936 resultados para Rational didactic reconstruction


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More than 2 years after undergoing anterior cruciate ligament (ACL) reconstruction, women still present bilateral asymmetries during multijoint movement tasks. Given the well-known ACL-injury gender bias, the goal of this study was to investigate whether males also present such asymmetries more than 2 years after undergoing ACL reconstruction. This study involved 12 participants submitted to ACL reconstruction in the ACL group and 17 healthy participants in the control group. The mean postoperative period was 37 months. The participants executed bilateral countermovement jumps and load squat tasks. The kinematics and ground reaction forces on each lower limb and pelvis were recorded, and used to compute bilateral peak vertical ground reaction forces, peak knee and hip joint powers in the sagittal plane, and the ratio between these powers. For the jump task, the groups had the same performance in the jump height, but for the ACL group the peak knee joint power on the operated side was 13% lower than on the non-operated side (p = 0.02). For the squat task, the hip-knee joint power ratio on the operated side of the ACL group was 31% greater than on the non-operated side (p = 0.02). The ACL group presented a deficit in the operated knee that had its energy generation over time (joint power) partially substituted by the hip joint power of the same side. The fact that, even after more than 2 years following the ACL reconstruction and returning to regular activity, the ACL group still had neuromuscular asymmetries suggests a need for improvement in the ACL reconstruction surgery procedures and/or rehabilitation protocols.

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The volumetric reconstruction technique presented in this paper employs a two-camera stereoscopic particle image velocimetry (SPIV) system in order to reconstruct the mean flow behind a fixed cylinder fitted with helical strakes, which are commonly used to suppress vortex-induced vibrations (VIV). The technique is based on the measurement of velocity fields at equivalent adjacent planes that results in pseudo volumetric fields. The main advantage over proper volumetric techniques is the avoidance of additional equipment and complexity. The averaged velocity fields behind the straked cylinders and the geometrical periodicity of the three-start configuration are used to further simplify the reconstruction process. Two straked cylindrical models with the same pitch (p = 10d) and two different heights (h = 0.1 and 0.2d) are tested. The reconstructed flow shows that the strakes introduce in the wake flow a well-defined wavelength of one-third of the pitch. Measurements of hydrodynamic forces, fluctuating velocity, vortex formation length, and vortex shedding frequency show the interdependence of the wake parameters. The vortex formation length is increased by the strakes, which is an important effect for the suppression of vortex-induced vibrations. The results presented complement previous investigations concerning the effectiveness of strakes as VIV suppressors and provide a basis of comparison to numerical simulations.

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Intravascular ultrasound (IVUS) image segmentation can provide more detailed vessel and plaque information, resulting in better diagnostics, evaluation and therapy planning. A novel automatic segmentation proposal is described herein; the method relies on a binary morphological object reconstruction to segment the coronary wall in IVUS images. First, a preprocessing followed by a feature extraction block are performed, allowing for the desired information to be extracted. Afterward, binary versions of the desired objects are reconstructed, and their contours are extracted to segment the image. The effectiveness is demonstrated by segmenting 1300 images, in which the outcomes had a strong correlation to their corresponding gold standard. Moreover, the results were also corroborated statistically by having as high as 92.72% and 91.9% of true positive area fraction for the lumen and media adventitia border, respectively. In addition, this approach can be adapted easily and applied to other related modalities, such as intravascular optical coherence tomography and intravascular magnetic resonance imaging. (E-mail: matheuscardosomg@hotmail.com) (C) 2011 World Federation for Ultrasound in Medicine & Biology.

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Thymidine monophosphate kinase (TMPK) has emerged as an attractive target for developing inhibitors of Mycobacterium tuberculosis growth. In this study the receptor-independent (RI) 4D-QSAR formalism has been used to develop QSAR models and corresponding 3D-pharmacophores for a set of 5`-thiourea-substituted alpha-thymidine inhibitors. Models were developed for the entire training set and for a subset of the training set consisting of the most potent inhibitors. The optimized (RI) 4D-QSAR models are statistically significant (r(2) = 0.90, q(2) = 0.83 entire set, r(2) = 0.86, q(2) = 0.80 high potency subset) and also possess good predictivity based on test set predictions. The most and least potent inhibitors, in their respective postulated active conformations derived from the models, were docked in the active site of the TMPK crystallographic structure. There is a solid consistency between the 3D-pharmacophore sites defined by the QSAR models and interactions with binding site residues. This model identifies new regions of the inhibitors that contain pharmacophore sites, such as the sugar-pyrimidine ring structure and the region of the 5`-arylthiourea moiety. These new regions of the ligands can be further explored and possibly exploited to identify new, novel, and, perhaps, better antituberculosis inhibitors of TMPKmt. Furthermore, the 3D-pharmacophores defined by these models can be used as a starting point for future receptor-dependent antituberculosis drug design as well as to elucidate candidate sites for substituent addition to optimize ADMET properties of analog inhibitors.

