Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
1.
Artigo em Inglês | MEDLINE | ID: mdl-35022681

RESUMO

OBJECTIVES: This study aimed to investigate the impact of mechanical factors at baseline on the patency of a restorative conduit for coronary bypass grafts in an ovine model at serial follow-up up to 1 year. METHODS: The analyses of 4 mechanical factors [i.e. bending angle, superficial wall strain and minimum and maximum endothelial shear stress (ESS)] were performed in 3D graft models reconstructed on baseline (1-month) angiograms frame by frame by a core laboratory blinded for the late follow-up. The late patency was documented by Quantitative Flow Ratio (QFR®) that reflects the physiological status of the graft. The correlation between 4 mechanical factors and segmental QFR (△QFR) were analysed on 10 equal-length segments of each graft. RESULTS: A total of 69 graft geometries of 7 animals were performed in the study. The highest △QFR at 12 months was colocalized in segments of the grafts with the largest bending angles at baseline. Higher △QFR at 3 months were both at the anastomotic ends and were colocalized with the highest superficial wall strain at baseline. High baseline ESS was topographically associated with higher △QFR at the latest follow-up. Correlations of minimum and maximum ESS with △QFR at 3 months were the strongest among these parameters (ρ = 0.30, 95% CI [-0.05 to 0.56] and ρ = 0.27, 95% CI [-0.05 to 0.54], respectively). CONCLUSIONS: Despite the limited number of grafts, this study suggests an association between early abnormal mechanical factors and late flow metrics of the grafts. The understanding of the mechanical characteristics could help to improve this novel conduit.

2.
Carbohydr Polym ; 278: 118935, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34973753

RESUMO

It is an urgent task to exploit effective antimicrobial agents due to the rise of drug-resistant pathogens. Herein, antimicrobial quaternized chitosan/Ag composite nanogels (QCS/Ag CNGs) with tunable properties were fabricated through inverse miniemulsion technique with a high encapsulation efficiency of NH2-Ag nanoparticles (NPs). The QCS/Ag CNGs possess superior broad-spectrum antimicrobial activity and low biotoxicity, via synergistic sterilization of Ag NPs and QCS. Furthermore, the NH2-Ag NPs were chemically linked to the QCS matrix through Schiff base reactions, and the QCS/Ag CNGs have reactive groups, making it possible to obtain durable antibacterial cotton fabrics. Thus, QCS/Ag CNGs modified cotton fabrics exhibited laundering durability of antimicrobial effect after 100 washing cycles without sacrificing other inherent properties of cotton fabrics. Our study provides a facile and controllable method to construct polymer/inorganic CNGs to address the urgent need for antibacterial agents/fabrics.


Assuntos
Antibacterianos/farmacologia , Quitosana/farmacologia , Fibra de Algodão , Nanopartículas Metálicas/química , Nanogéis/química , Prata/farmacologia , Antibacterianos/síntese química , Antibacterianos/química , Candida albicans/efeitos dos fármacos , Configuração de Carboidratos , Quitosana/química , Emulsões , Escherichia coli/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Prata/química , Staphylococcus aureus/efeitos dos fármacos
3.
Catheter Cardiovasc Interv ; 99(2): 424-432, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-33565719

RESUMO

OBJECTIVE: Present bench study aimed to evaluate whether technical characteristics of Fantom Encore® bioresorbable scaffold (BRS) allow to perform proximal optimization/side branch dilation/proximal optimization (POT-SB-POT) technique, as an adequate solution for bifurcation percutaneous coronary intervention. METHODS: Two Fantom Encore® BRS platforms (small with 3.0 mm nominal diameter, n = 7; and large with 3.5 mm nominal diameter, n = 7) were evaluated in bench models, which were designed according to Finet-law and fitted to nominal scaffold diameter in the distal main branch (MB) and fitted to indicated maximal expansion capacity in the proximal main branch (MB). Results were evaluated by (a) fluoroscopy, (b) optical coherence tomography (OCT) and (c) micro-computed tomography (µCT). RESULTS: All procedures were performed according to the protocol. Careful review of the fluoroscopic loops by an independent operator did not reveal any strut fracture or major deformation. By OCT the overall rate of perfectly apposed struts in the bifurcation area was 15 ± 6% after SB opening, that increased significantly but remained low with 22 ± 9% after final POT (p = .001). Compared to SB ballooning alone, significant benefit of final POT was found in rate of perfect apposition in the proximal MB (15 ± 12% vs. 26 ± 15%, respectively; p = .017) and at the abostial side of polygon of confluence (7 ± 9% vs. 16 ± 13%, respectively; p = .005). µCT analysis revealed a single strut fracture in one case with the small platform, while four cases showed single or multiple strut fractures with the large platform. CONCLUSION: The mechanical characteristics of the device are not suitable for use of Conventional techniques for bifurcation PCI such as POT-SB-POT. The use of Fantom Encore® BRS for bifurcation PCI with relevant SB should not be encouraged.


