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1.
World Neurosurg ; 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38548046

RESUMO

BACKGROUND: Superficial temporal artery (STA)-middle cerebral artery (MCA) bypass surgery has been widely adopted in treating moyamoya disease (MMD). Geometric variations including high tortuosity and stenosis exist in many cases, but the hemodynamic effects have not been comprehensively evaluated. We aim to evaluate the hemodynamic effects of bypass geometry variations based on patient-specific data. METHODS: In total, 17 patients with MMD who underwent STA-MCA bypass surgery with highly tortuous bypass geometry were included. For each patient, the original 3-dimensional structure of STA-MCA bypass was reconstructed from clinical imaging data. The bypass structure was virtually improved by removing the tortuosity and stenosis. Computational fluid dynamics simulation was performed on both bypass structures under identical patient-specific condition. The simulated hemodynamic parameters of the bypass and its distal branches were compared between the original and virtually improved bypass geometries in all cases using paired t-test or Wilcoxon signed-rank test. The changes of hemodynamic parameters were compared between the cases with and without mild-to-moderate stenosis (44.0-70.3% in diameter) in the bypass using t-test or Mann-Whitney U test. RESULTS: The virtual improvement of bypass geometry significantly increased the flow rate of the bypass and its distal branches (P < 0.05) and decreased the transcranial flow resistance (P < 0.05). The hemodynamic changes in cases with stenosis removal were significantly greater than those without stenosis (P < 0.05). CONCLUSIONS: High tortuosity and stenosis can significantly change the hemodynamics of STA-MCA bypass, and the optimization of bypass geometry deserves further consideration.

2.
J Cell Mol Med ; 27(15): 2136-2149, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37264501

RESUMO

The preparation of biodegradable scaffolds loaded with cells and cytokine is a feature of tissue-engineered skin. IPSCs-based tissue-engineered skin treatment for wound repair is worth exploring. Healthy human skin fibroblasts were collected and reprogrammed into iPSCs. After gene modification and induction, CK19+ /Integrinß1+ /CD200+ VEGF165 gene-modified iPS-HFSCsGFP were obtained and identified by a combination of immunofluorescence and RT-qPCR. Astragalus polysaccharide-containing 3D printed degradable scaffolds were prepared and co-cultured with VEGF165 gene-modified iPS-HFSCsGFP , and the biocompatibility and spatial structure of the tissue-engineered skin was analysed by cell counting kit-8 (CCK8) assay and scanning electron microscopy. Finally, the tissue-engineered skin was transplanted onto the dorsal trauma of nude mice, and the effect of tissue-engineered skin on the regenerative repair of total skin defects was evaluated by a combination of histology, immunohistochemistry, immunofluorescence, RT-qPCR, and in vivo three-dimensional reconstruction under two-photon microscopy. CK19+ /Integrinß1+ /CD200+ VEGF165 gene-modified iPS-HFSCsGFP , close to the morphology and phenotype of human-derived hair follicle stem cells, were obtained. The surface of the prepared 3D printed degradable scaffold containing 200 µg/mL astragalus polysaccharide was enriched with honeycomb-like meshwork, which was more conducive to the proliferation of the resulting cells. After tissue-engineered skin transplantation, combined assays showed that it promoted early vascularization, collagen and hair follicle regeneration and accelerated wound repair. VEGF165 gene-modified iPS-HFSCsGFP compounded with 3D printed degradable scaffolds containing 200 µg/mL astragalus polysaccharide can directly and indirectly participate in vascular, collagen, and hair follicle regeneration in the skin, achieving more complete structural and functional skin regenerative repair.