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Axial X-ray Computed tomography (CT) scanning provides a convenient means of recording the three-dimensional form of soil structure. The technique has been used for nearly two decades, but initial development has concentrated on qualitative description of images. More recently, increasing effort has been put into quantifying the geometry and topology of macropores likely to contribute to preferential now in soils. Here we describe a novel technique for tracing connected macropores in the CT scans. After object extraction, three-dimensional mathematical morphological filters are applied to quantify the reconstructed structure. These filters consist of sequences of so-called erosions and/or dilations of a 32-face structuring element to describe object distances and volumes of influence. The tracing and quantification methodologies were tested on a set of undisturbed soil cores collected in a Swiss pre-alpine meadow, where a new earthworm species (Aporrectodea nocturna) was accidentally introduced. Given the reduced number of samples analysed in this study, the results presented only illustrate the potential of the method to reconstruct and quantify macropores. Our results suggest that the introduction of the new species induced very limited chance to the soil structured for example, no difference in total macropore length or mean diameter was observed. However. in the zone colonised by, the new species. individual macropores tended to have a longer average length. be more vertical and be further apart at some depth. Overall, the approach proved well suited to the analysis of the three-dimensional architecture of macropores. It provides a framework for the analysis of complex structures, which are less satisfactorily observed and described using 2D imaging. (C) 2002 Elsevier Science B.V. All rights reserved.

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Objectives: Lung hyperinflation may be assessed by computed tomography (CT). As shown for patients with emphysema, however, CT image reconstruction affects quantification of hyperinflation. We studied the impact of reconstruction parameters on hyperinflation measurements in mechanically ventilated (MV) patients. Design: Observational analysis. Setting: A University hospital-affiliated research Unit. Patients: The patients were MV patients with injured (n = 5) or normal lungs (n = 6), and spontaneously breathing patients (n = 5). Interventions: None. Measurements and results: Eight image series involving 3, 5, 7, and 10 mm slices and standard and sharp filters were reconstructed from identical CT raw data. Hyperinflated (V-hyper), normally (V-normal), poorly (V-poor), and nonaerated (V-non) volumes were calculated by densitometry as percentage of total lung volume (V-total). V-hyper obtained with the sharp filter systematically exceeded that with the standard filter showing a median (interquartile range) increment of 138 (62-272) ml corresponding to approximately 4% of V-total. In contrast, sharp filtering minimally affected the other subvolumes (V-normal, V-poor, V-non, and V-total). Decreasing slice thickness also increased V-hyper significantly. When changing from 10 to 3 mm thickness, V-hyper increased by a median value of 107 (49-252) ml in parallel with a small and inconsistent increment in V-non of 12 (7-16) ml. Conclusions: Reconstruction parameters significantly affect quantitative CT assessment of V-hyper in MV patients. Our observations suggest that sharp filters are inappropriate for this purpose. Thin slices combined with standard filters and more appropriate thresholds (e.g., -950 HU in normal lungs) might improve the detection of V-hyper. Different studies on V-hyper can only be compared if identical reconstruction parameters were used.

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Background: Surgical resection in locally advanced breast cancer produces large defects that may not be suitable for primary closure. Immediate reconstruction is controversial and presents a complicated scenario for breast surgeons and plastic surgeons. Methods: In this study, a different design was planned for the latissimus dorsi musculocutaneous flap with primary closure in V-Y for the correction of major lesions in the anterior chest wall. Twenty-five patients underwent immediate locally advanced breast cancer reconstruction with a V-Y latissimus dorsi musculocutaneous flap. This flap was raised from adjacent tissue located on the lateral and posterior thoracic region and presented a triangular shape whose base was the lateral aspect of the mastectomy wound. The technique was indicated in patients with large thoracic wounds. Results: Mean follow-up time was 16 months. Closure was obtained in the donor and recipient sites without the use of skin grafts or other more major procedures. Complications occurred in nine patients (36 percent), including dorsal wound dehiscence in five patients and seroma in three. All cases except one were treated by a conservative approach with a good result. No total flap loss was reported. All patients achieved a satisfactory thoracic reconstruction and adequate wound care. Conclusions: The V-Y latissimus dorsi musculocutaneous flap is a reliable technique for immediate locally advanced breast cancer reconstruction. The technique is advantageous because the V-Y design allows primary closure of the chest wound and donor defect. Success depends on patient selection, coordinated planning with the breast cancer surgeon, and careful intraoperative management. (Plast. Reconstr. Surg. 127: 2186, 2011.)

