RESUMO
Biomolecular condensates formed via liquid-liquid phase separation (LLPS) are increasingly being shown to play major roles in cellular self-organization dynamics in health and disease. It is well established that macromolecular crowding has a profound impact on protein interactions, particularly those that lead to LLPS. Although synthetic crowding agents are used during in vitro LLPS experiments, they are considerably different from the highly crowded nucleo-/cytoplasm and the effects of in vivo crowding remain poorly understood. In this work, we applied computational modeling to investigate the effects of macromolecular crowding on LLPS. To include biologically relevant LLPS dynamics, we extended the conventional Cahn-Hilliard model for phase separation by coupling it to experimentally derived macromolecular crowding dynamics and state-dependent reaction kinetics. Through extensive field-theoretic computer simulations, we show that the inclusion of macromolecular crowding results in late-stage coarsening and the stabilization of relatively smaller condensates. At a high crowding concentration, there is an accelerated growth and late-stage arrest of droplet formation, effectively resulting in anomalous labyrinthine morphologies akin to protein gelation observed in experiments. These results not only elucidate the crowder effects observed in experiments, but also highlight the importance of including state-dependent kinetics in LLPS models, and may help in designing further experiments to probe the intricate roles played by LLPS in self-organization dynamics of cells.
Assuntos
Extração Líquido-Líquido/métodos , Substâncias Macromoleculares/química , Substâncias Macromoleculares/isolamento & purificação , Algoritmos , Humanos , Cinética , Modelos TeóricosRESUMO
BACKGROUND: Image quality assessment method of photoacoustic tomography has not been completely standardized yet. Due to the combined nature of photonic signal generation and ultrasonic signal transmission in biological tissue, neither optical nor ultrasonic traditional methods can be used without modification. An optical resolution measurement technique was investigated for its feasibility for resolution measurement of photoacoustic tomography. METHODS: A patterned thin metal film deposited on silica glass provides high contrast in optical imaging due to high reflectivity from the metal film and high transmission from the glass. It provides high contrast when it is used for photoacoustic tomography because thin metal film can absorb pulsed laser energy. An US Air Force 1951 resolution target was used to generate patterned photoacoustic signal to measure the lateral resolution. Transducer with 2.25 MHz bandwidth and a sample submerged in water and gelatinous block were tested for lateral resolution measurement. RESULTS: Photoacoustic signal generated from a thin metal film deposited on a glass can propagate along the surface or through the surrounding medium. First, a series of experiments with tilted sample confirmed that the measured photoacoustic signal is what is propagating through the medium. Lateral resolution of the photoacoustic tomography system was successfully measured for water and gelatinous block as media: 0.33 mm and 0.35 mm in water and gelatinous material, respectively, when 2.25 MHz transducer was used. Chicken embryo was tested for biomedical applications. CONCLUSIONS: A patterned thin metal film sample was tested for its feasibility of measuring lateral resolution of a photoacoustic tomography system. Lateral resolutions in water and gelatinous material were successfully measured using the proposed method. Measured resolutions agreed well with theoretical values.