Assuntos
Transplante de Pele , Fator A de Crescimento do Endotélio Vascular , Camundongos , Animais , Humanos , Transplante de Pele/métodos , Fator A de Crescimento do Endotélio Vascular/genética , Camundongos Nus , Estudos de Viabilidade , Engenharia Tecidual/métodos , Tecidos Suporte/química , Colágeno , Polissacarídeos/farmacologia , Impressão Tridimensional
4.
Zhongguo Gu Shang ; 36(2): 110-5, 2023 Feb 25.
Artigo em Chinês | MEDLINE | ID: mdl-36825408

RESUMO

OBJECTIVE: To evaluate the clinical outcomes of reverse total shoulder arthroplasty as a revision procedure for the failed fixation of proximal humeral fractures in the elderly patients. METHODS: A retrospective analysis was performed on 8 patients with failed internal fixation of proximal humeral fractures from May 2014 to March 2020, including 3 males and 5 females, aged from 65 to 75 years old. All 8 patients underwent reverse total shoulder arthroplasty, and the mean time between initial fixation and reverse total shoulder arthroplasty ranged from 8 to 16 months. Range of motion(ROM), University of California at Los Angeles(UCLA) shoulder score, visual analogue scale (VAS), self-rating anxiety scale(SAS), and Constant-Murley score of shoulder function were assessed pre-operatively and at the last follow-up. Complications relating to the surgery were recorded. RESULTS: All 8 patients successfully followed up. The mean follow-up after reverse total shoulder arhroplasty ranged from 16 to 28 months. The range of motion (forward flexion, external rotation, abduction and internal rotation) of the affected shoulder was significantly improved after surgery, and the post-operative VAS, SAS and UCLA scores were also significantly improved. For the Constant-Murley score of shoulder joint function, the total scores and the subscores of pain, daily activities, range of motion and strength test at the last follow-up were all significantly improved. Scapular glenoid notch was observed in patient, which was evaluated as grade 1 on imaging. All the other patients did not develop specific or non-specific complications. CONCLUSION: Reverse total shoulder arhroplasty is an appropriate treatment as a revision surgery for failed fixation of proximal humeral fractures. It has shown satisfactory clinical outcomes, accelerating the rehabilitation of shoulder function and improving the quality of life.


Assuntos
Artroplastia do Ombro , Fraturas do Ombro , Articulação do Ombro , Masculino , Feminino , Humanos , Idoso , Ombro/cirurgia , Artroplastia do Ombro/efeitos adversos , Artroplastia do Ombro/métodos , Estudos Retrospectivos , Resultado do Tratamento , Qualidade de Vida , Articulação do Ombro/cirurgia , Fraturas do Ombro/cirurgia , Úmero/cirurgia , Amplitude de Movimento Articular
5.
IEEE Trans Biomed Eng ; 70(5): 1683-1691, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36441885

RESUMO

OBJECTIVE: Noninvasive fractional flow reserve (FFR) has been extensively studied and gained clinical recognition. However, the effect of an interventional catheter and a pressure wire in the arteries on the noninvasive FFR was not considered in previous studies. We provide quantitative analysis of how a catheter and a pressure wire can affect the estimation of noninvasive FFR using computational fluid dynamics (CFD) techniques. METHODS: Six patients are studied. We calibrate our CFD model with patient-specific conditions so that the noninvasive FFR matches the FFR measured by the pressure wire. Then, we numerically remove the pressure wire and compute the noninvasive FFR again. This allows us to analyze the effect of the pressure wire on FFR. RESULTS: The presence of a catheter and a pressure wire can reduce distal pressure from -0.1 mmHg to -8.1 mmHg, resulting in a reduction of FFR by 5.8 % in average (0.012 to 0.107 or -1.2 % to -16.8 %). The insertion also reduces the time-averaged flow rate at the stenosis by up to 16.2 % (4.9 % in average). CONCLUSION: The impact of the pressure wire on the measured FFR depends on the characteristics of the patient-specific lesion. Significant linear correlations are found between the minimum diameter of the stenotic arteries and the reduction in FFR. SIGNIFICANCE: The impact we found may contribute to provide a correction and improve the estimation of the noninvasive FFR technique for use in clinical practice.


