sodium dodecylsulfate-polyacrylamide gel electrophoresis revealed a single protein with an estimated molecular weight of 20 000 which suggests that the enzyme molecule may be composed of ten polypeptide chains. 2. Of the three conformers only one form, the beta form, appears to be enzymatically active. The two other conformers must undergo conformational changes to the beta species before enzymatic activity can be demonstrated in reaction mixtures containing these enzyme forms. 3. The three enzyme species are interconvertible. The removal of phosphate ions from the enzymatically active beta form results in the formation of two inactive species which suggests that the conformation of the active enzyme is stabilized by non-covalently bound phosphate ions. Conversion of the inactive species to the beta enzyme form may be effected by the readdition of phosphate, substrate or certain nucleotides.

Real-time three-dimensional echocardiographic study of left ventricular function after infarct exclusion surgery for ischemic cardiomyopathy.

BACKGROUND: Infarct exclusion (IE) surgery, a technique of left ventricular (LV) reconstruction for dyskinetic or akinetic LV segments in patients with ischemic cardiomyopathy, requires accurate volume quantification to determine the impact of surgery due to complicated geometric changes. METHODS AND RESULTS: Thirty patients who underwent IE (mean age 61+/-8 years, 73% men) had epicardial real-time 3-dimensional echocardiographic (RT3DE) studies performed before and after IE. RT3DE follow-up was performed transthoracically 42+/-67 days after surgery in 22 patients. Repeated measures ANOVA was used to compare the values before and after IE surgery and at follow-up. Significant decreases in LV end-diastolic (EDVI) and end-systolic (ESVI) volume indices were apparent immediately after IE and in follow-up (EDVI 99+/-40, 67+/-26, and 71+/-31 mL/m(2), respectively; ESVI 72+/-37, 40+/-21, and 42+/-22 mL/m(2), respectively; P:<0.05). LV ejection fraction increased significantly and remained higher (0.29+/-0.11, 0.43+/-0.13, and 0.42+/-0.09, respectively, P:<0.05). Forward stroke volume in 16 patients with preoperative mitral regurgitation significantly improved after IE and in follow-up (22+/-12, 53+/-24, and 58+/-21 mL, respectively, P:<0.005). New York Heart Association functional class at an average 285+/-144 days of clinical follow-up significantly improved from 3.0+/-0.8 to 1.8+/-0.8 (P:<0.0001). Smaller end-diastolic and end-systolic volumes measured with RT3DE immediately after IE were closely related to improvement in New York Heart Association functional class at clinical follow-up (Spearman's rho=0.58 and 0.60, respectively). CONCLUSIONS: RT3DE can be used to quantitatively assess changes in LV volume and function after complicated LV reconstruction. Decreased LV volume and increased ejection fraction imply a reduction in LV wall stress after IE surgery and are predictive of symptomatic improvement.

Current status of flow convergence for clinical applications: is it a leaning tower of "PISA"?

Spatial appreciation of flow velocities using Doppler color flow mapping has led to quantitative evaluation of the zone of flow convergence proximal to a regurgitant orifice. Based on the theory of conservation of mass, geometric analysis, assuming a series of hemispheric shells of increasing velocity as flow converges on the orifice--the so-called proximal isovelocity surface area (PISA) effect--has yielded methods promising noninvasive measurement of regurgitant flow rate. When combined with conventional Doppler ultrasound to measure orifice velocity, regurgitant orifice area, the major predictor of regurgitation severity, can also be estimated. The high temporal resolution of color M-mode can be used to evaluate dynamic changes in orifice area, as seen in many pathologic conditions, which enhances our appreciation of the pathophysiology of regurgitation. The PISA methodology is potentially applicable to any restrictive orifice and has gained some credibility in the quantitative evaluation of other valve pathology, particularly mitral and tricuspid regurgitation, and in congenital heart disease. Although the current limitations of PISA estimates of regurgitation have tempered its introduction as a valuable clinical tool, considerable efforts in in vitro and clinical research have improved our understanding of the problems and limitations of the PISA methodology and provided a firm platform for continuing research into the accurate quantitative assessment of valve regurgitation and the expanding clinical role of quantitative Doppler color flow mapping.