Assuntos
Metais , Técnicas Fotoacústicas/métodos , Tomografia/métodos , Vidro/química , Metais/química , Técnicas Fotoacústicas/instrumentação , Controle de Qualidade , Dióxido de Silício/química , Som , Tomografia/instrumentação , Transdutores , Água/químicaRESUMO
BACKGROUND: Radiological scoring methods such as colon transit time (CTT) have been widely used for the assessment of bowel motility. However, these radiograph-based methods need cumbersome radiological instruments and their frequent exposure to radiation. Therefore, a non-invasive estimation algorithm of bowel motility, based on a back-propagation neural network (BPNN) model of bowel sounds (BS) obtained by an auscultation, was devised. METHODS: Twelve healthy males (age: 24.8 ± 2.7 years) and 6 patients with spinal cord injury (6 males, age: 55.3 ± 7.1 years) were examined. BS signals generated during the digestive process were recorded from 3 colonic segments (ascending, descending and sigmoid colon), and then, the acoustical features (jitter and shimmer) of the individual BS segment were obtained. Only 6 features (J1, 3, J3, 3, S1, 2, S2, 1, S2, 2, S3, 2), which are highly correlated to the CTTs measured by the conventional method, were used as the features of the input vector for the BPNN. RESULTS: As a results, both the jitters and shimmers of the normal subjects were relatively higher than those of the patients, whereas the CTTs of the normal subjects were relatively lower than those of the patients (p < 0.01). Also, through k-fold cross validation, the correlation coefficient and mean average error between the CTTs measured by a conventional radiograph and the values estimated by our algorithm were 0.89 and 10.6 hours, respectively. CONCLUSIONS: The jitter and shimmer of the BS signals generated during the peristalsis could be clinically useful for the discriminative parameters of bowel motility. Also, the devised algorithm showed good potential for the continuous monitoring and estimation of bowel motility, instead of conventional radiography, and thus, it could be used as a complementary tool for the non-invasive measurement of bowel motility.
Assuntos
Algoritmos , Motilidade Gastrointestinal , Redes Neurais de Computação , Adulto , Auscultação , Colo/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Fenômenos Fisiológicos Musculoesqueléticos , Análise de Regressão , Processamento de Sinais Assistido por Computador , Adulto JovemRESUMO
We investigated a high-precision optical method for measuring the thickness of biological samples regardless of their transparency. The method is based on the precise measurement of optical path length difference of the end surfaces of objects, using a dual-arm axial-scanning low-coherence interferometer. This removes any consideration of the shape, thickness, or transparency of testing objects when performing the measurement. Scanning the reference simplifies the measurement setup, resulting in unambiguous measurement. Using a 1310 nm wavelength superluminescent diode, with a 65 nm bandwidth, the measurement accuracy was as high as 11.6 µm. We tested the method by measuring the thickness of both transparent samples and nontransparent soft biological tissues.
Assuntos
Interferometria/instrumentação , Óptica e Fotônica/instrumentação , Refratometria/instrumentação , Animais , Bovinos , Desenho de Equipamento , Interferometria/métodos , Refratometria/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , SoftwareRESUMO
Mortality and morbidity after cardiac arrest remain high due to ischemia/reperfusion (I/R) injury causing multi-organ damages, even after successful return of spontaneous circulation. We previously generated H2O2-activatable antioxidant nanoparticles formulated with copolyoxalate containing vanillyl alcohol (PVAX) to prevent I/R injury. In this study, we examined whether PVAX could effectively reduce organ damages in a rat model of whole-body ischemia/reperfusion injury (WBIR). To induce a cardiac arrest, 70µl/100 g body weight of 1 mmol/l potassium chloride was administered via the jugular venous catheter. The animals in both the vehicle and PVAX-treated groups had similar baseline blood pressure. After 5.5 minutes of cardiac arrest, animals were resuscitated via intravenous epinephrine followed by chest compressions. PVAX or vehicle was injected after the spontaneous recovery of blood pressure was noted, followed by the same dose of second injection 10 minutes later. After 24 hours, multiple organs were harvested for pathological, biochemical, molecular analyses. No significant difference on the restoration of spontaneous circulation was observed between vehicle and PVAX groups. Analysis of organs harvested 24 hours post procedure showed that whole body I/R significantly increased reactive oxygen species (ROS) generation, inflammatory markers, and apoptosis in multiple organs (heart, brain, and kidney). PVAX treatment effectively blocked ROS generation, reduced the elevation of pro-inflammatory cytokines, and decreased apoptosis in these organs. Taken together, our results suggest that PVAX has potent protective effect against WBIR induced multi-organ injury, possibly by blocking ROS-mediated cell damage.
