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1.
Background
Stem cell therapy has a huge potential to enhance the recovery of damaged tissues and organs. However, it has been reported that majority of implanted stem cells cannot survive after implantation. Therefore, noninvasive monitoring of stem cell viability is essential to estimate the efficacy of stem cell therapy. However, current imaging methods have disadvantages for monitoring of stem cell viability such as cost, penetration depth, and safety. To overcome the limitations, photoacoustic imaging well known for sufficient penetration depth, relatively low cost, and non-ionizing radiation can be a novel alternative assessment method of stem cell viability.Methods
In this study, indocyanine green was used as exogenous photoacoustic contrast agents to label mesenchymal stem cells. The photoacoustic signals were acquired before and after the cell death and quantified to monitor photoacoustic signal changes related to the cell viability.Results
The fluorescence intensity changes of ICG labeled MSCs corresponded to decrease of PA intensity after cell death. Furthermore, the PA imaging of MSCs showed similarity between the PA intensity and the cell viability.Conclusion
The experimental results imply the feasibility of noninvasive detection of stem cell viability during therapeutic procedures. 相似文献2.
Greta Jarockyte Dominyka Dapkute Vitalijus Karabanovas Justinas V. Daugmaudis Feliksas Ivanauskas Ricardas Rotomskis 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(4):914-923
Background
Monolayer cell cultures have been considered the most suitable technique for in vivo cellular experiments. However, a lot of cellular functions and responses that are present in natural tissues are lost in two-dimensional cell cultures. In this context, nanoparticle accumulation data presented in literature are often not accurate enough to predict behavior of nanoparticles in vivo. Cellular spheroids show a higher degree of morphological and functional similarity to the tissues.Methods
Accumulation and distribution of carboxylated CdSe/ZnS quantum dots (QDs), chosen as model nanoparticles, was investigated in cellular spheroids composed of different phenotype mammalian cells. The findings were compared with the results obtained in in vivo experiments with human tumor xenografts in immunodeficient mice. The diffusive transport model was used for theoretical nanoparticles distribution estimation.Results
QDs were accumulated only in cells, which were localized in the periphery of cellular spheroids. CdSe/ZnS QDs were shown to be stable and inert; they did not have any side-effects for cellular spheroids formation. Penetration of QDs in both cellular spheroids and in vivo tumor model was limited. The mathematical model confirmed the experimental results: nanoparticles penetrated only 25 μm into cellular spheroids after 24 h of incubation.Conclusions
Penetration of negatively charged nanoparticles is limited not only in tumor tissue, but also in cellular spheroids.General Significance
The results presented in this paper show the superior applicability of cellular spheroids to cell monolayers in the studies of the antitumor effect and penetration of nanomedicines. 相似文献3.
Background
Convenient and precise measurement of the Cobb angle using a small size X-ray detector has been required for local clinics.Methods
Cobb angle measurement system using a conventional X-ray source and detector is proposed for accurate Cobb angle measurement. The system consists of a conventional X-ray source, a ruler-added X-ray table, a conventional X-ray detector, and an image processing program. The X-ray table has the lead ruler patterns. The patterns remain white ruler patterns on X-ray images. The proposed image processing program merges the three spinal X-ray images into one whole spinal X-ray image by detecting the ruler patterns on the three spinal X-ray images.Results
In order to evaluate our program, Cobb angle measured in the merged image is compared with Cobb angle measured in the X-ray image taken by a large X-ray detector. Average of difference between them is 2.251 degree and standard deviation is 1.339.Conclusion
The developed measurement system demonstrated its measurement performance accurately and practically. 相似文献4.
