WorldWideScience

Sample records for cell density heterogeneity

  1. Heterogeneous distribution of exocytotic microdomains in adrenal chromaffin cells resolved by high-density diamond ultra-microelectrode arrays.

    Science.gov (United States)

    Gosso, Sara; Turturici, Marco; Franchino, Claudio; Colombo, Elisabetta; Pasquarelli, Alberto; Carbone, Emilio; Carabelli, Valentina

    2014-08-01

    Here we describe the ability of a high-density diamond microelectrode array targeted to resolve multi-site detection of fast exocytotic events from single cells. The array consists of nine boron-doped nanocrystalline diamond ultra-microelectrodes (9-Ch NCD-UMEA) radially distributed within a circular area of the dimensions of a single cell. The device can be operated in voltammetric or chronoamperometric configuration. Sensitivity to catecholamines, tested by dose-response calibrations, set the lowest detectable concentration of adrenaline to ∼5 μm. Catecholamine release from bovine or mouse chromaffin cells could be triggered by electrical stimulation or external KCl-enriched solutions. Spikes detected from the cell apex using carbon fibre microelectrodes showed an excellent correspondence with events measured at the bottom of the cell by the 9-Ch NCD-UMEA, confirming the ability of the array to resolve single quantal secretory events. Subcellular localization of exocytosis was provided by assigning each quantal event to one of the nine channels based on its location. The resulting mapping highlights the heterogeneous distribution of secretory activity in cell microdomains of 12-27 μm2. In bovine chromaffin cells, secretion was highly heterogeneous with zones of high and medium activity in 54% of the cell surface and zones of low or no activity in the remainder. The 'non-active' ('silent') zones covered 24% of the total and persisted for 6-8 min, indicating stable location. The 9-Ch NCD-UMEA therefore appears suitable for investigating the microdomain organization of neurosecretion with high spatial resolution. PMID:24879870

  2. Density heterogeneity of the cratonic lithosphere

    DEFF Research Database (Denmark)

    Cherepanova, Yulia; Artemieva, Irina

    2015-01-01

    Using free-board modeling, we examine a vertically-averaged mantle density beneath the Archean-Proterozoic Siberian craton in the layer from the Moho down to base of the chemical boundary layer (CBL). Two models are tested: in Model 1 the base of the CBL coincides with the LAB, whereas in Model 2...... the base of the CBL is at a 180 km depth. The uncertainty of density model is <0.02 t/m3 or <0.6% with respect to primitive mantle. The results, calculated at in situ and at room temperature (SPT) conditions, indicate a heterogeneous density structure of the Siberian lithospheric mantle with a strong...... correlation between mantle density variations and the tectonic setting. Three types of cratonic mantle are recognized from mantle density anomalies. 'Pristine' cratonic regions not sampled by kimberlites have the strongest depletion with density deficit of 1.8-3.0% (and SPT density of 3.29-3.33 t/m3 as...

  3. Mean Neutron Density in Heterogeneous Media

    International Nuclear Information System (INIS)

    The paper considers the passage of neutrons through a heterogeneous medium, which may be described using the Boltzmann equation with fluctuating parameters. An approximate expression is derived for the neutron flux averaged over the fluctuations in the medium, and is valid for small fluctuations. The mean neutron flux is analysed as a function of time and energy. A periodic reactor lattice is considered as an example of a heterogeneous medium. (author)

  4. Density functional theory in surface science and heterogeneous catalysis

    DEFF Research Database (Denmark)

    Nørskov, Jens Kehlet; Scheffler, M.; Toulhoat, H.

    2006-01-01

    Solid surfaces are used extensively as catalysts throughout the chemical industry, in the energy sector, and in environmental protection. Recently, density functional theory has started providing new insight into the atomic-scale mechanisms of heterogeneous catalysis, helping to interpret the large...

  5. Can hypoxia-PET map hypoxic cell density heterogeneity accurately in an animal tumor model at a clinically obtainable image contrast?

    International Nuclear Information System (INIS)

    Background: PET allows non-invasive mapping of tumor hypoxia, but the combination of low resolution, slow tracer adduct-formation and slow clearance of unbound tracer remains problematic. Using a murine tumor with a hypoxic fraction within the clinical range and a tracer post-injection sampling time that results in clinically obtainable tumor-to-reference tissue activity ratios, we have analyzed to what extent inherent limitations actually compromise the validity of PET-generated hypoxia maps. Materials and methods: Mice bearing SCCVII tumors were injected with the PET hypoxia-marker fluoroazomycin arabinoside (FAZA), and the immunologically detectable hypoxia marker, pimonidazole. Tumors and reference tissue (muscle, blood) were harvested 0.5, 2 and 4 h after FAZA administration. Tumors were analyzed for global (well counter) and regional (autoradiography) tracer distribution and compared to pimonidazole as visualized using immunofluorescence microscopy. Results: Hypoxic fraction as measured by pimonidazole staining ranged from 0.09 to 0.32. FAZA tumor to reference tissue ratios were close to unity 0.5 h post-injection but reached values of 2 and 6 when tracer distribution time was prolonged to 2 and 4 h, respectively. A fine-scale pixel-by-pixel comparison of autoradiograms and immunofluorescence images revealed a clear spatial link between FAZA and pimonidazole-adduct signal intensities at 2 h and later. Furthermore, when using a pixel size that mimics the resolution in PET, an excellent correlation between pixel FAZA mean intensity and density of hypoxic cells was observed already at 2 h post-injection. Conclusions: Despite inherent weaknesses, PET-hypoxia imaging is able to generate quantitative tumor maps that accurately reflect the underlying microscopic reality (i.e., hypoxic cell density) in an animal model with a clinical realistic image contrast.

  6. Density functional theory in surface science and heterogeneous catalysis

    DEFF Research Database (Denmark)

    Nørskov, Jens Kehlet; Scheffler, M.; Toulhoat, H.

    2006-01-01

    Solid surfaces are used extensively as catalysts throughout the chemical industry, in the energy sector, and in environmental protection. Recently, density functional theory has started providing new insight into the atomic-scale mechanisms of heterogeneous catalysis, helping to interpret the large...... amount of experimental data gathered during the last decades. This article shows how density functional theory can be used to describe the state of the surface during reactions and the rate of catalytic reactions. It will also show how we are beginning to understand the variation in catalytic activity...

  7. Understanding cancer stem cell heterogeneity and plasticity

    Institute of Scientific and Technical Information of China (English)

    Dean G Tang

    2012-01-01

    Heterogeneity is an omnipresent feature of mammalian cells in vitro and in vivo.It has been recently realized that even mouse and human embryonic stem cells under the best culture conditions are heterogeneous containing pluripotent as well as partially committed cells.Somatic stem cells in adult organs are also heterogeneous,containing many subpopulations of self-renewing cells with distinct regenerative capacity.The differentiated progeny of adult stem cells also retain significant developmental plasticity that can be induced by a wide variety of experimental approaches.Like normal stem cells,recent data suggest that cancer stem cells(CSCs)similarly display significant phenotypic and functional heterogeneity,and that the CSC progeny can manifest diverse plasticity.Here,I discuss CSC heterogeneity and plasticity in the context of tumor development and progression,and by comparing with normal stem cell development.Appreciation of cancer cell plasticity entails a revision to the earlier concept that only the tumorigenic subset in the tumor needs to be targeted.By understanding the interrelationship between CSCs and their differentiated progeny,we can hope to develop better therapeutic regimens that can prevent the emergence of tumor cell variants that are able to found a new tumor and distant metastases.

  8. Burning Fat Fuels Leukemic Stem Cell Heterogeneity.

    Science.gov (United States)

    Thomas, Daniel; Majeti, Ravindra

    2016-07-01

    Obese leukemia patients exhibit reduced survival after chemotherapy, suggesting an important role of adipose tissue in disease progression. In this issue of Cell Stem Cell, Ye et al. (2016) reveal metabolic heterogeneity in leukemic stem cell (LSC) subpopulations and show that chemotherapy-resistant CD36+ LSCs co-opt gonadal adipose tissue to support their metabolism and survival. PMID:27392217

  9. Heterogeneity and plasticity of T helper cells.

    Science.gov (United States)

    Zhu, Jinfang; Paul, William E

    2010-01-01

    CD4 T helper (Th) cells play critical roles in adaptive immune responses. They recruit and activate other immune cells including B cells, CD8 T cells, macrophages, mast cells, neutrophils, eosinophils and basophils. Based on their functions, their pattern of cytokine secretion and their expression of specific transcription factors, Th cells, differentiated from naïve CD4 T cells, are classified into four major lineages, Th1, Th2, Th17 and T regulatory (Treg) cells, although other Th lineages may exist. Subsets of the same lineage may express different effector cytokines, reside at different locations or give rise to cells with different fates, whereas cells from different lineages may secrete common cytokines, such as IL-2, IL-9 and IL-10, resulting in massive heterogeneity of the Th cell population. In addition, the pattern of cytokine secretion may switch from that of one lineage toward another under certain circumstances, suggesting that Th cells are plastic. Tregs are also more heterogeneous and plastic than were originally thought. In this review, we summarize recent reports on heterogeneity and plasticity of Th cells, and discuss potential mechanisms and implications of such features that Th cells display. PMID:20010916

  10. Cell Load Balancing in Heterogeneous Scenarios

    DEFF Research Database (Denmark)

    Eduardo, Simao; Rodrigues, Antonio; Mihovska, Albena D.;

    2013-01-01

    Cell load imbalances in wireless networks degrade performance. Macro and small cell collocated deployments (heterogeneous scenario) constitutes a new problem for load balancing. This paper proposes a novel admission control algorithm for an optimal solution to the assignment of traffic flows. It...

  11. Tumor heterogeneity and circulating tumor cells.

    Science.gov (United States)

    Zhang, Chufeng; Guan, Yan; Sun, Yulan; Ai, Dan; Guo, Qisen

    2016-05-01

    In patients with cancer, individualized treatment strategies are generally guided by an analysis of molecular biomarkers. However, genetic instability allows tumor cells to lose monoclonality and acquire genetic heterogeneity, an important characteristic of tumors, during disease progression. Researchers have found that there is tumor heterogeneity between the primary tumor and metastatic lesions, between different metastatic lesions, and even within a single tumor (either primary or metastatic). Tumor heterogeneity is associated with heterogeneous protein functions, which lowers diagnostic precision and consequently becomes an obstacle to determining the appropriate therapeutic strategies for individual cancer patients. With the development of novel testing technologies, an increasing number of studies have attempted to explore tumor heterogeneity by examining circulating tumor cells (CTCs), with the expectation that CTCs may comprehensively represent the full spectrum of mutations and/or protein expression alterations present in the cancer. In addition, this strategy represents a minimally invasive approach compared to traditional tissue biopsies that can be used to dynamically monitor tumor evolution. The present article reviews the potential efficacy of using CTCs to identify both spatial and temporal tumor heterogeneity. This review also highlights current issues in this field and provides an outlook toward future applications of CTCs. PMID:26902424

  12. Hydrological effects of within-catchment heterogeneity of drainage density

    Science.gov (United States)

    Di Lazzaro, Michele; Zarlenga, Antonio; Volpi, Elena

    2015-02-01

    Local drainage density (dd) has been traditionally defined as the inverse of twice the distance one has to walk before encountering a channel. This formalization easily allows to derive raster-based maps of dd extracted straight off from digital elevation model data. Maps of local dd, which are continuous in space, are able to reveal the appearance of strong heterogeneities in the geological and geomorphological properties of natural landscapes across different scales. In this work we employ the information provided by these spatial maps to study the potential effects of the within-catchment variability of dd on the hydrologic response. A simple power law relationship between runoff yield at the local scale and the value of dd has been adopted; the hypothesis is supported by a large number of past empirical observations and modeling. The novel framework proposed (ddRWF) embeds this spatially variable runoff weight in the well-known Rescaled Width Function (RWF) framework, based on the more general geomorphological theory of the hydrologic response. The model is applied to four sub-basins in the Cascade Range Region (Oregon, USA) where strong contrasts in dissection patterns due the underlain geology have been broadly addressed in previous literature. The ddRWF approach is compared with the classic RWF in terms of shape, moments and peak of the simulated hydrograph response. Results hint that the variability of runoff yield due to the heterogeneity of dd (i.e. of hillslope lengths) determines a more rapid concentration of runoff, which implies shorter lag times, larger skewness and higher peak floods, especially in the case hillslope velocity is much smaller than channel velocity. The potential of the proposed framework relies on accounting for spatially variable losses related to geomorphologic heterogeneity in lumped rainfall-runoff models, still keeping the simple and robust structure of the IUH approach.

  13. Phenotype heterogeneity in cancer cell populations

    Science.gov (United States)

    Almeida, Luis; Chisholm, Rebecca; Clairambault, Jean; Escargueil, Alexandre; Lorenzi, Tommaso; Lorz, Alexander; Trélat, Emmanuel

    2016-06-01

    Phenotype heterogeneity in cancer cell populations, be it of genetic, epigenetic or stochastic origin, has been identified as a main source of resistance to drug treatments and a major source of therapeutic failures in cancers. The molecular mechanisms of drug resistance are partly understood at the single cell level (e.g., overexpression of ABC transporters or of detoxication enzymes), but poorly predictable in tumours, where they are hypothesised to rely on heterogeneity at the cell population scale, which is thus the right level to describe cancer growth and optimise its control by therapeutic strategies in the clinic. We review a few results from the biological literature on the subject, and from mathematical models that have been published to predict and control evolution towards drug resistance in cancer cell populations. We propose, based on the latter, optimisation strategies of combined treatments to limit emergence of drug resistance to cytotoxic drugs in cancer cell populations, in the monoclonal situation, which limited as it is still retains consistent features of cell population heterogeneity. The polyclonal situation, that may be understood as "bet hedging" of the tumour, thus protecting itself from different sources of drug insults, may lie beyond such strategies and will need further developments. In the monoclonal situation, we have designed an optimised therapeutic strategy relying on a scheduled combination of cytotoxic and cytostatic treatments that can be adapted to different situations of cancer treatments. Finally, we review arguments for biological theoretical frameworks proposed at different time and development scales, the so-called atavistic model (diachronic view relying on Darwinian genotype selection in the coursof billions of years) and the Waddington-like epigenetic landscape endowed with evolutionary quasi-potential (synchronic view relying on Lamarckian phenotype instruction of a given genome by reversible mechanisms), to

  14. Self-Organization in Disaster Resilient Heterogeneous Small Cell Networks

    OpenAIRE

    Zhang, Haijun; Jiang, Chunxiao; Hu, Rose Qingyang; Qian, Yi

    2015-01-01

    Heterogeneous small cell networks with overlay femtocells and macrocell is a promising solution for future heterogeneous wireless cellular communications. However, great resilience is needed in heterogeneous small cells in case of accidents, attacks and natural disasters. In this article, we first describe the network architecture of disaster resilient heterogeneous small cell networks (DRHSCNs), where several self-organization inspired approaches are applied. Based on the proposed resilient ...

  15. Heterogeneity and plasticity of epidermal stem cells

    DEFF Research Database (Denmark)

    Schepeler, Troels; Page, Mahalia E; Jensen, Kim Bak

    2014-01-01

    The epidermis is an integral part of our largest organ, the skin, and protects us against the hostile environment. It is a highly dynamic tissue that, during normal steady-state conditions, undergoes constant turnover. Multiple stem cell populations residing in autonomously maintained compartments...... facilitate this task. In this Review, we discuss stem cell behaviour during normal tissue homeostasis, regeneration and disease within the pilosebaceous unit, an integral structure of the epidermis that is responsible for hair growth and lubrication of the epithelium. We provide an up-to-date view...... of the pilosebaceous unit, encompassing the heterogeneity and plasticity of multiple discrete stem cell populations that are strongly influenced by external cues to maintain their identity and function....

  16. Heterogeneity and plasticity of epidermal stem cells

    Science.gov (United States)

    Schepeler, Troels; Page, Mahalia E.; Jensen, Kim B.

    2014-01-01

    The epidermis is an integral part of our largest organ, the skin, and protects us against the hostile environment. It is a highly dynamic tissue that, during normal steady-state conditions, undergoes constant turnover. Multiple stem cell populations residing in autonomously maintained compartments facilitate this task. In this Review, we discuss stem cell behaviour during normal tissue homeostasis, regeneration and disease within the pilosebaceous unit, an integral structure of the epidermis that is responsible for hair growth and lubrication of the epithelium. We provide an up-to-date view of the pilosebaceous unit, encompassing the heterogeneity and plasticity of multiple discrete stem cell populations that are strongly influenced by external cues to maintain their identity and function. PMID:24961797

  17. Multiple cell and population-level interactions with mouse embryonic stem cell heterogeneity.

    Science.gov (United States)

    Cannon, Danielle; Corrigan, Adam M; Miermont, Agnes; McDonel, Patrick; Chubb, Jonathan R

    2015-08-15

    Much of development and disease concerns the generation of gene expression differences between related cells sharing similar niches. However, most analyses of gene expression only assess population and time-averaged levels of steady-state transcription. The mechanisms driving differentiation are buried within snapshots of the average cell, lacking dynamic information and the diverse regulatory history experienced by individual cells. Here, we use a quantitative imaging platform with large time series data sets to determine the regulation of developmental gene expression by cell cycle, lineage, motility and environment. We apply this technology to the regulation of the pluripotency gene Nanog in mouse embryonic stem cells. Our data reveal the diversity of cell and population-level interactions with Nanog dynamics and heterogeneity, and how this regulation responds to triggers of pluripotency. Cell cycles are highly heterogeneous and cycle time increases with Nanog reporter expression, with longer, more variable cycle times as cells approach ground-state pluripotency. Nanog reporter expression is highly stable over multiple cell generations, with fluctuations within cycles confined by an attractor state. Modelling reveals an environmental component to expression stability, in addition to any cell-autonomous behaviour, and we identify interactions of cell density with both cycle behaviour and Nanog. Rex1 expression dynamics showed shared and distinct regulatory effects. Overall, our observations of multiple partially overlapping dynamic heterogeneities imply complex cell and environmental regulation of pluripotent cell behaviour, and suggest simple deterministic views of stem cell states are inappropriate. PMID:26209649

  18. Entrainment of heterogeneous glycolytic oscillations in single cells

    CERN Document Server

    Gustavsson, A -K; Mehlig, B; Goksör, M

    2015-01-01

    Cell signaling, gene expression, and metabolism are affected by cell-cell heterogeneity and random changes in the environment. The effects of such fluctuations on cell signaling and gene expression have recently been studied intensively using single-cell experiments. In metabolism heterogeneity may be particularly important because it may affect synchronisation of metabolic oscillations, an important example of cell-cell communication. This synchronisation is notoriously difficult to describe theoretically as the example of glycolytic oscillations shows: neither is the mechanism of glycolytic synchronisation understood nor the role of cell-cell heterogeneity. To pin down the mechanism and to assess its robustness and universality we have experimentally investigated the entrainment of glycolytic oscillations in individual yeast cells by periodic external perturbations. We find that oscillatory cells synchronise through phase shifts and that the mechanism is insensitive to cell heterogeneity (robustness) and si...

  19. Cell Docking, Movement and Cell-Cell Interactions of Heterogeneous Cell Suspensions in a Cell Manipulation Microdevice

    OpenAIRE

    Long-Sun Huang; Yu-Hung Wang; Yu-Wei Chung; Fei-Lung Lai; Shiaw-Min Hwang

    2011-01-01

    This study demonstrates a novel cell manipulation microdevice for cell docking, culturing, cell-cell contact and interaction by microfluidic manipulation of heterogeneous cell suspensions. Heterogeneous cell suspensions include disparate blood cells of natural killer cells and leukemia cancer cells for immune cell transplantation therapy. However, NK cell alloreactivity from different healthy donors present various recovery response levels. Little is still known about the interactions and cyt...

  20. Spatially heterogeneous dynamics investigated via a time-dependent four-point density correlation function

    DEFF Research Database (Denmark)

    Lacevic, N.; Starr, F. W.; Schrøder, Thomas;

    2003-01-01

    correlation function g4(r,t) and corresponding "structure factor" S4(q,t) which measure the spatial correlations between the local liquid density at two points in space, each at two different times, and so are sensitive to dynamical heterogeneity. We study g4(r,t) and S4(q,t) via molecular dynamics......Relaxation in supercooled liquids above their glass transition and below the onset temperature of "slow" dynamics involves the correlated motion of neighboring particles. This correlated motion results in the appearance of spatially heterogeneous dynamics or "dynamical heterogeneity." Traditional...... two-point time-dependent density correlation functions, while providing information about the transient "caging" of particles on cooling, are unable to provide sufficiently detailed information about correlated motion and dynamical heterogeneity. Here, we study a four-point, time-dependent density...

  1. Deciphering dendritic cell heterogenity in immunity

    Directory of Open Access Journals (Sweden)

    Michaël eChopin

    2012-02-01

    Full Text Available Dendritic cells (DCs are specialized antigen presenting cells that are exquisitely adapted to sense pathogens and induce the development of adaptive immune responses. They form a complex network of phenotypically and functionally distinct subsets. Within this network, individual DC subsets display highly specific roles in local immunosurveillance, migration and antigen presentation. This division of labor amongst DCs offers great potential to tune the immune response by harnessing subset-specific attributes of DCs in the clinical setting. Until recently, our understanding of DC subsets has been limited and paralleled by poor clinical translation and efficacy. We have now begun to unravel how different DC subsets develop within a complex multilayered system. These finding open up exciting possibilities for targeted manipulation of DC subsets. Furthermore, ground-breaking developments overcoming a major translational obstacle – identification of similar DC populations in mouse and man – now set the stage for significant advances in the field. Here we explore the determinants that underpin cellular and transcriptional heterogeneity within the DC network, how these influence DC distribution and localization at steady-state, and the capacity of DCs to present antigens via direct or cross-presentation during pathogen infection.

  2. A New Cell Association Scheme In Heterogeneous Networks

    OpenAIRE

    Yang, Bin; Mao, Guoqiang; Ge, Xiaohu; Han, Tao

    2015-01-01

    Cell association scheme determines which base station (BS) and mobile user (MU) should be associated with and also plays a significant role in determining the average data rate a MU can achieve in heterogeneous networks. However, the explosion of digital devices and the scarcity of spectra collectively force us to carefully re-design cell association scheme which was kind of taken for granted before. To address this, we develop a new cell association scheme in heterogeneous networks based on ...

  3. Chemotherapy in heterogeneous cultures of cancer cells with interconversion

    International Nuclear Information System (INIS)

    Recently, the interconversion between differentiated and stem-like cancer cells has been observed. Here, we model the in vitro growth of heterogeneous cell cultures in the presence of interconversion from differentiated cancer cells to cancer stem cells (CSCs), showing that, by targeting only CSC with cytotoxic agents, it is not always possible to eradicate cancer. We have determined the kinetic conditions under which cytotoxic agents in in vitro heterogeneous cultures of cancer cells eradicate cancer. In particular, we have shown that the chemotherapeutic elimination of in vitro cultures of heterogeneous cancer cells is effective only if it targets all cancer cell types, and if the induced death rates for the different subpopulations of cancer cell types are large enough. The quantitative results of the model are compared and validated with experimental data. (paper)

  4. Rapid Assembly of Heterogeneous 3D Cell Microenvironments in a Microgel Array.

    Science.gov (United States)

    Li, Yiwei; Chen, Pu; Wang, Yachao; Yan, Shuangqian; Feng, Xiaojun; Du, Wei; Koehler, Stephan A; Demirci, Utkan; Liu, Bi-Feng

    2016-05-01

    Heterogeneous 3D cell microenvironment arrays are rapidly assembled by combining surface-wettability-guided assembly and microdroplet-array-based operations. This approach enables precise control over individual shapes, sizes, chemical concentrations, cell density, and 3D spatial distribution of multiple components. This technique provides a cost-effective solution to meet the increasing demand of stem cell research, tissue engineering, and drug screening. PMID:26991071

  5. Heterogeneity and plasticity of T helper cells

    OpenAIRE

    Zhu, Jinfang; Paul, William E.

    2009-01-01

    CD4 T helper (Th) cells play critical roles in adaptive immune responses. They recruit and activate other immune cells including B cells, CD8 T cells, macrophages, mast cells, neutrophils, eosinophils and basophils. Based on their functions, their pattern of cytokine secretion and their expression of specific transcription factors, Th cells, differentiated from naïve CD4 T cells, are classified into four major lineages, Th1, Th2, Th17 and T regulatory (Treg) cells, although other Th lineages ...

  6. Gene expression heterogeneities in embryonic stem cell populations

    DEFF Research Database (Denmark)

    Martinez Arias, Alfonso; Brickman, Joshua M

    2011-01-01

    intrinsic requirement for heterogeneity with stem cell populations. We focus on Embryonic Stem (ES) cells, in vitro derived cell lines from the early embryo that are considered both pluripotent (able to generate all the lineages of the future embryo) and indefinitely self renewing. We examine the relevance......Stem and progenitor cells are populations of cells that retain the capacity to populate specific lineages and to transit this capacity through cell division. However, attempts to define markers for stem cells have met with limited success. Here we consider whether this limited success reflects an...

  7. Single-cell profiling approaches to probing tumor heterogeneity.

    Science.gov (United States)

    Khoo, Bee Luan; Chaudhuri, Parthiv Kant; Ramalingam, Naveen; Tan, Daniel Shao Weng; Lim, Chwee Teck; Warkiani, Majid Ebrahimi

    2016-07-15

    Tumor heterogeneity is a major hindrance in cancer classification, diagnosis and treatment. Recent technological advances have begun to reveal the true extent of its heterogeneity. Single-cell analysis (SCA) is emerging as an important approach to detect variations in morphology, genetic or proteomic expression. In this review, we revisit the issue of inter- and intra-tumor heterogeneity, and list various modes of SCA techniques (cell-based, nucleic acid-based, protein-based, metabolite-based and lipid-based) presently used for cancer characterization. We further discuss the advantages of SCA over pooled cell analysis, as well as the limitations of conventional techniques. Emerging trends, such as high-throughput sequencing, are also mentioned as improved means for cancer profiling. Collectively, these applications have the potential for breakthroughs in cancer treatment. PMID:26789729

  8. Spatially heterogeneous populations with mixed negative and positive local density dependence.

    Science.gov (United States)

    Knipl, Diána; Röst, Gergely

    2016-06-01

    Identifying the steady states of a population is a key issue in theoretical ecology, that includes the study of spatially heterogeneous populations. There are several examples of real ecosystems in patchy environments where the habitats are heterogeneous in their local density dependence. We investigate a multi-patch model of a single species with spatial dispersal, where the growth of the local population is logistic in some localities (negative density dependence) while other patches exhibit a strong Allee effect (positive density dependence). When the local dynamics is logistic in each patch and the habitats are interconnected by dispersal then the total population has only the extinction steady state and a componentwise positive equilibrium, corresponding to persistence in each patch. We show that animal populations in patchy environments can have a large number of steady states if local density dependence varies over the locations. It is demonstrated that, depending on the network topology of migration routes between the patches, the interaction of spatial dispersal and local density dependence can create a variety of coexisting stable positive equilibria. We give a detailed description of the multiple ways dispersal can rescue local populations from extinction. PMID:26801607

  9. Cell heterogeneity problems in the analysis of zero power experiments

    International Nuclear Information System (INIS)

    Methods are described for treating plate and pin cell heterogeneity in the preparation of broad group cross-sections used in the analysis of zero power fast reactor experiments. Methods used at Karlsruhe and Winfrith are summarised and compared, with particular reference to the treatment of resonance shielding, the calculation of broad group spatial fine structure, the treatment of leakage and the calculation of anisotropic diffusion coefficients. The problems of cells near boundaries such as core-breeder interfaces and of singularities such as control rods are also considered briefly. Numerical studies carried out to investigate approximations in the methods are described. These include tests of the accuracy of one-dimensional cell modelling techniques, and the validation by Monte Carlo of methods for treating streaming in the calculation of diffusion coefficients. Comparisons are shown between the heterogeneity effects calculated by the Karlsruhe and Winfrith methods for typical pin and plate cells used in the BIZET experimental programme, and their effect in a whole reactor calculation is indicated. Comparisons are given with measurements which provide tests of the heterogeneity calculations. These include reaction rate scans within pin and plate cells, and reaction rate measurements across sectors of pin and plate fuel, where the flux tilt is determined by the relative reactivity of the pin and plate cells. Finally, the heterogeneity problems arising in the interpretation of reaction rate measurements are discussed. (author)

  10. Heterogeneity reduces sensitivity of cell death for TNF-Stimuli

    Directory of Open Access Journals (Sweden)

    Schliemann Monica

    2011-12-01

    Full Text Available Abstract Background Apoptosis is a form of programmed cell death essential for the maintenance of homeostasis and the removal of potentially damaged cells in multicellular organisms. By binding its cognate membrane receptor, TNF receptor type 1 (TNF-R1, the proinflammatory cytokine Tumor Necrosis Factor (TNF activates pro-apoptotic signaling via caspase activation, but at the same time also stimulates nuclear factor κB (NF-κB-mediated survival pathways. Differential dose-response relationships of these two major TNF signaling pathways have been described experimentally and using mathematical modeling. However, the quantitative analysis of the complex interplay between pro- and anti-apoptotic signaling pathways is an open question as it is challenging for several reasons: the overall signaling network is complex, various time scales are present, and cells respond quantitatively and qualitatively in a heterogeneous manner. Results This study analyzes the complex interplay of the crosstalk of TNF-R1 induced pro- and anti-apoptotic signaling pathways based on an experimentally validated mathematical model. The mathematical model describes the temporal responses on both the single cell level as well as the level of a heterogeneous cell population, as observed in the respective quantitative experiments using TNF-R1 stimuli of different strengths and durations. Global sensitivity of the heterogeneous population was quantified by measuring the average gradient of time of death versus each population parameter. This global sensitivity analysis uncovers the concentrations of Caspase-8 and Caspase-3, and their respective inhibitors BAR and XIAP, as key elements for deciding the cell's fate. A simulated knockout of the NF-κB-mediated anti-apoptotic signaling reveals the importance of this pathway for delaying the time of death, reducing the death rate in the case of pulse stimulation and significantly increasing cell-to-cell variability. Conclusions Cell

  11. Topographical guidance of 3D tumor cell migration at an interface of collagen densities

    International Nuclear Information System (INIS)

    During cancer progression, metastatic cells leave the primary tumor and invade into the fibrous extracellular matrix (ECM) within the surrounding stroma. This ECM network is highly heterogeneous, and interest in understanding how this network can affect cell behavior has increased in the past several decades. However, replicating this heterogeneity has proven challenging. Here, we designed and utilized a method to create a well-defined interface between two distinct regions of high- and low-density collagen gels to mimic the heterogeneities in density found in the tumor stroma. We show that cells will invade preferentially from the high-density side into the low-density side. We also demonstrate that the net cell migration is a function of the density of the collagen in which the cells are embedded, and the difference in density between the two regions has minimal effect on cell net displacement and distance travelled. Our data further indicate that a low-to-high density interface promotes directional migration and induces formation of focal adhesion on the interface surface. Together, the current results demonstrate how ECM heterogeneities, in the form of interfacial boundaries, can affect cell migration. (paper)

  12. Parallel single-cell sequencing links transcriptional and epigenetic heterogeneity.

    Science.gov (United States)

    Angermueller, Christof; Clark, Stephen J; Lee, Heather J; Macaulay, Iain C; Teng, Mabel J; Hu, Tim Xiaoming; Krueger, Felix; Smallwood, Sébastien A; Ponting, Chris P; Voet, Thierry; Kelsey, Gavin; Stegle, Oliver; Reik, Wolf

    2016-03-01

    We report scM&T-seq, a method for parallel single-cell genome-wide methylome and transcriptome sequencing that allows for the discovery of associations between transcriptional and epigenetic variation. Profiling of 61 mouse embryonic stem cells confirmed known links between DNA methylation and transcription. Notably, the method revealed previously unrecognized associations between heterogeneously methylated distal regulatory elements and transcription of key pluripotency genes. PMID:26752769

  13. High density cell culture system

    Science.gov (United States)

    Spaulding, Glenn F. (Inventor)

    1994-01-01

    An annular culture vessel for growing mammalian cells is constructed in a one piece integral and annular configuration with an open end which is closed by an endcap. The culture vessel is rotatable about a horizontal axis by use of conventional roller systems commonly used in culture laboratories. The end wall of the endcap has tapered access ports to frictionally and sealingly receive the ends of hypodermic syringes. The syringes permit the introduction of fresh nutrient and withdrawal of spent nutrients. The walls are made of conventional polymeric cell culture material and are subjected to neutron bombardment to form minute gas permeable perforations in the walls.

  14. Explicit kinetic heterogeneity: mathematical models for interpretation of deuterium labeling of heterogeneous cell populations.

    Directory of Open Access Journals (Sweden)

    Vitaly V Ganusov

    2010-02-01

    Full Text Available Estimation of division and death rates of lymphocytes in different conditions is vital for quantitative understanding of the immune system. Deuterium, in the form of deuterated glucose or heavy water, can be used to measure rates of proliferation and death of lymphocytes in vivo. Inferring these rates from labeling and delabeling curves has been subject to considerable debate with different groups suggesting different mathematical models for that purpose. We show that the three most common models, which are based on quite different biological assumptions, actually predict mathematically identical labeling curves with one parameter for the exponential up and down slope, and one parameter defining the maximum labeling level. By extending these previous models, we here propose a novel approach for the analysis of data from deuterium labeling experiments. We construct a model of "kinetic heterogeneity" in which the total cell population consists of many sub-populations with different rates of cell turnover. In this model, for a given distribution of the rates of turnover, the predicted fraction of labeled DNA accumulated and lost can be calculated. Our model reproduces several previously made experimental observations, such as a negative correlation between the length of the labeling period and the rate at which labeled DNA is lost after label cessation. We demonstrate the reliability of the new explicit kinetic heterogeneity model by applying it to artificially generated datasets, and illustrate its usefulness by fitting experimental data. In contrast to previous models, the explicit kinetic heterogeneity model 1 provides a novel way of interpreting labeling data; 2 allows for a non-exponential loss of labeled cells during delabeling, and 3 can be used to describe data with variable labeling length.

  15. Muscle Satellite Cell Heterogeneity and Self-Renewal

    Directory of Open Access Journals (Sweden)

    Norio eMotohashi

    2014-01-01

    Full Text Available Adult skeletal muscle possesses extraordinary regeneration capacities. After muscle injury or exercise, large numbers of newly formed muscle fibers are generated within a week as a result of expansion and differentiation of a self-renewing pool of muscle stem cells termed muscle satellite cells. Normally, satellite cells are mitotically quiescent and reside beneath the basal lamina of muscle fibers. Upon regeneration, satellite cells are activated, and give rise to daughter myogenic precursor cells. After several rounds of proliferation, these myogenic precursor cells contribute to the formation of new muscle fibers. During cell division, a minor population of myogenic precursor cells returns to quiescent satellite cells as a self-renewal process. Currently, accumulating evidence has revealed the essential roles of satellite cells in muscle regeneration and the regulatory mechanisms, while it still remains to be elucidated how satellite cell self-renewal is molecularly regulated and how satellite cells are important in aging and diseased muscle. The number of satellite cells is decreased due to the changing niche during ageing, resulting in attenuation of muscle regeneration capacity. Additionally, in Duchenne muscular dystrophy (DMD patients, the loss of satellite cell regenerative capacity and decreased satellite cell number due to continuous needs for satellite cells lead to progressive muscle weakness with chronic degeneration. Thus, it is necessary to replenish muscle satellite cells continuously. This review outlines recent findings regarding satellite cell heterogeneity, asymmetric division and molecular mechanisms in satellite cell self-renewal which is crucial for maintenance of satellite cells as a muscle stem cell pool throughout life. In addition, we discuss roles in the stem cell niche for satellite cell maintenance, as well as related cell therapies for approaching treatment of DMD.

  16. Astrocyte morphology, heterogeneity and density in the developing African Giant Rat (Cricetomys gambianus

    Directory of Open Access Journals (Sweden)

    James Olukayode Olopade

    2015-05-01

    Full Text Available Astrocyte morphologies and heterogeneity were described in male African giant rats (AGR (Cricetomys gambianus, Waterhouse across three age groups (5 neonates, 5 juveniles and 5 adults using Silver impregnation method and immunohistochemistry against glia fibrillary acidic protein (GFAP. Immunopositive cell signaling, cell size and population were least in neonates, followed by adults and juveniles respectively. In neonates, astrocyte processes were mostly detected within the glia limitans of the mid and hind brain; their cell bodies measuring 32±4.8 µm in diameter against 91±5.4µm and 75± 1.9µm in juveniles and adults respectively. Astrocyte heterogeneity in juvenile and adult groups revealed eight subtypes to include fibrous astrocytes chiefly in the corpus callosum and brain stem, protoplasmic astrocytes in the cortex and dentate gyrus (DG; radial glia were found along the olfactory bulb (OB and subventricular zone (SVZ; velate astrocytes were mainly found in the cerebellum and hippocampus; marginal astrocytes close to the pia mater; Bergmann glia in the molecular layer of the cerebellum; perivascular and periventricular astrocytes in the cortex and third ventricle respectively. Cell counts from twelve anatomical regions of the brain were significantly higher in juveniles than in adults (p≤0.01 using unpaired student t-test in the cerebral cortex, pia, corpus callosum, rostral migratory stream (RMS, DG and cerebellum. Highest astrocyte count was found in the DG, while the least count was in the brain stem and sub cortex. Astrocytes along the periventricular layer of the OB are believed to be part of the radial glia system that transport newly formed cells towards the hippocampus and play roles in neurogenesis migration and homeostasis in the AGR. Therefore, astrocyte heterogeneity was examined across age groups in the AGR to determine whether age influences astrocytes population in different regions of the AGR brain and discuss

  17. Single-Cell Behavior and Population Heterogeneity: Solving an Inverse Problem to Compute the Intrinsic Physiological State Functions

    OpenAIRE

    Spetsieris, Konstantinos; Zygourakis, Kyriacos

    2011-01-01

    The dynamics of isogenic cell populations can be described by cell population balance models that account for phenotypic heterogeneity. To utilize the predictive power of these models, however, we must know the rates of single-cell reaction and division and the bivariate partition probability density function. These three intrinsic physiological state (IPS) functions can be obtained by solving an inverse problem that requires knowledge of the phenotypic distributions for the overall cell popu...

  18. Classification method for heterogeneity in monoclonal cell population

    Science.gov (United States)

    Aburatani, S.; Tashiro, K.; Kuhara, S.

    2015-09-01

    Monoclonal cell populations are known to be composed of heterogeneous subpopulations, thus complicating the data analysis. To gain clear insights into the mechanisms of cellular systems, biological data from a homogeneous cell population should be obtained. In this study, we developed a method based on Latent Profile Analysis (LPA) combined with Confirmatory Factor Analysis (CFA) to divide mixed data into classes, depending on their heterogeneity. In general cluster analysis, the number of measured points is a constraint, and thereby the data must be classified into fewer groups than the number of samples. By our newly developed method, the measured data can be divided into groups depending on their latent effects, without constraints. Our method is useful to clarify all types of omics data, including transcriptome, proteome and metabolic information.

  19. Dynamic heterogeneity and DNA methylation in embryonic stem cells.

    KAUST Repository

    Singer, Zakary S

    2014-07-01

    Cell populations can be strikingly heterogeneous, composed of multiple cellular states, each exhibiting stochastic noise in its gene expression. A major challenge is to disentangle these two types of variability and to understand the dynamic processes and mechanisms that control them. Embryonic stem cells (ESCs) provide an ideal model system to address this issue because they exhibit heterogeneous and dynamic expression of functionally important regulatory factors. We analyzed gene expression in individual ESCs using single-molecule RNA-FISH and quantitative time-lapse movies. These data discriminated stochastic switching between two coherent (correlated) gene expression states and burst-like transcriptional noise. We further showed that the "2i" signaling pathway inhibitors modulate both types of variation. Finally, we found that DNA methylation plays a key role in maintaining these metastable states. Together, these results show how ESC gene expression states and dynamics arise from a combination of intrinsic noise, coherent cellular states, and epigenetic regulation.

  20. Single cell analysis of Vibrio harveyi uncovers functional heterogeneity in response to quorum sensing signals

    Directory of Open Access Journals (Sweden)

    Anetzberger Claudia

    2012-09-01

    Full Text Available Abstract Background Vibrio harveyi and closely related species are important pathogens in aquaculture. A complex quorum sensing cascade involving three autoinducers controls bioluminescence and several genes encoding virulence factors. Single cell analysis of a V. harveyi population has already indicated intercellular heterogeneity in the production of bioluminescence. This study was undertaken to analyze the expression of various autoinducer-dependent genes in individual cells. Results Here we used reporter strains bearing promoter::gfp fusions to monitor the induction/repression of three autoinducer-regulated genes in wild type conjugates at the single cell level. Two genes involved in pathogenesis - vhp and vscP, which code for an exoprotease and a component of the type III secretion system, respectively, and luxC (the first gene in the lux operon were chosen for analysis. The lux operon and the exoprotease gene are induced, while vscP is repressed at high cell density. As controls luxS and recA, whose expression is not dependent on autoinducers, were examined. The responses of the promoter::gfp fusions in individual cells from the same culture ranged from no to high induction. Importantly, simultaneous analysis of two autoinducer induced phenotypes, bioluminescence (light detection and exoproteolytic activity (fluorescence of a promoter::gfp fusion, in single cells provided evidence for functional heterogeneity within a V. harveyi population. Conclusions Autoinducers are not only an indicator for cell density, but play a pivotal role in the coordination of physiological activities within the population.

  1. Cell Division Behaviour in a Heterogeneous Swarm Environment

    OpenAIRE

    Erskine, Adam; Herrmann, J. Michael

    2013-01-01

    We present a system of virtual particles that interact using simple kinetic rules. It is known that heterogeneous mixtures of particles are producing particularly interesting behaviours. Here we present a two-species swarm in which a behaviour emerges that resembles cell division. We show that the dividing behaviour exists across a narrow but finite band of parameters and for a wide range of population sizes. In a two dimensional environment the swarm's characteristics and dynamism manifests ...

  2. Transcriptional and phenotypical heterogeneity of Trypanosoma cruzi cell populations.

    Science.gov (United States)

    Seco-Hidalgo, Víctor; De Pablos, Luis Miguel; Osuna, Antonio

    2015-12-01

    Trypanosoma cruzi has a complex life cycle comprising pools of cell populations which circulate among humans, vectors, sylvatic reservoirs and domestic animals. Recent experimental evidence has demonstrated the importance of clonal variations for parasite population dynamics, survival and evolution. By limiting dilution assays, we have isolated seven isogenic clonal cell lines derived from the Pan4 strain of T. cruzi. Applying different molecular techniques, we have been able to provide a comprehensive characterization of the expression heterogeneity in the mucin-associated surface protein (MASP) gene family, where all the clonal isogenic populations were transcriptionally different. Hierarchical cluster analysis and sequence comparison among different MASP cDNA libraries showed that, despite the great variability in MASP expression, some members of the transcriptome (including MASP pseudogenes) are conserved, not only in the life-cycle stages but also among different strains of T. cruzi. Finally, other important aspects for the parasite, such as growth, spontaneous metacyclogenesis or excretion of different catabolites, were also compared among the clones, demonstrating that T. cruzi populations of cells are also phenotypically heterogeneous. Although the evolutionary strategy that sustains the MASP expression polymorphism remains unknown, we suggest that MASP clonal variability and phenotypic heterogeneities found in this study might provide an advantage, allowing a rapid response to environmental pressure or changes during the life cycle of T. cruzi. PMID:26674416

  3. Programming strategy for efficient modeling of dynamics in a population of heterogeneous cells

    DEFF Research Database (Denmark)

    Hald, Bjørn Olav; Hendriksen, Morten; Sørensen, Preben Graae

    2013-01-01

    Heterogeneity is a ubiquitous property of biological systems. Even in a genetically identical population of a single cell type, cell-to-cell differences are observed. Although the functional behavior of a given population is generally robust, the consequences of heterogeneity are fairly unpredict...... unpredictable. In heterogeneous populations, synchronization of events becomes a cardinal problem-particularly for phase coherence in oscillating systems....

  4. CellCODE: a robust latent variable approach to differential expression analysis for heterogeneous cell populations

    OpenAIRE

    Chikina, Maria; Zaslavsky, Elena; Sealfon, Stuart C.

    2015-01-01

    Motivation: Identifying alterations in gene expression associated with different clinical states is important for the study of human biology. However, clinical samples used in gene expression studies are often derived from heterogeneous mixtures with variable cell-type composition, complicating statistical analysis. Considerable effort has been devoted to modeling sample heterogeneity, and presently, there are many methods that can estimate cell proportions or pure cell-type expression from m...

  5. Heterogeneity of a human T-lymphoblastoid cell line

    Energy Technology Data Exchange (ETDEWEB)

    Snow, K.; Judd, W.

    1987-08-01

    A human T-lymphoblastoid cell line (Jurkat) was cloned, and four resulting sublines were characterized in a variety of ways with the objective of gaining information on heterogeneity in cell lines. Within a few weeks of cloning, distinct cellular morphologies and growth patterns became apparent in the four sublines. Growth rate measurements made over 3 months did not show any significant differences between the sublines. Surface protein profiles obtained by radioimmunoprecipitation using antisera in conjunction with extracts from (/sup 35/S)Met and /sup 125/I-labeled cells revealed differences between the sublines. Analysis of total cell DNA showed that one of the sublines possessed only half the chromosome complement of the other sublines and the parental line. Karyotyping confirmed this result and, in addition, demonstrated that chromosome numbers fluctuated around a mean value for each subline. Karyotypic variability became apparent within 2 months of cloning and tended to increase with time in culture. G-banding analysis showed that the analyzed cell populations contained distinctive cytogenetic aberrations. Properties of the cloned sublines were monitored over a 9-month period. One of the sublines that had shown heterogeneous morphology even after 6 weeks maintained the heterogeneity throughout this time. Another subline underwent a marked change in morphology (round to irregular) and growth habit (single cells to large clumps) with increasing time in culture. Interestingly, several alterations to surface proteins accompanied these growth changes. A third subline had relatively stable morphology and chromosome number throughout the 9-month period. The modal chromosome number was hypotetraploid for three sublines and the parent line, but was diploid for another subline.

  6. Intraclonal protein expression heterogeneity in recombinant CHO cells.

    Directory of Open Access Journals (Sweden)

    Warren Pilbrough

    Full Text Available Therapeutic glycoproteins have played a major role in the commercial success of biotechnology in the post-genomic era. But isolating recombinant mammalian cell lines for large-scale production remains costly and time-consuming, due to substantial variation and unpredictable stability of expression amongst transfected cells, requiring extensive clone screening to identify suitable high producers. Streamlining this process is of considerable interest to industry yet the underlying phenomena are still not well understood. Here we examine an antibody-expressing Chinese hamster ovary (CHO clone at single-cell resolution using flow cytometry and vectors, which couple light and heavy chain transcription to fluorescent markers. Expression variation has traditionally been attributed to genetic heterogeneity arising from random genomic integration of vector DNA. It follows that single cell cloning should yield a homogeneous cell population. We show, in fact, that expression in a clone can be surprisingly heterogeneous (standard deviation 50 to 70% of the mean, approaching the level of variation in mixed transfectant pools, and each antibody chain varies in tandem. Phenotypic variation is fully developed within just 18 days of cloning, yet is not entirely explained by measurement noise, cell size, or the cell cycle. By monitoring the dynamic response of subpopulations and subclones, we show that cells also undergo slow stochastic fluctuations in expression (half-life 2 to 11 generations. Non-genetic diversity may therefore play a greater role in clonal variation than previously thought. This also has unexpected implications for expression stability. Stochastic gene expression noise and selection bias lead to perturbations from steady state at the time of cloning. The resulting transient response as clones reestablish their expression distribution is not ordinarily accounted for but can contribute to declines in median expression over timescales of up to 50

  7. Recent Developments in Modeling Heteroepitaxy/Heterogeneous Nucleation by Dynamical Density Functional Theory

    Science.gov (United States)

    Podmaniczky, Frigyes; Tóth, Gyula I.; Tegze, György; Gránásy, László

    2015-11-01

    Crystallization of supersaturated liquids usually starts by epitaxial growth or by heterogeneous nucleation on foreign surfaces. Herein, we review recent advances made in modeling heteroepitaxy and heterogeneous nucleation on flat/modulated surfaces and nanoparticles within the framework of a simple dynamical density functional theory, known as the phase-field crystal model. It will be shown that the contact angle and the nucleation barrier are nonmonotonous functions of the lattice mismatch between the substrate and the crystalline phase. In continuous cooling studies for substrates with lattice mismatch, we recover qualitatively the Matthews-Blakeslee mechanism of stress release via the misfit dislocations. The simulations performed for particle-induced freezing will be confronted with recent analytical results, exploring thus the validity range of the latter. It will be demonstrated that time-dependent studies are essential, as investigations based on equilibrium properties often cannot identify the preferred nucleation pathways. Modeling of these phenomena is essential for designing materials on the basis of controlled nucleation and/or nano-patterning.

  8. C, N, and O Isotopic Heterogeneities in Low-density Supernova Graphite Grains from Orgueil

    CERN Document Server

    Groopman, Evan; Zinner, Ernst

    2014-01-01

    We report on the results of NanoSIMS isotope imaging of low-density supernova graphite grains from the Orgueil meteorite. 70 nm thick microtomed sections of three supernova graphite grains were deposited on Si wafers and isotopically imaged in the NanoSIMS. These sections contain hotspots of excesses in $^{18}O$ and $^{15}N$ which are spatially well correlated, and are likely carried by internal TiC subgrains. These hotspots are considerably more enriched in $^{18}O$ and $^{15}N$ than the host graphite grain. Correlations between $^{18}O$ and $^{15}N$ excesses indicate that the grains incorporated material from the He/C supernova zone. Isotope images of the surfaces of some grains show heterogeneities in their N and O isotope compositions, with extreme excesses in $^{15}N$ and $^{18}O$. In the microtome sections, we also observe two types of heterogeneities in the grains' C isotopic compositions: smooth, radial gradients in $^{12}C/^{13}C$, with this ratio trending toward solar with increasing radius; and hig...

  9. Characterization of size, anisotropy, and density heterogeneity of nanoparticles by sedimentation velocity

    KAUST Repository

    Demeler, Borries

    2014-08-05

    A critical problem in materials science is the accurate characterization of the size dependent properties of colloidal inorganic nanocrystals. Due to the intrinsic polydispersity present during synthesis, dispersions of such materials exhibit simultaneous heterogeneity in density ρ, molar mass M, and particle diameter d. The density increments ∂ρ/∂d and ∂ρ/∂M of these nanoparticles, if known, can then provide important information about crystal growth and particle size distributions. For most classes of nanocrystals, a mixture of surfactants is added during synthesis to control their shape, size, and optical properties. However, it remains a challenge to accurately determine the amount of passivating ligand bound to the particle surface post synthesis. The presence of the ligand shell hampers an accurate determination of the nanocrystal diameter. Using CdSe and PbS semiconductor nanocrystals, and the ultrastable silver nanoparticle (M4Ag 44(p-MBA)30), as model systems, we describe a Custom Grid method implemented in UltraScan-III for the characterization of nanoparticles and macromolecules using sedimentation velocity analytical ultracentrifugation. We show that multiple parametrizations are possible, and that the Custom Grid method can be generalized to provide high resolution composition information for mixtures of solutes that are heterogeneous in two out of three parameters. For such cases, our method can simultaneously resolve arbitrary two-dimensional distributions of hydrodynamic parameters when a third property can be held constant. For example, this method extracts partial specific volume and molar mass from sedimentation velocity data for cases where the anisotropy can be held constant, or provides anisotropy and partial specific volume if the molar mass is known. © 2014 American Chemical Society.

  10. Alpha thalassemia changes erythrocyte heterogeneity in sickle cell disease.

    OpenAIRE

    Noguchi, C T; Dover, G J; Rodgers, G P; Serjeant, G R; Antonarakis, S E; Anagnou, N P; Higgs, D R; Weatherall, D J; Schechter, A N

    1985-01-01

    Homozygous alpha-thalassemia has the beneficial effect in sickle cell anemia of reducing the hemolytic severity while changing several other hematological parameters. We examined in detail the cellular basis of some of these hematologic alterations. We find that the broad distribution in erythrocyte density and the large proportion of dense cells associated with sickle cell anemia are both reduced with coexisting alpha-thalassemia. Measurements of glycosylated hemoglobin levels as a function ...

  11. Heterogeneous occupancy and density estimates of the pathogenic fungus Batrachochytrium dendrobatidis in waters of North America.

    Directory of Open Access Journals (Sweden)

    Tara Chestnut

    Full Text Available Biodiversity losses are occurring worldwide due to a combination of stressors. For example, by one estimate, 40% of amphibian species are vulnerable to extinction, and disease is one threat to amphibian populations. The emerging infectious disease chytridiomycosis, caused by the aquatic fungus Batrachochytrium dendrobatidis (Bd, is a contributor to amphibian declines worldwide. Bd research has focused on the dynamics of the pathogen in its amphibian hosts, with little emphasis on investigating the dynamics of free-living Bd. Therefore, we investigated patterns of Bd occupancy and density in amphibian habitats using occupancy models, powerful tools for estimating site occupancy and detection probability. Occupancy models have been used to investigate diseases where the focus was on pathogen occurrence in the host. We applied occupancy models to investigate free-living Bd in North American surface waters to determine Bd seasonality, relationships between Bd site occupancy and habitat attributes, and probability of detection from water samples as a function of the number of samples, sample volume, and water quality. We also report on the temporal patterns of Bd density from a 4-year case study of a Bd-positive wetland. We provide evidence that Bd occurs in the environment year-round. Bd exhibited temporal and spatial heterogeneity in density, but did not exhibit seasonality in occupancy. Bd was detected in all months, typically at less than 100 zoospores L(-1. The highest density observed was ∼3 million zoospores L(-1. We detected Bd in 47% of sites sampled, but estimated that Bd occupied 61% of sites, highlighting the importance of accounting for imperfect detection. When Bd was present, there was a 95% chance of detecting it with four samples of 600 ml of water or five samples of 60 mL. Our findings provide important baseline information to advance the study of Bd disease ecology, and advance our understanding of amphibian exposure to free

  12. Heterogeneous occupancy and density estimates of the pathogenic fungus Batrachochytrium dendrobatidis in waters of North America

    Science.gov (United States)

    Chestnut, Tara E.; Anderson, Chauncey; Popa, Radu; Blaustein, Andrew R.; Voytek, Mary; Olson, Deanna H.; Kirshtein, Julie

    2014-01-01

    Biodiversity losses are occurring worldwide due to a combination of stressors. For example, by one estimate, 40% of amphibian species are vulnerable to extinction, and disease is one threat to amphibian populations. The emerging infectious disease chytridiomycosis, caused by the aquatic fungus Batrachochytrium dendrobatidis (Bd), is a contributor to amphibian declines worldwide. Bd research has focused on the dynamics of the pathogen in its amphibian hosts, with little emphasis on investigating the dynamics of free-living Bd. Therefore, we investigated patterns of Bd occupancy and density in amphibian habitats using occupancy models, powerful tools for estimating site occupancy and detection probability. Occupancy models have been used to investigate diseases where the focus was on pathogen occurrence in the host. We applied occupancy models to investigate free-living Bd in North American surface waters to determine Bd seasonality, relationships between Bd site occupancy and habitat attributes, and probability of detection from water samples as a function of the number of samples, sample volume, and water quality. We also report on the temporal patterns of Bd density from a 4-year case study of a Bd-positive wetland. We provide evidence that Bd occurs in the environment year-round. Bd exhibited temporal and spatial heterogeneity in density, but did not exhibit seasonality in occupancy. Bd was detected in all months, typically at less than 100 zoospores L−1. The highest density observed was ∼3 million zoospores L−1. We detected Bd in 47% of sites sampled, but estimated that Bd occupied 61% of sites, highlighting the importance of accounting for imperfect detection. When Bd was present, there was a 95% chance of detecting it with four samples of 600 ml of water or five samples of 60 mL. Our findings provide important baseline information to advance the study of Bd disease ecology, and advance our understanding of amphibian exposure to free-living Bd in aquatic

  13. Exploiting human memory B cell heterogeneity for improved vaccine efficacy

    Directory of Open Access Journals (Sweden)

    Noel Thomas Pauli

    2011-12-01

    Full Text Available The major goal in vaccination is establishment of long-term, prophylactic humoral memory to a pathogen. Two major components to long-lived humoral memory are plasma cells for the production of specific immunoglobulin and memory B cells that survey for their specific antigen in the periphery for later affinity maturation, proliferation, and differentiation. The study of human B cell memory has been aided by the discovery of a general marker for B cell memory, expression of CD27; however, new data suggests the existence of CD27- memory B cells as well. These recently described non-canonical memory populations have increasingly pointed to the heterogeneity of the memory compartment. The novel B memory subsets in humans appear to have unique origins, localization, and functions compared to what was considered to be a classical memory B cell. In this article, we review the known B cell memory subsets, the establishment of B cell memory in vaccination and infection, and how understanding these newly described subsets can inform vaccine design and disease treatment.

  14. Heterogeneous electrocatalysis in porous cathodes of solid oxide fuel cells

    CERN Document Server

    Fu, Y; Bertei, A; Qi, C; Mohanram, A; Pietras, J D; Bazant, M Z

    2014-01-01

    A general physics-based model is developed for heterogeneous electrocatalysis in porous electrodes and used to predict and interpret the impedance of solid oxide fuel cells. This model describes the coupled processes of oxygen gas dissociative adsorption and surface diffusion of the oxygen intermediate to the triple phase boundary, where charge transfer occurs. The model accurately captures the Gerischer-like frequency dependence and the oxygen partial pressure dependence of the impedance of symmetric cathode cells. Digital image analysis of the microstructure of the cathode functional layer in four different cells directly confirms the predicted connection between geometrical properties and the impedance response. As in classical catalysis, the electrocatalytic activity is controlled by an effective Thiele modulus, which is the ratio of the surface diffusion length (mean distance from an adsorption site to the triple phase boundary) to the surface boundary layer length (square root of surface diffusivity div...

  15. Pico Cell Densification Study in LTE Heterogeneous Networks

    OpenAIRE

    Cong, Guanglei

    2012-01-01

    Heterogeneous Network (HetNet) deployment has been considered as the main approach to boost capacity and coverage in Long Term Evolu-tion (LTE) networks in order to fulfill the huge future demand on mo-bile broadband usage. In order to study the improvement on network performance, i.e. capacity, coverage and user throughput, from pico cell densification in LTE HetNets, a network densification algorithm which determines the placement locations of the pico sites based on pathloss has been desig...

  16. Clustering Based on Node Density in Heterogeneous Under-Water Sensor Network

    Directory of Open Access Journals (Sweden)

    Sharad Saxena

    2013-06-01

    Full Text Available An underwater sensor network comprise of sensors and vehicles to perform numerous tasks. In underwater ad-hoc sensor network acoustic signals are transmitted through multi-hop sequence so as to save sensors’ energy and to achieve longer life time. Re-charging batteries of deep water deployed sensors is practically not feasible. Clustering is the best strategy to achieve efficient multi-hopping, where cluster head is made responsible to collect local data and forward it to the sink. Cluster-head selection is the challenging job in a cluster, as it loses its energy in transmitting its own data and aggregated data, as compared to other sensors. In this paper we have proposed an Under Water Density Based Clustered Sensor Network (UWDBCSN scheme using heterogeneous sensors. The scheme utilizes two types of sensors: one having high energy capacity, working as cluster head, having small quantity and other are ordinary sensors in huge quantity. Further cluster-head selection is based on node degree i.e. the density of the sensors in a region. The proposed scheme is found to be more energy efficient helps in extending the life time of underwater sensor networks.

  17. Contribution of mass density heterogeneities to the quasigeoid-to-geoid separation

    Science.gov (United States)

    Tenzer, Robert; Hirt, Christian; Novák, Pavel; Pitoňák, Martin; Šprlák, Michal

    2016-01-01

    -to-quasigeoid separation globally varies within -4.19 and 0.26 m while the corresponding values computed according to a classical definition are only negative and reach extreme values of -3.5 m. A comparison of these results reveals that inaccuracies caused by disregarding the terrain geometry and mass density heterogeneities distributed within the topography and below the geoid surface can reach ± 2 m or more in the mountainous regions.

  18. Does heterogeneity of pimonidazole labelling correspond to the heterogeneity of radiation-response of FaDu human squamous cell carcinoma?

    International Nuclear Information System (INIS)

    Background and purpose: Pimonidazole is a marker for hypoxic cells which are radioresistant and thereby important for the outcome of radiotherapy. The present study evaluates heterogeneity in pimonidazole binding within and between tumours and relates the results to the heterogeneity of radiation response in the same tumour cell line. Materials and methods: FaDu, a poorly differentiated human squamous cell carcinoma line, was transplanted subcutaneously into the right hind-leg of NMRI nude mice. Tumours were irradiated with graded single doses either under ambient or clamped blood flow conditions and local tumour control was evaluated after 120 days. Complete dose-response curves for local tumour control were generated and the slope, a measure of heterogeneity of radiation response, was determined. In parallel, 12 unirradiated tumours were examined histologically. Seven serial 10 μm cross-sections per tumour were evaluated using fluorescence microscopy and computerised image analysis to determine the pimonidazole hypoxic fraction (pHF). Heterogeneity in pHF was quantified by its coefficient of variation (CV). Poisson-based model calculations considering the intertumoural heterogeneity of pHF were performed and the slopes of the predicted and the observed dose-response curves were compared. Results: The mean pHF was 11% [CV 50%] when one central section per tumour was evaluated. Measurements of multiple sections per tumour resulted in a mean pHF of 12% [CV 46%] (P=0.7). Intertumoural heterogeneity in pHF was more pronounced than heterogeneity in individual tumours by a factor of 2. Model calculations based on the variability in pHF resulted in similar slopes of the dose-response curve for local tumour control in comparison with the observed slope when the heterogeneity in an unknown and arbitrarily chosen additional radiobiologically relevant parameter, in this example clonogen density, was taken into account. Conclusions: While the average pimonidazole hypoxic

  19. Tumor cell heterogeneity: impact on mechanisms of therapeutic drug resistance

    International Nuclear Information System (INIS)

    Purpose: The aim of these studies was to determine whether chemotherapy-resistant tumor cell sublines derived from a single starting cell population with identical treatment protocols, have the same mechanism of resistance. Methods and Materials: Twelve cyclophosphamide-resistant sublines were derived from KHT-iv murine sarcoma cells by repeated exposures to 2, 4, or 8 μg/ml doses of 4-hydroperoxycyclophosphamide (4-OOHCP). To investigate possible mechanisms of resistance, glutathione (GSH) levels, glutathione S-transferase (GST) activity, and aldehyde dehydrogenase (ALDH) activity were determined. In addition, studies with the GSH depletor buthionine sulfoximine (BSO) and the ALDH inhibitor diethylamino-benzaldehyde (DEAB) were undertaken. Results: Resistant factors to 4-OOHCP, assessed at 10% clonogenic cell survival, ranged from 1.5-7.0 for the various cell lines. Crossresistance to melphalan and adriamycin also were commonly observed. Increased GSH levels, GST activity and ALDH activity were detected in the sublines but not all exhibited the same pattern of biochemical alterations. The response to GSH and ALDH inhibitors also varied among the sublines; the resistance being reversible in some cell lines but not others. Conclusion: The present results indicate that when resistant sublines are derived simultaneously from the same starting cell population, the observed mechanisms of resistance may not be the same in each of the variants. These findings support the hypothesis that preexisting cellular heterogeneity may affect mechanisms of acquired resistance

  20. Simulation of density-driven flow in heterogeneous and fractured porous media

    Energy Technology Data Exchange (ETDEWEB)

    Grillo, A. [Politecnico di Torino (Italy). DISMA; Logashenko, D. [Steinbeis Research Center, Oelbronn (Germany); Stichel, S.; Wittum, G. [Frankfurt Univ., Frankfurt am Main (Germany). G-CSC

    2015-07-01

    The study of fractured porous media is an important and challenging problem in hydrogeology. One of the difficulties is that mathematical models have to account for heterogeneity introduced by fractures in hydrogeological media. Heterogeneity may strongly influence the physical processes taking place in these media. Moreover, the thickness of the fractures, which is usually negligible in comparison with the size of the whole domain, and the complicated geometry of fracture networks reduce essentially the efficiency of numerical methods. In order to overcome these difficulties, fractures are sometimes considered as objects of reduced dimensionality (surfaces in three dimensions), and the field equations are averaged along the fracture width. Fractures are assumed to be thin regions of space filled with a porous material whose properties differ from those of the porous medium enclosing them. The interfaces separating the fractures from the embedding medium are assumed to be ideal. We consider two approaches: (i) the fractures have the same dimension, d, as the embedding medium and are said to be d-dimensional; (ii) the fractures are considered as (d-1)-dimensional manifolds, and the equations of density-driven flow are found by averaging the d-dimensional laws over the fracture width. We show that the second approach is a valid alternative to the first one. For this purpose, we perform numerical experiments using a finite-volume discretization for both approaches. The results obtained by the two methods are in good agreement with each other. We derive a criterion for the validity of the simplified representation. The criterion characterizes the transition of a mainly parallel flow to a rotational flow, which cannot be reasonably approximated using a d-1 dimensional representation. We further present a numerical algorithm using adaptive dimensional representation.

  1. Single Cell Proteolytic Assays to Investigate Cancer Clonal Heterogeneity and Cell Dynamics Using an Efficient Cell Loading Scheme

    Science.gov (United States)

    Chen, Yu-Chih; Cheng, Yu-Heng; Ingram, Patrick; Yoon, Euisik

    2016-01-01

    Proteolytic degradation of the extracellular matrix (ECM) is critical in cancer invasion, and recent work suggests that heterogeneous cancer populations cooperate in this process. Despite the importance of cell heterogeneity, conventional proteolytic assays measure average activity, requiring thousands of cells and providing limited information about heterogeneity and dynamics. Here, we developed a microfluidic platform that provides high-efficiency cell loading and simple valveless isolation, so the proteolytic activity of a small sample (10–100 cells) can be easily characterized. Combined with a single cell derived (clonal) sphere formation platform, we have successfully demonstrated the importance of microenvironmental cues for proteolytic activity and also investigated the difference between clones. Furthermore, the platform allows monitoring single cells at multiple time points, unveiling different cancer cell line dynamics in proteolytic activity. The presented tool facilitates single cell proteolytic analysis using small samples, and our findings illuminate the heterogeneous and dynamic nature of proteolytic activity. PMID:27283981

  2. Single Cell Proteolytic Assays to Investigate Cancer Clonal Heterogeneity and Cell Dynamics Using an Efficient Cell Loading Scheme

    Science.gov (United States)

    Chen, Yu-Chih; Cheng, Yu-Heng; Ingram, Patrick; Yoon, Euisik

    2016-06-01

    Proteolytic degradation of the extracellular matrix (ECM) is critical in cancer invasion, and recent work suggests that heterogeneous cancer populations cooperate in this process. Despite the importance of cell heterogeneity, conventional proteolytic assays measure average activity, requiring thousands of cells and providing limited information about heterogeneity and dynamics. Here, we developed a microfluidic platform that provides high-efficiency cell loading and simple valveless isolation, so the proteolytic activity of a small sample (10–100 cells) can be easily characterized. Combined with a single cell derived (clonal) sphere formation platform, we have successfully demonstrated the importance of microenvironmental cues for proteolytic activity and also investigated the difference between clones. Furthermore, the platform allows monitoring single cells at multiple time points, unveiling different cancer cell line dynamics in proteolytic activity. The presented tool facilitates single cell proteolytic analysis using small samples, and our findings illuminate the heterogeneous and dynamic nature of proteolytic activity.

  3. High power density carbonate fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Yuh, C.; Johnsen, R.; Doyon, J.; Allen, J. [Energy Research Corp., Danbury, CT (United States)

    1996-12-31

    Carbonate fuel cell is a highly efficient and environmentally clean source of power generation. Many organizations worldwide are actively pursuing the development of the technology. Field demonstration of multi-MW size power plant has been initiated in 1996, a step toward commercialization before the turn of the century, Energy Research Corporation (ERC) is planning to introduce a 2.85MW commercial fuel cell power plant with an efficiency of 58%, which is quite attractive for distributed power generation. However, to further expand competitive edge over alternative systems and to achieve wider market penetration, ERC is exploring advanced carbonate fuel cells having significantly higher power densities. A more compact power plant would also stimulate interest in new markets such as ships and submarines where space limitations exist. The activities focused on reducing cell polarization and internal resistance as well as on advanced thin cell components.

  4. Understanding and exploiting nanoscale surface heterogeneity for particle and cell manipulation

    Science.gov (United States)

    Kalasin, Surachate

    signatures. Following the approach taken by biophysicists for describing the interactions of leukocytes with the endothelial vasculature near an injury, the state spaces in this thesis map regimes of free particle motion, immediate firm arrest, and persistent rolling against macroscopic average patch density, Debye length, particle size, and shear rate. Surprisingly, the electrostatic heterogeneity state space resembles that for selectin-mediated leukocyte motion, and reasons are put forth. This finding is important because it demonstrates how synthetic nanoscale constructs can be exploited to achieve the selective cell capture mechanism previously attributed only to specialized cell adhesion molecules. This thesis initiates studies that extend these fundamental principles, developed for a tunable and well-characterized synthetic model to biological systems. For instance, it is demonstrated that general behaviors seen with the electrostatic model are observed when fibrinogen proteins are substituted for the electrostatic patches. This shows that the nature of the attractions is immaterial to adhesion, and that the effect of added salt primarily alters the range of the electrostatic repulsion and, correspondingly, the contact area. Also, studies with Staphylococcus aureus run parallel to those employing 1 mum silica spheres, further translating the concepts. Inaugural studies with mammalian cells, in the future work section, indicate that application of the surface heterogeneity approach to cell manipulation holds much future promise.

  5. Effect of low-density heterogeneities in telecobalt therapy and validation of dose calculation algorithm of a treatment planning system

    International Nuclear Information System (INIS)

    Telecobalt machines are still prominently used for the treatment of a variety of cancer cases in developing countries. The human body is a heterogeneous composition of variety of tissues and cavities which vary widely in their physical and radiological properties. The presence of heterogeneities in the path of telecobalt beam presents an altered dose distribution in the region of clinical interests. A computerized treatment planning system (TPS) is generally used for calculating the dose distribution in the patient. Experimental measurements were carried out in a telecobalt beam with the objectives to study the effects of low-density heterogeneities and to verify the ability of the ASHA radiotherapy TPS in predicting the altered dose distribution along the central axis and off-axis of the beam. Locally available kailwood was tested for its lung equivalence and measurements were carried out in a polymethyl methacrylate phantom by introducing lung equivalent and air gap heterogeneities. A comparison of experimentally measured and TPS calculated dose values indicates that the TPS overestimates the dose by 11.6% in lung equivalent (kailwood) heterogeneity along the central axis. Similarly, it was found that the TPS overestimates the dose by 3.9% and 5.9%, respectively, with air heterogeneity of 1.0 and 2.0 cm. While testing the adequacy of TPS in off-axis region, it was found that the TPS calculation does not indicate the widening of the beam profile in the low-density heterogeneity region. This study suggests that the effective path length based algorithm of the ASHA radiotherapy TPS is unable to achieve the recommended 3% accuracy of clinical dose calculation in heterogeneous media. (author)

  6. Heterogeneous Stem Cells in Skin Homeostatis and Wound Repair

    Directory of Open Access Journals (Sweden)

    Anna Meilana

    2015-08-01

    Full Text Available BACKGROUND: The skin protects mammals from insults, infection and dehydration and enables thermoregulation and sensory perception. Various skin-resident cells carry out these diverse functions. Constant turnover of cells and healing upon injury necessitate multiple reservoirs of stem cells. The skin is a complex organ harboring several distinct populations of stem cells and a rich array of cell types. Advances in genetic and imaging tools have brought new findings about the lineage relationships between skin stem cells and their progeny. Such knowledge may offer novel avenues for therapeutics and regenerative medicine. CONTENT: In the past years, our view of the mechanisms that govern skin homeostasis and regeneration have markedly changed. New populations of stem cells have been identified that behave spatio-temporally differently in healthy tissues and in situations of damage, indicating that a great level of stem cell heterogeneity is present in the skin. There are believed to be distinct populations of stem cells in different locations. The lineages that they feed are normally constrained by signals from their local environment, but they can give rise to all epidermal lineages in response to appropriate stimuli. Given the richness of structures such as blood vessels, subcutaneous fat, innervation and the accumulation of fibroblasts under the upper parts of the rete ridges (in the case of human skin, it is reasonable to speculate that the microenvironment might be essential for interfollicular epidermal homeostasis. The bloodstream is probably the main source of long-range signals reaching the skin, and cues provided by the vascular niche might be essential for skin homeostasis. SUMMARY: A key function of the interfollicular epidermis is to act as a protective interface between the body and the external environment, and it contains several architectural elements that enable it to fulfill this function. All elements of the epidermis play

  7. Low dose transdermal estradiol induces breast density and heterogeneity changes comparable to those of raloxifene

    DEFF Research Database (Denmark)

    Nielsen, Mads; Raundahl, Jakob; Pettersen, Paola; Loog, Marco; Karemore, Gopal Raghunath; Karsdal, Morten; Christiansen, Claus

    2009-01-01

    Objective: To investigate whether transdermal low dose estradiol treatment induces changes in mammographic density or heterogeneity compared to raloxifene. Secondarily, if these changes relate to changes in bone formation/resorption markers, and if these findings indicate elevation of breast cancer...

