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1.
C.R. Bawiec W.A. N&#x;Djin G. Bouchoux N. Sénégond N. Guillen J.-Y. Chapelon 《IRBM》2018,39(5):295-306
Background
Treatment of prostate cancer using endocavitary High Intensity Focused Ultrasound (HIFU) has become more commonplace since the first treatments in the 1990s. The gold standard HIFU strategy to treat prostate cancer is the complete thermal ablation of the entire prostate gland under real-time ultrasound (US) image guidance. A more desirable treatment and the current trend, however, is towards a focal treatment but more accurate and finely tunable thermal lesions are needed along with improved US imaging guidance. In this study, Capacitive Micromachined Ultrasound Transducer (CMUT) technology is being investigated, as they have shown recent promise for US imaging and potential to be used for HIFU therapy. They offer potential advantages over current piezoelectric designs in the context of ultrasound-guided HIFU (USgHIFU) focal therapies.Objective
The presented study evaluates the ability of a planar annular array CMUT design to achieve HIFU dynamic focusing and feasibility of generating thermal lesions in biological tissues.Method
The proposed CMUT design consists of a 64-element annular array for HIFU delivery with a space in the center that accommodates a high-resolution 256-element linear imaging array. The pressure field simulations of the HIFU portion of the array were performed using the Rayleigh integral method. The bioheat transfer equation was then used to predict lesion formation. The HIFU performances of the proposed CMUT phased-array design were compared to those of the device currently used in the clinic. Partial CMUT prototypes, including the therapeutic part only, were fabricated and experimentally characterized (electromechanical CMUT behavior, ultrasound pressure field distribution and acoustic intensity).Results
The planar 64-element annular CMUT design is capable of dynamically focusing a 3 MHz ultrasound beam at distances ranging from 32 to 72 mm, comparable in size and shape to the ones obtained with the clinical device. The simulated ultrasound fields correlated well to experimental measurements. Visual observation and impedance measurements of the CMUT cells allowed direct estimation of the collapse and snapback voltages of the ring-elements. The surface acoustic intensity of the CMUT ring-elements with both AC driving and DC bias voltages can achieve over 6 W/cm2, shown in simulation to be compatible with the generation of thermal lesions. The electro-acoustic efficiency of the CMUT elements increased with increasing DC bias voltages to reach 31%, and remained stable with increasing AC driving voltages. The ultrasound energy could be dynamically focused from this planar CMUT array during several dozen of minutes.Conclusion
This work demonstrates the feasibility of utilizing a planar CMUT probe for generating dynamic HIFU focusing and lesioning compatible with the ablation of prostate tissues under endocavitary treatment approach. Future investigations will consist of validating the lesioning capability experimentally both in vitro and in vivo. 相似文献2.
Caroline Vindry Théophile Ohlmann Laurent Chavatte 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(11):2480-2492
Background
Interest in selenium research has considerably grown over the last decades owing to the association of selenium deficiencies with an increased risk of several human diseases, including cancers, cardiovascular disorders and infectious diseases. The discovery of a genetically encoded 21st amino acid, selenocysteine, is a fascinating breakthrough in molecular biology as it is the first addition to the genetic code deciphered in the 1960s. Selenocysteine is a structural and functional analog of cysteine, where selenium replaces sulfur, and its presence is critical for the catalytic activity of selenoproteins.Scope of review
The insertion of selenocysteine is a non-canonical translational event, based on the recoding of a UGA codon in selenoprotein mRNAs, normally used as a stop codon in other cellular mRNAs. Two RNA molecules and associated partners are crucial components of the selenocysteine insertion machinery, the Sec-tRNA[Ser]Sec devoted to UGA codon recognition and the SECIS elements located in the 3′UTR of selenoprotein mRNAs.Major conclusions
The translational UGA recoding event is a limiting stage of selenoprotein expression and its efficiency is regulated by several factors.General significance
The control of selenoproteome expression is crucial for redox homeostasis and antioxidant defense of mammalian organisms. In this review, we summarize current knowledge on the co-translational insertion of selenocysteine into selenoproteins, and its layers of regulation. 相似文献3.