Assuntos
Antioxidantes/farmacologia , Peróxido de Hidrogênio/farmacologia , Nanopartículas/química , Traumatismo por Reperfusão/prevenção & controle , Animais , Antioxidantes/administração & dosagem , Álcoois Benzílicos/química , Modelos Animais de Doenças , Feminino , Peróxido de Hidrogênio/administração & dosagem , Mediadores da Inflamação , Masculino , Insuficiência de Múltiplos Órgãos/prevenção & controle , Nanopartículas/administração & dosagem , Polímeros/química , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/antagonistas & inibidoresRESUMO
A single-arm interferometer based optical coherence tomography (OCT) system known as common-path OCT (CPOCT) is rapidly progressing towards practical application. Due in part to the simplicity and robustness of its design, Fourier Domain CPOCT (FD-CP-OCT) offers advantages in many endoscopic sensing and imaging applications. FD-CP-OCT uses simple, interchangeable fiber optic probes that are easily integrated into small and delicate surgical tools. The system is capable of providing not only high resolution imaging but also optical sensing. Here, we report progress towards practical application of FD-CP-OCT in the setting of delicate microsurgical procedures such as intraocular retinal surgery. To meet the challenges presented by the microsurgical requirements of these procedures, we have developed and initiated the validation of applicable fiber optic probes. By integrating these probes into our developing imaging system, we have obtained high resolution OCT images and have also completed a demonstration of their potential sensing capabilities. Specifically, we utilize multiple SLEDs to demonstrate sub 3-micron axial resolution in water; we propose a technique to quantitatively evaluate the spatial distribution of oxygen saturation levels in tissue; and we present evidence supportive of the technology's surface sensing and tool guidance potential by demonstrating topological and motion compensation capabilities.
RESUMO
SIGNIFICANCE: Nanomedicine is an application of nanotechnology that provides solutions to unmet medical challenges. The unique features of nanoparticles, such as their small size, modifiable components, and diverse functionality, make them attractive and suitable materials for novel diagnostic, therapeutic, or theranostic applications. Cardiovascular diseases (CVDs) are the major cause of noncommunicable illness in both developing and developed countries. Nanomedicine offers novel theranostic options for the treatment of CVDs. Recent Advances: Many innovative nanoparticles to target reactive oxygen species (ROS) have been developed. In this article, we review the characteristics of nanoparticles that are responsive to ROS, their limitations, and their potential clinical uses. Significant advances made in diagnosis of atherosclerosis and treatment of acute coronary syndrome using nanoparticles are discussed. CRITICAL ISSUES: Although there is a tremendous potential for the nanoparticle applications in medicine, their safety should be considered while using in humans. We discuss the challenges that may be encountered with some of the innovative nanoparticles used in CVDs. FUTURE DIRECTIONS: The unique properties of nanoparticles offer novel diagnostic tool and potential therapeutic strategies. However, nanomedicine is still in its infancy, and further in-depth studies are needed before wide clinical application is achieved.
Assuntos
Doenças Cardiovasculares/tratamento farmacológico , Nanopartículas/química , Nanotecnologia , Estresse Oxidativo/efeitos dos fármacos , Nanomedicina Teranóstica , Animais , HumanosRESUMO
The aim of this study is to design GoogLeNet deep neural network architecture by expanding the kernel size of the inception layer and combining the convolution layers to classify the electrocardiogram (ECG) beats into a normal sinus rhythm, premature ventricular contraction, atrial premature contraction, and right/left bundle branch block arrhythmia. Based on testing MIT-BIH arrhythmia benchmark databases, the scope of training/test ECG data was configured by covering at least three and seven R-peak features, and the proposed extended-GoogLeNet architecture can classify five distinct heartbeats; normal sinus rhythm (NSR), premature ventricular contraction (PVC), atrial premature contraction (APC), right bundle branch block (RBBB), and left bundle brunch block(LBBB), with an accuracy of 95.94%, an error rate of 4.06%, a maximum sensitivity of 96.9%, and a maximum positive predictive value of 95.7% for judging a normal or an abnormal beat with considering three ECG segments; an accuracy of 98.31%, a sensitivity of 88.75%, a specificity of 99.4%, and a positive predictive value of 94.4% for classifying APC from NSR, PVC, APC beats, whereas the error rate for misclassifying APC beat was relative low at 6.32%, compared with previous research efforts.
