Tissue Differentiation

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Dean J Bacich - One of the best experts on this subject based on the ideXlab platform.

  • moderate expression of prostate specific membrane antigen a Tissue Differentiation antigen and folate hydrolase facilitates prostate carcinogenesis
    Cancer Research, 2008
    Co-Authors: Veronica Yao, Anil V Parwani, Christoph Maier, Warren D W Heston, Dean J Bacich
    Abstract:

    Increased expression of PSMA, a Differentiation antigen with folate hydrolase activity, is an independent marker of prostate cancer progression. Mice expressing moderate levels of human PSMA in their prostate develop PIN-like lesions by 9 months. The aim of this study was to determine whether PSMA is involved in prostate carcinogenesis and progression and, if so, the possible mechanism by which PSMA may exert its effects. Using prostates from PSMA-transgenic mice, we developed a Tissue recombinant model that exhibits small atypical glands with features of adenocarcinoma. This was not observed in Tissue recombinants that were composed of prostate Tissues from the wild-type siblings. Cells from PSMA-transgenic Tissue recombinants have the ability to form colonies in semisolid agar. PSMA may facilitate this phenotype by increasing the invasive ability of cells. Ectopic PSMA expression on PC-3 cells increased the invasive capacity of cells in in vitro invasion assays, which could be competed out by folic acid. These results suggest PSMA facilitates the development of prostate cancer, and the invasive ability of these cells may be modulated by folate levels. These findings show a novel mechanism that may contribute to the known role of folate in cancer prevention, and may lead to the use of PSMA inhibitors as novel chemopreventive agents for prostate cancer. Moreover, our model should prove useful for further dissecting pathways involved in prostate carcinogenesis and progression.

  • moderate expression of prostate specific membrane antigen a Tissue Differentiation antigen and folate hydrolase facilitates prostate carcinogenesis
    Cancer Research, 2008
    Co-Authors: Veronica Yao, Anil V Parwani, Christoph Maier, Warren D W Heston, Dean J Bacich
    Abstract:

    Increased expression of PSMA, a Differentiation antigen with folate hydrolase activity, is an independent marker of prostate cancer progression. Mice expressing moderate levels of human PSMA in their prostate develop PIN-like lesions by 9 months. The aim of this study was to determine whether PSMA is involved in prostate carcinogenesis and progression and, if so, the possible mechanism by which PSMA may exert its effects. Using prostates from PSMA-transgenic mice, we developed a Tissue recombinant model that exhibits small atypical glands with features of adenocarcinoma. This was not observed in Tissue recombinants that were composed of prostate Tissues from the wild-type siblings. Cells from PSMA-transgenic Tissue recombinants have the ability to form colonies in semisolid agar. PSMA may facilitate this phenotype by increasing the invasive ability of cells. Ectopic PSMA expression on PC-3 cells increased the invasive capacity of cells in in vitro invasion assays, which could be competed out by folic acid. These results suggest PSMA facilitates the development of prostate cancer, and the invasive ability of these cells may be modulated by folate levels. These findings show a novel mechanism that may contribute to the known role of folate in cancer prevention, and may lead to the use of PSMA inhibitors as novel chemopreventive agents for prostate cancer. Moreover, our model should prove useful for further dissecting pathways involved in prostate carcinogenesis and progression. [Cancer Res 2008;68(21):9070–7]

Florian Stelzle - One of the best experts on this subject based on the ideXlab platform.