Background
Many human tissues are comprised of multilayered tissue structures in which spatial organization is essential to provide biological tissue functions.Methods
Recently, strategies such as 3D bioprinting, photolithography, 3D auto-assembly, molding or bulk acoustic cells manipulation have been developed to fabricate layered tissue mimics. These methods have broad applications in tissue engineering for the bioengineering of multilayered structures, and for the fundamental understanding of many microphysiological and pathological process like cell differentiation. Each method relies on the use of a special scaffold structure made of natural or artificially created biopolymers, and of specific cell types.In the field of neuronal 3D constructs fabrication, where ex-vivo samples are difficult to get, different strategies have been developed going from rat neurons culture to embryonic stem cells culture and differentiation into neurons after their encapsulation in 3D scaffolds.Conclusion
All those possibilities open new perspectives for the future, aiming to the development of different types of tissues composed of different multilayer structures. 相似文献5.
Background
In developed countries, 10% of labors occur prematurely and are mainly due to contractions appearing too soon during the pregnancy. To detect such contractions, we developed a wearable device able to record both the electrical activity of the uterus, electrohysterograms (EHG), thanks to 18 electrodes, but also the mother movements, thanks to an embedded accelerometer.Methods
In this study, we investigated the detectability of a begin/end of contraction by analyzing EHG signals with the Bayes Information Criterion, and we analyzed the three axis accelerometer signals to characterize the mother activity when she is carrying the device (such movements being possible sources of artifacts in the EHG signals).Results
For the contraction detections, we obtained 68.38% (599/876) of good detection but a too high number of false alarms (1073). To reduce this false alarm number, we analyzed the three accelerometer signals and detected 98.7% of static phases of the mother and 95% of dynamic ones.Discussion
The detection of precise movements inside the dynamic cluster still has to be investigated to improve the first obtained results, as well as the combination of these two research ways (EHG and accelerometer) applied at the same time during recording. 相似文献6.
Background
The electrocardiogram (ECG) signals provide important information about the heart electrical activities in medical and diagnostic applications. This signal may be contaminated by different types of noises. One of the noise types which has a considerable overlap with the ECG signals in frequency domain is electromyogram (EMG). Among the exciting approaches for de-noising the ECG signals, those based on singular spectrum analysis (SSA) are popular.Methods
In this paper, we propose a method based on SSA to separate the ECG signals from EMG noises. In general, SSA contains four steps as: embedding, singular value decomposition, grouping, and diagonal averaging. Among these steps, grouping step contains parameter (indices) which can be adjusted to achieve the desirable results. Indeed, grouping is one of the important steps of SSA as the ECG and EMG signals are separated in this step. Hence, in the proposed method, a new criterion is presented to select the indices in grouping step to separate the ECG from EMG signal with higher accuracy.Results
Performance of the proposed method is investigated using several experiments. Two sub-sets from Physionet MIT-BIH arrhythmia database are used for this purpose.Conclusion
The experimental results demonstrate effectiveness of the proposed method in comparison with other SSA-based techniques. 相似文献7.
H. Tannous D. Istrate A. Benlarbi-Delai J. Sarrazin M.-C. Ho Ba Tho T.T. Dao 《IRBM》2018,39(6):440-444
Background
Serious games have recently immerged as a good tool for physical rehabilitation. This new technology can be used at home, to complement a traditional, clinic based, rehabilitation program. To implement a serious game at home, we need to use multiple sensors to record patients' data. Many serious games use visual motion capture techniques, like the Kinect camera, due to their low price and high portability. On the other hand, some other systems use inertial sensors to collect data at a higher degree of accuracy. In previous works, we showed that a serious gaming system could benefit from combining data from different sensors. However, the use of inertial sensors, in a home-based setting, remains a challenge since they need to be supplied by an independent battery source, which could influence the acceptability of such systems.Methods
In this paper, we present an energy consumption study, performed on the inertial sensors used in our serious game system.Results
The results show that the sensors are rarely affected by environmental factors. They also show that the sensors can function continuously for about 14 hours without battery recharge.Conclusion
Finally, these results allowed us to establish an optimal set up configuration for home based rehabilitation using serious games. 相似文献8.
