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Biological Tissues (biological + tissue)
Selected AbstractsMiniaturization of Fluorescence Microscopes Using Fibre OpticsEXPERIMENTAL PHYSIOLOGY, Issue 6 2002Fritjof Helmchen In both medical research and diagnostics characterization of biological tissue on the cellular level relies on high-resolution optical microscopy. In most cases, however, tissue is excised for microscopic investigation, in part because conventional microscopes are bulky instruments. Imaging of cells in the intact living organism has been difficult. Over the last decade several groups have developed miniature confocal microscopes that use fibre optics to deliver light to the specimen and to measure either reflected or excited fluorescence light. In addition, two-photon excitation recently has been employed in a small portable ,fibrescope'. A potential clinical application of these microscope probes is their endoscopic use for optical biopsy of inner organs or guidance of conventional biopsy. As a mobile research tool they may permit imaging of neuronal activity in the brain of awake, behaving animals. Here, we review technological approaches to build miniaturized fluorescence microscopes and discuss their potential applications. [source] Chitosan/Gold Nanocomposites: Chitosan Films Doped with Gold Nanorods as Laser-Activatable Hybrid Bioadhesives (Adv. Mater.ADVANCED MATERIALS, Issue 38 201038/2010) The cover image represents an inside view of a laser-activated gold nanorod/chitosan film. Gold nanorods dispersed throughout the polymeric chitosan matrix absorb incident near-infrared laser light. The photothermal conversion from the gold nanorods activates the surrounding chitosan strands to mediate functional adhesion with biological tissue, as discussed in work reported on p. 4313 by Paolo Matteini and co-workers. [source] Chitosan Films Doped with Gold Nanorods as Laser-Activatable Hybrid BioadhesivesADVANCED MATERIALS, Issue 38 2010Paolo Matteini Biocompatible chitosan/gold nanorods films are fabricated and tested as laser-activatable adhesives. When exposed to near-infrared laser light the nanoparticles carry out efficient photothermal conversion, which activates the polar groups of chitosan strands and mediates functional adhesion with a biological tissue. This technology may enable a number of key applications in medicine including tissue repair, wound dressing and drug delivery. [source] Computational methods for optical molecular imagingINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 12 2009Duan Chen Abstract A new computational technique, the matched interface and boundary (MIB) method, is presented to model the photon propagation in biological tissue for the optical molecular imaging. Optical properties have significant differences in different organs of small animals, resulting in discontinuous coefficients in the diffusion equation model. Complex organ shape of small animal induces singularities of the geometric model as well. The MIB method is designed as a dimension splitting approach to decompose a multidimensional interface problem into one-dimensional ones. The methodology simplifies the topological relation near an interface and is able to handle discontinuous coefficients and complex interfaces with geometric singularities. In the present MIB method, both the interface jump condition and the photon flux jump conditions are rigorously enforced at the interface location by using only the lowest-order jump conditions. This solution near the interface is smoothly extended across the interface so that central finite difference schemes can be employed without the loss of accuracy. A wide range of numerical experiments are carried out to validate the proposed MIB method. The second-order convergence is maintained in all benchmark problems. The fourth-order convergence is also demonstrated for some three-dimensional problems. The robustness of the proposed method over the variable strength of the linear term of the diffusion equation is also examined. The performance of the present approach is compared with that of the standard finite element method. The numerical study indicates that the proposed method is a potentially efficient and robust approach for the optical molecular imaging. Copyright © 2008 John Wiley & Sons, Ltd. [source] Holographic digital Fourier microscopy for selective imaging of biological tissueINTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 6 2004Sergey A. Alexandrov Abstract We present an application of digital Fourier holography for selective imaging of scatterers with