  • qualitative Tissue Differentiation by analysing the intensity ratios of atomic emission lines using laser induced breakdown spectroscopy libs prospects for a feedback mechanism for surgical laser systems
    Journal of Biophotonics, 2015
    Co-Authors: Rajesh Kanawade, Katja Tangermanngerk, Werner Adler, Michael Schmidt, Fanuel Mahari, Florian Klampfl, Maximilian Rohde, Christian Knipfer, Florian Stelzle
    Abstract:

    The research work presented in this paper focuses on qualitative Tissue Differentiation by monitoring the intensity ratios of atomic emissions using ‘Laser Induced Breakdown Spectroscopy’ (LIBS) on the plasma plume created during laser Tissue ablation. The background of this study is to establish a real time feedback control mechanism for clinical laser surgery systems during the laser ablation process. Ex-vivo domestic pig Tissue samples (muscle, fat, nerve and skin) were used in this experiment. Atomic emission intensity ratios were analyzed to find a characteristic spectral line for each Tissue. The results showed characteristic elemental emission intensity ratios for the respective Tissues. The spectral lines and intensity ratios of these specific elements varied among the different Tissue types. The main goal of this study is to qualitatively and precisely identify different Tissue types for Tissue specific laser surgery. (© 2013 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim)

  • pilot study of laser induced breakdown spectroscopy for Tissue Differentiation by monitoring the plume created during laser surgery an approach on a feedback laser control mechanism
    Spectrochimica Acta Part B: Atomic Spectroscopy, 2013
    Co-Authors: Rajesh Kanawade, Katja Tangermanngerk, Maximilian Rohde, Christian Knipfer, Fanuel Mehari, M Schmidt, Florian Stelzle
    Abstract:

    Abstract This study focuses on Tissue Differentiation using ‘Laser Induced Breakdown Spectroscopy’ (LIBS) by monitoring the plasma plume created during laser surgery processes. This technique is aimed at controlling a laser surgery feedback system in real time. An Excimer laser (Ar-F 193 nm) was used for the ablation of Tissue samples. Fat, muscle, nerve and skin Tissue samples of bisected ex-vivo pig heads were prepared as test objects for the ablation procedure. A single fiber was used to collect emissions and deliver them to a spectrometer. The obtained LIBS spectra in the measured emissions were analyzed to determine each Tissue type according to their chemical composition. The elements found in the samples and their emission spectra were in agreement with those described in literature. The collected LIBS spectra were analyzed to differentiate the Tissues using statistical data analysis: Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA) and Receiver Operating Characteristics (ROC). The obtained preliminary results suggest a successful Differentiation of the target Tissues with high sensitivity and specificity. The main goal of this study was to qualitatively identify Tissue types during laser ablation, which will provide a real time feedback mechanism for clinical Laser surgery applications to significantly improve the accuracy and safety of laser surgery procedures.

  • diffuse reflectance spectroscopy for optical soft Tissue Differentiation as remote feedback control for Tissue specific laser surgery
    Lasers in Surgery and Medicine, 2010
    Co-Authors: Florian Stelzle, Katja Tangermanngerk, Werner Adler, Azhar Zam, Michael Schmidt, Alexandre Douplik, Emeka Nkenke
    Abstract:

    Background and Objective Laser surgery does not provide haptic feedback for operating layer-by-layer and thereby preserving vulnerable anatomical structures like nerve Tissue or blood vessels. Diffuse reflectance spectra can facilitate remote optical Tissue Differentiation. It is the aim of the study to use this technique on soft Tissue samples, to set a technological basis for a remote optical feedback system for Tissue-specific laser surgery. Materials and Methods Diffuse reflectance spectra (wavelength range: 350–650 nm) of ex vivo types of soft Tissue (a total of 10,800 spectra) of the midfacial region of domestic pigs were remotely measured under reduced environmental light conditions and analyzed in order to differentiate between skin, mucosa, muscle, subcutaneous fat, and nerve Tissue. We performed a principal components (PC) analysis (PCA) to reduce the number of variables. Linear discriminant analysis (LDA) was utilized for classification. For the Tissue Differentiation, we calculated the specificity and sensitivity by receiver operating characteristic (ROC) analysis and the area under curve (AUC). Results Six PCs were found to be adequate for Tissue Differentiation with diffuse reflectance spectra using LDA. All of the types of soft Tissue could be differentiated with high specificity and sensitivity. Only the Tissue pairs nervous Tissue/fatty Tissue and nervous Tissue/mucosa showed a decline of Differentiation due to bio-structural similarity. However, both of these Tissue pairs could still be differentiated with a specificity and sensitivity of more than 90%. Conclusions Analyzing diffuse reflectance spectroscopy with PCA and LDA allows for remote Differentiation of biological Tissue. Considering the limitations of the ex vivo conditions, the obtained results are promising and set a basis for the further development of a feedback system for Tissue-specific laser surgery. Lasers Surg. Med. 42:319–325, 2010. © 2010 Wiley-Liss, Inc.

