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Results 251 - 300 of 1933
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Fletcher Sarah J - - 2010
Polarised vesicle trafficking has been suggested to regulate cell migration. Understanding how this takes place has been complicated by the use of disparate assays and cellular models. Although polarised trafficking does occur in cell motility it is not clear which pathways are involved. We propose a model for migrating cells ...
Chen Wen Li Kelly - - 2010
Cell-substrate interactions are multifaceted, involving the integration of various physical and biochemical signals. The interactions among these microenvironmental factors cannot be facilely elucidated and quantified by conventional experimentation, and necessitate multifactorial strategies. Here we describe an approach that integrates statistical design and analysis of experiments with automated microscopy to systematically ...
Jeon Junhwan - - 2010
We have developed an off-lattice hybrid discrete-continuum (OLHDC) model of tumor growth and invasion. The continuum part of the OLHDC model describes microenvironmental components such as matrix-degrading enzymes, nutrients or oxygen, and extracellular matrix (ECM) concentrations, whereas the discrete portion represents individual cell behavior such as cell cycle, cell-cell, and ...
Champion Patrick D - - 2010
Monoclonal B-cell lymphocytosis (MBL) is defined by the presence of monoclonal B-cells in peripheral blood in the absence of hematologic disease. MBL is detected by flow cytometry with increasing frequency as the number of B-cells acquired increases. Computer simulations in R language were used to examine the impact of increasing ...
El-Manzalawy Yasser - - 2010
Identification of epitopes that invoke strong responses from B-cells is one of the key steps in designing effective vaccines against pathogens. Because experimental determination of epitopes is expensive in terms of cost, time, and effort involved, there is an urgent need for computational methods for reliable identification of B-cell epitopes. ...
Bowers Jeffrey S - - 2010
Replies to the comments by Plaut and McClelland and Quian Quiroga and Kreiman on the authors original article both challenged my characterization of localist and distributed representations. They also challenged the biological plausibility of grandmother cells on conceptual and empirical grounds. This reply addresses these issues in turn. The premise ...
Van Liedekerke P - - 2010
This paper is concerned with addressing how plant tissue mechanics is related to the micromechanics of cells. To this end, we propose a mesh-free particle method to simulate the mechanics of both individual plant cells (parenchyma) and cell aggregates in response to external stresses. The model considers two important features ...
Bogle Gib - - 2010
Activation of T cells by antigen-presenting cells (APCs) in lymph nodes (LNs) is a key initiating event in many immune responses. Our understanding of this process has been both improved and complicated in recent years by evidence from techniques such as intravital microscopy that has revealed new levels of dynamism ...
Janowski Sebastian - - 2010
The understanding of the molecular mechanism of cell-to-cell communication is fundamental for system biology. Up to now, the main objectives of bioinformatics have been reconstruction, modeling and analysis of metabolic, regulatory and signaling processes, based on data generated from high-throughput technologies. Cell-to-cell communication or quorum sensing (QS), the use of ...
De Wever Olivier - - 2010
Tumor invasion is the outcome of a complex interplay between cancer cells and the stromal environment. Considering the contribution of the stromal environment, we developed a membrane-free single-cell and spheroid based complementary model to study cancer invasion through native collagen type-I matrices. Cell morphology is preserved during the assays allowing ...
Tayi Venkata S - - 2010
A quantitative understanding of the process of retrovirus-mediated gene transfer into mammalian cells should assist the design and optimization of transduction protocols. We present a mathematical model of the process that incorporates the essential rate-limiting transduction steps including diffusion, convection and decay of viral vectors, their binding at the cell ...
Koziol Uriel - - 2010
In free-living flatworms somatic differentiated cells do not divide, and a separate population of stem cells (called neoblasts) is responsible for cell proliferation and renewal. In cestodes, there is evidence that similar mechanisms of cell renewal exist. In this work, we have characterized proliferative cells during the development of the ...
Janowski Miroslaw - - 2010
The last decade has been marked by a growing interest in an employment of intravenous cell delivery for treatment of neurological disorders. Numerous preclinical experimental studies have reported functional benefits, and have recently been followed by clinical trials. Some early clinical studies have indicated only modest positive effects, suggesting that ...