Doppler evaluation of severity of mitral regurgitation: relation to pulmonary venous blood flow patterns in an animal study.

OBJECTIVES: This study examined the influence of regurgitant volume on pulmonary venous blood flow patterns in an animal model with quantifiable mitral regurgitation. BACKGROUND: Systolic pulmonary venous blood flow is influenced by atrial filling and compliance and ventricular output and by the presence of mitral regurgitation. The quantitative severity of the regurgitant volume itself is difficult to judge in clinical examinations. METHODS: Six sheep with chronic mitral regurgitation produced by previous operation to create chordal damage were examined. At reoperation the heart was exposed and epicardial echocardiography performed. Pulmonary venous blood flow waveforms were recorded by pulsed Doppler under color flow Doppler guidance using a Vingmed 750 scanner. The pulmonary venous systolic inflow to the left atrium was expressed as a fraction of the total inflow velocity time integral. Flows across the aortic and mitral valves were recorded by electromagnetic flowmeters balanced against each other. Pressures in the left ventricle and left atrium were measured directly with high fidelity manometer-tipped catheters. Preload and afterload were systematically manipulated, resulting in 24 stable hemodynamic states. RESULTS: Simple logarithmic correlation between the regurgitant volume and size of a positive or negative pulmonary venous inflow velocity time integral during systole was good (r = -0.841). By stepwise linear regression analysis with pulmonary venous negative systolic velocity time integral as a dependent variable compared with the regurgitant volume, fractional shortening, left atrial v wave size, systemic vascular resistance and left ventricular systolic pressure, only contributions from v wave size and regurgitant volume (r = 0.80) reached statistical significance in determining pulmonary venous negative systolic flow. CONCLUSIONS: Evaluation of systolic pulmonary venous blood flow velocity time integral can give valuable information helpful for estimating the regurgitant volume secondary to mitral regurgitation.

Estimation of regurgitant flow volume based on centerline velocity/distance profiles using digital color M-Q Doppler: application to orifices of different shapes.

OBJECTIVES: In this study we investigated the centerline velocity profile method for flow computation as applied to noncircular, as well as circular, orifices using digital color flow data. BACKGROUND: Recently it has been suggested that flow volume through an orifice can be estimated more accurately by computing the axial "centerline" flow velocity/distance profile proximal to the orifice. METHODS: A total of seven different orifices were mounted in a constant-flow model: four circular orifices, two rectangular orifices with a major/minor axis ratio of 4:1 and 8:1 and an ovoid orifice having a major/minor axis ratio of 2:1. Three different flow rates were examined (1.68, 3.48 and 6.48 liters/min). Digital measurements of flow velocity at discrete positions along the centerline progressing toward the orifice were analyzed to yield complete flow velocity profiles for each orifice at each flow rate. RESULTS: A clear separation of the flow profiles for the three different flow rates was observed independent of orifice size for all of the circular orifices. The velocity/distance acceleration curves showed highly significant correlations using multiplicative regression fits (y = ax-b, r = 0.94 to 0.99, all p < 0.0001). An equation for quantitatively correlating the a and b coefficients from the multiplicative regression fits with flow rates was derived from stepwise regression analysis: Flow rate = 23a + 3.3b - 1.5 (r = 0.97, p < 0.0001, SEE 0.46 liter/min). CONCLUSIONS: In view of the various sizes and shapes encountered clinically for regurgitant orifices, the simplicity of this method for the estimation of the severity of regurgitant lesions might be of importance for clinical applications of this method.

Color Doppler regurgitant jet area for evaluating eccentric mitral regurgitation: an animal study with quantified mitral regurgitation.

