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Results 301 - 350 of 1912
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Angerer Wolfgang P - - 2010
We discuss the evaluation of Luria-Delbrück fluctuation experiments under Bellman-Harris models of cell proliferation. It is shown that under certain very natural assumptions concerning the life-time distributions and the offspring distributions of mutant and non-mutant cells, the suitably normed and centered number of mutants contained in a large culture of ...
Chapin Robert E - - 2009
The National Research Council's (NRC) toxicity testing vision lays out a bold future for our field. It depends heavily on computational algorithms based on the latest knowledge of cellular biochemistry and protein interaction pathways, exposing human cells to novel compounds in vitro, and being able to understand the changes seen. ...
Augusto Elisabeth F P - - 2010
Studies of a bioprocess optimization and monitoring for protein synthesis in animal cells face a challenge on how to express in quantitative terms the system performance. It is possible to have a panel of calculated variables that fits more or less appropriately the intended goal. Each mathematical expression approach translates ...
McGarry J P - - 2009
A substantial body of work has been reported in which the mechanical properties of adherent cells were characterized using compression testing in tandem with computational modeling. However, a number of important issues remain to be addressed. In the current study, using computational analyses, the effect of cell compressibility on the ...
Lin Chih-Min CM Department of Pathology, University of Southern California, Los Angeles, CA 90033, - - 2009
A key issue in stem cell biology is the differentiation of homogeneous stem cells towards different fates which are also organized into desired configurations. Little is known about the mechanisms underlying the process of periodic patterning. Feather explants offer a fundamental and testable model in which multi-potential cells are organized ...
Lee Min Woo - - 2009
In this article, we propose an individual-based and stochastic modeling approach that is capable of describing the bacterial cell population dynamics during a batch culture. All stochastic nature inherent in intracellular molecular level reactions and cell division processes were considered in a single model framework by embedding a sub-model describing ...
Harisi Revekka - - 2009
For the control of tumor metastasis it is important to identify chemical compounds with antimigratory potency. Agents acting against single cell and cluster type migration are necessary for successful antimetastatic therapy. In the present study, the migration of HT-1080 fibrosarcoma cells and OSCORT osteosarcoma cells was compared in a Boyden ...
Cheng Gang - - 2009
To provide theoretical guidance for the design and in vitro cultivation of bioartificial tissues, we have developed a multiscale computational model that can describe the complex interplay between cell population and mass transport dynamics that governs the growth of tissues in three-dimensional scaffolds. The model has three components: a transient ...
Zhang Tongli - - 2009
Multicellular organisms shape development and remove aberrant cells by programmed cell death ("apoptosis"). Because defective cell death (too little or too much) is implicated in various diseases (like cancer and autoimmunity), understanding how apoptosis is regulated is an important goal of molecular cell biologists. To this end, we propose a ...
Starosta Matthew S - - 2009
The FDTD method was used to simulate focused Gaussian beam propagation through multiple inhomogeneous biological cells. To our knowledge this is the first three dimensional computational investigation of a focused beam interacting with multiple biological cells using FDTD. A parametric study was performed whereby three simulated cells were varied by ...
Wood Levi Benjamin - - 2009
This paper presents a framework for controlling the development of a vascular system in an in vitro angiogenesis process. Based on online measurement of cell growth and a stochastic cell population model, a closed-loop control system is developed for regulating the process of cell migration and vascular system development. Angiogenesis ...
Fozard J A - - 2010
This work examines a 1D individual-based model (IBM) for a system of tightly adherent cells, such as an epithelial monolayer. Each cell occupies a bounded region, defined by the location of its endpoints, has both elastic and viscous mechanical properties and is subject to drag generated by adhesion to the ...
Ron Amit - - 2009
The dielectric dispersion characteristics of cellular suspensions are fundamentally determined based on the analogy to composite dielectric materials when periodically and discrete arrangement of cells is assumed. However, under native physiological conditions, when flocculation and clamping events usually occur, those assumptions are usually not valid. In the framework of this ...