Assuntos
Angioplastia Coronária com Balão , Doença da Artéria Coronariana , Intervenção Coronária Percutânea , Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/terapia , Vasos Coronários/diagnóstico por imagem , Humanos , Modelos Cardiovasculares , Intervenção Coronária Percutânea/efeitos adversos , Desenho de Prótese , Tomografia de Coerência Óptica , Resultado do Tratamento , Microtomografia por Raio-X
4.
EuroIntervention ; 18(1): 83-90, 2022 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-34930716

RESUMO

BACKGROUND: While radial stent deformation has been thoroughly investigated, data on longitudinal deformation are scarce. AIMS: The aim of the study was to describe longitudinal stent deformation associated with the proximal optimisation technique (POT). METHODS: Longitudinal stent deformation was assessed by bench testing and by clinical evaluation. Bench testing was performed in silicone models using 3.00 (n=15) and 3.50 mm (n=14) stent platforms. After deployment, stents were sequentially post-dilated in the proximal main branch up to 5.50 mm, in increments of 0.50 mm, in order to simulate a spectrum of overexpansion. Stent length was redefined by optical coherence tomography (OCT) after each step. Clinical data were collected retrospectively from OCT-guided bifurcation percutaneous coronary intervention cases. RESULTS: In bench tests, POT has led to significant stent elongation in all cases. The magnitude of elongation was comparable between the 3.00 and the 3.50 mm stent platforms, with 0.86±0.74 mm vs 0.86±0.73 mm, respectively (p=0.71), per 0.5 mm overexpansion. For 3.00 mm stent platforms, maximal elongation was 4.31±1.47 mm after up to 5.5 mm overexpansion. For 3.50 mm platforms, maximal elongation was 2.87±0.94 mm after up to 5.5 mm overexpansion. Thirty-six clinical cases were analysed, of which 22 (61%) were performed in the distal left main. Post-dilation was performed with 0.98±0.36 mm absolute overexpansion, resulting in 2.22±1.35 mm elongation, as compared to nominal stent length. CONCLUSIONS: Overexpansion by POT results in proximal stent elongation. This has to be considered once the stent length is selected and the stent is positioned, especially in the left main stem, where proximal overexpansion is marked and accurate ostial landing is critical.

5.
Front Cardiovasc Med ; 8: 667310, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34222366

RESUMO

A novel method for four-dimensional superficial wall strain and stress (4D-SWS) is derived from the arterial motion as pictured by invasive coronary angiography. Compared with the conventional finite element analysis of cardiovascular biomechanics using the estimated pulsatile pressure, the 4D-SWS approach can calculate the dynamic mechanical state of the superficial wall in vivo, which could be directly linked with plaque rupture or stent fracture. The validation of this approach using in silico models showed that the distribution and maximum values of superficial wall stress were similar to those calculated by conventional finite element analysis. The in vivo deformation was validated on 16 coronary arteries, from the comparison of centerlines predicted by the 4D-SWS approach against the actual centerlines reconstructed from angiograms at a randomly selected time-point, which demonstrated a good agreement of the centerline morphology between both approaches (scaling: 0.995 ± 0.018 and dissimilarity: 0.007 ± 0.014). The in silico vessel models with softer plaque and larger plaque burden presented more variation in mean lumen diameter and resulted in higher superficial wall stress. In more than half of the patients (n = 16), the maximum superficial wall stress was found at the proximal lesion shoulder. Additionally, in three patients who later suffered from acute coronary syndrome, the culprit plaque rupture sites co-localized with the site of highest superficial wall stress on their baseline angiography. These representative cases suggest that angiography-based superficial wall dynamics have the potential to identify coronary segments at high-risk of plaque rupture and fracture sites of implanted stents. Ongoing studies are focusing on identifying weak spots in coronary bypass grafts, and on exploring the biomechanical mechanisms of coronary arterial remodeling and aneurysm formation. Future developments involve integration of fast computational techniques to allow online availability of superficial wall strain and stress in the catheterization laboratory.