OBJECTIVES: The purpose of the present study was to rigorously evaluate the accuracy of the color Doppler jet area planimetry method for quantifying chronic mitral regurgitation. BACKGROUND: Although the color Doppler jet area has been widely used clinically for evaluating the severity of mitral regurgitation, there have been no studies comparing the color jet area with a strictly quantifiable reference standard for determining regurgitant volume. METHODS: In six sheep with surgically produced chronic mitral regurgitation, 24 hemodynamically different states were obtained. Maximal color Doppler jet area for each state was obtained with a Vingmed 750. Image data were directly transferred in digital format to a microcomputer. Mitral regurgitation was quantified by the peak and mean regurgitant flow rates, regurgitant stroke volumes and regurgitant fractions determined using mitral and aortic electromagnetic flow probes. RESULTS: Mean regurgitant volumes varied from 0.19 to 2.4 liters/min (mean [+/- SD] 1.2 +/- 0.59), regurgitant stroke volumes from 1.8 to 29 ml/beat (mean 11 +/- 6.2), peak regurgitant volumes from 1.0 to 8.1 liters/min (mean 3.5 +/- 2.1) and regurgitant fractions from 8.0% to 54% (mean 29 +/- 12%). Twenty-two of 24 jets were eccentric. Simple linear regression analysis between maximal color jet areas and peak and mean regurgitant flow rates, regurgitant stroke volumes and regurgitant fractions showed correlation, with r = 0.68 (SEE 0.64 cm2), r = 0.63 (SEE 0.67 cm2), r = 0.63 (SEE 0.67 cm2) and r = 0.58 (SEE 0.71 cm2), respectively. Univariate regression comparing regurgitant jet area with cardiac output, stroke volume, systolic left ventricular pressure, pressure gradient, left ventricular/left atrial pressure gradient, left atrial mean pressure, left atrial v wave pressure, systemic vascular resistance and maximal jet velocity showed poor correlation (0.08 < r < 0.53, SEE > 0.76 cm2). CONCLUSIONS: This study demonstrates that color Doppler jet area has limited use for evaluating the severity of mitral regurgitation with eccentric jets.

Factors influencing pulmonary venous flow velocity patterns in mitral regurgitation: an in vitro study.

OBJECTIVES: The aim of this study was to investigate factors affecting pulmonary venous flow patterns in mitral regurgitation. BACKGROUND: Although pulmonary venous flow velocity patterns have been reported to be helpful in assessing the severity of mitral regurgitation, the influence of regurgitant jet direction, pulmonary venous location and left atrial pressures on pulmonary venous flow patterns has yet to be clarified. METHODS: The mitral regurgitant jet was produced by a pulsatile piston pump at 10, 30 and 40 ml/beat through a circular orifice, whereas the pulmonary venous flow was driven by gravity. Four different patterns of pulmonary venous flow and mitral regurgitation were examined. The V wave pressure was set at 10, 30 and 50 mm Hg and pulmonary venous flow velocity at 30 cm/s. Color and pulsed Doppler recordings were obtained with a VingMed 800 scanner interfaced with a computer facilitating digital analysis. RESULTS: The decrease in the velocity time integral of pulmonary venous flow was more prominent for any given volume of mitral regurgitation at higher left atrial pressure. When the mitral regurgitant jet was directed toward the pulmonary vein, a more prominent decrease in the velocity time integral was seen, especially for severe mitral regurgitation (40 ml) with high left atrial pressure (95% vs. 55%, p < 0.001); and the time to peak deceleration of forward flow was significantly shorter (485 vs. 523 ms, respectively, p < 0.01). Also, two different types (laminar and turbulent) of reversed pulmonary venous flow were observed. CONCLUSIONS: Multiple factors, including jet direction, mitral regurgitant volume and left atrial pressure, determine the effect of mitral regurgitation on pulmonary venous flow velocity patterns.

Dynamic change in mitral regurgitant orifice area: comparison of color Doppler echocardiographic and electromagnetic flowmeter-based methods in a chronic animal model.