Foster David V - - 2009
Multipotent stem or progenitor cells undergo a sequential series of binary fate decisions, which ultimately generate the diversity of differentiated cells. Efforts to understand cell fate control have focused on simple gene regulatory circuits that predict the presence of multiple stable states, bifurcations and switch-like transitions. However, existing gene network ...
Kim Yangjin - - 2009
Glioblastoma is the most common and the most aggressive type of brain cancer. The median survival time from the time of diagnosis is approximately one year. Invasion of glioma cells from the core tumor into the surrounding brain tissue is a major reason for treatment failure: these migrating cells are ...
Jaeger Stefan - - 2009
The emergence of new microscopy techniques in combination with the increasing resource of bioimaging data has given fresh impetus to utilizing image processing methods for studying biological processes. Cell tracking studies in particular, which are important for a wide range of biological processes such as embryonic development or the immune ...
Su Jing - - 2009
Increasingly, combinatorial libraries are used to screen large numbers of complex chemically- and physically-patterned polymers against cell response. There is a strong need to extract meaningful relationships between cell function and material surface features from these experiments. A novel high-throughput cell-material screening strategy, based upon local cell-feature analysis (LCFA) was ...
Garbuzova-Davis Svitlana - - 2009
Sanfilippo syndrome type B (MPS III B) is caused by a deficiency of alpha-N-acetylglucosaminidase enzyme (Naglu), leading to accumulation of heparan sulfate (HS), a glycosaminoglycan (GAG), within lysosomes and to eventual progressive cerebral and systemic multiple organ abnormalities. Treatment of MPS patients is mainly supportive and enzyme replacement cell therapy ...
Seet Katrina Y T - - 2009
The cell nucleus is the dominant optical scatterer in the cell. Neoplastic cells are characterized by cell nucleus polymorphism and polychromism-i.e., the nuclei exhibits an increase in the distribution of both size and refractive index. The relative size parameter, and its distribution, is proportional to the product of the nucleus ...
Anetzberger Claudia - - 2009
Quorum sensing (QS) refers to the ability of bacterial populations to read out the local environment for cell density and to collectively activate gene expression. Vibrio harveyi, one of the best characterized model organisms in QS, was used to address the question how single cells behave within a QS-activated community ...
Surovtsev Ivan V - - 2009
Self-replication is an essential attribute of life but the molecular-level mechanisms involved are not well understood. Cellular self-replication requires not only duplicating all cellular components and doubling volume and membrane area, but also replicating cellular geometry. A whole-cell modeling framework is presented in which an assumed reaction network determines both ...
Li Hui - - 2009
We have already established human xenographic models for the effect of lysophosphatidic acid (LPA) on tumor metastasis in vivo. The purpose of this work is to establish a preclinical LPA effect model in immunocompetent mice. We first characterized the mouse epithelial ovarian cancer (EOC) cell line ID8 for its responsiveness ...
Demekhin Evgeny - - 2009
The nematode sperm cell crawls by recycling major sperm protein (MSP) from dimers into subfilaments, filaments, and filament complexes, as a result of thermal writhing in the presence of hydrophobic patches. Polymerization near leading edges of the cell intercolates MSP dimers onto the tips of growing filament complexes, forcing them ...
Soofi Shauheen S SS Department of Chemical and Biological Engineering, College of Engineering, University of Wisconsin, Madison, WI 53706, United - - 2009
Recent studies indicate that the biophysical properties of the cellular microenvironment strongly influence a variety of fundamental cell behaviors. The extracellular matrix's (ECM) response to mechanical force, described mathematically as the elastic modulus, is believed to play a particularly critical role in regulatory and pathological cell behaviors. The basement membrane ...
Patwa Z - - 2009
Lytic viruses are obligate parasites whose population dynamics are necessarily coupled to the dynamics of their host-cell population. The adaptation rate of these viruses has attracted considerable scientific interest, as they are a key model organism in experimental evolution. Nevertheless, to date mathematical models of experimental evolution have largely ignored ...
Nakamasu Akiko - - 2009
The reaction-diffusion system is one of the most studied nonlinear mechanisms that generate spatially periodic structures autonomous. On the basis of many mathematical studies using computer simulations, it is assumed that animal skin patterns are the most typical examples of the Turing pattern (stationary periodic pattern produced by the reaction-diffusion ...
