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Sample records for cell populations resolves

  1. Periodicity in Age-Resolved Populations

    Science.gov (United States)

    Esipov, Sergei

    We discuss the interplay between the non-linear diffusion and age-resolved population dynamics. Depending on the age properties of collective migration the system may exhibit continuous joint expansion of all ages or continuous expansion with age segregation. Between these two obvious limiting regimes there is an interesting window of periodic expansion, which has been previously used by us in modeling bacterial colonies of Proteus mirabilis. In order to test whether the age-dependent collective migration leads to periodicity in other systems we performed a Fourier analysis of historical data on ethnic expansions and found multiple co-existing periods of activity.

  2. Spatially resolved fish population analysis for designing MPAs

    DEFF Research Database (Denmark)

    Christensen, Asbjørn; Mosegaard, Henrik; Jensen, Henrik

    2009-01-01

    The sandeel population analysis model (SPAM) is presented as a simulation tool for exploring the efficiency of Marine Protected Areas (MPAs) for sandeel stocks. SPAM simulates spatially resolved sandeel population distributions, based on a high-resolution map of all fishery-established sandbank...... habitats for settled sandeels, combined with a life-cycle model for survival, growth, and reproduction, and a three-dimensional hydrodynamic model for describing larval transport between the network of habitats. SPAM couples stock dynamics to ecosystem and anthropogenic forcing via well-defined drivers....... The SPAM framework was tested using ICES statistical rectangle 37F2 as an MPA, and the impact on sandeel populations within the MPA and neighbouring habitats was investigated. Increased larval spillover compensated for lost catches inside the MPA. The temporal and spatial scales of stock response to...

  3. Resolving archaeological populations with Sr-isotope mixing models

    International Nuclear Information System (INIS)

    Strontium isotope analysis of tooth enamel is a useful provenancing technique to investigate the childhood origins and residential mobility of ancient people. However, where different geographical target regions have similar biosphere 87Sr/86Sr it is often difficult to resolve the 87Sr/86Sr ranges of two different groups of people and establish what constitutes the local range at each site. Here a multi-period study is presented from the Outer Hebrides, Scotland and an investigation of Neolithic and Early Bronze Age populations from the Yorkshire Wolds, NE England. The aim is to demonstrate that, despite complex human dietary strategies, simple mixing systems with only two end-members do occur in archaeological human populations in certain geological provinces and, despite overlapping 87Sr/86Sr ranges, it is possible to separate two populations based on the structure within the data set

  4. The Dark Energy Survey: Prospects for resolved stellar populations

    Energy Technology Data Exchange (ETDEWEB)

    Rossetto, Bruno M. [Observatorio Nacional, Rio de Janeiro (Brazil); Lab. Interinstitucional de e-Astronomia-LIneA, Rio de Janeiro (Brazil); Santiago, Basílio X. [Lab. Interinstitucional de e-Astronomia-LIneA, Rio de Janeiro (Brazil); Instituto de Fisica, Porto Alegre (Brazil); Girardi, Léo [Lab. Interinstitucional de e-Astronomia-LIneA, Rio de Janeiro (Brazil); Osservatorio Astronomica di Padova-INAF, Padova (Italy); Camargo, Julio I. B. [Observatorio Nacional, Rio de Janeiro (Brazil); Lab. Interinstitucional de e-Astronomia-LIneA, Rio de Janeiro (Brazil); Balbinot, Eduardo [Lab. Interinstitucional de e-Astronomia-LIneA, Rio de Janeiro (Brazil); Instituto de Fisica, Porto Alegre (Brazil); da Costa, Luiz N. [Observatorio Nacional, Rio de Janeiro (Brazil); Lab. Interinstitucional de e-Astronomia-LIneA, Rio de Janeiro (Brazil); Yanny, Brian [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Maia, Marcio A. G. [Observatorio Nacional, Rio de Janeiro (Brazil); Lab. Interinstitucional de e-Astronomia-LIneA, Rio de Janeiro (Brazil); Makler, Martin [Lab. Interinstitucional de e-Astronomia-LIneA, Rio de Janeiro (Brazil); Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro (Brazil); Ogando, Ricardo L. C. [Observatorio Nacional, Rio de Janeiro (Brazil); Lab. Interinstitucional de e-Astronomia-LIneA, Rio de Janeiro (Brazil); Pellegrini, Paulo S. [Observatorio Nacional, Rio de Janeiro (Brazil); Lab. Interinstitucional de e-Astronomia-LIneA, Rio de Janeiro (Brazil); Ramos, Beatriz [Observatorio Nacional, Rio de Janeiro (Brazil); Lab. Interinstitucional de e-Astronomia-LIneA, Rio de Janeiro (Brazil); de Simoni, Fernando [Observatorio Nacional, Rio de Janeiro (Brazil); Lab. Interinstitucional de e-Astronomia-LIneA, Rio de Janeiro (Brazil); Armstrong, R. [Univ. of Illinois, Urbana, IL (United States); Bertin, E. [Univ. Pierre et Marie Curie, Paris (France); Desai, S. [Univ. of Illinois, Urbana, IL (United States); Kuropatkin, N. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Lin, H. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Mohr, J. J. [Max-Planck-Institut fur extraterrestrische Physik, Garching (Germany); Tucker, D. L. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2011-05-06

    Wide angle and deep surveys, regardless of their primary purpose, always sample a large number of stars in the Galaxy and in its satellite system. We here make a forecast of the expected stellar sample resulting from the Dark Energy Survey and the perspectives that it will open for studies of Galactic structure and resolved stellar populations in general. An estimated 1.2 x 108 stars will be sampled in DES grizY filters in the southern equatorial hemisphere. This roughly corresponds to 20% of all DES sources. Most of these stars belong to the stellar thick disk and halo of the Galaxy.

  5. Resolved Near-Infrared Stellar Populations in Nearby Galaxies

    CERN Document Server

    Dalcanton, Julianne J; Melbourne, Jason L; Girardi, Léo; Dolphin, Andy; Rosenfield, Philip A; Boyer, Martha L; de Jong, Roelof S; Gilbert, Karoline; Marigo, Paola; Olsen, Knut; Seth, Anil C; Skillman, Evan

    2011-01-01

    We present near-infrared (NIR) color-magnitude diagrams (CMDs) for the resolved stellar populations within 26 fields of 23 nearby galaxies (<4 Mpc), based on F110W and F160W images from Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST). The CMDs sample both old dormant and young star-forming populations. We match key NIR CMD features with their counterparts in optical CMDs, and identify the red core Helium burning (RHeB) sequence as a significant contributor to the NIR flux in stellar populations younger than a few 100 Myrs old, suggesting that star formation can drive surprisingly rapid variations in the NIR mass-to-light ratio. The NIR luminosity of star forming galaxies is therefore not necessarily proportional to the stellar mass. We note that these individual bright RHeB stars may be misidentified as old stellar clusters in low resolution imaging. We also discuss the CMD location of asymptotic giant branch (AGB) stars, and the separation of AGB sub-populations using a combination of optic...

  6. [China's population policies: attempting to "resolve the wrong problem"?].

    Science.gov (United States)

    Ratcliffe, J W

    1989-03-01

    This work argues that international efforts to resolve the population problem have failed primarily because they have been based on misconceptions concerning the definition of the problem and the relationship between population growth and development. The demographic experience of the People's Republic of China since the Revolution is used to illustrate these commonly shared misconceptions. The difficulty of defining the population problem results from differing interpretations of the basic fact that poor population groups tend to have higher fertility rates and faster growth than wealthier population groups. The Western industrial nations maintain that peoples or countries are poor because they have many children; the solution to the problem would require that they be provided access to modern contraception and associated services such as population and family planning education. Many Third World countries argue on the other hand that people have many children because they are poor, a view implying that greater social and economic development will provide the solution. The disagreement as to whether rapid population growth is a cause or a consequence of underdevelopment results in part from viewing overpopulation and underdevelopment as separate and distinct problems. Results of several carefully conducted evaluation studies have demonstrated that very little of the world fertility decline in the late 1960s and early 1970s was attributable to national family planning programs. Research has shown that equitable division of national wealth, education--especially of women, some employment factors such as a lack of opportunities for children, and a reliable social security system are the most powerful determinants of fertility. The studies indicate that fertility declines are induced by models of development that stress widespread social progress rather than provision of contraceptives and associated services. Examination of the Chinese demographic experience suggests

  7. The Dark Energy Survey: Prospects for Resolved Stellar Populations

    CERN Document Server

    Rossetto, B M; Girardi, L; Camargo, J I B; Balbinot, E; da Costa, L N; Yanny, B; Maia, M A G; Makler, M; Ogando, R L C; Pellegrini, P S; Ramos, B; de Simoni, F; Armstrong, R; Bertin, E; Desai, S; Kuropatkin, N; Lin, H; Mohr, J J; Tucker, D L

    2011-01-01

    Wide angle and deep surveys, regardless of their primary purpose, always sample a large number of stars in the Galaxy and in its satellite system. We here make a forecast of the expected stellar sample resulting from the Dark Energy Survey and the perspectives that it will open for studies of Galactic structure and resolved stellar populations in general. An estimated 1.2x10^8 stars will be sampled in DES grizY filters. This roughly corresponds to 20% of all DES sources. Most of these stars belong to the stellar thick disk and halo of the Galaxy. DES will probe low-mass stellar and sub-stellar objects at depths from 3 to 8 times larger than SDSS. The faint end of the main-sequence will be densely sampled beyond 10 kpc. The slope of the low mass end of the stellar IMF will be constrained to within a few hundredth dex, even in the thick disk and halo. In the sub-stellar mass regime, the IMF slope will be potentially constrained to within dlog \\phi(m) / dlog m ~ 0.1$. About 3x10^4 brown dwarf and at least 7.6x10...

  8. Sensing cell metabolism by time-resolved autofluorescence

    Science.gov (United States)

    Wu, Yicong; Zheng, Wei; Qu, Jianan Y.

    2006-11-01

    We built a time-resolved confocal fluorescence spectroscopy system equipped with the multichannel time-correlated single-photon-counting technique. The instrument provides a unique approach to study the fluorescence sensing of cell metabolism via analysis of the wavelength- and time-resolved intracellular autofluorescence. The experiments on monolayered cell cultures show that with UV excitation at 365 nm the time-resolved autofluorescence decays, dominated by free-bound reduced nicotinamide adenine dinucleotide signals, are sensitive indicators for cell metabolism. However, the sensitivity decreases with the increase of excitation wavelength possibly due to the interference from free-bound flavin adenine dinucleotide fluorescence. The results demonstrate that time-resolved autofluorescence can be potentially used as an important contrast mechanism to detect epithelial precancer.

  9. Resolving the ancestry of Austronesian-speaking populations.

    Science.gov (United States)

    Soares, Pedro A; Trejaut, Jean A; Rito, Teresa; Cavadas, Bruno; Hill, Catherine; Eng, Ken Khong; Mormina, Maru; Brandão, Andreia; Fraser, Ross M; Wang, Tse-Yi; Loo, Jun-Hun; Snell, Christopher; Ko, Tsang-Ming; Amorim, António; Pala, Maria; Macaulay, Vincent; Bulbeck, David; Wilson, James F; Gusmão, Leonor; Pereira, Luísa; Oppenheimer, Stephen; Lin, Marie; Richards, Martin B

    2016-03-01

    There are two very different interpretations of the prehistory of Island Southeast Asia (ISEA), with genetic evidence invoked in support of both. The "out-of-Taiwan" model proposes a major Late Holocene expansion of Neolithic Austronesian speakers from Taiwan. An alternative, proposing that Late Glacial/postglacial sea-level rises triggered largely autochthonous dispersals, accounts for some otherwise enigmatic genetic patterns, but fails to explain the Austronesian language dispersal. Combining mitochondrial DNA (mtDNA), Y-chromosome and genome-wide data, we performed the most comprehensive analysis of the region to date, obtaining highly consistent results across all three systems and allowing us to reconcile the models. We infer a primarily common ancestry for Taiwan/ISEA populations established before the Neolithic, but also detected clear signals of two minor Late Holocene migrations, probably representing Neolithic input from both Mainland Southeast Asia and South China, via Taiwan. This latter may therefore have mediated the Austronesian language dispersal, implying small-scale migration and language shift rather than large-scale expansion. PMID:26781090

  10. Retinal Ganglion Cell Distribution and Spatial Resolving Power in Deep-Sea Lanternfishes (Myctophidae)

    KAUST Repository

    De Busserolles, Fanny

    2014-01-01

    Topographic analyses of retinal ganglion cell density are very useful in providing information about the visual ecology of a species by identifying areas of acute vision within the visual field (i.e. areas of high cell density). In this study, we investigated the neural cell distribution in the ganglion cell layer of a range of lanternfish species belonging to 10 genera. Analyses were performed on wholemounted retinas using stereology. Topographic maps were constructed of the distribution of all neurons and both ganglion and amacrine cell populations in 5 different species from Nissl-stained retinas using cytological criteria. Amacrine cell distribution was also examined immunohistochemically in 2 of the 5 species using anti-parvalbumin antibody. The distributions of both the total neuron and the amacrine cell populations were aligned in all of the species examined, showing a general increase in cell density toward the retinal periphery. However, when the ganglion cell population was topographically isolated from the amacrine cell population, which comprised up to 80% of the total neurons within the ganglion cell layer, a different distribution was revealed. Topographic maps of the true ganglion cell distribution in 18 species of lanternfishes revealed well-defined specializations in different regions of the retina. Different species possessed distinct areas of high ganglion cell density with respect to both peak density and the location and/or shape of the specialized acute zone (i.e. elongated areae ventro-temporales, areae temporales and large areae centrales). The spatial resolving power was calculated to be relatively low (varying from 1.6 to 4.4 cycles per degree), indicating that myctophids may constitute one of the less visually acute groups of deep-sea teleosts. The diversity in retinal specializations and spatial resolving power within the family is assessed in terms of possible ecological functions and evolutionary history.

  11. Retinal ganglion cell distribution and spatial resolving power in elasmobranchs.

    Science.gov (United States)

    Lisney, Thomas J; Collin, Shaun P

    2008-01-01

    The total number, distribution and peak density of presumed retinal ganglion cells was assessed in 10 species of elasmobranch (nine species of shark and one species of batoid) using counts of Nissl-stained cells in retinal wholemounts. The species sampled include a number of active, predatory benthopelagic and pelagic sharks that are found in a variety of coastal and oceanic habitats and represent elasmobranch groups for which information of this nature is currently lacking. The topographic distribution of cells was heterogeneous in all species. Two benthic species, the shark Chiloscyllium punctatum and the batoid Taeniura lymma, have a dorsal or dorso-central horizontal streak of increased cell density, whereas the majority of the benthopelagic and pelagic sharks examined exhibit a more concentric pattern of increasing cell density, culminating in a central area centralis of higher cell density located close to the optic nerve head. The exception is the shark Alopias superciliosus, which possesses a ventral horizontal streak. Variation in retinal ganglion cell topography appears to be related to the visual demands of different habitats and lifestyles, as well as the positioning of the eyes in the head. The upper limits of spatial resolving power were calculated for all 10 species, using peak ganglion cell densities and estimates of focal length taken from cryo-sectioned eyes in combination with information from the literature. Spatial resolving power ranged from 2.02 to 10.56 cycles deg(-1), which is in accordance with previous studies. Species with a lower spatial resolving power tend to be benthic and/or coastal species that feed on benthic invertebrates and fishes. Active, benthopelagic and pelagic species from more oceanic habitats which feed on larger, more active prey, possess a higher resolving power. Additionally, ganglion cells in a juvenile of C. punctatum, were retrogradely-labeled from the optic nerve with biotinylated dextran amine (BDA). A comparison

  12. Time-resolved local strain tracking microscopy for cell mechanics

    Science.gov (United States)

    Aydin, O.; Aksoy, B.; Akalin, O. B.; Bayraktar, H.; Alaca, B. E.

    2016-02-01

    A uniaxial cell stretching technique to measure time-resolved local substrate strain while simultaneously imaging adherent cells is presented. The experimental setup comprises a uniaxial stretcher platform compatible with inverted microscopy and transparent elastomer samples with embedded fluorescent beads. This integration enables the acquisition of real-time spatiotemporal data, which is then processed using a single-particle tracking algorithm to track the positions of fluorescent beads for the subsequent computation of local strain. The present local strain tracking method is demonstrated using polydimethylsiloxane (PDMS) samples of rectangular and dogbone geometries. The comparison of experimental results and finite element simulations for the two sample geometries illustrates the capability of the present system to accurately quantify local deformation even when the strain distribution is non-uniform over the sample. For a regular dogbone sample, the experimentally obtained value of local strain at the center of the sample is 77%, while the average strain calculated using the applied cross-head displacement is 48%. This observation indicates that considerable errors may arise when cross-head measurement is utilized to estimate strain in the case of non-uniform sample geometry. Finally, the compatibility of the proposed platform with biological samples is tested using a unibody PDMS sample with a well to contain cells and culture media. HeLa S3 cells are plated on collagen-coated samples and cell adhesion and proliferation are observed. Samples with adherent cells are then stretched to demonstrate simultaneous cell imaging and tracking of embedded fluorescent beads.

  13. Resolving the role of actoymyosin contractility in cell microrheology.

    Directory of Open Access Journals (Sweden)

    Christopher M Hale

    Full Text Available Einstein's original description of Brownian motion established a direct relationship between thermally-excited random forces and the transport properties of a submicron particle in a viscous liquid. Recent work based on reconstituted actin filament networks suggests that nonthermal forces driven by the motor protein myosin II can induce large non-equilibrium fluctuations that dominate the motion of particles in cytoskeletal networks. Here, using high-resolution particle tracking, we find that thermal forces, not myosin-induced fluctuating forces, drive the motion of submicron particles embedded in the cytoskeleton of living cells. These results resolve the roles of myosin II and contractile actomyosin structures in the motion of nanoparticles lodged in the cytoplasm, reveal the biphasic mechanical architecture of adherent cells-stiff contractile stress fibers interdigitating in a network at the cell cortex and a soft actin meshwork in the body of the cell, validate the method of particle tracking-microrheology, and reconcile seemingly disparate atomic force microscopy (AFM and particle-tracking microrheology measurements of living cells.

  14. Testing Density Wave Theory with Resolved Stellar Populations around Spiral Arms in M81

    CERN Document Server

    Choi, Yumi; Williams, Benjamin F; Weisz, Daniel R; Skillman, Evan D; Fouesneau, Morgan; Dolphin, Andrew E

    2015-01-01

    Stationary density waves rotating at a constant pattern speed $\\Omega_{\\rm P}$ would produce age gradients across spiral arms. We test whether such age gradients are present in M81 by deriving the recent star formation histories (SFHs) of 20 regions around one of M81's grand-design spiral arms. For each region, we use resolved stellar populations to determine the SFH by modeling the observed color-magnitude diagram (CMD) constructed from archival Hubble Space Telescope (HST) F435W and F606W imaging. Although we should be able to detect systematic time delays in our spatially-resolved SFHs, we find no evidence of star formation propagation across the spiral arm. Our data therefore provide no convincing evidence for a stationary density wave with a single pattern speed in M81, and instead favor the scenario of kinematic spiral patterns that are likely driven by tidal interactions with the companion galaxies M82 and NGC 3077.

  15. On the Incorporation of Metallicity Data into Star Formation History Measurements from Resolved Stellar Populations

    CERN Document Server

    Dolphin, Andrew E

    2016-01-01

    The combination of spectroscopic stellar metallicities and resolved star color-magnitude diagrams (CMDs) has the potential to constrain the entire star formation and chemical enrichment history (SFH) of a galaxy better than fitting CMDs alone (as is most common in SFH studies using resolved stellar populations). In this paper, two approaches for incorporating external metallicity information into color-magnitude diagram fitting techniques are presented. Overall, the joint fitting of metallicity and CMD information can increase the precision on measured age-metallicity relationships and star formation rates by ~10% over CMD fitting alone. However, systematics in stellar isochrones and mismatches between spectroscopic and photometric metallicity determinations can reduce the accuracy of the recovered SFHs. I present a simple mitigation of these systematics that can reduce the amplitude of these systematics to the level obtained from CMD fitting alone, while ensuring the age-metallicity relationship is consisten...

  16. Stellar population gradients and spatially resolved kinematics in luminous post-starburst galaxies

    CERN Document Server

    Pracy, M B; Sadler, E; Couch, W J; Kuntschner, H; Bekki, K; Owers, M S; Zwaan, M; Turner, J; Bergmann, M

    2013-01-01

    We have used deep integral field spectroscopy obtained with the GMOS instrument on Gemini-North to determine the spatial distribution of the post-starburst stellar population in four luminous E+A galaxies at z<0.04. We find all four galaxies have centrally-concentrated gradients in the young stellar population contained within the central ~1 kpc. This is in agreement with the Balmer line gradients found in local low luminosity E+A galaxies. The results from higher redshift (z~0.1) samples of luminous E+A galaxies have been varied, but in general have found the post-starburst signature to be extended or a galaxy-wide phenomenon or have otherwise failed to detect gradients in the stellar populations. The ubiquity of the detection of a centrally concentrated young stellar population in local samples, and the presence of significant radial gradients in the stellar populations when the E+A galaxy core is well resolved raises the possibility that spatial resolution issues may be important in interpreting the hig...

  17. Time-resolved multiphoton imaging of basal cell carcinoma

    Science.gov (United States)

    Cicchi, R.; Sestini, S.; De Giorgi, V.; Stambouli, D.; Carli, P.; Massi, D.; Pavone, F. S.

    2007-02-01

    We investigated human cutaneous basal cell carcinoma ex-vivo samples by combined time resolved two photon intrinsic fluorescence and second harmonic generation microscopy. Morphological and spectroscopic differences were found between malignant skin and corresponding healthy skin tissues. In comparison with normal healthy skin, cancer tissue showed a different morphology and a mean fluorescence lifetime distribution slightly shifted towards higher values. Topical application of delta-aminolevulinic acid to the lesion four hours before excision resulted in an enhancement of the fluorescence signal arising from malignant tissue, due to the accumulation of protoporphyrines inside tumor cells. Contrast enhancement was prevalent at tumor borders by both two photon fluorescence microscopy and fluorescence lifetime imaging. Fluorescence-based images showed a good correlation with conventional histopathological analysis, thereby supporting the diagnostic accuracy of this novel method. Combined morphological and lifetime analysis in the study of ex-vivo skin samples discriminated benign from malignant tissues, thus offering a reliable, non-invasive tool for the in-vivo analysis of inflammatory and neoplastic skin lesions.

  18. Unresolved versus resolved: testing the validity of young simple stellar population models with VLT/MUSE observations of NGC 3603

    CERN Document Server

    Kuncarayakti, H; Anderson, J P; Krühler, T; Hamuy, M

    2016-01-01

    CONTEXT. Stellar populations are the building blocks of galaxies including the Milky Way. The majority, if not all extragalactic studies are entangled with the use of stellar population models given the unresolved nature of their observation. Extragalactic systems contain multiple stellar populations with complex star formation histories. However, their study is mainly based upon the principles of simple stellar populations (SSP). Hence, it is critical to examine the validity of SSP models. AIMS. This work aims to empirically test the validity of SSP models. This is done by comparing SSP models against observations of spatially resolved young stellar population in the determination of its physical properties, i.e. age and metallicity. METHODS. Integral field spectroscopy of a young stellar cluster in the Milky Way, NGC 3603, is used to study the properties of the cluster both as a resolved and unresolved stellar population. The unresolved stellar population is analysed using the H$\\alpha$ equivalent width as ...

  19. Virgo cluster and field dwarf ellipticals in 3D: III. Spatially and temporally resolved stellar populations

    CERN Document Server

    Ryś, Agnieszka; Falcón-Barroso, Jesús; Vazdekis, Alexandre; Lisker, Thorsten; Peletier, Reynier; van de Ven, Glenn

    2015-01-01

    We present the stellar population analysis of a sample of 12 dwarf elliptical galaxies, observed with the SAURON integral field unit, using the full-spectrum fitting method. We show that star formation histories (SFHs) resolved into two populations can be recovered even within a limited wavelength range, provided that high S/N data is used. We confirm that dEs have had complex SFHs, with star formation extending to (more) recent epochs: for the majority of our galaxies star formation activity was either still strong a few ($\\lesssim$ 5) Gyr ago or they experienced a secondary burst of star formation roughly at that time. This latter possibility is in agreement with the proposed dE formation scenario where tidal harassment drives the gas remaining in their progenitors inwards and induces a star formation episode. For one of our field galaxies, ID0918, we find a correlation between its stellar population and kinematic properties, pointing to a possible merger origin of its kinematically-decoupled core. One of o...

  20. Spatially resolved stellar population parameters in the BCGs of two fossil groups

    CERN Document Server

    Proctor, Robert N; Eigenthaler, Paul

    2014-01-01

    We report the results of Gemini/GMOS long-slit spectroscopic observations along the major and minor axes of the central galaxies in two fossil groups, SDSS J073422.21+265133.9 and SDSS J075828.11+374711.8 (the NGC 2484 group). Spatially resolved kinematics and stellar population parameters (ages, metallicities and $\\alpha$-element abundance ratios) derived using ~20 Lick indices are presented. Despite remarkable similarities in their morphologies, photometric properties (luminosity and colour) and kinematics, the two galaxies exhibit significantly different stellar population parameters. SDSS J073422.21+265133.9 exhibits a strong metallicity gradient (Delta[Z/H]/Delta R ~ -0.4) all the way into the centre of the galaxy. It also exhibits an age profile that suggest a relatively recent, centrally concentrated burst of star formation superimposed on an older, more spatially extended population. NGC 2484, a well known X-ray AGN, exhibits a flat core-like structure in its metallicity gradient, but no detectable ag...

  1. On the Incorporation of Metallicity Data into Measurements of Star Formation History from Resolved Stellar Populations

    Science.gov (United States)

    Dolphin, Andrew E.

    2016-07-01

    The combination of spectroscopic stellar metallicities and resolved star color–magnitude diagrams (CMDs) has the potential to constrain the entire star formation history (SFH) of a galaxy better than fitting CMDs alone (as is most common in SFH studies using resolved stellar populations). In this paper, two approaches to incorporating external metallicity information into CMD-fitting techniques are presented. Overall, the joint fitting of metallicity and CMD information can increase the precision of measured age–metallicity relationships (AMRs) and star formation rates by 10% over CMD fitting alone. However, systematics in stellar isochrones and mismatches between spectroscopic and photometric determinations of metallicity can reduce the accuracy of the recovered SFHs. I present a simple mitigation of these systematics that can reduce their amplitude to the level obtained from CMD fitting alone, while ensuring that the AMR is consistent with spectroscopic metallicities. As is the case in CMD-fitting analysis, improved stellar models and calibrations between spectroscopic and photometric metallicities are currently the primary impediment to gains in SFH precision from jointly fitting stellar metallicities and CMDs.

  2. Resolving Discrepant Findings on ANGPTL8 in β-Cell Proliferation: A Collaborative Approach to Resolving the Betatrophin Controversy

    Science.gov (United States)

    Cox, Aaron R.; Rios, Jacqueline S.; Chavez, Julia; Bonnyman, Claire W.; Lam, Carol J.; Yi, Peng; Melton, Douglas A.

    2016-01-01

    The β-cell mitogenic effects of ANGPTL8 have been subjected to substantial debate. The original findings suggested that ANGPTL8 overexpression in mice induced a 17-fold increase in β-cell proliferation. Subsequent studies in mice contested this claim, but a more recent report in rats supported the original observations. These conflicting results might be explained by variable ANGPTL8 expression and differing methods of β-cell quantification. To resolve the controversy, three independent labs collaborated on a blinded study to test the effects of ANGPTL8 upon β-cell proliferation. Recombinant human betatrophin (hBT) fused to maltose binding protein (MBP) was delivered to mice by intravenous injection. The results demonstrate that ANGPTL8 does not stimulate significant β-cell proliferation. Each lab employed different methods for β-cell identification, resulting in variable quantification of β-cell proliferation and suggests a need for standardizing practices for β-cell quantification. We also observed a new action of ANGPTL8 in stimulating CD45+ hematopoietic-derived cell proliferation which may explain, in part, published discrepancies. Overall, the hypothesis that ANGPTL8 induces dramatic and specific β-cell proliferation can no longer be supported. However, while ANGPTL8 does not stimulate robust β-cell proliferation, the original experimental model using drug-induced (S961) insulin resistance was validated in subsequent studies, and thus still represents a robust system for studying signals that are either necessary or sufficient for β-cell expansion. As an added note, we would like to commend collaborative group efforts, with repetition of results and procedures in multiple laboratories, as an effective method to resolve discrepancies in the literature. PMID:27410263

  3. Quantifying selection in evolving populations using time-resolved genetic data

    International Nuclear Information System (INIS)

    Methods which uncover the molecular basis of the adaptive evolution of a population address some important biological questions. For example, the problem of identifying genetic variants which underlie drug resistance, a question of importance for the treatment of pathogens, and of cancer, can be understood as a matter of inferring selection. One difficulty in the inference of variants under positive selection is the potential complexity of the underlying evolutionary dynamics, which may involve an interplay between several contributing processes, including mutation, recombination and genetic drift. A source of progress may be found in modern sequencing technologies, which confer an increasing ability to gather information about evolving populations, granting a window into these complex processes. One particularly interesting development is the ability to follow evolution as it happens, by whole-genome sequencing of an evolving population at multiple time points. We here discuss how to use time-resolved sequence data to draw inferences about the evolutionary dynamics of a population under study. We begin by reviewing our earlier analysis of a yeast selection experiment, in which we used a deterministic evolutionary framework to identify alleles under selection for heat tolerance, and to quantify the selection acting upon them. Considering further the use of advanced intercross lines to measure selection, we here extend this framework to cover scenarios of simultaneous recombination and selection, and of two driver alleles with multiple linked neutral, or passenger, alleles, where the driver pair evolves under an epistatic fitness landscape. We conclude by discussing the limitations of the approach presented and outlining future challenges for such methodologies. (paper)

  4. The WFC3 Galactic Bulge Treasury Program: A First Look at Resolved Stellar Population Tools

    CERN Document Server

    Brown, Thomas M; Zoccali, Manuela; Renzini, Alvio; Ferguson, Henry C; Anderson, Jay; Smith, Ed; Bond, Howard E; Minniti, Dante; Valenti, Jeff A; Casertano, Stefano; Livio, Mario; Panagia, Nino; VandenBerg, Don A; Valenti, Elena

    2008-01-01

    [Abridged] When WFC3 is installed on HST, the community will have powerful new tools for investigating resolved stellar populations. The WFC3 Galactic Bulge Treasury program will obtain deep imaging on 4 low-extinction fields. These non-proprietary data will enable a variety of science investigations not possible with previous data sets. To aid in planning for the use of these data and for future proposals, we provide an introduction to the program, its photometric system, and the associated calibration effort. The observing strategy is based upon a new 5-band photometric system spanning the UV, optical, and near-infrared. With these broad bands, one can construct reddening-free indices of Teff and [Fe/H]. Besides the 4 bulge fields, the program will target 6 fields in well-studied star clusters, spanning a wide range of [Fe/H]. The cluster data serve to calibrate the indices, provide population templates, and correct the transformation of isochrones into the WFC3 photometric system. The bulge data will shed ...

  5. A New Method for Deriving the Stellar Birth Function of Resolved Stellar Populations.

    Science.gov (United States)

    Gennaro, M.; Tchernyshyov, K.; Brown, T. M.; Gordon, K. D.

    2015-07-01

    We present a new method for deriving the stellar birth function (SBF) of resolved stellar populations. The SBF (stars born per unit mass, time, and metallicity) is the combination of the initial mass function (IMF), the star formation history (SFH), and the metallicity distribution function (MDF). The framework of our analysis is that of Poisson Point Processes (PPPs), a class of statistical models suitable when dealing with points (stars) in a multidimensional space (the measurement space of multiple photometric bands). The theory of PPPs easily accommodates the modeling of measurement errors as well as that of incompleteness. Our method avoids binning stars in the color–magnitude diagram and uses the whole likelihood function for each data point; combining the individual likelihoods allows the computation of the posterior probability for the population's SBF. Within the proposed framework it is possible to include nuisance parameters, such as distance and extinction, by specifying their prior distributions and marginalizing over them. The aim of this paper is to assess the validity of this new approach under a range of assumptions, using only simulated data. Forthcoming work will show applications to real data. Although it has a broad scope of possible applications, we have developed this method to study multi-band Hubble Space Telescope observations of the Milky Way Bulge. Therefore we will focus on simulations with characteristics similar to those of the Galactic Bulge. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at STScI, which is operated by AURA, Inc., under NASA contract NAS 5-26555.

  6. PeakForce Tapping resolves individual microvilli on living cells.

    Science.gov (United States)

    Schillers, Hermann; Medalsy, Izhar; Hu, Shuiqing; Slade, Andrea L; Shaw, James E

    2016-02-01

    Microvilli are a common structure found on epithelial cells that increase the apical surface thus enhancing the transmembrane transport capacity and also serve as one of the cell's mechanosensors. These structures are composed of microfilaments and cytoplasm, covered by plasma membrane. Epithelial cell function is usually coupled to the density of microvilli and its individual size illustrated by diseases, in which microvilli degradation causes malabsorption and diarrhea. Atomic force microscopy (AFM) has been widely used to study the topography and morphology of living cells. Visualizing soft and flexible structures such as microvilli on the apical surface of a live cell has been very challenging because the native microvilli structures are displaced and deformed by the interaction with the probe. PeakForce Tapping® is an AFM imaging mode, which allows reducing tip-sample interactions in time (microseconds) and controlling force in the low pico-Newton range. Data acquisition of this mode was optimized by using a newly developed PeakForce QNM-Live Cell probe, having a short cantilever with a 17-µm-long tip that minimizes hydrodynamic effects between the cantilever and the sample surface. In this paper, we have demonstrated for the first time the visualization of the microvilli on living kidney cells with AFM using PeakForce Tapping. The structures observed display a force dependence representing either the whole microvilli or just the tips of the microvilli layer. Together, PeakForce Tapping allows force control in the low pico-Newton range and enables the visualization of very soft and flexible structures on living cells under physiological conditions. PMID:26414320

  7. Cell population-specific expression analysis of human cerebellum

    Directory of Open Access Journals (Sweden)

    Kuhn Alexandre

    2012-11-01

    Full Text Available Abstract Background Interpreting gene expression profiles obtained from heterogeneous samples can be difficult because bulk gene expression measures are not resolved to individual cell populations. We have recently devised Population-Specific Expression Analysis (PSEA, a statistical method that identifies individual cell types expressing genes of interest and achieves quantitative estimates of cell type-specific expression levels. This procedure makes use of marker gene expression and circumvents the need for additional experimental information like tissue composition. Results To systematically assess the performance of statistical deconvolution, we applied PSEA to gene expression profiles from cerebellum tissue samples and compared with parallel, experimental separation methods. Owing to the particular histological organization of the cerebellum, we could obtain cellular expression data from in situ hybridization and laser-capture microdissection experiments and successfully validated computational predictions made with PSEA. Upon statistical deconvolution of whole tissue samples, we identified a set of transcripts showing age-related expression changes in the astrocyte population. Conclusions PSEA can predict cell-type specific expression levels from tissues homogenates on a genome-wide scale. It thus represents a computational alternative to experimental separation methods and allowed us to identify age-related expression changes in the astrocytes of the cerebellum. These molecular changes might underlie important physiological modifications previously observed in the aging brain.

  8. Cell resolved, multiparticle model of plastic tissue deformations and morphogenesis

    International Nuclear Information System (INIS)

    We propose a three-dimensional mechanical model of embryonic tissue dynamics. Mechanically coupled adherent cells are represented as particles interconnected with elastic beams which can exert non-central forces and torques. Tissue plasticity is modeled by a stochastic process consisting of a connectivity change (addition or removal of a single link) followed by a complete relaxation to mechanical equilibrium. In particular, we assume that (i) two non-connected, but adjacent particles can form a new link; and (ii) the lifetime of links is reduced by tensile forces. We demonstrate that the proposed model yields a realistic macroscopic elasto-plastic behavior and we establish how microscopic model parameters determine material properties at the macroscopic scale. Based on these results, microscopic parameter values can be inferred from tissue thickness, macroscopic elastic modulus and the magnitude and dynamics of intercellular adhesion forces. In addition to their mechanical role, model particles can also act as simulation agents and actively modulate their connectivity according to specific rules. As an example, anisotropic link insertion and removal probabilities can give rise to local cell intercalation and large scale convergent extension movements. The proposed stochastic simulation of cell activities yields fluctuating tissue movements which exhibit the same autocorrelation properties as empirical data from avian embryos. (paper)

  9. 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

  10. Cell resolved, multiparticle model of plastic tissue deformations and morphogenesis

    CERN Document Server

    Czirok, Andras

    2014-01-01

    We propose a three dimensional mechanical model of embryonic tissue dynamics. Mechanically coupled adherent cells are represented as particles interconnected with elastic beams which can exert non-central forces and torques. Tissue plasticity is modeled by a stochastic process consisting of a connectivity change (addition or removal of a single link) followed by a complete relaxation to mechanical equilibrium. In particular, we assume that (i) two non-connected, but adjacent particles can form a new link; and (ii) the lifetime of links is reduced by tensile forces. We demonstrate that the proposed model yields a realistic macroscopic elasto-plastic behavior and we establish how microscopic model parameters affect the material properties at the macroscopic scale. Based on these results, microscopic parameter values can be inferred from tissue thickness, macroscopic elastic modulus and the magnitude and dynamics of intercellular adhesion forces. In addition to their mechanical role, model particles can also act...

  11. Auto-Populating an ILL form with the Serial Solutions Link Resolver API

    OpenAIRE

    Daniel Talsky

    2008-01-01

    In this article we'll take a tour of the OpenURL protocol; discover how to use it to get an XML API response from the Serial Solutions link resolver; and see how to receive and process that XML data using PHP to create an Interlibrary Loan webform. Finally, we'll see a few examples of how to handle form processing. This article will be of interest to beginner programmers interested in examples of programming with OpenURL and XML in PHP, and to more experienced programmers interested in taking...

  12. Auto-Populating an ILL form with the Serial Solutions Link Resolver API

    Directory of Open Access Journals (Sweden)

    Daniel Talsky

    2008-09-01

    Full Text Available In this article we'll take a tour of the OpenURL protocol; discover how to use it to get an XML API response from the Serial Solutions link resolver; and see how to receive and process that XML data using PHP to create an Interlibrary Loan webform. Finally, we'll see a few examples of how to handle form processing. This article will be of interest to beginner programmers interested in examples of programming with OpenURL and XML in PHP, and to more experienced programmers interested in taking a look at the Serial Solutions 360 Link API.

  13. Mechanical properties of single cells by high-frequency time-resolved acoustic microscopy.

    Science.gov (United States)

    Weiss, Eike C; Anastasiadis, Pavlos; Pilarczyk, Götz; Lemor, Robert M; Zinin, Pavel V

    2007-11-01

    In this paper, we describe a new, high-frequency, time-resolved scanning acoustic microscope developed for studying dynamical processes in biological cells. The new acoustic microscope operates in a time-resolved mode. The center frequency is 0.86 GHz, and the pulse duration is 5 ns. With such a short pulse, layers thicker than 3 microm can be resolved. For a cell thicker than 3 microm, the front echo and the echo from the substrate can be distinguished in the signal. Positions of the first and second pulses are used to determine the local impedance of the cell modeled as a thin liquid layer that has spatial variations in its elastic properties. The low signal-to-noise ratio in the acoustical images is increased for image generation by averaging the detected radio frequency signal over 10 measurements at each scanning point. In conducting quantitative measurements of the acoustic parameters of cells, the signal can be averaged over 2000 measurements. This approach enables us to measure acoustical properties of a single HeLa cell in vivo and to derive elastic parameters of subcellular structures. The value of the sound velocity inside the cell (1534.5 +/- 33.6 m/s) appears to be only slightly higher than that of the cell medium (1501 m/s). PMID:18051160

  14. Detecting cell assemblies in large neuronal populations.

    Science.gov (United States)

    Lopes-dos-Santos, Vítor; Ribeiro, Sidarta; Tort, Adriano B L

    2013-11-15

    Recent progress in the technology for single unit recordings has given the neuroscientific community the opportunity to record the spiking activity of large neuronal populations. At the same pace, statistical and mathematical tools were developed to deal with high-dimensional datasets typical of such recordings. A major line of research investigates the functional role of subsets of neurons with significant co-firing behavior: the Hebbian cell assemblies. Here we review three linear methods for the detection of cell assemblies in large neuronal populations that rely on principal and independent component analysis. Based on their performance in spike train simulations, we propose a modified framework that incorporates multiple features of these previous methods. We apply the new framework to actual single unit recordings and show the existence of cell assemblies in the rat hippocampus, which typically oscillate at theta frequencies and couple to different phases of the underlying field rhythm. PMID:23639919

  15. Circadian rhythm and cell population growth

    CERN Document Server

    Clairambault, Jean; Lepoutre, Thomas

    2010-01-01

    Molecular circadian clocks, that are found in all nucleated cells of mammals, are known to dictate rhythms of approximately 24 hours (circa diem) to many physiological processes. This includes metabolism (e.g., temperature, hormonal blood levels) and cell proliferation. It has been observed in tumor-bearing laboratory rodents that a severe disruption of these physiological rhythms results in accelerated tumor growth. The question of accurately representing the control exerted by circadian clocks on healthy and tumour tissue proliferation to explain this phenomenon has given rise to mathematical developments, which we review. The main goal of these previous works was to examine the influence of a periodic control on the cell division cycle in physiologically structured cell populations, comparing the effects of periodic control with no control, and of different periodic controls between them. We state here a general convexity result that may give a theoretical justification to the concept of cancer chronothera...

  16. A Structured Population Model of Cell Differentiation

    CERN Document Server

    Doumic, Marie; Perthame, Benoit; Zubelli, Jorge P

    2010-01-01

    We introduce and analyze several aspects of a new model for cell differentiation. It assumes that differentiation of progenitor cells is a continuous process. From the mathematical point of view, it is based on partial differential equations of transport type. Specifically, it consists of a structured population equation with a nonlinear feedback loop. This models the signaling process due to cytokines, which regulate the differentiation and proliferation process. We compare the continuous model to its discrete counterpart, a multi-compartmental model of a discrete collection of cell subpopulations recently proposed by Marciniak-Czochra et al. in 2009 to investigate the dynamics of the hematopoietic system. We obtain uniform bounds for the solutions, characterize steady state solutions, and analyze their linearized stability. We show how persistence or extinction might occur according to values of parameters that characterize the stem cells self-renewal. We also perform numerical simulations and discuss the q...

  17. Genomic evidence for island population conversion resolves conflicting theories of polar bear evolution.

    Science.gov (United States)

    Cahill, James A; Green, Richard E; Fulton, Tara L; Stiller, Mathias; Jay, Flora; Ovsyanikov, Nikita; Salamzade, Rauf; St John, John; Stirling, Ian; Slatkin, Montgomery; Shapiro, Beth

    2013-01-01

    Despite extensive genetic analysis, the evolutionary relationship between polar bears (Ursus maritimus) and brown bears (U. arctos) remains unclear. The two most recent comprehensive reports indicate a recent divergence with little subsequent admixture or a much more ancient divergence followed by extensive admixture. At the center of this controversy are the Alaskan ABC Islands brown bears that show evidence of shared ancestry with polar bears. We present an analysis of genome-wide sequence data for seven polar bears, one ABC Islands brown bear, one mainland Alaskan brown bear, and a black bear (U. americanus), plus recently published datasets from other bears. Surprisingly, we find clear evidence for gene flow from polar bears into ABC Islands brown bears but no evidence of gene flow from brown bears into polar bears. Importantly, while polar bears contributed <1% of the autosomal genome of the ABC Islands brown bear, they contributed 6.5% of the X chromosome. The magnitude of sex-biased polar bear ancestry and the clear direction of gene flow suggest a model wherein the enigmatic ABC Island brown bears are the descendants of a polar bear population that was gradually converted into brown bears via male-dominated brown bear admixture. We present a model that reconciles heretofore conflicting genetic observations. We posit that the enigmatic ABC Islands brown bears derive from a population of polar bears likely stranded by the receding ice at the end of the last glacial period. Since then, male brown bear migration onto the island has gradually converted these bears into an admixed population whose phenotype and genotype are principally brown bear, except at mtDNA and X-linked loci. This process of genome erosion and conversion may be a common outcome when climate change or other forces cause a population to become isolated and then overrun by species with which it can hybridize. PMID:23516372

  18. Genomic Evidence for Island Population Conversion Resolves Conflicting Theories of Polar Bear Evolution

    Science.gov (United States)

    Cahill, James A.; Green, Richard E.; Fulton, Tara L.; Stiller, Mathias; Jay, Flora; Ovsyanikov, Nikita; Salamzade, Rauf; St. John, John; Stirling, Ian; Slatkin, Montgomery; Shapiro, Beth

    2013-01-01

    Despite extensive genetic analysis, the evolutionary relationship between polar bears (Ursus maritimus) and brown bears (U. arctos) remains unclear. The two most recent comprehensive reports indicate a recent divergence with little subsequent admixture or a much more ancient divergence followed by extensive admixture. At the center of this controversy are the Alaskan ABC Islands brown bears that show evidence of shared ancestry with polar bears. We present an analysis of genome-wide sequence data for seven polar bears, one ABC Islands brown bear, one mainland Alaskan brown bear, and a black bear (U. americanus), plus recently published datasets from other bears. Surprisingly, we find clear evidence for gene flow from polar bears into ABC Islands brown bears but no evidence of gene flow from brown bears into polar bears. Importantly, while polar bears contributed <1% of the autosomal genome of the ABC Islands brown bear, they contributed 6.5% of the X chromosome. The magnitude of sex-biased polar bear ancestry and the clear direction of gene flow suggest a model wherein the enigmatic ABC Island brown bears are the descendants of a polar bear population that was gradually converted into brown bears via male-dominated brown bear admixture. We present a model that reconciles heretofore conflicting genetic observations. We posit that the enigmatic ABC Islands brown bears derive from a population of polar bears likely stranded by the receding ice at the end of the last glacial period. Since then, male brown bear migration onto the island has gradually converted these bears into an admixed population whose phenotype and genotype are principally brown bear, except at mtDNA and X-linked loci. This process of genome erosion and conversion may be a common outcome when climate change or other forces cause a population to become isolated and then overrun by species with which it can hybridize. PMID:23516372

  19. Genomic evidence for island population conversion resolves conflicting theories of polar bear evolution.

    Directory of Open Access Journals (Sweden)

    James A Cahill

    Full Text Available Despite extensive genetic analysis, the evolutionary relationship between polar bears (Ursus maritimus and brown bears (U. arctos remains unclear. The two most recent comprehensive reports indicate a recent divergence with little subsequent admixture or a much more ancient divergence followed by extensive admixture. At the center of this controversy are the Alaskan ABC Islands brown bears that show evidence of shared ancestry with polar bears. We present an analysis of genome-wide sequence data for seven polar bears, one ABC Islands brown bear, one mainland Alaskan brown bear, and a black bear (U. americanus, plus recently published datasets from other bears. Surprisingly, we find clear evidence for gene flow from polar bears into ABC Islands brown bears but no evidence of gene flow from brown bears into polar bears. Importantly, while polar bears contributed <1% of the autosomal genome of the ABC Islands brown bear, they contributed 6.5% of the X chromosome. The magnitude of sex-biased polar bear ancestry and the clear direction of gene flow suggest a model wherein the enigmatic ABC Island brown bears are the descendants of a polar bear population that was gradually converted into brown bears via male-dominated brown bear admixture. We present a model that reconciles heretofore conflicting genetic observations. We posit that the enigmatic ABC Islands brown bears derive from a population of polar bears likely stranded by the receding ice at the end of the last glacial period. Since then, male brown bear migration onto the island has gradually converted these bears into an admixed population whose phenotype and genotype are principally brown bear, except at mtDNA and X-linked loci. This process of genome erosion and conversion may be a common outcome when climate change or other forces cause a population to become isolated and then overrun by species with which it can hybridize.

  20. Resolved HI Imaging of a Population of Massive HI-Rich Galaxies with Suppressed Star Formation

    OpenAIRE

    Lemonias, Jenna J.; Schiminovich, David; Catinella, Barbara; Heckman, Timothy M.; Moran, Sean M.

    2014-01-01

    Despite the existence of well-defined relationships between cold gas and star formation, there is evidence that some galaxies contain large amounts of HI that do not form stars efficiently. By systematically assessing the link between HI and star formation within a sample of galaxies with extremely high HI masses (log M_HI/M_sun > 10), we uncover a population of galaxies with an unexpected combination of high HI masses and low specific star formation rates that exists primarily at stellar mas...

  1. Characterization and localization of side population cells in the lens

    OpenAIRE

    Oka, Mikako; Toyoda, Chizuko; Kaneko, Yuka; Nakazawa, Yosuke; Aizu-Yokota, Eriko; Takehana, Makoto

    2010-01-01

    Purpose Side population (SP) cells were isolated and the possibility whether lens epithelial cells contain stem cells was investigated. Methods Mouse lens epithelial cells were stained by Hoechst 33342 and then sorted by fluorescence-activated cell sorting (FACS). The expression of stem cell markers in sorted SP cells and the main population of epithelial cells were analyzed by quantitative real-time PCR. Localization of SP cells in the mouse lens was studied by fluorescence microscopy. Resul...

  2. PMAS Optical Integral Field Spectroscopy of Luminous Infrared Galaxies. II.-- Spatially resolved stellar populations and excitation conditions

    CERN Document Server

    Alonso-Herrero, Almudena; Zaurin, Javier Rodriguez; Monreal-Ibero, Ana; Colina, Luis; Arribas, Santiago

    2010-01-01

    The general properties of luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs) in the local universe are well known since large samples of these objects have been the subject of numerous spectroscopic works. There are, however, relatively few studies of large samples of LIRGs and ULIRGs using integral field spectroscopy (IFS). We analyze optical (3800-7200A) IFS data taken with the Potsdam Multi-Aperture Spectrophotometer (PMAS) of the central few kiloparsecs of 11 LIRGs. To study the stellar populations we fit the optical stellar continuum and the hydrogen recombination lines of selected regions. We analyze the excitation conditions of the gas using the spatially resolved properties of the brightest optical emission lines. The optical continua of the selected regions are well fitted with a combination of evolved (~0.7-10Gyr) and ionizing (1-20Myr) stellar populations. The latter is more obscured than the evolved population, and has visual extinctions in good agreement with those obtained from the ...

  3. The CALIFA survey across the Hubble sequence: Spatially resolved stellar population properties in galaxies

    CERN Document Server

    Delgado, R M González; Pérez, E; Fernandes, R Cid; de Amorim, A L; Cortijo-Ferrero, C; Lacerda, E A D; Fernández, R López; Vale-Asari, N; Sánchez, S F; Mollá, M; Ruiz-Lara, T; Sánchez-Blázquez, P; Walcher, C J; Alves, J; Aguerri, J A L; Bekeraité, S; Bland-Hawthorn, J; Galbany, L; Gallazzi, A; Husemann, B; Iglesias-Páramo, J; Kalinova, V; López-Sánchez, A R; Marino, R A; Márquez, I; Masegosa, J; Mast, D; Méndez-Abreu, J; Mendoza, A; del Olmo, A; Pérez, I; Quirrenbach, A; Zibetti, S

    2015-01-01

    This paper characterizes the radial structure of stellar population properties of galaxies in the nearby universe, based on 300 galaxies from the CALIFA survey. The sample covers a wide range of Hubble types, and galaxy stellar mass. We apply the spectral synthesis techniques to recover the stellar mass surface density, stellar extinction, light and mass-weighted ages, and mass-weighted metallicity, for each spatial resolution element in our target galaxies. To study mean trends with overall galaxy properties, the individual radial profiles are stacked in seven bins of galaxy morphology. We confirm that more massive galaxies are more compact, older, more metal rich, and less reddened by dust. Additionally, we find that these trends are preserved spatially with the radial distance to the nucleus. Deviations from these relations appear correlated with Hubble type: earlier types are more compact, older, and more metal rich for a given mass, which evidences that quenching is related to morphology, but not driven ...

  4. Resolution of Two Sub-Populations of Conformers and Their Individual Dynamics by Time Resolved Ensemble Level FRET Measurements.

    Directory of Open Access Journals (Sweden)

    Gil Rahamim

    Full Text Available Most active biopolymers are dynamic structures; thus, ensembles of such molecules should be characterized by distributions of intra- or intermolecular distances and their fast fluctuations. A method of choice to determine intramolecular distances is based on Förster resonance energy transfer (FRET measurements. Major advances in such measurements were achieved by single molecule FRET measurements. Here, we show that by global analysis of the decay of the emission of both the donor and the acceptor it is also possible to resolve two sub-populations in a mixture of two ensembles of biopolymers by time resolved FRET (trFRET measurements at the ensemble level. We show that two individual intramolecular distance distributions can be determined and characterized in terms of their individual means, full width at half maximum (FWHM, and two corresponding diffusion coefficients which reflect the rates of fast ns fluctuations within each sub-population. An important advantage of the ensemble level trFRET measurements is the ability to use low molecular weight small-sized probes and to determine nanosecond fluctuations of the distance between the probes. The limits of the possible resolution were first tested by simulation and then by preparation of mixtures of two model peptides. The first labeled polypeptide was a relatively rigid Pro7 and the second polypeptide was a flexible molecule consisting of (Gly-Ser7 repeats. The end to end distance distributions and the diffusion coefficients of each peptide were determined. Global analysis of trFRET measurements of a series of mixtures of polypeptides recovered two end-to-end distance distributions and associated intramolecular diffusion coefficients, which were very close to those determined from each of the pure samples. This study is a proof of concept study demonstrating the power of ensemble level trFRET based methods in resolution of subpopulations in ensembles of flexible macromolecules.

  5. Evaluation of a spatially resolved forest fire smoke model for population-based epidemiologic exposure assessment.

    Science.gov (United States)

    Yao, Jiayun; Eyamie, Jeff; Henderson, Sarah B

    2016-05-01

    Exposure to forest fire smoke (FFS) is associated with multiple adverse health effects, mostly respiratory. Findings for cardiovascular effects have been inconsistent, possibly related to the limitations of conventional methods to assess FFS exposure. In previous work, we developed an empirical model to estimate smoke-related fine particulate matter (PM2.5) for all populated areas in British Columbia (BC), Canada. Here, we evaluate the utility of our model by comparing epidemiologic associations between modeled and measured PM2.5. For each local health area (LHA), we used Poisson regression to estimate the effects of PM2.5 estimates and measurements on counts of medication dispensations and outpatient physician visits. We then used meta-regression to estimate the overall effects. A 10 μg/m(3) increase in modeled PM2.5 was associated with increased sabutamol dispensations (RR=1.04, 95% CI 1.03-1.06), and physician visits for asthma (1.06, 1.04-1.08), COPD (1.02, 1.00-1.03), lower respiratory infections (1.03, 1.00-1.05), and otitis media (1.05, 1.03-1.07), all comparable to measured PM2.5. Effects on cardiovascular outcomes were only significant using model estimates in all LHAs during extreme fire days. This suggests that the exposure model is a promising tool for increasing the power of epidemiologic studies to detect the health effects of FFS via improved spatial coverage and resolution. PMID:25294305

  6. Quantitative multicolor compositional imaging resolves molecular domains in cell-matrix adhesions.

    Directory of Open Access Journals (Sweden)

    Eli Zamir

    Full Text Available BACKGROUND: Cellular processes occur within dynamic and multi-molecular compartments whose characterization requires analysis at high spatio-temporal resolution. Notable examples for such complexes are cell-matrix adhesion sites, consisting of numerous cytoskeletal and signaling proteins. These adhesions are highly variable in their morphology, dynamics, and apparent function, yet their molecular diversity is poorly defined. METHODOLOGY/PRINCIPAL FINDINGS: We present here a compositional imaging approach for the analysis and display of multi-component compositions. This methodology is based on microscopy-acquired multicolor data, multi-dimensional clustering of pixels according to their composition similarity and display of the cellular distribution of these composition clusters. We apply this approach for resolving the molecular complexes associated with focal-adhesions, and the time-dependent effects of Rho-kinase inhibition. We show here compositional variations between adhesion sites, as well as ordered variations along the axis of individual focal-adhesions. The multicolor clustering approach also reveals distinct sensitivities of different focal-adhesion-associated complexes to Rho-kinase inhibition. CONCLUSIONS/SIGNIFICANCE: Multicolor compositional imaging resolves "molecular signatures" characteristic to focal-adhesions and related structures, as well as sub-domains within these adhesion sites. This analysis enhances the spatial information with additional "contents-resolved" dimensions. We propose that compositional imaging can serve as a powerful tool for studying complex multi-molecular assemblies in cells and for mapping their distribution at sub-micron resolution.

  7. Time- and polarization-resolved cellular autofluorescence towards quantitative biochemistry on living cells

    Science.gov (United States)

    Alfveby, John; TImerman, Randi; Soto Velasquez, Monica P.; Wickramasinghe, Dhanushka W. P. M.; Bartusek, Jillian; Heikal, Ahmed A.

    2014-09-01

    Native coenzymes such as the reduced nicotinamide adenine dinucleotide (NADH) and oxidized flavin adenine dinucleotide play pivotal roles in energy metabolism and a myriad of biochemical reactions in living cells/tissues. These coenzymes are naturally fluorescent and, therefore, have the potential to serve as intrinsic biomarkers for mitochondrial activities, programmed cell death (apoptosis), oxidative stress, aging, and neurodegenerative disease. In this contribution, we employ two-photon fluorescence lifetime imaging microscopy (FLIM) and time-resolved anisotropy imaging of intracellular NADH for quantitative, non-invasive biochemistry on living cells in response to hydrogenperoxide- induced oxidative stress. In contrast with steady-state one-photon, UV-excited autofluorescence, two-photon FLIM is sensitive to both molecular conformation and stimuli-induced changes in the local environment in living cells with minimum photodamage and inherently enhanced spatial resolution. On the other hand, time-resolved, two-photon anisotropy imaging of cellular autofluorescence allows for quantitative assessment of binding state and environmental restrictions on the tumbling mobility of intrinsic NADH. Our measurements reveal that free and enzyme-bound NADH exist at equilibrium, with a dominant autofluorescence contribution of the bound fraction in living cells. Parallel studies on NADH-enzyme binding in controlled environments serve as a point of reference in analyzing autofluorescence in living cells. These autofluorescence-based approaches complement the conventional analytical biochemistry methods that require the destruction of cells/tissues, while serving as an important step towards establishing intracellular NADH as a natural biomarker for monitoring changes in energy metabolism and redox state of living cells in response to environmental hazards.

  8. Comparative study of photoreceptor and retinal ganglion cell topography and spatial resolving power in Dipsadidae snakes.

    Science.gov (United States)

    Hauzman, Einat; Bonci, Daniela M O; Grotzner, Sonia R; Mela, Maritana; Liber, André M P; Martins, Sonia L; Ventura, Dora F

    2014-01-01

    The diurnal Dipsadidae snakes Philodryas olfersii and P. patagoniensis are closely related in their phylogeny but inhabit different ecological niches. P. olfersii is arboreal, whereas P. patagoniensis is preferentially terrestrial. The goal of the present study was to compare the density and topography of neurons, photoreceptors, and cells in the ganglion cell layer in the retinas of these two species using immunohistochemistry and Nissl staining procedures and estimate the spatial resolving power of their eyes based on the ganglion cell peak density. Four morphologically distinct types of cones were observed by scanning electron microscopy, 3 of which were labeled with anti-opsin antibodies: large single cones and double cones labeled by the antibody JH492 and small single cones labeled by the antibody JH455. The average densities of photoreceptors and neurons in the ganglion cell layer were similar in both species (∼10,000 and 7,000 cells·mm(-2), respectively). The estimated spatial resolving power was also similar, ranging from 2.4 to 2.7 cycles·degree(-1). However, the distribution of neurons had different specializations. In the arboreal P. olfersii, the isodensity maps had a horizontal visual streak, with a peak density in the central region and a lower density in the dorsal retina. This organization might be relevant for locomotion and hunting behavior in the arboreal layer. In the terrestrial P. patagoniensis, a concentric pattern of decreasing cell density emanated from an area centralis located in the naso-ventral retina. Lower densities were observed in the dorsal region. The ventrally high density improves the resolution in the superior visual field and may be an important adaptation for terrestrial snakes to perceive the approach of predators from above. PMID:25342570

  9. High prevalence of side population in human cancer cell lines

    OpenAIRE

    Boesch, Maximilian; Zeimet, Alain G; Fiegl, Heidi; Wolf, Barbara; Huber, Julia; Klocker, Helmut; Gastl, Guenther; Sopper, Sieghart; Wolf, Dominik

    2016-01-01

    Cancer cell lines are essential platforms for performing cancer research on human cells. We here demonstrate that, across tumor entities, human cancer cell lines harbor minority populations of putative stem-like cells, molecularly defined by dye extrusion resulting in the side population phenotype. These findings establish a heterogeneous nature of human cancer cell lines and argue for their stem cell origin. This should be considered when interpreting research involving these model systems.

  10. 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...

  11. THE RESOLVED STELLAR POPULATION IN 50 REGIONS OF M83 FROM HST/WFC3 EARLY RELEASE SCIENCE OBSERVATIONS

    International Nuclear Information System (INIS)

    We present a multi-wavelength photometric study of ∼15,000 resolved stars in the nearby spiral galaxy M83 (NGC 5236, D = 4.61 Mpc) based on Hubble Space Telescope Wide Field Camera 3 observations using four filters: F336W, F438W, F555W, and F814W. We select 50 regions (an average size of 260 pc by 280 pc) in the spiral arm and inter-arm areas of M83 and determine the age distribution of the luminous stellar populations in each region. This is accomplished by correcting for extinction toward each individual star by comparing its colors with predictions from stellar isochrones. We compare the resulting luminosity-weighted mean ages of the luminous stars in the 50 regions with those determined from several independent methods, including the number ratio of red-to-blue supergiants, morphological appearance of the regions, surface brightness fluctuations, and the ages of clusters in the regions. We find reasonably good agreement between these methods. We also find that young stars are much more likely to be found in concentrated aggregates along spiral arms, while older stars are more dispersed. These results are consistent with the scenario that star formation is associated with the spiral arms, and stars form primarily in star clusters and then disperse on short timescales to form the field population. The locations of Wolf-Rayet stars are found to correlate with the positions of many of the youngest regions, providing additional support for our ability to accurately estimate ages. We address the effects of spatial resolution on the measured colors, magnitudes, and age estimates. While individual stars can occasionally show measurable differences in the colors and magnitudes, the age estimates for entire regions are only slightly affected.

  12. THE RESOLVED STELLAR POPULATION IN 50 REGIONS OF M83 FROM HST/WFC3 EARLY RELEASE SCIENCE OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hwihyun; Cohen, Seth H.; Windhorst, Rogier A. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404 (United States); Whitmore, Bradley C.; Mutchler, Max; Bond, Howard E. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Chandar, Rupali [Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States); Saha, Abhijit [National Optical Astronomy Observatories, Tucson, AZ 85726-6732 (United States); Kaleida, Catherine C. [Cerro Tololo Inter-American Observatory, La Serena (Chile); Calzetti, Daniela [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); O' Connell, Robert W. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States); Balick, Bruce [Department of Astronomy, University of Washington, Seattle, WA 98195-1580 (United States); Carollo, Marcella [Department of Physics, ETH-Zurich, Zurich 8093 (Switzerland); Disney, Michael J. [School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom); Dopita, Michael A. [Mount Stromlo and Siding Spring Observatories, Research School of Astronomy and Astrophysics, Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia); Frogel, Jay A. [Galaxies Unlimited, 1 Tremblant Court, Lutherville, MD 21093 (United States); Hall, Donald N. B. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Holtzman, Jon A. [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States); Kimble, Randy A. [NASA-Goddard Space Flight Center, Greenbelt, MD 20771 (United States); McCarthy, Patrick J., E-mail: hwihyun.kim@asu.edu [Observatories of the Carnegie Institution of Washington, Pasadena, CA 91101-1292 (United States); and others

    2012-07-01

    We present a multi-wavelength photometric study of {approx}15,000 resolved stars in the nearby spiral galaxy M83 (NGC 5236, D = 4.61 Mpc) based on Hubble Space Telescope Wide Field Camera 3 observations using four filters: F336W, F438W, F555W, and F814W. We select 50 regions (an average size of 260 pc by 280 pc) in the spiral arm and inter-arm areas of M83 and determine the age distribution of the luminous stellar populations in each region. This is accomplished by correcting for extinction toward each individual star by comparing its colors with predictions from stellar isochrones. We compare the resulting luminosity-weighted mean ages of the luminous stars in the 50 regions with those determined from several independent methods, including the number ratio of red-to-blue supergiants, morphological appearance of the regions, surface brightness fluctuations, and the ages of clusters in the regions. We find reasonably good agreement between these methods. We also find that young stars are much more likely to be found in concentrated aggregates along spiral arms, while older stars are more dispersed. These results are consistent with the scenario that star formation is associated with the spiral arms, and stars form primarily in star clusters and then disperse on short timescales to form the field population. The locations of Wolf-Rayet stars are found to correlate with the positions of many of the youngest regions, providing additional support for our ability to accurately estimate ages. We address the effects of spatial resolution on the measured colors, magnitudes, and age estimates. While individual stars can occasionally show measurable differences in the colors and magnitudes, the age estimates for entire regions are only slightly affected.

  13. The Resolved Stellar Population in 50 Regions of M83 from HST/WFC3 Early Release Science Observations

    Science.gov (United States)

    Kim, Hwihyun; Whitmore, Bradley C.; Chandar, Rupali; Saha, Abhijit; Kaleida, Catherine C.; Mutchler, Max; Cohen, Seth H.; Calzetti, Daniela; O’Connell, Robert W.; Windhorst, Rogier A.; Balick, Bruce; Bond, Howard E.; Carollo, Marcella; Disney, Michael J.; Dopita, Michael A.; Frogel, Jay A.; Hall, Donald N. B.; Holtzman, Jon A.; Kimble, Randy A.; McCarthy, Patrick J.; Paresce, Francesco; Silk, Joe I; Trauger, John T.; Walker, Alistair R.; Young, Erick T.

    2012-01-01

    We present a multi-wavelength photometric study of approximately 15,000 resolved stars in the nearby spiral galaxy M83 (NGC 5236, D = 4.61 Mpc) based on Hubble Space Telescope Wide Field Camera 3 observations using four filters: F336W, F438W, F555W, and F814W. We select 50 regions (an average size of 260 pc by 280 pc) in the spiral arm and inter-arm areas of M83 and determine the age distribution of the luminous stellar populations in each region. This is accomplished by correcting for extinction toward each individual star by comparing its colors with predictions from stellar isochrones.We compare the resulting luminosity-weighted mean ages of the luminous stars in the 50 regions with those determined from several independent methods, including the number ratio of red-to-blue supergiants, morphological appearance of the regions, surface brightness fluctuations, and the ages of clusters in the regions. We find reasonably good agreement between these methods. We also find that young stars are much more likely to be found in concentrated aggregates along spiral arms, while older stars are more dispersed. These results are consistent with the scenario that star formation is associated with the spiral arms, and stars form primarily in star clusters and then disperse on short timescales to form the field population. The locations ofWolf-Rayet stars are found to correlate with the positions of many of the youngest regions, providing additional support for our ability to accurately estimate ages. We address the effects of spatial resolution on the measured colors, magnitudes, and age estimates. While individual stars can occasionally show measurable differences in the colors and magnitudes, the age estimates for entire regions are only slightly affected.

  14. The Resolved Stellar Population in 50 Regions of M83 from HST/WFC3 Early Release Science Observations

    CERN Document Server

    Kim, Hwihyun; Chandar, Rupali; Saha, Abhijit; Kaleida, Catherine C; Mutchler, Max; Cohen, Seth H; Calzetti, Daniela; O'Connell, Robert W; Windhorst, Rogier A; Balick, Bruce; Bond, Howard E; Carollo, C Marcella; Disney, Michael J; Dopita, Michael A; Frogel, Jay A; Hall, Donald N B; Holtzman, Jon A; Kimble, Randy A; McCarthy, Patrick J; Paresce, Francesco; Silk, Joe I; Trauger, John T; Walker, Alistair R; Young, Erick T

    2012-01-01

    We present a multi-wavelength photometric study of ~15,000 resolved stars in the nearby spiral galaxy M83 (NGC5236, D=4.61Mpc) based on Hubble Space Telescope Wide Field Camera 3 observations using four filters: F336W, F438W, F555W, and F814W. We select 50 regions (an average size of 260 pc by 280 pc) in the spiral arm and inter-arm areas of M83, and determine the age distribution of the luminous stellar populations in each region. This is accomplished by correcting for extinction towards each individual star by comparing its colors with predictions from stellar isochrones. We compare the resulting luminosity weighted mean ages of the luminous stars in the 50 regions with those determined from several independent methods, including the number ratio of red-to-blue supergiants, morphological appearance of the regions, surface brightness fluctuations, and the ages of clusters in the regions. We find reasonably good agreement between these methods. We also find that young stars are much more likely to be found in...

  15. Time-resolved NMR metabolomics of plant cells based on a microfluidic chip.

    Science.gov (United States)

    Maisch, Jan; Kreppenhofer, Kristina; Büchler, Silke; Merle, Christian; Sobich, Shukhrat; Görling, Benjamin; Luy, Burkhard; Ahrens, Ralf; Guber, Andreas E; Nick, Peter

    2016-08-01

    The plant secondary metabolism generates numerous compounds harbouring pharmaceutical activity. In plants, these compounds are typically formed by different and specialised cell types that have to interact constituting a metabolic process chain. This interactivity impedes biotechnological production of secondary compounds, because cell differentiation is suppressed under the conditions of a batch bio-fermenter. We present a novel strategy to address this limitation using a biomimetic approach, where we simulate the situation in a real tissue by a microfluidic chamber system, where plant cells can be integrated into a process flow. We show that walled cells of the plant model tobacco BY-2 can be successfully cultivated in this system and that physiological parameters (such as cell viability, mitotic index and division synchrony) can be preserved over several days. The microfluidic design allows to resolve dynamic changes of specific metabolites over different stages of culture development. These results serve as proof-of-principle that a microfluidic organisation of cultivated plant cells can mimic the metabolic flows in a real plant tissue. PMID:27318870

  16. A homogeneous time-resolved fluorescence resonance energy transfer assay for phosphatidylserine exposure on apoptotic cells.

    Science.gov (United States)

    Gasser, Jean-Philippe; Hehl, Michaela; Millward, Thomas A

    2009-01-01

    A simple, "mix-and-measure" microplate assay for phosphatidylserine (PtdSer) exposure on the surface of apoptotic cells is described. The assay exploits the fact that annexin V, a protein with high affinity and specificity for PtdSer, forms trimers and higher order oligomers on binding to membranes containing PtdSer. The transition from soluble monomer to cell-bound oligomer is detected using time-resolved fluorescence resonance energy transfer from europium chelate-labeled annexin V to Cy5-labeled annexin V. PtdSer detection is achieved by a single addition of a reagent mix containing labeled annexins and calcium ions directly to cell cultures in a 96-well plate, followed by a brief incubation before fluorescence measurement. The assay can be used to quantify PtdSer exposure on both suspension cells and adherent cells in situ. This method is simpler and faster than existing annexin V binding assays based on flow cytometry or microscopy, and it yields precise data with Z' values of 0.6-0.7. PMID:18835236

  17. Single-Cell Phosphoproteomics Resolves Adaptive Signaling Dynamics and Informs Targeted Combination Therapy in Glioblastoma.

