671 research outputs found

    Isolation and primary cultures of human intrahepatic bile ductular epithelium

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    A technique for the isolation of human intrahepatic bile ductular epithelium, and the establishment of primary cultures using a serum- and growth-factor-supplemented medium combined with a connective tissue substrata is described. Initial cell isolates and monolayer cultures display phenotypic characteristics of biliary epithelial cells (low molecular weight prekeratin positive; albumin, alphafetoprotein, and Factor VIII-related antigen negative). Ultrastructural features of the cultured cells show cell polarization with surface microvilli, numerous interepithelial junctional complexes and cytoplasmic intermediate prekeratin filaments. © 1988 Tissue Culture Association, Inc

    Dipolar and scalar 3^3He and 129^{129}Xe frequency shifts in mm-sized cells

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    We describe a 3^{3}He-129^{129}Xe comagnetometer operating in stemless anodically bonded cells with a 6 mm3^3 volume and a 129^{129}Xe spin coherence time of 300 sec. We use a 87^{87}Rb pulse-train magnetometer with co-linear pump and probe beams to study the nuclear spin frequency shifts caused by spin polarization of 3^{3}He. By systematically varying the cell geometry in a batch cell fabrication process we can separately measure the cell shape dependent and independent frequency shifts. We find that a certain aspect ratio of the cylindrical cell can cancel the effects of 3^3He magnetization that limit the stability of vapor-cell comagnetometers. Using this control we also observe for the first time a scalar 3^{3}He-129^{129}Xe collisional frequency shift characterized by an enhancement factor κHeXe=0.011±0.001\kappa_{\text{HeXe}} = -0.011\pm0.001.Comment: 4 pages, 4 figure

    Interactive effects between nest microclimate and nest vegetation structure confirm microclimate thresholds for Lesser Prairie-Chicken nest survival

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    Citation: Grisham, B. A., Godar, A. J., Boal, C. W., & Haukos, D. A. (2016). Interactive effects between nest microclimate and nest vegetation structure confirm microclimate thresholds for Lesser Prairie-Chicken nest survival. Condor, 118(4), 728-746. doi:10.1650/CONDOR-16-38.1The range of Lesser Prairie-Chickens (Tympanuchus pallidicinctus) spans 4 unique ecoregions along 2 distinct environmental gradients. The Sand Shinnery Oak Prairie ecoregion of the Southern High Plains of New Mexico and Texas is environmentally isolated, warmer, and more arid than the Short-Grass, Sand Sagebrush, and Mixed-Grass Prairie ecoregions in Colorado, Kansas, Oklahoma, and the northeast panhandle of Texas. Weather is known to influence Lesser Prairie-Chicken nest survival in the Sand Shinnery Oak Prairie ecoregion; regional variation may also influence nest microclimate and, ultimately, survival during incubation. To address this question, we placed data loggers adjacent to nests during incubation to quantify temperature and humidity distribution functions in 3 ecoregions. We developed a suite of a priori nest survival models that incorporated derived microclimate parameters and visual obstruction as covariates in Program MARK. We monitored 49 nests in Mixed-Grass, 22 nests in Sand Shinnery Oak, and 30 nests in Short-Grass ecoregions from 2010 to 2014. Our findings indicated that (1) the Sand Shinnery Oak Prairie ecoregion was hotter and drier during incubation than the Mixed- and Short-Grass ecoregions; (2) nest microclimate varied among years within ecoregions; (3) visual obstruction was positively associated with nest survival; but (4) daily nest survival probability decreased by 10% every half-hour when temperature was greater than 34°C and vapor pressure deficit was less than - 23 mmHg during the day (about 0600-2100 hours). Our major finding confirmed microclimate thresholds for nest survival under natural conditions across the species' distribution, although Lesser Prairie-Chickens are more likely to experience microclimate conditions that result in nest failures in the Sand Shinnery Oak Prairie ecoregion. The species would benefit from identification of thermal landscapes and management actions that promote cooler, more humid nest microclimates. © 2016 Cooper Ornithological Society

    Teaching with Big Data: Report from the 2016 Society for Neuroscience Teaching Workshop

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    As part of a series of workshops on teaching neuroscience at the Society for Neuroscience annual meetings, William Grisham and Richard Olivo organized the 2016 workshop on Teaching Neuroscience with Big Data. This article presents a summary of that workshop. Speakers provided overviews of open datasets that could be used in teaching undergraduate courses. These included resources that already appear in educational settings, including the Allen Brain Atlas (presented by Joshua Brumberg and Terri Gilbert), and the Mouse Brain Library and GeneNetwork (presented by Robert Williams). Other resources, such as NeuroData (presented by William R. Gray Roncal), and OpenFMRI, NeuroVault, and Neurosynth (presented by Russell Poldrack) have not been broadly utilized by the neuroscience education community but offer obvious potential. Finally, William Grisham discussed the iNeuro Project, an NSF-sponsored effort to develop the necessary curriculum for preparing students to handle Big Data. Linda Lanyon further elaborated on the current state and challenges in educating students to deal with Big Data and described some training resources provided by the International Neuroinformatics Coordinating Facility. Neuroinformatics is a subfield of neuroscience that deals with data utilizing analytical tools and computational models. The feasibility of offering neuroinformatics programs at primarily undergraduate institutions was also discussed

    Phenotypic and karyotypic changes induced in cultured rat hepatic epithelial cells that express the "oval" cell phenotype by exposure to N-methyl-N'-nitro-N-nitrosoguanidine.

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    A diploid population of cultured rat hepatic epithelial cells that expresses the "oval" cell phenotype was exposed briefly and repetitively to N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), and the effect on more than 20 phenotypic properties was evaluated during the neoplastic transformation of the population. MNNG treatments of this hepatic epithelial cell population resulted in a progressively increasing phenotypic alteration and heterogeneity including changes in specific activities of several cellular enzymes and expression of isozymes, synthetic functions, and various in vitro growth properties. Changes in phenotypic expression were clustered episodically and were associated with major karyotypic changes. The development of increasing phenotypic heterogeneity preceding and accompanying tumorigenicity in cultured liver epithelial cells in vitro and the specific phenotypes that occur resemble superficially the pattern of phenotypic changes that occur in hepatocytes during chemical hepatocarcinogenesis in vivo. The results of this study provide the basis for future investigations to further elucidate the mechanistic and linkage relationship between specific pretumorigenic and paratumorigenic phenotypes and tumorigenicity

    Integration of Tmc1/2 into the mechanotransduction complex in zebrafish hair cells is regulated by Transmembrane O-methyltransferase (Tomt).

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    Transmembrane O-methyltransferase (TOMT / LRTOMT) is responsible for non-syndromic deafness DFNB63. However, the specific defects that lead to hearing loss have not been described. Using a zebrafish model of DFNB63, we show that the auditory and vestibular phenotypes are due to a lack of mechanotransduction (MET) in Tomt-deficient hair cells. GFP-tagged Tomt is enriched in the Golgi of hair cells, suggesting that Tomt might regulate the trafficking of other MET components to the hair bundle. We found that Tmc1/2 proteins are specifically excluded from the hair bundle in tomt mutants, whereas other MET complex proteins can still localize to the bundle. Furthermore, mouse TOMT and TMC1 can directly interact in HEK 293 cells, and this interaction is modulated by His183 in TOMT. Thus, we propose a model of MET complex assembly where Tomt and the Tmcs interact within the secretory pathway to traffic Tmc proteins to the hair bundle
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