different sizes in turbid media such as biological tissues. A combination of Fourier holography and high-resolution digital recording, digital Fourier microscopy (DFM) permits crucial flexibility in applying filtering to highlight scatterers of interest in the tissue. The high-resolution digital hologram is a result of the collation of Fourier holographic frames to form a large-size composite hologram. It is expected that DFM has an improved signal-to-noise ratio as compared to conventional direct digital imaging, e.g., phase microscopy, as applied to imaging of small-size objects. The demonstration of the Fourier filtering capacity of DFM using a biological phantom represents the main focus of this article. © 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 14, 253,258, 2004; Published online inWiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20031 [source] Stabilization of collagen by the plant polyphenolics Acacia mollissima and Terminalia chebulaJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008G. Krishnamoorthy Abstract The central role of collagen as the major structural fibrous protein in the mammalian extracellular matrix has motivated a significant effort toward the determination of its mechanical properties at all levels, ranging from single monomers and long-chain polymers to a structural element within a biological tissue. However, the stabilization of collagen against collagenolytic degradation finds significance in biomedical and industrial applications. Tannins are plant-derived polyphenols that have the ability to inhibit the collagenase activity at minimum concentration. The inhibitory effect of wattle (Acacia mollissima) and myrobalan (Terminalia chebula) on the action of collagenase against collagen was probed in this study. The kinetics of the inhibition of collagenase by wattle and myrobalan was deduced from the extent of hydrolysis of 2-furanacryloyl,L -leucyl,glycyl,L -prolyl,L -alanine. Both wattle and myrobalan tannin exhibited competitive modes of inhibition against collagenase. Circular dichroism studies of collagenase on treatment with wattle and myrobalan revealed changes in the secondary structure of collagenase. These results suggest that the tannins of A. mollissima and T. chebula extracts facilitated collagen stabilization through collagenase inhibition. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Raman spectroscopic analysis of breast cancer tissues: identifying differences between normal, invasive ductal carcinoma and ductal carcinoma in situ of the breast tissueJOURNAL OF RAMAN SPECTROSCOPY, Issue 10 2007Shazza Rehman Abstract A relatively non-destructive method employing Raman spectroscopy for the analysis of histopathological specimens is described. Raman spectroscopy has allowed qualitative analysis of the same specimen used for histopathological evaluation. Breast cancer tissues have been analysed to demonstrate the feasibility of the chemical changes taking place in the biological tissue, which can be identified precisely, and the results are reproducible. Raman analysis of tissue sections provides distinct spectra that can be used to distinguish between the nuclear grades of ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC) of the breast. Sixty cases of breast carcinoma including DCIS and IDC and seven cases of normal breast tissues were studied employing the Raman spectroscopic technique. This study reports for the first time spectral differences between DCIS grades. It is concluded that Raman spectroscopy can objectively distinguish between DCIS and IDC grades and is non-destructive and reproducible. It should become possible in future to use Raman spectroscopy as an informative and quantitative method suitable for classification of grades and diagnosis of breast carcinoma. Copyright © 2007 John Wiley & Sons, Ltd. [source] MICROMECHANICS: SIMULATING THE ELASTIC BEHAVIOR OF ONION EPIDERMIS TISSUEJOURNAL OF TEXTURE STUDIES, Issue 1 2006JIMMY LOODTS ABSTRACT A generic modeling approach is introduced that allows for dynamical simulations of cellular biological tissue. It is derived from the discrete element approach in the sense that the tissue is discretized such that histological aspects like cell geometry and the cellular arrangement within the tissue can be fully incorporated into the model. This makes dynamical simulations of arbitrarily shaped cellular tissues feasible in an elegant and a robust way. The validity of this simulation technique is demonstrated by a case study on the unicellular epidermis layer of onion (Allium cepa). The parameters of a two-dimensional model