  8. Multicellular automaticity of cardiac cell monolayers: effects of density and spatial distribution of pacemaker cells

    International Nuclear Information System (INIS)

    Self-organization of pacemaker (PM) activity of interconnected elements is important to the general theory of reaction–diffusion systems as well as for applications such as PM activity in cardiac tissue to initiate beating of the heart. Monolayer cultures of neonatal rat ventricular myocytes (NRVMs) are often used as experimental models in studies on cardiac electrophysiology. These monolayers exhibit automaticity (spontaneous activation) of their electrical activity. At low plated density, cells usually show a heterogeneous population consisting of PM and quiescent excitable cells (QECs). It is therefore highly probable that monolayers of NRVMs consist of a heterogeneous network of the two cell types. However, the effects of density and spatial distribution of the PM cells on spontaneous activity of monolayers remain unknown. Thus, a simple stochastic pattern formation algorithm was implemented to distribute PM and QECs in a binary-like 2D network. A FitzHugh–Nagumo excitable medium was used to simulate electrical spontaneous and propagating activity. Simulations showed a clear nonlinear dependency of spontaneous activity (occurrence and amplitude of spontaneous period) on the spatial patterns of PM cells. In most simulations, the first initiation sites were found to be located near the substrate boundaries. Comparison with experimental data obtained from cardiomyocyte monolayers shows important similarities in the position of initiation site activity. However, limitations in the model that do not reflect the complex beat-to-beat variation found in experiments indicate the need for a more realistic cardiomyocyte representation. (paper)

  9. Heterogeneity in white blood cells has potential to confound DNA methylation measurements.

    Directory of Open Access Journals (Sweden)

    Bjorn T Adalsteinsson

    Full Text Available Epigenetic studies are commonly conducted on DNA from tissue samples. However, tissues are ensembles of cells that may each have their own epigenetic profile, and therefore inter-individual cellular heterogeneity may compromise these studies. Here, we explore the potential for such confounding on DNA methylation measurement outcomes when using DNA from whole blood. DNA methylation was measured using pyrosequencing-based methodology in whole blood (n = 50-179 and in two white blood cell fractions (n = 20, isolated using density gradient centrifugation, in four CGIs (CpG Islands located in genes HHEX (10 CpG sites assayed, KCNJ11 (8 CpGs, KCNQ1 (4 CpGs and PM20D1 (7 CpGs. Cellular heterogeneity (variation in proportional white blood cell counts of neutrophils, lymphocytes, monocytes, eosinophils and basophils, counted by an automated cell counter explained up to 40% (p<0.0001 of the inter-individual variation in whole blood DNA methylation levels in the HHEX CGI, but not a significant proportion of the variation in the other three CGIs tested. DNA methylation levels in the two cell fractions, polymorphonuclear and mononuclear cells, differed significantly in the HHEX CGI; specifically the average absolute difference ranged between 3.4-15.7 percentage points per CpG site. In the other three CGIs tested, methylation levels in the two fractions did not differ significantly, and/or the difference was more moderate. In the examined CGIs, methylation levels were highly correlated between cell fractions. In summary, our analysis detects region-specific differential DNA methylation between white blood cell subtypes, which can confound the outcome of whole blood DNA methylation measurements. Finally, by demonstrating the high correlation between methylation levels in cell fractions, our results suggest a possibility to use a proportional number of a single white blood cell type to correct for this confounding effect in analyses.

  10. Effects of dynamic heterogeneity and density scaling of molecular dynamics on the relationship among thermodynamic coefficients at the glass transition

    International Nuclear Information System (INIS)

    In this paper, we define and experimentally verify thermodynamic characteristics of the liquid-glass transition, taking into account a kinetic origin of the process. Using the density scaling law and the four-point measure of the dynamic heterogeneity of molecular dynamics of glass forming liquids, we investigate contributions of enthalpy, temperature, and density fluctuations to spatially heterogeneous molecular dynamics at the liquid-glass transition, finding an equation for the pressure coefficient of the glass transition temperature, dTg/dp. This equation combined with our previous formula for dTg/dp, derived solely from the density scaling criterion, implies a relationship among thermodynamic coefficients at Tg. Since this relationship and both the equations for dTg/dp are very well validated using experimental data at Tg, they are promising alternatives to the classical Prigogine-Defay ratio and both the Ehrenfest equations in case of the liquid-glass transition

  11. Effect of monocular deprivation on rabbit neural retinal cell densities

    Directory of Open Access Journals (Sweden)

    Philip Maseghe Mwachaka

    2015-01-01

    Conclusion: In this rabbit model, monocular deprivation resulted in activity-dependent changes in cell densities of the neural retina in favour of the non-deprived eye along with reduced cell densities in the deprived eye.

  12. Clinical relevance of the biochemical, metabolic, and genetic factors that influence low-density lipoprotein heterogeneity.

    Science.gov (United States)

    Kwiterovich, Peter O

    2002-10-17

    Traditional risk factors for coronary artery disease (CAD) predict about 50% of the risk of developing CAD. The Adult Treatment Panel (ATP) III has defined emerging risk factors for CAD, including small, dense low-density lipoprotein (LDL). Small, dense LDL is often accompanied by increased triglycerides (TGs) and low high-density lipoprotein (HDL). An increased number of small, dense LDL particles is often missed when the LDL cholesterol level is normal or borderline elevated. Small, dense LDL particles are present in families with premature CAD and hyperapobetalipoproteinemia, familial combined hyperlipidemia, LDL subclass pattern B, familial dyslipidemic hypertension, and syndrome X. The metabolic syndrome, as defined by ATP III, incorporates a number of the components of these syndromes, including insulin resistance and intra-abdominal fat. Subclinical inflammation and elevated procoagulants also appear to be part of this atherogenic syndrome. Overproduction of very low-density lipoproteins (VLDLs) by the liver and increased secretion of large, apolipoprotein (apo) B-100-containing VLDL is the primary metabolic characteristic of most of these patients. The TG in VLDL is hydrolyzed by lipoprotein lipase (LPL) which produces intermediate-density lipoprotein. The TG in intermediate-density lipoprotein is hydrolyzed further, resulting in the generation of LDL. The cholesterol esters in LDL are exchanged for TG in VLDL by the cholesterol ester tranfer proteins, followed by hydrolysis of TG in LDL by hepatic lipase which produces small, dense LDL. Cholesterol ester transfer protein mediates a similar lipid exchange between VLDL and HDL, producing a cholesterol ester-poor HDL. In adipocytes, reduced fatty acid trapping and retention by adipose tissue may result from a primary defect in the incorporation of free fatty acids into TGs. Alternatively, insulin resistance may promote reduced retention of free fatty acids by adipocytes. Both these abnormalities lead to

  13. CellPilot: Seamless communication within Cell BE and heterogeneous clusters

    International Nuclear Information System (INIS)

    The Pilot library is targeted to novice scientific programmers within High Performance Computing. The CellPilot library extends the Pilot library to the Cell Broadband Engine processor and heterogeneous clusters. Using Pilot's process and channel abstractions, the CellPilot library can create a process on any of the processor types, both PPEs and SPEs, across the cluster. Communication is achieved by creating a channel between any two processes, and using the write/read channel functions in the participating processes. The CellPilot library uses MPI for the inter-node communication and the Cell SDK within a Cell node. All the architecture specific details of Cell communications are hidden from the user.

  14. Creative use of pilot points to address site and regional scale heterogeneity in a variable-density model

    Science.gov (United States)

    Dausman, Alyssa M.; Doherty, John; Langevin, Christian D.

    2010-01-01

    Pilot points for parameter estimation were creatively used to address heterogeneity at both the well field and regional scales in a variable-density groundwater flow and solute transport model designed to test multiple hypotheses for upward migration of fresh effluent injected into a highly transmissive saline carbonate aquifer. Two sets of pilot points were used within in multiple model layers, with one set of inner pilot points (totaling 158) having high spatial density to represent hydraulic conductivity at the site, while a second set of outer points (totaling 36) of lower spatial density was used to represent hydraulic conductivity further from the site. Use of a lower spatial density outside the site allowed (1) the total number of pilot points to be reduced while maintaining flexibility to accommodate heterogeneity at different scales, and (2) development of a model with greater areal extent in order to simulate proper boundary conditions that have a limited effect on the area of interest. The parameters associated with the inner pilot points were log transformed hydraulic conductivity multipliers of the conductivity field obtained by interpolation from outer pilot points. The use of this dual inner-outer scale parameterization (with inner parameters constituting multipliers for outer parameters) allowed smooth transition of hydraulic conductivity from the site scale, where greater spatial variability of hydraulic properties exists, to the regional scale where less spatial variability was necessary for model calibration. While the model is highly parameterized to accommodate potential aquifer heterogeneity, the total number of pilot points is kept at a minimum to enable reasonable calibration run times.

  15. Systematic Evaluation of the Prognostic Impact and Intratumour Heterogeneity of Clear Cell Renal Cell Carcinoma Biomarkers

    DEFF Research Database (Denmark)

    Gulati, Sakshi; Martinez, Pierre; Joshi, Tejal; Birkbak, Nicolai Juul; Santos, Claudio R.; Rowan, Andrew J.; Pickering, Lisa; Gore, Martin; Larkin, James; Szallasi, Zoltan Imre; Bates, Paul A.; Swanton, Charles; Gerlinger, Marco

    2014-01-01

    BackgroundCandidate biomarkers have been identified for clear cell renal cell carcinoma (ccRCC) patients, but most have not been validated. ObjectiveTo validate published ccRCC prognostic biomarkers in an independent patient cohort and to assess intratumour heterogeneity (ITH) of the most promising...... the ability of published biomarkers to predict the survival of patients with clear cell kidney cancer in an independent patient cohort. Only one molecular test adds prognostic information to routine clinical assessments. This marker showed good and poor prognosis results within most individual cancers...

  16. Nanoprobe arrays for multiple single cell insertion using heterogeneous nanosphere lithography (HNSL)

    Science.gov (United States)

    Seo, Yoon Ho; Kim, Lo Hyun; Kim, Young-Beom; Ryu, Wonhyoung

    2013-08-01

    Nanoprobe arrays for multiple single cell insertion were developed using heterogeneous nanosphere lithography. Using two heterogeneous nanoparticles as sacrificial and masking particles, high aspect ratio Si nanoprobes were fabricated in an array with spacing between the nanoprobes ranging from a few to tens of micrometers. For registered single cell analysis, multiple and precise insertion of nanoprobes into multiple single cells in a parallel fashion was demonstrated using micropipette suction and micromanipulators.

  17. DMPD: Heterogeneity of TLR-induced responses in dendritic cells: from innate toadaptive immunity. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15481153 Heterogeneity of TLR-induced responses in dendritic cells: from innate toa...w Heterogeneity of TLR-induced responses in dendritic cells: from innate toadaptive immunity. PubmedID 15481...153 Title Heterogeneity of TLR-induced responses in dendritic cells: from innate

  18. High Efficiency, High Density Terrestrial Panel. [for solar cell modules

    Science.gov (United States)

    Wohlgemuth, J.; Wihl, M.; Rosenfield, T.

    1979-01-01

    Terrestrial panels were fabricated using rectangular cells. Packing densities in excess of 90% with panel conversion efficiencies greater than 13% were obtained. Higher density panels can be produced on a cost competitive basis with the standard salami panels.

  19. Human pluripotent stem cell culture density modulates YAP signaling.

    Science.gov (United States)

    Hsiao, Cheston; Lampe, Michael; Nillasithanukroh, Songkhun; Han, Wenqing; Lian, Xiaojun; Palecek, Sean P

    2016-05-01

    Human pluripotent stem cell (hPSC) density is an important factor in self-renewal and differentiation fates; however, the mechanisms through which hPSCs sense cell density and process this information in making cell fate decisions remain to be fully understood. One particular pathway that may prove important in density-dependent signaling in hPSCs is the Hippo pathway, which is regulated by cell-cell contact and mechanosensing through the cytoskeleton and has been linked to the maintenance of stem cell pluripotency. To probe regulation of Hippo pathway activity in hPSCs, we assessed whether Hippo pathway transcriptional activator YAP was differentially modulated by cell density. At higher cell densities, YAP phosphorylation and localization to the cytoplasm increased, which led to decreased YAP-mediated transcriptional activity. Furthermore, total YAP protein levels diminished at high cell density due to the phosphorylation-targeted degradation of YAP. Inducible shRNA knockdown of YAP reduced expression of YAP target genes and pluripotency genes. Finally, the density-dependent increase of neuroepithelial cell differentiation was mitigated by shRNA knockdown of YAP. Our results suggest a pivotal role of YAP in cell density-mediated fate decisions in hPSCs. PMID:26766309

  20. Computational and experimental single cell biology techniques for the definition of cell type heterogeneity, interplay and intracellular dynamics.

    Science.gov (United States)

    de Vargas Roditi, Laura; Claassen, Manfred

    2015-08-01

    Novel technological developments enable single cell population profiling with respect to their spatial and molecular setup. These include single cell sequencing, flow cytometry and multiparametric imaging approaches and open unprecedented possibilities to learn about the heterogeneity, dynamics and interplay of the different cell types which constitute tissues and multicellular organisms. Statistical and dynamic systems theory approaches have been applied to quantitatively describe a variety of cellular processes, such as transcription and cell signaling. Machine learning approaches have been developed to define cell types, their mutual relationships, and differentiation hierarchies shaping heterogeneous cell populations, yielding insights into topics such as, for example, immune cell differentiation and tumor cell type composition. This combination of experimental and computational advances has opened perspectives towards learning predictive multi-scale models of heterogeneous cell populations. PMID:25461506

  1. Dynamics inside the cancer cell attractor reveal cell heterogeneity, limits of stability, and escape.

    Science.gov (United States)

    Li, Qin; Wennborg, Anders; Aurell, Erik; Dekel, Erez; Zou, Jie-Zhi; Xu, Yuting; Huang, Sui; Ernberg, Ingemar

    2016-03-01

    The observed intercellular heterogeneity within a clonal cell population can be mapped as dynamical states clustered around an attractor point in gene expression space, owing to a balance between homeostatic forces and stochastic fluctuations. These dynamics have led to the cancer cell attractor conceptual model, with implications for both carcinogenesis and new therapeutic concepts. Immortalized and malignant EBV-carrying B-cell lines were used to explore this model and characterize the detailed structure of cell attractors. Any subpopulation selected from a population of cells repopulated the whole original basin of attraction within days to weeks. Cells at the basin edges were unstable and prone to apoptosis. Cells continuously changed states within their own attractor, thus driving the repopulation, as shown by fluorescent dye tracing. Perturbations of key regulatory genes induced a jump to a nearby attractor. Using the Fokker-Planck equation, this cell population behavior could be described as two virtual, opposing influences on the cells: one attracting toward the center and the other promoting diffusion in state space (noise). Transcriptome analysis suggests that these forces result from high-dimensional dynamics of the gene regulatory network. We propose that they can be generalized to all cancer cell populations and represent intrinsic behaviors of tumors, offering a previously unidentified characteristic for studying cancer. PMID:26929366

  2. Cell Wall Heterogeneity in Root Development of Arabidopsis.

    Science.gov (United States)

    Somssich, Marc; Khan, Ghazanfar Abbas; Persson, Staffan

    2016-01-01

    Plant cell walls provide stability and protection to plant cells. During growth and development the composition of cell walls changes, but provides enough strength to withstand the turgor of the cells. Hence, cell walls are highly flexible and diverse in nature. These characteristics are important during root growth, as plant roots consist of radial patterns of cells that have diverse functions and that are at different developmental stages along the growth axis. Young stem cell daughters undergo a series of rapid cell divisions, during which new cell walls are formed that are highly dynamic, and that support rapid anisotropic cell expansion. Once the cells have differentiated, the walls of specific cell types need to comply with and support different cell functions. For example, a newly formed root hair needs to be able to break through the surrounding soil, while endodermal cells modify their walls at distinct positions to form Casparian strips between them. Hence, the cell walls are modified and rebuilt while cells transit through different developmental stages. In addition, the cell walls of roots readjust to their environment to support growth and to maximize nutrient uptake. Many of these modifications are likely driven by different developmental and stress signaling pathways. However, our understanding of how such pathways affect cell wall modifications and what enzymes are involved remain largely unknown. In this review we aim to compile data linking cell wall content and re-modeling to developmental stages of root cells, and dissect how root cell walls respond to certain environmental changes. PMID:27582757

  3. Cellular automata cell structure for modeling heterogeneous traffic

    OpenAIRE

    Pal, Dibyendu; C.Mallikarjuna

    2010-01-01

    Gap maintaining behavior significantly affects the traffic flow modeling under heterogeneous traffic conditions. The clearance between two adjacent moving vehicles varies depending on several traffic conditions. From the data collected on the gap maintaining behavior it has been observed that vehicles maintain different gaps when travelling under different traffic conditions and this is also influenced by lateral position of the vehicle. Mallikarjuna (2007) has found that this variable gap ma...

  4. Colorectal Cancer Classification and Cell Heterogeneity: A Systems Oncology Approach

    Directory of Open Access Journals (Sweden)

    Moisés Blanco-Calvo

    2015-06-01

    Full Text Available Colorectal cancer is a heterogeneous disease that manifests through diverse clinical scenarios. During many years, our knowledge about the variability of colorectal tumors was limited to the histopathological analysis from which generic classifications associated with different clinical expectations are derived. However, currently we are beginning to understand that under the intense pathological and clinical variability of these tumors there underlies strong genetic and biological heterogeneity. Thus, with the increasing available information of inter-tumor and intra-tumor heterogeneity, the classical pathological approach is being displaced in favor of novel molecular classifications. In the present article, we summarize the most relevant proposals of molecular classifications obtained from the analysis of colorectal tumors using powerful high throughput techniques and devices. We also discuss the role that cancer systems biology may play in the integration and interpretation of the high amount of data generated and the challenges to be addressed in the future development of precision oncology. In addition, we review the current state of implementation of these novel tools in the pathological laboratory and in clinical practice.

  5. Heterogeneity and weak coupling may explain the synchronization characteristics of cells in the arterial wall

    DEFF Research Database (Denmark)

    Jacobsen, Jens Christian Brings; Aalkjær, Christian; Matchkov, Vladimir V; Nilsson, Holger; Holstein-Rathlou, N.-H.; Freiberg, Jacob J

    2008-01-01

    development of force known as vasomotion. We present experimental data showing a considerable heterogeneity in cellular calcium dynamics in the vascular wall. In stimulated vessels, some SMCs remain quiescent, whereas others display waves of variable frequency. At the onset of vasomotion, all SMCs are...... enrolled into synchronized oscillation.Simulations of coupled SMCs show that the experimentally observed cellular recruitment, the presence of quiescent cells and the variation in oscillation frequency may arise if the cell population is phenotypically heterogeneous. In this case, quiescent cells can be...... entrained at the onset of vasomotion by the collective driving force from the synchronized oscillations in the membrane potential of the surrounding cells. Partial synchronization arises with an increase in the concentration of cyclic guanosine monophosphate, but in a heterogeneous cell population complete...

  6. Heterogeneity of Mesp1+ mesoderm revealed by single-cell RNA-seq.

    Science.gov (United States)

    Chan, Sunny Sun-Kin; Chan, Howe H W; Kyba, Michael

    2016-06-01

    Mesp1 is a transcription factor that promotes differentiation of pluripotent cells into different mesoderm lineages including hematopoietic, cardiac and skeletal myogenic. This occurs via at least two transient cell populations: a common hematopoietic/cardiac progenitor population and a common cardiac/skeletal myogenic progenitor population. It is not established whether Mesp1-induced mesoderm cells are intrinsically heterogeneous, or are simply capable of multiple lineage decisions. In the current study, we applied single-cell RNA-seq to analyze Mesp1+ mesoderm. Initial whole transcriptome analysis showed a surprising homogeneity among Mesp1-induced mesoderm cells. However, this apparent global homogeneity masked an intrinsic heterogeneity revealed by interrogating a panel of early mesoderm patterning factors. This approach enabled discovery of subpopulations primed for hematopoietic or cardiac development. These studies demonstrate the heterogeneic nature of Mesp1+ mesoderm. PMID:27131741

  7. Heterogeneous Stem Cells in Skin Homeostatis and Wound Repair

    OpenAIRE

    Anna Meilana; Nurrani Mustika Dewi; Andi Wijaya

    2015-01-01

    BACKGROUND: The skin protects mammals from insults, infection and dehydration and enables thermoregulation and sensory perception. Various skin-resident cells carry out these diverse functions. Constant turnover of cells and healing upon injury necessitate multiple reservoirs of stem cells. The skin is a complex organ harboring several distinct populations of stem cells and a rich array of cell types. Advances in genetic and imaging tools have brought new findings about the lineage relationsh...

  8. Combined effects between temporal heterogeneity of water supply, nutrient level, and population density on biomass of four broadly distributed herbaceous species.

    Science.gov (United States)

    Hagiwara, Yousuke; Kachi, Naoki; Suzuki, Jun-Ichirou

    2012-01-01

    Temporal heterogeneity of water supply affects grassland community productivity and it can interact with nutrient level and intraspecific competition. To understand community responses, the responses of individual species to water heterogeneity must be evaluated while considering the interactions of this heterogeneity with nutrient levels and population density. We compared responses of four herbaceous species grown in monocultures to various combinations of water heterogeneity, nutrient level, and population density: two grasses (Cynodon dactylon and Lolium perenne), a forb (Artemisia princeps), and a legume (Trifolium repens). Treatment effects on shoot and root biomass were analyzed. In all four species, shoot biomass was larger under homogeneous than under heterogeneous water supply. Shoot responses of L. perenne tended to be greater at high nutrient levels. Although root biomass was also larger under homogeneous water supply, effects of water heterogeneity on root biomass were not significant in the grasses. Trifolium repens showed marked root responses, particularly at high population density. Although greater shoot and root growth under homogeneous water supply appears to be a general trend among herbaceous species, our results suggested differences among species could be found in the degree of response to water heterogeneity and its interactions with nutrient level and intraspecific competition. PMID:21327692

  9. Laser-Induced Fluorescence Detection in High-Throughput Screening of Heterogeneous Catalysts and Single Cells Analysis

    International Nuclear Information System (INIS)

    Laser-induced fluorescence detection is one of the most sensitive detection techniques and it has found enormous applications in various areas. The purpose of this research was to develop detection approaches based on laser-induced fluorescence detection in two different areas, heterogeneous catalysts screening and single cell study. First, we introduced laser-induced imaging (LIFI) as a high-throughput screening technique for heterogeneous catalysts to explore the use of this high-throughput screening technique in discovery and study of various heterogeneous catalyst systems. This scheme is based on the fact that the creation or the destruction of chemical bonds alters the fluorescence properties of suitably designed molecules. By irradiating the region immediately above the catalytic surface with a laser, the fluorescence intensity of a selected product or reactant can be imaged by a charge-coupled device (CCD) camera to follow the catalytic activity as a function of time and space. By screening the catalytic activity of vanadium pentoxide catalysts in oxidation of naphthalene, we demonstrated LIFI has good detection performance and the spatial and temporal resolution needed for high-throughput screening of heterogeneous catalysts. The sample packing density can reach up to 250 x 250 subunits/cm(sub 2) for 40-(micro)m wells. This experimental set-up also can screen solid catalysts via near infrared thermography detection

  10. Laser-Induced Fluorescence Detection in High-Throughput Screening of Heterogeneous Catalysts and Single Cells Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hui Su

    2001-05-01

    Laser-induced fluorescence detection is one of the most sensitive detection techniques and it has found enormous applications in various areas. The purpose of this research was to develop detection approaches based on laser-induced fluorescence detection in two different areas, heterogeneous catalysts screening and single cell study. First, we introduced laser-induced imaging (LIFI) as a high-throughput screening technique for heterogeneous catalysts to explore the use of this high-throughput screening technique in discovery and study of various heterogeneous catalyst systems. This scheme is based on the fact that the creation or the destruction of chemical bonds alters the fluorescence properties of suitably designed molecules. By irradiating the region immediately above the catalytic surface with a laser, the fluorescence intensity of a selected product or reactant can be imaged by a charge-coupled device (CCD) camera to follow the catalytic activity as a function of time and space. By screening the catalytic activity of vanadium pentoxide catalysts in oxidation of naphthalene, we demonstrated LIFI has good detection performance and the spatial and temporal resolution needed for high-throughput screening of heterogeneous catalysts. The sample packing density can reach up to 250 x 250 subunits/cm{sub 2} for 40-{micro}m wells. This experimental set-up also can screen solid catalysts via near infrared thermography detection.

  11. Novel negative mass density resonant metamaterial unit cell

    Energy Technology Data Exchange (ETDEWEB)

    Cselyuszka, Norbert, E-mail: cselyu@yahoo.com; Sečujski, Milan, E-mail: secujski@uns.ac.rs; Crnojević-Bengin, Vesna, E-mail: bengin@uns.ac.rs

    2015-01-02

    In this paper a novel resonant unit cell of one-dimensional acoustic metamaterials is presented, which exhibits negative effective mass density. We theoretically analyze the unit cell and develop a closed analytical formula for its effective mass density. Then we proceed to demonstrate left-handed propagation of acoustic waves using the proposed unit cell. Finally, we present its dual-band version, capable of operating at two independent frequencies. - Highlights: • A novel acoustic metamaterial unit cell provides Lorentz-type resonant effective mass density. • Analytical formula for effective mass density is derived. • Acoustic bandstop medium and left-handed metamaterial based on the novel unit cell are presented. • Modified version of the unit cell, operating at two independent frequencies, is proposed.

  12. Novel negative mass density resonant metamaterial unit cell

    International Nuclear Information System (INIS)

    In this paper a novel resonant unit cell of one-dimensional acoustic metamaterials is presented, which exhibits negative effective mass density. We theoretically analyze the unit cell and develop a closed analytical formula for its effective mass density. Then we proceed to demonstrate left-handed propagation of acoustic waves using the proposed unit cell. Finally, we present its dual-band version, capable of operating at two independent frequencies. - Highlights: • A novel acoustic metamaterial unit cell provides Lorentz-type resonant effective mass density. • Analytical formula for effective mass density is derived. • Acoustic bandstop medium and left-handed metamaterial based on the novel unit cell are presented. • Modified version of the unit cell, operating at two independent frequencies, is proposed

  13. Tissue specific heterogeneity in effector immune cell response

    Directory of Open Access Journals (Sweden)

    Saba eTufail

    2013-08-01

    Full Text Available Post pathogen invasion, migration of effector T-cell subsets to specific tissue locations is of prime importance for generation of robust immune response. Effector T cells are imprinted with distinct ‘homing codes’ (adhesion molecules and chemokine receptors during activation which regulate their targeted trafficking to specific tissues. Internal cues in the lymph node microenvironment along with external stimuli from food (vitamin A and sunlight (vitamin D3 prime dendritic cells, imprinting them to play centrestage in the induction of tissue tropism in effector T cells. B cells as well, in a manner similar to effector T cells, exhibit tissue tropic migration. In this review, we have focused on the factors regulating the generation and migration of effector T cells to various tissues alongwith giving an overview of tissue tropism in B cells.

  14. Effect of heterogeneous distribution of crosslink density on physical properties of radiation vulcanized NR (Natural Rubber) latex film

    International Nuclear Information System (INIS)

    Thus a study has been carried out to investigate the effect of particle to particle variation in crosslink density on physical properties of radiation vulcanized NR latex film. NR latex was irradiated in small bottle by γ rays without vulcanization accelerator to provide latex rubber particles having homogeneous distribution of crosslink density. The doses were 30, 50, 100, 250, 300, 400, 500 and 600 kGy. Weight swelling ratio, gel fraction, tensile strength and elongation at break of the latex film from the mixed latex were measured. The vulcanization dose of this latex was 250 kGy. Then the two different latexes were mixed in a such way to adjust the average dose of 250 kGy to prepare a latex consisting of rubber particles having heterogeneous distribution of crosslink density. Tensile strength of the latex film was depressed by mixing. The reduction increased with increasing the decrease of gel fraction by mixing. However the reduction was not serious when the dose difference of two latexes was less than 200 kGy

  15. Heterogeneity of renal brush border membrane (BBM) fractions isolated by differential and density gradient centrifugation

    International Nuclear Information System (INIS)

    To differentiate BBM from proximal convoluted tubules (PCT) and from pars recta (PR), the authors isolated separately membrane fractions from superficial cortex (SC-tissue) and from juxtamedullary cortex plus outer stripe of red medulla (JM-tissue) by centrifugation in Percoll gradient. BBM separated on Percoll gradient into the higher density zone (zone A), and lower density zone (zone B). The zone B from SC-tissue membranes showed a peak with high activity of alkaline phosphatase (AP) and maltase but low activities of γ-glutamyl transferase (GGT) and leucineaminopeptidase (LAP). Membranes from JM-tissue separated into a major peak in zone A, with very high activities of GGT and LAP, markers for PR, along with lesser activity of AP. In addition, zone B showed a small peak of AP and very slight shoulder of GGT and LAP. In membranes from both SC-tissue and JM-tissue, either zone A or zone B, they found concentrative uptake of both 32Pi and L-[3H]-proline in the presence of Na+-gradient. They suggest, based on distribution of BBM marker enzymes, that membrane fraction in zone B from SC-tissue contains BBM vesicles predominantly from PCT of outer cortical nephrons. Further, BBM vesicles from JM-tissue in zone A are predominantly from PR segments and in zone B from PCT of deep nephrons

  16. Aerotactic Cell Density Variations in Bacterial Turbulence

    Science.gov (United States)

    Fernandez, Vicente; Smriga, Steven; Menolascina, Filippo; Rusconi, Roberto; Stocker, Roman

    2015-11-01

    Concentrated suspensions of motile bacteria such as Bacillus subtilis exhibit group dynamics much larger than the scale of an individual bacterium, visual similar to high Reynolds number turbulence. These suspensions represent a microscale realization of active matter. Individually, B. subtilis are also aerotactic, and will accumulate near oxygen sources. Using a microfluidic device for generating oxygen gradients, we investigate the relationship between individuals' attraction to oxygen and the collective motion resultant from hydrodynamic interactions. We focus on changes in density revealed by a fluorescently labeled sub-population of B. subtilis in the dense suspension. This approach allows us to examine changes in density during the onset of collective motion as well as fully developed bacterial turbulence.

  17. Enhancement of heterogeneous electron transfer dynamics tuning single-walled carbon nanotube forest height and density

    International Nuclear Information System (INIS)

    Electrochemical sensors are growing in number and importance. Surface modifications could enhance charge transfer properties occurring at the interfaces and carbon nanoassemblies is one of the most used strategy to improve sensitivity to measurements. However, well defined protocols of surface modification are needed in order to fabricate electrochemically effective nanostructured sensors. Therefore, we aim at investigating the electrochemical properties of single-walled carbon nanotube (SWCNT) forests as a function of height and nanotube surface density. Height of the forests is accurately controlled tuning the oxidation temperatures in the range of 293–313 K of SWCNTs. The surface density of carbon nanotubes was adjusted developing cysteamine/2-mercaptoethanol (CYS/ME) self-assembled monolayers (SAMs) on gold surfaces at different ratios (1:0, 1:3, 1:10, 1:100, 0:1). Apparent electron transfer rate was analyzed with electrochemical impedance spectroscopy (EIS) and experimental data show that transfer rate constant, kapp, increases from 1 × 10−4 cm/s to 6 × 10−4 cm/s rising oxidation temperatures (i.e. lowering forest height); therefore forests with reduced height show higher electron transfer rate without significant difference in electrodic reversibility. On the other hand, tuning SWCNT surface density, forests obtained with no ME show optimal Δpeak value of 0.087 ± 0.015 V and highest kapp value of 9.15 × 10−3 cm/s. Surprisingly, electrochemical surface area analysis shows that samples with lower amount of cysteamine have an active surface area three times bigger than samples with 1:3 CYS/ME ratio. Low electrochemical efficiency associated with high active surface may be related to unwanted SWCNT bundles adsorbed on the surface for 1:10 and 1:100 CYS/ME ratio samples as confirmed by AFM morphological characterization. Further investigation shows that a transition from a semi-infinite planar diffusion mechanism to a radial diffusion one takes place

  18. Non-genetic heterogeneity, criticality and cell differentiation

    International Nuclear Information System (INIS)

    The different cell types in a living organism acquire their identity through the process of cell differentiation in which multipotent progenitor cells differentiate into distinct cell types. Experimental evidence and analysis of large-scale microarray data establish the key role played by a two-gene motif in cell differentiation in a number of cell systems. The two genes express transcription factors which repress each other's expression and autoactivate their own production. A number of theoretical models have recently been proposed based on the two-gene motif to provide a physical understanding of how cell differentiation occurs. In this paper, we study a simple model of cell differentiation which assumes no cooperativity in the regulation of gene expression by the transcription factors. The latter repress each other's activity directly through DNA binding and indirectly through the formation of heterodimers. We specifically investigate how deterministic processes combined with stochasticity contribute in bringing about cell differentiation. The deterministic dynamics of our model give rise to a supercritical pitchfork bifurcation from an undifferentiated stable steady state to two differentiated stable steady states. The stochastic dynamics of our model are studied using the approaches based on the Langevin equations and the linear noise approximation. The simulation results provide a new physical understanding of recent experimental observations. We further propose experimental measurements of quantities like the variance and the lag-1 autocorrelation function in protein fluctuations as the early signatures of an approaching bifurcation point in the cell differentiation process. (paper)

  19. Constructing a High Density Cell Culture System

    Science.gov (United States)

    Spaulding, Glenn F. (Inventor)

    1996-01-01

    An annular culture vessel for growing mammalian cells is constructed in a one piece integral and annular configuration with an open end which is closed by an endcap. The culture vessel is rotatable about a horizontal axis by use of conventional roller systems commonly used in culture laboratories. The end wall of the endcap has tapered access ports to frictionally and sealingly receive the ends of hypodermic syringes. The syringes permit the introduction of fresh nutrient and withdrawal of spent nutrients. The walls are made of conventional polymeric cell culture material and are subjected to neutron bombardment to form minute gas permeable perforations in the walls.

  20. Modelling Spread of Oncolytic Viruses in Heterogeneous Cell Populations

    Science.gov (United States)

    Ellis, Michael; Dobrovolny, Hana

    2014-03-01

    One of the most promising areas in current cancer research and treatment is the use of viruses to attack cancer cells. A number of oncolytic viruses have been identified to date that possess the ability to destroy or neutralize cancer cells while inflicting minimal damage upon healthy cells. Formulation of predictive models that correctly describe the evolution of infected tumor systems is critical to the successful application of oncolytic virus therapy. A number of different models have been proposed for analysis of the oncolytic virus-infected tumor system, with approaches ranging from traditional coupled differential equations such as the Lotka-Volterra predator-prey models, to contemporary modeling frameworks based on neural networks and cellular automata. Existing models are focused on tumor cells and the effects of virus infection, and offer the potential for improvement by including effects upon normal cells. We have recently extended the traditional framework to a 2-cell model addressing the full cellular system including tumor cells, normal cells, and the impacts of viral infection upon both populations. Analysis of the new framework reveals complex interaction between the populations and potential inability to simultaneously eliminate the virus and tumor populations.

  1. Heterogeneity in proliferative potential of ovine mesenchymal stem cell colonies.

    Science.gov (United States)

    Rhodes, N P; Srivastava, J K; Smith, R F; Longinotti, C

    2004-04-01

    Bone marrow biopsies were taken from the iliac crest of 28 individual sheep from three different breeds, ranging in age from 4 months to 8 years and mesenchymal stem cells (MSCs) isolated using selection due to plastic adherence. Cells were cultured in medium that had been selected for its effect on observed MSC proliferation, until populations of greater than 50 million had been obtained from each biopsy. The identity of the isolated cell populations as progenitors of the mesenchymal lineage was verified by deriving both osteoblastic and chondrocytic phenotypes when cultured in osteogenic and chondrogenic medium supplements, respectively. The rate of cell proliferation for each marrow biopsy was measured at each passage and the number of initial stem cells in each sample estimated. There was no statistically significant correlation between the age of the sheep and MSC proliferative potential, or age and estimated initial MSC number. There was no apparent significant difference between proliferation rate and sheep breed and colonies established from frozen cells grew at similar rates to pre-frozen cells. Counter intuitively, there appeared to be a negatively correlated trend between proliferation rate and MSC concentration in the samples. It is concluded that no initial descriptive statistics of the marrow biopsies can assist in estimating the proliferative potential, and therefore the timing of future surgeries, of MSCs sampled for the purposes of tissue engineering. PMID:15332606

  2. Cell heterogeneity problems in the analysis of zero-power experiments

    International Nuclear Information System (INIS)

    Methods are described for treating plate and pin cell heterogeneity in the preparation of broad group cross-sections used in the analysis of zero-power fast reactor experiments. Methods used at Karlsruhe and Winfrith are summarized and compared, with particular reference to the treatment of resonance shielding, the calculation of broad group spatial fine structure, the treatment leakage and the calculation of anisotropic diffusion coefficients. The problems of cells near boundaries such as core-breeder interfaces and of singularities such as control rods are also considered briefly. Numerical studies carried out to investigate approximations in the methods are described. These include tests of the accuracy of one-dimensional cell-modelling techniques, and the validation by Monte Carlo of methods for treating streaming in the calculation of diffusion coefficients. Comparisons are shown between the heterogeneity effects calculated by the Karlsruhe and Winfrith methods for typical pin and plate cells used in the BIZET experimental programme, and their effect in a whole reactor calculation is indicated. Comparisons are given with measurements which provide tests of the heterogeneity calculations. These include reaction rate scans within pin and plate cells, and reaction rate measurements across sectors of pin and plate fuel, where the flux tilt is determined by the relative reactivity of the pin and plate cells. Finally, the heterogeneity problems arising in the interpretation of reaction rate measurements are discussed. (author)

  3. Microselection - Affinity Selecting Antibodies against a Single Rare Cell in a Heterogeneous Population

    DEFF Research Database (Denmark)

    Sørensen, Morten Draeby; Agerholm, Inge Errebo; Christensen, Britta; Kølvraa, Steen; Kristensen, Peter

    2010-01-01

    antibodies. Here we have generated a microselection method allowing antibody selection, by phage display, targeting a single cell in a heterogeneous population. One K562 cell (female origin) was positioned on glass-slide among millions of lymphocytes from male donor, identifying the K562 cell by FISH (XX......). Several single cell selections were performed on such individual slides. The phage particles bound to the target cell is protected by a minute disc, while inactivating all remaining phage by UV-irradiation; leaving only the phage bound to the target cell viable. We hereby retrieved up to eight antibodies...

  4. Intraclonal Protein Expression Heterogeneity in Recombinant CHO Cells

    OpenAIRE

    Pilbrough, Warren; Munro, Trent P.; Gray, Peter

    2009-01-01

    Therapeutic glycoproteins have played a major role in the commercial success of biotechnology in the post-genomic era. But isolating recombinant mammalian cell lines for large-scale production remains costly and time-consuming, due to substantial variation and unpredictable stability of expression amongst transfected cells, requiring extensive clone screening to identify suitable high producers. Streamlining this process is of considerable interest to industry yet the underlying phenomena are...

  5. Heterogeneous Differentiation of Human Mesenchymal Stem Cells in Response to Extended Culture in Extracellular Matrices

    OpenAIRE

    Jose A Santiago; Pogemiller, Ryan; Ogle, Brenda M.

    2009-01-01

    Extracellular matrix proteins (ECMs) guide differentiation of adult stem cells, but the temporal distribution of differentiation (i.e., heterogeneity) in a given population has not been investigated. We tested the effect of individual ECM proteins on lineage commitment of human bone marrow–derived mesenchymal stem cells (MSCs) over time. We exposed stem cell populations to ECM proteins representing the primary tissue structures of the body (i.e., collagens type I, III, IV; laminin; and fibron...

  6. Heterogeneous expression of Drosophila gustatory receptors in enteroendocrine cells.

    Directory of Open Access Journals (Sweden)

    Jeong-Ho Park

    Full Text Available The gastrointestinal tract is emerging as a major site of chemosensation in mammalian studies. Enteroendocrine cells are chemosensory cells in the gut which produce regulatory peptides in response to luminal contents to regulate gut physiology, food intake, and glucose homeostasis, among other possible functions. Increasing evidence shows that mammalian taste receptors and taste signaling molecules are expressed in enteroendocrine cells in the gut. Invertebrate models such as Drosophila can provide a simple and genetically tractable system to study the chemosensory functions of enteroendocrine cells in vivo. To establish Drosophila enteroendocrine cells as a model for studying gut chemosensation, we used the GAL4/UAS system to examine the expression of all 68 Gustatory receptors (Grs in the intestine. We find that 12 Gr-GAL4 drivers label subsets of enteroendocrine cells in the midgut, and examine colocalization of these drivers with the regulatory peptides neuropeptide F (NPF, locustatachykinin (LTK, and diuretic hormone 31 (DH31. RT-PCR analysis provides additional evidence for the presence of Gr transcripts in the gut. Our results suggest that the Drosophila Grs have chemosensory roles in the intestine to regulate physiological functions such as food uptake, nutrient absorption, or sugar homeostasis.

  7. HIPSTR and thousands of lncRNAs are heterogeneously expressed in human embryos, primordial germ cells and stable cell lines

    Science.gov (United States)

    Yunusov, Dinar; Anderson, Leticia; DaSilva, Lucas Ferreira; Wysocka, Joanna; Ezashi, Toshihiko; Roberts, R. Michael; Verjovski-Almeida, Sergio

    2016-01-01

    Eukaryotic genomes are transcribed into numerous regulatory long non-coding RNAs (lncRNAs). Compared to mRNAs, lncRNAs display higher developmental stage-, tissue-, and cell-subtype-specificity of expression, and are generally less abundant in a population of cells. Despite the progress in single-cell-focused research, the origins of low population-level expression of lncRNAs in homogeneous populations of cells are poorly understood. Here, we identify HIPSTR (Heterogeneously expressed from the Intronic Plus Strand of the TFAP2A-locus RNA), a novel lncRNA gene in the developmentally regulated TFAP2A locus. HIPSTR has evolutionarily conserved expression patterns, its promoter is most active in undifferentiated cells, and depletion of HIPSTR in HEK293 and in pluripotent H1BP cells predominantly affects the genes involved in early organismal development and cell differentiation. Most importantly, we find that HIPSTR is specifically induced and heterogeneously expressed in the 8-cell-stage human embryos during the major wave of embryonic genome activation. We systematically explore the phenomenon of cell-to-cell variation of gene expression and link it to low population-level expression of lncRNAs, showing that, similar to HIPSTR, the expression of thousands of lncRNAs is more highly heterogeneous than the expression of mRNAs in the individual, otherwise indistinguishable cells of totipotent human embryos, primordial germ cells, and stable cell lines. PMID:27605307

  8. Laser-Induced Fluorescence Detection in High-Throughput Screening of Heterogeneous Catalysts and Single Cells Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hui Su

    2001-05-25

    Laser-induced fluorescence detection is one of the most sensitive detection techniques and it has found enormous applications in various areas. The purpose of this research was to develop detection approaches based on laser-induced fluorescence detection in two different areas, heterogeneous catalysts screening and single cell study. First, the author introduced laser-induced imaging (LIFI) as a high-throughput screening technique for heterogeneous catalysts to explore the use of this high-throughput screening technique in discovery and study of various heterogeneous catalyst systems. This scheme is based on the fact that the creation or the destruction of chemical bonds alters the fluorescence properties of suitably designed molecules. By irradiating the region immediately above the catalytic surface with a laser, the fluorescence intensity of a selected product or reactant can be imaged by a charge-coupled device (CCD) camera to follow the catalytic activity as a function of time and space. By screening the catalytic activity of vanadium pentoxide catalysts in oxidation of naphthalene, they demonstrated LIFI has good detection performance and the spatial and temporal resolution needed for high-throughput screening of heterogeneous catalysts. The sample packing density can reach up to 250 x 250 subunits/cm{sup 2} for 40-{micro}m wells. This experimental set-up also can screen solid catalysts via near infrared thermography detection. In the second part of this dissertation, the author used laser-induced native fluorescence coupled with capillary electrophoresis (LINF-CE) and microscope imaging to study the single cell degranulation. On the basis of good temporal correlation with events observed through an optical microscope, they have identified individual peaks in the fluorescence electropherograms as serotonin released from the granular core on contact with the surrounding fluid.

  9. Reversible adaptive plasticity: A mechanism for neuroblastoma cell heterogeneity and chemo-resistance

    Directory of Open Access Journals (Sweden)

    Lina eChakrabarti

    2012-08-01

    Full Text Available We describe a novel form of tumor cell plasticity characterized by reversible adaptive plasticity in murine and human neuroblastoma. Two cellular phenotypes were defined by their ability to exhibit adhered, anchorage dependent (AD or sphere forming, anchorage independent (AI growth. The tumor cells could transition back and forth between the two phenotypes and the transition was dependent on the culture conditions. Both cell phenotypes exhibited stem-like features such as expression of nestin, self-renewal capacity and mesenchymal differentiation potential. The AI tumorspheres were found to be more resistant to chemotherapy and proliferated slower in vitro compared to the AD cells. Identification of specific molecular markers like MAP2, β-catenin and PDGFRβ enabled us to characterize and observe both phenotypes in established mouse tumors. Irrespective of the phenotype originally implanted in mice, tumors grown in vivo show phenotypic heterogeneity in molecular marker signatures and are indistinguishable in growth or histologic appearance. Similar molecular marker heterogeneity was demonstrated in primary human tumor specimens. Chemotherapy or growth factor receptor inhibition slowed tumor growth in mice and promoted initial loss of AD or AI heterogeneity, respectively. Simultaneous targeting of both phenotypes led to further tumor growth delay with emergence of new unique phenotypes. Our results demonstrate that neuroblastoma cells are plastic, dynamic and may optimize their ability to survive by changing their phenotype. Phenotypic switching appears to be an adaptive mechanism to unfavorable selection pressure and could explain the phenotypic and functional heterogeneity of neuroblastoma.

  10. New cadmium sulfide nanomaterial for heterogeneous organic photovoltaic cells

    Czech Academy of Sciences Publication Activity Database

    Rohovec, Jan; Toušková, J.; Toušek, J.; Schauer, F.; Kuřitka, I.

    Linköping: Linköping University Electronic Press, Linköpings universitet, 2011 - (Moshfegh, B.), s. 2815-2822. (Linköping Electronic Conference Proceedings). ISBN 978-91-7393-070-3. ISSN 1650-3740. [World renewable energy congress. Linköping (SE), 08.05.2011-13.05.2011] R&D Projects: GA ČR GA202/09/1206 Institutional research plan: CEZ:AV0Z30130516 Keywords : nanocrysaline cadmium sulfide * preparation * photovoltaic cells * photovoltaic solar cells * triethanolamine Subject RIV: DD - Geochemistry http://www.ep.liu.se/ecp/057/Complete%20Proceeding.pdf

  11. Single-cell lineage tracking analysis reveals that an established cell line comprises putative cancer stem cells and their heterogeneous progeny

    Science.gov (United States)

    Sato, Sachiko; Rancourt, Ann; Sato, Yukiko; Satoh, Masahiko S.

    2016-01-01

    Mammalian cell culture has been used in many biological studies on the assumption that a cell line comprises putatively homogeneous clonal cells, thereby sharing similar phenotypic features. This fundamental assumption has not yet been fully tested; therefore, we developed a method for the chronological analysis of individual HeLa cells. The analysis was performed by live cell imaging, tracking of every single cell recorded on imaging videos, and determining the fates of individual cells. We found that cell fate varied significantly, indicating that, in contrast to the assumption, the HeLa cell line is composed of highly heterogeneous cells. Furthermore, our results reveal that only a limited number of cells are immortal and renew themselves, giving rise to the remaining cells. These cells have reduced reproductive ability, creating a functionally heterogeneous cell population. Hence, the HeLa cell line is maintained by the limited number of immortal cells, which could be putative cancer stem cells. PMID:27003384

  12. Modeling and experimental validation of CO heterogeneous chemistry and electrochemistry in solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Yurkiv, Vitaly

    2010-12-17

    In the present work experimental and numerical modeling studies of the heterogeneously catalyzed and electrochemical oxidation of CO at Nickel/yttria-stabilized zirconia (YSZ) solid oxide fuel cell (SOFC) anode systems were performed to evaluate elementary charge-transfer reaction mechanisms taking place at the three-phase boundary of CO/CO{sub 2} gas-phase, Ni electrode, and YSZ electrolyte. Temperature-programmed desorption and reaction experiments along with density functional theory calculations were performed to determine adsorption/desorption and surface diffusion kinetics as well as thermodynamic data for the CO/CO{sub 2}/Ni and CO/CO{sub 2}/YSZ systems. Based on these data elementary reaction based models with four different charge transfer mechanisms for the electrochemical CO oxidation were developed and applied in numerical simulations of literature experimental electrochemical data such as polarization curves and impedance spectra. Comparison between simulation and experiment demonstrated that only one of the four charge transfer mechanisms can consistently reproduce the electrochemical data over a wide range of operating temperatures and CO/CO{sub 2} gas compositions. (orig.) [German] In der vorliegenden Arbeit wurden experimentelle und numerische Untersuchungen zur heterogen katalysierten und elektrochemischen Oxidation von CO an Anodensystemen (bestehend aus Nickel und yttriumdotiertem Zirkoniumdioxid, YSZ) von Festoxidbrennstoffzellen (engl. Solid Oxide Fuel Cells, SOFCs) ausgefuehrt, um den mikroskopischen Mechanismus der an der CO/CO{sub 2}-Gasphase/Ni-Elektrode/YSZ-Elektrolyt- Dreiphasen-Grenzflaeche ablaufenden Ladungsuebertragungsreaktion aufzuklaeren. Temperaturprogrammierte Desorptionsmessungen (TPD) und Temperaturprogrammierte Reaktionsmessungen (TPR) sowie Dichtefunktionaltheorierechnungen wurden ausgefuehrt, um adsorptions-, desorptions- und reaktionskinetische sowie thermodynamische Daten fuer die CO/CO{sub 2}/Ni- und CO/CO{sub 2}/YSZ

  13. Review of Adaptive Cell Selection Techniques in LTE-Advanced Heterogeneous Networks

    OpenAIRE

    Gadam, M. A.; Ahmed, Maryam Abdulazeez; Ng, Chee Kyun; Nordin, Nor Kamariah; Sali, Aduwati; Hashim, Fazirulhisyam

    2016-01-01

    Poor cell selection is the main challenge in Picocell (PeNB) deployment in Long Term Evolution- (LTE-) Advanced heterogeneous networks (HetNets) because it results in load imbalance and intercell interference. A selection technique based on cell range extension (CRE) has been proposed for LTE-Advanced HetNets to extend the coverage of PeNBs for load balancing. However, poor CRE bias setting in cell selection inhibits the attainment of desired cell splitting gains. By contrast, a cell selectio...

  14. A millifluidic study of cell-to-cell heterogeneity in growth-rate and cell-division capability in populations of isogenic cells of Chlamydomonas reinhardtii.

    Science.gov (United States)

    Damodaran, Shima P; Eberhard, Stephan; Boitard, Laurent; Rodriguez, Jairo Garnica; Wang, Yuxing; Bremond, Nicolas; Baudry, Jean; Bibette, Jérôme; Wollman, Francis-André

    2015-01-01

    To address possible cell-to-cell heterogeneity in growth dynamics of isogenic cell populations of Chlamydomonas reinhardtii, we developed a millifluidic drop-based device that not only allows the analysis of populations grown from single cells over periods of a week, but is also able to sort and collect drops of interest, containing viable and healthy cells, which can be used for further experimentation. In this study, we used isogenic algal cells that were first synchronized in mixotrophic growth conditions. We show that these synchronized cells, when placed in droplets and kept in mixotrophic growth conditions, exhibit mostly homogeneous growth statistics, but with two distinct subpopulations: a major population with a short doubling-time (fast-growers) and a significant subpopulation of slowly dividing cells (slow-growers). These observations suggest that algal cells from an isogenic population may be present in either of two states, a state of restricted division and a state of active division. When isogenic cells were allowed to propagate for about 1000 generations on solid agar plates, they displayed an increased heterogeneity in their growth dynamics. Although we could still identify the original populations of slow- and fast-growers, drops inoculated with a single progenitor cell now displayed a wider diversity of doubling-times. Moreover, populations dividing with the same growth-rate often reached different cell numbers in stationary phase, suggesting that the progenitor cells differed in the number of cell divisions they could undertake. We discuss possible explanations for these cell-to-cell heterogeneities in growth dynamics, such as mutations, differential aging or stochastic variations in metabolites and macromolecules yielding molecular switches, in the light of single-cell heterogeneities that have been reported among isogenic populations of other eu- and prokaryotes. PMID:25760649

  15. A millifluidic study of cell-to-cell heterogeneity in growth-rate and cell-division capability in populations of isogenic cells of Chlamydomonas reinhardtii.

    Directory of Open Access Journals (Sweden)

    Shima P Damodaran

    Full Text Available To address possible cell-to-cell heterogeneity in growth dynamics of isogenic cell populations of Chlamydomonas reinhardtii, we developed a millifluidic drop-based device that not only allows the analysis of populations grown from single cells over periods of a week, but is also able to sort and collect drops of interest, containing viable and healthy cells, which can be used for further experimentation. In this study, we used isogenic algal cells that were first synchronized in mixotrophic growth conditions. We show that these synchronized cells, when placed in droplets and kept in mixotrophic growth conditions, exhibit mostly homogeneous growth statistics, but with two distinct subpopulations: a major population with a short doubling-time (fast-growers and a significant subpopulation of slowly dividing cells (slow-growers. These observations suggest that algal cells from an isogenic population may be present in either of two states, a state of restricted division and a state of active division. When isogenic cells were allowed to propagate for about 1000 generations on solid agar plates, they displayed an increased heterogeneity in their growth dynamics. Although we could still identify the original populations of slow- and fast-growers, drops inoculated with a single progenitor cell now displayed a wider diversity of doubling-times. Moreover, populations dividing with the same growth-rate often reached different cell numbers in stationary phase, suggesting that the progenitor cells differed in the number of cell divisions they could undertake. We discuss possible explanations for these cell-to-cell heterogeneities in growth dynamics, such as mutations, differential aging or stochastic variations in metabolites and macromolecules yielding molecular switches, in the light of single-cell heterogeneities that have been reported among isogenic populations of other eu- and prokaryotes.

  16. Somatic Cell Fusions Reveal Extensive Heterogeneity in Basal-like Breast Cancer

    DEFF Research Database (Denmark)

    Su, Ying; Subedee, Ashim; Bloushtain-Qimron, Noga;

    2015-01-01

    heterogeneity in basal-like breast cancers that correlates with clinical outcome. We also found that protein extracts of basal-like cells are sufficient to induce a luminal-to-basal phenotypic switch, implying a trigger of basal-like autoregulatory circuits. We determined that KDM6A might be required for...

  17. A detailed approach to model transport, heterogeneous chemistry, and electrochemistry in solid-oxide fuel cells

    OpenAIRE

    Janardhanan, Vinod

    2007-01-01

    This book lays out a numerical framework for the detailed description of heterogeneous chemistry, electrochemistry and porous media transport in solid-oxide fuel cells (SOFC). Assuming hydrogen as the only electrochemically active species, a modified Butler-Volmer equation is used to model the electrochemical charge transfer.

  18. Dynamic heterogeneity as a strategy of stem cell self-renewal.

    Science.gov (United States)

    Greulich, Philip; Simons, Benjamin D

    2016-07-01

    To maintain cycling adult tissue in homeostasis the balance between proliferation and differentiation of stem cells needs to be precisely regulated. To investigate how stem cells achieve perfect self-renewal, emphasis has been placed on models in which stem cells progress sequentially through a one-way proliferative hierarchy. However, investigations of tissue regeneration have revealed a surprising degree of flexibility, with cells normally committed to differentiation able to recover stem cell competence following injury. Here, we investigate whether the reversible transfer of cells between states poised for proliferation or differentiation may provide a viable mechanism for a heterogeneous stem cell population to maintain homeostasis even under normal physiological conditions. By addressing the clonal dynamics, we show that such models of "dynamic heterogeneity" may be equally capable of describing the results of recent lineage tracing assays involving epithelial tissues. Moreover, together with competition for limited niche access, such models may provide a mechanism to render tissue homeostasis robust. In particular, in 2D epithelial layers, we show that the mechanism of dynamic heterogeneity avoids some pathological dependencies that undermine models based on a hierarchical stem/progenitor organization. PMID:27313213

  19. Designing a multicolor long range nanoscopic ruler for the imaging of heterogeneous tumor cells.

    Science.gov (United States)

    Chavva, Suhash Reddy; Viraka Nellore, Bhanu Priya; Pramanik, Avijit; Sinha, Sudarson Sekhar; Jones, Stacy; Ray, Paresh Chandra

    2016-07-14

    Tumor heterogeneity is one of the biggest challenges in cancer treatment and diagnosis. A multicolor optical ruler is essential to address the heterogeneous tumor cell complexity. Driven by this need, the current article reports the design of a multicolor long range nanoscopic ruler for screening tumor heterogeneity by accurately identifying epithelial cells and cancer stem cells (CSCs) simultaneously. A nanoscopic surface energy transfer (NSET) ruler has been developed using blue fluorescence polymer dots (PDs) and red fluorescence gold cluster dots (GCDs) as multicolor fluorescence donor and plasmonic gold nanoparticle (GNP) acts as an excellent acceptor. Reported experimental results demonstrated that the multicolor nanoscopic ruler's working window is above 35 nm distances, which is more than three times farther than that of Förster resonance energy transfer (FRET) distance limit. Theoretical modeling using Förster dipole-dipole coupling and dipole to nanoparticle surface energy transfer have been used to discuss the possible mechanism for multicolor nanoscopic ruler's long-range capability. Using RNA aptamers that are specific for the target cancer cells, experimental data demonstrate that the nanoscopic ruler can be used for screening epithelial and CSCs simultaneously from a whole blood sample with a detection capability of 10 cells per mL. Experimental data show that the nanoscopic ruler can distinguish targeted cells from non-targeted cells. PMID:27380815

  20. A cellular model reflecting the phenotypic heterogeneity of mutant HRAS driven squamous cell carcinoma.

    Science.gov (United States)

    Cantariño, Neus; Fernández-Figueras, M Teresa; Valero, Vanesa; Musulén, Eva; Malinverni, Roberto; Granada, Isabel; Goldie, Stephen J; Martín-Caballero, Juan; Douet, Julien; Forcales, Sonia-Vanina; Buschbeck, Marcus

    2016-09-01

    Squamous cell carcinomas have a range of histopathological manifestations. The parameters that determine this clinically observed heterogeneity are not fully understood. Here, we report the generation of a cell culture model that reflects part of this heterogeneity. We have used the catalytic subunit of human telomerase hTERT and large T to immortalize primary UV-unexposed keratinocytes. Then, mutant HRAS G12V has been introduced to transform these immortal keratinocytes. When injected into immunosuppressed mice, transformed cells grew as xenografts with distinct histopathological characteristics. We observed three major tissue architectures: solid, sarcomatoid and cystic growth types, which were primarily composed of pleomorphic and basaloid cells but in some cases displayed focal apocrine differentiation. We demonstrate that the cells generated represent different stages of skin cancerogenesis and as such can be used to identify novel tumor-promoting alterations such as the overexpression of the PADI2 oncogene in solid-type SCC. Importantly, the cultured cells maintain the characteristics from the xenograft they were derived from while being amenable to manipulation and analysis. The availability of cell lines representing different clinical manifestations opens a new tool to study the stochastic and deterministic factors that cause case-to-case heterogeneity despite departing from the same set of oncogenes and the same genetic background. PMID:27074337

  1. Targeting population heterogeneity in Saccharomyces cerevisiae batch fermentation for optimal cell factories

    DEFF Research Database (Denmark)

    Heins, Anna-Lena; Lencastre Fernandes, Rita; Lundin, L.; Carlqvist, Magnus; Sörensen, S.; Gernaey, Krist; Eliasson Lantz, Anna

    )). Significant gradients of e.g. dissolved oxygen, substrates, and pH are typically observed in many industrial scale fermentation processes. Consequently, the microbial cells experience rapid changes in environmental conditions as they circulate throughout the reactor, which might pose stress on the cells and...... constructed which enabled us to perform single cell level analysis, and thereby created the possibility to map population heterogeneity. A factorial design with pH, glucose concentration and oxygen level was performed in batch cultivations using the growth reporter strains to evaluate the effect of those...... environmental factors on heterogeneity level and amount of living cells. A highly dynamic behavior with regard to subpopulation distribution during the different growth stages was seen for the batch cultivations. Moreover, it could be demonstrated that the glucose concentration had a clear influence on the...

  2. Spatial and temporal heterogeneities of Aedes albopictus density in La Reunion Island: rise and weakness of entomological indices.

    Directory of Open Access Journals (Sweden)

    Sebastien Boyer

    Full Text Available Following the 2006 Chikungunya disease in La Reunion, questions were raised concerning the monitoring survey of Aedes albopictus populations and the entomological indexes used to evaluate population abundance. The objectives of the present study were to determine reliable productivity indexes using a quantitative method to improve entomological surveys and mosquito control measures on Aedes albopictus. Between 2007 and 2011, 4 intervention districts, 24 cities, 990 areas and over 850,000 houses were used to fulfil those objectives. Four indexes including the classical Stegomyia index (House Index, Container Index, Breteau Index plus an Infested Receptacle Index were studied in order to determine whether temporal (year, month, week and/or spatial (districts, cities, areas heterogeneities existed. Temporal variations have been observed with an increase of Ae. albopictus population density over the years, and a seasonality effect with a highest population during the hot and wet season. Spatial clustering was observed at several scales with an important autocorrelation at the area scale. Moreover, the combination among these results and the breeding site productivity obtained during these 5 years allowed us to propose recommendations to monitor Aedes albopictus by eliminating not the most finding sites but the most productive ones. As the other strategies failed in La Reunion, this new approach should should work better.

  3. Genetic Heterogeneity and Clonal Evolution of Tumor Cells and their Impact on Precision Cancer Medicine

    OpenAIRE

    Sabaawy, Hatem E.

    2013-01-01

    The efficacy of targeted therapies in leukemias and solid tumors depends upon the accurate detection and sustained targeting of initial and evolving driver mutations and/or aberrations in cancer cells. Tumor clonal evolution of the diverse populations of cancer cells during cancer progression contributes to the longitudinal variations of clonal, morphological, anatomical, and molecular heterogeneity of tumors. Moreover, drug-resistant subclones present at initiation of therapy or emerging as ...

  4. Anorexia Reduces GFAP+ Cell Density in the Rat Hippocampus

    Science.gov (United States)

    Labrada-Moncada, Francisco Emmanuel; Varman, Durairaj Ragu; Krüger, Janina; Morales, Teresa; Miledi, Ricardo; Martínez-Torres, Ataúlfo

    2016-01-01

    Anorexia nervosa is an eating disorder observed primarily in young women. The neurobiology of the disorder is unknown but recently magnetic resonance imaging showed a volume reduction of the hippocampus in anorexic patients. Dehydration-induced anorexia (DIA) is a murine model that mimics core features of this disorder, including severe weight loss due to voluntary reduction in food intake. The energy supply to the brain is mediated by astrocytes, but whether their density is compromised by anorexia is unknown. Thus, the aim of this study was to estimate GFAP+ cell density in the main regions of the hippocampus (CA1, CA2, CA3, and dentate gyrus) in the DIA model. Our results showed that GFAP+ cell density was significantly reduced (~20%) in all regions of the hippocampus, except in CA1. Interestingly, DIA significantly reduced the GFAP+ cells/nuclei ratio in CA2 (−23%) and dentate gyrus (−48%). The reduction of GFAP+ cell density was in agreement with a lower expression of GFAP protein. Additionally, anorexia increased the expression of the intermediate filaments vimentin and nestin. Accordingly, anorexia increased the number of reactive astrocytes in CA2 and dentate gyrus more than twofold. We conclude that anorexia reduces the hippocampal GFAP+ cell density and increases vimentin and nestin expression.

  5. Anorexia Reduces GFAP+ Cell Density in the Rat Hippocampus.

    Science.gov (United States)

    Reyes-Haro, Daniel; Labrada-Moncada, Francisco Emmanuel; Varman, Durairaj Ragu; Krüger, Janina; Morales, Teresa; Miledi, Ricardo; Martínez-Torres, Ataúlfo

    2016-01-01

    Anorexia nervosa is an eating disorder observed primarily in young women. The neurobiology of the disorder is unknown but recently magnetic resonance imaging showed a volume reduction of the hippocampus in anorexic patients. Dehydration-induced anorexia (DIA) is a murine model that mimics core features of this disorder, including severe weight loss due to voluntary reduction in food intake. The energy supply to the brain is mediated by astrocytes, but whether their density is compromised by anorexia is unknown. Thus, the aim of this study was to estimate GFAP+ cell density in the main regions of the hippocampus (CA1, CA2, CA3, and dentate gyrus) in the DIA model. Our results showed that GFAP+ cell density was significantly reduced (~20%) in all regions of the hippocampus, except in CA1. Interestingly, DIA significantly reduced the GFAP+ cells/nuclei ratio in CA2 (-23%) and dentate gyrus (-48%). The reduction of GFAP+ cell density was in agreement with a lower expression of GFAP protein. Additionally, anorexia increased the expression of the intermediate filaments vimentin and nestin. Accordingly, anorexia increased the number of reactive astrocytes in CA2 and dentate gyrus more than twofold. We conclude that anorexia reduces the hippocampal GFAP+ cell density and increases vimentin and nestin expression. PMID:27579183

  6. Extensive cell heterogeneity during persistent infection with foot-and-mouth disease virus.

    OpenAIRE

    de la Torre, J C; Martínez-Salas, E; J. Díez; Domingo, E

    1989-01-01

    Coevolution of viruses and the host cells occurred in BHK-21 cell cultures persistently infected with foot-and-mouth disease virus (FMDV) (J. C. de la Torre, E. Martínez-Salas, J. Diez, A. Villaverde, F. Gebauer, E. Rocha, M. Dávila, and E. Domingo, J. Virol. 62:2050-2058, 1988). In the present report we provide evidence of an extreme phenotypic heterogeneity of the cells, which was generated in the course of persistence. A total of 248 stable cell clones isolated from FMDV carrier cultures a...

  7. Sparse PCA corrects for cell type heterogeneity in epigenome-wide association studies.

    Science.gov (United States)

    Rahmani, Elior; Zaitlen, Noah; Baran, Yael; Eng, Celeste; Hu, Donglei; Galanter, Joshua; Oh, Sam; Burchard, Esteban G; Eskin, Eleazar; Zou, James; Halperin, Eran

    2016-05-01

    In epigenome-wide association studies (EWAS), different methylation profiles of distinct cell types may lead to false discoveries. We introduce ReFACTor, a method based on principal component analysis (PCA) and designed for the correction of cell type heterogeneity in EWAS. ReFACTor does not require knowledge of cell counts, and it provides improved estimates of cell type composition, resulting in improved power and control for false positives in EWAS. Corresponding software is available at http://www.cs.tau.ac.il/~heran/cozygene/software/refactor.html. PMID:27018579

  8. High power density yeast catalyzed microbial fuel cells

    Science.gov (United States)

    Ganguli, Rahul

    Microbial fuel cells leverage whole cell biocatalysis to convert the energy stored in energy-rich renewable biomolecules such as sugar, directly to electrical energy at high efficiencies. Advantages of the process include ambient temperature operation, operation in natural streams such as wastewater without the need to clean electrodes, minimal balance-of-plant requirements compared to conventional fuel cells, and environmentally friendly operation. These make the technology very attractive as portable power sources and waste-to-energy converters. The principal problem facing the technology is the low power densities compared to other conventional portable power sources such as batteries and traditional fuel cells. In this work we examined the yeast catalyzed microbial fuel cell and developed methods to increase the power density from such fuel cells. A combination of cyclic voltammetry and optical absorption measurements were used to establish significant adsorption of electron mediators by the microbes. Mediator adsorption was demonstrated to be an important limitation in achieving high power densities in yeast-catalyzed microbial fuel cells. Specifically, the power densities are low for the length of time mediator adsorption continues to occur. Once the mediator adsorption stops, the power densities increase. Rotating disk chronoamperometry was used to extract reaction rate information, and a simple kinetic expression was developed for the current observed in the anodic half-cell. Since the rate expression showed that the current was directly related to microbe concentration close to the electrode, methods to increase cell mass attached to the anode was investigated. Electrically biased electrodes were demonstrated to develop biofilm-like layers of the Baker's yeast with a high concentration of cells directly connected to the electrode. The increased cell mass did increase the power density 2 times compared to a non biofilm fuel cell, but the power density

  9. Solid Oxide Electrolysis Cells: Degradation at High Current Densities

    DEFF Research Database (Denmark)

    Knibbe, Ruth; Traulsen, Marie Lund; Hauch, Anne; Ebbesen, Sune; Mogensen, Mogens Bjerg

    2010-01-01

    The degradation of Ni/yttria-stabilized zirconia (YSZ)-based solid oxide electrolysis cells operated at high current densities was studied. The degradation was examined at 850°C, at current densities of −1.0, −1.5, and −2.0 A/cm2, with a 50:50 (H2O:H2) gas supplied to the Ni/YSZ hydrogen electrode...

  10. Detection and quantification of subtle changes in red blood cell density using a cell phone.

    Science.gov (United States)

    Felton, Edward J; Velasquez, Anthony; Lu, Shulin; Murphy, Ryann O; ElKhal, Abdala; Mazor, Ofer; Gorelik, Pavel; Sharda, Anish; Ghiran, Ionita C

    2016-08-16

    Magnetic levitation has emerged as a technique that offers the ability to differentiate between cells with different densities. We have developed a magnetic levitation system for this purpose that distinguishes not only different cell types but also density differences in cells of the same type. This small-scale system suspends cells in a paramagnetic medium in a capillary placed between two rare earth magnets, and cells levitate to an equilibrium position determined solely by their density. Uniform reference beads of known density are used in conjunction with the cells as a means to quantify their levitation positions. In one implementation images of the levitating cells are acquired with a microscope, but here we also introduce a cell phone-based device that integrates the magnets, capillary, and a lens into a compact and portable unit that acquires images with the phone's camera. To demonstrate the effectiveness of magnetic levitation in cell density analysis we carried out levitation experiments using red blood cells with artificially altered densities, and also levitated those from donors. We observed that we can distinguish red blood cells of an anemic donor from those that are healthy. Since a plethora of disease states are characterized by changes in cell density magnetic cell levitation promises to be an effective tool in identifying and analyzing pathologic states. Furthermore, the low cost, portability, and ease of use of the cell phone-based system may potentially lead to its deployment in low-resource environments. PMID:27431921

  11. CTen: a web-based platform for identifying enriched cell types from heterogeneous microarray data

    Directory of Open Access Journals (Sweden)

    Shoemaker Jason E

    2012-09-01

    Full Text Available Abstract Background Interpreting in vivo sampled microarray data is often complicated by changes in the cell population demographics. To put gene expression into its proper biological context, it is necessary to distinguish differential gene transcription from artificial gene expression induced by changes in the cellular demographics. Results CTen (cell type enrichment is a web-based analytical tool which uses our highly expressed, cell specific (HECS gene database to identify enriched cell types in heterogeneous microarray data. The web interface is designed for differential expression and gene clustering studies, and the enrichment results are presented as heatmaps or downloadable text files. Conclusions In this work, we use an independent, cell-specific gene expression data set to assess CTen's performance in accurately identifying the appropriate cell type and provide insight into the suggested level of enrichment to optimally minimize the number of false discoveries. We show that CTen, when applied to microarray data developed from infected lung tissue, can correctly identify the cell signatures of key lymphocytes in a highly heterogeneous environment and compare its performance to another popular bioinformatics tool. Furthermore, we discuss the strong implications cell type enrichment has in the design of effective microarray workflow strategies and show that, by combining CTen with gene expression clustering, we may be able to determine the relative changes in the number of key cell types. CTen is available at http://www.influenza-x.org/~jshoemaker/cten/

  12. Heterogeneous glioblastoma cell cross-talk promotes phenotype alterations and enhanced drug resistance.

    Science.gov (United States)

    Motaln, Helena; Koren, Ana; Gruden, Kristina; Ramšak, Živa; Schichor, Christian; Lah, Tamara T

    2015-12-01

    Glioblastoma multiforme is the most lethal of brain cancer, and it comprises a heterogeneous mixture of functionally distinct cancer cells that affect tumor progression. We examined the U87, U251, and U373 malignant cell lines as in vitro models to determine the impact of cellular cross-talk on their phenotypic alterations in co-cultures. These cells were also studied at the transcriptome level, to define the mechanisms of their observed mutually affected genomic stability, proliferation, invasion and resistance to temozolomide. This is the first direct demonstration of the neural and mesenchymal molecular fingerprints of U87 and U373 cells, respectively. U87-cell conditioned medium lowered the genomic stability of U373 (U251) cells, without affecting cell proliferation. In contrast, upon exposure of U87 cells to U373 (U251) conditioned medium, U87 cells showed increased genomic stability, decreased proliferation rates and increased invasion, due to a plethora of produced cytokines identified in the co-culture media. This cross talk altered the expression 264 genes in U87 cells that are associated with proliferation, inflammation, migration, and adhesion, and 221 genes in U373 cells that are associated with apoptosis, the cell cycle, cell differentiation and migration. Indirect and direct co-culturing of U87 and U373 cells showed mutually opposite effects on temozolomide resistance. In conclusion, definition of transcriptional alterations of distinct glioblastoma cells upon co-culturing provides better understanding of the mechanisms of glioblastoma heterogeneity, which will provide the basis for more informed glioma treatment in the future. PMID:26517510

  13. Assessment of interpatient heterogeneity in tumor radiosensitivity for nonsmall cell lung cancer using tumor-volume variation data

    Energy Technology Data Exchange (ETDEWEB)

    Chvetsov, Alexei V., E-mail: chvetsov2@gmail.com; Schwartz, Jeffrey L.; Mayr, Nina [Department of Radiation Oncology, University of Washington, 1959 NE Pacific Street, Seattle, Washington 98195-6043 (United States); Yartsev, Slav [London Regional Cancer Program, London Health Sciences Centre, 790 Commissioners Road East, London, Ontario 46A 4L6 (Canada)

    2014-06-15

    Purpose: In our previous work, the authors showed that a distribution of cell surviving fractionsS{sub 2} in a heterogeneous group of patients could be derived from tumor-volume variation curves during radiotherapy for head and neck cancer. In this research study, the authors show that this algorithm can be applied to other tumors, specifically in nonsmall cell lung cancer. This new application includes larger patient volumes and includes comparison of data sets obtained at independent institutions. Methods: Our analysis was based on two data sets of tumor-volume variation curves for heterogeneous groups of 17 patients treated for nonsmall cell lung cancer with conventional dose fractionation. The data sets were obtained previously at two independent institutions by using megavoltage computed tomography. Statistical distributions of cell surviving fractionsS{sub 2} and clearance half-lives of lethally damaged cells T{sub 1/2} have been reconstructed in each patient group by using a version of the two-level cell population model of tumor response and a simulated annealing algorithm. The reconstructed statistical distributions of the cell surviving fractions have been compared to the distributions measured using predictive assays in vitro. Results: Nonsmall cell lung cancer presents certain difficulties for modeling surviving fractions using tumor-volume variation curves because of relatively large fractional hypoxic volume, low gradient of tumor-volume response, and possible uncertainties due to breathing motion. Despite these difficulties, cell surviving fractionsS{sub 2} for nonsmall cell lung cancer derived from tumor-volume variation measured at different institutions have similar probability density functions (PDFs) with mean values of 0.30 and 0.43 and standard deviations of 0.13 and 0.18, respectively. The PDFs for cell surviving fractions S{sub 2} reconstructed from tumor volume variation agree with the PDF measured in vitro. Conclusions: The data obtained

  14. Functional malignant cell heterogeneity in pancreatic neuroendocrine tumors revealed by targeting of PDGF-DD

    Science.gov (United States)

    Cortez, Eliane; Gladh, Hanna; Braun, Sebastian; Bocci, Matteo; Cordero, Eugenia; Björkström, Niklas K.; Miyazaki, Hideki; Michael, Iacovos P.; Eriksson, Ulf; Folestad, Erika; Pietras, Kristian

    2016-01-01

    Intratumoral heterogeneity is an inherent feature of most human cancers and has profound implications for cancer therapy. As a result, there is an emergent need to explore previously unmapped mechanisms regulating distinct subpopulations of tumor cells and to understand their contribution to tumor progression and treatment response. Aberrant platelet-derived growth factor receptor beta (PDGFRβ) signaling in cancer has motivated the development of several antagonists currently in clinical use, including imatinib, sunitinib, and sorafenib. The discovery of a novel ligand for PDGFRβ, platelet-derived growth factor (PDGF)-DD, opened the possibility of a previously unidentified signaling pathway involved in tumor development. However, the precise function of PDGF-DD in tumor growth and invasion remains elusive. Here, making use of a newly generated Pdgfd knockout mouse, we reveal a functionally important malignant cell heterogeneity modulated by PDGF-DD signaling in pancreatic neuroendocrine tumors (PanNET). Our analyses demonstrate that tumor growth was delayed in the absence of signaling by PDGF-DD. Surprisingly, ablation of PDGF-DD did not affect the vasculature or stroma of PanNET; instead, we found that PDGF-DD stimulated bulk tumor cell proliferation by induction of paracrine mitogenic signaling between heterogeneous malignant cell clones, some of which expressed PDGFRβ. The presence of a subclonal population of tumor cells characterized by PDGFRβ expression was further validated in a cohort of human PanNET. In conclusion, we demonstrate a previously unrecognized heterogeneity in PanNET characterized by signaling through the PDGF-DD/PDGFRβ axis. PMID:26831065

  15. Heterogeneity of leukemia-initiating capacity of chronic myelogenous leukemia stem cells.

    Science.gov (United States)

    Zhang, Bin; Li, Ling; Ho, Yinwei; Li, Min; Marcucci, Guido; Tong, Wei; Bhatia, Ravi

    2016-03-01

    Chronic myelogenous leukemia (CML) results from transformation of a long-term hematopoietic stem cell (LTHSC) by expression of the BCR-ABL fusion gene. However, BCR-ABL-expressing LTHSCs are heterogeneous in their capacity as leukemic stem cells (LSCs). Although discrepancies in proliferative, self-renewal, and differentiation properties of normal LTHSCs are being increasingly recognized, the mechanisms underlying heterogeneity of leukemic LTHSCs are poorly understood. Using a CML mouse model, we identified gene expression differences between leukemic and nonleukemic LTHSCs. Expression of the thrombopoietin (THPO) receptor MPL was elevated in leukemic LTHSC populations. Compared with LTHSCs with low MPL expression, LTHSCs with high MPL expression showed enhanced JAK/STAT signaling and proliferation in response to THPO in vitro and increased leukemogenic capacity in vivo. Although both G0 and S phase subpopulations were increased in LTHSCs with high MPL expression, LSC capacity was restricted to quiescent cells. Inhibition of MPL expression in CML LTHSCs reduced THPO-induced JAK/STAT signaling and leukemogenic potential. These same phenotypes were also present in LTHSCs from patients with CML, and patient LTHSCs with high MPL expression had reduced sensitivity to BCR-ABL tyrosine kinase inhibitor treatment but increased sensitivity to JAK inhibitors. Together, our studies identify MPL expression levels as a key determinant of heterogeneous leukemia-initiating capacity and drug sensitivity of CML LTHSCs and suggest that high MPL-expressing CML stem cells are potential targets for therapy. PMID:26878174

  16. Preface of the "Symposium on Mathematical Models and Methods to investigate Heterogeneity in Cell and Cell Population Biology"

    Science.gov (United States)

    Clairambault, Jean

    2016-06-01

    This session investigates hot topics related to mathematical representations of cell and cell population dynamics in biology and medicine, in particular, but not only, with applications to cancer. Methods in mathematical modelling and analysis, and in statistical inference using single-cell and cell population data, should contribute to focus this session on heterogeneity in cell populations. Among other methods are proposed: a) Intracellular protein dynamics and gene regulatory networks using ordinary/partial/delay differential equations (ODEs, PDEs, DDEs); b) Representation of cell population dynamics using agent-based models (ABMs) and/or PDEs; c) Hybrid models and multiscale models to integrate single-cell dynamics into cell population behaviour; d) Structured cell population dynamics and asymptotic evolution w.r.t. relevant traits; e) Heterogeneity in cancer cell populations: origin, evolution, phylogeny and methods of reconstruction; f) Drug resistance as an evolutionary phenotype: predicting and overcoming it in therapeutics; g) Theoretical therapeutic optimisation of combined drug treatments in cancer cell populations and in populations of other organisms, such as bacteria.