OBJECTIVES: The aim of the present study was to investigate dynamic changes in the mitral regurgitant orifice using electromagnetic flow probes and flowmeters and the color Doppler flow convergence method. BACKGROUND: Methods for determining mitral regurgitant orifice areas have been described using flow convergence imaging with a hemispheric isovelocity surface assumption. However, the shape of flow convergence isovelocity surfaces depends on many factors that change during regurgitation. METHODS: In seven sheep with surgically created mitral regurgitation, 18 hemodynamic states were studied. The aliasing distances of flow convergence were measured at 10 sequential points using two ranges of aliasing velocities (0.20 to 0.32 and 0.56 to 0.72 m/s), and instantaneous flow rates were calculated using the hemispheric assumption. Instantaneous regurgitant areas were determined from the regurgitant flow rates obtained from both electromagnetic flowmeters and flow convergence divided by the corresponding continuous wave velocities. RESULTS: The regurgitant orifice sizes obtained using the electromagnetic flow method usually increased to maximal size in early to midsystole and then decreased in late systole. Patterns of dynamic changes in orifice area obtained by flow convergence were not the same as those delineated by the electromagnetic flow method. Time-averaged regurgitant orifice areas obtained by flow convergence using lower aliasing velocities overestimated the areas obtained by the electromagnetic flow method ([mean +/- SD] 0.27 +/- 0.14 vs. 0.12 +/- 0.06 cm2, p < 0.001), whereas flow convergence, using higher aliasing velocities, estimated the reference areas more reliably (0.15 +/- 0.06 cm2). CONCLUSIONS: The electromagnetic flow method studies uniformly demonstrated dynamic change in mitral regurgitant orifice area and suggested limitations of the flow convergence method.

Vena contracta imaged by Doppler color flow mapping predicts the severity of eccentric mitral regurgitation better than color jet area: a chronic animal study.

OBJECTIVES: This study sought to evaluate the relation between the color Doppler-imaged vena contracta and the severity of mitral regurgitation (MR) in a chronic animal model of MR. BACKGROUND: The vena contracta, which is defined as the smallest connection between the laminar flow acceleration zone and the turbulent regurgitant jet, has been reported to be a clinically useful marker for evaluating the severity of valvular regurgitation. METHODS: Six sheep with chronic MR produced by previous operation severing the chordae tendineae were examined. MR jet flows and vena contracta widths were imaged using a Vingmed 775 scanner with a 5-MHz transducer. Image data were directly transferred in digital format to a microcomputer for off-line measurement. MR was quantified as peak and mean regurgitant flow rates, regurgitant stroke volumes and regurgitant fractions determined using mitral and aortic electromagnetic flow probes and flowmeters balanced against each other. RESULTS: Vena contracta width correlated well with regurgitant severity determined by electromagnetic flowmeters (r = 0.95, SEE = 0.05 cm, p < 0.0001 for peak regurgitant flow rate; r = 0.85, SEE = 0.08 cm, p < 0.0001 for regurgitant stroke volume; r = 0.90, SEE = 0.07 cm, p < 0.0001 for regurgitant fraction). CONCLUSIONS: This study shows that the vena contracta width method is useful for predicting the severity of MR. It is simple and conveniently available with high resolution equipment. The quantitative comparisons in the present study lay the foundation for future clinical and research studies using this vena contracta technique.

Validation of the accuracy of both right and left ventricular outflow volume determinations and semiautomated calculation of shunt volumes through atrial septal defects by digital color Doppler flow mapping in a chronic animal model.

OBJECTIVES: The aim of the present study was to quantitate shunt flow volumes through atrial septal defects (ASDs) in a chronic animal model with surgically created ASDs using a new semiautomated color Doppler flow calculation method (ACM). BACKGROUND: Because pulsed Doppler is cumbersome and often inappropriate for color flow computation, new methods such as ACM are of interest. METHODS: In this study, 13 to 25 weeks after ASDs were surgically created in eight sheep, a total of 24 hemodynamic states were studied at a separate open chest experimental session. Electromagnetic (EM) flow probes and meters were used to provide reference flow volumes as the pulmonary and aortic flow volumes (Qp and Qs) and shunt flow volumes (Qp minus Qs). Epicardial echocardiographic studies were performed to image the left and right ventricular outflow tract (LVOT and RVOT) forward flow signals. The ACM method digitally integrated spatial and temporal color flow velocity data to provide stroke volumes. RESULTS Left ventricular outflow tract and RVOT flow volumes obtained by the ACM method agreed well with those obtained by the EM method (r = 0.96, mean difference = 0.78 +/- 1.7 ml for LVOT and r = 0.97, mean difference = -0.35 +/- 3.6 ml for RVOT). As a result, shunt flow volumes and Qp/Qs by the ACM method agreed well with those obtained by the EM method (r = 0.96, mean difference = -1.1 +/- 3.6 ml/beat for shunt volumes and r = 0.95, mean difference = -0.11 +/- 0.22 for Qp/Qs). CONCLUSIONS: This animal study, using strictly quantified shunt flow volumes, demonstrated that the ACM method can provide Qp/Qs and shunt measurements semiautomatically and noninvasively.