are determined using published stress,strain data from a tension test on longitudinal strips. The model is then validated quantitatively against the data for transversal strips. [source] Human liver autofluorescence: An intrinsic tissue parameter discriminating normal and diseased conditions,,LASERS IN SURGERY AND MEDICINE, Issue 5 2010Anna C. Croce PhD Abstract Background and Objective Autofluorescence (AF) emission is an intrinsic parameter that can provide real-time information on morpho-functional properties of biological tissue, being strictly related with their biochemical composition and structural organization. The diagnostic potentials of AF-based techniques have been investigated on normal, fibrotic, and steatotic liver tissues, in reference to histological features as evidenced by specific histochemical stainings. Materials and Methods AF emission under excitation at 366,nm has been examined on cryostatic tissue sections obtained from biopsies collected during surgical operation, by means of fluorescence imaging and microspectrofluorometric techniques. Results NAD(P)H, collagen, and vitamin A were found to be the endogenous fluorophores characterizing normal, fibrotic, and steatotic liver tissue AF, respectively. The differences of their photo-physical properties, in terms of emission amplitude, spectral shape, and response to irradiation, give rise to modifications of overall AF signal collected from tissues that allow the liver conditions to be distinguished. Conclusion The study provides a valid premise for a development of AF-based optical biopsy techniques for a real-time discrimination of liver anatomo-pathological patterns. Lasers Surg. Med. 42:371-378, 2010. © 2010 Wiley-Liss, Inc. [source] Near-infrared photo-excited emission from tissues treated at different temperature levelsLASERS IN SURGERY AND MEDICINE, Issue 1 2001Jing Tang MD Abstract Background and Objective There is a lack of methods to evaluate the extent of thermal treatment of biological tissue. The intensity of the near-infrared (NIR) emission photo-excitation was investigated from tissue undergoing different levels of heat treatment. Study Design/Materials and Methods Chicken muscle was heated in an oven at different temperature levels ranging from 40°C until burn-off. The spectral emission intensity from these heat-treated tissues was measured with a CCD camera and the intensity was calculated. Results The emission intensity increased proportionally with respect to the extent of treatment temperature until burning. Linear relationships between treatment temperature and the emission intensity from tissue samples were found in three temperature ranges: from 40 to 160°C, from 165 to 220°C, and from 225 to 250°C. Conclusions The change in tissue damage after heat treatment could be detected by measuring the NIR emission intensity from the thermally damaged tissues. Lasers Surg. Med. 29:18,22, 2001. © 2001 Wiley-Liss, Inc. [source] On a hierarchy of models for electrical conduction in biological tissuesMATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 7 2006M. Amar Abstract In this paper we derive a hierarchy of models for electrical conduction in a biological tissue, which is represented by a periodic array of period , of conducting phases surrounded by dielectric shells of thickness ,, included in a conductive matrix. Such a hierarchy will be obtained from the Maxwell equations by means of a concentration process , , 0, followed by a homogenization limit with respect to ,. These models are then compared with regard to their physical meaning and mathematical issues. Copyright © 2005 John Wiley & Sons, Ltd. [source] Biomedical applications of 10B and 11B NMRNMR IN BIOMEDICINE, Issue 2 2005Peter Bendel Abstract This review focuses mainly on the detection and investigation of molecules used for boron neutron capture therapy (BNCT) by 10B and 11B NMR. In this binary radiation treatment, boron-containing molecules (also called ,BNCT agents') enriched in the 10B isotope, are targeted to the tumor, and irradiated with thermal or epithermal neutrons. Capture of these neutrons by 10B nuclei generates cell-damaging radiation, confined to single cell dimensions. NMR research efforts have primarily been applied in two directions: first, to investigate the metabolism and pharmaco-kinetics of BNCT agents in-vivo, and second, to use localized NMR spectroscopy and/or MRI for non-invasive mapping of the administered molecules in treated animals or patients. While the first goal can be pursued using 11B NMR for natural-abundance samples (80% 11B / 20% 10B), molecules used in