Assuntos
Estenose Coronária , Reserva Fracionada de Fluxo Miocárdico , Humanos , Angiografia Coronária/métodos , Vasos Coronários , Hemodinâmica , Valor Preditivo dos Testes , Índice de Gravidade de Doença
6.
Am J Transl Res ; 14(8): 5552-5562, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36105013

RESUMO

INTRODUCTION: Accurate and rapid assessment of the coronary microcirculation has become an important medical challenge. However, reliable and non-invasive quantitative methods to diagnose coronary microvascular disease (CMVD), select treatments for coronary artery disease (CAD), and therefore improve coronary microcirculation are lacking. Current detection methods have limitations. Therefore, we will assess whether a new detection method, the non-invasive index of microcirculatory resistance (IMR), based on computed tomography (CT) perfusion and hydrodynamics (CT-IMR), can effectively evaluate the function of coronary microvessels. METHODS: We will conduct a multicenter, randomized, open-label study, including a Phase I single-center and Phase II multicenter trial, to assess the accuracy of the non-invasive CT-IMR coronary measurement of microcirculation function. The study will enroll 295 patients who will undergo coronary CT angiography (CCTA), dynamic CT-myocardial perfusion imaging (CT-MPI), invasive coronary angiography (ICA), and invasive IMR. This study will identify the key influencing factors when calculating myocardial microcirculation perfusion and develop an accurate three-dimensional coronary reconstruction method and a non-invasive coronary IMR calculation method based on computational fluid dynamics (CFD). This will facilitate the development of a non-invasive system to detect and measure coronary microcirculation. CONCLUSION: The clinical trial for computed tomography myocardial perfusion based non-invasive index of microcirculatory resistance (MPBIMR) will establish the key influencing factors when calculating myocardial microcirculation perfusion and create a non-invasive CT-IMR calculation method based on CFD. This method may diagnose patients with simple coronary microvascular lesions and those with coronary microvascular lesions combined with coronary vascular lesions.

7.
Comput Methods Programs Biomed ; 224: 107004, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35841853

RESUMO

BACKGROUND: An efficient and accurate blood flow simulation can be useful for understanding many vascular diseases. Accurately resolving the blood flow velocity based on patient-specific geometries and model parameters is still a major challenge because of complex geomerty and turbulence issues. In addition, obtaining results in a short amount of computing time is important so that the simulation can be used in the clinical environment. In this work, we present a parallel scalable method for the patient-specific blood flow simulation with focuses on its parallel performance study and clinical verification. METHODS: We adopt a fully implicit unstructured finite element method for a patient-specific simulation of blood flow in a full precerebral artery. The 3D artery is constructed from MRI images, and a parallel Newton-Krylov method preconditioned with a two-level domain decomposition method is adopted to solve the large nonlinear system discretized from the time-dependent 3D Navier-Stokes equations in the artery with an integral outlet boundary condition. The simulated results are verified using the clinical data measured by transcranial Doppler ultrasound, and the parallel performance of the algorithm is studied on a supercomputer. RESULTS: The simulated velocity matches the clinical measured data well. Other simulated blood flow parameters, such as pressure and wall shear stress, are within reasonable ranges. The results show that the parallel algorithm scales up to 2160 processors with a 49% parallel efficiency for solving a problem with over 20 million unstructured elements on a supercomputer. For a standard cerebral blood flow simulation case with approximately 4 million finite elements, the calculation of one cardiac cycle can be finished within one hour with 1000 processors. CONCLUSION: The proposed method is able to perform high-resolution 3D blood flow simulations in a patient-specific full precerebral artery within an acceptable time, and the simulated results are comparable with the clinical measured data, which demonstrates its high potential for clinical applications.


Assuntos
Algoritmos , Modelos Cardiovasculares , Velocidade do Fluxo Sanguíneo/fisiologia , Circulação Cerebrovascular , Simulação por Computador , Humanos
8.
Comput Methods Programs Biomed ; 213: 106497, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34749243