6.
J Cardiovasc Electrophysiol ; 32(6): 1646-1654, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33783902

RESUMO

INTRODUCTION: We aimed to investigate whether a modified implantation method facilitating a fully open umbrella can reduce the pericardial effusion/pericardial tamponade (PE/PT) rate after left atrial appendage closure (LAAC) with the LAmbre device compared with the conventional method (CM) in patients with non-valvular atrial fibrillation (NVAF). METHODS AND RESULTS: Patients with NVAF who received either isolated LAAC or combined catheter ablation and LAAC using the LAmbre device at the First Affiliated Hospital of Wenzhou Medical University from January 2018 to December 2019 were enrolled. CM was used for device implantation in the initial 59 patients, while a modified method (MM) was used in the remaining 165 patients. Successful implantation was achieved in 98.3% of patients in the CM group and 98.8% in the MM group. A higher rate of a fully open umbrella (98.8% vs. 69%, p < .001), less requirement for recapture (46% vs. 62.1%, p = .036), and a lower incidence of delayed PE/PT (1.2% vs. 8.6%, p = .005) were found in the MM group compared with the CM group. All of the five delayed PT events occurred in patients with combined treatment. An umbrella that was not fully open was the only factor associated with delayed PE/PT events in a multivariable Cox model. CONCLUSIONS: LAAC with the LAmbre device using an MM significantly increases the rate of a fully open umbrella and decreases the requirement for recapture and the incidence of delayed PE/PT. This method is more effective in patients with combined treatment.


Assuntos
Apêndice Atrial , Fibrilação Atrial , Procedimentos Cirúrgicos Cardíacos , Derrame Pericárdico , Acidente Vascular Cerebral , Apêndice Atrial/diagnóstico por imagem , Apêndice Atrial/cirurgia , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/cirurgia , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Humanos , Derrame Pericárdico/diagnóstico por imagem , Derrame Pericárdico/etiologia , Resultado do Tratamento
7.
Expert Rev Med Devices ; 18(4): 351-365, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33739213

RESUMO

Introduction: The first-generation bioresorbable scaffolds (BRSs) had a large strut profile to compensate for the insufficient radial strength of bioresorbable polymer materials, resulting in higher scaffold thrombosis rates than conventional drug-eluting stents. To improve the clinical safety and efficacy, the new generation BRSs have been improved by optimal structure design, post-processing of bioresorbable polymer materials, or altering bioresorbable metallic alloys.Areas covered: This review summarizes the lessons learned from the first-generation BRS, updates the clinical outcomes of trials evaluating ABSORB bioresorbable vascular scaffold at long-term and bioresorbable metallic alloy-based devices, and examines recent outcomes of BRS treated in STEMI patients. This review also provides an overview of the current clinical data of seven BRSs manufactured in Asia, and of the BRSs extended application in other clinical arenas.Expert opinion: Drawbacks of the first-generation BRSs need to be addressed by the next generation of these stents with novel materials and technologies. Clinical research, including randomized controlled trials, are required to further evaluate BRSs application in coronary artery disease. The encouraging results of BRSs innovation applied in the peripheral arteries and gastrointestinal tracts support other potential clinical applications of BRS technology.


Assuntos
Implantes Absorvíveis , Doença da Artéria Coronariana/terapia , Tecidos Suporte/química , Ensaios Clínicos como Assunto , Humanos , Fenômenos Mecânicos , Resultado do Tratamento
8.
Langmuir ; 37(3): 1297-1305, 2021 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-33428403

RESUMO

The precise and effective generation of micron-sized droplets is one of the most common and important issues for droplet-based microfluidics. Active droplet generation makes use of additional energy input in promoting interfacial instabilities for droplet generation. Here, we report a new technique for the active generation of femtoliter droplets in microfluidic systems using confined interfacial vibration (CIV). The CIV is formed at the orifice of a traditional inkjet nozzle first by pushing the liquid out and then pulling it back. Droplets are pinched off during the withdrawal process, and this is different from the current active droplet generation techniques, which only monodirectionally push the liquid out. Droplets with radius ranging from ca. 1 to 28 µm can be actively generated by CIV at an orifice with radius 30 µm, distinguishing from conventional active generation techniques in which the droplets are always comparable or slightly bigger than the orifice. Experimental results showed that the droplet volume can be customized by controlling the intensity of the CIV. The inherent digital nature of the inkjet technique enables easy and precise regulating of the droplet volume, making it seamlessly compatible with the digital microfluidic systems.