Background
The present study it is part of the study of the applications of biocompatible nanoparticles in a biological environment. Nowadays, in fact, nanoparticles are making it possible to reach surprising results in the field of biomaterials, drug delivery and their transport in the blood flux, as the use of the contrast medium for medical imaging and to be injected in tumors before to apply radio and thermal therapy. Nanoparticles modify the chemical and physical properties of solids, liquids, and gases and in particular of physiological liquids, soft and hard biological tissues.Methods
The present article focalizes on the role of Au nanoparticles for biological and medical applications in which their insertion in cells, tissues, and organs may improve the diagnostic imaging contrast with traditional X-ray imaging and the absorbed doses due to radio- and thermal-therapies. Their injection in the tissue, in fact, increases the effective atomic number of the tissue, thus the increment of the electron density of the medium causes higher radiation LET (linear energy transfer) with the increment of released dose and major effects of radiotherapy expositions.Main findings
The present paper shows the possibility to generate spherical gold nanoparticles with an average diameter of about 5 nm, pure and not agglomerated, biocompatible, stable and without the addition of chemical agents, by laser ablation of gold material in water. The solution can be directly injected in the extracellular liquid of cell cultures or directly in the blood flux of mice to be transported inside the complex living system. Here it is accumulated in specific organs in which the up-take and decay can be measured using suitable images of fluorescence of the organs of the mouse.Conclusions
The aim of this research is to transport the nanoparticles in places where tissue disease exists and reduce their concentration in healthy tissues. This permit a better observation of the diseased tissues and their preparation as targeting for radio- and thermal-therapy to be applied to damage tumor cells saving healthy tissues. 相似文献4.
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5.
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6.
Background
The anterior cruciate ligament rupture is a common injury which mainly affects young and active population. Faced to this problem, the development of synthetic structures for ligament reconstruction is increasing. The most recent researches focused on the development of biodegradable structures that could be functionalized to enhance host integration. This work describes the elaboration of different poly(ε-caprolactone) prototypes for the rat anterior cruciate ligament replacement in order to found the best design for further in vivo assays.Methods
According to the literature, it was decided to elaborate two different poly(ε-caprolactone) prototypes: a braided one and a free-fibers one. A chemical grafting of a bioactive polymer–poly(sodium styrene sulfonate) – was performed on both prototypes and mechanical and biological testing were assessed. Based on these results, one rat was implanted with the best prototype.Results
The mechanical and biological results demonstrated that the best prototype to implant was the poly(sodium styrene sulfonate)-grafted braided prototype. After one-month implantation, no inflammation was observable around the scar. The rat demonstrated good flexion and extension of the lower limb without any anterior drawer. The prototype was highly anchored to the bone. ESEM images of the explanted prototype showed the presence of cells and tissue ingrowth along and around the fibers.Conclusion
This work demonstrates the feasibility to implant a bioactive and biodegradable synthetic ligament in the rat model without any inflammation and with a good tissue anchoring at a short-term time. This will lead to an extensive in vivo assay. 相似文献7.