Kaivosoja Emilia - - 2010
Micro-textured biomaterials might enhance cytocompatibility of silicon-based micro-electro-mechanical system (bio-MEMS) dummies. Photolithography-physical vapour deposition was used to produce diamond-like carbon (DLC) or Ti squares and circles on silicon, and also their inverse replicas; then DLC and Ti were compared for their guiding potential, using a SaOS-2 cell model. Scanning electron ...
Han Ju - - 2010
Cell membrane proteins play an important role in tissue architecture and cell-cell communication. We hypothesize that segmentation and multidimensional characterization of the distribution of cell membrane proteins, on a cell-by-cell basis, enable improved classification of treatment groups and identify important characteristics that can otherwise be hidden. We have developed a ...
Rejniak Katarzyna A - - 2010
Most tumors arise from epithelial tissues, such as mammary glands and lobules, and their initiation is associated with the disruption of a finely defined epithelial architecture. Progression from intraductal to invasive tumors is related to genetic mutations that occur at a subcellular level but manifest themselves as functional and morphological ...
Jamali Yousef - - 2010
Understanding the biomechanical properties and the effect of biomechanical force on epithelial cells is key to understanding how epithelial cells form uniquely shaped structures in two or three-dimensional space. Nevertheless, with the limitations and challenges posed by biological experiments at this scale, it becomes advantageous to use mathematical and 'in ...
Thalhauser Craig J - - 2010
We study the selection dynamics in a heterogeneous spatial colony of cells. We use two spatial generalizations of the Moran process, which include cell divisions, death and migration. In the first model, migration is included explicitly as movement to a proximal location. In the second, migration is implicit, through the ...
Cselenyák Attila - - 2010
Bone marrow derived mesenchymal stem cells (MSCs) are promising candidates for cell based therapies in myocardial infarction. However, the exact underlying cellular mechanisms are still not fully understood. Our aim was to explore the possible role of direct cell-to-cell interaction between ischemic H9c2 cardiomyoblasts and normal MSCs. Using an in ...
Naldi Aurélien - - 2010
Alternative cell differentiation pathways are believed to arise from the concerted action of signalling pathways and transcriptional regulatory networks. However, the prediction of mammalian cell differentiation from the knowledge of the presence of specific signals and transcriptional factors is still a daunting challenge. In this respect, the vertebrate hematopoietic system, ...
Van Haastert Peter J M - - 2010
Cell migration in the absence of external cues is well described by a correlated random walk. Most single cells move by extending protrusions called pseudopodia. To deduce how cells walk, we have analyzed the formation of pseudopodia by Dictyostelium cells. We have observed that the formation of pseudopodia is highly ...
Ylä-Outinen Laura - - 2010
At present, most of the neurotoxicological analyses are based on in vitro and in vivo models utilizing animal cells or animal models. In addition, the used in vitro models are mostly based on molecular biological end-point analyses. Thus, for neurotoxicological screening, human cell-based analysis platforms in which the functional neuronal ...
Larson David E DE The Genome Center at Washington University, St. Louis, Missouri, United States of - - 2010
We present a computer simulation and associated experimental validation of assembly of glial-like support cells into the interweaving hexagonal lattice that spans the Drosophila pupal eye. This process of cell movements organizes the ommatidial array into a functional pattern. Unlike earlier simulations that focused on the arrangements of cells within ...
De Vylder Jonas J Institute for the Promotion of Innovation by Science and Technology in Flanders (IWT), Belgium. - - 2010
The dynamics of genome regions are associated to the functional or dysfunctional behaviour of the human cell. In order to study these dynamics it is necessary to remove perturbations coming from movement and deformation of the nucleus, i.e. the container holding the genome. In literature models have been proposed to ...
Huclova Sonja S Electromagnetic Fields and Microwave Electronics Laboratory (IFH), Swiss Federal Institute of Technology (ETH Zurich), Gloriastrasse 35, 8092, - - 2010
In the past, mainly analytical mixing formulas were used for modeling of dielectric properties of biological cells. General drawbacks of such formulas are the restriction to simple shapes and small cellular volume fractions. Assuming cell suspensions or tissues being quasi-periodic the problem size can be reduced to a cubic unit ...