P J Prendergast - One of the best experts on this subject based on the ideXlab platform.

  • simulation of angiogenesis and cell Differentiation in a cap scaffold subjected to compressive strains using a lattice modeling approach
    Biomaterials, 2010
    Co-Authors: C Sandino, P J Prendergast, Sara Checa, Damien Lacroix
    Abstract:

    Mechanical stimuli are one of the factors that influence Tissue Differentiation. In the development of biomaterials for bone Tissue engineering, mechanical stimuli and formation of a vascular network that transport oxygen to cells within the pores of the scaffolds are essential. Angiogenesis and cell Differentiation have been simulated in scaffolds of regular porosity; however, the dynamics of Differentiation can be different when the porosity is not uniform. The objective of this study was to investigate the effect of the mechanical stimuli and the capillary network formation on cell Differentiation within a scaffold of irregular morphology. A porous scaffold of calcium phosphate based glass was used. The pores and the solid phase were discretized using micro computed tomography images. Cell activity was simulated within the interconnected pore domain of the scaffold using a lattice modeling approach. Compressive strains of 0.5 and 1% of total deformation were applied and two cases of mesenchymal stem cells initialization (in vitro seeding and in vivo) were simulated. Similar capillary networks were formed independently of the cell initialization mode and the magnitude of the mechanical strain applied. Most of vessels grew in the pores at the periphery of the scaffolds and were blocked by the walls of the scaffold. When 0.5% of strain was applied, 70% of the pore volume was affected by mechano-regulatory stimuli corresponding to bone formation; however, because of the lack of oxygen, only 40% of the volume was filled with osteoblasts. 40% of volume was filled with chondrocytes and 3% with fibroblasts. When the mechanical strain was increased to 1%, 11% of the pore volume was filled with osteoblasts, 59% with chondrocytes, and 8% with fibroblasts. This study has shown the dynamics of the correlation between mechanical load, angiogenesis and Tissue Differentiation within a scaffold with irregular morphology.

  • simulation of Tissue Differentiation in a scaffold as a function of porosity young s modulus and dissolution rate application of mechanobiological models in Tissue engineering
    Biomaterials, 2007
    Co-Authors: Damien P Byrne, Daniel J. Kelly, Damien Lacroix, Josep A Planell, P J Prendergast
    Abstract:

    Abstract Numerous experimental studies have attempted to determine the optimal properties for a scaffold for use in bone Tissue engineering but, as yet, no computational or theoretical approach has been developed that suggests how best to combine the various design parameters, e.g. scaffold porosity, Young's modulus, and dissolution rate. Previous research has shown that bone regeneration during fracture healing and osteochondral defect repair can be simulated using mechanoregulation algorithms based on computing strain and/or fluid flow in the regenerating Tissue. In this paper a fully three-dimensional approach is used for computer simulation of Tissue Differentiation and bone regeneration in a regular scaffold as a function of porosity, Young's modulus, and dissolution rate—and this is done under both low and high loading conditions. The mechanoregulation algorithm employed determines Tissue Differentiation both in terms of the prevailing biophysical stimulus and number of precursor cells, where cell number is computed based on a three-dimensional random-walk approach. The simulations predict that all three design variables have a critical effect on the amount of bone regenerated, but not in an intuitive way: in a low load environment, a higher porosity and higher stiffness but a medium dissolution rate gives the greatest amount of bone whereas in a high load environment the dissolution rate should be lower otherwise the scaffold will collapse—at lower initial porosities however, higher dissolution rates can be sustained. Besides showing that scaffolds may be optimised to suit the site-specific loading requirements, the results open up a new approach for computational simulations in Tissue engineering.

