62 resultados para Valve


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We describe two infants having an atrioventricular septal defect in the setting of a double inlet atrioventricular connection, but with patency of the left-sided valvar orifice and an imperforate right-sided valvar component, and a further case with atrioventricular septal defect and an imperforate Ebstein`s malformation, all producing the haemodynamic effect of tricuspid atresia. We make comparisons with the arrangement in trisomy 16 mice, in whom deficient atrioventricular septation is seen at times with the common atrioventricular junction exclusively connected to the left ventricle, a situation similar to that seen in two of our infants. We also review previous reports emphasising the important theoretical implication of the findings despite their rarity.

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Objective: To develop a new endoscopic approach to the correction of a myelomeningocele-like defect in fetal sheep. Methods: The fetuses of 9 pregnant ewes, with an average gestational age of 115 days, were subjected to a 3.0 x 2.0 cm removal of the skin over the lumbar spine, performed through hysterotomy. The uterus was closed, and three 5-mm endoscopic cannulas, without valve mechanisms, were inserted. In the pilot phase (2 animals), we initially worked exclusively in the amniotic fluid space. In the study phase, we partially withdrew the fetus from the amniotic fluid to completely expose its back. By simply allowing air to enter the amniotic cavity (without gas injection), a working space was created using a uterine lift device. The skin around the defect was dissected, and a biosynthetic cellulose material was applied to cover the area. A continuous suture of the skin was performed to completely hide the material. Results: The combined air/fluid space allowed the skin to be successfully closed in 6 out of 7 cases in the study phase. All fetuses were alive at the end of the procedures. Time to complete the endoscopic part of the procedure fell from 3 to 1 h by the end of this series. Premature birth occurred in 2 of the 4 cases allowed to continue with the pregnancy. Conclusion: A new gasless fetoscopic surgery technique was developed as an alternative to current techniques used for fetal endoscopic surgery. Copyright (C) 2008 S. Karger AG, Basel.

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Background and Aim: There were strong evidences that nitric oxide has capital importance in the progressive vasodilatation associated with varied circulatory shock forms, including systemic inflammatory response syndrome (SIRS), in patients undergoing cardiac surgeries for cardiopulmonary bypass (CPB). If CPB procedures, per se, are the inciting stimulus for inflammation, plasma nitrate/nitrite (NOx) excretion would be expected to be higher in these patients rather than in patients operated without CPB. In consequence, we hypothesized that increased levels of NOx would be predictive for vasoplegic syndrome. Methods: Thirty patients were assigned to three groups: Group 1-coronary artery bypass graft (CABG) roller pump CPB; Group 2-CABG centrifugal vortex pump CPB; and Group 3-heart valve surgery roller pump CPB. Sampling of venous blood for chemiluminescence plasma NOx dosage was achieved at the following time points: (1) before anesthesia induction; (2) after anesthesia induction; (3) before heparin infusion; (4) after heparin infusion; (5) CPB-30 minutes; (6) CPB-60 minutes; (7) before protamine infusion; (8) after protamine infusion; and (9) on return to the recovery area. Results: There were no intergroup differences regarding age and anesthetic regimen, and the number of arteries grafted was not different between the CABG groups. There were no NOx statistic differences, neither among the three groups of patients or among the surgery time. In addition, there was no correlation among NOx, lactate, and hemoglobin. Conclusions: Considering the inflammatory process intrinsic to CPB, this study reinforces the idea that plasma NOx is not useful as a biomarker of inflammatory response onset, which may or may not lead to SIRS and/or vasoplegic syndrome.