Background
Routine ergonomic assessment of postures and gestures in the workplace are mostly conducted by visual observations, either direct or based on video recordings. Nowadays, low-cost three-dimensional cameras like Microsoft Kinect offers the possibility of recording the full kinematics of workers in a non-intrusive way, providing a more precise, and reliable assessment of their motor strategies.Methods
We have developed a tracking application using the Kinect SDK for Windows in C?, allowing the simultaneous recording of the three-dimensional coordinates of all the body points tracked by the Microsoft Kinect at a sampling frequency of 30 Hz and an expected accuracy of 3 cm. Measurements are performed on violinists, whose playing is representative of a work situation involving repeated gestures and postures that can be described as non-ergonomic.Results
Microsoft Kinect can be efficiently used to quantify the motion performed by the violinists. Playing strategies can even be noticed despite the low-cost nature of the sensor used.Conclusion
Low-cost three-dimensional cameras can be a useful aid in ergonomic risk assessment of developing musculoskeletal disorders and give the example of the repetition of movements and postural items included in the OCRA checklist, whose scoring can be facilitated by such a device. 相似文献9.
Background
Label fusion is a core step of Multi-Atlas Segmentation (MAS), which has a decisive effect on segmentation results. Although existed strategies using image intensity or image shape to fuse labels have got acceptable results, there is still necessity for further performance improvement. Here, we propose a new label fusion strategy, which considers the joint information of intensity and registration quality.Methods
The correlation between any two atlases is taken into account and the probability that two atlases both give wrong label is used to compute the fusion weights. The probability is jointly determined by the registration error and intensity similarity of the two corresponding atlas-target image pairs. The proposed label fusion algorithm is named Registration Error and Intensity Similarity based Label Fusion (REIS-LF).Results
Using 3D Magnetic Resonance (MR) images, the proposed REIS-LF algorithm is validated in brain structure segmentation including the hippocampus, the thalamus and the nuclei of the basal ganglia. The REIS-LF algorithm has higher segmentation accuracy and robustness than the baseline AQUIRC-W algorithm.Conclusions
Taking the registration quality, the inter-atlas correlations and intensity differences into account in label fusion benefits to improve the object segmentation accuracy and robustness. 相似文献10.
A. Jabeen B. Reeder D. Svistunenko S. Hisaindee S. Ashraf S. Al-Zuhair S. Battah 《IRBM》2019,40(1):51-61
Background
In recent years, microalgae (MA) have attracted much interest considering their possible therapeutic application. They contain active natural compounds or derivatives (extracts, pure or chemically modified compounds) that have increasing applications in the pharmaceutical industry.Methods
The present study aims to examine microalgae for new photosensitizers, with a potential to be used in the light-associated treatment of tumors. Semi-purified extracts of several microalgae strains were evaluated as photosensitizers for photodynamic therapy (PDT) applications. Four tumor cell lines (A549, LNCap, MCF-7, and MDA-MB 435) were used to assess 34 samples extracted by three methods: cellulase enzyme, lysozyme enzyme and ultra-sonication. The fluorescence measurements and the recorded images alongside the spectral intensities between 650–800 nm wavelengths provided characteristic features to some of the contents of the examined extracts.Results
Several microalgae constituents activated by blue light (BL), red light (RL) or both (in sequence) exhibited significant effects on the viability of the tumor cell lines, decreasing it as much as 95% for certain MA constituents. Majority of the MA constituents showed a higher phototoxicity after exposure to both blue and red lights than the photo-induced toxicity when exposed to a single light source. The viability of the tumor cells exhibited the dose dependent response with the MA constituents.Conclusion
The results clearly showed that MA constituents are potential photosensitizers that have a significant photo-damage effects on the tested cancer cells. 相似文献11.