  17. Deformable L-shaped microwell array for trapping pairs of heterogeneous cells

    International Nuclear Information System (INIS)

    To study cell-to-cell interactions, there has been a continuous demand on developing microsystems for trapping pairs of two different cells in microwell arrays. Here, we propose an L-shaped microwell (L-microwell) array that relies on the elasticity of a polydimethylsiloxane (PDMS) substrate for trapping and pairing heterogeneous cells. We designed an L-microwell suitable for trapping single cell in each branch via stretching/releasing the PDMS substrate, and also performed 3D time-dependent diffusion simulations to visualize how cell-secreted molecules diffuse in the L-microwell and communicate with the partner cell. The computational results showed that the secreted molecule first contacted the partner cell after 35 min, and the secreted molecule fully covered the partner cell in 4 h (when referenced to 10% of the secreted molecular concentration). The molecules that diffused to the outside of the L-microwell were significantly diluted by the bulk solution, which prevented unwanted cellular communication between neighboring L-microwells. We produced over 5000 cell pairs in one 2.25 cm2 array with about 30 000 L-microwells. The proposed L-microwell array offers a versatile and convenient cell pairing method to investigate cell-to-cell interactions in, for example, cell fusion, immune reactions, and cancer metastasis. (paper)

  18. Embryonic stem cell as nuclear donor could promote in vitro development of the heterogeneous reconstructed embryo

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The nucleus of a somatic cell could be dedifferentiated and reprogrammed in an enucleated heterogeneous oocyte. Some reconstructed oocytes could develop into blastocysts in vitro, and a few could develop into term normally after transferred into foster mothers, but most of cloning embryos fail to develop to term. In order to evaluate the efficacy of embryonic stem cell as nucleus donor in interspecific animal cloning, we reconstructed enucleated rabbit oocytes with nuclei from mouse ES cells, and analyzed the developmental ability of reconstructed embryos in vitro. Two kinds of fibroblast cells were used as donor control, one derived from ear skin of an adult Kunming albino mouse, and the other derived from a mouse fetus. Three types of cells were transferred into perivitelline space under zona pellucida of rabbit oocytes respectively. The reconstructed oocytes were fused and activated by electric pulses, and cultured in vitro. The developmental rate of reconstructed oocytes derived from embryonic stem cells was 16.1%, which was significantly higher than that of both the adult mouse fibroblast cells (0%-3.1%, P < 0.05) and fetus mouse fibroblast cells (2.1%-3.7%, P < 0.05). Chromosome analysis confirmed that blastocyst cells were derived from ES donor cell. These observations show that reprogramming is easier in interspecific embryos reconstructed with ES cells than that reconstructed with somatic cells, and that ES cells have the higher ability to direct the reconstructed embryos development normally than fibroblast cells.

  19. A random graph model of density thresholds in swarming cells.

    Science.gov (United States)

    Jena, Siddhartha G

    2016-03-01

    Swarming behaviour is a type of bacterial motility that has been found to be dependent on reaching a local density threshold of cells. With this in mind, the process through which cell-to-cell interactions develop and how an assembly of cells reaches collective motility becomes increasingly important to understand. Additionally, populations of cells and organisms have been modelled through graphs to draw insightful conclusions about population dynamics on a spatial level. In the present study, we make use of analogous random graph structures to model the formation of large chain subgraphs, representing interactions between multiple cells, as a random graph Markov process. Using numerical simulations and analytical results on how quickly paths of certain lengths are reached in a random graph process, metrics for intercellular interaction dynamics at the swarm layer that may be experimentally evaluated are proposed. PMID:26893102

  20. High heterogeneity of plasma membrane microfluidity in multidrug-resistant cancer cells

    Science.gov (United States)

    Boutin, Céline; Roche, Yann; Millot, Christine; Deturche, Régis; Royer, Pascal; Manfait, Michel; Plain, Jérôme; Jeannesson, Pierre; Millot, Jean-Marc; Jaffiol, Rodolphe

    2009-05-01

    Diffusion-time distribution analysis (DDA) has been used to explore the plasma membrane fluidity of multidrug-resistant cancer cells (LR73 carcinoma cells) and also to characterize the influence of various membrane agents present in the extracellular medium. DDA is a recent single-molecule technique, based on fluorescence correlation spectroscopy (FCS), well suited to retrieve local organization of cell membrane. The method was conducted on a large number of living cells, which enabled us to get a detailed overview of plasma membrane microviscosity, and plasma membrane micro-organization, between the cells of the same line. Thus, we clearly reveal the higher heterogeneity of plasma membrane in multidrug-resistant cancer cells in comparison with the nonresistant ones (denoted sensitive cells). We also display distinct modifications related to a membrane fluidity modulator, benzyl alcohol, and two revertants of multidrug resistance, verapamil and cyclosporin-A. A relation between the distribution of the diffusion-time values and the modification of membrane lateral heterogeneities is proposed.

  1. Anti-cancer efficacy of nonthermal plasma dissolved in a liquid, liquid plasma in heterogeneous cancer cells

    OpenAIRE

    Ngoc Hoan Nguyen; Hyung Jun Park; Sang Sik Yang; Kyeong Sook Choi; Jong-Soo Lee

    2016-01-01

    The therapeutic potential of nonthermal plasma for cancer treatment has been reported recently. The heterogeneity of cancer cells need to be addressed to design effective anticancer treatments. Here, we show that treatment with nonthermal atmospheric-pressure plasma dissolved in a liquid (liquid plasma) induces oxidative stress in heterogeneous populations of cancer cells and ultimately kills these cells via apoptosis, regardless of genetic status, e.g., mutations in p53 and other DNA-damage-...

  2. Hair cell heterogeneity and ultrasonic hearing: recent advances in understanding fish hearing.

    OpenAIRE

    Popper, A N

    2000-01-01

    The past decade has seen a wealth of new data on the auditory capabilities and mechanisms of fishes. We now have a significantly better appreciation of the structure and function of the auditory system in fishes with regard to their peripheral and central anatomy, physiology, behaviour, sound source localization and hearing capabilities. This paper deals with two of the newest of these findings, hair cell heterogeneity and the detection of ultrasound. As a result of this recent work, we now k...

  3. The New Frontier in RAN Heterogeneity: Multi-tier Drone-Cells

    OpenAIRE

    Bor-Yaliniz, Irem; Yanikomeroglu, Halim

    2016-01-01

    In cellular networks, the locations of the radio access network (RAN) elements are determined mainly based on the long-term traffic behaviour. However, when the random and hard-to-predict spatio-temporal distribution of the traffic (load,demand) does not fully match the fixed locations of the RAN elements (supply), some performance degradation becomes inevitable. The concept of multi-tier cells (heterogeneous networks, HetNets) has been introduced in 4G networks to alleviate this mismatch. Ho...

  4. Microwell-Based Live Cell Imaging of NK Cell Dynamics to Assess Heterogeneity in Motility and Cytotoxic Response.

    Science.gov (United States)

    Vanherberghen, Bruno; Frisk, Thomas; Forslund, Elin; Olofsson, Per E; Guldevall, Karolin; Önfelt, Björn

    2016-01-01

    NK cell heterogeneity has primarily been studied either on the population level, measuring average responses, or on the single cell level by flow cytometry, providing static snapshots. These approaches have certain drawbacks, not enabling dynamic observations of single cells over extended periods of time. One of the primary limitations of single cell imaging has been throughput; it has been challenging to collect data for many cells due to their dynamic nature and migrating out of the field of view. Spatially confining cells combined with automated fluorescence microscopy enables the simultaneous monitoring of many NK cells in parallel for extended periods of time (>12 h). Such an approach allows us to dissect how the sum of individual NK cell responses translates to the global average response typically observed. PMID:27177659

  5. Measuring density and compressibility of white blood cells and prostate cancer cells by microchannel acoustophoresis

    DEFF Research Database (Denmark)

    Barnkob, Rune; Augustsson, Per; Magnusson, Cecilia; Lilja, Hans; Laurell, Thomas; Bruus, Henrik

    determine the density and compressibility of individual cells enables the prediction and alteration of the separation outcome for a given cell mixture. We apply the method on white blood cells (WBCs) and DU145 prostate cancer cells (DUCs) aiming to improve isolation of circulating tumor cells from blood, an......We present a novel method for the determination of density and compressibility of individual particles and cells undergoing microchannel acoustophoresis in an arbitrary 2D acoustic field. Our method is a critical advancement within acoustophoretic separation of biological cells, as the ability to...... emerging tool in the monitoring and characterizing of metastatic cancer....

  6. Androgen receptor heterogeneity and phosphorylation in human LNCaP cells

    International Nuclear Information System (INIS)

    Androgen receptor heterogeneity and phosphorylation were studied in the human LNCaP cell line. Fluorography after photoaffinity labeling as well as immunoblotting with a specific polyclonal antibody revealed that the human androgen receptor migrated as a closely spaced 110 kD doublet on SDS-polyacrylamide gels. A time-dependent change in the ratio between the two isoforms was not observed after R1881 treatment of intact cells. In nuclear extracts of LNCaP cells that were incubated with [32P]orthophosphate in the presence of 10 nM R1881, a 110 kD phosphorylated protein was demonstrated after immunopurification using a monoclonal antibody against the human androgen receptor. Only a very small amount of this phosphoprotein was detected in the nuclear fraction from cells not treated with R1881. These results indicate that the human androgen receptor in LNCaP cells can be phosphorylated

  7. Nanofiber density determines endothelial cell behavior on hydrogel matrix

    International Nuclear Information System (INIS)

    When cultured under static conditions, bacterial cellulose pellicles, by the nature of the polymer synthesis that involves molecular oxygen, are characterized by two distinct surface sides. The upper surface is denser in fibers (entangled) than the lower surface that shows greater surface porosity. Human umbilical vein endothelial cells (HUVECs) were used to exploit how the microarchitecture (i.e., surface porosity, fiber network structure, surface topology, and fiber density) of bacterial cellulose pellicle surfaces influence cell–biomaterial interaction and therefore cell behavior. Adhesion, cell ingrowth, proliferation, viability and cell death mechanisms were evaluated on the two pellicle surface sides. Cell behavior, including secondary necrosis, is influenced only by the microarchitecture of the surface, since the biomaterial is extremely pure (constituted of cellulose and water only). Cell–cellulose fiber interaction is the determinant signal in the cell–biomaterial responses, isolated from other frequently present interferences such as protein and other chemical traces usually present in cell culture matrices. Our results suggest that microarchitecture of hydrogel materials might determine the performance of biomedical products, such as bacterial cellulose tissue engineering constructs (BCTECs). - Highlights: • Topography of BC pellicle is relevant to determine endothelial cells' fate. • Cell–biomaterial response is affected by the topography of BC-pellicle surface. • Endothelial cells exhibit different behavior depending on the BC topography. • Apoptosis and necrosis of endothelial cells were affected by the BC topography

  8. Nanofiber density determines endothelial cell behavior on hydrogel matrix

    Energy Technology Data Exchange (ETDEWEB)

    Berti, Fernanda V., E-mail: fernanda@intelab.ufsc.br [Department of Chemical and Food Engineering, Federal University of Santa Catarina, 88040-900 Florianópolis, SC (Brazil); Rambo, Carlos R. [Department of Electrical Engineering, Federal University of Santa Catarina, 88040-900 Florianópolis, SC (Brazil); Dias, Paulo F. [Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina, 88040-900 Florianópolis, SC (Brazil); Porto, Luismar M. [Department of Chemical and Food Engineering, Federal University of Santa Catarina, 88040-900 Florianópolis, SC (Brazil)

    2013-12-01

    When cultured under static conditions, bacterial cellulose pellicles, by the nature of the polymer synthesis that involves molecular oxygen, are characterized by two distinct surface sides. The upper surface is denser in fibers (entangled) than the lower surface that shows greater surface porosity. Human umbilical vein endothelial cells (HUVECs) were used to exploit how the microarchitecture (i.e., surface porosity, fiber network structure, surface topology, and fiber density) of bacterial cellulose pellicle surfaces influence cell–biomaterial interaction and therefore cell behavior. Adhesion, cell ingrowth, proliferation, viability and cell death mechanisms were evaluated on the two pellicle surface sides. Cell behavior, including secondary necrosis, is influenced only by the microarchitecture of the surface, since the biomaterial is extremely pure (constituted of cellulose and water only). Cell–cellulose fiber interaction is the determinant signal in the cell–biomaterial responses, isolated from other frequently present interferences such as protein and other chemical traces usually present in cell culture matrices. Our results suggest that microarchitecture of hydrogel materials might determine the performance of biomedical products, such as bacterial cellulose tissue engineering constructs (BCTECs). - Highlights: • Topography of BC pellicle is relevant to determine endothelial cells' fate. • Cell–biomaterial response is affected by the topography of BC-pellicle surface. • Endothelial cells exhibit different behavior depending on the BC topography. • Apoptosis and necrosis of endothelial cells were affected by the BC topography.

  9. Licensing by Inflammatory Cytokines Abolishes Heterogeneity of Immunosuppressive Function of Mesenchymal Stem Cell Population.

    Science.gov (United States)

    Szabó, Enikő; Fajka-Boja, Roberta; Kriston-Pál, Éva; Hornung, Ákos; Makra, Ildikó; Kudlik, Gyöngyi; Uher, Ferenc; Katona, Róbert László; Monostori, Éva; Czibula, Ágnes

    2015-09-15

    When mesenchymal stem cells (MSCs) are used for therapy of immunological pathologies, they get into an inflammatory environment, altering the effectiveness of the treatment. To establish the impact of environmental inflammatory factors on MSCs' immunofunction in the mirror of intrinsic heterogeneity of mouse MSC population, individual MSC clones were generated and characterized. Adipogenic but not osteogenic differentiation and pro-angiogenic activity of five independent MSC cell lines were similar. Regarding osteogenic differentiation, clones MSC3 and MSC6 exhibited poorer capacity than MSC2, MSC4, and MSC5. To study the immunosuppressive heterogeneity, in vitro and in vivo experiments have been carried out using T-cell proliferation assay and delayed-type hypersensitivity (DTH) response, respectively. A remarkable difference was found between the clones in their ability to inhibit T-cell proliferation in the following order: MSC2≥MSC5>MSC4>MSC3 > MSC6. Nevertheless, the differences between the immunosuppressive activities of the individual clones disappeared on pretreatment of the cells with pro-inflammatory cytokines, a procedure called licensing. Stimulation of all clones with IFN-γ and TNF-α resulted in elevation of their inhibitory capability to a similar level. Nitric oxide (NO) and prostaglandin E2 (PGE2) were identified as major mediators of immunofunction of the MSC clones. The earlier findings were also supported by in vivo results. Without licensing, MSC2 inhibited DTH response, while MSC6 did not affect DTH response. In contrast, prestimulation of MSC6 with inflammatory cytokines resulted in strong suppression by this clone as well. Here, we have showed that MSC population is functionally heterogeneous in terms of immunosuppressive function; however, this variability is largely reduced under pro-inflammatory conditions. PMID:26153898

  10. Heterogeneous estrogen receptor expression in circulating tumor cells suggests diverse mechanisms of fulvestrant resistance.

    Science.gov (United States)

    Paoletti, Costanza; Larios, Jose M; Muñiz, Maria C; Aung, Kimberly; Cannell, Emily M; Darga, Elizabeth P; Kidwell, Kelley M; Thomas, Dafydd G; Tokudome, Nahomi; Brown, Martha E; Connelly, Mark C; Chianese, David A; Schott, Anne F; Henry, N Lynn; Rae, James M; Hayes, Daniel F

    2016-08-01

    Fulvestrant is a dose dependent selective estrogen receptor (ER) down-regulator (SERD) used in ER-positive metastatic breast cancer (MBC). Nearly all patients develop resistance. We performed molecular analysis of circulating tumor cells (CTC) to gain insight into fulvestrant resistance. Preclinical studies were performed with cultured breast cancer cells spiked into human blood and analyzed on the CellSearch(®) system. Clinical data are limited to a subset of patients with ER-positive MBC from a previously reported pilot trial whose disease was progressing on fulvestrant (N = 7) or aromatase inhibitors (AIs) (N = 10). CTCs were enumerated and phenotyped for ER and B-cell lymphoma (BCL2) using the CellSearch(®) CXC kit. In preclinical modeling, tamoxifen and AIs resulted in stabilized ER expression, whereas fulvestrant eliminated it. Five of seven patients progressing on fulvestrant had ≥5CTC/7.5 ml WB. Two of these five, treated with 500 mg/month fulvestrant, had no detectable CTC-expression of ER and BCL2 (an ER regulated gene). Three patients had heterogeneous CTC-ER and BCL2 expression indicating incomplete degradation of the ER target by fulvestrant. Two of these patients received 250 mg/month whereas the third patient received 500 mg/month fulvestrant. Her cancer harbored a mutation (Y537S) in the estrogen receptor alpha gene (ESR1). All seven ER positive patients progressing on AIs had heterogeneous CTC-ER expression. These results suggest heterogeneous mechanisms of resistance to fulvestrant, including insufficient dosage, ESR1 mutation, or conversion to dependence on non-ER pathways. CTC enumeration, phenotyping, and genotyping might identify patients who would benefit from fulvestrant dose escalation versus switching to alternative therapies. PMID:27178224

  11. Cell Selection Game for Densely-Deployed Sensor and Mobile Devices In 5G Networks Integrating Heterogeneous Cells and the Internet of Things

    OpenAIRE

    Lusheng Wang; Yamei Wang; Zhizhong Ding; Xiumin Wang

    2015-01-01

    With the rapid development of wireless networking technologies, the Internet of Things and heterogeneous cellular networks (HCNs) tend to be integrated to form a promising wireless network paradigm for 5G. Hyper-dense sensor and mobile devices will be deployed under the coverage of heterogeneous cells, so that each of them could freely select any available cell covering it and compete for resource with others selecting the same cell, forming a cell selection (CS) game between these devices. S...

  12. Minireview: Genetic basis of heterogeneity and severity in sickle cell disease.

    Science.gov (United States)

    Habara, Alawi; Steinberg, Martin H

    2016-04-01

    Sickle cell disease, a common single gene disorder, has a complex pathophysiology that at its root is initiated by the polymerization of deoxy sickle hemoglobin. Sickle vasoocclusion and hemolytic anemia drive the development of disease complications. In this review, we focus on the genetic modifiers of disease heterogeneity. The phenotypic heterogeneity of disease is only partially explained by genetic variability of fetal hemoglobin gene expression and co-inheritance of α thalassemia. Given the complexity of pathophysiology, many different definitions of severity are possible complicating a full understanding of its genetic foundation. The pathophysiological complexity and the interlocking nature of the biological processes underpinning disease severity are becoming better understood. Nevertheless, useful genetic signatures of severity, regardless of how this is defined, are insufficiently developed to be used for treatment decisions and for counseling. PMID:26936084

  13. Adhesion and receptor clustering stabilizes lateral heterogeneity in cell plasma membranes

    Science.gov (United States)

    Veatch, Sarah

    2013-03-01

    The thermodynamic properties of plasma membrane lipids play a vital role in many functions that initiate at the mammalian cell surface. Some functions are thought to occur, at least in part, because plasma membrane lipids have a tendency to separate into two distinct liquid phases, called liquid-ordered and liquid-disordered. We find that isolated cell plasma membranes are poised near a miscibility critical point separating these two liquid phases, and postulate that critical composition fluctuations provide the physical basis of functional membrane heterogeneity in intact cells. In this talk I will describe several possible mechanisms through which dynamic fluctuations can be stabilized in super-critical membranes, and will present some preliminary evidence suggesting that these structures can be visualized in intact cells using quantitative super-resolution fluorescence localization imaging.

  14. The biology of myeloid-derived suppressor cells: The blessing and the curse of morphological and functional heterogeneity

    OpenAIRE

    Youn, Je-in; Gabrilovich, Dmitry I.

    2010-01-01

    Myeloid-derived suppressor cells (MDSC) play an important role in the cellular network regulating immune responses in cancer, chronic infectious diseases, autoimmunity, and in other pathologic conditions. Morphological, phenotypic and functional heterogeneity is a hallmark of MDSC. This heterogeneity demonstrates the plasticity of this immune suppressive myeloid compartment, and shows how various tumors and infectious agents can have similar biological effects on myeloid cells despite the dif...

  15. Geometric effects in microfluidics on heterogeneous cell stress using an Eulerian-Lagrangian approach.

    Science.gov (United States)

    Warren, K M; Mpagazehe, J N; LeDuc, P R; Higgs, C F

    2016-02-01

    The response of individual cells at the micro-scale in cell mechanics is important in understanding how they are affected by changing environments. To control cell stresses, microfluidics can be implemented since there is tremendous control over the geometry of the devices. Designing microfluidic devices to induce and manipulate stress levels on biological cells can be aided by computational modeling approaches. Such approaches serve as an efficient precursor to fabricating various microfluidic geometries that induce predictable levels of stress on biological cells, based on their mechanical properties. Here, a three-dimensional, multiphase computational fluid dynamics (CFD) modeling approach was implemented for soft biological materials. The computational model incorporates the physics of the particle dynamics, fluid dynamics and solid mechanics, which allows us to study how stresses affect the cells. By using an Eulerian-Lagrangian approach to treat the fluid domain as a continuum in the microfluidics, we are conducting studies of the cells' movement and the stresses applied to the cell. As a result of our studies, we were able to determine that a channel with periodically alternating columns of obstacles was capable of stressing cells at the highest rate, and that microfluidic systems can be engineered to impose heterogenous cell stresses through geometric configuring. We found that when using controlled geometries of the microfluidics channels with staggered obstructions, we could increase the maximum cell stress by nearly 200 times over cells flowing through microfluidic channels with no obstructions. Incorporating computational modeling in the design of microfluidic configurations for controllable cell stressing could help in the design of microfludic devices for stressing cells such as cell homogenizers. PMID:26753780

  16. Label-free isolation and deposition of single bacterial cells from heterogeneous samples for clonal culturing.

    Science.gov (United States)

    Riba, J; Gleichmann, T; Zimmermann, S; Zengerle, R; Koltay, P

    2016-01-01

    The isolation and analysis of single prokaryotic cells down to 1 μm and less in size poses a special challenge and requires micro-engineered devices to handle volumes in the picoliter to nanoliter range. Here, an advanced Single-Cell Printer (SCP) was applied for automated and label-free isolation and deposition of bacterial cells encapsulated in 35 pl droplets by inkjet-like printing. To achieve this, dispenser chips to generate micro droplets have been fabricated with nozzles 20 μm in size. Further, the magnification of the optical system used for cell detection was increased. Redesign of the optical path allows for collision-free addressing of any flat substrate since no compartment protrudes below the nozzle of the dispenser chip anymore. The improved system allows for deterministic isolation of individual bacterial cells. A single-cell printing efficiency of 93% was obtained as shown by printing fluorescent labeled E. coli. A 96-well plate filled with growth medium is inoculated with single bacteria cells on average within about 8 min. Finally, individual bacterial cells from a heterogeneous sample of E. coli and E. faecalis were isolated for clonal culturing directly on agar plates in user-defined array geometry. PMID:27596612

  17. Functions of Heterogeneous Nuclear Ribonucleoproteins in Stem Cell Potency and Differentiation

    Directory of Open Access Journals (Sweden)

    Qishan Chen

    2013-01-01

    Full Text Available Stem cells possess huge importance in developmental biology, disease modelling, cell replacement therapy, and tissue engineering in regenerative medicine because they have the remarkable potential for self-renewal and to differentiate into almost all the cell types in the human body. Elucidation of molecular mechanisms regulating stem cell potency and differentiation is essential and critical for extensive application. Heterogeneous nuclear ribonucleoproteins (hnRNPs are modular proteins consisting of RNA-binding motifs and auxiliary domains characterized by extensive and divergent functions in nucleic acid metabolism. Multiple roles of hnRNPs in transcriptional and posttranscriptional regulation enable them to be effective gene expression regulators. More recent findings show that hnRNP proteins are crucial factors implicated in maintenance of stem cell self-renewal and pluripotency and cell differentiation. The hnRNPs interact with certain sequences in target gene promoter regions to initiate transcription. In addition, they recognize 3′UTR or 5′UTR of specific gene mRNA forming mRNP complex to regulate mRNA stability and translation. Both of these regulatory pathways lead to modulation of gene expression that is associated with stem cell proliferation, cell cycle control, pluripotency, and committed differentiation.

  18. Dynamic competition between transcription initiation and repression: Role of nonequilibrium steps in cell-to-cell heterogeneity.

    Science.gov (United States)

    Mitarai, Namiko; Semsey, Szabolcs; Sneppen, Kim

    2015-08-01

    Transcriptional repression may cause transcriptional noise by a competition between repressor and RNA polymerase binding. Although promoter activity is often governed by a single limiting step, we argue here that the size of the noise strongly depends on whether this step is the initial equilibrium binding or one of the subsequent unidirectional steps. Overall, we show that nonequilibrium steps of transcription initiation systematically increase the cell-to-cell heterogeneity in bacterial populations. In particular, this allows also weak promoters to give substantial transcriptional noise. PMID:26382435

  19. A transport method for treating three-dimensional lattices of heterogeneous cells

    International Nuclear Information System (INIS)

    A new ray-tracing method for the calculation of collision probabilities within arbitrary three-dimensional geometries has been developed. This method is used to discretize the neutron transport equation for the heterogenous rectangular cells containing zones of mixed cylindrical and rectangular geometry. For multicell applications, the interface current (IC) method provides the coupling between cells. The solution to the IC equations over multicell domains consisting of rectangular three-dimensional cells is improved by using an alternative direction implicit scheme with variational acceleration. Results indicate comparisons of this technique with SHETAN for simple geometries and the analysis of a three-dimensional extension of a two-dimensional 15 x 15 pressurized water reactor benchmark problem

  20. Heterogeneity of astrocytes: from development to injury - single cell gene expression.

    Directory of Open Access Journals (Sweden)

    Vendula Rusnakova

    Full Text Available Astrocytes perform control and regulatory functions in the central nervous system; heterogeneity among them is still a matter of debate due to limited knowledge of their gene expression profiles and functional diversity. To unravel astrocyte heterogeneity during postnatal development and after focal cerebral ischemia, we employed single-cell gene expression profiling in acutely isolated cortical GFAP/EGFP-positive cells. Using a microfluidic qPCR platform, we profiled 47 genes encoding glial markers and ion channels/transporters/receptors participating in maintaining K(+ and glutamate homeostasis per cell. Self-organizing maps and principal component analyses revealed three subpopulations within 10-50 days of postnatal development (P10-P50. The first subpopulation, mainly immature glia from P10, was characterized by high transcriptional activity of all studied genes, including polydendrocytic markers. The second subpopulation (mostly from P20 was characterized by low gene transcript levels, while the third subpopulation encompassed mature astrocytes (mainly from P30, P50. Within 14 days after ischemia (D3, D7, D14, additional astrocytic subpopulations were identified: resting glia (mostly from P50 and D3, transcriptionally active early reactive glia (mainly from D7 and permanent reactive glia (solely from D14. Following focal cerebral ischemia, reactive astrocytes underwent pronounced changes in the expression of aquaporins, nonspecific cationic and potassium channels, glutamate receptors and reactive astrocyte markers.

  1. Understanding the Molecular Basis of Heterogeneity in Induced Pluripotent Stem Cells.

    Science.gov (United States)

    Manian, Kannan V; Aalam, Syed Mohammed Musheer; Bharathan, Sumitha P; Srivastava, Alok; Velayudhan, Shaji R

    2015-12-01

    Reprogramming of somatic cells to generate induced pluripotent stem cells (iPSCs) has considerable latency and generates epigenetically distinct partially and fully reprogrammed clones. To understand the molecular basis of reprogramming and to distinguish the partially reprogrammed iPSC clones (pre-iPSCs), we analyzed several of these clones for their molecular signatures. Using a combination of markers that are expressed at different stages of reprogramming, we found that the partially reprogrammed stable clones have significant morphological and molecular heterogeneity in their response to transition to the fully pluripotent state. The pre-iPSCs had significant levels of OCT4 expression but exhibited variable levels of mesenchymal-to-epithelial transition. These novel molecular signatures that we identified would help in using these cells to understand the molecular mechanisms in the late of stages of reprogramming. Although morphologically similar mouse iPSC clones showed significant heterogeneity, the human iPSC clones isolated initially on the basis of morphology were highly homogeneous with respect to the levels of pluripotency. PMID:26562626

  2. Cell-Autonomous Heterogeneity of Nutrient Uptake in White Adipose Tissue of Rhesus Macaques

    OpenAIRE

    Varlamov, Oleg; Chu, Michael; Cornea, Anda; Sampath, Harini; Roberts, Charles T.

    2014-01-01

    Phenotypic diversity may play an adaptive role by providing graded biological responses to fluctuations in environmental stimuli. We used single-cell imaging of the metabolizable fluorescent fatty acid analog 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-C12 and fluorescent 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-D-glucose (2-NBDG) to explore cellular heterogeneity in nutrient uptake in white adipose tissue (WAT) explants of rhesus macaques. Surprisingly, WAT displayed a...

  3. High cell density cultivation of the chemolithoautotrophic bacterium Nitrosomonas europaea.

    Science.gov (United States)

    Papp, Benedek; Török, Tibor; Sándor, Erzsébet; Fekete, Erzsébet; Flipphi, Michel; Karaffa, Levente

    2016-05-01

    Nitrosomonas europaea is a chemolithoautotrophic nitrifier, a gram-negative bacterium that can obtain all energy required for growth from the oxidation of ammonia to nitrite, and this may be beneficial for various biotechnological and environmental applications. However, compared to other bacteria, growth of ammonia oxidizing bacteria is very slow. A prerequisite to produce high cell density N. europaea cultures is to minimize the concentrations of inhibitory metabolic by-products. During growth on ammonia nitrite accumulates, as a consequence, N. europaea cannot grow to high cell concentrations under conventional batch conditions. Here, we show that single-vessel dialysis membrane bioreactors can be used to obtain substantially increased N. europaea biomasses and substantially reduced nitrite levels in media initially containing high amounts of the substrate. Dialysis membrane bioreactor fermentations were run in batch as well as in continuous mode. Growth was monitored with cell concentration determinations, by assessing dry cell mass and by monitoring ammonium consumption as well as nitrite formation. In addition, metabolic activity was probed with in vivo acridine orange staining. Under continuous substrate feed, the maximal cell concentration (2.79 × 10(12)/L) and maximal dry cell mass (0.895 g/L) achieved more than doubled the highest values reported for N. europaea cultivations to date. PMID:26358065

  4. Heterogeneous generation of new cells in the adult echinoderm nervous system

    Directory of Open Access Journals (Sweden)

    Vladimir S. Mashanov

    2015-09-01

    Full Text Available Adult neurogenesis, generation of new functional cells in the mature central nervous system (CNS, has been documented in a number of diverse organisms, ranging from humans to invertebrates. However, the origin and evolution of this phenomenon is still poorly understood for many of the key phylogenetic groups. Echinoderms are one such phylum, positioned as a sister group to chordates within the monophyletic clade Deuterostomia. They are well known for the ability of their adult organs, including the CNS, to completely regenerate after injury. Nothing is known, however, about production of new cells in the nervous tissue under normal physiological conditions in these animals. In this study, we show that new cells are continuously generated in the mature radial nerve cord (RNC of the sea cucumber Holothuria glaberrima. Importantly, this neurogenic activity is not evenly distributed, but is significantly more extensive in the lateral regions of the RNC than along the midline. Some of the new cells generated in the apical region of the ectoneural neuroepithelium leave their place of origin and migrate basally to populate the neural parenchyma. Gene expression analysis showed that generation of new cells in the adult sea cucumber CNS is associated with transcriptional activity of genes known to be involved in regulation of various aspects of neurogenesis in other animals. Further analysis of one of those genes, the transcription factor Myc showed that it is expressed, in some, but not all radial glial cells, suggesting heterogeneity of this CNS progenitor cell population in echinoderms.

  5. Defect density and dielectric constant in perovskite solar cells

    International Nuclear Information System (INIS)

    We report on measurement of dielectric constant, mid-gap defect density, Urbach energy of tail states in CH3NH3PbIxCl1−x perovskite solar cells. Midgap defect densities were estimated by measuring capacitance vs. frequency at different temperatures and show two peaks, one at 0.66 eV below the conduction band and one at 0.24 eV below the conduction band. The attempt to escape frequency is in the range of 2 × 1011/s. Quantum efficiency data indicate a bandgap of 1.58 eV. Urbach energies of valence and conduction band are estimated to be ∼16 and ∼18 meV. Measurement of saturation capacitance indicates that the relative dielectric constant is ∼18.

  6. Defect density and dielectric constant in perovskite solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Samiee, Mehran; Konduri, Siva; Abbas, Hisham A.; Joshi, Pranav; Zhang, Liang; Dalal, Vikram, E-mail: vdalal@iastate.edu [Department of Electrical and Computer Engineering, Iowa State University, Ames, Iowa 50011 (United States); Ganapathy, Balaji; Kottokkaran, Ranjith; Noack, Max [Microelectronics Research Center, Iowa State University, Ames, Iowa 50011 (United States); Kitahara, Andrew [Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011 (United States)

    2014-10-13

    We report on measurement of dielectric constant, mid-gap defect density, Urbach energy of tail states in CH{sub 3}NH{sub 3}PbI{sub x}Cl{sub 1−x} perovskite solar cells. Midgap defect densities were estimated by measuring capacitance vs. frequency at different temperatures and show two peaks, one at 0.66 eV below the conduction band and one at 0.24 eV below the conduction band. The attempt to escape frequency is in the range of 2 × 10{sup 11}/s. Quantum efficiency data indicate a bandgap of 1.58 eV. Urbach energies of valence and conduction band are estimated to be ∼16 and ∼18 meV. Measurement of saturation capacitance indicates that the relative dielectric constant is ∼18.

  7. The dendritic density field of a cortical pyramidal cell

    Directory of Open Access Journals (Sweden)

    Hermann eCuntz

    2012-02-01

    Full Text Available Much is known about the computation in individual neurons in the cortical column. Also, the selective connectivity between many cortical neuron types has been studied in great detail. But due to the complexity of this microcircuitry its functional role within the cortical column remains a mystery. Some of the wiring behavior between neurons can be interpreted directly from their particular dendritic and axonal shapes. Here, I describe the dendritic density field as one key element that remains to be better understood. I sketch an approach to relate dendritic density fields in general to their underlying potential connectivity schemes. As an example, I show how the characteristic shape of a cortical pyramidal cell appears as a direct consequence of connecting inputs arranged in two separate parallel layers.

  8. Natural Mineral-Based Solid Oxide Fuel Cell with Heterogeneous Nanocomposite Derived from Hematite and Rare-Earth Minerals.

    Science.gov (United States)

    Xia, Chen; Cai, Yixiao; Ma, Yue; Wang, Baoyuan; Zhang, Wei; Karlsson, Mikael; Wu, Yan; Zhu, Bin

    2016-08-17

    Solid oxide fuel cells (SOFCs) have attracted much attention worldwide because of their potential for providing clean and reliable electric power. However, their commercialization is subject to the high operating temperatures and costs. To make SOFCs more competitive, here we report a novel and attractive nanocomposite hematite-LaCePrOx (hematite-LCP) synthesized from low-cost natural hematite and LaCePr-carbonate mineral as an electrolyte candidate. This heterogeneous composite exhibits a conductivity as high as 0.116 S cm(-1) at 600 °C with an activation energy of 0.50 eV at 400-600 °C. For the first time, a fuel cell using such a natural mineral-based composite demonstrates a maximum power density of 625 mW cm(-2) at 600 °C and notable power output of 386 mW cm(-2) at 450 °C. The extraordinary ionic conductivity and device performances are primarily attributed to the heterophasic interfacial conduction effect of the hematite-LCP composite. These superior properties, along with the merits of ultralow cost, abundant storage, and eco-friendliness, make the new composite a highly promising material for commercial SOFCs. PMID:27483426

  9. X-ray absorption spectroscopy and imaging of heterogeneous hydrothermal mixtures using a diamond microreactor cell

    International Nuclear Information System (INIS)

    Hydrothermal synthesis is an important route to novel materials. Hydrothermal chemistry is also an important aspect of geochemistry and a variety of waste remediation technologies. There is a significant lack of information about the speciation of inorganic compounds under hydrothermal conditions. For these reasons we describe a high-temperature, high-pressure cell that allows one to acquire both x-ray absorption fine structure (XAFS) spectra and x-ray transmission and absorption images of heterogeneous hydrothermal mixtures. We demonstrate the utility of the method by measuring the Cu(I) speciation in a solution containing both solid and dissolved Cu phases at temperatures up to 325oC. X-ray imaging of the various hydrothermal phases allows micro-XAFS to be collected from different phases within the heterogeneous mixture. The complete structural characterization of a soluble bichloro-cuprous species was determined. In situ XAFS measurements were used to define the oxidation state and the first-shell coordination structure. The Cu--Cl distance was determined to be 2.12 Aa for the CuCl2- species and the complete loss of tightly bound waters of hydration in the first shell was observed. The microreactor cell described here can be used to test thermodynamic models of solubility and redox chemistry of a variety of different hydrothermal mixtures

  10. Thromboxane A2 receptors are influenced by cell density in cultured rat aortic smooth muscle cells

    International Nuclear Information System (INIS)

    The influence of cell density on the binding characteristics of thromboxane A2/prostaglandin H2 (TXA2/PGH2) receptors in rat aortic vascular smooth muscle cells in culture were determined using (1S- (1α, 2β (5Z), 3a (1E, 3R*), 4α)) - (3- (3-hydroxy-4- (4'-iodophenoxy)-1-butyenyl)-7-oxabicyclo-(2.2.1)heptan-2yl)-5-heptenoic acid (125I-BOP). The Bmax for 125I-BOP was 5,430 ± 139 sites/cell (26.9 ± 5.7 fmoles/mg protein) for cells cultured in 1% fetal calf serum and 2,809 ± 830 sites/cell (13.1 ± 2.2 fmoles/mg protein) for cells cultured in 10% fetal calf serum. Cells were allowed to grow to varying densities and then harvested for assay. There was a negative correlation between the Bmax and the cell density per flask. The Kd for I-BOP did not significantly vary in any of the studies. The results demonstrate that cell density plays an important role in influencing the expression of vascular TXA2/PGH2 receptors

  11. Dynamic heterogeneity and non-Gaussian statistics for acetylcholine receptors on live cell membrane

    Science.gov (United States)

    He, W.; Song, H.; Su, Y.; Geng, L.; Ackerson, B. J.; Peng, H. B.; Tong, P.

    2016-05-01

    The Brownian motion of molecules at thermal equilibrium usually has a finite correlation time and will eventually be randomized after a long delay time, so that their displacement follows the Gaussian statistics. This is true even when the molecules have experienced a complex environment with a finite correlation time. Here, we report that the lateral motion of the acetylcholine receptors on live muscle cell membranes does not follow the Gaussian statistics for normal Brownian diffusion. From a careful analysis of a large volume of the protein trajectories obtained over a wide range of sampling rates and long durations, we find that the normalized histogram of the protein displacements shows an exponential tail, which is robust and universal for cells under different conditions. The experiment indicates that the observed non-Gaussian statistics and dynamic heterogeneity are inherently linked to the slow-active remodelling of the underlying cortical actin network.

  12. Enhanced Inter-cell Interference Coordination for Heterogeneous Networks in LTE-Advanced: A Survey

    CERN Document Server

    Lindbom, Lars; Krishnamurthy, Sandeep; Yao, Chunhai; Miki, Nobuhiko; Chandrasekhar, Vikram

    2011-01-01

    Heterogeneous networks (het-nets) - comprising of conventional macrocell base stations overlaid with femtocells, picocells and wireless relays - offer cellular operators burgeoning traffic demands through cell-splitting gains obtained by bringing users closer to their access points. However, the often random and unplanned location of these access points can cause severe near-far problems, typically solved by coordinating base-station transmissions to minimize interference. Towards this direction, the 3rd generation partnership project Long Term Evolution-Advanced (3GPP-LTE or Rel-10) standard introduces time-domain inter-cell interference coordination (ICIC) for facilitating a seamless deployment of a het-net overlay. This article surveys the key features encompassing the physical layer, network layer and back-hauling aspects of time-domain ICIC in Rel-10.

  13. Heterogeneous reactors

    International Nuclear Information System (INIS)

    The microscopic study of a cell is meant for the determination of the infinite multiplication factor of the cell, which is given by the four factor formula: K(infinite) = n(epsilon)pf. The analysis of an homogeneous reactor is similar to that of an heterogeneous reactor, but each factor of the four factor formula can not be calculated by the formulas developed in the case of an homogeneous reactor. A great number of methods was developed for the calculation of heterogeneous reactors and some of them are discussed. (Author)

  14. Corneal endothelial cell density and morphology in Phramongkutklao Hospital

    Directory of Open Access Journals (Sweden)

    Narumon Sopapornamorn

    2008-03-01

    Full Text Available Narumon Sopapornamorn1, Manapon Lekskul1, Suthee Panichkul21Department of Ophthalmology, Phramongkutklao Hospital, Bangkok, Thailand; 2Department of Obstetrics and Gynecology, Phramongkutklao College of Medicine, Bangkok, ThailandObjective: To describe the corneal endothelial density and morphology in patients of Phramongkutklao Hospital and the relationship between endothelial cell parameters and other factors.Methods: Four hundred and four eyes of 202 volunteers were included. Noncontact specular microscopy was performed after taking a history and testing the visual acuity, intraocular pressure measurement, Schirmer’s test and routine eye examination by slit lamp microscope. The studied parameters included mean endothelial cell density (MCD, coefficient of variation (CV, and percentage of hexagonality.Results: The mean age of volunteers was 45.73 years; the range being 20 to 80 years old. Their MCD (SD, mean percentage of CV (SD and mean (SD percentage of hexagonality were 2623.49(325 cell/mm2, 39.43(8.23% and 51.50(10.99%, respectively. Statistically, MCD decreased significantly with age (p < 0.01. There was a significant difference in the percentage of CV between genders. There was no statistical significance between parameters and other factors.Conclusion: The normative data of the corneal endothelium of Thai eyes indicated that, statistically, MCD decreased significantly with age. Previous studies have reported no difference in MCD, percentage of CV, and percentage of hexagonality between gender. Nevertheless, significantly different percentages of CV between genders were presented in this study.Keywords: Corneal endothelial cell, parameters, age, gender, smoking, Thailand

  15. Clonal characterization of rat muscle satellite cells: proliferation, metabolism and differentiation define an intrinsic heterogeneity.

    Directory of Open Access Journals (Sweden)

    Carlo A Rossi

    Full Text Available Satellite cells (SCs represent a distinct lineage of myogenic progenitors responsible for the postnatal growth, repair and maintenance of skeletal muscle. Distinguished on the basis of their unique position in mature skeletal muscle, SCs were considered unipotent stem cells with the ability of generating a unique specialized phenotype. Subsequently, it was demonstrated in mice that opposite differentiation towards osteogenic and adipogenic pathways was also possible. Even though the pool of SCs is accepted as the major, and possibly the only, source of myonuclei in postnatal muscle, it is likely that SCs are not all multipotent stem cells and evidences for diversities within the myogenic compartment have been described both in vitro and in vivo. Here, by isolating single fibers from rat flexor digitorum brevis (FDB muscle we were able to identify and clonally characterize two main subpopulations of SCs: the low proliferative clones (LPC present in major proportion (approximately 75% and the high proliferative clones (HPC, present instead in minor amount (approximately 25%. LPC spontaneously generate myotubes whilst HPC differentiate into adipocytes even though they may skip the adipogenic program if co-cultured with LPC. LPC and HPC differ also for mitochondrial membrane potential (DeltaPsi(m, ATP balance and Reactive Oxygen Species (ROS generation underlying diversities in metabolism that precede differentiation. Notably, SCs heterogeneity is retained in vivo. SCs may therefore be comprised of two distinct, though not irreversibly committed, populations of cells distinguishable for prominent differences in basal biological features such as proliferation, metabolism and differentiation. By these means, novel insights on SCs heterogeneity are provided and evidences for biological readouts potentially relevant for diagnostic purposes described.

  16. Probing topological relations between high-density and low-density regions of 2MASS with hexagon cells

    International Nuclear Information System (INIS)

    We introduced a new two-dimensional (2D) hexagon technique for probing the topological structure of the universe in which we mapped regions of the sky with high and low galaxy densities onto a 2D lattice of hexagonal unit cells. We defined filled cells as corresponding to high-density regions and empty cells as corresponding to low-density regions. The numbers of filled cells and empty cells were kept the same by controlling the size of the cells. By analyzing the six sides of each hexagon, we could obtain and compare the statistical topological properties of high-density and low-density regions of the universe in order to have a better understanding of the evolution of the universe. We applied this hexagonal method to Two Micron All Sky Survey data and discovered significant topological differences between the high-density and low-density regions. Both regions had significant (>5σ) topological shifts from both the binomial distribution and the random distribution.

  17. On the suitability of ultrathin detectors for absorbed dose assessment in the presence of high-density heterogeneities

    OpenAIRE

    Bueno Vizcarra, Marta; Carrasco, P. (Paula); Jornet, N.; Muñoz Montplet, C.; Duch Guillen, María Amor

    2014-01-01

    Purpose: The aim of this study was to evaluate the suitability of several detectors for the determination of absorbed dose in bone.; Methods: Three types of ultrathin LiF-based thermoluminescent dosimeters (TLDs) two LiF:Mg,Cu,P-based (MCP-Ns and TLD-2000F) and a Li-7-enriched LiF:Mg,Ti-based (MTS-7s)-as well as EBT2 Gafchromic films were used to measure percentage depth-dose distributions (PDDs) in a water-equivalent phantom with a bone-equivalent heterogeneity for 6 and 18 MV and a set of f...

  18. Assessment of Microbial Fuel Cell Configurations and Power Densities

    KAUST Repository

    Logan, Bruce E.

    2015-07-30

    Different microbial electrochemical technologies are being developed for a many diverse applications, including wastewater treatment, biofuel production, water desalination, remote power sources, and as biosensors. Current and energy densities will always be limited relative to batteries and chemical fuel cells, but these technologies have other advantages based on the self-sustaining nature of the microorganisms that can donate or accept electrons from an electrode, the range of fuels that can be used, and versatility in the chemicals that can be produced. The high cost of membranes will likely limit applications of microbial electrochemical technologies that might require a membrane. For microbial fuel cells, which do not need a membrane, questions remain on whether larger-scale systems can produce power densities similar to those obtained in laboratory-scale systems. It is shown here that configuration and fuel (pure chemicals in laboratory media versus actual wastewaters) remain the key factors in power production, rather than the scale of the application. Systems must be scaled up through careful consideration of electrode spacing and packing per unit volume of reactor.

  19. A role for E-cadherin in ensuring cohesive migration of a heterogeneous population of non-epithelial cells

    OpenAIRE

    Campbell, Kyra; Casanova, Jordi

    2015-01-01

    © 2015 Macmillan Publishers Limited. All rights reserved. Collective cell migration is a key process underlying the morphogenesis of many organs as well as tumour invasion, which very often involves heterogeneous cell populations. Here we investigated how such populations can migrate cohesively in the Drosophila posterior midgut, comprised of epithelial and mesenchymal cells and show a novel role for the epithelial adhesion molecule E-cadherin (E-Cad) in mesenchymal cells. Despite a lack of j...

  20. An exquisite cross-control mechanism among endothelial cell fate regulators directs the plasticity and heterogeneity of lymphatic endothelial cells

    Science.gov (United States)

    Kang, Jinjoo; Yoo, Jaehyuk; Lee, Sunju; Tang, Wanli; Aguilar, Berenice; Ramu, Swapnika; Choi, Inho; Otu, Hasan H.; Shin, Jay W.; Dotto, G. Paolo; Koh, Chester J.; Detmar, Michael

    2010-01-01

    Arteriovenous-lymphatic endothelial cell fates are specified by the master regulators, namely, Notch, COUP-TFII, and Prox1. Whereas Notch is expressed in the arteries and COUP-TFII in the veins, the lymphatics express all 3 cell fate regulators. Previous studies show that lymphatic endothelial cell (LEC) fate is highly plastic and reversible, raising a new concept that all 3 endothelial cell fates may coreside in LECs and a subtle alteration can result in a reprogramming of LEC fate. We provide a molecular basis verifying this concept by identifying a cross-control mechanism among these cell fate regulators. We found that Notch signal down-regulates Prox1 and COUP-TFII through Hey1 and Hey2 and that activated Notch receptor suppresses the lymphatic phenotypes and induces the arterial cell fate. On the contrary, Prox1 and COUP-TFII attenuate vascular endothelial growth factor signaling, known to induce Notch, by repressing vascular endothelial growth factor receptor-2 and neuropilin-1. We show that previously reported podoplanin-based LEC heterogeneity is associated with differential expression of Notch1 in human cutaneous lymphatics. We propose that the expression of the 3 cell fate regulators is controlled by an exquisite feedback mechanism working in LECs and that LEC fate is a consequence of the Prox1-directed lymphatic equilibrium among the cell fate regulators. PMID:20351309

  1. B cells contribute to heterogeneity of IL-17 producing cells in rheumatoid arthritis and healthy controls.

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    Paul Martin Schlegel

    Full Text Available Secretion of the proinflammatory cytokine Interleukin-17A (IL-17A is the hallmark of a unique lineage of CD4 T cells designated Th17 cells, which may play a crucial role in the pathogenesis of rheumatoid arthritis (RA and many autoimmune diseases. Recently, IL-17-producing cells other than T cells have been described, including diverse innate immune cells. Here, we show that the cellular sources of IL-17A in RA include a significant number of non-T cells. Multicolour fluorescence analysis of IL-17-expressing peripheral blood mononuclear cells (PBMC revealed larger proportions of IL-17(+CD3(- non-T cells in RA patients than in healthy controls (constitutive, 13.6% vs. 8.4%, and after stimulation with PMA/ionomycin 17.4% vs. 7.9% p < 0.001 in both cases. The source of IL-17 included CD3(-CD56(+ NK cells, CD3(-CD14(+ myeloid cells as well as the expected CD3(+CD4(+ Th17 cells and surprisingly a substantial number of CD3(-CD19(+ B cells. The presence of IL-17A-expressing B cells was confirmed by specific PCR of peripheral MACS-sorted CD19(+ B cells, as well as by the analysis of different EBV-transformed B cell lines. Here we report for the first time that in addition to Th17 cells and different innate immune cells B cells also contribute to the IL-17A found in RA patients and healthy controls.

  2. Ultra-deep T cell receptor sequencing reveals the complexity and intratumour heterogeneity of T cell clones in renal cell carcinomas.

    Science.gov (United States)

    Gerlinger, Marco; Quezada, Sergio A; Peggs, Karl S; Furness, Andrew J S; Fisher, Rosalie; Marafioti, Teresa; Shende, Vishvesh H; McGranahan, Nicholas; Rowan, Andrew J; Hazell, Steven; Hamm, David; Robins, Harlan S; Pickering, Lisa; Gore, Martin; Nicol, David L; Larkin, James; Swanton, Charles

    2013-12-01

    The recognition of cancer cells by T cells can impact upon prognosis and be exploited for immunotherapeutic approaches. This recognition depends on the specific interaction between antigens displayed on the surface of cancer cells and the T cell receptor (TCR), which is generated by somatic rearrangements of TCR α- and β-chains (TCRb). Our aim was to assess whether ultra-deep sequencing of the rearranged TCRb in DNA extracted from unfractionated clear cell renal cell carcinoma (ccRCC) samples can provide insights into the clonality and heterogeneity of intratumoural T cells in ccRCCs, a tumour type that can display extensive genetic intratumour heterogeneity (ITH). For this purpose, DNA was extracted from two to four tumour regions from each of four primary ccRCCs and was analysed by ultra-deep TCR sequencing. In parallel, tumour infiltration by CD4, CD8 and Foxp3 regulatory T cells was evaluated by immunohistochemistry and correlated with TCR-sequencing data. A polyclonal T cell repertoire with 367-16 289 (median 2394) unique TCRb sequences was identified per tumour region. The frequencies of the 100 most abundant T cell clones/tumour were poorly correlated between most regions (Pearson correlation coefficient, -0.218 to 0.465). 3-93% of these T cell clones were not detectable across all regions. Thus, the clonal composition of T cell populations can be heterogeneous across different regions of the same ccRCC. T cell ITH was higher in tumours pretreated with an mTOR inhibitor, which could suggest that therapy can influence adaptive tumour immunity. These data show that ultra-deep TCR-sequencing technology can be applied directly to DNA extracted from unfractionated tumour samples, allowing novel insights into the clonality of T cell populations in cancers. These were polyclonal and displayed ITH in ccRCC. TCRb sequencing may shed light on mechanisms of cancer immunity and the efficacy of immunotherapy approaches. PMID:24122851

  3. Discovery of Power-Law Growth in the Self-Renewal of Heterogeneous Glioma Stem Cell Populations.

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    Michiya Sugimori

    Full Text Available Accumulating evidence indicates that cancer stem cells (CSCs drive tumorigenesis. This suggests that CSCs should make ideal therapeutic targets. However, because CSC populations in tumors appear heterogeneous, it remains unclear how CSCs might be effectively targeted. To investigate the mechanisms by which CSC populations maintain heterogeneity during self-renewal, we established a glioma sphere (GS forming model, to generate a population in which glioma stem cells (GSCs become enriched. We hypothesized, based on the clonal evolution concept, that with each passage in culture, heterogeneous clonal sublines of GSs are generated that progressively show increased proliferative ability.To test this hypothesis, we determined whether, with each passage, glioma neurosphere culture generated from four different glioma cell lines become progressively proliferative (i.e., enriched in large spheres. Rather than monitoring self-renewal, we measured heterogeneity based on neurosphere clone sizes (#cells/clone. Log-log plots of distributions of clone sizes yielded a good fit (r>0.90 to a straight line (log(% total clones = k*log(#cells/clone indicating that the system follows a power-law (y = xk with a specific degree exponent (k = -1.42. Repeated passaging of the total GS population showed that the same power-law was maintained over six passages (CV = -1.01 to -1.17. Surprisingly, passage of either isolated small or large subclones generated fully heterogeneous populations that retained the original power-law-dependent heterogeneity. The anti-GSC agent Temozolomide, which is well known as a standard therapy for glioblastoma multiforme (GBM, suppressed the self-renewal of clones, but it never disrupted the power-law behavior of a GS population.Although the data above did not support the stated hypothesis, they did strongly suggest a novel mechanism that underlies CSC heterogeneity. They indicate that power-law growth governs the self-renewal of heterogeneous

  4. Bovine mammary dendritic cells: a heterogeneous population, distinct from macrophages and similar in phenotype to afferent lymph veiled cells.

    Science.gov (United States)

    Maxymiv, Nicolas G; Bharathan, Mini; Mullarky, Isis K

    2012-01-01

    Dendritic cells (DC) are a heterogeneous population of professional antigen presenting cells and are potent stimulators of naïve T-cells. However, there is little previous research describing DC in bovine mammary tissue, primarily because of the difficulty distinguishing these cells from macrophages, which possess a similar phenotype. Using immunohistofluorescence and a combination of markers (MHC-II, CD205, CD11c), DC were localized in the bovine mammary gland and supramammary lymph node. In mammary tissue DC were found within the alveolar epithelium and within the intralobular connective tissue. In the lymph node DC were found on the periphery of B-cell areas, in the cortex, and among T-cells in the paracortex and medulla. DC in mammary parenchyma and supramammary lymph nodes were quantified and further characterized using flow cytometry. DC were CD11c(hi), CD14(lo) cells that expressed MHC-II and CD205. DC could be distinguished from macrophages based on their low CD14 expression. This research provides a better understanding of mammary gland immunology, while potentially aiding in the targeting of antigens to mucosal DC for vaccine development. PMID:22019401

  5. Finite element modelling of elastic intraplate stresses due to heterogeneities in crustal density and mechanical properties for the Jabalpur earthquake region, central India

    Indian Academy of Sciences (India)

    A Manglik; S Thiagarajan; A V Mikhailova; Yu Rebetsky

    2008-04-01

    Deep lower crustal intraplate earthquakes are infrequent and the mechanism of their occurrence is not well understood. The Narmada–Son-lineament region in central India has experienced two such events, the 1938 Satpura earthquake and the 1997 Jabalpur earthquake, having a focal depth of more than 35 km. We have estimated elastic stresses due to the crustal density and mechanical properties heterogeneities along the Hirapur–Mandla profile passing through the Jabalpur earthquake region to analyse conditions suitable for the concentration of shear stresses in the hypocentral region of this earthquake. Elastic stresses have been computed by a finite element method for a range of material parameters. The results indicate that the shear stresses generated by the density heterogeneities alone are not able to locally enhance the stress concentration in the hypocentral region. The role of mechanical properties of various crustal layers is important in achieving this localization of stresses. Among a range of material parameters analysed, the model with a mechanically strong lower crust overlying a relatively weak sub-Moho layer is able to enhance the stress concentration in the hypocentral region, implying a weaker mantle in comparison to the lower crust for this region of central India.

  6. Characterization of two novel cell lines with distinct heterogeneity derived from a single human bile duct carcinoma.

    Directory of Open Access Journals (Sweden)

    Jinghan Wang

    Full Text Available BACKGROUND: Intratumoral heterogeneity reflects subclonal diversity and accounts for a variety of clinically defined phenotypes including the development of drug resistance and recurrence. However, intratumoral heterogeneity of bile duct carcinoma (BDC is rarely studied. METHODS: Two highly heterogeneous cell lines named EH-CA1a and EH-CA1b were established from a primary tumor tissue of a pathologically proven BDC. Distinct heterogeneity and underlying mechanisms of two cell lines in karyotype, colony formation, tumorgenicity, and sensitivity to chemoradiotherapy were intensively studied. RESULTS: Both cell lines showed typical morphology of cancer cells. EH-CA1a cells grew as free-floating aggregates, while EH-CA1b cells grew adherently as a monolayer. EH-CA1a cells had higher cloning efficiencies and were able to keep proliferating under hypoxic condition. Coincidentally, hypoxia-induced factor-1α (HIF1α and vascular endothelial growth factor (VEGF mRNA were significantly higher in EH-CA1a cells than in EH-CA1b cells. Both cell lines were tumorigenic in nude mouse, however, EH-CA1a cells showed more aggressive characteristics. Most importantly, the EH-CA1a cells showed much more resistance against radiation and chemotherapy with gemcitabine. Metastasis-related genes including matrix metalloproteinase 2 (MMP-2, MMP-9, epithelial-mesenchymal transition (EMT markers such as Vimentin, Snail, and Twist, are more highly expressed in EH-CA1a cells than in EH-CA1b cells. Moreover, the percentage of cells expressing cancer stem cell-like marker, CD133, in EH-CA1a cells is much higher than that in EH-CA1b cells. Moreover, knockdown of CD133 in both EH-CA1a and EH-CA1b cells significantly reduced their invasive potential and increased their sensitivities to radiation and gemcitabine, suggesting the differential expression of CD133 protein may partially account for the difference in malignancy between these two cancer cells. CONCLUSION: Establishment

  7. Heterogeneity in predisposition of hepatic cells to be induced into pancreatic endocrine cells by PDX-1

    Institute of Scientific and Technical Information of China (English)

    Shun Lu; Wei-Ping Wang; Xiao-Fei Wang; Zong-Mei Zheng; Ping Chen; Kang-Tao Ma; Chun-Yan Zhou

    2005-01-01

    AIM: The role of Pancreatic and Duodenal Homeobox-1(PDX-1) as a major regulator of pancreatic development determines the function and phenotype of β cell. In this study, potential plasticity of liver cells into pancreatic endocrine cells induced by PDX-1 was evaluated.METHODS: Human hepatoma cell line HepG2 was stably transfected with mammalian expression plasmid pcDNA3-PDX encoding human PDX-1 gene. Ectopic expression of PDX-1 and insulin were detected by RT-PCR,Western blot and/or immunostaining. PDX-1+ HepG2 cells were transplanted under renal capsule of STZ-induced diabetic nude mice (n = 16) to examine the inducing effect in vivo.RESULTS: Exogenous PDX-1 transgene was proved to express effectively in HepG2 cell at both mRNA and protein levels. The expression of endogenous insulin and some βcell-specific differentiation markers and transcription factors were not induced in PDX-1+ HepG2 cells. When transplanted under renal capsule of STZ-induced diabetic nude mice, PDX-1+ HepG2 cells did not generate insulinproducing cells. These data indicated that stable transfected PDX-1 could not convert hepatoma cell line HepG2 to pancreatic cells in vitro or in vivo. Mature hepatocytes might need much more complicated or rigorous conditions to be shifted to insulin-producing cells.CONCLUSION: The expression of exogenous PDX-1 is not sufficient to induce relatively mature hepatocytes differentiating into insulin-producing cells.

  8. Embryonic Stem Cell-Derived Cardiomyocyte Heterogeneity and the Isolation of Immature and Committed Cells for Cardiac Remodeling and Regeneration

    Directory of Open Access Journals (Sweden)

    Kenneth R. Boheler

    2011-01-01

    Full Text Available Pluripotent stem cells represent one promising source for cell replacement therapy in heart, but differentiating embryonic stem cell-derived cardiomyocytes (ESC-CMs are highly heterogeneous and show a variety of maturation states. In this study, we employed an ESC clonal line that contains a cardiac-restricted ncx1 promoter-driven puromycin resistance cassette together with a mass culture system to isolate ESC-CMs that display traits characteristic of very immature CMs. The cells display properties of proliferation, CM-restricted markers, reduced mitochondrial mass, and hypoxia-resistance. Following transplantation into rodent hearts, bioluminescence imaging revealed that immature cells, but not more mature CMs, survived for at least one month following injection. These data and comparisons with more mature cells lead us to conclude that immature hypoxia resistant ESC-CMs can be isolated in mass in vitro and, following injection into heart, form grafts that may mediate long-term recovery of global and regional myocardial contractile function following infarction.

  9. Cell-centered scheme for heterogeneous anisotropic diffusion problems on general meshes

    International Nuclear Information System (INIS)

    We present a new scheme for the discretization of heterogeneous anisotropic diffusion problems on general meshes. With light assumptions, we show that the algorithm can be written as a cell-centered scheme with a small stencil and that it is convergent for discontinuous tensors. The key point of the proof consists in showing both the strong and the weak consistency of the method. Besides, we study non-linear corrections to correct the FECC scheme, in order to satisfy the discrete maximum principle (DMP). The efficiency of the scheme is demonstrated through numerical tests of the 5. and 6. International Symposium on Finite Volumes for Complex Applications - FVCA 5 and 6. Moreover, the comparison with classical finite volume schemes emphasizes the precision of the method. We also show the good behaviour of the algorithm for nonconforming meshes. In addition, we give some numerical tests to check the existence for the non-linear FECC schemes. (author)

  10. 3D modeling of density and substratum topography effects in a heterogeneous aquifer: the case of the hundred year saline pollution in the Upper Rhine valley

    Science.gov (United States)

    Lucas, Yann; Younes, Anis; Ackerer, Philippe

    2014-05-01

    Knowing the distribution of fresh and saline groundwater is an important issue of the sustainable management of water resources. Here we deal with groundwater plume pollution coming from brines of salted waste heaps in the Upper Rhine aquifer, one of the most important groundwater resources for Western Europe. It has been contaminated in its upstream part by mining brine infiltration coming from potash extraction which started at the beginning of the twentieth century. The salty residues were stored in waste heaps near the mine shafts, and, due to rainwater percolation through the heaps, saline aqueous solutions mixed with groundwater and then progressed in the flow direction, forming high salinity plumes. In the present case, it is proved that density effects are all the more necessary to be considered in a modeling approach that brines density can reach high values just below waste heaps. For this purpose a 3D model is developed using the SEAWAT option of Modflow in a 30 layers model. Simulations are performed on about one hundred years, where chlorine concentration data on the last thirty years are used to constrain the model. In our case, conjugated to a heckled substratum topography, heterogeneous hydrodynamical conditions and the fact that pollution history alternates high pollution phases with relatively low pollution phases, density driven flows lead salted water into original directions downstream waste heaps. From a numerical point of view, it is also shown that discretization degree plays a major role in the density effect modeling.

  11. Degradation of high density lipoprotein in cultured rat luteal cells

    International Nuclear Information System (INIS)

    In rat ovary luteal cells, degradation of high density lipoprotein (HDL) to tricholoracetic acid (TCA)-soluble products accounts for only a fraction of the HDL-derived cholesterol used for steroidogenesis. In this study the authors have investigated the fate of 125I]HDL bound to cultured luteal cells using pulse-chase technique. Luteal cell cultures were pulse labeled with [125I]HDL3 and reincubated in the absence of HDL. By 24 h about 50% of the initallay bound radioactivity was released into the medium, of which 60-65% could be precipitated with 10% TCA. Gel filtration of the chase incubation medium on 10% agarose showed that the amount of TCA-soluble radioactivity was nearly completely accounted for by a sharp peak in the low molecular weight region which was identified as 96% monoiodotyrosine by paper chromatography. The TCA-precipitable radioactivity was nearly completely accounted for by a sharp peak in the low molecular weight region which was identified as 96% monoiodotyrosine by paper chromatography. The TCA-precipitable radioactivity eluted over a wide range of molecular weights (15,000-80,000), and there was very little intact HDL present. Electrophoresis of the chase medium showed that component of the TCA-precipitable portion had mobility similar to apo AI. Lysosomal inhibitors of receptor-mediated endocytosis had no effect on the composition or quantity of radioactivity released during chase incubation. The results show that HDL3 binding to luteal cells is followed by complete degradation of the lipoprotein, although the TCA-soluble part does not reflect the extent of degradation

  12. Heterogenic final cell cycle by chicken retinal Lim1 horizontal progenitor cells leads to heteroploid cells with a remaining replicated genome.

    Directory of Open Access Journals (Sweden)

    Shahrzad Shirazi Fard

    Full Text Available Retinal progenitor cells undergo apical mitoses during the process of interkinetic nuclear migration and newly generated post-mitotic neurons migrate to their prospective retinal layer. Whereas this is valid for most types of retinal neurons, chicken horizontal cells are generated by delayed non-apical mitoses from dedicated progenitors. The regulation of such final cell cycle is not well understood and we have studied how Lim1 expressing horizontal progenitor cells (HPCs exit the cell cycle. We have used markers for S- and G2/M-phase in combination with markers for cell cycle regulators Rb1, cyclin B1, cdc25C and p27Kip1 to characterise the final cell cycle of HPCs. The results show that Lim1+ HPCs are heterogenic with regards to when and during what phase they leave the final cell cycle. Not all horizontal cells were generated by a non-apical (basal mitosis; instead, the HPCs exhibited three different behaviours during the final cell cycle. Thirty-five percent of the Lim1+ horizontal cells was estimated to be generated by non-apical mitoses. The other horizontal cells were either generated by an interkinetic nuclear migration with an apical mitosis or by a cell cycle with an S-phase that was not followed by any mitosis. Such cells remain with replicated DNA and may be regarded as somatic heteroploids. The observed heterogeneity of the final cell cycle was also seen in the expression of Rb1, cyclin B1, cdc25C and p27Kip1. Phosphorylated Rb1-Ser608 was restricted to the Lim1+ cells that entered S-phase while cyclin B1 and cdc25C were exclusively expressed in HPCs having a basal mitosis. Only HPCs that leave the cell cycle after an apical mitosis expressed p27Kip1. We speculate that the cell cycle heterogeneity with formation of heteroploid cells may present a cellular context that contributes to the suggested propensity of these cells to generate cancer when the retinoblastoma gene is mutated.

  13. Anti-cancer efficacy of nonthermal plasma dissolved in a liquid, liquid plasma in heterogeneous cancer cells

    Science.gov (United States)

    Nguyen, Ngoc Hoan; Park, Hyung Jun; Yang, Sang Sik; Choi, Kyeong Sook; Lee, Jong-Soo

    2016-01-01

    The therapeutic potential of nonthermal plasma for cancer treatment has been reported recently. The heterogeneity of cancer cells need to be addressed to design effective anticancer treatments. Here, we show that treatment with nonthermal atmospheric-pressure plasma dissolved in a liquid (liquid plasma) induces oxidative stress in heterogeneous populations of cancer cells and ultimately kills these cells via apoptosis, regardless of genetic status, e.g., mutations in p53 and other DNA-damage-response genes. We found that liquid plasma markedly increased the concentration of intracellular and mitochondrial reactive oxygen species (ROS), reflecting an influx from the extracellular milieu. Liquid plasma contributed to mitochondrial accumulation of ROS and depolarization of mitochondrial membrane potential with consequent cell death. Healthy normal cells, however, were hardly affected by the liquid-plasma treatment. The antioxidant N-acetylcysteine blocked liquid-plasma-induced cell death. A knockdown of CuZn-superoxide dismutase or Mn-SOD enhanced the plasma-induced cell death, whereas expression of exogenous CuZn-SOD, Mn-SOD, or catalase blocked the cell death. These results suggest that the mitochondrial dysfunction mediated by ROS production is a key contributor to liquid-plasma-induced apoptotic cell death, regardless of genetic variation. Thus, liquid plasma may have clinical applications, e.g., the development of therapeutic strategies and prevention of disease progression despite tumor heterogeneity. PMID:27364630

  14. Lens Epithelial Cell Proliferation and Cell Density in Human Age-related Cataract

    Institute of Scientific and Technical Information of China (English)

    Xialin Liu; Yizhi Liu; Jianliang Zheng; Qiang Huang; Huling Zheng

    2000-01-01

    Purpose: To discuss the potential effect of the lens epithelial cell proliferation in age-related cataract.Methods: In vitro cell proliferation was assayed by MTT method to evaluate the lens epithelial cell density, index, and proliferation capacity in normal lens and all kinds of age-related cataract. Capsulotomy specimens from all kinds of patients who underwent cataract phacoemulsification extraction surgery were compared with the lens epithelial specimens from non-cataract lenses of Eye Bank eyes.Results: Lens epithelial cell density of central anterior capsule (LECD) in female normal lens was higher than that in male, LECD in nuclear cataract( > NⅢ ) was higher than that in normal lens, but in the mature cortical cataract, LF CD was lower. Mitotic index of three kinds of age-related cataracts in vivo had no statistical difference, neither did cell proliferation capacity of cultivated cells in vitro.Conclusion: The individual difference of lens epithelial cell density and proliferation capacity in vivo may be an important underlying cause for senile cataract in the cellular level, especially for nuclear cataract.