Effects of adjacent surfaces of different shapes on regurgitant jet sizes: an in vitro study using color Doppler imaging and laser-illuminated dye visualization.

OBJECTIVES: The present study was designed to estimate the influence of different-shaped adjacent surfaces on regurgitant jets as assessed by color Doppler imaging and laser-illuminated dye optical visualization. BACKGROUND: Because color Doppler techniques provide real-time two-dimensional imaging of flow, the evaluation of valvular regurgitation by analysis of variance-encoded regurgitant jets by this method has been widely used in clinical studies. However, recent studies have demonstrated that color Doppler jet sizes are affected not only by several hemodynamic factors and instrument settings but also by the interaction between jets and adjacent wall surfaces. In clinical conditions, jets may interact with adjacent walls of variable shapes that might have different effects on the jet size. METHODS: An in vitro model was constructed consisting of a rigid, optically clear receiving chamber that had no outlet resistance and had a pulsatile pump ejecting through 1.5, 2.3 and 3.1 mm2 inflow orifices into the chamber. The surfaces were flat or smoothly and equally curved, convex and concave aluminum positioned at 0, 2 and 4 mm from and to the side of the inflow orifices. The pump was run with stroke volumes from 0.5 to 3.0 ml and with a pulse frequency of 70 beats/min. The echocardiographic and laser beams were aimed at the inflow orifice imaging jets perpendicular to the surfaces (vertical view) through the central plane of the jet flows. Maximal jet areas were measured by both color Doppler techniques and laser-illuminated dye visualization. RESULTS: Color Doppler study showed fair correlation between the jet areas and the stroke volumes (r = 0.83 to 0.99), but the jet sizes under different surface conditions were variable. All the surface jet areas at a jet-surface distance of 0 and 2 mm were smaller than free jet areas at the same stroke volume for both flat and convex surfaces (p < 0.001). Flow constraint by the concave surface resulted in the smallest jet areas (p < 0.001). The color Doppler jet areas on the curved surfaces were significantly smaller than the laser-illuminated dye visualization jet areas (p < 0.01 to 0.0001). However, at intermediate jet-surface distances (4 mm and sometimes 2 mm with higher velocity flows), jet interaction with the flat and especially with the convex surface resulted in larger jets. This effect was most pronounced on dye fluorescence studies because flow around these jets consisted mainly of low velocity vortical events with only partial surface adherence and these low velocity swirling flows were not well imaged by color Doppler technique. CONCLUSIONS: Our study suggests that the different-shaped adjacent surfaces with different degrees of flow alterations resulted in variable decreases in jet size and that color Doppler imaging could not encode and image the angled and low velocity swirling events well when jets flowed along the curved surfaces. These effects need to be taken into account when interpreting color Doppler images.

Calculation of aortic regurgitant volume by a new digital Doppler color flow mapping method: an animal study with quantified chronic aortic regurgitation.

OBJECTIVES: The aim of the present study was to quantitate aortic regurgitant volume and regurgitant fraction in a chronic animal model with surgically created aortic regurgitation using a new semiautomated color Doppler flow calculation method. BACKGROUND: The conventional noninvasive methods for evaluating the severity of aortic regurgitation have not been accepted widely nor compared with truly quantitative reference standards. METHODS: Eight to 20 weeks after aortic regurgitation was surgically induced in six sheep, a total of 22 hemodynamic states were studied. Electromagnetic flow probes and meters provided reference flow data. Epicardial color Doppler echocardiographic studies were performed to image left ventricular outflow tract forward and aortic regurgitant blood flows. The new method digitally integrated spatial and temporal color flow velocity data for left ventricular outflow tract forward flow and ascending aortic regurgitant flow. The pulsed Doppler method using the velocity-time integral was also used to obtain regurgitant volumes and regurgitant fractions. RESULTS: Regurgitant volumes and regurgitant fractions by the new method agreed well with those obtained electromagnetically, whereas the pulsed Doppler method overestimated these reference data (mean [+/-SD] difference 0.23 +/- 2.9 ml vs. 11 +/- 5.8 ml, p < 0.0001 for regurgitant volume; mean difference 1.2 +/- 7.6% vs. 19 +/- 13%, p < 0.0001 for regurgitant fraction). CONCLUSIONS: This animal study, using strictly quantified aortic regurgitant volumes, demonstrated that the digital color Doppler method provides accurate aortic regurgitant volumes and regurgitant fractions without cumbersome measurements.