Li Weimin - - 2009
Early studies on cell cycle regulation were based on experiments in model systems (Yeast, Xenopus, Starfish, Drosophila) and have shaped the way we understand many events that control the cell cycle. Although these model systems are of great value, the last decade was highlighted by studies done in human cells ...
Blanchard Guy B GB Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, - - 2009
The dynamic reshaping of tissues during morphogenesis results from a combination of individual cell behaviors and collective cell rearrangements. However, a comprehensive framework to unambiguously measure and link cell behavior to tissue morphogenesis is lacking. Here we introduce such a kinematic framework, bridging cell and tissue behaviors at an intermediate, ...
Ribba B - - 2009
The aim here was to explore the potential of pharmacokinetic (PK)/pharmacodynamic (PD) and physiopathological parameters in explaining the primary effects of an anti-cancer treatment that targets cells in a specific cell cycle phase. The authors applied a theoretical multi-scale disease model of tumour growth that integrates cancer processes at the ...
Sakaguchi Hidetsugu - - 2009
We propose a kind of reaction-diffusion equations for cell differentiation, which exhibits the Turing instability. If the diffusivity of some variables is set to be infinity, we get coupled competitive reaction-diffusion equations with a global feedback term. The size ratio of each cell type is controlled by a system parameter ...
Khabiry Masoud M Center for Biomedical Engineering, Department of Medicine, Brigham and Women's Hospital Harvard Medical School, Boston, MA 021158, - - 2009
Microstructures that generate shear-protected regions in microchannels can rapidly immobilize cells for cell-based biosensing and drug screening. Here, a two-step fabrication method is used to generate double microgrooves with various depth ratios to achieve controlled double-level cell patterning while still providing shear protection. Six microgroove geometries are fabricated with different ...
Demontis Pierfranco - - 2009
Local, discrete models of self-interacting multisite adsorption cells have been shown to be able to provide a coarse-grained representation of equilibrium properties of small molecules adsorbed in nanoporous materials at the mesoscopic scale. In the present work we show how the essential statistical properties of a host cell of structured ...
Park Joong Yull - - 2009
Cells are very sensitive to various microenvironmental cues, including mechanical stress and chemical gradients. Therefore, physiologically relevant models of cells should consider how cells sense and respond to microenvironmental cues. This can be accomplished by using microfluidic systems, in which fluid physics can be realized at a nanoliter scale. Here ...
Zeng Dehong D Department of Biomedical Engineering, Northwestern University, Evanston, - - 2010
Schlemm's canal (SC) endothelial cells are likely important in the physiology and pathophysiology of the aqueous drainage system of the eye, particularly in glaucoma. The mechanical stiffness of these cells determines, in part, the extent to which they can support a pressure gradient and thus can be used to place ...
Nag Ambarish - - 2009
Ligand-induced receptor aggregation is a well-known mechanism for initiating intracellular signals but oligomerization of distal signaling molecules may also be required for signal propagation. Formation of complexes containing oligomers of the transmembrane adaptor protein, linker for the activation of T cells (LAT), has been identified as critical in mast cell ...
Wasungu L - - 2009
Electropermeabilization is a physical method to deliver molecules into cells and tissues. Clinical applications have been successfully developed for antitumoral drug delivery and clinical trials for gene electrotransfer are currently underway. However, little is known about the mechanisms involved in this transfer. The main difficulties stem from the lack of ...
Valentiner Ursula - - 2009
BACKGROUND: Inhibition of the proteasome-ubiquitin pathway has shown to exert growth inhibitory effects on several human carcinoma cell lines. In this study, the influence of bortezomib on human neuroblastoma cells was investigated. MATERIALS AND METHODS: Cell proliferation of seven human neuroblastoma cell lines under bortezomib treatment was assessed by a ...
Händel N - - 2009
Physical interactions between different cell types are a requirement for the initiation and maintenance of immune responses. The distribution pattern of cells within a tissue may result from specific cell-cell-interactions or random distribution. Tissue architecture, degree of inflammation, frequencies of cells, number of contact partners, cell type, and size as ...