  • a mechano regulation model for Tissue Differentiation during fracture healing analysis of gap size and loading
    Journal of Biomechanics, 2002
    Co-Authors: Damien Lacroix, P J Prendergast
    Abstract:

    Bone has a capability to repair itself when it is fractured. Repair involves the generation of intermediate Tissues, such as fibrous connective Tissue, cartilage and woven bone, before final bone healing can occur. The intermediate Tissues serve to stabilise the mechanical environment and provide a scaffold for Differentiation of new Tissues. The repair process is fundamentally affected by mechanical loading and by the geometric configuration of the fracture fragments. Biomechanical analyses of fracture healing have previously computed the stress distribution within the callus and identified the components of the stress tensor favouring or inhibiting Differentiation of particular Tissue phenotypes. In this paper, a biphasic poroelastic finite element model of a fracture callus is used to simulate the time-course of Tissue Differentiation during fracture healing. The simulation begins with granulation Tissue (post-inflammation phase) and finishes with bone resorption. The biomechanical regulatory model assumes that Tissue Differentiation is controlled by a combination of shear strain and fluid flow acting within the Tissue. High shear strain and fluid flows are assumed to deform the precoursor cells stimulating formation of fibrous connective Tissue, lower levels stimulate formation of cartilage, and lower again allows ossification. This mechano-regulatory scheme was tested by simulating healing in fractures with different gap sizes and loading magnitudes. The appearance and disappearance of the various Tissues found in a callus was similar to histological observation. The effect of gap size and loading magnitude on the rate of reduction of the interfragmentary strain was sufficiently close to confirm the hypothesis that Tissue Differentiation phenomena could be governed by the proposed mechano-regulation model.

  • biomechanical model to simulate Tissue Differentiation and bone regeneration application to fracture healing
    Medical & Biological Engineering & Computing, 2002
    Co-Authors: Damien Lacroix, P J Prendergast, David Marsh
    Abstract:

    Bone regeneration is a common biological process occurring, for example, during fracture healing or osseo-integration of prostheses. Computer simulation of bone regeneration is difficult to carry out because it is a complex sequence of cell-mediated processes regulated by mechanobiological stimuli. An algorithm to predict the time-course of intramembranous and endochondral ossification has been developed. The algorithm assumes that there are precursor cells in the undifferentiated Tissue and that these cells differentiate into either fibroblasts (to form fibrous connective Tissue), chondrocytes (to form cartilaginous Tissue) or osteoblasts (to form bone), based on a combination of biophysical stimuli derived from strain in the collagenous matrix and flow of the interstitial fluid. Both these stimuli are known to deform the precursor cells, and the authors hypothesise that this causes activation of cell Differentiation pathways. The observation that precursor cells take time to spread throughout the fracture callus has been included in the algorithm. The algorithm was tested in an investigation of the fracture healing of a long bone using an axisymmetric finite element model. The spatio-temporal sequence of Tissue phenotypes that appear in the course of fracture healing was successfully simulated. Furthermore, the origin of the precursor cells (either surrounding muscle, bone marrow or periosteum) was predicted to have a fundamental effect on the healing pattern and on the rate of reduction of the interfragmentary strain (IFS). The initial IFS=0.15 drops to 0.01 within seven iterations if cells originated from the surrounding soft Tissue, but took more than 50% longer if cells originated in the inner cambium layer of the periosteum, and four times longer if precursor cells originated from the bone marrow only.