Background
Aiming for autonomous living for the people after a stroke is the challenge these days especially for swallowing disorders or dysphagia. The most common cause of dysphagia is stroke. In France, stroke occurs every 4 minutes, which implies 13000 hospitalizations per year. Currently, continuous medical home monitoring of patients is not available. The patient must be hospitalized or visit the medical community for possible follow-up. It is in this context that E-SwallHome (Swallowing & Breathing: Modelling and e-Health at Home) project proposes to develop tools, from hospital care until the patient returns home, which are able to monitor in real time the process of swallowing.Method
This paper presents a relevant health problem affecting patient recovering from stroke. We propose a frequency acoustical analysis for automatic detection of swallowing process and a non-invasive acoustic based method to differentiate between swallowing sounds and other sounds in normal ambient environment during food intake.Result
The proposal algorithm for events detection gives a global rate of good detection of 87.31%. Classification of sounds of swallowing and other sounds based on Gaussian Mixture Models (GMM), using the leave-one-out approach according to the small amount of data in our database, gives a good recognition rate of swallowing sounds of 84.57%.Conclusion
The proposal method has great potential to assist in the clinical evaluation using only swallowing sounds, which is a non-invasive technic for swallowing studies. 相似文献12.
13.
Background
The contrast enhancement of Magnetic Resonance Imaging (MRI) data is quite challenging as the noise present in this data also get amplified in this process. Dynamic Stochastic Resonance (DSR) is the technique that utilizes the noise to enhance the contrast of MRI data.Method
The present study proposes the cascaded stochastic resonance, which exploits the properties of modified potential neuron model and quartic bistable model of DSR. The Multi-objective Particle Swarm Optimization (MOPSO) tunes the DSR parameters associated with the cascading of both the models. The MOPSO produces a set of the solution called Pareto front for the maximization of two image quality measures, i.e., contrast enhancement factor and universal image quality index. Further, the maximization of another image quality measure, i.e., anisotropy helps to obtain the optimum enhanced image from the Pareto fronts solution.Results
The present study included the simulated and real MRI data. The results show that the proposed method obtained mean contrast enhancement factor, universal image quality index and anisotropy equal to 1.79, 0.78 and 0.021 respectively. These values are better than those obtained for classical bistable DSR and other conventional contrast enhancement techniques. The proposed algorithm has been tested on real MRI data as well and found valuable in the diagnosis of lacunar infarct and mesial temporal sclerosis.Conclusion
The cascaded DSR based on MOPSO has shown promising results and may be highly beneficial to the diagnosis of different brain pathology. 相似文献14.
Background
Fatty Liver Disease (FLD) is one of the most critical diseases that should be detected and cured at the earlier stage in order to decrease the mortality rate. To identify the FLD, ultrasound images have been widely used by the radiologists. However, due to poor quality of ultrasound images, they found difficulties in recognizing FLD. To resolve this problem, many researchers have developed various Computer Aided Diagnosis (CAD) systems for the classification of fatty and normal liver ultrasound images. However, the performance of existing CAD systems is not good in terms of sensitivity while classifying the FLD.Methods
In this paper, an attempt has been made to present a CAD system for the classification of liver ultrasound images. For this purpose, texture features are extracted by using seven different texture models to represent the texture of Region of Interest (ROI). Highly discriminating features are selected by using Mutual Information (MI) feature selection method.Results
Extensive experiments have been carried out with four different classifiers, and for carrying out this study, 90 liver ultrasound images have been taken. From the experimental results, it has been found that the proposed CAD system is able to give 95.55% accuracy and sensitivity of 97.77% with the 20 best features selected by the MI feature selection technique.Conclusion
The experimental results show that the proposed system can be used for the classification of fatty and normal liver ultrasound images with higher accuracy. 相似文献15.