RESUMO

BACKGROUND: Cerebral hemodynamic disorders are involved in the occurrence and progression of vascular dementia (VaD), but the methods to detect hemodynamics remainmultifarious and uncertain nowadays. We aim to exploit a computational fluid dynamics (CFD) approach by static and dynamic parameters, which can be used to detect individual cerebrovascular hemodynamics quantitatively. METHODS: A patient-specific CFD model was constructed with geometrical arteries on the magnetic resonance angiography (MRA) and hemodynamic parameters on ultrasound Doppler, by which, the structural and simulated hemodynamic indexes could be obtained, mainly including the cerebral arterial volume (CAV), the number of visible arterial outlets, the total cerebral blood flow (tCBF) index and the total cerebrovascular resistance (tCVR) index. The hemodynamics were detected in subcortical vascular dementia (SVaD) patients (n = 38) and cognitive normal controls (CNCs; n = 40). RESULTS: Compared with CNCs, the SVaD patients had reduced outlets, CAV and tCBF index (all P ≤ 0.001), increased volume of white matter hyperintensity (WMH) and tCVR index (both P ≤ 0.01). The fewer outlets (OR = 0.77), higher Hachinski ischemic score (HIS) (OR = 3.65), increased tCVR index (OR = 1.98) and volume of WMH (OR = 1.12) were independently associated with SVaD. All hemodynamic parameters could differentiate the SVaD patinets and CNCs, especially the composite index calculated by outlets, tCVR index and HIS (AUC = 0.943). Fewer outlets and more WMH increased the odds of SVaD, which were partly mediated by the tCBF index (14.4% and 13.0%, respectively). CONCLUSION: The reduced outlets, higher HIS and tCVR index may be independent risk factors for the SVaD, and a combination of these indexes can differentiate SVaD patients and CNCs reliably. The tCBF index potentially mediates the relationships between hemodynamic indexes and SVaD. Although all simulated indexes only represented the true hemodynamics indirectly, this CFD model can provide patient-specific hemodynamic alterations non-invasively and conveniently.


Assuntos
Demência Vascular , Algoritmos , Circulação Cerebrovascular , Demência Vascular/diagnóstico por imagem , Hemodinâmica , Humanos , Hidrodinâmica
9.
J Int Med Res ; 49(11): 3000605211058871, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34812073

RESUMO

Charcot arthropathy is a type of destructive osteoarthropathy characterized by neurotrophic and sensory disorders. The condition is relatively rare, with an insidious onset, and it is easily misdiagnosed. Total knee arthroplasty (TKA) can cause excessive joint wear, continuous inflammatory stimulation of the prosthesis, postoperative residual cavity, prosthesis loosening and subsidence, peripheral fracture, infection, and other complications. Furthermore, these complications are more likely to occur in patients with Charcot arthropathy because of disease-specific pathological characteristics, when TKA is performed. Therefore, Charcot arthropathy was once a contraindication to TKA. Recently, with the optimization of joint prostheses and the maturity of surgical techniques, more studies have reported successful cases of TKA in patients with Charcot arthropathy. We report a case of Charcot arthropathy in our hospital, and describe the patient's medical history, clinical symptoms, signs, imaging findings, diagnosis, and the entire TKA process, to explore the TKA strategy and prosthesis selection in a patient with Charcot arthropathy.


Assuntos
Artropatia Neurogênica , Artroplastia do Joelho , Prótese do Joelho , Artropatia Neurogênica/diagnóstico por imagem , Artropatia Neurogênica/cirurgia , Humanos , Articulação do Joelho/diagnóstico por imagem , Articulação do Joelho/cirurgia , Rotação
10.
Sci Rep ; 11(1): 19507, 2021 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-34593943

RESUMO

Partial differential equations (PDEs) are ubiquitous in natural science and engineering problems. Traditional discrete methods for solving PDEs are usually time-consuming and labor-intensive due to the need for tedious mesh generation and numerical iterations. Recently, deep neural networks have shown new promise in cost-effective surrogate modeling because of their universal function approximation abilities. In this paper, we borrow the idea from physics-informed neural networks (PINNs) and propose an improved data-free surrogate model, DFS-Net. Specifically, we devise an attention-based neural structure containing a weighting mechanism to alleviate the problem of unstable or inaccurate predictions by PINNs. The proposed DFS-Net takes expanded spatial and temporal coordinates as the input and directly outputs the observables (quantities of interest). It approximates the PDE solution by minimizing the weighted residuals of the governing equations and data-fit terms, where no simulation or measured data are needed. The experimental results demonstrate that DFS-Net offers a good trade-off between accuracy and efficiency. It outperforms the widely used surrogate models in terms of prediction performance on different numerical benchmarks, including the Helmholtz, Klein-Gordon, and Navier-Stokes equations.