    Science.gov (United States)

    Wei, Wei; Shin, Young Shik; Xue, Min; Matsutani, Tomoo; Masui, Kenta; Yang, Huijun; Ikegami, Shiro; Gu, Yuchao; Herrmann, Ken; Johnson, Dazy; Ding, Xiangming; Hwang, Kiwook; Kim, Jungwoo; Zhou, Jian; Su, Yapeng; Li, Xinmin; Bonetti, Bruno; Chopra, Rajesh; James, C David; Cavenee, Webster K; Cloughesy, Timothy F; Mischel, Paul S; Heath, James R; Gini, Beatrice

    2016-04-11

    Intratumoral heterogeneity of signaling networks may contribute to targeted cancer therapy resistance, including in the highly lethal brain cancer glioblastoma (GBM). We performed single-cell phosphoproteomics on a patient-derived in vivo GBM model of mTOR kinase inhibitor resistance and coupled it to an analytical approach for detecting changes in signaling coordination. Alterations in the protein signaling coordination were resolved as early as 2.5 days after treatment, anticipating drug resistance long before it was clinically manifest. Combination therapies were identified that resulted in complete and sustained tumor suppression in vivo. This approach may identify actionable alterations in signal coordination that underlie adaptive resistance, which can be suppressed through combination drug therapy, including non-obvious drug combinations. PMID:27070703

  18. Time-Resolved Imaging of Single HIV-1 Uncoating In Vitro and in Living Cells.

    Science.gov (United States)

    Francis, Ashwanth C; Marin, Mariana; Shi, Jiong; Aiken, Christopher; Melikyan, Gregory B

    2016-06-01

    Disassembly of the cone-shaped HIV-1 capsid in target cells is a prerequisite for establishing a life-long infection. This step in HIV-1 entry, referred to as uncoating, is critical yet poorly understood. Here we report a novel strategy to visualize HIV-1 uncoating using a fluorescently tagged oligomeric form of a capsid-binding host protein cyclophilin A (CypA-DsRed), which is specifically packaged into virions through the high-avidity binding to capsid (CA). Single virus imaging reveals that CypA-DsRed remains associated with cores after permeabilization/removal of the viral membrane and that CypA-DsRed and CA are lost concomitantly from the cores in vitro and in living cells. The rate of loss is modulated by the core stability and is accelerated upon the initiation of reverse transcription. We show that the majority of single cores lose CypA-DsRed shortly after viral fusion, while a small fraction remains intact for several hours. Single particle tracking at late times post-infection reveals a gradual loss of CypA-DsRed which is dependent on reverse transcription. Uncoating occurs both in the cytoplasm and at the nuclear membrane. Our novel imaging assay thus enables time-resolved visualization of single HIV-1 uncoating in living cells, and reveals the previously unappreciated spatio-temporal features of this incompletely understood process. PMID:27322072

  19. What's new is old: resolving the identity of Leptothrix ochracea using single cell genomics, pyrosequencing and FISH.

    Directory of Open Access Journals (Sweden)

    Emily J Fleming

    Full Text Available Leptothrix ochracea is a common inhabitant of freshwater iron seeps and iron-rich wetlands. Its defining characteristic is copious production of extracellular sheaths encrusted with iron oxyhydroxides. Surprisingly, over 90% of these sheaths are empty, hence, what appears to be an abundant population of iron-oxidizing bacteria, consists of relatively few cells. Because L. ochracea has proven difficult to cultivate, its identification is based solely on habitat preference and morphology. We utilized cultivation-independent techniques to resolve this long-standing enigma. By selecting the actively growing edge of a Leptothrix-containing iron mat, a conventional SSU rRNA gene clone library was obtained that had 29 clones (42% of the total library related to the Leptothrix/Sphaerotilus group (≤96% identical to cultured representatives. A pyrotagged library of the V4 hypervariable region constructed from the bulk mat showed that 7.2% of the total sequences also belonged to the Leptothrix/Sphaerotilus group. Sorting of individual L. ochracea sheaths, followed by whole genome amplification (WGA and PCR identified a SSU rRNA sequence that clustered closely with the putative Leptothrix clones and pyrotags. Using these data, a fluorescence in-situ hybridization (FISH probe, Lepto175, was designed that bound to ensheathed cells. Quantitative use of this probe demonstrated that up to 35% of microbial cells in an actively accreting iron mat were L. ochracea. The SSU rRNA gene of L. ochracea shares 96% homology with its closet cultivated relative, L. cholodnii, This establishes that L. ochracea is indeed related to this group of morphologically similar, filamentous, sheathed microorganisms.

  20. Targeting population heterogeneity for optimal cell factories

    DEFF Research Database (Denmark)

    Heins, Anna-Lena; Carlqvist, Magnus; Helmark, S.;

    To achieve an efficient production process, it is essential to optimize both the strain and the cultivation conditions. Traditionally, a microbial population has been considered homogeneous in optimization studies of fermentation processes. However, research has shown that a typical microbial...

  1. Pixel Color Magnitude Diagrams for Semi-Resolved Stellar Populations: The Star Formation History of Regions within the Disk and Bulge of M31

    CERN Document Server

    Conroy, Charlie

    2016-01-01

    The analysis of stellar populations has, by and large, been developed for two limiting cases: spatially-resolved stellar populations in the color-magnitude diagram, and integrated light observations of distant systems. In between these two extremes lies the semi-resolved regime, which encompasses a rich and relatively unexplored realm of observational phenomena. Here we develop the concept of pixel color magnitude diagrams (pCMDs) as a powerful technique for analyzing stellar populations in the semi-resolved regime. pCMDs show the distribution of imaging data in the plane of pixel luminosity vs. pixel color. A key feature of pCMDs is that they are sensitive to all stars, including both the evolved giants and the unevolved main sequence stars. An important variable in this regime is the mean number of stars per pixel, $N_{\\rm pix}$. Simulated pCMDs demonstrate a strong sensitivity to the star formation history (SFH) and allow one to break degeneracies between age, metallicity and dust based on two filter data ...

  2. Progenitor cell populations in the periodontal ligament of mice

    International Nuclear Information System (INIS)

    Stem cells in a variety of renewal tissues exhibit a slow rate of cell proliferation. The periodontal ligament of mouse molars was examined for the presence of slowly cycling progenitor cells to provide evidence for the existence of stem cells in this tissue. A pulse injection of 3H-thymidine was administered and mice were sacrificed between 1 hour and 14 days after injection. Analysis of radioautographs using percentage of labeled cells and grain counts demonstrated that a population of label-retaining cells within 10 micron of blood vessels traversed the cell cycle more slowly than proliferating cells located greater than 10 micron from blood vessels. These data suggest that there is a slowly dividing population of progenitor cells in paravascular sites in mouse molar periodontal ligament which may be stem cells

  3. Single cell motility and trail formation in populations of microglia

    Science.gov (United States)

    Lee, Kyoung Jin

    2009-03-01

    Microglia are a special type of glia cell in brain that has immune responses. They constitute about 20 % of the total glia population within the brain. Compared to other glia cells, microglia are very motile, constantly moving to destroy pathogens and to remove dead neurons. While doing so, they exhibit interesting body shapes, have cell-to-cell communications, and have chemotatic responses to each other. Interestingly, our recent in vitro studies show that their unusual motile behaviors can self-organize to form trails, similar to those in populations of ants. We have studied the changes in the physical properties of these trails by varying the cell population density and by changing the degree of spatial inhomogeneities (``pathogens''). Our experimental observations can be quite faithfully reproduced by a simple mathematical model involving many motile cells whose mechanical motion are driven by actin polymerization and depolymerization process within the individual cell body and by external chemical gradients.

  4. Controlling the diversity of cell populations in a stem cell culture

    NARCIS (Netherlands)

    Heo, Inha; Clevers, Hans

    2015-01-01

    Culturing intestinal stem cells into 3D organoids results in heterogeneous cell populations, reflecting the in vivo cell type diversity. In a recent paper published in Nature, Wang et al. established a culture condition for a highly homogeneous population of intestinal stem cells.

  5. Time-resolved photoluminescence for evaluating laser-induced damage during dielectric stack ablation in silicon solar cells

    Science.gov (United States)

    Parola, Stéphanie; Blanc-Pélissier, Danièle; Barbos, Corina; Le Coz, Marine; Poulain, Gilles; Lemiti, Mustapha

    2016-06-01

    Selective laser ablation of dielectric layers on crystalline silicon wafers was investigated for solar cell fabrication. Laser processing was performed on Al2O3, and bi-layers Al2O3/SiNX:H with a nanosecond UV laser at various energy densities ranging from 0.4 to 2 J cm-2. Ablation threshold was correlated to the simulated temperature at the interface between the dielectric coatings and the silicon substrate. Laser-induced damage to the silicon substrate was evaluated by time-resolved photoluminescence. The minority carrier lifetime deduced from time-resolved photoluminescence was related to the depth of the heat affected zone in the substrate.

  6. Emergence of cytotoxic resistance in cancer cell populations: Single-cell mechanisms and population-level consequences

    Science.gov (United States)

    Lorenzi, Tommaso; Chisholm, Rebecca H.; Lorz, Alexander; Larsen, Annette K.; de Almeida, Luís Neves; Escargueil, Alexandre; Clairambault, Jean

    2016-06-01

    We formulate an individual-based model and a population model of phenotypic evolution, under cytotoxic drugs, in a cancer cell population structured by the expression levels of survival-potential and proliferation-potential. We apply these models to a recently studied experimental system. Our results suggest that mechanisms based on fundamental laws of biology can reversibly push an actively-proliferating, and drug-sensitive, cell population to transition into a weakly-proliferative and drug-tolerant state, which will eventually facilitate the emergence of more potent, proliferating and drug-tolerant cells.

  7. Fluctuations of cell population in a colonic crypt

    Science.gov (United States)

    Pei, Qi-ming; Zhan, Xuan; Yang, Li-jian; Bao, Chun; Cao, Wei; Li, An-bang; Rozi, Anvar; Jia, Ya

    2014-03-01

    The number of stem cells in a colonic crypt is often very small, which leads to large intrinsic fluctuations in the cell population. Based on the model of cell population dynamics with linear feedback in a colonic crypt, we present a stochastic dynamics of the cell population [including stem cells (SCs), transit amplifying cells (TACs), and fully differentiated cells (FDCs)]. The Fano factor, covariance, and susceptibility formulas of the cell population around the steady state are derived by using the Langevin theory. In the range of physiologically reasonable parameter values, it is found that the stationary populations of TACs and FDCs exhibit an approximately threshold behavior as a function of the net growth rate of TACs, and the reproductions of TACs and FDCs can be classified into three regimens: controlled, crossover, and uncontrolled. With the increasing of the net growth rate of TACs, there is a maximum of the relative intrinsic fluctuations (i.e., the Fano factors) of TACs and FDCs in the crossover region. For a fixed differentiation rate and the net growth rate of SCs, the covariance of fluctuations between SCs and TACs has a maximum in the crossover region. However, the susceptibilities of both TACs and FDCs to the net growth rate of TACs have a minimum in the crossover region.

  8. A focus on parietal cells as a renewing cell population

    Institute of Scientific and Technical Information of China (English)

    Sherif; M; Karam

    2010-01-01

    The fact that the acidsecreting parietal cells undergo continuous renewal has been ignored by many gastroenterologists and cell biologists. In the past, it was thought that these cells were static. However, by using 3Hthymidine radioautography in combination with electron microscopy, it was possible to demonstrate that parietal cells belong to a continuously renewing epithelial cell lineage. In the gastric glands, stem cells anchored in the isthmus region are responsible for the production of parietal cells...

  9. Cancer Stem Cells and Side Population Cells in Breast Cancer and Metastasis

    OpenAIRE

    Lennard, Thomas W.J.; Meeson, Annette P; Britton, Kelly M.; Kirby, John A.

    2011-01-01

    In breast cancer it is never the primary tumour that is fatal; instead it is the development of metastatic disease which is the major cause of cancer related mortality. There is accumulating evidence that suggests that Cancer Stem Cells (CSC) may play a role in breast cancer development and progression. Breast cancer stem cell populations, including side population cells (SP), have been shown to be primitive stem cell-like populations, being long-lived, self-renewing and highly proliferative....

  10. Human embryonic stem cell lines derived from the Chinese population

    Institute of Scientific and Technical Information of China (English)

    Zhen Fu FANG; Fan JIN; Hui GAI; Ying CHEN; Li WU; Ai Lian LIU; Bin CHEN; Hui Zhen SHENG

    2005-01-01

    Six human embryonic stem cell lines were established from surplus blastocysts. The cell lines expressed alkaline phosphatase and molecules typical of primate embryonic stem cells, including Oct-4, Nanog, TDGF1, Sox2, EBAF,Thy-1, FGF4, Rex-1, SSEA-3, SSEA-4, TRA-1-60 and TRA-1-81. Five of the six lines formed embryoid bodies that expressed markers of a variety of cell types; four of them formed teratomas with tissue types representative of all three embryonic germ layers. These human embryonic stem cells are capable of producing clones of undifferentiated morphology, and one of them was propagated to become a subline. Human embryonic stem cell lines from the Chinese population should facilitate stem cell research and may be valuable in studies of population genetics and ecology.

  11. An Investigation to Resolve the Interaction Between Fuel Cell, Power Conditioning System and Application Loads

    Energy Technology Data Exchange (ETDEWEB)

    Sudip K. Mazumder

    2005-12-31

    Development of high-performance and durable solidoxide fuel cells (SOFCs) and a SOFC power-generating system requires knowledge of the feedback effects from the power-conditioning electronics and from application-electrical-power circuits that may pass through or excite the power-electronics subsystem (PES). Therefore, it is important to develop analytical models and methodologies, which can be used to investigate and mitigate the effects of the electrical feedbacks from the PES and the application loads (ALs) on the reliability and performance of SOFC systems for stationary and non-stationary applications. However, any such attempt to resolve the electrical impacts of the PES on the SOFC would be incomplete unless one utilizes a comprehensive analysis, which takes into account the interactions of SOFC, PES, balance-of-plant system (BOPS), and ALs as a whole. SOFCs respond quickly to changes in load and exhibit high part- and full-load efficiencies due to its rapid electrochemistry, which is not true for the thermal and mechanical time constants of the BOPS, where load-following time constants are, typically, several orders of magnitude higher. This dichotomy can affect the lifetime and durability of the SOFCSs and limit the applicability of SOFC systems for load-varying stationary and transportation applications. Furthermore, without validated analytical models and investigative design and optimization methodologies, realizations of cost-effective, reliable, and optimal PESs (and power-management controls), in particular, and SOFC systems, in general, are difficult. On the whole, the research effort can lead to (a) cost-constrained optimal PES design for high-performance SOFCS and high energy efficiency and power density, (b) effective SOFC power-system design, analyses, and optimization, and (c) controllers and modulation schemes for mitigation of electrical impacts and wider-stability margin and enhanced system efficiency.

  12. Pixel Color Magnitude Diagrams for Semi-resolved Stellar Populations: The Star Formation History of Regions within the Disk and Bulge of M31

    Science.gov (United States)

    Conroy, Charlie; van Dokkum, Pieter G.

    2016-08-01

    The analysis of stellar populations has, by and large, been developed for two limiting cases: spatially resolved stellar populations in the color–magnitude diagram, and integrated light observations of distant systems. In between these two extremes lies the semi-resolved regime, which encompasses a rich and relatively unexplored realm of observational phenomena. Here we develop the concept of pixel color–magnitude diagrams (pCMDs) as a powerful technique for analyzing stellar populations in the semi-resolved regime. pCMDs show the distribution of imaging data in the plane of pixel luminosity versus pixel color. A key feature of pCMDs is that they are sensitive to all stars, including both the evolved giants and the unevolved main sequence stars. An important variable in this regime is the mean number of stars per pixel, {N}{{pix}}. Simulated pCMDs demonstrate a strong sensitivity to the star formation history (SFH) and have the potential to break degeneracies between age, metallicity and dust based on two filter data for values of {N}{{pix}} up to at least 104. We extract pCMDs from Hubble Space Telescope optical imaging of M31 and derive SFHs with seven independent age bins from 106 to 1010 year for both the crowded disk and bulge regions (where {N}{{pix}}≈ 30{--}{10}3). From analyzing a small region of the disk we find a SFH that is smooth and consistent with an exponential decay timescale of 4 Gyr. The bulge SFH is also smooth and consistent with a 2 Gyr decay timescale. pCMDs will likely play an important role in maximizing the science returns from next generation ground and space-based facilities.

  13. [Th9 cells: a new population of helper T cells].

    Science.gov (United States)

    Vegran, Frédérique; Martin, François; Apetoh, Lionel; Ghiringhelli, François

    2016-04-01

    Th9 cells are CD4 T helper cells characterized by their ability to produce IL-9 and IL-21. These cells are obtained from naive CD4(+) T cells cultured in the presence of TGF-β and IL-4. Thus their differentiation results from the balance between the signaling pathways induced by IL-4 in one hand and the one induced by TGF-β in the other hand. These cells are inflammatory cells and were first described in the context of atopic and autoimmune diseases in which they have a pathogenic role. They are also involved in the defense against parasite infections. Recently, some reports defined Th9 anticancer properties through their cytokine secretion. Indeed, their high secretion of IL-9 and IL-21 in the tumor bed contributes to their anticancer functions. These cytokines trigger the activation of dendritic cells, mast cells, natural killer cells, and CD8 T cells to mount an antitumor immune response. PMID:27137696

  14. Experimental depletion of different renal interstitial cell populations

    International Nuclear Information System (INIS)

    To define different populations of renal interstitial cells and investigate some aspects of their function, we studied the kidneys of normal rats and rats with hereditary diabetes insipidus (DI, Brattleboro) after experimental manipulations expected to alter the number of interstitial cells. DI rats showed an almost complete loss of interstitial cells in their renal papillae after treatment with a high dose of vasopressin. In spite of the lack of interstitial cells, the animals concentrated their urine to the same extent as vasopressin-treated normal rats, indicating that the renomedullary interstitial cells do not have an important function in concentrating the urine. The interstitial cells returned nearly to normal within 1 week off vasopressin treatment, suggesting a rapid turnover rate of these cells. To further distinguish different populations of interstitial cells, we studied the distribution of class II MHC antigen expression in the kidneys of normal and bone-marrow depleted Wistar rats. Normal rats had abundant class II antigen-positive interstitial cells in the renal cortex and outer medulla, but not in the inner medulla (papilla). Six days after 1000 rad whole body irradiation, the stainable cells were almost completely lost, but electron microscopic morphometry showed a virtually unchanged volume density of interstitial cells in the cortex and outer medulla, as well as the inner medulla. Thus, irradiation abolished the expression of the class II antigen but caused no significant depletion of interstitial cells

  15. Characterization of side population cells from human airway epithelium.

    Science.gov (United States)

    Hackett, Tillie-Louise; Shaheen, Furquan; Johnson, Andrew; Wadsworth, Samuel; Pechkovsky, Dmitri V; Jacoby, David B; Kicic, Anthony; Stick, Stephen M; Knight, Darryl A

    2008-10-01

    The airway epithelium is the first line of contact with the inhaled external environment and is continuously exposed to and injured by pollutants, allergens, and viruses. However, little is known about epithelial repair and in particular the identity and role of tissue resident stem/progenitor cells that may contribute to epithelial regeneration. The aims of the present study were to identify, isolate, and characterize side population (SP) cells in human tracheobronchial epithelium. Epithelial cells were obtained from seven nontransplantable healthy lungs and four asthmatic lungs by pronase digestion. SP cells were identified by verapamil-sensitive efflux of the DNA-binding dye Hoechst 33342. Using flow cytometry, CD45(-) SP, CD45(+) SP, and non-SP cells were isolated and sorted. CD45(-) SP cells made up 0.12% +/- 0.01% of the total epithelial cell population in normal airway but 4.1% +/- 0.06% of the epithelium in asthmatic airways. All CD45(-) SP cells showed positive staining for epithelial-specific markers cytokeratin-5, E-cadherin, ZO-1, and p63. CD45(-) SP cells exhibited stable telomere length and increased colony-forming and proliferative potential, undergoing population expansion for at least 16 consecutive passages. In contrast with non-SP cells, fewer than 100 CD45(-) SP cells were able to generate a multilayered and differentiated epithelium in air-liquid interface culture. SP cells are present in human tracheobronchial epithelium, exhibit both short- and long-term proliferative potential, and are capable of generation of differentiated epithelium in vitro. The number of SP cells is significantly greater in asthmatic airways, providing evidence of dysregulated resident SP cells in the asthmatic epithelium. Disclosure of potential conflicts of interest is found at the end of this article. PMID:18653771

  16. A focus on parietal cells as a renewing cell population

    Directory of Open Access Journals (Sweden)

    Sherif M Karam

    2010-02-01

    Full Text Available The fact that the acid-secreting parietal cells undergo continuous renewal has been ignored by many gastroenterologists and cell biologists. In the past, it was thought that these cells were static. However, by using 3H-thymidine radioautography in combination with electron microscopy, it was possible to demonstrate that parietal cells belong to a continuously renewing epithelial cell lineage. In the gastric glands, stem cells anchored in the isthmus region are responsible for the production of parietal cells. The stem cells give rise to three main progenitors: prepit, preneck and preparietal cells. Parietal cells develop either directly from the non-cycling preparietal cells or less commonly via differentiation of the cycling prepit and preneck cell progenitors. The formation of a parietal cell is a sequential process which involves diminishment of glycocalyx, production of cytoplasmic tubulovesicles, an increase in number and length of microvilli, an increase in number and size of mitochondria, and finally, expansion and invagination of the apical membrane with the formation of an intracellular canalicular system. Little is known about the genetic counterparts of these morphological events. However, the time dimension of parietal cell production and the consequences of its alteration on the biological features of the gastric gland are well documented. The production of a new parietal cell takes about 2 d. However, mature parietal cells have a long lifespan during which they migrate bi-directionally while their functional activity for acid secretion gradually diminishes. Following an average lifespan of about 54 d, in mice, old parietal cells undergo degeneration and elimination. Various approaches for genetic alteration of the development of parietal cells have provided evidence in support of their role as governors of the stem/progenitor cell proliferation and differentiation programs. Revealing the dynamic features and the various roles of

  17. A WFPC2 Study of the Resolved Stellar Population of the Pegasus Dwarf Irregular Galaxy (DDO 216)

    CERN Document Server

    Gallagher, J S; Dohm-Palmer, R C; Skillman, E D; Cole, A A; Hössel, J G; Saha, A; Mateo, M; Tolstoy, Eline; Dohm-Palmer, Robbie C.

    1998-01-01

    The stellar population of the Pegasus dwarf irregular galaxy is investigated in images taken in the F439W (B), F555W (V), and F814W (I) bands with WFPC2. These and ground-based data are combined to produce color-magnitude diagrams which show the complex nature of the stellar population in this small galaxy. A young (< 0.5 Gyr) main sequence stellar component is present and clustered in two centrally-located clumps, while older stars form a more extended disk or halo. The colors of the main sequence require a relatively large extinction of A_V = 0.47 mag. The mean color of the well-populated red giant branch is relatively blue, consistent with a moderate metallicity young, or older, metal-poor stellar population. The red giant branch also has significant width in color, implying a range of stellar ages and/or metallicities. A small number of extended asymptotic giant branch stars are found beyond the red giant branch tip. Near the faint limits of our data is a populous red clump superimposed on the red gian...

  18. 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.

  19. AN INVESTIGATION TO RESOLVE THE INTERACTION BETWEEN FUEL CELL, POWER CONDITIONING SYSTEM AND APPLICATION LOADS

    Energy Technology Data Exchange (ETDEWEB)

    Sudip K. Mazumder; Chuck McKintyre; Dan Herbison; Doug Nelson; Comas Haynes; Michael von Spakovsky; Joseph Hartvigsen; S. Elangovan

    2003-11-03

    Solid-Oxide Fuel Cell (SOFC) stacks respond quickly to changes in load and exhibit high part- and full-load efficiencies due to its rapid electrochemistry. However, this is not true for the thermal, mechanical, and chemical balance-of-plant subsystem (BOPS), where load-following time constants are, typically, several orders of magnitude higher. This dichotomy diminishes the reliability and performance of the electrode with increasing demand of load. Because these unwanted phenomena are not well understood, the manufacturers of SOFC use conservative schemes (such as, delayed load-following to compensate for slow BOPS response or expensive inductor filtering) to control stack responses to load variations. This limits the applicability of SOFC systems for load-varying stationary and transportation applications from a cost standpoint. Thus, a need exists for the synthesis of component- and system-level models of SOFC power-conditioning systems and the development of methodologies for investigating the system-interaction issues (which reduce the lifetime and efficiency of a SOFC) and optimizing the responses of each subsystem, leading to optimal designs of power-conditioning electronics and optimal control strategies, which mitigate the electrical-feedback effects. Equally important are ''multiresolution'' finite-element modeling and simulation studies, which can predict the impact of changes in system-level variables (e.g., current ripple and load-transients) on the local current densities, voltages, and temperature (these parameters are very difficult or cumbersome, if not impossible to obtain) within a SOFC cell. Towards that end, for phase I of this project, sponsored by the U.S. DOE (NETL), we investigate the interactions among fuel cell, power-conditioning system, and application loads and their effects on SOFC reliability (durability) and performance. A number of methodologies have been used in Phase I to develop the steady-state and transient

  20. Trail networks formed by populations of immune cells

    Science.gov (United States)

    Yang, Taeseok Daniel; Kwon, Tae Goo; Park, Jin-sung; Lee, Kyoung J.

    2014-02-01

    Populations of biological cells that communicate with each other can organize themselves to generate large-scale patterns. Examples can be found in diverse systems, ranging from developing embryos, cardiac tissues, chemotaxing ameba and swirling bacteria. The similarity, often shared by the patterns, suggests the existence of some general governing principle. On the other hand, rich diversity and system-specific properties are exhibited, depending on the type of involved cells and the nature of their interactions. The study on the similarity and the diversity constitutes a rapidly growing field of research. Here, we introduce a new class of self-organized patterns of cell populations that we term as ‘cellular trail networks’. They were observed with populations of rat microglia, the immune cells of the brain and the experimental evidence suggested that haptotaxis is the key element responsible for them. The essential features of the observed patterns are well captured by the mathematical model cells that actively crawl and interact with each other through a decomposing but non-diffusing chemical attractant laid down by the cells. Our finding suggests an unusual mechanism of socially cooperative long-range signaling for the crawling immune cells.

  1. Synergistic interaction between selective drugs in cell populations models.

    Directory of Open Access Journals (Sweden)

    Victoria Doldán-Martelli

    Full Text Available The design of selective drugs and combinatorial drug treatments are two of the main focuses in modern pharmacology. In this study we use a mathematical model of chimeric ligand-receptor interaction to show that the combination of selective drugs is synergistic in nature, providing a way to gain optimal selective potential at reduced doses compared to the same drugs when applied individually. We use a cell population model of proliferating cells expressing two different amounts of a target protein to show that both selectivity and synergism are robust against variability and heritability in the cell population. The reduction in the total drug administered due to the synergistic performance of the selective drugs can potentially result in reduced toxicity and off-target interactions, providing a mechanism to improve the treatment of cell-based diseases caused by aberrant gene overexpression, such as cancer and diabetes.

  2. Characterization of Side Population Cells from Human Airway Epithelium

    OpenAIRE

    Hackett, Tillie-Louise; Shaheen, Furquan; Johnson, Andrew; Wadsworth, Samuel; Pechkovsky, Dmitri V; Jacoby, David B.; Kicic, Anthony; Stick, Stephen M.; Knight, Darryl A.

    2008-01-01

    The airway epithelium is the first line of contact with the inhaled external environment and is continuously exposed to and injured by pollutants, allergens, and viruses. However, little is known about epithelial repair and in particular the identity and role of tissue resident stem/progenitor cells that may contribute to epithelial regeneration. The aims of the present study were to identify, isolate, and characterize side population (SP) cells in human tracheobronchial epithelium. Epithelia...

  3. Optimal Population Codes for Space: Grid Cells Outperform Place Cells

    OpenAIRE

    Mathis, Alexander; Herz, Andreas V. M.; Stemmler, Martin B

    2012-01-01

    Rodents use two distinct neuronal coordinate systems to estimate their position: place fields in the hippocampus and grid fields in the entorhinal cortex. Whereas place cells spike at only one particular spatial lo- cation, grid cells fire at multiple sites that correspond to the points of an imaginary hexagonal lattice. We study how to best construct place and grid codes, taking the probabilistic nature of neural spiking into account. Which spatial encoding properties of individu...

  4. 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

  5. Resolved H I imaging of a population of massive H I-rich galaxies with suppressed star formation

    International Nuclear Information System (INIS)

    Despite the existence of well-defined relationships between cold gas and star formation, there is evidence that some galaxies contain large amounts of H I that do not form stars efficiently. By systematically assessing the link between H I and star formation within a sample of galaxies with extremely high H I masses (log MHI/M☉ > 10), we uncover a population of galaxies with an unexpected combination of high H I masses and low specific star formation rates that exists primarily at stellar masses greater than log M*/M☉ ∼ 10.5. We obtained H I maps of 20 galaxies in this population to understand the distribution of the H I and the physical conditions in the galaxies that could be suppressing star formation in the presence of large quantities of H I. We find that all of the galaxies we observed have low H I surface densities in the range in which inefficient star formation is common. The low H I surface densities are likely the main cause of the low specific star formation rates, but there is also some evidence that active galactic nuclei or bulges contribute to the suppression of star formation. The sample's agreement with the global star formation law highlights its usefulness as a tool for understanding galaxies that do not always follow expected relationships.

  6. Resolved H I imaging of a population of massive H I-rich galaxies with suppressed star formation

    Energy Technology Data Exchange (ETDEWEB)

    Lemonias, Jenna J.; Schiminovich, David [Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States); Catinella, Barbara [Swinburne University of Technology, Centre for Astrophysics and Supercomputing, P.O. Box 218, Mail H30, Hawthorn, VIC 3122 (Australia); Heckman, Timothy M. [Department of Physics and Astronomy, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Moran, Sean M., E-mail: jenna@astro.columbia.edu [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States)

    2014-07-20

    Despite the existence of well-defined relationships between cold gas and star formation, there is evidence that some galaxies contain large amounts of H I that do not form stars efficiently. By systematically assessing the link between H I and star formation within a sample of galaxies with extremely high H I masses (log M{sub H{sub I}}/M{sub ☉} > 10), we uncover a population of galaxies with an unexpected combination of high H I masses and low specific star formation rates that exists primarily at stellar masses greater than log M{sub *}/M{sub ☉} ∼ 10.5. We obtained H I maps of 20 galaxies in this population to understand the distribution of the H I and the physical conditions in the galaxies that could be suppressing star formation in the presence of large quantities of H I. We find that all of the galaxies we observed have low H I surface densities in the range in which inefficient star formation is common. The low H I surface densities are likely the main cause of the low specific star formation rates, but there is also some evidence that active galactic nuclei or bulges contribute to the suppression of star formation. The sample's agreement with the global star formation law highlights its usefulness as a tool for understanding galaxies that do not always follow expected relationships.

  7. Isolation of basal and mucous cell populations from rabbit trachea

    International Nuclear Information System (INIS)

    The application of a unit gravity sedimentation procedure to monodispersed rabbit tracheal cells resulted in the isolation of enriched (2-fold to 2.5-fold) basal and mucous cell populations. Cellular integrity was confirmed by a trypan blue dye exclusion index of 93%, [3H] leucine incorporation, and ultrastructural analysis. Unit gravity sedimentation is an affective and rapid procedure for obtaining viable, homogeneous preparations of basal and mucous cells that may be used for in vitro studies of cellular proliferation, differentiation, and glycoprotein biosynthesis in respiratory mucous epithelia

  8. Time-resolved measurements of the hot-electron population in ignition-scale experiments on the National Ignition Facility (invited).

    Science.gov (United States)

    Hohenberger, M; Albert, F; Palmer, N E; Lee, J J; Döppner, T; Divol, L; Dewald, E L; Bachmann, B; MacPhee, A G; LaCaille, G; Bradley, D K; Stoeckl, C

    2014-11-01

    In laser-driven inertial confinement fusion, hot electrons can preheat the fuel and prevent fusion-pellet compression to ignition conditions. Measuring the hot-electron population is key to designing an optimized ignition platform. The hot electrons in these high-intensity, laser-driven experiments, created via laser-plasma interactions, can be inferred from the bremsstrahlung generated by hot electrons interacting with the target. At the National Ignition Facility (NIF) [G. H. Miller, E. I. Moses, and C. R. Wuest, Opt. Eng. 43, 2841 (2004)], the filter-fluorescer x-ray (FFLEX) diagnostic-a multichannel, hard x-ray spectrometer operating in the 20-500 keV range-has been upgraded to provide fully time-resolved, absolute measurements of the bremsstrahlung spectrum with ∼300 ps resolution. Initial time-resolved data exhibited significant background and low signal-to-noise ratio, leading to a redesign of the FFLEX housing and enhanced shielding around the detector. The FFLEX x-ray sensitivity was characterized with an absolutely calibrated, energy-dispersive high-purity germanium detector using the high-energy x-ray source at NSTec Livermore Operations over a range of K-shell fluorescence energies up to 111 keV (U Kβ). The detectors impulse response function was measured in situ on NIF short-pulse (∼90 ps) experiments, and in off-line tests. PMID:25430175

  9. Time-resolved measurements of the hot-electron population in ignition-scale experiments on the National Ignition Facility (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Hohenberger, M., E-mail: mhoh@lle.rochester.edu; Stoeckl, C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Albert, F.; Palmer, N. E.; Döppner, T.; Divol, L.; Dewald, E. L.; Bachmann, B.; MacPhee, A. G.; LaCaille, G.; Bradley, D. K. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Lee, J. J. [National Security Technologies LLC, Livermore, California 94551 (United States)

    2014-11-15

    In laser-driven inertial confinement fusion, hot electrons can preheat the fuel and prevent fusion-pellet compression to ignition conditions. Measuring the hot-electron population is key to designing an optimized ignition platform. The hot electrons in these high-intensity, laser-driven experiments, created via laser-plasma interactions, can be inferred from the bremsstrahlung generated by hot electrons interacting with the target. At the National Ignition Facility (NIF) [G. H. Miller, E. I. Moses, and C. R. Wuest, Opt. Eng. 43, 2841 (2004)], the filter-fluorescer x-ray (FFLEX) diagnostic–a multichannel, hard x-ray spectrometer operating in the 20–500 keV range–has been upgraded to provide fully time-resolved, absolute measurements of the bremsstrahlung spectrum with ∼300 ps resolution. Initial time-resolved data exhibited significant background and low signal-to-noise ratio, leading to a redesign of the FFLEX housing and enhanced shielding around the detector. The FFLEX x-ray sensitivity was characterized with an absolutely calibrated, energy-dispersive high-purity germanium detector using the high-energy x-ray source at NSTec Livermore Operations over a range of K-shell fluorescence energies up to 111 keV (U K{sub β}). The detectors impulse response function was measured in situ on NIF short-pulse (∼90 ps) experiments, and in off-line tests.

  10. 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

  11. Nanophotothermolysis of multiple scattered cancer cells with carbon nanotubes guided by time-resolved infrared thermal imaging.

    Science.gov (United States)

    Biris, Alexandru S; Boldor, Dorin; Palmer, Jason; Monroe, William T; Mahmood, Meena; Dervishi, Enkeleda; Xu, Yang; Li, Zhongrui; Galanzha, Ekaterina I; Zharov, Vladimir P

    2009-01-01

    Nanophotothermolysis with long laser pulses for treatment of scattered cancer cells and their clusters is introduced with the main focus on real-time monitoring of temperature dynamics inside and around individual cancer cells labeled with carbon nanotubes. This technique utilizes advanced time- and spatially-resolved thermal radiometry imaging for the visualization of laser-induced temperature distribution in multiple-point absorbing targets. The capability of this approach was demonstrated for monitoring of thermal effects under long laser exposure (from millisecond to seconds, wavelength 1,064 nm, maximum power 1 W) of cervical cancer HeLa cells labeled with carbon nanotubes in vitro. The applications are discussed with a focus on the nanophotothermolysis of small tumors, tumor margins, or micrometastases under the guidance of near-IR and microwave radiometry. PMID:19405720

  12. Transient Response of Organo-Metal-Halide Solar Cells Analyzed by Time-Resolved Current-Voltage Measurements

    Directory of Open Access Journals (Sweden)

    M. Greyson Christoforo

    2015-11-01

    Full Text Available The determination of the power conversion efficiency of solar cells based on organo-metal-halides is subject to an ongoing debate. As solar cell devices may exhibit very slow transient response, current-voltage scans in different directions may not be congruent, which is an effect often referred to as hysteresis. We here discuss time-resolved current-voltage measurements as a means to evaluate appropriate delay times (voltage settling times to be used in current-voltage measurements of solar cells. Furthermore, this method allows the analysis of transient current response to extract time constants that can be used to compare characteristic differences between devices of varying architecture types, selective contacts and changes in devices due to storage or degradation conditions.

  13. Essential Function of Dicer in Resolving DNA Damage in the Rapidly Dividing Cells of the Developing and Malignant Cerebellum

    Directory of Open Access Journals (Sweden)

    Vijay Swahari

    2016-01-01

    Full Text Available Maintenance of genomic integrity is critical during neurodevelopment, particularly in rapidly dividing cerebellar granule neuronal precursors that experience constitutive replication-associated DNA damage. As Dicer was recently recognized to have an unexpected function in the DNA damage response, we examined whether Dicer was important for preserving genomic integrity in the developing brain. We report that deletion of Dicer in the developing mouse cerebellum resulted in the accumulation of DNA damage leading to cerebellar progenitor degeneration, which was rescued with p53 deficiency; deletion of DGCR8 also resulted in similar DNA damage and cerebellar degeneration. Dicer deficiency also resulted in DNA damage and death in other rapidly dividing cells including embryonic stem cells and the malignant cerebellar progenitors in a mouse model of medulloblastoma. Together, these results identify an essential function of Dicer in resolving the spontaneous DNA damage that occurs during the rapid proliferation of developmental progenitors and malignant cells.

  14. Electrical characterization of Cu(In,Ga)Se2-solar cells by voltage dependent time-resolved photoluminescence

    International Nuclear Information System (INIS)

    Time-resolved photoluminescence (TRPL) is a promising method for the investigation of charge carrier dynamics and recombination kinetics in semiconductor devices. To characterize Cu(In,Ga)Se2 (CIGSe) solar cells, we measured TRPL for different applied external forward voltages. We show that the TRPL decay time increases with increasing voltage in case of a high excitation intensity. This result is valid for a wide range of excitation frequencies of the laser. By simulation of the measured transients we determined semiconductor parameters which allow fitting the experimental photoluminescence transients for different voltages. The deduced quantities are the lifetime for deep defect assisted Schockley-Read-Hall recombination, doping density and charge carrier mobilities of the solar cell's absorber layer with values of 10 ns, 2 × 1015 cm−3 and 1 cm2 V−1 s−1, respectively, for a standard CIGSe solar cell. We further studied the appearance of a photovoltage in TRPL experiments with single-photon-counting methods. By experimental results we show a dependence of the open circuit voltage on the laser repetition rate, which influences the TRPL decay. - Highlights: • Time-resolved photoluminescence on Cu(In,Ga)Se2-solar for different bias voltages • Build up of a photovoltage that varies luminescence decay for open circuit conditions • Inhibition of luminescence decay for increasing bias forward voltages • Determination of charge carrier mobilities and minority carrier lifetime by simulations

  15. Senescent cells in growing tumors: population dynamics and cancer stem cells

    OpenAIRE

    C.A.M. La Porta; Zapperi, S.; Sethna, J. P.

    2012-01-01

    Author Summary It is commonly believed that cell senescence – the loss of replicative capacity of cells – acts as a barrier for tumor growth. Here we follow the evolution of senescence markers in melanoma cells and find that while most cancer cells eventually turn senescent, this is at root irrelevant for the long-term growth rate of a tumor. To demonstrate this, we construct a mathematical population dynamics model incorporating cancer stem cells which is able to reproduce quantitatively the...

  16. Phylogenetic performance of mitochondrial protein-coding genes of Oncomelania hupensis in resolving relationships between landscape populations

    Institute of Scientific and Technical Information of China (English)

    Shi-Zhu LI; Li ZHANG; Lin MA; Wei HU; Shan LV; Qin LIU; Ying-Jun QIAN

    2013-01-01

    Oncomelania hupensis is the unique intermediate host of Schistosomajaponicum,which plays a key role in the transmission of human blood fluke Schistosoma.The complete mitochondrial (mt) genome of O.hupensis has been characterized; however,the phylogenetic performance of mt protein-coding genes (PCGs) of the snail remain unclear.In this study,11 whole mt genomes of snails collected from four different ecological settings in China and the Philippines were sequenced.The mt genome sizes ranged from 15 183 to 15 216 bp,with the G + C contents from 32.4% to 33.4%.A total of 15 251 characters were generated from the multiple sequence alignment.Of 2711 (17.8%)polymorphic sites,56.22% (1524) were parsimony sites.The mt genomes' phylogenetic trees were reconstructed using minimum evolution,neighbor joining,maximum likelihood,maximum parsimony,and Bayesian tree estimate methods,and two main distinct clades were identified:(i) the isolate from mountainous regions; (ii) the remaining isolate which included three inner branches.All phylogenetic trees of the 13 PCGs were generated by running 1000 bootstrap replicates and compared with the complete mtDNA tree,the classification accuracy ranging from 21.23% to 87.87%,the topological distance of phylogenetic trees between PCGs ranging from 5 to 14.Therefore,the performance of PCGs can be divided into good condition (COⅠ,ND2,ND5,and ND3),medium (COⅡ,ATP6,ND1,ND6,Cytb,ND4,and COⅢ),poor (ATP8 and ND4L).This study represents the first analysis ofmt genome diversity of the O.hupensis snail and phylogenetic performance of mt PCGs.It presents clear evidence that the snail populations can be separated into four landscape genetic populations in mainland China based on whole mt genomes.The identification of the phylogenetic performance of PCGs provides new insight into the intensive genetic diversity study using mtDNA markers for the snail.

  17. Spatially Resolved Stellar Populations Of Nearby Post-Starburst Galaxies In SDSS-IV MaNGA

    Science.gov (United States)

    Liu, Charles; Betances, Ashley; Bonilla, Alaina Marie; Gonzalez, Andrea; Migliore, Christina; Goddard, Daniel; Masters, Karen; SDSS-IV MaNGA Team

    2016-01-01

    We have selected five galaxies in the Mapping Nearby Galaxies at APO (MaNGA) project of the latest generation of the Sloan Digital Sky Survey (SDSS-IV) identified as post-starburst (E+A) systems, in the transition between "blue cloud" and "red sequence" galaxies. We measure the equivalent widths of the Balmer series, D4000 break, and metal lines across each galaxy, and produce maps of the stellar age, stellar mass, and metallicities of each galaxy using FIREFLY, a full spectral analysis code. We have found that the measured properties of the galaxies overall generally matches well with single-aperture SDSS spectra from which the original post-starburst identifications were made. The variation in the spatial distributions of the stellar populations, in particular the A-stars, give us insight into the details of the transitional E+A quenching phase. This work was supported by the Alfred P. Sloan Foundation via the SDSS-IV Faculty and Student Team (FAST) initiative, ARC Agreement No. SSP483 to the CUNY College of Staten Island.

  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. Correlation of spatially resolved lifetime measurements with overall solar cell parameters

    Energy Technology Data Exchange (ETDEWEB)

    Isenberg, J.; Dicker, J.; Riepe, S.; Ballif, C.; Peters, S.; Lautenschlager, H.; Schindler, R.; Warta, W. [Fraunhofer-Institut fuer Solare Energiesysteme (ISE), Freiburg im Breisgau (Germany)

    2002-07-01

    Lifetime mappings are common tools for assessing the quality of mc-silicon for solar cell production. Nevertheless it is a difficult problem to directly relate lifetime mappings to overall solar cell parameters. This paper intends to show that this correlation is possible quantitatively. We have correlated actual low-level injection lifetimes obtained by carrier density imaging (CDI) measurements with overall cell parameters of solar cells processed on adjacent wafers. The 2D lifetime-structure is taken account for by appropriate weighing functions that include the whole information given in the frequency distribution of bulk lifetimes. Thus a one dimensional cell model (PC1D) can be applied. Good general agreement between predicted and measured cell parameters has been achieved, deviations are discussed. Further insight into the gettering behavior of block-cast and Bridgman-grown mc-silicon was attained. (orig.)

  20. Cancer Stem Cells and Side Population Cells in Breast Cancer and Metastasis

    Energy Technology Data Exchange (ETDEWEB)

    Britton, Kelly M. [Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle-upon-Tyne, NE1 3BZ (United Kingdom); Kirby, John A. [Institute of Cellular Medicine, Newcastle University, 3rd Floor William Leech Building, Framlington Place, Newcastle-upon-Tyne, NE2 4HH (United Kingdom); Lennard, Thomas W.J. [Faculty of Medical Sciences, Newcastle University, 3rd Floor William Leech Building, Framlington Place, Newcastle-upon-Tyne, NE2 4HH (United Kingdom); Meeson, Annette P., E-mail: annette.meeson@ncl.ac.uk [Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle-upon-Tyne, NE1 3BZ (United Kingdom); North East England Stem Cell Institute, Bioscience Centre, International Centre for Life, Central Parkway, Newcastle-upon-Tyne, NE1 3BZ (United Kingdom)

    2011-04-19

    In breast cancer it is never the primary tumour that is fatal; instead it is the development of metastatic disease which is the major cause of cancer related mortality. There is accumulating evidence that suggests that Cancer Stem Cells (CSC) may play a role in breast cancer development and progression. Breast cancer stem cell populations, including side population cells (SP), have been shown to be primitive stem cell-like populations, being long-lived, self-renewing and highly proliferative. SP cells are identified using dual wavelength flow cytometry combined with Hoechst 33342 dye efflux, this ability is due to expression of one or more members of the ABC transporter family. They have increased resistance to chemotherapeutic agents and apoptotic stimuli and have increased migratory potential above that of the bulk tumour cells making them strong candidates for the metastatic spread of breast cancer. Treatment of nearly all cancers usually involves one first-line agent known to be a substrate of an ABC transporter thereby increasing the risk of developing drug resistant tumours. At present there is no marker available to identify SP cells using immunohistochemistry on breast cancer patient samples. If SP cells do play a role in breast cancer progression/Metastatic Breast Cancer (MBC), combining chemotherapy with ABC inhibitors may be able to destroy both the cells making up the bulk tumour and the cancer stem cell population thus preventing the risk of drug resistant disease, recurrence or metastasis.

  1. Cancer Stem Cells and Side Population Cells in Breast Cancer and Metastasis

    International Nuclear Information System (INIS)

    In breast cancer it is never the primary tumour that is fatal; instead it is the development of metastatic disease which is the major cause of cancer related mortality. There is accumulating evidence that suggests that Cancer Stem Cells (CSC) may play a role in breast cancer development and progression. Breast cancer stem cell populations, including side population cells (SP), have been shown to be primitive stem cell-like populations, being long-lived, self-renewing and highly proliferative. SP cells are identified using dual wavelength flow cytometry combined with Hoechst 33342 dye efflux, this ability is due to expression of one or more members of the ABC transporter family. They have increased resistance to chemotherapeutic agents and apoptotic stimuli and have increased migratory potential above that of the bulk tumour cells making them strong candidates for the metastatic spread of breast cancer. Treatment of nearly all cancers usually involves one first-line agent known to be a substrate of an ABC transporter thereby increasing the risk of developing drug resistant tumours. At present there is no marker available to identify SP cells using immunohistochemistry on breast cancer patient samples. If SP cells do play a role in breast cancer progression/Metastatic Breast Cancer (MBC), combining chemotherapy with ABC inhibitors may be able to destroy both the cells making up the bulk tumour and the cancer stem cell population thus preventing the risk of drug resistant disease, recurrence or metastasis

  2. A computational approach to resolve cell level contributions to early glandular epithelial cancer progression

    Directory of Open Access Journals (Sweden)

    Park Sunwoo

    2009-12-01

    Full Text Available Abstract Background Three-dimensional (3D embedded cell cultures provide an appropriate physiological environment to reconstruct features of early glandular epithelial cancer. Although these are orders of magnitude simpler than tissues, they too are complex systems that have proven challenging to understand. We used agent-based, discrete event simulation modeling methods to build working hypotheses of mechanisms of epithelial 3D culture phenotype and early cancer progression. Starting with an earlier software analogue, we validated an improved in silico epithelial analogue (ISEA for cardinal features of a normally developed MDCK cyst. A set of axiomatic operating principles defined simulated cell actions. We explored selective disruption of individual simulated cell actions. New framework features enabled recording detailed measures of ISEA cell activities and morphology. Results Enabled by a small set of cell operating principles, ISEA cells multiplied and self-organized into cyst-like structures that mimicked those of MDCK cells in a 3D embedded cell culture. Selective disruption of "anoikis" or directional cell division caused the ISEA to develop phenotypic features resembling those of in vitro tumor reconstruction models and cancerous tissues in vivo. Disrupting either process, or both, altered cell activity patterns that resulted in morphologically similar outcomes. Increased disruption led to a prolonged presence of intraluminal cells. Conclusions ISEA mechanisms, behaviors, and morphological properties may have biological counterparts. To the extent that in silico-to-in vitro mappings are valid, the results suggest plausible, additional mechanisms of in vitro cancer reconstruction or reversion, and raise potentially significant implications for early cancer diagnosis based on histology. Further ISEA development and use are expected to provide a viable platform to complement in vitro methods for unraveling the mechanistic basis of

  3. Cell-specific information processing in segregating populations of Eph receptor ephrin-expressing cells

    DEFF Research Database (Denmark)

    Jørgensen, Claus; Sherman, Andrew; Chen, Ginny I; Pasculescu, Adrian; Poliakov, Alexei; Hsiung, Marilyn; Larsen, Brett; Wilkinson, David G; Linding, Rune; Pawson, Tony

    2009-01-01

    Cells have self-organizing properties that control their behavior in complex tissues. Contact between cells expressing either B-type Eph receptors or their transmembrane ephrin ligands initiates bidirectional signals that regulate cell positioning. However, simultaneously investigating how...... information is processed in two interacting cell types remains a challenge. We implemented a proteomic strategy to systematically determine cell-specific signaling networks underlying EphB2- and ephrin-B1-controlled cell sorting. Quantitative mass spectrometric analysis of mixed populations of EphB2- and...... revealed that signaling between mixed EphB2- and ephrin-B1-expressing cells is asymmetric and that the distinct cell types use different tyrosine kinases and targets to process signals induced by cell-cell contact. We provide systems- and cell-specific network models of contact-initiated signaling between...

  4. Live cell imaging of SOS and prophage dynamics in isogenic bacterial populations.

    Science.gov (United States)

    Helfrich, Stefan; Pfeifer, Eugen; Krämer, Christina; Sachs, Christian Carsten; Wiechert, Wolfgang; Kohlheyer, Dietrich; Nöh, Katharina; Frunzke, Julia

    2015-11-01

    Almost all bacterial genomes contain DNA of viral origin, including functional prophages or degenerated phage elements. A frequent but often unnoted phenomenon is the spontaneous induction of prophage elements (SPI) even in the absence of an external stimulus. In this study, we have analyzed SPI of the large, degenerated prophage CGP3 (187 kbp), which is integrated into the genome of the Gram-positive Corynebacterium glutamicum ATCC 13032. Time-lapse fluorescence microscopy of fluorescent reporter strains grown in microfluidic chips revealed the sporadic induction of the SOS response as a prominent trigger of CGP3 SPI but also displayed a considerable fraction (∼30%) of RecA-independent SPI. Whereas approx. 20% of SOS-induced cells recovered from this stress and resumed growth, the spontaneous induction of CGP3 always led to a stop of growth and likely cell death. A carbon source starvation experiment clearly emphasized that SPI only occurs in actively proliferating cells, whereas sporadic SOS induction was still observed in resting cells. These data highlight the impact of sporadic DNA damage on the activity of prophage elements and provide a time-resolved, quantitative description of SPI as general phenomenon of bacterial populations. PMID:26235130

  5. Characterization of Side Cell Populations Obtained from Human Amnion Mesenchymal Cells

    Institute of Scientific and Technical Information of China (English)

    LI Ning; PIAO Zhengfu; Mamoru Kobayashi; Koji Sasaki; DING Shu-qin; Aiko Kikuchi; Isao Kamo; Norio Sakuragawa

    2009-01-01

    Human amnion mesenchymal cells (AMCs) contain multipotent cells. To enrich such multipotent stem cells, we applied to AMCs the new method for the isolation of side population (SP) cells used for the enrichment of multipotent stem cells from many tissues. We succeeded in obtaining SP cells from AMCs (AMC-SP cells). AMC-SP cells were found in 0.2% of AMCs, irrespective of the length of pregnant period, ranging from 37 to 40 weeks. Cell cycle analyses uggested that AMC-SP cells belonged to a cell population that proliferated very slowly and/or was in a quiescent state in the amniotic membrane. Upon culturing, they proliferated with 40 to 80 cell doublings. However, they did not form colonies in a soft agarose culture, whereas HepG2 cells, representative human hepatoma cells formed many large colonies. These results suggest that AMC-SP cells that have considerable value for the use of regenerative medicine can be managed safely in vitro.

  6. Population genetics inside a cell: Mutations and mitochondrial genome maintenance

    Science.gov (United States)

    Goyal, Sidhartha; Shraiman, Boris; Gottschling, Dan

    2012-02-01

    In realistic ecological and evolutionary systems natural selection acts on multiple levels, i.e. it acts on individuals as well as on collection of individuals. An understanding of evolutionary dynamics of such systems is limited in large part due to the lack of experimental systems that can challenge theoretical models. Mitochondrial genomes (mtDNA) are subjected to selection acting on cellular as well as organelle levels. It is well accepted that mtDNA in yeast Saccharomyces cerevisiae is unstable and can degrade over time scales comparable to yeast cell division time. We utilize a recent technology designed in Gottschling lab to extract DNA from populations of aged yeast cells and deep sequencing to characterize mtDNA variation in a population of young and old cells. In tandem, we developed a stochastic model that includes the essential features of mitochondrial biology that provides a null model for expected mtDNA variation. Overall, we find approximately 2% of the polymorphic loci that show significant increase in frequency as cells age providing direct evidence for organelle level selection. Such quantitative study of mtDNA dynamics is absolutely essential to understand the propagation of mtDNA mutations linked to a spectrum of age-related diseases in humans.

  7. Time-resolved, single-cell analysis of induced and programmed cell death via non-invasive propidium iodide and counterstain perfusion.

    Science.gov (United States)

    Krämer, Christina E M; Wiechert, Wolfgang; Kohlheyer, Dietrich

    2016-01-01

    Conventional propidium iodide (PI) staining requires the execution of multiple steps prior to analysis, potentially affecting assay results as well as cell vitality. In this study, this multistep analysis method has been transformed into a single-step, non-toxic, real-time method via live-cell imaging during perfusion with 0.1 μM PI inside a microfluidic cultivation device. Dynamic PI staining was an effective live/dead analytical tool and demonstrated consistent results for single-cell death initiated by direct or indirect triggers. Application of this method for the first time revealed the apparent antibiotic tolerance of wild-type Corynebacterium glutamicum cells, as indicated by the conversion of violet fluorogenic calcein acetoxymethyl ester (CvAM). Additional implementation of this method provided insight into the induced cell lysis of Escherichia coli cells expressing a lytic toxin-antitoxin module, providing evidence for non-lytic cell death and cell resistance to toxin production. Finally, our dynamic PI staining method distinguished necrotic-like and apoptotic-like cell death phenotypes in Saccharomyces cerevisiae among predisposed descendants of nutrient-deprived ancestor cells using PO-PRO-1 or green fluorogenic calcein acetoxymethyl ester (CgAM) as counterstains. The combination of single-cell cultivation, fluorescent time-lapse imaging, and PI perfusion facilitates spatiotemporally resolved observations that deliver new insights into the dynamics of cellular behaviour. PMID:27580964

  8. A pure population of lung alveolar epithelial type II cells derived from human embryonic stem cells.

    Science.gov (United States)

    Wang, Dachun; Haviland, David L; Burns, Alan R; Zsigmond, Eva; Wetsel, Rick A

    2007-03-13

    Alveolar epithelial type II (ATII) cells are small, cuboidal cells that constitute approximately 60% of the pulmonary alveolar epithelium. These cells are crucial for repair of the injured alveolus by differentiating into alveolar epithelial type I cells. ATII cells derived from human ES (hES) cells are a promising source of cells that could be used therapeutically to treat distal lung diseases. We have developed a reliable transfection and culture procedure, which facilitates, via genetic selection, the differentiation of hES cells into an essentially pure (>99%) population of ATII cells (hES-ATII). Purity, as well as biological features and morphological characteristics of normal ATII cells, was demonstrated for the hES-ATII cells, including lamellar body formation, expression of surfactant proteins A, B, and C, alpha-1-antitrypsin, and the cystic fibrosis transmembrane conductance receptor, as well as the synthesis and secretion of complement proteins C3 and C5. Collectively, these data document the successful generation of a pure population of ATII cells derived from hES cells, providing a practical source of ATII cells to explore in disease models their potential in the regeneration and repair of the injured alveolus and in the therapeutic treatment of genetic diseases affecting the lung. PMID:17360544

  9. 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

  10. Time-resolved spectroscopy of mitochondria, cells and tissues under normal and pathological conditions.

    Science.gov (United States)

    Beauvoit, B; Chance, B

    1998-07-01

    In this study, the detailed dependence of light scattering on tissue architecture and intracellular composition has been investigated. Firstly, we simulated the reduced scattering coefficient (mu(s)') of the rat liver using the Mie theory, the Rayleigh-Debye-Gans approximation and electron microscopy data. Then, the reduced scattering coefficient of isolated rat liver mitochondria, isolated hepatocytes and various rat tissues (i.e. perfused liver, brain, muscle, tumors) was measured at 780 nm by using time-resolved spectroscopy and a sample-substitution protocol. The comparison of the isolated mitochondria data with the isolated hepatocyte and whole liver measurements suggests that the mitochondrial compartment is the primary factor for light propagation in hepatic tissue, thus strengthening the relevance of the preliminary theoretical study. Nevertheless, the possibility that other intracellular components, such as peroxisomes and lysosomes, interfere with light propagation in rat liver is discussed. Finally, we demonstrate that light scattering in normal rat tissues and tumors is roughly proportional to the mitochondrial content, according to estimates of the mitochondrial protein content of the tissues. PMID:9746339

  11. Rapid telomere motions in live human cells analyzed by highly time-resolved microscopy

    Directory of Open Access Journals (Sweden)

    Wang Xueying

    2008-10-01

    Full Text Available Abstract Background Telomeres cap chromosome ends and protect the genome. We studied individual telomeres in live human cancer cells. In capturing telomere motions using quantitative imaging to acquire complete high-resolution three-dimensional datasets every second for 200 seconds, telomere dynamics were systematically analyzed. Results The motility of individual telomeres within the same cancer cell nucleus was widely heterogeneous. One class of internal heterochromatic regions of chromosomes analyzed moved more uniformly and showed less motion and heterogeneity than telomeres. The single telomere analyses in cancer cells revealed that shorter telomeres showed more motion, and the more rapid telomere motions were energy dependent. Experimentally increasing bulk telomere length dampened telomere motion. In contrast, telomere uncapping, but not a DNA damaging agent, methyl methanesulfonate, significantly increased telomere motion. Conclusion New methods for seconds-scale, four-dimensional, live cell microscopic imaging and data analysis, allowing systematic tracking of individual telomeres in live cells, have defined a previously undescribed form of telomere behavior in human cells, in which the degree of telomere motion was dependent upon telomere length and functionality.

  12. Time Resolved Photoluminescence Studies of ZnO and Zn2SnO4 Nanowires for Solar Cells Applications

    Science.gov (United States)

    Yakami, Baichhabi Raj; Mahat, Meg; Chen, Jiajun; Lu, Liyou; Wang, Wenyong; Pikal, Jon M.

    2013-03-01

    Sensitized nanowires (NWs) are a promising option for solar cells. They serve as the support structure for the absorbing centers, provide interfacial charge separation, and transport to the anode. Most work has focused on binary oxides, but ternary oxides have advantages due to flexibility in the properties of the oxide. Here we report on the photoluminescence (PL) and Time Resolved PL (TRPL) of Zinc oxide (ZnO) and Zinc Tin Oxide (ZTO) NWs grown by Chemical Vapor Deposition. The ZnO NWs show strong band gap emission and weak but resolvable defect emission peaks. The PL from the ZTO NWs does not show any band gap emission and absorption measurements confirm that these NWs have a direct forbidden transition. The ZTO NWs do have a board visible emission peak, which is usually attributed defects and oxygen vacancies. TRPL of the band gap emission in ZnO NWs yield a carrier lifetime of 1.4ns. The TRPL of the defect peaks in ZTO NWs are more complicated, showing a multi-exponential decay but with an overall decay rate similar to the ZnO NWs. This indicates that the expected increase in carrier lifetime in the ZTO NWs is not currently realized likely due to defect recombination, and additional optimization of the NW growth process may yield improved performance. DOE

  13. Single-Cell, Time-Resolved Antimicrobial Effects of a Highly Cationic, Random Nylon-3 Copolymer on Live Escherichia coli.

    Science.gov (United States)

    Choi, Heejun; Chakraborty, Saswata; Liu, Runhui; Gellman, Samuel H; Weisshaar, James C

    2016-01-15

    Synthetic random copolymers based on the nylon-3 (β-peptide) backbone show promise as inexpensive antimicrobial agents resistant to proteolysis. We present a time-resolved observational study of the attack of a particular copolymer MM63:CHx37 on single, live Escherichia coli cells. The composition and chain length of MM63:CHx37 (63% cationic subunits, 37% hydrophobic subunits, 35-subunit average length) were optimized to enhance antibacterial activity while minimizing lysis of human red blood cells. For E. coli cells that export GFP to the periplasm, we obtain alternating phase-contrast and green fluorescence images with a time resolution of 12 s over 60 min following initiation of copolymer flow. Within seconds, cells shrink and exhibit the same plasmolysis spaces that occur following abrupt external osmotic upshift. The osmoprotection machinery attempts to replenish cytoplasmic water, but recovery is interrupted by permeabilization of the cytoplasmic membrane (CM) to GFP. Evidently, the highly cationic copolymer and its counterions rapidly translocate across the outer membrane without permeabilizing it to GFP. The CM permeabilization event is spatially localized. Cells whose CM has been permeabilized never recover growth. The minimum inhibitory concentration (MIC) for cells lacking the osmolyte importer ProP is 4-fold smaller than for normal cells, suggesting that osmoprotection is an important survival strategy. In addition, at the time of CM permeabilization, we observe evidence of oxidative stress. The MIC under anaerobic conditions is at least 8-fold larger than under aerobic conditions, further implicating oxidative damage as an important bacteriostatic effect. Once the copolymer reaches the periplasm, multiple growth-halting mechanisms proceed in parallel. PMID:26493221

  14. Locally resolved measurements in a segmented HTPEM fuel cell with straight flow-fields

    Energy Technology Data Exchange (ETDEWEB)

    Siegel, C. [Zentrum fuer BrennstoffzellenTechnik (ZBT), GmbH (Centre for Fuel Cell Technology), Carl-Benz-Str. 201, D-47057 Duisburg (Germany); University of Duisburg-Essen, Institut fuer Energie- und Umweltverfahrenstechnik, Lotharstr. 1, D-47048 Duisburg (Germany); Siegel Schleimer Ingenieurs-Conseils s.a r.l. - Engineering and research, 2A, rue d' Ehlerange, L-3918 Mondercange (Luxembourg); Bandlamudi, G.; Heinzel, A. [Zentrum fuer BrennstoffzellenTechnik (ZBT), GmbH (Centre for Fuel Cell Technology), Carl-Benz-Str. 201, D-47057 Duisburg (Germany); University of Duisburg-Essen, Institut fuer Energie- und Umweltverfahrenstechnik, Lotharstr. 1, D-47048 Duisburg (Germany); Filusch, F. [Zentrum fuer BrennstoffzellenTechnik (ZBT), GmbH (Centre for Fuel Cell Technology), Carl-Benz-Str. 201, D-47057 Duisburg (Germany)

    2011-08-15

    Significant advances have been reported in building and testing of high-temperature polymer electrolyte membrane (HTPEM) fuel cells and stacks during recent years. Quantity distribution measurement techniques (e.g. current density, temperature and electrochemical impedance spectroscopy (EIS)) using segmented cells are commonly used to characterise low-temperature PEM (LTPEM) fuel cells. Performing these measurements at higher temperatures is more difficult and a relatively new process. For this study, a fully operational segmented HTPEM fuel cell using a straight flow-field configuration was designed, constructed and tested. The cathode side bipolar half-plate consisted of 36 exchangeable segments, whereas, the anode side bipolar half-plate was not segmented. The cell was operated at various operating temperatures with various anode gas compositions and air (no backpressure). In addition to the experimental results, a simple computational fluid dynamics model based on COMSOL Multiphysics {sup registered} 3.5a was used to support the observed behaviour during segmented measurements. The computational domain consisted of the cathode side gas channels and the porous media. All of the boundary conditions and gas properties were defined in a manner similar to the experimental investigations. Some of the theoretical results were compared to the experimental results and conclusions were drawn. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Molecular Diversity Subdivides the Adult Forebrain Neural Stem Cell Population

    Science.gov (United States)

    Giachino, Claudio; Basak, Onur; Lugert, Sebastian; Knuckles, Philip; Obernier, Kirsten; Fiorelli, Roberto; Frank, Stephan; Raineteau, Olivier; Alvarez–Buylla, Arturo; Taylor, Verdon

    2014-01-01

    Neural stem cells (NSCs) in the ventricular domain of the subventricular zone (V-SVZ) of rodents produce neurons throughout life while those in humans become largely inactive or may be lost during infancy. Most adult NSCs are quiescent, express glial markers, and depend on Notch signaling for their self-renewal and the generation of neurons. Using genetic markers and lineage tracing, we identified subpopulations of adult V-SVZ NSCs (type 1, 2, and 3) indicating a striking heterogeneity including activated, brain lipid binding protein (BLBP, FABP7) expressing stem cells. BLBP+ NSCs are mitotically active components of pinwheel structures in the lateral ventricle walls and persistently generate neurons in adulthood. BLBP+ NSCs express epidermal growth factor (EGF) receptor, proliferate in response to EGF, and are a major clonogenic population in the SVZ. We also find BLBP expressed by proliferative ventricular and sub-ventricular progenitors in the fetal and postnatal human brain. Loss of BLBP+ stem/progenitor cells correlates with reduced neurogenesis in aging rodents and postnatal humans. These findings of molecular heterogeneity and proliferative differences subdivide the NSC population and have implications for neurogenesis in the forebrain of mammals during aging. PMID:23964022

  16. Resolving dynamics of cell signaling via real-time imaging of the immunological synapse.

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, Mark A.; Pfeiffer, Janet R. (University of New Mexico, Albuquerque, NM); Wilson, Bridget S. (University of New Mexico, Albuquerque, NM); Timlin, Jerilyn Ann; Thomas, James L. (University of New Mexico, Albuquerque, NM); Lidke, Keith A. (University of New Mexico, Albuquerque, NM); Spendier, Kathrin (University of New Mexico, Albuquerque, NM); Oliver, Janet M. (University of New Mexico, Albuquerque, NM); Carroll-Portillo, Amanda (University of New Mexico, Albuquerque, NM); Aaron, Jesse S.; Mirijanian, Dina T.; Carson, Bryan D.; Burns, Alan Richard; Rebeil, Roberto

    2009-10-01

    This highly interdisciplinary team has developed dual-color, total internal reflection microscopy (TIRF-M) methods that enable us to optically detect and track in real time protein migration and clustering at membrane interfaces. By coupling TIRF-M with advanced analysis techniques (image correlation spectroscopy, single particle tracking) we have captured subtle changes in membrane organization that characterize immune responses. We have used this approach to elucidate the initial stages of cell activation in the IgE signaling network of mast cells and the Toll-like receptor (TLR-4) response in macrophages stimulated by bacteria. To help interpret these measurements, we have undertaken a computational modeling effort to connect the protein motion and lipid interactions. This work provides a deeper understanding of the initial stages of cellular response to external agents, including dynamics of interaction of key components in the signaling network at the 'immunological synapse,' the contact region of the cell and its adversary.

  17. Stark-assisted population control of coherent CS(2) 4f and 5p Rydberg wave packets studied by femtosecond time-resolved photoelectron spectroscopy.

    Science.gov (United States)

    Knappenberger, Kenneth L; Lerch, Eliza-Beth W; Wen, Patrick; Leone, Stephen R

    2007-09-28

    A two-color (3+1(')) pump-probe scheme is employed to investigate Rydberg wave packet dynamics in carbon disulfide (CS(2) (*)). The state superpositions are created within the 4f and 5p Rydberg manifolds by three photons of the 400 nm pump pulse, and their temporal evolution is monitored with femtosecond time-resolved photoelectron spectroscopy using an 800 nm ionizing probe pulse. The coherent behavior of the non-stationary superpositions are observed through wavepacket revivals upon ionization to either the upper (12) or lower (32) spin-orbit components of CS(2) (+). The results show clearly that the composition of the wavepacket can be efficiently controlled by the power density of the excitation pulse over a range from 500 GWcm(2) to 10 TWcm(2). The results are consistent with the anticipated ac-Stark shift for 400 nm light and demonstrate an effective method for population control in molecular systems. Moreover, it is shown that Rydberg wavepackets can be formed in CS(2) with excitation power densities up to 10 TWcm(2) without significant fragmentation. The exponential 1e population decay (T(1)) of specific excited Rydberg states are recovered by analysis of the coherent part of the signal. The dissociation lifetimes of these states are typically 1.5 ps. However, a region exhibiting a more rapid decay ( approximately 800 fs) is observed for states residing in the energy range of 74 450-74 550 cm(-1), suggestive of an enhanced surface crossing in this region. PMID:17902914

  18. Biological characteristics of side population cells in a self-established human ovarian cancer cell line

    Science.gov (United States)

    WEI, ZHENTONG; LV, SHUANG; WANG, YISHU; SUN, MEIYU; CHI, GUANGFAN; GUO, JUN; SONG, PEIYE; FU, XIAOYU; ZHANG, SONGLING; LI, YULIN

    2016-01-01

    The aim of the present study was to establish an ovarian cancer (OC) cell line from ascites of an ovarian serous cystadenocarcinoma patient and investigate the biological characteristics of its side population (SP) cells. The OC cell line was established by isolating, purifying and subculturing primary cells from ascites of an ovarian serous cystadenocarcinoma patient (stage IIIc; grade 3). SP and non-SP (NSP) cells were isolated by fluorescence-activated cell sorting and cultured in serum-free medium and soft agar to compare the tumorsphere and colony formation capacities. Furthermore, SP and NSP cell tumorigenesis was examined by subcutaneous and intraperitoneal injection of the cells to non-obese diabetic/severe combined immune deficiency (NOD/SCID) mice. Drug resistance to cisplatin was examined by cell counting kit-8. The OC cell line was successfully established from ascites of an ovarian serous cystadenocarcinoma patient, which exhibited properties similar to primary tumors subsequent to >50 passages and >2 years of culture. The SP cell ratio was 0.38% in the OC cell line, and a similar SP cell ratio (0.39%) was observed when sorted SP cells were cultured for 3 weeks. Compared with NSP cells, SP cells exhibited increased abilities in differentiation and tumorsphere and colony formation, in addition to the formation of xenografted tumors and ascites and metastasis of the tumors in NOD/SCID mice, even at low cell numbers (3.0×103 cells). The xenografted tumors demonstrated histological features similar to primary tumors and expressed the ovarian serous cystadenocarcinoma marker CA125. In addition, SP cells demonstrated a significantly stronger drug resistance to cisplatin compared with NSP and unsorted cells, while treatment with verapamil, an inhibitor of ATP-binding cassette transporters, potently abrogated SP cell drug resistance. In conclusion, the present study verified SP cells from an established OC cell line and characterized the cells with self

  19. Revealing the ultrafast charge carrier dynamics in organo metal halide perovskite solar cell materials using time resolved THz spectroscopy

    Science.gov (United States)

    Ponseca, C. S., Jr.; Sundström, V.