Background
Polycaprolactone (PCL) is a biodegradable polymer which is used in tissue engineering applications thanks to its many favorable characteristics. However, PCL surfaces are known as hydrophobic leading to a lack of favorable cell response. To overcome this problem, PCL surfaces will undergo a surface functionalization by grafting bioactive polymers bearing ionic groups.Objective
Our laboratory has demonstrated that the grafting of bioactive polymers onto biomaterials can improve cell and antibacterial response. The objective of this work is to functionalize PCL surfaces by the grafting of a bioactive polymer.Methods
The grafting of an ionic polymer poly(sodium styrene sulfonate) (polyNaSS), using UV irradiation on PCL surfaces was carried out in a two-steps reaction process. PCL surfaces were (1) chemically oxidized in order to allow the formation of (hydro)peroxide species. (2) Then immersed in a sodium styrene sulfonate (NaSS) solution and placed under UV irradiation to induce the decomposition of (hydro)peroxides to form radicals able to initiate the polymerization of the NaSS monomer. Various parameters, such as polymerization time, the effect of the surface activation, lamp power and monomer concentration were investigated in order to optimize the yield of polyNaSS grafting. The amount of polyNaSS grafted onto PCL surfaces was first determined by toluidine blue colorimetric method and characterized by contact angle measurement, Fourier-transform infrared spectra recorded in attenuated total reflection mode (ATR-FTIR), scanning electron microscopy with Oxford energy dispersive spectroscopy (SEM-EDS).Results
Various techniques showed that the grafting of ionic polymer polyNaSS bearing sulfonate groups was successful by using radicals from (hydro)peroxides able to initiate the radical polymerization of ionic monomers onto PCL surfaces.Conclusion
We developed a new approach of radical grafting which allows us to successfully graft bioactive polymer polyNaSS covalently to PCL surfaces using UV irradiation. 相似文献16.
Aminul Islam Khan Qian Lu Dan Du Yuehe Lin Prashanta Dutta 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(12):2779-2787
Background
Polymeric nanoparticles (PNP) have received significant amount of interests for targeted drug delivery across the blood-brain barrier (BBB). Experimental studies have revealed that PNP can transport drug molecules from microvascular blood vessels to brain parenchyma in an efficient and non-invasive way. Despite that, very little attention has been paid to theoretically quantify the transport of such nanoparticles across BBB.Methods
In this study, for the first time, we developed a mathematical model for PNP transport through BBB endothelial cells. The mathematical model is developed based on mass-action laws, where kinetic rate parameters are determined by an artificial neural network (ANN) model using experimental data from in-vitro BBB experiments.Results
The presented ANN model provides a much simpler way to solve the parameter estimation problem by avoiding integration scheme for ordinary differential equations associated with the mass-action laws. Furthermore, this method can efficiently deal with both small and large data set and can approximate highly nonlinear functions. Our results show that the mass-action model, constructed with ANN based rate parameters, can successfully predict the characteristics of the polymeric nanoparticle transport across the BBB.Conclusions
Our model results indicate that exocytosis of nanoparticles is seven fold slower to endocytosis suggesting that future studies should focus on enhancing the exocytosis process.General significance
This mathematical study will assist in designing new drug carriers to overcome the drug delivery problems in brain. Furthermore, we anticipate that this model will form the basis of future comprehensive models for drug transport across BBB. 相似文献17.
Wei Wang Peng Lin Haiying Yao Xi Jia Jirui Sun Lin Feng 《Saudi Journal of Biological Sciences》2018,25(5):982-985
Objective
This study identified the biological role of miR-4728 in Burkitt lymphoma (BL) process.Methods
Ramos cells were used to analyze MicroRNA-4728 (miR-4728) biological functions. MiR-4728 expression was investigated in 14 randomly chosen tumor tissues and 12 noncancerous tissues by qRT-PCR. Cyquant assay was used to monitor cell proliferation. Colony formation assay was performed to study the effectiveness of miR-4728 on the proliferation of cells. The effects of miR-4728 on MAPK signaling pathway were detected by luciferase reporter assay. The significance of differences between groups were evaluated by SPSS.Results
In this study, MiRNA-4728 was observed to down-regulated in BL tissues compared to the noncancerous tissues. Additionally, miR-4728 inhibited Ramos cell proliferation. Moreover, miR-4728 overexpression also decreased the MAPK signaling activity.Conclusion
Our results suggested that miR-4728 serves as a suppressor and antagonist of oncogenic MAPK in Burkitt lymphoma. The appropriate regulation of miR-4728 might be vital to improve BL treatment. 相似文献18.