Assuntos
Aprendizado Profundo , Eletrocardiografia , Processamento de Sinais Assistido por Computador , Arritmias Cardíacas/diagnóstico , Bases de Dados Factuais , Eletrocardiografia/classificação , Eletrocardiografia/métodos , Humanos , Internet , Sensibilidade e EspecificidadeRESUMO
The aim of this study was to evaluate the anticancer activity of bioinspired silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) against mouse myoblast cancer cells (C2C12). Both AgNPs and AuNPs were biologically synthesized using Spinacia oleracea Linn., aqueous leaves extract. UV-Vis. spectrophotometer, high resolution-transmission electron microscopy (HR-TEM), field emission-scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) studies supported the successful synthesis of AgNPs and AuNPs. Both these NPs have shown cytotoxicity against C2C12 cells even at very low concentration (5µg/mL). Acridine orange/Ethidium bromide (AO/EB) dual staining confirmed the apoptotic morphological features. The levels of caspase enzymes (caspase-3 and caspase-7) were significantly up-regulated in NPs treated myoblast cells than the plant extract. Furthermore, in zebrafish embryo toxicity study, AgNPs showed 100% mortality at 3µg/mL concentration while AuNPs exhibited the same at much higher concentration (300mg/mL). Taken together, these results provide a preliminary guidance for the development of biomaterials based drugs to fight against the fatal diseases for example cancer.
Assuntos
Antineoplásicos/farmacologia , Embrião não Mamífero/efeitos dos fármacos , Ouro/farmacologia , Nanopartículas Metálicas/toxicidade , Mioblastos/patologia , Prata/farmacologia , Testes de Toxicidade , Peixe-Zebra/embriologia , Laranja de Acridina/metabolismo , Animais , Apoptose/efeitos dos fármacos , Caspases/metabolismo , Linhagem Celular Tumoral , Forma Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Embrião não Mamífero/anormalidades , Etídio/metabolismo , Nanopartículas Metálicas/ultraestrutura , Camundongos , Mioblastos/efeitos dos fármacos , Técnicas Fotoacústicas , Extratos Vegetais/farmacologia , Folhas de Planta/química , Spinacia oleracea/química , Coloração e Rotulagem , Difração de Raios XRESUMO
Impedances and joint angles were simultaneously measured during ankle and knee movements. The correlation coefficients of the joint angle and the impedance change from human leg movement were obtained using an electro-goniometer and a four-channel impedance measurement system. Because the impedance changes resulting from ankle and knee movements depended heavily on the electrode placement, we determined the optimum electrode configurations for those movements by searching for high correlation coefficients, large impedance changes and minimum interferences in ten subjects (age: 20+/-4). Our optimum electrode configurations showed strong relationships between the ankle joint angle and lower leg impedance (correlation coefficient=-0.91+/-0.06) and between the knee joint angle and knee impedance (correlation coefficient=0.94+/-0.04). The reproducibilities of the impedance changes of five subjects due to the ankle and knee were 6.3+/-1.9% and 5.1+/-1.7% for the optimum electrode pairs, respectively. We propose that this optimum electrode configuration would be useful for future studies involving the convenient measurement of leg movements by the impedance method.