    2016-03-01

    Ultrafast charge carrier dynamics in organo metal halide perovskite has been probed using time resolved terahertz (THz) spectroscopy (TRTS). Current literature on its early time characteristics is unanimous: sub-ps charge carrier generation, highly mobile charges and very slow recombination rationalizing the exceptionally high power conversion efficiency for a solution processed solar cell material. Electron injection from MAPbI3 to nanoparticles (NP) of TiO2 is found to be sub-ps while Al2O3 NPs do not alter charge dynamics. Charge transfer to organic electrodes, Spiro-OMeTAD and PCBM, is sub-ps and few hundreds of ps respectively, which is influenced by the alignment of energy bands. It is surmised that minimizing defects/trap states is key in optimizing charge carrier extraction from these materials.

  20. Color capable sub-pixel resolving optofluidic microscope and its application to blood cell imaging for malaria diagnosis.

    Directory of Open Access Journals (Sweden)

    Seung Ah Lee

    Full Text Available Miniaturization of imaging systems can significantly benefit clinical diagnosis in challenging environments, where access to physicians and good equipment can be limited. Sub-pixel resolving optofluidic microscope (SROFM offers high-resolution imaging in the form of an on-chip device, with the combination of microfluidics and inexpensive CMOS image sensors. In this work, we report on the implementation of color SROFM prototypes with a demonstrated optical resolution of 0.66 µm at their highest acuity. We applied the prototypes to perform color imaging of red blood cells (RBCs infected with Plasmodium falciparum, a particularly harmful type of malaria parasites and one of the major causes of death in the developing world.

  1. Ultrabroadband time-resolved THz spectroscopy of polymer-based solar cells

    DEFF Research Database (Denmark)

    Cooke, David G.; Krebs, Frederik C; Jepsen, Peter Uhd

    2011-01-01

    We have developed ultrabroadband THz spectroscopy in reflection mode for characterization of conductivity dynamics in conductive polymer samples used in organic solar cells. The spectrometer is designed to have a time resolution limited only by the duration of the optical pump pulse, thus enabling...

  2. Control rod examinations in hot cells: actions opened for resolving wear problems

    International Nuclear Information System (INIS)

    Hot cell examinations of worn rodlets, as well as site data evaluation and mechanical computations, have been used to evaluate the residual lifetime of worn RCCAs, considering EDF's present wear management strategy. Further investigations are underway to study vibratory and wear mechanisms; improved components are being tested

  3. Photosensitized production of singlet oxygen: spatially-resolved optical studies in single cells

    DEFF Research Database (Denmark)

    Breitenbach, Thomas; Kuimova, Marina; Gbur, Peter;

    2009-01-01

    Singlet molecular oxygen, O2(a1g), can be created in photosensitized experiments with sub-cellular spatial resolution in a single cell. This cytotoxic species can subsequently be detected by its 1270 nm phosphorescence (a1g X3-g). Cellular responses to the creation of singlet oxygen can be monito...

  4. Nystatin-induced changes in yeast monitored by time-resolved automated single cell electrorotation.

    Science.gov (United States)

    Hölzel, R

    1998-10-23

    A widespread use of electrorotation for the determination of cellular and subcellular properties has been hindered so far by the need for manual recording of cell movements. Therefore a system has been developed that allows the automatic collection of electrorotation spectra of single cells in real time. It employs a hardware based registration of image moments from which object orientation is calculated. Since the camera's video signal is processed without intermediate image storage a high data throughput of about two recordings per second could be achieved independently of image resolution. This made it possible to monitor changes in cell membrane and cytoplasm of the yeast Saccharomyces cerevisiae under the influence of the antibiotic nystatin with a temporal resolution of 3 min. Up to 20 electrorotation spectra of an individual cell could be collected in the frequency range between 1 kHz and 1 GHz. Two distinct events 7 and 75 min after addition of nystatin were observed with a fast increase in membrane permeability accompanied by a nearly simultaneous drop in cytoplasmic conductivity. PMID:9795246

  5. Synchronization of glycolytic oscillations in a yeast cell population

    DEFF Research Database (Denmark)

    Dano, S.; Hynne, F.; De Monte, Silvia;

    2001-01-01

    consequently it cannot be addressed at the level of a single enzyme or a single chemical species. In this paper it is shown how this system in a CSTR (continuous flow stirred tank reactor) can be modelled quantitatively as a population of Stuart-Landau oscillators interacting by exchange of metabolites through......The mechanism of active phase synchronization in a suspension of oscillatory yeast cells has remained a puzzle for almost half a century. The difficulty of the problem stems from the fact that the synchronization phenomenon involves the entire metabolic network of glycolysis and fermentation, and...

  6. Time-resolved functional analysis of acute impairment of frataxin expression in an inducible cell model of Friedreich ataxia

    Directory of Open Access Journals (Sweden)

    Dörte Poburski

    2016-05-01

    Full Text Available Friedreich ataxia is a neurodegenerative disease caused by a GAA triplet repeat expansion in the first intron of the frataxin gene, which results in reduced expression levels of the corresponding protein. Despite numerous animal and cellular models, therapeutic options that mechanistically address impaired frataxin expression are lacking. Here, we have developed a new mammalian cell model employing the Cre/loxP recombination system to induce a homozygous or heterozygous frataxin knockout in mouse embryonic fibroblasts. Induction of Cre-mediated disruption by tamoxifen was successfully tested on RNA and protein levels. After loss of frataxin protein, cell division, aconitase activity and oxygen consumption rates were found to be decreased, while ROS production was increased in the homozygous state. By contrast, in the heterozygous state no such changes were observed. A time-resolved analysis revealed the loss of aconitase activity as an initial event after induction of complete frataxin deficiency, followed by secondarily elevated ROS production and a late increase in iron content. Initial impairments of oxygen consumption and ATP production were found to be compensated in the late state and seemed to play a minor role in Friedreich ataxia pathophysiology. In conclusion and as predicted from its proposed role in iron sulfur cluster (ISC biosynthesis, disruption of frataxin primarily causes impaired function of ISC-containing enzymes, whereas other consequences, including elevated ROS production and iron accumulation, appear secondary. These parameters and the robustness of the newly established system may additionally be used for a time-resolved study of pharmacological candidates in a HTS manner.

  7. Time-resolved functional analysis of acute impairment of frataxin expression in an inducible cell model of Friedreich ataxia.

    Science.gov (United States)

    Poburski, Dörte; Boerner, Josefine Barbara; Koenig, Michel; Ristow, Michael; Thierbach, René

    2016-01-01

    Friedreich ataxia is a neurodegenerative disease caused by a GAA triplet repeat expansion in the first intron of the frataxin gene, which results in reduced expression levels of the corresponding protein. Despite numerous animal and cellular models, therapeutic options that mechanistically address impaired frataxin expression are lacking. Here, we have developed a new mammalian cell model employing the Cre/loxP recombination system to induce a homozygous or heterozygous frataxin knockout in mouse embryonic fibroblasts. Induction of Cre-mediated disruption by tamoxifen was successfully tested on RNA and protein levels. After loss of frataxin protein, cell division, aconitase activity and oxygen consumption rates were found to be decreased, while ROS production was increased in the homozygous state. By contrast, in the heterozygous state no such changes were observed. A time-resolved analysis revealed the loss of aconitase activity as an initial event after induction of complete frataxin deficiency, followed by secondarily elevated ROS production and a late increase in iron content. Initial impairments of oxygen consumption and ATP production were found to be compensated in the late state and seemed to play a minor role in Friedreich ataxia pathophysiology. In conclusion and as predicted from its proposed role in iron sulfur cluster (ISC) biosynthesis, disruption of frataxin primarily causes impaired function of ISC-containing enzymes, whereas other consequences, including elevated ROS production and iron accumulation, appear secondary. These parameters and the robustness of the newly established system may additionally be used for a time-resolved study of pharmacological candidates in a HTS manner. PMID:27106929

  8. Isolation of Side Population Cells and Detection of ABCG2 from SW480

    Institute of Scientific and Technical Information of China (English)

    LIU Hai-guang; PAN Yi-fei; GUO Gui-long; HU Xiao-qu; HUANG Ka-te; ZHANG Xiao-hua

    2007-01-01

    Objective: Side population cells (SP cells) are a new type of stem cells. They mainly express ABCG2/BCRP1 and have the ability to eliminate DNA dye Hoechst33342. Many studies showed that side population cells were able of self-renewal, differentiation and carcinogenesis in cancers. Our investigation aimed at isolation of side population cells and ABCG2 positive subpopulation from colon cancer cell line SW480 and identification of their characteristics of cancer stem cells. Methods: side population cells and non-side population cells of colon cancer cell line SW480 were isolated with DNA dye Hoechst33342 and their cell cycles were measured by flow cytometry. Expression of ABCG2 of SW480 was measured by immunohistochemistry and immunofluorescence, and its proportion was measured by flow cytometry. Results: SW480 contained 2.29% side population cells. The fraction of side population cells decreased greatly to 0.40% by treatment with verapamil. The fraction of side population cells in S-G2M cell cycle was 16.14%, which was much lower than the fraction (34.05%) of non-side population cells in S-G2M. In SW480, ABCG2 positive cells, which proportion was 9.66%, were small, circular or oval, lack of psuedopods, similar to poor differentiation. On the contrary, the ABCG2 negative cells were large, polygonal, with many psuedopods, similar to high differentiation. Conclusion: our assay identified that side population cells did exist in SW480 and had a quiescence characteristic of stem cells. ABCG2 positive subpopulation occupied about 9.66% of SW480 and may have the ability to promote cell self-renewal and inhibit cell differentiation. Therefore, to isolate ABCG2 positive subpopulation from side population cells may be an alternative to study colorectal cancer stem cells.

  9. 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....

  10. Side population cells isolated from KATO Ⅲ human gastric cancer cell line have cancer stem cell-like characteristics

    Institute of Scientific and Technical Information of China (English)

    Jun-Jun She; Peng-Ge Zhang; Xuan Wang; Xiang-Ming Che; Zi-Ming Wang

    2012-01-01

    AIM:To investigate whether the side population (SP)cells possess cancer stem cell-like characteristics in vitro and the role of SP cells in tumorigenic process in gastric cancer.METHODS:We analyzed the presence of SP cells in different human gastric carcinoma cell lines,and then isolated and identified the SP cells from the KATO Ⅲ human gastric cancer cell line by flow cytometry.The clonogenic ability and self-renewal were evaluated by clone and sphere formation assays.The related genes were determined by reverse transcription polymerase chain reaction.To compare tumorigenic ability,SP and non-side population (NSP) cells from the KATO Ⅲ human gastric cancer cell line were subcutaneously injected into nude mice.RESULTS:SP cells from the total population accounted for 0.57% in KATO Ⅲ,1.04% in Hs-746T,and 0.02% in AGS (CRL-1739).SP cells could grow clonally and have self-renewal capability in conditioned media.The expression of ABCG2,MDRI,Bmi-1 and Oct-4 was different between SP and NSP cells.However,there was no apparent difference between SP and NSP cells when they were injected into nude mice.CONCLUSION:SP cells have some cancer stem celllike characteristics in vitro and can be used for studying the tumorigenic process in gastric cancer.

  11. Anti-Erythropoietin Antibody Associated Pure Red Cell Aplasia Resolved after Liver Transplantation

    OpenAIRE

    Hung, Annie K.; Jennifer Guy; Behler, Caroline M.; Lee, Eugene E.

    2015-01-01

    Patients undergoing antiviral therapy for chronic hepatitis C often develop anemia secondary to ribavirin and interferon. Recombinant erythropoietin has been used to improve anemia associated with antiviral therapy and to minimize dose reductions, which are associated with decreased rates of sustained virologic response. A rare potential side effect of recombinant erythropoietin is anti-erythropoietin antibody associated pure red cell aplasia. In chronic kidney disease patients with this enti...

  12. A computational approach to resolve cell level contributions to early glandular epithelial cancer progression

    OpenAIRE

    Park Sunwoo; Mostov Keith; Debnath Jayanta; Kim Sean HJ; Hunt C Anthony

    2009-01-01

    Abstract Background Three-dimensional (3D) embedded cell cultures provide an appropriate physiological environment to reconstruct features of early glandular epithelial cancer. Although these are orders of magnitude simpler than tissues, they too are complex systems that have proven challenging to understand. We used agent-based, discrete event simulation modeling methods to build working hypotheses of mechanisms of epithelial 3D culture phenotype and early cancer progression. Starting with a...

  13. Spectrally resolved annealing effect in P3HT:PCBM organic solar cells

    Czech Academy of Sciences Publication Activity Database

    Purkrt, Adam; Poruba, Aleš; Vaněček, Milan; Goris, L.; Manca, J.

    Dresden : GD Joinr Research Centre, 2006 - (Poortmans, J.; Ossenbrink, H.; Dunlop, E.; Helm, P.), s. 408-411 ISBN 3-936338-20-5. [European Photovoltaic Solar Energy Conference /21./. Dresden (DE), 04.09.2006-08.09.2006] R&D Projects: GA MŠk LC510 Institutional research plan: CEZ:AV0Z10100521 Keywords : organic solar cell * annealing * photoelectric properties Subject RIV: BM - Solid Matter Physics ; Magnetism

  14. Identification and Characterization of Side Population Cells in Human Lung Adenocarcinoma SPC-A1 Cells

    Institute of Scientific and Technical Information of China (English)

    Yan-liang Zhu; Long-bang Chen; Jing-hua Wang; Xin-yi Xia

    2011-01-01

    Objective: There has been an increasing interest in recent years in the role of stem cells.With an extensive understanding of their biology,a major role for stem cells in the malignant process has been proposed and the existence of cancer stem cells(CSCs) has been confirmed in hematopoietic malignancies and solid organ malignancies including brain cancer,breast,prostate,colon,and pancreatic cancer.Lung cancer is the leading cause of cancer mortality in most large cities of China.It is possible that lung cancer contains cancer stem cells responsible for its malignancy.The aim of this study is to identify,characterize and enrich the CSC population that drives and maintains lung adenocarcinoma growth and metastasis.Methods: Side population(SP) cell analysis and sorting were applied on human lung adenocarcinoma cell line and an attempt to further enrich them by preliminary serum-free culture before fluorescence activated cell sorting (FACS) was done.Stem cell properties of SP cells were evaluated by their proliferative index,colony-forming efficiency,tumorigenic potential,bi-differentiation capacity and the expression of common stem cell surface markers.Results: Lung cancer cells could grow in a serum-free Medium(SFM) as non-adherent spheres similar to neurospheres or mammospheres.The proportion of SP cells in cell spheres was significantly higher than that in cells grown as monolayers.SP cells had a greater proliferative index,a higher colony-forming efficiency and a greater ability to form tumor in vivo.SP cells were both CCA positive and SP-C positive while non-SP cells were only SP-C positive.Flow cytometric analysis of cell phenotype showed that SP cells expressed CD133 and CD44,the common cell surface markers of cancer stem cells,while non-SP cells only expressed CD44.Conclusion: SP cells existed in human lung adenocarcinoma cell lines and they could be further enriched by preliminary serum-free culture before FACS sorting.SP cells possessed the properties of

  15. Identification and Characterization of Side Population Cells in Human Lung Adenocarcinoma SPC-A1 Cells

    Institute of Scientific and Technical Information of China (English)

    Yan-liang Zhu; Long-bang Chen; Jing-hua Wang; Xin-yi Xia

    2010-01-01

    Objective:There has been an increasing interest in recent years in the role of stem cells.With an extensive understanding of their biology,a major role for stem cells in the malignant process has been proposed and the existence of cancer stem cells(CSCs)has been confirmed in hematopoietic malignancies and solid organ malignancies including brain cancer,breast,prostate,colon,and pancreatic cancer.Lung cancer is the leading cause of cancer mortality in most large cities of China.It is possible that lung cancer contains cancer stem cells responsible for its malignancy.The aim of this study is to identify,characterize and enrich the CSC population that drives and maintains lung adenocarcinoma growth and metastasis.Methods:Side population(SP)cell analysis and sorting were applied on human lung adenocarcinoma cell line and an attempt to further enrich them by preliminary serum-free culture before fluorescence activated cell sorting(FACS)was done.Stem cell properties of SP cells were evaluated by their proliferative index,colony-forming efficiency,tumorigenic potential,bi-differentiation capacity and the expression of common stem cell surface markers.Results:Lung cancer cells could grow in a serum-free Medium(SFM)as non-adherent spheres similar to neurospheres or mammospheres.The proportion of SP cells in cell spheres was significantly higher than that in cells grown as monolayers.SP cells had a greater proliferative index,a higher colony-forming efficiency and a greater ability to form tumor in vivo.SP cells were both CCA positive and SP-C positive while non-SP cells were only SP-C positive.Flow cytometric analysis of cell phenotype showed that SP cells expressed CD133 and CD44,the common cell surface markers of cancer stem cells,while non-SP cells only expressed CD44.Conclusion:SP cells existed in human lung adenocarcinoma cell lines and they could be further enriched by preliminary serum-free culture before FACS sorting.SP cells possessed the properties of cancer stem

  16. Single-cell protein dynamics reproduce universal fluctuations in cell populations

    CERN Document Server

    Brenner, Naama; Rotella, James S; Salman, Hanna

    2015-01-01

    Protein fluctuations in cell populations have recently been shown to exhibit a universal distribution shape under a broad range of biological realizations. Here, measuring protein content in individual bacteria continuously over ~70 generations, we show that single-cell trajectories fluctuate around their average with the same distribution shape as the population, i.e. their relative fluctuations are ergodic. Analysis of these temporal trajectories reveals that one effective random variable, sampled once each cell cycle, suffices to reconstruct the distribution from the trajectory. This in turn implies that cellular microscopic processes are strongly buffered and population-level protein distributions are insensitive to details of the intracellular dynamics. Probing them thus requires searching for novel universality-breaking experimental perturbations.

  17. Characterization of HIV-Specific CD4+T Cell Responses against Peptides Selected with Broad Population and Pathogen Coverage

    DEFF Research Database (Denmark)

    Buggert, Marcus; Norstrom, Melissa M.; Czarnecki, Chris;

    2012-01-01

    CD4+ T cells orchestrate immunity against viral infections, but their importance in HIV infection remains controversial. Nevertheless, comprehensive studies have associated increase in breadth and functional characteristics of HIV-specific CD4+ T cells with decreased viral load. A major challenge...... for the identification of HIV-specific CD4+ T cells targeting broadly reactive epitopes in populations with diverse ethnic background stems from the vast genomic variation of HIV and the diversity of the host cellular immune system. Here, we describe a novel epitope selection strategy, PopCover, that...... aims to resolve this challenge, and identify a set of potential HLA class II-restricted HIV epitopes that in concert will provide optimal viral and host coverage. Using this selection strategy, we identified 64 putative epitopes (peptides) located in the Gag, Nef, Env, Pol and Tat protein regions of...

  18. Characterization of cancer stem-like cells in the side population cells of human gastric cancer cell line MKN-45

    Institute of Scientific and Technical Information of China (English)

    Hai-hong ZHANG; Ai-zhen CAI; Xue-ming WEI; Li DING; Feng-zhi LI; Ai-ming ZHENG; Da-jiang DAI

    2013-01-01

    Objective:Side population (SP) cells may play a crucial role in tumorigenesis and the recurrence of cancer.Many kinds of cell lines and tissues have demonstrated the presence of SP cells,including several gastric cancer cell lines.This study is aimed to identify the cancer stem-like cells in the SP of gastric cancer cell line MKN-45.Methods:We used fluorescence activated cell sorting (FACS) to sort SP cells in the human gastric carcinoma cell line MKN-45 (cells labeled with Hoechst 33342) and then characterized the cancer stem-like properties of SP cells.Results:This study found that the SP cells had higher clone formation efficiency than major population (MP) cells.Five stemness-related gene expression profiles,including OCT-4,SOX-2,NANOG,CD44,and adenosine triphosphate (ATP)-binding cassette transporters gene ABCG2,were tested in SP and MP cells using quantitative real-time reverse transcription polymerase chain reaction (RT-PCR).Western blot was used to show the difference of protein expression between SP and MP cells.Both results show that there was significantly higher protein expression in SP cells than in MP cells.When inoculated into non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mice,SP cells show higher tumorigenesis tendency than MP cells.Conclusions:These results indicate that SP cells possess cancer stem cell properties and prove that SP cells from MKN-45 are gastric cancer stem-like cells.

  19. A Cell-Signaling Network Temporally Resolves Specific versus Promiscuous Phosphorylation

    Directory of Open Access Journals (Sweden)

    Evgeny Kanshin

    2015-02-01

    Full Text Available If specific and functional kinase- or phosphatase-substrate interactions are optimized for binding compared to promiscuous interactions, then changes in phosphorylation should occur faster on functional versus promiscuous substrates. To test this hypothesis, we designed a high temporal resolution global phosphoproteomics protocol to study the high-osmolarity glycerol (HOG response in the budding yeast Saccharomyces cerevisiae. The method provides accurate, stimulus-specific measurement of phosphoproteome changes, quantitative analysis of phosphodynamics at sub-minute temporal resolution, and detection of more phosphosites. Rates of evolution of dynamic phosphosites were comparable to those of known functional phosphosites and significantly lower than static or longer-time-frame dynamic phosphosites. Kinetic profile analyses indicated that putatively functional kinase- or phosphatase-substrate interactions occur more rapidly, within 60 s, than promiscuous interactions. Finally, we report many changes in phosphorylation of proteins implicated in cytoskeletal and mitotic spindle dynamics that may underlie regulation of cell cycle and morphogenesis.

  20. Cathepsin B-Deficient Mice Resolve Leishmania major Inflammation Faster in a T Cell-Dependent Manner.

    Science.gov (United States)

    Rasid, Orhan; Mériaux, Véronique; Khan, Erin M; Borde, Chloé; Ciulean, Ioana S; Fitting, Catherine; Manoury, Bénédicte; Cavaillon, Jean-Marc; Doyen, Noëlle

    2016-05-01

    A critical role for intracellular TLR9 has been described in recognition and host resistance to Leishmania parasites. As TLR9 requires endolysosomal proteolytic cleavage to achieve signaling functionality, we investigated the contribution of different proteases like asparagine endopeptidase (AEP) or cysteine protease cathepsins B (CatB), L (CatL) and S (CatS) to host resistance during Leishmania major (L. major) infection in C57BL/6 (WT) mice and whether they would impact on TLR9 signaling. Unlike TLR9-/-, which are more susceptible to infection, AEP-/-, CatL-/- and CatS-/- mice are as resistant to L. major infection as WT mice, suggesting that these proteases are not individually involved in TLR9 processing. Interestingly, we observed that CatB-/- mice resolve L. major lesions significantly faster than WT mice, however we did not find evidence for an involvement of CatB on either TLR9-dependent or independent cytokine responses of dendritic cells and macrophages or in the innate immune response to L. major infection. We also found no difference in antigen presenting capacity. We observed a more precocious development of T helper 1 responses accompanied by a faster decline of inflammation, resulting in resolution of footpad inflammation, reduced IFNγ levels and decreased parasite burden. Adoptive transfer experiments into alymphoid RAG2-/-γc-/- mice allowed us to identify CD3+ T cells as responsible for the immune advantage of CatB-/- mice towards L. major. In vitro data confirmed the T cell intrinsic differences between CatB-/- mice and WT. Our study brings forth a yet unappreciated role for CatB in regulating T cell responses during L. major infection. PMID:27182703

  1. Cathepsin B-Deficient Mice Resolve Leishmania major Inflammation Faster in a T Cell-Dependent Manner

    Science.gov (United States)

    Mériaux, Véronique; Khan, Erin M.; Borde, Chloé; Ciulean, Ioana S.; Fitting, Catherine; Manoury, Bénédicte; Cavaillon, Jean-Marc; Doyen, Noëlle

    2016-01-01

    A critical role for intracellular TLR9 has been described in recognition and host resistance to Leishmania parasites. As TLR9 requires endolysosomal proteolytic cleavage to achieve signaling functionality, we investigated the contribution of different proteases like asparagine endopeptidase (AEP) or cysteine protease cathepsins B (CatB), L (CatL) and S (CatS) to host resistance during Leishmania major (L. major) infection in C57BL/6 (WT) mice and whether they would impact on TLR9 signaling. Unlike TLR9-/-, which are more susceptible to infection, AEP-/-, CatL-/- and CatS-/- mice are as resistant to L. major infection as WT mice, suggesting that these proteases are not individually involved in TLR9 processing. Interestingly, we observed that CatB-/- mice resolve L. major lesions significantly faster than WT mice, however we did not find evidence for an involvement of CatB on either TLR9-dependent or independent cytokine responses of dendritic cells and macrophages or in the innate immune response to L. major infection. We also found no difference in antigen presenting capacity. We observed a more precocious development of T helper 1 responses accompanied by a faster decline of inflammation, resulting in resolution of footpad inflammation, reduced IFNγ levels and decreased parasite burden. Adoptive transfer experiments into alymphoid RAG2-/-γc-/- mice allowed us to identify CD3+ T cells as responsible for the immune advantage of CatB-/- mice towards L. major. In vitro data confirmed the T cell intrinsic differences between CatB-/- mice and WT. Our study brings forth a yet unappreciated role for CatB in regulating T cell responses during L. major infection. PMID:27182703

  2. Sickle cell disease in the Kurdish population of northern Iraq.

    Science.gov (United States)

    Al-Allawi, Nasir A S; Jalal, Sana D; Nerwey, Farida F; Al-Sayan, Galawezh O O; Al-Zebari, Sahima S M; Alshingaly, Awny A; Markous, Raji D; Jubrael, Jaladet M S; Hamamy, Hanan

    2012-01-01

    Epidemiological studies have revealed that sickle cell disease patients are clustered in two geographical areas in Iraq, one among the Arabs in the extreme south, another among the Kurdish population in the extreme north, where they constitute major health problems. However, no studies have focused on the genotypes responsible for sickle cell disease or the β-globin gene haplotypes associated with it. For the latter purpose, a total of 103 unrelated Kurdish sickle cell disease patients were evaluated by restriction fragment length polymorphism (RFLP) for the sickle cell mutation, followed by multiplex polymerase chain reaction (PCR) and reverse hybridization for β- and α-thalassemia (β- and α-thal) mutations, whenever indicated. Results showed that the most common genotype was sickle cell anemia (68.0%) followed by Hb S/β(0)-thal and Hb S/β(+)-thal at frequencies of 24.2 and 7.8%, respectively. Eight β-thal mutations were associated with the latter two genotypes including: IVS-II-1 (G>A), IVS-I-110 (G>A), codon 8 (-AA), codon 44 (-C), codon 22 (-7 bp), IVS-I-1 (G>A), codon 30 (G>C) and IVS-I-6 (T>C). In Hb SS patients, the -α(3.7) deletion was documented in 10.0% and was the only α-thal mutation detected. Furthermore, 5' β-globin gene cluster haplotyping of 128 β(S) chromosomes revealed that the most common haplotype seen in 69.5% was the Benin haplotype, followed by the Arab-Indian haplotype in 12.5%. These latter findings closely resemble reports from neighboring Turkey, Syria, Jordan, Lebanon and Mediterranean countries, suggesting a possible common origin, but are in contrast to findings from the Eastern Arabian Peninsula and Iran. PMID:22686351

  3. Human mesenchymal stem cells resolve airway inflammation, hyperreactivity, and histopathology in a mouse model of occupational asthma.

    Science.gov (United States)

    Martínez-González, Itziar; Cruz, Maria-Jesús; Moreno, Rafael; Morell, Ferran; Muñoz, Xavier; Aran, Josep M

    2014-10-01

    Occupational asthma (OA) is characterized by allergic airway inflammation and hyperresponsiveness, leading to progressive airway remodeling and a concomitant decline in lung function. The management of OA remains suboptimal in clinical practice. Thus, establishing effective therapies might overcome the natural history of the disease. We evaluated the ability of human adipose-tissue-derived mesenchymal stem cells (hASCs), either unmodified or engineered to secrete the IL-33 decoy receptor sST2, to attenuate the inflammatory and respiratory symptoms in a previously validated mouse model of OA to ammonium persulfate (AP). Twenty-four hours after a dermal AP sensitization and intranasal challenge regimen, the animals received intravenously 1 × 10(6) cells (either hASCs or hASCs overexpressing sST2) or saline and were analyzed at 1, 3, and 6 days after treatment. The infused hASCs induced an anti-inflammatory and restorative program upon reaching the AP-injured, asthmatic lungs, leading to early reduction of neutrophilic inflammation and total IgE production, preserved alveolar architecture with nearly absent lymphoplasmacytic infiltrates, negligible smooth muscle hyperplasia/hypertrophy in the peribronchiolar areas, and baseline airway hyperreactivity (AHR) to methacholine. Local sST2 overexpression barely increased the substantial efficacy displayed by unmodified hASCs. Thus, hASCs may represent a viable multiaction therapeutic capable to adequately respond to the AP-injured lung environment by resolving inflammation, tissue remodeling, and bronchial hyperresponsiveness typical of OA. PMID:24798370

  4. Clonal cell populations unresponsive to radiosensitization induced by telomerase inhibition

    Energy Technology Data Exchange (ETDEWEB)

    Ju, Yeun-Jin; Shin, Hyun-Jin; Park, Jeong-Eun; Juhn, Kyoung-Mi; Woo, Seon Rang; Kim, Hee-Young; Han, Young-Hoon; Hwang, Sang-Gu; Hong, Sung-Hee; Kang, Chang-Mo [Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of); Yoo, Young-Do [Laboratory of Molecular Cell Biology, Graduate School of Medicine, Korea University College of Medicine, Korea University, Seoul 136-705 (Korea, Republic of); Park, Won-Bong [Division of Natural Science, Seoul Women' s University, Seoul 139-774 (Korea, Republic of); Cho, Myung-Haing [Laboratory of Toxicology, College of Veterinary Medicine, Seoul National University, Seoul (Korea, Republic of); Park, Gil Hong, E-mail: ghpark@korea.ac.kr [Department of Biochemistry, College of Medicine, Korea University, Seoul (Korea, Republic of); Lee, Kee-Ho, E-mail: khlee@kirams.re.kr [Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of)

    2010-11-12

    Research highlights: {yields} In our present manuscript, we have clearly showed an interesting but problematic obstacle of a radiosensitization strategy based on telomerase inhibition by showing that: Clonal population unresponsive to this radiosensitization occasionally arise. {yields} The telomere length of unsensitized clones was reduced, as was that of most sensitized clones. {yields} The unsensitized clones did not show chromosome end fusion which was noted in all sensitized clones. {yields} P53 status is not associated with the occurrence of unsensitized clone. {yields} Telomere end capping in unsensitized clone is operative even under telomerase deficiency. -- Abstract: A combination of a radiotherapeutic regimen with telomerase inhibition is valuable when tumor cells are to be sensitized to radiation. Here, we describe cell clones unresponsive to radiosensitization after telomere shortening. After extensive division of individual transformed clones of mTERC{sup -/-} cells, about 22% of clones were unresponsive to radiosensitization even though telomerase action was inhibited. The telomere lengths of unsensitized mTERC{sup -/-} clones were reduced, as were those of most sensitized clones. However, the unsensitized clones did not exhibit chromosomal end-to-end fusion to the extent noted in all sensitized clones. Thus, a defense mechanism preventing telomere erosion is operative even when telomeres become shorter under conditions of telomerase deficiency, and results in unresponsiveness to the radiosensitization generally mediated by telomere shortening.

  5. Immunophenotyping of immune cell populations in the raccoon (Procyon lotor).

    Science.gov (United States)

    Heinrich, Franziska; Jungwirth, Nicole; Carlson, Regina; Tipold, Andrea; Böer, Michael; Scheibe, Thomas; Molnár, Viktor; von Dörnberg, Katja; Spitzbarth, Ingo; Puff, Christina; Wohlsein, Peter; Baumgärtner, Wolfgang

    2015-12-15

    The raccoon (Procyon lotor) is a highly adaptable carnivore that has rapidly conquered Europe over the last decades and represents a potential candidate as pathogen reservoir, bearing the risk for transmission of infectious agents, as zoonosis or spill-over, to other wild life and domestic animals and man. Comprehensive investigations of infectious diseases in raccoons require a detailed knowledge of the participating immune cell populations. To close this gap of knowledge, various antibodies were tested for cross-reactivity with leukocytes in lymphoid organs and peripheral blood of raccoons using immunohistochemistry and flow cytometry, respectively. Eight out of 16 antibodies, directed against CD3, CD79α, Pax-5, IgG, CD44, MHC class II, myeloid/histiocyte antigen (MAC387), and Iba-1 exhibited a specific immunoreaction with cells in distinct anatomical compartments in formalin-fixed paraffin-embedded lymphoid tissues. Flow cytometric analysis revealed that 7 out of 18 antibodies directed against CD11c, CD14, CD21, CD44, CD79α, MHC class I and II cross-reacted with peripheral blood-derived raccoon leukocytes. Summarized, the usefulness of several cross-reacting antibodies was determined for the characterization of raccoon immune cells in immunohistochemistry and flow cytometry, offering the opportunity to study the raccoon immune system under normal and diseased conditions. PMID:26672912

  6. Clonal cell populations unresponsive to radiosensitization induced by telomerase inhibition

    International Nuclear Information System (INIS)

    Research highlights: → In our present manuscript, we have clearly showed an interesting but problematic obstacle of a radiosensitization strategy based on telomerase inhibition by showing that: Clonal population unresponsive to this radiosensitization occasionally arise. → The telomere length of unsensitized clones was reduced, as was that of most sensitized clones. → The unsensitized clones did not show chromosome end fusion which was noted in all sensitized clones. → P53 status is not associated with the occurrence of unsensitized clone. → Telomere end capping in unsensitized clone is operative even under telomerase deficiency. -- Abstract: A combination of a radiotherapeutic regimen with telomerase inhibition is valuable when tumor cells are to be sensitized to radiation. Here, we describe cell clones unresponsive to radiosensitization after telomere shortening. After extensive division of individual transformed clones of mTERC-/- cells, about 22% of clones were unresponsive to radiosensitization even though telomerase action was inhibited. The telomere lengths of unsensitized mTERC-/- clones were reduced, as were those of most sensitized clones. However, the unsensitized clones did not exhibit chromosomal end-to-end fusion to the extent noted in all sensitized clones. Thus, a defense mechanism preventing telomere erosion is operative even when telomeres become shorter under conditions of telomerase deficiency, and results in unresponsiveness to the radiosensitization generally mediated by telomere shortening.

  7. Time-resolved, nonequilibrium carrier dynamics in Si-on-glass thin films for photovoltaic cells

    International Nuclear Information System (INIS)

    A femtosecond pump–probe spectroscopy method was used to characterize the growth process and transport properties of amorphous silicon-on-glass, thin films, intended as absorbers for photovoltaic cells. We collected normalized transmissivity change (ΔT/T) waveforms and interpreted them using a comprehensive three-rate equation electron trapping and recombination model. Optically excited ∼300–500 nm thick Si films exhibited a bi-exponential carrier relaxation with the characteristic times varying from picoseconds to nanoseconds depending on the film growth process. From our comprehensive trapping model, we could determine that for doped and intrinsic films with very low hydrogen dilution the dominant relaxation mode was carrier trapping; while for intrinsic films with large hydrogen content and some texture, it was the standard electron–phonon cooling. In both cases, the initial nonequilibrium relaxation was followed by Shockley–Read–Hall recombination. An excellent fit between the model and the ΔT/T experimental transients was obtained and a correlation between the Si film growth process, its hydrogen content, and the associated trap concentration was demonstrated. (paper)

  8. Time-resolved, nonequilibrium carrier dynamics in Si-on-glass thin films for photovoltaic cells

    Science.gov (United States)

    Serafini, John; Akbas, Yunus; Crandall, Lucas; Bellman, Robert; Kosik Williams, Carlo; Sobolewski, Roman

    2016-04-01

    A femtosecond pump-probe spectroscopy method was used to characterize the growth process and transport properties of amorphous silicon-on-glass, thin films, intended as absorbers for photovoltaic cells. We collected normalized transmissivity change (ΔT/T) waveforms and interpreted them using a comprehensive three-rate equation electron trapping and recombination model. Optically excited ˜300-500 nm thick Si films exhibited a bi-exponential carrier relaxation with the characteristic times varying from picoseconds to nanoseconds depending on the film growth process. From our comprehensive trapping model, we could determine that for doped and intrinsic films with very low hydrogen dilution the dominant relaxation mode was carrier trapping; while for intrinsic films with large hydrogen content and some texture, it was the standard electron-phonon cooling. In both cases, the initial nonequilibrium relaxation was followed by Shockley-Read-Hall recombination. An excellent fit between the model and the ΔT/T experimental transients was obtained and a correlation between the Si film growth process, its hydrogen content, and the associated trap concentration was demonstrated.

  9. Individualized leukemia cell-population profiles in common B-cell acute lymphoblastic leukemia patients

    Institute of Scientific and Technical Information of China (English)

    Jian-Hua Yu; Jing-Tao Dong; Yong-Qian Jia; Neng-Gang Jiang; Ting-Ting Zeng; Hong Xu; Xian-Ming Mo

    2013-01-01

    Immunophenotype is critical for diagnosing common B-cell acute lymphoblastic leukemia (common ALL) and detecting minimal residual disease.We developed a protocol to explore the immunophenotypic profiles of common ALL based on the expression levels of the antigens associated with B lymphoid development,including IL-7Rα (CD127),cytoplasmic CD79a (cCD79a),CD19,VpreB (CD179a),and slgM,which are successive and essential for progression of B cells along their developmental pathway.Analysis of the immunophenotypes of 48 common ALL cases showed that the immunophenotypic patterns were highly heterogeneous,with the leukemic cell population differing from case to case.Through the comprehensive analysis of immunophenotypic patterns,the profiles of patient-specific composite leukemia cell populations could provide detailed information helpful for the diagnosis,therapeutic monitoring,and individualized therapies for common ALL.

  10. Toward Synthetic Spatial Patterns in Engineered Cell Populations with Chemotaxis.

    Science.gov (United States)

    Duran-Nebreda, Salva; Solé, Ricard V

    2016-07-15

    A major force shaping form and patterns in biology is based in the presence of amplification mechanisms able to generate ordered, large-scale spatial structures out of local interactions and random initial conditions. Turing patterns are one of the best known candidates for such ordering dynamics, and their existence has been proven in both chemical and physical systems. Their relevance in biology, although strongly supported by indirect evidence, is still under discussion. Extensive modeling approaches have stemmed from Turing's pioneering ideas, but further confirmation from experimental biology is required. An alternative possibility is to engineer cells so that self-organized patterns emerge from local communication. Here we propose a potential synthetic design based on the interaction between population density and a diffusing signal, including also directed motion in the form of chemotaxis. The feasibility of engineering such a system and its implications for developmental biology are also assessed. PMID:27009520

  11. 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.

  12. Increasing cell culture population doublings for long-term growth of finite life span human cell cultures

    Science.gov (United States)

    Stampfer, Martha R; Garbe, James C

    2015-02-24

    Cell culture media formulations for culturing human epithelial cells are herein described. Also described are methods of increasing population doublings in a cell culture of finite life span human epithelial cells and prolonging the life span of human cell cultures. Using the cell culture media disclosed alone and in combination with addition to the cell culture of a compound associated with anti-stress activity achieves extended growth of pre-stasis cells and increased population doublings and life span in human epithelial cell cultures.

  13. Increasing cell culture population doublings for long-term growth of finite life span human cell cultures

    Energy Technology Data Exchange (ETDEWEB)

    Stampfer, Martha R.; Garbe, James C.

    2016-06-28

    Cell culture media formulations for culturing human epithelial cells are herein described. Also described are methods of increasing population doublings in a cell culture of finite life span human epithelial cells and prolonging the life span of human cell cultures. Using the cell culture media disclosed alone and in combination with addition to the cell culture of a compound associated with anti-stress activity achieves extended growth of pre-stasis cells and increased population doublings and life span in human epithelial cell cultures.

  14. CD34 defines an osteoprogenitor cell population in mouse bone marrow stromal cells

    DEFF Research Database (Denmark)

    Abdallah, Basem M; Al-Shammary, Asma; Skagen, Peter;

    2015-01-01

    Bone marrow stromal cells (BMSCs, also known as bone marrow-derived mesenchymal stem cells) and their progenitors have been identified based on retrospective functional criteria. CD markers are employed to define cell populations with distinct functional characteristics. However, defining and...... prospective isolation of mouse bone marrow osteoprogenitors....... prospective isolation of BMSCs and committed progenitors are lacking. Here, we compared the transcriptome profile of CD markers expressed at baseline and during the course of osteoblast and adipocyte differentiation of two well-characterized osteogenic-committed murine BMSCs (mBMSC(Bone)) and adipogenic...

  15. A mammary repopulating cell population characterized in mammary anlagen reveals essential mammary stroma for morphogenesis.

    Science.gov (United States)

    Song, Jiazhe; Xue, Kai; She, Ji; Ding, Fangrong; Li, Song; Shangguan, Rulan; Dai, Yunping; Du, Liying; Li, Ning

    2014-09-10

    The cells with mammary repopulating capability can achieve mammary gland morphogenesis in a suitable cellular microenvironment. Using cell surface markers of CD24, CD29 and CD49f, mouse mammary repopulating unit (MRU) has been identified in adult mammary epithelium and late embryonic mammary bud epithelium. However, embryonic MRU remains to be fully characterized at earlier mammary anlagen stage. Here we isolated discrete populations of E14.5 mouse mammary anlagen cells. Only Lin(-)CD24(med)CD29(+) cell population was predicted as E14.5 MRU by examining their capacities of forming mammosphere and repopulating cleared mammary fat pad in vivo. However, when we characterized gene expressions of this E14.5 cell population by comparing with adult mouse MRU (Lin(-)CD24(+)CD29(hi)), the gene profiling of these two cell populations exhibited great differences. Real-time PCR and immunostaining assays uncovered that E14.5 Lin(-)CD24(med)CD29(+) cell population was a heterogeneous stroma-enriched cell population. Then, limiting dilutions and single-cell assays also confirmed that E14.5 Lin(-)CD24(med)CD29(+) cell population possessed low proportion of stem cells. In summary, heterogeneous Lin(-)CD24(med)CD29(+) cell population exhibited mammary repopulating ability in E14.5 mammary anlagen, implying that only suitable mammary stroma could enable mammary gland morphogenesis, which relied on the interaction between rare stem cells and microenvironment. PMID:24954407

  16. IL-25 simultaneously elicits distinct populations of innate lymphoid cells and multipotent progenitor type 2 (MPPtype2) cells

    OpenAIRE

    Saenz, Steven A.; Siracusa, Mark C.; Monticelli, Laurel A.; Ziegler, Carly G. K.; Kim, Brian S.; Brestoff, Jonathan R.; Peterson, Lance W.; Wherry, E. John; Goldrath, Ananda W; Bhandoola, Avinash; Artis, David

    2013-01-01

    The predominantly epithelial cell–derived cytokines IL-25, IL-33, and thymic stromal lymphopoietin (TSLP) can promote CD4+ Th2 cell–dependent immunity, inflammation, and tissue repair at barrier surfaces through the induction of multiple innate immune cell populations. IL-25 and IL-33 were previously shown to elicit four innate cell populations, named natural helper cells, nuocytes, innate type 2 helper cells, and multipotent progenitor type 2 (MPPtype2) cells, now collectively termed group 2...

  17. BRET and Time-resolved FRET strategy to study GPCR oligomerization: from cell lines toward native tissues

    Directory of Open Access Journals (Sweden)

    ThierryDURROUX

    2012-07-01

    Demonstrating the direct interactions between two proteins is not trivial since few techniques present a spatial resolution allowing to conclude to close interactions. Resonance energy transfer (RET strategies are actually the most convenient ones. During the last two decades, two of them, the Bioluminescent Resonance Energy Transfer (BRET and Time-resolved Fluorescence Energy Transfer (TR-FRET have been widely used since they exhibit high signal-to-noise ratio. Most of the experiments based on GPCR labeling have been performed in cell lines and it has been shown that all GPCRs have the propensity to form homo- or hetero-oligomers. However, whether these data can be extrapolated to GPCRs expressed in native tissues and explain receptor functioning in real life, remains an open question. Native tissues impose different constraints since GPCR sequences cannot be modified. Recently a fluorescent ligand-based GPCR labeling strategy combined to TR-FRET approach has been successfully used to prove the existence of GPCR oligomerization in native tissues. Although the RET based strategies are generally quite simple to implement, precautions have to be taken before concluding to the absence or the existence of specific interactions between receptors. For example, one should exclude the possibility of collision of receptors diffusing throughout the membrane leading to a specific FRET signal. We will review the advantages and the limits of different approaches and discuss the consequent perspectives.

  18. Populism

    OpenAIRE

    Abts, Koenraad; van Kessel, Stijn

    2015-01-01

    Populism is a concept applied to a wide range of political movements and actors across the globe. There is, at the same time, considerable confusion about the attributes and manifestation of populism, as well as its impact on democracy. This contribution identifies the defining elements of the populist ideology and discusses the varieties in which populism manifests itself, for instance as a component of certain party families. We finally discuss various normative interpretations of populism,...

  19. Androgen receptor expands the population of cancer stem cells in upper urinary tract urothelial cell carcinoma cells

    Science.gov (United States)

    Chen, Chi-Cheng; Hsieh, Teng-Fu; Huang, Chi-Ping; Yu, Ai-Lin; Chang, Wen-Lin; Shyr, Chih-Rong

    2016-01-01

    Androgen receptor (AR) affects the development and progression of upper urinary tract urothelial cell carcinoma (UUTUC). However, the regulatory mechanism exerted by AR to affect UUTUC cells remains unclear. Here we investigated whether AR promotes UUTUC development and progression, possibly by expanding the population of cancer stem cells (CSCs), which are a particular population of cells within cancer cells responsible for tumor initiation, drug resistance and metastasis. We compared UUTUC cells with or without the addition of AR on their CSC population with flow cytometry, colony formation and sphere formation assay to determine the effect of AR on CSC activity, and real-time PCR was used to detect the expression stemness genes and miRNAs. In vivo tumor formation was evaluated with the implantation of cancer cells in nude mice. We found that the addition of AR in UUTUC cells, significantly increased the population of CSC, clonogenicity, sphere formation and the expression of stemness genes (Oct4, Bmi1 and Nanog), altered CSC-related miRNA profile, as well as promoted epithelial mesenchymal transition (EMT). And AR inhibitor, enzalutamide was shown to suppress AR’s effect on tumorsphere formation. Furthermore, in an immune-deficient mouse model, the addition of AR in UUTUC cells also increased the tumor formation capacity. This study will help us better understand the extent to which AR contributes to UUTUC progression by expanding their CSC population and capacity. Our findings could explain high incidence of UUTUC observed in males. And targeting AR may lead to novel therapeutic approaches for genetically diversified urothelial carcinomas in precision medicine era.

  20. 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

  1. 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.

  2. A population dynamics analysis of the interaction between adaptive regulatory T cells and antigen presenting cells.

    Directory of Open Access Journals (Sweden)

    David Fouchet

    Full Text Available BACKGROUND: Regulatory T cells are central actors in the maintenance of tolerance of self-antigens or allergens and in the regulation of the intensity of the immune response during infections by pathogens. An understanding of the network of the interaction between regulatory T cells, antigen presenting cells and effector T cells is starting to emerge. Dynamical systems analysis can help to understand the dynamical properties of an interaction network and can shed light on the different tasks that can be accomplished by a network. METHODOLOGY AND PRINCIPAL FINDINGS: We used a mathematical model to describe a interaction network of adaptive regulatory T cells, in which mature precursor T cells may differentiate into either adaptive regulatory T cells or effector T cells, depending on the activation state of the cell by which the antigen was presented. Using an equilibrium analysis of the mathematical model we show that, for some parameters, the network has two stable equilibrium states: one in which effector T cells are strongly regulated by regulatory T cells and another in which effector T cells are not regulated because the regulatory T cell population is vanishingly small. We then simulate different types of perturbations, such as the introduction of an antigen into a virgin system, and look at the state into which the system falls. We find that whether or not the interaction network switches from the regulated (tolerant state to the unregulated state depends on the strength of the antigenic stimulus and the state from which the network has been perturbed. CONCLUSION/SIGNIFICANCE: Our findings suggest that the interaction network studied in this paper plays an essential part in generating and maintaining tolerance against allergens and self-antigens.

  3. A descriptive study of plasma cell dyscrasias in Egyptian population

    International Nuclear Information System (INIS)

    Background: Plasma cell dyscrasias (PCDs) refer to a spectrum of disorders characterized by the monoclonal proliferation of lymphoplasmacytic cells in the bone marrow and, sometimes, tissue deposition of monoclonal immunoglobulins or their components. These disorders include multiple myeloma (MM) and Waldenstrom’s macroglobulinemia, as well as rare conditions such as light-chain deposition disease (LCDD) and heavy-chain diseases (HCDs). The worldwide annual incidence of MM is estimated at 86,000, which is approximately 0.8% of all new cancer cases. Purpose: Our retrospective study aims to highlight the immunologic and epidemiological features of PCDs mainly MM in Egyptian patients and compare our results with those of other populations. Methods: Two hundred seventeen Egyptian patients with PCD were enrolled in the study. Serum, urine protein electrophoresis and immunofixation were used to demonstrate M protein. Results: One hundred thirty-eight patients (63.6%) had IgG monoclonal band, 38 patients (17.5%) had IgA, 12 patients (5.5%) had Waldenstrom’s macroglobulinemia (IgM monoclonal band) and 29 patients (13.4%) were light chain myeloma. One hundred fifty-one (70%) were Kappa chain positive and 66 patients (30%) were lumbda positive. Conventional cytogenetics was available for 40 patients; of them12 patients (30%) showed 13q-. Mean OS was 37.5 months (1-84 months). Survival analysis was statistically insignificant according to age, sex and ISS or type of treatment (P value >0.05). Conclusion: Long term follow up is required to further define the role of different therapeutic lines of treatment including ASCT in the various stages of PCD based on OS data.

  4. Isolation of adult human pluripotent stem cells from mesenchymal cell populations and their application to liver damages.

    Science.gov (United States)

    Wakao, Shohei; Kitada, Masaaki; Kuroda, Yasumasa; Dezawa, Mari

    2012-01-01

    We have found a novel type of pluripotent stem cells, Multilineage-differentiating stress enduring (Muse) cells that can be isolated from mesenchymal cell populations. Muse cells are characterized by stress tolerance, expression of pluripotency markers, self-renewal, and the ability to differentiate into endodermal-, mesodermal-, and ectodermal-lineage cells from a single cell, demonstrating that they are pluripotent stem cells. They can be isolated as cells positive for stage-specific embryonic antigen-3, a human pluripotent stem cell marker. Here, we introduce the isolation method for Muse cells and the effect of transplantation of these cells on chronic liver diseases. PMID:22167642

  5. Distinct population of highly malignant cells in a head and neck squamous cell carcinoma cell line established by xenograft model

    Directory of Open Access Journals (Sweden)

    Jan Chia-Ing

    2009-11-01

    Full Text Available Abstract The progression and metastasis of solid tumors, including head and neck squamous cell carcinoma (HNSCC, have been related to the behavior of a small subpopulation of cancer stem cells. Here, we have established a highly malignant HNSCC cell line, SASVO3, from primary tumors using three sequential rounds of xenotransplantation. SASVO3 possesses enhanced tumorigenic ability both in vitro and in vivo. Moreover, SASVO3 exhibits properties of cancer stem cells, including that increased the abilities of sphere-forming, the number of side population cells, the potential of transplanted tumor growth and elevated expression of the stem cell marker Bmi1. Injection of SASVO3 into the tail vein of nude mice resulted in lung metastases. These results are consistent with the postulate that the malignant and/or metastasis potential of HNSCC cells may reside in a stem-like subpopulation.

  6. Characterization of rabbit limbal epithelial side population cells using RNA sequencing and single-cell qRT-PCR.

    Science.gov (United States)

    Kameishi, Sumako; Umemoto, Terumasa; Matsuzaki, Yu; Fujita, Masako; Okano, Teruo; Kato, Takashi; Yamato, Masayuki

    2016-05-01

    Corneal epithelial stem cells reside in the limbus, a transitional zone between the cornea and conjunctiva, and are essential for maintaining homeostasis in the corneal epithelium. Although our previous studies demonstrated that rabbit limbal epithelial side population (SP) cells exhibit stem cell-like phenotypes with Hoechst 33342 staining, the different characteristics and/or populations of these cells remain unclear. Therefore, in this study, we determined the gene expression profiles of limbal epithelial SP cells by RNA sequencing using not only present public databases but also contigs that were created by de novo transcriptome assembly as references for mapping. Our transcriptome data indicated that limbal epithelial SP cells exhibited a stem cell-like phenotype compared with non-SP cells. Importantly, gene ontology analysis following RNA sequencing demonstrated that limbal epithelial SP cells exhibited significantly enhanced expression of mesenchymal/endothelial cell markers rather than epithelial cell markers. Furthermore, single-cell quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) demonstrated that the limbal epithelial SP population consisted of at least two immature cell populations with endothelial- or mesenchymal-like phenotypes. Therefore, our present results may propose the presence of a novel population of corneal epithelial stem cells distinct from conventional epithelial stem cells. PMID:26546824

  7. T Cell Epitope Immunotherapy Induces a CD4+ T Cell Population with Regulatory Activity

    Directory of Open Access Journals (Sweden)

    Verhoef Adrienne

    2005-01-01

    Full Text Available Background Synthetic peptides, representing CD4+ T cell epitopes, derived from the primary sequence of allergen molecules have been used to down-regulate allergic inflammation in sensitised individuals. Treatment of allergic diseases with peptides may offer substantial advantages over treatment with native allergen molecules because of the reduced potential for cross-linking IgE bound to the surface of mast cells and basophils. Methods and Findings In this study we address the mechanism of action of peptide immunotherapy (PIT in cat-allergic, asthmatic patients. Cell-division-tracking dyes, cell-mixing experiments, surface phenotyping, and cytokine measurements were used to investigate immunomodulation in peripheral blood mononuclear cells (PBMCs after therapy. Proliferative responses of PBMCs to allergen extract were significantly reduced after PIT. This was associated with modified cytokine profiles generally characterised by an increase in interleukin-10 and a decrease in interleukin-5 production. CD4+ cells isolated after PIT were able to actively suppress allergen-specific proliferative responses of pretreatment CD4neg PBMCs in co-culture experiments. PIT was associated with a significant increase in surface expression of CD5 on both CD4+ and CD8+ PBMCs. Conclusion This study provides evidence for the induction of a population of CD4+ T cells with suppressor/regulatory activity following PIT. Furthermore, up-regulation of cell surface levels of CD5 may contribute to reduced reactivity to allergen.

  8. Implications of epigenetic variability within a cell population for cell type classification

    Directory of Open Access Journals (Sweden)

    Inna eTabansky

    2015-12-01

    Full Text Available Here we propose a new approach to defining nerve ‘cell types’ in reaction to recent advances in single cell analysis. Among cells previously thought to be equivalent, considerable differences in global gene expression and biased tendencies among differing developmental fates have been demonstrated within multiple lineages. The model of classifying cells into distinct types thus has to be revised to account for this intrinsic variability. A ‘cell type’ could be a group of cells that possess similar, but not necessarily identical properties, variable within a spectrum of epigenetic adjustments that permit its developmental path toward a specific function to be achieved. Thus, the definition of a cell type is becoming more similar to the definition of a species: sharing essential properties with other members of its group, but permitting a certain amount of deviation in aspects that do not seriously impact function. This approach accommodates, even embraces the spectrum of natural variation found in various cell populations and consequently avoids the fallacy of false equivalence. For example, developing neurons will react to their microenvironments with epigenetic changes resulting in slight changes in gene expression and morphology. Addressing the new questions implied here will have significant implications for developmental neurobiology.

  9. The cell-stretcher: A novel device for the mechanical stimulation of cell populations

    Science.gov (United States)

    Seriani, S.; Del Favero, G.; Mahaffey, J.; Marko, D.; Gallina, P.; Long, C. S.; Mestroni, L.; Sbaizero, O.

    2016-08-01

    Mechanical stimulation appears to be a critical modulator for many aspects of biology, both of living tissue and cells. The cell-stretcher, a novel device for the mechanical uniaxial stimulation of populations of cells, is described. The system is based on a variable stroke cam-lever-tappet mechanism which allows the delivery of cyclic stimuli with frequencies of up to 10 Hz and deformation between 1% and 20%. The kinematics is presented and a simulation of the dynamics of the system is shown, in order to compute the contact forces in the mechanism. The cells, following cultivation and preparation, are plated on an ad hoc polydimethylsiloxane membrane which is then loaded on the clamps of the cell-stretcher via force-adjustable magnetic couplings. In order to show the viability of the experimentation and biocompatibility of the cell-stretcher, a set of two in vitro tests were performed. Human epithelial carcinoma cell line A431 and Adult Mouse Ventricular Fibroblasts (AMVFs) from a dual reporter mouse were subject to 0.5 Hz, 24 h cyclic stretching at 15% strain, and to 48 h stimulation at 0.5 Hz and 15% strain, respectively. Visual analysis was performed on A431, showing definite morphological changes in the form of cellular extroflections in the direction of stimulation compared to an unstimulated control. A cytometric analysis was performed on the AMVF population. Results show a post-stimulation live-dead ratio deviance of less than 6% compared to control, which proves that the environment created by the cell-stretcher is suitable for in vitro experimentation.

  10. Spatially-resolved chemical analysis of frozen ice cores by cryo-cell-UV-laser-ablation-ICPMS

    Science.gov (United States)

    Müller, Wolfgang; Della Lunga, Damiano; Rasmussen, Sune O.; Svensson, Anders

    2015-04-01

    High-latitude ice cores have become the master records of late Pleistocene climate variability. Especially the high-resolution data from Greenland of the past ~125 ka reveal a remarkably changeable glacial climate, and these rapid climate oscillations have been shown to take place within a few years only [1, 2]. The requirement for an improvement in spatial resolution in ice core analysis arises from 1) the continuous thinning of annual layers in deep parts of ice cores to below what is routinely resolvable by continuous flow analysis and 2) the concomitant recrystallization of ice that potentially affects the location of impurities and thus the identification of annual layers. We developed a new technique to analyze elemental concentrations at ppb-levels in frozen ice cores at ~100 um (0.1 mm) resolution, which focuses on seasalt and dust tracers (e.g. Na, Mg, Ca, Al, Fe). It utilizes a custom-built, peltier-cooled cryo-sample holder fully compatible with the two-volume Laurin LA-cell of our RESOlution M-50 excimer (193 nm ArF) LA system, which is coupled to an Agilent 7500cs ICPMS, operated in reaction cell gas mode with H2 to eliminate 40Ar and 40Ar16O to access 40Ca and 56Fe [3]. Using 3 x 5 cm strips of ice cores per sample holder, this setup allows elemental concentrations to be acquired using both depth-profiling along (chains of) spots and/or as continuous lateral profiles, following surface cleaning with a major-element-free ceramic blade. Ice crystal boundaries can be observed with transmitted or reflected light illumination. We focus on NGRIP samples from Greenland Stadial 22 (GS22; ~84-88 ka; ~2695-2720 m) with its corresponding transitions. Owing to analysis in frozen ice, we can easily identify - relative to ice crystal boundaries - the location of cation impurities in both clear ice and so-called cloudy bands that are enriched in impurities. We find a remarkable difference in the location of impurities between these different ice domains [4]. Lower

  11. A Retrospective Analysis of Oral Langerhans Cell Histiocytosis in an Iranian Population: a 20-year Evaluation

    OpenAIRE

    Saede Atarbashi Moghadam; Ali Lotfi; Batool Piroozhashemi; Sepideh Mokhtari

    2015-01-01

    Statement of the Problem: Langerhans cell histiocytosis is a rare disease with unknown pathogenesis and is characterized by local or disseminated proliferation of Langerhans cells. There is no previous investigation on prevalence of oral Langerhans cell histiocytosis in Iranian population. Purpose: The purpose of this study was to assess the relative frequency of oral Langerhans cell histiocytosis in an Iranian population and to compare the data with previous reports. Materials and Meth...

  12. Human Lymphoid Tissues Harbor a Distinct CD69+CXCR6+ NK Cell Population.

    Science.gov (United States)

    Lugthart, Gertjan; Melsen, Janine E; Vervat, Carly; van Ostaijen-Ten Dam, Monique M; Corver, Willem E; Roelen, Dave L; van Bergen, Jeroen; van Tol, Maarten J D; Lankester, Arjan C; Schilham, Marco W

    2016-07-01

    Knowledge of human NK cells is based primarily on conventional CD56(bright) and CD56(dim) NK cells from blood. However, most cellular immune interactions occur in lymphoid organs. Based on the coexpression of CD69 and CXCR6, we identified a third major NK cell subset in lymphoid tissues. This population represents 30-60% of NK cells in marrow, spleen, and lymph node but is absent from blood. CD69(+)CXCR6(+) lymphoid tissue NK cells have an intermediate expression of CD56 and high expression of NKp46 and ICAM-1. In contrast to circulating NK cells, they have a bimodal expression of the activating receptor DNAX accessory molecule 1. CD69(+)CXCR6(+) NK cells do not express the early markers c-kit and IL-7Rα, nor killer cell Ig-like receptors or other late-differentiation markers. After cytokine stimulation, CD69(+)CXCR6(+) NK cells produce IFN-γ at levels comparable to CD56(dim) NK cells. They constitutively express perforin but require preactivation to express granzyme B and exert cytotoxicity. After hematopoietic stem cell transplantation, CD69(+)CXCR6(+) lymphoid tissue NK cells do not exhibit the hyperexpansion observed for both conventional NK cell populations. CD69(+)CXCR6(+) NK cells constitute a separate NK cell population with a distinct phenotype and function. The identification of this NK cell population in lymphoid tissues provides tools to further evaluate the cellular interactions and role of NK cells in human immunity. PMID:27226093

  13. Molecular analysis of endothelial progenitor cell (EPC subtypes reveals two distinct cell populations with different identities

    Directory of Open Access Journals (Sweden)

    Simpson David A

    2010-05-01

    Full Text Available Abstract Background The term endothelial progenitor cells (EPCs is currently used to refer to cell populations which are quite dissimilar in terms of biological properties. This study provides a detailed molecular fingerprint for two EPC subtypes: early EPCs (eEPCs and outgrowth endothelial cells (OECs. Methods Human blood-derived eEPCs and OECs were characterised by using genome-wide transcriptional profiling, 2D protein electrophoresis, and electron microscopy. Comparative analysis at the transcript and protein level included monocytes and mature endothelial cells as reference cell types. Results Our data show that eEPCs and OECs have strikingly different gene expression signatures. Many highly expressed transcripts in eEPCs are haematopoietic specific (RUNX1, WAS, LYN with links to immunity and inflammation (TLRs, CD14, HLAs, whereas many transcripts involved in vascular development and angiogenesis-related signalling pathways (Tie2, eNOS, Ephrins are highly expressed in OECs. Comparative analysis with monocytes and mature endothelial cells clusters eEPCs with monocytes, while OECs segment with endothelial cells. Similarly, proteomic analysis revealed that 90% of spots identified by 2-D gel analysis are common between OECs and endothelial cells while eEPCs share 77% with monocytes. In line with the expression pattern of caveolins and cadherins identified by microarray analysis, ultrastructural evaluation highlighted the presence of caveolae and adherens junctions only in OECs. Conclusions This study provides evidence that eEPCs are haematopoietic cells with a molecular phenotype linked to monocytes; whereas OECs exhibit commitment to the endothelial lineage. These findings indicate that OECs might be an attractive cell candidate for inducing therapeutic angiogenesis, while eEPC should be used with caution because of their monocytic nature.

  14. Endothelial Progenitor Cell Fraction Contained in Bone Marrow-Derived Mesenchymal Stem Cell Populations Impairs Osteogenic Differentiation

    Directory of Open Access Journals (Sweden)

    Fabian Duttenhoefer

    2015-01-01

    Full Text Available In bone tissue engineering (TE endothelial cell-osteoblast cocultures are known to induce synergies of cell differentiation and activity. Bone marrow mononucleated cells (BMCs are a rich source of mesenchymal stem cells (MSCs able to develop an osteogenic phenotype. Endothelial progenitor cells (EPCs are also present within BMC. In this study we investigate the effect of EPCs present in the BMC population on MSCs osteogenic differentiation. Human BMCs were isolated and separated into two populations. The MSC population was selected through plastic adhesion capacity. EPCs (CD34+ and CD133+ were removed from the BMC population and the resulting population was named depleted MSCs. Both populations were cultured over 28 days in osteogenic medium (Dex+ or medium containing platelet lysate (PL. MSC population grew faster than depleted MSCs in both media, and PL containing medium accelerated the proliferation for both populations. Cell differentiation was much higher in Dex+ medium in both cases. Real-time RT-PCR revealed upregulation of osteogenic marker genes in depleted MSCs. Higher values of ALP activity and matrix mineralization analyses confirmed these results. Our study advocates that absence of EPCs in the MSC population enables higher osteogenic gene expression and matrix mineralization and therefore may lead to advanced bone neoformation necessary for TE constructs.

  15. flowCL: ontology-based cell population labelling in flow cytometry

    OpenAIRE

    Courtot, Mélanie; Meskas, Justin; Diehl, Alexander D.; Droumeva, Radina; Gottardo, Raphael; Jalali, Adrin; Taghiyar, Mohammad Jafar; Maecker, Holden T; McCoy, J. Philip; Ruttenberg, Alan; Scheuermann, Richard H.; Brinkman, Ryan R

    2014-01-01

    Motivation: Finding one or more cell populations of interest, such as those correlating to a specific disease, is critical when analysing flow cytometry data. However, labelling of cell populations is not well defined, making it difficult to integrate the output of algorithms to external knowledge sources.

  16. Phenotype overlap in glial cell populations: astroglia, oligodendroglia and NG-2(+ cells

    Directory of Open Access Journals (Sweden)

    Robert eFern

    2015-05-01

    Full Text Available The extent to which NG-2(+ cells form a distinct population separate from astrocytes is central to understanding whether this important cell class is wholly an oligodendrocyte precursor cell (OPC or has additional functions akin to those classically ascribed to astrocytes. Early immuno-staining studies indicate that NG-2(+ cells do not express the astrocyte marker GFAP, but orthogonal reconstructions of double-labelled confocal image stacks here reveal a significant degree of co-expression in individual cells within post-natal day 10 (P10 rat optic nerve (RON and rat cortex. Extensive scanning of various antibody/fixation/embedding approaches identified a protocol for selective post-embedded immuno-gold labelling. This first ultrastructural characterization of identified NG-2(+ cells revealed populations of both OPCs and astrocytes in P10 RON. NG-2(+ astrocytes had classic features including the presence of glial filaments but low levels of glial filament expression were also found in OPCs and myelinating oligodendrocytes. P0 RONs contained few OPCs but positively identified astrocytes were observed to ensheath pre-myelinated axons in a fashion previously described as a definitive marker of the oligodendrocyte lineage. Astrocyte ensheathment was also apparent in P10 RONs, was absent from developing nodes of Ranvier and was never associated with compact myelin. Astrocyte processes were also shown to encapsulate some oligodendrocyte somata. The data indicate that common criteria for delineating astrocytes and oligodendroglia are insufficiently robust and that astrocyte features ascribed to OPCs are likely to arise from misidentification.

  17. 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

  18. Side Population Cells from Human Melanoma Tumors Reveal Diverse Mechanisms for Chemoresistance

    OpenAIRE

    Luo, Yuchun; Ellis, Lixia Z; Dallaglio, Katiuscia; Takeda, Moe; Robinson, William A.; Robinson, Steven; Liu, Weimin; Lewis, Karl D.; McCarter, Martin D; Gonzalez, Rene; David A Norris; Roop, Dennis R.; Spritz, Richard A.; Ahn, Natalie G.; Fujita, Mayumi

    2012-01-01

    Side population (SP) is identified as cells capable of excluding the fluorescent Hoechst dye and anticancer drugs, and represents hematopoietic stem cells and chemoresistant cells from several solid tumors. In this study, we confirmed the presence of SP cells in tumors from melanoma patients. Melanoma SP cells overexpressed ATP-binding-cassette (ABC) transporters, ABCB1 and ABCB5. We generated a direct in vivo xenograft model, and demonstrated that SP cells were resistant to paclitaxel, a sub...

  19. flowCL: ontology-based cell population labelling in flow cytometry

    Science.gov (United States)

    Courtot, Mélanie; Meskas, Justin; Diehl, Alexander D.; Droumeva, Radina; Gottardo, Raphael; Jalali, Adrin; Taghiyar, Mohammad Jafar; Maecker, Holden T.; McCoy, J. Philip; Ruttenberg, Alan; Scheuermann, Richard H.; Brinkman, Ryan R.