9.
Future Cardiol ; 17(4): 593-607, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33258702

RESUMO

Drug-eluting stents (DES) have been developed over recent decades and the implantation of DES is the standard of care in contemporary percutaneous coronary intervention for patients with coronary artery disease. The MiStent sirolimus-eluting stent has several unique features; ultra-thin (64 µm) struts, a bioresorbable polymer and a controlled drug release from microcrystalline sirolimus as a reservoir embedded in the vessel wall. Results of recent clinical trials demonstrated the potential performance of this state-of-the-art DES. In the present review, we provide an overview of the development of DES, in particular the design and performance of the novel MiStent sirolimus-eluting stent from technological and clinical points of view and discuss the potentials of this new type of DES.


Assuntos
Doença da Artéria Coronariana , Stents Farmacológicos , Intervenção Coronária Percutânea , Implantes Absorvíveis , Doença da Artéria Coronariana/tratamento farmacológico , Doença da Artéria Coronariana/cirurgia , Humanos , Desenho de Prótese , Sirolimo , Stents , Tecnologia , Resultado do Tratamento
10.
Nanoscale ; 11(47): 22734-22742, 2019 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-31763653

RESUMO

Hydrogen production by water electrolysis is a common strategy for the development of renewable energy. However, meeting the industrial requirement for high efficiency and low cost is difficult to achieve with the existing methods. Herein, a novel and simple synthesis route for a dendritic self-supported electrode consisting of oxygen vacancy-rich NiO embedded within ultrathin 2D/3D nanostructures (NiO-Vo@2D/3D NS@DSE) for overall water splitting is developed for the first time. Based on the simple compound synthesis by jet electrodeposition and in situ acid etching, 2D nanosheets adhering uniformly to 3D nanospheres are successfully obtained on the dendritic self-supported skeleton surface. The experiments and density functional calculations illustrate that this electrode integrates the advantages including numerous active sites, intrinsic catalytic activity, good electrical conductivity, and outstanding reaction kinetic performance. Moreover, NiO-Vo@2D/3D NS@DSE shows excellent oxygen evolution reaction and hydrogen evolution reaction activities in 1 M KOH with overpotentials of 230 and 51 mV at 10 mA cm-2, respectively. Additionally, the electrode, as an alkali-electrolyzer, displays a potential of 1.51 V at 10 mA cm-2 with favorable stability that is superior to that of IrO2@nickel foam (NF)//Pt/C@NF (1.62 V). Surprisingly, the cost of NiO-Vo@2D/3D NS@DSE is ≈1/120 of the price of noble electrocatalysts with the same mass. This research opens up a new pathway for the design of bifunctional electrocatalysts.

11.
Int J Cardiovasc Imaging ; 35(9): 1563-1572, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31053979

RESUMO

The measurement of fractional flow reserve (FFR) and superficial wall stress (SWS) identifies inducible myocardial ischemia and plaque vulnerability, respectively. A simultaneous evaluation of both FFR and SWS is still lacking, while it may have a major impact on therapy. A new computational model of one-way fluid-structure interaction (FSI) was implemented and used to perform a total of 54 analyses in virtual coronary lesion models, based on plaque compositions, arterial remodeling patterns, and stenosis morphologies under physiological conditions. Due to a greater lumen dilation and more induced strain, FFR in the lipid-rich lesions (0.81 ± 0.15) was higher than that in fibrous lesions (0.79 ± 0.16, P = 0.001) and calcified lesions (0.79 ± 0.16, P = 0.001). Four types of lesions were further defined, based on the combination of cutoff values for FFR (0.80) and maximum relative SWS (30 kPa): The level of risk increased from (1) plaques with mild-to-moderate stenosis but negative remodeling for lipid-rich (Type A: non-ischemic, stable) to (2) lipid-rich plaques with mild-to-moderate stenosis and without-to-positive remodeling (Type B: non-ischemic, unstable) or plaques with severe stenosis but negative remodeling for lipid-rich (Type C: ischemic, stable) to (3) lipid-rich plaques with severe stenosis and without-to-positive remodeling (Type D: ischemic, unstable). The analysis of FSI to simultaneously evaluate inducible myocardial ischemia and plaque stability may be useful to identify coronary lesions at a high risk and to ultimately optimize treatment. Further research is warranted to assess whether a more aggressive treatment may improve the prognosis of patients with non-ischemic, intermediate, and unstable lesions.