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Objective: The aims of this study were to assess the feasibility of performing a complete fetal echocardiographic study during the first trimester of pregnancy, to establish the best week to accomplish a complete evaluation, and to find a relationship between the diameters of the cardiac valves and gestational age. Methods: 46 fetuses with normal nuchal translucency and venous duct Doppler velocimetry were submitted to echocardiographic studies by the transvaginal approach between the 11 + 0 and 14 + 6 weeks of gestation. A complete echocardiographic evaluation was defined as an examination in which the three basic planes, four-chamber, longitudinal and short-axis views, were obtained. Results: The rates of complete echocardiography evaluation were 37, 85 and 100% at 11, 12 and 13-14 weeks, respectively. The longitudinal view was the easiest to obtain and the short-axis view was the most difficult one. The diameter of the cardiac valves was compared with the crown-rump length (CRL) and there was no statistically significant difference between either the diameters of the mitral and tricuspid or the aortic and pulmonary valves. A linear growth curve was constructed to demonstrate the diameter correlations. Conclusions: The study demonstrated the feasibility of a complete fetal echocardiographic evaluation by the transvaginal approach during the first trimester of gestation. The rate of a complete evaluation increased along the period and reached 100% when the CRL was 64 mm or 13 weeks of gestational age. There was a linear correlation between the cardiac valve diameters and the CRL revealing a relationship between the cardiac and fetal development. The absence of a statistically significant difference between the left and right valve dimensions possibly means that there is no predominance of right or left chambers during this period of evaluation. Copyright (C) 2007 S. Karger AG, Basel.

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Purpose: To evaluate the efficacy and safety of diode laser transscleral cyclophotocoagulation (DLTSC) to control intraocular pressure (IOP) in keratoprosthesis patients with uncontrolled glaucoma. Patients and Methods: Between 1993 and 2007, 18 eyes of 18 patients underwent DLTSC, either before (n = 3), during (n = I), or after (n = 14) keratoprosthesis surgery. Keratoprosthesis type 1 was used in 72%. All but one of these patients received an Ahmed Glaucoma Valve, either with or after the keratoprosthesis placement. Best-corrected visual acuity, IOP (assessed by digital palpation), number of medications, and complications were recorded preoperatively, at day 7, at 1, 3, and 6 months then every 6 months postoperatively. Results: Mean follow-tip was 26.6 +/- 19.6 months (mean +/- SD) and mean age was 50.1 +/- 15.6 years. Glaucoma was identified in 1 I eyes before keratoprosthesis surgery and in 7 eyes after. Mean postoperative IOP was significantly reduced at 6, 12, 24, 36, and 48 months after DLTSC. DLTSC was repeated in 6 eyes. At final visit, mean best-corrected visual acuity was not decreased and there were no statistically significant differences in the number of glaucoma medications. Two patients had complications after DLTSC: a conjunctival dehiscence and a fungal endophthalmitis. Conclusions: DLTSC has beneficial long-term effects in the control of IOP and can be considered in the management of keratoprosthesis patients with refractory glaucoma.

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Background: Although the influence of respiration on ventricular filling, as evaluated by Doppler technique, and the evaluation of diastolic velocities of mitral valve annulus (MVA), as measured by Doppler tissue imaging (DTI), can provide valuable information for the study of left ventricular (LV) diastolic function, the concomitant effects of aging, tidal volume (TV), and respiratory rate (RR) on these velocities have not been quantitatively investigated. Methods: We evaluated 12 normal male volunteers (Group I) aged 20-26 years (mean: 22.8) and 8 normal subjects aged 41 to 54 years old (mean: 45.9) (Group II). Using DTI we measured peak early (E-a) and late (A(a)) velocities of longitudinal axis expansion at lateral and medial MVA. Doppler mitral and tricuspid flow velocities were measured: peak early (E) and late (A) inflow velocity, early (E-i) and late (A(i)) flow integral, and deceleration time of peak early mitral flow velocity (DT). Respiratory cycles were simultaneously recorded at RR of 9, 12, 15, and 18 cycles/min and TV of 600 and 900 mL during respiration (RESP). Results and conclusions: (1) E, A, and A(i) in MV had negligible change during respiration, but E-i was significantly reduced during inspiration; (2) DT reduced slightly with inspiration, but the change was significant only with TV of 900 mL; (3) an important increase of E in right ventricular flow was observed during inspiration; (4) variations of RR and TV did not significantly influence right and left ventricular inflow in normal subjects, in the conditions of this investigation; (5) a significant increase of E-a at medial MVA was documented during inspiration only in young subjects; (6) a significant decrease of A(a) at medial MVA was observed during inspiration in both groups of volunteers; (7) RR and TV did not influence MVA velocities in young and adult subjects; (8) a consistent reduction in E-a and a significant increase in A(a) were observed with increasing age; (9) these changes were more conspicuous and consistent than those documented in ventricular filling when young and middle-age men are compared, suggesting that the DTI is more sensitive to detect changes in diastolic function; and (10) in addition, these data suggest that, for evaluation of diastolic function, in clinical context, it is not necessary to control rigorously RR or TV.