11.
Comput Biol Med ; 136: 104652, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34329862

RESUMO

Surgical planning for aortic aneurysm repair is a difficult task. In addition to the morphological features obtained from medical imaging, alternative features obtained with computational modeling may provide additional useful information. Though numerical studies are noninvasive, they are often time-consuming, especially when we need to study and compare multiple repair scenarios, because of the high computational complexity. In this paper, we present a highly parallel algorithm for the numerical simulation of unsteady blood flows in the patient-specific abdominal aorta before and after the aneurysmic repair. We model the blood flow with the unsteady incompressible Navier-Stokes equations with different outlet boundary conditions, and solve the discretized system with a highly scalable domain decomposition method. With this approach, a high resolution simulation of a full-size adult aorta can be obtained in less than an hour, instead of days with older methods and software. In addition, we show that the parallel efficiency of the proposed method is near 70% on a parallel computer with 2, 880 processor cores.


Assuntos
Aneurisma , Aorta Abdominal , Aorta Abdominal/diagnóstico por imagem , Diagnóstico por Imagem , Hemodinâmica , Humanos
12.
Eur Radiol ; 31(12): 8967-8974, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34032918

RESUMO

OBJECTIVES: We attempted to improve the accuracy of coronary CT angiography (CCTA)-derived fractional flow reserve (FFR) (FFRCT) by expanding the coronary tree in the computational fluid dynamics (CFD) domain. An observational study was performed to evaluate the effects of extending the coronary tree analysis for FFRCT from a minimal diameter of 1.2 to 0.8 mm. METHODS: Patients who underwent CCTA and interventional FFR were enrolled retrospectively. Seventy-six patients qualified based on the inclusion criteria. The three-dimensional (3D) coronary artery tree was reconstructed to generate a finite element mesh for each subject with different lower limits of luminal diameter (1.2 mm and 0.8 mm). Outlet boundary conditions were defined according to Murray's law. The Newton-Krylov-Schwarz (NKS) method was applied to solve the governing equations of CFD to derive FFRCT. RESULTS: At the individual patient level, extending the minimal diameter of the coronary tree from 1.2 to 0.8 mm improved the sensitivity of FFRCT by 16.7% (p = 0.022). This led to the conversion of four false-negative cases into true-positive cases. The AUC value of the ROC curve increased from 0.74 to 0.83. Moreover, the NKS method can solve the computational problem of extending the coronary tree to an 0.8-mm luminal diameter in 10.5 min with 2160 processor cores. CONCLUSIONS: Extending the reconstructed coronary tree to a smaller luminal diameter can considerably improve the sensitivity of FFRCT. The NKS method can achieve favorable computational times for future clinical applications. KEY POINTS: • Extending the reconstructed coronary tree to a smaller luminal diameter can considerably improve the sensitivity of FFRCT. • The NKS method applied in our study can effectively reduce the computational time of this process for future clinical applications.


Assuntos
Doença da Artéria Coronariana , Estenose Coronária , Reserva Fracionada de Fluxo Miocárdico , Angiografia por Tomografia Computadorizada , Angiografia Coronária , Vasos Coronários/diagnóstico por imagem , Humanos , Valor Preditivo dos Testes , Estudos Retrospectivos , Índice de Gravidade de Doença , Tomografia Computadorizada por Raios X
13.
Phys Rev E ; 103(2-1): 023306, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33736091