Assuntos
Cateterismo Cardíaco , Doença da Artéria Coronariana/diagnóstico , Estenose Coronária/diagnóstico por imagem , Vasos Coronários/patologia , Vasos Coronários/fisiopatologia , Reserva Fracionada de Fluxo Miocárdico , Hemodinâmica , Modelos Cardiovasculares , Placa Aterosclerótica , Fenômenos Biomecânicos , Doença da Artéria Coronariana/patologia , Doença da Artéria Coronariana/fisiopatologia , Doença da Artéria Coronariana/terapia , Estenose Coronária/patologia , Estenose Coronária/fisiopatologia , Estenose Coronária/terapia , Humanos , Valor Preditivo dos Testes , Prognóstico , Reprodutibilidade dos Testes , Medição de Risco , Fatores de Risco , Ruptura Espontânea , Índice de Gravidade de Doença
13.
Int J Cardiovasc Imaging ; 34(6): 849-861, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29397475

RESUMO

Cyclic biomechanical stress at the lumen-intima interface plays a crucial role in the rupture of coronary plaque. We performed a comprehensive assessment of a novel angiography-based method for four-dimensional (4D) dynamic assessment of superficial wall stress (SWS) and deformation with a total of 32 analyses in virtual stenosis models with equal lumen dimensions and 16 analyses in human coronary arteries in vivo. The in silico model analyses demonstrated that the SWS, derived by the proposed global displacement method without knowledge of plaque components or blood pressure, was comparable with the result calculated by traditional finite element method. Cardiac contraction-induced vessel deformation increased SWS. Softer plaque and positive arterial remodeling, associated with a greater plaque burden, showed more variation in mean lumen diameter within the cardiac cycle and resulted in higher SWS. In vivo patient analyses confirmed the accuracy of computed superficial wall deformation. The centerlines predicted by our method at random selected time instant matched well with the actual one in angiograms by Procrustes analysis (scaling: 0.995 ± 0.018; dissimilarity: 0.007 ± 0.014). Over 50% of the maximum SWS occurred at proximal plaque shoulders. This novel 4D approach could be successfully to predict superficial wall deformation of coronary artery in vivo. The dynamic SWS might be more realistic to evaluate the risk of plaque rupture.


Assuntos
Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/fisiopatologia , Estenose Coronária/diagnóstico por imagem , Estenose Coronária/fisiopatologia , Vasos Coronários/diagnóstico por imagem , Vasos Coronários/fisiopatologia , Placa Aterosclerótica/diagnóstico por imagem , Placa Aterosclerótica/fisiopatologia , Fenômenos Biomecânicos , Simulação por Computador , Angiografia Coronária , Análise de Elementos Finitos , Hemodinâmica , Humanos , Modelos Cardiovasculares , Projetos Piloto , Estudos Prospectivos , Ruptura , Estresse Mecânico
14.
Curr Pharm Des ; 24(4): 451-464, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29283055

RESUMO

Angiogenesis is described as a sprouting and growth process of new blood vessels from pre-existing vasculature. The relationship between angiogenesis and coronary artery disease (CAD) is double-sided. On one hand, angiogenesis within plaques is responsible for facilitating the growth and vulnerability of plaques by causing intraplaque hemorrhage and inflammatory cell influx, and overabundance of erythrocytes and inflammatory cells within a plaque probably causes plaque rupture, further leading to acute coronary syndrome. Therefore, inhibiting intraplaque angiogenesis has been considered as a potential therapeutic target for CAD. On the other hand, aiming at improving reperfusion to the ischemic myocardium in patients with CAD, angiogenesis promoting has been utilized as a therapeutic approach to expand myocardial microvascular network. Current strategies include direct administration of angiogenic growth factors (protein therapy), promoting angiogenic genes expression in vivo (gene therapy), and delivering stem cells (cell therapy) or exosomes (cell free therapy). This article will start by clarifying the basic concept of angiogenesis, interpret the mechanism of excessive intraplaque angiogenesis in atherosclerosis, and discuss its role in the growth and vulnerability of plaques. Then we will focus on the four distinct strategies of therapeutic angiogenesis. Despite promising animal studies and smallscale clinical trials of therapeutic angiogenesis in patients with ischemic heart disease, investigations have far not shown definite evidence of clinical efficacy. Hence, while acknowledging future work that remains to be done to validate the clinical results, we reviewed the critical challenges in this arena and highlighted the exciting progress that has occurred recently.