Shapiro Irving M - - 2010
This editorial addresses the debate concerning the origin of adult nucleus pulposus cells in the light of profiling studies by Minogue and colleagues. In their report of several marker genes that distinguish nucleus pulposus cells from other related cell types, the authors provide novel insights into the notochordal nature of ...
Carlsson Anders E AE Department of Physics, Washington University, St. Louis, Missouri 63130, USA. - - 2010
The dynamic nature of actin in cells manifests itself constantly. Polymerization near the cell edge is balanced by depolymerization in the interior, externally induced actin polymerization is followed by depolymerization, and spontaneous oscillations of actin at the cell periphery are frequently seen. I discuss how mathematical modeling relates quantitative measures ...
Hyrien Ollivier O Department of Biostatistics & Computational Biology, University of Rochester Medical Center, Rochester, NY 14642, USA. - - 2010
Over the past decade, flow cytometric CFSE-labeling experiments have gained considerable popularity among experimentalists, especially immunologists and hematologists, for studying the processes of cell proliferation and cell death. Several mathematical models have been presented in the literature to describe cell kinetics during these experiments. We propose a multi-type age-dependent branching ...
Belete Hewan A - - 2010
Cell wounding, that is a loss of plasma membrane integrity, is a common everyday occurrence in load bearing organs such as muscle, skin, and bone. In general, these injuries trigger adaptive responses to either restore homeostasis or to protect the cells from further damage. The ability to restore plasma membrane ...
Cookson Natalie A NA Department of Bioengineering, BioCircuits Institute, Molecular Biology Section, Division of Biology, University of California, San Diego, La Jolla, CA 92093, - - 2010
Computational modeling of biological systems has become an effective tool for analyzing cellular behavior and for elucidating key properties of the intricate networks that underlie experimental observations. While most modeling techniques rely heavily on the concentrations of intracellular molecules, little attention has been paid to tracking and simulating the significant ...
Michelin S?bastien - - 2010
Swimming microorganisms such as bacteria or spermatozoa are typically found in dense suspensions, and exhibit collective modes of locomotion qualitatively different from that displayed by isolated cells. In the dilute limit where fluid-mediated interactions can be treated rigorously, the long-time hydrodynamics of a collection of cells result from interactions with ...
Hutson M Shane - - 2009
Laser microsurgery and finite element modeling are used to determine the cell-level mechanics of the amnioserosa-a morphogenetically crucial epithelium on the dorsal surface of fruit fly embryos (Drosophila melanogaster). In the experiments, a tightly focused laser ablates a subcellular hole (1 microm in diameter) that passes clean through the epithelium. ...
Kim Peter S PS Department of Mathematics, University of Utah, Salt Lake City, UT 84112-0090, - - 2010
The currently accepted paradigm for the primary T cell response is that effector T cells commit to autonomous developmental programs. This concept is based on several experiments that have demonstrated that the dynamics of a T cell response is largely determined shortly after antigen exposure and that T cell dynamics ...
Abbas Lamia - - 2009
The paper presents the classical age-dependent approach of the morphogenesis in the framework of the von Foerster equation, in which we introduce a new constraint and study a new feature: (i) the new constraint concerns cell proliferation along the contour lines of the cell density, depending on the local curvature ...
Schamberg S - - 2010
Planar cell polarity (PCP) occurs in the epithelia of many animals and can lead to the alignment of hairs, bristles, and feathers. Here, we present two approaches to modelling this phenomenon. The aim is to discover the basic mechanisms that drive PCP, while keeping the models mathematically tractable. We present ...
Hjelm Brooke E - - 2010
We have developed an in vitro human vaginal epithelial cell (EC) model using the innovative rotating wall vessel (RWV) bioreactor technology that recapitulates in vivo structural and functional properties, including a stratified squamous epithelium with microvilli, tight junctions, microfolds, and mucus. This three-dimensional (3-D) vaginal model provides a platform for ...
Maler Adrian - - 2010
Mechanistic dynamic cell population models for the tumour control probability (TCP) to date have used a simplistic representation of the cell cycle: either an exponential cell-cycle time distribution (Zaider & Minerbo, 2000, Tumour control probability: a formulation applicable to any temporal protocol of dose delivery. Phys. Med. Biol., 45, 279-293) ...