Assuntos
Articulação do Tornozelo/fisiologia , Impedância Elétrica , Eletrodos , Articulação do Joelho/fisiologia , Movimento/fisiologia , Pletismografia de Impedância/métodos , Amplitude de Movimento Articular/fisiologia , Adulto , Humanos , Perna (Membro)/fisiologia , Masculino , Exame Físico/instrumentação , Exame Físico/métodos , Pletismografia de Impedância/instrumentação , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
Here we developed a real-time photoacoustic tomography (PAT) imaging acquisition device based on the linear array transducer utilized on ultrasonic devices. Also, we produced a phantom including diverse contrast media and acquired PAT imaging as the light source wavelength was changing to see if the contrast media reacted. Indocyanine green showed the highest reaction around the 800-nm band, methylene blue demonstrated the same in the 750-nm band, and gold nanoparticle showed the same in the 700-nm band. However, in the case of superparamagnetic iron oxide, we observed not reaction within the wavelength bands used herein to obtain imaging. Moreover, we applied selective filtering to the acquired PAT imaging to remove noise from around and reinforce the object's area. Consequentially, we could see the object area in the imaging was effectively detected and the image noise was removed.
Assuntos
Técnicas de Imagem por Elasticidade/instrumentação , Aumento da Imagem/instrumentação , Técnicas Fotoacústicas/instrumentação , Processamento de Sinais Assistido por Computador/instrumentação , Transdutores , Sistemas Computacionais , Técnicas de Imagem por Elasticidade/métodos , Desenho de Equipamento , Análise de Falha de Equipamento , Aumento da Imagem/métodos , Imagens de Fantasmas , Técnicas Fotoacústicas/métodos , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
Reactive oxygen species (ROS) are generated from the endogenous oxidative metabolism or from exogenous pro-oxidant exposure. Oxidative stress occurs when there is excessive production of ROS, outweighing the antioxidant defense mechanisms which may lead to disease states. Hydrogen peroxide (H2O2) is one of the most abundant and stable forms of ROS, implicated in inflammation, cellular dysfunction and apoptosis, which ultimately lead to tissue and organ damage. This review is an overview of the role of ROS in different diseases. We will also examine ROS-activated nanomaterials with emphasis on hydrogen peroxide, and their potential medical implications. Further development of the biocompatible, stimuli-activated agent responding to disease causing oxidative stress, may lead to a promising clinical use.
Assuntos
Antioxidantes/química , Nanoestruturas/química , Espécies Reativas de Oxigênio/química , Nanomedicina Teranóstica/métodos , Animais , Apoptose , Boro/química , Ésteres/química , Humanos , Peróxido de Hidrogênio/química , Oxalatos/química , Estresse Oxidativo , Polipropilenos/química , Prolina/química , Espécies Reativas de Nitrogênio/química , Selênio/química , Transdução de Sinais , Silício/química , Sulfetos/química , Superóxidos/químicaRESUMO
A real-time photoacoustic tomography (PAT) system is developed using a linear array probe and phantom images are acquired with a pattern of line structure. Moreover, it is attempted to detect line structures from the acquired images by Hough transform. This effort leads to the measurement of a process of magenta passing through a tube and acquisition of images at a speed of about 2 frame/sec. Besides, it is confirmed that the Hough transform applied on the acquired PAT images has the detection rate of about 50% for delineating a line structure.
Assuntos
Algoritmos , Técnicas de Imagem por Elasticidade/instrumentação , Técnicas de Imagem por Elasticidade/métodos , Técnicas Fotoacústicas/instrumentação , Técnicas Fotoacústicas/métodos , Transdutores , Sistemas Computacionais , Desenho de Equipamento , Análise de Falha de Equipamento , Aumento da Imagem/instrumentação , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/instrumentação , Interpretação de Imagem Assistida por Computador/métodos , Imagens de Fantasmas , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
The very first step to process electrocardiogram (ECG) signal is to eliminate baseline wandering interference that is usually caused by electrode-skin impedance mismatch, motion artifacts due to a patient's body moment or respiratory breathing. A new method is thus suggested to remove baseline wandering in ECG by improving the detrending method that was originally proposed for eliminating slow non-stationary trends from heart rate variability (HRV). In our proposed method, a global trend is estimated in terms of baseline wandering by merging the local trend based on an ECG segment that represents a part of the ECG signal. The experimental results show that the improved detrending method can efficiently resolve baseline wandering without distorting any morphological characteristic embedded in the ECG signal in no time delay manner.