Marta Inglés Lucia Gimeno-Mallench Cristina Mas-Bargues Mar Dromant Raquel Cruz-Guerrero Francisco José García-García Leocadio Rodríguez-Mañas Juan Gambini Consuelo Borrás José Viña 《Revista espa?ola de geriatría y gerontología》2018,53(4):202-207
Introduction
The search for biomarkers that can lead to the early diagnosis and thus, early treatment of frailty, has become one of the main challenges facing the geriatric scientific community. The aim of the present study was to identify single nucleotide polymorphisms (SNPs) related to frailty.Material and methods
The study was conducted on 152 subjects from the Toledo Study for Healthy Aging (65 to 95 years of age), and classified as frail (n=78), and non-frail (n=74), according to Fried's criteria. After blood collection, DNA was isolated and amplified for the analysis of SNPs using AxiomTM Genotyping technology (Affymetrix). Statistical analyses were performed using the Plink program and library SNPassoc.Results
The results of the study showed 15 SNPs with a P < .001. Those SNPs involved in processes related to frailty, such as energy metabolism, regulation of biological processes, cell motility and integrity, and cognition are highlighted.Conclusions
These results suggest that the genetic variations identified in frail individuals that are involved in biological processes related to frailty may be considered as biomarkers for the early detection of frailty. 相似文献8.
Background
Epileptic seizures are unpredictable in nature and its quick detection is important for immediate treatment of patients. In last few decades researchers have proposed different algorithms for onset and offset detection of seizure using Electroencephalogram (EEG) signals.Methods
In this paper, a combined approach for onset and offset detection is proposed using Triadic wavelet decomposition based features. Standard deviation, variance and higher order moments, extracted as significant features to represent different EEG activities.Classification between seizure and non-seizure EEG was carried out using linear discriminant analysis (LDA) and k-nearest neighbour (KNN) classifiers. The method was tested using two benchmark EEG datasets in the field of seizure detection.CHBMIT EEG dataset was used for evaluating the performance of proposed seizure onset and offset detection method.Further for testing the robustness of the algorithm, the effect of the signal-to-noise ratio on the detection accuracy has been also investigated using Bonn University EEG dataset.Results
The seizure onset and offset detection method yielded classification accuracy, specificity and sensitivity of 99.45%, 99.62% and 98.36% respectively with 6.3 s onset and ?1.17 s offset latency using KNN classifier.The seizure detection method using Bonn University EEG dataset got classification accuracy of 92% when SNR = 5 dB, 94% when SNR = 10 dB, and 96% when SNR = 20 dB, while it also yielded 96% accuracy for noiseless EEG.Conclusion
The present study focuses on detection of seizure onset and offset rather than only seizure detection. The major contribution of this work is that the novel triadic wavelet transform based method is developed for the analysis of EEG signals. The results show improvement over other existing dyadic wavelet based Triadic techniques. 相似文献9.
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10.
Background
Mesenchymal stromal cells (MSCs) offer great potential for diverse clinical applications. However, conventional systemic infusion of MSCs limits their therapeutic benefit, since intravenously (IV) infused cells become entrapped in the lungs where their dwell time is short.Methods
To explore possible alternatives to IV infusion, we used in vivo optical imaging to track the bio-distribution and survival of 1 million bioluminescent MSCs administered IV, intraperitoneally (IP), subcutaneously (SC) and intramuscularly (IM) in healthy athymic mice.Results
IV-infused MSCs were undetectable within days of administration, whereas MSCs implanted IP or SC were only detected for 3 to 4 weeks. In contrast, MSCs sourced from human umbilical cord matrix or bone marrow survived more than 5 months in situ when administered IM. Long-term survival was optimally achieved using low passage cells delivered IM. However, MSCs could undergo approximately 30 doublings before their dwell time was compromised. Cryo-preserved MSCs administered IM promptly after thaw were predominantly cleared after 3 days, whereas equivalent cells cultured overnight prior to implantation survived more than 3 months.Discussion
The IM route supports prolonged cell survival of both neo-natal and adult-derived MSCs, although short-term MSC survival was comparable between all tested routes up to day 3. IM implantation presents a useful alternative to achieve clinical benefits from prolonged MSC dwell time at a homeostatic implant site and is a minimally invasive delivery route suitable for many applications. However, optimized thaw protocols that restore full biological potential of cryo-preserved MSC therapies prior to implantation must be developed. 相似文献11.