RESUMO

In this paper, a finite-volume discrete Boltzmann method based on a cell-centered scheme for inviscid compressible flows on unstructured grids is presented. In the new method, the equilibrium distribution functions are obtained from the circle function in two-dimensions (2D) and the spherical function in three-dimensions (3D). Moreover, the advective fluxes are evaluated by Roe's flux-difference splitting scheme, the gradients of the density and total energy distribution functions are computed with a least-squares method, and the Venkatakrishnan limiter is employed to prevent oscillations. To parallelize the method we use a graph-based partitioning approach that also guarantees the load balancing. The method is validated by seven benchmark problems: (a) a 2D flow pasting a bump, (b) a 2D Riemann problem, (c) a 2D flow passing the RAE2822 airfoil, (d) flows passing the NACA0012 airfoil, (e) 2D supersonic flows around a cylinder, (f) an explosion in a 3D box, and (g) a 3D flow around the ONERA M6 wing. The benchmark tests show that the results obtained by the proposed method match well with the published results, and the parallel numerical experiments show that the proposed parallel implementation has close to linear strong scalability, and parallel efficiencies of 95.31% and 94.56% are achieved for 2D and 3D problems on a supercomputer with up to 4800 processor cores, respectively.

14.
Int J Numer Method Biomed Eng ; 37(6): e3451, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33609008

RESUMO

Computational hemodynamics is being developed as an alternative approach for assisting clinical diagnosis and treatment planning for liver diseases. The technology is non-invasive, but the computational time could be high when the full geometry of the blood vessels is taken into account. Existing approaches use either one-dimensional model of the artery or simplified three-dimensional tubular geometry in order to reduce the computational time, but the accuracy is sometime compromised, for example, when simulating blood flows in arteries with plaque. In this work, we study a highly parallel method for the transient incompressible Navier-Stokes equations for the simulation of the blood flows in the full three-dimensional patient-specific hepatic artery, portal vein and hepatic vein. As applications, we also simulate the flow in a patient with hepatectomy and calculate the S (PPG). One of the advantages of simulating blood flows in all hepatic vessels is that it provides a direct estimate of the PPG, which is a gold standard value to assess the portal hypertension. Moreover, the robustness and scalability of the algorithm are also investigated. A 83% parallel efficiency is achieved for solving a problem with 7 million elements on a supercomputer with more than 1000 processor cores.


Assuntos
Algoritmos , Hemodinâmica , Artérias , Simulação por Computador , Veias Hepáticas , Humanos
15.
Biomech Model Mechanobiol ; 20(3): 909-924, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33582934

RESUMO

The abdominal aorta is the largest artery in the abdominal cavity that supplies blood flows to vital organs through the complex visceral arterial branches, including the celiac trunk (the liver, stomach, spleen, etc.), the renal arteries (the kidneys) and the superior and inferior mesenteric arteries (the small and large intestine, pancreas, etc.). An accurate simulation of blood flows in this network of arteries is important for the understanding of the hemodynamics in various organs of healthy and diseased patients, but the computational cost is very high. As a result, most researchers choose to focus on a portion of the artery or use a low-dimensional approximation of the artery. In the present work, we introduce a parallel algorithm for the modeling of pulsatile flows in the abdominal aorta with branches to the primary organs, and an organ-based two-level method for calculating the resistances for the outflow boundary conditions. With this highly parallel approach, the simulation of the blood flow for a cardiac cycle of the anatomically detailed aorta can be obtained within a few hours, and the blood distribution to organs including liver, spleen and kidneys are also computed with certain accuracy. Moreover, we discuss the significant hemodynamic differences resulted from the influence of the peripheral branches. In addition, we examine the accuracy of the results with respect to the mesh size and time-step size and show the high parallel scalability of the proposed algorithm with up to 3000 processor cores.


Assuntos
Aorta Abdominal/fisiologia , Simulação por Computador , Análise Numérica Assistida por Computador , Especificidade de Órgãos , Fluxo Sanguíneo Regional/fisiologia , Algoritmos , Aorta Abdominal/diagnóstico por imagem , Velocidade do Fluxo Sanguíneo/fisiologia , Humanos , Pressão , Fatores de Tempo , Tomografia Computadorizada por Raios X , Resistência Vascular/fisiologia
16.
Int J Numer Method Biomed Eng ; 36(11): e3392, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32783371

