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1.
Ann Biomed Eng ; 52(8): 2076-2087, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38679660

RESUMO

The unacceptably high stroke rate associated with HeartMate 3 ventricular assist device (VAD) without signs of adherent pump thrombosis is hypothesized to be the result of the emboli produced by the inflow cannula, that are ingested and ejected from the pump. This in vitro and numerical study aimed to emulate the surface features and supraphysiological shear of a ventricular cannula to provide insight into their effect on thrombogenesis. Human whole blood was perfused at calibrated flow rates in a microfluidic channel to achieve shear rates 1000-7500 s-1, comparable to that experienced on the cannula. The channel contained periodic teeth representative of the rough sintered surface of the HeartMate 3 cannula. The deposition of fluorescently labeled platelets was visualized in real time and analyzed with a custom entity tracking algorithm. Numerical simulations of a multi-constituent thrombosis model were performed to simulate laminar blood flow in the channel. The sustained growth of adherent platelets was observed in all shear conditions ( p <  0.05). However, the greatest deposition was observed at the lower shear rates. The location of deposition with respect to the microfluidic teeth was also found to vary with shear rate. This was confirmed by CFD simulation. The entity tracking algorithm revealed the spatial variation of instances of embolic events. This result suggests that the sintered surface of the ventricular cannula may engender unstable thrombi with a greater likelihood of embolization at supraphysiological shear rates.


Assuntos
Cânula , Simulação por Computador , Trombose , Humanos , Coração Auxiliar , Modelos Cardiovasculares , Plaquetas/metabolismo
2.
Ann Biomed Eng ; 52(4): 1039-1050, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38319505

RESUMO

Our goal was to determine the impact of physiological and pathological shear histories on platelet nucleation and thrombus growth at various local shear rates. We designed and characterized a microfluidic device capable of subjecting platelets to shear histories reaching as high as 6700 s - 1 in a single passage. Time-lapse videos of platelets and thrombi are captured using fluorescence microscopy. Thrombi are tracked, and the degree of thrombosis is evaluated through surface coverage, platelet nucleation maps, and ensemble-averaged aggregate areas and intensities. Surface coverage rates were the lowest when platelets deposited at high shear rates following a pathological shear history and were highest at low shear rates following a pathological shear history. Early aggregate area growth rates were significantly larger for thrombi developing at high shear following physiological shear history than at high shear following a pathological shear history. Aggregate vertical growth was restricted when depositing at low shear following a pathological shear history. In contrast, thrombi grew faster vertically following physiological shear histories. These results show that physiological shear histories pose thrombotic risks via volumetric growth, and pathological shear histories drastically promote nucleation. These findings may inform region-based geometries for biomedical devices and refine thrombosis simulations.


Assuntos
Plaquetas , Trombose , Humanos , Plaquetas/fisiologia , Trombose/patologia
3.
Medicine (Baltimore) ; 103(2): e36774, 2024 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-38215111

RESUMO

BACKGROUND: This systematic review and meta-analysis evaluated the efficacy of electroacupuncture for the treatment of obesity. METHODS: We searched 8 electronic databases for articles published between 2005 and 2021, including only randomized controlled trials (RCTs) in the review. The intervention groups received either electroacupuncture alone or electroacupuncture with standard care, whereas the control groups received sham electroacupuncture, standard care, or no treatment. The primary outcome was the body mass index (BMI), and the secondary outcomes were the body weight (BW), waist circumference (WC), hip circumference, waist-to-hip ratio (WHR), body fat mass, body fat percentage, and adverse effects. Continuous outcome data are presented as mean differences (MDs) with 95% confidence intervals (CIs). RESULTS: This systematic review and meta-analysis included 13 RCTs involving 779 participants. Results revealed that the BMI (MD: -0.98; 95% CI: -1.35 to -0.61), BW (MD: -1.89; 95% CI: -2.97 to -0.80), WC (MD: -2.67; 95% CI: -4.52 to -0.82), and WHR (MD: -0.03; 95% CI: -0.06 to -0.01) were significantly improved in the intervention groups compared with those in the control groups. Adverse effects were reported in 5 studies. The most commonly used acupoint in the abdomen was ST25, whereas the most commonly used acupoints in other regions were ST36 and SP6 for the treatment of obesity. ST25 was the most commonly used acupoint connected by electroacupuncture. CONCLUSION: This systematic review and meta-analysis suggested that electroacupuncture is an effective and safe therapy for simple obesity. To increase the reliability of this study, further detailed, long-term studies should be conducted on the effects of electroacupuncture on obesity.