    2015-01-01

    Motivation: Finding one or more cell populations of interest, such as those correlating to a specific disease, is critical when analysing flow cytometry data. However, labelling of cell populations is not well defined, making it difficult to integrate the output of algorithms to external knowledge sources. Results: We developed flowCL, a software package that performs semantic labelling of cell populations based on their surface markers and applied it to labelling of the Federation of Clinical Immunology Societies Human Immunology Project Consortium lyoplate populations as a use case. Conclusion: By providing automated labelling of cell populations based on their immunophenotype, flowCL allows for unambiguous and reproducible identification of standardized cell types. Availability and implementation: Code, R script and documentation are available under the Artistic 2.0 license through Bioconductor (http://www.bioconductor.org/packages/devel/bioc/html/flowCL.html). Contact: rbrinkman@bccrc.ca Supplementary information: Supplementary data are available at Bioinformatics online. PMID:25481008

  20. A sub-cellular viscoelastic model for cell population mechanics.

    Directory of Open Access Journals (Sweden)

    Yousef Jamali

    Full Text Available Understanding the biomechanical properties and the effect of biomechanical force on epithelial cells is key to understanding how epithelial cells form uniquely shaped structures in two or three-dimensional space. Nevertheless, with the limitations and challenges posed by biological experiments at this scale, it becomes advantageous to use mathematical and 'in silico' (computational models as an alternate solution. This paper introduces a single-cell-based model representing the cross section of a typical tissue. Each cell in this model is an individual unit containing several sub-cellular elements, such as the elastic plasma membrane, enclosed viscoelastic elements that play the role of cytoskeleton, and the viscoelastic elements of the cell nucleus. The cell membrane is divided into segments where each segment (or point incorporates the cell's interaction and communication with other cells and its environment. The model is capable of simulating how cells cooperate and contribute to the overall structure and function of a particular tissue; it mimics many aspects of cellular behavior such as cell growth, division, apoptosis and polarization. The model allows for investigation of the biomechanical properties of cells, cell-cell interactions, effect of environment on cellular clusters, and how individual cells work together and contribute to the structure and function of a particular tissue. To evaluate the current approach in modeling different topologies of growing tissues in distinct biochemical conditions of the surrounding media, we model several key cellular phenomena, namely monolayer cell culture, effects of adhesion intensity, growth of epithelial cell through interaction with extra-cellular matrix (ECM, effects of a gap in the ECM, tensegrity and tissue morphogenesis and formation of hollow epithelial acini. The proposed computational model enables one to isolate the effects of biomechanical properties of individual cells and the

  1. Establishment and characterization of primary lung cancer cell lines from Chinese population

    Institute of Scientific and Technical Information of China (English)

    Chao ZHENG; Yi-hua SUN; Xiao-lei YE; Hai-quan CHEN; Hong-bin JI

    2011-01-01

    Aim: To establish and characterize primary lung cancer cell lines from Chinese population.Methods: Lung cancer specimens or pleural effusions were collected from Chinese lung cancer patients and cultured in vitro with ACL4 medium (for non-small cell lung carcinomas (NSCLC)) or HITES medium (for small cell lung carcinomas (SCLC)) supplemented with 5%FBS. All cell lines were maintained in culture for more than 25 passages. Most of these cell lines were further analyzed for oncogenic mutations, karyotype, cell growth kinetics, and tumorigenicity in nude mice.Results: Eight primary cell lines from Chinese lung cancer patients were established and characterized, including seven NSCLC cell lines and one SCLC cell line. Five NSCLC cell lines were found to harbor epidermal growth factor receptor (EGFR) kinase domain mutations.Conclusion: These well-characterized primary lung cancer cell lines from Chinese population provide a unique platform for future studies of the ethnic differences in lung cancer biology and drug response.

  2. Risk Factors for Renal Cell Cancer in a Japanese Population

    OpenAIRE

    Washio, Masakazu; Mori, Mitsuru

    2009-01-01

    The incidence of renal cell cancer has been increasing worldwide. Although the incidence of renal cell cancer in Japan is lower than the rates in the other industrialized countries, there is no doubt that it is increasing. In this paper, we would like to introduce the result of our studies, which evaluate the risk factors for renal cell cancer in Japan. Hypertension, diabetes mellitus, kidney diseases, fondness for fatty food and black tea showed an increased risk of renal cell carcinoma whil...

  3. Lin28a is a putative factor in regulating cancer stem cell-like properties in side population cells of oral squamous cell carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, S.; Tanaka, J.; Okada, S.; Isobe, T.; Yamamoto, G.; Yasuhara, R.; Irie, T.; Akiyama, C.; Kohno, Y.; Tachikawa, T.; Mishima, K., E-mail: mishima-k@dent.showa-u.ac.jp

    2013-05-01

    Cancer stem cells (CSCs) are among the target cells of cancer therapy because they are uniquely involved in both cancer progression and sensitivity to chemotherapeutic agents. We identified side population (SP) cells, which are known to be an enriched population of CSC, in five oral squamous cell carcinoma (OSCC) cells (SCC9, SCC25, TOSCC7, TOSCC17, and TOSCC23). The percentages of SP cells ranged from 0% to 3.3%, with TOSCC23 cells showing the highest percentages of SP cells (3.3% of the total cell population). The SP cells isolated from TOSCC23 cells also showed greater cell proliferation and invasion compared to non-SP (MP) cells. Therefore, our initial findings suggested that SP cells were enriched for CSC-like cells. Furthermore, DNA microarray analysis revealed that the expression of cell proliferation-related and anti-apoptotic genes was greater in SP cells compared to MP cells. We focused on Lin28a, which showed the highest expression (approximately 22-fold) among the upregulated genes. The overexpression of Lin28a in TOSCC23 cells increased their proliferation, colony formation, and invasion. These findings suggest that Lin28a is an appropriate CSC target molecule for OSCC treatment - Highlights: ► Lin28a is a SP cell-specific factor in oral squamous cell carcinoma (OSCC) cells. ► SP cells in OSCC cells show cancer stem cell-like properties. ► Lin28a regulates OSCC proliferative and invasive activities.

  4. Lin28a is a putative factor in regulating cancer stem cell-like properties in side population cells of oral squamous cell carcinoma

    International Nuclear Information System (INIS)

    Cancer stem cells (CSCs) are among the target cells of cancer therapy because they are uniquely involved in both cancer progression and sensitivity to chemotherapeutic agents. We identified side population (SP) cells, which are known to be an enriched population of CSC, in five oral squamous cell carcinoma (OSCC) cells (SCC9, SCC25, TOSCC7, TOSCC17, and TOSCC23). The percentages of SP cells ranged from 0% to 3.3%, with TOSCC23 cells showing the highest percentages of SP cells (3.3% of the total cell population). The SP cells isolated from TOSCC23 cells also showed greater cell proliferation and invasion compared to non-SP (MP) cells. Therefore, our initial findings suggested that SP cells were enriched for CSC-like cells. Furthermore, DNA microarray analysis revealed that the expression of cell proliferation-related and anti-apoptotic genes was greater in SP cells compared to MP cells. We focused on Lin28a, which showed the highest expression (approximately 22-fold) among the upregulated genes. The overexpression of Lin28a in TOSCC23 cells increased their proliferation, colony formation, and invasion. These findings suggest that Lin28a is an appropriate CSC target molecule for OSCC treatment - Highlights: ► Lin28a is a SP cell-specific factor in oral squamous cell carcinoma (OSCC) cells. ► SP cells in OSCC cells show cancer stem cell-like properties. ► Lin28a regulates OSCC proliferative and invasive activities

  5. Coarse-grained analysis of stochastically simulated cell populations with a positive feedback genetic network architecture.

    Science.gov (United States)

    Aviziotis, I G; Kavousanakis, M E; Bitsanis, I A; Boudouvis, A G

    2015-06-01

    Among the different computational approaches modelling the dynamics of isogenic cell populations, discrete stochastic models can describe with sufficient accuracy the evolution of small size populations. However, for a systematic and efficient study of their long-time behaviour over a wide range of parameter values, the performance of solely direct temporal simulations requires significantly high computational time. In addition, when the dynamics of the cell populations exhibit non-trivial bistable behaviour, such an analysis becomes a prohibitive task, since a large ensemble of initial states need to be tested for the quest of possibly co-existing steady state solutions. In this work, we study cell populations which carry the lac operon network exhibiting solution multiplicity over a wide range of extracellular conditions (inducer concentration). By adopting ideas from the so-called "equation-free" methodology, we perform systems-level analysis, which includes numerical tasks such as the computation of coarse steady state solutions, coarse bifurcation analysis, as well as coarse stability analysis. Dynamically stable and unstable macroscopic (population level) steady state solutions are computed by means of bifurcation analysis utilising short bursts of fine-scale simulations, and the range of bistability is determined for different sizes of cell populations. The results are compared with the deterministic cell population balance model, which is valid for large populations, and we demonstrate the increased effect of stochasticity in small size populations with asymmetric partitioning mechanisms. PMID:24929336

  6. Coculture with endothelial cells reduces the population of cycling LeX neural precursors but increases that of quiescent cells with a side population phenotype

    International Nuclear Information System (INIS)

    Neural stem cell proliferation and differentiation are regulated by external cues from their microenvironment. As endothelial cells are closely associated with neural stem cell in brain germinal zones, we investigated whether endothelial cells may interfere with neurogenesis. Neural precursor cells (NPC) from telencephalon of EGFP mouse embryos were cocultured in direct contact with endothelial cells. Endothelial cells did not modify the overall proliferation and apoptosis of neural cells, albeit they transiently delayed spontaneous apoptosis. These effects appeared to be specific to endothelial cells since a decrease in proliferation and a raise in apoptosis were observed in cocultures with fibroblasts. Endothelial cells stimulated the differentiation of NPC into astrocytes and into neurons, whereas they reduced differentiation into oligodendrocytes in comparison to adherent cultures on polyornithine. Determination of NPC clonogenicity and quantification of LeX expression, a marker for NPC, showed that endothelial cells decreased the number of cycling NPC. On the other hand, the presence of endothelial cells increased the number of neural cells having 'side population' phenotype, another marker reported on NPC, which we have shown to contain quiescent cells. Thus, we show that endothelial cells may regulate neurogenesis by acting at different level of NPC differentiation, proliferation and quiescence

  7. Chase-and-run between adjacent cell populations promotes directional collective migration

    Science.gov (United States)

    Theveneau, Eric; Steventon, Benjamin; Scarpa, Elena; Garcia, Simon; Trepat, Xavier; Streit, Andrea; Mayor, Roberto

    2016-01-01

    Collective cell migration in morphogenesis and cancer progression often involves the coordination of multiple cell types. How reciprocal interactions between adjacent cell populations lead to new emergent behaviours remains unknown. Here we studied the interaction between Neural Crest (NC) cells, a highly migratory cell population, and placodal cells, an epithelial tissue that contributes to sensory organs. We found that NC cells “chase” placodal cells by chemotaxis, while placodal cells “run” when contacted by NC. Chemotaxis to Sdf1 underlies the chase, while repulsion involving PCP and N-Cadherin signalling is responsible for the run. This “chase-and-run” requires the generation of asymmetric forces, which depend on local inhibition of focal adhesions. The cell interactions described here are essential for correct NC migration and for segregation of placodes in vivo and are likely to represent a general mechanism of coordinated migration. PMID:23770678

  8. 3-Bromopyruvate inhibits cell proliferation and induces apoptosis in CD133+ population in human glioma.

    Science.gov (United States)

    Xu, Dong-Qiang; Tan, Xiao-Yu; Zhang, Bao-Wei; Wu, Tao; Liu, Ping; Sun, Shao-Jun; Cao, Yin-Guang

    2016-03-01

    The study was aimed to investigate the role of 3-bromopyruvate in inhibition of CD133+ U87 human glioma cell population growth. The results demonstrated that 3-bromopyruvate inhibited the viability of both CD133+ and parental cells derived from U87 human glioma cell line. However, the 3-bromopyruvate-induced inhibition in viability was more prominent in CD133+ cells at 10 μM concentration after 48 h. Treatment of CD133+ cells with 3-bromopyruvate caused reduction in cell population and cell size, membrane bubbling, and degradation of cell membranes. Hoechst 33258 staining showed condensation of chromatin material and fragmentation of DNA in treated CD133+ cells after 48 h. 3-Bromopyruvate inhibited the migration rate of CD133+ cells significantly compared to the parental cells. Flow cytometry revealed that exposure of CD133+ cells to 3-bromopyruvate increased the cell population in S phase from 24.5 to 37.9 % with increase in time from 12 to 48 h. In addition, 3-bromopyruvate significantly enhanced the expression of Bax and cleaved caspase 3 in CD133+ cells compared to the parental cells. Therefore, 3-bromopyruvate is a potent chemotherapeutic agent for the treatment of glioma by targeting stem cells selectively. PMID:26453119

  9. Awareness of Stem cells & Health Implications of SHED found in Pediatric Dentition among Indian Population

    OpenAIRE

    Goomer, Pallvi; Sidhu, Arshpreet Kaur; Tuli, Preety; Kansal, Shinam; Bansal, Kanishka; Thakre, Gauri R

    2014-01-01

    Background: Primary teeth may be an ideal source of postnatal stem cells to regenerate tooth structures and bone, and possibly to treat neural tissue injury or degenerative diseases. SHED (stem cells from human exfoliated deciduous teeth) were identified to be a population of highly proliferative, clonogenic cells capable of differentiating into a variety of cell types including neural cells, adipocytes, and odontoblasts. The present study was carried out to assess the knowledge, awareness...

  10. RESOLVE Project

    Science.gov (United States)

    Parker, Ray; Coan, Mary; Cryderman, Kate; Captain, Janine

    2013-01-01

    The RESOLVE project is a lunar prospecting mission whose primary goal is to characterize water and other volatiles in lunar regolith. The Lunar Advanced Volatiles Analysis (LAVA) subsystem is comprised of a fluid subsystem that transports flow to the gas chromatograph - mass spectrometer (GC-MS) instruments that characterize volatiles and the Water Droplet Demonstration (WDD) that will capture and display water condensation in the gas stream. The LAVA Engineering Test Unit (ETU) is undergoing risk reduction testing this summer and fall within a vacuum chamber to understand and characterize component and integrated system performance. Testing of line heaters, printed circuit heaters, pressure transducers, temperature sensors, regulators, and valves in atmospheric and vacuum environments was done. Test procedures were developed to guide experimental tests and test reports to analyze and draw conclusions from the data. In addition, knowledge and experience was gained with preparing a vacuum chamber with fluid and electrical connections. Further testing will include integrated testing of the fluid subsystem with the gas supply system, near-infrared spectrometer, WDD, Sample Delivery System, and GC-MS in the vacuum chamber. This testing will provide hands-on exposure to a flight forward spaceflight subsystem, the processes associated with testing equipment in a vacuum chamber, and experience working in a laboratory setting. Examples of specific analysis conducted include: pneumatic analysis to calculate the WDD's efficiency at extracting water vapor from the gas stream to form condensation; thermal analysis of the conduction and radiation along a line connecting two thermal masses; and proportional-integral-derivative (PID) heater control analysis. Since LAVA is a scientific subsystem, the near-infrared spectrometer and GC-MS instruments will be tested during the ETU testing phase.

  11. Towards a Novel Spatially-Resolved Hemolysis Detection Method Using a Fluorescent Indicator and Loaded Ghost Cells: Proof-of-Principle.

    Science.gov (United States)

    Jansen, Sebastian V; Müller, Indra; Kiesendahl, Nicole; Schmitz-Rode, Thomas; Steinseifer, Ulrich

    2015-09-01

    It is of the utmost importance to reduce flow-induced hemolysis in devices such as heart-valve prostheses and blood pumps. Thus, in vitro measurements of hemolysis are performed in order to optimize their design in this regard. However, with existing measurement methods, hemolysis can only be assessed as an integrated value over the complete test-circuit. Currently, there are no spatially-resolved in vitro hemolysis measurement techniques known to the authors that would allow for a determination of the critical regions within a device. In this study, a novel spatially-resolved measurement principle is proposed. Ghost cells (i.e. erythrocytes with a lower hemoglobin concentration) were loaded with a calcium-dicitrato complex, and a fluorescent calcium indicator was suspended in the extracellular medium. Calcium and indicator are separated until the cell membrane ruptures (i.e. hemolysis occurs). In the moment of hemolysis, the two compounds bind to each other and emit a fluorescent signal that can be recorded and spatially-resolved in a setup very similar to a standard Particle Image Velocimetry measurement. A proof-of-principle experiment was performed by intentionally inducing hemolysis in a flow-model with a surfactant. The surfactant-induced hemolysis demonstrated a clear increase of the fluorescent signal compared to that of a negative reference. Furthermore, the signal was spatially restricted to the area of hemolysis. Although further challenges need to be addressed, a successful proof-of-principle for novel spatially-resolved hemolysis detection is presented. This method can contribute to better design optimization of devices with respect to flow-induced hemolysis. PMID:26577368

  12. Development of some intestinal endocrine cell populations in water buffalo

    Directory of Open Access Journals (Sweden)

    L. Castaldo

    2010-02-01

    Full Text Available The occurrence and distribution of different endocrine cell types in the gastrointestinal tract of large and small domestic mammals have been extensively studied (Ceccarelli et al. 1995; Agungpriyono et al.2000. Some studies have been also carried out on the ontogeny of gut endocrine cells in mammals (Ono et al. 1994, and only few in ruminant. (Kitamura et al. 1985; Guilloteau et al. 1997. In order to complete a previous study regarding postnatal development of intestinal endocrine cells (Lucini et al. 1999, in this study we report the appearance and distribution of some endocrine cell types in the gut of water buffalo during foetal development.

  13. 75 FR 54351 - Cell and Gene Therapy Clinical Trials in Pediatric Populations; Public Workshop

    Science.gov (United States)

    2010-09-07

    ... HUMAN SERVICES Food and Drug Administration Cell and Gene Therapy Clinical Trials in Pediatric... public workshop entitled ``Cell and Gene Therapy Clinical Trials in Pediatric Populations.'' The purpose... therapy clinical researchers, and other stakeholders regarding best practices related to cell and...

  14. Chemical state of Ag in Conducting Bridge Random Access Memory cells: a depth resolved X-ray Absorption Spectroscopy investigation.

    Science.gov (United States)

    d'Acapito, F.; Souchier, E.; Noe, P.; Blaise, P.; Bernard, M.; Jousseaume, V.

    2016-05-01

    Conducting Bridge Random Access Memories (CBRAM) are a promising substitute for FLASH technology but problems with limited retention of the low resistance ON state still hamper their massive deployment. Depth resolved X-ray Absorption Spectroscopy has been used to describe the chemical state of the atoms of the active electrode (in this case Ag) and to reveal the role of Sb as stabilizer of the metallic state.

  15. Regeneration of transplanted intact cell populations in lethally irradiated hydra

    International Nuclear Information System (INIS)

    A single irradiation of the hydra Pelmatohydra robusta with 0.4 to 10 kR of x rays induced no lethal effects at all, while animals exposed to 40 kR ceased to produce a bud within 24 hr and died within a limited period of time, varying from 10 to 14 days at 250C, and from 28 to 50 days at 100C. This lethal dose of x rays inhibited the proliferation of the cells completely and destroyed interstitial cells. When a small cell mass, which was too small to regenerate alone, was transplanted from the subhypostomal region of an intact animal into the subhypostomal region of the irradiated hydra, the recipient began to produce buds by the proliferation of the graft cells. However, the transplantation of intact peduncle tissue, in which mitotic figures and interstitial cells rarely occurred, failed to produce new buds

  16. RESOLVE Project

    Science.gov (United States)

    Parker, Ray O.

    2012-01-01

    The RESOLVE project is a lunar prospecting mission whose primary goal is to characterize water and other volatiles in lunar regolith. The Lunar Advanced Volatiles Analysis (LAVA) subsystem is comprised of a fluid subsystem that transports flow to the gas chromatograph- mass spectrometer (GC-MS) instruments that characterize volatiles and the Water Droplet Demonstration (WDD) that will capture and display water condensation in the gas stream. The LAVA Engineering Test Unit (ETU) is undergoing risk reduction testing this summer and fall within a vacuum chamber to understand and characterize C!Jmponent and integrated system performance. Ray will be assisting with component testing of line heaters, printed circuit heaters, pressure transducers, temperature sensors, regulators, and valves in atmospheric and vacuum environments. He will be developing procedures to guide these tests and test reports to analyze and draw conclusions from the data. In addition, he will gain experience with preparing a vacuum chamber with fluid and electrical connections. Further testing will include integrated testing of the fluid subsystem with the gas supply system, near-infrared spectrometer, WDD, Sample Delivery System, and GC-MS in the vacuum chamber. This testing will provide hands-on exposure to a flight forward spaceflight subsystem, the processes associated with testing equipment in a vacuum chamber, and experience working in a laboratory setting. Examples of specific analysis Ray will conduct include: pneumatic analysis to calculate the WOO's efficiency at extracting water vapor from the gas stream to form condensation; thermal analysis of the conduction and radiation along a line connecting two thermal masses; and proportional-integral-derivative (PID) heater control analysis. In this Research and Technology environment, Ray will be asked to problem solve real-time as issues arise. Since LAVA is a scientific subsystem, Ray will be utilizing his chemical engineering background to

  17. Repeated cisplatin treatment can lead to a multiresistant tumor cell population with stem cell features and sensitivity to 3-bromopyruvate

    OpenAIRE

    Wintzell, My; Löfstedt, Lina; Johansson, Joel; Pedersen, Anne B.; Fuxe, Jonas; Shoshan, Maria

    2012-01-01

    Cisplatin is used in treatment of several types of cancer, including epithelial ovarian carcinoma (EOC). In order to mimic clinical treatment and to investigate longterm effects of cisplatin in surviving cancer cells, two EOC cell lines were repeatedly treated with low doses. In the SKOV-3 cell line originating from malignant ascites, but not in A2780 cells from a primary tumor, this led to emergence of a stable population (SKOV-3-R) which in the absence of cisplatin showed increased motility...

  18. A single dividing cell population with imbalanced fate drives oesophageal tumour growth.

    Science.gov (United States)

    Frede, Julia; Greulich, Philip; Nagy, Tibor; Simons, Benjamin D; Jones, Philip H

    2016-09-01

    Understanding the cellular mechanisms of tumour growth is key for designing rational anticancer treatment. Here we used genetic lineage tracing to quantify cell behaviour during neoplastic transformation in a model of oesophageal carcinogenesis. We found that cell behaviour was convergent across premalignant tumours, which contained a single proliferating cell population. The rate of cell division was not significantly different in the lesions and the surrounding epithelium. However, dividing tumour cells had a uniform, small bias in cell fate so that, on average, slightly more dividing than non-dividing daughter cells were generated at each round of cell division. In invasive cancers induced by Kras(G12D) expression, dividing cell fate became more strongly biased towards producing dividing over non-dividing cells in a subset of clones. These observations argue that agents that restore the balance of cell fate may prove effective in checking tumour growth, whereas those targeting cycling cells may show little selectivity. PMID:27548914

  19. Differentiation of Effector CD4 T Cell Populations*

    OpenAIRE

    Zhu, Jinfang; Yamane, Hidehiro; Paul, William E.

    2010-01-01

    CD4 T cells play critical roles in mediating adaptive immunity to a variety of pathogens. They are also involved in autoimmunity, asthma, and allergic responses as well as in tumor immunity. During TCR activation in a particular cytokine milieu, naive CD4 T cells may differentiate into one of several lineages of T helper (Th) cells, including Th1, Th2, Th17, and iTreg, as defined by their pattern of cytokine production and function. In this review, we summarize the discovery, functions, and r...

  20. Merging Mixture Components for Cell Population Identification in Flow Cytometry

    Directory of Open Access Journals (Sweden)

    Greg Finak

    2009-01-01

    Full Text Available We present a framework for the identification of cell subpopulations in flow cytometry data based on merging mixture components using the flowClust methodology. We show that the cluster merging algorithm under our framework improves model fit and provides a better estimate of the number of distinct cell subpopulations than either Gaussian mixture models or flowClust, especially for complicated flow cytometry data distributions. Our framework allows the automated selection of the number of distinct cell subpopulations and we are able to identify cases where the algorithm fails, thus making it suitable for application in a high throughput FCM analysis pipeline. Furthermore, we demonstrate a method for summarizing complex merged cell subpopulations in a simple manner that integrates with the existing flowClust framework and enables downstream data analysis. We demonstrate the performance of our framework on simulated and real FCM data. The software is available in the flowMerge package through the Bioconductor project.

  1. Indium 111 white blood cell scanning in the pediatric population

    International Nuclear Information System (INIS)

    Indium-111 leukocyte scanning is a reliable means of locating acute infection in adults, but its use in the pediatric population has not been extensively documented. The results of scans on 30 children retrospectively reviewed are presented. Acute infections were detected in 15 to 16 patients (94% sensitivity) with one false negative scan. There were 8 truly negative and 6 falsely positive studies (57% specificity). (orig.)

  2. Connecting multiple spatial scales to decode the population activity of grid cells

    OpenAIRE

    Stemmler, Martin; Mathis, Alexander; Andreas V. M Herz

    2015-01-01

    Mammalian grid cells fire when an animal crosses the points of an imaginary hexagonal grid tessellating the environment. We show how animals can navigate by reading out a simple population vector of grid cell activity across multiple spatial scales, even though neural activity is intrinsically stochastic. This theory of dead reckoning explains why grid cells are organized into discrete modules within which all cells have the same lattice scale and orientation. The lattice scale changes from m...

  3. Squamous cell carcinoma of the external auditory canal in a patient with non-resolving ear discharge

    OpenAIRE

    N. Zainuddin; Abdullah, O

    2015-01-01

    Discharging ear is a common symptom in the primary care and private general clinics. Most of the cases are treated with the antibiotic ear drops for otitis externa or otitis media. However, despite an adequate standard therapy, a malignant tumour can also be present with non-specific symptom such as ear discharge, especially in the case of persistent ear discharge. In this paper we have reported a case of an adult woman presented with non-resolving ear discharge who was treated repeatedly wit...

  4. Stem cell-like differentiation potentials of endometrial side population cells as revealed by a newly developed in vivo endometrial stem cell assay.

    Directory of Open Access Journals (Sweden)

    Kaoru Miyazaki

    Full Text Available BACKGROUND: Endometrial stem/progenitor cells contribute to the cyclical regeneration of human endometrium throughout a woman's reproductive life. Although the candidate cell populations have been extensively studied, no consensus exists regarding which endometrial population represents the stem/progenitor cell fraction in terms of in vivo stem cell activity. We have previously reported that human endometrial side population cells (ESP, but not endometrial main population cells (EMP, exhibit stem cell-like properties, including in vivo reconstitution of endometrium-like tissues when xenotransplanted into immunodeficient mice. The reconstitution efficiency, however, was low presumably because ESP cells alone could not provide a sufficient microenvironment (niche to support their stem cell activity. The objective of this study was to establish a novel in vivo endometrial stem cell assay employing cell tracking and tissue reconstitution systems and to examine the stem cell properties of ESP through use of this assay. METHODOLOGY/PRINCIPAL FINDINGS: ESP and EMP cells isolated from whole endometrial cells were infected with lentivirus to express tandem Tomato (TdTom, a red fluorescent protein. They were mixed with unlabeled whole endometrial cells and then transplanted under the kidney capsule of ovariectomized immunodeficient mice. These mice were treated with estradiol and progesterone for eight weeks and nephrectomized. All of the grafts reconstituted endometrium-like tissues under the kidney capsules. Immunofluorescence revealed that TdTom-positive cells were significantly more abundant in the glandular, stromal, and endothelial cells of the reconstituted endometrium in mice transplanted with TdTom-labeled ESP cells than those with TdTom-labeled EMP cells. CONCLUSIONS/SIGNIFICANCE: We have established a novel in vivo endometrial stem cell assay in which multi-potential differentiation can be identified through cell tracking during in vivo

  5. Niche-dependent development of functional neuronal networks from embryonic stem cell-derived neural populations

    Directory of Open Access Journals (Sweden)

    Siebler Mario

    2009-08-01

    Full Text Available Abstract Background The present work was performed to investigate the ability of two different embryonic stem (ES cell-derived neural precursor populations to generate functional neuronal networks in vitro. The first ES cell-derived neural precursor population was cultivated as free-floating neural aggregates which are known to form a developmental niche comprising different types of neural cells, including neural precursor cells (NPCs, progenitor cells and even further matured cells. This niche provides by itself a variety of different growth factors and extracellular matrix proteins that influence the proliferation and differentiation of neural precursor and progenitor cells. The second population was cultivated adherently in monolayer cultures to control most stringently the extracellular environment. This population comprises highly homogeneous NPCs which are supposed to represent an attractive way to provide well-defined neuronal progeny. However, the ability of these different ES cell-derived immature neural cell populations to generate functional neuronal networks has not been assessed so far. Results While both precursor populations were shown to differentiate into sufficient quantities of mature NeuN+ neurons that also express GABA or vesicular-glutamate-transporter-2 (vGlut2, only aggregate-derived neuronal populations exhibited a synchronously oscillating network activity 2–4 weeks after initiating the differentiation as detected by the microelectrode array technology. Neurons derived from homogeneous NPCs within monolayer cultures did merely show uncorrelated spiking activity even when differentiated for up to 12 weeks. We demonstrated that these neurons exhibited sparsely ramified neurites and an embryonic vGlut2 distribution suggesting an inhibited terminal neuronal maturation. In comparison, neurons derived from heterogeneous populations within neural aggregates appeared as fully mature with a dense neurite network and punctuated

  6. In vitro expansion of the mammary stem/progenitor cell population by xanthosine treatment

    Directory of Open Access Journals (Sweden)

    Choudhary Ratan K

    2012-06-01

    Full Text Available Abstract Background Mammary stem cells are critical for growth and maintenance of the mammary gland and therefore are of considerable interest for improving productivity and efficiency of dairy animals. Xanthosine treatment has been demonstrated to promote expansion of putative mammary stem cells in vivo, and hepatic and hair follicle stem cells in vitro. In the latter, xanthosine promoted the symmetrical division of hepatic and hair follicle stem cells. The objective of this study was to determine if treating primary cultures of bovine mammary epithelial cells (MEC with xanthosine increases the stem/progenitor cell population by promoting symmetrical division of mammary stem cells. Results In vitro treatment with xanthosine increased the population of MEC during the exponential phase of cell growth, reducing the doubling time from 86 h in control cultures to 60 h in xanthosine-treated cultures. The bromodeoxyuridine (BrdU labeling index and the proportion of MEC in S-phase both were increased by xanthosine treatment, indicating that increased cell accretion was due to increased cell proliferation. Analysis of daughter-pairs indicated that xanthosine promoted a shift from asymmetric to symmetric cell division. Moreover, the 30 % increase in symmetric cell division was concomitant with an increase in the proportion of MEC that were positive for a putative stem cell marker (FNDC3B and a trend toward increased telomerase activity. These results suggest that xanthosine treatment in vitro can increase cell proliferation, promote symmetric cell division and enhance stem/progenitor cell activity. Conclusions Xanthosine treatment increased the proliferation rate of bovine MEC in vitro. This was likely to be mediated by an increase in the proportion of stem/progenitor cells in the MEC population due to promotion of symmetrical stem cell division by xanthosine.

  7. Microfluidic isolation of cancer-cell-derived microvesicles from hetergeneous extracellular shed vesicle populations.

    Science.gov (United States)

    Santana, Steven M; Antonyak, Marc A; Cerione, Richard A; Kirby, Brian J

    2014-12-01

    Extracellular shed vesicles, including exosomes and microvesicles, are disseminated throughout the body and represent an important conduit of cell communication. Cancer-cell-derived microvesicles have potential as a cancer biomarker as they help shape the tumor microenvironment to promote the growth of the primary tumor and prime the metastatic niche. It is likely that, in cancer cell cultures, the two constituent extracellular shed vesicle subpopulations, observed in dynamic light scattering, represent an exosome population and a cancer-cell-specific microvesicle population and that extracellular shed vesicle size provides information about provenance and cargo. We have designed and implemented a novel microfluidic technology that separates microvesicles, as a function of diameter, from heterogeneous populations of cancer-cell-derived extracellular shed vesicles. We measured cargo carried by the microvesicle subpopulation processed through this microfluidic platform. Such analyses could enable future investigations to more accurately and reliably determine provenance, functional activity, and mechanisms of transformation in cancer. PMID:25342569

  8. Identification of a population of cells with hematopoietic stem cell properties in mouse aorta-gonad-mesonephros cultures

    International Nuclear Information System (INIS)

    The aorta-gonad-mesonephros (AGM) region is a primary source of definitive hematopoietic cells in the midgestation mouse embryo. In cultures of dispersed AGM regions, adherent cells containing endothelial cells are observed first, and then non-adherent hematopoietic cells are produced. Here we report on the characterization of hematopoietic cells that emerge in the AGM culture. Based on the expression profiles of CD45 and c-Kit, we defined three cell populations: CD45low c-Kit+ cells that had the ability to form hematopoietic cell colonies in methylcellulose media and in co-cultures with stromal cells; CD45low c-Kit- cells that showed a granulocyte morphology; CD45high c-Kitlow/- that exhibited a macrophage morphology. In co-cultures of OP9 stromal cells and freshly prepared AGM cultures, CD45low c-Kit+ cells from the AGM culture had the abilities to reproduce CD45low c-Kit+ cells and differentiate into CD45low c-Kit- and CD45high c-Kitlow/- cells, whereas CD45low c-Kit- and CD45high c-Kitlow/- did not produce CD45low c-Kit+ cells. Furthermore, CD45low c-Kit+ cells displayed a long-term repopulating activity in adult hematopoietic tissue when transplanted into the liver of irradiated newborn mice. These results indicate that CD45low c-Kit+ cells from the AGM culture have the potential to reconstitute multi-lineage hematopoietic cells

  9. Characterization of bone cells isolated on discontinuous Percoll gradients: distribution in sequentially derived populations.

    Science.gov (United States)

    Wong, G L; Ng, M C; Calabrese, D W; Swartzendruber, D E

    1991-09-01

    Bone cell populations obtained by sequential digestion of newborn mouse calvariae remain morphologically heterogeneous despite well-documented biochemical differences. Fractionation of these populations on Percoll gradient reveal three major cell groups of low, intermediate, and high buoyant density (1.056, 1.070, and 1.095 g/ml) that are present in different ratios in early and late released populations. Cells of low and intermediate density dominate in early released populations. In contrast, late released populations contain mostly high-density cells. Basal levels of alkaline phosphatase are highest in cells of intermediate buoyant density. All cells respond to PTH with cAMP production and morphologic transformation, but biochemical responses to PTH, such as secretion of insulin-like growth factor I (IGF-I) and stimulation of alkaline phosphatase activity, occur mostly in cells of intermediate density. These data suggest that (1) subclasses of osteoblasts can be further separated by density and (2) PTH effects on alkaline phosphatase activity and IGF-I secretion are probably expressed by osteoblasts of a certain subclass and/or stage of development. PMID:1665004

  10. 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...

  11. Proteomics analysis reveals a Th17-prone cell population in presymptomatic graft-versus-host disease

    Science.gov (United States)

    Li, Wei; Liu, Liangyi; Gomez, Aurelie; Zhang, Jilu; Ramadan, Abdulraouf; Zhang, Qing; Choi, Sung W.; Zhang, Peng; Greenson, Joel K.; Liu, Chen; Jiang, Di; Virts, Elizabeth; Kelich, Stephanie L.; Chu, Hong Wei; Flynn, Ryan; Blazar, Bruce R.; Hanenberg, Helmut; Hanash, Samir; Paczesny, Sophie

    2016-01-01

    Gastrointestinal graft-versus-host-disease (GI-GVHD) is a life-threatening complication occurring after allogeneic hematopoietic cell transplantation (HCT), and a blood biomarker that permits stratification of HCT patients according to their risk of developing GI-GVHD would greatly aid treatment planning. Through in-depth, large-scale proteomic profiling of presymptomatic samples, we identified a T cell population expressing both CD146, a cell adhesion molecule, and CCR5, a chemokine receptor that is upregulated as early as 14 days after transplantation in patients who develop GI-GVHD. The CD4+CD146+CCR5+ T cell population is Th17 prone and increased by ICOS stimulation. shRNA knockdown of CD146 in T cells reduced their transmigration through endothelial cells, and maraviroc, a CCR5 inhibitor, reduced chemotaxis of the CD4+CD146+CCR5+ T cell population toward CCL14. Mice that received CD146 shRNA–transduced human T cells did not lose weight, showed better survival, and had fewer CD4+CD146+CCR5+ T cells and less pathogenic Th17 infiltration in the intestine, even compared with mice receiving maraviroc with control shRNA– transduced human T cells. Furthermore, the frequency of CD4+CD146+CCR5+ Tregs was increased in GI-GVHD patients, and these cells showed increased plasticity toward Th17 upon ICOS stimulation. Our findings can be applied to early risk stratification, as well as specific preventative therapeutic strategies following HCT. PMID:27195312

  12. Delay of cell cycle progression after X-irradiation of synchronized populations of human cells (NHIK 3025) in culture

    International Nuclear Information System (INIS)

    The effect of X-irradiation on the cell cycle progression of synchronized populations of the human cell line NHIK 3035 has been studied in terms of the radiation-induced delay of DNA replication and cell division. Results were obtained by flow cytometric measurements of histograms of cellular DNA content and parallel use of conventional methods for cell cycle analysis, such as pulse labelling with (3H) thymidine and counting of cell numbers. The two sets of methods were generally in good agreement, but the advantages of employing two independent techniques are pointed out. Irradiation was found to have a minor influence on DNA replication. As compared with unirradiated populations, half-completed DNA replication was 20-30 min delayed in populations given 580 rad in mid-G1 or 290 rad in early S. Cell cycle progression was markedly delayed in G2. The sensitivity induction of this delay was 0.6 min/rad for populations irradiated in mid-G1, and 1.4 min/rad for populations irradiated in early S. (author)

  13. Mitochondrial DNA deletion mutations in adult mouse cardiac side population cells

    Energy Technology Data Exchange (ETDEWEB)

    Lushaj, Entela B., E-mail: lushaj@surgery.wisc.edu [Division of Cardiothoracic Surgery, Department of Surgery, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53792 (United States); Lozonschi, Lucian; Barnes, Maria; Anstadt, Emily; Kohmoto, Takushi [Division of Cardiothoracic Surgery, Department of Surgery, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53792 (United States)

    2012-06-01

    We investigated the presence and potential role of mitochondrial DNA (mtDNA) deletion mutations in adult cardiac stem cells. Cardiac side population (SP) cells were isolated from 12-week-old mice. Standard polymerase chain reaction (PCR) was used to screen for the presence of mtDNA deletion mutations in (a) freshly isolated SP cells and (b) SP cells cultured to passage 10. When present, the abundance of mtDNA deletion mutation was analyzed in single cell colonies. The effect of different levels of deletion mutations on SP cell growth and differentiation was determined. MtDNA deletion mutations were found in both freshly isolated and cultured cells from 12-week-old mice. While there was no significant difference in the number of single cell colonies with mtDNA deletion mutations from any of the groups mentioned above, the abundance of mtDNA deletion mutations was significantly higher in the cultured cells, as determined by quantitative PCR. Within a single clonal cell population, the detectable mtDNA deletion mutations were the same in all cells and unique when compared to deletions of other colonies. We also found that cells harboring high levels of mtDNA deletion mutations (i.e. where deleted mtDNA comprised more than 60% of total mtDNA) had slower proliferation rates and decreased differentiation capacities. Screening cultured adult stem cells for mtDNA deletion mutations as a routine assessment will benefit the biomedical application of adult stem cells.

  14. Evaluation of suppressive and pro-resolving effects of EPA and DHA in human primary monocytes and T-helper cells[S

    OpenAIRE

    Jaudszus, Anke; Gruen, Michael; Watzl, Bernhard; Ness, Christina; Roth, Alexander; Lochner, Alfred; Barz, Dagmar; Gabriel, Holger; Rothe, Michael; Jahreis, Gerhard

    2013-01-01

    Despite their beneficial anti-inflammatory properties, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) may increase the infection risk at high doses, likely by generating an immune-depressed state. To assess the contribution of different immune cell populations to the immunomodulatory fatty acid effect, we comparatively investigated several aspects of inflammation in human T-helper (Th) cells and monocytes. Both fatty acids, but DHA to a lesser extent compared with EPA, selectively...

  15. An examination of population exposure to traffic related air pollution: Comparing spatially and temporally resolved estimates against long-term average exposures at the home location.

    Science.gov (United States)

    Shekarrizfard, Maryam; Faghih-Imani, Ahmadreza; Hatzopoulou, Marianne

    2016-05-01

    Air pollution in metropolitan areas is mainly caused by traffic emissions. This study presents the development of a model chain consisting of a transportation model, an emissions model, and atmospheric dispersion model, applied to dynamically evaluate individuals' exposure to air pollution by intersecting daily trajectories of individuals and hourly spatial variations of air pollution across the study domain. This dynamic approach is implemented in Montreal, Canada to highlight the advantages of the method for exposure analysis. The results for nitrogen dioxide (NO2), a marker of traffic related air pollution, reveal significant differences when relying on spatially and temporally resolved concentrations combined with individuals' daily trajectories compared to a long-term average NO2 concentration at the home location. We observe that NO2 exposures based on trips and activity locations visited throughout the day were often more elevated than daily NO2 concentrations at the home location. The percentage of all individuals with a lower 24-hour daily average at home compared to their 24-hour mobility exposure is 89.6%, of which 31% of individuals increase their exposure by more than 10% by leaving the home. On average, individuals increased their exposure by 23-44% while commuting and conducting activities out of home (compared to the daily concentration at home), regardless of air quality at their home location. We conclude that our proposed dynamic modelling approach significantly improves the results of traditional methods that rely on a long-term average concentration at the home location and we shed light on the importance of using individual daily trajectories to understand exposure. PMID:26970897

  16. The epidermis comprises autonomous compartments maintained by distinct stem cell populations

    DEFF Research Database (Denmark)

    Page, Mahalia E; Lombard, Patrick; Ng, Felicia;

    2013-01-01

    populations. In contrast, upon wounding, stem cell progeny from multiple compartments acquire lineage plasticity and make permanent contributions to regenerating tissue. We further show that oncogene activation in Lrig1(+ve) cells drives hyperplasia but requires auxiliary stimuli for tumor formation...

  17. An imbalance in progenitor cell populations reflects tumour progression in breast cancer primary culture models.

    LENUS (Irish Health Repository)

    Donatello, Simona

    2011-01-01

    Many factors influence breast cancer progression, including the ability of progenitor cells to sustain or increase net tumour cell numbers. Our aim was to define whether alterations in putative progenitor populations could predict clinicopathological factors of prognostic importance for cancer progression.

  18. Loss mechanisms in organic solar cells based on perylene diimide acceptors studied by time-resolved photoluminescence

    Science.gov (United States)

    Gerhard, Marina; Gehrig, Dominik; Howard, Ian A.; Arndt, Andreas P.; Bilal, Mühenad; Rahimi-Iman, Arash; Lemmer, Uli; Laquai, Frédéric; Koch, Martin

    2016-04-01

    In organic photovoltaics (OPV), perylene diimide (PDI) acceptor materials are promising candidates to replace the commonly used, but more expensive fullerene derivatives. The use of alternative acceptor materials however implies new design guidelines for OPV devices. It is therefore important to understand the underlying photophysical processes, which either lead to charge generation or geminate recombination. In this contribution, we investigate radiative losses in a series of OPV materials based on two polymers, P3HT and PTB7, respectively, which were blended with different PDI derivatives. Our time-resolved photoluminescence measurements (TRPL) allow us to identify different loss mechanisms by the decay characteristics of several excitonic species. In particular, we find evidence for unfavorable morphologies in terms of large-scale pure domains, inhibited exciton transport and incomplete charge transfer. Furthermore, in one of the P3HT-blends, an interfacial emissive charge transfer (CT) state with strong trapping character is identified.

  19. Predators inhibit brain cell proliferation in natural populations of electric fish, Brachyhypopomus occidentalis.

    Science.gov (United States)

    Dunlap, Kent D; Tran, Alex; Ragazzi, Michael A; Krahe, Rüdiger; Salazar, Vielka L

    2016-02-10

    Compared with laboratory environments, complex natural environments promote brain cell proliferation and neurogenesis. Predators are one important feature of many natural environments, but, in the laboratory, predatory stimuli tend to inhibit brain cell proliferation. Often, laboratory predatory stimuli also elevate plasma glucocorticoids, which can then reduce brain cell proliferation. However, it is unknown how natural predators affect cell proliferation or whether glucocorticoids mediate the neurogenic response to natural predators. We examined brain cell proliferation in six populations of the electric fish, Brachyhypopomus occidentalis, exposed to three forms of predator stimuli: (i) natural variation in the density of predatory catfish; (ii) tail injury, presumably from predation attempts; and (iii) the acute stress of capture. Populations with higher predation pressure had lower density of proliferating (PCNA+) cells, and fish with injured tails had lower proliferating cell density than those with intact tails. However, plasma cortisol did not vary at the population level according to predation pressure or at the individual level according to tail injury. Capture stress significantly increased cortisol, but only marginally decreased cell proliferation. Thus, it appears that the presence of natural predators inhibits brain cell proliferation, but not via mechanisms that depend on changes in basal cortisol levels. This study is the first demonstration of predator-induced alteration of brain cell proliferation in a free-living vertebrate. PMID:26842566

  20. Optimized Stem Cell Detection Using the DyeCycle-Triggered Side Population Phenotype

    Science.gov (United States)

    Boesch, Maximilian; Wolf, Dominik; Sopper, Sieghart

    2016-01-01

    Tissue and cancer stem cells are highly attractive target populations for regenerative medicine and novel potentially curative anticancer therapeutics. In order to get a better understanding of stem cell biology and function, it is essential to reproducibly identify these stem cells from biological samples for subsequent characterization or isolation. ABC drug transporter expression is a hallmark of stem cells. This is utilized to identify (cancer) stem cells by exploiting their dye extrusion properties, which is referred to as the “side population assay.” Initially described for high-end flow cytometers equipped with ultraviolet lasers, this technique is now also amenable for a broader scientific community, owing to the increasing availability of violet laser-furnished cytometers and the advent of DyeCycle Violet (DCV). Here, we describe important technical aspects of the DCV-based side population assay and discuss potential pitfalls and caveats helping scientists to establish a valid and reproducible DCV-based side population assay. In addition, we investigate the suitability of blue laser-excitable DyeCycle dyes for side population detection. This knowledge will help to improve and standardize detection and isolation of stem cells based on their expression of ABC drug transporters. PMID:26798352

  1. Noise and Epigenetic Inheritance of Single-Cell Division Times Influence Population Fitness.

    Science.gov (United States)

    Cerulus, Bram; New, Aaron M; Pougach, Ksenia; Verstrepen, Kevin J

    2016-05-01

    The fitness effect of biological noise remains unclear. For example, even within clonal microbial populations, individual cells grow at different speeds. Although it is known that the individuals' mean growth speed can affect population-level fitness, it is unclear how or whether growth speed heterogeneity itself is subject to natural selection. Here, we show that noisy single-cell division times can significantly affect population-level growth rate. Using time-lapse microscopy to measure the division times of thousands of individual S. cerevisiae cells across different genetic and environmental backgrounds, we find that the length of individual cells' division times can vary substantially between clonal individuals and that sublineages often show epigenetic inheritance of division times. By combining these experimental measurements with mathematical modeling, we find that, for a given mean division time, increasing heterogeneity and epigenetic inheritance of division times increases the population growth rate. Furthermore, we demonstrate that the heterogeneity and epigenetic inheritance of single-cell division times can be linked with variation in the expression of catabolic genes. Taken together, our results reveal how a change in noisy single-cell behaviors can directly influence fitness through dynamics that operate independently of effects caused by changes to the mean. These results not only allow a better understanding of microbial fitness but also help to more accurately predict fitness in other clonal populations, such as tumors. PMID:27068419

  2. Morphokinetics of mesenterial lymphatic node cell populations at exposure of gold nanoparticles in experiment

    Directory of Open Access Journals (Sweden)

    O.V. Zlobina

    2012-12-01

    Full Text Available The influence of gold nanoparticles with different size (1-3 nm, 15 nm and 50 nm on the morphokinetics of mesenterial lymphatic node cell populations of healthy laboratory animals was investigated. It was established that the oral administration of gold nanoparticles caused the changes of morphokinetics of mesenterial lymphatic node cell populations. The morphological reorganizations in the mesenterial lymphatic nodes testified about activation of migration processes, the proliferation and differentiation processes of immunocompetent cells, which assumes the presence of immunomodulating action of gold nanoparticles.

  3. Evidence of distinct tumour-propagating cell populations with different properties in primary human hepatocellular carcinoma.

    Directory of Open Access Journals (Sweden)

    Federico Colombo

    Full Text Available BACKGROUND AND AIMS: Increasing evidence that a number of malignancies are characterised by tumour cell heterogeneity has recently been published, but there is still a lack of data concerning liver cancers. The aim of this study was to investigate and characterise tumour-propagating cell (TPC compartments within human hepatocellular carcinoma (HCC. METHODS: After long-term culture, we identified three morphologically different tumour cell populations in a single HCC specimen, and extensively characterised them by means of flow cytometry, fluorescence microscopy, karyotyping and microarray analyses, single cell cloning, and xenotransplantation in NOD/SCID/IL2Rγ/⁻ mice. RESULTS: The primary cell populations (hcc-1, -2 and -3 and two clones generated by means of limiting dilutions from hcc-1 (clone-1/7 and -1/8 differently expressed a number of tumour-associated stem cell markers, including EpCAM, CD49f, CD44, CD133, CD56, Thy-1, ALDH and CK19, and also showed different doubling times, drug resistance and tumorigenic potential. Moreover, we found that ALDH expression, in combination with CD44 or Thy-1 negativity or CD56 positivity identified subpopulations with a higher clonogenic potential within hcc-1, hcc-2 and hcc-3 primary cell populations, respectively. Karyotyping revealed the clonal evolution of the cell populations and clones within the primary tumour. Importantly, the primary tumour cell population with the greatest tumorigenic potential and drug resistance showed more chromosomal alterations than the others and contained clones with epithelial and mesenchymal features. CONCLUSIONS: Individual HCCs can harbor different self-renewing tumorigenic cell types expressing a variety of morphological and phenotypical markers, karyotypic evolution and different gene expression profiles. This suggests that the models of hepatic carcinogenesis should take into account TPC heterogeneity due to intratumour clonal evolution.

  4. Resolving protein interactions and organization downstream the T cell antigen receptor using single-molecule localization microscopy: a review

    Science.gov (United States)

    Sherman, Eilon

    2016-06-01

    Signal transduction is mediated by heterogeneous and dynamic protein complexes. Such complexes play a critical role in diverse cell functions, with the important example of T cell activation. Biochemical studies of signalling complexes and their imaging by diffraction limited microscopy have resulted in an intricate network of interactions downstream the T cell antigen receptor (TCR). However, in spite of their crucial roles in T cell activation, much remains to be learned about these signalling complexes, including their heterogeneous contents and size distribution, their complex arrangements in the PM, and the molecular requirements for their formation. Here, we review how recent advancements in single molecule localization microscopy have helped to shed new light on the organization of signalling complexes in single molecule detail in intact T cells. From these studies emerges a picture where cells extensively employ hierarchical and dynamic patterns of nano-scale organization to control the local concentration of interacting molecular species. These patterns are suggested to play a critical role in cell decision making. The combination of SMLM with more traditional techniques is expected to continue and critically contribute to our understanding of multimolecular protein complexes and their significance to cell function.

  5. Bone marrow-derived cells in the population of spinal microglia after peripheral nerve injury

    OpenAIRE

    Ryoichi Tashima; Satsuki Mikuriya; Daisuke Tomiyama; Miho Shiratori-Hayashi; Tomohiro Yamashita; Yuta Kohro; Hidetoshi Tozaki-Saitoh; Kazuhide Inoue; Makoto Tsuda

    2016-01-01

    Accumulating evidence indicates that peripheral nerve injury (PNI) activates spinal microglia that are necessary for neuropathic pain. Recent studies using bone marrow (BM) chimeric mice have reported that after PNI, circulating BM-derived cells infiltrate into the spinal cord and differentiate into microglia-like cells. This raises the possibility that the population of spinal microglia after PNI may be heterogeneous. However, the infiltration of BM cells in the spinal cord remains controver...

  6. Repeated cisplatin treatment can lead to a multiresistant tumor cell population with stem cell features and sensitivity to 3-bromopyruvate.

    Science.gov (United States)

    Wintzell, My; Löfstedt, Lina; Johansson, Joel; Pedersen, Anne B; Fuxe, Jonas; Shoshan, Maria

    2012-12-01

    Cisplatin is used in treatment of several types of cancer, including epithelial ovarian carcinoma (EOC). In order to mimic clinical treatment and to investigate longterm effects of cisplatin in surviving cancer cells, two EOC cell lines were repeatedly treated with low doses. In the SKOV-3 cell line originating from malignant ascites, but not in A2780 cells from a primary tumor, this led to emergence of a stable population (SKOV-3-R) which in the absence of cisplatin showed increased motility, epithelial-mesenchymal transition (EMT) and expression of cancer stem cell markers CD117, CD44 and ALDH1. Accordingly, the cells formed self-renewing spheres in serum-free stem cell medium. Despite upregulation of mitochondrial mass and cytochrome c, and no upregulation of Bcl-2/Bcl-xL, SKOV-3-R were multiresistant to antineoplastic drugs. Cancer stem cells, or tumor-initiating cells (TICs) are highly chemoresistant and are believed to cause relapse into disseminated and resistant EOC. Our second aim was therefore to target resistance in these TIC-like cells. Resistance could be correlated with upregulation of hexokinase-II and VDAC, which are known to form a survival-promoting mitochondrial complex. The cells were thus sensitive to 3-bromopyruvate, which dissociates hexokinase-II from this complex, and were particularly sensitive to combination treatment with cisplatin at doses down to 0.1 x IC 50. 3-bromopyruvate might thus be of use in targeting the especially aggressive TIC populations. PMID:22954696

  7. 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.

  8. Changes in the population of perivascular cells in the bone tissue remodeling zones under microgravity

    Science.gov (United States)

    Katkova, Olena; Rodionova, Natalia; Shevel, Ivan

    2016-07-01

    Microgravity and long-term hypokinesia induce reduction both in bone mass and mineral saturation, which can lead to the development of osteoporosis and osteopenia. (Oganov, 2003). Reorganizations and adaptive remodeling processes in the skeleton bones occur in the topographical interconnection with blood capillaries and perivascular cells. Radioautographic studies with 3H- thymidine (Kimmel, Fee, 1980; Rodionova, 1989, 2006) have shown that in osteogenesis zones there is sequential differentiation process of the perivascular cells into osteogenic. Hence the study of populations of perivascular stromal cells in areas of destructive changes is actual. Perivascular cells from metaphysis of the rat femoral bones under conditions of modeling microgravity were studied using electron microscopy and cytochemistry (hindlimb unloading, 28 days duration) and biosatellite «Bion-M1» (duration of flight from April 19 till May 19, 2013 on C57, black mice). It was revealed that both control and test groups populations of the perivascular cells are not homogeneous in remodeling adaptive zones. These populations comprise of adjacent to endothelium poorly differentiated forms and isolated cells with signs of differentiation (specific increased volume of rough endoplasmic reticulum in cytoplasm). Majority of the perivascular cells in the control group (modeling microgravity) reveals reaction to alkaline phosphatase (marker of the osteogenic differentiation). In poorly differentiated cells this reaction is registered in nucleolus, nucleous and cytoplasm. In differentiating cells activity of the alkaline phosphatase is also detected on the outer surface of the cellular membrane. Unlike the control group in the bones of experimental animals reaction to the alkaline phosphatase is registered not in all cells of perivascular population. Part of the differentiating perivascular cells does not contain a product of the reaction. Under microgravity some poorly differentiated perivascular

  9. The evolution of carrying capacity in constrained and expanding tumour cell populations

    Science.gov (United States)

    Gerlee, Philip; Anderson, Alexander R. A.

    2015-10-01

    Cancer cells are known to modify their micro-environment such that it can sustain a larger population, or, in ecological terms, they construct a niche which increases the carrying capacity of the population. It has however been argued that niche construction, which benefits all cells in the tumour, would be selected against since cheaters could reap the benefits without paying the cost. We have investigated the impact of niche specificity on tumour evolution using an individual based model of breast tumour growth, in which the carrying capacity of each cell consists of two components: an intrinsic, subclone-specific part and a contribution from all neighbouring cells. Analysis of the model shows that the ability of a mutant to invade a resident population depends strongly on the specificity. When specificity is low selection is mostly on growth rate, while high specificity shifts selection towards increased carrying capacity. Further, we show that the long-term evolution of the system can be predicted using adaptive dynamics. By comparing the results from a spatially structured versus well-mixed population we show that spatial structure restores selection for carrying capacity even at zero specificity, which poses a solution to the niche construction dilemma. Lastly, we show that an expanding population exhibits spatially variable selection pressure, where cells at the leading edge exhibit higher growth rate and lower carrying capacity than those at the centre of the tumour.

  10. Attenuated Toxoplasma gondii Stimulates Immunity to Pancreatic Cancer by Manipulation of Myeloid Cell Populations.

    Science.gov (United States)

    Sanders, Kiah L; Fox, Barbara A; Bzik, David J

    2015-08-01

    Suppressive myeloid cells represent a significant barrier to the generation of productive antitumor immune responses to many solid tumors. Eliminating or reprogramming suppressive myeloid cells to abrogate tumor-associated immune suppression is a promising therapeutic approach. We asked whether treatment of established aggressive disseminated pancreatic cancer with the immunotherapeutic attenuated Toxoplasma gondii vaccine strain CPS would trigger tumor-associated myeloid cells to generate therapeutic antitumor immune responses. CPS treatment significantly decreased tumor-associated macrophages and markedly increased dendritic cell infiltration of the pancreatic tumor microenvironment. Tumor-resident macrophages and dendritic cells, particularly cells actively invaded by CPS, increased expression of costimulatory molecules CD80 and CD86 and concomitantly boosted their production of IL12. CPS treatment increased CD4(+) and CD8(+) T-cell infiltration into the tumor microenvironment, activated tumor-resident T cells, and increased IFNγ production by T-cell populations. CPS treatment provided a significant therapeutic benefit in pancreatic tumor-bearing mice. This therapeutic benefit depended on IL12 and IFNγ production, MyD88 signaling, and CD8(+) T-cell populations. Although CD4(+) T cells exhibited activated effector phenotypes and produced IFNγ, CD4(+) T cells as well as natural killer cells were not required for the therapeutic benefit. In addition, CD8(+) T cells isolated from CPS-treated tumor-bearing mice produced IFNγ after re-exposure to pancreatic tumor antigen, suggesting this immunotherapeutic treatment stimulated tumor cell antigen-specific CD8(+) T-cell responses. This work highlights the potency and immunotherapeutic efficacy of CPS treatment and demonstrates the significance of targeting tumor-associated myeloid cells as a mechanism to stimulate more effective immunity to pancreatic cancer. PMID:25804437

  11. Functional and phenotypic differences of pure populations of stem cell-derived astrocytes and neuronal precursor cells.

    Science.gov (United States)

    Kleiderman, Susanne; Sá, João V; Teixeira, Ana P; Brito, Catarina; Gutbier, Simon; Evje, Lars G; Hadera, Mussie G; Glaab, Enrico; Henry, Margit; Sachinidis, Agapios; Alves, Paula M; Sonnewald, Ursula; Leist, Marcel

    2016-05-01

    Availability of homogeneous astrocyte populations would facilitate research concerning cell plasticity (metabolic and transcriptional adaptations; innate immune responses) and cell cycle reactivation. Current protocols to prepare astrocyte cultures differ in their final content of immature precursor cells, preactivated cells or entirely different cell types. A new method taking care of all these issues would improve research on astrocyte functions. We found here that the exposure of a defined population of pluripotent stem cell-derived neural stem cells (NSC) to BMP4 results in pure, nonproliferating astrocyte cultures within 24-48 h. These murine astrocytes generated from embryonic stem cells (mAGES) expressed the positive markers GFAP, aquaporin 4 and GLT-1, supported neuronal function, and acquired innate immune functions such as the response to tumor necrosis factor and interleukin 1. The protocol was applicable to several normal or disease-prone pluripotent cell lines, and the corresponding mAGES all exited the cell cycle and lost most of their nestin expression, in contrast to astrocytes generated by serum-addition or obtained as primary cultures. Comparative gene expression analysis of mAGES and NSC allowed quantification of differences between the two cell types and a definition of an improved marker set to define astrocytes. Inclusion of several published data sets in this transcriptome comparison revealed the similarity of mAGES with cortical astrocytes in vivo. Metabolic analysis of homogeneous NSC and astrocyte populations revealed distinct neurochemical features: both cell types synthesized glutamine and citrate, but only mature astrocytes released these metabolites. Thus, the homogeneous cultures allowed an improved definition of NSC and astrocyte features. PMID:26689134

  12. Loss mechanisms in organic solar cells based on perylene diimide acceptors studied by time-resolved photoluminescence

    KAUST Repository

    Gerhard, Marina

    2016-04-27

    In organic photovoltaics (OPV), perylene diimide (PDI) acceptor materials are promising candidates to replace the commonly used, but more expensive fullerene derivatives. The use of alternative acceptor materials however implies new design guidelines for OPV devices. It is therefore important to understand the underlying photophysical processes, which either lead to charge generation or geminate recombination. In this contribution, we investigate radiative losses in a series of OPV materials based on two polymers, P3HT and PTB7, respectively, which were blended with different PDI derivatives. Our time-resolved photoluminescence measurements (TRPL) allow us to identify different loss mechanisms by the decay characteristics of several excitonic species. In particular, we find evidence for unfavorable morphologies in terms of large-scale pure domains, inhibited exciton transport and incomplete charge transfer. Furthermore, in one of the P3HT-blends, an interfacial emissive charge transfer (CT) state with strong trapping character is identified. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  13. Study of spatially resolved impurity diffusion in CdTe solar cells using voltage dependent quantum efficiency

    International Nuclear Information System (INIS)

    The performance stability of CdTe/CdS solar cells is strongly determined by diffusion of impurities from the back contact into the absorber layer and hetero-junction. Impurity migration changes the effective carrier concentration and barriers in the device by compensation of donors or acceptors and by creation of defect centres. The CdS window layer is particularly affected by this phenomenon, since the impurities tend to accumulate there. This can be characterised by measuring the voltage dependent, the so called apparent quantum efficiency (AQE) in the blue wavelength region, while the back contact can be analysed by the AQE in the IR. CdTe/CdS cells with different back contact materials have been stressed in different conditions and ambiences. When thermally stressed in presence of oxygen, enhanced AQEs were observed for cells containing Cu, while cells containing Sb showed negligible changes, in the UV range as well as in the IR range. In comparison, vacuum-stressed Cu containing cells showed lower AQEs, but still higher than non-stressed cells. Results of the stressing tests for different materials and in different conditions have been analysed and interpreted using the recently developed model of a modulated barrier in the CdS bulk

  14. Bone marrow-derived cells in the population of spinal microglia after peripheral nerve injury.

    Science.gov (United States)

    Tashima, Ryoichi; Mikuriya, Satsuki; Tomiyama, Daisuke; Shiratori-Hayashi, Miho; Yamashita, Tomohiro; Kohro, Yuta; Tozaki-Saitoh, Hidetoshi; Inoue, Kazuhide; Tsuda, Makoto

    2016-01-01

    Accumulating evidence indicates that peripheral nerve injury (PNI) activates spinal microglia that are necessary for neuropathic pain. Recent studies using bone marrow (BM) chimeric mice have reported that after PNI, circulating BM-derived cells infiltrate into the spinal cord and differentiate into microglia-like cells. This raises the possibility that the population of spinal microglia after PNI may be heterogeneous. However, the infiltration of BM cells in the spinal cord remains controversial because of experimental adverse effects of strong irradiation used for generating BM chimeric mice. In this study, we evaluated the PNI-induced spinal infiltration of BM-derived cells not only by irradiation-induced myeloablation with various conditioning regimens, but also by parabiosis and mice with genetically labelled microglia, models without irradiation and BM transplantation. Results obtained from these independent approaches provide compelling evidence indicating little contribution of circulating BM-derived cells to the population of spinal microglia after PNI. PMID:27005516

  15. Photoreactivation of ultraviolet irradiated non-dividing populations of ICR 2A frog cells

    International Nuclear Information System (INIS)

    Ultraviolet (UV) irradiation of non-dividing populations of ICR 2A frog cells led to their detachment from the surface of the culture dish and eventual lysis. Exposure of the cells to photoreactivating light after UV irradiation prevented cell killing and was accompanied by a loss of endonuclease sensitive sites from DNA. This photoreversal did not take place when the cells were exposed at 40C to photoreactivating light indicating that the reversal was the result of photoenzymatic repair. As the action of photoreactivating enzyme is specific for the repair of pyrimidine dimers in DNA, the results suggest that pyrimidine dimers in DNA are the critical lesions leading to the death of non-dividing populations of UV irradiated cells. (author)

  16. Population dynamics during cell proliferation and neuronogenesis in the developing murine neocortex

    Science.gov (United States)

    Nowakowski, Richard S.; Caviness, Verne S Jr; Takahashi, Takao; Hayes, Nancy L.

    2002-01-01

    During the development of the neocortex, cell proliferation occurs in two specialized zones adjacent to the lateral ventricle. One of these zones, the ventricular zone, produces most of the neurons of the neocortex. The proliferating population that resides in the ventricular zone is a pseudostratified ventricular epithelium (PVE) that looks uniform in routine histological preparations, but is, in fact, an active and dynamically changing population. In the mouse, over the course of a 6-day period, the PVE produces approximately 95% of the neurons of the adult neocortex. During this time, the cell cycle of the PVE population lengthens from about 8 h to over 18 h and the progenitor population passes through a total of 11 cell cycles. This 6-day, 11-cell cycle period comprises the "neuronogenetic interval" (NI). At each passage through the cell cycle, the proportion of daughter cells that exit the cell cycle (Q cells) increases from 0 at the onset of the NI to 1 at the end of the NI. The proportion of daughter cells that re-enter the cell cycle (P cells) changes in a complementary fashion from 1 at the onset of the NI to 0 at the end of the NI. This set of systematic changes in the cell cycle and the output from the proliferative population of the PVE allows a quantitative and mathematical treatment of the expansion of the PVE and the growth of the cortical plate that nicely accounts for the observed expansion and growth of the developing neocortex. In addition, we show that the cells produced during a 2-h window of development during specific cell cycles reside in a specific set of laminae in the adult cortex, but that the distributions of the output from consecutive cell cycles overlap. These dynamic events occur in all areas of the PVE underlying the neocortex, but there is a gradient of maturation that begins in the rostrolateral neocortex near the striatotelencephalic junction and which spreads across the surface of the neocortex over a period of 24-36 h. The

  17. Radiation-induced chromosome aberrations in cell populations from rat tracheal epithelium

    International Nuclear Information System (INIS)

    To determine cells at risk in the respiratory tract for the induction of cancer, it is essential to know not only the dose of toxic agent to the cells but also the sensitivity of each cell type to the agent. The purpose of this study is to define the radiation sensitivity of cells in the airway epithelium of the rat as the first step in determining the cells at risk for cancer induction by radiation. Tracheal epithelial cells were isolated, sorted by flow cytometry, grown in defined medium and exposed to graded doses of X rays. Survival and the frequency of chromosome aberrations were determined in the total cell population, in the sorted secretary and in the sorted basal cells. There was no difference in radiation-induced cytotoxicity of each cell type. The frequency of chromosome aberrations was determined by linear regression analysis and found to be 0.37 ± 0.01 aberrations/cell/Gy for the unsorted cells and 0.26 ± 0.02 for the sorted secretary cells. Because of the low number and cloning efficiency of basal cells, no data on X-ray-induced chromosome aberrations in these cells is available at the present time. There was a linear decrease in the chromatid-type aberration frequency as a function of time after the radiation exposure. The data suggest that, in terms of radiation sensitivity, all three cell populations are very similar. Thus, if there are differences in the response to a toxic agent such as radon, the differences should reflect differences in radiation dose to the cells. (author)

  18. A pure population of lung alveolar epithelial type II cells derived from human embryonic stem cells

    OpenAIRE

    Wang, Dachun; Haviland, David L.; Burns, Alan R.; Zsigmond, Eva; Wetsel, Rick A.

    2007-01-01

    Alveolar epithelial type II (ATII) cells are small, cuboidal cells that constitute ≈60% of the pulmonary alveolar epithelium. These cells are crucial for repair of the injured alveolus by differentiating into alveolar epithelial type I cells. ATII cells derived from human ES (hES) cells are a promising source of cells that could be used therapeutically to treat distal lung diseases. We have developed a reliable transfection and culture procedure, which facilitates, via genetic selection, the ...

  19. Cytotoxic mechanisms of murine lymphokine-activated killer cells: functional and biochemical characterization of homogeneous populations of spleen LAK cells.

    Science.gov (United States)

    Zychlinsky, A; Joag, S; Liu, C C; Young, J D

    1990-04-01

    A highly purified population of murine lymphokine-activated killer (LAK) cells was obtained by selecting plastic-adherent splenocytes after incubation in high doses of recombinant IL-2. The population obtained was shown to be more than 95% positive for the cell marker asialo-GM1, and negative for both Lyt-1 (CD5) and Lyt-2 (CD8). The cells presented typical large granular lymphocyte morphology, and killed NK-susceptible target cells in an exclusively calcium-dependent fashion. A target cell DNA fragmentation activity of LAK cells could be detected even before target cell death. The presence of Hanukkah Factor/granzyme A/serine esterase 1, CTLA-1/granzyme B/serine esterase 2, and pore-forming protein (PFP/perforin) in these LAK cells was demonstrated by Northern blot analysis, suggesting that these markers are not exclusively associated with cytotoxic T lymphocytes. On immunoblots, antibodies specific for a lymphocyte PFP/perforin reacted with a 70-kDa protein of LAK cells. PFP/perforin was localized by immunofluorescence to the cell granules. A 50-kDa protein antigenically related to the macrophage cytokine tumor necrosis factor (TNF) was detected by immunoblotting and localized by immunofluorescence to both the cell granules and the cytosol. No RNA for TNF, however, could be detected using TNF-specific probes, suggesting that LAK cells may contain a cytotoxic factor which is related to, but distinct from, TNF. The work presented here demonstrates that cytotoxic mediators identified in cell lines are also present in primary cell cultures. PMID:1690083

  20. Tumor-Initiating Cells Are Enriched in CD44hi Population in Murine Salivary Gland Tumor

    OpenAIRE

    Shukun Shen; Wenjun Yang; Zhugang Wang; Xia Lei; Liqun Xu; Yang Wang; Lizhen Wang; Lei Huang; Zhiwei Yu; Xinhong Zhang; Jiang Li; Yan Chen; Xiaoping Zhao; Xuelai Yin; Chenping Zhang

    2011-01-01

    Tumor-initiating cells (T-ICs) discovered in various tumors have been widely reported. However, T-IC populations in salivary gland tumors have yet to be elucidated. Using the established Pleomorphic Adenoma Gene-1 (Plag1) transgenic mouse model of a salivary gland tumor, we identified CD44(high) (CD44(hi)) tumor cells, characterized by high levels of CD44 cell surface expression, as the T-ICs for pleomorphic adenomas. These CD44(hi) tumor cells incorporated 5-bromo-2-deoxyuridine (BrdU), at a...