the actual treatment are >,95% enriched in 10B, and must therefore be detected by 10B NMR. Both 10B (spin 3) and 11B (spin 3/2) are quadrupolar nuclei, and their typical relaxation times, in common BNCT agents in biological environments, are rather short. This poses some technical challenges, particularly for MRI, which will be reviewed, along with possible solutions. The first attempts at 11B NMR and MRI detection of BNCT agents in biological tissue were conducted over a decade ago. Since then, results from 11B MRI in laboratory animals and in humans have been reported, and 11B NMR spectroscopy provided interesting and unique information about the metabolism of some BNCT agents in cultured cells. 10B NMR was applied either ,indirectly' (in double-resonance experiments involving coupled protons), but also by direct 10B MRI in mice. However, no results involving the NMR detection of 10B-enriched compounds in treated patients have been reported yet. Copyright © 2005 John Wiley & Sons, Ltd. [source] Contactless passive diagnosis for brain intracranial applications: A study using dielectric matching materialsBIOELECTROMAGNETICS, Issue 5 2010Ioannis A. Gouzouasis Abstract A prototype system for passive intracranial monitoring using microwave radiometry is proposed. It comprises an ellipsoidal conductive wall cavity to achieve beamforming and focusing, in conjunction with sensitive multiband receivers for detection. The system has already shown the capability to provide temperature and/or conductivity variations in phantoms and biological tissue. In this article, a variant of the initially constructed modality is theoretically and experimentally investigated. Specifically, dielectric matching materials are used in an effort to improve the system's focusing attributes. The theoretical study investigates the effect of dielectric matching materials on the system's detection depth, whereas measurements with phantoms focus on the investigation of the system's detection level and spatial resolution. The combined results suggest that the dielectric matching layers lead to the improvement of the system's detection depth and temperature detection level. Also, the system's spatial resolution is explored at various experimental setups. Theoretical and experimental results conclude that with the appropriate combination of operation frequencies and dielectric layers, it is possible to monitor areas of interest inside human head models with a variety of detection depths and spatial resolutions. Bioelectromagnetics 31:335,349, 2010. © 2010 Wiley-Liss, Inc. [source] Bayesian Shrinkage Estimation of the Relative Abundance of mRNA Transcripts Using SAGEBIOMETRICS, Issue 3 2003Jeffrey S. Morris Summary. Serial analysis of gene expression (SAGE) is a technology for quantifying gene expression in biological tissue that yields count data that can be modeled by a multinomial distribution with two characteristics: skewness in the relative frequencies and small sample size relative to the dimension. As a result of these characteristics, a given SAGE sample may fail to capture a large number of expressed mRNA species present in the tissue. Empirical estimators of mRNA species' relative abundance effectively ignore these missing species, and as a result tend to overestimate the abundance of the scarce observed species comprising a vast majority of the total. We have developed a new Bayesian estimation procedure that quantifies our prior information about these characteristics, yielding a nonlinear shrinkage estimator with efficiency advantages over the MLE. Our prior is mixture of Dirichlets, whereby species are stochastically partitioned into abundant and scarce classes, each with its own multivariate prior. Simulation studies reveal our estimator has lower integrated mean squared error (IMSE) than the MLE for the SAGE scenarios simulated, and yields relative abundance profiles closer in Euclidean distance to the truth for all samples simulated. We apply our method to a SAGE library of normal colon tissue, and discuss its implications for assessing differential expression. [source] Society of Academic and Research SurgeryBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 5 2003Article first published online: 30 APR 200 The following 98 abstracts were presented to the 3rd meeting of the Society of Academic and Research Surgery in January 2003. The meeting was held at the Royal Armouries Museum, Leeds and was hosted by Professor Pierre Guillou and his colleagues at the St James's University Hospital and University of Leeds. The Patey prize was won by M. C. J. Button et al. for