Three-dimensional reconstruction of color Doppler flow convergence regions and regurgitant jets: an in vitro quantitative study.

OBJECTIVES: This study sought to investigate the applicability of a current implementation of a three-dimensional echocardiographic reconstruction method for color Doppler flow convergence and regurgitant jet imaging. BACKGROUND: Evaluation of regurgitant flow events, such as flow convergences or regurgitant jets, using two-dimensional imaging ultrasound color flow Doppler systems may not be robust enough to characterize these spatially complex events. METHODS: We studied two in vitro models using steady flow to optimize results. In the first constant-flow model, two different orifices were each mounted to produce flow convergences and free jets--a circular orifice and a rectangular orifice with orifice area of 0.24 cm(2). In another flow model, steady flows through a circular orifice were directed toward a curved surrounding wall to produce wall adherent jets. Video composite data of color Doppler flow images from both free jet and wall jet models were reconstructed and analyzed after computer-controlled 180 degrees rotational acquisition using a TomTec computer. RESULTS: For the free jet model there was an excellent relation between actual flow rates and three-dimensional regurgitant jet volumes for both circular and rectangular orifices (r = 0.99 and r = 0.98, respectively). However, the rectangular orifice produced larger jet volumes than the circular orifice, even at the same flow rates (p < 0.0001). Calculated flow rates by the hemispheric model using one axial measurement of the flow convergence isovelocity surface from two-dimensional color flow images underestimated actual flow rate by 35% for the circular orifice and by 44% for the rectangular orifice, whereas a hemielliptic method implemented using three axial measurements of the flow convergence zone derived using three-dimensional reconstruction correlated well with and underestimated actual flow rate to a lesser degree (22% for the circular orifice, 32% for the rectangular orifice). In the wall jet model, the jets were flattened against and spread along the wall and had reduced regurgitant jet volumes compared with free jets (p < 0.01). CONCLUSIONS: Three-dimensional reconstruction of flow imaged by color Doppler may add quantitative spatial information to aid computation methods that have been used for evaluating valvular regurgitation, especially where they related to complex geometric flow events.

Evaluation of aortic regurgitation with digitally determined color Doppler-imaged flow convergence acceleration: a quantitative study in sheep.

OBJECTIVES: The aim of the present study was to validate a digital color Doppler-based centerline velocity/distance acceleration profile method for evaluating the severity of aortic regurgitation. BACKGROUND: Clinical and in vivo experimental applications of the flow convergence axial centerline velocity/distance profile method have recently been used to estimate regurgitant flow rates and regurgitant volumes in the presence of mitral regurgitation. METHODS: In six sheep, a total of 19 hemodynamic states were obtained pharmacologically 14 weeks after the original operation in which a portion of the aortic noncoronary (n = 3) or right coronary (n = 3) leaflet was excised to produce aortic regurgitation. Echocardiographic studies were performed to obtain complete proximal axial flow acceleration velocity/distance profiles during the time of peak regurgitant flow (usually early in diastole) for each hemodynamic state. For each steady state, the severity of aortic regurgitation was assessed by measurement of the magnitude of the regurgitant flow volume/beat, regurgitant fraction and instantaneous regurgitant flow rates determined by using both aortic and pulmonary artery electromagnetic flow probes. RESULTS: Grade I regurgitation (regurgitant volume/beat < 15 ml, six conditions), grade II regurgitation (regurgitant volume/beat between 16 ml and 30 ml, five conditions) and grade III-IV regurgitation (regurgitant volume/beat > 30 ml, eight conditions) were clearly separated by using the color Doppler centerline velocity/distance profile domain technique. Additionally, an equation for correlating "a" (the coefficient from the multiplicative curve fit for the velocity/distance relation) with the peak regurgitant flow rates (Q [liters/min]) was derived showing a high correlation between calculated peak flow rates by the color Doppler method and the actual peak flow rates (Q = 13a + 1.0, r = 0.95, p < 0.0001, SEE = 0.76 liters/min). CONCLUSIONS: This study, using quantified aortic regurgitation, demonstrates that the flow convergence axial centerline velocity/distance acceleration profile method can be used to evaluate the severity of aortic regurgitation.