Water stress-induced xylem hydraulic failure is a causal factor of tree mortality in beech and poplar 总被引：1，自引：0，他引：1
Têtè Sévérien Barigah Olivia Charrier Marie Douris Marc Bonhomme Stéphane Herbette Thierry Améglio Régis Fichot Frank Brignolas Hervé Cochard 《Annals of botany》2013,112(7):1431-1437
Background and Aims
Extreme water stress episodes induce tree mortality, but the physiological mechanisms causing tree death are still poorly understood. This study tests the hypothesis that a potted tree''s ability to survive extreme monotonic water stress is determined by the cavitation resistance of its xylem tissue.Methods
Two species were selected with contrasting cavitation resistance (beech and poplar), and potted juvenile trees were exposed to a range of water stresses, causing up to 100 % plant death.Key Results
The lethal dose of water stress, defined as the xylem pressure inducing 50 % mortality, differed sharply across species (1·75 and 4·5 MPa in poplar and beech, respectively). However, the relationships between tree mortality and the degree of cavitation in the stems were similar, with mortality occurring suddenly when >90 % cavitation had occurred.Conclusions
Overall, the results suggest that cavitation resistance is a causal factor of tree mortality under extreme drought conditions. 相似文献12.
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13.
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14.
Background
Ultrasound plays an important role in cancer diagnosis. B-mode imaging and contrast-enhanced ultrasound are routinely used to detect cancerous lesions in breast and liver. The use of ultrasound contrast agents (UCAs) such as microbubbles (MBs), which can be functionalized with targeting ligands, has further enabled ultrasound molecular imaging (USMI) of specific molecular markers in pre-clinical and the first clinical studies. As targeted MBs have a diameter of 1–4 μm, they are limited to the blood vasculature upon intravenous injection, and can bind to markers of the vascular endothelium. USMI with targeted MBs was applied for imaging of markers of inflammation, angiogenesis, and the tumor endothelium.Aim
The present review provides an introduction to USMI and presents currently available UCAs, targeting strategies, pre-clinical targets, proposed applications, and the first clinical studies with USMI to guide novel users and assess the technique's potential for clinical use. 相似文献15.
K. Langlois H. Pillet F. Lavaste G. Rochcongar P. Rouch P. Thoreux W. Skalli 《IRBM》2018,39(4):251-260
Background
Several methods can be used to assess joint kinematics going from optoelectronic motion analysis to biplanar fluoroscopy. The aim of the present work was to evaluate the reliability of the use of biplane radiography to quantify the sequential 3D kinematics of the femoro-tibial joint.Methods
Bi-planar X-rays (EOS imaging) of 12 lower limbs (6 specimens in vitro and 6 subjects in vivo) were taken for various knee flexion angles. 3D personalized models of the femur and the tibia were registered on each pair of views. To quantify the bias, the kinematic parameters calculated from the registered models were compared to those obtained from the tripods embedded in the specimens. Intra and inter-operator repeatability of each parameter were assessed from the registrations made by 3 operators in vivo.Results
In vitro, the bias of the tibia pose estimation obtained from the registration method was inferior to 1.6 mm and 0.4°. In vivo, the repeatability of the sequential kinematic parameters was inferior to 0.3°, 2.1° and 1.8°, for respectively flexion, varus-valgus and medial-lateral rotation and inferior to 1.8 mm for translations.Conclusion
Compared to simple fluoroscopy, the accuracy of our method based on sequential images was of the same order of magnitude, with better results for the translation in the frontal plane. The low dose of radiation of the EOS system offers promising prospects for a clinical use of this method to assess the femoro-tibial sequential kinematics. 相似文献16.