  • a biomechanical regulatory model for periprosthetic fibrous Tissue Differentiation
    Journal of Materials Science: Materials in Medicine, 1997
    Co-Authors: R Huiskes, W D Van Driel, P J Prendergast, K Soballe
    Abstract:

    Loosening of implants in bone is commonly associated with a development of fibrous interface Tissues, due to interface gaps and a lack of mechanical stability. It has been postulated that the Differentiation of these Tissues to fibrocartilage or bone is governed by mechanical stimuli. The objective of our research is to unravel these relationships to the extent that the question whether an implant will loosen can be answered from initial conditions determined by implant and interface morphology, and functional loads. In this project we studied the hypothesis that distortional strain and interstitial fluid flow are the mechanical stimuli governing Tissue Differentiation. For that purpose, a biomechanical regulatory model was developed and used in association with a finite element code to simulate animal experiments with implants moving in bone. The similarities between the implant incorporation process found in the experiment and its simulation with the computer model demonstrate that our hypothesis is viable from a regulatory point of view.

Veronica Yao - One of the best experts on this subject based on the ideXlab platform.

  • moderate expression of prostate specific membrane antigen a Tissue Differentiation antigen and folate hydrolase facilitates prostate carcinogenesis
    Cancer Research, 2008
    Co-Authors: Veronica Yao, Anil V Parwani, Christoph Maier, Warren D W Heston, Dean J Bacich
    Abstract:

    Increased expression of PSMA, a Differentiation antigen with folate hydrolase activity, is an independent marker of prostate cancer progression. Mice expressing moderate levels of human PSMA in their prostate develop PIN-like lesions by 9 months. The aim of this study was to determine whether PSMA is involved in prostate carcinogenesis and progression and, if so, the possible mechanism by which PSMA may exert its effects. Using prostates from PSMA-transgenic mice, we developed a Tissue recombinant model that exhibits small atypical glands with features of adenocarcinoma. This was not observed in Tissue recombinants that were composed of prostate Tissues from the wild-type siblings. Cells from PSMA-transgenic Tissue recombinants have the ability to form colonies in semisolid agar. PSMA may facilitate this phenotype by increasing the invasive ability of cells. Ectopic PSMA expression on PC-3 cells increased the invasive capacity of cells in in vitro invasion assays, which could be competed out by folic acid. These results suggest PSMA facilitates the development of prostate cancer, and the invasive ability of these cells may be modulated by folate levels. These findings show a novel mechanism that may contribute to the known role of folate in cancer prevention, and may lead to the use of PSMA inhibitors as novel chemopreventive agents for prostate cancer. Moreover, our model should prove useful for further dissecting pathways involved in prostate carcinogenesis and progression.

  • moderate expression of prostate specific membrane antigen a Tissue Differentiation antigen and folate hydrolase facilitates prostate carcinogenesis
    Cancer Research, 2008
    Co-Authors: Veronica Yao, Anil V Parwani, Christoph Maier, Warren D W Heston, Dean J Bacich
    Abstract:

    Increased expression of PSMA, a Differentiation antigen with folate hydrolase activity, is an independent marker of prostate cancer progression. Mice expressing moderate levels of human PSMA in their prostate develop PIN-like lesions by 9 months. The aim of this study was to determine whether PSMA is involved in prostate carcinogenesis and progression and, if so, the possible mechanism by which PSMA may exert its effects. Using prostates from PSMA-transgenic mice, we developed a Tissue recombinant model that exhibits small atypical glands with features of adenocarcinoma. This was not observed in Tissue recombinants that were composed of prostate Tissues from the wild-type siblings. Cells from PSMA-transgenic Tissue recombinants have the ability to form colonies in semisolid agar. PSMA may facilitate this phenotype by increasing the invasive ability of cells. Ectopic PSMA expression on PC-3 cells increased the invasive capacity of cells in in vitro invasion assays, which could be competed out by folic acid. These results suggest PSMA facilitates the development of prostate cancer, and the invasive ability of these cells may be modulated by folate levels. These findings show a novel mechanism that may contribute to the known role of folate in cancer prevention, and may lead to the use of PSMA inhibitors as novel chemopreventive agents for prostate cancer. Moreover, our model should prove useful for further dissecting pathways involved in prostate carcinogenesis and progression. [Cancer Res 2008;68(21):9070–7]

Seunghwan Chang - One of the best experts on this subject based on the ideXlab platform.