Assuntos
Artefatos , Diagnóstico por Computador/métodos , Eletrocardiografia/métodos , Frequência Cardíaca/fisiologia , Reconhecimento Automatizado de Padrão/métodos , Processamento de Sinais Assistido por Computador , Algoritmos , Humanos , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
A new rehabilitation training system was developed to improve postural balance control by combining virtual reality technology with an unfixed bicycle. Twenty healthy subjects participated in the present study by riding the virtual cycling system under two different conditions: with or without visual feedback. Data were collected on the following parameters: path deviation, cycling velocity, etc. As a result of conducting the repeated training, results showed improvement not only in the ability to control balance and weight shift but also in the overall cycling ability including the degree of path deviation and the cycling speed. It was concluded that the system was effective as a training device and, in addition, the technology might have a wider applicability to the rehabilitation field.
Assuntos
Ciclismo/fisiologia , Terapia por Exercício/métodos , Movimento/fisiologia , Equilíbrio Postural/fisiologia , Postura/fisiologia , Terapia Assistida por Computador/métodos , Interface Usuário-Computador , Adulto , Animais , Meio Ambiente , Técnicas de Exercício e de Movimento/instrumentação , Técnicas de Exercício e de Movimento/métodos , Terapia por Exercício/instrumentação , Retroalimentação/fisiologia , Humanos , Pessoa de Meia-Idade , Transtornos dos Movimentos/reabilitação , Transtornos de Sensação/reabilitação , Análise e Desempenho de Tarefas , Terapia Assistida por Computador/instrumentação , Visão Ocular/fisiologiaRESUMO
Conventional urodynamics systems have been widely used for the assessment of bladder functions. However, they have some drawbacks due to the unfamiliar circumstances for the patient, restrictive position during the test, expense and immovability of the instrument as well as the unphysiological filling of the bladder. To mitigate these problems, we developed a fully ambulatory urodynamics monitoring system, which enables the abdominal pressure to be measured in a non-invasive manner, as well as the manual recording of various events such as the bladder sensations or leakage of urine. Conventional (CMG) and furosemide-stimulated filling cystometry (FCMG) were performed for 28 patients with neurogenic bladders caused by spinal cord injury (24 males and 4 females, age: 49.4 ± 13.9 years, BMI: 23.5 ± 2.4). There were high correlation coefficients (r=0.97 ± 0.02) between the clinical parameters measured by the conventional rectal catheter and those measured by our non-invasive algorithm in the FCMG studies. Also, 10 of the patients (36%) were diagnosed as having different reflexibility of the bladder between conventional CMG and FCMG (p<0.05). In the patients with detrusor overactivity, the average volume and detrusor pressure at bladder sensation in FCMG were lower than those in CMG, while the average compliance was higher (p<0.05). In the patients with areflexic bladders, the number of patients with detrusor overactivity was higher in FCMG and leakage was observed more frequently. These results showed that our system could be a useful additional tool in the clinical assessment of patients in which conventional cystometry failed to explain their symptoms.
Assuntos
Assistência Ambulatorial , Monitorização Fisiológica/instrumentação , Traumatismos da Medula Espinal , Urodinâmica/fisiologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , SoftwareRESUMO
Knee sound signals generated by knee movement are sometimes associated with degeneration of the knee joint surface and such sounds may be a useful index for early disease. In this study, we detected the acoustical parameters, such as the fundamental frequency (F0), mean amplitude of the pitches, and jitter and shimmer of knee sounds, and compared them according to the pathological conditions. Six normal subjects (4 males and 2 females, age: 28.3 ± 2.3 years) and 11 patients with knee problems were enrolled. The patients were divided into the 1st patient group (5 males and 1 female, age: 30.2 ± 10.3 years) with ruptured wounds of the meniscus and 2nd patient group (2 males and 3 females, age: 42.1 ± 16.2 years) with osteoarthritis. The mean values of F0, jitter and shimmer of the 2nd patient group were larger than those of the normal group, whereas those of the 1st patient group were smaller (p < 0.05). Also, the F0 and jitter in the standing position were larger than those in the sitting position in both the 1st and 2nd patient groups (p < 0.05). These results showed good potential for the non-invasive diagnosis and early detection of articular pathologies via an auscultation.