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Common features such as elastic fibre destruction, mucoid accumulation, and smooth muscle cell apoptosis are co-localized in aneurysms of the ascending aorta of various aetiologies. Recent experimental studies reported an activation of TGF-beta in aneurysms related to Marfan (and Loeys-Dietz) syndrome. Here we investigate TGF-beta signalling in normal and pathological human ascending aortic wall in syndromic and non-syndromic aneurysmal disease. Aneurysmal ascending aortic specimens, classified according to aetiology: syndromic MFS (n = 15, including two mutations in TGFBR2), associated with BAV (n = 15) or degenerative forms (n = 19), were examined. We show that the amounts of TGF-beta 1 protein retained within and released by aneurysmal tissue were greater than for control aortic tissue, whatever the aetiology, contrasting with an unchanged TGF-beta 1 mRNA level. The increase in stored TGF-beta 1 was associated with enhanced LTBP-I protein and mRNA levels. These dysiregulations of the extracellular ligand are associated with higher phosphorylated Smad2 and Smad2 mRNA levels in the ascending aortic wall from all types of aneurysm. This activation correlated with the degree of elastic fibre fragmentation. Surprisingly, there was no consistent association between the nuclear location of pSmad2 and extracellular TGF-beta 1 and LTBP-I staining and between their respective mRNA expressions. In parallel, decorin. was focally increased in aneurysmal media, whereas biglycan was globally decreased in aneurysmal aortas. In conclusion, this study highlights independent dysregulations of TGF-beta retention and Smad2 signalling in syndromic and non-syndromic aneurysms of the ascending aorta. Copyright (C) 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

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Homozygous familial hypercholesterolemia (HoFH) is a rare disorder characterized by the early onset of atherosclerosis, often at the ostia of coronary arteries. In this study we document for the first time that aortic and coronary atherosclerosis can be detected using 64 slice multiple detector row computed tomographic coronary angiography (CTCA). We studied five HoFH patients (three females, two males, mean age 19.8 +/- 2.9 years, age range 15-23 years, with a mean low density lipoprotein (LDL) cholesterol 618 +/- 211 mg/dL) using 64 slice CTCA. None of the patients showed evidence of ischemia with standard exercise testing. Calcified and mixed atherosclerotic plaques adjacent to or compromising the coronary artery ostia were found in all study subjects. Coronary plaques causing significant obstruction were found in one patient, who had previously undergone coronary artery bypass surgery and aortic valve replacement. Two other patients were noted to have non-obstructive calcified, mixed and non-calcified coronary artery plaques. Our data suggest that CTCA could be a useful non-invasive method for detection of early aortic and coronary atherosclerosis specifically affecting the coronary ostia in HoFH subjects. (c) 2007 Elsevier Ireland Ltd. All rights reserved.

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The objective of the current study was to characterize the internal nasal dimensions of children with repaired cleft lip and palate and transverse maxillary deficiency, using acoustic rhinometry and analyze the changes caused by rapid maxillary expansion (RME). A convenience sampling of 19 cleft lip and palate individuals, aged 14 to 18 years, of both sexes, previously submitted to primary surgeries and referred for RME were analyzed prospectively at the Hospital for Rehabilitation of Craniofacial Anomalies, University of Sao Paulo, Bauru, Sao Paulo, Brazil. All patients underwent acoustic rhinometry before installation of the expansor and at 30 and 180 days after the active expansion phase. Nasal cross-sectional areas and volumes corresponding to the nasal valve (CSA(1) and V(1)) and the turbinates (CSA(2), CSA(3), and V(2)) regions were determined before and after nasal decongestion. Rapid maxillary expansion led to a statistically significant increase (P < 0.05) in mean CSA(1), CSA(2), V(1), and V(2) (without nasal decongestion) and in CSA(1) and V(1) (with decongestion) in the group as a whole. Individual data analysis showed that 58% of the patients responded positively to RME, with an average increase in CSA(1) of 26% (with decongestion), whereas 37% of the patients had no significant change. Only 1 patient (5%) showed a decrease. The findings contribute toward the characterization of nasal deformities determined by the cleft and demonstrate the positive effect RME had on nasal morphophysiology in a significant number of the patients who underwent this procedure.