  1. Clonal genotype and population structure inference from single-cell tumor sequencing.

    Science.gov (United States)

    Roth, Andrew; McPherson, Andrew; Laks, Emma; Biele, Justina; Yap, Damian; Wan, Adrian; Smith, Maia A; Nielsen, Cydney B; McAlpine, Jessica N; Aparicio, Samuel; Bouchard-Côté, Alexandre; Shah, Sohrab P

    2016-07-01

    Single-cell DNA sequencing has great potential to reveal the clonal genotypes and population structure of human cancers. However, single-cell data suffer from missing values and biased allelic counts as well as false genotype measurements owing to the sequencing of multiple cells. We describe the Single Cell Genotyper (https://bitbucket.org/aroth85/scg), an open-source software based on a statistical model coupled with a mean-field variational inference method, which can be used to address these problems and robustly infer clonal genotypes. PMID:27183439

  2. Isolated CD39 Expression on CD4+ T Cells Denotes both Regulatory and Memory Populations

    OpenAIRE

    Zhou, Q.; Yan, J.; Putheti, P.; Wu, Y.; X. Sun; Toxavidis, V.; Tigges, J.; Kassam, N.; Enjyoji, K.; Robson, S C; Strom, T. B.; Gao, W.

    2009-01-01

    Foxp3+ regulatory T cells (Tregs) express both ectoenzymes CD39 and CD73, which in tandem hydrolyze pericellular ATP into adenosine, an immunoinhibitory molecule that contributes to Treg suppressive function. Using Foxp3GFP knockin mice, we noted that the mouse CD4+CD39+ T-cell pool contains two roughly equal size Foxp3+ and Foxp3− populations. While Foxp3+CD39+ cells are CD73bright and are the bone fide Tregs, Foxp3−CD39+ cells do not have suppressive activity and are CD44+CD62L−CD25−CD73dim...

  3. Label-free detection of neuronal differentiation in cell populations using high-throughput live-cell imaging of PC12 cells.

    Directory of Open Access Journals (Sweden)

    Sebastian Weber

    Full Text Available Detection of neuronal cell differentiation is essential to study cell fate decisions under various stimuli and/or environmental conditions. Many tools exist that quantify differentiation by neurite length measurements of single cells. However, quantification of differentiation in whole cell populations remains elusive so far. Because such populations can consist of both proliferating and differentiating cells, the task to assess the overall differentiation status is not trivial and requires a high-throughput, fully automated approach to analyze sufficient data for a statistically significant discrimination to determine cell differentiation. We address the problem of detecting differentiation in a mixed population of proliferating and differentiating cells over time by supervised classification. Using nerve growth factor induced differentiation of PC12 cells, we monitor the changes in cell morphology over 6 days by phase-contrast live-cell imaging. For general applicability, the classification procedure starts out with many features to identify those that maximize discrimination of differentiated and undifferentiated cells and to eliminate features sensitive to systematic measurement artifacts. The resulting image analysis determines the optimal post treatment day for training and achieves a near perfect classification of differentiation, which we confirmed in technically and biologically independent as well as differently designed experiments. Our approach allows to monitor neuronal cell populations repeatedly over days without any interference. It requires only an initial calibration and training step and is thereafter capable to discriminate further experiments. In conclusion, this enables long-term, large-scale studies of cell populations with minimized costs and efforts for detecting effects of external manipulation of neuronal cell differentiation.

  4. Morphokinetics of mesenterial lymphatic node cell populations in exposure of gold nanoparticles within experimental work

    Directory of Open Access Journals (Sweden)

    Dykman L.A.

    2011-06-01

    Full Text Available The research goal is to investigate the influence of gold nanoparticles with different size (1-3 nm, 15 nm and 50 nm on the morphokinetics of mesenterial lymphatic node cell populations of healthy laboratory animals. Experiment included 24 white rats. The investigation was conducted in 4 groups of animals. The animals were administered the gold nanoparticles orally for 15 days. It was established that the oral administration of gold nanoparticles caused the changes of morphokinetics of mesenterial lymphatic node cell populations. The morphological alterations in the mesenterial lymphatic nodes assisted in activation of migration processes, the proliferation and differentiation. The immu-nomodulatory action of gold nanoparticles was proved

  5. Effect of stress on NiO reduction in solid oxide fuel cells: A new application of energy-resolved neutron imaging

    DEFF Research Database (Denmark)

    Makowska, Malgorzata; Strobl, Markus; Lauridsen, Erik Mejdal;

    2015-01-01

    Recently, two new phenomena linking stress field and reduction rates in anode-supported solid oxide fuel cells (SOFCs) have been demonstrated, so-called accelerated creep during reduction and reduction rate enhancement and nucleation due to stress (Frandsen et al., 2014). These complex phenomena...... varying conditions such as different temperatures, various times and different values of applied stress, have been measured. Thus, samples with different contents (and gradients) of Ni and NiO phases were investigated. The first Bragg edge transmission neutron measurements applied for the studies of the...... reduction progress in these samples were performed at two neutron beamline facilities (ISIS in the UK, Helmholtz Zentrum Berlin in Germany). The obtained results demonstrate the possibility to image and distinguish NiO and Ni phases within SOFC anode supports by energy-resolved neutron imaging and the...

  6. Further analyses of human kidney cell populations separated on the space shuttle

    Science.gov (United States)

    Stewart, Robin M.; Todd, Paul; Cole, Kenneth D.; Morrison, Dennis R.

    Cultured human embryonic kidney cells were separated into electrophoretic subpopulations in laboratory experiments and in two separation experiments on the STS-8 (Challenger) Space Shuttle flight using the mid-deck Continuous Flow Electrophoretic Separator (CFES). Populations of cells from each fraction were cultured for the lifetime of the cells, and supernatant medium was withdrawn and replaced at 4-day intervals. Withdrawn medium was frozen at -120°C for subsequent analysis. Enzyme assays, antibodies and gel electrophoresis were used as analytical tools for the detection and quantitation of plasminogen activators in these samples. These assays of frozen culture supernatant fluids confirmed the electrophoretic separation of plasminogen-activator producing cells from non-producing cells, the isolation of cells capable of sustained production, and the separation of cells that produce different plasminogen activators from one another.

  7. Approaches for cytogenetic and molecular analyses of small flow-sorted cell populations from childhood leukemia bone marrow samples

    DEFF Research Database (Denmark)

    Obro, Nina Friesgaard; Madsen, Hans Ole; Ryder, Lars Peter; Andersen, Mette Klarskov; Schmiegelow, Kjeld; Marquart, Hanne Vibeke

    defined cell populations with subsequent analyses of leukemia-associated cytogenetic and molecular marker. The approaches described here optimize the use of the same tube of unfixed, antibody-stained BM cells for flow-sorting of small cell populations and subsequent exploratory FISH and PCR-based analyses....

  8. Peripheral Immune Cell Populations Associated with Cognitive Deficits and Negative Symptoms of Treatment-Resistant Schizophrenia.

    Directory of Open Access Journals (Sweden)

    Emilio Fernandez-Egea

    Full Text Available Hypothetically, psychotic disorders could be caused or conditioned by immunological mechanisms. If so, one might expect there to be peripheral immune system phenotypes that are measurable in blood cells as biomarkers of psychotic states.We used multi-parameter flow cytometry of venous blood to quantify and determine the activation state of 73 immune cell subsets for 18 patients with chronic schizophrenia (17 treated with clozapine, and 18 healthy volunteers matched for age, sex, BMI and smoking. We used multivariate methods (partial least squares to reduce dimensionality and define populations of differentially co-expressed cell counts in the cases compared to controls.Schizophrenia cases had increased relative numbers of NK cells, naïve B cells, CXCR5+ memory T cells and classical monocytes; and decreased numbers of dendritic cells (DC, HLA-DR+ regulatory T-cells (Tregs, and CD4+ memory T cells. Likewise, within the patient group, more severe negative and cognitive symptoms were associated with decreased relative numbers of dendritic cells, HLA-DR+ Tregs, and CD4+ memory T cells. Motivated by the importance of central nervous system dopamine signalling for psychosis, we measured dopamine receptor gene expression in separated CD4+ cells. Expression of the dopamine D3 (DRD3 receptor was significantly increased in clozapine-treated schizophrenia and covaried significantly with differentiated T cell classes in the CD4+ lineage.Peripheral immune cell populations and dopaminergic signalling are disrupted in clozapine-treated schizophrenia. Immuno-phenotypes may provide peripherally accessible and mechanistically specific biomarkers of residual cognitive and negative symptoms in this treatment-resistant subgroup of patients.

  9. An Atypical Splenic B Cell Progenitor Population Supports Antibody Production during Plasmodium Infection in Mice.

    Science.gov (United States)

    Ghosh, Debopam; Wikenheiser, Daniel J; Kennedy, Brian; McGovern, Kathryn E; Stuart, Johnasha D; Wilson, Emma H; Stumhofer, Jason S

    2016-09-01

    Hematopoietic stem and progenitor cells (HSPCs) function to replenish the immune cell repertoire under steady-state conditions and in response to inflammation due to infection or stress. Whereas the bone marrow serves as the primary niche for hematopoiesis, extramedullary mobilization and differentiation of HSPCs occur in the spleen during acute Plasmodium infection, a critical step in the host immune response. In this study, we identified an atypical HSPC population in the spleen of C57BL/6 mice, with a lineage(-)Sca-1(+)c-Kit(-) (LSK(-)) phenotype that proliferates in response to infection with nonlethal Plasmodium yoelii 17X. Infection-derived LSK(-) cells upon transfer into naive congenic mice were found to differentiate predominantly into mature follicular B cells. However, when transferred into infection-matched hosts, infection-derived LSK(-) cells gave rise to B cells capable of entering into a germinal center reaction, and they developed into memory B cells and Ab-secreting cells that were capable of producing parasite-specific Abs. Differentiation of LSK(-) cells into B cells in vitro was enhanced in the presence of parasitized RBC lysate, suggesting that LSK(-) cells expand and differentiate in direct response to the parasite. However, the ability of LSK(-) cells to differentiate into B cells was not dependent on MyD88, as myd88(-/-) LSK(-) cell expansion and differentiation remained unaffected after Plasmodium infection. Collectively, these data identify a population of atypical lymphoid progenitors that differentiate into B lymphocytes in the spleen and are capable of contributing to the ongoing humoral immune response against Plasmodium infection. PMID:27448588

  10. Phototheranostics of CD44-positive cell populations in triple negative breast cancer

    Science.gov (United States)

    Jin, Jiefu; Krishnamachary, Balaji; Mironchik, Yelena; Kobayashi, Hisataka; Bhujwalla, Zaver M.

    2016-01-01

    Triple-negative breast cancer (TNBC) is one of the most lethal subtypes of breast cancer that has limited treatment options. Its high rates of recurrence and metastasis have been associated, in part, with a subpopulation of breast cancer stem-like cells that are resistant to conventional therapies. A compendium of markers such as CD44high/CD24low, and increased expression of the ABCG2 transporter and increased aldehyde dehydrogenase (ALDH1), have been associated with these cells. We developed a CD44-targeted monoclonal antibody photosensitizer conjugate for combined fluorescent detection and photoimmunotherapy (PIT) of CD44 expressing cells in TNBC. The CD44-targeted conjugate demonstrated acute cell killing of breast cancer cells with high CD44 expression. This cell death process was dependent upon CD44-specific cell membrane binding combined with near-infrared irradiation. The conjugate selectively accumulated in CD44-positive tumors and caused dramatic tumor shrinkage and efficient elimination of CD44-positive cell populations following irradiation. This novel phototheranostic strategy provides a promising opportunity for the destruction of CD44-positive populations that include cancer stem-like cells, in locally advanced primary and metastatic TNBC. PMID:27302409

  11. Phototheranostics of CD44-positive cell populations in triple negative breast cancer.

    Science.gov (United States)

    Jin, Jiefu; Krishnamachary, Balaji; Mironchik, Yelena; Kobayashi, Hisataka; Bhujwalla, Zaver M

    2016-01-01

    Triple-negative breast cancer (TNBC) is one of the most lethal subtypes of breast cancer that has limited treatment options. Its high rates of recurrence and metastasis have been associated, in part, with a subpopulation of breast cancer stem-like cells that are resistant to conventional therapies. A compendium of markers such as CD44(high)/CD24(low), and increased expression of the ABCG2 transporter and increased aldehyde dehydrogenase (ALDH1), have been associated with these cells. We developed a CD44-targeted monoclonal antibody photosensitizer conjugate for combined fluorescent detection and photoimmunotherapy (PIT) of CD44 expressing cells in TNBC. The CD44-targeted conjugate demonstrated acute cell killing of breast cancer cells with high CD44 expression. This cell death process was dependent upon CD44-specific cell membrane binding combined with near-infrared irradiation. The conjugate selectively accumulated in CD44-positive tumors and caused dramatic tumor shrinkage and efficient elimination of CD44-positive cell populations following irradiation. This novel phototheranostic strategy provides a promising opportunity for the destruction of CD44-positive populations that include cancer stem-like cells, in locally advanced primary and metastatic TNBC. PMID:27302409

  12. Human Mesenchymal Stem Cells Resolve Airway Inflammation, Hyperreactivity, and Histopathology in a Mouse Model of Occupational Asthma

    OpenAIRE

    Martínez-González, Itziar; Cruz, Maria-Jesús; Moreno, Rafael; Morell, Ferran; Muñoz, Xavier; Aran, Josep M.

    2014-01-01

    Occupational asthma (OA) is characterized by allergic airway inflammation and hyperresponsiveness, leading to progressive airway remodeling and a concomitant decline in lung function. The management of OA remains suboptimal in clinical practice. Thus, establishing effective therapies might overcome the natural history of the disease. We evaluated the ability of human adipose-tissue-derived mesenchymal stem cells (hASCs), either unmodified or engineered to secrete the IL-33 decoy receptor sST2...

  13. Resolving Early Signaling Events in T-Cell Activation Leading to IL-2 and FOXP3 Transcription

    Directory of Open Access Journals (Sweden)

    Jeffrey P. Perley

    2014-11-01

    Full Text Available Signal intensity and feedback regulation are known to be major factors in the signaling events stemming from the T-cell receptor (TCR and its various coreceptors, but the exact nature of these relationships remains in question. We present a mathematical model of the complex signaling network involved in T-cell activation with cross-talk between the Erk, calcium, PKC and mTOR signaling pathways. The model parameters are adjusted to fit new and published data on TCR trafficking, Zap70, calcium, Erk and Isignaling. The regulation of the early signaling events by phosphatases, CD45 and SHP1, and the TCR dynamics are critical to determining the behavior of the model. Additional model corroboration is provided through quantitative and qualitative agreement with experimental data collected under different stimulating and knockout conditions. The resulting model is analyzed to investigate how signal intensity and feedback regulation affect TCR- and coreceptor-mediated signal transduction and their downstream transcriptional profiles to predict the outcome for a variety of stimulatory and knockdown experiments. Analysis of the model shows that: (1 SHP1 negative feedback is necessary for preventing hyperactivity in TCR signaling; (2 CD45 is required for TCR signaling, but also partially suppresses it at high expression levels; and (3 elevated FOXP3 and reduced IL-2 signaling, an expression profile often associated with T regulatory cells (Tregs, is observed when the system is subjected to weak TCR and CD28 costimulation or a severe reduction in CD45 activity.

  14. Therapeutic implications of an enriched cancer stem-like cell population in a human osteosarcoma cell line

    Directory of Open Access Journals (Sweden)

    Martins-Neves Sara R

    2012-04-01

    Full Text Available Abstract Background Osteosarcoma is a bone-forming tumor of mesenchymal origin that presents a clinical pattern that is consistent with the cancer stem cell model. Cells with stem-like properties (CSCs have been identified in several tumors and hypothesized as the responsible for the relative resistance to therapy and tumor relapses. In this study, we aimed to identify and characterize CSCs populations in a human osteosarcoma cell line and to explore their role in the responsiveness to conventional therapies. Methods CSCs were isolated from the human MNNG/HOS cell line using the sphere formation assay and characterized in terms of self-renewal, mesenchymal stem cell properties, expression of pluripotency markers and ABC transporters, metabolic activity and tumorigenicity. Cell's sensitivity to conventional chemotherapeutic agents and to irradiation was analyzed and related with cell cycle-induced alterations and apoptosis. Results The isolated CSCs were found to possess self-renewal and multipotential differentiation capabilities, express markers of pluripotent embryonic stem cells Oct4 and Nanog and the ABC transporters P-glycoprotein and BCRP, exhibit low metabolic activity and induce tumors in athymic mice. Compared with parental MNNG/HOS cells, CSCs were relatively more resistant to both chemotherapy and irradiation. None of the treatments have induced significant cell-cycle alterations and apoptosis in CSCs. Conclusions MNNG/HOS osteosarcoma cells contain a stem-like cell population relatively resistant to conventional chemotherapeutic agents and irradiation. This resistant phenotype appears to be related with some stem features, namely the high expression of the drug efflux transporters P-glycoprotein and BCRP and their quiescent nature, which may provide a biological basis for resistance to therapy and recurrence commonly observed in osteosarcoma.

  15. Therapeutic implications of an enriched cancer stem-like cell population in a human osteosarcoma cell line

    International Nuclear Information System (INIS)

    Osteosarcoma is a bone-forming tumor of mesenchymal origin that presents a clinical pattern that is consistent with the cancer stem cell model. Cells with stem-like properties (CSCs) have been identified in several tumors and hypothesized as the responsible for the relative resistance to therapy and tumor relapses. In this study, we aimed to identify and characterize CSCs populations in a human osteosarcoma cell line and to explore their role in the responsiveness to conventional therapies. CSCs were isolated from the human MNNG/HOS cell line using the sphere formation assay and characterized in terms of self-renewal, mesenchymal stem cell properties, expression of pluripotency markers and ABC transporters, metabolic activity and tumorigenicity. Cell's sensitivity to conventional chemotherapeutic agents and to irradiation was analyzed and related with cell cycle-induced alterations and apoptosis. The isolated CSCs were found to possess self-renewal and multipotential differentiation capabilities, express markers of pluripotent embryonic stem cells Oct4 and Nanog and the ABC transporters P-glycoprotein and BCRP, exhibit low metabolic activity and induce tumors in athymic mice. Compared with parental MNNG/HOS cells, CSCs were relatively more resistant to both chemotherapy and irradiation. None of the treatments have induced significant cell-cycle alterations and apoptosis in CSCs. MNNG/HOS osteosarcoma cells contain a stem-like cell population relatively resistant to conventional chemotherapeutic agents and irradiation. This resistant phenotype appears to be related with some stem features, namely the high expression of the drug efflux transporters P-glycoprotein and BCRP and their quiescent nature, which may provide a biological basis for resistance to therapy and recurrence commonly observed in osteosarcoma

  16. Cancer stem cells and cisplatin-resistant cells isolated from non-small-lung cancer cell lines constitute related cell populations

    Science.gov (United States)

    Lopez-Ayllon, Blanca D; Moncho-Amor, Veronica; Abarrategi, Ander; de Cáceres, Inmaculada Ibañez; Castro-Carpeño, Javier; Belda-Iniesta, Cristobal; Perona, Rosario; Sastre, Leandro

    2014-01-01

    Lung cancer is the top cause of cancer-related deceases. One of the reasons is the development of resistance to the chemotherapy treatment. In particular, cancer stem cells (CSCs), can escape treatment and regenerate the bulk of the tumor. In this article, we describe a comparison between cancer cells resistant to cisplatin and CSCs, both derived from the non-small-cell lung cancer cell lines H460 and A549. Cisplatin-resistant cells were obtained after a single treatment with the drug. CSCs were isolated by culture in defined media, under nonadherent conditions. The isolated CSCs were clonogenic, could be differentiated into adherent cells and were less sensitive to cisplatin than the original cells. Cisplatin resistant and CSCs were able to generate primary tumors and to metastasize when injected into immunodeficient Nu/Nu mice, although they formed smaller tumors with a larger latency than untreated cells. Notably, under appropriated proportions, CSCs synergized with differentiated cells to form larger tumors. CSCs also showed increased capacity to induce angiogenesis in Nu/Nu mice. Conversely, H460 cisplatin-resistant cells showed increased tendency to develop bone metastasis. Gene expression analysis showed that several genes involved in tumor development and metastasis (EGR1, COX2, MALAT1, AKAP12, ADM) were similarly induced in CSC and cisplatin-resistant H460 cells, in agreement with a close similarity between these two cell populations. Cells with the characteristic growth properties of CSCs were also isolated from surgical samples of 18 out of 44 lung cancer patients. A significant correlation (P = 0.028) was found between the absence of CSCs and cisplatin sensitivity. PMID:24961511

  17. Identification of a novel population of human cord blood cells with hematopoietic and chondrocytic potential

    Institute of Scientific and Technical Information of China (English)

    Karen E JAY; Anne ROULEAU; T Michael UNDERHILL; Mickie BHATIA

    2004-01-01

    With the exception of mature erythrocytes, cells within the human hematopoietic system are characterized by the cell surface expression of the pan-leukocyte receptor CD45. Here, we identify a novel subset among mononuclear cord blood cells depleted of lineage commitment markers (Lin-) that are devoid of CD45 expression. Surprisingly, functional examination of Lin-CD45- cells also lacking cell surface CD34 revealed they were capable of multipotential hematopoietic progenitor capacity. Co-culture with mouse embryonic limb bud cells demonstrated that Lin-CD45-CD34- cells were capable of contributing to cartilage nodules and differentiating into human chondrocytes. BMP-4, a mesodermal factor known to promote chondrogenesis, significantly augmented Lin-CD45-CD34- differentiation into chondrocytes.Moreover, unlike CD34+ human hematopoietic stem cells, Lin-CD45-CD34- cells were unable to proliferate or survive in liquid cultures, whereas single Lin-CD45-CD34- cells were able to chimerize the inner cell mass (ICM) of murine blastocysts and proliferate in this embryonic environment. Our study identifies a novel population of Lin-CD45-CD34-cells capable of commitment into both hematopoietic and chondrocytic lineages, suggesting that human cord blood may provide a more ubiquitous source of tissue with broader developmental potential than previously appreciated.

  18. A host-parasite model for a two-type cell population

    CERN Document Server

    Alsmeyer, Gerold

    2012-01-01

    A host-parasite model is considered for a population of cells that can be of two types, A or B, and exhibits unilateral reproduction: while a B-cell always splits into two cells of the same type, the two daughter cells of an A-cell can be of any type. The random mechanism that describes how parasites within a cell multiply and are then shared into the daughter cells is allowed to depend on the hosting mother cell as well as its daughter cells. Focusing on the subpopulation of A-cells and its parasites, the model differs from the single-type model recently studied by Bansaye (2008) in that the sharing mechanism may be biased towards one of the two types. Main results are concerned with the nonextinctive case and provide information on the behavior, as $n\\to\\infty$, of the number A-parasites in generation n and the relative proportion of A- and B-cells in this generation which host a given number of parasites. As in (Bansaye,2008), proofs will make use of a so-called random cell line which, when conditioned to ...

  19. Time-resolved quantitative phosphoproteomics

    DEFF Research Database (Denmark)

    Verano-Braga, Thiago; Schwämmle, Veit; Sylvester, Marc;

    2012-01-01

    proteins involved in the Ang-(1-7) signaling, we performed a mass spectrometry-based time-resolved quantitative phosphoproteome study of human aortic endothelial cells (HAEC) treated with Ang-(1-7). We identified 1288 unique phosphosites on 699 different proteins with 99% certainty of correct peptide...

  20. Melanopsin-expressing ganglion cells on macaque and human retinas form two morphologically distinct populations.

    Science.gov (United States)

    Liao, Hsi-Wen; Ren, Xiaozhi; Peterson, Beth B; Marshak, David W; Yau, King-Wai; Gamlin, Paul D; Dacey, Dennis M

    2016-10-01

    The long-term goal of this research is to understand how retinal ganglion cells that express the photopigment melanopsin, also known as OPN4, contribute to vision in humans and other primates. Here we report the results of anatomical studies using our polyclonal antibody specifically against human melanopsin that confirm and extend previous descriptions of melanopsin cells in primates. In macaque and human retina, two distinct populations of melanopsin cells were identified based on dendritic stratification in either the inner or the outer portion of the inner plexiform layer (IPL). Variation in dendritic field size and cell density with eccentricity was confirmed, and dendritic spines, a new feature of melanopsin cells, were described. The spines were the sites of input from DB6 diffuse bipolar cell axon terminals to the inner stratifying type of melanopsin cells. The outer stratifying melanopsin type received inputs from DB6 bipolar cells via a sparse outer axonal arbor. Outer stratifying melanopsin cells also received inputs from axon terminals of dopaminergic amacrine cells. On the outer stratifying melanopsin cells, ribbon synapses from bipolar cells and conventional synapses from amacrine cells were identified in electron microscopic immunolabeling experiments. Both inner and outer stratifying melanopsin cell types were retrogradely labeled following tracer injection in the lateral geniculate nucleus (LGN). In addition, a method for targeting melanopsin cells for intracellular injection using their intrinsic fluorescence was developed. This technique was used to demonstrate that melanopsin cells were tracer coupled to amacrine cells and would be applicable to electrophysiological experiments in the future. J. Comp. Neurol. 524:2845-2872, 2016. © 2016 The Authors The Journal of Comparative Neurology Published by Wiley Periodicals, Inc. PMID:26972791

  1. A polarised population of dynamic microtubules mediates homeostatic length control in animal cells.

    Directory of Open Access Journals (Sweden)

    Remigio Picone

    Full Text Available Because physical form and function are intimately linked, mechanisms that maintain cell shape and size within strict limits are likely to be important for a wide variety of biological processes. However, while intrinsic controls have been found to contribute to the relatively well-defined shape of bacteria and yeast cells, the extent to which individual cells from a multicellular animal control their plastic form remains unclear. Here, using micropatterned lines to limit cell extension to one dimension, we show that cells spread to a characteristic steady-state length that is independent of cell size, pattern width, and cortical actin. Instead, homeostatic length control on lines depends on a population of dynamic microtubules that lead during cell extension, and that are aligned along the long cell axis as the result of interactions of microtubule plus ends with the lateral cell cortex. Similarly, during the development of the zebrafish neural tube, elongated neuroepithelial cells maintain a relatively well-defined length that is independent of cell size but dependent upon oriented microtubules. A simple, quantitative model of cellular extension driven by microtubules recapitulates cell elongation on lines, the steady-state distribution of microtubules, and cell length homeostasis, and predicts the effects of microtubule inhibitors on cell length. Together this experimental and theoretical analysis suggests that microtubule dynamics impose unexpected limits on cell geometry that enable cells to regulate their length. Since cells are the building blocks and architects of tissue morphogenesis, such intrinsically defined limits may be important for development and homeostasis in multicellular organisms.

  2. Coherent population trapping on 87Rb atoms in small-size absorption cells with buffer gas

    Science.gov (United States)

    Ermak, S. V.; Petrenko, M. V.; Semenov, V. V.

    2016-02-01

    Coherent population trapping (CPT) on 87Rb atoms in neon atmosphere has been studied in small-size glass absorption cells under conditions of pumping with narrow-band laser radiation at the D2 line of the main doublet. Parameters of the absorption signal have been measured in 3-mm-diameter cells at buffer gas (Ne) pressures varied within 200-400 Torr, cell temperatures within 65-120°C, and pumping radiation power densities within 30-400 μW/cm2. Optimum values of the buffer gas pressures, cell temperature, and pumping power are determined at which the short-term instability of the resonance line is at minimum. Orientational shifts of the CPT resonance signal in gas-filled cells and small-size cells with antirelaxation coating have been compared.

  3. gC1qR expression in chimpanzees with resolved and chronic infection: Potential role of HCV core/gC1qR-mediated T cell suppression in the outcome of HCV infection

    International Nuclear Information System (INIS)

    Chimpanzee is a unique animal model for HCV infection, in which about 50% of infections resolve spontaneously. It has been reported that the magnitude of T cell responses to HCV core in recovered chimpanzees is greater than that in chronically infected ones. However, the mechanism(s) by which the chimpanzees with resolved infection overcome core-mediated immunosuppression remains unknown. In this study, we examined the effect of HCV core on T cell responsiveness in chimpanzees with resolved and chronic HCV infection. We found that core protein strongly inhibited T cell activation and proliferation in chimpanzees with chronic infection, while this inhibition was limited in chimpanzees with resolved infection. Notably, the level of gC1qR, as well as the binding of core protein, on the surface of T cells was lower in recovered chimpanzees when compared to chimpanzees with chronic HCV infection. Intriguingly, the observed differences in gC1qR expression levels and susceptibility to core-induced suppression amongst HCV-chronically infected and recovered chimpanzees were observed prior to HCV challenge, suggesting a possible genetic determination of the outcome of infection. These findings suggest that gC1qR expression on the surface of T cells is crucial for HCV core-mediated T cell suppression and viral clearance, and that represents a novel mechanism by which a virus usurps host machinery for persistence

  4. Characterization of a Phenotypically Unique Population of CD13+ Dendritic Cells Resident in the Spleen

    OpenAIRE

    Zhuang, Yan; Mwangi, Waithaka; Brown, Wendy C.; Davis, William C.; Hope, Jayne C.; Palmer, Guy H.

    2006-01-01

    Immature dendritic cells (DCs) resident in bovine spleens represent a distinct CD11a+ CD11c+ CD13+ CD172+ CD205+ population compared to those circulating in peripheral blood or trafficking via afferent lymph. Upon cytokine-induced maturation, splenic DCs both efficiently present antigen in the stimulation of allogeneic lymphocyte proliferation and recall antigen-specific responses.

  5. Tissue-resident adult stem cell populations of rapidly self-renewing organs

    NARCIS (Netherlands)

    Barker, N.; Bartfeld, S.; Clevers, H.

    2010-01-01

    The epithelial lining of the intestine, stomach, and skin is continuously exposed to environmental assault, imposing a requirement for regular self-renewal. Resident adult stem cell populations drive this renewal, and much effort has been invested in revealing their identity. Reliable adult stem cel

  6. Super-resolved 3-D imaging of live cells organelles from bright-field photon transmission micrographs

    CERN Document Server

    Rychtarikova, Renata; Shi, Kevin; Malakhova, Daria; Machacek, Petr; Smaha, Rebecca; Urban, Jan; Stys, Dalibor

    2016-01-01

    Current biological and medical research is aimed at obtaining a detailed spatiotemporal map of a live cell's interior to describe and predict cell's physiological state. We present here an algorithm for complete 3-D modelling of cellular structures from a z-stack of images obtained using label-free wide-field bright-field light-transmitted microscopy. The method visualizes 3-D objects with a volume equivalent to the area of a camera pixel multiplied by the z-height. The computation is based on finding pixels of unchanged intensities between two consecutive images of an object spread function. These pixels represent strongly light-diffracting, light-absorbing, or light-emitting objects. To accomplish this, variables derived from R\\'{e}nyi entropy are used to suppress camera noise. Using this algorithm, the detection limit of objects is only limited by the technical specifications of the microscope setup--we achieve the detection of objects of the size of one camera pixel. This method allows us to obtain 3-D re...

  7. A mathematical model of radiation-induced responses in a cellular population including cell-to-cell communications

    International Nuclear Information System (INIS)

    Cell-to-cell communication is an important factor for understanding the mechanisms of radiation-induced responses such as bystander effects. In this study, a new mathematical model of intercellular signalling between individual cells in a cellular population is proposed. The authors considered two types of transmission of signals: via culture medium and via gap junction. They focus on the effects that radiation and intercellular signalling have on cell-cycle modification. The cell cycle is represented as a virtual clock that includes several checkpoint pathways within a cyclic process. They also develop a grid model and set up diffusion equations to model the propagation of signals to and from spatially located cells. The authors have also considered the role that DNA damage plays in the cycle of cells which can progress through the cell cycle or stop at the G1, S, G2 or M-phase checkpoints. Results of testing show that the proposed model can simulate intercellular signalling and cell-cycle progression in individual cells during and after irradiation. (authors)

  8. Distribution of killer cell immunoglobulin-like receptors genes in the Italian Caucasian population

    Directory of Open Access Journals (Sweden)

    Mariani M

    2006-10-01

    Full Text Available Abstract Background Killer cell immunoglobulin-like receptors (KIRs are a family of inhibitory and activatory receptors that are expressed by most natural killer (NK cells. The KIR gene family is polymorphic: genomic diversity is achieved through differences in gene content and allelic polymorphism. The number of KIR loci has been reported to vary among individuals, resulting in different KIR haplotypes. In this study we report the genotypic structure of KIRs in 217 unrelated healthy Italian individuals from 22 immunogenetics laboratories, located in the northern, central and southern regions of Italy. Methods Two hundred and seventeen DNA samples were studied by a low resolution PCR-SSP kit designed to identify all KIR genes. Results All 17 KIR genes were observed in the population with different frequencies than other Caucasian and non-Caucasian populations; framework genes KIR3DL3, KIR3DP1, KIR2DL4 and KIR3DL2 were present in all individuals. Sixty-five different profiles were found in this Italian population study. Haplotype A remains the most prevalent and genotype 1, with a frequency of 28.5%, is the most commonly observed in the Italian population. Conclusion The Italian Caucasian population shows polymorphism of the KIR gene family like other Caucasian and non-Caucasian populations. Although 64 genotypes have been observed, genotype 1 remains the most frequent as already observed in other populations. Such knowledge of the KIR gene distribution in populations is very useful in the study of associations with diseases and in selection of donors for haploidentical bone marrow transplantation.

  9. Resolving the nanostructure of plasma-enhanced chemical vapor deposited nanocrystalline SiOx layers for application in solar cells

    Science.gov (United States)

    Klingsporn, M.; Kirner, S.; Villringer, C.; Abou-Ras, D.; Costina, I.; Lehmann, M.; Stannowski, B.

    2016-06-01

    Nanocrystalline silicon suboxides (nc-SiOx) have attracted attention during the past years for the use in thin-film silicon solar cells. We investigated the relationships between the nanostructure as well as the chemical, electrical, and optical properties of phosphorous, doped, nc-SiO0.8:H fabricated by plasma-enhanced chemical vapor deposition. The nanostructure was varied through the sample series by changing the deposition pressure from 533 to 1067 Pa. The samples were then characterized by X-ray photoelectron spectroscopy, spectroscopic ellipsometry, Raman spectroscopy, aberration-corrected high-resolution transmission electron microscopy, selected-area electron diffraction, and a specialized plasmon imaging method. We found that the material changed with increasing pressure from predominantly amorphous silicon monoxide to silicon dioxide containing nanocrystalline silicon. The nanostructure changed from amorphous silicon filaments to nanocrystalline silicon filaments, which were found to cause anisotropic electron transport.

  10. B-Cell Activation and Non-Hodgkin Lymphoma Risk in an HIV Positive Population

    OpenAIRE

    Chang, Po-Yin

    2013-01-01

    Background: B-cell non-Hodgkin lymphoma (NHL) in HIV populations (AIDS-NHL) has become the leading cause of AIDS-defining cancers. Studies suggested that genetic or serum markers of B-cell activation are related to AIDS-NHL. However, associations between HIV viral load and AIDS-NHL risk have not been explicitly explored with consideration of B-cell activation markers. Furthermore, associations of hepatitis C virus (HCV) infection to AIDS-NHL risk are inconclusive. Methods: We used two nested ...

  11. Tumor associated antigen specific T-cell populations identified in ex vivo expanded TIL cultures

    DEFF Research Database (Denmark)

    Junker, Niels; Kvistborg, Pia; Køllgaard, Tania;

    2012-01-01

    Ex vivo expanded tumor infiltrating lymphocytes (TILs) from malignant melanoma (MM) and head & neck squamous cell carcinoma (HNSCC) share a similar oligoclonal composition of T effector memory cells, with HLA class I restricted lysis of tumor cell lines. In this study we show that ex vivo expanded...... TILs from MM and HNSCC demonstrate a heterogeneous composition in frequency and magnitude of tumor associated antigen specific populations by Elispot IFN¿ quantitation. TILs from MM and HNSCC shared reactivity towards NY ESO-1, cyclin B1 and Bcl-x derived peptides. Additionally we show that dominating...

  12. Expression of genes encoding multi-transmembrane proteins in specific primate taste cell populations.

    Directory of Open Access Journals (Sweden)

    Bryan D Moyer

    Full Text Available BACKGROUND: Using fungiform (FG and circumvallate (CV taste buds isolated by laser capture microdissection and analyzed using gene arrays, we previously constructed a comprehensive database of gene expression in primates, which revealed over 2,300 taste bud-associated genes. Bioinformatics analyses identified hundreds of genes predicted to encode multi-transmembrane domain proteins with no previous association with taste function. A first step in elucidating the roles these gene products play in gustation is to identify the specific taste cell types in which they are expressed. METHODOLOGY/PRINCIPAL FINDINGS: Using double label in situ hybridization analyses, we identified seven new genes expressed in specific taste cell types, including sweet, bitter, and umami cells (TRPM5-positive, sour cells (PKD2L1-positive, as well as other taste cell populations. Transmembrane protein 44 (TMEM44, a protein with seven predicted transmembrane domains with no homology to GPCRs, is expressed in a TRPM5-negative and PKD2L1-negative population that is enriched in the bottom portion of taste buds and may represent developmentally immature taste cells. Calcium homeostasis modulator 1 (CALHM1, a component of a novel calcium channel, along with family members CALHM2 and CALHM3; multiple C2 domains; transmembrane 1 (MCTP1, a calcium-binding transmembrane protein; and anoctamin 7 (ANO7, a member of the recently identified calcium-gated chloride channel family, are all expressed in TRPM5 cells. These proteins may modulate and effect calcium signalling stemming from sweet, bitter, and umami receptor activation. Synaptic vesicle glycoprotein 2B (SV2B, a regulator of synaptic vesicle exocytosis, is expressed in PKD2L1 cells, suggesting that this taste cell population transmits tastant information to gustatory afferent nerve fibers via exocytic neurotransmitter release. CONCLUSIONS/SIGNIFICANCE: Identification of genes encoding multi-transmembrane domain proteins

  13. Analysis of rare high-DNA cell populations in serous effusions using continuous-motion imaging.

    Science.gov (United States)

    Tucker, J H; Stark, M H; Eason, P; Duvall, E

    1991-07-01

    The rare high-DNA cell sub-populations in a series of serous effusion specimens were analysed to determine whether such measurements could provide a basis for the improved diagnosis of malignancy. Monolayer specimens stained with gallocyanin chrome-alum were scanned with the CERVIFIP continuous-motion image analyser to locate and measure the highest-DNA cells in the sample. Two types of features were obtained for the detected sub-populations; firstly, 'percentile ploidy' values which characterise the ploidy levels above which specified proportions of the total cells are found; and secondly 'percentage abnormal' values which characterise the proportion of the cells diagnosed as malignant during examination by a cytopathologist. The classification accuracy for one or both of these features was then obtained by comparison with the clinical outcome of each patient. The results gave a classification error of 9/44 (20%) using the 0.01% percentile ploidy alone, 6/44 (14%) using the 75% percentage abnormal feature alone, but only 2/44 (5%) from a box discriminant using both features. It was therefore concluded that the analysis of the high-DNA cell population could be of value in the diagnosis of malignancy in serous effusion specimens. PMID:1883747

  14. Hypoxia promotes growth of stem cells in dental follicle cell populations

    OpenAIRE

    Dai, Yuntao; He, Hongzhi; Wise, Gary E.; Yao, Shaomian

    2011-01-01

    Adult stem cells (ASC) have been found in many tissues and are of great therapeutic potential due to their capability of differentiation. However, ASC comprise only a small fraction of the tissues. In order to use ASC for therapeutic purposes, it is important to obtain relatively pure stem cells in large quantities. Current methods for stem cell purification are mainly based on marker-dependent cell sorting techniques, which have various technical difficulties. In this study, we have attempte...

  15. Cell competition modifies adult stem cell and tissue population dynamics in a JAKSTAT dependent manner

    OpenAIRE

    Kolahgar, Golnar; Suijkerbuijk, Saskia J. E.; Kucinski, Iwo; Poirier, Enzo Z.; Mansour, Sarah; Simons, Benjamin D.; Piddini, Eugenia

    2015-01-01

    Summary Throughout their lifetime, cells may suffer insults that reduce their fitness and disrupt their function, and it is unclear how these potentially harmful cells are managed in adult tissues. We address this question using the adult Drosophila posterior midgut as a model of homeostatic tissue and ribosomal Minute mutations to reduce fitness in groups of cells. We take a quantitative approach combining lineage tracing and biophysical modeling and address how cell competition affects stem...

  16. A Population Dynamics Analysis of the Interaction between Adaptive Regulatory T Cells and Antigen Presenting Cells

    OpenAIRE

    Fouchet, David; Regoes, Roland

    2008-01-01

    Background Regulatory T cells are central actors in the maintenance of tolerance of self-antigens or allergens and in the regulation of the intensity of the immune response during infections by pathogens. An understanding of the network of the interaction between regulatory T cells, antigen presenting cells and effector T cells is starting to emerge. Dynamical systems analysis can help to understand the dynamical properties of an interaction network and can shed light on the different tasks t...

  17. A novel cell-based duplex high-throughput screening assay combining fluorescent Ca(2+) measurement with homogeneous time-resolved fluorescence technology.

    Science.gov (United States)

    Kiss, László; Cselenyák, Attila; Varga, Ágnes; Visegrády, András

    2016-08-15

    Cell-based assays for G-protein-coupled receptor (GPCR) activation applied in high-throughput screening (HTS) monitor various readouts for second messengers or intracellular effectors. Recently, our understanding of diverging signaling pathways downstream of receptor activation and the capability of small molecules to selectively modulate signaling routes has increased substantially, underlining the importance of selecting appropriate readouts in cellular functional screens. To minimize the rate of false negatives in large-scale screening campaigns, it is crucial to maximize the chance of a ligand being detected, and generally applicable methods for detecting multiple analytes from a single well might serve this purpose. The few assays developed so far based on multiplexed GPCR readouts are limited to only certain applications and usually rely on genetic manipulations hindering screening in native or native-like cellular systems. Here we describe a more generally applicable and HTS-compatible homogeneous assay based on the combination of fluorometric detection of [Ca(2+)] with subsequent homogeneous time-resolved fluorescence (HTRF) cAMP readout in the same well. Besides describing development and validation of the assay, using a cell line recombinantly expressing the human PTH1 receptor screening of a small library is also presented, demonstrating the robustness and HTS compatibility of the novel paradigm. PMID:27235172

  18. Genetic barcode sequencing for screening altered population dynamics of hematopoietic stem cells transduced with lentivirus

    Science.gov (United States)

    Zanatta, Daniela B; Tsujita, Maristela; Borelli, Primavera; Aguiar, Rodrigo B; Ferrari, Daniel G; Strauss, Bryan E

    2014-01-01

    Insertional mutagenesis has been associated with malignant cell transformation in gene therapy protocols, leading to discussions about vector security. Therefore, clonal analysis is important for the assessment of vector safety and its impact on patient health. Here, we report a unique approach to assess dynamic changes in clonality of lentivirus transduced cells upon Sanger sequence analysis of a specially designed genetic barcode. In our approach, changes in the electropherogram peaks are measured and compared between successive time points, revealing alteration in the cell population. After in vitro validation, barcoded lentiviral libraries carrying IL2RG or LMO2 transgenes, or empty vector were used to transduce mouse hematopoietic (ckit+) stem cells, which were subsequently transplanted in recipient mice. We found that neither the empty nor IL2RG encoding vector had an effect on cell dynamics. In sharp contrast, the LMO2 oncogene was associated with altered cell dynamics even though hematologic counts remained unchanged, suggesting that the barcode could reveal changes in cell populations not observed by the frontline clinical assay. We describe a simple and sensitive method for the analysis of clonality, which could be easily used by any laboratory for the assessment of cellular behavior upon lentiviral transduction. PMID:26052520

  19. Determination of the PSI/PSII ratio in living plant cells at room temperature by spectrally resolved fluorescence spectroscopy

    Science.gov (United States)

    Elgass, Kirstin; Zell, Martina; Maurino, Veronica G.; Schleifenbaum, Frank

    2011-02-01

    Leaf cells of living plants exhibit strong fluorescence from chloroplasts, the reaction centers of photosynthesis. Mutations in the photosystems change their structure and can, thus, be monitored by recording the fluorescence spectra of the emitted chlorophyll light. These measurements have, up to now, mostly been carried out at low temperatures (77 K), as these conditions enable the differentiation between the fluorescence of Photosystem I (PSI) and Photosystem II (PSII). In contrast, at room temperature, energy transfer processes between the various photosynthetic complexes result in very similar fluorescence emissions, which mainly consist of fluorescence photons emitted by PSII hindering a discrimination based on spectral ROIs (regions of interest). However, by statistical analysis of high resolution fluorescence spectra recorded at room temperature, it is possible to draw conclusions about the relative PSI/PSII ratio. Here, the possibility of determining the relative PSI/PSII ratio by fluorescence spectroscopy is demonstrated in living maize plants. Bundle-sheath chloroplasts of mature maize plants have a special morphologic characteristic; they are agranal, or exhibit only rudimentary grana, respectively. These chloroplasts are depleted in PSII activity and it could be shown that PSII is progressively reduced during leaf differentiation. A direct comparison of PSII activity in isolated chloroplasts is nearly impossible, since the activity of PSII in both mesophyll- and bundle-sheath chloroplasts decays with time after isolation and it takes significantly longer to isolate bundle-sheath chloroplasts. Considering this fact the measurement of PSI/PSII ratios with the 77K method, which includes taking fluorescence spectra from a diluted suspension of isolated chloroplasts at 77K, is questionable. These spectra are then used to analyze the distribution of energy between PSI and PSII. After rapid cooling to 77K secondary biochemical influences, which attenuate the

  20. 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...

  1. 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...

  2. Tumor-initiating cells are enriched in CD44(hi population in murine salivary gland tumor.

    Directory of Open Access Journals (Sweden)

    Shukun Shen

    Full Text Available Tumor-initiating cells (T-ICs discovered in various tumors have been widely reported. However, T-IC populations in salivary gland tumors have yet to be elucidated. Using the established Pleomorphic Adenoma Gene-1 (Plag1 transgenic mouse model of a salivary gland tumor, we identified CD44(high (CD44(hi tumor cells, characterized by high levels of CD44 cell surface expression, as the T-ICs for pleomorphic adenomas. These CD44(hi tumor cells incorporated 5-bromo-2-deoxyuridine (BrdU, at a lower rate than their CD44(negative (CD44(neg counterparts, and also retained BrdU for a long period of time. Cell surface maker analysis revealed that 25% of the CD44(hi tumor cells co-express other cancer stem cell markers such as CD133 and CD117. As few as 500 CD44(hi tumor cells were sufficient to initiate pleomorphic adenomas in one third of the wildtype mice, whereas more than 1×10(4 CD44(neg cells were needed for the same purpose. In NIH 3T3 cells, Plag1 was capable of activating the gene transcription of Egr1, a known upregulator for CD44. Furthermore, deletion of sequence 81-96 in the Egr1 promoter region abolished the effect of Plag1 on Egr1 upregulation. Our results establish the existence of T-ICs in murine salivary gland tumors, and suggest a potential molecular mechanism for CD44 upregulation.

  3. Robust detection of alternative splicing in a population of single cells.

    Science.gov (United States)

    Welch, Joshua D; Hu, Yin; Prins, Jan F

    2016-05-01

    Single cell RNA-seq experiments provide valuable insight into cellular heterogeneity but suffer from low coverage, 3' bias and technical noise. These unique properties of single cell RNA-seq data make study of alternative splicing difficult, and thus most single cell studies have restricted analysis of transcriptome variation to the gene level. To address these limitations, we developed SingleSplice, which uses a statistical model to detect genes whose isoform usage shows biological variation significantly exceeding technical noise in a population of single cells. Importantly, SingleSplice is tailored to the unique demands of single cell analysis, detecting isoform usage differences without attempting to infer expression levels for full-length transcripts. Using data from spike-in transcripts, we found that our approach detects variation in isoform usage among single cells with high sensitivity and specificity. We also applied SingleSplice to data from mouse embryonic stem cells and discovered a set of genes that show significant biological variation in isoform usage across the set of cells. A subset of these isoform differences are linked to cell cycle stage, suggesting a novel connection between alternative splicing and the cell cycle. PMID:26740580

  4. Persistence of side population cells with high drug efflux capacity in pancreatic cancer

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    AIM:To investigate the persistence of side population (SP) cells in pancreatic cancer and their role and mechanism in the drug resistance.METHODS:The presentation of side population cells in pancreatic cancer cell line PANC-1 and its proportion change when cultured with Gemcitabine,was detected by Hoechst 33342 staining and FACS analysis.The expression of ABCB1 and ABCG2 was detected by realtime PCR in either SP cells or non-SP cells.RESULTS:SP cells do exist in PANC-1,with a median of 3.3% and a range of 2.1-8.7%.After cultured with Gemcitabine for 3 d,the proportion of SP cells increased significantly(3.8% ± 1.9%,10.7% ± 3.7%, t = 4.616,P = 0.001 < 0.05).ABCB1 and ABCG2 expressed at higher concentrations in SP as compared with non-SP cells (ABCBI: 1.15 ± 0.72, 5.82 ± 1.16, t = 10.839,P = 0.000 < 0.05; ABCG2:1.16 ± 0.75,5.48 ± 0.94,t = 11.305,P = 0.000 < 0.05),which may contribute to the efflux of fluorescent staining and drug resistance.CONCLUSION:SP cells with inherently high resistance to chemotherapeutic agents do exist in pancreatic cancers,which may be candidate cancer stem cells contributing to the relapse of the tumor.

  5. CELLULAR AND POPULATION PLASTICITY OF HELPER CD4 T CELL RESPONSES

    Directory of Open Access Journals (Sweden)

    Gesham eMagombedze

    2013-08-01

    Full Text Available Vertebrates are constantly exposed to pathogens, and the adaptive immunity has most likely evolved to control and clear such infectious agents. CD4 T cells are the major players in the adaptive immune response to pathogens. Following recognition of pathogen-derived antigens naïve CD4 T cells differentiate into effectors which then control pathogen replication either directly by killing pathogen-infected cells or by assisting with generation of cytotoxic T lymphocytes or pathogen-specific antibodies. Pathogen-specific effector CD4 T cells are highly heterogeneous in terms of cytokines they produce. Three major subtypes of effector CD4 T cells have been identified: T-helper 1 (Th1 cells producing IFN-g and TNF-α, Th2 cells producing IL-4 and IL-10, and Th17 cells producing IL-17. How this heterogeneity is maintained and what regulates changes in effector T cell composition during chronic infections remains poorly understood. In this review we discuss recent advances in our understanding of CD4 T cell differentiation in response to microbial infections. We propose that a change in the phenotype of pathogen-specific effector CD4 T cells during chronic infections, for example, from Th1 to Th2 response as observed in Mycobacteriumavium ssp. paratuberculosis (MAP infection of ruminants, can be achieved by conversion of T cells from one effector subset to another (cellular plasticity or due to differences in kinetics (differentiation, proliferation, death of different effector T cell subsets (population plasticity. We also shortly review mathematical models aimed at describing CD4 T cell differentiation and outline areas for future experimental and theoretical research.

  6. Population based model of human embryonic stem cell (hESC differentiation during endoderm induction.

    Directory of Open Access Journals (Sweden)

    Keith Task

    Full Text Available The mechanisms by which human embryonic stem cells (hESC differentiate to endodermal lineage have not been extensively studied. Mathematical models can aid in the identification of mechanistic information. In this work we use a population-based modeling approach to understand the mechanism of endoderm induction in hESC, performed experimentally with exposure to Activin A and Activin A supplemented with growth factors (basic fibroblast growth factor (FGF2 and bone morphogenetic protein 4 (BMP4. The differentiating cell population is analyzed daily for cellular growth, cell death, and expression of the endoderm proteins Sox17 and CXCR4. The stochastic model starts with a population of undifferentiated cells, wherefrom it evolves in time by assigning each cell a propensity to proliferate, die and differentiate using certain user defined rules. Twelve alternate mechanisms which might describe the observed dynamics were simulated, and an ensemble parameter estimation was performed on each mechanism. A comparison of the quality of agreement of experimental data with simulations for several competing mechanisms led to the identification of one which adequately describes the observed dynamics under both induction conditions. The results indicate that hESC commitment to endoderm occurs through an intermediate mesendoderm germ layer which further differentiates into mesoderm and endoderm, and that during induction proliferation of the endoderm germ layer is promoted. Furthermore, our model suggests that CXCR4 is expressed in mesendoderm and endoderm, but is not expressed in mesoderm. Comparison between the two induction conditions indicates that supplementing FGF2 and BMP4 to Activin A enhances the kinetics of differentiation than Activin A alone. This mechanistic information can aid in the derivation of functional, mature cells from their progenitors. While applied to initial endoderm commitment of hESC, the model is general enough to be applicable

  7. An imbalance in progenitor cell populations reflects tumour progression in breast cancer primary culture models

    LENUS (Irish Health Repository)

    Donatello, Simona

    2011-04-26

    Abstract Background Many factors influence breast cancer progression, including the ability of progenitor cells to sustain or increase net tumour cell numbers. Our aim was to define whether alterations in putative progenitor populations could predict clinicopathological factors of prognostic importance for cancer progression. Methods Primary cultures were established from human breast tumour and adjacent non-tumour tissue. Putative progenitor cell populations were isolated based on co-expression or concomitant absence of the epithelial and myoepithelial markers EPCAM and CALLA respectively. Results Significant reductions in cellular senescence were observed in tumour versus non-tumour cultures, accompanied by a stepwise increase in proliferation:senescence ratios. A novel correlation between tumour aggressiveness and an imbalance of putative progenitor subpopulations was also observed. Specifically, an increased double-negative (DN) to double-positive (DP) ratio distinguished aggressive tumours of high grade, estrogen receptor-negativity or HER2-positivity. The DN:DP ratio was also higher in malignant MDA-MB-231 cells relative to non-tumourogenic MCF-10A cells. Ultrastructural analysis of the DN subpopulation in an invasive tumour culture revealed enrichment in lipofuscin bodies, markers of ageing or senescent cells. Conclusions Our results suggest that an imbalance in tumour progenitor subpopulations imbalances the functional relationship between proliferation and senescence, creating a microenvironment favouring tumour progression.

  8. Characterization of Cs vapor cell coated with octadecyltrichlorosilane using coherent population trapping spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hafiz, Moustafa Abdel; Maurice, Vincent; Chutani, Ravinder; Passilly, Nicolas; Gorecki, Christophe; Boudot, Rodolphe [FEMTO-ST, CNRS, UFC, 26 Chemin de l' Epitaphe, 25030 Besançon Cedex (France); Guérandel, Stéphane; Clercq, Emeric de [LNE-SYRTE, Observatoire de Paris, CNRS, UPMC, 61 avenue de l' Observatoire, 75014 Paris (France)

    2015-05-14

    We report the realization and characterization using coherent population trapping (CPT) spectroscopy of an octadecyltrichlorosilane (OTS)-coated centimeter-scale Cs vapor cell. The dual-structure of the resonance lineshape, with presence of a narrow structure line at the top of a Doppler-broadened structure, is clearly observed. The linewidth of the narrow resonance is compared to the linewidth of an evacuated Cs cell and of a buffer gas Cs cell of similar size. The Cs-OTS adsorption energy is measured to be (0.42 ± 0.03) eV, leading to a clock frequency shift rate of 2.7 × 10{sup −9}/K in fractional unit. A hyperfine population lifetime, T{sub 1}, and a microwave coherence lifetime, T{sub 2}, of 1.6 and 0.5 ms are reported, corresponding to about 37 and 12 useful bounces, respectively. Atomic-motion induced Ramsey narrowing of dark resonances is observed in Cs-OTS cells by reducing the optical beam diameter. Ramsey CPT fringes are detected using a pulsed CPT interrogation scheme. Potential applications of the Cs-OTS cell to the development of a vapor cell atomic clock are discussed.

  9. 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...

  10. Accounting for randomness in measurement and sampling in studying cancer cell population dynamics.

    Science.gov (United States)

    Ghavami, Siavash; Wolkenhauer, Olaf; Lahouti, Farshad; Ullah, Mukhtar; Linnebacher, Michael

    2014-10-01

    Knowing the expected temporal evolution of the proportion of different cell types in sample tissues gives an indication about the progression of the disease and its possible response to drugs. Such systems have been modelled using Markov processes. We here consider an experimentally realistic scenario in which transition probabilities are estimated from noisy cell population size measurements. Using aggregated data of FACS measurements, we develop MMSE and ML estimators and formulate two problems to find the minimum number of required samples and measurements to guarantee the accuracy of predicted population sizes. Our numerical results show that the convergence mechanism of transition probabilities and steady states differ widely from the real values if one uses the standard deterministic approach for noisy measurements. This provides support for our argument that for the analysis of FACS data one should consider the observed state as a random variable. The second problem we address is about the consequences of estimating the probability of a cell being in a particular state from measurements of small population of cells. We show how the uncertainty arising from small sample sizes can be captured by a distribution for the state probability. PMID:25257023

  11. Endothelial Side Population Cells Contribute to Tumor Angiogenesis and Antiangiogenic Drug Resistance.

    Science.gov (United States)

    Naito, Hisamichi; Wakabayashi, Taku; Kidoya, Hiroyasu; Muramatsu, Fumitaka; Takara, Kazuhiro; Eino, Daisuke; Yamane, Keitaro; Iba, Tomohiro; Takakura, Nobuyuki

    2016-06-01

    Angiogenesis plays a crucial role in tumor growth, with an undisputed contribution of resident endothelial cells (EC) to new blood vessels in the tumor. Here, we report the definition of a small population of vascular-resident stem/progenitor-like EC that contributes predominantly to new blood vessel formation in the tumor. Although the surface markers of this population are similar to other ECs, those from the lung vasculature possess colony-forming ability in vitro and contribute to angiogenesis in vivo These specific ECs actively proliferate in lung tumors, and the percentage of this population significantly increases in the tumor vasculature relative to normal lung tissue. Using genetic recombination and bone marrow transplant models, we show that these cells are phenotypically true ECs and do not originate from hematopoietic cells. After treatment of tumors with antiangiogenic drugs, these specific ECs selectively survived and remained in the tumor. Together, our results established that ECs in the peripheral vasculature are heterogeneous and that stem/progenitor-like ECs play an indispensable role in tumor angiogenesis as EC-supplying cells. The lack of susceptibility of these ECs to antiangiogenic drugs may account for resistance of the tumor to this drug type. Thus, inhibiting these ECs might provide a promising strategy to overcome antiangiogenic drug resistance. Cancer Res; 76(11); 3200-10. ©2016 AACR. PMID:27197162

  12. A novel stem cell source for vasculogenesis in ischemia: subfraction of side population cells from dental pulp.

    Science.gov (United States)

    Iohara, Koichiro; Zheng, Li; Wake, Hiroaki; Ito, Masataka; Nabekura, Junichi; Wakita, Hideaki; Nakamura, Hiroshi; Into, Takeshi; Matsushita, Kenji; Nakashima, Misako

    2008-09-01

    Cell therapy with stem cells and endothelial progenitor cells (EPCs) to stimulate vasculogenesis as a potential treatment for ischemic disease is an exciting area of research in regenerative medicine. EPCs are present in bone marrow, peripheral blood, and adipose tissue. Autologous EPCs, however, are obtained by invasive biopsy, a potentially painful procedure. An alternative approach is proposed in this investigation. Permanent and deciduous pulp tissue is easily available from teeth after extraction without ethical issues and has potential for clinical use. We isolated a highly vasculogenic subfraction of side population (SP) cells based on CD31 and CD146, from dental pulp. The CD31(-);CD146(-) SP cells, demonstrating CD34+ and vascular endothelial growth factor-2 (VEGFR2)/Flk1+, were similar to EPCs. These cells were distinct from the hematopoietic lineage as CD11b, CD14, and CD45 mRNA were not expressed. They showed high proliferation and migration activities and multilineage differentiation potential including vasculogenic potential. In models of mouse hind limb ischemia, local transplantation of this subfraction of SP cells resulted in successful engraftment and an increase in the blood flow including high density of capillary formation. The transplanted cells were in proximity of the newly formed vasculature and expressed several proangiogenic factors, such as VEGF-A, G-CSF, GM-CSF, and MMP3. Conditioned medium from this subfraction showed the mitogenic and antiapoptotic activity on human umbilical vein endothelial cells. In conclusion, subfraction of SP cells from dental pulp is a new stem cell source for cell-based therapy to stimulate angiogenesis/vasculogenesis during tissue regeneration. PMID:18583536

  13. microRNA Expression Profiling of Side Population Cells in Human Lung Cancer and Preliminary Analysis

    Directory of Open Access Journals (Sweden)

    Xiaotao XU

    2010-07-01

    Full Text Available Background and objective Recent studies indicate that the side population (SP which is an enriched source of cancer stem cells (CSCs is the root cause of tumor growth and development. SP appears to be highly resistant to chemo- and radio-therapy which becomes an important factor in tumor recurrence and metastasis. The aim of this study is to determine the difference of microRNA expression profiles between SP cells and non-SP cells so as to lay necessary basis for research on the function of miRNA in lung cancer stem cells. Methods SP and non-SP cells were isolated using flow cytometry and Hoechst 33342 dye efflux assay from human lung adenocarcinoma A549 cell. The total RNA was extracted. The microarray detection system was employed to analyze whether there was difference in miRNA expression profile between SP and non-SP cells. Results A total of 85 differentially expressed miRNA were found, including 32 over-expression and 53 low-expression miRNA in SP. Conclusion miRNA may play important roles in tumorigenesis of lung cancer stem cell. The study of miRNA contributes to elucidate the molecular mechanism of lung cancer stem cell.

  14. Ab initio phenomenological simulation of the growth of large tumor cell populations

    CERN Document Server

    Chignola, R; Milotti, E; Pellegrina, C D; Chignola, Roberto; Fabbro, Alessio Del; Milotti, Edoardo; Pellegrina, Chiara Dalla

    2007-01-01

    In a previous paper we have introduced a phenomenological model of cell metabolism and of the cell cycle to simulate the behavior of large tumor cell populations (Chignola R and Milotti E, Phys. Biol. 2 (2005) 8-22). Here we describe a refined and extended version of the model that includes some of the complex interactions between cells and their surrounding environment. The present version takes into consideration several additional energy-consuming biochemical pathways such as protein and DNA synthesis, the tuning of extracellular pH and of the cell membrane potential. The control of the cell cycle - that was previously modeled by means of ad hoc thresholds - has been directly addressed here by considering checkpoints from proteins that act as targets for phosphorylation on multiple sites. As simulated cells grow, they can now modify the chemical composition of the surrounding environment which in turn acts as a feedback mechanism to tune cell metabolism and hence cell proliferation: in this way we obtain g...

  15. Monitoring intracellular calcium ion dynamics in hair cell populations with Fluo-4 AM.

    Directory of Open Access Journals (Sweden)

    Kateri J Spinelli

    Full Text Available We optimized Fluo-4 AM loading of chicken cochlea to report hair-bundle Ca(2+ signals in populations of hair cells. The bundle Ca(2+ signal reported the physiological state of the bundle and cell; extruding cells had very high bundle Fluo-4 fluorescence, cells with intact bundles and tip links had intermediate fluorescence, and damaged cells with broken tip links had low fluorescence. Moreover, Fluo-4 fluorescence in the bundle correlated with Ca(2+ entry through transduction channels; mechanically activating transduction channels increased the Fluo-4 signal, while breaking tip links with Ca(2+ chelators or blocking Ca(2+ entry through transduction channels each caused bundle and cell-body Fluo-4 fluorescence to decrease. These results show that when tip links break, bundle and soma Ca(2+ decrease, which could serve to stimulate the hair cell's tip-link regeneration process. Measurement of bundle Ca(2+ with Fluo-4 AM is therefore a simple method for assessing mechanotransduction in hair cells and permits an increased understanding of the interplay of tip links, transduction channels, and Ca(2+ signaling in the hair cell.

  16. Two-Step Regulation of a Meristematic Cell Population Acting in Shoot Branching in Arabidopsis.

    Science.gov (United States)

    Shi, Bihai; Zhang, Cui; Tian, Caihuan; Wang, Jin; Wang, Quan; Xu, Tengfei; Xu, Yan; Ohno, Carolyn; Sablowski, Robert; Heisler, Marcus G; Theres, Klaus; Wang, Ying; Jiao, Yuling

    2016-07-01

    Shoot branching requires the establishment of new meristems harboring stem cells; this phenomenon raises questions about the precise regulation of meristematic fate. In seed plants, these new meristems initiate in leaf axils to enable lateral shoot branching. Using live-cell imaging of leaf axil cells, we show that the initiation of axillary meristems requires a meristematic cell population continuously expressing the meristem marker SHOOT MERISTEMLESS (STM). The maintenance of STM expression depends on the leaf axil auxin minimum. Ectopic expression of STM is insufficient to activate axillary buds formation from plants that have lost leaf axil STM expressing cells. This suggests that some cells undergo irreversible commitment to a developmental fate. In more mature leaves, REVOLUTA (REV) directly up-regulates STM expression in leaf axil meristematic cells, but not in differentiated cells, to establish axillary meristems. Cell type-specific binding of REV to the STM region correlates with epigenetic modifications. Our data favor a threshold model for axillary meristem initiation, in which low levels of STM maintain meristematic competence and high levels of STM lead to meristem initiation. PMID:27398935

  17. Connecting multiple spatial scales to decode the population activity of grid cells.

    Science.gov (United States)

    Stemmler, Martin; Mathis, Alexander; Herz, Andreas V M

    2015-12-01

    Mammalian grid cells fire when an animal crosses the points of an imaginary hexagonal grid tessellating the environment. We show how animals can navigate by reading out a simple population vector of grid cell activity across multiple spatial scales, even though neural activity is intrinsically stochastic. This theory of dead reckoning explains why grid cells are organized into discrete modules within which all cells have the same lattice scale and orientation. The lattice scale changes from module to module and should form a geometric progression with a scale ratio of around 3/2 to minimize the risk of making large-scale errors in spatial localization. Such errors should also occur if intermediate-scale modules are silenced, whereas knocking out the module at the smallest scale will only affect spatial precision. For goal-directed navigation, the allocentric grid cell representation can be readily transformed into the egocentric goal coordinates needed for planning movements. The goal location is set by nonlinear gain fields that act on goal vector cells. This theory predicts neural and behavioral correlates of grid cell readout that transcend the known link between grid cells of the medial entorhinal cortex and place cells of the hippocampus. PMID:26824061

  18. Cell cycle delays in synchronized cell populations following irradiation with heavy ions

    International Nuclear Information System (INIS)

    Mammalian cells subjected to irradiation with heavy ions were investigated for cell cycle delays. The ions used for this purpose included Ne ions in the LET range of 400 keV/μm just as well as uranium ions of 16225 keV/μm. The qualitative changes in cell cycle progression seen after irradiation with Ne ions (400 keV/μm) were similar to those observed in connection with X-rays. Following irradiation with extremely heavy ions (lead, uranium) the majority of cells were even at 45 hours still found to be in the S phase or G2M phase of the first cycle. The delay cross section 'σ-delay' was introduced as a quantity that would permit quantitative comparisons to be carried out between the changes in cell progression and other effects of radiation. In order to evaluate the influence of the number of hits on the radiation effect observed, the size of the cell nucleus was precisely determined with reference to the cycle phase and local cell density. A model to simulate those delay effects was designed in such a way that account is taken of this probability of hit and that the results can be extrapolated from the delay effects after X-irradiation. On the basis of the various probabilities of hit for cells at different cycle stages a model was developed to ascertain the intensified effect following fractionated irradiation with heavy ions. (orig./MG)

  19. Dual-modality wide-field photothermal quantitative phase microscopy and depletion of cell populations

    Science.gov (United States)

    Turko, Nir A.; Barnea, Itay; Blum, Omry; Korenstein, Rafi; Shaked, Natan T.

    2015-03-01

    We review our dual-modality technique for quantitative imaging and selective depletion of populations of cells based on wide-field photothermal (PT) quantitative phase imaging and simultaneous PT cell extermination. The cells are first labeled by plasmonic gold nanoparticles, which evoke local plasmonic resonance when illuminated by light in a wavelength corresponding to their specific plasmonic resonance peak. This reaction creates changes of temperature, resulting in changes of phase. This phase changes are recorded by a quantitative phase microscope (QPM), producing specific imaging contrast, and enabling bio-labeling in phase microscopy. Using this technique, we have shown discrimination of EGFR over-expressing (EGFR+) cancer cells from EGFR under-expressing (EGFR-) cancer cells. Then, we have increased the excitation power in order to evoke greater temperatures, which caused specific cell death, all under real-time phase acquisition using QPM. Close to 100% of all EGFR+ cells were immediately exterminated when illuminated with the strong excitation beam, while all EGFR- cells survived. For the second experiment, in order to simulate a condition where circulating tumor cells (CTCs) are present in blood, we have mixed the EGFR+ cancer cells with white blood cells (WBCs) from a healthy donor. Here too, we have used QPM to observe and record the phase of the cells as they were excited for selective visualization and then exterminated. The WBCs survival rate was over 95%, while the EGFR+ survival rate was under 5%. The technique may be the basis for real-time detection and controlled treatment of CTCs.

  20. A phenomenological approach to the simulation of metabolism and proliferation dynamics of large tumour cell populations

    CERN Document Server

    Chignola, R; Chignola, Roberto; Milotti, Edoardo

    2005-01-01

    A major goal of modern computational biology is to simulate the collective behaviour of large cell populations starting from the intricate web of molecular interactions occurring at the microscopic level. In this paper we describe a simplified model of cell metabolism, growth and proliferation, suitable for inclusion in a multicell simulator, now under development (Chignola R and Milotti E 2004 Physica A 338 261-6). Nutrients regulate the proliferation dynamics of tumor cells which adapt their behaviour to respond to changes in the biochemical composition of the environment. This modeling of nutrient metabolism and cell cycle at a mesoscopic scale level leads to a continuous flow of information between the two disparate spatiotemporal scales of molecular and cellular dynamics that can be simulated with modern computers and tested experimentally.

  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. Glioblastoma formation from cell population depleted of Prominin1-expressing cells.

    Directory of Open Access Journals (Sweden)

    Kenji Nishide

    Full Text Available Prominin1 (Prom1, also known as CD133 in human has been widely used as a marker for cancer stem cells (CSCs, which self-renew and are tumorigenic, in malignant tumors including glioblastoma multiforme (GBM. However, there is other evidence showing that Prom1-negative cancer cells also form tumors in vivo. Thus it remains controversial whether Prom1 is a bona fide marker for CSCs. To verify if Prom1-expressing cells are essential for tumorigenesis, we established a mouse line, whose Prom1-expressing cells can be eliminated conditionally by a Cre-inducible DTA gene on the Prom1 locus together with a tamoxifen-inducible CreER(TM, and generated glioma-initiating cells (GICs-LD by overexpressing both the SV40 Large T antigen and an oncogenic H-Ras(L61 in neural stem cells of the mouse line. We show here that the tamoxifen-treated GICs-LD (GICs-DTA form tumor-spheres in culture and transplantable GBM in vivo. Thus, our studies demonstrate that Prom1-expressing cells are dispensable for gliomagenesis in this mouse model.