  15. Solvatochromic Nile Red probes with FRET quencher reveal lipid order heterogeneity in living and apoptotic cells.

    Science.gov (United States)

    Kreder, Rémy; Pyrshev, Kyrylo A; Darwich, Zeinab; Kucherak, Oleksandr A; Mély, Yves; Klymchenko, Andrey S

    2015-06-19

    Detecting and imaging lipid microdomains (rafts) in cell membranes remain a challenge despite intensive research in the field. Two types of fluorescent probes are used for this purpose: one specifically labels a given phase (liquid ordered, Lo, or liquid disordered, Ld), while the other, being environment-sensitive (solvatochromic), stains the two phases in different emission colors. Here, we combined the two approaches by designing a phase-sensitive probe of the Ld phase and a quencher of the Ld phase. The former is an analogue of the recently developed Nile Red-based probe NR12S, bearing a bulky hydrophobic chain (bNR10S), while the latter is based on Black Hole Quencher-2 designed as bNR10S (bQ10S). Fluorescence spectroscopy of large unilamellar vesicles and microscopy of giant vesicles showed that the bNR10S probe can partition specifically into the Ld phase, while bQ10S can specifically quench the NR12S probe in the Ld phase so that only its fraction in the Lo phase remains fluorescent. Thus, the toolkit of two probes with quencher can specifically target Ld and Lo phases and identify their lipid order from the emission color. Application of this toolkit in living cells (HeLa, CHO, and 293T cell lines) revealed heterogeneity in the cell plasma membranes, observed as distinct probe environments close to the Lo and Ld phases of model membranes. In HeLa cells undergoing apoptosis, our toolkit showed the formation of separate domains of the Ld-like phase in the form of blebs. The developed tools open new possibilities in lipid raft research. PMID:25710589

  16. Heterogeneity in radiation-induced DNA damage and repair in tumor and normal cells measured using the comet assay

    International Nuclear Information System (INIS)

    A method for measuring DNA damage to individual cells, based on the technique of microelectrophoresis, was described by Ostling and Johanson in 1984. Cells embedded in agarose are lysed, subjected briefly to an electric field, stained with a fluorescent DNA-binding stain, and viewed using a fluorescence microscope. Broken DNA migrates farther in the electric field, and the cell then resembles a comet with a brightly fluorescent head and a tail region which increases as damage increases. We have used video image analysis to define appropriate features of the comet as a measure of DNA damage, and have quantified damage and repair by ionizing radiation. The assay was optimized for lysing solution, lysing time, electrophoresis time, and propidium iodide concentration using Chinese hamster V79 cells. To assess heterogeneity of response of normal versus malignant cells, damage to both tumor cells and normal cells within mouse SCC-VII tumors was assessed. Tumor cells were separated from macrophages using a cell-sorting method based on differential binding of FITC-conjugated goat anti-mouse IgG. The tail moment, the product of the amount of DNA in the tail and the mean distance of migration in the tail, was the most informative feature of the comet image. Tumor and normal cells showed significant heterogeneity in damage produced by ionizing radiation, although the average amount of damage increased linearly with dose (0-15 Gy) and suggested similar net radiosensitivities for the two cell types. Similarly, DNA repair rate was not significantly different for tumor and normal cells, and most of the cells had repaired the damage by 30 min following exposure to 15 Gy. The heterogeneity in response did not appear to be a result of differences in response through the cell cycle

  17. Phenotypic heterogeneity influences the behavior of rat aortic smooth muscle cells in collagen lattice

    International Nuclear Information System (INIS)

    Phenotypic modulation of vascular smooth muscle cells (SMCs) in atherosclerosis and restenosis involves responses to the surrounding microenvironment. SMCs obtained by enzymatic digestion from tunica media of newborn, young adult (YA) and old rats and from the thickened intima (TI) and underlying media of young adult rat aortas 15 days after ballooning were entrapped in floating populated collagen lattice (PCL). TI-SMCs elongated but were poor at PCL contraction and remodeling and expressed less α2 integrin compared to other SMCs that appeared more dendritic. During early phases of PCL contraction, SMCs showed a marked decrease in the expression of α-smooth muscle actin and myosin. SMCs other than TI-SMCs required 7 days to re-express α-smooth muscle actin and myosin. Only TI-SMCs in PCL were able to divide in 48 h, with a greater proportion in S and G2-M cell cycle phases compared to other SMCs. Anti-α2 integrin antibody markedly inhibited contraction but not proliferation in YA-SMC-PLCs; anti-α1 and anti-α2 integrin antibodies induced a similar slight inhibition in TI-SMC-PCLs. Finally, TI-SMCs rapidly migrated from PCL on plastic reacquiring their epithelioid phenotype. Heterogeneity in proliferation and cytoskeleton as well the capacity to remodel the extracellular matrix are maintained, when SMCs are suspended in PCLs

  18. The effect of 193 nm excimer laser radiation on the human corneal endothelial cell density

    International Nuclear Information System (INIS)

    The effect of 193 nm excimer laser radiation on human corneal endothelial cell density was examined. Fifty-five eyes from 35 patients underwent photorefractive keratectomy for myopia. Photomicrographs of the endothelium were taken a short time before the operation and on an average of 7 months postoperatively with a specular microscope. The average endothelial cell densities were preoperatively 3375 ± 266 cells/mm2 (means ± SD) and postoperatively 3348 ± 287 cells/mm2, corresponding to a fall of 27 cells/mm2 (N = 55). This fall in endothelial cell density was not statistically significant. A significant correlation between the change in cell density and age of the patient was found, with older patients losing more cells (N = 35, 2p < 0.05). The magnification of the specular microscope was found to change with corneal thickness. The importance of correcting the endothelial cell densities for corneal thickness is discussed. (au) 14 refs

  19. The effect of 193 nm excimer laser radiation on the human corneal endothelial cell density

    Energy Technology Data Exchange (ETDEWEB)

    Isager, P.; Hjortdal, J.Oe.; Ehlers, N. [Aarhus Univ. Hospital, Dept. of Ophthalmology, Aarhus (Denmark)

    1996-06-01

    The effect of 193 nm excimer laser radiation on human corneal endothelial cell density was examined. Fifty-five eyes from 35 patients underwent photorefractive keratectomy for myopia. Photomicrographs of the endothelium were taken a short time before the operation and on an average of 7 months postoperatively with a specular microscope. The average endothelial cell densities were preoperatively 3375 {+-} 266 cells/mm{sup 2} (means {+-} SD) and postoperatively 3348 {+-} 287 cells/mm{sup 2}, corresponding to a fall of 27 cells/mm{sup 2} (N = 55). This fall in endothelial cell density was not statistically significant. A significant correlation between the change in cell density and age of the patient was found, with older patients losing more cells (N = 35, 2p < 0.05). The magnification of the specular microscope was found to change with corneal thickness. The importance of correcting the endothelial cell densities for corneal thickness is discussed. (au) 14 refs.

  20. On the suitability of ultrathin detectors for absorbed dose assessment in the presence of high-density heterogeneities

    Energy Technology Data Exchange (ETDEWEB)

    Bueno, M., E-mail: marta.bueno@upc.edu; Duch, M. A. [Institut de Tècniques Energètiques, Universitat Politècnica de Catalunya, 08028 Barcelona (Spain); Carrasco, P.; Jornet, N. [Servei de Radiofísica i Radioprotecció, Hospital de la Santa Creu i de Sant Pau, 08025 Barcelona (Spain); Muñoz-Montplet, C. [Servei de Física Mèdica i Protecció Radiològica, Institut Català d’Oncologia—Girona, 17007 Girona (Spain)

    2014-08-15

    Purpose: The aim of this study was to evaluate the suitability of several detectors for the determination of absorbed dose in bone. Methods: Three types of ultrathin LiF-based thermoluminescent dosimeters (TLDs)—two LiF:Mg,Cu,P-based (MCP-Ns and TLD-2000F) and a{sup 7}Li-enriched LiF:Mg,Ti-based (MTS-7s)—as well as EBT2 Gafchromic films were used to measure percentage depth-dose distributions (PDDs) in a water-equivalent phantom with a bone-equivalent heterogeneity for 6 and 18 MV and a set of field sizes ranging from 5×5 cm{sup 2} to 20×20 cm{sup 2}. MCP-Ns, TLD-2000F, MTS-7s, and EBT2 have active layers of 50, 20, 50, and 30 μm, respectively. Monte Carlo (MC) dose calculations (PENELOPE code) were used as the reference and helped to understand the experimental results and to evaluate the potential perturbation of the fluence in bone caused by the presence of the detectors. The energy dependence and linearity of the TLDs’ response was evaluated. Results: TLDs exhibited flat energy responses (within 2.5%) and linearity with dose (within 1.1%) within the range of interest for the selected beams. The results revealed that all considered detectors perturb the electron fluence with respect to the energy inside the bone-equivalent material. MCP-Ns and MTS-7s underestimated the absorbed dose in bone by 4%–5%. EBT2 exhibited comparable accuracy to MTS-7s and MCP-Ns. TLD-2000F was able to determine the dose within 2% accuracy. No dependence on the beam energy or field size was observed. The MC calculations showed that a50 μm thick detector can provide reliable dose estimations in bone regardless of whether it is made of LiF, water or EBT’s active layer material. Conclusions: TLD-2000F was found to be suitable for providing reliable absorbed dose measurements in the presence of bone for high-energy x-ray beams.

  1. Flow Cytometric Quantification of Peripheral Blood Cell β-Adrenergic Receptor Density and Urinary Endothelial Cell-Derived Microparticles in Pulmonary Arterial Hypertension.

    Directory of Open Access Journals (Sweden)

    Jonathan A Rose

    Full Text Available Pulmonary arterial hypertension (PAH is a heterogeneous disease characterized by severe angiogenic remodeling of the pulmonary artery wall and right ventricular hypertrophy. Thus, there is an increasing need for novel biomarkers to dissect disease heterogeneity, and predict treatment response. Although β-adrenergic receptor (βAR dysfunction is well documented in left heart disease while endothelial cell-derived microparticles (Ec-MPs are established biomarkers of angiogenic remodeling, methods for easy large clinical cohort analysis of these biomarkers are currently absent. Here we describe flow cytometric methods for quantification of βAR density on circulating white blood cells (WBC and Ec-MPs in urine samples that can be used as potential biomarkers of right heart failure in PAH. Biotinylated β-blocker alprenolol was synthesized and validated as a βAR specific probe that was combined with immunophenotyping to quantify βAR density in circulating WBC subsets. Ec-MPs obtained from urine samples were stained for annexin-V and CD144, and analyzed by a micro flow cytometer. Flow cytometric detection of alprenolol showed that βAR density was decreased in most WBC subsets in PAH samples compared to healthy controls. Ec-MPs in urine was increased in PAH compared to controls. Furthermore, there was a direct correlation between Ec-MPs and Tricuspid annular plane systolic excursion (TAPSE in PAH patients. Therefore, flow cytometric quantification of peripheral blood cell βAR density and urinary Ec-MPs may be useful as potential biomarkers of right ventricular function in PAH.

  2. Flow Cytometric Quantification of Peripheral Blood Cell β-Adrenergic Receptor Density and Urinary Endothelial Cell-Derived Microparticles in Pulmonary Arterial Hypertension

    Science.gov (United States)

    Rose, Jonathan A.; Wanner, Nicholas; Cheong, Hoi I.; Queisser, Kimberly; Barrett, Patrick; Park, Margaret; Hite, Corrine; Naga Prasad, Sathyamangla V.; Erzurum, Serpil; Asosingh, Kewal

    2016-01-01

    Pulmonary arterial hypertension (PAH) is a heterogeneous disease characterized by severe angiogenic remodeling of the pulmonary artery wall and right ventricular hypertrophy. Thus, there is an increasing need for novel biomarkers to dissect disease heterogeneity, and predict treatment response. Although β-adrenergic receptor (βAR) dysfunction is well documented in left heart disease while endothelial cell-derived microparticles (Ec-MPs) are established biomarkers of angiogenic remodeling, methods for easy large clinical cohort analysis of these biomarkers are currently absent. Here we describe flow cytometric methods for quantification of βAR density on circulating white blood cells (WBC) and Ec-MPs in urine samples that can be used as potential biomarkers of right heart failure in PAH. Biotinylated β-blocker alprenolol was synthesized and validated as a βAR specific probe that was combined with immunophenotyping to quantify βAR density in circulating WBC subsets. Ec-MPs obtained from urine samples were stained for annexin-V and CD144, and analyzed by a micro flow cytometer. Flow cytometric detection of alprenolol showed that βAR density was decreased in most WBC subsets in PAH samples compared to healthy controls. Ec-MPs in urine was increased in PAH compared to controls. Furthermore, there was a direct correlation between Ec-MPs and Tricuspid annular plane systolic excursion (TAPSE) in PAH patients. Therefore, flow cytometric quantification of peripheral blood cell βAR density and urinary Ec-MPs may be useful as potential biomarkers of right ventricular function in PAH. PMID:27270458

  3. Construction of Larger Area Density-Uniform Plasma with Collisional Inductively Coupled Plasma Cells

    Institute of Scientific and Technical Information of China (English)

    OUYANG Liang; LIU Wandong; BAI Xiaoyan; CHEN Zhipeng; WANG Huihui; LI LUO Chen; JI Liangliang; HU Bei

    2007-01-01

    The plasma density and electron temperature of a multi-source plasma system composed of several collisional inductively coupled plasma (ICP) cells were measured by a double-probe. The discharges of the ICP cells were shown to be independent of each other. Furthermore, the total plasma density at simultaneous multi-cell discharge was observed to be approximately equal to the summation of the plasma density when the cells discharge separately. Based on the linear summation phenomenon, it was shown that a larger area plasma with a uniform density and temperature profile could be constructed with multi-collisional ICP cells.

  4. Heterogeneous density-structure of the northern Chile marine fore-arc and its relation to the rupture of the 2014 Mw8.2 Iquique earthquake

    Science.gov (United States)

    Maksymowicz, Andrei; Ruiz, Javier; Contreras-Reyes, Eduardo

    2016-04-01

    The rupture process of the megathrust earthquakes shows strong complexities that can be explained by a combination of factors such as the inhomogeneous distribution of the accumulated stresses and the inhomogeneous rheological conditions at the seismogenic contact. Numerous authors have highlighted a spatial correlation between nucleation zones, barriers and high slip patches of the megathrust earthquakes with physical heterogeneities both in the oceanic plate and in the continental wedge. The genesis of these heterogeneities has a broad nature and their mechanical impact on the interseismic deformation, coseismic rupture, and aftershocks distribution, is not fully understood. Here we present a quantitative interpretation of the gravity signal in the zone of the Chilean margin where the Mw8.2 Iquique earthquake was ruptured on April 1, 2014. The density structure of the forearc was generated by using a 2-D forward modelling schema specially developed for subduction margins, with a database composed by marine gravity, onshore gravity stations and satellite data. The modelling was constrained by seismological and seismic reflection information. Our analysis shows that the rupture of 2014 Mw8.2 Iquique earthquake and the associated foreshocks present a remarkable spatial correlation with the offshore gravity anomalies. The approximated southern limit of the Iquique 2014 earthquake (~20°30'S) corresponds to a big change in the offshore gravity, from an almost uniform high signal southward to the more low and complex signal to the north. This big gravity change seems to correlate with the southern limit of the segment where the Perdida Ridge collides with the continent. The density models reveal that this limit corresponds to an important northward decrease of the vertical normal stresses over the seismogenic contact and a general northward decrease of continental wedge densities. To the north, the slip patch of the Iquique earthquake is located below a zone of low

  5. Density heterogeneity of lithospheric mantle of Siberia in light of flat surface relief and high amplitudes of Moho and LAB topographies

    Science.gov (United States)

    Cherepanova, Y.; Artemieva, I. M.

    2012-12-01

    Most of the Siberian craton and the West Siberian basin lack surface relief while the amplitudes of topography variations at the Moho and at top of the basement are ca. 20 km and 15 km, correspondingly. Seismic (surface wave tomography and interpretations of ultra-deep Soviet PNE reflection/refraction profiles) and thermal models indicate significant (at least 100 km but possibly as much as 200 km) variations in the lithosphere thickness across the entire region, whereas xenoliths studies from kimberlite-sampled areas confirm the presence of ca. 50 km deep regional LAB undulations. Few published analyses of the regional lithosphere flexure indicate a small thickness of the elastic lithosphere (less than 30 km), atypical of other cratons, and thus do not favor strong flexural support of lithosphere density heterogeneities. Assuming local isostatic equilibrium, we examine the relative contributions of the crust and the lithospheric mantle to maintain surface topography. Parameters controlling lithosphere buoyancy include thicknesses and densities of the crust and the lithospheric mantle, and lithosphere temperatures. We take advantage of our new crustal model, based on a quality-controlled compilation of all seismic models published in international and Russian literature, theses and reports since 1970s. For the lithosphere thickness and temperatures (which are interrelated parameters) we examine two end-member models as constrained by different seismic and thermal models. Assuming no effect of the dynamic topography (which is a valid approximation for most of the region, probably except for its southern margins), we examine compositional density variations in the lithospheric mantle. We also examine the effect of dynamic topography for kimberlite regions, where we adopt xenolith-based data on densities of the lithospheric mantle. The results are compared to seismic data on Pn velocities which show strong anomalies throughout the region (from 7.8 to 8.8 km/s) and to

  6. Fucolipid metabolism as a function of cell population density in normal and murine sarcoma virus-transformed rat cells

    International Nuclear Information System (INIS)

    The incorporation of isotopically labeled fucose into the lipids of normal and murine sarcoma virus-transformed rat cells as a function of cell population density was examined. When normal cells were seeded at low cell density, the levels of the major fucolipids, i.e., fucolipids III and IV, were substantially reduced, but then they increased as the cells approached confluency. This variation in synthesis of fucolipids III and IV appeared to be primarily related to cell density and not to cell growth. Chase experiments revealed that the reduced level of fucolipids III and IV in sparse normal cells is due to decreased synthesis rather than to increased catabolism. In contrast to the observations with normal rat cells, the high level of fucolipid III and the low level of fucolipid IV in murine sarcoma virus-transformed rat cells was shown to be independent of cell population density

  7. Increased power density from a spiral wound microbial fuel cell.

    Science.gov (United States)

    Jia, Boyang; Hu, Dawei; Xie, Beizhen; Dong, Kun; Liu, Hong

    2013-03-15

    Using Microbial fuel cell (MFC) to convert organic and inorganic matter into electricity is of great interest for powering portable devices, which is now still limited by the output of MFC. In this study, a spiral wound MFC (SWMFC) with relatively large volume normalized surface area of separator (4.2 cm(2)/ml) was fabricated to enhance power generation. Compared with double-membrane MFC (DMMFC) and conventional double chamber MFC (DCMFC), the power density of SWMFC increased by 42% and 99% resulted from its lower internal resistance. Besides larger separator area, the better performance of SWMFC benefited from its structure sandwiching the cathodes between two separators. This point was proved again by a comparison of another DCMFC and a triple chamber MFC (TCMFC) as well as a simulation using finite element method. Moreover, the feature of SWMFC was more convenient and compact to scale up. Therefore, SWMFC provides a promising configuration for high power output as a portable power source. PMID:23116542

  8. Estimation of immune cell densities in immune cell conglomerates: an approach for high-throughput quantification.

    Directory of Open Access Journals (Sweden)

    Niels Halama

    Full Text Available BACKGROUND: Determining the correct number of positive immune cells in immunohistological sections of colorectal cancer and other tumor entities is emerging as an important clinical predictor and therapy selector for an individual patient. This task is usually obstructed by cell conglomerates of various sizes. We here show that at least in colorectal cancer the inclusion of immune cell conglomerates is indispensable for estimating reliable patient cell counts. Integrating virtual microscopy and image processing principally allows the high-throughput evaluation of complete tissue slides. METHODOLOGY/PRINCIPAL FINDINGS: For such large-scale systems we demonstrate a robust quantitative image processing algorithm for the reproducible quantification of cell conglomerates on CD3 positive T cells in colorectal cancer. While isolated cells (28 to 80 microm(2 are counted directly, the number of cells contained in a conglomerate is estimated by dividing the area of the conglomerate in thin tissues sections (< or =6 microm by the median area covered by an isolated T cell which we determined as 58 microm(2. We applied our algorithm to large numbers of CD3 positive T cell conglomerates and compared the results to cell counts obtained manually by two independent observers. While especially for high cell counts, the manual counting showed a deviation of up to 400 cells/mm(2 (41% variation, algorithm-determined T cell numbers generally lay in between the manually observed cell numbers but with perfect reproducibility. CONCLUSION: In summary, we recommend our approach as an objective and robust strategy for quantifying immune cell densities in immunohistological sections which can be directly implemented into automated full slide image processing systems.

  9. Human endothelial progenitor cells internalize high-density lipoprotein.

    Directory of Open Access Journals (Sweden)

    Kaemisa Srisen

    Full Text Available Endothelial progenitor cells (EPCs originate either directly from hematopoietic stem cells or from a subpopulation of monocytes. Controversial views about intracellular lipid traffic prompted us to analyze the uptake of human high density lipoprotein (HDL, and HDL-cholesterol in human monocytic EPCs. Fluorescence and electron microscopy were used to investigate distribution and intracellular trafficking of HDL and its associated cholesterol using fluorescent surrogates (bodipy-cholesterol and bodipy-cholesteryl oleate, cytochemical labels and fluorochromes including horseradish peroxidase and Alexa Fluor® 568. Uptake and intracellular transport of HDL were demonstrated after internalization periods from 0.5 to 4 hours. In case of HDL-Alexa Fluor® 568, bodipy-cholesterol and bodipy-cholesteryl oleate, a photooxidation method was carried out. HDL-specific reaction products were present in invaginations of the plasma membrane at each time of treatment within endocytic vesicles, in multivesicular bodies and at longer periods of uptake, also in lysosomes. Some HDL-positive endosomes were arranged in form of "strings of pearl"- like structures. HDL-positive multivesicular bodies exhibited intensive staining of limiting and vesicular membranes. Multivesicular bodies of HDL-Alexa Fluor® 568-treated EPCs showed multilamellar intra-vacuolar membranes. At all periods of treatment, labeled endocytic vesicles and organelles were apparent close to the cell surface and in perinuclear areas around the Golgi apparatus. No HDL-related particles could be demonstrated close to its cisterns. Electron tomographic reconstructions showed an accumulation of HDL-containing endosomes close to the trans-Golgi-network. HDL-derived bodipy-cholesterol was localized in endosomal vesicles, multivesicular bodies, lysosomes and in many of the stacked Golgi cisternae and the trans-Golgi-network Internalized HDL-derived bodipy-cholesteryl oleate was channeled into the lysosomal

  10. A novel planar flow cell for studies of biofilm heterogeneity and flow-biofilm interactions

    Science.gov (United States)

    Zhang, Wei; Sileika, Tadas S.; Chen, Cheng; Liu, Yang; Lee, Jisun; Packman, Aaron I.

    2012-01-01

    Biofilms are microbial communities growing on surfaces, and are ubiquitous in nature, in bioreactors, and in human infection. Coupling between physical, chemical, and biological processes is known to regulate the development of biofilms; however, current experimental systems do not provide sufficient control of environmental conditions to enable detailed investigations of these complex interactions. We developed a novel planar flow cell that supports biofilm growth under complex two-dimensional fluid flow conditions. This device provides precise control of flow conditions and can be used to create well-defined physical and chemical gradients that significantly affect biofilm heterogeneity. Moreover, the top and bottom of the flow chamber are transparent, so biofilm growth and flow conditions are fully observable using non-invasive confocal microscopy and high-resolution video imaging. To demonstrate the capability of the device, we observed the growth of Pseudomonas aeruginosa biofilms under imposed flow gradients. We found a positive relationship between patterns of fluid velocity and biofilm biomass because of faster microbial growth under conditions of greater local nutrient influx, but this relationship eventually reversed because high hydrodynamic shear leads to the detachment of cells from the surface. These results reveal that flow gradients play a critical role in the development of biofilm communities. By providing new capability for observing biofilm growth, solute and particle transport, and net chemical transformations under user-specified environmental gradients, this new planar flow cell system has broad utility for studies of environmental biotechnology and basic biofilm microbiology, as well as applications in bioreactor design, environmental engineering, biogeochemistry, geomicrobiology, and biomedical research. PMID:21656713

  11. Comparison of low-density lipoprotein obtained from the Friedewald formula and new formulae in a heterogeneous population

    Directory of Open Access Journals (Sweden)

    César Augusto Guevara-Cuéllar

    2010-12-01

    Full Text Available Introduction: Although the levels of low-density lipoprotein (LDL-C should ideally be determined by beta quantification or enzymatic methods, there are limitations in developing countries. The goal of this study is to compare LDL-C obtained through three formulae (LDL-Cnf with LDL-C obtained through the Friedewald formula (LDL-Cf using LDL-C through enzymatic methods as the most-accepted reference method in clinical practice (LDL-Cr.Methods: A concordance study was carried out in a reference laboratory in Cali, Colombia. The three formulae were (mg/dl: Men with triglycerides under 400 mg/dl: LDL-C = Total Cholesterol (TC - triglycerides (TG /6.5 - 45; men with triglycerides equal to or greater than 400 mg/dl: LDL-C = (TC - (TG / 7 -50 and women: LDL-C = (TC-(TG /6.5 - 70.Results: Three-hundred fifteen values were obtained of which 53% were for women. The mean age and LDL-Cr were 54 years (±15.8 and 112.1 mg/dl (±32.5, respectively. The median (interquartile range, mg/dl of TC, high-density lipoprotein (HDL-C and TG were 204 mg/dl (171-229, 51 mg/dl (41-61, and 156 mg/dl (99-237, respectively. There were no differences between mean values of LDL-Cr and LDL-Cnf (113.48 vs. 112.67 mg/dl; p=0.45. The intraclass correlation coefficient among LDL-Cr and LDL-Cf and LDL-Cnf were high (R=0.93 and 0.92, respectively. The correlation between LDL-Cf and LDL-Cnf was 0.95. There is no difference between the areas under the receiver operating characteristic (ROC curve with the level of LDL-Cr at 160 mg/dl for LDL-Cnf and LDL-Cf. (0.94 vs. 0.93; p=0.27.Conclusion: There is high concordance between LDL-Cf and LDL-Cnf. These formulae could be an alternative when there are limitations to determine LDL-C because of the lack of enzymatic methods or through Friedewald formula due to the absence of HDL-C.

  12. Influence of landscape heterogeneity on spatial patterns of wood productivity, wood specific density and above ground biomass in Amazonia

    Science.gov (United States)

    Anderson, L. O.; Malhi, Y.; Ladle, R. J.; Aragão, L. E. O. C.; Shimabukuro, Y.; Phillips, O. L.; Baker, T.; Costa, A. C. L.; Espejo, J. S.; Higuchi, N.; Laurance, W. F.; López-González, G.; Monteagudo, A.; Núñez-Vargas, P.; Peacock, J.; Quesada, C. A.; Almeida, S.

    2009-09-01

    Long-term studies using the RAINFOR network of forest plots have generated significant insights into the spatial and temporal dynamics of forest carbon cycling in Amazonia. In this work, we map and explore the landscape context of several major RAINFOR plot clusters using Landsat ETM+ satellite data. In particular, we explore how representative the plots are of their landscape context, and test whether bias in plot location within landscapes may be influencing the regional mean values obtained for important forest biophysical parameters. Specifically, we evaluate whether the regional variations in wood productivity, wood specific density and above ground biomass derived from the RAINFOR network could be driven by systematic and unintentional biases in plot location. Remote sensing data covering 45 field plots were aggregated to generate landscape maps to identify the specific physiognomy of the plots. In the Landsat ETM+ data, it was possible to spectrally differentiate three types of terra firme forest, three types of forests over Paleovarzea geomorphologycal formation, two types of bamboo-dominated forest, palm forest, Heliconia monodominant vegetation, swamp forest, disturbed forests and land use areas. Overall, the plots were generally representative of the forest physiognomies in the landscape in which they are located. Furthermore, the analysis supports the observed regional trends in those important forest parameters. This study demonstrates the utility of landscape scale analysis of forest physiognomies for validating and supporting the finds of plot based studies. Moreover, the more precise geolocation of many key RAINFOR plot clusters achieved during this research provides important contextual information for studies employing the RAINFOR database.

  13. Influence of landscape heterogeneity on spatial patterns of wood productivity, wood specific density and above ground biomass in Amazonia

    Directory of Open Access Journals (Sweden)

    L. O. Anderson

    2009-09-01

    Full Text Available Long-term studies using the RAINFOR network of forest plots have generated significant insights into the spatial and temporal dynamics of forest carbon cycling in Amazonia. In this work, we map and explore the landscape context of several major RAINFOR plot clusters using Landsat ETM+ satellite data. In particular, we explore how representative the plots are of their landscape context, and test whether bias in plot location within landscapes may be influencing the regional mean values obtained for important forest biophysical parameters. Specifically, we evaluate whether the regional variations in wood productivity, wood specific density and above ground biomass derived from the RAINFOR network could be driven by systematic and unintentional biases in plot location. Remote sensing data covering 45 field plots were aggregated to generate landscape maps to identify the specific physiognomy of the plots. In the Landsat ETM+ data, it was possible to spectrally differentiate three types of terra firme forest, three types of forests over Paleovarzea geomorphologycal formation, two types of bamboo-dominated forest, palm forest, Heliconia monodominant vegetation, swamp forest, disturbed forests and land use areas. Overall, the plots were generally representative of the forest physiognomies in the landscape in which they are located. Furthermore, the analysis supports the observed regional trends in those important forest parameters. This study demonstrates the utility of landscape scale analysis of forest physiognomies for validating and supporting the finds of plot based studies. Moreover, the more precise geolocation of many key RAINFOR plot clusters achieved during this research provides important contextual information for studies employing the RAINFOR database.

  14. Influence of landscape heterogeneity on spatial patterns of wood productivity, wood specific density and above ground biomass in Amazonia

    Directory of Open Access Journals (Sweden)

    L. O. Anderson

    2009-02-01

    Full Text Available Long-term studies using the RAINFOR network of forest plots have generated significant insights into the spatial and temporal dynamics of forest carbon cycling in Amazonia. In this work, we map and explore the landscape context of several major RAINFOR plot clusters using Landsat ETM+ satellite data. In particular, we explore how representative the plots are of their landscape context, and test whether bias in plot location within landscapes may be influencing the regional mean values obtained for important forest biophysical parameters. Specifically, we evaluate whether the regional variations in wood productivity, wood specific density and above ground biomass derived from the RAINFOR network could be driven by systematic and unintentional biases in plot location. Remote sensing data covering 45 field plots were aggregated to generate landscape maps to identify the specific physiognomy of the plots. In the Landsat ETM+ data, it was possible to spectrally differentiate three types of terra firme forest, three types of alluvial terrain forest, two types of bamboo-dominated forest, palm forest, Heliconia monodominant vegetation, swamp forest, disturbed forests and land use areas. Overall, the plots were generally representative of the forest physiognomies in the landscape in which they are located. Furthermore, the analysis supports the observed regional trends in those important forest parameters. This study demonstrates the utility of landscape scale analysis of forest physiognomies for validating and supporting the finds of plot based studies. Moreover, the more precise geolocation of many key RAINFOR plot clusters achieved during this research provides important contextual information for studies employing the RAINFOR database.

  15. Dose calculation models for proton treatment planning using a dynamic beam delivery system: an attempt to include density heterogeneity effects in the analytical dose calculation

    International Nuclear Information System (INIS)

    The gantry for proton radiotherapy at the Paul Scherrer Institute (PSI) is designed specifically for the spot-scanning technique. Use of this technique to its full potential requires dose calculation algorithms which are capable of precisely simulating each scanned beam individually. Different specialized analytical dose calculations have been developed, which attempt to model the effects of density heterogeneities in the patient's body on the dose. Their accuracy has been evaluated by a comparison with Monte Carlo calculated dose distributions in the case of a simple geometrical density interface parallel to the beam and typical anatomical situations. A specialized ray casting model which takes range dilution effects (broadening of the spectrum of proton ranges) into account has been found to produce results of good accuracy. This algorithm can easily be implemented in the iterative optimization procedure used for the calculation of the optimal contribution of each individual scanned pencil beam. In most cases an elemental pencil beam dose calculation has been found to be most accurate. Due to the long computing time, this model is currently used only after the optimization procedure as an alternative method of calculating the dose. (author)

  16. Information in a Network of Neuronal Cells: Effect of Cell Density and Short-Term Depression

    KAUST Repository

    Onesto, Valentina

    2016-05-10

    Neurons are specialized, electrically excitable cells which use electrical to chemical signals to transmit and elaborate information. Understanding how the cooperation of a great many of neurons in a grid may modify and perhaps improve the information quality, in contrast to few neurons in isolation, is critical for the rational design of cell-materials interfaces for applications in regenerative medicine, tissue engineering, and personalized lab-on-a-chips. In the present paper, we couple an integrate-and-fire model with information theory variables to analyse the extent of information in a network of nerve cells. We provide an estimate of the information in the network in bits as a function of cell density and short-term depression time. In the model, neurons are connected through a Delaunay triangulation of not-intersecting edges; in doing so, the number of connecting synapses per neuron is approximately constant to reproduce the early time of network development in planar neural cell cultures. In simulations where the number of nodes is varied, we observe an optimal value of cell density for which information in the grid is maximized. In simulations in which the posttransmission latency time is varied, we observe that information increases as the latency time decreases and, for specific configurations of the grid, it is largely enhanced in a resonance effect.

  17. Information in a Network of Neuronal Cells: Effect of Cell Density and Short-Term Depression

    Science.gov (United States)

    Onesto, Valentina; Cosentino, Carlo; Di Fabrizio, Enzo; Cesarelli, Mario; Amato, Francesco; Gentile, Francesco

    2016-01-01

    Neurons are specialized, electrically excitable cells which use electrical to chemical signals to transmit and elaborate information. Understanding how the cooperation of a great many of neurons in a grid may modify and perhaps improve the information quality, in contrast to few neurons in isolation, is critical for the rational design of cell-materials interfaces for applications in regenerative medicine, tissue engineering, and personalized lab-on-a-chips. In the present paper, we couple an integrate-and-fire model with information theory variables to analyse the extent of information in a network of nerve cells. We provide an estimate of the information in the network in bits as a function of cell density and short-term depression time. In the model, neurons are connected through a Delaunay triangulation of not-intersecting edges; in doing so, the number of connecting synapses per neuron is approximately constant to reproduce the early time of network development in planar neural cell cultures. In simulations where the number of nodes is varied, we observe an optimal value of cell density for which information in the grid is maximized. In simulations in which the posttransmission latency time is varied, we observe that information increases as the latency time decreases and, for specific configurations of the grid, it is largely enhanced in a resonance effect.

  18. Information in a Network of Neuronal Cells: Effect of Cell Density and Short-Term Depression

    Directory of Open Access Journals (Sweden)

    Valentina Onesto

    2016-01-01

    Full Text Available Neurons are specialized, electrically excitable cells which use electrical to chemical signals to transmit and elaborate information. Understanding how the cooperation of a great many of neurons in a grid may modify and perhaps improve the information quality, in contrast to few neurons in isolation, is critical for the rational design of cell-materials interfaces for applications in regenerative medicine, tissue engineering, and personalized lab-on-a-chips. In the present paper, we couple an integrate-and-fire model with information theory variables to analyse the extent of information in a network of nerve cells. We provide an estimate of the information in the network in bits as a function of cell density and short-term depression time. In the model, neurons are connected through a Delaunay triangulation of not-intersecting edges; in doing so, the number of connecting synapses per neuron is approximately constant to reproduce the early time of network development in planar neural cell cultures. In simulations where the number of nodes is varied, we observe an optimal value of cell density for which information in the grid is maximized. In simulations in which the posttransmission latency time is varied, we observe that information increases as the latency time decreases and, for specific configurations of the grid, it is largely enhanced in a resonance effect.

  19. Information in a Network of Neuronal Cells: Effect of Cell Density and Short-Term Depression.

    Science.gov (United States)

    Onesto, Valentina; Cosentino, Carlo; Di Fabrizio, Enzo; Cesarelli, Mario; Amato, Francesco; Gentile, Francesco

    2016-01-01

    Neurons are specialized, electrically excitable cells which use electrical to chemical signals to transmit and elaborate information. Understanding how the cooperation of a great many of neurons in a grid may modify and perhaps improve the information quality, in contrast to few neurons in isolation, is critical for the rational design of cell-materials interfaces for applications in regenerative medicine, tissue engineering, and personalized lab-on-a-chips. In the present paper, we couple an integrate-and-fire model with information theory variables to analyse the extent of information in a network of nerve cells. We provide an estimate of the information in the network in bits as a function of cell density and short-term depression time. In the model, neurons are connected through a Delaunay triangulation of not-intersecting edges; in doing so, the number of connecting synapses per neuron is approximately constant to reproduce the early time of network development in planar neural cell cultures. In simulations where the number of nodes is varied, we observe an optimal value of cell density for which information in the grid is maximized. In simulations in which the posttransmission latency time is varied, we observe that information increases as the latency time decreases and, for specific configurations of the grid, it is largely enhanced in a resonance effect. PMID:27403421

  20. High-density lipoprotein, mitochondrial dysfunction and cell survival mechanisms.

    Science.gov (United States)

    White, C Roger; Giordano, Samantha; Anantharamaiah, G M

    2016-09-01

    Ischemic injury is associated with acute myocardial infarction, percutaneous coronary intervention, coronary artery bypass grafting and open heart surgery. The timely re-establishment of blood flow is critical in order to minimize cardiac complications. Reperfusion after a prolonged ischemic period, however, can induce severe cardiomyocyte dysfunction with mitochondria serving as a major target of ischemia/reperfusion (I/R) injury. An increase in the formation of reactive oxygen species (ROS) induces damage to mitochondrial respiratory complexes leading to uncoupling of oxidative phosphorylation. Mitochondrial membrane perturbations also contribute to calcium overload, opening of the mitochondrial permeability transition pore (mPTP) and the release of apoptotic mediators into the cytoplasm. Clinical and experimental studies show that ischemic preconditioning (ICPRE) and postconditioning (ICPOST) attenuate mitochondrial injury and improve cardiac function in the context of I/R injury. This is achieved by the activation of two principal cell survival cascades: 1) the Reperfusion Injury Salvage Kinase (RISK) pathway; and 2) the Survivor Activating Factor Enhancement (SAFE) pathway. Recent data suggest that high density lipoprotein (HDL) mimics the effects of conditioning protocols and attenuates myocardial I/R injury via activation of the RISK and SAFE signaling cascades. In this review, we discuss the roles of apolipoproteinA-I (apoA-I), the major protein constituent of HDL, and sphingosine 1-phosphate (S1P), a lysosphingolipid associated with small, dense HDL particles as mediators of cardiomyocyte survival. Both apoA-I and S1P exert an infarct-sparing effect by preventing ROS-dependent injury and inhibiting the opening of the mPTP. PMID:27150975

  1. Comparative evaluation of optical methods and conventional isotope techniques for the detection of insulin receptors in heterogenous cell systems

    International Nuclear Information System (INIS)

    The findings of studies using radioactively labelled (I-125) insulin to characterise its binding to various heterogenous cell systems had led to a classification of the relevant receptors with those of high affinity and low capacity or vice versa. This, in turn, raised questions as to the binding properties of each individual cell or cell material of a heterogenous nature. Apparently homogenous (lymphocytes) and heterogenous (blood and islet cells) cell populations were investigated on the basis of various techniques for the separate evaluation of individual cells, which were cytofluorometry using FITC insulin and the analysis of gold insulin under the electron microscope. For the association kinetics and equilibration analysis or affinity and receptor quantity a radioactive tracer and light microscope were used. Insulin was shown to bind to erythrocytes, reticulocytes, monocytes and lymphocytes and this result finds confirmation in the relevant literature. Furthermore, binding parameters could be determined for isolated islet cells. Cytofluorometry pointed to the fact that the insulin receptors of an apparently homogenous cell system differed in affinity and number and permitted the use of a multiple parameter procedure. Thus, it holds out promise as a method to be routinely used in the clinical diagnosis of binding parameters, without requiring previous separation procedures that are complicated or involve a loss of material. Transmission electron microscopy permitted conclusions to be drawn as to the type of cell to which insulin is attached. Owing to the use of gold insulin it was possible to throw some light on the factors determining the fate of membrane-bound insulin during its uptake into the cell. (TRV)

  2. Fractal heterogeneity in minimal matrix models of scars modulates stiff-niche stem-cell responses via nuclear exit of a mechanorepressor

    Science.gov (United States)

    Dingal, P. C. Dave P.; Bradshaw, Andrew M.; Cho, Sangkyun; Raab, Matthew; Buxboim, Amnon; Swift, Joe; Discher, Dennis E.

    2015-09-01

    Scarring is a long-lasting problem in higher animals, and reductionist approaches could aid in developing treatments. Here, we show that copolymerization of collagen I with polyacrylamide produces minimal matrix models of scars (MMMS), in which fractal-fibre bundles segregate heterogeneously to the hydrogel subsurface. Matrix stiffens locally--as in scars--while allowing separate control over adhesive-ligand density. The MMMS elicits scar-like phenotypes from mesenchymal stem cells (MSCs): cells spread and polarize quickly, increasing nucleoskeletal lamin-A yet expressing the `scar marker' smooth muscle actin (SMA) more slowly. Surprisingly, expression responses to MMMS exhibit less cell-to-cell noise than homogeneously stiff gels. Such differences from bulk-average responses arise because a strong SMA repressor, NKX2.5, slowly exits the nucleus on rigid matrices. NKX2.5 overexpression overrides rigid phenotypes, inhibiting SMA and cell spreading, whereas cytoplasm-localized NKX2.5 mutants degrade in well-spread cells. MSCs thus form a `mechanical memory' of rigidity by progressively suppressing NKX2.5, thereby elevating SMA in a scar-like state.

  3. Association of lecithin-cholesterol acyltransferase activity measured as a serum cholesterol esterification rate and low-density lipoprotein heterogeneity with cardiovascular risk: a cross-sectional study.

    Science.gov (United States)

    Tani, Shigemasa; Takahashi, Atsuhiko; Nagao, Ken; Hirayama, Atsushi

    2016-06-01

    The cholesterol-esterifying enzyme, lecithin-cholesterol acyltransferase (LCAT), is believed to play a key role in reverse cholesterol transport. However, recent investigations have demonstrated that higher LCAT activity levels increase the formation of triglyceride (TG)-rich lipoproteins (TRLs) and atherogenesis. We hypothesized that higher LCAT activity measured as a serum cholesterol esterification rate by the endogenous substrate method might increase the formation of TRLs and thereby alter low-density lipoprotein (LDL) heterogeneity. The estimated LDL particle size [relative LDL migration (LDL-Rm)] was measured by polyacrylamide gel electrophoresis with the LipoPhor system (Joko, Tokyo, Japan) in 538 consecutive patients with at least risk factor for atherosclerosis. Multivariate regression analysis after adjustments for traditional risk factors identified elevated TRL-related marker (TG, remnant-like particle cholesterol, apolipoprotein C-II, and apolipoprotein C-III) levels as independent predictors of smaller-sized LDL particle size, both in the overall subject population and in the subset of patients with serum LDL cholesterol levels of <100 mg/dL. Area under the receiver operating characteristic curve of the LCAT activity (0.79; sensitivity 60 %; specificity 84.8 %) was observed for the evaluation of the indicators of an LDL-Rm value of ≥0.40, which suggests the presence of large amounts of small-dense LDL. The results lend support to the hypothesis that increased LCAT activity may be associated with increased formation of TRLs, leading to a reduction in LDL particle size. Therefore, to reduce the risk of atherosclerotic cardiovascular disease, it may be of importance to pay attention not only to a quantitative change in the serum LDL-C, but also to the LCAT activity which is possibly associated with LDL heterogeneity. PMID:25894629

  4. Metastatic spread in patients with non-small cell lung cancer is associated with a reduced density of tumor-infiltrating T cells.

    Science.gov (United States)

    Müller, Philipp; Rothschild, Sacha I; Arnold, Walter; Hirschmann, Petra; Horvath, Lukas; Bubendorf, Lukas; Savic, Spasenija; Zippelius, Alfred

    2016-01-01

    Tumor-infiltrating lymphocytes play an important role in cell-mediated immune destruction of cancer cells and tumor growth control. We investigated the heterogeneity of immune cell infiltrates between primary non-small cell lung carcinomas (NSCLC) and corresponding metastases. Formalin-fixed, paraffin-embedded primary tumors and corresponding metastases from 34 NSCLC patients were analyzed by immunohistochemistry for CD4, CD8, CD11c, CD68, CD163 and PD-L1. The percentage of positively stained cells within the stroma and tumor cell clusters was recorded and compared between primary tumors and metastases. We found significantly fewer CD4(+) and CD8(+) T cells within tumor cell clusters as compared with the stromal compartment, both in primary tumors and corresponding metastases. CD8(+) T cell counts were significantly lower in metastatic lesions than in the corresponding primary tumors, both in the stroma and the tumor cell islets. Of note, the CD8/CD4 ratio was significantly reduced in metastatic lesions compared with the corresponding primary tumors in tumor cell islets, but not in the stroma. We noted significantly fewer CD11c(+) cells and CD68(+) as well as CD163(+) macrophages in tumor cell islets compared with the tumor stroma, but no difference between primary and metastatic lesions. Furthermore, the CD8/CD68 ratio was higher in primary tumors than in the corresponding metastases. We demonstrate a differential pattern of immune cell infiltration in matched primary and metastatic NSCLC lesions, with a significantly lower density of CD8(+) T cells in metastatic lesions compared with the primary tumors. The lower CD8/CD4 and CD8/CD68 ratios observed in metastases indicate a rather tolerogenic and tumor-promoting microenvironment at the metastatic site. PMID:26541588

  5. Is manual counting of corneal endothelial cell density in eye banks still acceptable? The French experience

    OpenAIRE

    Thuret, G; Manissolle, C; Acquart, S.; Petit, J-C Le; Maugery, J; Campos-Guyotat, L; Doughty, M J; Gain, P

    2003-01-01

    Aim: To examine the differences in manual endothelial cell counting methods in French eye banks and to analyse whether these differences could explain some substantial discrepancies observed in endothelial cell density (ECD) for corneas made available for transplant.

  6. Biofunctionalized magnetic nanospheres-based cell sorting strategy for efficient isolation, detection and subtype analyses of heterogeneous circulating hepatocellular carcinoma cells.

    Science.gov (United States)

    Chen, Lan; Wu, Ling-Ling; Zhang, Zhi-Ling; Hu, Jiao; Tang, Man; Qi, Chu-Bo; Li, Na; Pang, Dai-Wen

    2016-11-15

    Hepatocellular carcinoma (HCC) is an awful threat to human health. Early-stage HCC may be detected by isolation of circulating tumor cells (CTCs) from peripheral blood samples, which is beneficial to the diagnosis and therapy. However, the extreme rarity and high heterogeneity of HCC CTCs have been restricting the relevant research. To achieve an efficient isolation, reliable detection and subtype analyses of heterogeneous HCC CTCs, herein, we present a cell sorting strategy based on anti-CD45 antibody-modified magnetic nanospheres. By this strategy, leukocyte depletion efficiency was up to 99.9% within 30min in mimic clinical samples, and the purity of the spiked HCC cells was improved 265-317-fold. Besides, the isolated HCC cells remained viable at 92.3% and could be directly recultured. Moreover, coupling the convenient, fast and effective cell sorting strategy with specific ICC identification via biomarkers AFP and GPC3, HCC CTCs were detectable in peripheral blood samples, showing the potential for HCC CTC detection in clinic. Notably, this immunomagnetic cell sorting strategy enabled isolating more heterogeneous HCC cells compared with the established EpCAM-based methods, and further achieved characterization of three different CTC subtypes from one clinical HCC blood sample, which may assist clinical HCC analyses such as prognosis or personalized treatment. PMID:27240010

  7. Tumour heterogeneity in non-small cell lung carcinoma assessed by CT texture analysis: a potential marker of survival

    Energy Technology Data Exchange (ETDEWEB)

    Ganeshan, Balaji; Miles, Ken [Brighton and Sussex Medical School, Clinical Imaging Sciences Centre, Division of Clinical and Laboratory Investigation, Brighton, East Sussex (United Kingdom); Panayiotou, Elleny; Burnand, Kate [Brighton and Sussex University Hospitals NHS Trust, Brighton (United Kingdom); Dizdarevic, Sabina [Brighton and Sussex University Hospitals NHS Trust, Department of Nuclear Medicine, Royal Sussex County Hospital, Brighton (United Kingdom)

    2012-04-15

    To establish the potential for tumour heterogeneity in non-small cell lung cancer (NSCLC) as assessed by CT texture analysis (CTTA) to provide an independent marker of survival for patients with NSCLC. Tumour heterogeneity was assessed by CTTA of unenhanced images of primary pulmonary lesions from 54 patients undergoing {sup 18}F-fluorodeoxyglucose (FDG) PET-CT for staging of NSCLC. CTTA comprised image filtration to extract fine, medium and coarse features with quantification of the distribution of pixel values (uniformity) within the filtered images. Receiver operating characteristics identified thresholds for PET and CTTA parameters that were related to patient survival using Kaplan-Meier analysis. The median (range) survival was 29.5 (1-38) months. 24, 10, 14 and 6 patients had tumour stages I, II, III and IV respectively. PET stage and tumour heterogeneity assessed by CTTA were significant independent predictors of survival (PET stage: Odds ratio 3.85, 95% confidence limits 0.9-8.09, P = 0.002; CTTA: Odds ratio 56.4, 95% confidence limits 4.79-666, p = 0.001). SUV was not a significantly associated with survival. Assessment of tumour heterogeneity by CTTA of non-contrast enhanced images has the potential for to provide a novel, independent predictor of survival for patients with NSCLC. (orig.)

  8. Resolution of heterogeneous fluorescence emission signals and decay lifetime measurement on fluorochrome-labeled cells by phase-sensitive FCM

    Energy Technology Data Exchange (ETDEWEB)

    Steinkamp, J.A.; Crissman, H.A.

    1993-01-01

    A phase-sensitive flow cytometer has been developed to resolve signals from heterogeneous fluorescence emission spectra and quantify fluorescence decay times on cells labeled with fluorescent dyes. This instrument combines flow cytometry (FCM) and fluorescence spectroscopy measurement principles to provide unique capabilities for making phase-resolved measurements on single cells in flow, while preserving conventional FCM measurement capabilities. Stained cells are analyzed as they pass through an intensity-modulated (sinusoid) laser excitation beam. Fluorescence is measured orthogonally using a s barrier filter to block scattered laser excitation light, and a photomultiplier tube detector output signals, which are shifted in phase from a reference signal and amplitude demodulated, are processed by phase-sensitive detection electronics to resolve signals from heterogeneous emissions and quantify decay lifetimes directly. The output signals are displayed as frequency distribution histograms and bivariate diagrams using a computer-based data acquisition system. Results have demonstrated signal phase shift, amplitude demodulation, and average measurement of fluorescence lifetimes on stained cells; a detection limit threshold of 300 to 500 fluorescein isothiocyanate (FITC); fluorescence measurement precision of 1.3% on alignment fluorospheres and 3.4% on propidium iodide (PI)-stained cells; the resolution of PI and FITC signals from cells stainedin combination with PI and FITC, based on differences in their decay lifetimes; and the ability to measure single decay nines by the two-phase, phase comparator, method.

  9. Resolution of heterogeneous fluorescence emission signals and decay lifetime measurement on fluorochrome-labeled cells by phase-sensitive FCM

    Energy Technology Data Exchange (ETDEWEB)

    Steinkamp, J.A.; Crissman, H.A.

    1993-02-01

    A phase-sensitive flow cytometer has been developed to resolve signals from heterogeneous fluorescence emission spectra and quantify fluorescence decay times on cells labeled with fluorescent dyes. This instrument combines flow cytometry (FCM) and fluorescence spectroscopy measurement principles to provide unique capabilities for making phase-resolved measurements on single cells in flow, while preserving conventional FCM measurement capabilities. Stained cells are analyzed as they pass through an intensity-modulated (sinusoid) laser excitation beam. Fluorescence is measured orthogonally using a s barrier filter to block scattered laser excitation light, and a photomultiplier tube detector output signals, which are shifted in phase from a reference signal and amplitude demodulated, are processed by phase-sensitive detection electronics to resolve signals from heterogeneous emissions and quantify decay lifetimes directly. The output signals are displayed as frequency distribution histograms and bivariate diagrams using a computer-based data acquisition system. Results have demonstrated signal phase shift, amplitude demodulation, and average measurement of fluorescence lifetimes on stained cells; a detection limit threshold of 300 to 500 fluorescein isothiocyanate (FITC); fluorescence measurement precision of 1.3% on alignment fluorospheres and 3.4% on propidium iodide (PI)-stained cells; the resolution of PI and FITC signals from cells stainedin combination with PI and FITC, based on differences in their decay lifetimes; and the ability to measure single decay nines by the two-phase, phase comparator, method.

  10. Chromogranin A cell density in the rectum of patients with irritable bowel syndrome

    OpenAIRE

    El-Salhy, M.; Mazzawi, T; Gundersen, D.; Hausken, T.

    2012-01-01

    In a previous study, chromogranin A (CgA) cell density in the colon of patients with irritable bowel syndrome (IBS) was found to be reduced. It has been suggested that intestinal CgA cell density may be used as a marker for the diagnosis of IBS. The rectum harbours a larger number of large intestinal endocrine cells and is more accessible for biopsies than the colon. The present study aimed at determining the CgA cell density in the rectum of IBS patients. A total of 47 patients with IBS that...

  11. Estimation of current density distribution of PAFC by analysis of cell exhaust gas

    Energy Technology Data Exchange (ETDEWEB)

    Kato, S.; Seya, A. [Fuji Electric Co., Ltd., Ichihara-shi (Japan); Asano, A. [Fuji Electric Corporate, Ltd., Yokosuka-shi (Japan)

    1996-12-31

    To estimate distributions of Current densities, voltages, gas concentrations, etc., in phosphoric acid fuel cell (PAFC) stacks, is very important for getting fuel cells with higher quality. In this work, we leave developed a numerical simulation tool to map out the distribution in a PAFC stack. And especially to Study Current density distribution in the reaction area of the cell, we analyzed gas composition in several positions inside a gas outlet manifold of the PAFC stack. Comparing these measured data with calculated data, the current density distribution in a cell plane calculated by the simulation, was certified.

  12. Diffuse large B-cell lymphoma patient-derived xenograft models capture the molecular and biological heterogeneity of the disease.

    Science.gov (United States)

    Chapuy, Bjoern; Cheng, Hongwei; Watahiki, Akira; Ducar, Matthew D; Tan, Yuxiang; Chen, Linfeng; Roemer, Margaretha G M; Ouyang, Jing; Christie, Amanda L; Zhang, Liye; Gusenleitner, Daniel; Abo, Ryan P; Farinha, Pedro; von Bonin, Frederike; Thorner, Aaron R; Sun, Heather H; Gascoyne, Randy D; Pinkus, Geraldine S; van Hummelen, Paul; Wulf, Gerald G; Aster, Jon C; Weinstock, David M; Monti, Stefano; Rodig, Scott J; Wang, Yuzhuo; Shipp, Margaret A

    2016-05-01

    Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous disease defined by transcriptional classifications, specific signaling and survival pathways, and multiple low-frequency genetic alterations. Preclinical model systems that capture the genetic and functional heterogeneity of DLBCL are urgently needed. Here, we generated and characterized a panel of large B-cell lymphoma (LBCL) patient-derived xenograft (PDX) models, including 8 that reflect the immunophenotypic, transcriptional, genetic, and functional heterogeneity of primary DLBCL and 1 that is a plasmablastic lymphoma. All LBCL PDX models were subjected to whole-transcriptome sequencing to classify cell of origin and consensus clustering classification (CCC) subtypes. Mutations and chromosomal rearrangements were evaluated by whole-exome sequencing with an extended bait set. Six of the 8 DLBCL models were activated B-cell (ABC)-type tumors that exhibited ABC-associated mutations such as MYD88, CD79B, CARD11, and PIM1. The remaining 2 DLBCL models were germinal B-cell type, with characteristic alterations of GNA13, CREBBP, and EZH2, and chromosomal translocations involving IgH and either BCL2 or MYC Only 25% of the DLBCL PDX models harbored inactivating TP53 mutations, whereas 75% exhibited copy number alterations of TP53 or its upstream modifier, CDKN2A, consistent with the reported incidence and type of p53 pathway alterations in primary DLBCL. By CCC criteria, 6 of 8 DLBCL PDX models were B-cell receptor (BCR)-type tumors that exhibited selective surface immunoglobulin expression and sensitivity to entospletinib, a recently developed spleen tyrosine kinase inhibitor. In summary, we have established and characterized faithful PDX models of DLBCL and demonstrated their usefulness in functional analyses of proximal BCR pathway inhibition. PMID:26773040

  13. Optimization of Seeding Density in Microencapsulated Recombinant CHO Cell Culture

    OpenAIRE

    Zhang, Ying; Zhou, Jing; Zhang, Xulang; Yu, Weiting; Guo, Xin; Wang, Wei; Ma, Xiaojun

    2008-01-01

    Microencapsulation technology is an alternative large-scale mammalian cell culture method. The semi-permeable membrane of the microcapsule allows free diffusion of nutrients, oxygen and toxic metabolites to support cell growth, and the microcapsule membrane can protect the cells from the mechanical damage of shear forces associated with agitation and aeration. Many polymers have been used to make microcapsules, such as chitosan, polyacrylates, alginate, polyamino acids, and polyamides. One of...

  14. Single-Cell Gene Expression Analyses Reveal Heterogeneous Responsiveness of Fetal Innate Lymphoid Progenitors to Notch Signaling

    Directory of Open Access Journals (Sweden)

    Sylvestre Chea

    2016-02-01

    Full Text Available T and innate lymphoid cells (ILCs share some aspects of their developmental programs. However, although Notch signaling is strictly required for T cell development, it is dispensable for fetal ILC development. Constitutive activation of Notch signaling, at the common lymphoid progenitor stage, drives T cell development and abrogates ILC development by preventing Id2 expression. By combining single-cell transcriptomics and clonal culture strategies, we characterize two heterogeneous α4β7-expressing lymphoid progenitor compartments. αLP1 (Flt3+ still retains T cell potential and comprises the global ILC progenitor, while αLP2 (Flt3− consists of ILC precursors that are primed toward the different ILC lineages. Only a subset of αLP2 precursors is sensitive to Notch signaling required for their proliferation. Our study identifies, in a refined manner, the diversity of transitional stages of ILC development, their transcriptional signatures, and their differential dependence on Notch signaling.

  15. Intratumor heterogeneity and chemotherapy-induced changes in EGFR status in non-small cell lung cancer

    DEFF Research Database (Denmark)

    Jakobsen, Jan Nyrop; Sørensen, Jens Benn

    2012-01-01

    Biomarker expression is increasingly being used to customize treatment in non-small cell lung cancer (NSCLC). The choice of systemic treatment usually depends on biomarker expression in the initial diagnostic biopsy taken before initiation of first-line treatment. Chemotherapy induces DNA damages...... in the tumor cells, and thus, biomarker expression in the tumor after systemic treatment might not be identical to biomarker expression in the diagnostic biopsy. NSCLC is highly heterogeneous and biomarker expression may vary in different areas within the same tumor. This review explores the tumor...

  16. Fluorescence Resonance Energy Transfer between Lipid Probes Detects Nanoscopic Heterogeneity in the Plasma Membrane of Live Cells

    OpenAIRE

    Sengupta, Prabuddha; Holowka, David; Baird, Barbara

    2007-01-01

    Fluorescence resonance energy transfer (FRET) between matched carbocyanine lipid analogs in the plasma membrane outer leaflet of RBL mast cells was used to investigate lateral distributions of lipids and to develop a general method for quantitative measurements of lipid heterogeneity in live cell membranes. FRET measured as fluorescence quenching of long-chain donor probes such as DiO-C18 is greater with long-chain, saturated acceptor probes such as DiI-C16 than with unsaturated or shorter-ch...

  17. Genetic diversity in normal cell populations is the earliest stage of oncogenesis leading to intra-tumor heterogeneity

    Directory of Open Access Journals (Sweden)

    Cory L Howk

    2013-04-01

    Full Text Available Random mutations and epigenetic alterations provide a rich substrate for microevolutionary phenomena to occur in proliferating epithelial tissues. Genetic diversity resulting from random mutations in normal cells is critically important for understanding the genetic basis of oncogenesis. However, evaluation of the cell-specific role of individual (epi-genetic alterations in living tissues is extremely difficult from a direct experimental perspective. We have developed a theoretical model for uterine epithelial cell proliferation. Computational simulations have shown that a base-line mutation rate of two mutations per cell division is sufficient to explain sporadic endometrial cancer as a rare evolutionary consequence with an incidence similar to that reported in SEER data. Simulation of the entire oncogenic process has allowed us to analyze the features of the tumor initiating cells and their clonal expansion. Analysis of the malignant features of individual cancer cells, such as de-differentiation status, proliferation potential, and immortalization status, permits a mathematical characterization of malignancy and a comparison of intra-tumor heterogeneity between individual tumors. We found, under the conditions specified, that cancer stem cells account for approximately 7% of the total cancer cell population. Taken together, our mathematical modeling describes the genetic diversity and evolution in a normal cell population at the early stages of oncogenesis and characterizes intra-tumor heterogeneity. This model has explored the role of accumulation of a large number of genetic alterations in oncogenesis as an alternative to traditional biological approaches emphasizing the driving role of a small number of genetic mutations, and this accumulation, along with environmental factors, has a significant impact on the growth advantage of and selection pressure on individual cancer cells and the resulting tumor composition and progression.

  18. Cell size, number and density in the retina ganglion cell layer of Pekin duck retina at different embryonic age

    Directory of Open Access Journals (Sweden)

    ZUO Shi-Feng

    2008-12-01

    Full Text Available Changes in cell size, number and density of the ganglion cell layer(GCL)of the Pekin duck retina were studied by using the methods of Nissl-staining and Scion Image picture processing at embryonic age day-11,14,17,20,23 and 26. The result indicated that the cells in GCL were small and round uniformly at E11 and E14. The large cells were first found at E17. From E11 to E26, cell size was increased 1.97-fold in the central area (CA and 3.1-fold in the temple periphery (TP, and there was significant difference among all embryonic ages. During the growth and development of embryo, the total number of cells in GCL was increased to 2.03×106 cells at E17, and then decreased significantly with age. Differentiation of the central-peripheral gradient in cell density has been performed at E11. Cell density in CA was up to the maximal value (2.54×104 cells/mm2 at E17 and then decreased. However, cell density was decreased constantly in the peripheral area, especially in TP. In conclusion, E17 is the most important point for the retina during the embryonic developmental of Pekin duck, accompanying changes in cell size, number and density in GCL [Acta Zoologica Sinica 54(6: 1082 – 1088, 2008].

  19. Cells determine cell density using a small protein bound to a unique tissue-specific phospholipid

    Directory of Open Access Journals (Sweden)

    Christopher J. Petzold

    2013-10-01

    Full Text Available Cell density is the critical parameter controlling tendon morphogenesis. Knowing its neighbors allows a cell to regulate correctly its proliferation and collagen production. A missing link to understanding this process is a molecular description of the sensing mechanism. Previously, this mechanism was shown in cell culture to rely on a diffusible factor (SNZR [sensor] with an affinity for the cell layer. This led to purifying conditioned medium over 4 columns and analyzing the final column fractions for band intensity on SDS gels versus biological activity – a 16 kD band strongly correlated between assays. N-terminal sequencing – EPLAVVDL – identified a large gene (424 AA, extremely conserved between chicken and human. In this paper we probe whether this is the correct gene. Can the predicted large protein be cleaved to a smaller protein? EPLAVVDL occurs towards the C-terminus and cleavage would create a small 94 AA protein. This protein would run at ∼10 kD, so what modifications or cofactor binding accounts for its running at 16 kD on SDS gels? This protein has no prominent hydrophobic regions, so can it be secreted? To validate its role, the chicken cDNA for this gene was tagged with myc and his and transfected into a human osteosarcoma cell line (U2OS. U2OS cells expressed the gene but not passively: differentiating into structures resembling spongy bone and expressing alkaline phosphatase, an early bone marker. Intracellularly, two bands were observed by Western blotting: the full length protein and a smaller form (26 kD. Outside the cell, a small band (28 kD was detected, although it was 40% larger than expected, as well as multiple larger bands. These larger forms could be converted to the predicted smaller protein (94 AA + tags by changing salt concentrations and ultrafiltering – releasing a cofactor to the filtrate while leaving a protein factor in the retentate. Using specific degradative enzymes and mass spectrometry, the

  20. Phenotypic and functional heterogeneity of macrophages and dendritic cell subsets in the healthy and atherosclerosis-prone aorta.

    Directory of Open Access Journals (Sweden)

    ElenaVGalkina

    2012-03-01

    Full Text Available Atherosclerosis continues to be the leading cause of cardiovascular disease. Development of atherosclerosis depends on chronic inflammation in the aorta and multiple immune cells are involved in this process. Importantly, resident macrophages and dendritic cells are present within the healthy aorta, but the functions of these cells remain poorly characterized. Local inflammation within the aortic wall promotes the recruitment of monocytes and dendritic cell precursors to the aorta and micro-environmental factors direct the differentiation of these emigrated cells into multiple subsets of macrophages and dendritic cells. Recent data suggest that several populations of macrophages and dendritic cells can co-exist within the aorta. Although the functions of M1, M2, Mox and M4 macrophages are well characterized in vitro, there is a limited set of data on the role of these populations in atherogenesis in vivo. Recent studies on the origin and the potential role of aortic dendritic cells provide novel insights into the biology of aortic dendritic cell subsets and prospective mechanisms of the immune response in atherosclerosis. This review integrates the results of experiments analyzing heterogeneity of dendritic cells and macrophage subsets in healthy and diseased vessels and briefly discusses the known and potential functions of these cells in atherogenesis.

  1. Human peripheral blood mononuclear cells exhibit heterogeneous CD52 expression levels and show differential sensitivity to alemtuzumab mediated cytolysis.

    Directory of Open Access Journals (Sweden)

    Sambasiva P Rao

    Full Text Available Alemtuzumab is a monoclonal antibody that targets cell surface CD52 and is effective in depleting lymphocytes by cytolytic effects in vivo. Although the cytolytic effects of alemtuzumab are dependent on the density of CD52 antigen on cells, there is scant information regarding the expression levels of CD52 on different cell types. In this study, CD52 expression was assessed on phenotypically distinct subsets of lymphoid and myeloid cells in peripheral blood mononuclear cells (PBMCs from normal donors. Results demonstrate that subsets of PBMCs express differing levels of CD52. Quantitative analysis showed that memory B cells and myeloid dendritic cells (mDCs display the highest number while natural killer (NK cells, plasmacytoid dendritic cells (pDCs and basophils have the lowest number of CD52 molecules per cell amongst lymphoid and myeloid cell populations respectively. Results of complement dependent cytolysis (CDC studies indicated that alemtuzumab mediated profound cytolytic effects on B and T cells with minimal effect on NK cells, basophils and pDCs, correlating with the density of CD52 on these cells. Interestingly, despite high CD52 levels, mDCs and monocytes were less susceptible to alemtuzumab-mediated CDC indicating that antigen density alone does not define susceptibility. Additional studies indicated that higher expression levels of complement inhibitory proteins (CIPs on these cells partially contributes to their resistance to alemtuzumab mediated CDC. These results indicate that alemtuzumab is most effective in depleting cells of the adaptive immune system while leaving innate immune cells relatively intact.

  2. Intratumoral Morphologic and Molecular Heterogeneity of Rhabdoid Renal Cell Carcinoma: Challenges for Personalized Therapy

    OpenAIRE

    Singh, Rajesh R.; Murugan, Paari; Patel, Lalit R; Voicu, Horatiu; Yoo, Suk-Young; Majewski, Tadeusz; Mehrotra, Meenakshi; Wani, Khalida; Tannir, Nizar; Karam, Jose A.; Jonasch, Eric; Wood, Christopher G; Creighton, Chad J.; Medeiros, L. Jeffrey; Broaddus, Russell R.

    2015-01-01

    Rhabdoid histology in clear cell renal cell carcinoma is associated with a poor prognosis. The prognosis of patients with clear cell renal cell carcinoma may also be influenced by molecular alterations. The aim of this study was to evaluate the association between histologic features and salient molecular changes in rhabdoid clear cell renal cell carcinoma. We macrodissected the rhabdoid and clear cell epithelioid components from 12 cases of rhabdoid clear cell renal cell carcinoma. We assess...

  3. The density of the cell sap and endoplasm of Nitellopsis and Chara

    Science.gov (United States)

    Wayne, R.; Staves, M. P.

    1991-01-01

    We measured the densities of the cell sap, endoplasm and cell wall of Nitellopsis obtusa and Chara corallina using interference microscopy, refractometry, immersion refractometry, equilibrium sedimentation and chemical microanalysis techniques. These values are important for the determination of many rheological properties of the cytoplasm as well as for understanding buoyancy regulation, dispersal mechanisms and how cells respond to gravity. The average densities of the cell sap, endoplasm and cell wall are 1,006.9, 1,016.7 and 1,371 kg m-3 for Nitellopsis and 1,005.0, 1,013.9, and 1,355.3 kg m-3 for Chara.

  4. Cytogenetic heterogeneity and their serial dynamic changes during acquisition of cytogenetic aberrations in cultured mesenchymal stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jung-Ah [Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul (Korea, Republic of); Im, Kyong Ok; Park, Si Nae; Kwon, Ji Seok [Cancer Research Institute, Seoul National University College of Medicine, Seoul (Korea, Republic of); Kim, Seon Young [Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul (Korea, Republic of); Oh, Keunhee; Lee, Dong-Sup [Laboratory of Immunology and Cancer Biology, Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul (Korea, Republic of); Transplantation Research Institute, Seoul National University College of Medicine, Seoul National University College of Medicine, Seoul (Korea, Republic of); Kim, Min Kyung; Kim, Seong Who [Department of Biochemistry and Molecular Biology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Jang, Mi; Lee, Gene [Lab of Molecular Genetics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul (Korea, Republic of); Oh, Yeon-Mok; Lee, Sang Do [Department of Pulmonary and Critical Care Medicine, Asthma Center and Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Lee, Dong Soon, E-mail: soonlee@snu.ac.kr [Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2015-07-15

    Highlights: • We evaluated cytogenetic aberrations of MSC during culture using G-banding and FISH. • We tracked the quantitative changes of each clone among heterogeneity upon passages. • The changes of cytogenetic profile upon passages were similar to cancer stem cell. - Abstract: To minimize the risk of tumorigenesis in mesenchymal stem cells (MSCs), G-banding analysis is widely used to detect chromosomal aberrations in MSCs. However, a critical limitation of G-banding is that it only reflects the status of metaphase cells, which can represent as few as 0.01% of tested cells. During routine cytogenetic testing in MSCs, we often detect chromosomal aberrations in minor cell populations. Therefore, we aimed to investigate whether such a minority of cells can expand over time or if they ultimately disappear during MSC passaging. We passaged MSCs serially while monitoring quantitative changes for each aberrant clone among heterogeneous MSCs. To investigate the cytogenetic status of interphase cells, which represent the main population, we also performed interphase FISH analysis, in combination with G-banding and telomere length determination. In human adipose tissue-derived MSCs, 4 types of chromosomal aberrations were found during culturing, and in umbilical cord MSCs, 2 types of chromosomal aberrations were observed. Sequential dynamic changes among heterogeneous aberrant clones during passaging were similar to the dynamic changes observed in cancer stem cells during disease progression. Throughout all passages, the quantitative G-banding results were inconsistent with those of the interphase FISH analysis. Interphase FISH revealed hidden aberrations in stem cell populations with normal karyotypes by G-banding analysis. We found that telomere length gradually decreased during passaging until the point at which cytogenetic aberrations appeared. The present study demonstrates that rare aberrant clones at earlier passages can become predominant clones during

  5. Cytogenetic heterogeneity and their serial dynamic changes during acquisition of cytogenetic aberrations in cultured mesenchymal stem cells

    International Nuclear Information System (INIS)

    Highlights: • We evaluated cytogenetic aberrations of MSC during culture using G-banding and FISH. • We tracked the quantitative changes of each clone among heterogeneity upon passages. • The changes of cytogenetic profile upon passages were similar to cancer stem cell. - Abstract: To minimize the risk of tumorigenesis in mesenchymal stem cells (MSCs), G-banding analysis is widely used to detect chromosomal aberrations in MSCs. However, a critical limitation of G-banding is that it only reflects the status of metaphase cells, which can represent as few as 0.01% of tested cells. During routine cytogenetic testing in MSCs, we often detect chromosomal aberrations in minor cell populations. Therefore, we aimed to investigate whether such a minority of cells can expand over time or if they ultimately disappear during MSC passaging. We passaged MSCs serially while monitoring quantitative changes for each aberrant clone among heterogeneous MSCs. To investigate the cytogenetic status of interphase cells, which represent the main population, we also performed interphase FISH analysis, in combination with G-banding and telomere length determination. In human adipose tissue-derived MSCs, 4 types of chromosomal aberrations were found during culturing, and in umbilical cord MSCs, 2 types of chromosomal aberrations were observed. Sequential dynamic changes among heterogeneous aberrant clones during passaging were similar to the dynamic changes observed in cancer stem cells during disease progression. Throughout all passages, the quantitative G-banding results were inconsistent with those of the interphase FISH analysis. Interphase FISH revealed hidden aberrations in stem cell populations with normal karyotypes by G-banding analysis. We found that telomere length gradually decreased during passaging until the point at which cytogenetic aberrations appeared. The present study demonstrates that rare aberrant clones at earlier passages can become predominant clones during

  6. Two parametric cell cycle analyses of plant cell suspension cultures with fragile, isolated nuclei to investigate heterogeneity in growth of batch cultivations.