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The main aim of this study is to evaluate the capacity of human dental pulp stem cells (hDPSC), isolated from deciduous teeth, to reconstruct large-sized cranial bone defects in nonimmunosuppressed (NIS) rats. To our knowledge, these cells were not used before in similar experiments. We performed two symmetric full-thickness cranial defects (5 x 8 mm) on each parietal region of eight NIS rats. In six of them, the left side was supplied with collagen membrane only and the right side (RS) with collagen membrane and hDPSC. In two rats, the RS had collagen membrane only and nothing was added at the left side (controls). Cells were used after in vitro characterization as mesenchymal cells. Animals were euthanized at 7, 20, 30, 60, and 120 days postoperatively and cranial tissue samples were taken from the defects for histologic analysis. Analysis of the presence of human cells in the new bone was confirmed by molecular analysis. The hDPSC lineage was positive for the four mesenchymal cell markers tested and showed osteogenic, adipogenic, and myogenic in vitro differentiation. We observed bone formation 1 month after surgery in both sides, but a more mature bone was present in the RS. Human DNA was polymerase chain reaction-amplified only at the RS, indicating that this new bone had human cells. The us e of hDPSC in NIS rats did not cause any graft. rejection. Our findings suggest that hDPSC is an additional cell resource for correcting large cranial defects in rats and constitutes a promising model for reconstruction of human large cranial defects in craniofacial surgery.

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Introduction: A resorbable collagen matrix with recombinant human bone morphogenetic protein (rhBMP-2) was compared with traditional iliac crest bone graft for the closure of alveolar defects during secondary dental eruption. Methods: Sixteen patients with unilateral cleft lip and palate, aged 8 to 12 years, were selected and randomly assigned to group 1 (rhBMP-2) or group 2 (iliac crest bone graft). Computed tomography was performed to assess both groups preoperatively and at months 6 and 12 postoperatively. Bone height and defect volume were calculated through Osirix Dicom Viewer (Pixmeo, Apple Inc.). Overall morbidity was recorded. Results: Preoperative and follow-up examinations revealed progressive alveolar bone union in all patients. For group 1, final completion of the defect with a 65.0% mean bone height was detected 12 months postoperatively. For group 2, final completion of the defect with an 83.8% mean bone height was detected 6 months postoperatively. Dental eruption routinely occurred in both groups. Clinical complications included significant swelling in three group 1 patients (37.5%) and significant donor-site pain in seven group 2 patients (87.5%). Conclusions: For this select group of patients with immature skeleton, rhBMP-2 therapy resulted in satisfactory bone healing and reduced morbidity compared with traditional iliac crest bone grafting.

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Reconstruction of the nipple-areola complex (NAC) is the last stage of breast reconstruction and represents the search for symmetry in regard to the contralateral breast. The objective of this study was to present an areola reconstruction technique with local skin graft to improve the texture and aspect of the reconstructed areola, searching for a natural look. This technique was performed on 122 patients who in the period from January 2000 to December 2005 were submitted to nipple and areola reconstruction. Once the position of the new nipple was determined, markings were made for the reconstruction of the areola. Then the external limit of the new areola was incised and the skin was centripetally deepidermized up to 85% of its diameter. After this procedure the detached skin was repositioned in its bed as a graft and sutured with 4.0 mononylon thread. Incisions with an 11-blade scalpel were then made in V and C forms associated with the detachment of this skin of the receptor area along the local graft so that at the end of the healing process they would determine alterations in the areolar texture mimicking the texture of a normal areola. All patients underwent tattooing 3 months after reconstruction of the NAC taking into account the different shades of the contralateral areola and nipple colors. The use of a local skin graft associated with C and V incisions allowed alteration in the texture of the reconstructed areola. The use of different ink shades for tattooing helped to give a tridimensional aspect to this areola. These factors determined a good aesthetic result in these patients. This areola reconstruction using a local skin graft allows change in the areola texture and a tridimensional aspect similar to that of a normal areola without the inconvenience of grafting from a distance.