Interaliasing distance of the flow convergence surface for determining mitral regurgitant volume: a validation study in a chronic animal model.

OBJECTIVES: We aimed to validate a new flow convergence (FC) method that eliminated the need to locate the regurgitant orifice and that could be performed semiautomatedly. BACKGROUND: Complex and time-consuming features of previously validated color Doppler methods for determining mitral regurgitant volume (MRV) have prevented their widespread clinical use. METHODS: Thirty-nine different hemodynamic conditions in 12 sheep with surgically created flail leaflets inducing chronic mitral regurgitation were studied with two-dimensional (2D) echocardiography. Color Doppler M-mode images along the centerline of the accelerating flow towards the mitral regurgitation orifice were obtained. The distance between the two first aliasing boundaries (interaliasing distance [IAD]) was measured and the FC radius was mathematically derived according to the continuity equation (R(calc) = IAD/(1 - radicalv(1)/v(2)), v(1) and v(2) being the aliasing velocities). The conventional 2D FC radius was also measured (R(meas)). Mitral regurgitant volume was then calculated according to the FC method using both R(calc) and R(meas). Aortic and mitral electromagnetic (EM) flow probes and meters were balanced against each other to determine the reference standard MRV. RESULTS: Mitral regurgitant volume calculated from R(calc) and R(meas) correlated well with EM-MRV (y = 0.83x + 5.17, r = 0.90 and y = 1.04x + 0.91, r = 0.91, respectively, p < 0.001 for both). However, both methods resulted in slight overestimation of EM-MRV (Delta was 3.3 +/- 2.1 ml for R(calc) and 1.3 +/- 2.3 ml for R(meas)). CONCLUSIONS: Good correlation was observed between MRV derived from R(calc) (IAD method) and EM-MRV, similar to that observed with R(meas) (conventional FC method) and EM-MRV. The R(calc) using the IAD method has an advantage over conventional R(meas) in that it does not require spatial localization of the regurgitant orifice and can be performed semiautomatedly.

Outcome of patients with hypertrophic obstructive cardiomyopathy after percutaneous transluminal septal myocardial ablation and septal myectomy surgery.

OBJECTIVES: This study was conducted to evaluate follow-up results in patients with hypertrophic obstructive cardiomyopathy (HOCM) who underwent either percutaneous transluminal septal myocardial ablation (PTSMA) or septal myectomy. BACKGROUND: Controversy exists with regard to these two forms of treatment for patients with HOCM. METHODS: Of 51 patients with HOCM treated, 25 were treated by PTSMA and 26 patients via myectomy. Two-dimensional echocardiograms were performed before both procedures, immediately afterwards and at a three-month follow-up. The New York Heart Association (NYHA) functional class was obtained before the procedures and at follow-up. RESULTS: Interventricular septal thickness was significantly reduced at follow-up in both groups (2.3 +/- 0.4 cm vs. 1.9 +/- 0.4 cm for septal ablation and 2.4 +/- 0.6 cm vs. 1.7 +/- 0.2 cm for myectomy, both p < 0.001). Estimated by continuous-wave Doppler, the resting pressure gradient (PG) across the left ventricular outflow tract (LVOT) significantly decreased immediately after the procedures in both groups (64 +/- 39 mm Hg vs. 28 +/- 29 mm Hg for PTSMA, 62 +/- 43 mm Hg vs. 7 +/- 7 mm Hg for myectomy, both p < 0.0001). At three-month follow-up, the resting PG remained lower in the PTSMA and myectomy groups (24 +/- 19 mm Hg and 11 +/- 6 mm Hg, respectively, vs. those before procedures, both p < 0.0001). The NYHA functional class was also significantly improved in both groups (3.5 +/- 0.5 vs. 1.9 +/- 0.7 for PTSMA, 3.3 +/- 0.5 vs. 1.5 +/- 0.7 for myectomy, both p < 0.0001). CONCLUSIONS: Both myectomy and PTSMA reduce LVOT obstruction and significantly improve NYHA functional class in patients with HOCM. However, there are benefits and drawbacks for each therapeutic method that must be counterbalanced when deciding on treatment for LVOT obstruction.