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The objective of the current study was to analyze the effects of rhinoseptoplasty on internal nasal dimensions and speech resonance of individuals with unilateral cleft lip and palate, estimated by acoustic rhinometry and nasometry, respectively. Twenty-one individuals (aged 15-46 years) with previously repaired unilateral cleft lip and palate were analyzed before (PRE), and 6 to 9 (POST1) and 12 to 18 months (POST2) after surgery. Acoustic rhinometry was used to measure the cross-sectional areas (CSAs) of segments corresponding to the nasal valve (CSA1), anterior portion (CSA2), and posterior portion (CSA3) of the lower turbinate, and the volumes at the nasal valve (V1) and turbinate (V2) regions at cleft and noncleft sides, before and after nasal decongestion with a topical vasoconstrictor. Nasometry was used to evaluate speech nasalance during the reading of a set of sentences containing nasal sounds and other devoid of nasal sounds. At the cleft side, before nasal decongestion, there was a significant increase (P < 0.05) in mean CSA1 and V1 values at POST1 and POST2 compared with PRE. After decongestion, increased values were also observed for CSA2 and V2 at POST2. No significant changes were observed at the noncleft side. Mean nasalance values at PRE, POST1, an POST2 were not different from each other in both oral and nasal sentences. The measurement of CSAs and volumes by acoustic rhinometry revealed that rhinoseptoplasty provided, in most cases analyzed, a significant increase in nasal patency, without concomitant changes in speech resonance, as estimated by nasalance assessment.

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The photoluminescence of anodically prepared ZrO(2) films was investigated. Morphological and microstructural analyses reveal an oxide surface covered by a high distribution of blisters and the major crystallographic structure is the monoclinic phase with small quantities of tetragonal phase. The photoluminescence reveals a broad emission band in the range between 350 and 650 nm. It was proposed that the photoluminescence mechanism is originated from the emission of a recombination center related to defects (oxygen vacancies) formed during Zr anodization. (C) 2008 Elsevier B.V. All rights reserved.

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This article describes a solid-state NMR (SSNMR) investigation of the influence of hydration and chemical cross-linking on the molecular dynamics of the constituents of the bovine pericardium (BP) tissues and its relation to the mechanical properties of the tissue. Samples of natural phenetylamine-diepoxide (DE)- and glutaraldehyde (GL)-fixed BP were investigated by (13)C cross-polarization SSNMR to probe the dynamics of the collagen, and the results were correlated to the mechanical properties of the tissues, probed by dynamical mechanical analysis. For samples of natural BP, the NMR results show that the higher the hydration level the more pronounced the molecular dynamics of the collagen backbone and sidechains, decreasing the tissue`s elastic modulus. In contrast, in DE- and GL-treated samples, the collagen molecules are more rigid, and the hydration seems to be less effective in increasing the collagen molecular dynamics and reducing the mechanical strength of the samples. This is mostly attributed to the presence of cross-links between the collagen plates, which renders the collagen mobility less dependent on the water absorption in chemically treated samples. Copyright (C) 2010 John Wiley & Sons, Ltd.