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Background: Although the role of cartilage grafts in reconstruction of the posterior eyelid lamella is well established, spontaneous conjunctival epithelialization on such grafts has yet to be fully proven. The aim of this study was to perform a comparative analysis of the influence of perichondrium on conjunctival epithelialization over conchal cartilage grafts used in eyelid reconstruction in rabbits. Methods: The posterior lamellae of 100 lower eyelids from 50 rabbits were reconstructed with autogenous grafts of conchal ear cartilage. In the right eyelids, cartilage was grafted with the perichondrium in direct contact with the eyeball, and the left eyelids were reconstructed in a similar manner but using cartilage grafts without perichondrium. The animals were killed after 1, 2, 3, 4, and 5 weeks, and their lower eyelids were analyzed macroscopically and histologically. Results: The percentage difference in conjunctival epithelialization on the cartilage with perichondrium and that without perichondrium was 11.41 percent in the first week of the experiment, 13.64 percent in the second week, 18.69 percent in the third week, 10.38 percent in the fourth week, and 6.17 percent in the fifth week. The average percentage conjunctival epithelialization in the eyelids reconstructed with a cartilage graft with perichondrium was significantly higher throughout the 5 weeks of the experiment than in the eyelids reconstructed with cartilage without perichondrium (p < 0.0002). Conclusion: It was found that the perichondrium had an important role in conjunctival epithelialization in eyelids reconstructed with a cartilage graft in the present study. (Plast. Reconstr. Surg. 123: 55, 2009.)

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Various members of the bZip and bHLH-Zip families of eukaryotic transcription factors, including Jun, Fos, and Myc, have been identified as oncoproteins; mutation or deregulated expression of these proteins leads to certain types of cancer. These proteins can only bind to their cognate DNA enhancer sites following homodimerization, or heterodimerization with another family member, via their leucine zipper domain. Thus, a novel anticancer strategy would be to inhibit dimerization of these proteins, thereby blocking their DNA binding and transactivation functions. In this paper we show that it is possible to rationally design leucine zipper peptides that bind with high affinity to the leucine zipper dimerization domains of c-Jun and c-Fos, thus preventing the formation of functional c-Jun homodimers and c-Jun:c-Fos heterodimers; we refer to such peptides as superzippers (SZs). In vivo, c-Jun:SZ and c-Fos:SZ heterodimers should be nonfunctional as they lack one of the two basic domains that are essential for DNA binding. While the transport of a peptidic agent into cells often poses a severe obstacle to its therapeutic use, we show that a 46-residue leucine zipper peptide can be transported into HeLa cells by coupling it to a 17-residue carrier peptide from the Antennapedia homeodomain, thus paving the way for detailed studies of the therapeutic potential of superzipper peptides.

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Objectives: In cases of partial lesions of the intratemporal segment of the facial nerve, should the surgeon perform an intraoperative partial reconstruction, or partially remove the injured segment and place a graft? We present results from partial lesion reconstruction on the intratemporal segment of the facial nerve. Methods: A retrospective study on 42 patients who presented partial lesions on the intratemporal segment of the facial nerve was performed between 1988 and 2005. The patients were divided into 3 groups based on the procedure used: interposition of the partial graft on the injured area of the nerve (group 1; 12 patients); keeping the preserved part and performing tubulization (group 2; 8 patients); and dividing the parts of the injured nerve (proximal and distal) and placing a total graft of the sural nerve (group 3; 22 patients). Results: Fracture of the temporal bone was the most frequent cause of the lesion in all groups, followed by iatrogenic causes (p < 0.005). Those who obtained results lower than or equal to III on the House-Brackmann scale were 1 (8.3%) of the patients in group 1, none (0.0%) of the patients in group 2, and 15 (68.2%) of the patients in group 3 (p < 0.001). Conclusions: The best surgical technique for therapy of a partial lesion of the facial nerve is still questionable. Among these 42 patients, the best results were those from the total graft of the facial nerve.

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Background: Although various techniques have been used for breast conservation surgery reconstruction, there are few studies describing a logical approach to reconstruction of these defects. The objectives of this study were to establish a classification system for partial breast defects and to develop a reconstructive algorithm. Methods: The authors reviewed a 7-year experience with 209 immediate breast conservation surgery reconstructions. Mean follow-up was 31 months. Type I defects include tissue resection in smaller breasts (bra size A/B), including type IA, which involves minimal defects that do not cause distortion; type III, which involves moderate defects that cause moderate distortion; and type IC, which involves large defects that cause significant deformities. Type II includes tissue resection in medium-sized breasts with or without ptosis (bra size C), and type III includes tissue resection in large breasts with ptosis (bra size D). Results: Eighteen percent of patients presented type I, where a lateral thoracodorsal flap and a latissimus dorsi flap were performed in 68 percent. Forty-five percent presented type II defects, where bilateral mastopexy was performed in 52 percent. Thirty-seven percent of patients presented type III distortion, where bilateral reduction mammaplasty was performed in 67 percent. Thirty-five percent of patients presented complications, and most were minor. Conclusions: An algorithm based on breast size in relation to tumor location and extension of resection can be followed to determine the best approach to reconstruction. The authors` results have demonstrated that the complications were similar to those in other clinical series. Success depends on patient selection, coordinated planning with the oncologic surgeon, and careful intraoperative management.