Objective
Recently, Electroencephalogram (EEG) shows potential in the diagnosis of Alzheimer's disease and other dementia. We aim to investigate whether EEG and selected cognitive biomarkers can classify mild cognitive impairment (MCI), dementia and healthy subjects using support vector machine classifier in Indian cohort.Methods
Eight EEG biomarkers, power spectral density, skewness, kurtosis, spectral skewness, spectral kurtosis, spectral crest factor, spectral entropy (SE), fractal dimension (FD) were analyzed from 44 subjects in four conditions; eye-open, eye-close, finger tapping test (FTT) and continuous performance test (CPT). FFT and CPT are used to measure motor speed and sustained attention as these cognitive biomarkers are free from the educational barrier.Results
We achieved very good accuracy for each event from 73.4% to 89.8% for three binary classes. We investigated that FTT (84% accuracy), CPT (88% accuracy) were the most efficient events to diagnose MCI from dementia. MCI from control successfully diagnosed with 89.8% accuracy in FTT, 73.4% accuracy in CPT and 84.1% accuracy in eye open resting state. Even though cognitive biomarkers were also adequately diagnosed MCI from other groups.Conclusions
Our classifier findings are consistent with the utmost evidence. Yet, our results are promising and especially newfangled in the case of FTT and CPT from the prior studies. We developed an experimental protocol and proposed a novel technique to classify MCI with efficient biomarkers. 相似文献19.
Context
Microwave sensing appears to be an open wide field to investigate medical applications, such as monitoring of vital signs (temperature, arterial pressure, …), following different kinds of pathologies (cancer, glucose level …) and aid for medical diagnosis. It offers an alternative to determine the dielectric properties of biological tissues through the development of local non-invasive and/or embedded sensors, giving thus a kind of imaging by the dielectric contrast. Moreover, RF communications links between several sensors can be developed to realize “Body Area Networks”.Methods
Biological tissues having high dielectric permittivity and losses in the microwave frequency domain (around 1 GHz), a resonant dielectric characterization method is used to obtain a good sensitivity. The experimental setup is based on the measured changes of electrical characteristics of the resonator (resonance frequency and its shift and broadening) when a biological tissue is applied on it. In our case, the sensor is a microstrip ring resonator operating in a two-port configuration at a fundamental frequency of 1 GHz. It consists of a meander loop in order to reduce its dimensions. Besides, an original excitation is proposed leading to small perturbation of the resonator when high dielectric losses material is characterized. This increased greatly the sensitivity of the method to obtain the dielectric properties of the samples. Dielectric parameters are determined by fitting S parameters measurements results with those of simulations using electromagnetic software's (HFSS, CST).Results
Several biological tissues of animal origin were measured ex-vivo in the frequency range 0.5–5 GHz. The dielectric parameters obtained by this method are consistent with values proposed in databases or obtained by other researchers. A very good agreement between simulations and measurements is obtained leading to a good extraction of permittivity and losses of the tissues.Conclusions
This paper presents an improved microwave sensor, either for reduced dimensions as for sensitivity, able to perform dielectric characterization of material having high complex permittivity such as biological tissues. Experiments and electromagnetic simulations have been achieved on several animal tissues (chicken, beef, pork …), and results are in good agreement with literature. Works are in progress to optimize this sensor as an applicator for medical applications. 相似文献20.
K. Langlois H. Pillet F. Lavaste G. Rochcongar P. Rouch P. Thoreux W. Skalli 《IRBM》2018,39(4):251-260