Validation of real-time three-dimensional echocardiography for quantifying left ventricular volumes in the presence of a left ventricular aneurysm: in vitro and in vivo studies.

OBJECTIVES: To validate the accuracy of real-time three-dimensional echocardiography (RT3DE) for quantifying aneurysmal left ventricular (LV) volumes. BACKGROUND: Conventional two-dimensional echocardiography (2DE) has limitations when applied for quantification of LV volumes in patients with LV aneurysms. METHODS: Seven aneurysmal balloons, 15 sheep (5 with chronic LV aneurysms and 10 without LV aneurysms) during 60 different hemodynamic conditions and 29 patients (13 with chronic LV aneurysms and 16 with normal LV) underwent RT3DE and 2DE. Electromagnetic flow meters and magnetic resonance imaging (MRI) served as reference standards in the animals and in the patients, respectively. Rotated apical six-plane method with multiplanar Simpson's rule and apical biplane Simpson's rule were used to determine LV volumes by RT3DE and 2DE, respectively. RESULTS: Both RT3DE and 2DE correlated well with actual volumes for aneurysmal balloons. However, a significantly smaller mean difference (MD) was found between RT3DE and actual volumes (-7 ml for RT3DE vs. 22 ml for 2DE, p = 0.0002). Excellent correlation and agreement between RT3DE and electromagnetic flow meters for LV stroke volumes for animals with aneurysms were observed, while 2DE showed lesser correlation and agreement (r = 0.97, MD = -1.0 ml vs. r = 0.76, MD = 4.4 ml). In patients with LV aneurysms, better correlation and agreement between RT3DE and MRI for LV volumes were obtained (r = 0.99, MD = -28 ml) than between 2DE and MRI (r = 0.91, MD = -49 ml). CONCLUSIONS: For geometrically asymmetric LVs associated with ventricular aneurysms, RT3DE can accurately quantify LV volumes.

Decoy administration of NF-kappaB into the subarachnoid space for cerebral angiopathy.

Subarachnoid hemorrhage (SAH), encephalitis, meningitis, and autoimmune diseases sometimes lead to cerebral angiopathy, characterized specifically by narrowing of vessels, morphological changes in the structure of vessel walls, and a concomitant decrease in cerebral blood flow. Many patients also develop delayed ischemic neurological deficits. Thus, preventing vascular reactions is of paramount importance in treating SAH. Although cerebral vasospasm has some relationship with the inflammatory reaction of major cerebral vessels against the autologous blood, and many trials have attempted to prevent angiopathy after SAH, an effective treatment has not yet been established. The purpose of this article is to evaluate the preventive effect of nuclear factor KB (NF-kappaB) decoy oligo-DNA after SAH; since NF-kappaB is closely related to inflammation. In the rabbit angiopathy model after SAH, we evaluated the effectiveness of the decoy oligo-DNA using the angiographic (digital subtraction angiography) and histological (hematoxylin-eosin and Masson's trichrome staining) methods. Moreover, a gel-shift assay for NF-kappaB was also performed in order to evaluate the activity of NF-kappaB. We describe a new concept for treating cerebral angiopathy after SAH and for successfully inhibiting cerebral vasospasm and morphological changes in vessel walls in a rabbit model. In this treatment, we used synthetic double-strand oligo-DNA with a high affinity for transcription factor NF-kappaB, and cationic liposome complex administered through the cerebrospinal fluid.