Natalia Mota-Martorell Irene Pradas Mariona Jové Alba Naudí Reinald Pamplona 《Revista espa?ola de geriatría y gerontología》2019,54(2):88-93
Background
The glycerophospholipids, synthesised from diacylglycerol (DAG), are one of the main lipid components of cell membranes. The lipid profile is an optimised feature associated with animal longevity. In this context, the hypothesis is presented that the DAG biosynthesis rate, and thus, the glycerophospholipids content, is related to animal longevity.Material and methods
A plasma lipidomic analysis was performed based on the mass spectrometry of 11 mammalian species with a maximum longevity ranging from 3.5 to 120 years. Lipid identification was based on exact mass, retention time, and isotopic distribution. ANOVA test was applied to differentiate the lipids between animal species. The relationship between these lipids and longevity was carried out with a Spearman correlation. Data was analysed using SPSS and MetaboAnalyst.Results
Among the 1,061 different lipid molecular species found between species, 47 were defined as DAG. Interestingly, 14 of them showed a negative correlation with mammalian maximum longevity. Multivariate statistics revealed that 14 DAGs were enough to define mammalian species and their maximum longevity.Conclusions
Data suggest that long-lived mammalian species have a lower rate of glycerophospholipids synthesis through the de novo pathway, possibly associated with a lower rate of membrane lipid exchange, which in turn is related to lower energy expenditure. 相似文献17.
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18.
Carla Toyas Miazza Rosa María Martínez-Álvarez Jesús Díez-Manglano Ana Isabel Ezpeleta Galindo María Elena Laín Miranda Carmen Aspiroz Sancho 《Revista espa?ola de geriatría y gerontología》2018,53(5):262-267
Introduction
The limitation of therapeutic effort (LTE) depends on medical, ethical and individual factors. We describe the characteristics of patients with bacteremia in which it was decided to limit the therapeutic effort.Method
Prospective study of bacteremia in a community hospital in 2011. We collected information regarding patient variable (age, sex, Barthel index, comorbidities, Charlson Index and exogenous factors) as well as regarding the infectious episode (etiology, focus, place of adquisition, clinical expressivity, LTE and hospital mortality). The group in which LTE was performed was compared to the one that was not.Results
We collected 233 episodes of bacteremia in 227 patients. We performed LTE in 19 patients (8.2%). Patients with LTE were older (80.7 vs. 72.6 years, p=.014), had more comorbidity (Charlson index 4.6 vs. 2.1, p<.001 and most frequently were severe dependents (57.9% vs. 18.8%, p<.001). We found no association with sex, place of adquisition or clinical expressivity. The commonest clinical focus in patients with LTE was the urinary (42.1%) and there was a predominance of gram positive bacteria (63.2%). The empirical treatment was started early in 73.7% of cases. All patients except one died.Conclusion
LTE is considered in an important number of patients with bacteremia. They usually are older, with more comorbidity and functional dependence, bad functional basal status and important comorbidity. Knowing their differential characteristics allow us to understand this decision. 相似文献19.
Hua Deng Prashanta Dutta Jin Liu 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(9):2104-2111
Background
Receptor dependent clathrin-mediated endocytosis (CME) is one of the most important endocytic pathways for the internalization of bioparticles into cells. During CME, the ligand-receptor interactions, development of clathrin-coated pit (CCP) and membrane evolution all act together to drive the internalization of bioparticles. In this work, we develop a stochastic computational model to investigate the CME based on the Metropolis Monte Carlo simulations.Methods
The model is based on the combination of a stochastic particle binding model with a membrane model. The energetic costs of membrane bending, CCP formation and ligand-receptor interactions are systematically linked together.Results
We implement our model to investigate the effects of particle size, ligand density and membrane stiffness on the overall process of CME from the drug delivery perspectives. Consistent with some experiments, our results show that the intermediate particle size and ligand density favor the particle internalization. Moreover, our results show that it is easier for a particle to enter a cell with softer membrane.Conclusions
The model presented here is able to provide mechanistic insights into CME and can be readily modified to include other important factors, such as actins. The predictions from the model will aid in the therapeutic design of intracellular/transcellular drug delivery and antiviral interventions. 相似文献20.