    Science.gov (United States)

    Haas, Christiane; Hegner, Richard; Helbig, Karsten; Bartels, Kristin; Bley, Thomas; Weber, Jost

    2016-06-01

    Plant cell suspensions are frequently considered to be heterogeneous with respect to growth in terms of progression of the cells through the cell cycle and biomass accumulation. Thus, segregated data of fractions in different cycle phases during cultivation is needed to develop robust production processes. Bromodeoxyuridine (BrdU) incorporation and BrdU-antibodies or 5-ethynyl-2'-deoxyuridine (EdU) click-it chemistry are frequently used to acquire such information. However, their use requires centrifugation steps that cannot be readily applied to sensitive cells, particularly if nuclei have to be extracted from the protective cellular milieu and envelopes for DNA analysis. Therefore, we have established a BrdU-Hoechst stain quenching protocol for analyzing nuclei directly isolated from delicate plant cell suspension cultures. After adding BrdU to test Harpagophytum procumbens cell suspension cultures the cell cycle distribution could be adequately resolved using its incorporation for the following 72 h (after which BrdU slowed biomass accumulation). Despite this limitation, the protocol allows resolution of the cell cycle distribution of cultures that cannot be analyzed using commonly applied methods due to the cells' fragility. The presented protocol enabled analysis of cycling heterogeneities in H. procumbens batch cultivations, and thus should facilitate process control of secondary metabolite production from fragile plant in vitro cultures. Biotechnol. Bioeng. 2016;113: 1244-1250. © 2015 Wiley Periodicals, Inc. PMID:26614913

  7. Experimental methods and modeling techniques for description of cell population heterogeneity

    DEFF Research Database (Denmark)

    Lencastre Fernandes, Rita; Nierychlo, M.; Lundin, L.;

    2011-01-01

    is acknowledged but seldom accounted for. In order to include population heterogeneity mechanisms in the development of novel bioprocess control strategies, a reliable mathematical description of such phenomena has to be developed. With this review, we search to summarize the potential of currently...

  8. A Semianalytical Model Using MODIS Data to Estimate Cell Density of Red Tide Algae (Aureococcus anophagefferens)

    OpenAIRE

    Lingling Jiang; Lin Wang; Xinyu Zhang; Yanlong Chen; Deqi Xiong

    2016-01-01

    A multiband and a single-band semianalytical model were developed to predict algae cell density distribution. The models were based on cell density (N) dependent parameterizations of the spectral backscattering coefficients, bb(λ), obtained from in situ measurements. There was a strong relationship between bb(λ) and N, with a minimum regression coefficient of 0.97 at 488 nm and a maximum value of 0.98 at other bands. The cell density calculated by the multiband inversion model was similar to ...

  9. Tumor heterogeneity as a rationale for a multi-epitope approach in an autologous renal cell cancer tumor vaccine

    Directory of Open Access Journals (Sweden)

    Wittke S

    2016-01-01

    Full Text Available Stefan Wittke,1 Susann Baxmann,2 Dirk Fahlenkamp,3 Stephan T Kiessig2 1University of Applied Sciences Bremerhaven, Faculty of Biotechnology Bremerhaven, 2Ruhr-Plasma-Centre GmbH, Bochum, 3Department of Urology, Zeisigwald Bethanien Hospital, Chemnitz, Germany Purpose: An autologous tumor vaccine already used successfully in the immune therapy of renal cell carcinoma was investigated in detail. The evaluation of potential tumor markers should allow for the assessment of potency according to pharmaceutical regulations.Methods: A panel of 36 tumor-associated antigens and cellular marker proteins was characterized in a total of 133 tumor cell lysates by methods such as ELISA, Western blots, and topological proteomics. The induction of tumor-associated antigen-specific antibodies was demonstrated by immunization in mice.Results: Tumor heterogeneity was demonstrated: none of the tumor-associated antigens investigated were detectable in each tumor lysate. In parallel, the coincidental presence of potential danger signals was shown for HSP-60 and HSP-70. The presence of both antigen and danger signal allowed a successful induction of an immune response in a murine model.Conclusion: The verified tumor heterogeneity indicates the need for a multi-epitope approach for the successful immunotherapy in renal cell carcinoma. Keywords: renal cell carcinoma, kidney cancer, tumor-associated antigens, tumor marker, ELISA, Western Blot, immunotherapy, therapeutic vaccine, potency testing, topological proteomics

  10. Variable viscosity and density biofilm simulations using an immersed boundary method, part II: Experimental validation and the heterogeneous rheology-IBM

    Science.gov (United States)

    Stotsky, Jay A.; Hammond, Jason F.; Pavlovsky, Leonid; Stewart, Elizabeth J.; Younger, John G.; Solomon, Michael J.; Bortz, David M.

    2016-07-01

    The goal of this work is to develop a numerical simulation that accurately captures the biomechanical response of bacterial biofilms and their associated extracellular matrix (ECM). In this, the second of a two-part effort, the primary focus is on formally presenting the heterogeneous rheology Immersed Boundary Method (hrIBM) and validating our model by comparison to experimental results. With this extension of the Immersed Boundary Method (IBM), we use the techniques originally developed in Part I ([19]) to treat biofilms as viscoelastic fluids possessing variable rheological properties anchored to a set of moving locations (i.e., the bacteria locations). In particular, we incorporate spatially continuous variable viscosity and density fields into our model. Although in [14,15], variable viscosity is used in an IBM context to model discrete viscosity changes across interfaces, to our knowledge this work and Part I are the first to apply the IBM to model a continuously variable viscosity field. We validate our modeling approach from Part I by comparing dynamic moduli and compliance moduli computed from our model to data from mechanical characterization experiments on Staphylococcus epidermidis biofilms. The experimental setup is described in [26] in which biofilms are grown and tested in a parallel plate rheometer. In order to initialize the positions of bacteria in the biofilm, experimentally obtained three dimensional coordinate data was used. One of the major conclusions of this effort is that treating the spring-like connections between bacteria as Maxwell or Zener elements provides good agreement with the mechanical characterization data. We also found that initializing the simulations with different coordinate data sets only led to small changes in the mechanical characterization results. Matlab code used to produce results in this paper will be available at https://github.com/MathBioCU/BiofilmSim.

  11. Carbonic anhydrase IX induction defines a heterogeneous cancer cell response to hypoxia and mediates stem cell-like properties and sensitivity to HDAC inhibition.

    Science.gov (United States)

    Ledaki, Ioanna; McIntyre, Alan; Wigfield, Simon; Buffa, Francesca; McGowan, Simon; Baban, Dilair; Li, Ji-Liang; Harris, Adrian L

    2015-08-14

    Carbonic anhydrase IX (CAIX) is strongly induced by hypoxia and its overexpression is associated with poor therapeutic outcome in cancer. Here, we report that hypoxia promotes tumour heterogeneity through the epigenetic regulation of CAIX. Based on hypoxic CAIX expression we identify and characterize two distinct populations of tumour cells, one that has inducible expression of CAIX and one that does not. The CAIX+ve population is enriched with cells expressing cancer stem cell markers and which have high self-renewal capacity. We show that differential CAIX expression is due to differences in chromatin structure. To further investigate the relationship between chromatin organization and hypoxic induction of CAIX expression we investigated the effect of JQ1 an inhibitor of BET bromodomain proteins and A366 a selective inhibitor of the H3K9 methyltransferase G9a/GLP. We identified that these drugs were able to modulate hypoxic CAIX expression induction. This further highlights the role of epigenetic modification in adaption to hypoxia and also in regulation of heterogeneity of cells within tumours. Interestingly, we identified that the two subpopulations show a differential sensitivity to HDAC inhibitors, NaBu or SAHA, with the CAIX positive showing greater sensitivity to treatment. We propose that drugs modulating chromatin regulation of expression may be used to reduce heterogeneity induced by hypoxia and could in combination have significant clinical consequences. PMID:26305601

  12. Ganglion cell and displaced amacrine cell density distribution in the retina of the howler monkey (Alouatta caraya.

    Directory of Open Access Journals (Sweden)

    José Augusto Pereira Carneiro Muniz

    Full Text Available Unlike all other New World (platyrrine monkeys, both male and female howler monkeys (Alouatta sp. are obligatory trichromats. In all other platyrrines, only females can be trichromats, while males are always dichromats, as determined by multiple behavioral, electrophysiological, and genetic studies. In addition to obligatory trichromacy, Alouatta has an unusual fovea, with substantially higher peak cone density in the foveal pit than every other diurnal anthropoid monkey (both platyrrhines and catarrhines and great ape yet examined, including humans. In addition to documenting the general organization of the retinal ganglion cell layer in Alouatta, the distribution of cones is compared to retinal ganglion cells, to explore possible relationships between their atypical trichromacy and foveal specialization. The number and distribution of retinal ganglion cells and displaced amacrine cells were determined in six flat-mounted retinas from five Alouatta caraya. Ganglion cell density peaked at 0.5 mm between the fovea and optic nerve head, reaching 40,700-45,200 cells/mm2. Displaced amacrine cell density distribution peaked between 0.5-1.75 mm from the fovea, reaching mean values between 2,050-3,100 cells/mm2. The mean number of ganglion cells was 1,133,000±79,000 cells and the mean number of displaced amacrine cells was 537,000±61,800 cells, in retinas of mean area 641±62 mm2. Ganglion cell and displaced amacrine cell density distribution in the Alouatta retina was consistent with that observed among several species of diurnal Anthropoidea, both platyrrhines and catarrhines. The principal alteration in the Alouatta retina appears not to be in the number of any retinal cell class, but rather a marked gradient in cone density within the fovea, which could potentially support high chromatic acuity in a restricted central region.

  13. Autonomous Image Segmentation using Density-Adaptive Dendritic Cell Algorithm

    Directory of Open Access Journals (Sweden)

    Vishwambhar Pathak

    2013-08-01

    Full Text Available Contemporary image processing based applications like medical diagnosis automation and analysis of satellite imagery include autonomous image segmentation as inevitable facility. The research done shows the efficiency of an adaptive evolutionary algorithm based on immune system dynamics for the task of autonomous image segmentation. The recognition dynamics of immune-kernels modeled with infinite Gaussian mixture models exhibit the capability to automatically determine appropriate number of segments in presence of noise. In addition, the model using representative density-kernel-parameters processes the information with much reduced space requirements. Experiments conducted with synthetic images as well as real images recorded assured convergence and optimal autonomous model estimation. The segmentation results tested in terms of PBM-index values have been found comparable to those of the Fuzzy C-Means (FCM for the same number of segments as generated by our algorithm.

  14. Expression of Endoglin (CD-105) and Microvessel Density in Oral Dysplasia and Squamous Cell Carcinoma

    OpenAIRE

    Basnaker, Maharudrappa; SR, Shashikanth; BNVS, Satish

    2014-01-01

    Objective: To assess the expression of Endoglin (CD-105) and Microvessel Density in clinically normal oral mucosa of non-tobacco and tobacco habituated patients & also histopathologically confirmed cases of oral squamous cell carcinoma (OSCC) patients.

  15. Efficient production of propionic acid through high density culture with recycling cells of Propionibacterium acidipropionici.

    Science.gov (United States)

    Liu, Zhen; Ge, Yongsheng; Xu, Jing; Gao, Chao; Ma, Cuiqing; Xu, Ping

    2016-09-01

    The aim of this study was to explore propionic acid production via high density culture of Propionibacterium acidipropionici and recycling of cells. Results showed that final cells of P. acidipropionici from high density culture still had high metabolic activity for reuse. Using our process, 75.9gl(-1) propionic acid was produced, which was 1.84-fold of that in fed-batch fermentation with low cell density (41.2gl(-1)); the corresponding productivity was 100.0% higher than that in fed-batch fermentation with low cell density (0.16gl(-1)h(-1)). This bioprocess may have potential for the industrial production of propionic acid. PMID:27318164

  16. Heterogeneous Nuclear Ribonucleoprotein L is required for the survival and functional integrity of murine hematopoietic stem cells

    Science.gov (United States)

    Gaudreau, Marie-Claude; Grapton, Damien; Helness, Anne; Vadnais, Charles; Fraszczak, Jennifer; Shooshtarizadeh, Peiman; Wilhelm, Brian; Robert, François; Heyd, Florian; Möröy, Tarik

    2016-01-01

    The proliferation and survival of hematopoietic stem cells (HSCs) has to be strictly coordinated to ensure the timely production of all blood cells. Here we report that the splice factor and RNA binding protein hnRNP L (heterogeneous nuclear ribonucleoprotein L) is required for hematopoiesis, since its genetic ablation in mice reduces almost all blood cell lineages and causes premature death of the animals. In agreement with this, we observed that hnRNP L deficient HSCs lack both the ability to self-renew and foster hematopoietic differentiation in transplanted hosts. They also display mitochondrial dysfunction, elevated levels of γH2AX, are Annexin V positive and incorporate propidium iodide indicating that they undergo cell death. Lin-c-Kit+ fetal liver cells from hnRNP L deficient mice show high p53 protein levels and up-regulation of p53 target genes. In addition, cells lacking hnRNP L up-regulated the expression of the death receptors TrailR2 and CD95/Fas and show Caspase-3, Caspase-8 and Parp cleavage. Treatment with the pan-caspase inhibitor Z-VAD-fmk, but not the deletion of p53, restored cell survival in hnRNP L deficient cells. Our data suggest that hnRNP L is critical for the survival and functional integrity of HSCs by restricting the activation of caspase-dependent death receptor pathways. PMID:27271479

  17. Green heterogeneous small-cell networks: Toward reducing the CO2 emissions of mobile communications industry using uplink power adaptation

    KAUST Repository

    Shakir, Muhammad Zeeshan

    2013-06-01

    Heterogeneous small cell networks, or Het- SNets, are considered as a standard part of future mobile networks in which multiple lowpower low-cost user deployed base stations complement the existing macrocell infrastructure. This article proposes an energy-efficient deployment of the cells where the small cell base stations are arranged around the edge of the reference macrocell, and the deployment is referred to as cell-on-edge (COE) deployment. The proposed deployment ensures an increase in the network spectral and energy efficiency by facilitating cell edge mobile users with small cells. Moreover, COE deployment guarantees reduction of the carbon footprint of mobile operations by employing adaptive uplink power control. In order to calibrate the reduction in CO2 emissions, this article quantifies the ecological and associated economical impacts of energy savings in the proposed deployment. Simulation results quantify the improvements in CO2 emissions and spectral and energy gains of the proposed COE deployment compared to macro-only networks and typical small cell deployment strategies where small cells are randomly deployed within a given macrocell. © 2013 IEEE.

  18. Inhibition of Cellular Growth of Melanoma Cells Line by Heterogeneous Beta Chronic Irradiation at Very Low-Dose-Rate

    International Nuclear Information System (INIS)

    Radioisotopes that decay via beta emission are widely used in science and medicine. The main advantage of beta-emitters is the relatively long path length in biological tissue (in the mm range). The objective of this work was to determine the inhibition of cellular growth of melanoma cells (melanoma cells are one of the most radioresistant tumor cells) by beta irradiation at very low dose rate using a simple and economic device. This irradiation system represents a situation similar to radiodiagnostic, radioimmunotherapy and brachytherapy because there is a continuous emission of exponentially decreasing low-dose-rate irradiation with heterogeneous dose deposition. It permitted us to study different dose rates changing only the activity of beta emitter. We compare it with the high dose rate gamma irradiation. (authors)

  19. Molecular and stimulus-response profiles illustrate heterogeneity between peripheral and cord blood-derived human mast cells

    DEFF Research Database (Denmark)

    Jensen, Bettina M; Frandsen, Pernille M; Raaby, Ellen M; Schiøtz, Peter Oluf; Skov, Per S; Poulsen, Lars K

    2014-01-01

    functionality. Mast cells were obtained from three culture protocols using two types of PBdMCs (CD34(+) PBdMC or CD133(+) PBdMC) and one type of CBdMC (CD133(+) CBdMC). We analyzed resting cells for specific mast cell markers at protein and mRNA levels, thereby creating a molecular profile. To characterize the......(+) and CD133(+) PBdMC. The SR profile for histamine release illustrated a functional heterogeneity between PBdMC and CBdMC. PBdMC released >10% histamine upon stimulation with anti-IgE, C3a, Substance P, and Compound 48/80, whereas CBdMC only reacted to C3a. Cytokine secretion was only detected after...

  20. Substrate compliance versus ligand density in cell on gel responses

    Czech Academy of Sciences Publication Activity Database

    Engler, A.; Bačáková, Lucie; Newman, C.; Hategan, A.; Griffin, M.; Discher, D.

    2004-01-01

    Roč. 86, č. 1 (2004), s. 617-628. ISSN 0006-3495 Grant ostatní: GA-(US) National Science Foundation; GA-(US) National Institutes of Health; GA-(US) Muscular Dystrophy Association Institutional research plan: CEZ:AV0Z5011922 Keywords : material stiffness * cell spreading * focal adhesions Subject RIV: BO - Biophysics Impact factor: 4.585, year: 2004

  1. Contamination of a high-cell-density continuous bioreactor

    OpenAIRE

    Domingues, Lucília; Lima, Nelson; Teixeira, J. A.

    2000-01-01

    Continuous fermentations were carried out with a recombinant flocculent Saccharomyces cerevisiae strain in an airlift bioreactor. Once operating under steady state at a dilution rate of 0.45 h−1, the bioreactor was contaminated with Escherichia coli cells. The faster growing E. coli strain was washed out of the bioreactor and the recombinant, slower growing flocculating S. cerevisiae strain remained as the only species detected in the bioreactor. Flocculation, besides ...

  2. Cell density related gene expression: SV40 large T antigen levels in immortalized astrocyte lines

    Directory of Open Access Journals (Sweden)

    Jacobberger James W

    2002-04-01

    Full Text Available Abstract Background Gene expression is affected by population density. Cell density is a potent negative regulator of cell cycle time during exponential growth. Here, we asked whether SV40 large T antigen (Tag levels, driven by two different promoters, changed in a predictable and regular manner during exponential growth in clonal astrocyte cell lines, immortalized and dependent on Tag. Results Expression and cell cycle phase fractions were measured and correlated using flow cytometry. T antigen levels did not change or increased during exponential growth as a function of the G1 fraction and increasing cell density when Tag was transcribed from the Moloney Murine Leukemia virus (MoMuLV long terminal repeat (LTR. When an Rb-binding mutant T antigen transcribed from the LTR was tested, levels decreased. When transcribed from the herpes thymidine kinase promoter, Tag levels decreased. The directions of change and the rates of change in Tag expression were unrelated to the average T antigen levels (i.e., the expression potential. Conclusions These data show that Tag expression potential in these lines varies depending on the vector and clonal variation, but that the observed level depends on cell density and cell cycle transit time. The hypothetical terms, expression at zero cell density and expression at minimum G1 phase fraction, were introduced to simplify measures of expression potential.

  3. Cell Selection Game for Densely-Deployed Sensor and Mobile Devices In 5G Networks Integrating Heterogeneous Cells and the Internet of Things

    Science.gov (United States)

    Wang, Lusheng; Wang, Yamei; Ding, Zhizhong; Wang, Xiumin

    2015-01-01

    With the rapid development of wireless networking technologies, the Internet of Things and heterogeneous cellular networks (HCNs) tend to be integrated to form a promising wireless network paradigm for 5G. Hyper-dense sensor and mobile devices will be deployed under the coverage of heterogeneous cells, so that each of them could freely select any available cell covering it and compete for resource with others selecting the same cell, forming a cell selection (CS) game between these devices. Since different types of cells usually share the same portion of the spectrum, devices selecting overlapped cells can experience severe inter-cell interference (ICI). In this article, we study the CS game among a large amount of densely-deployed sensor and mobile devices for their uplink transmissions in a two-tier HCN. ICI is embedded with the traditional congestion game (TCG), forming a congestion game with ICI (CGI) and a congestion game with capacity (CGC). For the three games above, we theoretically find the circular boundaries between the devices selecting the macrocell and those selecting the picocells, indicated by the pure strategy Nash equilibria (PSNE). Meanwhile, through a number of simulations with different picocell radii and different path loss exponents, the collapse of the PSNE impacted by severe ICI (i.e., a large number of picocell devices change their CS preferences to the macrocell) is profoundly revealed, and the collapse points are identified. PMID:26393617

  4. Cell Selection Game for Densely-Deployed Sensor and Mobile Devices In 5G Networks Integrating Heterogeneous Cells and the Internet of Things.

    Science.gov (United States)

    Wang, Lusheng; Wang, Yamei; Ding, Zhizhong; Wang, Xiumin

    2015-01-01

    With the rapid development of wireless networking technologies, the Internet of Things and heterogeneous cellular networks (HCNs) tend to be integrated to form a promising wireless network paradigm for 5G. Hyper-dense sensor and mobile devices will be deployed under the coverage of heterogeneous cells, so that each of them could freely select any available cell covering it and compete for resource with others selecting the same cell, forming a cell selection (CS) game between these devices. Since different types of cells usually share the same portion of the spectrum, devices selecting overlapped cells can experience severe inter-cell interference (ICI). In this article, we study the CS game among a large amount of densely-deployed sensor and mobile devices for their uplink transmissions in a two-tier HCN. ICI is embedded with the traditional congestion game (TCG), forming a congestion game with ICI (CGI) and a congestion game with capacity (CGC). For the three games above, we theoretically find the circular boundaries between the devices selecting the macrocell and those selecting the picocells, indicated by the pure strategy Nash equilibria (PSNE). Meanwhile, through a number of simulations with different picocell radii and different path loss exponents, the collapse of the PSNE impacted by severe ICI (i.e., a large number of picocell devices change their CS preferences to the macrocell) is profoundly revealed, and the collapse points are identified. PMID:26393617

  5. Cell Selection Game for Densely-Deployed Sensor and Mobile Devices In 5G Networks Integrating Heterogeneous Cells and the Internet of Things

    Directory of Open Access Journals (Sweden)

    Lusheng Wang

    2015-09-01

    Full Text Available With the rapid development of wireless networking technologies, the Internet of Things and heterogeneous cellular networks (HCNs tend to be integrated to form a promising wireless network paradigm for 5G. Hyper-dense sensor and mobile devices will be deployed under the coverage of heterogeneous cells, so that each of them could freely select any available cell covering it and compete for resource with others selecting the same cell, forming a cell selection (CS game between these devices. Since different types of cells usually share the same portion of the spectrum, devices selecting overlapped cells can experience severe inter-cell interference (ICI. In this article, we study the CS game among a large amount of densely-deployed sensor and mobile devices for their uplink transmissions in a two-tier HCN. ICI is embedded with the traditional congestion game (TCG, forming a congestion game with ICI (CGI and a congestion game with capacity (CGC. For the three games above, we theoretically find the circular boundaries between the devices selecting the macrocell and those selecting the picocells, indicated by the pure strategy Nash equilibria (PSNE. Meanwhile, through a number of simulations with different picocell radii and different path loss exponents, the collapse of the PSNE impacted by severe ICI (i.e., a large number of picocell devices change their CS preferences to the macrocell is profoundly revealed, and the collapse points are identified.

  6. Rapid effect of heat shock on two heterogeneous nuclear ribonucleoprotein-associated antigens in HeLa cells

    OpenAIRE

    1989-01-01

    During severe heat shock, which known to interrupt both splicing of RNA transcripts and nucleocytoplasmic transport, it is to be expected that the substructure of heterogeneous nuclear ribonucleoproteins (hnRNP) is altered in some way. Recently, we have shown that such a stress actually induces rapid alterations at the level of individual proteins (Lutz, Y., M. Jacob, and J.-P. Fuchs. 1988 Exp. Cell Res. 175:109-124). Here we report further investigations on two related 72.5-74-kD hnRNP prote...

  7. Transcriptional profiling of dividing tumor cells detects intratumor heterogeneity linked to cell proliferation in a brain tumor model

    Czech Academy of Sciences Publication Activity Database

    Endaya, B.; Lam, P.Y.P.; Meedeniya, A.C.B.; Neužil, Jiří

    2016-01-01

    Roč. 10, č. 1 (2016), s. 126-137. ISSN 1574-7891 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:86652036 Keywords : Intratumor heterogeneity * Click chemistry * Proliferation * Gene profiling Subject RIV: FD - Oncology ; Hematology Impact factor: 5.331, year: 2014

  8. Heterogeneity of thymic epithelial cells in promoting T-lymphocyte differentiation in vivo.

    OpenAIRE

    Gutierrez, J C; Palacios, R

    1991-01-01

    To study in vivo the contribution of different thymic epithelial cells to T-lymphocyte differentiation, we have established several nontransformed thymic epithelial cell lines and developed an in vivo assay, not involving exposure to drugs or radiation, that permitted us to study the capacity of these epithelial lines to support T-cell differentiation. We found that cell lines EA2 and ET, which express markers of cortical epithelial cells, produce interleukin 7 mRNA and after being injected i...

  9. Density measurement of samples under high pressure using synchrotron microtomography and diamond anvil cell techniques

    International Nuclear Information System (INIS)

    An algorithm is developed to extract accurate mass density information from tomography data of a sample embedded in a diamond anvil cell in a high-pressure environment. Accurate mass density information is critical in high-pressure studies of materials. It is, however, very difficult to measure the mass densities of amorphous materials under high pressure with a diamond anvil cell (DAC). Employing tomography to measure mass density of amorphous samples under high pressure in a DAC has recently been reported. In reality, the tomography data of a sample in a DAC suffers from not only noise but also from the missing angle problem owing to the geometry of the DAC. An algorithm that can suppress noise and overcome the missing angle problem has been developed to obtain accurate mass density information from such ill-posed data. The validity of the proposed methods was supported with simulations

  10. Thermo-mechanical behavior of high level horizontal disposal cell during the period of exploitation under the heterogeneous load

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. The present work aims to study the evolution of the thermo-mechanical behavior of a horizontal disposal cell under the heterogeneous load during the period of exploitation of 100 years. This heterogeneity of load is due to the generated heat of seven high level waste packages of 1.6 m long which are intercalary disposed in 30 m of the horizontal cell following the concept in 2005 of ANDRA. The analyses have been conducted with different scenarios. The first one consists of modeling the whole length of the disposal cell but the lining is not taken into account for the sake of simplicity. In this case, the generated heat is heterogeneously distributed along the surface of cell. Precisely, at each position of 1.6 m of these seven disposal packages, the uniform heat flux calculated from the thermal power of a high level (HA-C5) waste package is imposed. The model 3D vertically extended from the natural surface to 1000 m of profound allows to account the Callovo-Oxfordian clay as well as its surrounding layers. Moreover, the length of model following the axial direction of the disposal cell is taken equal to 53 m which corresponds to the half distance between axes of the access drift. Following the other horizontal direction which is perpendicular to the axis of cell, a length of 6 m is considered by assuming the symmetrical condition between two disposal cells. This case of study using the coarse mesh is then completed by another model with only 2.35 m of length in the axial direction of disposal cell which allows to increase the precision of the results by using a finer mesh. This length represents a half of a waste package and a half of intercalary distance between two packages. Similarly to the first case, the uniform thermal flux of the half package is imposed on 0.8 m of the wall of the horizontal cell. The thermo-mechanical behavior of materials was used in all simulations by using the Flac3D (ITASCA) code based

  11. Laser microdissection and genetic manipulation technologies to probe lignin heterogeneity and configuration in plant cell walls.

    Science.gov (United States)

    Corea, Oliver R A; Ki, Chanyoung; Cardenas, Claudia L; Davin, Laurence B; Lewis, Norman G

    2012-01-01

    Single and multiple T-DNA knockouts of genes encoding arogenate dehydratases (ADTs) in Arabidopsis were obtained in homozygous form. These were analyzed for potential differences in lignin contents and compositions, as well as for distinct phenotypes over growth and development. Of these different lines, distinct reductions in lignin contents were obtained, with those having different G:S ratios depending upon the combination of ADT genes being knocked out. Results from pyrolysis GC/MS analyses indicated that differential carbon flux occurred into the vascular bundles (vb) and interfascicular fibers (if). These results provide additional new insight into factors controlling lignin heterogeneity and configuration. PMID:22843403

  12. Submicron-Scale Heterogeneities in Nickel Sorption of Various Cell-Mineral Aggregates Formed by Fe(II)-Oxidizing Bacteria.

    Science.gov (United States)

    Schmid, Gregor; Zeitvogel, Fabian; Hao, Likai; Ingino, Pablo; Adaktylou, Irini; Eickhoff, Merle; Obst, Martin

    2016-01-01

    Fe(II)-oxidizing bacteria form biogenic cell-mineral aggregates (CMAs) composed of microbial cells, extracellular organic compounds, and ferric iron minerals. CMAs are capable of immobilizing large quantities of heavy metals, such as nickel, via sorption processes. CMAs play an important role for the fate of heavy metals in the environment, particularly in systems characterized by elevated concentrations of dissolved metals, such as mine drainage or contaminated sediments. We applied scanning transmission (soft) X-ray microscopy (STXM) spectrotomography for detailed 3D chemical mapping of nickel sorbed to CMAs on the submicron scale. We analyzed different CMAs produced by phototrophic or nitrate-reducing microbial Fe(II) oxidation and, in addition, a twisted stalk structure obtained from an environmental biofilm. Nickel showed a heterogeneous distribution and was found to be preferentially sorbed to biogenically precipitated iron minerals such as Fe(III)-(oxyhydr)oxides and, to a minor extent, associated with organic compounds. Some distinct nickel accumulations were identified on the surfaces of CMAs. Additional information obtained from scatter plots and angular distance maps, showing variations in the nickel-iron and nickel-organic carbon ratios, also revealed a general correlation between nickel and iron. Although a high correlation between nickel and iron was observed in 2D maps, 3D maps revealed this to be partly due to projection artifacts. In summary, by combining different approaches for data analysis, we unambiguously showed the heterogeneous sorption behavior of nickel to CMAs. PMID:26588096

  13. Insulin-like growth factor-II receptors in cultured rat hepatocytes: regulation by cell density

    International Nuclear Information System (INIS)

    Insulin-like growth factor-II (IGF-II) receptors in primary cultures of adult rat hepatocytes were characterized and their regulation by cell density examined. In hepatocytes cultured at 5 X 10(5) cells per 3.8 cm2 plate [125I]IGF-II bound to specific, high affinity receptors (Ka = 4.4 +/- 0.5 X 10(9) l/mol). Less than 1% cross-reactivity by IGF-I and no cross-reactivity by insulin were observed. IGF-II binding increased when cells were permeabilized with 0.01% digitonin, suggesting the presence of an intracellular receptor pool. Determined by Scatchard analysis and by polyacrylamide gel electrophoresis after affinity labeling, the higher binding was due solely to an increase in binding sites present on 220 kDa type II IGF receptors. In hepatocytes cultured at low densities, the number of cell surface receptors increased markedly, from 10-20,000 receptors per cell at a culture density of 6 X 10(5) cells/well to 70-80,000 receptors per cell at 0.38 X 10(5) cells/well. The increase was not due simply to the exposure of receptors from the intracellular pool, as a density-related increase in receptors was also seen in cells permeabilized with digitonin. There was no evidence that IGF binding proteins, either secreted by hepatocytes or present in fetal calf serum, had any effect on the measurement of receptor concentration or affinity. We conclude that rat hepatocytes in primary culture contain specific IGF-II receptors and that both cell surface and intracellular receptors are regulated by cell density

  14. Age-related decrease in rod bipolar cell density of the human retina: an immunohistochemical study

    Indian Academy of Sciences (India)

    P Aggarwal; T C Nag; S Wadhwa

    2007-03-01

    During normal ageing, the rods (and other neurones) undergo a significant decrease in density in the human retina from the fourth decade of life onward. Since the rods synapse with the rod bipolar cells in the outer plexiform layer, a decline in rod density (mainly due to death) may ultimately cause an associated decline of the neurones which, like the rod bipolar cells, are connected to them. The rod bipolar cells are selectively stained with antibodies to protein kinase C-. This study examined if rod bipolar cell density changes with ageing of the retina, utilizing donor human eyes (age: 6–91 years). The retinas were fixed and their temporal parts from the macula to the mid-periphery sectioned and processed for protein kinase C- immunohistochemistry. The density of the immunopositive rod bipolar cells was estimated in the mid-peripheral retina (eccentricity: 3–5 mm) along the horizontal temporal axis. The results show that while there is little change in the density of the rod bipolar cells from 6 to 35 years (2.2%), the decline during the period from 35 to 62 years is about 21% and between seventh and tenth decades, it is approximately 27%.

  15. Superoxide-mediated modification of low density lipoprotein by arterial smooth muscle cells.

    OpenAIRE

    Heinecke, J W; Baker, L; Rosen, H; Chait, A.

    1986-01-01

    Extracellular superoxide was detected in cultures of monkey and human arterial smooth muscle cells as indicated by superoxide dismutase inhibitable reduction of cytochrome c. Superoxide production by these cells in the presence of Fe or Cu resulted in modification of low density lipoprotein (LDL). The degree of LDL modification was directly proportional to the rate of superoxide production by cells. Superoxide dismutase (100 micrograms/ml), and the general free radical scavengers butylated hy...

  16. Comparison of the Blood and Lymphatic Microvessel Density of Pleomorphic Adenoma and Basal Cell Adenoma

    OpenAIRE

    Andresa Borges Soares; Albina Altemani; Thais Ribeiro de Oliveira; Felipe de Oliveira Fonseca Rodrigues; Alfredo Ribeiro-Silva; Danilo Figueiredo Soave; Fabricio Passador-Santos; Suellen Trentin Brum; Marcelo Henrique Napimoga; Vera Cavalcanti de Araújo

    2015-01-01

    BACKGROUND Pleomorphic adenoma (PA) is the most common tumor of the salivary gland, while basal cell adenoma (BCA) is an uncommon neoplasm. Blood and lymphatic vessels are crucial for tumor metabolism. The aim of this study was to compare the blood and lymphatic vascular density and vascular and endothelial growth factor (VEGF) expression in PA and BCA tumors. In addition, cell proliferation was evaluated in these tumors. METHODS Blood and lymphatic vessel content, VEGF expression, and cell p...

  17. Insulated gold micro singularities for high density cell trapping based on dielectrophoresis

    OpenAIRE

    Dalmay, Claire; Francais, Olivier; Subra, Frédéric; Le Pioufle, Bruno

    2011-01-01

    Dielectrophoresis (DEP) is broadly used in microfluidic systems for the cell therapies or medical diagnostics [1] because of its capability to handle and sort biological cells [2,3]. In this paper, a new method to trap cells on-chip with high density arraying capabilities is proposed. The principle is based on the use of metallic singularities arrayed within the flowing channel of the biochip. These singularities, even at a floating potential, induce a non uniform electrical field within the ...

  18. Subtype differentiation of small renal cell carcinomas on three-phase MDCT: usefulness of the measurement of degree and heterogeneity of enhancement

    International Nuclear Information System (INIS)

    Background. Subtype differentiation of small renal cell carcinomas (RCCs) can provide more information to surgeons and patients and get more useful information about imaging features of small renal tumors. Purpose. To evaluate the usefulness of the measurement of degree and heterogeneity of enhancement in subtype differentiation of small renal cell carcinomas (RCCs) by three-phase multidetector-row CT (MDCT). Material and Methods. We reviewed 149 pathologically confirmed small (<4cm) RCCs in 143 patients: 114 (clear cell), 17 (chromophobe), and 18 papillary (8 papillary type 1 and 10 papillary type 2). Scans in pre-contrast, corticomedullary, and nephrographic phases were obtained. We assessed the mean and standard deviation of the Hounsfield units (HU) in a region of interest (ROI) for the degree of enhancement and the heterogeneity of enhancement, respectively. We compared the attenuation values, and the degree and heterogeneity of enhancement among the subtypes. Results. The clear cell type showed the highest enhancement and heterogeneity of enhancement followed by chromophobe and papillary types. There was a significant difference in enhancement between the clear cell and papillary types in the corticomedullary phase (P < 0.01), and between clear and non-clear cell types in the nephrographic phase (P < 0.05). Heterogeneity of enhancement showed a significant difference between clear cell and non-clear cell types in the corticomedullary phase (P < 0.05). Conclusion. The measurement of degree and heterogeneity of enhancement on contrast-enhanced MDCT may be a simple and useful method to differentiate between the different types of small RCCs

  19. Cell cycle responses of heterogeneous human colon adenocarcinoma subpopulations to X-irradiation

    International Nuclear Information System (INIS)

    The cell cycle responses of two exponentially growing subpopulations of cells (clones A and D), originally obtained from a human colon adenocarcinoma to X-irradiation, were studied using centrifugal elutriation. Cell suspensions were separated by changing counter-current flow rate while keeping the rotor speed constant and the composition of eluted fractions was determined using flow cytometry. The X-ray sensitivity of unseparated clone D cells was somewhat greater than that of clone A cells. This difference appeared to be due to a greater value of the α parameter (one-hit cell killing), using the linear-quadratic equation in which the relative survival S/Ssub(o) = exp -(αD + βD2) with dose (D) in Gy. This finding was confirmed in the cell cycle studies where the α parameter was always greater for the clone D cells than for the clone A cells. The β parameter was essentially the same for both cell lines through the cell cycle. (author)

  20. Heterogeneity in the differentiation and function of CD8⁺ T cells.

    Science.gov (United States)

    Mittrücker, Hans-Willi; Visekruna, Alexander; Huber, Magdalena

    2014-12-01

    It is well established that CD8(+) T cells constitute an important branch of adaptive immunity contributing to clearance of intracellular pathogens and providing long-term protection. These functions are mostly fulfilled by the best characterized subpopulation of CD8(+) T cells, the cytotoxic T lymphocytes (also called Tc1 cells), owing to their ability to kill infected cells and to secrete cytokines such as interferon-γ and tumor necrosis factor-α. However, there is growing evidence for alternative CD8(+) T cell fates influencing CD4(+) T-cell-mediated responses in the context of allergy, autoimmunity and infections. Thus, like subpopulations of CD4(+) T cells, also CD8(+) T cells under particular conditions acquire the expression of interleukin (IL)-4, IL-5, IL-9, IL-13, IL-17 or suppressive activity and thereby influence immune responses. The process of CD8(+) T-cell differentiation is dictated by antigen strength, co-stimulatory molecules and cytokines. These environmental cues induce transcription factors further specifying CD8(+) T-cell decision into Tc1, Tc2, Tc9, Tc17 or CD8(+) T regulatory fate. Here, we discuss our current understanding about functional diversity of effector CD8(+) T cells and contribution of transcription factors to this process. PMID:24879097

  1. A novel dual-color reporter for identifying insulin-producing beta-cells and classifying heterogeneity of insulinoma cell lines.

    Directory of Open Access Journals (Sweden)

    Nan Sook Lee

    Full Text Available Many research studies use immortalized cell lines as surrogates for primary beta- cells. We describe the production and use of a novel "indirect" dual-fluorescent reporter system that leads to mutually exclusive expression of EGFP in insulin-producing (INS(+ beta-cells or mCherry in non-beta-cells. Our system uses the human insulin promoter to initiate a Cre-mediated shift in reporter color within a single transgene construct and is useful for FACS selection of cells from single cultures for further analysis. Application of our reporter to presumably clonal HIT-T15 insulinoma cells, as well as other presumably clonal lines, indicates that these cultures are in fact heterogeneous with respect to INS(+ phenotype. Our strategy could be easily applied to other cell- or tissue-specific promoters. We anticipate its utility for FACS purification of INS(+ and glucose-responsive beta-like-cells from primary human islet cell isolates or in vitro differentiated pluripotent stem cells.

  2. Heterogeneous vesicles in mucous epithelial cells of posterior esophagus of Chinese giant salamander (Andrias davidianus).

    Science.gov (United States)

    Zhang, H; Guo, X; Zhong, S; Ge, T; Peng, S; Yu, P; Zhou, Z

    2015-01-01

    The Chinese giant salamander belongs to an old lineage of salamanders and endangered species. Many studies of breeding and disease regarding this amphibian had been implemented. However, the studies on the ultrastructure of this amphibian are rare. In this work, we provide a histological and ultrastructural investigation on posterior esophagus of Chinese giant salamander. The sections of amphibian esophagus were stained by hematoxylin & eosin (H&E). Moreover, the esophageal epithelium was observed by transmission electron microscopy (TEM). The results showed that esophageal epithelium was a single layer epithelium, which consisted of mucous cells and columnar cells. The esophageal glands were present in submucosa. The columnar cells were ciliated. According to the diverging ultrastructure of mucous vesicles, three types of mucous cells could be identified in the esophageal mucosa: i) electron-lucent vesicles mucous cell (ELV-MC); ii) electron-dense vesicles mucous cell (EDV-MC); and iii) mixed vesicles mucous cell (MV-MC). PMID:26428885

  3. Heterogeneous vesicles in mucous epithelial cells of posterior esophagus of Chinese giant salamander (Andrias davidianus

    Directory of Open Access Journals (Sweden)

    H. Zhang

    2015-08-01

    Full Text Available The Chinese giant salamander belongs to an old lineage of salamanders and endangered species. Many studies of breeding and disease regarding this amphibian had been implemented. However, the studies on the ultrastructure of this amphibian are rare. In this work, we provide a histological and ultrastructural investigation on posterior esophagus of Chinese giant salamander. The sections of amphibian esophagus were stained by hematoxylin & eosin (H&E. Moreover, the esophageal epithelium was observed by transmission electron microscopy (TEM. The results showed that esophageal epithelium was a single layer epithelium, which consisted of mucous cells and columnar cells. The esophageal glands were present in submucosa. The columnar cells were ciliated. According to the diverging ultrastructure of mucous vesicles, three types of mucous cells could be identified in the esophageal mucosa: i electron-lucent vesicles mucous cell (ELV-MC; ii electron-dense vesicles mucous cell (EDV-MC; and iii mixed vesicles mucous cell (MV-MC.

  4. How do heterogeneities in single cell rigidity influence the mechanical behavior at the tissue level?

    Science.gov (United States)

    Bi, Dapeng; Wetzel, Franziska; Fritsch, Anatol; Marchetti, M. Cristina; Manning, M. Lisa; Kaes, Josef

    It has been long recognized that solid tumor tissues are mechanically more rigid than surrounding healthy tissues. However recent experiments have shown that in primary tumor samples from patients with mammary and cervix carcinomas, cells exhibit a broad distribution of rigidities, with a higher fraction of softer and more contractile cells compared to normal tissues. This gives rise to a paradox: does softness emerge from adaptation to mechanical and chemical cues in the external microenvironment, or are soft cells already present inside a primary solid tumor? Motivated by these observations, we study a model of dense tissues that incorporates the experimental data for cell stiffness variations to reveal that, surprisingly, tumors with a significant fraction of very soft cells can still remain rigid. Moreover, in tissues with the observed distributions of cell stiffnesses, softer cells spontaneously self-organize into lines or streams, possibly facilitating cancer metastasis.

  5. Development of dielectric spectroscopic monitoring methods for the prediction of viable cell density and volume in mammalian cell culture

    OpenAIRE

    O'Regan, Timothy

    2012-01-01

    The objective of this study is to examine the potential of off-line biomass monitoring methods for the real-time prediction of viable cell density and viable cell volume in Chinese hamster ovary cell cultures. This work focuses on the use of Biomass Monitor for the monitoring of biomass. Two dual frequency settings and 2 temperatures were examined. The effects of interferences when the Biomass Monitor probe is present in a bioreactor are also investigated. The feasibility of constructing a...

  6. Charge heterogeneity of proteins synthesized in cell - free protein synthesis and E. coli minicells

    International Nuclear Information System (INIS)

    Radiolabeled DNA directed protein synthesis in a Zubay type in vitro system as well as in E. coli minicells exhibits an unexpected ambiguity of the gene products. Highly expressed proteins that look homogenous upon SDS gel electrophoresis are separated into a series of spots when analysed according to the method of O'Farrell. Inactivation of one particular gene by a deletion or an insertion event leads to the loss of only a single series of spots. They are encoded by one single gene and are only distinguishable by charge. This charge heterogeneity can not be explained by secondary modification during protein extraction, because only newly synthesized proteins are affected. These proteins can be easily distinguished from hot proteins that form homogenously stained spots. The highest rate of misreading was supposed to appear during translation of the asparagine specific codon AAU. Radiolabeled microsequence analysis enabled us to test this hypothesis more directly

  7. Models of Growth Heterogeneous Cancer Cells with Chains Markoviens and Estimation of Their Fractal Dimension

    Directory of Open Access Journals (Sweden)

    Labib Sadek Terrissa

    2011-09-01

    Full Text Available Although little work in biometrics uses fractal geometry, we will discuss here biometrics cancer tissue examined under a microscope or simulated. The main purpose of our work is the simulation of the heterogeneous growth of cancerous tumors and the analysis of the appearance of their textures. The problem is to quantify the irregularity of their edges, which help enormously oncologists to give diagnoses to evaluate the treatment issued to their patients. We propose new algorithms, which generates growth models with the ability to produce a border irregularity similar to that of cancerous tumors and value their fractal dimension. The established models have two types of parameters: Algorithms describing the structure, and Scalar to quantify aspects modeled

  8. Heterogeneity in c-jun gene expression in normal and malignant cells exposed to either ionizing radiation or hydrogen peroxide

    International Nuclear Information System (INIS)

    We investigated the role of reactive oxygen intermediates and protein kinase C (PKC) in induction of c-jun gene expression in human ML-2 leukemic cells and normal DET-551 fibroblasts by comparing the effects of either ionizing radiation or H2O2 exposure in the presence or absence of appropriate inhibitors. In these cell types, the radiation and H2O2-mediated increase in c-jun mRNA levels could be prevented by pretreatment of the cells with N-acetylcysteine, an antioxidant, or H7, an inhibitor of PKC and cAMP-dependent protein kinase (PKA), but not by HA1004, an inhibitor of PKA. These results suggest a role for PKC and reactive oxygen intermediates in the induction of c-jun gene expression in both normal and tumor cells. We also investigated potential differences in radiation- or H2O2-induced c-jun gene expression in normal and tumor cells by examining steady-state c-jun mRNA levels in a number of human fibroblast, leukemia, melanoma, sarcoma, and carcinoma cell types. We observed heterogeneity in the steady-state level of c-jun mRNA in both the untreated normal and tumor cells and in such cells exposed to ionizing radiation or to H2O2. Exposure to radiation or to hydrogen peroxide produced a varied response which ranged from little or no induction to a more than two orders of magnitude increase in the steady-state level of the c-jun mRNA

  9. Cell size, number and density in the retina ganglion cell layer of Pekin duck retina at different embryonic age

    OpenAIRE

    ZUO Shi-Feng; CHEN Yao-Xing; WANG Zi-Xu; Cao, Jing; Dong, Yu-lan

    2008-01-01

    Changes in cell size, number and density of the ganglion cell layer(GCL)of the Pekin duck retina were studied by using the methods of Nissl-staining and Scion Image picture processing at embryonic age day-11,14,17,20,23 and 26. The result indicated that the cells in GCL were small and round uniformly at E11 and E14. The large cells were first found at E17. From E11 to E26, cell size was increased 1.97-fold in the central area (CA) and 3.1-fold in the temple periphery (TP), and there was si...

  10. Cell damage from radiation-induced bystander effects for different cell densities simulated by a mathematical model via cellular automata

    Energy Technology Data Exchange (ETDEWEB)

    Meireles, Sincler P. de; Santos, Adriano M.; Grynberg, Suely Epsztein, E-mail: spm@cdtn.b, E-mail: amsantos@cdtn.b, E-mail: seg@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Nunes, Maria Eugenia S., E-mail: mariaeugenia@iceb.ufop.b [Universidade Federal de Ouro Preto (UFOP), MG (Brazil)

    2011-07-01

    During recent years, there has been a shift from an approach focused entirely on DNA as the main target of ionizing radiation to a vision that considers complex signaling pathways in cells and among cells within tissues. Several newly recognized responses were classified as the so-called non-target responses in which the biological effects are not directly related to the amount of energy deposited in the DNA of cells that were traversed by radiation. In 1992 the bystander effect was described referring to a series of responses such as death, chromosomal instability or other abnormalities that occur in non-irradiated cells that came into contact with irradiated cells or medium from irradiated cells. In this work, we have developed a mathematical model via cellular automata, to quantify cell death induced by the bystander effect. The model is based on experiments with irradiated cells conditioned medium which suggests that irradiated cells secrete molecules in the medium that are capable of damaging other cells. The computational model consists of two-dimensional cellular automata which is able to simulate the transmission of bystander signals via extrinsic route and via Gap junctions. The model has been validated by experimental results in the literature. The time evolution of the effect and the dose-response curves were obtained in good accordance to them. Simulations were conducted for different values of bystander and irradiated cell densities with constant dose. From this work, we have obtained a relationship between cell density and effect. (author)

  11. Cell damage from radiation-induced bystander effects for different cell densities simulated by a mathematical model via cellular automata

    International Nuclear Information System (INIS)

    During recent years, there has been a shift from an approach focused entirely on DNA as the main target of ionizing radiation to a vision that considers complex signaling pathways in cells and among cells within tissues. Several newly recognized responses were classified as the so-called non-target responses in which the biological effects are not directly related to the amount of energy deposited in the DNA of cells that were traversed by radiation. In 1992 the bystander effect was described referring to a series of responses such as death, chromosomal instability or other abnormalities that occur in non-irradiated cells that came into contact with irradiated cells or medium from irradiated cells. In this work, we have developed a mathematical model via cellular automata, to quantify cell death induced by the bystander effect. The model is based on experiments with irradiated cells conditioned medium which suggests that irradiated cells secrete molecules in the medium that are capable of damaging other cells. The computational model consists of two-dimensional cellular automata which is able to simulate the transmission of bystander signals via extrinsic route and via Gap junctions. The model has been validated by experimental results in the literature. The time evolution of the effect and the dose-response curves were obtained in good accordance to them. Simulations were conducted for different values of bystander and irradiated cell densities with constant dose. From this work, we have obtained a relationship between cell density and effect. (author)

  12. Reversible Adaptive Plasticity: A Mechanism for Neuroblastoma Cell Heterogeneity and Chemo-Resistance

    OpenAIRE

    AnthonyDSandler

    2012-01-01

    We describe a novel form of tumor cell plasticity characterized by reversible adaptive plasticity in murine and human neuroblastoma. Two cellular phenotypes were defined by their ability to exhibit adhered, anchorage dependent (AD) or sphere forming, anchorage independent (AI) growth. The tumor cells could transition back and forth between the two phenotypes and the transition was dependent on the culture conditions. Both cell phenotypes exhibited stem-like features such as expression of nest...

  13. LTE Micro-cell Deployment for High-Density Railway Areas

    DEFF Research Database (Denmark)

    Sniady, Aleksander; Kassab, Mohamed; Soler, José;

    2014-01-01

    Long Term Evolution (LTE) is a serious candidate for the future releases of the European Rail Traffic Management System (ERTMS). LTE offers more capacity and supports new communication-based applications and services for railways. Nevertheless, even with this technology, the classical macro......-cell radio deployments reach overload, especially in high-density areas, such as major train stations. In this paper, an LTE micro-cell deployment is investigated in high-density railway areas. Copenhagen Main Station is considered as a realistic deployment study case, with a set of relevant railway...... communication-based applications. The micro-cell deployment is compared with a classical macro-cell deployment in terms of transmission performance. Simulation results show a capacity improvement in the micro-cell deployment and its positive impact on critical (safety) and non-critical applications....

  14. Computational modeling of heterogeneity and function of CD4+ T cells

    Directory of Open Access Journals (Sweden)

    Adria eCarbo

    2014-07-01

    Full Text Available The immune system is composed of many different cell types and hundreds of intersecting molecular pathways and signals. This large biological complexity requires coordination between distinct pro-inflammatory and regulatory cell subsets to respond to infection while maintaining tissue homeostasis. CD4+ T cells play a central role in orchestrating immune responses and in maintaining a balance between pro- and anti- inflammatory responses. This tight balance between regulatory and effector reactions depends on the ability of CD4+ T cells to modulate distinct pathways within large molecular networks, since dysregulated CD4+ T cell responses may result in chronic inflammatory and autoimmune diseases. The CD4+ T cell differentiation process comprises an intricate interplay between cytokines, their receptors, adaptor molecules, signaling cascades and transcription factors that help delineate cell fate and function. Computational modeling can help to describe, simulate, analyze, and predict some of the behaviors in this complicated differentiation network. This review provides a comprehensive overview of existing computational immunology methods as well as novel strategies used to model immune responses with a particular focus on CD4+ T cell differentiation.

  15. Density of states measurements in a p-i-n solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Crandall, R.S.; Wang, Q. [National Renewable Energy Lab., Golden, CO (United States)

    1996-05-01

    The authors describe results of density of states (DOS) profiling in p-i-n solar-cell devices using drive-level capacitance (DLC) techniques. Near the p-i interface the defect density is high, decreasing rapidly into the interior, reaching low values in the central region of the cell, and rising rapidly again at the n-i interface. They show that the states in the central region are neutral dangling-bond defects, whereas those near the interfaces with the doped layers are charged dangling bonds.

  16. WE-E-17A-05: Complementary Prognostic Value of CT and 18F-FDG PET Non-Small Cell Lung Cancer Tumor Heterogeneity Features Quantified Through Texture Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Desseroit, M; Cheze Le Rest, C; Tixier, F [CHU Poitiers Poitiers (France); INSERM LaTIM UMR 1101, Brest (France); Majdoub, M; Visvikis, D; Hatt, M [INSERM LaTIM UMR 1101, Brest (France); Guillevin, R; Perdrisot, R [CHU Poitiers Poitiers (France)

    2014-06-15

    Purpose: Previous studies have shown that CT or 18F-FDG PET intratumor heterogeneity features computed using texture analysis may have prognostic value in Non-Small Cell Lung Cancer (NSCLC), but have been mostly investigated separately. The purpose of this study was to evaluate the potential added value with respect to prognosis regarding the combination of non-enhanced CT and 18F-FDG PET heterogeneity textural features on primary NSCLC tumors. Methods: One hundred patients with non-metastatic NSCLC (stage I–III), treated with surgery and/or (chemo)radiotherapy, that underwent staging 18F-FDG PET/CT images, were retrospectively included. Morphological tumor volumes were semi-automatically delineated on non-enhanced CT using 3D SlicerTM. Metabolically active tumor volumes (MATV) were automatically delineated on PET using the Fuzzy Locally Adaptive Bayesian (FLAB) method. Intratumoral tissue density and FDG uptake heterogeneities were quantified using texture parameters calculated from co-occurrence, difference, and run-length matrices. In addition to these textural features, first order histogram-derived metrics were computed on the whole morphological CT tumor volume, as well as on sub-volumes corresponding to fine, medium or coarse textures determined through various levels of LoG-filtering. Association with survival regarding all extracted features was assessed using Cox regression for both univariate and multivariate analysis. Results: Several PET and CT heterogeneity features were prognostic factors of overall survival in the univariate analysis. CT histogram-derived kurtosis and uniformity, as well as Low Grey-level High Run Emphasis (LGHRE), and PET local entropy were independent prognostic factors. Combined with stage and MATV, they led to a powerful prognostic model (p<0.0001), with median survival of 49 vs. 12.6 months and a hazard ratio of 3.5. Conclusion: Intratumoral heterogeneity quantified through textural features extracted from both CT and FDG PET

  17. WE-E-17A-05: Complementary Prognostic Value of CT and 18F-FDG PET Non-Small Cell Lung Cancer Tumor Heterogeneity Features Quantified Through Texture Analysis

    International Nuclear Information System (INIS)

    Purpose: Previous studies have shown that CT or 18F-FDG PET intratumor heterogeneity features computed using texture analysis may have prognostic value in Non-Small Cell Lung Cancer (NSCLC), but have been mostly investigated separately. The purpose of this study was to evaluate the potential added value with respect to prognosis regarding the combination of non-enhanced CT and 18F-FDG PET heterogeneity textural features on primary NSCLC tumors. Methods: One hundred patients with non-metastatic NSCLC (stage I–III), treated with surgery and/or (chemo)radiotherapy, that underwent staging 18F-FDG PET/CT images, were retrospectively included. Morphological tumor volumes were semi-automatically delineated on non-enhanced CT using 3D SlicerTM. Metabolically active tumor volumes (MATV) were automatically delineated on PET using the Fuzzy Locally Adaptive Bayesian (FLAB) method. Intratumoral tissue density and FDG uptake heterogeneities were quantified using texture parameters calculated from co-occurrence, difference, and run-length matrices. In addition to these textural features, first order histogram-derived metrics were computed on the whole morphological CT tumor volume, as well as on sub-volumes corresponding to fine, medium or coarse textures determined through various levels of LoG-filtering. Association with survival regarding all extracted features was assessed using Cox regression for both univariate and multivariate analysis. Results: Several PET and CT heterogeneity features were prognostic factors of overall survival in the univariate analysis. CT histogram-derived kurtosis and uniformity, as well as Low Grey-level High Run Emphasis (LGHRE), and PET local entropy were independent prognostic factors. Combined with stage and MATV, they led to a powerful prognostic model (p<0.0001), with median survival of 49 vs. 12.6 months and a hazard ratio of 3.5. Conclusion: Intratumoral heterogeneity quantified through textural features extracted from both CT and FDG PET

  18. Functional heterogeneity within the CD44 high human breast cancer stem cell-like compartment reveals a gene signature predictive of distant metastasis

    DEFF Research Database (Denmark)

    Leth-Larsen, Rikke; Terp, Mikkel Green; Christensen, Anne G;

    2012-01-01

    stem cell features such as tumor-initiating capacity in vivo, mammosphere formation and resistance to standard chemotherapy. This complements previous findings using oncogene-transformed normal mammary cells showing that only cell clones with a mesenchymal phenotype exhibit cancer stem cell features...... in cohorts of estrogen receptor-negative human breast cancers. These findings strongly favor functional heterogeneity in the breast cancer cell compartment and hold promise for further refinements of prognostic marker profiling. Our work confirms that, in addition to cancer stem cells with...

  19. Heterogeneous ceramic interfaces in solid oxide fuel cells and dense oxygen permeable membranes

    OpenAIRE

    Faaland, Sonia

    2000-01-01

    Solid oxide fuel cells and oxygen permeable membranes have received considerable attention during the last decade due to the increasing demand for electrical energy and easily transportable fuels combined with the requirement of low emission of CO2. This work concentrates on the stability of ceramic interfaces in general, and more specifically to heterophase solid state interfaces related to solid oxide fuel cells and oxygen permeable membranes. Reaction mechanisms are discussed and requireme...

  20. Multi-Cell High Latitude Density Structure Induced by Ion Drag during Active Periods

    Science.gov (United States)

    Walterscheid, R. L.; Crowley, G.

    2012-12-01

    During active periods two-cell convection patterns can produce four-cell density structure in the high-latitude thermosphere. During these periods density perturbations approaching 50% are possible. The occurrence of density structures that are more complex than the forcing itself suggests that the structure is caused by a profound change in the balance of forces. Using a General Circulation Model of the thermosphere, we compare the balance of forces in the upper and lower thermosphere during active and quiet times. We also examine the thermal structure caused by the dynamical adjustment to ion-drag forcing in relation to the other terms as a balanced state is approached. Simulations reveal that where ion drag is unable to accelerate the atmosphere into rapid motion (during quiet times or at low thermospheric altitudes) the Coriolis force is the dominant inertial term, and for fixed pressure levels centers of cyclonic motion are (per the usual meteorology relations) colder and denser than the surrounding air, while centers of anticyclonic motion are warmer and less dense. At fixed heights, densities are high in the evening anticyclonic gyre, and low in the dawn cyclonic gyre. However, this situation is radically changed during active periods when the atmosphere is spun up to rapid motion and the centrifugal force resulting from curved trajectories is the dominant inertial force. When this occurs, the high latitude anticyclones and cyclones both become centers of relatively cold high density air at fixed height. Cold low-density centers are found on both the dawn and dusk sides with a trough of low density air over the pole connecting them. This intrusion of low density splits the evening high density region that exists under quiet conditions giving the four cell pattern found by Crowley et al. [1989; 1996a, b]. Crowley, G., J. Schoendorf, R. G. Roble, F. A. Marcos (1996a). Cellular structures in the high latitude lower thermosphere, J. Geophys. Res. 101, 211

  1. Spectral and energy efficiency analysis of uplink heterogeneous networks with small-cells on edge

    KAUST Repository

    Shakir, Muhammad Zeeshan

    2014-12-01

    This paper presents a tractable mathematical framework to analyze the spectral and energy efficiency of an operator initiated deployment of the small-cells (e.g., femtocells) where the small-cell base stations are deliberately positioned around the edge of the macrocell. The considered deployment facilitates the cell-edge mobile users in terms of their coverage, spectral, and energy efficiency and is referred to as cell-on-edge (COE) configuration. The reduction in energy consumption is achieved by considering fast power control where the mobile users transmit with adaptive power to compensate the path loss, shadowing and fading. In particular, we develop a moment generating function (MGF) based approach to derive analytical bounds on the area spectral efficiency and exact expressions for the energy efficiency of the mobile users in the considered COE configuration over generalized-K fading channels. Besides the COE configuration, the derived bounds are also shown to be useful in evaluating the performance of random small-cell deployments, e.g., uniformly distributed small-cells. Simulation results are presented to demonstrate the improvements in spectral and energy efficiency of the COE configuration with respect to macro-only networks and other unplanned deployment strategies. © 2014 Elsevier B.V. All rights reserved.

  2. Cell density-dependent nuclear accumulation of ELK3 is involved in suppression of PAI-1 expression.

    Science.gov (United States)

    Tanaka, Shu; Nakao, Kazuyuki; Sekimoto, Toshihiro; Oka, Masahiro; Yoneda, Yoshihiro

    2013-07-01

    Cell-cell contact regulates the proliferation and differentiation of non-transformed cells, e.g., NIH/3T3 cells show growth arrest at high cell density. However, only a few reports described the dynamic behavior of transcription factors involved in this process. In this study, we showed that the mRNA levels of plasminogen activator inhibitor type 1 (PAI-1) decreased drastically at high cell density, and that ELK3, a member of the Ets transcription factor family, repressed PAI-1 expression. We also demonstrated that while ELK3 was distributed evenly throughout the cell at low cell density, it accumulated in the nucleus at high cell density, and that binding of DNA by ELK3 at the A domain facilitated its nuclear accumulation. Furthermore, we found that ETS1, a PAI-1 activator, occupied the ELK3-binding site within the PAI-1 promoter at low cell density, while it was released at high cell density. These results suggest that at high cell density, the switching of binding of transcription factors from ETS1 to ELK3 occurs at a specific binding site of the PAI-1 promoter, leading to the cell-density dependent suppression of PAI-1 expression. PMID:23708702

  3. Variable Viscosity and Density Biofilm Simulations using an Immersed Boundary Method, Part II: Experimental Validation and the Heterogeneous Rheology-IBM

    OpenAIRE

    Stotsky, Jay A.; Hammond, Jason F.; Pavlovsky, Leonid; Stewart, Elizabeth J.; Younger, John G.; Solomon, Michael J.; Bortz, David M.

    2015-01-01

    The goal of this work is to develop a numerical simulation that accurately captures the biomechanical response of bacterial biofilms and their associated extracellular matrix (ECM). In this, the second of a two-part effort, the primary focus is on formally presenting the heterogeneous rheology Immersed Boundary Method (hrIBM) and validating our model against experimental results. With this extension of the Immersed Bounadry Method (IBM), we use the techniques originally developed in Part I, (...

  4. The Role of Surface Receptor Density in Surface-Initiated Polymerizations for Cancer Cell Isolation.

    Science.gov (United States)

    Lilly, Jacob L; Berron, Brad J

    2016-06-01

    Fluid biopsies potentially offer a minimally invasive alternative to traditional tissue biopsies for the continual monitoring of metastatic cancer. Current established technologies for isolating circulating tumor cells (CTCs) suffer from poor purity and yield and require fixatives that preclude the collection of viable cells for longitudinal analyses of biological function. Antigen specific lysis (ASL) is a rapid, high-purity method of cell isolation based on targeted protective coatings on antigen-presenting cells and lysis depletion of unprotected antigen-negative cells. In ASL, photoinitiators are specifically labeled on cell surfaces that enable subsequent surface-initiated polymerization. Critically, the significant determinants of process yield have yet to be investigated for this emerging technology. In this work, we show that the labeling density of photoinitiators is strongly correlated with the yield of intact cells during ASL by flow cytometry analysis. Results suggest ASL is capable of delivering ∼25% of targeted cells after isolation using traditional antibody labeling approaches. Monomer formulations of two molecular weights of PEG-diacrylate (Mn ∼ 575 and 3500) are examined. The gelation response during ASL polymerization is also investigated via protein microarray analogues on planar glass. Finally, a density threshold of photoinitiator labeling required for protection during lysis is determined for both monomer formulations. These results indicate ASL is a promising technology for high yield CTC isolation for rare-cell function assays and fluid biopsies. PMID:27206735

  5. Cloning and characterization of a novel deletion mutant of heterogeneous nuclear ribonucleoprotein M4 from human dendritic cells

    Institute of Scientific and Technical Information of China (English)

    黄欣; 赵忠良; 袁正隆; 张明徽; 朱学军; 陈国友; 曹雪涛

    2000-01-01

    To identify differentially expressed genes from antigen-stimulated human dendritic cells (DC), subtractive cloning was adopted and more than ten novel genes differentially expressed were cloned. One is a deletion mutant of heterogeneous nuclear ribonucleoprotein (hnRNP) M4 in which the residues from 159 to 197 of hnRNP M4 have been absent. The deletion mutant was shown to- be co-expressed with hnRNP M4 in cell lines. The mutant was expressed in antigen-stimulated DC but not in normal DC. Northern blot analysis revealed the presence of a major hnRNP M4 deletion mutant mRNA transcript of 2.4 kilobase with the highest levels in peripheral lymphocytes, lung, liver and spleen. It was also expressed in bone marrow-derived stromal cells (BMSC), BMSC treated with several cytokines but not in BMSC treated with TNF-a. The results revealed a new member of hnRNP family and suggested that hnRNP would participate in antigen process and presentation.

  6. Cloning and characterization of a novel deletion mutant of heterogeneous nuclear ribonucleoprotein M4 from human dendritic cells

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    To identify differentially expressed genes from antigen-stimulated human dendritic cells (DC), subtractive cloning was adopted and more than ten novel genes differentially expressed were cloned. One is a deletion mutant of heterogeneous nuclear ribonucleoprotein (hnRNP) M4 in which the residues from 159 to 197 of hnRNP M4 have been absent. The deletion mutant was shown to be co-expressed with hnRNP M4 in cell lines. The mutant was expressed in antigen-stimulated DC but not in normal DC. Northern blot analysis revealed the presence of a major hnRNP M4 deletion mutant mRNA transcript of 2.4 kilobase with the highest levels in peripheral lymphocytes, lung, liver and spleen. It was also expressed in bone marrow-derived stromal cells (BMSC), BMSC treated with several cytokines but not in BMSC treated with TNF-a. The results revealed a new member of hnRNP family and suggested that hnRNP would participate in antigen process and presentation.

  7. Cloning and characterization of a novel deletion mutant of heterogeneous nuclear ribonucleoprotein M4 from human dendritic cells

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    To identify differentially expressed genes from antigen-stimulated human dendritic cells (DC), subtractive cloning was adopted and more than ten novel genes differentially expressed were cloned. One is a deletion mutant of heterogeneous nuclear ribonucleoprotein (hnRNP) M4 in which the residues from 159 to 197 of hnRNP M4 have been absent. The deletion mutant was shown to be co-expressed with hnRNP M4 in cell lines. The mutant was expressed in antigen-stimulated DC but not in normal DC. Northern blot analysis revealed the presence of a major hnRNP M4 deletion mutant Mrna transcript of 2.4 kilobase with the highest levels in peripheral lymphocytes, lung, liver and spleen. It was also expressed in bone marrow-derived stromal cells (BMSC), BMSC treated with several cytokines but not in BMSC treated with TNF-a. The results revealed a new member of hnRNP family and suggested that hnRNP would participate in antigen process and presentation.

  8. A mathematical model of the current density distribution in electrochemical cells - AUTHORS’ REVIEW

    Directory of Open Access Journals (Sweden)

    PREDRAG M. ŽIVKOVIĆ

    2011-06-01

    Full Text Available An approach based on the equations of electrochemical kinetics for the estimation of the current density distribution in electrochemical cells is presented. This approach was employed for a theoretical explanation of the phenomena of the edge and corner effects. The effects of the geometry of the system, the kinetic parameters of the cathode reactions and the resistivity of the solution are also discussed. A procedure for a complete analysis of the current distribution in electrochemical cells is presented.

  9. Enzyme controlled glucose auto-delivery for high cell density cultivations in microplates and shake flasks

    Directory of Open Access Journals (Sweden)

    Casteleijn Marco G

    2008-11-01

    Full Text Available Abstract Background Here we describe a novel cultivation method, called EnBase™, or enzyme-based-substrate-delivery, for the growth of microorganisms in millilitre and sub-millilitre scale which yields 5 to 20 times higher cell densities compared to standard methods. The novel method can be directly applied in microwell plates and shake flasks without any requirements for additional sensors or liquid supply systems. EnBase is therefore readily applicable for many high throughput applications, such as DNA production for genome sequencing, optimisation of protein expression, production of proteins for structural genomics, bioprocess development, and screening of enzyme and metagenomic libraries. Results High cell densities with EnBase are obtained by applying the concept of glucose-limited fed-batch cultivation which is commonly used in industrial processes. The major difference of the novel method is that no external glucose feed is required, but glucose is released into the growth medium by enzymatic degradation of starch. To cope with the high levels of starch necessary for high cell density cultivation, starch is supplied to the growing culture suspension by continuous diffusion from a storage gel. Our results show that the controlled enzyme-based supply of glucose allows a glucose-limited growth to high cell densities of OD600 = 20 to 30 (corresponding to 6 to 9 g l-1 cell dry weight without the external feed of additional compounds in shake flasks and 96-well plates. The final cell density can be further increased by addition of extra nitrogen during the cultivation. Production of a heterologous triosphosphate isomerase in E. coli BL21(DE3 resulted in 10 times higher volumetric product yield and a higher ratio of soluble to insoluble product when compared to the conventional production method. Conclusion The novel EnBase method is robust and simple-to-apply for high cell density cultivation in shake flasks and microwell plates. The

  10. Heterogeneous populations of bone marrow stem cells--are we spotting on the same cells from the different angles?

    Directory of Open Access Journals (Sweden)

    Janina Ratajczak

    2004-10-01

    Full Text Available Accumulated evidence suggests that in addition to hematopoietic stem cells (HSC, bone marrow (BM also harbors endothelial stem cells (ESC, mesenchymal stem cells (MSC, multipotential adult progenitor cells (MAPC, pluripotent stem cells (PCS as well as tissue committed stem cells (TCSC recently identified by us. In this review we discuss the similarities and differences between these cell populations. Furthermore, we will present the hypothesis that all of these versatile BM derived stem cells are in fact different subpopulations of TCSC. These cells accumulate in bone marrow during ontogenesis and being a mobile population of cells are released from BM into peripheral blood after tissue injury to regenerate damaged organs. Furthermore, since BM is a "hideout" for TCSC, their presence in preparations of bone marrow derived mononuclear cells should be considered before experimental evidence is interpreted simply as trans-differentiation or plasticity of HSC. Finally, our observation that the number of TCSC accumulate in the bone marrow of young animals and their numbers decrease during senescence provides a new insight into aging and may explain why the regeneration processes becomes less effective in older individuals.

  11. Remarkable heterogeneity displayed by oval cells in rat and mouse models of stem cell-mediated liver regeneration

    DEFF Research Database (Denmark)

    Jelnes, Peter; Santoni-Rugiu, Eric; Rasmussen, Morten;

    2007-01-01

    The experimental protocols used in the investigation of stem cell-mediated liver regeneration in rodents are characterized by activation of the hepatic stem cell compartment in the canals of Hering followed by transit amplification of oval cells and their subsequent differentiation along hepatic...... the molecular phenotypes of oval cells in several of the most commonly used protocols of stem cell-mediated liver regeneration-namely, treatment with 2-acetylaminofluorene and partial (70%) hepatectomy (AAF/PHx); a choline-deficient, ethionine-supplemented (CDE) diet; a 3,5-diethoxycarbonyl-1...... results delineate remarkable phenotypic discrepancies exhibited by oval cells in stem cell-mediated liver regeneration between rats and mice and underline the importance of careful extrapolation between individual species....

  12. Heterogeneity in mouse seminal vesicle epithelial cells responding to androgen as evaluated by incorporation of [125I]iododeoxyuridine

    International Nuclear Information System (INIS)

    When the uptake of 5-[125I]iodo-2'-deoxyuridine ([125I]IdUrd) into the seminal vesicle of castrated mice was measured 3 days after starting injections of various doses of testosterone propionate (TP), logarithmic values of [125I]IdUrd uptake were proportional to the logarithmic doses of TP in the range of 0.04-2 micrograms/g BW. The [125I]IdUrd uptake values correlated well with the labeling and mitotic indices of epithelial cells. Since daily injections of 0.4 microgram TP/g BW did not increase significantly the weight or DNA content or protein content of the seminal vesicle, the [125I]IdUrd uptake is a sensitive index of androgen action. Moreover, this suggests that low doses of androgen induce division of epithelial cells without resulting in the increase in cell number. The [125I]IdUrd radioactivity in the seminal vesicle was measured 2-15 days after the injection of [125I]IdUrd, since the value represented the fraction of surviving cells synthesizing DNA at the time of [125I]IdUrd injection. When injections of 4 micrograms TP/g BW were continued, the incorporated radioactivity was retained. In contrast, continuous injections of 0.2 microgram TP/g BW did not maintain the radioactivity, of which incorporation was induced by the same dose of TP. Thus, the present result suggests the presence of heterogeneity in androgen-responsive epithelial cells of the seminal vesicle

  13. Heterogeneous nuclear ribonucleoprotein K upregulates the kinetochore complex component NUF2 and promotes the tumorigenicity of colon cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Sugimasa, Hironobu; Taniue, Kenzui [Laboratory of Molecular and Genetic Information, Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113-0032 (Japan); Kurimoto, Akiko [Laboratory of Molecular and Genetic Information, Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113-0032 (Japan); Oncology Research Laboratories, Daiichi Sankyo Co., Ltd, 1-2-58, Hiromachi, Shinagawa-ku, Tokyo, 140-8710 (Japan); Takeda, Yasuko; Kawasaki, Yoshihiro [Laboratory of Molecular and Genetic Information, Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113-0032 (Japan); Akiyama, Tetsu, E-mail: akiyama@iam.u-tokyo.ac.jp [Laboratory of Molecular and Genetic Information, Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113-0032 (Japan)

    2015-03-27

    Heterogeneous nuclear ribonucleoprotein K (hnRNP K) is a multi-functional protein involved in transcription, mRNA splicing, mRNA stabilization and translation. Although hnRNP K has been suggested to play a role in the development of many cancers, its molecular function in colorectal cancer has remained elusive. Here we show that hnRNP K plays an important role in the mitotic process in HCT116 colon cancer cells. Furthermore, we demonstrate that hnRNP K directly transactivates the NUF2 gene, the product of which is a component of the NDC80 kinetochore complex and which is known to be critical for a stable spindle microtubule-kinetochore attachment. In addition, knockdown of both hnRNP K and NUF2 caused failure in metaphase chromosome alignment and drastic decrease in the growth of colon cancer cells. These results suggest that the hnRNP K-NUF2 axis is important for the mitotic process and proliferation of colon cancer cells and that this axis could be a target for the therapy of colon cancer. - Highlights: • hnRNP K is required for the tumorigenicity of colon cancer cells. • hnRNP K binds to the promoter region of NUF2 and activates its transcription. • NUF2 expression is correlated with hnRNP K expression in colorectal cancer tissue. • hnRNP K and NUF2 are required for metaphase chromosome alignment. • The hnRNP K-NUF2 axis is important for the proliferation of colon cancer cells.