a paper entitled ,The enzymatic extraction of adult human venous smooth muscle cells and their incorporation into a wholly biological tissue engineered arterial bypass conduit'. Copyright © 2003 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source] Electrochemical Nitric Oxide Sensors for Biological Samples , Principle, Selected Examples and ApplicationsELECTROANALYSIS, Issue 1 2003Fethi Bedioui Abstract The discoveries made in the 1980s that NO could be synthesized by mammalian cells and could act as physiological messenger and cytotoxic agent had elevated the importance of its detection. The numerous properties of NO, that enable it to carry out its diverse functions, also present considerable problems when attempting its detection and quantification in biological systems. Indeed, its total free concentration in physiological conditions has been established to be in nanomolar range. Thus, detection of nitric oxide remains a challenge, pointing out the difficult dual requirements for specificity and sensitivity. Exception made for the electrochemical techniques, most of the approaches (namely UV-visible spectroscopy, fluorescence, electron paramagnetic resonance spectroscopy) use indirect methods for estimating endogenous NO, relying on measurements of secondary species such as nitrite and nitrate or NO-adducts. They also suffer from allowing only ex situ measurements. So, the only strategies that allow a direct and in vivo detection of NO are those based on the use of ultramicroelectrodes. The reality is that surface electrode modification is needed to make the ultramicroelectrode material selective for NO. Therefore, the design of modified electrode surfaces using organized layers is very attractive and provides the ideal strategy. This review addresses a global description of the various approaches that have involved chemically modified microelectrodes specially designed for the electrochemical detection of NO in biological media. Selected significant examples of applications in biological tissues are also reported in order to highlight the importance of this approach in having new insights into the modulatory role of NO in physiology and pathophysiology. [source] Speciation of arsenic compounds in fish and oyster tissues by capillary electrophoresis-inductively coupled plasma-mass spectrometryELECTROPHORESIS, Issue 7-8 2005Ching-Fen Yeh Abstract A capillary electrophoresis-inductively coupled plasma-mass spectrometric (CE-ICP-MS) method for the speciation of six arsenic compounds, namely arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid, dimethylarsinic acid, arsenobetaine and arsenocholine is described. The separation has been achieved on a 70,cm length×75,µm,ID fused-silica capillary. The electrophoretic buffer used was 15,mM Tris (pH,9.0) containing 15,mM sodium dodecyl sulfate (SDS), while the applied voltage was set at +22,kV. The arsenic species in biological tissues were extracted into 80%,v/v methanol-water mixture, put in a closed centrifuge tube and kept in a water bath, using microwaves at 80°C for 3,min. The extraction efficiencies of individual arsenic species added to the sample at 0.5,µg As/g level were between 96% and 107%, except for As(III), for which it was 89% and 77% for oyster and fish samples, respectively. The detection limits of the species studied were in the range 0.3,0.5,ng As/mL. The procedure has been applied for the speciation analysis of two reference materials, namely dogfish muscle tissue (NRCC DORM-2) and oyster tissue (NIST SRM 1566a), and two real-world samples. [source] 980-nm Laser-Driven Photovoltaic Cells Based on Rare-Earth Up-Converting Phosphors for Biomedical ApplicationsADVANCED FUNCTIONAL MATERIALS, Issue 23 2009Zhigang Chen Abstract A prerequisite for designing and constructing wireless biological nanorobots is to obtain an electrical source that is continuously available in the operational biological environment. Herein the first preparation of 980-nm laser-driven photovoltaic cells (980LD-PVCs) by introducing of a film of rare-earth up-converting nanophosphors in conventional dye-sensitized solar cells is reported. Under the irradiation of a 980-nm laser with a power of 1,W, the visible up-converting luminescence of rare-earth nanophosphors can be efficiently absorbed by the dyes in 980LD-PVCs so that they exhibit a maximal output power of 0.47 mW. In particular, after being covered with 1 to 6 layers of pig intestines (thickness: ca. 1,mm per layer) as a model of biological tissues, 980LD-PVCs still possess a maximal output power of between 0.28 and 0.02,mW, which is efficient