Schneider M R - - 2010
Embryonic stem cells (ESCs) are permanent cell lines that can be maintained in a pluripotent, undifferentiated state. Appropriate environmental stimuli can cause them to differentiate into cell types of all three germ layers both in vitro and in vivo. Embryonic stem cells bear many opportunities for clinical applications in tissue ...
Geris Liesbet - - 2010
In this study, a cell based lattice free modelling framework is proposed to study cell aggregate behaviour in bone tissue engineering applications. The model encompasses cell-to-cell and cell-environment interactions such as adhesion, repulsion and drag forces. Oxygen, nutrients, waste products, growth factors and inhibitors are explicitly represented in the model ...
Johnson Jed - - 2009
Malignant gliomas are the most common tumors originating within the central nervous system and account for over 15,000 deaths annually in the United States. The median survival for glioblastoma, the most common and aggressive of these tumors, is only 14 months. Therapeutic strategies targeting glioma cells migrating away from the ...
Friedl Peter - - 2010
Cell migration underlies tissue formation, maintenance, and regeneration as well as pathological conditions such as cancer invasion. Structural and molecular determinants of both tissue environment and cell behavior define whether cells migrate individually (through amoeboid or mesenchymal modes) or collectively. Using a multiparameter tuning model, we describe how dimension, density, ...
Martín Osmel - - 2009
Oscillating biochemical reactions are common in cell dynamics and could be closely related to the emergence of the life phenomenon itself. In this work, we study the dynamical features of some classical chemical or biochemical oscillators where the effect of cell volume changes is explicitly considered. Such analysis enables us ...
Lee Jack Y - - 2009
The active movement of cells from subendothelial compartments into the bloodstream (intravasation) has been recognized for several decades by histologic and physiologic studies, yet the molecular effectors of this process are relatively uncharacterized. For extravasation, studies based predominantly on static transwell assays support a general model, whereby transendothelial migration (TEM) ...
Welsh Marleen M Department of Medicine, University of Chicago, Chicago, Illinois 60637, - - 2009
Quantitative variation in response to drugs in human populations is multifactorial; genetic factors probably contribute to a significant extent. Identification of the genetic contribution to drug response typically comes from clinical observations and use of classic genetic tools. These clinical studies are limited by our inability to control environmental factors ...
Chauviere A - - 2010
Cell migration involves different mechanisms in different cell types and tissue environments. Changes in migratory behaviour have been observed experimentally and associated with phenotypic switching in various situations, such as the migration-proliferation dichotomy of glioma cells, the epithelial-mesenchymal transition or the mesenchymal-amoeboid transition of fibrosarcoma cells in the extracellular matrix ...
Bogle Gib - - 2010
Recent intravital microscopy experiments have revealed the complex behavior of T cells within lymph nodes. Modeling T-cell responses in lymph nodes now requires integration of cell trafficking and motility with the molecular processes involved in T-cell activation. We describe an agent-based model that allows such integration, in which T cells ...
Bock Andreas - - 2009
An assay for measuring the number of adherent cells on microcarriers that is independent from dilution errors in sample preparation was used to investigate attachment dynamics and cell growth. It could be shown that the recovery of seeded cells is a function of the specific rates of cell attachment and ...
Diplas Andreas I - - 2009
Loss of imprinting (LOI) is the reactivation of the silenced allele of an imprinted gene, leading to perturbation of monoallelic expression. We tested the hypothesis that LOI of PLAGL1, a representative maternally imprinted gene, occurs through an all-or-none process leading to a mixture of fully imprinted and nonimprinted cells. Herein ...
Roach Kenneth L KL Center for Engineering in Medicine, BioMEMS Resource Center, Massachusetts General Hospital, Harvard Medical School, Shriners Hospital for Children, Boston, MA, - - 2009
Advances in systems biology and bioinformatics have highlighted that no cell population is truly uniform and that stochastic behavior is an inherent property of many biological systems. As a result, bulk measurements can be misleading even when particular care has been taken to isolate a single cell type, and measurements ...
Dailey H L - - 2010
The reopening of fluid-occluded pulmonary airways generates microbubble flows which impart complex hydrodynamic stresses to the epithelial cells lining airway walls. In this study we used boundary element solutions and finite element techniques to investigate how cell rheology influences the deformation and injury of cells during microbubble flows. An optimized ...
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