  14. Heterogeneous nuclear ribonucleoprotein K upregulates the kinetochore complex component NUF2 and promotes the tumorigenicity of colon cancer cells

    International Nuclear Information System (INIS)

    Heterogeneous nuclear ribonucleoprotein K (hnRNP K) is a multi-functional protein involved in transcription, mRNA splicing, mRNA stabilization and translation. Although hnRNP K has been suggested to play a role in the development of many cancers, its molecular function in colorectal cancer has remained elusive. Here we show that hnRNP K plays an important role in the mitotic process in HCT116 colon cancer cells. Furthermore, we demonstrate that hnRNP K directly transactivates the NUF2 gene, the product of which is a component of the NDC80 kinetochore complex and which is known to be critical for a stable spindle microtubule-kinetochore attachment. In addition, knockdown of both hnRNP K and NUF2 caused failure in metaphase chromosome alignment and drastic decrease in the growth of colon cancer cells. These results suggest that the hnRNP K-NUF2 axis is important for the mitotic process and proliferation of colon cancer cells and that this axis could be a target for the therapy of colon cancer. - Highlights: • hnRNP K is required for the tumorigenicity of colon cancer cells. • hnRNP K binds to the promoter region of NUF2 and activates its transcription. • NUF2 expression is correlated with hnRNP K expression in colorectal cancer tissue. • hnRNP K and NUF2 are required for metaphase chromosome alignment. • The hnRNP K-NUF2 axis is important for the proliferation of colon cancer cells

  15. Evidence for osmoregulation of cell growth and buoyant density in Escherichia coli.

    OpenAIRE

    Baldwin, W W; Kubitschek, H. E.

    1984-01-01

    The buoyant density of cells of Escherichia coli B/r NC32 increased with the osmolarity of the growth medium. Growth rate and its variability were also dependent upon the osmolarity of the medium. Maximum growth rates and minimum variability of these rates were obtained in Luria broth by addition of NaCl to a concentration of about 0.23 M.

  16. Accurate assessment of cell density in low cellular liquid-based cervical cytology

    NARCIS (Netherlands)

    Siebers, A.G.; Laak, J.A.W.M. van der; Huberts-Manders, R.; Vedder, J.E.M.; Bulten, J.

    2013-01-01

    A. G. Siebers, J. A. W. M. van der Laak, R. Huberts-Manders, J. E. M. Vedder and J. Bulten Accurate assessment of cell density in low cellular liquid-based cervical cytology Objective: Scant cellularity is the most important source of unsatisfactory liquid-based cytology. Although still being debate

  17. Stomatal and pavement cell density linked to leaf internal CO2 concentration

    Czech Academy of Sciences Publication Activity Database

    Šantrůček, Jiří; Vráblová, M.; Šimková, Marie; Hronková, Marie; Drtinová, M.; Květoň, J.; Vrábl, D.; Kubásek, J.; Macková, J.; Wiesnerová, Dana; Neuwithová, J.; Schreiber, L.

    2014-01-01

    Roč. 114, č. 2 (2014), s. 191-202. ISSN 0305-7364 R&D Projects: GA ČR(CZ) GAP501/12/1261 Institutional support: RVO:60077344 Keywords : Stomatal density * Stomata development * Pavement cells Subject RIV: CE - Biochemistry Impact factor: 3.654, year: 2014

  18. Vascular smooth muscle cells in cultures on low density polyethylene modified with plasma discharge and biofunctionalization

    Czech Academy of Sciences Publication Activity Database

    Pařízek, Martin; Kasálková, N.; Bačáková, Lucie; Kolářová, K.; Lisá, Věra; Švorčík, V.

    2009-01-01

    Roč. 12, 89-91 (2009), s. 25-28. ISSN 1429-7248 R&D Projects: GA AV ČR(CZ) KAN400480701; GA AV ČR(CZ) 1QS500110564 Institutional research plan: CEZ:AV0Z50110509 Keywords : Ar plasma discharge * low density polyethylene * vascular smooth muscle cells Subject RIV: EI - Biotechnology ; Bionics

  19. High Performance Ultrathin GaAs Solar Cells Enabled with Heterogeneously Integrated Dielectric Periodic Nanostructures.

    Science.gov (United States)

    Lee, Sung-Min; Kwong, Anthony; Jung, Daehwan; Faucher, Joseph; Biswas, Roshni; Shen, Lang; Kang, Dongseok; Lee, Minjoo Larry; Yoon, Jongseung

    2015-10-27

    Due to their favorable materials properties including direct bandgap and high electron mobilities, epitaxially grown III-V compound semiconductors such as gallium arsenide (GaAs) provide unmatched performance over silicon in solar energy harvesting. Nonetheless, their large-scale deployment in terrestrial photovoltaics remains challenging mainly due to the high cost of growing device quality epitaxial materials. In this regard, reducing the thickness of constituent active materials under appropriate light management schemes is a conceptually viable option to lower the cost of GaAs solar cells. Here, we present a type of high efficiency, ultrathin GaAs solar cell that incorporates bifacial photon management enabled by techniques of transfer printing to maximize the absorption and photovoltaic performance without compromising the optimized electronic configuration of planar devices. Nanoimprint lithography and dry etching of titanium dioxide (TiO2) deposited directly on the window layer of GaAs solar cells formed hexagonal arrays of nanoscale posts that serve as lossless photonic nanostructures for antireflection, diffraction, and light trapping in conjunction with a co-integrated rear-surface reflector. Systematic studies on optical and electrical properties and photovoltaic performance in experiments, as well as numerical modeling, quantitatively describe the optimal design rules for ultrathin, nanostructured GaAs solar cells and their integrated modules. PMID:26376087

  20. Single-cell sequencing reveals karyotype heterogeneity in murine and human malignancies

    NARCIS (Netherlands)

    Bakker, Bjorn; Taudt, Aaron; Belderbos, Mirjam E.; Porubsky, David; Spierings, Diana C. J.; de Jong, Tristan V.; Halsema, Nancy; Kazemier, Hinke G.; Hoekstra-Wakker, Karina; Bradley, Allan; de Bont, Eveline S. J. M.; van den Berg, Anke; Guryev, Victor; Lansdorp, Peter M.; Colome-Tatche, Maria; Foijer, Floris

    2016-01-01

    Background: Chromosome instability leads to aneuploidy, a state in which cells have abnormal numbers of chromosomes, and is found in two out of three cancers. In a chromosomal instable p53 deficient mouse model with accelerated lymphomagenesis, we previously observed whole chromosome copy number cha

  1. Combined Impact of Heterogeneous Lifetime and Gettering on Solar Cell Performance

    Energy Technology Data Exchange (ETDEWEB)

    Morishige, A.; Wagner, H.; Hofstetter, J.; Avci, I.; Canizo, C.; Buonassisi, T.

    2015-03-23

    We couple numerical process and device simulations to provide a framework for understanding the combined effects of as-grown wafer impurity distribution, processing parameters, and solar cell architecture. For this study, we added the Impurity-to-Efficiency simulator to Synopsys’ Sentaurus Process software using the Alagator Scripting Language. Our results quantify how advanced processing can eliminate differences in efficiency due to different as-grown impurity concentrations and due to different area fractions of defective wafer regions. We identify combinations of as-grown impurity distributions and process parameters that produce solar cells limited by point defects and those that are limited by precipitated impurities. Gettering targeted at either point defect or precipitate reduction can then be designed and applied to increase cell efficiency. We also visualize the post-processing iron and total recombination distributions in 2D maps of the wafer cross-section. PV researchers and companies can input their initial iron distributions and processing parameters into our software and couple the resulting process simulation results with a solar cell device design of interest to conduct their own analyses. The Alagator scripts we developed are freely available online at http://pv.mit.edu/impurity-to-efficiency-i2e-simulator-for-sentaurus-tcad/.

  2. The human CD77- B cell population represents a heterogeneous subset of cells comprising centroblasts, centrocytes, and plasmablasts, prompting phenotypical revision.

    Science.gov (United States)

    Högerkorp, Carl-Magnus; Borrebaeck, Carl A K

    2006-10-01

    The process of becoming an Ig-producing plasma cell takes the mature B cell through the germinal center, where Ig genes are diversified through somatic hypermutation and class switch recombination. To more clearly define functional characteristics of the germinal center dark zone centroblasts and the light zone centrocytes, we have performed expression analysis of the CD77(+) and CD77(-) populations, because CD77 has been accepted as a discriminator of centroblasts and centrocytes. Our results demonstrated that the CD77(+) and the CD77(-) populations lack functional associated expression programs discriminating the two populations. Both populations are shown to be actively cycling and to share common features associated with cell cycle regulation and DNA maintenance. They are also shown to have an equally active DNA repair program, as well as components involved in somatic hypermutation and class switch recombination. Moreover, the data also demonstrated that the CD77(-) population comprises cells with an already initiated plasma cell differentiation program. Together this demonstrates that CD77 does not discriminate centroblasts and centrocytes and that the CD77(-) population represents a heterogeneous subset of cells, comprising centroblasts, centrocytes, and plasmablast. PMID:16982868

  3. Lysosomal and endosomal heterogeneity in the liver: A comparison of the intracellular pathways of endocytosis in rat liver cells

    International Nuclear Information System (INIS)

    Air-filled albumin microspheres, asialoorosomucoid and formaldehyde-treated serum albumin are selectively taken up by endocytosis in rat liver Kupffer cells, parenchymal cells and endothelial cells, respectively. Intracellular transport and degradation of endocytosed material were studied by subcellular fractionation in sucrose and Nycodenz gradients after intravenous injection of the ligand. By using ligands labeled with 125I-tyramine-cellobiose, the subcellular distribution of labeled degradation products can be studied because they are trapped at the site of formation. The results show that the kinetics of intracellular transport are different in hepatic parenchymal, endothelial and Kupffer cells. In endothelial cells, the ligand is associated with two types of endosomes during the first minutes after internalization and then is transferred rapidly to the lysosomes. In parenchymal cells, 125I-tyramine-cellobiose-asialoorosomucoid was located in a relatively slowly sedimenting vesicle during the first minute after internalization and subsequently in denser endosomes. Degradation of 125I-tyramine-cellobiose-asialoorosomucoid in parenchymal cells started later than that of 125I-tyramine-cellobiose-formaldehyde-treated serum albumin in endothelial cells. Furthermore, the ligand seemed to be transferred relatively slowly from endosomes to lysosomes, and most of the undegraded ligand was in the endosomes. The rate-limiting step of proteolysis in parenchymal cells is probably the transport from endosomes to lysosomes. In Kupffer cells, most 125I-tyramine-cellobiose-microspheres are found as undegraded material in very dense endosomes up to 3 hr after injection. After 20 hr, most of the ligand is degraded in lysosomes distributed at a lower density than the endosomes in Nycodenz and sucrose gradients

  4. Performance Analysis of enhanced Inter-cell Interference Coordination in LTE-Advanced Heterogeneous Networks

    DEFF Research Database (Denmark)

    Wang, Yuanye; Pedersen, Klaus I.

    2012-01-01

    The performance of enhanced Inter-Cell Interference Coordination (eICIC) for Long Term Evolution (LTE)- Advanced with co-channel deployment of both macro and pico is analyzed. The use of pico-cell Range Extension (RE) and time domain eICIC (TDM muting) is combined. The performance is evaluated in...... the downlink by means of extensive system level simulations that follow the 3GPP guidelines. The overall network performance is analyzed for different number of pico-eNBs, transmit power levels, User Equipment (UE) distributions, and packet schedulers. Recommended settings of the RE offset and TDM...... muting ratio in different scenarios are identified. The presented performance results and findings can serve as input to guidelines for co-channel deployment of macro and pico-eNBs with eICIC....

  5. A novel planar flow cell for studies of biofilm heterogeneity and flow-biofilm interactions

    OpenAIRE

    Zhang, Wei; Sileika, Tadas S.; Chen, Cheng; Liu, Yang; Lee, Jisun; Packman, Aaron I.

    2011-01-01

    Biofilms are microbial communities growing on surfaces, and are ubiquitous in nature, in bioreactors, and in human infection. Coupling between physical, chemical, and biological processes is known to regulate the development of biofilms; however, current experimental systems do not provide sufficient control of environmental conditions to enable detailed investigations of these complex interactions. We developed a novel planar flow cell that supports biofilm growth under complex two-dimension...

  6. More challenges ahead-metabolic heterogeneity of pancreatic cancer stem cells.

    Science.gov (United States)

    Heeschen, Christopher; Sancho, Patricia

    2016-03-01

    Pancreatic cancer stem cells (CSCs) display a distinct metabolic phenotype based on their strong dependence on mitochondrial oxidative phosphorylation (OXPHOS) and limited metabolic plasticity. While suppression of MYC upstream of PGC-1α was the key determinant of this phenotype, we also identified a subset of CSCs with reduced mitochondrial content that showed resistance to mitochondrial targeting, but could be sensitized by inhibition of MYC. PMID:27308630

  7. Heterogeneity of Astrocytes: From Development to Injury - Single Cell Gene Expression

    Czech Academy of Sciences Publication Activity Database

    Rusňáková, Vendula; Honsa, Pavel; Džamba, Dávid; Stahlberg, A.; Kubista, Mikael; Anděrová, Miroslava

    2013-01-01

    Roč. 8, č. 8 (2013), e69734. E-ISSN 1932-6203 R&D Projects: GA ČR GA13-02154S Institutional research plan: CEZ:AV0Z50520701; CEZ:AV0Z50390703 Keywords : Single cell expression profiling * astrocytes * GenEx Subject RIV: EB - Genetics ; Molecular Biology; FH - Neurology (UEM-P) Impact factor: 3.534, year: 2013

  8. LU Decomposition on Cell Broadband Engine: An Empirical Study to Exploit Heterogeneous Chip Multiprocessors

    OpenAIRE

    Mao, Feng; Shen, Xipeng

    2010-01-01

    To meet the needs of high performance computing, the Cell Broadband Engine owns many features that differ from traditional processors, such as the large number of synergistic processor elements, large register files, the ability to hide main-storage latency with concurrent computation and DMA transfers. The exploitation of those features requires the programmer to carefully tailor programs and simutaneously deal with various performance factors, including locality, load balance, communication...

  9. Heterogeneity of cell-associated CP5 expression on Staphylococcus aureus strains demonstrated by flow cytometry.

    OpenAIRE

    POUTREL, B.; Rainard, P; Sarradin, P.

    1997-01-01

    It was reported previously that two capsular polysaccharides, types 5 and 8 (CP5 and CP8), account for 70 to 80% of Staphylococcus aureus strains isolated from human and animal sources. The capsular material has been shown to play a part in virulence and in resistance to phagocytosis. With a view to investigating the role that CP plays in pathogenicity or protection, relative measurement of cell-associated CP is desirable. Flow cytometry, which permits the analysis of individual bacteria, was...

  10. A High Power-Density Mediator-Free Microfluidic Biophotovoltaic Device for Cyanobacterial Cells

    CERN Document Server

    Bombelli, Paolo; Herling, Therese W; Howe, Christopher J; Knowles, Tuomas P J

    2014-01-01

    Biophotovoltaics has emerged as a promising technology for generating renewable energy since it relies on living organisms as inexpensive, self-repairing and readily available catalysts to produce electricity from an abundant resource - sunlight. The efficiency of biophotovoltaic cells, however, has remained significantly lower than that achievable through synthetic materials. Here, we devise a platform to harness the large power densities afforded by miniaturised geometries. To this effect, we have developed a soft-lithography approach for the fabrication of microfluidic biophotovoltaic devices that do not require membranes or mediators. Synechocystis sp. PCC 6803 cells were injected and allowed to settle on the anode, permitting the physical proximity between cells and electrode required for mediator-free operation. We demonstrate power densities of above 100 mW/m2 for a chlorophyll concentration of 100 {\\mu}M under white light, a high value for biophotovoltaic devices without extrinsic supply of additional...

  11. CB-09THE CELL OF ORIGIN FOR GLIOBLASTOMA CONTRIBUTES TO THE PHENOTYPIC HETEROGENEITY OF GLIOMA STEM CELLS

    Science.gov (United States)

    Jiang, Yiwen; Marinescu, Voichita D.; Xie, Yuan; Haglund, Caroline; Jarvius, Malin; Lindberg, Nanna; Olofsson, Tommie; Hesselager, Göran; Alafuzoff, Irina; Fryknäs, Mårten; Larsson, Rolf; Nelander, Sven; Uhrbom, Lene

    2014-01-01

    Glioblastoma Multiforme (GBM) is the most frequent adult primary malignant brain tumor that remains incurable despite aggressive treatment. The cell of origin (COO) for GBM is unknown but assumed to be a glial stem or progenitor cell. GBM harbours hierarchical tumor cells called glioma stem cells (GSCs) that maintain tumor growth, drive tumor progression and cause tumor relapse due to their increased resistance to therapy. We have analyzed the significance of cellular origin for GBM development and GSC properties by comparing mouse GBMs and GSCs derived thereof induced in neural stem cells (NSCs), glial-restricted precursor cells (GPCs) or oligodendrocyte precursor cells (OPCs) by identical mutations. There were striking differences in GBM development and the phenotypes of GSCs and their response to drugs owing to the COO. Global gene expression analysis of mouse GSC lines displayed a clear separation due to COO and differential gene expression analysis identified a COO gene signature of 175 genes. Cross-species bioinformatics analyses were performed. First we analyzed the human cancer genome atlas (TCGA) GBM tissue samples and the mouse GSC expression data for a collection of TCGA GBM subtype signature genes. This showed that we could model both Proneural and Mesenchymal GBMs in mice by merely switching the COO. Next, we used the mouse COO gene signature to stratify a large number of newly established human glioma stem cell lines. This produced two groups of human GSCs; the NSC origin group and the progenitor cell (PC) origin group in which the mouse GPC- and OPC-derived genes were combined. Importantly, patient survival was significantly different between the NSC and PC COO groups with a better prognosis for the PC group patients. Thus, the cell of origin is essential for GBM biology and needs to be considered for more accurate patient stratification, target identification and drug discovery.

  12. Uptake of synthetic Low Density Lipoprotein by leukemic stem cells--a potential stem cell targeted drug delivery strategy.

    Science.gov (United States)

    Zhou, Peixun; Hatziieremia, Sophia; Elliott, Moira A; Scobie, Linda; Crossan, Claire; Michie, Alison M; Holyoake, Tessa L; Halbert, Gavin W; Jørgensen, Heather G

    2010-12-20

    Chronic Myeloid Leukemia (CML) stem/progenitor cells, which over-express Bcr-Abl, respond to imatinib by a reversible block in proliferation without significant apoptosis. As a result, patients are unlikely to be cured owing to the persistence of leukemic quiescent stem cells (QSC) capable of initiating relapse. Previously, we have reported that intracellular levels of imatinib in primary primitive CML cells (CD34+38(lo/⁻)), are significantly lower than in CML progenitor cells (total CD34+) and leukemic cell lines. The aim of this study was to determine if potentially sub-therapeutic intracellular drug concentrations in persistent leukemic QSC may be overcome by targeted drug delivery using synthetic Low Density Lipoprotein (sLDL) particles. As a first step towards this goal, however, the extent of uptake of sLDL by leukemic cell lines and CML patient stem/progenitor cells was investigated. Results with non-drug loaded particles have shown an increased and preferential uptake of sLDL by Bcr-Abl positive cell lines in comparison to Bcr-Abl negative. Furthermore, CML CD34+ and primitive CD34+38(lo/⁻) cells accumulated significantly higher levels of sLDL when compared with non-CML CD34+ cells. Thus, drug-loading the sLDL nanoparticles could potentially enhance intracellular drug concentrations in primitive CML cells and thus aid their eradication. PMID:20869412

  13. Limited genomic heterogeneity of circulating melanoma cells in advanced stage patients

    International Nuclear Information System (INIS)

    Purpose. Circulating melanoma cells (CMCs) constitute a potentially important representation of time-resolved tumor biology in patients. To date, genomic characterization of CMCs has been limited due to the lack of a robust methodology capable of identifying them in a format suitable for downstream characterization. Here, we have developed a methodology to detect intact CMCs that enables phenotypic, morphometric and genomic analysis at the single cell level. Experimental design. Blood samples from 40 metastatic melanoma patients and 10 normal blood donors were prospectively collected. A panel of 7 chondroitin sulfate proteoglycan 4 (CSPG4)-specific monoclonal antibodies (mAbs) was used to immunocytochemically label CMCs. Detection was performed by automated digital fluorescence microscopy and multi-parametric computational analysis. Individual CMCs were captured by micromanipulation for whole genome amplification and copy number variation (CNV) analysis. Results. Based on CSPG4 expression and nuclear size, 1–250 CMCs were detected in 22 (55%) of 40 metastatic melanoma patients (0.5–371.5 CMCs ml−1). Morphometric analysis revealed that CMCs have a broad spectrum of morphologies and sizes but exhibit a relatively homogeneous nuclear size that was on average 1.5-fold larger than that of surrounding PBMCs. CNV analysis of single CMCs identified deletions of CDKN2A and PTEN, and amplification(s) of TERT, BRAF, KRAS and MDM2. Furthermore, novel chromosomal amplifications in chr12, 17 and 19 were also found. Conclusions. Our findings show that CSPG4 expressing CMCs can be found in the majority of advanced melanoma patients. High content analysis of this cell population may contribute to the design of effective personalized therapies in patients with melanoma. (paper)

  14. Anatomical Mapping and Density of Merkel Cells in Skin and Mucosae of the Dog.

    Science.gov (United States)

    Ramírez, Gustavo A; Rodríguez, Francisco; Quesada, Óscar; Herráez, Pedro; Fernández, Antonio; Espinosa-de-Los-Monteros, Antonio

    2016-09-01

    Merkel cells (MCs) are specialized cutaneous receptor cells involved with tactile sense. Although the distribution of MCs has been extensively studied in humans and rodents, their precise distribution and density throughout skin in the dog has not previously been determined. Knowledge of their distribution could facilitate understanding of their functions. By using of immunohistochemistry, density, and anatomical mapping of the MCs population in the dog skin was determined. Assessment of the MCs innervation was also achieved. Different patterns were noted in epidermis, hair follicles, or mucosa, including variable-sized clusters, linear or horse-shaped arrangements, and scattered and individualized cells. MCs revealed great variations in density and distribution over the body surface, with the highest numbers in oral mucosa and facial skin. There was no correlation of MCs density with age, sex, type of breed, coat type or pigmentation. Between 41 and 65% of MCs in hairy and glabrous skin and 8-18% of MCs in oral mucosa were in intimate contact with intraepithelial axon terminals. These findings indicate that canine MCs are numerous in sensory receptive areas and may be associated with the tactile sense in the dog. The present article enhances the knowledge of the skin structure in this species. Anat Rec, 299:1157-1164, 2016. © 2016 Wiley Periodicals, Inc. PMID:27341526

  15. Tumorigenic heterogeneity in cancer stem cells evolved from long-term cultures of telomerase-immortalized human mesenchymal stem cells

    DEFF Research Database (Denmark)

    Burns, Jorge S; Abdallah, Basem M; Guldberg, Per;

    2005-01-01

    or if the stem cell origin allowed most cells to behave as cancer stem cells. Cultures of the hMSC-TERT20 strain at population doubling 440 were highly clonogenic (94%). From 110 single-cell clones expanded by 20 population doublings, 6 underwent detailed comparison. Like the parental population, each clone had...... approximately 1.2 days doubling time with loss of contact inhibition. All retained 1,25-(OH)(2) vitamin D(3)-induced expression of osteoblastic markers: collagen type I, alkaline phosphatase, and osteocalcin. All shared INK4a/ARF gene locus deletion and epigenetic silencing of the DBCCR1 tumor suppressor gene....... Despite in vitro commonality, only four of six clones shared the growth kinetics and 100% tumorigenicity of the parental population. In contrast, one clone consistently formed latent tumors and the other established tumors with only 30% penetrance. Changing the in vitro microenvironment to mimic in vivo...

  16. Increased cell proliferation and mucocyte density in the sea anemone Aiptasia pallida recovering from bleaching.

    Directory of Open Access Journals (Sweden)

    David Fransolet

    Full Text Available Recovery of coral after bleaching episodes is a critical period for the health of the reef ecosystem. While events such as symbiont (genus Symbiodinium shifting/shuffling or tissue apoptosis have been demonstrated to occur following bleaching, little is known concerning tissue recovery or cell proliferation. Here, we studied the sea anemone Aiptasia pallida exposed to a transient elevation of water temperature combined with high illumination (33°C and 1900 µmol photons x m(-2 x s(-1 for 30 h. Following such treatment bleached anemones showed a significant reduction of their Symbiodinium density. Cell proliferation in the ectodermis and gastrodermis was determined by assessing the densities of cells labeled with a thymidine analogue (EdU. Cell proliferation significantly increased during the first day following stress in both tissue types. This increased cell proliferation returned to pre-stress values after one week. Although cell proliferation was higher in the ectodermis in absence of stress, it was relatively more pronounced in the gastrodermis of stressed anemones. In addition, the ratio of ectodermal mucocytes significantly increased three weeks after induced stress. These results suggest that thermal/photic stress coupled with the loss of the symbionts is able to enhance cell proliferation in both gastrodermis and ectodermis of cnidarians. While new cells formed in the gastrodermis are likely to host new Symbiodinium, the fate of new cells in the ectodermis was only partially revealed. Some new ectodermal cells may, in part, contribute to the increased number of mucocytes which could eventually help strengthen the heterotrophic state until restoration of the symbiosis.

  17. All or none cell responses of Ca2+-dependent K channels elicited by calcium or lead in human red cells can be explained by heterogeneity of agonist distribution

    International Nuclear Information System (INIS)

    We have studied the all or none cell response of Ca2+-dependent K+ channels to added Ca in human red cells depleted of ATP by incubation with iodoacetate and inosine. A procedure was used which allows separation and differential analysis of responding and nonresponding cells. Responding (H for heavy) cells incubated in medium containing 5 mM K lose KCl and water and increase their density to the point of sinking on diethylphthalate (specific gravity = 1.12) on centrifugation. Nonresponding (L for light) cells do not lose KCl at all. There is no intermediate behavior. Increasing the Ca concentration in the medium increases the fraction of cells which become H. No differences in the sensitivity to Ca2+ of the individual K+ channels were detected in inside-out vesicles prepared either from H or from L cells. The Ca content of H cells was higher than that of L cells. Cells depleted of ATP by incubation with iodoacetate and inosine sustain pump-leak Ca fluxes of about 15 mumol/liter cells per hour. ATP seems to be resynthesized in these cells at the expense of cell 2,3-diphosphoglycerate stores at a rate of about 150 mumol/liter cells per hour. Inhibition of 2,3-diphosphoglycerate phosphatase by tetrathionate increased 6-8 times the measured rate of uptake of external 45Ca. This was accompanied by an increase in the fraction of H cells. All or none cell responses of Ca2+-dependent K channels have also been evidenced in intact human red cells on addition of Pb. They have the same characteristics as those in responding and nonresponding cells. The detailed study of the kinetics of Pb-induced shrinkage of red cells suspended in medium containing 5 mM K showed that changes of Pb concentration changed not only the fraction of H cells but also the rate of shrinkage of responding cells. H cells generated by Pb treatment contained significantly more lead than L cells

  18. A device to facilitate preparation of high-density neural cell cultures in MEAs.

    Science.gov (United States)

    Mok, S Y; Lim, Y M; Goh, S Y

    2009-05-15

    A device to facilitate high-density seeding of dissociated neural cells on planar multi-electrode arrays (MEAs) is presented in this paper. The device comprises a metal cover with two concentric cylinders-the outer cylinder fits tightly on to the external diameter of a MEA to hold it in place and an inner cylinder holds a central glass tube for introducing a cell suspension over the electrode area of the MEA. An O-ring is placed at the bottom of the inner cylinder and the glass tube to provide a fluid-tight seal between the glass tube and the MEA electrode surface. The volume of cell suspension in the glass tube is varied according to the desired plating density. After plating, the device can be lifted from the MEA without leaving any residue on the contact surface. The device has enabled us to increase and control the plating density of neural cell suspension with low viability, and to prepare successful primary cultures from cryopreserved neurons and glia. The cultures of cryopreserved dissociated cortical neurons that we have grown in this manner remained spontaneously active over months, exhibited stable development and similar network characteristics as reported by other researchers. PMID:19428539

  19. Heterogeneous Catalysis

    OpenAIRE

    Schlögl, R.

    2015-01-01

    A heterogeneous catalyst is a functional material that continually creates active sites with its reactants under reaction conditions. These sites change the rates of chemical reactions of the reactants localized on them without changing the thermodynamic equilibrium between the materials.

  20. Heterogeneous Catalysis.

    Science.gov (United States)

    Miranda, R.

    1989-01-01

    Described is a heterogeneous catalysis course which has elements of materials processing embedded in the classical format of catalytic mechanisms and surface chemistry. A course outline and list of examples of recent review papers written by students are provided. (MVL)

  1. Heterogeneous Differentiation of Human Mesenchymal Stem Cells in 3D Extracellular Matrix Composites

    Science.gov (United States)

    Jung, Jangwook P.; Bache-Wiig, Meredith K.; Provenzano, Paolo P.; Ogle, Brenda M.

    2016-01-01

    Abstract Extracellular matrix (ECM) proteins are structural elements of tissue and also potent signaling molecules. Previously, our laboratory showed that ECM of 2D coatings can trigger differentiation of bone marrow-derived mesenchymal stem cells (MSCs) into mesodermal lineages in an ECM-specific manner over 14 days, in some cases comparable to chemical induction. To test whether a similar effect was possible in a 3D, tissue-like environment, we designed a synthetic-natural biomaterial composite. The composite can present whole-molecule ECM proteins to cells, even those that do not spontaneously form hydrogels ex vivo, in 3D. To this end, we entrapped collagen type I, laminin-111, or fibronectin in ECM composites with MSCs and directly compared markers of mesodermal differentiation including cardiomyogenic (ACTC1), osteogenic (SPP1), adipogenic (PPARG), and chondrogenic (SOX9) in 2D versus 3D. We found the 3D condition largely mimicked the 2D condition such that the addition of type I collagen was the most potent inducer of differentiation to all lineages tested. One notable difference between 2D and 3D was pronounced adipogenic differentiation in 3D especially in the presence of exogenous collagen type I. In particular, PPARG gene expression was significantly increased ∼16-fold relative to chemical induction, in 3D and not in 2D. Unexpectedly, 3D engagement of ECM proteins also altered immunomodulatory function of MSCs in that expression of IL-6 gene was elevated relative to basal levels in 2D. In fact, levels of IL-6 gene expression in 3D composites containing exogenously supplied collagen type I or fibronectin were statistically similar to levels attained in 2D with tumor necrosis factor-α (TNF-α) stimulation and these levels were sustained over a 2-week period. Thus, this novel biomaterial platform allowed us to compare the biochemical impact of whole-molecule ECM proteins in 2D versus 3D indicating enhanced adipogenic differentiation and IL-6 expression

  2. Wolbachia induces density-dependent inhibition to dengue virus in mosquito cells.

    Directory of Open Access Journals (Sweden)

    Peng Lu

    Full Text Available Wolbachia is a maternal transmitted endosymbiotic bacterium that is estimated to infect up to 65% of insect species. The ability of Wolbachia to both induce viral interference and spread into mosquito vector population makes it possible to develop Wolbachia as a biological control agent for dengue control. While Wolbachia induces resistance to dengue virus in the transinfected Aedes aegypti mosquitoes, a similar effect was not observed in Aedes albopictus, which naturally carries Wolbachia infection but still serves as a dengue vector. In order to understand the mechanism of this lack of Wolbachia-mediated viral interference, we used both Ae. albopictus cell line (Aa23 and mosquitoes to characterize the impact of Wolbachia on dengue infection. A serial of sub-lethal doses of antibiotic treatment was used to partially remove Wolbachia in Aa23 cells and generate cell cultures with Wolbachia at different densities. We show that there is a strong negative linear correlation between the genome copy of Wolbachia and dengue virus with a dengue infection completely removed when Wolbacha density reaches a certain level. We then compared Wolbachia density between transinfected Ae. aegypti and naturally infected Ae. albopictus. The results show that Wolbachia density in midgut, fatbody and salivary gland of Ae. albopictus is 80-, 18-, and 24-fold less than that of Ae. aegypti, respectively. We provide evidence that Wolbachia density in somatic tissues of Ae. albopictus is too low to induce resistance to dengue virus. Our results will aid in understanding the mechanism of Wolbachia-mediated pathogen interference and developing novel methods to block disease transmission by mosquitoes carrying native Wolbachia infections.

  3. CD44 isoforms are heterogeneously expressed in breast cancer and correlate with tumor subtypes and cancer stem cell markers

    International Nuclear Information System (INIS)

    The CD44 cell adhesion molecule is aberrantly expressed in many breast tumors and has been implicated in the metastatic process as well as in the putative cancer stem cell (CSC) compartment. We aimed to investigate potential associations between alternatively spliced isoforms of CD44 and CSCs as well as to various breast cancer biomarkers and molecular subtypes. We used q-RT-PCR and exon-exon spanning assays to analyze the expression of four alternatively spliced CD44 isoforms as well as the total expression of CD44 in 187 breast tumors and 13 cell lines. ALDH1 protein expression was determined by IHC on TMA. Breast cancer cell lines showed a heterogeneous expression pattern of the CD44 isoforms, which shifted considerably when cells were grown as mammospheres. Tumors characterized as positive for the CD44+/CD24- phenotype by immunohistochemistry were associated to all isoforms except the CD44 standard (CD44S) isoform, which lacks all variant exons. Conversely, tumors with strong expression of the CSC marker ALDH1 had elevated expression of CD44S. A high expression of the CD44v2-v10 isoform, which retain all variant exons, was correlated to positive steroid receptor status, low proliferation and luminal A subtype. The CD44v3-v10 isoform showed similar correlations, while high expression of CD44v8-v10 was correlated to positive EGFR, negative/low HER2 status and basal-like subtype. High expression of CD44S was associated with strong HER2 staining and also a subgroup of basal-like tumors. Unsupervised hierarchical cluster analysis of CD44 isoform expression data divided tumors into four main clusters, which showed significant correlations to molecular subtypes and differences in 10-year overall survival. We demonstrate that individual CD44 isoforms can be associated to different breast cancer subtypes and clinical markers such as HER2, ER and PgR, which suggests involvement of CD44 splice variants in specific oncogenic signaling pathways. Efforts to link CD44 to CSCs

  4. Computer Simulation of Mutual Synchronization of Cell Density Oscillations of Hyperproliferating Epidermisis in Psoriasis Pathogenesis

    Directory of Open Access Journals (Sweden)

    М.V. Laptev

    2012-06-01

    Full Text Available The aim of the investigation is to study theoretically the patterns of mutual synchronization of epidermal cell density oscillations in psoriatic skin lesions, particularly under conditions of severe clipped noise, and to evaluate its role in the pathogenesis of some clinical forms of the disease. Matherials and Methods. A pre-designed mathematical model of autocrine and paracrine regulation of psoriatic epidermal proliferation is used as the objects of the study. The study was carried out on a personal computer using a mathematical software package Mathcad 14. Results. The study showed a tendency to form in the diffusion-related of psoriatic skin lesions characterized by self-oscillations of epidermal cell density, the group wholly or partially synchronized elements. The final result depended on the noise level, the distribution of power relations, and the relation of frequencies and oscillations amplitudes. The patterns can explain the development of such forms of the disease, as figured, limited and generalized psoriasis.

  5. Lectin-like oxidized low-density lipoprotein receptor (LOX-1) in sickle cell disease vasculopathy.

    Science.gov (United States)

    Chen, Mingyi; Qiu, Hong; Lin, Xin; Nam, David; Ogbu-Nwobodo, Lucy; Archibald, Hannah; Joslin, Amelia; Wun, Ted; Sawamura, Tatsuya; Green, Ralph

    2016-09-01

    Lectin-like oxidized low-density lipoprotein (LDL) receptor-1 (LOX-1) is an endothelial receptor for oxidized LDL. Increased expression of LOX-1 has been demonstrated in atherosclerotic lesions and diabetic vasculopathy. In this study, we investigate the expression of LOX-1 receptor in sickle cell disease (SCD) vasculopathy. Expression of LOX-1 in brain vascular endothelium is markedly increased and LOX-1 gene expression is upregulated in cultured human brain microvascular endothelial cells by incubation with SCD erythrocytes. Also, the level of circulating soluble LOX-1 concentration is elevated in the plasma of SCD patients. Increased LOX-1 expression in endothelial cells is potentially involved in the pathogenesis of SCD vasculopathy. Soluble LOX-1 concentration in SCD may provide a novel biomarker for risk stratification of sickle cell vascular complications. PMID:27519944

  6. Scanning STED-FCS reveals spatiotemporal heterogeneity of lipid interaction in the plasma membrane of living cells

    Science.gov (United States)

    Honigmann, Alf; Mueller, Veronika; Ta, Haisen; Schoenle, Andreas; Sezgin, Erdinc; Hell, Stefan W.; Eggeling, Christian

    2014-11-01

    The interaction of lipids and proteins plays an important role in plasma membrane bioactivity, and much can be learned from their diffusion characteristics. Here we present the combination of super-resolution STED microscopy with scanning fluorescence correlation spectroscopy (scanning STED-FCS, sSTED-FCS) to characterize the spatial and temporal heterogeneity of lipid interactions. sSTED-FCS reveals transient molecular interaction hotspots for a fluorescent sphingolipid analogue. The interaction sites are smaller than 80 nm in diameter and lipids are transiently trapped for several milliseconds in these areas. In comparison, newly developed fluorescent phospholipid and cholesterol analogues with improved phase-partitioning properties show more homogenous diffusion, independent of the preference for liquid-ordered or disordered membrane environments. Our results do not support the presence of nanodomains based on lipid-phase separation in the basal membrane of our cultured nonstimulated cells, and show that alternative interactions are responsible for the strong local trapping of our sphingolipid analogue.

  7. Application of a multi-pass absorption cell for measurement of sputtered tungsten atoms' density

    International Nuclear Information System (INIS)

    A dedicated gas discharge tube equipped with a hollow cathode made of tungsten is setup for sputtering of W atoms. A multi-pass White type absorption cell is designed to increase the sensitivity of the absorption method. The optical system consists of three externally mounted aluminium-coated spherical mirrors with 70 cm radius of curvature. Measurements of the cell relative transmittance in the UV and visible spectral regions are carried out. Time-resolved measurements of sputtered ground-state tungsten atoms' density in 2-pass configuration, as well as assessment of the diffusion coefficient of these atoms in argon at 350 K temperature are made.

  8. Defects influence on short circuit current density in p-i-n silicon solar cell

    International Nuclear Information System (INIS)

    The admittance analysis method has been used to calculate the collection efficiency and the short circuit current density in a-Si:H p-i-n solar cell, as a function of the thickness of i-layer. Its is evident that the results of the short circuit current can be used to determine the optimal thickness of the i-layer of a cell, and it will be more accurate in comparison with the previous studies using a constant generation rate or an empirical exponential function for the generation of charge carriers throughout the i-layer

  9. Estimation of localized current anomalies in polymer electrolyte fuel cells from magnetic flux density measurements

    Science.gov (United States)

    Nara, Takaaki; Koike, Masanori; Ando, Shigeru; Gotoh, Yuji; Izumi, Masaaki

    2016-05-01

    In this paper, we propose novel inversion methods to estimate defects or localized current anomalies in membrane electrode assemblies (MEAs) in polymer electrolyte fuel cells (PEFCs). One method is an imaging approach with L1-norm regularization that is suitable for estimation of focal anomalies compared to Tikhonov regularization. The second is a complex analysis based method in which multiple pointwise current anomalies can be identified directly and algebraically from the measured magnetic flux density.

  10. Bile Acids Reduce Endocytosis of High-Density Lipoprotein (HDL) in HepG2 Cells

    OpenAIRE

    Clemens Röhrl; Karin Eigner; Stefanie Fruhwürth; Herbert Stangl

    2014-01-01

    High-density lipoprotein (HDL) transports lipids to hepatic cells and the majority of HDL-associated cholesterol is destined for biliary excretion. Cholesterol is excreted into the bile directly or after conversion to bile acids, which are also present in the plasma as they are effectively reabsorbed through the enterohepatic cycle. Here, we provide evidence that bile acids affect HDL endocytosis. Using fluorescent and radiolabeled HDL, we show that HDL endocytosis was reduced in the presence...

  11. High cell density strategy for poly(3-hydroxybutyrate production by Cupriavidus necator

    Directory of Open Access Journals (Sweden)

    J. L. Ienczak

    2011-12-01

    Full Text Available Poly(3-hydroxybutyrate (P(3HB is a carbon and intracellular storage source for different microorganisms and its production can achieve high productivities by means of high cell density cultures. The aim of this study was to propose a high cell density strategy for P(3HB production by Cupriavidus necator. The exponential growth phase demands an accurate control of the oxygen transfer system in the bioreactor, due to maximum specific growth rate (µXr, and, consequently, a maximum specific oxygen uptake rate (QO2, in addition to significant residual biomass (Xr growth in high cell density cultures. In this context, this work investigated the strategy for obtaining high cell density, with the inclusion of a linear growth phase for P(3HB production by C. necator in a fed-batch culture. The linear growth phase was included between the exponential growth phase and the P(3HB production phase as a strategy to reduce the specific growth rate (µXr and specific oxygen uptake rate (QO2, with constant residual biomass growth rate (d(V.Xr/dt = k = constant and linear increase of biomass. Three strategies of culture were performed. The results showed that a high residual biomass concentration (30 gXr.L-1 can be reached by the inclusion of the linear growth strategy and specific growth rates (µXr between 0.08 and 0.05 h-1, at the beginning of the production phase, are necessary to attain a high P(3HB productivity.

  12. The effects of blunt trauma and cataract surgery on corneal endothelial cell density

    OpenAIRE

    Yeniad Baris; Corum Isik; Ozgun Cahit

    2010-01-01

    Purpose: This study was designed to investigate the effects of trauma and cataract surgery on corneal endothelial cell density (ECD) in patients with a traumatic cataract due to blunt trauma without globe laceration. Materials and Methods: In this prospective study, 31 subjects with traumatic cataract (traumatic cataract group) and 30 subjects with a senile cataract (control group) were enrolled. The subjects with traumatic cataract were subdivided into two groups: uncomplicated surgery subg...

  13. Phenotypic heterogeneity in metabolic traits among single cells of a rare bacterial species in its natural environment quantified with a combination of flow cell sorting and NanoSIMS

    Directory of Open Access Journals (Sweden)

    Matthias eZimmermann

    2015-04-01

    Full Text Available Populations of genetically identical microorganisms residing in the same environment can display marked variability in their phenotypic traits; this phenomenon is termed phenotypic heterogeneity. The relevance of such heterogeneity in natural habitats is unknown, because phenotypic characterization of a sufficient number of single cells of the same species in complex microbial communities is technically difficult. We report a procedure that allows to measure phenotypic heterogeneity in bacterial populations from natural environments, and use it to analyze N2 and CO2 fixation of single cells of the green sulfur bacterium Chlorobium phaeobacteroides from the meromictic lake Lago di Cadagno. We incubated lake water with 15N2 and 13CO2 under in situ conditions with and without NH4+. Subsequently, we used flow cell sorting with auto-fluorescence gating based on a pure culture isolate to concentrate C. phaeobacteroides from its natural abundance of 0.2 % to 26.5 % of total bacteria. C. phaeobacteroides cells were identified using catalyzed-reporter deposition fluorescence in situ hybridization (CARD-FISH targeting the 16S rRNA in the sorted population with a species-specific probe. In a last step, we used nanometer-scale secondary-ion mass spectrometry (NanoSIMS to measure the incorporation 15N and 13C stable isotopes in more than 252 cells. We found that C. phaeobacteroides fixes N2 in the absence of NH4+, but not in the presence of NH4+ as has previously been suggested. N2 and CO2 fixation were heterogeneous among cells and positively correlated indicating that N2 and CO2 fixation activity interact and positively facilitate each other in individual cells. However, because CARD-FISH identification cannot detect genetic variability among cells of the same species, we cannot exclude genetic variability as a source for phenotypic heterogeneity in this natural population. Our study demonstrates the technical feasibility of measuring phenotypic

  14. Thermo-Physical Properties of Micro-Cell UO2 Pellets and High Density Composite Pellets for Accident Tolerant Fuel

    International Nuclear Information System (INIS)

    This study presents the design and fabrication of micro-cell UO2 fuel pellets and high-density fuel pellets and also evaluates their out-of-pile performance. Micro-cell UO2 pellets are characterized by enhanced retention capability of their fission products and/or thermal conductivity. High-density pellets are composite pellets consisting of oxide and nitride components and they are expected to offer enhanced uranium density and thermal conductivity. (author)

  15. Cheese whey-induced high-cell-density production of recombinant proteins in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Neubauer Peter

    2003-04-01

    Full Text Available Abstract Background Use of lactose-rich concentrates from dairy processes for the induction of recombinant gene's expression has not received much attention although they are interesting low cost substrates for production of recombinant enzymes. Applicability of dairy waste for induction of recombinant genes in Escherichia coli was studied. Clones expressing Lactobacillus phage muramidase and Lactobacillus alcohol dehydrogenase were used for the experiments. Results Shake flask cultivations in mineral salt medium showed that cheese whey or deproteinised whey induced gene expression as efficiently as IPTG (isopropyl-β-D-thiogalactopyranoside or pure lactose. Addition of yeast extract or proteolytically degraded whey proteins did not improve the recombinant protein yield. In contrast, addition of yeast extract to the well-balanced mineral salt medium decreased the product yield. Feeding with glycerol provided sufficient amount of easily assimilable carbon source during the induction period without preventing lactose intake and induction by lactose. High-cell-density fed-batch cultivations showed that product yields comparable to IPTG-induction can be achieved by feeding bacteria with a mixture of glycerol and concentrated whey permeate during the induction. Conclusion Whey and concentrated whey permeate can be applied as an alternative inducer in recombinant high-cell-density fed-batch fermentations. The yield of the recombinant product was comparable to fermentations induced by IPTG. In low-cell-density shake flask experiments the yield was higher with whey or whey permeate than with IPTG.

  16. A Semianalytical Model Using MODIS Data to Estimate Cell Density of Red Tide Algae (Aureococcus anophagefferens

    Directory of Open Access Journals (Sweden)

    Lingling Jiang

    2016-01-01

    Full Text Available A multiband and a single-band semianalytical model were developed to predict algae cell density distribution. The models were based on cell density (N dependent parameterizations of the spectral backscattering coefficients, bb(λ, obtained from in situ measurements. There was a strong relationship between bb(λ and N, with a minimum regression coefficient of 0.97 at 488 nm and a maximum value of 0.98 at other bands. The cell density calculated by the multiband inversion model was similar to the field measurements of the coastal waters (the average relative error was only 8.9%, but it could not accurately discern the red tide from mixed pixels, and this led to overestimation of the area affected by the red tide. While the single-band inversion model is less precise than the former model in the high chlorophyll water, it could eliminate the impact of the suspended sediments and make more accurate estimates of the red tide area. We concluded that the two models both have advantages and disadvantages; these methods lay the foundation for developing a remote sensing forecasting system for red tides.

  17. Effects of Electromagnetic Stimulation on Cell Density and Neural Markers in Murine Enteric Cell Cultures

    International Nuclear Information System (INIS)

    Availability of adult stem cells from several organs like bone marrow, umbilical cord blood or peripheral blood has become a powerful therapeutic tool for many chronic diseases. Potential of adult stem cells for regeneration extents to other tissues among them the nervous system. However two obstacles should be resolved before such cells could be currently applied in clinical practice: a) slow growth rate and b) ability to form enough dense colonies in order to populate a specific injury or cellular deficiency. Many approaches have been explored as genetic differentiation programs, growth factors, and supplemented culture media, among others. Electromagnetic field stimulation of differentiation, proliferation, migration, and particularly on neurogenesis is little known. Since the biological effects of ELF-EMF are well documented, we hypothesize ELF-EMF could affect growth and maturation of stem cells derived of enteric tissue

  18. Effects of Electromagnetic Stimulation on Cell Density and Neural Markers in Murine Enteric Cell Cultures

    Science.gov (United States)

    Carreón-Rodríguez, A.; Belkind-Gerson, J.; Serrano-Luna, G.; Cañedo-Dorantes, L.

    2008-08-01

    Availability of adult stem cells from several organs like bone marrow, umbilical cord blood or peripheral blood has become a powerful therapeutic tool for many chronic diseases. Potential of adult stem cells for regeneration extents to other tissues among them the nervous system. However two obstacles should be resolved before such cells could be currently applied in clinical practice: a) slow growth rate and b) ability to form enough dense colonies in order to populate a specific injury or cellular deficiency. Many approaches have been explored as genetic differentiation programs, growth factors, and supplemented culture media, among others. Electromagnetic field stimulation of differentiation, proliferation, migration, and particularly on neurogenesis is little known. Since the biological effects of ELF-EMF are well documented, we hypothesize ELF-EMF could affect growth and maturation of stem cells derived of enteric tissue.

  19. Mathematical models of tumor heterogeneity and drug resistance

    Science.gov (United States)

    Greene, James

    In this dissertation we develop mathematical models of tumor heterogeneity and drug resistance in cancer chemotherapy. Resistance to chemotherapy is one of the major causes of the failure of cancer treatment. Furthermore, recent experimental evidence suggests that drug resistance is a complex biological phenomena, with many influences that interact nonlinearly. Here we study the influence of such heterogeneity on treatment outcomes, both in general frameworks and under specific mechanisms. We begin by developing a mathematical framework for describing multi-drug resistance to cancer. Heterogeneity is reflected by a continuous parameter, which can either describe a single resistance mechanism (such as the expression of P-gp in the cellular membrane) or can account for the cumulative effect of several mechanisms and factors. The model is written as a system of integro-differential equations, structured by the continuous "trait," and includes density effects as well as mutations. We study the limiting behavior of the model, both analytically and numerically, and apply it to study treatment protocols. We next study a specific mechanism of tumor heterogeneity and its influence on cell growth: the cell-cycle. We derive two novel mathematical models, a stochastic agent-based model and an integro-differential equation model, each of which describes the growth of cancer cells as a dynamic transition between proliferative and quiescent states. By examining the role all parameters play in the evolution of intrinsic tumor heterogeneity, and the sensitivity of the population growth to parameter values, we show that the cell-cycle length has the most significant effect on the growth dynamics. In addition, we demonstrate that the agent-based model can be approximated well by the more computationally efficient integro-differential equations, when the number of cells is large. The model is closely tied to experimental data of cell growth, and includes a novel implementation of

  20. Information in a Network of Neuronal Cells: Effect of Cell Density and Short-Term Depression

    OpenAIRE

    Onesto, Valentina; Cosentino, Carlo; Di Fabrizio, Enzo; Cesarelli, Mario; Amato, Francesco; Gentile, Francesco

    2016-01-01

    Neurons are specialized, electrically excitable cells which use electrical to chemical signals to transmit and elaborate information. Understanding how the cooperation of a great many of neurons in a grid may modify and perhaps improve the information quality, in contrast to few neurons in isolation, is critical for the rational design of cell-materials interfaces for applications in regenerative medicine, tissue engineering, and personalized lab-on-a-chips. In the present paper, we couple an...

  1. Current Density Distribution Mapping in PEM Fuel Cells as An Instrument for Operational Measurements

    Directory of Open Access Journals (Sweden)

    Martin Geske

    2010-04-01

    Full Text Available A newly developed measurement system for current density distribution mapping has enabled a new approach for operational measurements in proton exchange membrane fuel cells (PEMFC. Taking into account previously constructed measurement systems, a method based on a multi layer printed circuit board was chosen for the development of the new system. This type of system consists of a sensor, a special electronic device and the control and visualization PC. For the acquisition of the current density distribution values, a sensor device was designed and installed within a multilayer printed circuit board with integrated shunt resistors. Varying shunt values can be taken into consideration with a newly developed and evaluated calibration method. The sensor device was integrated in a PEM fuel cell stack to prove the functionality of the whole measurement system. A software application was implemented to visualize and save the measurement values. Its functionality was verified by operational measurements within a PEMFC system. Measurement accuracy and possible negative reactions of the sensor device during PEMFC operation are discussed in detail in this paper. The developed system enables operational measurements for different operating phases of PEM fuel cells. Additionally, this can be seen as a basis for new opportunities of optimization for fuel cell design and operation modes.

  2. Changes in small intestinal chromogranin A-immunoreactive cell densities in patients with irritable bowel syndrome after receiving dietary guidance

    OpenAIRE

    Mazzawi, Tarek; El-Salhy, Magdy

    2016-01-01

    Chromogranin A (CgA) is a common marker for enteroendocrine cells in the gut, and CgA-immunoreactive cell densities are abnormal in patients with irritable bowel syndrome (IBS). The majority of patients with IBS report that their symptoms develop after consuming certain foodstuffs. In the present study, we investigated the effects of dietary guidance on the total enteroendocrine cell densities in the small intestine, as detected by CgA. A total of 14 patients with IBS underwent a gastroscopy ...

  3. Differential analysis of the inactivation of yeast cells induced by irradiation with various ionization densities

    International Nuclear Information System (INIS)

    A quantitative investigation is presented on the radiation-induced inactivation of yeast cells in the first generations as a function of dose, repair, and various ionization densities. The study has been made to solve two main questions, i.e.: How do these cells reproduce, and how do they look like at the end of the investigation. Finding the answer to these questions, it was hoped, would lead to a description of survival in the colony test by defining the final fate of the cells which represent the stationary end state. The experiments were to clarify to what extent the dose-response curve yields only relatively general information on radiation-induced damage, or what kind of damage is mainly and best described. This supplementary information will help to improve the interpretation of many experiments having been made with this strain. (orig./MG)

  4. Noninvasive prenatal diagnosis. Use of density gradient centrifugation, magnetically activated cell sorting and in situ hybridization

    DEFF Research Database (Denmark)

    Campagnoli, C; Multhaupt, H A; Ludomirski, A;

    1997-01-01

    centrifugation and dual antibody labeling methods. The protocol was designed to compare the efficacy of antitransferrin receptor (CD71)/antiglycophorin A (GPA) antibodies with antithrom-bospondin receptor (CD36)/anti-GPA antibodies in identifying nucleated erythrocytes in maternal blood. Cytospin preparations...... of the isolated cells were subjected to in situ hybridization with specific DNA probes for the Y chromosome and chromosome 21 to confirm the fetal origin. RESULTS: After MiniMACS the enrichment factors for the CD71/GPA- and CD36/GPA-positive cells from maternal blood were similar, and the percentages of fetal...... cells recovered did not differ. Seven of seven male pregnancies were correctly identified. One case of trisomy 21 was detected. CONCLUSION: The in situ hybridization analysis of fetal nucleated erythrocytes isolated from maternal blood using single density gradient centrifugation, anti-CD71/anti-GPA...

  5. Modeling Approaches for Describing Microbial Population Heterogeneity

    OpenAIRE

    Lencastre Fernandes, Rita; Gernaey, Krist; Jensen, Anker Degn; Nopens, Ingmar

    2013-01-01

    Although microbial populations are typically described by averaged properties, individual cells present a certain degree of variability. Indeed, initially clonal microbial populations develop into heterogeneous populations, even when growing in a homogeneous environment. A heterogeneous microbial population consists of cells in different states, and it implies a heterogeneous distribution of activities (e.g. respiration, product yield), including different responses to extracellular stimuli. ...

  6. ´Sub-atomic´ resolution of non-contact atomic force microscope images induced by a heterogeneous tip structure: a density functional theory study

    Czech Academy of Sciences Publication Activity Database

    Campbellová, A.; Ondráček, Martin; Pou, P.; Pérez, R.; Klapetek, P.; Jelínek, Pavel

    2011-01-01

    Roč. 22, č. 29 (2011), 295710/1-295710/7. ISSN 0957-4484 R&D Projects: GA AV ČR IAA100100905; GA ČR GAP204/10/0952; GA ČR(CZ) GPP204/11/P578 Grant ostatní: AVČR(CZ) M100100904 Institutional research plan: CEZ:AV0Z10100521 Keywords : density functional theory * atomic force microscope * semiconductor surface * sub- atomic resolution Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.979, year: 2011 http://iopscience.iop.org/0957-4484/22/29/295710

  7. Use of Phytone Peptone to Optimize Growth and Cell Density of Lactobacillus reuteri

    Directory of Open Access Journals (Sweden)

    Olabiyi A. Atilola

    2015-08-01

    Full Text Available The objective of this study was to determine the use of phytone peptone to optimize the growth and cell density of Lactobacillus reuteri. Four strains of L. reuteri (DSM 20016, SD 2112, CF 2-7F, and MF 2-3, were used in this study. An overnight culture of individual strains was inoculated into fresh basal media with various protein sources (peptone, tryptone, proteose peptone #3, phytone peptone, tryptic soy broth, yeast extract, and beef extract. Samples were then mixed well and incubated at 37 °C for 15 h. Bacterial growth was monitored by measuring turbidity (optical density 610 nm at different time intervals during the incubation period. At the end of incubation, samples were plated on de-Man Rogosa Sharpe (MRS agar to determine the bacterial population. Our results showed that phytone peptone promoted the growth of L. reuteri (p < 0.05 by 1.4 log CFU/mL on average compared to the control samples. Therefore, phytone peptone could be included in laboratory media to enhance growth and increase the cell density of L. reuteri.

  8. High-Energy-Density, Low-Temperature Li/CFx Primary Cells

    Science.gov (United States)

    Whitacre, Jay; Bugga, Ratnakumar; Smart, Marshall; Prakash, G.; Yazami, Rachid

    2007-01-01

    High-energy-density primary (nonrechargeable) electrochemical cells capable of relatively high discharge currents at temperatures as low as -40 C have been developed through modification of the chemistry of commercial Li/CFx cells and batteries. The commercial Li/CFx units are not suitable for high-current and low-temperature applications because they are current limited and their maximum discharge rates decrease with decreasing temperature. The term "Li/CFx" refers to an anode made of lithium and a cathode made of a fluorinated carbonaceous material (typically graphite). In commercial cells, x typically ranges from 1.05 to 1.1. This cell composition makes it possible to attain specific energies up to 800 Wh/kg, but in order to prevent cell polarization and the consequent large loss of cell capacity, it is typically necessary to keep discharge currents below C/50 (where C is numerically equal to the current that, flowing during a charge or discharge time of one hour, would integrate to the nominal charge or discharge capacity of a cell). This limitation has been attributed to the low electronic conductivity of CFx for x approx. 1. To some extent, the limitation might be overcome by making cathodes thinner, and some battery manufacturers have obtained promising results using thin cathode structures in spiral configurations. The present approach includes not only making cathodes relatively thin [.2 mils (.0.051 mm)] but also using sub-fluorinated CFx cathode materials (x 1. It was known from recent prior research that cells containing sub-fluorinated CFx cathodes (x between 0.33 and 0.66) are capable of retaining substantial portions of their nominal low-current specific energies when discharged at rates as high as 5C at room temperature. However, until experimental cells were fabricated following the present approach and tested, it was not known whether or to what extent low-temperature performance would be improved.

  9. Bidirectional flux of cholesterol between cells and lipoproteins. Effects of phospholipid depletion of high density lipoprotein

    International Nuclear Information System (INIS)

    The bidirectional surface transfer of free cholesterol (FC) between Fu5AH rat hepatoma cells and human high density lipoprotein (HDL) was studied. Cells and HDL were prelabeled with [4-14C]FC and [7-3H]FC, respectively. Influx and efflux of FC were measured simultaneously from the appearance of 3H counts in cells and 14C counts in medium. Results were analyzed by a computerized procedure which fitted sets of kinetic data to a model assuming that cell and HDL FC populations each formed a single homogeneous pool and that together the pools formed a closed system. This analysis yielded values for the first-order rate constants of FC influx and efflux (ki and ke), from which influx and efflux of FC mass (Fi and Fe) could be calculated. With normal HDL, the uptake and release of FC tracers conformed well to the above-described model; Fi and Fe were approximately equal, suggesting an exchange of FC between cells and HDL. HDL was depleted of phospholipid (PL) by treatment with either phospholipase A2 or heparin-releasable rat hepatic lipase, followed by incubation with bovine serum albumin. PL depletion of HDL had little or no effect on ki, but reduced ke, indicating that PL-deficient HDL is a relatively poor acceptor of cell cholesterol. The reduction in ke resulted in initial Fi greater than Fe and, thus, in net uptake of FC by the cells. This result explained previous results demonstrating net uptake of FC from PL-depleted HDL. In the presence of an inhibitor of acyl coenzyme A:cholesterol acyltransferase, the steady state distribution of FC mass between cells and HDL was accurately predicted by the ratio of rate constants for FC flux. This result provided additional validation for describing FC flux in terms of first-order rate constants and homogeneous cell and HDL FC pools

  10. Heterogeneity in Studies of Mesenchymal Stromal Cells to Treat or Prevent Graft-versus-Host Disease: A Scoping Review of the Evidence.

    Science.gov (United States)

    Rizk, Mina; Monaghan, Madeline; Shorr, Risa; Kekre, Natasha; Bredeson, Christopher N; Allan, David S

    2016-08-01

    Effective treatments are lacking for the treatment of steroid-refractory graft-versus-host disease (GVHD), a major cause of morbidity and mortality after allogeneic hematopoietic cell transplantation. Mesenchymal stromal cells (MSCs) have demonstrated promise but there is uncertainty regarding their clinical effectiveness. A systematic scoping review of the literature was performed to characterize the heterogeneity of published studies and identify opportunities for standardization. Thirty studies were identified, including 19 studies (507 patients) addressing the treatment of acute or chronic GVHD and 11 prevention studies (277 patients). Significant heterogeneity was observed in the age and diagnoses of study subjects, intensity and specifics of the conditioning regimens, degree of HLA matching, and source of hematopoietic cells. MSCs were derived from bone marrow (83% of studies), cord blood (13%), or adipose tissue (3%) and were cryopreserved from third-party allogeneic donors in the majority of studies (91% of prevention studies and 63% of treatment studies). Culture conditions and media supplements were highly variable and characterization of MSCs did not conform to all International Society for Cellular Therapy criteria in any study. MSCs were harvested from cell culture at passage 1 to 7 and the dosage of MSCs ranged from 0.3 to 10 × 10(6)/kg, using varying schedules of administration. Treatment response criteria were not standardized and effectiveness in controlled treatment studies (5 studies) was unconvincing. Details of actively recruiting trials suggest heterogeneity still persists with only 53% of registered trials describing the use of standard GVHD response criteria and few detailing methods of MSC manufacturing. Future studies will need to make substantial coordinated efforts to reduce study heterogeneity and clarify the role of MSCs in GVHD. PMID:27130504

  11. LoFreq: a sequence-quality aware, ultra-sensitive variant caller for uncovering cell-population heterogeneity from high-throughput sequencing datasets

    OpenAIRE

    Wilm, Andreas; Aw, Pauline Poh Kim; Bertrand, Denis; Yeo, Grace Hui Ting; Ong, Swee Hoe; Wong, Chang Hua; Khor, Chiea Chuen; Petric, Rosemary; Hibberd, Martin Lloyd; Nagarajan, Niranjan

    2012-01-01

    The study of cell-population heterogeneity in a range of biological systems, from viruses to bacterial isolates to tumor samples, has been transformed by recent advances in sequencing throughput. While the high-coverage afforded can be used, in principle, to identify very rare variants in a population, existing ad hoc approaches frequently fail to distinguish true variants from sequencing errors. We report a method (LoFreq) that models sequencing run-specific error rates to accurately call va...

  12. On modifying the condition for the local current density decoupling in fuel cell stacks for moderate perturbations

    International Nuclear Information System (INIS)

    Two adjacent cells in a fuel cell stack are said to be decoupled when they do not affect each other's local current density distribution. This paper proposes a condition for local current density decoupling between two adjacent cells with arbitrary degree of perturbations. The proposed condition in the form of a bound comprising some measure of the perturbation on a dimensionless number comprising the design, operating conditions, and material properties of the bipolar plate is correlated with the current redistribution between cells and verified with a non-isothermal proton exchange membrane fuel cell stack model

  13. Distribution of the Current Density in Electrolyte of the Pem Fuel Cell

    Directory of Open Access Journals (Sweden)

    Eugeniusz Kurgan

    2004-01-01

    Full Text Available In this paper water management in proton exchange membrane (PEM fuel cell is considered. Firt mass convervation law for water is applied. Next proton transport is described by the Nernst-Planck equation and liqid water convection velocity is eliminated by the Schlogl equation. Electro-osmotic drag coefficient is related to hydrogen index and experimentally determined swelling coefficient. Three partial differential equations for molar water concentration Cw, electric potential ϕ and water pressure Pw are formulated. Current density vector i is derived from proton flux expression. These equations together with adequate boundary conditions were solved using finite element method. The distribution of electric potential and current density in function of geometrical parametres is investigated. At the end some illustrative example is given.

  14. Vertically aligned carbon nanotube electrodes for high current density operating proton exchange membrane fuel cells

    Science.gov (United States)

    Murata, Shigeaki; Imanishi, Masahiro; Hasegawa, Shigeki; Namba, Ryoichi

    2014-05-01

    We successfully developed cathode electrodes for polymer electrolyte membrane fuel cells (PEMFC) that enable operation at high current densities by incorporating vertically aligned carbon nanotubes (CNTs) as the catalyst support; additionally, we prepared 236 cm2 membrane electrodes assemblies (MEAs) for vehicular use. The electrode structure improved the mass transport of reactants, i.e. oxygen, proton, electron and water, in systems performing at a 2.6 A cm-2 current density and 0.6 V with extremely low platinum (Pt) loading at the cathode (0.1 mg cm-2). The improved mass transport caused the 70 mV dec-1 Tafel slope to continue up to 1.0 A cm-2. The mass transport was improved because the pores were continuous, the catalyst support materials did not agglomerate and the catalyst layer made good electrical contact with the microporous layer. Utilizing wavy coil-shaped CNTs was also crucial. These CNTs displayed anti-agglomerative characteristics during the wet manufacturing process and maintained a continuous pore structure framing the layered catalyst structure. Because the CNTs had elastic characteristics, they might fill the space between catalyst and microporous layers to prevent flooding. However, the compressed CNTs in the cells were no longer vertically aligned. Therefore, vertically aligning the nanotubes was important during the MEA manufacturing process but was irrelevant for cell performance.

  15. Dynamic heterogeneity of DNA methylation and hydroxymethylation in embryonic stem cell populations captured by single-cell 3D high-content analysis

    Energy Technology Data Exchange (ETDEWEB)

    Tajbakhsh, Jian, E-mail: tajbakhshj@cshs.org [Chromatin Biology Laboratory, Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, CA 90048 (United States); Translational Cytomics Group, Cedars-Sinai Medical Center, Los Angeles, CA 90048 (United States); Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048 (United States); Stefanovski, Darko [Translational Cytomics Group, Cedars-Sinai Medical Center, Los Angeles, CA 90048 (United States); Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048 (United States); Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19348 (United States); Tang, George [Chromatin Biology Laboratory, Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, CA 90048 (United States); Translational Cytomics Group, Cedars-Sinai Medical Center, Los Angeles, CA 90048 (United States); Wawrowsky, Kolja [Translational Cytomics Group, Cedars-Sinai Medical Center, Los Angeles, CA 90048 (United States); Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048 (United States); Liu, Naiyou; Fair, Jeffrey H. [Department of Surgery and UF Health Comprehensive Transplant Center, University of Florida College of Medicine, Gainesville, FL 32608 (United States)

    2015-03-15

    Cell-surface markers and transcription factors are being used in the assessment of stem cell fate and therapeutic safety, but display significant variability in stem cell cultures. We assessed nuclear patterns of 5-hydroxymethylcytosine (5hmC, associated with pluripotency), a second important epigenetic mark, and its combination with 5-methylcytosine (5mC, associated with differentiation), also in comparison to more established markers of pluripotency (Oct-4) and endodermal differentiation (FoxA2, Sox17) in mouse embryonic stem cells (mESC) over a 10-day differentiation course in vitro: by means of confocal and super-resolution imaging together with 3D high-content analysis, an essential tool in single-cell screening. In summary: 1) We did not measure any significant correlation of putative markers with global 5mC or 5hmC. 2) While average Oct-4 levels stagnated on a cell-population base (0.015 lnIU/day), Sox17 and FoxA2 increased 22-fold and 3-fold faster, respectively (Sox17: 0.343 lnIU/day; FoxA2: 0.046 lnIU/day). In comparison, global DNA methylation levels increased 4-fold faster (0.068 lnIU/day), and global hydroxymethylation declined at 0.046 lnIU/day, both with a better explanation of the temporal profile. 3) This progression was concomitant with the occurrence of distinct nuclear codistribution patterns that represented a heterogeneous spectrum of states in differentiation; converging to three major coexisting 5mC/5hmC phenotypes by day 10: 5hmC{sup +}/5mC{sup −}, 5hmC{sup +}/5mC{sup +}, and 5hmC{sup −}/5mC{sup +} cells. 4) Using optical nanoscopy we could delineate the respective topologies of 5mC/5hmC colocalization in subregions of nuclear DNA: in the majority of 5hmC{sup +}/5mC{sup +} cells 5hmC and 5mC predominantly occupied mutually exclusive territories resembling euchromatic and heterochromatic regions, respectively. Simultaneously, in a smaller subset of cells we observed a tighter colocalization of the two cytosine variants, presumably

  16. Dynamic heterogeneity of DNA methylation and hydroxymethylation in embryonic stem cell populations captured by single-cell 3D high-content analysis

    International Nuclear Information System (INIS)

    Cell-surface markers and transcription factors are being used in the assessment of stem cell fate and therapeutic safety, but display significant variability in stem cell cultures. We assessed nuclear patterns of 5-hydroxymethylcytosine (5hmC, associated with pluripotency), a second important epigenetic mark, and its combination with 5-methylcytosine (5mC, associated with differentiation), also in comparison to more established markers of pluripotency (Oct-4) and endodermal differentiation (FoxA2, Sox17) in mouse embryonic stem cells (mESC) over a 10-day differentiation course in vitro: by means of confocal and super-resolution imaging together with 3D high-content analysis, an essential tool in single-cell screening. In summary: 1) We did not measure any significant correlation of putative markers with global 5mC or 5hmC. 2) While average Oct-4 levels stagnated on a cell-population base (0.015 lnIU/day), Sox17 and FoxA2 increased 22-fold and 3-fold faster, respectively (Sox17: 0.343 lnIU/day; FoxA2: 0.046 lnIU/day). In comparison, global DNA methylation levels increased 4-fold faster (0.068 lnIU/day), and global hydroxymethylation declined at 0.046 lnIU/day, both with a better explanation of the temporal profile. 3) This progression was concomitant with the occurrence of distinct nuclear codistribution patterns that represented a heterogeneous spectrum of states in differentiation; converging to three major coexisting 5mC/5hmC phenotypes by day 10: 5hmC+/5mC−, 5hmC+/5mC+, and 5hmC−/5mC+ cells. 4) Using optical nanoscopy we could delineate the respective topologies of 5mC/5hmC colocalization in subregions of nuclear DNA: in the majority of 5hmC+/5mC+ cells 5hmC and 5mC predominantly occupied mutually exclusive territories resembling euchromatic and heterochromatic regions, respectively. Simultaneously, in a smaller subset of cells we observed a tighter colocalization of the two cytosine variants, presumably delineating chromatin domains in remodeling. We

  17. 'Sub-atomic' resolution of non-contact atomic force microscope images induced by a heterogeneous tip structure: a density functional theory study

    Energy Technology Data Exchange (ETDEWEB)

    Campbellova, Anna; Klapetek, Petr [Czech Metrology Institute, OkruznI 31, 638 00, Brno (Czech Republic); Ondracek, Martin; JelInek, Pavel [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 162 00 Prague (Czech Republic); Pou, Pablo; Perez, Ruben, E-mail: jelinekp@fzu.cz [Departamento de Fisica Teorica de la Materia Condensada, Universidad Autonoma de Madrid, 28049 Madrid (Spain)

    2011-07-22

    A Si adatom on a Si(111)-(7 x 7) reconstructed surface is a typical atomic feature that can rather easily be imaged by a non-contact atomic force microscope (nc-AFM) and can be thus used to test the atomic resolution of the microscope. Based on our first principles density functional theory (DFT) calculations, we demonstrate that the structure of the termination of the AFM tip plays a decisive role in determining the appearance of the adatom image. We show how the AFM image changes depending on the tip-surface distance and the composition of the atomic apex at the end of the tip. We also demonstrate that contaminated tips may give rise to image patterns displaying so-called 'sub-atomic' features even in the attractive force regime.

  18. Bile acids reduce endocytosis of high-density lipoprotein (HDL in HepG2 cells.

    Directory of Open Access Journals (Sweden)

    Clemens Röhrl

    Full Text Available High-density lipoprotein (HDL transports lipids to hepatic cells and the majority of HDL-associated cholesterol is destined for biliary excretion. Cholesterol is excreted into the bile directly or after conversion to bile acids, which are also present in the plasma as they are effectively reabsorbed through the enterohepatic cycle. Here, we provide evidence that bile acids affect HDL endocytosis. Using fluorescent and radiolabeled HDL, we show that HDL endocytosis was reduced in the presence of high concentrations of taurocholate, a natural non-cell-permeable bile acid, in human hepatic HepG2 and HuH7 cells. In contrast, selective cholesteryl-ester (CE uptake was increased. Taurocholate exerted these effects extracellularly and independently of HDL modification, cell membrane perturbation or blocking of endocytic trafficking. Instead, this reduction of endocytosis and increase in selective uptake was dependent on SR-BI. In addition, cell-permeable bile acids reduced HDL endocytosis by farnesoid X receptor (FXR activation: chenodeoxycholate and the non-steroidal FXR agonist GW4064 reduced HDL endocytosis, whereas selective CE uptake was unaltered. Reduced HDL endocytosis by FXR activation was independent of SR-BI and was likely mediated by impaired expression of the scavenger receptor cluster of differentiation 36 (CD36. Taken together we have shown that bile acids reduce HDL endocytosis by transcriptional and non-transcriptional mechanisms. Further, we suggest that HDL endocytosis and selective lipid uptake are not necessarily tightly linked to each other.

  19. Ultra-deep T cell receptor sequencing reveals the complexity and intratumour heterogeneity of T cell clones in renal cell carcinomas

    OpenAIRE

    Gerlinger, Marco; Quezada, Sergio A; Peggs, Karl S.; Furness, Andrew JS; Fisher, Rosalie; Marafioti, Teresa; Shende, Vishvesh H.; McGranahan, Nicholas; Rowan, Andrew J.; Hazell, Steven; Hamm, David; Robins, Harlan S; Pickering, Lisa; Gore, Martin; Nicol, David L.