Assuntos
Eletroacupuntura , Obesidade Mórbida , Humanos , Eletroacupuntura/efeitos adversos , Eletroacupuntura/métodos , Obesidade/terapia , Índice de Massa Corporal , Abdome
4.
Artif Organs ; 47(3): 490-501, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36420933

RESUMO

BACKGROUND: Continuous-flow ventricular assist devices (cfVADs) are implanted in patients with end-stage heart failure to assist with blood circulation. However, VAD implantation is associated with dangerous thrombotic complications. Our goal was to determine the impact of micron and sub-micron scale Ti6Al4V surface roughness on adherent platelet aggregate properties under clinically relevant shear rates. METHODS: We used fluorescence microscopy to visualize platelets in real time as they adhered to Ti6Al4V coupons of varying degrees of roughness, including a smooth control, in microfluidic channels and quantified deposition using an image processing algorithm. We systematically characterized roughness using spatial frequencies to generalize results for more blood-biomaterial contact applications. RESULTS: We observed that on the control and sub-micron rough surfaces, at 1000 s-1 , platelets adhered uniformly on the surface. At 2000 s-1 , we observed small and stably adherent platelet aggregates. At 5500 s-1 , platelet aggregates were large, unstable and interconnected via fibrillar structures. On a surface with micron-scale roughness features, at all three shear rates, platelets deposited in the troughs of the roughened surface, and formed aggregates. Thrombus height at 2000 s-1 and 5500 s-1 was greatest on the roughest surface and lowest on the mirror-finished surface, as indicated by the mean fluorescence intensity. CONCLUSIONS: These results demonstrated that at high shear rates, thrombi form regardless of surface topography at the scales applied. At lower shear rates, micron-scale surface features cause thrombus formation, whereas submicron features result in innocuous platelet adhesion. These findings have implications for manufacturing costs and other considerations.


Assuntos
Trombose , Titânio , Humanos , Titânio/química , Propriedades de Superfície , Plaquetas , Ligas
5.
ASAIO J ; 69(4): 382-390, 2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-36302265

RESUMO

Thrombosis is a major complication that can occur in both blood-contacting devices and regions and in regions of vascular damage. Microfluidic devices are popular templates to model various thrombogenic settings and to assess conditions that lead to bulk channel occlusion. However, area-averaged measurements miss the opportunity to extract real-time information on thrombus evolution and early dynamics of thrombus formation and propagation, which result in late-stage bulk channel occlusion. To clarify these dynamics, we have developed a standalone tracking algorithm that uses consecutive image connectivity and minimal centroid distance mappings to uniquely index all appearing thrombi in fluorescence time-lapse videos http://links.lww.com/ASAIO/A887 , and http://links.lww.com/ASAIO/A888 . This leads to measurements of all individual aggregates that can in turn be studied as ensembles. We applied tracking to fluorescence time-lapse videos http://links.lww.com/ASAIO/A887 , and http://links.lww.com/ASAIO/A888 of thrombosis across both collagen-functionalized substrate and across the surface of a roughened titanium alloy (Ti6Al4V) at a shear rate of 4000 s -1 . When comparing ensemble-averaged measurements to area-averaged metrics, we unveil immediate, steady thrombus growth at early phases on collagen surfaces and unstable thrombus attachment to roughened Ti6Al4V surfaces on Ti6Al4V surfaces. Additionally, we introduce tracked thrombus eccentricity and fluorescence intensity as additional volumetric measures of thrombus growth that relate back to the primary thrombosis mechanism at play. This work advocates for the complementation of surface macrostate metrics with characteristic thrombus microstate growth patterns to accurately predict critical thrombosis events.


Assuntos
Plaquetas , Trombose , Humanos , Trombose/etiologia , Colágeno , Algoritmos
6.
Medicine (Baltimore) ; 101(39): e30773, 2022 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-36181010

RESUMO

INTRODUCTION: This study aimed to propose a protocol to demonstrate the efficacy of Codonopsis lanceolata water extract for the improvement of skeletal muscle mass (SMM) and function (muscle strength or performance function) and its safety compared to a placebo in adults with reduced muscle strength. METHODS AND ANALYSIS: A randomized double-blind placebo-controlled clinical trial was conducted. Participants will be recruited from the Korean Medicine Hospital in South Korea. One hundred and four adults with reduced muscle strength will be randomly assigned a 1:1 ratio to either the experimental or placebo comparator groups. The participants will consume the product corresponding to their assigned group for the following 12 weeks, and efficacy and safety tests will be conducted. This is the first clinical trial of C lanceolata water extract in adults with reduced muscle strength. The results of this study would provide a clinical basis for the efficacy and safety of C lanceolata water extract in patients with sarcopenia. ETHICS AND DISSEMINATION: This trial was approved by the Institutional Review Board (IRB) of Kyung Hee University Korean Medicine Hospital at Gangdong on July 15, 2021 (amendment number: MLB_DDE_H01 [ver. 01]). When a change was made in the clinical trial plan, the IRB reviewed and approved the revised clinical trial plan. The study was registered on the Clinical Research Information Service website on December 3, 2021 (registration number: PRE20211203-003; https://cris.nih.go.kr/cris/search/detailSearch.do?seq=20841&status=1&seq_group=20841&search_page=M). The results of this clinical trial will be reported in the future. Every document related to the clinical trial, such as the electronic case report form, will be recorded and classified by the subject identification code and not by the subject name.