RESUMO

Numerical simulation of blood flows in patient-specific arteries can be useful for the understanding of vascular diseases, as well as for surgery planning. In this paper, we simulate blood flows in the full cerebral artery of stroke patients. To accurately resolve the flow in this rather complex geometry with stenosis is challenging and it is also important to obtain the results in a short amount of computing time so that the simulation can be used in pre- and/or post-surgery planning. For this purpose, we introduce a highly scalable, parallel non-nested two-level domain decomposition method for the three-dimensional unsteady incompressible Navier-Stokes equations with an impedance outlet boundary condition. The problem is discretized with a stabilized finite element method on unstructured meshes in space and a fully implicit method in time, and the large nonlinear systems are solved by a preconditioned parallel Newton-Krylov method with a two-level Schwarz method. The key component of the method is a non-nested coarse problem solved using a subset of processor cores and its solution is interpolated to the fine space using radial basis functions. To validate and verify the proposed algorithm and its highly parallel implementation, we consider a case with available clinical data and show that the computed result matches with the measured data. Further numerical experiments indicate that the proposed method works well for realistic geometry and parameters of a full size cerebral artery of an adult stroke patient on a supercomputers with thousands of processor cores.


Assuntos
Artérias Cerebrais , Modelos Cardiovasculares , Acidente Vascular Cerebral , Algoritmos , Simulação por Computador , Humanos
17.
Ann Palliat Med ; 9(5): 3059-3069, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32819134

RESUMO

BACKGROUND: The sustained negative pressure created by vacuum sealing drainage (VSD) on exposed vascular wounds can result in blood vessel compression, embolism, or necrosis. The objective of this research was to explore the ability of an experimental vascular protective shield combined with VSD to protect exposed vessels of the lower limbs and accelerate wound repair. METHODS: (I) The vascular protective shield was prepared; (II) the material was subjected to acute toxicity and hemolysis tests; (III) and 30 New Zealand rabbits were divided into three groups: the control, VSD-only, and combined shield-VSD groups (with ten rabbits in each group). The wound-healing rate, myocardial function, wound histopathology, expression of angiogenesis markers, and exposed vascular compression of these three groups were compared on day 7. RESULTS: (I) The internal structure of the material was smooth; and (II) no toxicity or death was observed in mice of any group. The hemolysis rate in the combined shield-VSD group was very low. (III) The combined shield-VSD group showed a higher wound-healing rate, and higher levels of cluster of differentiation 31 (CD31), vascular endothelial growth factor (VEGF), and platelet-derived growth factor (PDGF), than the other groups (P<0.05), along with a better tissue healing rate. (IV) Left ventricular pressure fluctuations in the combined shield-VSD group were smaller than those in the VSD-only group (P<0.05). (V) Blood vessels in the control and combined shield-VSD group were not damaged, but were damaged in the VSD-only group. CONCLUSIONS: The experimental vascular protective shield exhibited exceptional biosafety. The combination of this shield with VSD reduces influences on systolic and diastolic capacities of myocardium and avoids multiple compressions of exposed vessels, thus contributing to early vascularization of wounds and wound repair.


Assuntos
Tratamento de Ferimentos com Pressão Negativa , Animais , Drenagem , Camundongos , Coelhos , Vácuo , Fator A de Crescimento do Endotélio Vascular , Cicatrização
18.
Ann Palliat Med ; 9(4): 1462-1475, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32692201

RESUMO

BACKGROUND: Many studies have confirmed that electroacupuncture can regulate the body's environment to treat a variety of diseases. However, there are few reports on the mechanism of electroacupuncture therapy for diseases involving skin injury. Transcriptome sequencing can reveal changes in gene expression within cells and the signaling pathways involved. In this study, we used transcriptome sequencing to study the molecular mechanisms by which electroacupuncture promotes the healing of skin lesions. METHODS: A total of 10 SD rats were divided into two groups of 5: a control group and an electroacupuncture treatment group. The wound-healing area was compared between the two groups after 3 and 14 days. Then, mRNA sequencing and bioinformatics were used to analyze the changes in gene expression profiles in skin tissue after electroacupuncture stimulation. RESULTS: (I) The wound area was significantly reduced after 3 and 14 days of electroacupuncture compared with the control group (P<0.05). (II) There was a total of 694 gene expression changes, 496 of which were upregulated and 198 of which were downregulated. Analysis of variable gene-related signaling pathways by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), identified immuneinflammatory response, cell proliferation, tissue remodeling, cell metabolism, graft-versus-host disease, antigen processing and presentation, Th17 cell differentiation, cytokine-cytokine receptor interaction, PPAR signaling pathway, Wnt signaling pathway and other signaling pathways were changed. CONCLUSIONS: Electroacupuncture can promote wound repair, as shown by the changes in gene expression profiles during the healing of skin wounds under electroacupuncture. This study provides a scientific basis that deepens the understanding of the mechanism underlying electroacupuncture.