    2013-01-01

    The recognition of cancer cells by T cells can impact upon prognosis and be exploited for immunotherapeutic approaches. This recognition depends on the specific interaction between antigens displayed on the surface of cancer cells and the T cell receptor (TCR), which is generated by somatic rearrangements of TCR α- and β-chains (TCRb). Our aim was to assess whether ultra-deep sequencing of the rearranged TCRb in DNA extracted from unfractionated clear cell renal cell carcinoma (ccRCC) samples...

  20. Increased density of tolerogenic dendritic cells in the small bowel mucosa of celiac patients

    Science.gov (United States)

    Vorobjova, Tamara; Uibo, Oivi; Heilman, Kaire; Uibo, Raivo

    2015-01-01

    AIM: To investigate the densities of dendritic cells (DCs) and FOXP3+ regulatory T cells (Tregs) and their interrelations in the small bowel mucosa in untreated celiac disease (CD) patients with and without type 1 diabetes (T1D). METHODS: Seventy-four patients (45 female, 29 male, mean age 11.1 ± 6.8 years) who underwent small bowel biopsy were studied. CD without T1D was diagnosed in 18 patients, and CD with T1D was diagnosed in 15 patients. Normal small bowel mucosa was found in two T1D patients. Thirty-nine patients (mean age 12.8 ± 4.9 years) with other diagnoses (functional dyspepsia, duodenal ulcer, erosive gastritis, etc.) formed the control group. All CD patients had partial or subtotal villous atrophy according to the Marsh classification: Marsh grade IIIa in 9, grade IIIb in 21 and grade IIIc in 3 cases. Thirty-nine patients without CD and 2 with T1D had normal small bowel mucosa (Marsh grade 0). The densities of CD11c+, IDO+, CD103+, Langerin (CD207+) DCs and FOXP3+ Tregs were investigated by immunohistochemistry (on paraffin-embedded specimens) and immunofluorescence (on cryostat sections) methods using a combination of mono- and double-staining. Sixty-six serum samples were tested for IgA-tissue transglutaminase (tTG) using a fully automated EliA™ Celikey® IgA assay (Pharmacia Diagnostics, Freiburg, Germany). RESULTS: The density of CD11c+ DCs was significantly increased in CD patients compared with patients with normal mucosa (21.67 ± 2.49 vs 13.58 ± 1.51, P = 0.007). The numbers of FOXP3+ cells were significantly higher in CD patients (10.66 ± 1.50 vs 1.92 ± 0.37, P = 0.0002) and in patients with CD and coexisting T1D (8.11 ± 1.64 vs 1.92 ± 0.37, P = 0.002) compared with patients with normal mucosa. The density of FOXP3+ cells significantly correlated with the histological grade of atrophic changes in the small bowel mucosa according to the March classification (r = 0.62; P < 0.0001) and with levels of IgA antibody (r = 0.55; P < 0

  1. A divide-and-conquer strategy in tumor sampling enhances detection of intratumor heterogeneity in routine pathology: A modeling approach in clear cell renal cell carcinoma

    Science.gov (United States)

    Lopez, José I.; Cortes, Jesús M.

    2016-01-01

    Intratumor heterogeneity (ITH) is an inherent process in cancer development which follows for most of the cases a branched pattern of evolution, with different cell clones evolving independently in space and time across different areas of the same tumor. The determination of ITH (in both spatial and temporal domains) is nowadays critical to enhance patient treatment and prognosis. Clear cell renal cell carcinoma (CCRCC) provides a good example of ITH. Sometimes the tumor is too big to be totally analyzed for ITH detection and pathologists decide which parts must be sampled for the analysis. For such a purpose, pathologists follow internationally accepted protocols. In light of the latest findings, however, current sampling protocols seem to be insufficient for detecting ITH with significant reliability. The arrival of new targeted therapies, some of them providing promising alternatives to improve patient survival, pushes the pathologist to obtain a truly representative sampling of tumor diversity in routine practice. How large this sampling must be and how this must be performed are unanswered questions so far.  Here we present a very simple method for tumor sampling that enhances ITH detection without increasing costs. This method follows a divide-and-conquer (DAC) strategy, that is, rather than sampling a small number of large-size tumor-pieces as the routine protocol (RP) advises, we suggest sampling many small-size pieces along the tumor. We performed a computational modeling approach to show that the usefulness of the DAC strategy is twofold: first, we show that DAC outperforms RP with similar laboratory costs, and second, DAC is capable of performing similar to total tumor sampling (TTS) but, very remarkably, at a much lower cost. We thus provide new light to push forward a shift in the paradigm about how pathologists should sample tumors for achieving efficient ITH detection. PMID:27127618

  2. Degradation of Solid Oxide Electrolysis Cells Operated at High Current Densities

    DEFF Research Database (Denmark)

    Tao, Youkun; Ebbesen, Sune Dalgaard; Mogensen, Mogens Bjerg

    2014-01-01

    process and the reaction process at the Ni-YSZ triple-phase boundaries. The performance degradation is mainly ascribed to the microstructural changes in the Ni-YSZ electrode close to the YSZ electrolyte, including percolation loss of Ni and the contact loss of Ni and YSZ electrolyte. The type of the......In this work the durability of solid oxide cells for co-electrolysis of steam and carbon dioxide (45 % H2O + 45 % CO2 + 10 % H2) at high current densities was investigated. The tested cells are Ni-YSZ electrode supported, with a YSZ electrolyte and either a LSM-YSZ or LSCF-CGO oxygen electrode. A...... oxygen electrode showed an influence to the ohmic degradation: the better performing oxygen electrode corresponded to a lower Rs increase. However, the oxygen electrode itself was found to be relative stable both with respect to the electrochemical performance and microstructure....

  3. High short-circuit current density CdTe solar cells using all-electrodeposited semiconductors

    International Nuclear Information System (INIS)

    CdS/CdTe and ZnS/CdTe n–n heterojunction solar cells have been fabricated using all-electrodeposited semiconductors. The best devices show remarkable high short-circuit current densities of 38.5 mAcm−2 and 47.8 mAcm−2, open-circuit voltages of 630 mV and 646 mV and conversion efficiencies of 8.0% and 12.0% respectively. The major strength of these device structures lies in the combination of n–n heterojunction with a large Schottky barrier at the n-CdTe/metal back contact which provides the required band bending for the separation of photo-generated charge carriers. This is in addition to the use of a high quality n-type CdTe absorber layer with high electron mobility. The potential barrier heights estimated for these devices from the current–voltage characteristics exceed 1.09 eV and 1.13 eV for CdS/CdTe and ZnS/CdTe cells respectively. The diode rectification factors of both devices are in excess of four orders of magnitude with reverse saturation current densities of 1.0 × 10−7 Acm−2 and 4.0 × 10−7 Acm−2 respectively. These all-electrodeposited solar cell device structures are currently being studied and developed as an alternative to the well-known p–n junction structures which utilise chemical bath-deposited CdS. The preliminary material growth, device fabrication and assessment results are presented in this paper. - Highlights: • Two-electrode deposition. • High Jsc Schottky barrier solar cells. • CdCl2 + CdF2 treatment

  4. High power-density single-chamber fuel cells operated on methane

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Zongping; Mederos, Jennifer; Chueh, William C.; Haile, Sossina.M. [Materials Science, Chemical Engineering, California Institute of Technology, Pasadena, CA 91125 (United States)

    2006-11-08

    Single-chamber solid oxide fuel cells (SC-SOFCs) incorporating thin-film Sm{sub 0.15}Ce{sub 0.85}O{sub 1.925} (SDC) as the electrolyte, thick Ni+SDC as the (supporting) anode and SDC+BSCF (Ba{sub 0.5}Sr{sub 0.5}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}}) as the cathode were operated in a mixture of methane, oxygen and helium at furnace temperatures of 500-650{sup o}C. Because of the exothermic nature of the oxidation reactions that occur at the anode, the cell temperature was as much as 150{sup o}C greater than the furnace temperature. Overall, the open circuit voltage was only slightly sensitive to temperature and gas composition, varying from {approx}0.70 to {approx}0.78V over the range of conditions explored. In contrast, the power density strongly increased with temperature and broadly peaked at a methane to oxygen ratio of {approx}1:1. At a furnace temperature of 650{sup o}C (cell temperature {approx}790{sup o}C), a peak power density of 760mWcm{sup -2} was attained using a mixed gas with methane, oxygen and helium flow rates of 87, 80 and 320mLmin{sup -1} [STP], respectively. This level of power output is the highest reported in the literature for single chamber fuel cells and reflects the exceptionally high activity of the BSCF cathode for oxygen electro-reduction and its low activity for methane oxidation. (author)

  5. Durability of Low Platinum Fuel Cells Operating at High Power Density

    Energy Technology Data Exchange (ETDEWEB)

    Polevaya, Olga [Nuvera Fuel Cells Inc.; Blanchet, Scott [Nuvera Fuel Cells Inc.; Ahluwalia, Rajesh [Argonne National Lab; Borup, Rod [Los-Alamos National Lab; Mukundan, Rangachary [Los-Alamos National Lab

    2014-03-19

    Understanding and improving the durability of cost-competitive fuel cell stacks is imperative to successful deployment of the technology. Stacks will need to operate well beyond today’s state-of-the-art rated power density with very low platinum loading in order to achieve the cost targets set forth by DOE ($15/kW) and ultimately be competitive with incumbent technologies. An accelerated cost-reduction path presented by Nuvera focused on substantially increasing power density to address non-PGM material costs as well as platinum. The study developed a practical understanding of the degradation mechanisms impacting durability of fuel cells with low platinum loading (≤0.2mg/cm2) operating at high power density (≥1.0W/cm2) and worked out approaches for improving the durability of low-loaded, high-power stack designs. Of specific interest is the impact of combining low platinum loading with high power density operation, as this offers the best chance of achieving long-term cost targets. A design-of-experiments approach was utilized to reveal and quantify the sensitivity of durability-critical material properties to high current density at two levels of platinum loading (the more conventional 0.45 mgPt.cm–1 and the much lower 0.2 mgPt.cm–2) across several cell architectures. We studied the relevance of selected component accelerated stress tests (AST) to fuel cell operation in power producing mode. New stress tests (NST) were designed to investigate the sensitivity to the addition of electrical current on the ASTs, along with combined humidity and load cycles and, eventually, relate to the combined city/highway drive cycle. Changes in the cathode electrochemical surface area (ECSA) and average oxygen partial pressure on the catalyst layer with aging under AST and NST protocols were compared based on the number of completed cycles. Studies showed elevated sensitivity of Pt growth to the potential limits and the initial particle size distribution. The ECSA loss

  6. BDNF over-expression increases olfactory bulb granule cell dendritic spine density in vivo.

    Science.gov (United States)

    McDole, B; Isgor, C; Pare, C; Guthrie, K

    2015-09-24

    Olfactory bulb granule cells (GCs) are axon-less, inhibitory interneurons that regulate the activity of the excitatory output neurons, the mitral and tufted cells, through reciprocal dendrodendritic synapses located on GC spines. These contacts are established in the distal apical dendritic compartment, while GC basal dendrites and more proximal apical segments bear spines that receive glutamatergic inputs from the olfactory cortices. This synaptic connectivity is vital to olfactory circuit function and is remodeled during development, and in response to changes in sensory activity and lifelong GC neurogenesis. Manipulations that alter levels of the neurotrophin brain-derived neurotrophic factor (BDNF) in vivo have significant effects on dendritic spine morphology, maintenance and activity-dependent plasticity for a variety of CNS neurons, yet little is known regarding BDNF effects on bulb GC spine maturation or maintenance. Here we show that, in vivo, sustained bulbar over-expression of BDNF in transgenic mice produces a marked increase in GC spine density that includes an increase in mature spines on their apical dendrites. Morphometric analysis demonstrated that changes in spine density were most notable in the distal and proximal apical domains, indicating that multiple excitatory inputs are potentially modified by BDNF. Our results indicate that increased levels of endogenous BDNF can promote the maturation and/or maintenance of dendritic spines on GCs, suggesting a role for this factor in modulating GC functional connectivity within adult olfactory circuitry. PMID:26211445

  7. The influence of neuronal density and maturation on network activity of hippocampal cell cultures: a methodological study.

    Directory of Open Access Journals (Sweden)

    Emilia Biffi

    Full Text Available It is known that cell density influences the maturation process of in vitro neuronal networks. Neuronal cultures plated with different cell densities differ in number of synapses per neuron and thus in single neuron synaptic transmission, which results in a density-dependent neuronal network activity. Although many authors provided detailed information about the effects of cell density on neuronal culture activity, a dedicated report of density and age influence on neuronal hippocampal culture activity has not yet been reported. Therefore, this work aims at providing reference data to researchers that set up an experimental study on hippocampal neuronal cultures, helping in planning and decoding the experiments. In this work, we analysed the effects of both neuronal density and culture age on functional attributes of maturing hippocampal cultures. We characterized the electrophysiological activity of neuronal cultures seeded at three different cell densities, recording their spontaneous electrical activity over maturation by means of MicroElectrode Arrays (MEAs. We had gather data from 86 independent hippocampal cultures to achieve solid statistic results, considering the high culture-to-culture variability. Network activity was evaluated in terms of simple spiking, burst and network burst features. We observed that electrical descriptors were characterized by a functional peak during maturation, followed by a stable phase (for sparse and medium density cultures or by a decrease phase (for high dense neuronal cultures. Moreover, 900 cells/mm(2 cultures showed characteristics suitable for long lasting experiments (e.g. chronic effect of drug treatments while 1800 cells/mm(2 cultures should be preferred for experiments that require intense electrical activity (e.g. to evaluate the effect of inhibitory molecules. Finally, cell cultures at 3600 cells/mm(2 are more appropriate for experiments in which time saving is relevant (e.g. drug screenings

  8. Site-Specific Prevalence and Cell Densities of Selected Microbes in the Lower Reproductive Tract of Menstruating Tampon Users

    OpenAIRE

    Rachelle Eusebio; Meyer, Sandy J.; Berg, Ronald W; Hochwalt, Anne E

    2002-01-01

    OBJECTIVE: To assess differences in prevalence and cell densities of enterococci, Gram negative enterics (GNEs), yeast and Staphylococcus aureus among four genital sites and to examine whether the presence of organisms at one site affected the presence of organisms at other sites. METHODS: Swab samples from the perineum, below and above the hymen, and the posterior fornix obtained from 52 tampon users on menstrual cycle day 3 were analyzed for site-specific prevalence and cell densities of mi...

  9. High-density lipoprotein is a potential growth factor for adrenocortical cells

    International Nuclear Information System (INIS)

    The entry of cholesterol contained within high-density lipoprotein (HDL) into adrenocortical cells is mediated by a human homologue of SR-BI, CD36, and LIMPII Analogous-1 (CLA-1) and thus augmenting their growth. To address the role of CLA-1, we created a mutant mCLA that lacked the C-terminal tail. HDL CE selective uptake by cells carrying the mCLA-1 receptor was fully active and equivalent to those transfected with full-length CLA-1 (fCLA-1). Expression of mCLA inhibited the proliferation of an adrenocortical cell line and the incorporation of [3H]thymidine into the cells. This effect was sensitive to wortmannin, an inhibitor of phosphoinositide 3-kinase (PI3K). Our transcriptional studies revealed that the inhibitory action of mCLA required the transcriptional factor AP-1 and the effect of HDL on AP-1 activation was also abrogated by wortmannin. These findings raise the possibility that the inhibitors of the effects of HDL may be of therapeutic value for adrenocortical tumor

  10. Enhanced photocurrent density in graphene/Si based solar cell (GSSC) by optimizing active layer thickness

    Energy Technology Data Exchange (ETDEWEB)

    Rosikhin, Ahmad, E-mail: a.rosikhin86@yahoo.co.id; Hidayat, Aulia Fikri; Syuhada, Ibnu; Winata, Toto, E-mail: toto@fi.itb.ac.id [Department of physics, physics of electronic materials research division Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung Jl. Ganesha 10, Bandung 40132, Jawa Barat – Indonesia (Indonesia)

    2015-12-29

    Thickness dependent photocurrent density in active layer of graphene/Si based solar cell has been investigated via analytical – simulation study. This report is a preliminary comparison of experimental and analytical investigation of graphene/Si based solar cell. Graphene sheet was interfaced with Si thin film forming heterojunction solar cell that was treated as a device model for photocurrent generator. Such current can be enhanced by optimizing active layer thickness and involving metal oxide as supporting layer to shift photons absorption. In this case there are two type of devices model with and without TiO{sub 2} in which the silicon thickness varied at 20 – 100 nm. All of them have examined and also compared with each other to obtain an optimum value. From this calculation it found that generated currents almost linear with thickness but there are saturated conditions that no more enhancements will be achieved. Furthermore TiO{sub 2} layer is effectively increases photon absorption but reducing device stability, maximum current is fluctuates enough. This may caused by the disturbance of excitons diffusion and resistivity inside each layer. Finally by controlling active layer thickness, it is quite useful to estimate optimization in order to develop the next solar cell devices.

  11. Enhanced current and power density of micro-scale microbial fuel cells with ultramicroelectrode anodes

    Science.gov (United States)

    Ren, Hao; Rangaswami, Sriram; Lee, Hyung-Sool; Chae, Junseok

    2016-09-01

    We present a micro-scale microbial fuel cell (MFC) with an ultramicroelectrode (UME) anode, with the aim of creating a miniaturized high-current/power-density converter using carbon-neutral and renewable energy sources. Micro-scale MFCs have been studied for more than a decade, yet their current and power densities are still an order of magnitude lower than those of their macro-scale counterparts. In order to enhance the current/power densities, we engineer a concentric ring-shaped UME, with a width of 20 μm, to facilitate the diffusion of ions in the vicinity of the micro-organisms that form biofilm on the UME. The biofilm extends approximately 15 μm from the edge of the UME, suggesting the effective biofilm area increases. Measured current/power densities per the effective area and the original anode area are 7.08  ±  0.01 A m‑2 & 3.09  ±  0.04 W m‑2 and 17.7  ±  0.03 A m‑2 & 7.72  ±  0.09 W m‑2, respectively. This is substantially higher than any prior work in micro-scale MFCs, and very close, or even higher, to that of macro-scale MFCs. A Coulombic efficiency, a measure of how efficiently an MFC harvests electrons from donor substrate, of 70%, and an energy conversion efficiency of 17% are marked, highlighting the micro-scale MFC as an attractive alternative within the existing energy conversion portfolio.

  12. RECQL4-deficient cells are hypersensitive to oxidative stress/damage: Insights for osteosarcoma prevalence and heterogeneity in Rothmund-Thomson syndrome

    International Nuclear Information System (INIS)

    Rothmund-Thomson syndrome (RTS) is a heterogeneous disease, associated with increased prevalence of osteosarcoma in very young patients with a mutated RECQL4 gene. In this study, we tested the ability of RECQL4 deficient fibroblasts, derived from a RTS patient to recover from hydrogen peroxide (H2O2)-induced oxidative stress/damage. Immunoperoxidase staining for 8-oxo-deoxyguanosine (8-oxo-dG) formation in RTS and normal human fibroblasts were compared to assess DNA damage. We determined DNA synthesis, cell growth, cell cycle distribution, and viability in RTS and normal human fibroblasts before and after H2O2 treatment. H2O2 induces 8-oxo-dG formation in both RTS and normal fibroblasts. In normal human fibroblasts, RECQL4 was predominantly localized to cytoplasm; nuclear translocation and foci formation occurred in response to oxidant stimulation. After recovery from oxidant exposure, viable RTS fibroblasts showed irreversible growth arrest compared to normal fibroblasts. DNA synthesis decreased significantly in treated RTS cells, with concomitant reduction of cells in the S-phase. These results suggest that enhanced oxidant sensitivity in RECQL4 deficient fibroblasts derived from RTS patients could be attributed to abnormal DNA metabolism and proliferation failure. The ramifications of these findings on osteosarcoma prevalence and heterogeneity in RTS are discussed

  13. Cell Density Effects of Frog Skin Bacteria on Their Capacity to Inhibit Growth of the Chytrid Fungus, Batrachochytrium dendrobatidis.

    Science.gov (United States)

    Yasumiba, Kiyomi; Bell, Sara; Alford, Ross

    2016-01-01

    Bacterial symbionts on frog skin can reduce the growth of the chytrid fungus Batrachochytrium dendrobatidis (Bd) through production of inhibitory metabolites. Bacteria can be effective at increasing the resistance of amphibians to chytridiomycosis when added to amphibian skin, and isolates can be screened for production of metabolites that inhibit Bd growth in vitro. However, some bacteria use density-dependent mechanism such as quorum sensing to regulate metabolite production. It is therefore important to consider cell density effects when evaluating bacteria as possible candidates for bioaugmentation. The aim of our study was to evaluate how the density of cutaneous bacteria affects their inhibition of Bd growth in vitro. We sampled cutaneous bacteria isolated from three frog species in the tropical rainforests of northern Queensland, Australia, and selected ten isolates that were inhibitory to Bd in standardised pilot trials. We grew each isolate in liquid culture at a range of initial dilutions, sub-sampled each dilution at a series of times during the first 48 h of growth and measured spectrophotometric absorbance values, cell counts and Bd-inhibitory activity of cell-free supernatants at each time point. The challenge assay results clearly demonstrated that the inhibitory effects of most isolates were density dependent, with relatively low variation among isolates in the minimum cell density needed to inhibit Bd growth. We suggest the use of minimum cell densities and fast-growing candidate isolates to maximise bioaugmentation efforts. PMID:26563320

  14. Automated computation of arbor densities: a step toward identifying neuronal cell types

    Directory of Open Access Journals (Sweden)

    Uygar eSümbül

    2014-11-01

    Full Text Available The shape and position of a neuron convey information regarding its molecular and functional identity. The identification of cell types from structure, a classic method, relies on the time-consuming step of arbor tracing. However, as genetic tools and imaging methods make data-driven approaches to neuronal circuit analysis feasible, the need for automated processing increases. Here, we first establish that mouse retinal ganglion cell types can be as precise about distributing their arbor volumes across the inner plexiform layer as they are about distributing the skeletons of the arbors. Then, we describe an automated approach to computing the spatial distribution of the dendritic arbors, or arbor density, with respect to a global depth coordinate based on this observation. Our method involves three-dimensional reconstruction of neuronal arbors by a supervised machine learning algorithm, post-processing of the enhanced stacks to remove somata and isolate the neuron of interest, and registration of neurons to each other using automatically detected arbors of the starburst amacrine interneurons as fiducial markers. In principle, this method could be generalizable to other structures of the CNS, provided that they allow sparse labeling of the cells and contain a reliable axis of spatial reference.

  15. Impact of Pancreatic Rat Islet Density on Cell Survival during Hypoxia

    Directory of Open Access Journals (Sweden)

    A. Rodriguez-Brotons

    2016-01-01

    Full Text Available In bioartificial pancreases (BP, the number of islets needed to restore normoglycaemia in the diabetic patient is critical. However, the confinement of a high quantity of islets in a limited space may impact islet survival, particularly in regard to the low oxygen partial pressure (PO2 in such environments. The aim of the present study was to evaluate the impact of islet number in a confined space under hypoxia on cell survival. Rat islets were seeded at three different concentrations (150, 300, and 600 Islet Equivalents (IEQ/cm2 and cultured in normal atmospheric pressure (160 mmHg as well as hypoxic conditions (15 mmHg for 24 hours. Cell viability, function, hypoxia-induced changes in gene expression, and cytokine secretion were then assessed. Notably, hypoxia appeared to induce a decrease in viability and increasing islet density exacerbated the observed increase in cellular apoptosis as well as the loss of function. These changes were also associated with an increase in inflammatory gene transcription. Taken together, these data indicate that when a high number of islets are confined to a small space under hypoxia, cell viability and function are significantly impacted. Thus, in order to improve islet survival in this environment during transplantation, oxygenation is of critical importance.

  16. Possible Prognostic and Therapeutic Significance of c-Kit Expression, Mast Cell Count and Microvessel Density in Renal Cell Carcinoma

    Directory of Open Access Journals (Sweden)

    Ilaria Marech

    2014-07-01

    Full Text Available Renal cell carcinoma (RCC is the most frequent renal tumor and its incidence is increasing worldwide. Tumor angiogenesis is known to play a crucial role in the etiopathogenesis of RCC and over the last few years an even deeper knowledge of its contribution in metastatic RCC development has led to the development of numerous molecular targeting agents (such as sunitinib, sorafenib, pazopanib, axitinib, tivozanib, and dovitinib. The above agents are principally directed against vascular endothelial growth factor receptor (VEGFR members and also against c-Kit receptor (c-KitR. The role of c-kitR inhibition on clear cell RCC (ccRCC, the main RCC subtype, is less well established. Whether c-kitR activation through its ligand, stem cell factor (SCF contributes significantly to the effects of tyrosine kinase inhibitors (TKIs treatment remains to be established. It is important to underscore that the c-KitR is expressed on mast cells (MCs and cancer cells. After an examination of the c-KitR/SCF pathway, we review here the principal studies that have evaluated c-Kit expression in RCC. Moreover, we summarize some investigations that have observed the distribution of MCs in primary renal cancer and in adjacent normal tissue with appropriate histological immunohistochemical techniques. We also focus on few studies that have evaluated the correlation between RCC proliferation, MC count and microvessel density (MVD, as hallmarks of tumor angiogenesis. Thus, the aim of this review of the literature is to clarify if c-KitR expression, MC count and MVD could have prognostic significance and the possible predictive therapeutic implications in RCC.

  17. Interleukin 21 therapy increases the density of tumor infiltrating CD8+ T cells and inhibits the growth of syngeneic tumors

    DEFF Research Database (Denmark)

    Søndergaard, Henrik; Frederiksen, Klaus S; Thygesen, Peter; Galsgaard, Elisabeth D; Skak, Kresten; Kristjansen, Paul E G; Odum, Niels; Kragh, Michael

    2007-01-01

    infiltrating T cells. We treated mice bearing established subcutaneous B16 melanomas or RenCa renal cell carcinomas with intraperitoneal (i.p.) or subcutaneous (s.c.) IL-21 protein therapy and subsequently scored the densities of tumor infiltrating CD4(+) and CD8(+) T cells by immunohistochemistry. Whereas.......c. administration, which could account for the apparent increase in anti-tumor activity. Specific depletion of CD8(+) T cells with monoclonal antibodies completely abrogated the anti-tumor activity, whereas NK1.1(+) cell depletion did not affect tumor growth. In accordance, both routes of IL-21 administration...... significantly increased the density of tumor infiltrating CD8(+) T cells in both B16 and RenCa tumors; and in the RenCa model s.c. administration of IL-21 led to a significantly higher density of tumor infiltrating CD8(+) T cells compared to i.p. administration. The densities of CD4(+) T cells were unchanged...

  18. Optimization of high cell density fermentation process for recombinant nitrilase production in E. coli.

    Science.gov (United States)

    Sohoni, Sujata Vijay; Nelapati, Dhanaraj; Sathe, Sneha; Javadekar-Subhedar, Vaishali; Gaikaiwari, Raghavendra P; Wangikar, Pramod P

    2015-01-01

    Nitrilases constitute an important class of biocatalysts for chiral synthesis. This work was undertaken with the aim to optimize nitrilase production in a host that is well-studied for protein production. Process parameters were optimized for high cell density fermentation, in batch and fed-batch modes, of Escherichia coli BL21 (DE3) expressing Pseudomonas fluorescens nitrilase with a T7 promoter based expression system. Effects of different substrates, temperature and isopropyl β-D-1-thiogalactopyranoside (IPTG) induction on nitrilase production were studied. Super optimal broth containing glycerol but without an inducer gave best results in batch mode with 32 °C as the optimal temperature. Use of IPTG led to insoluble protein and lower enzyme activity. Optimized fed-batch strategy resulted in significant improvement in specific activity as well as volumetric productivity of the enzyme. On a volumetric basis, the activity improved 40-fold compared to the unoptimized batch process. PMID:25739996

  19. High-cell-density fermentation for ergosterol production by Saccharomyces cerevisiae.

    Science.gov (United States)

    Shang, Fei; Wen, Shaohong; Wang, Xi; Tan, Tianwei

    2006-01-01

    The direct feedback control of glucose using an on-line ethanol concentration monitor for ergosterol production by high-cell-density fermentation was investigated and the fermentation parameters (e.g., pH, dissolved oxygen, ethanol concentration, oxygen uptake rate, carbon dioxide evolution rate and respiratory quotient) were analyzed. Controlling glucose feeding rate in accordance with ethanol concentration and adjusting pH with ammonia during the fermentation process were effective fed-batch methods for ergosterol production. The fermentation parameters well described the variation of the whole fermentation process. Cultivation in a 5 l fermentor was carried out under the following conditions: culture temperature, 30 degrees C; pH, 5.5; agitation speed, 600 rpm; fermentation time, 60 h; controlling ethanol concentration below 1% and keeping respiratory quotient (RQ) at approximately 1.0. Under these conditions, the yeast dry weight reached 120 g/l and the ergosterol yield reached 1500 mg/l. PMID:16503289

  20. Cell Density Control of Staphylococcal Virulence Mediated by an Octapeptide Pheromone

    Science.gov (United States)

    Ji, Guangyong; Beavis, Ronald C.; Novick, Richard P.

    1995-12-01

    Some bacterial pathogens elaborate and secrete virulence factors in response to environmental signals, others in response to a specific host product, and still others in response to no discernible cue. In this study, we have demonstrated that the synthesis of Staphylococcus aureus virulence factors is controlled by a density-sensing system that utilizes an octapeptide produced by the organism itself. The octapeptide activates expression of the agr locus, a global regulator of the virulence response. This response involves the reciprocal regulation of genes encoding surface proteins and those encoding secreted virulence factors. As cells enter the postexponential phase, surface protein genes are repressed by agr and secretory protein genes are subsequently activated. The intracellular agr effector is a regulatory RNA, RNAIII, whose transcription is activated by an agr-encoded signal transduction system for which the octapeptide is the ligand.

  1. DIAGNOSTIC VALUE OF DENSITY GRADIENT CENTRIFUGATION FOR EXFOLIATIVE TUMOR CELLS IN MALIGNANT PLEURAL EFFUSIONS

    Institute of Scientific and Technical Information of China (English)

    郭胤仕; 朱任之

    2004-01-01

    Objective To find out a specific method for diagnosis of malignant pleural effusions( MPEs )with higher sensitivity and practicality. Methods The diagnosis of MPEs were made using density gradient centrifugation ( DGC ) , smear cytologic examination (SCE) and pleural needle biopsy (PNB). Comparisons between these results and those of benign pleural effusions were also made. Results The positive rates of DGC,SCE and PNB for diagnosing MPEs were 94. 3% ,62.9% and 44.6% , respectively, and the positive rate of SCE combined with PNB for diagnosing MPEs was 73.2 %. The positive rate of the exfoliative tumor cells ( ETCs ) by DGC was much higher than that of SCE or/and PNB with no false-positive. Conclusion The ETCs isolated by DGC from the MPEs is quite specific for the diagnosis of malignant tumors with higher sensitivity and practicality in clinico-pathological practice.

  2. Leptin deficiency-induced obesity affects the density of mast cells in abdominal fat depots and lymph nodes in mice

    Directory of Open Access Journals (Sweden)

    Altintas Mehmet M

    2012-02-01

    Full Text Available Abstract Background Mast cells are implicated in the pathogenesis of obesity and insulin resistance. Here, we explored the effects of leptin deficiency-induced obesity on the density of mast cells in metabolic (abdominal fat depots, skeletal muscle, and liver and lymphatic (abdominal lymph nodes, spleen, and thymus organs. Fourteen-week-old male leptin-deficient ob/ob mice and their controls fed a standard chow were studied. Tissue sections were stained with toluidine blue to determine the density of mast cells. CD117/c-kit protein expression analysis was also carried out. Furthermore, mast cells containing immunoreactive tumor necrosis factor-α (TNF-α, a proinflammatory cytokine involved in obesity-linked insulin resistance, were identified by immunostaining. Results ob/ob mice demonstrated adiposity and insulin resistance. In abdominal fat depots, mast cells were distributed differentially. While most prevalent in subcutaneous fat in controls, mast cells were most abundant in epididymal fat in ob/ob mice. Leptin deficiency-induced obesity was accompanied by a 20-fold increase in the density of mast cells in epididymal fat, but a 13-fold decrease in subcutaneous fat. This finding was confirmed by CD117/c-kit protein expression analysis. Furthermore, we found that a subset of mast cells in epididymal and subcutaneous fat were immunoreactive for TNF-α. The proportion of mast cells immunoreactive for TNF-α was higher in epididymal than in subcutaneous fat in both ob/ob and control mice. Mast cells were also distributed differentially in retroperitoneal, mesenteric, and inguinal lymph nodes. In both ob/ob mice and lean controls, mast cells were more prevalent in retroperitoneal than in mesenteric and inguinal lymph nodes. Leptin deficiency-induced obesity was accompanied by increased mast cell density in all lymph node stations examined. No significant difference in the density of mast cells in skeletal muscle, liver, spleen, and thymus was

  3. Effects of oxidized low density lipoprotein on the growth of human artery smooth muscle cells

    Institute of Scientific and Technical Information of China (English)

    ZHAO Gao-feng; SENG Jing-jing; ZHANG Hua; SHE Ming-peng

    2005-01-01

    Background Studies have shown that oxidized low density lipoprotein (ox-LDL) promotes the pathogenesis and development of atherosclerosis (AS), and that the proliferation, migration and phenotype alteration of vascular smooth muscle cells (vSMCs) into foam cells are critical changes in AS. It is proposed that ox-LDL might play a novel role in the pathologic process of vSMCs. The present study was performed ex vivo to investigate the effects of ox-LDL on the growth of cultured human vSMCs.Methods Using NaBr density gradient centrifugation, LDL from human plasma was isolated and purified. ox-LDL was produced from LDL after being incubated with CuSO4. ox-LDL was then added to the culture medium at different concentrations (25 μg/ml, 50 μg/ml, 75 μg/ml, 100 μg/ml, 125 μg/ml, and 150 μg/ml) for 7 days. The influence of ox-LDL on vSMC growth was observed from several aspects as growth curve, mitosis index, lipid staining, and in situ determination of apoptosis. The digital results were analyzed with SPSS 10.0.Results The ox-LDL produced ex vivo had a good purity and optimal oxidative degree, which was similar to the intrinsic ox-LDL in atherosclerotic plaque. ox-LDL at a concentration of 25 μg/ml demonstrated the strongest proliferation. At the concentration of 125 μg/ml, ox-LDL suppressed the growth of vSMCs. At concentrations of 25 μg/ml and 50 μg/ml, ox-LDL presented powerful mitotic trigger. When the concentration of ox-LDL increased, the mitotic index of vSMCs decreased gradually. ox-LDL induced more foam cells from vSMCs with rich intracellular lipid accumulation at concentrations of 25 μg/ml and 50 μg/ml. ox-LDL at higher concentrations induced more apoptotic vSMCs.Conclusions ox-LDL at lower concentrations may trigger proliferation and phenotype alteration into foam cells of vSMCs, and at higher concentrations it may induce apoptosis in vSMCs. ox-LDL plays an important role in the pathogenesis and development of atherosclerosis by its effect on v

  4. Heterogeneity and glycan masking of cell wall microstructures in the stems of Miscanthus x giganteus, and its parents M. sinensis and M. sacchariflorus.

    Directory of Open Access Journals (Sweden)

    Jie Xue

    Full Text Available Plant cell walls, being repositories of fixed carbon, are important sources of biomass and renewable energy. Miscanthus species are fast growing grasses with a high biomass yield and they have been identified as potential bioenergy crops. Miscanthus x giganteus is the sterile hybrid between M. sinensis and M. sacchariflorus, with a faster and taller growth than its parents. In this study, the occurrence of cell wall polysaccharides in stems of Miscanthus species has been determined using fluorescence imaging with sets of cell wall directed monoclonal antibodies. Heteroxylan and mixed linkage-glucan (MLG epitopes are abundant in stem cell walls of Miscanthus species, but their distributions are different in relation to the interfascicular parenchyma and these epitopes also display different developmental dynamics. Detection of pectic homogalacturonan (HG epitopes was often restricted to intercellular spaces of parenchyma regions and, notably, the high methyl ester LM20 HG epitope was specifically abundant in the pith parenchyma cell walls of M. x giganteus. Some cell wall probes cannot access their target glycan epitopes because of masking by other polysaccharides. In the case of Miscanthus stems, masking of xyloglucan by heteroxylan and masking of pectic galactan by heteroxylan and MLG was detected in certain cell wall regions. Knowledge of tissue level heterogeneity of polysaccharide distributions and molecular architectures in Miscanthus cell wall structures will be important for both understanding growth mechanisms and also for the development of potential strategies for the efficient deconstruction of Miscanthus biomass.

  5. High density lipoprotein 3 inhibits oxidized low density lipoprotein-induced apoptosis via promoting cholesterol efflux in RAW264.7 cells

    Institute of Scientific and Technical Information of China (English)

    Pei JIANG; Peng-ke YAN; Jian-xiong CHEN; Bing-yang ZHU; Xiao-yong LEI; Wei-dong YIN; Duan-fang LIAO

    2006-01-01

    Aim: To investigate the protective effect of high density lipoprotein 3 (HDL3) on oxidized low density lipoprotein (ox-LDL)-induced apoptosis in RAW264.7 cells.Methods: RAW264.7 cells were exposed to 50 mg/L ox-LDL for various durations up to 48 h, and apoptosis was detected using Hoechst 33258 staining and flow cytometric analysis. Total cholesterol levels were detected by high performance liquid chromatography, cholesterol efflux was determined by Tritium labeling, and the cellular lipid droplets were assayed by oil red O staining. Results: Treatment with 50 mg/L ox-LDL for 12, 24, and 48 h increased the apoptotic rate of RAW264.7 cells in a time-dependent manner. The peak apoptotic rate (47.7%) was observed after 48 h incubation. HDL3 at various concentrations (50 mg/L, 100 mg/L, and 200mg/L) inhibited the ox-LDL (50 mg/L for 48 h)-mediated apoptosis that was accompanied by an increased rate of intracellular cholesterol efflux, and decreased total cholesterol levels in cells in a concentration-dependent manner. Blockage of cholesterol efflux by brefeldin decreased the protective effect of HDL3 on ox-LDL-induced apoptosis. Increase of the cholesterol efflux effected by another cholesterol acceptor, β-cyclodextrin, led to a dramatic decrease in the apoptotic rate of cells. Conclusion: HDL3 antagonizes ox-LDL-induced apoptosis in RAW264.7cells, through reducing the accumulation of toxic cholesterol.

  6. Inducing the migration behavior of endothelial cells by tuning the ligand density on a density-gradient poly(ethylene glycol) surface.

    Science.gov (United States)

    Li, Tiantian; Xu, Kui; Fu, Ya; Cai, Kaiyong

    2016-07-01

    The migration of endothelial cells (ECs) is crucially important for many biological processes, including early embryonic vasculogenesis, wound healing and angiogenesis. To investigate the effect of the surface poly(ethylene glycol) (mPEG-CHO) density on the migration of ECs, we developed a convenient and effective method to fabricate a series of silicon slides with graded PEG densities on their surfaces based on gradual treatment with 3-glycidoxypropyltrimethoxysilane (GPTMS), backfilling with 3-aminopropyltriethoxysilane (APTES) and subsequent conjugation of m-PEG. The PEG gradient was confirmed by X-ray photoelectron spectrometry (XPS), contact angle measurement and spectroscopic ellipsometry and determined to range from 0.56 to 0.75chains/nm(2). The impact of the PEG gradient on the EC migration was evaluated by real-time observation via a time-lapse phase-contrast microscope. ECs adhered to the silicon surfaces with high and modest PEG densities displayed a higher tendency of migration than those on corresponding non-graded samples. The results suggest that the motility of ECs could be modulated by the PEG gradient. This study would be helpful for understanding cell-substrate interactions. PMID:27058513

  7. Ovarian teratoma displaying a wide variety of tissue components in a broiler chicken (Gallus Domesticus: morphological heterogeneity of pluripotential germ cell during tumorigenesis

    Directory of Open Access Journals (Sweden)

    S. Ohfuji

    2016-05-01

    Full Text Available Spontaneous ovarian teratoma was found in a seven-week-old female Chunky broiler chicken that was slaughtered for food. On post-mortem inspection, a spherical tumor mass attaching to a juvenile ovary was found in the abdominal cavity. Histopathologically, the tumor was comprised of immature mesenchymal stroma and a variety of mature tissue elements of mesodermal and ectodermal origin. In addition, there were multiple indistinguishable tissue elements, which showed no malignant cytological features but were unidentifiable as to corresponding embryological layer of origin. These heterogeneous teratoma tissues consisted of a variety of glandular, cystic, duct-like, and tubular structures, some of which exhibited a lining by a mixture of both keratinizing/non-keratinizing stratified squamous epithelial cells and cuboidal/columnar epithelial cells. The ovarian tetatoma was considered a benign and congenital one. The highly diverse differentiation of the teratoma might have manifested a morphological aspect of intrinsic character of the pluripotential germ cells during tumorigenesis.

  8. Ovarian teratoma displaying a wide variety of tissue components in a broiler chicken (Gallus Domesticus): morphological heterogeneity of pluripotential germ cell during tumorigenesis.

    Science.gov (United States)

    Ohfuji, S

    2016-01-01

    Spontaneous ovarian teratoma was found in a seven-week-old female Chunky broiler chicken that was slaughtered for food. On post-mortem inspection, a spherical tumor mass attaching to a juvenile ovary was found in the abdominal cavity. Histopathologically, the tumor was comprised of immature mesenchymal stroma and a variety of mature tissue elements of mesodermal and ectodermal origin. In addition, there were multiple indistinguishable tissue elements, which showed no malignant cytological features but were unidentifiable as to corresponding embryological layer of origin. These heterogeneous teratoma tissues consisted of a variety of glandular, cystic, duct-like, and tubular structures, some of which exhibited a lining by a mixture of both keratinizing/non-keratinizing stratified squamous epithelial cells and cuboidal/columnar epithelial cells. The ovarian tetatoma was considered a benign and congenital one. The highly diverse differentiation of the teratoma might have manifested a morphological aspect of intrinsic character of the pluripotential germ cells during tumorigenesis. PMID:27303655

  9. Expression profiling on high-density DNA grids to detect novel targets in dendritic cells

    International Nuclear Information System (INIS)

    Gene expression analyzes on a large scale using DNA microarrays is a novel approach to study transcription of thousands of genes in parallel. By comparing gene expression profiles of different cell-types and of cells in different activation, novel regulatory networks will be identified that are unique to a cell-type and hence, important in its biological function. Among the differentially expressed genes many novel drug targets will be found. The Genetic department of the Novartis Research Institute was following this approach to identify novel genes, which are critical in the antigen presenting function of DCs and could become promising drug targets. Drugs that modulate effector functions of DCs towards induction of energy or tolerance in T-cells could be useful in the treatment of chronic inflammatory or autoimmune diseases. By using specific robotics equipment high-density cDNA grids on nylon membranes have been produced for hybridizations with various radioactive labeled DNA probes. By our format, based on 384 well plates and limited by the resolution power of our current image analysis software, 27.648 cDNA clones, bacterial colonies or pure DNA, were spotted on one filter. For RNA profiling, we generated filters containing a collection of genes expressed in peripheral blood DCs or monocytes and characterized by oligonucleotide fingerprinting (ONF) as being differentially expressed. The gene collection contained many unknown genes. Sequence analysis of to date 18.000 cDNA clones led to an estimate of 5.000 non-redundant genes being represented in the collection. 10 % of them are either completely unknown or homologous to rare ESTs (expressed sequence tags) in the public EST database. These clones occurred predominantly in small fingerprint clusters and were therefore assumed to be rarely expressed in DCs or monocytes. Some of those genes may become novel drug targets if their expression is DC specific or induced by external stimuli driving DCs into

  10. Effect of porosity heterogeneity on the permeability and tortuosity of gas diffusion layers in polymer electrolyte membrane fuel cells

    Science.gov (United States)

    Nabovati, Aydin; Hinebaugh, James; Bazylak, Aimy; Amon, Cristina H.

    2014-02-01

    In this paper, we study the effect of porosity heterogeneity on the bulk hydrodynamic properties (permeability and tortuosity) of simulated gas diffusion layers (GDLs). The porosity distributions of the heterogeneous reconstructed samples are similar to those previously reported in the literature for Toray TGP-H 120™ GDLs. We use the lattice Boltzmann method to perform pore-level flow simulations in the reconstructed GDL samples. Using the results of pore-level simulations, the effect of porosity distribution is characterized on the predicted in- and cross-plane permeability and tortuosity. It was found that porosity heterogeneity causes a higher in-plane permeability and lower in-plane tortuosity, while the effect is opposite in the cross-plane direction, that is a lower cross-plane permeability and a higher cross-plane tortuosity. We further investigate the effect of adding poly-tetra-fluoro-ethylene (PTFE) & binder material to the reconstructed GDL samples. Three fiber volume percentages of 50, 75, and 100% are considered. Overall, increasing the fiber volume percentage reduces the predicted in- and cross-plane permeability and tortuosity values. A previously reported relationship for permeability of fibrous materials is fitted to the predicted permeability values, and the magnitude of the fitting parameter is reported as a function of fiber volume percentage.

  11. High-Density and Very-Low-Density Lipoprotein Have Opposing Roles in Regulating Tumor-Initiating Cells and Sensitivity to Radiation in Inflammatory Breast Cancer

    International Nuclear Information System (INIS)

    Purpose: We previously demonstrated that cholesterol-lowering agents regulate radiation sensitivity of inflammatory breast cancer (IBC) cell lines in vitro and are associated with less radiation resistance among IBC patients who undergo postmastectomy radiation. We hypothesized that decreasing IBC cellular cholesterol induced by treatment with lipoproteins would increase radiation sensitivity. Here, we examined the impact of specific transporters of cholesterol (ie lipoproteins) on the responses of IBC cells to self-renewal and to radiation in vitro and on clinical outcomes in IBC patients. Methods and Materials: Two patient-derived IBC cell lines, SUM 149 and KPL4, were incubated with low-density lipoproteins (LDL), very-low-density lipoproteins (VLDL), or high-density lipoproteins (HDL) for 24 hours prior to irradiation (0-6 Gy) and mammosphere formation assay. Cholesterol panels were examined in a cohort of patients with primary IBC diagnosed between 1995 and 2011 at MD Anderson Cancer Center. Lipoprotein levels were then correlated to patient outcome, using the log rank statistical model, and examined in multivariate analysis using Cox regression. Results: VLDL increased and HDL decreased mammosphere formation compared to untreated SUM 149 and KPL4 cells. Survival curves showed enhancement of survival in both of the IBC cell lines when pretreated with VLDL and, conversely, radiation sensitization in all cell lines when pretreated with HDL. In IBC patients, higher VLDL values (>30 mg/dL) predicted a lower 5-year overall survival rate than normal values (hazard ratio [HR] = 1.9 [95% confidence interval [CI]: 1.05-3.45], P=.035). Lower-than-normal patient HDL values (<60 mg/dL) predicted a lower 5-year overall survival rate than values higher than 60 mg/dL (HR = 3.21 [95% CI: 1.25-8.27], P=.015). Conclusions: This study discovered a relationship among the plasma levels of lipoproteins, overall patient response, and radiation resistance in IBC patients

  12. High-Density and Very-Low-Density Lipoprotein Have Opposing Roles in Regulating Tumor-Initiating Cells and Sensitivity to Radiation in Inflammatory Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, Adam R. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Atkinson, Rachel L. [Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Reddy, Jay P. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Debeb, Bisrat G.; Larson, Richard; Li, Li [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Clinical Cancer Prevention, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Masuda, Hiroko; Brewer, Takae [Department of Clinical Cancer Prevention, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Atkinson, Bradley J. [Department of Clinical Pharmacy Services, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Brewster, Abeena [Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Ueno, Naoto T. [Department of Clinical Cancer Prevention, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Woodward, Wendy A., E-mail: wwoodward@mdanderson.org [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Clinical Cancer Prevention, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2015-04-01

    Purpose: We previously demonstrated that cholesterol-lowering agents regulate radiation sensitivity of inflammatory breast cancer (IBC) cell lines in vitro and are associated with less radiation resistance among IBC patients who undergo postmastectomy radiation. We hypothesized that decreasing IBC cellular cholesterol induced by treatment with lipoproteins would increase radiation sensitivity. Here, we examined the impact of specific transporters of cholesterol (ie lipoproteins) on the responses of IBC cells to self-renewal and to radiation in vitro and on clinical outcomes in IBC patients. Methods and Materials: Two patient-derived IBC cell lines, SUM 149 and KPL4, were incubated with low-density lipoproteins (LDL), very-low-density lipoproteins (VLDL), or high-density lipoproteins (HDL) for 24 hours prior to irradiation (0-6 Gy) and mammosphere formation assay. Cholesterol panels were examined in a cohort of patients with primary IBC diagnosed between 1995 and 2011 at MD Anderson Cancer Center. Lipoprotein levels were then correlated to patient outcome, using the log rank statistical model, and examined in multivariate analysis using Cox regression. Results: VLDL increased and HDL decreased mammosphere formation compared to untreated SUM 149 and KPL4 cells. Survival curves showed enhancement of survival in both of the IBC cell lines when pretreated with VLDL and, conversely, radiation sensitization in all cell lines when pretreated with HDL. In IBC patients, higher VLDL values (>30 mg/dL) predicted a lower 5-year overall survival rate than normal values (hazard ratio [HR] = 1.9 [95% confidence interval [CI]: 1.05-3.45], P=.035). Lower-than-normal patient HDL values (<60 mg/dL) predicted a lower 5-year overall survival rate than values higher than 60 mg/dL (HR = 3.21 [95% CI: 1.25-8.27], P=.015). Conclusions: This study discovered a relationship among the plasma levels of lipoproteins, overall patient response, and radiation resistance in IBC patients

  13. Comparison of ultracentrifugation and density gradient separation methods for isolating Tca8113 human tongue cancer cell line-derived exosomes

    OpenAIRE

    Zhang, Zhuoyuan; Wang, Chenxing; Li, Tang; LIU, ZHE; LI, LONGJIANG

    2014-01-01

    The aim of the present study was to compare the method of ultracentrifugation and density gradient separation for isolating Tca8113 human tongue squamous cell carcinoma cell line-derived exosomes. The exosomes were obtained from the culture supernatant of cultured Tca8113 cells, respectively, followed by identification with transmission electron microscopy observation and western blot analysis. The two different methods were then compared by the morphology, the distribution range of the parti...

  14. Changes in small intestinal chromogranin A-immunoreactive cell densities in patients with irritable bowel syndrome after receiving dietary guidance.

    Science.gov (United States)

    Mazzawi, Tarek; El-Salhy, Magdy

    2016-05-01

    Chromogranin A (CgA) is a common marker for enteroendocrine cells in the gut, and CgA-immunoreactive cell densities are abnormal in patients with irritable bowel syndrome (IBS). The majority of patients with IBS report that their symptoms develop after consuming certain foodstuffs. In the present study, we investigated the effects of dietary guidance on the total enteroendocrine cell densities in the small intestine, as detected by CgA. A total of 14 patients with IBS underwent a gastroscopy with duodenal biopsies and 11 of them also underwent a colonoscopy, with biopsy samples obtained from the ileum. Fourteen control subjects were also included. Each patient received 3 sessions of dietary guidance. Gastroscopies and colonoscopies were performed on both the controls and patients with IBS (at baseline and at 3-9 months after receiving guidance). Biopsy samples obtained from the duodenum and ileum were immunostained for CgA using the avidin-biotin complex (ABC) method and were quantified using computerized image analysis. The density of CgA-immunoreactive cells in the duodenum (mean ± SEM values) in the control subjects was 235.9 ± 31.9 cells/mm2; in the patients with IBS, the density was 36.9 ± 9.8 and 103.7 ± 16.9 cells/mm2 before and after they received dietary guidance, respectively (P=0.007). The density of CgA-immunoreactive cells in the ileum in the control subjects was 47.4 ± 8.3 cells/mm2; in the patients with IBS, the density was 48.4 ± 8.1 and 17.9 ± 4.4 cells/mm2, before and after they received dietary guidance, respectively (P=0.0006). These data indicate that changes in CgA-immunoreactive cell densities in patients with IBS after receiving dietary guidance may reflect a change in the densities of the small intestinal enteroendocrine cells, which may contribute to an improvement in the IBS symptoms. PMID:26987104

  15. Melanoma cells show a heterogeneous range of sensitivity to ionizing radiation and are radiosensitized by inhibition of B-RAF with PLX-4032

    International Nuclear Information System (INIS)

    Purpose: To assess the relative radiosensitivities of a large collection of melanoma cell lines and to determine whether pharmacologic inhibition of mutant B-RAF with PLX-4032 can radiosensitize B-Raf+ melanoma cells. Materials and methods: A large collection of melanoma cell lines (n = 37) were treated with 0-8 Gy IR and clonogenic survival assays used to generate survival curves to rank relative radiosensitivities among the cell lines. The ability of a B-RAF inhibitor, PLX-4032, to radiosensitize highly radioresistant B-Raf+ cells was also assessed by clonogenic cell survival and spheroid invasion assays and the effects of treatment on the cell cycle assessed by FACS. Results: Melanoma cell lines displayed a very large, heterogeneous range of SF2 values (1.002-0.053) with a mean of 0.51. Cell lines with surviving fractions of 0.29 or less at SF2 and SF4 were observed at a high frequency of 18.9% and 70.2%, respectively. Treatment of B-Raf+ cells with the B-RAF inhibitor PLX-4032 in combination with radiation provided enhanced inhibition of both colony formation and invasion, and radiosensitized cells through an increase in G1 arrest. Conclusions: Our data suggest that melanomas are not uniformly radioresistant with a significant subset displaying inherent radiosensitivity. Pharmacologic inhibition of B-RAF with PLX-4032 effectively radiosensitized B-Raf+ melanoma cells suggesting that this combination approach could provide improved radiotherapeutic response in B-Raf+ melanoma patients.

  16. Effectiveness of electroacupuncture at Zusanli (ST36) on the immunohistochemical density of enteroendocrine cells related to gastrointestinal function.

    Science.gov (United States)

    Lee, Chang Hyun; Kim, Dae-Keun; Yook, Tae-Han; Sasaki, Motoki; Kitamura, Nobuo

    2012-04-01

    The purpose of this study was to examine the effects of electroacupuncture at Zusanli on the immunohistochemical density of enteroendocrine cells related to gastrointestinal function. The authors investigated the histochemical changes of mucous substances and immunohistochemical density of gastrin, serotonin, calcitonin gene-related peptide (CGRP), insulin, and pancreatic polypeptide (PP) secreting cells in rats. Staining density of mucous substances and the enteroendocrine cells of the gastrointestinal tract was observed with histochemical and immunohistochemical methods. Stainless steel needles with a diameter of 0.25 mm were inserted into Zusanli (St36, 5mm below the head of the fibula under the knee joint, and 2mm lateral to the anterior tubercle of the tibia) and connected to an electrical stimulator. The electroacupuncture (EA) stimulation was delivered for 30 minutes at 10 mA, 2 Hz in EA stimulation (2EA group) or 4 Hz in EA stimulation (4EA group) in each experimental group. In 4EA stimulation at the Zusanli, staining density of Alcian blue-periodic acid-Schiff on mucous substances of the stomach body was stronger than those of the 2EA and control groups. Periodic acid-Schiff staining density of pyloric mucosa in the 4EA group was stronger than that of the 2EA and control groups. The immunohistochemical staining density of gastrin, serotonin, and CGRP-secreting cells of pylorus in the 2EA and 4EA groups was stronger than that of the control group. Immunohistochemical staining density of insulin and PP secreting cells of islets of the pancreas in the 2EA and 4EA groups was stronger than that of the control group. These results suggest that EA stimulus at St36 has the potential to influence gastric mucous substances and enteroendocrine cells (gastrin, serotonin, CGRP, insulin, and PP) that subsequently modulate digestive functions. PMID:22483184

  17. Changes in Surface Charge Density of Blood Cells in Fatal Accidental Hypothermia.

    Science.gov (United States)

    Szeremeta, Michał; Petelska, Aneta Dorota; Kotyńska, Joanna; Pepiński, Witold; Naumowicz, Monika; Figaszewski, Zbigniew Artur; Niemcunowicz-Janica, Anna

    2015-12-01

    The objective of this research was to evaluate postmortem changes concerning electric charge of human erythrocytes and thrombocytes in fatal accidental hypothermia. The surface charge density values were determined on the basis of the electrophoretic mobility measurements of the cells conducted at various pH values of electrolyte solution. The surface charge of erythrocyte membranes after fatal accidental hypothermia increased compared to the control group within whole range of experimental pH values. Moreover, a slight shift of the isoelectric point of erythrocyte membranes towards high pH values was observed. The surface charge of thrombocyte membranes in fatal accidental hypothermia decreased at low pH compared to the control group. However, at pH range 4-9, the values increased compared to the control group. The isoelectric point of thrombocyte membranes after fatal accidental hypothermia was slightly shifted towards low pH values compared to the control group. The observed changes are probably connected with the partial destruction and functional changes of the blood cell structure. PMID:26364031

  18. Optimized LTE Cell Planning with Varying Spatial and Temporal User Densities

    KAUST Repository

    Ghazzai, Hakim

    2015-03-09

    Base station deployment in cellular networks is one of the fundamental problems in network design. This paper proposes a novel method for the cell planning problem for the fourth generation (4G) cellular networks using meta-heuristic algorithms. In this approach, we aim to satisfy both cell coverage and capacity constraints simultaneously by formulating an optimization problem that captures practical planning aspects. The starting point of the planning process is defined through a dimensioning exercise that captures both coverage and capacity constraints. Afterwards, we implement a meta-heuristic algorithm based on swarm intelligence (e.g., particle swarm optimization or the recently-proposed grey wolf optimizer) to find suboptimal base station locations that satisfy both problem constraints in the area of interest which can be divided into several subareas with different spatial user densities. Subsequently, an iterative approach is executed to eliminate eventual redundant base stations. We also perform Monte Carlo simulations to study the performance of the proposed scheme and compute the average number of users in outage. Next, the problems of green planning with regards to temporal traffic variation and planning with location constraints due to tight limits on electromagnetic radiations are addressed, using the proposed method. Finally, in our simulation results, we apply our proposed approach for different scenarios with different subareas and user distributions and show that the desired network quality of service targets are always reached even for large-scale problems.

  19. Optimized LTE cell planning for multiple user density subareas using meta-heuristic algorithms

    KAUST Repository

    Ghazzai, Hakim

    2014-09-01

    Base station deployment in cellular networks is one of the most fundamental problems in network design. This paper proposes a novel method for the cell planning problem for the fourth generation 4G-LTE cellular networks using meta heuristic algorithms. In this approach, we aim to satisfy both coverage and cell capacity constraints simultaneously by formulating a practical optimization problem. We start by performing a typical coverage and capacity dimensioning to identify the initial required number of base stations. Afterwards, we implement a Particle Swarm Optimization algorithm or a recently-proposed Grey Wolf Optimizer to find the optimal base station locations that satisfy both problem constraints in the area of interest which can be divided into several subareas with different user densities. Subsequently, an iterative approach is executed to eliminate eventual redundant base stations. We have also performed Monte Carlo simulations to study the performance of the proposed scheme and computed the average number of users in outage. Results show that our proposed approach respects in all cases the desired network quality of services even for large-scale dimension problems.

  20. Aggregation on heterogeneous surface

    Institute of Scientific and Technical Information of China (English)

    Lu Hang-Jun; Wu Feng-Min; Fang Yun-Zhang

    2004-01-01

    Chessboard-like substrates are introduced in this paper, in order to study the diffusion-limited aggregation (DLA)and the motion of poly-atoms on heterogeneous surfaces. The effect of morphology of such substrates upon the cluster aggregation is investigated using the Monte Carlo simulation. It is found that the growth process and the cluster morphology are governed by the energetic topography of the substrates. Our simulation also indicate that the island density and the fractal dimension of the clusters depend strongly on the substrate topography and the activation energy.

  1. Microvessel density and heparanase over-expression in clear cell renal cell cancer: correlations and prognostic significances

    Directory of Open Access Journals (Sweden)

    Ren Juchao

    2011-12-01

    Full Text Available Abstract Background Tumor angiogenesis is important in the progression of malignancies, and heparanase plays an important role in sustaining the pathology of clear cell renal cell cancer (ccRCC. The study was carried out to investigate the correlations between microvessel density (MVD and heparanase expression containing prognostic significances in the patients with ccRCC. Methods Specimens from 128 patients with ccRCC were investigated by immunohistochemistry for MVD. RT-PCR and immunohistochemistry were used to detect heparanase expression. Correlations between MVD, heparanase expression, and various clinico-pathological factors were studied. The prognostic significances of MVD and heparanase expression were also analysed. Results We discovered a statistically significant prevalence of higher MVD in ccRCC compared with adjacent normal renal tissues. MVD was positively correlated with TNM stage and distant metastasis in ccRCC patients, and was also correlated with the expression level of heparanase. Heparanase is over-expressed and correlated with TNM stage, histologic grade, distant metastasis and lymphatic metastasis in ccRCC. High MVD and heparanase over-expression inversely correlate with the survival of ccRCC patients. Conclusions Heparanase contributes to angiogenesis of ccRCC and over-expression of heparanase is an independent predictors of prognosis for ccRCC. MVD is correlated with tumor development and metastasis in ccRCC.

  2. Comparison of Transcriptional Heterogeneity of Eight Genes between Batch Desulfovibrio vulgaris Biofilm and Planktonic Culture at a Single-Cell Level

    Science.gov (United States)

    Qi, Zhenhua; Chen, Lei; Zhang, Weiwen

    2016-01-01

    Sulfate-reducing bacteria (SRB) biofilm formed on metal surfaces can change the physicochemical properties of metals and cause metal corrosion. To enhance understanding of differential gene expression in Desulfovibrio vulgaris under planktonic and biofilm growth modes, a single-cell based RT-qPCR approach was applied to determine gene expression levels of 8 selected target genes in four sets of the 31 individual cells isolated from each growth condition (i.e., biofilm formed on a mild steel (SS) and planktonic cultures, exponential and stationary phases). The results showed obvious gene-expression heterogeneity for the target genes among D. vulgaris single cells of both biofilm and planktonic cultures. In addition, an increased gene-expression heterogeneity in the D. vulgaris biofilm when compared with the planktonic culture was also observed for seven out of eight selected genes at exponential phase, and six out of eight selected genes at stationary phase, respectively, which may be contributing to the increased complexity in terms of structures and morphology in the biofilm. Moreover, the results showed up-regulation of DVU0281 gene encoding exopolysaccharide biosynthesis protein, and down-regulation of genes involved in energy metabolism (i.e., DVU0434 and DVU0588), stress responses (i.e., DVU2410) and response regulator (i.e., DVU3062) in the D. vulgaris biofilm cells. Finally, the gene (DVU2571) involved in iron transportation was found down-regulated, and two genes (DVU1340 and DVU1397) involved in ferric uptake repressor and iron storage were up-regulated in D. vulgaris biofilm, suggesting their possible roles in maintaining normal metabolism of the D. vulgaris biofilm under environments of high concentration of iron. This study showed that the single-cell based analysis could be a useful approach in deciphering metabolism of microbial biofilms. PMID:27199927

  3. Comparison of transcriptional heterogeneity of eight genes between batch Desulfovibrio vulgaris biofilm and planktonic culture at a single-cell level

    Directory of Open Access Journals (Sweden)

    Zhenhua eQi

    2016-04-01

    Full Text Available Sulfate-reducing bacteria (SRB biofilm formed on metal surfaces can change the physicochemical properties of metals and cause metal corrosion. To enhance understanding of differential gene expression in Desulfovibrio vulgaris under planktonic and biofilm growth modes, a single-cell based RT-qPCR approach was applied to determine gene expression levels of 8 selected target genes in four sets of the 31 individual cells isolated from each growth condition (i.e., biofilm formed on a stainless steel (SS) and planktonic cultures, exponential and stationary phases. The results showed obvious gene-expression heterogeneity for the target genes among D. vulgaris single cells of both biofilm and planktonic cultures. In addition, an increased gene-expression heterogeneity in the D. vulgaris biofilm when compared with the planktonic culture was also observed for seven out of eight selected genes, which may be contributing to the increased complexity in terms of structures and morphology in the biofilm. Moreover, the results showed up-regulation of DVU0281 gene encoding exopolysaccharide biosynthesis protein, and down-regulation of genes involved in energy metabolism (i.e., DVU0434 and DVU0588, stress responses (i.e., DVU2410 and response regulator (i.e., DVU3062 in the D. vulgaris biofilm cells. Finally, the gene (DVU2571 involved in iron transportation was found down-regulated, and two genes (DVU1340 and DVU1397 involved in ferric uptake repressor and iron storage were up-regulated in D. vulgaris biofilm, suggesting their possible roles in maintaining normal metabolism of the D. vulgaris biofilm under environments of high concentration of iron. This study showed that the single-cell based analysis could be a useful approach in deciphering metabolism of microbial biofilms.

  4. Heterogeneity in gamma-glutamyltransferase mRNA expression and glycan structures. Search for tumor-specific variants in human liver metastases and colon carcinoma cells.

    Science.gov (United States)

    Pettersen, Ingvild; Andersen, Jeanette Hammer; Bjornland, Kristin; Mathisen, Øystein; Bremnes, Roy; Wellman, Maria; Visvikis, Athanase; Huseby, Nils-Erik

    2003-05-30

    The enzyme gamma-glutamyltransferase (GGT) is frequently overexpressed in cancer cells and tissues and has significant utility as a cancer marker. Significant heterogeneity of the enzyme has been described due to both transcriptional and post-translational variations. For possible use in diagnosis and follow-up of patients with colorectal cancer, a search was performed for specific mRNA subtypes and glycan structures of the enzyme in liver metastases. We found no differences in the distribution of three GGT mRNA subtypes (fetal liver, HepG2, placenta) in metastatic tissue and normal liver tissue. Furthermore, the three subtypes were present in leukocytes isolated from both normal individuals and cancer patients. Two colon carcinoma cell lines (Colo 205 and HCC 2998) also displayed the three forms and no consistent changes in mRNA composition were noted after butyrate-induced differentiation of the cells. Thus, neither of the GGT mRNA subforms appear to be tumor-specific, although some qualitative and quantitative variations were noted. Two distinct glycosylation features were detected for GGT in metastatic tissue in contrast to normal liver GGT; an extreme sialic acid heterogeneity and a significant increase in beta1,6GlcNAc branching. The GGT glycans from the two colon carcinoma cell lines also possessed these features. As butyrate treatment of the cells resulted in an increased sialic acid content and a reduced beta1,6GlcNAc branching, the described carbohydrate structures appear to be part of a tumor-related pattern. We were, however, unable to identify such GGT isoforms in serum from patients with advanced colorectal cancer. This indicates that their usefulness in diagnostic use is doubtful. PMID:12758164

  5. The joint statistics of mildly non-linear cosmological densities and slopes in count-in-cells

    OpenAIRE

    Bernardeau, Francis; Codis, Sandrine; Pichon, Christophe

    2015-01-01

    In the context of count-in-cells statistics, the joint probability distribution of the density in two concentric spherical shells is predicted from first first principle for sigmas of the order of one. The agreement with simulation is found to be excellent. This statistics allows us to deduce the conditional one dimensional probability distribution function of the slope within under dense (resp. overdense) regions, or of the density for positive or negative slopes. The former conditional dist...

  6. Serum amyloid A stimulates macrophage foam cell formation via lectin-like oxidized low-density lipoprotein receptor 1 upregulation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ha Young, E-mail: hayoung@skku.edu [Department of Biological Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Mitochondria Hub Regulation Center, Dong-A University, Busan 602-714 (Korea, Republic of); Kim, Sang Doo [Department of Biological Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Baek, Suk-Hwan [Department of Biochemistry and Molecular Biology, College of Medicine, Yeungnam University, Daegu 705-717 (Korea, Republic of); Choi, Joon Hyuk [Department of Pathology, College of Medicine, Yeungnam University, Daegu 705-717 (Korea, Republic of); Cho, Kyung-Hyun [School of Biotechnology, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Zabel, Brian A. [Palo Alto Institute for Research and Education, Veterans Affairs Hospital, Palo Alto, CA 94304 (United States); Bae, Yoe-Sik, E-mail: yoesik@skku.edu [Department of Biological Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Mitochondria Hub Regulation Center, Dong-A University, Busan 602-714 (Korea, Republic of); Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul 135-710 (Korea, Republic of)

    2013-03-29

    Highlights: ► SAA induced macrophage foam cell formation. ► SAA stimulated upregulation of lectin-like oxidized low-density lipoprotein receptor 1 (LOX1). ► SAA-induced LOX1 expression and foam cell formation is mediated by JNK/NF-κB signaling. ► HDL-conjugated SAA also stimulates foam cell formation via LOX1 upregulation. ► The finding reveals a novel mechanism of action of SAA in the pathogenesis of atherosclerosis. -- Abstract: Elevated levels of serum amyloid A (SAA) is a risk factor for cardiovascular diseases, however, the role of SAA in the pathophysiology of atherosclerosis remains unclear. Here we show that SAA induced macrophage foam cell formation. SAA-stimulated foam cell formation was mediated by c-jun N-terminal kinase (JNK) signaling. Moreover, both SAA and SAA-conjugated high density lipoprotein stimulated the expression of the important scavenger receptor lectin-like oxidized low-density lipoprotein receptor 1 (LOX1) via nuclear factor-κB (NF-κB). A LOX1 antagonist carrageenan significantly blocked SAA-induced foam cell formation, indicating that SAA promotes foam cell formation via LOX1 expression. Our findings therefore suggest that SAA stimulates foam cell formation via LOX1 induction, and thus likely contributes to atherogenesis.

  7. Self-consistent particle-in-cell modelling of short pulse absorption and transport for high energy density physics experiments

    Science.gov (United States)

    Ramsay, M. G.; Arber, T. D.; Sircombe, N. J.

    2016-03-01

    In order for detailed, solid density particle-in-cell (PIC) simulations to run within a reasonable time frame, novel approaches to modelling high density material must be employed. For the purposes of modelling high intensity, short pulse laser-plasma interactions, however, these approaches must be consistent with retaining a full PIC model in the low-density laser interaction region. By replacing the standard Maxwell field solver with an electric field update based on a simplified Ohm's law in regions of high electron density, it is possible to access densities at and above solid without being subject to the standard grid and time step constraints. Such a model has recently been implemented in the PIC code EPOCH. We present the initial results of a detailed two-dimensional simulation performed to compare the adapted version of the code with recent experimental results from the Orion laser facility.

  8. NUMERICAL SIMULATION OF EFFECTS OF WALL THICKNESS AND CELL DENSITY ON THE THREE-WAY CATALYTIC CONVERTER PERFORMANCE

    Institute of Scientific and Technical Information of China (English)

    Wu Guojiang; Tan Song; Huang Zhen

    2005-01-01

    The transient symmetric mathematical model is established, and the effects of the wall thickness and cell density on the performance of a three-way catalytic converter are studied using numerical modeling. The conclusions show that the light-off time and the pressure drop through a converter are decreased, and the conversion efficiency during the warm-up period keeps almost invariant with reduction of the wall thickness of substrates, and that the pressure drop through a converter and a conversion efficiency during the warm-up state increases, and the light-off time almost keeps invariant when increasing cell density of substrates. Therefore, future catalytic converters should develop in the direction of thin wall thickness and high cell density substrates simultaneously.

  9. Molecular Genetic Alterations in Renal Cell Carcinomas With Tubulocystic Pattern: Tubulocystic Renal Cell Carcinoma, Tubulocystic Renal Cell Carcinoma With Heterogenous Component and Familial Leiomyomatosis-associated Renal Cell Carcinoma. Clinicopathologic and Molecular Genetic Analysis of 15 Cases.

    Science.gov (United States)

    Ulamec, Monika; Skenderi, Faruk; Zhou, Ming; Krušlin, Božo; Martínek, Petr; Grossmann, Petr; Peckova, Kvetoslava; Alvarado-Cabrero, Isabel; Kalusova, Kristyna; Kokoskova, Bohuslava; Rotterova, Pavla; Hora, Milan; Daum, Ondrej; Dubova, Magdalena; Bauleth, Kevin; Slouka, David; Sperga, Maris; Davidson, Whitney; Rychly, Boris; Perez Montiel, Delia; Michal, Michal; Hes, Ondrej

    2016-08-01

    The characteristic morphologic spectrum of tubulocystic renal cell carcinoma (TC-RCC) may include areas resembling papillary RCC (PRCC). Our study includes 15 RCCs with tubulocystic pattern: 6 TC-RCCs, 1 RCC-high grade with tubulocystic architecture, 5 TC-RCCs with foci of PRCC, 2 with high-grade RCC (HGRCC) not otherwise specified, and 1 with a clear cell papillary RCC/renal angiomyoadenomatous tumor-like component. We analyzed aberrations of chromosomes 7, 17, and Y; mutations of VHL and FH genes; and loss of heterozygosity at chromosome 3p. Genetic analysis was performed separately in areas of classic TC-RCC and in those with other histologic patterns. The TC-RCC component demonstrated disomy of chromosome 7 in 9/15 cases, polysomy of chromosome 17 in 7/15 cases, and loss of Y in 1 case. In the PRCC component, 2/3 analyzable cases showed disomy of chromosome 7 and polysomy of chromosome 17 with normal Y. One case with focal HGRCC exhibited only disomy 7, whereas the case with clear cell papillary RCC/renal angiomyoadenomatous tumor-like pattern showed polysomies of 7 and 17, mutation of VHL, and loss of heterozygosity 3p. FH gene mutation was identified in a single case with an aggressive clinical course and predominant TC-RCC pattern. The following conclusions were drawn: (1) TC-RCC demonstrates variable status of chromosomes 7, 17, and Y even in cases with typical/uniform morphology. (2) The biological nature of PRCC/HGRCC-like areas within TC-RCC remains unclear. Our data suggest that heterogenous TC-RCCs may be associated with an adverse clinical outcome. (3) Hereditary leiomyomatosis-associated RCC can be morphologically indistinguishable from "high-grade" TC-RCC; therefore, in TC-RCC with high-grade features FH gene status should be tested. PMID:26447894

  10. The large-scale correlations of multi-cell densities and profiles, implications for cosmic variance estimates

    CERN Document Server

    Codis, Sandrine; Pichon, Christophe

    2016-01-01

    In order to quantify the error budget in the measured probability distribution functions of cell densities, the two-point statistics of cosmic densities in concentric spheres is investigated. Bias functions are introduced as the ratio of their two-point correlation function to the two-point correlation of the underlying dark matter distribution. They describe how cell densities are spatially correlated. They are computed here via the so-called large deviation principle in the quasi-linear regime. Their large-separation limit is presented and successfully compared to simulations for density and density slopes: this regime is shown to be rapidly reached allowing to get sub-percent precision for a wide range of densities and variances. The corresponding asymptotic limit provides an estimate of the cosmic variance of standard concentric cell statistics applied to finite surveys. More generally, no assumption on the separation is required for some specific moments of the two-point statistics, for instance when pre...