  3. Juvenile Myelomonocytic Leukemia (JMML Cells Spontaneously Differentiate into Dendritic-Cell Like Populations in vitro

    Directory of Open Access Journals (Sweden)

    Parviz Shayan

    2008-09-01

    Full Text Available Objective: Juvenile myelomonocytic leukemia (JMML is a rare myelodysplastic/ myeloproliferative malignancy of early childhood, characterized by monocytosis, hepatosplenomegaly and an aggressive clinical course. Methods: In semi-solid culture JMML progenitor cells proliferate spontaneously into colony forming units. In order to study the mechanisms of proliferation and differentiation of JMML cells we developed a suspension culture system without additional exogenous growth factor supplement. Mononuclear cells (MNC from peripheral blood, bone marrow or spleen of 14 patients with JMML and 24 controls were studied. Findings: JMML cells expressed higher levels of the proliferation marker Ki67 (median 24% [7-39%] vs a median of 3.5% in controls. 90% of JMML cells were CD68-positive (vs 35% in controls and by day 7 all JMML samples contained CD1a- positive cells. Electron microscopy demonstrated cytoplasmic vesicular structures resembling multilamellar MHC II compare­timents, which together with the expression of CD1a - support a dendritic cell (DC-phenotype. Conclusion: Differentiation into CD1a-positive DC seems to be a frequent phenomenon in cultured JMML MNC, which in vivo may contribute to clinical characteristics such as skin and organ infiltration.

  4. Molecular Genetic Characterization of β-Thalassemia and Sickle Cell Syndrome in the Albanian Population

    OpenAIRE

    Babameto-Laku, A; Mitre, A; Berisha, S; Mokini, V; Roko, D

    2011-01-01

    β-Thalassemia (β-thal) is a major public health problem in Albania as it is in many Mediterranean countries. We determined the different β-thal alleles that are present in the Albanian population by using the temporal temperature gradient electrophoresis (TTGE) method because of its high throughput, cost-effectiveness, sensitivity and simplicity. DNA from blood of 68 patients with β-thal, 26 with sickle cell anemia or sickle cell β-thal, 54 parents of these patients and 14 heterozygotes relat...

  5. Stochastic adaptation and fold-change detection: from single-cell to population behavior

    Directory of Open Access Journals (Sweden)

    Leier André

    2011-02-01

    Full Text Available Abstract Background In cell signaling terminology, adaptation refers to a system's capability of returning to its equilibrium upon a transient response. To achieve this, a network has to be both sensitive and precise. Namely, the system must display a significant output response upon stimulation, and later on return to pre-stimulation levels. If the system settles at the exact same equilibrium, adaptation is said to be 'perfect'. Examples of adaptation mechanisms include temperature regulation, calcium regulation and bacterial chemotaxis. Results We present models of the simplest adaptation architecture, a two-state protein system, in a stochastic setting. Furthermore, we consider differences between individual and collective adaptive behavior, and show how our system displays fold-change detection properties. Our analysis and simulations highlight why adaptation needs to be understood in terms of probability, and not in strict numbers of molecules. Most importantly, selection of appropriate parameters in this simple linear setting may yield populations of cells displaying adaptation, while single cells do not. Conclusions Single cell behavior cannot be inferred from population measurements and, sometimes, collective behavior cannot be determined from the individuals. By consequence, adaptation can many times be considered a purely emergent property of the collective system. This is a clear example where biological ergodicity cannot be assumed, just as is also the case when cell replication rates are not homogeneous, or depend on the cell state. Our analysis shows, for the first time, how ergodicity cannot be taken for granted in simple linear examples either. The latter holds even when cells are considered isolated and devoid of replication capabilities (cell-cycle arrested. We also show how a simple linear adaptation scheme displays fold-change detection properties, and how rupture of ergodicity prevails in scenarios where transitions between

  6. Methyl Antcinate A Suppresses the Population of Cancer Stem-Like Cells in MCF7 Human Breast Cancer Cell Line

    Directory of Open Access Journals (Sweden)

    Wen-Wei Chang

    2013-02-01

    Full Text Available Methyl antcinate A (MAA is an ergostane-type triterpenoid extracted from the fruiting bodies of Antrodia camphorate that has been reported to be a cytotoxic agent towards some types of cancer cells, such as oral cancer and liver cancer. Cancer stem cells (CSCs are a particular population within cancer cells which are responsible for tumor initiation, drug resistance and metastasis and targeting CSCs is an emerging area in cancer therapy. In this study, we examine the effect of MAA on cancer stem-like cells in the MCF7 human breast cancer cell line. Although MAA displayed very low cytotoxic effect towards MCF7 under normal culture conditions, it did show good inhibitory effects on the self-renewal capability which was examined by mammosphere culture including primary and secondary sphere. MAA also inhibited cell migration ability of MCF7 sphere cells. By western blot analysis, MAA was shown to suppress the expression of heat shock protein 27 and increase the expression of IkBα and p53. In conclusion, our data demonstrate that MAA has anti-CSC activity and is worthy of future development of potent anticancer agents.

  7. 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

  8. The IL-17A-producing CD8+ T-cell population in psoriatic lesional skin comprises mucosa-associated invariant T cells and conventional T cells.

    Science.gov (United States)

    Teunissen, Marcel B M; Yeremenko, Nataliya G; Baeten, Dominique L P; Chielie, Saskia; Spuls, Phyllis I; de Rie, Menno A; Lantz, Olivier; Res, Pieter C M

    2014-12-01

    IL-17A is pivotal in the etiology of psoriasis, and CD8(+) T cells with the ability to produce this cytokine (Tc17 cells) are over-represented in psoriatic lesions. Here we demonstrate that the frequency of Tc17 cells in peripheral blood of psoriasis patients correlated with the clinical severity of the disease. Analysis of cutaneous-associated lymphocyte antigen expression showed that the blood Tc17 population contains a significantly higher proportion of cells with skin-homing potential compared with the CD8(+) T-cell population lacking IL-17A/IL-22 expression. IL-17A-producing CD8(+) T cells in blood have previously been reported to belong mainly to the mucosa-associated invariant T-cell (MAIT cell) lineage characterized by TCR Vα7.2 chain, CD161, IL-18Rα, and multidrug transporter ABCB1 expression. We demonstrate the presence of CD8(+) MAIT cells in the dermis and epidermis of psoriatic plaques, as well as healthy skin; however, IL-17A-producing CD8(+) MAIT cells were predominantly found in psoriatic skin. Notably, we observed IL-17A production in a large proportion of psoriatic plaque-derived CD8(+) T cells devoid of MAIT cell characteristics, likely representing conventional CD8(+) T cells. In conclusion, we provide supporting evidence that implicates Tc17 cells in the pathogenesis of psoriasis and describe the presence of innate CD8(+) MAIT cells in psoriatic lesions as an alternative source of IL-17A. PMID:24945094

  9. Frequencies and specificities of red cell alloantibodies in the Southern Thai population

    OpenAIRE

    Charuporn Promwong; Santi Siammai; Sarunya Hassarin; Jarin Buakaew; Tanongsak Yeela; Patravee Soisangwan; David Roxby

    2013-01-01

    Context: Detailed reports of red cell alloantibody frequencies and specificities in the Thai population are limited. The aims of this study were to determine the specificity and compare the frequency of alloantibodies detected using column agglutination technology (CAT) and conventional tube techniques in blood donors and previously transfused patients. Settings and Design: We retrospectively reviewed antibody screening and identification records for two time periods: January-December 2006 du...

  10. Dynamic Aspects of the Structured Cell Population in a Swarming Colony of Proteus mirabilis

    OpenAIRE

    Matsuyama, Tohey; Takagi, Yuko; Nakagawa, Yoji; Itoh, Hiroto; Wakita, Junichi; Matsushita, Mitsugu

    2000-01-01

    Proteus mirabilis forms a concentric-ring colony by undergoing periodic swarming. A colony in the process of such synchronized expansion was examined for its internal population structure. In alternating phases, i.e., swarming (active migration) and consolidation (growth without colony perimeter expansion), phase-specific distribution of cells differing in length, in situ mobility, and migration ability on an agar medium were recognized. In the consolidation phase, the distribution of mobile ...

  11. Respiratory Muscle Force and Lung Volume Changes in a Population of Children with Sickle Cell Disease

    OpenAIRE

    Ong, Bruce A.; Caboot, Jason; Jawad, Abbas; McDonough, Joseph; Jackson, Tannoa; Arens, Raanan; Marcus, Carole L.; Smith-Whitley, Kim; Mason, Thornton B. A.; Ohene-Frempong, Kwaku; Allen, Julian L.

    2013-01-01

    Sickle cell disease (SCD) is a disorder known to impact the respiratory system. We sought to identify respiratory muscle force and lung volume relationships in a paediatric SCD population. Thirty-four SCD-SS subjects underwent pulmonary function testing. Height, weight, age, and gender-adjusted percent predicted maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) values were compared to spirometry and lung volumes. Statistical analyses were performed using Pearson’s corre...

  12. Resolved Photon Processes

    OpenAIRE

    Godbole, RM

    1998-01-01

    After giving a very brief introduction to the resolved photon processes, I will summarise the latest experimental information from HERA, on resolved photon contribution to large pt jet production as well as to direct photon production. I will point out the interesting role that resolved photon processes can play in increasing our understanding of the dynamics of the Quarkonium production. I will then discuss the newer information on the parton content of virtual photons as well as the kt dist...

  13. HCMV spread and cell tropism are determined by distinct virus populations.

    Directory of Open Access Journals (Sweden)

    Laura Scrivano

    Full Text Available Human cytomegalovirus (HCMV can infect many different cell types in vivo. Two gH/gL complexes are used for entry into cells. gH/gL/pUL(128,130,131A shows no selectivity for its host cell, whereas formation of a gH/gL/gO complex only restricts the tropism mainly to fibroblasts. Here, we describe that depending on the cell type in which virus replication takes place, virus carrying the gH/gL/pUL(128,130,131A complex is either released or retained cell-associated. We observed that virus spread in fibroblast cultures was predominantly supernatant-driven, whereas spread in endothelial cell (EC cultures was predominantly focal. This was due to properties of virus released from fibroblasts and EC. Fibroblasts released virus which could infect both fibroblasts and EC. In contrast, EC released virus which readily infected fibroblasts, but was barely able to infect EC. The EC infection capacities of virus released from fibroblasts or EC correlated with respectively high or low amounts of gH/gL/pUL(128,130,131A in virus particles. Moreover, we found that focal spread in EC cultures could be attributed to EC-tropic virus tightly associated with EC and not released into the supernatant. Preincubation of fibroblast-derived virus progeny with EC or beads coated with pUL131A-specific antibodies depleted the fraction that could infect EC, and left a fraction that could predominantly infect fibroblasts. These data strongly suggest that HCMV progeny is composed of distinct virus populations. EC specifically retain the EC-tropic population, whereas fibroblasts release EC-tropic and non EC-tropic virus. Our findings offer completely new views on how HCMV spread may be controlled by its host cells.

  14. Dendritic cell populations in patients with self-reported food hypersensitivity

    Directory of Open Access Journals (Sweden)

    Lied GA

    2011-05-01

    Full Text Available Gülen A Lied1,3,4,*, Petra Vogelsang2,*, Arnold Berstad1,4, Silke Appel2 1Institute of Medicine, 2Broegelmann Research Laboratory, The Gade Institute, University of Bergen, Norway; 3Division of Gastroenterology, Department of Medicine; 4Section of Clinical Allergology, Department of Occupational Medicine, Haukeland University Hospital, Bergen, Norway *These authors contributed equally to this workAbstract: Self-reported hypersensitivity to food is a common condition and many of these patients have indications of intestinal immune activation. Dendritic cells (DCs are recognized as the most potent antigen-presenting cells involved in both initiating immune responses and maintaining tolerance. The aims of this study were to evaluate the DC populations with their phenotype and T cell stimulatory capacity in patients with food hypersensitivity and to study its relationship with atopic disease. Blood samples from 10 patients with self-reported food hypersensitivity, divided into atopic and nonatopic subgroups, and 10 gender- and age-matched healthy controls were analyzed by flow cytometry using the Miltenyi Blood Dendritic cells kit. Monocyte-derived DCs (moDCs were evaluated concerning their phenotype and T cell stimulatory capacity. DC populations and cell surface markers were not significantly different between patients and healthy controls, but moDCs from atopic patients expressed significantly more CD38 compared to moDCs from nonatopic patients. Moreover, lipopolysaccharide stimulated moDCs from atopic patients produced significantly more interleukin-10 compared to nonatopic patients. CD38 expression was correlated to total serum immunoglobulin E levels. These findings support the notion of immune activation in some patients with self-reported food hypersensitivity. They need to be confirmed in a larger cohort.Keywords: food hypersensitivity, atopy, dendritic cells, CD38

  15. Distinct and conserved prominin-1/CD133-positive retinal cell populations identified across species.

    Directory of Open Access Journals (Sweden)

    József Jászai

    Full Text Available Besides being a marker of various somatic stem cells in mammals, prominin-1 (CD133 plays a role in maintaining the photoreceptor integrity since mutations in the PROM1 gene are linked with retinal degeneration. In spite of that, little information is available regarding its distribution in eyes of non-mammalian vertebrates endowed with high regenerative abilities. To address this subject, prominin-1 cognates were isolated from axolotl, zebrafish and chicken, and their retinal compartmentalization was investigated and compared to that of their mammalian orthologue. Interestingly, prominin-1 transcripts--except for the axolotl--were not strictly restricted to the outer nuclear layer (i.e., photoreceptor cells, but they also marked distinct subdivisions of the inner nuclear layer (INL. In zebrafish, where the prominin-1 gene is duplicated (i.e., prominin-1a and prominin-1b, a differential expression was noted for both paralogues within the INL being localized either to its vitreal or scleral subdivision, respectively. Interestingly, expression of prominin-1a within the former domain coincided with Pax-6-positive cells that are known to act as progenitors upon injury-induced retino-neurogenesis. A similar, but minute population of prominin-1-positive cells located at the vitreal side of the INL was also detected in developing and adult mice. In chicken, however, prominin-1-positive cells appeared to be aligned along the scleral side of the INL reminiscent of zebrafish prominin-1b. Taken together our data indicate that in addition to conserved expression of prominin-1 in photoreceptors, significant prominin-1-expressing non-photoreceptor retinal cell populations are present in the vertebrate eye that might represent potential sources of stem/progenitor cells for regenerative therapies.

  16. Epitope specific T-cell responses against influenza A in a healthy population.

    Science.gov (United States)

    Savic, Miloje; Dembinski, Jennifer L; Kim, Yohan; Tunheim, Gro; Cox, Rebecca J; Oftung, Fredrik; Peters, Bjoern; Mjaaland, Siri

    2016-02-01

    Pre-existing human CD4(+) and CD8(+) T-cell-mediated immunity may be a useful correlate of protection against severe influenza disease. Identification and evaluation of common epitopes recognized by T cells with broad cross-reactivity is therefore important to guide universal influenza vaccine development, and to monitor immunological preparedness against pandemics. We have retrieved an optimal combination of MHC class I and class II restricted epitopes from the Immune Epitope Database (www.iedb.org), by defining a fitness score function depending on prevalence, sequence conservancy and HLA super-type coverage. Optimized libraries of CD4(+) and CD8(+) T-cell epitopes were selected from influenza antigens commonly present in seasonal and pandemic influenza strains from 1934 to 2009. These epitope pools were used to characterize human T-cell responses in healthy donors using interferon-γ ELISPOT assays. Upon stimulation, significant CD4(+) and CD8(+) T-cell responses were induced, primarily recognizing epitopes from the conserved viral core proteins. Furthermore, the CD4(+) and CD8(+) T cells were phenotypically characterized regarding functionality, cytotoxic potential and memory phenotype using flow cytometry. Optimized sets of T-cell peptide epitopes may be a useful tool to monitor the efficacy of clinical trials, the immune status of a population to predict immunological preparedness against pandemics, as well as being candidates for universal influenza vaccines. PMID:26489873

  17. I Want More and Better Cells! – An Outreach Project about Stem Cells and Its Impact on the General Population

    Science.gov (United States)

    Varela Amaral, Sara; Forte, Teresa; Ramalho-Santos, João; Girão da Cruz, M. Teresa

    2015-01-01

    Although science and technology impact every aspect of modern societies, there is still an extensive gap between science and society, which impairs the full exercise of citizenship. In the particular case of biomedical research increased investment should be accompanied by parallel efforts in terms of public information and engagement. We have carried out a project involving the production and evaluation of educational contents focused on stem cells - illustrated newspaper chronicles, radio interviews, a comic book, and animated videos - and monitored their impact on the Portuguese population. The study of the outreach materials in a heterogeneous sample of the population suggests that they are valuable tools to disseminate scientific messages, and that this is especially true for the comic-book format. Furthermore, the data showed that clear and stimulating outreach materials, that are able to teach new concepts and to promote critical thinking, increase engagement in science at different levels, depending on the depth of the concepts involved. Additionally, these materials can influence political, social and personal attitudes toward science. These results, together with the importance attributed to scientific research in stem cells by the population sampled, validates the diffusion of such materials as a significant contribution towards an overall public understanding and engagement in contemporary science, and this strategy should thus be considered in future projects. Regardless, stringent quality control must be implemented in order to efficiently communicate accurate scientific developments, and the public stimulated in terms of finding additional sources of reliable information. PMID:26222053

  18. I Want More and Better Cells! - An Outreach Project about Stem Cells and Its Impact on the General Population.

    Science.gov (United States)

    Varela Amaral, Sara; Forte, Teresa; Ramalho-Santos, João; Girão da Cruz, M Teresa

    2015-01-01

    Although science and technology impact every aspect of modern societies, there is still an extensive gap between science and society, which impairs the full exercise of citizenship. In the particular case of biomedical research increased investment should be accompanied by parallel efforts in terms of public information and engagement. We have carried out a project involving the production and evaluation of educational contents focused on stem cells - illustrated newspaper chronicles, radio interviews, a comic book, and animated videos - and monitored their impact on the Portuguese population. The study of the outreach materials in a heterogeneous sample of the population suggests that they are valuable tools to disseminate scientific messages, and that this is especially true for the comic-book format. Furthermore, the data showed that clear and stimulating outreach materials, that are able to teach new concepts and to promote critical thinking, increase engagement in science at different levels, depending on the depth of the concepts involved. Additionally, these materials can influence political, social and personal attitudes toward science. These results, together with the importance attributed to scientific research in stem cells by the population sampled, validates the diffusion of such materials as a significant contribution towards an overall public understanding and engagement in contemporary science, and this strategy should thus be considered in future projects. Regardless, stringent quality control must be implemented in order to efficiently communicate accurate scientific developments, and the public stimulated in terms of finding additional sources of reliable information. PMID:26222053

  19. I Want More and Better Cells! - An Outreach Project about Stem Cells and Its Impact on the General Population.

    Directory of Open Access Journals (Sweden)

    Sara Varela Amaral

    Full Text Available Although science and technology impact every aspect of modern societies, there is still an extensive gap between science and society, which impairs the full exercise of citizenship. In the particular case of biomedical research increased investment should be accompanied by parallel efforts in terms of public information and engagement. We have carried out a project involving the production and evaluation of educational contents focused on stem cells - illustrated newspaper chronicles, radio interviews, a comic book, and animated videos - and monitored their impact on the Portuguese population. The study of the outreach materials in a heterogeneous sample of the population suggests that they are valuable tools to disseminate scientific messages, and that this is especially true for the comic-book format. Furthermore, the data showed that clear and stimulating outreach materials, that are able to teach new concepts and to promote critical thinking, increase engagement in science at different levels, depending on the depth of the concepts involved. Additionally, these materials can influence political, social and personal attitudes toward science. These results, together with the importance attributed to scientific research in stem cells by the population sampled, validates the diffusion of such materials as a significant contribution towards an overall public understanding and engagement in contemporary science, and this strategy should thus be considered in future projects. Regardless, stringent quality control must be implemented in order to efficiently communicate accurate scientific developments, and the public stimulated in terms of finding additional sources of reliable information.

  20. Characterization of Cs vapor cell coated with octadecyltrichlorosilane using coherent population trapping spectroscopy

    CERN Document Server

    Hafiz, Moustafa Abdel; Chutani, Ravinder; Passilly, Nicolas; Gorecki, Christophe; Guérandel, Stéphane; de Clercq, Emeric; Boudot, Rodolphe

    2015-01-01

    We report the realization and characterization using coherent population trapping (CPT) spectroscopy of an octadecyltrichlorosilane (OTS)-coated centimeter-scale Cs vapor cell. The dual-structure of the resonance lineshape, with presence of a narrow structure line at the top of a Doppler-broadened structure, is clearly observed. The linewidth of the narrow resonance is compared to the linewidth of an evacuated Cs cell and of a buffer gas Cs cell of similar size. The Cs-OTS adsorption energy is measured to be (0.42 $\\pm$ 0.03) eV, leading to a clock frequency shift rate of $2.7\\times10^{-9}/$K in fractional unit. A hyperfine population lifetime, $T_1$, and a microwave coherence lifetime, $T_2$, of 1.6 and 0.5 ms are reported, corresponding to about 37 and 12 useful bounces, respectively. Atomic-motion induced Ramsey narrowing of dark resonances is observed in Cs-OTS cells by reducing the optical beam diameter. Ramsey CPT fringes are detected using a pulsed CPT interrogation scheme. Potential applications of th...

  1. Role of resident CNS cell populations in HTLV-1-associated neuroinflammatory disease.

    Science.gov (United States)

    Lepoutre, Veronique; Jain, Pooja; Quann, Kevin; Wigdahl, Brian; Khan, Zafar K

    2009-01-01

    Human T cell leukemia virus type 1 (HTLV-1), the first human retrovirus discovered, is the etiologic agent for a number of disorders; the two most common pathologies include adult T cell leukemia (ATL) and a progressive demyelinating neuroinflammatory disease, HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The neurologic dysfunction associated with HAM/TSP is a result of viral intrusion into the central nervous system (CNS) and the generation of a hyperstimulated host response within the peripheral and central nervous system that includes expanded populations of CD4+ and CD8+ T cells and proinflammatory cytokines/chemokines in the cerebrospinal fluid (CSF). This robust, yet detrimental immune response likely contributes to the death of myelin producing oligodendrocytes and degeneration of neuronal axons. The mechanisms of neurological degeneration in HAM/TSP have yet to be fully delineated in vivo and may involve the immunogenic properties of the HTLV-1 transactivator protein Tax. This comprehensive review characterizes the available knowledge to date concerning the effects of HTLV-1 on CNS resident cell populations with emphasis on both viral and host factors contributing to the genesis of HAM/TSP. PMID:19273122

  2. Emodin As an Effective Agent in Targeting Cancer Stem-Like Side Population Cells of Gallbladder Carcinoma

    OpenAIRE

    Li, Xin-xing; Dong, Ying; Wang, Wei; Wang, Hao-lu; Chen, Yu-ying; Shi, Gui-ying; Yi, Jing; Wang, Jian

    2012-01-01

    Side population (SP) cells are previously identified from bone marrow based on their capacity to efflux of the fluorescent dye Hoechst 33342. Recent studies demonstrate that SP cells isolated from various cancer cell lines and primary tumors possess stem-cell-like properties. Thus, targeting tumor SP cells may provide new strategies for treatment in clinic. We previously showed that 1,3,8-trihydroxy-6-methylanthraquinone (emodin), a reactive oxygen species (ROS) generator, enhanced sensitivit...

  3. Mapping enteroendocrine cell populations in transgenic mice reveals an unexpected degree of complexity in cellular differentiation within the gastrointestinal tract

    OpenAIRE

    1990-01-01

    The gastrointestinal tract is lined with a monolayer of cells that undergo perpetual and rapid renewal. Four principal, terminally differentiated cell types populate the monolayer, enterocytes, goblet cells, Paneth cells, and enteroendocrine cells. This epithelium exhibits complex patterns of regional differentiation, both from crypt- to-villus and from duodenum-to-colon. The "liver" fatty acid binding protein (L-FABP) gene represents a useful model for analyzing the molecular basis for intes...

  4. Individualized leukemia cell-population profiles in common B-cell acute lymphoblastic leukemia patients

    OpenAIRE

    Xian-Ming Mo; Hong Xu; Ting-Ting Zeng; Neng-Gang Jiang; Yong-Qian Jia; Jing-Tao Dong; Jian-Hua Yu; Wen-Tong Meng

    2013-01-01

    Immunophenotype is critical for diagnosing common B-cell acute lymphoblastic leukemia (common ALL) and detecting minimal residual disease. We developed a protocol to explore the immunophenotypic profiles of common ALL based on the expression levels of the antigens associated with B lymphoid development, including IL-7R alpha (CD127), cytoplasmic CD79a (cCD79a), CD19, VpreB (CD179a), and sIgM, which are successive and essential for progression of B cells along their developmental pathway. Anal...

  5. Isolation and characterization of human trophoblast side-population (SP cells in primary villous cytotrophoblasts and HTR-8/SVneo cell line.

    Directory of Open Access Journals (Sweden)

    Tomoka Takao

    Full Text Available Recently, numerous studies have identified that immature cell populations including stem cells and progenitor cells can be found among "side-population" (SP cells. Although SP cells isolated from some adult tissues have been reported elsewhere, isolation and characterization of human trophoblast SP remained to be reported. In this study, HTR-8/SVneo cells and human primary villous cytotrophoblasts (vCTBs were stained with Hoechst 33342 and SP and non-SP (NSP fractions were isolated using a cell sorter. A small population of SP cells was identified in HTR-8/SVneo cells and in vCTBs. SP cells expressed several vCTB-specific markers and failed to express syncytiotrophoblast (STB or extravillous cytotrophopblast (EVT-specific differentiation markers. SP cells formed colonies and proliferated on mouse embryonic fibroblast (MEF feeder cells or in MEF conditioned medium supplemented with heparin/FGF2, and they also showed long-term repopulating property. SP cells could differentiate into both STB and EVT cell lineages and expressed several differentiation markers. Microarray analysis revealed that IL7R and IL1R2 were exclusively expressed in SP cells and not in NSP cells. vCTB cells sorted as positive for both IL7R and IL1R2 failed to express trophoblast differentiation markers and spontaneously differentiated into both STB and EVT in basal medium. These features shown by the SP cells suggested that IL7R and IL1R2 are available as markers to detect the SP cells and that vCTB progenitor cells and trophoblast stem cells were involved in the SP cell population.

  6. Role of cell cycle on the cellular uptake and dilution of nanoparticles in a cell population

    NARCIS (Netherlands)

    Kim, Jong Ah; Åberg, Christoffer; Salvati, Anna; Dawson, Kenneth A

    2012-01-01

    Nanoparticles are considered a primary vehicle for targeted therapies because they can pass biological barriers and enter and distribute within cells by energy-dependent pathways(1-3). So far, most studies have shown that nanoparticle properties, such as size(4-6) and surface(7,8), can influence how

  7. A simple add-on microfluidic appliance for accurately sorting small populations of cells with high fidelity

    International Nuclear Information System (INIS)

    Current advances in single cell sequencing, gene expression and proteomics require the isolation of single cells, frequently from a very small source population. In this work we describe the design and characterization of a manually operated microfluidic cell sorter that (1) can accurately sort single or small groups of cells from very small cell populations with minimal losses, (2) that is easy to operate and that can be used in any laboratory that has a basic fluorescent microscope and syringe pump, (3) that can be assembled within minutes, (4) that can sort cells in very short time (minutes) with minimum cell stress, (5) that is cheap and reusable. This microfluidic sorter is made from hard plastic material (PMMA) into which microchannels are directly milled with hydraulic diameter of 70 µm. Inlet and outlet reservoirs are drilled through the chip. Sorting occurs through hydrodynamic switching ensuring low hydrodynamic shear stresses, which were modeled and experimentally confirmed to be below the cell damage threshold. Manually operated, the maximum sorting frequencies were approximately 10 cells min−1. Experiments verified that cell sorting operations could be achieved in as little as 15 min, including the assembly and testing of the sorter. In only one out of ten sorting experiments the sorted cells were contaminated with another cell type. This microfluidic cell sorter represents an important capability for protocols requiring fast isolation of single cells from small number of rare cell populations. (technical note)

  8. Temporal dynamics of distinct CA1 cell populations during unconscious state induced by ketamine.

    Directory of Open Access Journals (Sweden)

    Hui Kuang

    Full Text Available Ketamine is a widely used dissociative anesthetic which can induce some psychotic-like symptoms and memory deficits in some patients during the post-operative period. To understand its effects on neural population dynamics in the brain, we employed large-scale in vivo ensemble recording techniques to monitor the activity patterns of simultaneously recorded hippocampal CA1 pyramidal cells and various interneurons during several conscious and unconscious states such as awake rest, running, slow wave sleep, and ketamine-induced anesthesia. Our analyses reveal that ketamine induces distinct oscillatory dynamics not only in pyramidal cells but also in at least seven different types of CA1 interneurons including putative basket cells, chandelier cells, bistratified cells, and O-LM cells. These emergent unique oscillatory dynamics may very well reflect the intrinsic temporal relationships within the CA1 circuit. It is conceivable that systematic characterization of network dynamics may eventually lead to better understanding of how ketamine induces unconsciousness and consequently alters the conscious mind.

  9. Osteoclast cytomorphometry demonstrates an abnormal population in B cell malignancies but not in multiple myeloma.

    Science.gov (United States)

    Chappard, D; Rossi, J F; Bataille, R; Alexandre, C

    1991-01-01

    Increased bone resorption in the vicinity of myeloma cells is mediated by local stimulating factors. Other malignancies of the B cell lineage are also able to produce resorbing factors responsible for increased bone resorption. We have studied three groups of subjects: 10 patients with overt multiple myeloma, 10 patients with a B cell malignancy, and 10 healthy human subjects as controls. Patients were studied at the time of diagnosis and had a transiliac bone biopsy. Osteoclasts were evident on histological sections by their acid phosphatase activity. A software was developed on an automatic image analyzer (Leitz TAS+) for measuring the maximal Feret's diameter (Oc.Le) of each osteoclast (corresponding to the osteoclast length). The histogram of Oc.Le frequency distribution was supplied in each group. In myeloma patients, the Oc.Le frequency distribution was similar to that in normal subjects and showed the histogram to be asymetric with a positive skew (maximum peak at 20-25 microns). With a graphical analysis, this distribution was shown to follow a lognormal distribution corresponding to a homogeneous osteoclast population. In other B cell malignancies, Oc.Le displayed a bimodal distribution with a peak at 20-25 microns and a lower peak at 10-15 microns. The graphical analysis showed that small (mononucleated?) osteoclasts are present in B cell malignancies with normal osteoclasts. This might reflect the secretion of different soluble factors by malignant cells of the B lymphocyte lineage. PMID:1706639

  10. Single cell genomics indicates horizontal gene transfer and viral infections in a deep subsurface Firmicutes population.

    Science.gov (United States)

    Labonté, Jessica M; Field, Erin K; Lau, Maggie; Chivian, Dylan; Van Heerden, Esta; Wommack, K Eric; Kieft, Thomas L; Onstott, Tullis C; Stepanauskas, Ramunas

    2015-01-01

    A major fraction of Earth's prokaryotic biomass dwells in the deep subsurface, where cellular abundances per volume of sample are lower, metabolism is slower, and generation times are longer than those in surface terrestrial and marine environments. How these conditions impact biotic interactions and evolutionary processes is largely unknown. Here we employed single cell genomics to analyze cell-to-cell genome content variability and signatures of horizontal gene transfer (HGT) and viral infections in five cells of Candidatus Desulforudis audaxviator, which were collected from a 3 km-deep fracture water in the 2.9 Ga-old Witwatersrand Basin of South Africa. Between 0 and 32% of genes recovered from single cells were not present in the original, metagenomic assembly of Desulforudis, which was obtained from a neighboring subsurface fracture. We found a transposable prophage, a retron, multiple clustered regularly interspaced short palindromic repeats (CRISPRs) and restriction-modification systems, and an unusually high frequency of transposases in the analyzed single cell genomes. This indicates that recombination, HGT and viral infections are prevalent evolutionary events in the studied population of microorganisms inhabiting a highly stable deep subsurface environment. PMID:25954269

  11. Single cell genomics indicates horizontal gene transfer and viral infections in a deep subsurface Firmicutes population

    Directory of Open Access Journals (Sweden)

    Jessica eLabonté

    2015-04-01

    Full Text Available A major fraction of Earth's prokaryotic biomass dwells in the deep subsurface, where cellular abundances per volume of sample are lower, metabolism is slower, and generation times are longer than those in surface terrestrial and marine environments. How these conditions impact biotic interactions and evolutionary processes is largely unknown. Here we employed single cell genomics to analyze cell-to-cell genome content variability and signatures of horizontal gene transfer (HGT and viral infections in five cells of Candidatus Desulforudis audaxviator, which were collected from a three km-deep fracture water in the 2.9 Ga-old Witwatersrand Basin of South Africa. Between 0 and 32 % of genes recovered from single cells were not present in the original, metagenomic assembly of Desulforudis, which was obtained from a neighboring subsurface fracture. We found a transposable prophage, a retron, multiple clustered regularly interspaced short palindromic repeats (CRISPRs and restriction-modification systems, and an unusually high frequency of transposases in the analyzed single cell genomes. This indicates that recombination, HGT and viral infections are prevalent evolutionary events in the studied population of microorganisms inhabiting a highly stable deep subsurface environment.

  12. Rate control in yeast protein synthesis at the population and single-cell levels.

    Science.gov (United States)

    Dacheux, Estelle; Firczuk, Helena; McCarthy, John E G

    2015-12-01

    Yeast commits approximately 76% of its energy budget to protein synthesis and the efficiency and control of this process are accordingly critical to organism growth and fitness. We now have detailed genetic, biochemical and biophysical knowledge of the components of the eukaryotic translation machinery. However, these kinds of information do not, in themselves, give us a satisfactory picture of how the overall system is controlled. This is where quantitative system analysis can enable a step-change in our understanding of biological resource management and how this relates to cell physiology and evolution. An important aspect of this more system-oriented approach to translational control is the inherent heterogeneity of cell populations that is generated by gene expression noise. In this short review, we address the fact that, although the vast majority of our knowledge of the translation machinery is based on experimental analysis of samples that each contain hundreds of millions of cells, in reality every cell is unique in terms of its composition and control properties. We have entered a new era in which research into the heterogeneity of cell systems promises to provide answers to many (previously unanswerable) questions about cell physiology and evolution. PMID:26614671

  13. Intrahepatic natural killer T cell populations are increased in human hepatic steatosis

    Institute of Scientific and Technical Information of China (English)

    Michael Adler; Sarah Taylor; Kamalu Okebugwu; Herman Yee; Christine Fielding; George Fielding; Michael Poles

    2011-01-01

    AIM: To determine if natural killer T cell (NKT) populations are affected in nonalcoholic fatty liver disease(NAFLD).METHODS: Patients undergoing bariatric surgery underwent liver biopsy and blood sampling during surgery.The biopsy was assessed for steatosis and immunocyte infiltration. Intrahepatic lymphocytes (IHLs) were isolated from the remainder of the liver biopsy,and peripheral blood mononuclear cells (PBMCs) were isolated from the blood. Expression of surface proteins on both IHLs and PBMCs were quantified using flow cytometry.RESULTS: Twenty-seven subjects participated in this study. Subjects with moderate or severe steatosis had a higher percentage of intrahepatic CD3+/CD56+ NKT cells (38.6%) than did patients with mild steatosis(24.1%, P = 0.05) or those without steatosis (21.5%, P= 0.03). Patients with moderate to severe steatosis alsohad a higher percentage of NKT cells in the blood (12.3%) as compared to patients with mild steatosis (2.5% P =0.02) and those without steatosis (5.1%, P = 0.05).CONCLUSION: NKT cells are significantly increased in the liver and blood of patients with moderate to severe steatosis and support the role of NKT cells in NAFLD.

  14. The impact of early- and late-onset preeclampsia on umbilical cord blood cell populations.

    Science.gov (United States)

    Herzog, Emilie M; Eggink, Alex J; van der Zee, Marten; Lagendijk, Jacqueline; Willemsen, Sten P; de Jonge, Robert; Steegers, Eric A P; Steegers-Theunissen, Regine P M

    2016-08-01

    Pregnancies complicated by preeclampsia (PE) are characterised by an enhanced maternal and fetal inflammatory response with increased numbers of leukocytes in maternal peripheral blood. The impact of PE on newborn umbilical cord blood cell (UCBC) populations however, has been scarcely studied. We hypothesise that PE deranges fetal haematopoiesis and subsequently UCBC populations. Therefore, the objective of this study was to investigate newborn umbilical cord blood cell populations in early- (EOPE) and late-onset PE (LOPE). A secondary cohort analysis in The Rotterdam Periconceptional Cohort was conducted comprising 23 PE cases, including 11 EOPE and 12 LOPE, and 195 controls, including 153 uncomplicated and 23 fetal growth restriction- and 19 preterm birth complicated controls. UCBC counts and differentials were quantified by flow cytometry and analysed as main outcome measures. Multivariable regression analysis revealed associations of EOPE with decreased leucocyte- (monocytes, neutrophils, eosinophils, immature granulocytes) and thrombocyte counts and increased NRBC counts (all p<0.05). EOPE remained associated with neutrophil- (β-0.92, 95%CI -1.27,-0.57, p<0.001) and NRBC counts (β1.11, 95%CI 0.27,1.95, p=0.010) after adjustment for gestational age and birth weight. LOPE did not reveal any significant association. We conclude that derangements of fetal haematopoiesis, in particular of neutrophil- and NRBC counts, are associated with EOPE only, with a potential impact for future health of the offspring. This heterogeneity in UCBC should be considered as confounder in epigenetic association studies examining EOPE. PMID:27239988

  15. Molecular Genetic Characterization of β-Thalassemia and Sickle Cell Syndrome in the Albanian Population.

    Science.gov (United States)

    Babameto-Laku, A; Mitre, A; Berisha, S; Mokini, V; Roko, D

    2011-06-01

    β-Thalassemia (β-thal) is a major public health problem in Albania as it is in many Mediterranean countries. We determined the different β-thal alleles that are present in the Albanian population by using the temporal temperature gradient electrophoresis (TTGE) method because of its high throughput, cost-effectiveness, sensitivity and simplicity. DNA from blood of 68 patients with β-thal, 26 with sickle cell anemia or sickle cell β-thal, 54 parents of these patients and 14 heterozygotes related to these families. We found the IVS-I-110 (G>A), codon 39 (C>T), IVS-I-6 (T>C), IVS-I-1 (G>A) and codon 44 (-C) mutations that accounted for nearly 90% of the β-thal alleles. Their frequencies were similar to those found in other studies in the Albanian population. This method has permitted the detection of heterozygotes for β-thal in this population and offers a prenatal diagnosis with a probability of 90% accuracy. PMID:24052702

  16. Secrecy from Resolvability

    CERN Document Server

    Bloch, Matthieu R

    2011-01-01

    We investigate an approach to physical-layer security based on the premise that the coding mechanism for secrecy over noisy channels is fundamentally tied to the notion of resolvability. Instead of considering capacity-based constructions, which associate to each message a sub-code whose rate approaches the capacity of the eavesdropper's channel, we consider resolvability-based constructions, which associate to each message a sub-code whose rate is beyond the resolvability of the eavesdropper's channel. We provide evidence that resolvability is a more powerful and perhaps more fundamental coding mechanism for secrecy by developing results that hold for strong secrecy metrics and arbitrary channels. Specifically, we show that, at least for binary symmetric wiretap channels, random capacity-based constructions fail to approach the strong secrecy capacity while resolvability-based constructions achieve it. We then obtain the secrecy-capacity region of arbitrary broadcast channels with confidential messages and a...

  17. Defining cell populations with single-cell gene expression profiling: correlations and identification of astrocyte subpopulations

    Czech Academy of Sciences Publication Activity Database

    Stahlberg, A.; Andersson, D.; Aurelius, J.; Faiz, M.; Pekna, M.; Kubista, Mikael; Pekny, M.

    2011-01-01

    Roč. 39, č. 4 (2011). ISSN 0305-1048 R&D Projects: GA AV ČR IAA500970904; GA ČR GAP303/10/1338 Institutional research plan: CEZ:AV0Z50520701 Keywords : EMBRYONIC STEM-CELLS * REAL-TIME PCR * MESSENGER-RNA Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 8.026, year: 2011

  18. Plasmacytoid dendritic cells and neutrophils : underestimated cell populations during the onset of atherosclerosis

    OpenAIRE

    Döring, Yvonne

    2011-01-01

    This study focuses on the understanding of the pathophysiological role of neutrophils and plasmacytoid dendritic cells in atherosclerosis. Atherosclerosis is now agreed to be a chronic inflammatory disease of the vessel wall driven by intense immunological activity, of both, innate and adaptive immunity. Whereas monocytes/macrophages are of paramount importance, polymorphonuclear neutrophilic leukocytes (PMN) have recently also been implicated in lesion formation. Given the expansion of these...

  19. Characterization of distinct mesenchymal-like cell populations from human skeletal muscle in situ and in vitro

    International Nuclear Information System (INIS)

    Human skeletal muscle is an essential source of various cellular progenitors with potential therapeutic perspectives. We first used extracellular markers to identify in situ the main cell types located in a satellite position or in the endomysium of the skeletal muscle. Immunohistology revealed labeling of cells by markers of mesenchymal (CD13, CD29, CD44, CD47, CD49, CD62, CD73, CD90, CD105, CD146, and CD15 in this study), myogenic (CD56), angiogenic (CD31, CD34, CD106, CD146), hematopoietic (CD10, CD15, CD34) lineages. We then analysed cell phenotypes and fates in short- and long-term cultures of dissociated muscle biopsies in a proliferation medium favouring the expansion of myogenic cells. While CD56+ cells grew rapidly, a population of CD15+ cells emerged, partly from CD56+ cells, and became individualized. Both populations expressed mesenchymal markers similar to that harboured by human bone marrow-derived mesenchymal stem cells. In differentiation media, both CD56+ and CD15+ cells shared osteogenic and chondrogenic abilities, while CD56+ cells presented a myogenic capacity and CD15+ cells presented an adipogenic capacity. An important proportion of cells expressed the CD34 antigen in situ and immediately after muscle dissociation. However, CD34 antigen did not persist in culture and this initial population gave rise to adipogenic cells. These results underline the diversity of human muscle cells, and the shared or restricted commitment abilities of the main lineages under defined conditions.

  20. Maintaining RNA integrity in a homogeneous population of mammary epithelial cells isolated by Laser Capture Microdissection

    Directory of Open Access Journals (Sweden)

    Helbling Jean-Christophe

    2010-12-01

    Full Text Available Abstract Background Laser-capture microdissection (LCM that enables the isolation of specific cell populations from complex tissues under morphological control is increasingly used for subsequent gene expression studies in cell biology by methods such as real-time quantitative PCR (qPCR, microarrays and most recently by RNA-sequencing. Challenges are i to select precisely and efficiently cells of interest and ii to maintain RNA integrity. The mammary gland which is a complex and heterogeneous tissue, consists of multiple cell types, changing in relative proportion during its development and thus hampering gene expression profiling comparison on whole tissue between physiological stages. During lactation, mammary epithelial cells (MEC are predominant. However several other cell types, including myoepithelial (MMC and immune cells are present, making it difficult to precisely determine the specificity of gene expression to the cell type of origin. In this work, an optimized reliable procedure for producing RNA from alveolar epithelial cells isolated from frozen histological sections of lactating goat, sheep and cow mammary glands using an infrared-laser based Arcturus Veritas LCM (Applied Biosystems® system has been developed. The following steps of the microdissection workflow: cryosectioning, staining, dehydration and harvesting of microdissected cells have been carefully considered and designed to ensure cell capture efficiency without compromising RNA integrity. Results The best results were obtained when staining 8 μm-thick sections with Cresyl violet® (Ambion, Applied Biosystems® and capturing microdissected cells during less than 2 hours before RNA extraction. In addition, particular attention was paid to animal preparation before biopsies or slaughtering (milking and freezing of tissue blocks which were embedded in a cryoprotective compound before being immersed in isopentane. The amount of RNA thus obtained from ca.150 to 250 acini

  1. Time-resolved studies

    International Nuclear Information System (INIS)

    When new or more powerful probes become available that offer both shorter data-collection times and the opportunity to apply innovative approaches to established techniques, it is natural that investigators consider the feasibility of exploring the kinetics of time-evolving systems. This stimulating area of research not only can lead to insights into the metastable or excited states that a system may populate on its way to a ground state, but can also lead to a better understanding of that final state. Synchrotron radiation, with its unique properties, offers just such a tool to extend X-ray measurements from the static to the time-resolved regime. The most straight-forward application of synchrotron radiation to the study of transient phenomena is directly through the possibility of decreased data-collection times via the enormous increase in flux over that of a laboratory X-ray system. Even further increases in intensity can be obtained through the use of novel X-ray optical devices. Widebandpass monochromators, e.g., that utilize the continuous spectral distribution of synchrotron radiation, can increase flux on the sample several orders of magnitude over conventional X-ray optical systems thereby allowing a further shortening of the data-collection time. Another approach that uses the continuous spectral nature of synchrotron radiation to decrease data-collection times is the open-quote parallel data collectionclose quotes method. Using this technique, intensities as a function of X-ray energy are recorded simultaneously for all energies rather than sequentially recording data at each energy, allowing for a dramatic decrease in the data-collection time

  2. Derivation and characterization of human embryonic stem cell lines from the Chinese population

    Institute of Scientific and Technical Information of China (English)

    Zhao Wu; Huimin Dai; Lei Qian; Qing Tian; Lei Xiao; Xiaojun Tan; Hui Li; Lingjun Rao; Lixiazi He; Lei Bao; Jing Liao; Chun Cui; Zhenyu Zuo; Qiao Li

    2011-01-01

    Human embryonic stem cells (hESCs) can self-renew indefinitely and differentiate into all cell types in the human body. Therefore, they are valuable in regenerative medicine, human developmental biology and drug discovery. A number of hESC lines have been derived from the Chinese population,but limited of them are available for research purposes. Here we report the derivation and characterization of two hESC lines derived from human blastocysts of Chinese origin. These hESCs express alkaline phosphatase and hESC-specific markers, including Oct4, Nanog, SSEA-3, SSEA-4,TRA-1-60 and TRA-1-81. They also have high levels of telomerase activity and normal karyotypes. These cells can form embryoid body in vitro and can be differentiated into all three germ layers in vivo by teratoma formation. The newly established hESCs will be distributed for research purposes.The availability of hESC lines from the Chinese population will facilitate studies on the differences in hESCs from different ethnic groups.

  3. Response of Listeria monocytogenes to disinfection stress at the single-cell and population levels as monitored by intracellular pH measurements and viable-cell counts

    DEFF Research Database (Denmark)

    Kastbjerg, Vicky Gaedt; Nielsen, Dennis S.; Arneborg, Nils;

    2009-01-01

    bacterium. In situ analyses of Listeria monocytogenes single cells were performed during exposure to different concentrations of the disinfectant Incimaxx DES to study a possible population subdivision. Bacterial survival was quantified with plate counting and disinfection stress at the single-cell level by.......05). The protective effect of NaCl was reflected by viable-cell counts at a higher concentration of Incimaxx (0.0031%), where the salt-grown population survived better than the population grown without NaCl (P <0.05). NaCl protected attached cells through drying but not during disinfection. This study......Listeria monocytogenes has a remarkable ability to survive and persist in food production environments. The purpose of the present study was to determine if cells in a population of L. monocytogenes differ in sensitivity to disinfection agents as this could be a factor explaining persistence of the...

  4. 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

  5. Distribution of CD4 lymphocyte cells among apparently healthy HIV seropositive and seronegative populations

    Directory of Open Access Journals (Sweden)

    Abdulazeez A Abubakar

    2012-01-01

    Full Text Available Background: CD4 lymphocyte cells are often used as prognostic markers for monitoring the progression of immunosupression such as HIV infection. Aim: This study was conducted to assess the distribution of CD4 lymphocytes among apparently healthy human immunodeficiency virus (HIV seronegative and seropositive populations in a Nigerian state. Materials and Methods: A total of 1520 apparently healthy subjects aged 18-64 years, composed of 800 males and 720 females attending some selected health institutions in the state, participated in the study. Ten milliliters of blood was collected from each subject; 5 ml of this was used for HIV antibodies sero-typing while the remaining 5 ml was anticoagulated and used for CD4 lymphocytes level determination. Only samples tested positive both with Capillus and Determine HIV test kits were further differentiated into sero-types with a standard diagnostic HIV test kit. The CD4 lymphocyte levels of all the sample were determined; mean CD4 levels of 205.1±0.09 and 287.4±0.3 cells/μl were recorded among females seropositives and seronagatives respectively. Statistical analysis by the Student t-test showed a significant difference in the mean CD4 lymphocyte count by gender. Results: Findings showed a mean CD4 level of 311.7±1.2 cells/μl among seropositive males while 399.3±0.6 cells/μl was recorded among seronegatives (t=5.86. The study also recorded a CD4 lymphocyte range of 232-464 cells/μl among apparently healthy seronegative population in this locality. Conclusion: The findings showed a significantly higher mean CD4 lymphocyte count among adult male HIV seronegatives (χ2= 9.22 and seropositives (χ2=15.07 than their female counterparts. Further research work using the automation technique is suggested to confirm this new range for monitoring HIV subjects on antiretroviral therapy.

  6. A population balance equation model of aggregation dynamics in Taxus suspension cell cultures.

    Science.gov (United States)

    Kolewe, Martin E; Roberts, Susan C; Henson, Michael A

    2012-02-01

    The nature of plant cells to grow as multicellular aggregates in suspension culture has profound effects on bioprocess performance. Recent advances in the measurement of plant cell aggregate size allow for routine process monitoring of this property. We have exploited this capability to develop a conceptual model to describe changes in the aggregate size distribution that are observed over the course of a Taxus cell suspension batch culture. We utilized the population balance equation framework to describe plant cell aggregates as a particulate system, accounting for the relevant phenomenological processes underlying aggregation, such as growth and breakage. We compared model predictions to experimental data to select appropriate kernel functions, and found that larger aggregates had a higher breakage rate, biomass was partitioned asymmetrically following a breakage event, and aggregates grew exponentially. Our model was then validated against several datasets with different initial aggregate size distributions and was able to quantitatively predict changes in total biomass and mean aggregate size, as well as actual size distributions. We proposed a breakage mechanism where a fraction of biomass was lost upon each breakage event, and demonstrated that even though smaller aggregates have been shown to produce more paclitaxel, an optimum breakage rate was predicted for maximum paclitaxel accumulation. We believe this is the first model to use a segregated, corpuscular approach to describe changes in the size distribution of plant cell aggregates, and represents an important first step in the design of rational strategies to control aggregation and optimize process performance. PMID:21910121

  7. The stem cell population of the human colon crypt: analysis via methylation patterns.

    Directory of Open Access Journals (Sweden)

    Pierre Nicolas

    2007-03-01

    Full Text Available The analysis of methylation patterns is a promising approach to investigate the genealogy of cell populations in an organism. In a stem cell-niche scenario, sampled methylation patterns are the stochastic outcome of a complex interplay between niche structural features such as the number of stem cells within a niche and the niche succession time, the methylation/demethylation process, and the randomness due to sampling. As a consequence, methylation pattern studies can reveal niche characteristics but also require appropriate statistical methods. The analysis of methylation patterns sampled from colon crypts is a prototype of such a study. Previous analyses were based on forward simulation of the cell content of the whole crypt and subsequent comparisons between simulated and experimental data using a few statistics as a proxy to summarize the data. In this paper we develop a more powerful method to analyze these data based on coalescent modelling and Bayesian inference. Results support a scenario where the colon crypt is maintained by a high number of stem cells; the posterior indicates a number greater than eight and the posterior mode is between 15 and 20. The results also provide further evidence for synergistic effects in the methylation/demethylation process that could for the first time be quantitatively assessed through their long-term consequences such as the coexistence of hypermethylated and hypomethylated patterns in the same colon crypt.

  8. Coherent population trapping in small- and chip-scale 87Rb vapor cells with buffer gas

    Science.gov (United States)

    Ermak, S. V.; Semenov, V. V.; Petrenko, M. V.; Pyatyshev, E. N.

    2016-03-01

    The characteristics of coherent population trapping (CPT) signal were investigated in small-size glass vapor cells containing 87Rb and Ne buffer gas with narrow line-width laser pumping on D2 line. The parameters of CPT signals were measured using small-size vapor cells with Ne buffer gas pressure in the range of 200-400 Torr, cell temperature in the range of 65-120 ∘C and the values of laser pumping power of 30-400 μW/cm2. Optimal conditions, under which the minimal value of short-term instability of resonance line is achieved, were obtained in experiments. Orientation frequency shifts of CPT resonance using glass 87Rb vapor cells containing buffer gas and anti-relaxation coating were compared. CPT signals using vapor cells based on integrated technologies containing 87Rb in atmosphere of Ne were also investigated. The CPT signals with typical line widths of 2-3 kHz and signal-to-noise ratio of 1500 in 1 Hz bandwidth are observed, which allows one to provide relative frequency instability of 10-11 at 100 s.

  9. Programmable models of growth and mutation of cancer-cell populations

    CERN Document Server

    Bortolussi, Luca; 10.4204/EPTCS.67.4

    2011-01-01

    In this paper we propose a systematic approach to construct mathematical models describing populations of cancer-cells at different stages of disease development. The methodology we propose is based on stochastic Concurrent Constraint Programming, a flexible stochastic modelling language. The methodology is tested on (and partially motivated by) the study of prostate cancer. In particular, we prove how our method is suitable to systematically reconstruct different mathematical models of prostate cancer growth - together with interactions with different kinds of hormone therapy - at different levels of refinement.

  10. Investigating population dynamics of the Kumbh Mela through the lens of cell phone data

    CERN Document Server

    Onnela, Jukka-Pekka

    2015-01-01

    The Kumbh is a religious Hindu festival that has been celebrated for centuries. The 2013 Kumbh Mela, a grander form of the annual Kumbh, was purportedly the largest gathering of people in human history. Many of the participants carried cell phones, making it possible for us to use a data-driven approach to document this magnificent festival. We used Call Detail Records (CDRs) from participants attending the event, a total of 390 million records, to investigate its population dynamics. We report here on some of our preliminary findings.

  11. Zygomatic air cell defect: A panoramic radiographic study of a south Indian population

    International Nuclear Information System (INIS)

    To determine the prevalence, patterns of occurrence and variations of zygomatic air cell defects (ZACDs) using panoramic radiographs. Dental panoramic radiographs of 600 outpatients were examined to evaluate the variations and characteristics of ZACDs. ZACDs were identified in 15 subjects out of 600, giving an overall prevalence of 2.5%. Seven ZACDs were seen in males and eight in females. Among the 15 ZACDs, nine were unilateral and six were bilateral. The overall prevalence of ZACD is relatively low in south Indian population and careful radiographic evaluation is needed to detect these entities

  12. Ovarian Stimulation Affects the Population of Mouse Uterine NK Cells at Early Pregnancy

    OpenAIRE

    Parvin Dorfeshan; Mojdeh Salehnia; Seyed Mohammad Moazzeni

    2013-01-01

    The aim of this study was to determine the influence of ovarian stimulation on endometrial mouse NK cell population. For superovulation, the female adult NMRI mice were injected i.p. with 10 IU of the pregnant mare serum gonadotropin followed 48 h later by an i.p. injection of 10 IU human chorionic gonadotropin hormone. Ovarian stimulated and nonstimulated mice were mated with fertile male. The presence of vaginal plug proved natural pregnancy, and this day was considered as day one of pregna...

  13. Population-based estimates of the occurrence of multiple vs first primary basal cell carcinomas in 4 European regions

    NARCIS (Netherlands)

    E. de Vries (Esther); R. Micallef (R.); D.H. Brewster; J.H. Gibbs (James); S.C. Flohil (Sophie); O. Saksela (O.); R. Sankila (R.); A.D. Forrest (A.); M. Trakatelli (Myrto); J.W.W. Coebergh (Jan Willem); C.M. Proby (C.)

    2012-01-01

    textabstractObjective: To estimate the population-based incidence of first and multiple basal cell carcinomas (BCCs) throughout Europe. Design: The registry practices of 4 population-based cancer registries that routinely register BCC incidence were evaluated for inclusion of first and subsequent hi

  14. Antigen-Specific Cytotoxic T Lymphocytes can Target Chemoresistant Side-Population Tumor Cells in Hodgkin’s Lymphoma

    OpenAIRE

    Shafer, Jessica A.; Cruz, Conrad R.; Leen, Ann M; Ku, Stephanie; LU, AN; Rousseau, Alexandra; Heslop, Helen E.; Rooney, Cliona M; Bollard, Catherine M.; Foster, Aaron E.

    2010-01-01

    Side-population (SP) analysis has been used to identify progenitor cells from normal and malignant tissues as well as revealing tumor cells with increased resistance to radiation and chemotherapy. Despite enhanced chemoresistance, tumor SP cells may still express tumor associated antigens (TAA) which may render them susceptible to elimination by the immune system. In this study, we show that both Hodgkin’s lymphoma (HL) cell lines and primary HL tumor samples contain a distinct SP phenotype. ...

  15. Cardiac Repair With a Novel Population of Mesenchymal Stem Cells Resident in the Human Heart.

    Science.gov (United States)

    Zhang, Yuan; Sivakumaran, Priyadharshini; Newcomb, Andrew E; Hernandez, Damián; Harris, Nicole; Khanabdali, Ramin; Liu, Guei-Sheung; Kelly, Darren J; Pébay, Alice; Hewitt, Alex W; Boyle, Andrew; Harvey, Richard; Morrison, Wayne A; Elliott, David A; Dusting, Gregory J; Lim, Shiang Y

    2015-10-01

    Cardiac resident stem cells (CRSCs) hold much promise to treat heart disease but this remains a controversial field. Here, we describe a novel population of CRSCs, which are positive for W8B2 antigen and were obtained from adult human atrial appendages. W8B2(+) CRSCs exhibit a spindle-shaped morphology, are clonogenic and capable of self-renewal. W8B2(+) CRSCs show high expression of mesenchymal but not hematopoietic nor endothelial markers. W8B2(+) CRSCs expressed GATA4, HAND2, and TBX5, but not C-KIT, SCA-1, NKX2.5, PDGFRα, ISL1, or WT1. W8B2(+) CRSCs can differentiate into cardiovascular lineages and secrete a range of cytokines implicated in angiogenesis, chemotaxis, inflammation, extracellular matrix remodeling, cell growth, and survival. In vitro, conditioned medium collected from W8B2(+) CRSCs displayed prosurvival, proangiogenic, and promigratory effects on endothelial cells, superior to that of other adult stem cells tested, and additionally promoted survival and proliferation of neonatal rat cardiomyocytes. Intramyocardial transplantation of human W8B2(+) CRSCs into immunocompromised rats 1 week after myocardial infarction markedly improved cardiac function (∼40% improvement in ejection fraction) and reduced fibrotic scar tissue 4 weeks after infarction. Hearts treated with W8B2(+) CRSCs showed less adverse remodeling of the left ventricle, a greater number of proliferating cardiomyocytes (Ki67(+) cTnT(+) cells) in the remote region, higher myocardial vascular density, and greater infiltration of CD163(+) cells (a marker for M2 macrophages) into the border zone and scar regions. In summary, W8B2(+) CRSCs are distinct from currently known CRSCs found in human hearts, and as such may be an ideal cell source to repair myocardial damage after infarction. PMID:26184084

  16. Age-Related Changes in Population of Stromal Precursor Cells in Hematopoietic and Lymphoid Organs.

    Science.gov (United States)

    Gorskaya, Yulia F.; Latzinik, Natalia V.; Shuklina, Ekaterina U.; Nesterenko, Vladimir G.

    2000-07-01

    It is shown that the content of precursor cells of stromal tissue (CFC-F) in the hemopoietic and lymphoid organs of SAMP (rapidly-ageing mice) and SAMR mice (mice with a normal ageing rate) decreases as the animals grow older. However the decrease in the content of CFC-F in SAMP mice begins substantially earlier - in the age group of 9-11 months, while in the SAMR mice - only in the age group of 16-19 months. It was found that the age reduction of the number to an equal degree relates to the whole population of CFC-F, in particular both the fraction of weakly-linked CFC-F, which is isolated by means of mechanical disaggregation of the tissue, and the fraction which may only be isolated using trypsin. It is shown that the concentration of inducible osteogenic precursor cells (IOPC) in the spleen of guinea pigs does not change with age, but their content in that organ in old animals (2-3 years old) drops by two times. It was found that in elderly animals the mass of the ectopic osseous tissue, formed by the implantation of an osteoinductor (autologous epithelium of the urinary bladder) in a system open for entrance of cells, decreases by two times. After curettage of the medullary cavity of guinea pig tibia (i.e. under conditions of an increased demand for osteogenic cells) the mass of induced ectopic osseous tissue decreases by 4 times, which indicates to the possible functional relationship between the pool of determined and inducible osteogenic precursor cells. On the whole, the obtained data show that during ageing there is a reduction in the number of stromal precursor cells (CFC-F and IOPC), which form a specific microenvironment for hemopoietic and lymphoid organs, which is important to understand the role of these cells in the development of age pathologies, in particular senile osteoporosis. PMID:12687170

  17. Cauchy problem for multiscale conservation laws: Application to structured cell populations

    CERN Document Server

    Shang, Peipei

    2010-01-01

    In this paper, we study a vector conservation law that models the growth and selection of ovarian follicles. During each ovarian cycle, only a definite number of follicles ovulate, while the others undergo a degeneration process called atresia. This work is motivated by a multiscale mathematical model starting on the cellular scale, where ovulation or atresia result from a hormonally controlled selection process. A two-dimensional conservation law describes the age and maturity structuration of the follicular cell populations. The densities intersect through a coupled hyperbolic system between different follicles and cell phases, which results in a vector conservation law and coupling boundary conditions. The maturity velocity functions possess both a local and nonlocal character. We prove the existence and uniqueness of the weak solution to the Cauchy problem with bounded initial and boundary data.

  18. Deciphering DNA replication dynamics in eukaryotic cell populations in relation with their averaged chromatin conformations

    Science.gov (United States)

    Goldar, A.; Arneodo, A.; Audit, B.; Argoul, F.; Rappailles, A.; Guilbaud, G.; Petryk, N.; Kahli, M.; Hyrien, O.

    2016-03-01

    We propose a non-local model of DNA replication that takes into account the observed uncertainty on the position and time of replication initiation in eukaryote cell populations. By picturing replication initiation as a two-state system and considering all possible transition configurations, and by taking into account the chromatin’s fractal dimension, we derive an analytical expression for the rate of replication initiation. This model predicts with no free parameter the temporal profiles of initiation rate, replication fork density and fraction of replicated DNA, in quantitative agreement with corresponding experimental data from both S. cerevisiae and human cells and provides a quantitative estimate of initiation site redundancy. This study shows that, to a large extent, the program that regulates the dynamics of eukaryotic DNA replication is a collective phenomenon that emerges from the stochastic nature of replication origins initiation.

  19. Study of optoelectronic properties of thin film solar cell materials Cu2ZnSn(S,Se)4 using multiple correlative spatially-resolved spectroscopy techniques

    Science.gov (United States)

    Chen, Qiong

    Containing only earth abundant and environmental friendly elements, quaternary compounds Cu2ZnSnS4 (CZTS) and Cu2ZnSnSe 4 (CZTSe) are considered as promising absorber materials for thin film solar cells. The best record efficiency for this type of thin film solar cell is now 12.6%. As a promising photovoltaic (PV) material, the electrical and optical properties of CZTS(Se) have not been well studied. In this work, an effort has been made to understand the optoelectronic and structural properties, in particular the spatial variations, of CZTS(Se) materials and devices by correlating multiple spatially resolved characterization techniques with sub-micron resolution. Micro-Raman (micro-Raman) spectroscopy was used to analyze the chemistry compositions in CZTS(Se) film; Micro-Photoluminescence (micro-PL) was used to determine the band gap and possible defects. Micro-Laser-Beam-Induced-Current (micro-LBIC) was used to examine the photo-response of CZTS(Se) solar cell in different illumination conditions. Micro-reflectance was used to estimate the reflectance loss. And Micro-I-V measurement was used to compare important electrical parameters from CZTS(Se) solar cells with different device structure or absorber compositions. Scanning electron microscopy and atomic force microscopy were used to characterize the surface morphology. Successfully integrating and correlating these techniques was first demonstrated during the course of this work in our laboratory, and this level of integration and correlation has been rare in the field of PV research. This effort is significant not only for this particular project and also for a wide range of research topics. Applying this approach, in conjunction with high-temperature and high-excitation-power optical spectroscopy, we have been able to reveal the microscopic scale variations among samples and devices that appeared to be very similar from macroscopic material and device characterizations, and thus serve as a very powerful tool

  20. Transcriptional modulation in a leukocyte-depleted splenic cell population during prion disease.

    Science.gov (United States)

    Huzarewich, Rhiannon L C H; Medina, Sarah; Robertson, Catherine; Parchaliuk, Debra; Booth, Stephanie A

    2011-01-01

    Prion replication in the periphery precedes neuroinvasion in many experimental rodent scrapie models, and in natural sheep scrapie and chronic wasting disease (CWD) in cervids. Prions propagate in the germinal centers of secondary lymphoid organs and are strongly associated with follicular dendritic cells (FDC) and possibly circulating dendritic cells and macrophages. Given the importance of lymphoid organs in prion disease transmission and pathogenesis, gene expression studies may reveal host factors or biological pathways related to prion replication and accumulation. A procedure was developed to enrich for FDC, dendritic cells, and macrophages prior to the investigation of transcriptional alterations in murine splenic cells during prion pathogenesis. In total, 1753 transcripts exhibited fold changes greater than three (false discovery rates less than 2%) in this population isolated from spleens of prion-infected versus uninfected mice. The gene for the small leucine-rich proteoglycan decorin (DCN) was one of the genes most overexpressed in infected mice, and the splenic protein levels mirrored this in mice infected with scrapie as well as bovine spongiform encephalopathy (BSE) and variant Creutzfeldt-Jakob disease (vCJD). A number of groups of functionally related genes were also significantly decreased in infected spleens. These included genes related to iron metabolism and homeostasis, pathways that have also been implicated in prion pathogenesis in the brain. These gene expression alterations provide insights into the molecular mechanisms underlying prion disease pathogenesis and may serve as a pool of potential surrogate markers for the early detection and diagnosis of some prion diseases. PMID:22043911

  1. Unexpected diversity in populations of the many-celled magnetotactic prokaryote.

    Science.gov (United States)

    Simmons, Sheri L; Edwards, Katrina J

    2007-01-01

    The many-celled magnetotactic prokaryote (MMP) is an uncultivated, highly motile aggregate of 10-30 cells containing numerous chains of greigite (Fe(3)S(4)) magnetosomes. It is unique to marine environments and is abundant in slightly sulfidic sediments of the Little Sippewissett salt marsh (Falmouth, MA). We sequenced 16s rDNA genes from a natural population of MMP and found five lineages separated by at least 5% sequence divergence. Fluorescent in situ hybridization probes for three of these lineages showed significant variation in their relative abundances across a seasonal cycle in marsh productivity. The MMP should therefore be considered a separate genus in the delta-proteobacteria rather than a single species as previously thought. All cells in each aggregate express identical SSU rRNAs, suggesting that the aggregates are composed of a single MMP phylotype. This observation supports a model of the MMP as comprised of clonal cells which reproduce by binary fission of the aggregate. PMID:17227425

  2. Effect of ionizing radiation on development process of T-cell population lymphocytes in Chernobyl children

    International Nuclear Information System (INIS)

    The aim of preliminary study was determined development process status of T-cell population lymphocytes in Ukrainian children after 22 years from Chernobyl accident for next feasibility study. Material and Method: 150 participants aged 6 to 16 years are included in three groups: Group I (n=65), 30 to 60 km from center accident at zone 3th, Group II (n=65) 60 to 90 km from same location at zone 4th and control group (n=20) from Kiev, 100 km from same location. Peripheral blood leukocytes from buffy coats were analyzed for T-Iymphocytes population such as T-Iymphocytes (CD3), T-helper (CD4) and T-cytotoxic (CD8) by roseting method using erythrocytes that conjugated with monoclonal antibody against CD3, CD4, and CD8 receptors; then CD4/CD8 ratio were calculated. Results: Percentage of CD3 and CD4 in groups II and I decreased significantly in compared to control group at P<0.001. Percent of CD8 decreased significantly in group I compared to control group at P <0.001. CD4/CD8 ratio decreased significantly in-group I comparison to control group at P=0.02. Leucocytes count in groups II and I have not changed significantly in comparison to control group (P=0.09,P=0.4) but in group II, it was significantly different in comparison to group I at P <0.008. Conclusion: Our data show that after 2 decade of Chernobyl accident, ionizing radiation may have affected the developmental processes of T-cell population.

  3. Down-regulation of the Fetal Stem Cell Factor SOX17 by H33342: A MECHANISM RESPONSIBLE FOR DIFFERENTIAL GENE EXPRESSION IN BREAST CANCER SIDE POPULATION CELLS

    OpenAIRE

    Christgen, Matthias; Geffers, Robert; Ballmaier, Matthias; Christgen, Henriette; Poczkaj, Janette; Krech, Till; Kreipe, Hans; Lehmann, Ulrich

    2009-01-01

    Human solid tumors contain rare cancer side population (SP) cells, which expel the fluorescent dye Hoechst 33342 (H33342) and display cancer stem cell characteristics. Transcriptional profiling of cancer SP cells isolated by H33342 fluorescence analysis is a newly emerging approach to discover cancer stem cell markers and aberrant differentiation pathways. Using Affymetrix expression microarrays and quantitative reverse transcription-PCR, we investigated differential gene expression between S...

  4. Response of Listeria monocytogenes to Disinfection Stress at the Single-Cell and Population Levels as Monitored by Intracellular pH Measurements and Viable-Cell Counts▿

    OpenAIRE

    Kastbjerg, Vicky G.; Nielsen, Dennis S.; Arneborg, Nils; Gram, Lone

    2009-01-01

    Listeria monocytogenes has a remarkable ability to survive and persist in food production environments. The purpose of the present study was to determine if cells in a population of L. monocytogenes differ in sensitivity to disinfection agents as this could be a factor explaining persistence of the bacterium. In situ analyses of Listeria monocytogenes single cells were performed during exposure to different concentrations of the disinfectant Incimaxx DES to study a possible population subdivi...

  5. Muscle-derived stem cells isolated as non-adherent population give rise to cardiac, skeletal muscle and neural lineages

    International Nuclear Information System (INIS)

    Stem cells with the ability to differentiate in specialized cell types can be extracted from a wide array of adult tissues including skeletal muscle. Here we have analyzed a population of cells isolated from skeletal muscle on the basis of their poor adherence on uncoated or collagen-coated dishes that show multi-lineage differentiation in vitro. When analysed under proliferative conditions, these cells express stem cell surface markers Sca-1 (65%) and Bcrp-1 (80%) but also MyoD (15%), Neuronal β III-tubulin (25%), GFAP (30%) or Nkx2.5 (1%). Although capable of growing as non-attached spheres for months, when given an appropriate matrix, these cells adhere giving rise to skeletal muscle, neuronal and cardiac muscle cell lineages. A similar cell population could not be isolated from either bone marrow or cardiac tissue suggesting their specificity to skeletal muscle. When injected into damaged muscle, these non-adherent muscle-derived cells are retrieved expressing Pax7, in a sublaminar position characterizing satellite cells and participate in forming new myofibers. These data show that a non-adherent stem cell population can be specifically isolated and expanded from skeletal muscle and upon attachment to a matrix spontaneously differentiate into muscle, cardiac and neuronal lineages in vitro. Although competing with resident satellite cells, these cells are shown to significantly contribute to repair of injured muscle in vivo supporting that a similar muscle-derived non-adherent cell population from human muscle may be useful in treatment of neuromuscular disorders

  6. 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

  7. 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.