  • mechano regulation theory based finite element analysis on the effects of driving strain history on cellular Differentiation
    International Journal of Precision Engineering and Manufacturing, 2015
    Co-Authors: Seunghwan Chang
    Abstract:

    The aim of this study was to determine the appropriate driving strain history of a dynamic cell culture device for inducing accelerated cell Differentiation. Silicone rubber film is an electroactive polymer and was used as a flexible cell stimulator to transfer mechanical strains to developing cells. Mechano-regulation theory with a deviatoric strain was used to estimate Tissue Differentiation under strain conditions during iterative calculations by means of finite element analysis. Various driving strain histories comprising 4%, 5%, and 6% strains were introduced to determine the correlation between the strain history and the development of cell phenotypes. The simulation results revealed that driving strain conditions mainly comprising low levels of strain (4%) provided appropriate conditions for differentiating mesenchymal cells into osteoblasts.

  • the finite element analysis for endochondral ossification process of a fractured tibia applied with a composite im rod based on a mechano regulation theory using a deviatoric strain
    Composites Part B-engineering, 2014
    Co-Authors: Hassan Mehboob, Hojoong Jung, Seunghwan Chang
    Abstract:

    Abstract The bone healing process of fractured tibias applied with various composite IM rods, respectively, was analyzed using finite element analysis. Based on a mechano-regulation theory with a deviatoric strain as a mechanical stimulation the process of Tissue Differentiation was simulated by a user’s subroutine programmed by a Python code for an iterative calculation. Several representative composite IM rods (fabric composites made of a carbon/epoxy and a glass/polypropylene) were investigated to find the rod modulus appropriate for healing bone fractures. It was found that the initial loading condition was the most sensitive factor of healing performance and that the flexible composite IM rod (WSN3k [±45]nT) was able to accelerate Tissue Differentiation under a reasonable initial loading condition (3 point gait after surgery), resulting in early bone union.

  • the simulation of bone healing process of fractured tibia applied with composite bone plates according to the diaphyseal oblique angle and plate modulus
    Composites Part B-engineering, 2013
    Co-Authors: Daesung Son, Seunghwan Chang
    Abstract:

    Abstract This paper presents the simulation of the bone healing process of a fractured tibia with oblique angles according to plate modulus and initial loading condition by FE analysis. To simulate Tissue Differentiation and the pathway of development of the curing cells during the healing process, a mechano-regulation theory on deviatoric strain is introduced. For the iterative calculation to determine cell phenotype during the healing period, a user subroutine was programmed by Python code. The analysis result revealed that the healing efficiency was strongly affected by the initial loading condition and the coupling of the plate’s modulus with the oblique angle. By FE analysis, the most appropriate plate modulus for each initial load condition and oblique angle was suggested.

  • the simulation of Tissue Differentiation at a fracture gap using a mechano regulation theory dealing with deviatoric strains in the presence of a composite bone plate
    Composites Part B-engineering, 2012
    Co-Authors: Hyunjun Kim, Seunghwan Chang, Hojoong Jung
    Abstract:

    Abstract The endochondral ossification process of fractured long bones was simulated using a three-dimensional finite element model when various composite bone plates were applied to the fracture site. To simulate time-varying cell phenotypes and the corresponding deviatoric strains in the calluses, a user’s subroutine was programmed for iterative calculations. Three representative initial loading conditions were investigated to find a relationship between the initial loading condition and Tissue Differentiation. Through finite element analysis, the trends in Tissue Differentiation and healing efficiency in the calluses were evaluated according to the plate modulus and loading conditions; further, the most appropriate plate modulus under each initial loading condition was suggested.