enough to drive many kinds of biodevices. This research opens up the possibility of preparing and/or developing novel electrical sources for wireless biological nanorobots and many other biodevices. [source] Holographic digital Fourier microscopy for selective imaging of biological tissueINTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 6 2004Sergey A. Alexandrov Abstract We present an application of digital Fourier holography for selective imaging of scatterers with different sizes in turbid media such as biological tissues. A combination of Fourier holography and high-resolution digital recording, digital Fourier microscopy (DFM) permits crucial flexibility in applying filtering to highlight scatterers of interest in the tissue. The high-resolution digital hologram is a result of the collation of Fourier holographic frames to form a large-size composite hologram. It is expected that DFM has an improved signal-to-noise ratio as compared to conventional direct digital imaging, e.g., phase microscopy, as applied to imaging of small-size objects. The demonstration of the Fourier filtering capacity of DFM using a biological phantom represents the main focus of this article. © 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 14, 253,258, 2004; Published online inWiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20031 [source] A new experimental station for simultaneous X-ray microbeam scanning for small- and wide-angle scattering and fluorescence at BESSY IIJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2007Oskar Paris A new instrument for simultaneous microbeam small- and wide-angle X-ray scattering and X-ray fluorescence (SAXS/WAXS/XRF) is presented. The instrument is installed at the microfocus beamline at BESSY II and provides a beam of 10,µm size with a flux of about 109 photons,s,1. A SAXS resolution up to 500,Ĺd -spacing and a range of scattering vectors of almost three orders of magnitude are reached by using a large-area high-resolution CCD-based detector for simultaneous SAXS/WAXS. The instrument is particularly suited for scanning SAXS/WAXS/XRF experiments on hierarchically structured biological tissues. The necessary infrastructure, such as a cryo-stream facility and an on-site preparation laboratory for biological specimens, are available. [source] Monitoring of glucose permeability in monkey skin in vivo using Optical Coherence TomographyJOURNAL OF BIOPHOTONICS, Issue 1-2 2010Mohamad G. Ghosn Abstract Topical trans-dermal delivery of drugs has proven to be a promising route for treatment of many dermatological diseases. The aim of this study is to monitor and quantify the permeability rate of glucose solutions in rhesus monkey skin noninvasively in vivo as a primate model for drug diffusion. A time-domain Optical Coherence Tomography (OCT) system was used to image the diffusion of glucose in the skin of anesthetized monkeys for which the permeability rate was calculated. From 5 experiments on 4 different monkeys, the permeability for glucose-20% was found to be (4.41 ± 0.28) 10,6 cm/sec. The results suggest that OCT might be utilized for the noninvasive study of molecular diffusion in the multilayered biological tissues in vivo. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] UBIQUINONE-10 AS AN ANTIOXIDANT,JOURNAL OF FOOD BIOCHEMISTRY, Issue 2 2008DAVID PETILLO ABSTRACT Ubiquinol, the reduced form of coenzyme Q, is known as a lipid antioxidant. Its fully oxidized form, ubiquinone, would theoretically not have this activity. However, we report that ubiquinone-10, the oxidized form of coenzyme Q, demonstrated antioxidant activity in model studies against a lipid-soluble free radical generator, 2,2,-azobis(2,4-dimethylvaleronitrile). This was demonstrated at both 1:100 and 1:1,000 ratios of ubiquinone-10 to lipid (for both methyl linoleate and methyl linolenate). Ubiquinone-10 should therefore not be discounted as a possible antioxidant in more complex systems such as food. PRACTICAL APPLICATIONS Coenzyme Q (ubiquinol/ubiquinone) is an important component of electron transport in biological tissues and is also classified as a potent antioxidant. It is generally believed that the form that is active as an antioxidant is the reduced ubiquinol. In evaluating the loss of antioxidants in mackerel light and dark muscle tissues, it was observed that the oxidized form, ubiquinone, comprised over 87% of the total coenzyme Q in light muscle and over 93% in dark muscle and this observation did not change under anaerobic conditions. This study was done to determine if the oxidized form of coenzyme Q, ubiquinone, was