  11. [High cell-density fermentation of shark hepatical stimulator analogue in Escherichia coli].

    Science.gov (United States)

    Ye, Boping; Pan, Zheng; Li, Huaibiao; Wang, Ying; Zheng, Heng; Wu, Wutong

    2009-09-01

    The potential effects of recombinant shark hepatical stimulator analogue (r-sHSA) in liver disease have been revealed in our previous studies. In order to further evaluate its clinic application, we carried out high cell-density fermentation in 5 L fermentor to get enough products. Based on the trials in shaking flask, we optimized the parameters for 5 L fermentor, including medium composition, medium supplement, inducer concentration and induction time, etc. In detail, the improved LB medium (0.97% glycerol, 0.91% yeast extract, 0.72% tryptone, 0.782% KH2PO4, 0.267% K2HPO4.3H2O, 0.062% MgSO4.7H2O, 0.5% NaCl, pH 7.0) is chosen to cultivate the engineering bacteria with the constant fermentation condition (pH 7.0, and the dissolved oxygen concentration is about 25%-30%). When bacterial culture reaches exponential phase, the modified feeding medium (620 g/L glycerol, 94.8 g/L tryptone, 3.3 mL/L trace elements, and 7.5 g/L MgSO4.7H2O) is then supplied through the method of exponential fed-batch mode. After the optical density (OD600) of engineering bacterial culture reaches to 23, the ultimately concentration of 0.5 mmol/L IPTG is added to induce the expression of r-sHSA for 6 h. Results show that the amount of r-sHSA production is (2.662 +/- 0.041) g/L, which is about 13.7 folds of the one optimized before. PMID:19938481

  12. Fast Nongenomic Effect of Aldosterone on the Volume of Principal Cells in Collecting Tube and Genetic Heterogeneity of Epithelial Sodium Channel in the Postnatal Ontogenesis of Rat Kidney.

    Science.gov (United States)

    Logvinenko, N S; Gerbek, Yu E; Solenov, E I; Ivanova, L N

    2016-03-01

    The effects of amiloride, epithelial sodium pump inhibitor, on the fast nongenomic effect of aldosterone in principal cells of an isolated segment of the distal portion of renal collecting tubes were studied in 10-day-old and adult rats. Fluorescent staining with Calcein AM showed various effects of amiloride (10(-5) M) on the stabilizing effect of aldosterone (10 nM) in hypotonic shock (280/140 mOsm/kg). Amiloride attenuated by 30% the effect of aldosterone on the amplitude of principal cell swelling in adult animals and almost completely abolished this effect in 10-day rats (p<0.05). These age-specific differences in the contribution of the distal portion of the collecting tube to the nongenomic effect of aldosterone did not depend on genetic heterogeneity of its α-subunit. PMID:27021081

  13. Argyrophil cell density in the oxyntic mucosa is higher in female than in male morbidly obese patients

    Energy Technology Data Exchange (ETDEWEB)

    Maksud, F.A.N. [Laboratório de Patologia Digestiva e Neuroendócrina, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil); Faculdade de Medicina, Universidade Federal de Ouro Preto, Ouro Preto, MG (Brazil); Kakehasi, A.M. [Laboratório de Patologia Digestiva e Neuroendócrina, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil); Barbosa, A.J.A. [Laboratório de Patologia Digestiva e Neuroendócrina, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil); Instituto Alfa de Gastroenterologia, Belo Horizonte, MG (Brazil)

    2013-04-05

    Obesity is a multifactorial disorder often associated with many important diseases such as diabetes, hypertension and other metabolic syndrome conditions. Argyrophil cells represent almost the total population of endocrine cells of the human gastric mucosa and some reports have described changes of specific types of these cells in patients with obesity and metabolic syndrome. The present study was designed to evaluate the global population of argyrophil cells of the gastric mucosa of morbidly obese and dyspeptic non-obese patients. Gastric biopsies of antropyloric and oxyntic mucosa were obtained from 50 morbidly obese patients (BMI >40) and 50 non-obese patients (17 dyspeptic overweight and 33 lean individuals) and processed for histology and Grimelius staining for argyrophil cell demonstration. Argyrophil cell density in the oxyntic mucosa of morbidly obese patients was higher in female (238.68 ± 83.71 cells/mm{sup 2}) than in male patients (179.31 ± 85.96 cells/mm{sup 2}) and also higher in female (214.20 ± 50.38 cells/mm{sup 2}) than in male (141.90 ± 61.22 cells/mm{sup 2}) morbidly obese patients with metabolic syndrome (P = 0.01 and P = 0.02, respectively). In antropyloric mucosa, the main difference in argyrophil cell density was observed between female morbidly obese patients with (167.00 ± 69.30 cells/mm{sup 2}) and without (234.00 ± 69.54 cells/mm{sup 2}) metabolic syndrome (P = 0.001). In conclusion, the present results show that the number of gastric argyrophil cells could be under gender influence in patients with morbid obesity. In addition, gastric argyrophil cells seem to behave differently among female morbidly obese patients with and without metabolic syndrome.

  14. Argyrophil cell density in the oxyntic mucosa is higher in female than in male morbidly obese patients

    Directory of Open Access Journals (Sweden)

    F.A.N. Maksud

    2013-05-01

    Full Text Available Obesity is a multifactorial disorder often associated with many important diseases such as diabetes, hypertension and other metabolic syndrome conditions. Argyrophil cells represent almost the total population of endocrine cells of the human gastric mucosa and some reports have described changes of specific types of these cells in patients with obesity and metabolic syndrome. The present study was designed to evaluate the global population of argyrophil cells of the gastric mucosa of morbidly obese and dyspeptic non-obese patients. Gastric biopsies of antropyloric and oxyntic mucosa were obtained from 50 morbidly obese patients (BMI >40 and 50 non-obese patients (17 dyspeptic overweight and 33 lean individuals and processed for histology and Grimelius staining for argyrophil cell demonstration. Argyrophil cell density in the oxyntic mucosa of morbidly obese patients was higher in female (238.68 ± 83.71 cells/mm2 than in male patients (179.31 ± 85.96 cells/mm2 and also higher in female (214.20 ± 50.38 cells/mm2 than in male (141.90 ± 61.22 cells/mm2 morbidly obese patients with metabolic syndrome (P = 0.01 and P = 0.02, respectively. In antropyloric mucosa, the main difference in argyrophil cell density was observed between female morbidly obese patients with (167.00 ± 69.30 cells/mm2 and without (234.00 ± 69.54 cells/mm2 metabolic syndrome (P = 0.001. In conclusion, the present results show that the number of gastric argyrophil cells could be under gender influence in patients with morbid obesity. In addition, gastric argyrophil cells seem to behave differently among female morbidly obese patients with and without metabolic syndrome.

  15. Argyrophil cell density in the oxyntic mucosa is higher in female than in male morbidly obese patients

    International Nuclear Information System (INIS)

    Obesity is a multifactorial disorder often associated with many important diseases such as diabetes, hypertension and other metabolic syndrome conditions. Argyrophil cells represent almost the total population of endocrine cells of the human gastric mucosa and some reports have described changes of specific types of these cells in patients with obesity and metabolic syndrome. The present study was designed to evaluate the global population of argyrophil cells of the gastric mucosa of morbidly obese and dyspeptic non-obese patients. Gastric biopsies of antropyloric and oxyntic mucosa were obtained from 50 morbidly obese patients (BMI >40) and 50 non-obese patients (17 dyspeptic overweight and 33 lean individuals) and processed for histology and Grimelius staining for argyrophil cell demonstration. Argyrophil cell density in the oxyntic mucosa of morbidly obese patients was higher in female (238.68 ± 83.71 cells/mm2) than in male patients (179.31 ± 85.96 cells/mm2) and also higher in female (214.20 ± 50.38 cells/mm2) than in male (141.90 ± 61.22 cells/mm2) morbidly obese patients with metabolic syndrome (P = 0.01 and P = 0.02, respectively). In antropyloric mucosa, the main difference in argyrophil cell density was observed between female morbidly obese patients with (167.00 ± 69.30 cells/mm2) and without (234.00 ± 69.54 cells/mm2) metabolic syndrome (P = 0.001). In conclusion, the present results show that the number of gastric argyrophil cells could be under gender influence in patients with morbid obesity. In addition, gastric argyrophil cells seem to behave differently among female morbidly obese patients with and without metabolic syndrome

  16. Argyrophil cell density in the oxyntic mucosa is higher in female than in male morbidly obese patients

    Directory of Open Access Journals (Sweden)

    F.A.N. Maksud

    2013-04-01

    Full Text Available Obesity is a multifactorial disorder often associated with many important diseases such as diabetes, hypertension and other metabolic syndrome conditions. Argyrophil cells represent almost the total population of endocrine cells of the human gastric mucosa and some reports have described changes of specific types of these cells in patients with obesity and metabolic syndrome. The present study was designed to evaluate the global population of argyrophil cells of the gastric mucosa of morbidly obese and dyspeptic non-obese patients. Gastric biopsies of antropyloric and oxyntic mucosa were obtained from 50 morbidly obese patients (BMI >40 and 50 non-obese patients (17 dyspeptic overweight and 33 lean individuals and processed for histology and Grimelius staining for argyrophil cell demonstration. Argyrophil cell density in the oxyntic mucosa of morbidly obese patients was higher in female (238.68 ± 83.71 cells/mm2 than in male patients (179.31 ± 85.96 cells/mm2 and also higher in female (214.20 ± 50.38 cells/mm2 than in male (141.90 ± 61.22 cells/mm2 morbidly obese patients with metabolic syndrome (P = 0.01 and P = 0.02, respectively. In antropyloric mucosa, the main difference in argyrophil cell density was observed between female morbidly obese patients with (167.00 ± 69.30 cells/mm2 and without (234.00 ± 69.54 cells/mm2 metabolic syndrome (P = 0.001. In conclusion, the present results show that the number of gastric argyrophil cells could be under gender influence in patients with morbid obesity. In addition, gastric argyrophil cells seem to behave differently among female morbidly obese patients with and without metabolic syndrome.

  17. Increased Chromogranin A Cell Density in the Large Intestine of Patients with Irritable Bowel Syndrome after Receiving Dietary Guidance

    Directory of Open Access Journals (Sweden)

    Tarek Mazzawi

    2015-01-01

    Full Text Available The large intestine contains five types of endocrine cells that regulate its functions by sensing its luminal contents and releasing specific hormones. Chromogranin A (CgA is a common marker for the gastrointestinal endocrine cells, and it is abnormal in irritable bowel syndrome (IBS patients. Most IBS patients relate their symptoms to certain food elements. The present study investigated the effect of dietary guidance on the total endocrine cells of the large intestine as detected by CgA in 13 IBS patients. Thirteen control subjects were also included. Each patient received three sessions of dietary guidance. Colonoscopies were performed on controls and patients (at baseline and at 3–9 months after receiving guidance. Biopsy samples from the colon and rectum were immunostained for CgA and quantified by computerized image analysis. The densities of CgA cells in the total colon (mean ± SEM among the controls and the IBS patients before and after receiving dietary guidance were 83.3±10.1, 38.6±3.7, and 64.7±4.2 cells/mm2, respectively (P=0.0004, and were unchanged in the rectum. In conclusion, the increase in CgA cell density after receiving dietary guidance may reflect a change in the densities of the large intestinal endocrine cells causing an improvement in the IBS symptoms.

  18. Lipid droplets characterization in adipocyte differentiated 3T3-L1 cells: size and optical density distribution

    Directory of Open Access Journals (Sweden)

    V. Rizzatti

    2013-08-01

    Full Text Available The 3T3-L1 cell line, derived from 3T3 cells, is widely used in biological research on adipose tissue. 3T3-L1 cells have a fibroblast-like morphology, but, under appropriate conditions, they differentiate into an adipocyte-like phenotype. During the differentiation process, 3T3-L1 cells increase the synthesis of triglycerides and acquire the behavior of adipose cells. In particular, triglycerides accumulate in lipid droplets (LDs embedded in the cytoplasm. The number and the size distribution of the LDs is often correlated with obesity and many other pathologies linked with fat accumulation. The integrated optical density (IOD of the LDs is related with the amount of triglycerides in the droplets. The aim of this study is the attempt to characterize the size distribution and the IOD of the LDs in 3T3-L1 differentiated cells. The cells were differentiated into adipocytes for 5 days with a standard procedure, stained with Oil Red O and observed with an optical microscope. The diameter, area, optical density of the LDs were measured. We found an asymmetry of the kernel density distribution of the maximum Feret’s diameter of the LDs with a tail due to very large LDs. More information regarding the birth of the LDs could help in finding the best mathematical model in order to analyze fat accumulation in adipocytes.

  19. Improving evaluation of the distribution and density of immunostained cells in breast cancer using computerized video image analysis

    International Nuclear Information System (INIS)

    Quantitation of cell density in tissues has proven problematic over the years. The manual microscopic methodology, where an investigator visually samples multiple areas within slides of tissue sections, has long remained the basic ‘standard’ for many studies and for routine histopathologic reporting. Nevertheless, novel techniques that may provide a more standardized approach to quantitation of cells in tissue sections have been made possible by computerized video image analysis methods over recent years. The present study describes a novel, computer-assisted video image analysis method of quantitating immunostained cells within tissue sections, providing continuous graphical data. This technique enables the measurement of both distribution and density of cells within tissue sections. Specifically, the study considered immunoperoxidase-stained tumor infiltrating lymphocytes within breast tumor specimens, using the number of immunostained pixels within tissue sections to determine cellular density and number. Comparison was made between standard manual graded quantitation methods and video image analysis, using the same tissue sections. The study demonstrates that video image techniques and computer analysis can provide continuous data on cell density and number in immunostained tissue sections, which compares favorably with standard visual quantitation methods, and may offer an alternative

  20. Paracrine effects and heterogeneity of marrow-derived stem/progenitor cells: relevance for the treatment of respiratory diseases.

    Science.gov (United States)

    Conese, Massimo; Carbone, Annalucia; Castellani, Stefano; Di Gioia, Sante

    2013-01-01

    Stem cell-based treatment may represent a hope for the treatment of acute lung injury and pulmonary fibrosis, and other chronic lung diseases, such as cystic fibrosis, asthma and chronic obstructive pulmonary disease (COPD). It is well established in preclinical models that bone marrow-derived stem and progenitor cells exert beneficial effects on inflammation, immune responses and repairing of damage in virtually all lung-borne diseases. While it was initially thought that the positive outcome was due to a direct engraftment of these cells into the lung as endothelial and epithelial cells, paracrine factors are now considered the main mechanism through which stem and progenitor cells exert their therapeutic effect. This knowledge has led to the clinical use of marrow cells in pulmonary hypertension with endothelial progenitor cells (EPCs) and in COPD with mesenchymal stromal (stem) cells (MSCs). Bone marrow-derived stem cells, including hematopoietic stem/progenitor cells, MSCs, EPCs and fibrocytes, encompass a wide array of cell subsets with different capacities of engraftment and injured tissue-regenerating potential. The characterization/isolation of the stem cell subpopulations represents a major challenge to improve the efficacy of transplantation protocols used in regenerative medicine and applied to lung disorders. PMID:23652321

  1. Experimental investigation of dynamic responses of a transparent PEM fuel cell to step changes in cell current density with operating temperature

    International Nuclear Information System (INIS)

    The dynamic responses of a proton exchange membrane fuel cell (PEMFC) are closely related to the novel water management technique used for the efficient operation of automotive PEMFCs. In order to better understand the dynamic water transport during cell transients, this paper presents an experimental investigation of the transient response of a cell under fully humidified conditions. The cell dynamic performance was measured by employing a transparent cell and investigated with visualization images of the water distribution in the flow channels. Furthermore, the effect of the operating temperature on the cell transients was examined. The results show that the cell dynamic behavior for the tested operating temperature (30-50 .deg. C) conditions is mainly governed by water transport characteristics related to cathode flooding. Also, we show that the time needed for the cell to reach steady-state after a current density step increase is retarded due to excessive water accumulation inside the cell at lower operating temperatures

  2. Electron density profile at the interfaces of bulk heterojunction solar cells and its implication on the S-kink characteristics

    Science.gov (United States)

    Gusain, Abhay; Singh, Surendra; Chauhan, A. K.; Saxena, Vibha; Jha, P.; Veerender, P.; Singh, Ajay; Varde, P. V.; Basu, Saibal; Aswal, D. K.; Gupta, S. K.

    2016-02-01

    The efficiency of a bulk heterojunction (BHJ) solar cell critically depends upon quality of its interfaces. The imperfect interfaces can lead to S-kink in the current-voltage characteristics that reduce the efficiency of BHJ solar cells. In this letter, using PCDTBT:PCBM based BHJ solar cells, we demonstrate that non-destructive X-ray reflectivity is powerful technique to estimate the electron density profile across the BHJ solar cells. A direct correlation is observed between the enhanced electron density at PEDOT:PSS/PCDTBT:PCBM interface and appearance of S-kink in J-V characteristics, which is also supported by X-ray photoelectron spectroscopy and Kelvin probe measurements.

  3. PORTSMOUTH ON-SITE DISPOSAL CELL HIGH DENSITY POLYETHYLENE GEOMEMBRANE LONGEVITY

    Energy Technology Data Exchange (ETDEWEB)

    Phifer, M.

    2012-01-31

    It is anticipated that high density polyethylene (HDPE) geomembranes will be utilized within the liner and closure cap of the proposed On-Site Disposal Cell (OSDC) at the Portsmouth Gaseous Diffusion Plant. The likely longevity (i.e. service life) of HDPE geomembranes in OSDC service is evaluated within the following sections of this report: (1) Section 2.0 provides an overview of HDPE geomembranes, (2) Section 3.0 outlines potential HDPE geomembranes degradation mechanisms, (3) Section 4.0 evaluates the applicability of HDPE geomembrane degradation mechanisms to the Portsmouth OSDC, (4) Section 5.0 provides a discussion of the current state of knowledge relative to the longevity (service life) of HDPE geomembranes, including the relation of this knowledge to the Portsmouth OSDC, and (5) Section 6.0 provides summary and conclusions relative to the anticipated service life of HDPE geomembranes in OSDC service. Based upon this evaluation it is anticipated that the service life of HDPE geomembranes in OSDC service would be significantly greater than the 200 year service life assumed for the OSDC closure cap and liner HDPE geomembranes. That is, a 200 year OSDC HDPE geomembrane service life is considered a conservative assumption.

  4. Model Assembly for Estimating Cell Surviving Fraction for Both Targeted and Nontargeted Effects Based on Microdosimetric Probability Densities

    OpenAIRE

    Sato, Tatsuhiko; Hamada, Nobuyuki

    2014-01-01

    We here propose a new model assembly for estimating the surviving fraction of cells irradiated with various types of ionizing radiation, considering both targeted and nontargeted effects in the same framework. The probability densities of specific energies in two scales, which are the cell nucleus and its substructure called a domain, were employed as the physical index for characterizing the radiation fields. In the model assembly, our previously established double stochastic microdosimetric...

  5. C-Reactive Protein-Bound Enzymatically Modified Low-Density Lipoprotein Does Not Transform Macrophages into Foam Cells1

    OpenAIRE

    Singh, Sanjay K.; Suresh, Madathilparambil V.; Prayther, Deborah C; Moorman, Jonathan P.; Rusiñol, Antonio E.; Agrawal, Alok

    2008-01-01

    The formation of low-density lipoprotein (LDL) cholesterol-loaded macrophage foam cells contributes to the development of atherosclerosis. C-reactive protein (CRP) binds to atherogenic forms of LDL, but the role of CRP in foam cell formation is unclear. In this study, we first explored the binding site on CRP for enzymatically modified LDL (E-LDL), a model of atherogenic LDL to which CRP binds. As reported previously, phosphocholine (PCh) inhibited CRP-E-LDL interaction, indicating the involv...

  6. The Effect of Amino Density on the Attachment, Migration, and Differentiation of Rat Neural Stem Cells In Vitro

    OpenAIRE

    Li, Hai-Long; Zhang, Han; Huang, Hua; Liu, Zhen-Qiang; Li, Yan-Bing; Yu, Hao(Institute of Theoretical Physics, Lanzhou University, 730000, Lanzhou, People’s Republic of China); An, Yi-Hua

    2013-01-01

    Artificial extracellular matrices play important roles in the regulation of stem cell behavior. To generate materials for tissue engineering, active functional groups, such as amino, carboxyl, and hydroxyl, are often introduced to change the properties of the biomaterial surface. In this study, we chemically modified coverslips to create surfaces with different amino densities and investigated the adhesion, migration, and differentiation of neural stem cells (NSCs) under serum-free culture co...

  7. Magnetic levitation of single cells.

    Science.gov (United States)

    Durmus, Naside Gozde; Tekin, H Cumhur; Guven, Sinan; Sridhar, Kaushik; Arslan Yildiz, Ahu; Calibasi, Gizem; Ghiran, Ionita; Davis, Ronald W; Steinmetz, Lars M; Demirci, Utkan

    2015-07-14

    Several cellular events cause permanent or transient changes in inherent magnetic and density properties of cells. Characterizing these changes in cell populations is crucial to understand cellular heterogeneity in cancer, immune response, infectious diseases, drug resistance, and evolution. Although magnetic levitation has previously been used for macroscale objects, its use in life sciences has been hindered by the inability to levitate microscale objects and by the toxicity of metal salts previously applied for levitation. Here, we use magnetic levitation principles for biological characterization and monitoring of cells and cellular events. We demonstrate that each cell type (i.e., cancer, blood, bacteria, and yeast) has a characteristic levitation profile, which we distinguish at an unprecedented resolution of 1 × 10(-4) g ⋅ mL(-1). We have identified unique differences in levitation and density blueprints between breast, esophageal, colorectal, and nonsmall cell lung cancer cell lines, as well as heterogeneity within these seemingly homogenous cell populations. Furthermore, we demonstrate that changes in cellular density and levitation profiles can be monitored in real time at single-cell resolution, allowing quantification of heterogeneous temporal responses of each cell to environmental stressors. These data establish density as a powerful biomarker for investigating living systems and their responses. Thereby, our method enables rapid, density-based imaging and profiling of single cells with intriguing applications, such as label-free identification and monitoring of heterogeneous biological changes under various physiological conditions, including antibiotic or cancer treatment in personalized medicine. PMID:26124131

  8. Heterogeneous detection of circulating tumor cells in patients with colorectal cancer by immunomagnetic enrichment using different EpCAM-specific antibodies

    Directory of Open Access Journals (Sweden)

    Büchler Markus W

    2010-04-01

    Full Text Available Abstract Background Circulating tumor cells (CTC and disseminated tumor cells (DTC are thought to be responsible for metastasis, so the detection of CTC may serve as individual prognostic factor in patients suffering from colorectal cancer. Therefore, a series of immunomagnetic enrichment methods for CTC have been developed using a variety of monoclonal antibodies against the Epithelial Cell Adhesion Molecule (EpCAM. However, it remains unclear whether all commercially available EpCAM antibodies show the same sensitivity and specificity. Furthermore, it remains unclear which method of sample preparation and cell extraction is most suitable for immunomagnetic enrichment and detection of CTC. In this study, we aimed to investigate whether the detection of CTC by a cytokeratin 20 reverse transcriptase-polymerase chain reaction (CK20 RT-PCR may be influenced by the use of various Epithelial Cell Adhesion Molecule (EpCAM antibodies for immunomagnetic isolation of CTC. Results Using both EpCAM antibodies (mAb BerEP4 and mAb KS1/4 for immunomagnetic enrichment in blood samples of 39 patients with colorectal cancer we found heterogenous results in each patient with regard to tumor cell detection. In the tumor cell spiking experiments with whole blood samples the sensitivity of the CK 20 RT-PCR assay was higher using immunomagnetic beads coated with mAb KS1/4 compared to precoated mAb BerEP4 Dynabeads. Extraction of MNC fraction with Ficoll gradient centrifugation prior to immunomagnetic enrichment resulted in a higher sensitivity of the CK 20 RT-PCR assay. Conclusions We concluded that isolation and detection of CTC with immunomagnetic enrichment methods is critically dependent on the used EpCAM clone. Further studies with a larger number of patients should clarify if the enrichment protocol influences the prognostic value of the tumor cell detection protocol.

  9. Production of savinase and population viability of Bacillus clausii during high-cell-density fed-batch cultivations

    DEFF Research Database (Denmark)

    Christiansen, Torben; Michaelsen, S.; Wumpelmann, M.;

    2003-01-01

    The growth and product formation of a Savinase-producing Bacillus clausii were investigated in high-cell-density fed-batch cultivations with both linear and exponential feed profiles. The highest specific productivity of Savinase was observed shortly after the end of the initial batch phase for a...

  10. Production of savinase and population viability of Bacillus clausii during high-cell-density fed-batch cultivations

    DEFF Research Database (Denmark)

    Christiansen, Torben; Michaelsen, S.; Wumpelmann, M.; Nielsen, Jens

    2003-01-01

    The growth and product formation of a Savinase-producing Bacillus clausii were investigated in high-cell-density fed-batch cultivations with both linear and exponential feed profiles. The highest specific productivity of Savinase was observed shortly after the end of the initial batch phase for all...

  11. Hematopoietic and mesenchymal stem cells for the treatment of chronic respiratory diseases: role of plasticity and heterogeneity.

    Science.gov (United States)

    Conese, Massimo; Piro, Donatella; Carbone, Annalucia; Castellani, Stefano; Di Gioia, Sante

    2014-01-01

    Chronic lung diseases, such as cystic fibrosis (CF), asthma, and chronic obstructive pulmonary disease (COPD) are incurable and represent a very high social burden. Stem cell-based treatment may represent a hope for the cure of these diseases. In this paper, we revise the overall knowledge about the plasticity and engraftment of exogenous marrow-derived stem cells into the lung, as well as their usefulness in lung repair and therapy of chronic lung diseases. The lung is easily accessible and the pathophysiology of these diseases is characterized by injury, inflammation, and eventually by remodeling of the airways. Bone marrow-derived stem cells, including hematopoietic stem/progenitor cells (HSPCs) and mesenchymal stromal (stem) cells (MSCs), encompass a wide array of cell subsets with different capacities of engraftment and injured tissue regenerating potential. Proof-of-principle that marrow cells administered locally may engraft and give rise to specialized epithelial cells has been given, but the efficiency of this conversion is too limited to give a therapeutic effect. Besides the identification of plasticity mechanisms, the characterization/isolation of the stem cell subpopulations represents a major challenge to improving the efficacy of transplantation protocols used in regenerative medicine for lung diseases. PMID:24563632

  12. Hematopoietic and Mesenchymal Stem Cells for the Treatment of Chronic Respiratory Diseases: Role of Plasticity and Heterogeneity

    Directory of Open Access Journals (Sweden)

    Massimo Conese

    2014-01-01

    Full Text Available Chronic lung diseases, such as cystic fibrosis (CF, asthma, and chronic obstructive pulmonary disease (COPD are incurable and represent a very high social burden. Stem cell-based treatment may represent a hope for the cure of these diseases. In this paper, we revise the overall knowledge about the plasticity and engraftment of exogenous marrow-derived stem cells into the lung, as well as their usefulness in lung repair and therapy of chronic lung diseases. The lung is easily accessible and the pathophysiology of these diseases is characterized by injury, inflammation, and eventually by remodeling of the airways. Bone marrow-derived stem cells, including hematopoietic stem/progenitor cells (HSPCs and mesenchymal stromal (stem cells (MSCs, encompass a wide array of cell subsets with different capacities of engraftment and injured tissue regenerating potential. Proof-of-principle that marrow cells administered locally may engraft and give rise to specialized epithelial cells has been given, but the efficiency of this conversion is too limited to give a therapeutic effect. Besides the identification of plasticity mechanisms, the characterization/isolation of the stem cell subpopulations represents a major challenge to improving the efficacy of transplantation protocols used in regenerative medicine for lung diseases.

  13. Heterogeneity in 2-deoxy-D-glucose-induced modifications in energetics and radiation responses of human tumor cell lines

    International Nuclear Information System (INIS)

    Purpose: The glucose analog and glycolytic inhibitor, 2-deoxy-D-glucose (2-DG), has been shown to differentially enhance the radiation damage in tumor cells by inhibiting the postirradiation repair processes. The present study was undertaken to examine the relationship between 2-DG-induced modification of energy metabolism and cellular radioresponses and to identify the most relevant parameter(s) for predicting the tumor response to the combined treatment of radiation + 2-DG. Methods and Materials: Six human tumor cell lines (glioma: BMG-1 and U-87, squamous cell carcinoma: 4451 and 4197, and melanoma: MeWo and Be-11) were investigated. Cells were exposed to 2 Gy of Co-60 γ-rays or 250 kVP X-rays and maintained under liquid-holding conditions 2-4 h to facilitate repair. 2-DG (5 mM, equimolar with glucose) that was added at the time of irradiation was present during the liquid holding. Glucose utilization, lactate production (enzymatic assays), and adenine nucleotides (high performance liquid chromatography and capillary isotachophoresis) were investigated as parameters of energy metabolism. Induction and repair of DNA damage (comet assay), cytogenetic damage (micronuclei formation), and cell death (macrocolony assay) were analyzed as parameters of radiation response. Results: The glucose consumption and lactate production of glioma cell lines (BMG-1 and U-87) were nearly 2-fold higher than the squamous carcinoma cell lines (4197 and 4451). The ATP content varied from 3.0 to 6.5 femto moles/cell among these lines, whereas the energy charge (0.86-0.90) did not show much variation. Presence of 2-DG inhibited the rate of glucose usage and glycolysis by 30-40% in glioma cell lines and by 15-20% in squamous carcinoma lines, while ATP levels reduced by nearly 40% in all the four cell lines. ATP:ADP ratios decreased to a greater extent (∼40%) in glioma cells than in squamous carcinoma 4451 and MeWo cells; in contrast, presence of 2-DG reduced ADP:AMP ratios by 3-fold in

  14. Computational neuroanatomy: mapping cell-type densities in the mouse brain, simulations from the Allen Brain Atlas

    Science.gov (United States)

    Grange, Pascal

    2015-09-01

    The Allen Brain Atlas of the adult mouse (ABA) consists of digitized expression profiles of thousands of genes in the mouse brain, co-registered to a common three-dimensional template (the Allen Reference Atlas).This brain-wide, genome-wide data set has triggered a renaissance in neuroanatomy. Its voxelized version (with cubic voxels of side 200 microns) is available for desktop computation in MATLAB. On the other hand, brain cells exhibit a great phenotypic diversity (in terms of size, shape and electrophysiological activity), which has inspired the names of some well-studied cell types, such as granule cells and medium spiny neurons. However, no exhaustive taxonomy of brain cell is available. A genetic classification of brain cells is being undertaken, and some cell types have been chraracterized by their transcriptome profiles. However, given a cell type characterized by its transcriptome, it is not clear where else in the brain similar cells can be found. The ABA can been used to solve this region-specificity problem in a data-driven way: rewriting the brain-wide expression profiles of all genes in the atlas as a sum of cell-type-specific transcriptome profiles is equivalent to solving a quadratic optimization problem at each voxel in the brain. However, the estimated brain-wide densities of 64 cell types published recently were based on one series of co-registered coronal in situ hybridization (ISH) images per gene, whereas the online ABA contains several image series per gene, including sagittal ones. In the presented work, we simulate the variability of cell-type densities in a Monte Carlo way by repeatedly drawing a random image series for each gene and solving the optimization problem. This yields error bars on the region-specificity of cell types.

  15. A plant culture (BY-2) widely used in molecular and cell studies is genetically unstable and highly heterogeneous

    Czech Academy of Sciences Publication Activity Database

    Kovařík, Aleš; Lim, K. Y.; Součková Skalická, Kamila; Matyášek, Roman; Leitch, A. R.

    2012-01-01

    Roč. 170, č. 3 (2012), s. 459-471. ISSN 0024-4074 R&D Projects: GA ČR(CZ) GAP501/10/0208 Institutional support: RVO:68081707 Keywords : cell biology * cell cycle * evolution Subject RIV: BO - Biophysics Impact factor: 2.589, year: 2012

  16. Clonal heterogeneity of small-cell anaplastic carcinoma of the lung demonstrated by flow-cytometric DNA analysis

    DEFF Research Database (Denmark)

    Vindeløv, L L; Hansen, H H; Christensen, I J;

    1980-01-01

    Flow-cytometric DNA analysis yields information on ploidy and proliferative characteristics of a cell population. The analysis was implemented on small-cell anaplastic carcinoma of the lung using a rapid detergent technique for the preparation of fine-needle aspirates for DNA determination and a...... newly developed procedure for storing aspirates at -80 degrees. Thirty-eight different metastases in 30 consecutive patients with small-cell anaplastic carcinoma of the lung were examined with a total of 273 fine-needle aspirations. The results on ploidy are reported in this paper. The degree of...... contamination of the aspirates with normal cells was determined by differential counts. The ratio of the peak channel numbers for the G1 phase of the tumor cells to that of the diploid standard (DNA index) was calculated and used for ploidy identification. Twenty-nine patients were evaluable with respect to DNA...

  17. A High Power Density, High Efficiency Hydrogen-Chlorine Regenerative Fuel Cell with a Low Precious Metal Content Catalyst

    OpenAIRE

    Huskinson, Brian; Rugolo, Jason; Mondal, Sujit K.; Aziz, Michael J.

    2012-01-01

    We report the performance of a hydrogen-chlorine electrochemical cell with a chlorine electrode employing a low precious metal content alloy oxide electrocatalyst for the chlorine electrode: (Ru_0.09Co_0.91)_3O_4. The cell employs a commercial hydrogen fuel cell electrode and transports protons through a Nafion membrane in both galvanic and electrolytic mode. The peak galvanic power density exceeds 1 W cm^-2, which is twice previous literature values. The precious metal loading of the chlorin...

  18. Variation of carrier concentration and interface trap density in 8MeV electron irradiated c-Si solar cells

    International Nuclear Information System (INIS)

    The capacitance and conductance measurements were carried out for c-Si solar cells, irradiated with 8 MeV electrons with doses ranging from 5kGy – 100kGy in order to investigate the anomalous degradation of the cells in the radiation harsh environments. Capacitance – Voltage measurements indicate that there is a slight reduction in the carrier concentration upon electron irradiation due to the creation of radiation induced defects. The conductance measurement results reveal that the interface state densities and the trap time constant increases with electron dose due to displacement damages in c-Si solar cells

  19. Three-dimensional printing of stem cell-laden hydrogels submerged in a hydrophobic high-density fluid

    International Nuclear Information System (INIS)

    Over the last decade, bioprinting technologies have begun providing important tissue engineering strategies for regenerative medicine and organ transplantation. The major drawback of past approaches has been poor or inadequate material-printing device and substrate combinations, as well as the relatively small size of the printed construct. Here, we hypothesise that cell-laden hydrogels can be printed when submerged in perfluorotributylamine (C12F27N), a hydrophobic high-density fluid, and that these cells placed within three-dimensional constructs remain viable allowing for cell proliferation and production of extracellular matrix. Human mesenchymal stem cells and MG-63 cells were encapsulated into agarose hydrogels, and subsequently printed in high aspect ratio in three dimensional structures that were supported in high density fluorocarbon. Three-dimensional structures with various shapes and sizes were manufactured and remained stable for more than six months. Live/dead and DAPI stainings showed viable cells 24 h after the printing process, as well as after 21 days in culture. Histological and immunohistochemical analyses after 14 and 21 days revealed viable cells with marked matrix production and signs of proliferation. The compressive strength values of the printed gels consequently increased during the two weeks in culture, revealing encouraging results for future applications in regenerative medicine. (paper)

  20. A glycosaminoglycan based, modular tissue scaffold system for rapid assembly of perfusable, high cell density, engineered tissues.

    Directory of Open Access Journals (Sweden)

    Ramkumar Tiruvannamalai-Annamalai

    Full Text Available The limited ability to vascularize and perfuse thick, cell-laden tissue constructs has hindered efforts to engineer complex tissues and organs, including liver, heart and kidney. The emerging field of modular tissue engineering aims to address this limitation by fabricating constructs from the bottom up, with the objective of recreating native tissue architecture and promoting extensive vascularization. In this paper, we report the elements of a simple yet efficient method for fabricating vascularized tissue constructs by fusing biodegradable microcapsules with tunable interior environments. Parenchymal cells of various types, (i.e. trophoblasts, vascular smooth muscle cells, hepatocytes were suspended in glycosaminoglycan (GAG solutions (4%/1.5% chondroitin sulfate/carboxymethyl cellulose, or 1.5 wt% hyaluronan and encapsulated by forming chitosan-GAG polyelectrolyte complex membranes around droplets of the cell suspension. The interior capsule environment could be further tuned by blending collagen with or suspending microcarriers in the GAG solution These capsule modules were seeded externally with vascular endothelial cells (VEC, and subsequently fused into tissue constructs possessing VEC-lined, inter-capsule channels. The microcapsules supported high density growth achieving clinically significant cell densities. Fusion of the endothelialized, capsules generated three dimensional constructs with an embedded network of interconnected channels that enabled long-term perfusion culture of the construct. A prototype, engineered liver tissue, formed by fusion of hepatocyte-containing capsules exhibited urea synthesis rates and albumin synthesis rates comparable to standard collagen sandwich hepatocyte cultures. The capsule based, modular approach described here has the potential to allow rapid assembly of tissue constructs with clinically significant cell densities, uniform cell distribution, and endothelialized, perfusable channels.

  1. Disordered hyperuniform heterogeneous materials.

    Science.gov (United States)

    Torquato, Salvatore

    2016-10-19

    Disordered hyperuniform many-body systems are distinguishable states of matter that lie between a crystal and liquid: they are like perfect crystals in the way they suppress large-scale density fluctuations and yet are like liquids or glasses in that they are statistically isotropic with no Bragg peaks. These systems play a vital role in a number of fundamental and applied problems: glass formation, jamming, rigidity, photonic and electronic band structure, localization of waves and excitations, self-organization, fluid dynamics, quantum systems, and pure mathematics. Much of what we know theoretically about disordered hyperuniform states of matter involves many-particle systems. In this paper, we derive new rigorous criteria that disordered hyperuniform two-phase heterogeneous materials must obey and explore their consequences. Two-phase heterogeneous media are ubiquitous; examples include composites and porous media, biological media, foams, polymer blends, granular media, cellular solids, and colloids. We begin by obtaining some results that apply to hyperuniform two-phase media in which one phase is a sphere packing in d-dimensional Euclidean space [Formula: see text]. Among other results, we rigorously establish the requirements for packings of spheres of different sizes to be 'multihyperuniform'. We then consider hyperuniformity for general two-phase media in [Formula: see text]. Here we apply realizability conditions for an autocovariance function and its associated spectral density of a two-phase medium, and then incorporate hyperuniformity as a constraint in order to derive new conditions. We show that some functional forms can immediately be eliminated from consideration and identify other forms that are allowable. Specific examples and counterexamples are described. Contact is made with well-known microstructural models (e.g. overlapping spheres and checkerboards) as well as irregular phase-separation and Turing-type patterns. We also ascertain a family

  2. SPIB and BATF provide alternate determinants of IRF4 occupancy in diffuse large B-cell lymphoma linked to disease heterogeneity.

    Science.gov (United States)

    Care, Matthew A; Cocco, Mario; Laye, Jon P; Barnes, Nicholas; Huang, Yuanxue; Wang, Ming; Barrans, Sharon; Du, Ming; Jack, Andrew; Westhead, David R; Doody, Gina M; Tooze, Reuben M

    2014-07-01

    Interferon regulatory factor 4 (IRF4) is central to the transcriptional network of activated B-cell-like diffuse large B-cell lymphoma (ABC-DLBCL), an aggressive lymphoma subgroup defined by gene expression profiling. Since cofactor association modifies transcriptional regulatory input by IRF4, we assessed genome occupancy by IRF4 and endogenous cofactors in ABC-DLBCL cell lines. IRF4 partners with SPIB, PU.1 and BATF genome-wide, but SPIB provides the dominant IRF4 partner in this context. Upon SPIB knockdown IRF4 occupancy is depleted and neither PU.1 nor BATF acutely compensates. Integration with ENCODE data from lymphoblastoid cell line GM12878, demonstrates that IRF4 adopts either SPIB- or BATF-centric genome-wide distributions in related states of post-germinal centre B-cell transformation. In primary DLBCL high-SPIB and low-BATF or the reciprocal low-SPIB and high-BATF mRNA expression links to differential gene expression profiles across nine data sets, identifying distinct associations with SPIB occupancy, signatures of B-cell differentiation stage and potential pathogenetic mechanisms. In a population-based patient cohort, SPIBhigh/BATFlow-ABC-DLBCL is enriched for mutation of MYD88, and SPIBhigh/BATFlow-ABC-DLBCL with MYD88-L265P mutation identifies a small subgroup of patients among this otherwise aggressive disease subgroup with distinct favourable outcome. We conclude that differential expression of IRF4 cofactors SPIB and BATF identifies biologically and clinically significant heterogeneity among ABC-DLBCL. PMID:24875472

  3. Short-circuit current density imaging of crystalline silicon solar cells via lock-in thermography: Robustness and simplifications

    International Nuclear Information System (INIS)

    Spatially resolved determination of solar cell parameters is beneficial for loss analysis and optimization of conversion efficiency. One key parameter that has been challenging to access by an imaging technique on solar cell level is short-circuit current density. This work discusses the robustness of a recently suggested approach to determine short-circuit current density spatially resolved based on a series of lock-in thermography images and options for a simplified image acquisition procedure. For an accurate result, one or two emissivity-corrected illuminated lock-in thermography images and one dark lock-in thermography image have to be recorded. The dark lock-in thermography image can be omitted if local shunts are negligible. Furthermore, it is shown that omitting the correction of lock-in thermography images for local emissivity variations only leads to minor distortions for standard silicon solar cells. Hence, adequate acquisition of one image only is sufficient to generate a meaningful map of short-circuit current density. Beyond that, this work illustrates the underlying physics of the recently proposed method and demonstrates its robustness concerning varying excitation conditions and locally increased series resistance. Experimentally gained short-circuit current density images are validated for monochromatic illumination in comparison to the reference method of light-beam induced current

  4. A Breast Cell Atlas: Organelle analysis of the MDA-MB-231 cell line by density-gradient fractionation using isotopic marking and label-free analysis

    Directory of Open Access Journals (Sweden)

    Marianne Sandin

    2015-09-01

    Full Text Available Protein translocation between organelles in the cell is an important process that regulates many cellular functions. However, organelles can rarely be isolated to purity so several methods have been developed to analyse the fractions obtained by density gradient centrifugation. We present an analysis of the distribution of proteins amongst organelles in the human breast cell line, MDA-MB-231 using two approaches: an isotopic labelling and a label-free approach.

  5. Modeling heterogeneity in the pluripotent state: A promising strategy for improving the efficiency and fidelity of stem cell differentiation.

    Science.gov (United States)

    Espinosa Angarica, Vladimir; Del Sol, Antonio

    2016-08-01

    Pluripotency can be considered a functional characteristic of pluripotent stem cells (PSCs) populations and their niches, rather than a property of individual cells. In this view, individual cells within the population independently adopt a variety of different expression states, maintained by different signaling, transcriptional, and epigenetics regulatory networks. In this review, we propose that generation of integrative network models from single cell data will be essential for getting a better understanding of the regulation of self-renewal and differentiation. In particular, we suggest that the identification of network stability determinants in these integrative models will provide important insights into the mechanisms mediating the transduction of signals from the niche, and how these signals can trigger differentiation. In this regard, the differential use of these stability determinants in subpopulation-specific regulatory networks would mediate differentiation into different cell fates. We suggest that this approach could offer a promising avenue for the development of novel strategies for increasing the efficiency and fidelity of differentiation, which could have a strong impact on regenerative medicine. PMID:27321053

  6. Tissue heterogeneity in structure and conductivity contribute to cell survival during irreversible electroporation ablation by ``electric field sinks''

    Science.gov (United States)

    Golberg, Alexander; Bruinsma, Bote G.; Uygun, Basak E.; Yarmush, Martin L.

    2015-02-01

    Irreversible electroporation (IRE) is an emerging, minimally invasive technique for solid tumors ablation, under clinical investigation for cancer therapy. IRE affects only the cell membrane, killing cells while preserving the extracellular matrix structure. Current reports indicate tumors recurrence rate after IRE averaging 31% of the cases, of which 10% are local recurrences. The mechanisms for these recurrences are not known and new explanations for incomplete cell death are needed. Using finite elements method for electric field distribution, we show that presence of vascular structures with blood leads to the redistribution of electric fields leading to the areas with more than 60% reduced electric field strength in proximity to large blood vessels and clustered vessel structures. In an in vivo rat model of liver IRE ablation, we show that cells located in the proximity of larger vessel structures and in proximity of clustered vessel structures appear less affected by IRE ablation than cells in the tissue parenchyma or in the proximity of small, more isolated vessels. These findings suggest a role for ``electric field sinks'' in local tumors recurrences after IRE and emphasize the importance of the precise mapping of the targeted organ structure and conductivity for planning of electroporation procedures.

  7. Association among heterogeneity of intratumoral anti-CD20 antibody distribution, glucose metabolism and therapeutic response in radioimmunotherapy for B-cell lymphoma

    International Nuclear Information System (INIS)

    Full text of publication follows. Aim: in Zevalin therapy for CD20 positive low-grade lymphoma, heterogeneity of intratumoral anti-CD20 antibody distribution as well as status of lesional glucose metabolism prior to therapy may affect tumor response. The aim of this study was to evaluate association of heterogeneity of intratumoral In-111 Zevalin (In-Zevalin), accumulation of F-18 FDG (FDG), and therapeutic response in patients receiving Zevalin therapy. Methods: 16 patients with CD20 positive B-cell non-Hodgkin's lymphoma who underwent Y-90 Zevalin therapy after imaging with In-Zevalin SPECT/CT and FDG PET/CT were enrolled. Patients received In-Zevalin, followed by SPECT/CT scanning at 48 hours after administration. SUVmax of FDG of lesions was measured on PET/CT while lesion accumulation of In-Zevalin as %ID/g and SUVmax of In-Zevalin (In-Zevalin SUVmax) was measured on SPECT/CT. To evaluate heterogeneity of anti-CD20 antibody distribution, skewness and kurtosis of voxel distribution were calculated by placing there-dimensional volumes of interest (3-D VOIs) on SPECT/CT images. As another intratumoral heterogeneity index, cumulative SUVmax-volume histograms describing percentage of total tumor volume above thresholds of In-Zevalin SUVmax (AUC-CSH) were calculated by placing 3-D VOIs. All lesions (n=42) were classified into responders and non-responders lesion-by-lesion on pre- and post-therapeutic CT images. Results: by lesion-based analysis, a positive correlation was observed between FDG SUVmax and accumulation of In-Zevalin. Accumulation of In-Zevalin was 0.0022 ± 0.0009 and 0.0024 ± 0.0008 %ID/g (n.s.), and 2.74 ± 1.43 and 3.29 ± 1.47 SUVmax (n.s.) for responders and non-responders, respectively. In contrast, voxel distribution of In-Zevalin demonstrated skewness of 0.58 ± 0.16 and 0.73 ± 0.24 (p<0.05), kurtosis of 2.39 ± 0.32 and 2.78 ± 0.53 (p<0.02), and AUC-CSH of 0.37 ± 0.04 and 0.34 ± 0.05 (p<0.05) for responders and non

  8. Heterogeneity and Microeconometrics Modelling

    DEFF Research Database (Denmark)

    Browning, Martin; Carro, Jesus

    Presented at the 2005 Econometric Society World Congress Plenary Session on "Modelling Heterogeneity". We survey the treatment of heterogeneity in applied microeconometrics analyses. There are three themes. First, there is usually much more heterogeneity than empirical researchers allow for. Seco...... structures. The latter task is one for economists: "heterogeneity is too important to be left to the statisticians". The paper concludes with a report of our own research on dynamic discrete choice models that allow for maximal heterogeneity...

  9. Genotype-phenotype heterogeneity of ganglion cell and inner plexiform layer deficit in autosomal-dominant optic atrophy

    DEFF Research Database (Denmark)

    Rönnbäck, Cecilia; Nissen, Claus; Almind, Gitte J; Grønskov, Karen; Milea, Dan; Larsen, Michael

    2015-01-01

    PURPOSE: To describe the thickness of the combined ganglion cell and inner plexiform layers (GC-IPL) and the peripapillary retinal nerve fibre layer (RNFL) in patients with OPA1 c.983A>G or c.2708_2711delTTAG autosomal-dominant optic atrophy (ADOA). METHODS: The study included 20 individuals with c...

  10. Pneumatic-aided micro-molding for flexible fabrication of homogeneous and heterogeneous cell-laden microgels.

    Science.gov (United States)

    Ma, Chao; Tian, Chang; Zhao, Lei; Wang, Jinyi

    2016-07-01

    Microgels are favorable for numerous applications such as drug delivery, biomaterials science and tissue engineering. Conventionally, photolithographic methods and micro-molding techniques are extensively exploited to prepare microgels; however, they are, respectively, limited to photocrosslinkable polymers and inadequate to generate serially patterned hydrogels due to the static nature of utilized molds. Herein, we proposed a simple and versatile approach, termed pneumatic-aided micro-molding (PAM), to flexibly fabricate microgels with precise control over multiple cell types and microarchitectures of hydrogels through strategically designed pneumatic microvalves. Using the PAM approach, different cells were encapsulated in various hydrogels that had well-defined geometries. Additionally, single/multiple micro-channeled cell-laden microgels were fabricated, of which the shape, number and arrangement could be finely tuned by varying microvalve configurations. Moreover, multi-compartmental microgels comprising composite hydrogel structures were engineered following a two-step PAM, which demonstrated the utility for biomimetically constructing a three-dimensional (3D) liver microtissue composed of a radially orchestrated network of hepatic cords and sinusoids. The resulting microtissue resembled the organizational complexity of the liver lobule and was applied for the evaluation of acetaminophen-induced hepatotoxicity. Collectively, the PAM strategy could be a useful and powerful tool in biomedical engineering, in vitro 3D cell culture, and fundamental biological studies. PMID:27229899

  11. Nanomodification of the electrodes in microbial fuel cell: impact of nanoparticle density on electricity production and microbial community

    DEFF Research Database (Denmark)

    Al Atraktchi, Fatima Al-Zahraa; Zhang, Yifeng; Angelidaki, Irini

    2014-01-01

    The nano-decoration of electrode with nanoparticles is one effective way to enhance power output of microbial fuel cells (MFCs). However, the amount of nanoparticles used for decoration has not been optimized yet, and how it affects the microbial community is still unknown. In this study, different......, respectively, which was 1.22-1.88 times higher than that obtained with plain carbon paper electrode (control). Furthermore, the Coulombic efficiency was increased with the Au density. Consequently, the maximum lag time before stable power generation was shortened by 1.22 times the lag time of the control....... Different densities of Au nanoparticles also resulted in different microbial communities on the anode. More diverse bacterial communities were found with higher Au nanoparticle densities. These results provide new dimensions in understanding electrode modification with nanoparticles in MFC systems....

  12. Low Temperature, High Energy Density Micro Thin Film Solid Oxide Fuel Cell Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A new type of solid oxide fuel cell based on thin film technology and ultra-thin electrolyte is being proposed to develop to realize major reductions in fuel cell...

  13. Mechanical Stimulation in Preventing Bone Density Loss in Patients Undergoing Donor Stem Cell Transplant

    Science.gov (United States)

    2012-07-05

    Accelerated Phase Chronic Myelogenous Leukemia; Adult Acute Lymphoblastic Leukemia in Remission; Adult Acute Myeloid Leukemia in Remission; Adult Acute Myeloid Leukemia With 11q23 (MLL) Abnormalities; Adult Acute Myeloid Leukemia With Del(5q); Adult Acute Myeloid Leukemia With Inv(16)(p13;q22); Adult Acute Myeloid Leukemia With t(15;17)(q22;q12); Adult Acute Myeloid Leukemia With t(16;16)(p13;q22); Adult Acute Myeloid Leukemia With t(8;21)(q22;q22); Atypical Chronic Myeloid Leukemia, BCR-ABL1 Negative; Blastic Phase Chronic Myelogenous Leukemia; Chronic Eosinophilic Leukemia; Chronic Myelomonocytic Leukemia; Chronic Neutrophilic Leukemia; Chronic Phase Chronic Myelogenous Leukemia; de Novo Myelodysplastic Syndromes; Disseminated Neuroblastoma; Extranodal Marginal Zone B-cell Lymphoma of Mucosa-associated Lymphoid Tissue; Myelodysplastic/Myeloproliferative Neoplasm, Unclassifiable; Nodal Marginal Zone B-cell Lymphoma; Noncontiguous Stage II Adult Burkitt Lymphoma; Noncontiguous Stage II Adult Diffuse Large Cell Lymphoma; Noncontiguous Stage II Adult Diffuse Mixed Cell Lymphoma; Noncontiguous Stage II Adult Diffuse Small Cleaved Cell Lymphoma; Noncontiguous Stage II Adult Immunoblastic Large Cell Lymphoma; Noncontiguous Stage II Adult Lymphoblastic Lymphoma; Noncontiguous Stage II Grade 1 Follicular Lymphoma; Noncontiguous Stage II Grade 2 Follicular Lymphoma; Noncontiguous Stage II Grade 3 Follicular Lymphoma; Noncontiguous Stage II Mantle Cell Lymphoma; Noncontiguous Stage II Marginal Zone Lymphoma; Noncontiguous Stage II Small Lymphocytic Lymphoma; Plasma Cell Neoplasm; Poor Prognosis Metastatic Gestational Trophoblastic Tumor; Previously Treated Myelodysplastic Syndromes; Primary Myelofibrosis; Prolymphocytic Leukemia; Recurrent Adult Acute Lymphoblastic Leukemia; Recurrent Adult Acute Myeloid Leukemia; Recurrent Adult Burkitt Lymphoma; Recurrent Adult Diffuse Large Cell Lymphoma; Recurrent Adult Diffuse Mixed Cell Lymphoma; Recurrent Adult Diffuse Small Cleaved

  14. Early Change in Metabolic Tumor Heterogeneity during Chemoradiotherapy and Its Prognostic Value for Patients with Locally Advanced Non-Small Cell Lung Cancer.

    Directory of Open Access Journals (Sweden)

    Xinzhe Dong

    Full Text Available To observe the early change of metabolic tumor heterogeneity during chemoradiotherapy and to determine its prognostic value for patients with locally advanced non-small cell lung cancer (NSCLC.From January 2007 to March 2010, 58 patients with NSCLC were included who were received 18F-fluorodeoxyglucose (18F-FDG PET/CT before and following 40 Gy radiotherapy with the concurrent cisplatin-based chemotherapy (CCRT. Primary tumor FDG uptake heterogeneity was determined using global and local scale textural features extracted from standardized uptake value (SUV histogram analysis (coefficient of variation [COV], skewness, kurtosis, area under the curve of the cumulative SUV histogram [AUC-CSH] and normalized gray-level co-occurrence matrix (contrast, dissimilarity, entropy, homogeneity. SUVmax and metabolic tumor volume (MTV were also evaluated. Correlations were analyzed between parameters on baseline or during treatments with tumor response, progression-free survival (PFS, and overall survival (OS.Compared with non-responders, responders showed significantly greater pre-treatment COV, contrast and MTV (AUC = 0.781, 0.804, 0.686, respectively. Receiver-operating-characteristic curve analysis showed that early change of tumor textural analysis serves as a response predictor with higher sensitivity (73.2%~92.1% and specificity (80.0%~83.6% than baseline parameters. Change in AUC-CSH and dissimilarity during CCRT could also predict response with optimal cut-off values (33.0% and 28.7%, respectively. The patients with greater changes in contrast and AUC-CSH had significantly higher 5-year OS (P = 0.008, P = 0.034 and PFS (P = 0.007, P = 0.039. In multivariate analysis, only change in contrast was found as the independent prognostic factor of PFS (HR 0.476, P = 0.021 and OS (HR 0.519, P = 0.015.The metabolic tumor heterogeneity change during CCRT characterized by global and local scale textural features may be valuable for predicting treatment response

  15. Real-time viable-cell mass monitoring in high-cell-density fed-batch glutathione fermentation by Saccharomyces cerevisiae T65 in industrial complex medium.

    Science.gov (United States)

    Xiong, Zhi-Qiang; Guo, Mei-Jin; Guo, Yuan-Xin; Chu, Ju; Zhuang, Ying-Ping; Zhang, Si-Liang

    2008-04-01

    An on-line monitoring of viable-cell mass in high-cell-density fed-batch cultivations of Saccharomyces cerevisiae grown on an industrial complex medium was performed with an in situ capacitance probe fitted to a 50-l fermentor. Conventional off-line biomass determinations of several parameters, including dry cell weight (DCW), optical density at 600 nm wavelength (OD(600)), packed mycelial volume (PMV) and number of colony forming units (CFU), were performed throughout the bioprocess and then compared with on-line viable-cell concentrations measured using a capacitance probe. Capacitance versus viable biomass and all off-line biomass assay values were compared during glutathione fermentation in industrial complex culture media. As a result, the relationship between the number of colony forming units and capacitance with a correlation coefficient (R) of 0.995 was achieved. Simultaneously, compared with those determined by at-line indirect estimation methods including oxygen uptake rate (OUR) and carbon dioxide evolution rate (CER), the specific growth rates estimated by on-line capacitance measurement could be more reliable during glutathione fermentation. Therefore, it is concluded that a capacitance probe is a practical tool for real-time viable biomass monitoring in high-cell-density fed-batch cultivation in a complex medium. PMID:18499059

  16. Quantitative Carrier Density Wave Imaging in Silicon Solar Cells Using Photocarrier Radiometry and Lock-in Carrierography

    Science.gov (United States)

    Sun, Q. M.; Melnikov, A.; Mandelis, A.

    2016-04-01

    InGaAs camera-based low-frequency homodyne and high-frequency heterodyne lock-in carrierographies (LIC) are introduced for spatially resolved imaging of optoelectronic properties of Si solar cells. Based on the full theory of solar cell photocarrier radiometry (PCR), several simplification steps were performed aiming at the open circuit case, and a concise expression of the base minority carrier density depth profile was obtained. The model shows that solar cell PCR/LIC signals are mainly sensitive to the base minority carrier lifetime. Both homodyne and heterodyne frequency response data at selected locations on a mc-Si solar cell were used to extract the local base minority carrier lifetimes by best fitting local experimental data to theory.

  17. Characterization of endocytic compartments after holo-high density lipoprotein particle uptake in HepG2 cells

    OpenAIRE

    Röhrl, Clemens; Pagler, Tamara A.; Strobl, Witta; Ellinger, Adolf; Neumüller, Josef; Pavelka, Margit; Stangl, Herbert; Meisslitzer-Ruppitsch, Claudia

    2009-01-01

    Holo-high density lipoprotein (HDL) particle uptake, besides selective lipid uptake, constitutes an alternative pathway to regulate cellular cholesterol homeostasis. In the current study, the cellular path of holo-HDL particles was investigated in human liver carcinoma cells (HepG2) using combined light and electron microscopical methods. The apolipoprotein moiety of HDL was visualized with different markers: horseradish peroxidase, colloidal gold and the fluorochrome Alexa568, used in fluore...

  18. Application of high cell density airlift bioreactors to bio-ethanol production – study on optimal bioreactor operation

    OpenAIRE

    Klein, Jaroslav; Vicente, A.A.; Maia, J. M.; Domingues, Lucília; Teixeira, J.A.

    2004-01-01

    In this paper a hydrodynamic and rheological analysis of a continuous airlift bioreactor with high cell density system is presented. A highly flocculating recombinant strain of Sacharomyces cerevisae containing genes for lactose transport (lactose permease) and hydrolysis (β-galactosidase) was exploited to ferment lactose from cheese whey to ethanol. The magnetic particle-tracer method was used to assess the effect of operational conditions (air flow rate, biomass concentration) o...

  19. ‘Living’ PEGylation on gold nanoparticles to optimize cancer cell uptake by controlling targeting ligand and charge densities

    International Nuclear Information System (INIS)

    We report and demonstrate biomedical applications of a new technique—‘living’ PEGylation—that allows control of the density and composition of heterobifunctional PEG (HS-PEG-R; thiol-terminated poly(ethylene glycol)) on gold nanoparticles (AuNPs). We first establish ‘living’ PEGylation by incubating HS-PEG5000-COOH with AuNPs (∼20 nm) at increasing molar ratios from zero to 2000. This causes the hydrodynamic layer thickness to differentially increase up to 26 nm. The controlled, gradual increase in PEG-COOH density is revealed after centrifugation, based on the ability to re-suspend the pellet and increase the AuNP absorption. Using a fluorescamine-based assay we quantify differential HS-PEG5000-NH2 binding to AuNPs, revealing that it is highly efficient until AuNP saturation is reached. Furthermore, the zeta potential incrementally changes from −44.9 to +52.2 mV and becomes constant upon saturation. Using ‘living’ PEGylation we prepare AuNPs with different ratios of HS-PEG-RGD (RGD: Arg-Gly-Asp) and incubate them with U-87 MG (malignant glioblastoma) and non-target cells, demonstrating that targeting ligand density is critical to maximizing the efficiency of targeting of AuNPs to cancer cells. We also sequentially control the HS-PEG-R density to develop multifunctional nanoparticles, conjugating positively charged HS-PEG-NH2 at increasing ratios to AuNPs containing negatively charged HS-PEG-COOH to reduce uptake by macrophage cells. This ability to minimize non-specific binding/uptake by healthy cells could further improve targeted nanoparticle efficacy. (paper)

  20. Proteomic Profiling of Recombinant Escherichia coli in High-Cell- Density Fermentations for Improved Production of an Antibody Fragment Biopharmaceutical

    OpenAIRE

    Aldor, Ilana S.; Krawitz, Denise C.; Forrest, William; Chen, Christina; Nishihara, Julie C.; Joly, John C.; Champion, Kathleen M.

    2005-01-01

    By using two-dimensional polyacrylamide gel electrophoresis, a proteomic analysis over time was conducted with high-cell-density, industrial, phosphate-limited Escherichia coli fermentations at the 10-liter scale. During production, a recombinant, humanized antibody fragment was secreted and assembled in a soluble form in the periplasm. E. coli protein changes associated with culture conditions were distinguished from protein changes associated with heterologous protein expression. Protein sp...

  1. Small-bandgap polymer solar cells with unprecedented short-circuit current density and high fill factor.

    Science.gov (United States)

    Choi, Hyosung; Ko, Seo-Jin; Kim, Taehyo; Morin, Pierre-Olivier; Walker, Bright; Lee, Byoung Hoon; Leclerc, Mario; Kim, Jin Young; Heeger, Alan J

    2015-06-01

    Small-bandgap polymer solar cells (PSCs) with a thick bulk heterojunction film of 340 nm exhibit high power conversion efficiencies of 9.40% resulting from high short-circuit current density (JSC ) of 20.07 mA cm(-2) and fill factor of 0.70. This remarkable efficiency is attributed to maximized light absorption by the thick active layer and minimized recombination by the optimized lateral and vertical morphology through the processing additive. PMID:25899940

  2. Low platinum, high limiting current density of the PEMFC (proton exchange membrane fuel cell) based on multilayer cathode catalyst approach

    International Nuclear Information System (INIS)

    Novel multilayer cathode electrodes structures for PEMFC (proton exchange membrane fuel cell) based on sputtering technique were developed to provide high performance with low loading Pt of 0.05 mg/cm² compared to the standard MEA (membrane electrode assembly) cathode (∼0.2–0.3 mg/cm²). Different configurations of cathode catalyst layer were made by altering Pt and CN (Carbon–Nafion) ink carefully prepared on gas diffusion layer containing MPL (micro porous layer). The performances of PEMFC containing the multilayer electrodes were compared based on their measured polarization curves. Higher limiting current densities were achieved compared to standard MEA with platinum loading of 0.2 mg/cm² both at the cathode and the anode sides. Limiting current densities over 1.1 A/cm2, 1.2 A/cm2 and 1.4 A/cm2 were reached whereas maximum powers were in the range of 500 mW/cm² at 600 mW/cm². The good performances obtained can be due to the structural improvement which has contributed to a better catalyst utilization compared to conventional methods. A CN loading inferior to 0.24 mg/cm² between each layer is preferred for multilayer electrode. - Highlights: • Multilayer cathode of PEM fuel cell. • Enhanced performances with carbon–Nafion layer of PEM fuel cell. • Effect of the number of Pt sputtered layers on cell performance. • Increased power densities achieved. • Increased limiting current densities achieved

  3. Adiponectin inhibits oxidized low density lipoprotein-induced increase in matrix metalloproteinase 9 expression in vascular smooth muscle cells

    OpenAIRE

    Saneipour, Maryam; Ghatreh-Samani, Keihan; Heydarian, Esfandiar; Farrokhi, Effat; Abdian, Narges

    2015-01-01

    BACKGROUND High expression of matrix metalloproteinase 9 (MMP9) during vascular injury and inflammation plays an important role in atherosclerotic plaque formation and rupture. In the process of atherosclerosis, oxidized low-density lipoprotein (oxLDL) upregulates MMP9 in human aortic vascular smooth muscle cells (HA/VSMCs). Adiponectin is an adipose tissue-derived hormone that has been shown to exert anti-atherogenic and anti-inflammatory effects. The aim of this study was to investigate the...

  4. The relationship between the proliferation of parathyroid cell in rabbit with primary hyperparathyroidism and the bone mineral density

    International Nuclear Information System (INIS)

    Objective: To evaluate the relationship between the proliferation of parathyroid cell in rabbit with primary hyperparathyroidism (PHPT) and the bone mineral density (BMD). Methods: Eighty adult Chinese rabbits were randomly and equally divided into two groups. The contrast group was fed with normal diet (Ca: P, 1.0 : 0.7) and the experimental group was fed with high phosphate diet (Ca: P, 1.0 : 7.0) to establish the animal model of PHPT. At 3, 4, 5, and 6 months after the diet, bone mineral density of the rabbits was measured by the quantity CT (QCT). Then, the parathyroid and bone of the rabbits were removed for pathological examination. The number of parathyroid cell in PHPT was calculated. Proliferation was determined by immunohistochemistry of proliferation cell nuclear antigen (PCNA) and Bcl- 2. The t test and Logistic regression was used to analyze the difference of data of two groups. Result: The number of parathyroid cell in PHPT group was 1. 61 times than that in the contrast group [(673±1.51) HP, (418±2.5) HP, P3, P<0.05]. There was a negative correlation between BMD and PCNA (r=-0.749, P<0.05) and between BMD and Bcl-2 (r= -0.800, P<0.05) in PHPT group. Conclusion: The BMD of PHPT is related to the parathyroid cells proliferation which provide a reliable method for early diagnosis of PHPT. (authors)

  5. Molecular heterogeneity in a patient-derived glioblastoma xenoline is regulated by different cancer stem cell populations.

    Science.gov (United States)

    Garner, Jo Meagan; Ellison, David W; Finkelstein, David; Ganguly, Debolina; Du, Ziyun; Sims, Michelle; Yang, Chuan He; Interiano, Rodrigo B; Davidoff, Andrew M; Pfeffer, Lawrence M

    2015-01-01

    Malignant glioblastoma (GBM) is a highly aggressive brain tumor with a dismal prognosis and limited therapeutic options. Genomic profiling of GBM samples has identified four molecular subtypes (Proneural, Neural, Classical and Mesenchymal), which may arise from different glioblastoma stem-like cell (GSC) populations. We previously showed that adherent cultures of GSCs grown on laminin-coated plates (Ad-GSCs) and spheroid cultures of GSCs (Sp-GSCs) had high expression of stem cell markers (CD133, Sox2 and Nestin), but low expression of differentiation markers (βIII-tubulin and glial fibrillary acid protein). In the present study, we characterized GBM tumors produced by subcutaneous and intracranial injection of Ad-GSCs and Sp-GSCs isolated from a patient-derived xenoline. Although they formed tumors with identical histological features, gene expression analysis revealed that xenografts of Sp-GSCs had a Classical molecular subtype similar to that of bulk tumor cells. In contrast xenografts of Ad-GSCs expressed a Mesenchymal gene signature. Adherent GSC-derived xenografts had high STAT3 and ANGPTL4 expression, and enrichment for stem cell markers, transcriptional networks and pro-angiogenic markers characteristic of the Mesenchymal subtype. Examination of clinical samples from GBM patients showed that STAT3 expression was directly correlated with ANGPTL4 expression, and that increased expression of these genes correlated with poor patient survival and performance. A pharmacological STAT3 inhibitor abrogated STAT3 binding to the ANGPTL4 promoter and exhibited anticancer activity in vivo. Therefore, Ad-GSCs and Sp-GSCs produced histologically identical tumors with different gene expression patterns, and a STAT3/ANGPTL4 pathway is identified in glioblastoma that may serve as a target for therapeutic intervention. PMID:25955030

  6. CellBase, a comprehensive collection of RESTful web services for retrieving relevant biological information from heterogeneous sources

    Science.gov (United States)

    Bleda, Marta; Tarraga, Joaquin; de Maria, Alejandro; Salavert, Francisco; Garcia-Alonso, Luz; Celma, Matilde; Martin, Ainoha; Dopazo, Joaquin; Medina, Ignacio

    2012-01-01

    During the past years, the advances in high-throughput technologies have produced an unprecedented growth in the number and size of repositories and databases storing relevant biological data. Today, there is more biological information than ever but, unfortunately, the current status of many of these repositories is far from being optimal. Some of the most common problems are that the information is spread out in many small databases; frequently there are different standards among repositories and some databases are no longer supported or they contain too specific and unconnected information. In addition, data size is increasingly becoming an obstacle when accessing or storing biological data. All these issues make very difficult to extract and integrate information from different sources, to analyze experiments or to access and query this information in a programmatic way. CellBase provides a solution to the growing necessity of integration by easing the access to biological data. CellBase implements a set of RESTful web services that query a centralized database containing the most relevant biological data sources. The database is hosted in our servers and is regularly updated. CellBase documentation can be found at http://docs.bioinfo.cipf.es/projects/cellbase. PMID:22693220

  7. Differential gene expression in Neurospora crassa cell types: heterogeneity and amplification of rRNA genes. Progress report, July 1980-June 30, 1981

    International Nuclear Information System (INIS)

    The significant results obtained during 1980-1981 year of the current research program are as follows: I. Studies on heterogeneity of multiple copies of rDNAs from N. crassa cell types are being continued, such as: (1) Autoradiographs of Southern transfers of EcoR1 restricted fragments of nuclear DNA from conidia, germinated conidia (sprouts) and mycelia of N. crassa were compared after hybridization with 32P-rDNA probe. The nuclear DNA of two hours sprout and of 16 hours mycelia gave similar hybridization patterns with EcoR1 digest, but no such hybridization pattern was evident in conidial DNA digest; (2) Procedure for concentration of rDNAs from Neurospora species and cell types was standardized; restriction analysis of purified rDNAs is being done; (3) 35S total rDNA clone, 17S rDNA clone and 26S rDNA subclone are being used to see gross differences in the precursor rRNAs of different cell types; (4) Comparison of DNA:DNA homologies of rRNA genes with different Neurospora species. II. Post-mitochondrial DNAs of N. crassa are found to be rDNA-like and were further characterized by electron microscopic studies and are found to be approximately twice the size of SV-40 DNAs. These N. crassa post-mitochondrial DNAs hybridized with 32P-labeled N. crassa nuclear DNAs. III. Previous studies on differential RNase sensitive DNA polymerase activity in N. Crassa cell types and on evolution of sexual morphogenesis in the genus Neurospora are completed and published. RNase sensitive DNA polymerase activity is found to be in the post-mitochondrial fraction. Heterothallism in the genus Neurospora is evolved from homothallism

  8. High energy efficiency and high power density proton exchange membrane fuel cells: Electrode kinetics and mass transport

    Science.gov (United States)

    Srinivasan, Supramaniam; Velev, Omourtag A.; Parthasathy, Arvind; Manko, David J.; Appleby, A. John

    1991-01-01

    The development of proton exchange membrane (PEM) fuel cell power plants with high energy efficiencies and high power densities is gaining momentum because of the vital need of such high levels of performance for extraterrestrial (space, underwater) and terrestrial (power source for electric vehicles) applications. Since 1987, considerable progress has been made in achieving energy efficiencies of about 60 percent at a current density of 200 mA/sq cm and high power densities (greater than 1 W/sq cm) in PEM fuel cells with high (4 mg/sq cm) or low (0.4 mg/sq cm) platinum loadings in electrodes. The following areas are discussed: (1) methods to obtain these high levels of performance with low Pt loading electrodes - by proton conductor impregnation into electrodes, localization of Pt near front surface; (2) a novel microelectrode technique which yields electrode kinetic parameters for oxygen reduction and mass transport parameters; (3) demonstration of lack of water transport from anode to cathode; (4) modeling analysis of PEM fuel cell for comparison with experimental results and predicting further improvements in performance; and (5) recommendations of needed research and development for achieving the above goals.

  9. Lipoprotein lipase increases low density lipoprotein retention by subendothelial cell matrix.

    OpenAIRE

    Saxena, U; Klein, M. G.; Vanni, T M; Goldberg, I J

    1992-01-01

    Lipoprotein lipase (LPL), the rate-limiting enzyme for hydrolysis of plasma lipoprotein triglycerides, is a normal constituent of the arterial wall. We explored whether LPL affects (a) lipoprotein transport across bovine aortic endothelial cells or (b) lipoprotein binding to subendothelial cell matrix (retention). When bovine milk LPL was added to endothelial cell monolayers before addition of 125I-labeled LDL, LDL transport across the monolayers was unchanged; but, at all concentrations of L...

  10. Collision rates for rare cell capture in periodic obstacle arrays strongly depend on density of cell suspension.

    Science.gov (United States)

    Cimrák, I

    2016-11-01

    Recently, computational modelling has been successfully used for determination of collision rates for rare cell capture in periodic obstacle arrays. The models were based on particle advection simulations where the cells were advected according to velocity field computed from two dimensional Navier-Stokes equations. This approach may be used under the assumption of very dilute cell suspensions where no mutual cell collisions occur. We use the object-in-fluid framework to demonstrate that even with low cell-to-fluid ratio, the optimal geometry of the obstacle array significantly changes. We show computational simulations for ratios of 3.5, 6.9 and 10.4% determining the optimal geometry of the periodic obstacle arrays. It was already previously demonstrated that cells in periodic obstacle arrays follow trajectories in two modes: the colliding mode and the zig-zag mode. The colliding mode maximizes the cell-obstacle collision fr