  8. Hepatitis B virus reactivation and hepatitis in diffuse large B-cell lymphoma patients with resolved hepatitis B receiving rituximab-containing chemotherapy:risk factors and survival

    Institute of Scientific and Technical Information of China (English)

    Kai-Lin Chen; De-Hui Zou; Li-Yang Hu; Michael Lucas Wirian; Qing-Qing Cai; Jie Chen; Hui-Lan Rao; Ying Guo; Hui-Qiang Huang; Liang Zhang; Jian-Yong Shao; Tong-Yu Lin; Wen-Qi Jiang

    2015-01-01

    Introduction:Hepatitis B virus (HBV) reactivation has been reported in B-cel lymphoma patients with resolved hepatitis B (hepatitis B surface antigen [HBsAg]-negative and hepatitis B core antibody [HBcAb]-positive). This study aimed to assess HBV reactivation and hepatitis occurrence in diffuse large B-cel lymphoma (DLBCL) patients with resolved hepatitis B receiving rituximab-containing chemotherapy compared with HBsAg-negative/HBcAb-negative patients to identify risk factors for HBV reactivation and hepatitis occurrence and to analyze whether HBV reactivation and hepatitis affect the survival of DLBCL patients with resolved hepatitis B. Methods:We reviewed the clinical data of 278 patients with DLBCL treated with rituximab-containing therapy between January 2004 and May 2008 at Sun Yat-sen University Cancer Center, China. Predictive factors for HBV reactivation, hepatitis development, and survival were examined by univariate analysis using the chi-square or Fisher’s exact test and by multivariate analysis using the Cox regression model. Results:Among the 278 patients, 165 were HBsAg-negative. Among these 165 patients, 6 (10.9%) of 55 HBcAb-positive (resolved HBV infection) patients experienced HBV reactivation compared with none (0%) of 110 HBcAb-negative patients (P=0.001). Patients with resolved hepatitis B had a higher hepatitis occurrence rate than HBsAg-negative/HBcAb-negative patients (21.8%vs. 8.2%, P=0.013). HBcAb positivity and elevated baseline alanine aminotransferase (ALT) levels were independent risk factors for hepatitis. Among the 55 patients with resolved hepatitis B, patients with elevated baseline serum ALT or aspartate aminotransferase (AST) levels were more likely to develop hepatitis than those with normal serum ALT or AST levels (P=0.037, P=0.005, respectively). An elevated baseline AST level was an independent risk factor for hepatitis in these patients. Six patients with HBV reactivation recovered after immediate antiviral therapy, and

  9. CD133 expression is not selective for tumor initiating or radioresistant cell populations in the CRC line HCT-116

    International Nuclear Information System (INIS)

    The hypothesis of certain subpopulations of cancer cells with stem-cell like characteristics that might be responsible for treatment resistance and recurrence of disease is still challenging and under quite controversial discussion. In most studies, surrogate cell surface antigens such as the 92-110 kDa transmembrane glycoprotein CD133 (human Prominin-1) were labeled to isolate particular small cancer cell populations for studying their tumorigenic potential. In colorectal carcinomas (CRC) for example, a small CD133 positive (CD133+) cell population has recently been described to be enriched for tumor-initiating/cancer stem cells (TIC/CSC) as compared to the CD133 negative (CD133) population. Furthermore, it was documented that the CD133+ subpopulation could exclusively be maintained in culture as spheres under serum-free conditions. Addition of serum resulted in cell differentiation, growth in 2-D and downregulation of CD133 expression. This would imply that established colorectal cancer (CRC) cell lines that have been grown under adherent, serum-supplemented conditions for years should be devoid of CD133+ cells and TIC/CSC, respectively, which seems contradictory to the finding that many CRC lines produce tumors in nude mice models. In order to gain insight into this paradox, we studied the expression of CD133 in numerous established CRC lines under standard culture conditions and chose one particular cell line based on its expression pattern to study the behavior of CD133+ / CD133- subpopulations

  10. Behavior of a metabolic cycling population at the single cell level as visualized by fluorescent gene expression reporters.

    Directory of Open Access Journals (Sweden)

    Sunil Laxman

    Full Text Available BACKGROUND: During continuous growth in specific chemostat cultures, budding yeast undergo robust oscillations in oxygen consumption that are accompanied by highly periodic changes in transcript abundance of a majority of genes, in a phenomenon called the Yeast Metabolic Cycle (YMC. This study uses fluorescent reporters of genes specific to different YMC phases in order to visualize this phenomenon and understand the temporal regulation of gene expression at the level of individual cells within the cycling population. METHODOLOGY: Fluorescent gene expression reporters for different phases of the YMC were constructed and stably integrated into the yeast genome. Subsequently, these reporter-expressing yeast were used to visualize YMC dynamics at the individual cell level in cultures grown in a chemostat or in a microfluidics platform under varying glucose concentrations, using fluorescence microscopy and quantitative Western blots. CONCLUSIONS: The behavior of single cells within a metabolic cycling population was visualized using phase-specific fluorescent reporters. The reporters largely recapitulated genome-specified mRNA expression profiles. A significant fraction of the cell population appeared to exhibit basal expression of the reporters, supporting the hypothesis that there are at least two distinct subpopulations of cells within the cycling population. Although approximately half of the cycling population initiated cell division in each permissive window of the YMC, metabolic synchrony of the population was maintained. Using a microfluidics platform we observed that low glucose concentrations appear to be necessary for metabolic cycling. Lastly, we propose that there is a temporal window in the oxidative growth phase of the YMC where the cycling population segregates into at least two subpopulations, one which will enter the cell cycle and one which does not.

  11. Estimation of the target stem-cell population size in chronic myeloid leukemogenesis

    International Nuclear Information System (INIS)

    Estimation of the number of hematopoietic stem cells capable of causing chronic myeloid leukemia (CML) is relevant to the development of biologically based risk models of radiation-induced CML. Through a comparison of the age structure of CML incidence data from the Surveillance, Epidemiology, and End Results (SEER) Program and the age structure of chromosomal translocations found in healthy subjects, the number of CML target stem cells is estimated for individuals above 20 years of age. The estimation involves three steps. First, CML incidence among adults is fit to an exponentially increasing function of age. Next, assuming a relatively short waiting time distribution between BCR-ABL induction and the appearance of CML, an exponential age function with rate constants fixed to the values found for CML is fitted to the translocation data. Finally, assuming that translocations are equally likely to occur between any two points in the genome, the parameter estimates found in the first two steps are used to estimate the number of target stem cells for CML. The population-averaged estimates of this number are found to be 1.86 x 108 for men and 1.21 x 108 for women; the 95% confidence intervals of these estimates are (1.34 x 108, 2.50 x 108) and (0.84 x 108, 1.83 x 108), respectively. (orig.)

  12. High-speed elasticity-specific nonlinear Brillouin imaging/sensing via time-resolved optical (BISTRO) measurements

    Science.gov (United States)

    Meng, Zhaokai; Ballman, Charles W.; Petrov, Georgi I.; Yakovlev, Vladislav V.

    2016-03-01

    Viscoelastic properties of living cells are often directly related to the cell types and their physiological conditions. Unfortunately, all the currently existing methods for analysis of viscoelastic properties of cells, such as micropipette aspiration, atomic force microscopy and optical tweezers are intrinsically slow, limiting their applicability to study large population of cells, which are often needed for either fundamental or clinical studies. In this report, by incorporating the concept of impulsive stimulated Brillouin scattering (ISBS), we report a Brillouin Imaging and Sensing system via Time-Resolved Optical (BISTRO) measurements. We will prove the principle of the BISTRO system by presenting example microscopic measurements and flow/cell cytometry results [1].

  13. Comprehensive Protocols to Isolate, Characterize, and Culture pure-population of Multi-potent Stem Cell from Mouse Epidermis

    OpenAIRE

    sprotocols

    2015-01-01

    A pure-population of keratinocyte stem cell culture is required for applications such as transgenic-mouse-stem cell preparation, stem cell therapy, tissue engineering, iPS technology, besides study of growth & differentiation, toxicology, and related mechanistic aspects. Protocols available in literature do not conform to desired purity and better yield in short span of time, culture-condition for rapid growth, and characterization methods (1-24). We report here the improved, albeit compr...

  14. Kinetics of Infection and Effects on Placental Cell Populations in a Murine Model of Chlamydia psittaci-Induced Abortion

    OpenAIRE

    Buendía, Antonio J.; Sánchez, Joaquín; Martínez, María C.; Cámara, Paulina; Navarro, Jose A.; Rodolakis, Annie; Salinas, Jesus

    1998-01-01

    The anatomical progression of chlamydial infection was studied in different areas of the placenta, using a mouse model and two inoculation times: early pregnancy (day 7, group A) and midpregnancy (day 11, group B). The first population cells affected were decidual cells and neutrophils located just at the limits of the maternal and fetal placenta. The following invaded area was the layer of giant cells. Complete colonization of the maternal placenta occurred after day 15 of pregnancy independ...

  15. Awakened by Cellular Stress: Isolation and Characterization of a Novel Population of Pluripotent Stem Cells Derived from Human Adipose Tissue

    OpenAIRE

    Saleh Heneidi; Simerman, Ariel A; Erica Keller; Prapti Singh; Xinmin Li; Daniel A Dumesic; Gregorio Chazenbalk

    2013-01-01

    Advances in stem cell therapy face major clinical limitations, particularly challenged by low rates of post-transplant cell survival. Hostile host factors of the engraftment microenvironment such as hypoxia, nutrition deprivation, pro-inflammatory cytokines, and reactive oxygen species can each contribute to unwanted differentiation or apoptosis. In this report, we describe the isolation and characterization of a new population of adipose tissue (AT) derived pluripotent stem cells, termed Mul...

  16. Identification of multipotent mesenchymal stromal cells in the reactive stroma of a prostate cancer xenograft by side population analysis

    International Nuclear Information System (INIS)

    Cancer stem cells are a distinct cellular population that is believed to be responsible for tumor initiation and maintenance. Recent data suggest that solid tumors also contain another type of stem cells, the mesenchymal stem cells or multipotent mesenchymal stromal cells (MSCs), which contribute to the formation of tumor-associated stroma. The Hoechst 33342 efflux assay has proved useful to identify a rare cellular fraction, named Side Population (SP), enriched in cells with stem-like properties. Using this assay, we identified SP cells in a prostate cancer xenograft containing human prostate cancer cells and mouse stromal cells. The SP isolation, subculture and sequential sorting allowed the generation of single-cell-derived clones of murine origin that were recognized as MSC by their morphology, plastic adherence, proliferative potential, adipogenic and osteogenic differentiation ability and immunophenotype (CD45-, CD81+ and Sca-1+). We also demonstrated that SP clonal cells secrete transforming growth factor β1 (TGF-β1) and that their inhibition reduces proliferation and accelerates differentiation. These results reveal the existence of SP cells in the stroma of a cancer xenograft, and provide evidence supporting their MSC nature and the role of TGF-β1 in maintaining their proliferation and undifferentiated status. Our data also reveal the usefulness of the SP assay to identify and isolate MSC cells from carcinomas.

  17. Characterization of distinct mesenchymal-like cell populations from human skeletal muscle in situ and in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Lecourt, Severine, E-mail: severine.lecourt@sls.aphp.fr [UPMC/AIM UMR S 974, Groupe Hospitalier Pitie-Salpetriere, Paris (France); INSERM U974, Groupe Hospitalier Pitie-Salpetriere, Paris (France); CNRS UMR 7215, Groupe Hospitalier Pitie-Salpetriere, Paris (France); Laboratoire de Therapie Cellulaire, Hopital Saint Louis, Paris (France); Marolleau, Jean-Pierre, E-mail: Marolleau.Jean-Pierre@chu-amiens.fr [Laboratoire de Therapie Cellulaire, Hopital Saint Louis, Paris (France); CHU Amiens Hopital Sud, Service d' Hematologie Clinique, UPJV, Amiens (France); Fromigue, Olivia, E-mail: olivia.fromigue@larib.inserm.fr [INSERM U606, Universite Paris 07, Hopital Lariboisiere, Paris (France); Vauchez, Karine, E-mail: k.vauchez@institut-myologie.org [UPMC/AIM UMR S 974, Groupe Hospitalier Pitie-Salpetriere, Paris (France); INSERM U974, Groupe Hospitalier Pitie-Salpetriere, Paris (France); CNRS UMR 7215, Groupe Hospitalier Pitie-Salpetriere, Paris (France); Genzyme S.A.S., Saint-Germain en Laye (France); Andriamanalijaona, Rina, E-mail: rinandria@yahoo.fr [Laboratoire de Biochimie des Tissus Conjonctifs, Faculte de Medecine, Caen (France); Ternaux, Brigitte, E-mail: brigitte.ternaux@orange.fr [Laboratoire de Therapie Cellulaire, Hopital Saint Louis, Paris (France); Lacassagne, Marie-Noelle, E-mail: mnlacassagne@free.fr [Laboratoire de Therapie Cellulaire, Hopital Saint Louis, Paris (France); Robert, Isabelle, E-mail: isa-robert@hotmail.fr [Laboratoire de Therapie Cellulaire, Hopital Saint Louis, Paris (France); Boumediene, Karim, E-mail: karim.boumediene@unicaen.fr [Laboratoire de Biochimie des Tissus Conjonctifs, Faculte de Medecine, Caen (France); Chereau, Frederic, E-mail: fchereau@pervasistx.com [Myosix S.A., Saint-Germain en Laye (France); Marie, Pierre, E-mail: pierre.marie@larib.inserm.fr [INSERM U606, Universite Paris 07, Hopital Lariboisiere, Paris (France); and others

    2010-09-10

    Human skeletal muscle is an essential source of various cellular progenitors with potential therapeutic perspectives. We first used extracellular markers to identify in situ the main cell types located in a satellite position or in the endomysium of the skeletal muscle. Immunohistology revealed labeling of cells by markers of mesenchymal (CD13, CD29, CD44, CD47, CD49, CD62, CD73, CD90, CD105, CD146, and CD15 in this study), myogenic (CD56), angiogenic (CD31, CD34, CD106, CD146), hematopoietic (CD10, CD15, CD34) lineages. We then analysed cell phenotypes and fates in short- and long-term cultures of dissociated muscle biopsies in a proliferation medium favouring the expansion of myogenic cells. While CD56{sup +} cells grew rapidly, a population of CD15{sup +} cells emerged, partly from CD56{sup +} cells, and became individualized. Both populations expressed mesenchymal markers similar to that harboured by human bone marrow-derived mesenchymal stem cells. In differentiation media, both CD56{sup +} and CD15{sup +} cells shared osteogenic and chondrogenic abilities, while CD56{sup +} cells presented a myogenic capacity and CD15{sup +} cells presented an adipogenic capacity. An important proportion of cells expressed the CD34 antigen in situ and immediately after muscle dissociation. However, CD34 antigen did not persist in culture and this initial population gave rise to adipogenic cells. These results underline the diversity of human muscle cells, and the shared or restricted commitment abilities of the main lineages under defined conditions.

  18. Relationship of Somatic Cell Count with Milk Yield and Composition in Chinese Holstein Population

    Institute of Scientific and Technical Information of China (English)

    GUO Jia-zhong; LIU Xiao-lin; XU A-juan; XIA Zhi

    2010-01-01

    The objective of this study was to analyze the relationship of somatic cell count(SCC)with milk yield,fat and protein percentage,fat and protein yield using analysis of variance and correlation analysis in Chinese Holstein population.The10 524 test-day records of 568 Chinese Holstein Cattle were obtained from 2 commercial herds in Xi'an region of China during February 2002 to March 2009.Milk yield,fat percentage,fat and protein yield initially increased and then dropped down with parity,whereas protein percentage decreased and SCC increased.Analysis of variance showed highly significant effects of different subclasses SCC on milk yield and composition(P0.05).The results of the present study first time provide the relevant base-line data for assessing milk production at Xi'an region of China.

  19. High-field-strength MR imaging evaluation of stroke in the sickle cell population

    International Nuclear Information System (INIS)

    Stroke is a well-known but understudied complication of sickle cell disease (SCD). The authors have studied the incidence and patterns of clinical and subclinical stroke in 73 SCD patients. The patients underwent formal neurologic evaluation and high-field strength, heavily T2-weighted axial cranial MR imaging (TR = 3,500 msec, TE = 80 msec). Eighteen of the 73 patients had clinical strokes, acute, nonconvulsive neurologic events with lateralizing neurological signs lasting 1 hour. All but two of these patients demonstrated focal MR imaging abnormalities. The remaining 55 patients were controls. Ten percent of them had focal MR imaging abnormalities suggesting subclinical stroke. A feature of the SCD population is the preponderance of strokes in the distal field and watershed distribution

  20. Doped Overoxidized Polypyrrole Microelectrodes as Sensors for the Detection of Dopamine Released from Cell Populations

    DEFF Research Database (Denmark)

    Sasso, Luigi; Heiskanen, Arto; Diazzi, Francesco;

    2013-01-01

    A surface modification of interdigitated gold microelectrodes (IDEs) with a doped polypyrrole (PPy) film for detection of dopamine released from populations of differentiated PC12 cells is presented. A thin PPy layer was potentiostatically electropolymerized from an 10 aqueous pyrrole solution onto...... electrode surfaces. The conducting polymer film was doped during electropolymerization by introducing counter ions in the monomer solution. Several counter ions were tested and the resulting electrode modifications were characterized electrochemically to find the optimal dopant that increases sensitivity in...... dopamine detection. Overoxidation of the PPy films was shown to contribute to a significant enhancement in sensitivity to dopamine. The changes caused by overoxidation in the electrochemical behavior and electrode morphology were investigated using cyclic voltammetry and SEM as well as AFM, respectively...

  1. Caesium cell coherent population trapping clock: main effects affecting the frequency stability

    International Nuclear Information System (INIS)

    Atomic clocks using coherent population trapping (CPT) allow to improve performances of vapour cell conventional microwave clocks, or else to miniaturize them thanks to of a full optical interrogation. In this paper, we describe a prototype developed at LNE-SYRTE. It combines two original techniques: an excitation scheme with two linearly and orthogonally polarized beams, and a Ramsey interrogation. This enables the observation of narrow resonances with a good signal-to-noise ratio. A few major effects influencing the frequency stability are addressed; they are the effect of the buffer gas, of the magnetic field, of the laser power, and finally the effect of the local oscillator noise or Dick effect. The measured frequency stability is 7x10-13 at 1 s and 2x10-14 at 2000 s. (authors)

  2. Characterizing passive coherent population trapping resonance in a cesium vapor cell filled with neon buffer gas

    International Nuclear Information System (INIS)

    We present a pair of phase-locked lasers with a 9.2-GHz frequency difference through the injection locking of a master laser to the RF-modulation sideband of a slave diode laser. Using this laser system, a coherent population trapping (CPT) signal with a typical linewidth of ∼ 182 Hz is obtained in a cesium vapor cell filled with 30 Torr (4 kPa) of neon as the buffer gas. We investigate the influence of the partial pressure of the neon buffer gas on the CPT linewidth, amplitude, and frequency shift. The results may offer some references for CPT atomic clocks and CPT atomic magnetometers. (atomic and molecular physics)

  3. A differential equation with state-dependent delay from cell population biology

    Science.gov (United States)

    Getto, Philipp; Waurick, Marcus

    2016-04-01

    We analyze a differential equation, describing the maturation of a stem cell population, with a state-dependent delay, which is implicitly defined via the solution of an ODE. We elaborate smoothness conditions for the model ingredients, in particular vital rates, that guarantee the existence of a local semiflow and allow to specify the linear variational equation. The proofs are based on theoretical results of Hartung et al. combined with implicit function arguments in infinite dimensions. Moreover we elaborate a criterion for global existence for differential equations with state-dependent delay. To prove the result we adapt a theorem by Hale and Lunel to the C1-topology and use a result on metric spaces from Diekmann et al.

  4. Transcriptional profiling at whole population and single cell levels reveals somatosensory neuron molecular diversity.

    Science.gov (United States)

    Chiu, Isaac M; Barrett, Lee B; Williams, Erika K; Strochlic, David E; Lee, Seungkyu; Weyer, Andy D; Lou, Shan; Bryman, Gregory S; Roberson, David P; Ghasemlou, Nader; Piccoli, Cara; Ahat, Ezgi; Wang, Victor; Cobos, Enrique J; Stucky, Cheryl L; Ma, Qiufu; Liberles, Stephen D; Woolf, Clifford J

    2014-01-01

    The somatosensory nervous system is critical for the organism's ability to respond to mechanical, thermal, and nociceptive stimuli. Somatosensory neurons are functionally and anatomically diverse but their molecular profiles are not well-defined. Here, we used transcriptional profiling to analyze the detailed molecular signatures of dorsal root ganglion (DRG) sensory neurons. We used two mouse reporter lines and surface IB4 labeling to purify three major non-overlapping classes of neurons: 1) IB4(+)SNS-Cre/TdTomato(+), 2) IB4(-)SNS-Cre/TdTomato(+), and 3) Parv-Cre/TdTomato(+) cells, encompassing the majority of nociceptive, pruriceptive, and proprioceptive neurons. These neurons displayed distinct expression patterns of ion channels, transcription factors, and GPCRs. Highly parallel qRT-PCR analysis of 334 single neurons selected by membership of the three populations demonstrated further diversity, with unbiased clustering analysis identifying six distinct subgroups. These data significantly increase our knowledge of the molecular identities of known DRG populations and uncover potentially novel subsets, revealing the complexity and diversity of those neurons underlying somatosensation. PMID:25525749

  5. A model combining cell physiology and population genetics to explain Escherichia coli laboratory evolution

    Directory of Open Access Journals (Sweden)

    Acerenza Luis

    2001-12-01

    Full Text Available Abstract Background Laboratory experiments under controlled conditions during thousands of generations are useful tools to assess the processes underlying bacterial evolution. As a result of these experiments, the way in which the traits change in time is obtained. Under these conditions, the bacteria E. coli shows a parallel increase in cell volume and fitness. Results To explain this pattern it is required to consider organismic and population contributions. For this purpose we incorporate relevant information concerning bacterial structure, composition and transformations in a minimal modular model. In the short time scale, the model reproduces the physiological responses of the traits to changes in nutrient concentration. The decay of unused catabolic functions, found experimentally, is introduced in the model using simple population genetics. The resulting curves representing the evolution of volume and fitness in time are in good agreement with those obtained experimentally. Conclusions This study draws attention on physiology when studying evolution. Moreover, minimal modular models appear to be an adequate strategy to unite these barely related disciplines of biology.

  6. Interferon (IFN) production by peripheral blood mononuclear (PBM) cells of an elderly population

    International Nuclear Information System (INIS)

    Previous investigations in the laboratory have reported decreased mitogen responses of PBM's from elderly individuals compared to responses of young adults to PHA and ConA. Current studies have investigated the role of IFN in this decreased T cell responsiveness of the elderly. Supernatants of PBM's from 80 elderly (mean age 85) and 50 young individuals (mean age 28) were assayed for antiviral activity, after incubation with optimum and supraoptimum concentrations of mitogen for 24-120 hrs. IFN levels were maximum for both elderly and young populations at 72 hrs coinciding with time of maximum proliferation as determined by uptake of 3H thymidine. IFN levels declined with longer incubation periods. All IFN produced was IFN-gamma as determined by sensitivity to pH 2 and by neutralizations with monoclonal antibody specific for human IFN-gamma and polyclonal antiserum specific for IFN-alpha. The elderly population's mean IFN titers for both PHA and ConA were about 39% of the mean titers of the young (p ≤ 0.02). Both elderly and young groups displayed significant positive correlation between the amount of IFN produced and the level of proliferation in response to the mitogens (p ≤ 0.036). Therefore, the above data suggests the decreased levels of IFN produced by elderly PBM's may be one of the factors responsible for the observed decreased proliferative response to mitogens

  7. Development of a population of cancer cells: Observation and modeling by a Mixed Spatial Evolutionary Games approach.

    Science.gov (United States)

    Świerniak, Andrzej; Krześlak, Michał; Student, Sebastian; Rzeszowska-Wolny, Joanna

    2016-09-21

    Living cells, like whole living organisms during evolution, communicate with their neighbors, interact with the environment, divide, change their phenotypes, and eventually die. The development of specific ways of communication (through signaling molecules and receptors) allows some cellular subpopulations to survive better, to coordinate their physiological status, and during embryonal development to create tissues and organs or in some conditions to become tumors. Populations of cells cultured in vitro interact similarly, also competing for space and nutrients and stimulating each other to better survive or to die. The results of these intercellular interactions of different types seem to be good examples of biological evolutionary games, and have been the subjects of simulations by the methods of evolutionary game theory where individual cells are treated as players. Here we present examples of intercellular contacts in a population of living human cancer HeLa cells cultured in vitro and propose an evolutionary game theory approach to model the development of such populations. We propose a new technique termed Mixed Spatial Evolutionary Games (MSEG) which are played on multiple lattices corresponding to the possible cellular phenotypes which gives the possibility of simulating and investigating the effects of heterogeneity at the cellular level in addition to the population level. Analyses performed with MSEG suggested different ways in which cellular populations develop in the case of cells communicating directly and through factors released to the environment. PMID:27216640

  8. Neurochemical phenotype and birthdating of specific cell populations in the chick retina

    Directory of Open Access Journals (Sweden)

    Karin da Costa calaza

    2010-09-01

    Full Text Available The chick embryo is one of the most traditional models in developing neuroscience and its visual system has been one of the most exhaustively studied. The retina has been used as a model for studying the development of the nervous system. Here, we describe the morphological features that characterize each stage of the retina development and studies of the neurogenesis period of some specific neurochemical subpopulations of retinal cells by using a combination of immunohistochemistry and autoradiography of tritiated-thymidine. It could be concluded that the proliferation period of dopaminergic, GABAergic, cholinoceptive and GABAceptive cells does not follow a common rule of the neurogenesis. In addition, some specific neurochemical cell groups can have a restrict proliferation period when compared to the total cell population.O embrião de galinha é um dos mais tradicionais modelosde estudos da neurociência do desenvolvimento e seu sistema visual tem sido um dos mais exaustivamente estudado. Aretina tem sido utilizada como modelo para estudar o desenvolvimento do sistema nervoso. Aqui, nós descrevemos as características morfológicas que caracterizam cada estádio da retina em desenvolvimento e os estudos do período de neurogênese de algumas subpopulações de células neuroquímicamente específicas da retina usando uma combinação de imunohistoquímica e autoradiografia de timidina-tritiada. Conclui-se que o período de proliferação das células dopaminérgicas, GABAérgicas, colinoceptivas e GABAceptivas não segue uma regra comum. Além disso, alguns grupos celulares neuroquimicamente distintos podem ter um período de proliferaçãomais restrito quando comparado ao da população total destas células.

  9. Mapping the distinctive populations of lymphatic endothelial cells in different zones of human lymph nodes.

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    Saem Mul Park

    Full Text Available The lymphatic sinuses in human lymph nodes (LNs are crucial to LN function yet their structure remains poorly defined. Much of our current knowledge of lymphatic sinuses derives from rodent models, however human LNs differ substantially in their sinus structure, most notably due to the presence of trabeculae and trabecular lymphatic sinuses that rodent LNs lack. Lymphatic sinuses are bounded and traversed by lymphatic endothelial cells (LECs. A better understanding of LECs in human LNs is likely to improve our understanding of the regulation of cell trafficking within LNs, now an important therapeutic target, as well as disease processes that involve lymphatic sinuses. We therefore sought to map all the LECs within human LNs using multicolor immunofluorescence microscopy to visualize the distribution of a range of putative markers. PROX1 was the only marker that uniquely identified the LECs lining and traversing all the sinuses in human LNs. In contrast, LYVE1 and STAB2 were only expressed by LECs in the paracortical and medullary sinuses in the vast majority of LNs studied, whilst the subcapsular and trabecular sinuses lacked these molecules. These data highlight the existence of at least two distinctive populations of LECs within human LNs. Of the other LEC markers, we confirmed VEGFR3 was not specific for LECs, and CD144 and CD31 stained both LECs and blood vascular endothelial cells (BECs; in contrast, CD59 and CD105 stained BECs but not LECs. We also showed that antigen-presenting cells (APCs in the sinuses could be clearly distinguished from LECs by their expression of CD169, and their lack of expression of PROX1 and STAB2, or endothelial markers such as CD144. However, both LECs and sinus APCs were stained with DCN46, an antibody commonly used to detect CD209.

  10. CD4(+)CD25 (+)CD127 (low/-) T cells: a more specific Treg population in human peripheral blood.

    Science.gov (United States)

    Yu, Ning; Li, Xiaomei; Song, Weiya; Li, Dongmei; Yu, Daliang; Zeng, Xiaofeng; Li, Mengtao; Leng, Xiaomei; Li, Xiangpei

    2012-12-01

    The quantitative identification and enrichment of viable regulatory T cells (Treg) requires reliable surface markers that are selectively expressed on Treg. Foxp3 is the accepted marker of nTreg, but it cannot be used to isolate cells for functional studies. In this study, we compared four staining profiles of Treg, including CD4(+)CD25(high) T cells, CD4(+)CD39(+) T cells, CD4(+)CD73(+) T cells, and CD4(+)CD25(+)CD127(low/-) T cells. We found that CD4(+)CD25(+)CD127(low/-) T cells expressed the highest level of Foxp3 and had the strongest correlation with CD4(+)CD25(+)Foxp3(+) T cells, the accepted identifying characteristics for "real" nTreg cells. Moreover, functional data showed that CD4(+)CD25(+)CD127(low/-) T cells could effectively suppress the proliferation of CD4(+)CD25(-) T cells, suggesting that compared with the other three populations, CD4(+)CD25(+)CD127(low/-) T cells best fit the definition of naturally occurring regulatory T cells in human peripheral blood. Finally, we showed that CD4(+)CD25(+)CD127(low/-) can be used to quantitate Treg cells in individuals with systemic lupus erythematosus supporting the use of CD4(+)CD25(+)CD127(low/-) to identify human Treg cells. PMID:22752562

  11. Isolation and characterisation of human gingival margin-derived STRO-1/MACS1 and MACS2 cell populations

    Institute of Scientific and Technical Information of China (English)

    Karim M Fawzy El-Sayed; Sebastian Paris; Christian Graetz; Neemat Kassem; Mohamed Mekhemar; Hendrick Ungefroren; Fred Fandrich; Christof Dorfer

    2015-01-01

    Recently, gingival margin-derived stem/progenitor cells isolated via STRO-1/magnetic activated cell sorting (MACS) showed remarkable periodontal regenerative potential in vivo. As a second-stage investigation, the present study’s aim was to perform in vitro characterisation and comparison of the stem/progenitor cell characteristics of sorted STRO-1-positive (MACS1) and STRO-1-negative (MACS2) cell populations from the human free gingival margin. Cells were isolated from the free gingiva using a minimally invasive technique and were magnetically sorted using anti-STRO-1 antibodies. Subsequently, the MACS1 and MACS2 cell fractions were characterized by flow cytometry for expression of CD14, CD34, CD45, CD73, CD90, CD105, CD146/MUC18 and STRO-1. Colony-forming unit (CFU) and multilineage differentiation potential were assayed for both cell fractions. Mineralisation marker expression was examined using real-time polymerase chain reaction (PCR). MACS1 and MACS2 cell fractions showed plastic adherence. MACS1 cells, in contrast to MACS2 cells, showed all of the predefined mesenchymal stem/progenitor cell characteristics and a significantly higher number of CFUs (P,0.01). More than 95%of MACS1 cells expressed CD105, CD90 and CD73;lacked the haematopoietic markers CD45, CD34 and CD14, and expressed STRO-1 and CD146/MUC18. MACS2 cells showed a different surface marker expression profile, with almost no expression of CD14 or STRO-1, and more than 95%of these cells expressed CD73, CD90 and CD146/MUC18, as well as the haematopoietic markers CD34 and CD45 and CD105. MACS1 cells could be differentiated along osteoblastic, adipocytic and chondroblastic lineages. In contrast, MACS2 cells demonstrated slight osteogenic potential. Unstimulated MACS1 cells showed significantly higher expression of collagen I (P,0.05) and collagen III (P,0.01), whereas MACS2 cells demonstrated higher expression of osteonectin (P,0.05;Mann–Whitney). The present study is the first to compare gingival

  12. Uptake of 3H-thymidine by the receptor cell populations after injury of the sensory nerve fibres

    International Nuclear Information System (INIS)

    The material of the study was the skin from the beak of two-day ducklings. The investigation was carried out on the 2nd, 5th, 20th and 45th day after the crushing of the sensory nerve fibres entering the capsulated Herbst receptors. Twenty four hours before the biopsy, the ducklings were injected at 6 hours intervals with 3H-thymidine. The number of labelled index in the three cell pupulations, participating in the receptor development was determined. The cells of the subcapsular space of all control animals (with intacted suborbital nerves) have shown the highest labelled index. The index of the capsular perineural cells is about 12 times lower, while the labelled index of the Schwann receptor cells is about 10 times lower. Following the denervation, the labelled index in increasing and reaches its maximum on the 5th postoperative day. The Schwann receptor cells in comparison to the two other cell populations show the most significant deviation during the regeneration (45th day after the intervention). The investigations show that all three cell populations pass through a miotic cycle of innovation. The low labelled index of the Schwann receptors (1-2 labelled cells in 1000) is an indication of a high differentiation. One can assume that their regeneration takes place at the expense of the proper proliferation activity as well as of the differentiation of the Schwann cells from the distal section of the regenerating sensory nerve fibres. Taking into consideration the high labelled index of the other populations, it seems most probable that their regeneration takes place for the expense of their own cell populations. (A.B.)

  13. Hemolytic disease of fetus and newborn due to maternal red blood cell alloantibodies in the Malay population

    OpenAIRE

    Mohd Nazri Hassan; Noor Haslina Mohd Noor; Shah Reza Johan Noor; Salamah Ahmad Sukri; Rapiaah Mustafa; Hans Van Rostenberghe Luc Aster

    2014-01-01

    Background: Maternal red blood cell (RBC) alloimmunization may lead to production of harmful antibodies that result in hemolytic disease of fetus and newborn (HDFN). There is insufficient data on the prevalence of HDFN due to RBC alloantibodies in the Malay neonatal population. Aim: The aim of this study was to determine the incidence of HDFN in the Malay neonatal population due to clinically significant RBC alloantibodies. Subjects and Methods: A cross sectional study was conducted in Transf...

  14. An Economic Analysis of Cell-Free DNA Non-Invasive Prenatal Testing in the US General Pregnancy Population

    OpenAIRE

    Benn, Peter; Curnow, Kirsten J.; Chapman, Steven; Michalopoulos, Steven N.; Hornberger, John; Rabinowitz, Matthew

    2015-01-01

    Objective Analyze the economic value of replacing conventional fetal aneuploidy screening approaches with non-invasive prenatal testing (NIPT) in the general pregnancy population. Methods Using decision-analysis modeling, we compared conventional screening to NIPT with cell-free DNA (cfDNA) analysis in the annual US pregnancy population. Sensitivity and specificity for fetal aneuploidies, trisomy 21, trisomy 18, trisomy 13, and monosomy X, were estimated using published data and modeling of b...

  15. Metabolic diversity and ecological niches of Achromatium populations revealed with single-cell genomic sequencing

    Directory of Open Access Journals (Sweden)

    Muammar eMansor

    2015-08-01

    Full Text Available Large, sulfur-cycling, calcite-precipitating bacteria in the genus Achromatium represent a significant proportion of bacterial communities near sediment-water interfaces throughout the world. Our understanding of their potentially crucial roles in calcium, carbon, sulfur, nitrogen, and iron cycling is limited because they have not been cultured or sequenced using environmental genomics approaches to date. We utilized single-cell genomic sequencing to obtain one incomplete and two nearly complete draft genomes for Achromatium collected at Warm Mineral Springs, FL. Based on 16S rRNA gene sequences, the three cells represent distinct and relatively distant Achromatium populations (91-92% identity. The draft genomes encode key genes involved in sulfur and hydrogen oxidation; oxygen, nitrogen and polysulfide respiration; carbon and nitrogen fixation; organic carbon assimilation and storage; chemotaxis; twitching motility; antibiotic resistance; and membrane transport. Known genes for iron and manganese energy metabolism were not detected. The presence of pyrophosphatase and vacuolar (V-type ATPases, which are generally rare in bacterial genomes, suggests a role for these enzymes in calcium transport, proton pumping, and/or energy generation in the membranes of calcite-containing inclusions.

  16. Nuclear β-catenin and CD44 upregulation characterize invasive cell populations in non-aggressive MCF-7 breast cancer cells

    International Nuclear Information System (INIS)

    In breast cancer cells, the metastatic cell state is strongly correlated to epithelial-to-mesenchymal transition (EMT) and the CD44+/CD24- stem cell phenotype. However, the MCF-7 cell line, which has a luminal epithelial-like phenotype and lacks a CD44+/CD24- subpopulation, has rare cell populations with higher Matrigel invasive ability. Thus, what are the potentially important differences between invasive and non-invasive breast cancer cells, and are the differences related to EMT or CD44/CD24 expression? Throughout the sequential selection process using Matrigel, we obtained MCF-7-14 cells of opposite migratory and invasive capabilities from MCF-7 cells. Comparative analysis of epithelial and mesenchymal marker expression was performed between parental MCF-7, selected MCF-7-14, and aggressive mesenchymal MDA-MB-231 cells. Furthermore, using microarray expression profiles of these cells, we selected differentially expressed genes for their invasive potential, and performed pathway and network analysis to identify a set of interesting genes, which were evaluated by RT-PCR, flow cytometry or function-blocking antibody treatment. MCF-7-14 cells had enhanced migratory and invasive ability compared with MCF-7 cells. Although MCF-7-14 cells, similar to MCF-7 cells, expressed E-cadherin but neither vimentin nor fibronectin, β-catenin was expressed not only on the cell membrane but also in the nucleus. Furthermore, using gene expression profiles of MCF-7, MCF-7-14 and MDA-MB-231 cells, we demonstrated that MCF-7-14 cells have alterations in signaling pathways regulating cell migration and identified a set of genes (PIK3R1, SOCS2, BMP7, CD44 and CD24). Interestingly, MCF-7-14 and its invasive clone CL6 cells displayed increased CD44 expression and downregulated CD24 expression compared with MCF-7 cells. Anti-CD44 antibody treatment significantly decreased cell migration and invasion in both MCF-7-14 and MCF-7-14 CL6 cells as well as MDA-MB-231 cells. MCF-7-14 cells are a

  17. Recovery of the Erythropoietin-Sensitive Stem-Cell Population following Total-Body X-Irradiation

    International Nuclear Information System (INIS)

    Erythropoietin acts upon haemopoietic stem cells to initiate their differentiation into the erythroid series. This effect may be used in polycythaemic mice to estimate changes in the erythropoietin-sensitive stem-cell population following total-body irradiation (TBR). Generally, single doses of erythropoietin, less than that needed for maximum stem-cell response, are used to estimate changes in the stem-cell population. The validity of results using this test is based upon accepting several assumptions regarding erythropoietin kinetics. These are: (a) the contribution of endogenous erythropoietin is always negligible; (b) the origin of the dose-response curve to erythropoietin alters only because of changes in stem-cell numbers; (c) the proportion of stem cells responding to a given concentration of erythropoietin is independent of stem-cell numbers; (d) the slope of the dose-response curve does not alter; and (e) competition between erythropoietin and other factors for the stem cells remains unchanged. The studies to be reported indicate that some of these assumptions m a y not always be valid. Following 150 rad TBR, changes in erythropoietin dose-response curves were not always due to changes in the size of the stem-cell population, but also due to changes in erythropoietin kinetics. Changes in erythropoietin kinetics could be corrected for by using doses of erythropoietin which at any particular time after TBR gave maximum stem-cell response; through full dose-response studies, the nature of changes in erythropoietin kinetics following TBR could be established. These studies appear to explain discrepancies in results obtained in different laboratories using the erythropoietin test. The effect of 150 rad TBR on the erythropoietin-sensitive stem-cell population is an initial depression within 30 min to 20% of normal followed by a second depression (post-irradiation dip) at about 12 h. Twenty-four hours after TBR there is a recovery to the initial depression. This

  18. A novel quantitative model of cell cycle progression based on cyclin-dependent kinases activity and population balances.

    Science.gov (United States)

    Pisu, Massimo; Concas, Alessandro; Cao, Giacomo

    2015-04-01

    Cell cycle regulates proliferative cell capacity under normal or pathologic conditions, and in general it governs all in vivo/in vitro cell growth and proliferation processes. Mathematical simulation by means of reliable and predictive models represents an important tool to interpret experiment results, to facilitate the definition of the optimal operating conditions for in vitro cultivation, or to predict the effect of a specific drug in normal/pathologic mammalian cells. Along these lines, a novel model of cell cycle progression is proposed in this work. Specifically, it is based on a population balance (PB) approach that allows one to quantitatively describe cell cycle progression through the different phases experienced by each cell of the entire population during its own life. The transition between two consecutive cell cycle phases is simulated by taking advantage of the biochemical kinetic model developed by Gérard and Goldbeter (2009) which involves cyclin-dependent kinases (CDKs) whose regulation is achieved through a variety of mechanisms that include association with cyclins and protein inhibitors, phosphorylation-dephosphorylation, and cyclin synthesis or degradation. This biochemical model properly describes the entire cell cycle of mammalian cells by maintaining a sufficient level of detail useful to identify check point for transition and to estimate phase duration required by PB. Specific examples are discussed to illustrate the ability of the proposed model to simulate the effect of drugs for in vitro trials of interest in oncology, regenerative medicine and tissue engineering. PMID:25601491

  19. Cigarette smoke promotes drug resistance and expansion of cancer stem cell-like side population.

    Directory of Open Access Journals (Sweden)

    Yi An

    Full Text Available It is well known that many patients continue to smoke cigarettes after being diagnosed with cancer. Although smoking cessation has typically been presumed to possess little therapeutic value for cancer, a growing body of evidence suggests that continued smoking is associated with reduced efficacy of treatment and a higher incidence of recurrence. We therefore investigated the effect of cigarette smoke condensate (CSC on drug resistance in the lung cancer and head and neck cancer cell lines A549 and UMSCC-10B, respectively. Our results showed that CSC significantly increased the cellular efflux of doxorubicin and mitoxantrone. This was accompanied by membrane localization and increased expression of the multi-drug transporter ABCG2. The induced efflux of doxorubicin was reversed upon addition of the specific ABCG2 inhibitor Fumitremorgin C, confirming the role of ABCG2. Treatment with CSC increased the concentration of phosphorylated Akt, while addition of the PI3K inhibitor LY294002 blocked doxorubicin extrusion, suggesting that Akt activation is required for CSC-induced drug efflux. In addition, CSC was found to promote resistance to doxorubicin as determined by MTS assays. This CSC-induced doxurbicin-resistance was mitigated by mecamylamine, a nicotinic acetylcholine receptor inhibitor, suggesting that nicotine is at least partially responsible for the effect of CSC. Lastly, CSC increased the size of the side population (SP, which has been linked to a cancer stem cell-like phenotype. In summary, CSC promotes chemoresistance via Akt-mediated regulation of ABCG2 activity, and may also increase the proportion of cancer stem-like cells, contributing to tumor resilience. These findings underscore the importance of smoking cessation following a diagnosis of cancer, and elucidate the mechanisms of continued smoking that may be detrimental to treatment.

  20. Biological properties of differently-aged human keratinocytes:population doubling time growth curve and cell cycle analysis

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Objective To explore the biological properties of keratinocytes from differently-aged healthy human beings. Methods Keratinocytes from fetus,teenager and middle-aged groups were separated and cultured. The population doubling time (PDT) and cell growth curve in different cells were compared,and the cell cycles were analyzed by flow cytometry. Results ① In primary culture of keratinocytes,the adherence time in middle-aged group was longer than that in fetus and teenager groups. However,all cell morphology sh...

  1. Amplification of the spleen macrophage population in malaria: possible role of a factor chemotactic for blood mononuclear cells

    International Nuclear Information System (INIS)

    The mechanism of amplification of the splenic macrophages' population was investigated using mice infected with malaria as a model of an obligate intravascular infection. It was observed that these macrophages derived from blood monocytes rather than by local proliferation in the spleen. A factor, chemotactic for blood mononuclear cells, was present in spleen cells shortly after infection and preceded detectable increases in spleen macrophage number by 48 hours. This factor, in concert with spleen derived macrophage migration inhibition factor, may be important in the amplification of splenic macrophage population in intravascular infections

  2. Molecular signature and in vivo behavior of bone marrow endosteal and subendosteal stromal cell populations and their relevance to hematopoiesis

    International Nuclear Information System (INIS)

    In the bone marrow cavity, hematopoietic stem cells (HSC) have been shown to reside in the endosteal and subendosteal perivascular niches, which play specific roles on HSC maintenance. Although cells with long-term ability to reconstitute full hematopoietic system can be isolated from both niches, several data support a heterogenous distribution regarding the cycling behavior of HSC. Whether this distinct behavior depends upon the role played by the stromal populations which distinctly create these two niches is a question that remains open. In the present report, we used our previously described in vivo assay to demonstrate that endosteal and subendosteal stromal populations are very distinct regarding skeletal lineage differentiation potential. This was further supported by a microarray-based analysis, which also demonstrated that these two stromal populations play distinct, albeit complementary, roles in HSC niche. Both stromal populations were preferentially isolated from the trabecular region and behave distinctly in vitro, as previously reported. Even though these two niches are organized in a very close range, in vivo assays and molecular analyses allowed us to identify endosteal stroma (F-OST) cells as fully committed osteoblasts and subendosteal stroma (F-RET) cells as uncommitted mesenchymal cells mainly represented by perivascular reticular cells expressing high levels of chemokine ligand, CXCL12. Interestingly, a number of cytokines and growth factors including interleukin-6 (IL-6), IL-7, IL-15, Hepatocyte growth factor (HGF) and stem cell factor (SCF) matrix metalloproteases (MMPs) were also found to be differentially expressed by F-OST and F-RET cells. Further microarray analyses indicated important mechanisms used by the two stromal compartments in order to create and coordinate the “quiescent” and “proliferative” niches in which hematopoietic stem cells and progenitors reside.

  3. Molecular signature and in vivo behavior of bone marrow endosteal and subendosteal stromal cell populations and their relevance to hematopoiesis

    Energy Technology Data Exchange (ETDEWEB)

    Balduino, Alex, E-mail: balduino@uva.edu.br [School of Dentistry, Veiga de Almeida University, Rio de Janeiro, RJ (Brazil); Mello-Coelho, Valeria [Biomedical Science Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ (Brazil); National Institute on Aging, National Institute of Health, Baltimore, MD (United States); Wang, Zhou; Taichman, Russell S.; Krebsbach, Paul H. [Department of Periodontics, Prevention and Geriatrics, University of Michigan School of Dentistry, Ann Arbor, MI (United States); Weeraratna, Ashani T.; Becker, Kevin G. [National Institute on Aging, National Institute of Health, Baltimore, MD (United States); Mello, Wallace de [Instituto Oswaldo Cruz, Rio de Janeiro, RJ (Brazil); Taub, Dennis D. [National Institute on Aging, National Institute of Health, Baltimore, MD (United States); Borojevic, Radovan [Biomedical Science Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ (Brazil)

    2012-11-15

    In the bone marrow cavity, hematopoietic stem cells (HSC) have been shown to reside in the endosteal and subendosteal perivascular niches, which play specific roles on HSC maintenance. Although cells with long-term ability to reconstitute full hematopoietic system can be isolated from both niches, several data support a heterogenous distribution regarding the cycling behavior of HSC. Whether this distinct behavior depends upon the role played by the stromal populations which distinctly create these two niches is a question that remains open. In the present report, we used our previously described in vivo assay to demonstrate that endosteal and subendosteal stromal populations are very distinct regarding skeletal lineage differentiation potential. This was further supported by a microarray-based analysis, which also demonstrated that these two stromal populations play distinct, albeit complementary, roles in HSC niche. Both stromal populations were preferentially isolated from the trabecular region and behave distinctly in vitro, as previously reported. Even though these two niches are organized in a very close range, in vivo assays and molecular analyses allowed us to identify endosteal stroma (F-OST) cells as fully committed osteoblasts and subendosteal stroma (F-RET) cells as uncommitted mesenchymal cells mainly represented by perivascular reticular cells expressing high levels of chemokine ligand, CXCL12. Interestingly, a number of cytokines and growth factors including interleukin-6 (IL-6), IL-7, IL-15, Hepatocyte growth factor (HGF) and stem cell factor (SCF) matrix metalloproteases (MMPs) were also found to be differentially expressed by F-OST and F-RET cells. Further microarray analyses indicated important mechanisms used by the two stromal compartments in order to create and coordinate the 'quiescent' and 'proliferative' niches in which hematopoietic stem cells and progenitors reside.

  4. A computational model incorporating neural stem cell dynamics reproduces glioma incidence across the lifespan in the human population.

    Directory of Open Access Journals (Sweden)

    Roman Bauer

    Full Text Available Glioma is the most common form of primary brain tumor. Demographically, the risk of occurrence increases until old age. Here we present a novel computational model to reproduce the probability of glioma incidence across the lifespan. Previous mathematical models explaining glioma incidence are framed in a rather abstract way, and do not directly relate to empirical findings. To decrease this gap between theory and experimental observations, we incorporate recent data on cellular and molecular factors underlying gliomagenesis. Since evidence implicates the adult neural stem cell as the likely cell-of-origin of glioma, we have incorporated empirically-determined estimates of neural stem cell number, cell division rate, mutation rate and oncogenic potential into our model. We demonstrate that our model yields results which match actual demographic data in the human population. In particular, this model accounts for the observed peak incidence of glioma at approximately 80 years of age, without the need to assert differential susceptibility throughout the population. Overall, our model supports the hypothesis that glioma is caused by randomly-occurring oncogenic mutations within the neural stem cell population. Based on this model, we assess the influence of the (experimentally indicated decrease in the number of neural stem cells and increase of cell division rate during aging. Our model provides multiple testable predictions, and suggests that different temporal sequences of oncogenic mutations can lead to tumorigenesis. Finally, we conclude that four or five oncogenic mutations are sufficient for the formation of glioma.

  5. Bioluminescence imaging of leukemia cell lines in vitro and in mouse xenografts: effects of monoclonal and polyclonal cell populations on intensity and kinetics of photon emission

    Directory of Open Access Journals (Sweden)

    Christoph Sandra

    2013-01-01

    Full Text Available Abstract Background We investigated the utility of bioluminescence imaging (BLI using firefly luciferase in monoclonal and polyclonal populations of leukemia cells in vitro and in vivo. Methods Monoclonal and polyclonal human lymphoid and myeloid leukemia cell lines transduced with firefly luciferase were used for BLI. Results Kinetics and dynamics of bioluminescence signal were cell line dependent. Luciferase expression decreased significantly over time in polyclonal leukemia cells in vitro. Transplantation of polyclonal luciferase-tagged cells in mice resulted in inconsistent signal intensity. After selection of monoclonal cell populations, luciferase activity was stable, equal kinetic and dynamic of bioluminescence intensity and strong correlation between cell number and light emission in vitro were observed. We obtained an equal development of leukemia burden detected by luciferase activity in NOD-scid-gamma mice after transplantation of monoclonal populations. Conclusion The use of monoclonal leukemia cells selected for stable and equal luciferase activity is recommended for experiments in vitro and xenograft mouse models. The findings are highly significant for bioluminescence imaging focused on pre-clinical drug development.

  6. Mutational dynamics of the SARS coronavirus in cell culture and human populations isolated in 2003

    Directory of Open Access Journals (Sweden)

    Ooi Eng

    2004-09-01

    Full Text Available Abstract Background The SARS coronavirus is the etiologic agent for the epidemic of the Severe Acute Respiratory Syndrome. The recent emergence of this new pathogen, the careful tracing of its transmission patterns, and the ability to propagate in culture allows the exploration of the mutational dynamics of the SARS-CoV in human populations. Methods We sequenced complete SARS-CoV genomes taken from primary human tissues (SIN3408, SIN3725V, SIN3765V, cultured isolates (SIN848, SIN846, SIN842, SIN845, SIN847, SIN849, SIN850, SIN852, SIN3408L, and five consecutive Vero cell passages (SIN2774_P1, SIN2774_P2, SIN2774_P3, SIN2774_P4, SIN2774_P5 arising from SIN2774 isolate. These represented individual patient samples, serial in vitro passages in cell culture, and paired human and cell culture isolates. Employing a refined mutation filtering scheme and constant mutation rate model, the mutation rates were estimated and the possible date of emergence was calculated. Phylogenetic analysis was used to uncover molecular relationships between the isolates. Results Close examination of whole genome sequence of 54 SARS-CoV isolates identified before 14th October 2003, including 22 from patients in Singapore, revealed the mutations engendered during human-to-Vero and Vero-to-human transmission as well as in multiple Vero cell passages in order to refine our analysis of human-to-human transmission. Though co-infection by different quasipecies in individual tissue samples is observed, the in vitro mutation rate of the SARS-CoV in Vero cell passage is negligible. The in vivo mutation rate, however, is consistent with estimates of other RNA viruses at approximately 5.7 × 10-6 nucleotide substitutions per site per day (0.17 mutations per genome per day, or two mutations per human passage (adjusted R-square = 0.4014. Using the immediate Hotel M contact isolates as roots, we observed that the SARS epidemic has generated four major genetic groups that are

  7. Use of three-dimensional time-resolved phase-contrast magnetic resonance imaging with vastly undersampled isotropic projection reconstruction to assess renal blood flow in a renal cell carcinoma patient treated with sunitinib: a case report

    OpenAIRE

    Takayama, Tatsuya; Takehara, Yasuo; Sugiyama, Masataka; Sugiyama, Takayuki; Ishii, Yasuo; Johnson, Kevin E; Wieben, Oliver; Wakayama, Tetsuya; Sakahara, Harumi; Ozono, Seiichiro

    2014-01-01

    Background New imaging modalities to assess the efficacy of drugs that have molecular targets remain under development. Here, we describe for the first time the use of time-resolved three-dimensional phase-contrast magnetic resonance imaging to monitor changes in blood supply to a tumor during sunitinib treatment in a patient with localized renal cell carcinoma. Case presentation A 43-year-old Japanese woman with a tumor-bearing but functional single kidney presented at our hospital in July 2...

  8. Protocol for Isolation of Primary Human Hepatocytes and Corresponding Major Populations of Non-parenchymal Liver Cells.

    Science.gov (United States)

    Kegel, Victoria; Deharde, Daniela; Pfeiffer, Elisa; Zeilinger, Katrin; Seehofer, Daniel; Damm, Georg

    2016-01-01

    Beside parenchymal hepatocytes, the liver consists of non-parenchymal cells (NPC) namely Kupffer cells (KC), liver endothelial cells (LEC) and hepatic Stellate cells (HSC). Two-dimensional (2D) culture of primary human hepatocyte (PHH) is still considered as the "gold standard" for in vitro testing of drug metabolism and hepatotoxicity. It is well-known that the 2D monoculture of PHH suffers from dedifferentiation and loss of function. Recently it was shown that hepatic NPC play a central role in liver (patho-) physiology and the maintenance of PHH functions. Current research focuses on the reconstruction of in vivo tissue architecture by 3D- and co-culture models to overcome the limitations of 2D monocultures. Previously we published a method to isolate human liver cells and investigated the suitability of these cells for their use in cell cultures in Experimental Biology and Medicine(1). Based on the broad interest in this technique the aim of this article was to provide a more detailed protocol for the liver cell isolation process including a video, which will allow an easy reproduction of this technique. Human liver cells were isolated from human liver tissue samples of surgical interventions by a two-step EGTA/collagenase P perfusion technique. PHH were separated from the NPC by an initial centrifugation at 50 x g. Density gradient centrifugation steps were used for removal of dead cells. Individual liver cell populations were isolated from the enriched NPC fraction using specific cell properties and cell sorting procedures. Beside the PHH isolation we were able to separate KC, LEC and HSC for further cultivation. Taken together, the presented protocol allows the isolation of PHH and NPC in high quality and quantity from one donor tissue sample. The access to purified liver cell populations could allow the creation of in vivo like human liver models. PMID:27077489

  9. New malignancies after squamous cell carcinoma and melanomas: a population-based study from Norway

    International Nuclear Information System (INIS)

    Skin cancer survivors experience an increased risk for subsequent malignancies but the associated risk factors are poorly understood. This study examined the risk of a new primary cancer following an initial skin cancer and assessed risk factors associated with second primary cancers. All invasive cutaneous malignant melanomas (CMM, N = 28 069) and squamous cell carcinomas (SCC, N = 24 620) diagnosed in Norway during 1955–2008 were included. Rates of new primary cancers in skin cancer survivors were compared to rates of primary malignancies in the general population using standardized incidence ratios (SIR). Discrete-time logistic regression models were applied to individual-level data to estimate cancer risk among those with and without a prior skin cancer, accounting for residential region, education, income, parenthood, marital status and parental cancer status, using a 20% random sample of the entire Norwegian population as reference. Further analyses of the skin cancer cohort were undertaken to determine risk factors related to subsequent cancers. During follow-up, 9608 new primary cancers occurred after an initial skin cancer. SIR analyses showed 50% and 90% increased risks for any cancer after CMM and SCC, respectively (p < 0.01). The logistic regression model suggested even stronger increase after SCC (130%). The highest risk was seen for subsequent skin cancers, but several non-skin cancers were also diagnosed in excess: oral, lung, colon, breast, prostate, thyroid, leukemia, lymphoma and central nervous system. Factors that were associated with increased risk of subsequent cancers include male sex, older age, lower residential latitude, being married and low education and income. Parental cancer did not increase the risk of a subsequent cancer after SCC, but was a significant predictor among younger CMM survivors. Our results provide information on shared environmental and genetic risk factors for first and later cancers and may help to identify

  10. Isolating Epithelial and Epithelial-to-Mesenchymal Transition Populations from Primary Tumors by Fluorescence-Activated Cell Sorting.

    Science.gov (United States)

    Aiello, Nicole M; Rhim, Andrew D; Stanger, Ben Z

    2016-01-01

    Transgenic mice that express conditional reporters allow for the isolation of specific cell lineages. These cells can be further stratified by gene expression and collected by fluorescence-activated cell sorting (FACS) for further analysis. Using Cre-recombinase (Cre) technology we have generated a transgenic mouse line termed PKCY in which all pancreatic epithelial cells and therefore all pancreatic cancer cells are constitutively labeled with yellow fluorescent protein (YFP). We have used immunofluorescent staining for E-cadherin to divide the YFP(+) tumor population into epithelial cells (E-cadherin positive) and cells that have undergone an epithelial-to-mesenchymal transition (EMT; E-cadherin negative). This protocol describes how to prepare a tumor sample for FACS, with an emphasis on separating epithelial and EMT populations. These cells can then be used for a number of applications including, but not limited to, the generation of cell lines, gene-expression analysis by quantitative polymerase chain reaction (qPCR) or RNA sequencing, DNA sequencing, chromatin immunoprecipitation, and western blots. PMID:26729901

  11. Quantitative measurement of retinal ganglion cell populations via histology-based random forest classification.

    Science.gov (United States)

    Hedberg-Buenz, Adam; Christopher, Mark A; Lewis, Carly J; Fernandes, Kimberly A; Dutca, Laura M; Wang, Kai; Scheetz, Todd E; Abràmoff, Michael D; Libby, Richard T; Garvin, Mona K; Anderson, Michael G

    2016-05-01

    The inner surface of the retina contains a complex mixture of neurons, glia, and vasculature, including retinal ganglion cells (RGCs), the final output neurons of the retina and primary neurons that are damaged in several blinding diseases. The goal of the current work was two-fold: to assess the feasibility of using computer-assisted detection of nuclei and random forest classification to automate the quantification of RGCs in hematoxylin/eosin (H&E)-stained retinal whole-mounts; and if possible, to use the approach to examine how nuclear size influences disease susceptibility among RGC populations. To achieve this, data from RetFM-J, a semi-automated ImageJ-based module that detects, counts, and collects quantitative data on nuclei of H&E-stained whole-mounted retinas, were used in conjunction with a manually curated set of images to train a random forest classifier. To test performance, computer-derived outputs were compared to previously published features of several well-characterized mouse models of ophthalmic disease and their controls: normal C57BL/6J mice; Jun-sufficient and Jun-deficient mice subjected to controlled optic nerve crush (CONC); and DBA/2J mice with naturally occurring glaucoma. The result of these efforts was development of RetFM-Class, a command-line-based tool that uses data output from RetFM-J to perform random forest classification of cell type. Comparative testing revealed that manual and automated classifications by RetFM-Class correlated well, with 83.2% classification accuracy for RGCs. Automated characterization of C57BL/6J retinas predicted 54,642 RGCs per normal retina, and identified a 48.3% Jun-dependent loss of cells at 35 days post CONC and a 71.2% loss of RGCs among 16-month-old DBA/2J mice with glaucoma. Output from automated analyses was used to compare nuclear area among large numbers of RGCs from DBA/2J mice (n = 127,361). In aged DBA/2J mice with glaucoma, RetFM-Class detected a decrease in median and mean nucleus size

  12. Enhancement of chemosensitivity of quiescent cell populations in solid tumors by combined treatment with nicotinamide and low temperature hyperthermia

    International Nuclear Information System (INIS)

    C3H/He and Balb/c mice bearing SCC VII and EMT6/KU tumors, respectively, received continuous administration of 5-bromo-2'-deoxyuridine (BrdU) for 5 days using implanted mini-osmotic pumps to label all proliferating (P) cells. Nicotinamide was administered intraperitoneally before cisplatin injection and/or tumors were locally heated at 40degC for 60 minutes immediately after cisplatin injection. The tumors were then excised, minced and trypsinized. The tumor cell suspensions were incubated with cytochalasin-B (a cytokinesis-blocker), and the micronucleus (MN) frequency in cells without BrdU labeling (quiescent (Q) cells) was determined using immunofluorescence staining for BrdU. The MN frequency in total (P+Q) tumor cells was determined from tumors that were not pretreated with BrdU labeling. The sensitivity to cisplatin was evaluated in terms of the frequency of induced micronuclei in binuclear tumor cells (MN frequency). In both tumor systems, the MN frequency in Q cells was lower than that in the total cell population. Nicotinamide treatment elevated the MN frequency in total SCC VII cells. Mild heating raised the MN frequency more markedly in Q cells than total cells. The combination of nicotinamide and mild heat treatment increased the MN frequency more markedly than either treatment alone. In total SCC VII cells, nicotinamide increased 195mPt-cisplatin uptake. Mild heating elevated 195mPt-cisplatin uptake in total EMT6/KU cells. Cisplatin-sensitivity of Q cells was lower than that of total cells in both tumor systems. Nicotinamide sensitized tumor cells including a large acutely hypoxic fraction such as those of SCC VII tumors through inhibition of the fluctuations in tumor blood flow. Tumor cells including a large chronically hypoxic fraction such as Q cells were thought to be sensitized by mild heating through an increase in tumor blood flow. (author)

  13. Characterization of cancer stem-like cells derived from a side population of a human gallbladder carcinoma cell line, SGC-996

    International Nuclear Information System (INIS)

    Highlights: ► We sorted SP cells from a human gallbladder carcinoma cell lines, SGC-996. ► SP cells displayed higher proliferation and stronger clonal-generating capability. ► SP cells showed more migratory and invasive abilities. ► SP cells were more resistant and tumorigenic than non-SP counterparts. ► ABCG2 might be a candidate as a marker for SP cells. -- Abstract: The cancer stem cell (CSC) hypothesis proposes that CSCs, which can renew themselves proliferate infinitely, and escape chemotherapy, become the root of recurrence and metastasis. Previous studies have verified that side population (SP) cells, characterized by their ability to efflux lipophilic substrate Hoechst 33342, to share many characteristics of CSCs in multiplying solid tumors. The purpose of this study was to sort SP cells from a human gallbladder carcinoma cell line, SGC-996 and to preliminarily identify the biological characteristics of SP cells from the cell line. Using flow cytometry we effectively sorted SP cells from the cell line SGC-996. SP cells not only displayed higher proliferative, stronger clonal-generating, more migratory and more invasive capacities, but showed stronger resistance. Furthermore, our experiments demonstrated that SP cells were more tumorigenic than non-SP counterparts in vivo. Real-time PCR analysis and immunocytochemistry showed that the expression of ATP-binding cassette subfamily G member 2 (ABCG2) was significantly higher in SP cells. Hence, these results collectively suggest that SP cells are progenitor/stem-like cells and ABCG2 might be a candidate marker for SP cells in human gallbladder cancer.

  14. Characterization of cancer stem-like cells derived from a side population of a human gallbladder carcinoma cell line, SGC-996

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xin-xing [Division of General Surgery, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127 (China); Wang, Jian, E-mail: dr_wangjian@yahoo.com.cn [Division of General Surgery, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127 (China); Wang, Hao-lu; Wang, Wei; Yin, Xiao-bin; Li, Qi-wei [Division of General Surgery, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127 (China); Chen, Yu-ying; Yi, Jing [Department of Biochemistry and Molecular Cell Biology, Key Laboratory of the Education Ministry for Cell Differentiation and Apoptosis, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025 (China)

    2012-03-23

    Highlights: Black-Right-Pointing-Pointer We sorted SP cells from a human gallbladder carcinoma cell lines, SGC-996. Black-Right-Pointing-Pointer SP cells displayed higher proliferation and stronger clonal-generating capability. Black-Right-Pointing-Pointer SP cells showed more migratory and invasive abilities. Black-Right-Pointing-Pointer SP cells were more resistant and tumorigenic than non-SP counterparts. Black-Right-Pointing-Pointer ABCG2 might be a candidate as a marker for SP cells. -- Abstract: The cancer stem cell (CSC) hypothesis proposes that CSCs, which can renew themselves proliferate infinitely, and escape chemotherapy, become the root of recurrence and metastasis. Previous studies have verified that side population (SP) cells, characterized by their ability to efflux lipophilic substrate Hoechst 33342, to share many characteristics of CSCs in multiplying solid tumors. The purpose of this study was to sort SP cells from a human gallbladder carcinoma cell line, SGC-996 and to preliminarily identify the biological characteristics of SP cells from the cell line. Using flow cytometry we effectively sorted SP cells from the cell line SGC-996. SP cells not only displayed higher proliferative, stronger clonal-generating, more migratory and more invasive capacities, but showed stronger resistance. Furthermore, our experiments demonstrated that SP cells were more tumorigenic than non-SP counterparts in vivo. Real-time PCR analysis and immunocytochemistry showed that the expression of ATP-binding cassette subfamily G member 2 (ABCG2) was significantly higher in SP cells. Hence, these results collectively suggest that SP cells are progenitor/stem-like cells and ABCG2 might be a candidate marker for SP cells in human gallbladder cancer.

  15. Identification of a sub-population of B cells that proliferates after infection with epstein-barr virus

    Directory of Open Access Journals (Sweden)

    Ye Jianjiang

    2011-02-01

    Full Text Available Abstract Background Epstein-Barr virus (EBV-driven B cell proliferation is critical to its subsequent persistence in the host and is a key event in the development of EBV-associated B cell diseases. Thus, inquiry into early cellular events that precede EBV-driven proliferation of B cells is essential for understanding the processes that can lead to EBV-associated B cell diseases. Methods Infection with high titers of EBV of mixed, primary B cells in different stages of differentiation occurs during primary EBV infection and in the setting of T cell-immunocompromise that predisposes to development of EBV-lymphoproliferative diseases. Using an ex vivo system that recapitulates these conditions of infection, we correlated expression of selected B cell-surface markers and intracellular cytokines with expression of EBV latency genes and cell proliferation. Results We identified CD23, CD58, and IL6, as molecules expressed at early times after EBV-infection. EBV differentially infected B cells into two distinct sub-populations of latently infected CD23+ cells: one fraction, marked as CD23hiCD58+IL6- by day 3, subsequently proliferated; another fraction, marked as CD23loCD58+, expressed IL6, a B cell growth factor, but failed to proliferate. High levels of LMP1, a critical viral oncoprotein, were expressed in individual CD23hiCD58+ and CD23loCD58+ cells, demonstrating that reduced levels of LMP1 did not explain the lack of proliferation of CD23loCD58+ cells. Differentiation stage of B cells did not appear to govern this dichotomy in outcome either. Memory or naïve B cells did not exclusively give rise to either CD23hi or IL6-expressing cells; rather memory B cells gave rise to both sub-populations of cells. Conclusions B cells are differentially susceptible to EBV-mediated proliferation despite expression of viral gene products known to be critical for continuous B cell growth. Cellular events, in addition to viral gene expression, likely play a

  16. Beta-Adrenergic Receptor Population is Up-Regulated in Chicken Skeletal Muscle Cells Treated with Forskolin

    Science.gov (United States)

    Bridge, K. Y.; Young, R. B.; Vaughn, J. R.

    1998-01-01

    Skeletal muscle hypertrophy is promoted by in vivo administration of beta-adrenergic receptor (betaAR) agonists. These compounds presumably exert their physiological action through the betaAR, and alterations in the population of betaAR could potentially change the ability of the cell to respond to the betaAR agonists. Since the intracellular chemical signal generated by the betaAR is cyclic AMP (cAMP), experiments were initiated in primary chicken muscle cell cultures to determine if artificial elevation of intracellular cAMP by treatment with forskolin would alter the population of functional betaAR expressed on the surface of muscle cells. Chicken skeletal muscle cells after 7 days in culture were employed for the experiments because muscle cells have attained a steady state with respect to muscle protein metabolism at this stage. Cells were treated with 0-10 microM forskolin for a total of three days. At the end of the 1, 2, and 3 day treatment intervals, the concentration of cAMP and the betaAR population were measured. Receptor population was measured in intact muscle cell cultures as the difference between total binding of [H-3]CGP-12177 and non-specific binding of [H-3]CGP-12177 in the presence of 1 microM propranolol. Intracellular cAMP concentration was measured by radioimmunoassay. The concentration of cAMP in forskolin-treated cells increased up to 10-fold in a dose dependent manner. Increasing concentrations of forskolin also led to an increase in betaAR population, with a maximum increase of approximately 50% at 10 microM. This increase in PAR population was apparent after only 1 day of treatment, and the pattern of increase was maintained for all 3 days of the treatment period. Thus, increasing the intracellular concentration of cAMP leads to up-regulation of betaAR population. The effect of forskolin on the quantity and apparent synthesis rate of the heavy chain of myosin (mhc) were also investigated. A maximum increase of 50% in the quantity of mhc

  17. Early B-cell Factor gene association with multiple sclerosis in the Spanish population

    Directory of Open Access Journals (Sweden)

    Fernández-Arquero Miguel

    2005-10-01

    Full Text Available Abstract Background The etiology of multiple sclerosis (MS is at present not fully elucidated, although it is considered to result from the interaction of environmental and genetic susceptibility factors. In this work we aimed at testing the Early B-cell Factor (EBF1 gene as a functional and positional candidate risk factor for this neurological disease. Axonal damage is a hallmark for multiple sclerosis clinical disability and EBF plays an evolutionarily conserved role in the expression of proteins essential for axonal pathfinding. Failure of B-cell differentiation was found in EBF-deficient mice and involvement of B-lymphocytes in MS has been suggested from their presence in cerebrospinal fluid and lesions of patients. Methods The role of the EBF1 gene in multiple sclerosis susceptibility was analyzed by performing a case-control study with 356 multiple sclerosis patients and 540 ethnically matched controls comparing the EBF1 polymorphism rs1368297 and the microsatellite D5S2038. Results Significant association of an EBF1-intronic polymorphism (rs1368297, A vs. T: p = 0.02; OR = 1.26 and AA vs. [TA+TT]: p = 0.02; OR = 1.39 was discovered. This association was even stronger after stratification for the well-established risk factor of multiple sclerosis in the Major Histocompatibility Complex, DRB1*1501 (AA vs. [TA+TT]: p = 0.005; OR = 1.78. A trend for association in the case-control study of another EBF1 marker, the allele 5 of the very informative microsatellite D5S2038, was corroborated by Transmission Disequilibrium Test of 53 trios (p = 0.03. Conclusion Our data support EBF1 gene association with MS pathogenesis in the Spanish white population. Two genetic markers within the EBF1 gene have been found associated with this neurological disease, indicative either of their causative role or that of some other polymorphism in linkage disequilibrium with them.