capable of acting as an antioxidant. In this study, it is shown that it can function in this manner. [source] Microneurography of human median nerveJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 6 2005Mehmet Bilgen PhD Abstract Purpose To examine the possibility of performing high-resolution MRI (microneurography) on peripheral nerves. Materials and Methods A specific radio frequency (RF) coil was developed to probe the human median nerve at a magnetic field strength of 9.4 T and tested on three excised samples by acquiring microneurograms. Results The microneurograms revealed neuronal tissue constituents at subfascicular level. The contrast features on proton-density and T1- and T2-weighted images were described and compared. The microscopic water movement was quantified using diffusion weighting parallel and orthogonal to the neuronal fiber orientation. The characteristics of anisotropic diffusion in the median nerve were comparable to those reported from other biological tissues (white matter and kidney). Conclusion The results overall suggest that microneurography might provide new noninvasive insights into microscopic gross anatomy of the peripheral nerve, injury evaluation, and efficacy of repair, although the feasibility at current clinically relevant field strengths is yet to be determined. J. Magn. Reson. Imaging 2005;21:826,830. © 2005 Wiley-Liss, Inc. [source] A new human catalytic antibody Se-scFv-2D8 and its selenium-containing single domains with high GPX activityJOURNAL OF MOLECULAR RECOGNITION, Issue 4 2010Junjie Xu Abstract Glutathione peroxidase (GPX) is a well-known antioxidant selenoenzyme, which can catalyze the reduction of a variety of hydroperoxides and consequently protect cells and other biological tissues against oxidative damage. Many attempts have been made to mimic its function, and a human catalytic antibody Se-scFv-B3 with GPX activity has been prepared in our previous study. This time, a new clone 2D8 that bound specifically to the glutathione analog GSH-S-DNPBu was selected again by using the technology of phage display antibody library, and then scFv-2D8 was successfully expressed in soluble form and purified using Ni2+ -immobilized metal affinity chromatography. After being converted into selenium-containing scFv by chemically modification, it showed higher GPX activity than previous abzyme Se-scFv-B3. The heavy chain variable fragment of scFv-2D8 was also prepared and converted into selenium-containing protein using the same method. This selenium-containing single-domain antibody showed some GPX activity and, to the best of our knowledge, is the first human single-domain abzyme with GPX activity, which lays a foundation for preparing GPX abzyme with human origin, lower molecular weight and higher activity. Copyright © 2009 John Wiley & Sons, Ltd. [source] Center for Synchrotron Biosciences' U2B beamline: an international resource for biological infrared spectroscopyJOURNAL OF SYNCHROTRON RADIATION, Issue 4 2002N. S. Marinkovic A synchrotron infrared (IR) beamline, U2B, dedicated to the biomedical and biological sciences has been constructed and is in operation at the National Synchrotron Light Source (NSLS) of Brookhaven National Laboratory. The facility is operated by the Center for Synchrotron Biosciences of the Albert Einstein College of Medicine in cooperation with the NSLS. Owing to the broadband nature of the synchrotron beam with brightness 1000 times that of conventional sources, Fourier transform IR spectroscopy experiments are feasible on diffraction-limited sample areas at high signal-to-noise ratios and with relatively short data-acquisition times. A number of synchrotron IR microscopy experiments that have been performed in the mid-IR spectral range (500,5000,cm,1) are summarized, including time-resolved protein-folding studies in the microsecond time regime, IR imaging of neurons, bone and other biological tissues, as well as imaging of samples of interest in the chemical and environmental sciences. Owing to the high flux output of this beamline in the far-IR region (50,500,cm,1), investigations of hydrogen bonding and dynamic molecular motions of biomolecules have been carried out from 10 to 300,K using a custom-made cryostat and an evacuated box. This facility is intended as an international resource for biological IR spectroscopy fully available to outside users based on competitive proposal. [source] Determination of chemical agent optical clearing potential using in vitro human skin,LASERS IN SURGERY AND MEDICINE, Issue 2 2005Bernard Choi PhD Abstract Background and Objectives: Optical clearing is a method that temporarily reduces the optical scattering of biological tissues. Study Design/Materials and Methods: To determine the optical clearing potential (OCP) of various chemical agents, we examined the change in reduced scattering coefficients of in vitro human skin after application directly to the dermal side. Results/Conclusions: We found that the mean agent OCP did not correlate with refractive index or osmolality. Lipophilic hyperosmotic agents had a mean OCP less than unity, indicating increased optical scattering. © 2005 Wiley-Liss, Inc. [source] NMR methods applied to anisotropic diffusionMAGNETIC RESONANCE IN CHEMISTRY, Issue 13 2002István Furó Abstract The methodology of NMR experiments intended to measure anisotropic diffusion is reviewed. Experiments of this kind preferably require oriented samples and/or orientation-dependent spin coupling and/or magnetic field gradients in different directions. One strategy of diffusion experiments in anisotropic systems with broad NMR lines employs line narrowing techniques, thereby allowing for efficient gradient encoding/decoding. Depending on the nuclei, spin couplings and samples, the preferred methods vary from decoupling through echo techniques to magic angle sample orientation and spinning. Another avenue to efficient gradient encoding/decoding is through very strong magnetic field gradients. Either way, anisotropic diffusion reveals new structural features as illustrated by a few selected examples in liquid crystals and in biological tissues. Copyright © 2002 John Wiley & Sons, Ltd. [source] Mass spectrometry in bioinorganic analytical chemistryMASS SPECTROMETRY REVIEWS, Issue 2 2006Ryszard Abstract A considerable momentum has recently been gained by in vitro and in vivo studies of interactions of trace elements in biomolecules due to advances in inductively coupled plasma mass spectrometry (ICP MS) used as a detector in chromatography and capillary and planar electrophoresis. The multi-isotopic (including non-metals such as S, P, or Se) detection capability, high sensitivity, tolerance to matrix, and large linearity range regardless of the chemical environment of an analyte make ICP MS a valuable complementary technique to electrospray MS and MALDI MS. This review covers different facets of the recent progress in metal speciation in biochemistry, including probing in vitro interactions between metals and biomolecules, detection, determination, and structural characterization of heteroatom-containing molecules in biological tissues, and protein monitoring and quantification via a heteroelement (S, Se, or P) signal. The application areas include environmental chemistry, plant and animal biochemistry, nutrition, and medicine. © 2005 Wiley Periodicals, Inc. Mass Spec Rev 25:255,289, 2006 [source] On a hierarchy of models for electrical conduction in biological tissuesMATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 7 2006M. Amar Abstract In this paper we derive a hierarchy of models for electrical conduction in a biological tissue, which is represented by a periodic array of period , of conducting phases surrounded by dielectric shells of thickness ,, included in a conductive matrix. Such a hierarchy will be obtained from the Maxwell equations by means of a concentration process , , 0, followed by a homogenization limit with respect to ,. These models are then compared with regard to their physical meaning and mathematical issues. Copyright © 2005 John Wiley & Sons, Ltd. [source] Signal transduction in Mimosa pudica: biologically closed electrical circuitsPLANT CELL & ENVIRONMENT, Issue 5 2010ALEXANDER G. VOLKOV ABSTRACT Biologically closed electrical circuits operate over large distances in biological tissues. The activation of such circuits can lead to various physiological and biophysical responses. Here, we analyse the biologically closed electrical circuits of the sensitive plant Mimosa pudica Linn. using electrostimulation of a petiole or pulvinus by the charged capacitor method, and evaluate the equivalent electrical scheme of electrical signal transduction inside the plant. The discharge of a 100 µF capacitor in the pulvinus resulted in the downward fall of the petiole in a few seconds, if the capacitor was charged beforehand by a 1.5 V power supply. Upon disconnection of the capacitor from Ag/AgCl electrodes, the petiole slowly relaxed to the initial position. The electrical properties of the M. pudica were investigated, and an equivalent electrical circuit was proposed that explains the experimental data. [source] | ||||||||||||||||||||||||||||||||||