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The immersed boundary method is a versatile tool for the investigation of flow-structure interaction. In a large number of applications, the immersed boundaries or structures are very stiff and strong tangential forces on these interfaces induce a well-known, severe time-step restriction for explicit discretizations. This excessive stability constraint can be removed with fully implicit or suitable semi-implicit schemes but at a seemingly prohibitive computational cost. While economical alternatives have been proposed recently for some special cases, there is a practical need for a computationally efficient approach that can be applied more broadly. In this context, we revisit a robust semi-implicit discretization introduced by Peskin in the late 1970s which has received renewed attention recently. This discretization, in which the spreading and interpolation operators are lagged. leads to a linear system of equations for the inter-face configuration at the future time, when the interfacial force is linear. However, this linear system is large and dense and thus it is challenging to streamline its solution. Moreover, while the same linear system or one of similar structure could potentially be used in Newton-type iterations, nonlinear and highly stiff immersed structures pose additional challenges to iterative methods. In this work, we address these problems and propose cost-effective computational strategies for solving Peskin`s lagged-operators type of discretization. We do this by first constructing a sufficiently accurate approximation to the system`s matrix and we obtain a rigorous estimate for this approximation. This matrix is expeditiously computed by using a combination of pre-calculated values and interpolation. The availability of a matrix allows for more efficient matrix-vector products and facilitates the design of effective iterative schemes. We propose efficient iterative approaches to deal with both linear and nonlinear interfacial forces and simple or complex immersed structures with tethered or untethered points. One of these iterative approaches employs a splitting in which we first solve a linear problem for the interfacial force and then we use a nonlinear iteration to find the interface configuration corresponding to this force. We demonstrate that the proposed approach is several orders of magnitude more efficient than the standard explicit method. In addition to considering the standard elliptical drop test case, we show both the robustness and efficacy of the proposed methodology with a 2D model of a heart valve. (C) 2009 Elsevier Inc. All rights reserved.

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Optimization of photo-Fenton degradation of copper phthalocyanine blue was achieved by response surface methodology (RSM) constructed with the aid of a sequential injection analysis (SIA) system coupled to a homemade photo-reactor. Highest degradation percentage was obtained at the following conditions [H(2)O(2)]/[phthalocyanine] = 7, [H(2)O(2)]/[FeSO(4)] = 10, pH = 2.5, and stopped flow time in the photo reactor = 30 s. The SIA system was designed to prepare a monosegment containing the reagents and sample, to pump it toward the photo-reactor for the specified time and send the products to a flow-through spectrophotometer for monitoring the color reduction of the dye. Changes in parameters such as reagent molar ratios. residence time and pH were made by modifications in the software commanding the SI system, without the need for physical reconfiguration of reagents around the selection valve. The proposed procedure and system fed the statistical program with degradation data for fast construction of response surface plots. After optimization, 97% of the dye was degraded. (C) 2009 Elsevier B.V. All rights reserved.

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Background: Several methods have been utilized to prevent pericardial and retrosternal adhesions, but none of them evaluated the mesothelial regenerative hypothesis. There are evidences that the mesothelial trauma reduces pericardial fibrinolytic capability and induces an adhesion process. Keratinocyte growth factor (KGF) has proven to improve mesothelial cells proliferation. This study investigated the influence of keratinocyte growth factor in reducing post-surgical adhesions. Methods: Twelve pigs were operated and an adhesion protocol was employed. Following a stratified randomization, the animals received a topical application of KGF or saline. At 8 weeks, intrapericardial adhesions were evaluated and a severity score was established. The time spent to dissect the adhesions and the amount of sharp dissection used, were recorded. Histological sections were stained with sirius red and morphometric analyses were assessed with a computer-assisted image analysis system. Results: The severity score was lower in the KGF group than in the control group (11.5 vs 17, p = 0.005). The dissection time was lower in the KGF group (9.2 +/- 1.4 min vs 33.9 +/- 9.2 min, p = 0.004) and presented a significant correlation with the severity score (r = 0.83, p = 0.001). A significantly less sharp dissection was also required in the KGF group. Also, adhesion area and adhesion collagen were significantly tower in the KGF group than in the control group. Conclusion: The simulation of pericardial cells with KGF reduced the intensity of postoperative adhesions and facilitated the re-operation. This study suggests that the mesothelial regeneration is the new horizon in anti-adhesion therapies. (C) 2008 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.