  18. Unrelated hematopoietic stem cell transplantation in the pediatric population: single institution experience

    Directory of Open Access Journals (Sweden)

    Daniela Hespanha Marinho

    2015-08-01

    Full Text Available OBJECTIVE: Hematopoietic stem cell transplantation has been successfully used to treat the pediatric population with malignant and non-malignant hematological diseases. This paper reports the results up to 180 days after the procedure of all unrelated hematopoietic stem cell transplantations in pediatric patients that were performed in one institution.METHODS: A retrospective review was performed of all under 18-year-old patients who received unrelated transplantations between 1995 and 2009. Data were analyzed using the log-rank test, Cox stepwise model, Kaplan-Meier method, Fine and Gray model and Fisher's exact test.RESULTS: This study included 118 patients (46.8% who received bone marrow and 134 (53.2% who received umbilical cord blood transplants. Engraftment occurred in 89.47% of the patients that received bone marrow and 65.83% of those that received umbilical cord blood (p-value < 0.001. Both neutrophil and platelet engraftments were faster in the bone marrow group. Acute graft-versus-host disease occurred in 48.6% of the patients without statistically significant differences between the two groups (p-value = 0.653. Chronic graft-versus-host disease occurred in 9.2% of the patients with a higher incidence in the bone marrow group (p-value = 0.007. Relapse occurred in 24% of the 96 patients with malignant disease with 2-year cumulative incidences of 45% in the bone marrow group and 25% in the umbilical cord blood group (p-value = 0.117. Five-year overall survival was 47%, with an average survival time of 1207 days, and no significant differences between the groups (p-value = 0.4666.CONCLUSION: Despite delayed engraftment in the umbilical cord blood group, graft-versus-host disease, relapse and survival were similar in both groups.

  19. Endothelial dysfunction in ankylosing spondylitis associated with reduced endothelial progenitor cell population

    Directory of Open Access Journals (Sweden)

    Pawan Krishan

    2015-06-01

    Full Text Available Background: Endothelial dysfunction, and cardiovascular (CV morbidity and mortality have been documented in patients with ankylosing spondylitis (AS. Endothelial progenitor cells (EPCs have reparative potential in overcoming the endothelial dysfunction and reducing cardiovascular risk. Aim: To investigate the relationship between endothelial function and EPCs in patients with AS in a cross-sectional study. Methods: Circulating EPCs (CD34+/CD133+ were isolated and quantified from peripheral blood samples of AS (n23 and healthy controls (n=20 matched for age and sex. Endothelium-depended vascular function, i.e. flow-mediated dilation (FMD, was assessed for all subjects. Disease activity was evaluated using Bath Ankylosing Spondylitis Disease Activity Index (BASDAI. Functional ability was monitored using Bath Ankylosing Spondylitis Functional Index (BASFI. All subjects were free of any other known traditional CV risk factors. Results: AS patients had depleted level of circulating %EPCs (0.028 ± 0.001% versus 0.045 ± 0.011%, P <0.001 and reduced FMD% (6.77 ± 2.15 versus 10.06 ± 0.55, P <0.001 than healthy controls. Circulating EPC population significantly positively correlated with FMD% (r 0.538, P = 0.008. Levels of CD34+/CD133+ putative cells showed a significant inverse correlation with disease duration (P = 0.01, BASDAI (P = 0.04, ESR (P = 0.002 and CRP (P = 0.007. Conclusion: AS patients, free of any other known CV risk factors, demonstrated depleted levels of EPCs and reduced endothelial function. These alterations may cause further deterioration of endothelial function in AS patients. EPC would possibly serve as a novel therapeutic target for preventing cardiovascular risk in AS.

  20. Biomarker screening of oral cancer cell lines revealed sub-populations of CD133-, CD44-, CD24- and ALDH1- positive cancer stem cells

    Directory of Open Access Journals (Sweden)

    Kendall K

    2013-05-01

    Full Text Available Head and neck squamous cell carcinoma (HNSCC ranks sixth worldwide for cancer-related mortality. For the past several decades the mainstay of treatment for HNSCC has been surgery and external beam radiation, although more recent trials combining chemotherapy and radiation have demonstrated improvements. However, cancer recurrence and treatment failures continue to occur in a significant percentage of patients. Recent advances in tumor biology have led to the discovery that many cancers, including HNSCC, may contain subpopulations of cells with stem cell-like properties that may explain relapse and recurrence. The objective of this study was to screen existing oral cancer cell lines for biomarkers specific for cells with stem cell-like properties. RNA was isolated for RT-PCR screening using primers for specific mRNA of the biomarkers: CD44, CD24, CD133, NANOG, Nestin, ALDH1, and ABCG2 in CAL27, SCC25 and SCC15 cells. This analysis revealed that some oral cancer cell lines (CAL27 and SCC25 may contain small subpopulations of adhesion- and contact-independent cells (AiDC that also express tumor stem cell markers, including CD44, CD133, and CD24. In addition, CAL27 cells also expressed the intracellular tumor stem cell markers, ALDH1 and ABCG2. Isolation and culture of the adhesion- and contact-independent cells from CAL27 and SCC25 populations revealed differential proliferation rates and more robust inhibition by the MEK inhibitor PD98059, as well as the chemotherapeutic agents Cisplatin and Paclitaxel, within the AiDC CAL27 cells. At least one oral cancer cell line (CAL27 contained subpopulations of cells that express specific biomarkers associated with tumor stem cells which were morphologically and phenotypically distinct from other cells within this cell line.

  1. Kinetics of Infection and Effects on Placental Cell Populations in a Murine Model of Chlamydia psittaci-Induced Abortion

    Science.gov (United States)

    Buendía, Antonio J.; Sánchez, Joaquín; Martínez, María C.; Cámara, Paulina; Navarro, Jose A.; Rodolakis, Annie; Salinas, Jesus

    1998-01-01

    The anatomical progression of chlamydial infection was studied in different areas of the placenta, using a mouse model and two inoculation times: early pregnancy (day 7, group A) and midpregnancy (day 11, group B). The first population cells affected were decidual cells and neutrophils located just at the limits of the maternal and fetal placenta. The following invaded area was the layer of giant cells. Complete colonization of the maternal placenta occurred after day 15 of pregnancy independently of the inoculation time, the metrial gland being the last area to be invaded; numerous granulated metrial gland (GMG) cells were infected. Finally, chlamydial inclusions were observed in labyrinthine trophoblastic cells from day 18 of pregnancy onward. Since no fetal damage was observed, it seems that an indirect mechanism involving the lysis of GMG cells and neutrophil infiltration of the decidua and metrial gland may be the pathogenic mechanism that leads to abortion. PMID:9573099

  2. Detection of clonal T cell populations by high resolution PCR using fluorescently labelled nucleotides; evaluation using conventional LIS-SSCP

    OpenAIRE

    Wickham, C L; Lynas, C; Ellard, S

    2000-01-01

    Aims—To detect clonal T cell populations by high resolution polymerase chain reaction (PCR) using fluorescently labelled nucleotides and analysis on an ABI 377 DNA sequencer, and to evaluate this method using low ionic strength single strand conformation polymorphism (LIS-SSCP) analysis.

  3. A double-blind, randomized quantitative comparison of calcitriol ointment and calcipotriol ointment on epidermal cell populations, proliferation and differentiation.

    NARCIS (Netherlands)

    Korver, J.E.M.; Vissers, W.H.P.M.; Rens, D.W.A. van; Pasch, M.C.; Erp, P.E.J. van; Boezeman, J.B.M.; Kerkhof, P.C.M. van de

    2007-01-01

    BACKGROUND: Calcitriol and calcipotriol are widely used in the topical treatment of psoriasis. However, studies comparing both treatment modalities are scarce. Especially, there are almost no studies comparing the effects on epidermal cell populations in a quantitative manner. OBJECTIVES: The aim of

  4. Study on sickle cell disease haplotypes reveals the African origin of Amapá's population

    Directory of Open Access Journals (Sweden)

    Natália de Morais Castelo

    2014-04-01

    Full Text Available Introduction:Sickle cell disease (SCD is a hereditary, hematologic, multifactorial disease, with high prevalence worldwide; its cause is a mutation in the sixth codon of the beta globin gene (βs.Objective:To identify the haplotypes present in people with SCD in Amapá, and relate them to African descent.Methods:We analyzed, by molecular techniques, 46 blood samples from people with SCD in Macapá, the capital of Amapá, with the purpose of obtaining information about haplotype frequency distribution, which helps understand the ethnic background of Amapá's population.Results:Our study revealed that the most frequent haplotype is Bantu (61.2%, followed by Benin (26.6% and Senegal (12.2%. Results showed statistical differences from studies conducted in other regions. A high frequency of the Senegal haplotype stands out, in comparison with some Brazilian studies.Conclusion:Amapá's results exhibit unique characteristics when compared to haplotypes in other regions, with high frequency of Senegal and Benin haplotypes, absence of atypical, Cameroon and Saudi, confirming that Brazil shows ethnic background diversity, as well as different haplotype frequencies.

  5. Multi-level behaviours in agent-based simulation: colonic crypt cell populations

    Science.gov (United States)

    Chen, Chih-Chun; Nagl, Sylvia B.; Clack, Christopher D.

    Agent-based modelling and simulation is now beginning to establish itself as a suitable technique for studying biological systems. However, a major issue in using agent-based simulations to study complex systems such as those in Systems Biology is the fact that simulations are `opaque'. While we have knowledge of individuals' behaviour through agent rules and have techniques for evaluating global behaviour by aggregating the states of individuals, methods for identifying the interactive mechanisms giving rise to this global behaviour are lacking. Formulating precise hypotheses about these multi-level behaviours is also difficult without an established formalism for describing them. The complex event formalism allows relationships between agent-rule-generated events to be defined so that behaviours at different levels of abstraction to be described. Complex event types define categories of these behaviours, which can then be detected in simulation, giving us computational method for distinguishing between alternative interactive mechanisms underlying a higher level behaviour. We apply the complex event formalism to an agent-based model of cell populations in the colonic crypt and demonstrate how competition and selection events can be identified in simulation at both the individual and clonal level, allowing us to computationally test hypotheses about the interactive mechanisms underlying a clone's success.

  6. Retroviral-infection increases tumorigenic potential of MDA-MB-231 breast carcinoma cells by expanding an aldehyde dehydrogenase (ALDH1 positive stem-cell like population

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    Lauren J. Wegman-Points

    2014-01-01

    Full Text Available Retroviral transformation has been associated with pro-proliferative oncogenic signaling in human cells. The current study demonstrates that transduction of human breast carcinoma cells (MDA-MB231 with LXSN and QCXIP retroviral vectors causes significant increases in growth rate, clonogenic fraction, and aldehyde dehydrogenase-1 positive cells (ALDH1+, which is associated with increased steady-state levels of cancer stem cell populations. Furthermore, this retroviral-induced enhancement of cancer cell growth in vitro was also accompanied by a significant increase in xenograft tumor growth rate in vivo. The retroviral induced increases in cancer cell growth rate were partially inhibited by treatment with 100 U/ml polyethylene glycol-conjugated-(PEG-superoxide dismutase and/or PEG-catalase. These results show that retroviral infection of MDA-MB231 human breast cancer cells is capable of enhancing cell proliferation and cancer stem cell populations as well as suggesting that modulation of reactive oxygen species-induced pro-survival signaling pathways may be involved in these effects.

  7. Effect of Intrinsic Noise on the Phenotype of Cell Populations Featuring Solution Multiplicity: An Artificial lac Operon Network Paradigm.

    Science.gov (United States)

    Aviziotis, Ioannis G; Kavousanakis, Michail E; Boudouvis, Andreas G

    2015-01-01

    Heterogeneity in cell populations originates from two fundamentally different sources: the uneven distribution of intracellular content during cell division, and the stochastic fluctuations of regulatory molecules existing in small amounts. Discrete stochastic models can incorporate both sources of cell heterogeneity with sufficient accuracy in the description of an isogenic cell population; however, they lack efficiency when a systems level analysis is required, due to substantial computational requirements. In this work, we study the effect of cell heterogeneity in the behaviour of isogenic cell populations carrying the genetic network of lac operon, which exhibits solution multiplicity over a wide range of extracellular conditions. For such systems, the strategy of performing solely direct temporal solutions is a prohibitive task, since a large ensemble of initial states needs to be tested in order to drive the system--through long time simulations--to possible co-existing steady state solutions. We implement a multiscale computational framework, the so-called "equation-free" methodology, which enables the performance of numerical tasks, such as the computation of coarse steady state solutions and coarse bifurcation analysis. Dynamically stable and unstable solutions are computed and the effect of intrinsic noise on the range of bistability is efficiently investigated. The results are compared with the homogeneous model, which neglects all sources of heterogeneity, with the deterministic cell population balance model, as well as with a stochastic model neglecting the heterogeneity originating from intrinsic noise effects. We show that when the effect of intrinsic source of heterogeneity is intensified, the bistability range shifts towards higher extracellular inducer concentration values. PMID:26185999

  8. Effect of Intrinsic Noise on the Phenotype of Cell Populations Featuring Solution Multiplicity: An Artificial lac Operon Network Paradigm.

    Directory of Open Access Journals (Sweden)

    Ioannis G Aviziotis

    Full Text Available Heterogeneity in cell populations originates from two fundamentally different sources: the uneven distribution of intracellular content during cell division, and the stochastic fluctuations of regulatory molecules existing in small amounts. Discrete stochastic models can incorporate both sources of cell heterogeneity with sufficient accuracy in the description of an isogenic cell population; however, they lack efficiency when a systems level analysis is required, due to substantial computational requirements. In this work, we study the effect of cell heterogeneity in the behaviour of isogenic cell populations carrying the genetic network of lac operon, which exhibits solution multiplicity over a wide range of extracellular conditions. For such systems, the strategy of performing solely direct temporal solutions is a prohibitive task, since a large ensemble of initial states needs to be tested in order to drive the system--through long time simulations--to possible co-existing steady state solutions. We implement a multiscale computational framework, the so-called "equation-free" methodology, which enables the performance of numerical tasks, such as the computation of coarse steady state solutions and coarse bifurcation analysis. Dynamically stable and unstable solutions are computed and the effect of intrinsic noise on the range of bistability is efficiently investigated. The results are compared with the homogeneous model, which neglects all sources of heterogeneity, with the deterministic cell population balance model, as well as with a stochastic model neglecting the heterogeneity originating from intrinsic noise effects. We show that when the effect of intrinsic source of heterogeneity is intensified, the bistability range shifts towards higher extracellular inducer concentration values.

  9. Axonal transmission in the retina introduces a small dispersion of relative timing in the ganglion cell population response.

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    Günther Zeck

    Full Text Available BACKGROUND: Visual stimuli elicit action potentials in tens of different retinal ganglion cells. Each ganglion cell type responds with a different latency to a given stimulus, thus transforming the high-dimensional input into a temporal neural code. The timing of the first spikes between different retinal projection neurons cells may further change along axonal transmission. The purpose of this study is to investigate if intraretinal conduction velocity leads to a synchronization or dispersion of the population signal leaving the eye. METHODOLOGY/PRINCIPAL FINDINGS: We 'imaged' the initiation and transmission of light-evoked action potentials along individual axons in the rabbit retina at micron-scale resolution using a high-density multi-transistor array. We measured unimodal conduction velocity distributions (1.3±0.3 m/sec, mean ± SD for axonal populations at all retinal eccentricities with the exception of the central part that contains myelinated axons. The velocity variance within each piece of retina is caused by ganglion cell types that show narrower and slightly different average velocity tuning. Ganglion cells of the same type respond with similar latency to spatially homogenous stimuli and conduct with similar velocity. For ganglion cells of different type intraretinal conduction velocity and response latency to flashed stimuli are negatively correlated, indicating that differences in first spike timing increase (up to 10 msec. Similarly, the analysis of pair-wise correlated activity in response to white-noise stimuli reveals that conduction velocity and response latency are negatively correlated. CONCLUSION/SIGNIFICANCE: Intraretinal conduction does not change the relative spike timing between ganglion cells of the same type but increases spike timing differences among ganglion cells of different type. The fastest retinal ganglion cells therefore act as indicators of new stimuli for postsynaptic neurons. The intraretinal dispersion

  10. Diversity of killer cell immunoglobulin-like receptor genes in Indonesian populations of Sumatra, Sulawesi and Moluccas Islands.

    Science.gov (United States)

    Velickovic, M; Velickovic, Z; Panigoro, R; Dunckley, H

    2010-10-01

    Killer immunoglobulin-like receptors (KIRs) regulate the activity of natural killer and T cells through interaction with specific human leukocyte antigen (HLA) molecules on target cells. Like HLA class I genes that are characterised by extreme allelic polymorphism, KIR genes are diverse and vary in both gene content and allelic polymorphism. Population studies conducted over the last several years have showed that KIR gene frequencies (GF) and genotype content vary among different ethnic groups, indicating the extent of KIR diversity. Some studies have also shown the effect of the presence or absence of specific KIR genes in human disease. We have recently reported the distribution of KIR genes in populations from Java (Central Javanese and the Sundanese of West Java), East Timor (Timorese), Kalimantan provinces of Indonesian Borneo (Dayaks) and Irian Jaya (Western half of the island of New Guinea; Melanese). We here extend analysis of the KIR genes in populations from North Sulawesi (Minahasans), West Sumatra (Minangs) and Moluccas Islands. All 16 KIR genes were observed in all three populations. Variation in GF between populations was observed, except for the KIR2DL4, KIR3DL2, KIR3DL3 and KIR3DP1 genes, which were present in every individual tested. When comparing KIR GF between populations, both principal component analysis and phylogenetic tree analyses showed a close relationship between Minahasan and Moluccan populations that are clustered with Timorese in the same clade. The Minang tribe lies between the Javanese/Kalimantan and the Timorese/Minahasan/Moluccan clades, whereas Irianese show the greatest genetic distances from other Indonesian populations. The results correspond well with the history of migration in Indonesia and will contribute to the understanding of the genetic as well as the geographic history of the region. PMID:20670355

  11. Photochemical stability of conjugated polymers, electron acceptors and blends for polymer solar cells resolved in terms of film thickness and absorbance

    DEFF Research Database (Denmark)

    Tromholt, Thomas; Vesterager Madsen, Morten; Carlé, Jon Eggert;

    2012-01-01

    Photochemical degradation at 1 sun under AM1.5G illumination was performed on six conjugated polymers and five different electron acceptors. Additionally, the respective polymer:PC60BM and P3HT:electron acceptor blends were studied, and all degradations were resolved in terms of film thickness and...... within each material group were found to vary for both the pure polymers and the blends. The stability ranking between the materials of the pure polymers was found to be similar to the ranking for their respective blends, implying that the photochemical stability of a pure polymer is a good measure of...... its associated blend stability. Different electron acceptors were found to stabilize P3HT decreasingly with decreasing donor–acceptor LUMO–LUMO gap. Destabilization of P3HT was observed in the case of the electron acceptor ICBA. Additionally, the decreased stabilization of P3HT by high LUMO electron...

  12. Quantitative analysis of spatially resolved electroluminescence of Cu(In,Ga)Se2 and a-Si:H thin-film solar cells and modules0

    OpenAIRE

    Tran, Thi-Minh-Hang

    2015-01-01

    Electroluminescence (EL) is the reciprocal process of the standard operational mode of a solar cell. EL imaging technique allows a fast detection of defects in solar cells and modules with low noise and high resolution. Recently, EL has become one of the most commonly used characterization tools for photovoltaic devices. There has been a significant amount of research into the interpretation and analysis of EL of silicon wafers, solar cells and modules, but very little, to date, on thin-film ...

  13. Awakened by cellular stress: isolation and characterization of a novel population of pluripotent stem cells derived from human adipose tissue.

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    Saleh Heneidi

    Full Text Available Advances in stem cell therapy face major clinical limitations, particularly challenged by low rates of post-transplant cell survival. Hostile host factors of the engraftment microenvironment such as hypoxia, nutrition deprivation, pro-inflammatory cytokines, and reactive oxygen species can each contribute to unwanted differentiation or apoptosis. In this report, we describe the isolation and characterization of a new population of adipose tissue (AT derived pluripotent stem cells, termed Multilineage Differentiating Stress-Enduring (Muse Cells, which are isolated using severe cellular stress conditions, including long-term exposure to the proteolytic enzyme collagenase, serum deprivation, low temperatures and hypoxia. Under these conditions, a highly purified population of Muse-AT cells is isolated without the utilization of cell sorting methods. Muse-AT cells grow in suspension as cell spheres reminiscent of embryonic stem cell clusters. Muse-AT cells are positive for the pluripotency markers SSEA3, TR-1-60, Oct3/4, Nanog and Sox2, and can spontaneously differentiate into mesenchymal, endodermal and ectodermal cell lineages with an efficiency of 23%, 20% and 22%, respectively. When using specific differentiation media, differentiation efficiency is greatly enhanced in Muse-AT cells (82% for mesenchymal, 75% for endodermal and 78% for ectodermal. When compared to adipose stem cells (ASCs, microarray data indicate a substantial up-regulation of Sox2, Oct3/4, and Rex1. Muse-ATs also exhibit gene expression patterns associated with the down-regulation of genes involved in cell death and survival, embryonic development, DNA replication and repair, cell cycle and potential factors related to oncogenecity. Gene expression analysis indicates that Muse-ATs and ASCs are mesenchymal in origin; however, Muse-ATs also express numerous lymphocytic and hematopoietic genes, such as CCR1 and CXCL2, encoding chemokine receptors and ligands involved in stem cell

  14. Classifying the motion of visual stimuli from the spike response of a population of retinal ganglion cells.

    Science.gov (United States)

    Cerquera, Alexander; Greschner, Martin; Freund, Jan A

    2008-01-01

    We present an analysis of the spike response of a retinal ganglion cell ensemble. The retina of a turtle was stimulated in vitro by moving light patterns. Its non-steady motion was specified by two features: changes of direction and changes of speed. The spike response of a ganglion cell population was recorded extracellularly with a multielectrode array and responding neurons were identified through spike sorting. Restricting further analysis to a time window of greatest firing activity, we selected a subset of cells with reliable firing patterns, excluding cells that were not selective to the stimulus. The reliability of a firing pattern was assessed on the single cell level in terms of two measures: temporal precision (jitter) of the first spike and the fraction of trials in which a spike was generated. We then condensed the spike response of the extracted group by merging the multivariate spike trains into a single spike train. Finally, we compared different coding hypotheses that are based on the timing of the first and the second spike of the population or the spike count in the preselected time window. We found that the second spike of the population significantly increases the classification efficiency beyond that of the first spike. Moreover, the combination of first plus second spike is comparably efficient as the combination of the first spike plus the spike count but allows for a classification that is much faster. PMID:19163609

  15. A population of human brain cells expressing phenotypic markers of more than one lineage can be induced in vitro to differentiate into mesenchymal cells

    International Nuclear Information System (INIS)

    Proliferating astrocytic cells from germinal, as well as mature areas of brain parenchyma, have the characteristics of neural stem/progenitor cells and are capable of generating both neurons and glia. We previously reported that primary fetal human brain cells, designated as Normal Human Astrocytes (NHA), expressed, in addition to GFAP, Vimentin and Nestin, low levels of βIII-Tubulin, an early neuronal marker, and differentiated into neurons and astrocytes in vitro. Here, we showed that primary NHA cells co-express low levels of mesenchymal markers Fibronectin and Collagen-1 in culture. These cells transitioned into mesenchymal-like cells when cultured in adherent conditions in serum containing media. The mesenchymal-like derivatives of these cells were characterized based on their morphological changes, high expression of Vimentin and extracellular matrix (ECM) proteins, Collagen-1 and Fibronectin, and decline of neural markers. When incubated in osteogenic and adipogenic induction media, the mesenchymal-like cells differentiated into osteoblasts and adipocytes. Furthermore, NHA cells express markers of neural crest cells, SOX-10 and p75. These data support the idea of ectoderm-derived mesenchymal lineages. These findings suggest that a population of primitive fetal brain cells with neural/neural crest/mesenchymal phenotype, resembles the remarkable phenotypic plasticity of neural crest cells, and differentiates into adipocytes and osteocytes under the influence of environmental factors

  16. 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

  17. Emodin as an effective agent in targeting cancer stem-like side population cells of gallbladder carcinoma.

    Science.gov (United States)

    Li, Xin-xing; Dong, Ying; Wang, Wei; Wang, Hao-lu; Chen, Yu-ying; Shi, Gui-ying; Yi, Jing; Wang, Jian

    2013-02-15

    Side population (SP) cells are previously identified from bone marrow based on their capacity to efflux of the fluorescent dye Hoechst 33342. Recent studies demonstrate that SP cells isolated from various cancer cell lines and primary tumors possess stem-cell-like properties. Thus, targeting tumor SP cells may provide new strategies for treatment in clinic. We previously showed that 1,3,8-trihydroxy-6-methylanthraquinone (emodin), a reactive oxygen species (ROS) generator, enhanced sensitivity of gallbladder cancer SGC-996 cells to cisplatin (CDDP) via generation of ROS and downregulation of multidrug-resistance-associated protein 1 (MRP1). To determine whether emodin also acts effectively on cancer stem cells of gallbladder carcinoma, we use SP cells as a model of cancer stem-cell-like cells. Here, we found that emodin, via ROS-related mechanism and suppressing the function of ATP-binding cassette super-family G member (ABCG2), which is known to be associated with Hoechst dye efflux activity of SP cells, not only reduced the ratio, inhibited clone formation, and eliminated sphere formation of SP cells effectively, but also promoted obviously the intracellular accumulation of doxorubicin, the main substrate of the efflux pump ABCG2. In addition, emodin could sensitize CDDP, via inhibition of expression of ABCG2, to overcome chemoresistance of SP cells. Importantly, similar to the experiment in vitro, emodin/CDDP co-treatment in vivo suppressed the tumor growth derived from SP cells through downregulating ABCG2 expression. Our results suggest that emodin is an effective agent targeting cancer stem-like SP cells of gallbladder carcinoma, either alone or acts as a chemotherapy enhancer. PMID:22974371

  18. Resolvability in Circulant Graphs

    Institute of Scientific and Technical Information of China (English)

    Muhammad SALMAN; Imran JAVAID; Muhammad Anwar CHAUDHRY

    2012-01-01

    A set W of the vertices of a connected graph G is called a resolving set for G if for every two distinct vertices u,v ∈ V(G) there is a vertex w ∈ W such that d(u,w) ≠ d(v,w).A resolving set of minimum cardinality is called a metric basis for G and the number of vertices in a metric basis is called the metric dimension of G,denoted by dim(G).For a vertex u of G and a subset S of V(G),the distance between u and S is the number mins∈s d(u,s).A k-partition H ={S1,S2,...,Sk} of V(G) is called a resolving partition if for every two distinct vertices u,v ∈ V(G) there is a set Si in Π such that d(u,Si) ≠ d(v,Si).The minimum k for which there is a resolving k-partition of V(G) is called the partition dimension of G,denoted by pd(G).The circulant graph is a graph with vertex set Zn,an additive group ofintegers modulo n,and two vertices labeled i and j adjacent if and only if i - j (mod n) ∈ C,where C C Zn has the property that C =-C and 0(∈) C.The circulant graph is denoted by Xn,△ where A =|C|.In this paper,we study the metric dimension of a family of circulant graphs Xn,3 with connection set C ={1,-n/2,n - 1} and prove that dim(Xn,3) is independent of choice of n by showing that 3 for all n =0 (mod 4),dim(X,n,3) ={ 4 for all n =2 (mod 4).We also study the partition dimension of a family of circulant graphs Xn,4 with connection set C ={±1,±2} and prove that pd(Xn,4) is independent of choice of n and show that pd(X5,4) =5 and 3 forall odd n≥9,pd(Xn,4) ={ 4 for all even n ≥ 6 and n =7.

  19. Dual Brushless Resolver Rate Sensor

    Science.gov (United States)

    Howard, David E. (Inventor)

    1997-01-01

    A resolver rate sensor is disclosed in which dual brushless resolvers are mechanically coupled to the same output shaft. Diverse inputs are provided to each resolver by providing the first resolver with a DC input and the second resolver with an AC sinusoidal input. A trigonometric identity in which the sum of the squares of the sin and cosine components equal one is used to advantage in providing a sensor of increased accuracy. The first resolver may have a fixed or variable DC input to permit dynamic adjustment of resolver sensitivity thus permitting a wide range of coverage. In one embodiment of the invention the outputs of the first resolver are directly inputted into two separate multipliers and the outputs of the second resolver are inputted into the two separate multipliers, after being demodulated in a pair of demodulator circuits. The multiplied signals are then added in an adder circuit to provide a directional sensitive output. In another embodiment the outputs from the first resolver is modulated in separate modulator circuits and the output from the modulator circuits are used to excite the second resolver. The outputs from the second resolver are demodulated in separate demodulator circuit and added in an adder circuit to provide a direction sensitive rate output.

  20. Human Embryonic St me Cell Lines fromthe Chinese Population and Differentiation to Liver and Muscle Cell Types

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    We have established 6 hES cell lines from IVF surplus blastocysts. Characterization of these lines have shown that 4 of the 6 lines meet all of the criterion (Science) for hES cell lines and 2 of them display most characteristics of hES cells but do not form teratoma. In order to produce hES cell lines without using mouse feeders, we have produced a hES cell line using feeders derived from hES cells themselves, and showed that hES-derived feeders are capable of supporting the derivation of new hES cell line...

  1. Large scale analysis of pediatric antiviral CD8+ T cell populations reveals sustained, functional and mature responses

    Directory of Open Access Journals (Sweden)

    Northfield John

    2006-12-01

    Full Text Available Abstract Background Cellular immunity plays a crucial role in cytomegalovirus (CMV infection and substantial populations of CMV-specific T cells accumulate throughout life. However, although CMV infection occurs during childhood, relatively little is know about the typical quantity and quality of T cell responses in pediatric populations. Methods One thousand and thirty-six people (Male/Female = 594/442, Age: 0–19 yr.; 959 subjects, 20–29 yr.; 77 subjects were examined for HLA typing. All of 1036 subjects were tested for HLA-A2 antigen. Of 1036 subjects, 887 were also tested for HLA-A23, 24 antigens. In addition, 50 elderly people (Male/Female = 11/39, Age: 60–92 yr. were also tested for HLA-A2 antigen. We analyzed the CD8+ T cell responses to CMV, comparing these to responses in children and young. The frequencies, phenotype and function CD8+ T cells for two imunodominant epitopes from pp65 were measured. Results We observed consistently high frequency and phenotypically "mature" (CD27 low, CD28 low, CD45RA+ CMV-specific CD8+ T cell responses in children, including those studied in the first year of life. These CD8+ T cells retained functionality across all age groups, and showed evidence of memory "inflation" only in later adult life. Conclusion CMV consistently elicits a very strong CD8+ T cell response in infants and large pools of CMV specific CD8+ T cells are maintained throughout childhood. The presence of CMV may considerably mould the CD8+ T cell compartment over time, but the relative frequencies of CMV-specific cells do not show the evidence of a population-level increase during childhood and adulthood. This contrast with the marked expansion ("inflation" of such CD8+ T cells in older adults. This study indicates that large scale analysis of peptide specific T cell responses in infants is readily possible. The robust nature of the responses observed suggests vaccine strategies aimed at priming and boosting CD8+ T cells against

  2. Ionizing irradiation not only inactivates clonogenic potential in primary normal human diploid lens epithelial cells but also stimulates cell proliferation in a subset of this population.

    Directory of Open Access Journals (Sweden)

    Yuki Fujimichi

    Full Text Available Over the past century, ionizing radiation has been known to induce cataracts in the crystalline lens of the eye, but its mechanistic underpinnings remain incompletely understood. This study is the first to report the clonogenic survival of irradiated primary normal human lens epithelial cells and stimulation of its proliferation. Here we used two primary normal human cell strains: HLEC1 lens epithelial cells and WI-38 lung fibroblasts. Both strains were diploid, and a replicative lifespan was shorter in HLEC1 cells. The colony formation assay demonstrated that the clonogenic survival of both strains decreases similarly with increasing doses of X-rays. A difference in the survival between two strains was actually insignificant, although HLEC1 cells had the lower plating efficiency. This indicates that the same dose inactivates the same fraction of clonogenic cells in both strains. Intriguingly, irradiation enlarged the size of clonogenic colonies arising from HLEC1 cells in marked contrast to those from WI-38 cells. Such enhanced proliferation of clonogenic HLEC1 cells was significant at ≥2 Gy, and manifested as increments of ≤2.6 population doublings besides sham-irradiated controls. These results suggest that irradiation of HLEC1 cells not only inactivates clonogenic potential but also stimulates proliferation of surviving uniactivated clonogenic cells. Given that the lens is a closed system, the stimulated proliferation of lens epithelial cells may not be a homeostatic mechanism to compensate for their cell loss, but rather should be regarded as abnormal. This is because these findings are consistent with the early in vivo evidence documenting that irradiation induces excessive proliferation of rabbit lens epithelial cells and that suppression of lens epithelial cell divisions inhibits radiation cataractogenesis in frogs and rats. Thus, our in vitro model will be useful to evaluate the excessive proliferation of primary normal human lens

  3. Identification of ataxia telangiectasia heterozygotes, a cancer-prone population, using the single-cell gel electrophoresis (Comet) assay.

    Science.gov (United States)

    Djuzenova, C S; Schindler, D; Stopper, H; Hoehn, H; Flentje, M; Oppitz, U

    1999-06-01

    Heterozygotes of ataxia telangiectasia (AT) may comprise up to 1% of the general population. Because these individuals have no clinical expression of AT but may be highly radiosensitive and strongly predisposed for several forms of cancer, identification of AT carriers represents a considerable interest in cancer epidemiology and radiotherapy. We report a new approach for the in vitro identification of AT-heterozygotes based on the evaluation of the radiosensitivity and DNA damage repair ability of peripheral blood mononuclear cells using the single-cell gel electrophoresis (Comet) assay. The assay was performed on cells isolated from four different groups of individuals: (1) apparently healthy donors (n = 10); (2) patients with breast cancer showing a normal reaction to radiotherapy (n = 10); (3) a group of obligate AT carriers (parents of AT-homozygotes, n = 20); and (4) AT-homozygotes (n = 4). Cells irradiated with 3 Gy of x-rays were assayed for three parameters: (1) the initial and (2) residual DNA damage and (3) the kinetics of DNA damage repair. Both AT-heterozygotes' and AT-homozygotes' cells were found to be highly sensitive to x-irradiation. Quantitative evaluation of the single-cell electrophoregrams revealed that the average initial DNA damage in AT-heterozygous and AT-homozygous cells was almost three times higher than that in control non-AT cells. In addition, the DNA repair process in irradiated AT carrier cells was almost three times slower, and the extent of irreparable DNA damage in these cells was three times greater than in controls. Simultaneous assessment of the three parameters enabled correct identification of all tested AT carriers. This method seems to be a sensitive and useful tool for populational studies as a rapid prescreening test for a mutated AT status. The approach can also be extended for prediction of the in vivo radiosensitivity, which would enable optimization of individual radiotherapy schedules. PMID:10378512

  4. 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.

  5. Distribution specificity of polarized populations of T helper cells in patients with chronic hepatitis B virus infection

    Institute of Scientific and Technical Information of China (English)

    JIANG Rong-long; FENG Xiao-rong; LU Qiao-sheng; LUO Kang-xian; FU Ning

    2001-01-01

    Objective: To investigate the roles of the polarized populations of T helper cells isolated from the peripheral blood mononuclear cells (PBMCs) of individuals with chronic hepatitis B virus (HBV) infection. Methods: PBMCs from patients with chronic HBV infection were separated routinely, stimulated by PMA, ionomycin and monensin, and the production of IL-4, IFN-γ and TGF-β by CD4+ T cells was observed by flow cytometry(FACS). Results: The percentages of the T cells producing IFN-γ, IL-4 or TGF-β ranged from 2.3% to 18.6%, 1.1% to 8.7% and 0.7% to 7.1% respectively among CD4+ cells from non-infected individuals. The majority of CD4+ T cells in PBMCs from individuals with chronic HBV infection were Th0 cells. The proportion of Th1 cells in patients with active chronic hepatitis B was higher than that in patients at inactive stage of the disease (P<0.05), indicating a significant elevation of Thl cells with the hepatic inflammation activity. The percentage of Th2 cells in individuals with HBV infection was higher than that in controls (P<0.05),but showed no difference between different patients (P>0.05). The percentage of Th3 cells was higher in asymptomatic HBV carriers than that in patients with chronic hepatitis B and in healthy controls (P<0.05). Conclusions: Th1-type cytokines are related with hepatic inflammation activity of chronic hepatitis B, and Th2 cells may be associated with the persistence of HBV infection. Th3 cells cooperating with Th2 cells are likely to function as negative immunoregulator, and may be responsible for the immune tolerance state of chronic HBV infection.

  6. Ankylosing spondylitis patients display altered dendritic cell and T cell populations that implicate pathogenic roles for the IL-23 cytokine axis and intestinal inflammation

    OpenAIRE

    Wright, Pamela B.; McEntegart, Anne; McCarey, David; McInnes, Iain B.; Siebert, Stefan; Milling, Simon W F

    2015-01-01

    Objective. AS is a systemic inflammatory disease of the SpA family. Polymorphisms at loci including HLA-B27, IL-23R and ERAP-1 directly implicate immune mechanisms in AS pathogenesis. Previously, in an SpA model, we identified HLA-B27–mediated effects on dendritic cells that promoted disease-associated Th17 cells. Here we extend these studies to AS patients using deep immunophenotyping of candidate pathogenic cell populations. The aim of our study was to functionally characterize the immune p...

  7. Cell Wall Composition and Underlying QTL in an F1 Pseudo-Testcross Population of Switchgrass

    Energy Technology Data Exchange (ETDEWEB)

    Serba, Desalegn D.; Sykes, Robert W.; Gjersing, Erica L.; Decker, Stephen R.; Daverdin, Guillaume; Devos, Katrien M.; Brummer, E. Charles; Saha, Malay C.

    2016-09-01

    Natural genetic variation for reduced recalcitrance can be used to improve switchgrass for biofuel production. A full-sib switchgrass mapping population developed by crossing a lowland genotype, AP13, and upland genotype, VS16, was evaluated at three locations (Ardmore and Burneyville, OK and Watkinsville, GA). Biomass harvested after senescence in 2009 and 2010 was evaluated at the National Renewable Energy Laboratory (NREL) for sugar release using enzymatic hydrolysis and for lignin content and syringyl/guaiacyl lignin monomer (S/G) ratio using pyrolysis molecular beam mass spectrometry (py-MBMS). Glucose and xylose release ranged from 120 to 313 and 123 to 263 mg g-1, respectively, while lignin content ranged from 19 to 27% of the dry biomass. Statistically significant differences were observed among the genotypes and the environments for the cell wall composition traits. Regression analysis showed that a unit increase in lignin content reduced total sugar release by an average of 10 mg g-1. Quantitative trait loci (QTL) analysis detected 9 genomic regions underlying sugar release and 14 for lignin content. The phenotypic variation explained by the individual QTL identified for sugar release ranged from 4.5 to 9.4 and for lignin content from 3.8 to 11.1%. Mapping of the QTL regions to the switchgrass genome sequence (v1.1) found that some of the QTL colocalized with genes involved in carbohydrate processing and metabolism, plant development, defense systems, and transcription factors. The markers associated with QTL can be implemented in breeding programs to efficiently develop improved switchgrass cultivars for biofuel production.

  8. Cell-cycle protein expression in a population-based study of ovarian and endometrial cancers

    Directory of Open Access Journals (Sweden)

    Ashley S. Felix

    2015-02-01

    Full Text Available Aberrant expression of cyclin-dependent kinase (CDK inhibitors is implicated in the carcinogenesis of many cancers, including ovarian and endometrial cancers. We examined associations between CDK inhibitor expression, cancer risk factors, tumor characteristics, and survival outcomes among ovarian and endometrial cancer patients enrolled in a population-based case control study. Expression (negative vs. positive of three CDK inhibitors (p16, p21, p27 and ki67 was examined with immunohistochemical staining of tissue microarrays. Logistic regression was used to estimate adjusted odds ratios (ORs and 95% confidence intervals (CIs for associations between biomarkers, risk factors, and tumor characteristics. Survival outcomes were available for ovarian cancer patients and examined using Kaplan-Meier plots and Cox proportional hazards regression. Among ovarian cancer patients (n=175, positive p21 expression was associated with endometrioid tumors (OR=12.22, 95% CI=1.45-102.78 and higher overall survival (log-rank p=0.002. In Cox models adjusted for stage, grade, and histology, the association between p21 expression and overall survival was borderline significant (hazard ratio=0.65, 95% CI=0.42-1.05. Among endometrial cancer patients (n=289, positive p21 expression was inversely associated with age (OR ≥ 65 years of age=0.25, 95% CI=0.07-0.84 and current smoking status (OR: 0.33, 95% CI 0.15, 0.72 compared to negative expression. Our study showed heterogeneity in expression of cell-cycle proteins associated with risk factors and tumor characteristics of gynecologic cancers. Future studies to assess these markers of etiological classification and behavior may be warranted.

  9. Cell-cycle protein expression in a population-based study of ovarian and endometrial cancers.

    Science.gov (United States)

    Felix, Ashley S; Sherman, Mark E; Hewitt, Stephen M; Gunja, Munira Z; Yang, Hannah P; Cora, Renata L; Boudreau, Vicky; Ylaya, Kris; Lissowska, Jolanta; Brinton, Louise A; Wentzensen, Nicolas

    2015-01-01

    Aberrant expression of cyclin-dependent kinase (CDK) inhibitors is implicated in the carcinogenesis of many cancers, including ovarian and endometrial cancers. We examined associations between CDK inhibitor expression, cancer risk factors, tumor characteristics, and survival outcomes among ovarian and endometrial cancer patients enrolled in a population-based case-control study. Expression (negative vs. positive) of three CDK inhibitors (p16, p21, and p27) and ki67 was examined with immunohistochemical staining of tissue microarrays. Logistic regression was used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for associations between biomarkers, risk factors, and tumor characteristics. Survival outcomes were only available for ovarian cancer patients and examined using Kaplan-Meier plots and Cox proportional hazards regression. Among ovarian cancer patients (n = 175), positive p21 expression was associated with endometrioid tumors (OR = 12.22, 95% CI = 1.45-102.78) and higher overall survival (log-rank p = 0.002). In Cox models adjusted for stage, grade, and histology, the association between p21 expression and overall survival was borderline significant (hazard ratio = 0.65, 95% CI = 0.42-1.05). Among endometrial cancer patients (n = 289), positive p21 expression was inversely associated with age (OR ≥ 65 years of age = 0.25, 95% CI = 0.07-0.84) and current smoking status (OR: 0.33, 95% CI 0.15, 0.72) compared to negative expression. Our study showed heterogeneity in expression of cell-cycle proteins associated with risk factors and tumor characteristics of gynecologic cancers. Future studies to assess these markers of etiological classification and behavior may be warranted. PMID:25709969

  10. Imposing resolved turbulence in CFD simulations

    DEFF Research Database (Denmark)

    Gilling, L.; Sørensen, Niels N.

    2011-01-01

    In large‐eddy simulations, the inflow velocity field should contain resolved turbulence. This paper describes and analyzes two methods for imposing resolved turbulence in the interior of the domain in Computational Fluid Dynamics simulations. The intended application of the methods is to impose...... resolved turbulence immediately upstream of the region or structure of interest. Comparing to the alternative of imposing the turbulence at the inlet, there is a large potential to reduce the computational cost of the simulation by reducing the total number of cells. The reduction comes from a lower demand...... modifying the source terms. None of the two methods can impose synthetic turbulence with good results, but it is shown that by running the turbulence field through a short precursor simulation, very good results are obtained. Copyright © 2011 John Wiley & Sons, Ltd....

  11. Cellular morphometry and cycling cell populations of human and dog bronchi. Final report, April 1, 1988 - December 31, 1996

    International Nuclear Information System (INIS)

    Quantitative data of the human bronchial epithelial cells at possible risk for malignant transformation in lung cancer is crucial for accurate radon dosimetry and risk analysis. The locations and other parameters of the nuclei which may be damaged by α particles and develop into cancers have been determined and compared in different airway generations, among smokers, non-smokers and ex-smokers, between men and women and in people of different ages. This research included extended morphometric studies on electron micrographs of human epithelium of defined airway generations. Since cycling cells can be more sensitive to damage from carcinogens and radioactivity, a second major part of this research consisted of studies to quantitate the cycling tracheobronchial epithelial population(s) using immunocytochemistry and the proliferation marker PCNA on paraffin sections. The basal and suprabasal cycling cell populations of the bronchi of smokers, non-smokers, and ex-smokers, men and women were compared. Normal human airway linings were also compared with normal adult dog trachea and bronchi as well as metaplastic and repairing human airways. The quantitative data from this project resulted in several publications on the cycling and putative stem cells of the tracheobronchial epithelium and more accurate radon dosimetry and risk analyses

  12. Coal to gas single cell protein-contribute to resolving the food crisis of China in future%中国城市化进程中的粮食安全与风/煤制天然气单细胞蛋白的研究

    Institute of Scientific and Technical Information of China (English)

    曹晨; 余波; 顾为东

    2015-01-01

    据预测2030年我国人口将会达到峰值14.5亿,城市化率达到70%,届时城市人口新增3亿,总数将超过10亿。随着总人口的持续增加以及城市人口的迅速膨胀,我国未来将会面临严峻的粮食不足问题,尤其以蛋白质为代表的营养物质将会出现严重短缺。本文针对这一问题,提出了以风力发电为能源,以煤制天然气为原料的单细胞蛋白制备新思路,新途径。此方法通过煤制天然气生产单细胞蛋白,既解决了传统煤炭利用中碳排放高、环境负荷大等缺点,实现了煤炭的升级、绿色利用,又解决了利用石油、工农业废弃物生产单细胞蛋白所产生的食品安全性等问题。另外,此方法可实现大规模工业化生产,为解决我国未来蛋白质不足提供一条绿色、高效、切实可行的新途径。%It is predicted that the population of China will be growing to 1.45 billion,the ur-banization rate will be 70%by 2030,the total urban population will be exploded to 1 billion comparing with 0.7 billion urban population of 2013. As the continuously growing of popula-tion of China and urban population,China will face severe food crisis,especially the protein shortage problem in future. This paper presents a new theoretical model that by combining non-grid-connected wind power and coal to gas with bioengineering to produce single cell protein to contribute to resolving the food crisis. By combining non-grid-connected wind power and coal to gas with bioengineering to produce single cell protein can not only use the coal resource more efficiently,environmental friendly,but also produce nutrient rich protein for forage and human food.

  13. Charge dynamics at heterojunctions for PbS/ZnO colloidal quantum dot solar cells probed with time-resolved surface photovoltage spectroscopy

    Science.gov (United States)

    Spencer, B. F.; Leontiadou, M. A.; Clark, P. C. J.; Williamson, A. I.; Silly, M. G.; Sirotti, F.; Fairclough, S. M.; Tsang, S. C. E.; Neo, D. C. J.; Assender, H. E.; Watt, A. A. R.; Flavell, W. R.

    2016-02-01

    Time-resolved laser-pump X-ray-photoemission-probe spectroscopy of a ZnO ( 10 1 ¯ 0 ) substrate with and without PbS quantum dots (QDs) chemically linked to the surface is performed, using laser photon energies resonant with and below the band gap energy of the substrate (λ = 372 and 640 nm, hν = 3.33 and 1.94 eV). Charge injection from the photoexcited QDs to ZnO is demonstrated through the change in the surface photovoltage of the ZnO substrate observed when the heterojunction is illuminated with 1.94 eV radiation. The measured carrier dynamics are limited by the persistent photoconductivity of ZnO, giving dark carrier lifetimes of the order of 200 μs in a depletion layer at the interface. The chemical specificity of soft X-rays is used to separately measure the charge dynamics in the quantum dots and the substrate, yielding evidence that the depletion region at the interface extends into the PbS QD layer.

  14. Distinct populations of dendritic cells are present in the subepithelial dome and T cell regions of the murine Peyer's patch

    Science.gov (United States)

    1996-01-01

    Despite the fact that the Peyer's patch (PP) is the primary site for antigen uptake in the intestine, the cellular basis of antigen handling after transport into the PP is poorly understood. We performed immunohistology of murine PPs using the dendritic cell (DC)-reactive monoclonal antibodies N418, NLDC-145, M342, and 2A1, as well as antibodies to other T cell, B cell, and macrophage markers. N418+, 2A1+, NLDC-145-, M342- cells form a dense layer of cells in the subepithelial dome (SED), just beneath the follicle epithelium, and are scattered throughout the follicle, sparing the germinal center. In contrast, N418+, 2A1+, NLDC-145+, and M342+ DCs are present in the interfollicular T cell regions (IFR). CD3+ and CD4+, but no CD8+ T cells were present in the SED and the follicle, including the germinal center, while CD3+, CD4+, and CD8+ T cells were present in the IFR. B cells and macrophages were poorly represented in the SED as no B220+ cells, only few Mac-1lo cells, and no F4/80+ cells were present at this site. In contrast, Mac-1hi cells were found in the IFR and lamina propria of intestinal villi, while F4/80+ cells were found only in the latter. In further phenotypic studies, we analyzed surface molecules of PP and spleen DCs by flow cytometry and found that these cells had similar fluorescence profiles when stained with N418, NLDC-145, and 33D1 DC-reactive antibodies, and antibodies to the costimulatory molecules B7-1 (1G10) and B7-2 (GL1). In contrast, PP DCs expressed 5- 10-fold higher levels of major histocompatibility complex class II antigens (IEk) than spleen DCs. Finally, in functional studies, we demonstrated that both PP and spleen DCs process soluble protein antigens during overnight culture and induce similar levels of proliferation in CD3+ T cells, and CD4+/Mel 14hi T cells from T cell receptor transgenic mice. The in vivo relevance of such presentation was shown by the fact that PP DCs isolated from Balb/c mice after being fed ovalbumin stimulated

  15. Hematopoietic Stem Cell Transplantation in Thalassemia and Sickle Cell Disease. Unicenter Experience in a Multi-Ethnic Population.

    OpenAIRE

    Marziali, Marco; Isgrò, Antonella; Gaziev, Javid; Lucarelli, Guido

    2009-01-01

    Hematopoietic stem cell transplantation (HSCT) still remains the only definitive cure currently available for patients with thalassemia and sickle cell anemia. Results of transplant in thalassemia and in sickle cell anemia have steadily improved over the last two decades due to improvements in preventive strategies, and effective control of transplant-related complications. From 2004 through 2009, 145 consecutive patients with thalassemia and sickle cell anemia, ethnically heterogeneous from ...

  16. Georges Bank conflict resolved

    Science.gov (United States)

    Robb, David W.

    1984-04-01

    The International Court of Justice has resolved the long-term conflict between the United States and Canada over claims to mineral and living resources lying along the countries' common Atlantic maritime border. On October 12, in a 4-1 decision, the World Court rejected the United States' claim to the entire Georges Bank area, a region of the Continental Shelf off Massachusetts and Nova Scotia that is a prime fishing ground and is believed to have good potential for oil and gas deposits as well. The disputed area is roughly the top third of the Georges Bank area. The court awarded each country approximately half of this disputed area. No appeals are allowed under this decision.

  17. Population transcriptomics with single-cell resolution: a new field made possible by microfluidics: a technology for high throughput transcript counting and data-driven definition of cell types.

    Science.gov (United States)

    Plessy, Charles; Desbois, Linda; Fujii, Teruo; Carninci, Piero

    2013-02-01

    Tissues contain complex populations of cells. Like countries, which are comprised of mixed populations of people, tissues are not homogeneous. Gene expression studies that analyze entire populations of cells from tissues as a mixture are blind to this diversity. Thus, critical information is lost when studying samples rich in specialized but diverse cells such as tumors, iPS colonies, or brain tissue. High throughput methods are needed to address, model and understand the constitutive and stochastic differences between individual cells. Here, we describe microfluidics technologies that utilize a combination of molecular biology and miniaturized labs on chips to study gene expression at the single cell level. We discuss how the characterization of the transcriptome of each cell in a sample will open a new field in gene expression analysis, population transcriptomics, that will change the academic and biomedical analysis of complex samples by defining them as quantified populations of single cells. PMID:23281054

  18. A novel population of local pericyte precursor cells in tumor stroma that require Notch signaling for differentiation.

    Science.gov (United States)

    Patenaude, Alexandre; Woerher, Stefan; Umlandt, Patricia; Wong, Fred; Ibrahim, Rawa; Kyle, Alastair; Unger, Sandy; Fuller, Megan; Parker, Jeremy; Minchinton, Andrew; Eaves, Connie J; Karsan, Aly

    2015-09-01

    Pericytes are perivascular support cells, the origin of which in tumor tissue is not clear. Recently, we identified a Tie1(+) precursor cell that differentiates into vascular smooth muscle, in a Notch-dependent manner. To understand the involvement of Notch in the ontogeny of tumor pericytes we used a novel flow immunophenotyping strategy to define CD146(+)/CD45(-)/CD31(-/lo) pericytes in the tumor stroma. This strategy combined with ex vivo co-culture experiments identified a novel pericyte progenitor cell population defined as Sca1(hi)/CD146(-)/CD45(-)/CD31(-). The differentiation of these progenitor cells was stimulated by co-culture with endothelial cells. Overexpression of the Notch ligand Jagged1 in endothelial cells further stimulated the differentiation of Sca1(hi)/CD146(-)/CD45(-)/CD31(-) cells into pericytes, while inhibition of Notch signaling with a γ-secretase inhibitor reduced this differentiation. However, Notch inhibition specifically in Tie1-expressing cells did not change the abundance of pericytes in tumors, suggesting that the pericyte precursor is distinct from the vascular smooth muscle cell precursor. Transplant experiments showed that the bone marrow contributes minimally to tumor pericytes. Immunophenotyping revealed that Sca1(hi)/CD146(-)/CD45(-)/CD31(-) cells have greater potential to differentiate into pericytes and have increased expression of classic mesenchymal stem cell markers (CD13, CD44, Nt5e and Thy-1) compared to Sca1(-/lo)/CD146(-)/CD45(-)/CD31(-) cells. Our results suggest that a local Sca1(hi)/CD146(-)/CD45(-)/CD31(-) pericyte progenitor resides in the tumor microenvironment and requires Notch signaling for differentiation into mature pericytes. PMID:26092680

  19. Natural killer cell (NK) subsets and NK-like T-cell populations in acute myeloid leukemias and myelodysplastic syndromes.

    Science.gov (United States)

    Aggarwal, N; Swerdlow, S H; TenEyck, S P; Boyiadzis, M; Felgar, R E

    2016-07-01

    The impact of the immune microenvironment on the behavior and therapeutic strategies for hematopoietic and lymphoid neoplasms is being increasingly recognized. Many functional studies of natural killer (NK) cell cytotoxic responses in myelodysplasia (MDS) and acute myeloid leukemia (AML) exist, but with limited data on these lymphocyte proportions and related T-cell subsets. The proportions of these cells and their prognostic implications were therefore investigated in 89 AML, 51 MDS, and 20 control marrows by flow cytometry. The median proportion of NK cells (relative to the total lymphocytes) was lower in AML versus controls (P = 0.01). Among AML, a lower proportion of NK cells predicted better survival, whereas a higher NK cell proportion was associated with the poor prognostic AML category (P = 0.002). NK cell proportions were similar in MDS, MDS subgroups, and control marrows. The relative proportion of the mature NK cell subset (CD56(dim) CD16/57(bright) ) was lower in AML and MDS versus controls (P = 0.006, P = 0.0002, respectively). The proportion of mature NK cells was not a prognostic indicator although fewer were seen in poor prognosis AML. In contrast, a lower proportion of mature NK cells correlated with worse survival in MDS (P = 0.027). A higher proportion of NK-like T-cells (of total lymphoid cells) was found in MDS compared to controls (P = 0.01). A lower proportion of NK-like T-cells predicted better survival in AML but not in MDS. Thus, the proportions of NK, NK-cell subsets, and NK-like T-cells vary in myeloid neoplasms, may potentially impact immunomodulatory therapies, and may impact outcome. © 2016 International Clinical Cytometry Society. PMID:26648320

  20. Transcriptional and functional differences in stem cell populations isolated from Extraocular and Limb muscles

    DEFF Research Database (Denmark)

    Pacheco-Pinedo, Eugenia Cristina; Budak, Murat T; Zeiger, Ulrike;

    2008-01-01

    and is consistent with a role for their sparing in DMD . We believe the greater numbers of stem cells, their unique transcriptome, the greater proliferative capacity of EOM stem cells and greater number of satellite cells also offers clues for novel cell-based therapeutic strategies. Key words: Side...... capacity. Finally, assays of the committed progenitors or satellite cells performed on myofibers isolated from EOM and limb muscles independently validated increased proliferative capacity of these muscles. We suggest a model wherein unique EOM stem cells contribute to the continual myogenesis noted in EOM...

  1. Different mouse mast cell populations express various combinations of at least six distinct mast cell serine proteases.

    OpenAIRE

    Reynolds, D. S.; Stevens, R L; Lane, W S; Carr, M H; Austen, K. F.; Serafin, W E

    1990-01-01

    Mouse serosal mast cells (SMCs) and Kirsten sarcoma virus-immortalized mast cells store large amounts of mast cell carboxypeptidase A and serine proteases in their secretory granules. Secretory granule proteins from 2.6 x 10(6) purified SMCs were separated by NaDodSO4/PAGE, trans-blotted to poly(vinylidine difluoride) membranes, and subjected to amino-terminal amino acid sequencing. Four distinct mast cell serine proteases were identified. With mast cell carboxypeptidase A, these serine prote...

  2. Cell population kinetics and dose-time relationships for post-irradiation injury of the brachial plexus in man

    International Nuclear Information System (INIS)

    Collected data on radiation-induced lesions of the brachial plexus were analyzed on the assuption that this reaction arises from depletion of some unidentified cell population in the irradiated tissues. A multi-probit search program was used to derive best-fitting cell kinetic parameters in a composite multi-target model for cellular radiation lethality and repopulation. From these parameters, a comprehensive iso-effect table, for a wide range of treatment schedules including daily treatment as well as fractionation at shorter and longer intervals, was constructed. The table provides a useful set of tolerance dosage limits for late effects in irradiation peripheral nerve. (Auth.)

  3. Exposure to sun radiation as a risk factor for the occurrence of basal cell carcinoma in the Montenegrian population

    OpenAIRE

    Maksimović Nataša; Ražnatović Milena; Marinković Jelena; Janković Janko

    2006-01-01

    Backgound/aim: Basal cell carcinoma (BCC) is the most frequent form of carcinomas in the whites. Among the environmental factors, the most important risk factor for its occurrence is the exposure to sun radiation. The aim of this study was to assess the role of the sun radiation in the development of basal cell carcinoma BCC in the Montenegrian population. Methods. A case-control study was conducted in a period from 2002-2003. The study group included 100 histopatologically confirmed cases wi...

  4. Tcf3 Represses Wnt–β-Catenin Signaling and Maintains Neural Stem Cell Population during Neocortical Development

    OpenAIRE

    Kuwahara, Atsushi; Sakai, Hiroshi; Xu, Yuanjiang; Itoh, Yasuhiro; Hirabayashi, Yusuke; Gotoh, Yukiko

    2014-01-01

    During mouse neocortical development, the Wnt–β-catenin signaling pathway plays essential roles in various phenomena including neuronal differentiation and proliferation of neural precursor cells (NPCs). Production of the appropriate number of neurons without depletion of the NPC population requires precise regulation of the balance between differentiation and maintenance of NPCs. However, the mechanism that suppresses Wnt signaling to prevent premature neuronal differentiation of NPCs is poo...

  5. Simultaneous confidence intervals for the population cell means, for two-by-two factorial data, that utilize uncertain prior information

    OpenAIRE

    Kabaila, Paul; Giri, Khageswor

    2008-01-01

    Consider a two-by-two factorial experiment with more than 1 replicate. Suppose that we have uncertain prior information that the two-factor interaction is zero. We describe new simultaneous frequentist confidence intervals for the 4 population cell means, with simultaneous confidence coefficient 1-alpha, that utilize this prior information in the following sense. These simultaneous confidence intervals define a cube with expected volume that (a) is relatively small when the two-factor interac...

  6. Molecular and Bioenergetic Differences between Cells with African versus European Inherited Mitochondrial DNA Haplogroups: Implications for Population Susceptibility to Diseases

    OpenAIRE

    Kenney, M Cristina; Chwa, Marilyn; Atilano, Shari R.; Falatoonzadeh, Payam; Ramirez, Claudio; Malik, Deepika; Tarek, Mohamed; Cáceres del Carpio, Javier; Nesburn, Anthony B.; Boyer, David S.; Baruch D Kuppermann; Vawter, Marquis P.; Jazwinski, S. Michal; Miceli, Michael V.; Wallace, Douglas C.

    2013-01-01

    The geographic origins of populations can be identified by their maternally inherited mitochondrial DNA (mtDNA) haplogroups. This study compared human cybrids (cytoplasmic hybrids), which are cell lines with identical nuclei but mitochondria from different individuals with mtDNA from either the H haplogroup or L haplogroup backgrounds. The most common European haplogroup is H while individuals of maternal African origin are of the L haplogroup. Despite lower mtDNA copy numbers,...

  7. Nuclear pockets and clefts in the lymphoid cell population of bone marrow and blood of children with acute lymphoblastic leukemia.

    OpenAIRE

    Schuurmans Stekhoven, J. H.; Holland, R.

    1986-01-01

    Ultrastructural investigation of the nuclei of the lymphoid cell population of bone marrow and blood of children with acute lymphoblastic leukemia regularly shows the presence of two types of nuclear pockets and nuclear clefts. The incidences of these nuclear features decrease significantly during cytostatic therapy. The pockets consist of either a cytoplasmic segment enclosed by a nuclear heterochromatin bridge or a nuclear segment enclosed by an intranuclear cleft. One type of nuclear cleft...

  8. The fate of chrysotile-induced multipolar mitosis and aneuploid population in cultured lung cancer cells.

    Directory of Open Access Journals (Sweden)

    Beatriz de Araujo Cortez

    Full Text Available Chrysotile is one of the six types of asbestos, and it is the only one that can still be commercialized in many countries. Exposure to other types of asbestos has been associated with serious diseases, such as lung carcinomas and pleural mesotheliomas. The association of chrysotile exposure with disease is controversial. However, in vitro studies show the mutagenic potential of chrysotile, which can induce DNA and cell damage. The present work aimed to analyze alterations in lung small cell carcinoma cultures after 48 h of chrysotile exposure, followed by 2, 4 and 8 days of recovery in fiber-free culture medium. Some alterations, such as aneuploid cell formation, increased number of cells in G2/M phase and cells in multipolar mitosis were observed even after 8 days of recovery. The presence of chrysotile fibers in the cell cultures was detected and cell morphology was observed by laser scanning confocal microscopy. After 4 and 8 days of recovery, only a few chrysotile fragments were present in some cells, and the cellular morphology was similar to that of control cells. Cells transfected with the GFP-tagged α-tubulin plasmid were treated with chrysotile for 24 or 48 h and cells in multipolar mitosis were observed by time-lapse microscopy. Fates of these cells were established: retention in metaphase, cell death, progression through M phase generating more than two daughter cells or cell fusion during telophase or cytokinesis. Some of them were related to the formation of aneuploid cells and cells with abnormal number of centrosomes.

  9. Quantitation and renewal of alveolar and bronchiolar cell populations of rat lungs. Changes during some pathological processes

    International Nuclear Information System (INIS)

    The various cells of alveolar and bronchiolar tissues of rat lungs were studied qualitatively and quantitatively. In physiological conditions, the renewal rate of the cell populations is low and the frequency of the various cell types is constant. This stability, especially at the level of the alveolar tissue, was also found during the latency period and the development of radiation-induced lung cancers. A particular cellular population was demonstrated: marginated leukocyte pool at the level of the pulmonary circulation. This pool was different both qualitatively and quantitatively from the leukocytes of the systemic circulation and, in physiological conditions, behaved as a cellular reservoir of monocytes chiefly re-distributed according to the body needs. In pathological conditions, its fast migration contributed to the defence of the alveolar medium. A quantitative study of the renewal of alveolar macrophages showed that under 1 p. cent of the marginated leukocyte pool is used daily to keep up this population. This fraction undergoes a maturation stage by cellular division within the endoalveolar medium. In some pathological conditions, this division can be completely inhibited

  10. Time-Resolved Visualisation of Nearly-Native Influenza A Virus Progeny Ribonucleoproteins and Their Individual Components in Live Infected Cells.

    Science.gov (United States)

    Avilov, Sergiy; Magnus, Julie; Cusack, Stephen; Naffakh, Nadia

    2016-01-01

    Influenza viruses are a global health concern because of the permanent threat of novel emerging strains potentially capable of causing pandemics. Viral ribonucleoproteins (vRNPs) containing genomic RNA segments, nucleoprotein oligomers, and the viral polymerase, play a central role in the viral replication cycle. Our knowledge about critical events such as vRNP assembly and interactions with other viral and cellular proteins is poor and could be substantially improved by time lapse imaging of the infected cells. However, such studies are limited by the difficulty to achieve live-cell compatible labeling of active vRNPs. Previously we designed the first unimpaired recombinant influenza WSN-PB2-GFP11 virus allowing fluorescent labeling of the PB2 subunit of the viral polymerase (Avilov et al., J.Virol. 2012). Here, we simultaneously labeled the viral PB2 protein using the above-mentioned strategy, and virus-encoded progeny RNPs through spontaneous incorporation of transiently expressed NP-mCherry fusion proteins during RNP assembly in live infected cells. This dual labeling enabled us to visualize progeny vRNPs throughout the infection cycle and to characterize independently the mobility, oligomerization status and interactions of vRNP components in the nuclei of live infected cells. PMID:26978069

  11. Tracking of peptide-specific CD4+ T-cell responses after an acute resolving viral infection: a study of parvovirus B19

    DEFF Research Database (Denmark)

    Kasprowicz, Victoria; Isa, Adiba; Tolfvenstam, Thomas;

    2006-01-01

    The evolution of peptide-specific CD4(+) T-cell responses to acute viral infections of humans is poorly understood. We analyzed the response to parvovirus B19 (B19), a ubiquitous and clinically significant pathogen with a compact and conserved genome. The magnitude and breadth of the CD4(+) T...

  12. Insights from a chimpanzee adipose stromal cell population: opportunities for adult stem cells to expand primate functional genomics.

    Science.gov (United States)

    Pfefferle, Lisa W; Wray, Gregory A

    2013-01-01

    Comparisons between humans and chimpanzees are essential for understanding traits unique to each species. However, linking important phenotypic differences to underlying molecular changes is often challenging. The ability to generate, differentiate, and profile adult stem cells provides a powerful but underutilized opportunity to investigate the molecular basis for trait differences between species within specific cell types and in a controlled environment. Here, we characterize adipose stromal cells (ASCs) from Clint, the chimpanzee whose genome was first sequenced. Using imaging and RNA-Seq, we compare the chimpanzee ASCs with three comparable human cell lines. Consistent with previous studies on ASCs in humans, the chimpanzee cells have fibroblast-like morphology and express genes encoding components of the extracellular matrix at high levels. Differentially expressed genes are enriched for distinct functional classes between species: immunity and protein processing are higher in chimpanzees, whereas cell cycle and DNA processing are higher in humans. Although hesitant to draw definitive conclusions from these data given the limited sample size, we wish to stress the opportunities that adult stem cells offer for studying primate evolution. In particular, adult stem cells provide a powerful means to investigate the profound disease susceptibilities unique to humans and a promising tool for conservation efforts with nonhuman primates. By allowing for experimental perturbations in relevant cell types, adult stem cells promise to complement classic comparative primate genomics based on in vivo sampling. PMID:24092797

  13. Mathematical Model Reveals the Role of Memory CD8 T Cell Populations in Recall Responses to Influenza

    Science.gov (United States)

    Zarnitsyna, Veronika I.; Handel, Andreas; McMaster, Sean R.; Hayward, Sarah L.; Kohlmeier, Jacob E.; Antia, Rustom

    2016-01-01

    The current influenza vaccine provides narrow protection against the strains included in the vaccine, and needs to be reformulated every few years in response to the constantly evolving new strains. Novel approaches are directed toward developing vaccines that provide broader protection by targeting B and T cell epitopes that are conserved between different strains of the virus. In this paper, we focus on developing mathematical models to explore the CD8 T cell responses to influenza, how they can be boosted, and the conditions under which they contribute to protection. Our models suggest that the interplay between spatial heterogeneity (with the virus infecting the respiratory tract and the immune response being generated in the secondary lymphoid organs) and T cell differentiation (with proliferation occurring in the lymphoid organs giving rise to a subpopulation of resident T cells in the respiratory tract) is the key to understand the dynamics of protection afforded by the CD8 T cell response to influenza. Our results suggest that the time lag for the generation of resident T cells in the respiratory tract and their rate of decay following infection are the key factors that limit the efficacy of CD8 T cell responses. The models predict that an increase in the level of central memory T cells leads to a gradual decrease in the viral load, and, in contrast, there is a sharper protection threshold for the relationship between the size of the population of resident T cells and protection. The models also suggest that repeated natural influenza infections cause the number of central memory CD8 T cells and the peak number of resident memory CD8 T cells to reach their plateaus, and while the former is maintained, the latter decays with time since the most recent infection.

  14. IL25 elicits a multipotent progenitor cell po