Assuntos
Aterosclerose/terapia , Doença da Artéria Coronariana/terapia , Exossomos , Terapia Genética , Peptídeos e Proteínas de Sinalização Intercelular/uso terapêutico , Células-Tronco , Aterosclerose/fisiopatologia , Doença da Artéria Coronariana/fisiopatologia , Humanos
15.
Front Aging Neurosci ; 9: 90, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28420984

RESUMO

Objective: To explore serum caveolin-3 (Cav-3) levels in patients with atrial fibrillation (AF) and to evaluate the role of Cav-3 as a biomarker for AF and incident heart failure (HF). Methods: Three hundred and five patients were enrolled in the study and divided into three groups: sinus rhythm (Group SR), paroxysmal AF (Group paAF), and persistent AF (Group peAF). Serum Cav-3 concentrations were measured by enzyme-linked immunosorbent assay at baseline. Clinical characteristics, and laboratory data were collected during hospitalization, and a follow-up of 12-months was carried out. Results: Serum Cav-3 concentrations were significantly decreased on the Group SR and the highest concentrations of Cav-3 in patients were found on the Group peAF (516.7 ± 274.0 vs. 609.3 ± 287.0 vs. 688.3 ± 264.6 ng/L, P < 0.05). Left atrial diameter (LAD) in the Group peAF was significantly higher than in the Group paAF, and the Group SR had significantly lower LAD than the Group paAF and Group peAF. The risks of new-onset HF in the Group SR, Group paAF, and Group peAF were 8.1, 14.5, and 28.6%, respectively. There was a significant difference between the Group peAF and the other two groups. Serum Cav-3 concentrations were trisected in AF participants (lower tertile: ≤498, middle tertile: >498-703, upper tertile: ≥703). In further tertile studies, subjects in the lower tertile of Cav-3 concentrations were more likely to become paroxysmal AF and had much lower LAD (P < 0.05). And in the middle and upper tertiles, participants with AF tended to suffer from HF compared to the lower group (P < 0.05). Conclusion: We provide evidence that Cav-3 has a significant meaning in AF patients. The levels of Cav-3 may be related to the LAD and new-onset HF.

16.
EuroIntervention ; 13(9): e1099-e1103, 2017 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-28262624

RESUMO

AIMS: Repetitive, fluctuating stress is an important biomechanical mechanism that underlies the rupture of atherosclerotic plaques. We developed a novel coronary angiography-based method for in vivo four-dimensional analysis of dynamic superficial wall stress (SWS) in coronary plaques and applied it for the first time in two clinical cases. Our aim was to investigate the potential relationship between dynamic stress concentration at baseline and plaque rupture during acute coronary syndrome (ACS) several months later. METHODS AND RESULTS: Three-dimensional angiographic reconstructions of the interrogated arteries were performed at several phases of the cardiac cycle, followed by finite element analysis to obtain the dynamic SWS data. The peak stress at baseline was found at the distal and proximal lesion longitudinal shoulders, being 121.8 kPa and 98.0 kPa, respectively. Intriguingly, in both cases, the sites with the highest SWS concentration at baseline co-registered with the location of plaque rupture during ACS, respectively six and 18 months after the baseline angiographic assessment. CONCLUSIONS: A novel angiography-based analysis method for four-dimensional evaluation of dynamic SWS was feasible for investigating plaque biomechanical behaviour in vivo. Initial experience suggests that this technique could be useful in exploring mechanisms of future plaque rupture.