Assuntos
Codonopsis , Sarcopenia , Adulto , Humanos , Método Duplo-Cego , Ensaios Clínicos Controlados Aleatórios como Assunto , Resultado do Tratamento , Água
7.
Medicine (Baltimore) ; 101(9): e29018, 2022 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-35244082

RESUMO

BACKGROUND: Obesity-a public health problem that negatively affects the quality of life-is associated with various diseases, and its prevalence is on the rise. Although drugs and surgical interventions are used to treat obesity, they have adverse effects and limitations. Electroacupuncture is a widely used method for treating obesity in which electrical stimulation is transmitted to the body through acupuncture needles. This systematic review and meta-analysis will evaluate the efficacy of electroacupuncture in treating obesity. METHODS: MEDLINE/PubMed, EMBASE, the Cochrane Central Register of Controlled Trials, 3 Korean databases (Oriental Medicine Advanced Searching Integrated System, ScienceON, and KoreaMed), 1 Japanese database (Citation Information by the National Institute of Informatics), and 1 Chinese database (Chinese National Knowledge Infrastructure) will be searched from their inception to December 2021. The primary outcome will be body mass index, and the secondary outcomes will be body weight, waist and hip circumference, waist-to-hip ratio, body fat percentage, body fat mass, and adverse effects. RESULTS AND CONCLUSION: This systematic review and meta-analysis will provide evidence for efficacy of electroacupuncture as a treatment method for obesity. TRIAL REGISTRATION NUMBER: DOI 10.17605/OSF.IO/YU5XR (https://osf.io/yu5xr).


Assuntos
Eletroacupuntura , Obesidade/terapia , Terapia por Acupuntura , Humanos , Metanálise como Assunto , Qualidade de Vida , Projetos de Pesquisa , Revisões Sistemáticas como Assunto
8.
Sensors (Basel) ; 22(1)2021 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-35009717

RESUMO

Studies on deep-learning-based behavioral pattern recognition have recently received considerable attention. However, if there are insufficient data and the activity to be identified is changed, a robust deep learning model cannot be created. This work contributes a generalized deep learning model that is robust to noise not dependent on input signals by extracting features through a deep learning model for each heterogeneous input signal that can maintain performance while minimizing preprocessing of the input signal. We propose a hybrid deep learning model that takes heterogeneous sensor data, an acceleration sensor, and an image as inputs. For accelerometer data, we use a convolutional neural network (CNN) and convolutional block attention module models (CBAM), and apply bidirectional long short-term memory and a residual neural network. The overall accuracy was 94.8% with a skeleton image and accelerometer data, and 93.1% with a skeleton image, coordinates, and accelerometer data after evaluating nine behaviors using the Berkeley Multimodal Human Action Database (MHAD). Furthermore, the accuracy of the investigation was revealed to be 93.4% with inverted images and 93.2% with white noise added to the accelerometer data. Testing with data that included inversion and noise data indicated that the suggested model was robust, with a performance deterioration of approximately 1%.


Assuntos
Atividades Humanas , Redes Neurais de Computação , Acelerometria , Bases de Dados Factuais , Humanos
9.
Langmuir ; 34(19): 5581-5591, 2018 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-29676917

RESUMO

Stimuli-responsive nanoparticles at fluid interfaces offer great potential for realizing on-demand and controllable self-assembly that can benefit various applications. Here, we conducted electrostatic dissipative particle dynamics simulations to provide a fundamental understanding of the microstructure and interfacial dynamics of responsive nanoparticle monolayers at a water-oil interface. The model nanoparticle is functionalized with polyelectrolytes to render the pH sensitivity, which permits further manipulation of the monolayer properties. The monolayer structure was analyzed in great detail through the density and electric field distributions, structure factor, and Voronoi tessellation. Even at a low surface coverage, a continuous disorder-to-order phase transition was observed when the particle's degree of ionization increases in response to pH changes. The six-neighbor particle fraction and bond orientation order parameter quantitatively characterize the structural transition induced by long-range electrostatic interactions. Adding salt can screen the electrostatic interactions and offer additional control on the monolayer structure. The detailed dynamics of the monolayer in different states was revealed by analyzing mean-squared displacements, in which different diffusion regimes were identified. The self-diffusion of individual particles and the collective dynamics of the whole monolayer were probed and correlated with the structural transition. Our results provide deeper insight into the dynamic behavior of responsive nanoparticle surfactants and lay the groundwork for bottom-up synthesis of novel nanomaterials, responsive emulsions, and microdroplet reactors.

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