Assuntos
Auscultação/métodos , Articulação do Joelho/patologia , Programas de Rastreamento/métodos , Osteoartrite do Joelho/diagnóstico , Adulto , Cartilagem/fisiopatologia , Diagnóstico Precoce , Feminino , Humanos , Artropatias/diagnóstico , Masculino , Pessoa de Meia-Idade , Amplitude de Movimento ArticularRESUMO
This paper describes a 3D endoscopic video system designed to improve visualization and enhance the ability of the surgeon to perform delicate endoscopic surgery. In a comparison of the polarized and conventional electric shutter-type stereo imaging systems, the former was found to be superior in terms of both accuracy and speed for suturing and for the loop pass test. Among the groups performing loop passing and suturing, there was no significant difference in the task performance between the 2D and 3D modes, however, suturing was performed 15% (p < 0.05) faster in 3D mode by both groups. The results of our experiments show that the proposed 3D endoscopic system has a sufficiently wide viewing angle and zone for multi-viewing.
Assuntos
Endoscopia/instrumentação , Endoscopia/métodos , Aumento da Imagem/instrumentação , Aumento da Imagem/métodos , Imageamento Tridimensional/instrumentação , Imageamento Tridimensional/métodos , Desenho de Equipamento , Humanos , Interpretação de Imagem Assistida por Computador , Análise e Desempenho de Tarefas , Gravação em VídeoRESUMO
In this paper, we describe a polarization sensitive (PS) subcutaneous and muscular imaging system based on common path optical coherence tomography (CP-OCT) using a near infrared source. The axial and lateral resolutions of the PS-OCT system are 9 and 6 µm, respectively. The main goal of this work is to build a high-resolution and minimally invasive optical imager for examining various kinds of cutaneous substructures with intrinsic or form birefringence. The internal structural information is extracted by the real-time signal analysis (Fourier Transform) of the modulated spectral intensity depending on the beam and tissue birefringence. The preliminary results using fresh beef longissimus muscle and in vivo Rattus norvegicus (rat) show that it is possible to visualize the birefringence effect of the tissue collagen fibers in the samples in order to achieve superior image contrast and sensitivity for the detection of hidden dermal structures. Compared to conventional CP-OCT, the proposed PS-OCT system provides depth-resolved images, which reflect the tissue birefringence.
Assuntos
Tecido Adiposo/fisiologia , Músculo Esquelético/fisiopatologia , Tomografia de Coerência Óptica , Algoritmos , Animais , Birrefringência , Bovinos , Raios Infravermelhos , Ratos , Tomografia de Coerência Óptica/instrumentaçãoRESUMO
The clinical scales used for the evaluation of the spasticity have some drawbacks, in spite of their simplicity and ease of assessment, and their inter- and intra-rater reliability remains controversial. The aim of this study is to develop a portable system for the objective and reliable evaluation of the spasticity based on the K-means clustering of the tonic stretch reflex threshold (TSRT) and to compare the discrimination performance of the level of spasticity determined by our method with that by the conventional modified Ashworth scale (MAS). Fifteen hemiplegic patients (7 males and 8 females, age: 63.5±15.6) participated in the study. The average and standard deviation values of the TSRTs were 127.9±1.6, 121.8±1.5 and 117.9±1.3 in groups G1, G2 and G3, respectively, and there were significant differences between the TSRTs of each group (p<0.05). Also, our groups classified by the criteria of the TSRT had a strong negative correlation (r=-0.95, r(2)=0.90, p<0.05) between the level of spasticity and TSRTs. These results demonstrated that our system could be clinically more useful for the quantitative and reliable discrimination of the spasticity than the conventional MAS.