Thompson Kerry - - 2009
A high percentage of patients with temporal lobe epilepsy (TLE) are refractory to conventional pharmacotherapy. The progressive neurodegenerative processes associated with a lifetime of uncontrolled seizures mandate the development of alternative approaches to treat this disease. Transplantation of inhibitory cells has been suggested as a potential therapeutic strategy to achieve ...
Yamamoto T - - 2009
Dermatofibromas are benign dermal nodules usually seen on the extremities; however, whether a dermatofibroma is a reactive fibrous hyperplasia or a true neoplasm is still unclear. Fibrous type dermatofibromas might be regarded as the symptom of local fibrotic processes and thus present a possible model of local fibrosis. Interaction between ...
Myers Catherine E CE Department of Psychology, Rutgers University-Newark, Newark, New Jersey, USA. - - 2009
We present a simple computational model of the dentate gyrus to evaluate the hypothesis that pattern separation, defined as the ability to transform a set of similar input patterns into a less-similar set of output patterns, is dynamically regulated by hilar neurons. Prior models of the dentate gyrus have generally ...
Baranyi József - - 2009
In Quantitative Microbial Risk Assessment, it is vital to understand how lag times of individual cells are distributed over a bacterial population. Such identified distributions can be used to predict the time by which, in a growth-supporting environment, a few pathogenic cells can multiply to a poisoning concentration level. We ...
Hermelink Antje - - 2009
Single cells in genetically homogeneous microbial cultures exhibit marked phenotypic heterogeneity that is considered to bolster the fitness of the whole population. Heterogeneity on the single-cell level is typically masked in conventional studies of microbial populations, which rely on data averaged across thousands or millions of cells in a sample. ...
Hirashima Tsuyoshi - - 2009
In the early kidney development, a simple epithelial tube called ureteric bud is derived from the intermediate mesoderm and undergoes a complex process of growth and terminal bifid branching. The branching of the ureteric bud is achieved by different cellular behaviors including cell proliferation and chemotaxis. In this paper, we ...
Wei Hsiang-Chun - - 2009
To be compared with the wavelength modulation technique for measuring two-dimensional (2D) cell parameters of a twisted nematic liquid crystal (TN-LC), we propose an amplitude-sensitive heterodyne ellipsometer (ASHE) of a single wavelength that is able to characterize TN-LC in 2D quantitatively. A quarter-wave plate (QWP) is rotated continuously in this ...
Gurgel Leandro Vinícius Alves - - 2009
Succinylated mercerized cellulose (cell 1) was used to synthesize an anion exchange resin. Cell 1, containing carboxylic acid groups was reacted with triethylenetetramine to introduce amine functionality to this material to obtain cell 2. Cell 2 was reacted with methyl-iodide to quaternize the amine groups from this material to obtain ...
Sasagawa, Fumiyoshi
In order to understand biological phenomena, a new mathematical field was proposed by T. Kitagawa in 1970 and it was named biomathematics. T. Kitagawa and M. Yamaguchi discussed cell spaces which are one of approaches to establish biomathematics. More than two states are introduced in the cell space. By algebraic ...
Sasagawa, Fumiyoshi
This paper is one of a series of the papers treating stable configurations in cell space. The strong-week relations between states are introduced in the local transition rule of the cell space. The local transition rule is systematically represented by the threshold type function. The pattern of stable configuration is ...
Csikász-Nagy Attila - - 2009
One of the early success stories of computational systems biology was the work done on cell-cycle regulation. The earliest mathematical descriptions of cell-cycle control evolved into very complex, detailed computational models that describe the regulation of cell division in many different cell types. On the way these models predicted several ...
Bylski-Austrow Donita I - - 2009
BACKGROUND: Hemiepiphysiodesis is a potential method to treat idiopathic juvenile scoliosis early. The purpose of the present study was to investigate a mechanism of curve creation in the pig thoracic model of spinal hemiepiphysiodesis by determining whether the structure of the vertebral growth plate varied with distance from the stapled, ...
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