Assuntos
Eletroacupuntura , Cicatrização/genética , Animais , Ontologia Genética , Modelos Animais , RNA Mensageiro , Ratos , Ratos Sprague-Dawley , Transcriptoma
19.
Zhongguo Gu Shang ; 32(11): 1034-1037, 2019 Nov 25.
Artigo em Chinês | MEDLINE | ID: mdl-31870052

RESUMO

OBJECTIVE: To explore clinical effect of high strength wire under arthroscopy combined with outside anchor nail in treating Meyers McKeever II, III anterior cruciate ligament tibial check point. METHODS: From March 2014 to June 2016, 21 patients with Meyers McKeever II, III avulsion fracture of anterior cruciate ligament tibial check point were treated by high strength wire under arthroscopy combined outside anchor nail. There were 13 males and 8 females aged from 18 to 48 years old with an average of (26.40±5.42) years old. There were 9 cases injured on the left side, and 12 cases on the right side. The courses of disease included sports injuries of 12 cases, falling down injuries of 6 cases, and accident injuries of 3 cases. According to Meyers-McKeever classification, 16 patients were type II and 5 patients were type III. All fractures were fresh, closed and simple injury. The time from injury to operation ranged from 2 to 15 days with an average of (6.20±2.63) d. Lysholm score, IKDC score and the changes of knee mobility were observed and compared before operation and 6 months after operation. RESULTS: Twenty-one patients were followed up for 12 to 24 months with an average of (14.30±3.01) months. Operation time ranged from 40 to 65 min with an average of (45.10±4.82) min, Blood loss ranged from 5 to 15 ml with an average of (10.05±2.75) ml. Lysholm score was improved from 50.29±6.67 before operation to 92.48±2.18 at 6 months after operation. IKDC scores was increased from 47.19±4.57 before operation to 90.71±2.22 at 6 months after operation. Knee joint activity was respectively (83.05±5.33)° and (132.05±7.15)° before operation and 6 months after operation. CONCLUSIONS: High strength wire under arthroscopy combined outside anchor nail in treating Meyers McKeever II, III ACL tibial check point has the advantages of less trauma, firm fixation, and satisfactory clinical effect.


Assuntos
Lesões do Ligamento Cruzado Anterior , Fratura Avulsão , Fraturas da Tíbia , Adolescente , Adulto , Ligamento Cruzado Anterior , Artroscopia , Feminino , Fratura Avulsão/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Técnicas de Sutura , Suturas , Resultado do Tratamento , Adulto Jovem
20.
Artigo em Inglês | MEDLINE | ID: mdl-31467579

RESUMO

The mitogen-activated protein kinase (MAPK) signal transduction pathway plays an important role in the regulation of various diseases, such as cardiovascular and cerebrovascular diseases, and takes part in anti-inflammatory effects, analgesic effects, protection against injury, and maintenance of gastrointestinal functions. Electroacupuncture therapy is an external therapy used in traditional Chinese medicine. By adding external electrical stimulation to traditional acupuncture, the stimulus gets doubled and the therapeutic efficacy gets enhanced accordingly. It combines the benefits of both acupuncture and electrical stimulation. In recent years, some studies have explored the molecular mechanisms of MAPK signal pathways involved with electroacupuncture treatment. Based on these recent studies, this article summarizes the mechanisms of MAPK signal transduction pathways involved with electroacupuncture treatment. This adds great value to the studies of molecular mechanisms of electroacupuncture treatment and also provides an effective reference for its clinical use.

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