Assuntos
Angiografia Coronária/métodos , Doença da Artéria Coronariana/diagnóstico por imagem , Placa Aterosclerótica/diagnóstico por imagem , Idoso , Humanos , Masculino , Pessoa de Meia-Idade , Estresse Mecânico
18.
ISA Trans ; 64: 174-183, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27282519

RESUMO

Bayesian network (BN) is a widely used formalism for representing uncertainty in probabilistic systems and it has become a popular tool in reliability engineering. The GO-FLOW method is a success-oriented system analysis technique and capable of evaluating system reliability and risk. To overcome the limitations of GO-FLOW method and add new method for BN model development, this paper presents a novel approach on constructing a BN from GO-FLOW model. GO-FLOW model involves with several discrete time points and some signals change at different time points. But it is a static system at one time point, which can be described with BN. Therefore, the developed BN with the proposed method in this paper is equivalent to GO-FLOW model at one time point. The equivalent BNs of the fourteen basic operators in the GO-FLOW methodology are developed. Then, the existing GO-FLOW models can be mapped into equivalent BNs on basis of the developed BNs of operators. A case of auxiliary feedwater system of a pressurized water reactor is used to illustrate the method. The results demonstrate that the GO-FLOW chart can be successfully mapped into equivalent BNs.

19.
Mol Med Rep ; 11(6): 4678-84, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25673156

RESUMO

Primary percutaneous coronary intervention, or thombolytic therapy, provides effective myocardial blood reconstruction in patients with acute myocardial infarction to reduce acute myocardial ischemic injury. However, reperfusion can itself induce cardiomyocyte death, termed myocardial reperfusion injury (I/R). Hypoxia/reoxygenation (H/R) induces apoptosis and excessive autophagy among cardiomyocytes, leading to cell death. The present study investigated the effect of curcumin, a natural extract from Curcuma longa, on these two cellular processes in H9c2 myocytes. The levels of cellular apoptosis and autophagy were found to be upregulated in the H9c2 myocytes during H/R and were correlated with a reduced rate of cell survival. However, curcumin significantly suppressed the levels of H/R­induced apoptosis (expression of annexin V) and autophagy (LC3B­II/LC3B­I ratio) in the H9c2 myocytes and promoted cell survival. Additionally, the expression of B­cell lymphoma 2 (Bcl­2) was significantly downregulated and the expression levels of Bcl­2­associated X protein, beclin­1, Bcl­2/adenovirus E1B 19 kDa interacting protein 3 (BNIP3) and silent information regulation 1 (SIRT1) were significantly upregulated in myocytes following H/R injury. These effects on the expression of these proteins were reversed by curcumin treatment. These findings suggested that the protective effect of curcumin against H/R injury in the H9c2 myocytes was through the inhibition of apoptosis and autophagy by inducing the expression of Bcl­2 and inhibiting the expression levels of Bax, beclin­1, BNIP3 and SIRT1. Therefore, curcumin may offer a promising therapeutic approach for the treatment of cardiomyocyte injury resulting from I/R.


Assuntos
Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Curcumina/farmacologia , Proteínas Reguladoras de Apoptose/metabolismo , Proteína Beclina-1 , Hipóxia Celular , Linhagem Celular , Regulação para Baixo/efeitos dos fármacos , Humanos , Proteínas de Membrana/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Miócitos Cardíacos/citologia , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Oxigênio/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Sirtuína 1/metabolismo , Regulação para Cima/efeitos dos fármacos , Proteína X Associada a bcl-2/metabolismo
20.
Appl Bionics Biomech ; 2015: 475261, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-27019584

RESUMO

Background. The biomechanical effect of two implants, namely, proximal femoral nail antirotation for Asia (PFNA-II) and Expert Asian Femoral Nail (A2FN), for treating subtrochanteric fracture during healing stages, is still unclear. Methods. A 3D finite element model of an intact femur was constructed and validated. The fractured and postoperative models were accordingly produced. The postoperative models were loaded with the peak joint forces during gait for the soft and hard callus stages. The effects of stress distribution on the implants, femoral head and callus, and the deformation of the proximal femur were examined. Results. Both implants showed similar biomechanical effect in two healing stages. As the healing duration increased, the von Mises stress of two implants and the tensile stress of the femoral head decreased, whereas the compressive stress of the femoral head increased. However, the PFNA-II operation resulted in higher stress on the implant, lower stress on the proximal femur, and lower compressive stress and higher tensile stress on the callus than A2FN operation. Conclusions. The A2FN implant may provide a biomechanically superior construct for subtrochanteric fracture healing. However, the upper screw of the A2FN implant may be more likely to be loose in the healing process.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...