SARS-CoV replication and pathogenesis in an in vitro model of the human conducting airway epithelium

SARS coronavirus (SARS-CoV) emerged in 2002 as an important cause of severe lower respiratory tract infection in humans and in vitro models of the lung are needed to elucidate cellular targets and the consequences of viral infection. The severe and sudden onset of symptoms, resulting in an atypical pneumonia with dry cough and persistent high fever in cases of severe acute respiratory virus brought to light the importance of coronaviruses as potentially lethal human pathogens and the identification of several zoonotic reservoirs has made the reemergence of new strains and future epidemics all the more possible. In this chapter, we describe the pathology of SARS-CoV infection in humans and explore the use of two models of the human conducting airway to develop a better understanding of the replication and pathogenesis of SARS-CoV in relevant in vitro systems. The first culture model is a human bronchial epithelial cell line Calu3 that can be inoculated by viruses either as a non-polarized monolayer of cells or polarized cells with tight junctions and microvilli. The second model system, derived from primary cells isolated from human airway epithelium and grown on Transwells, form a pseudostratified mucociliary epithelium that recapitulates the morphological and physiological features of the human conducting airway in vivo. Experimental results using these lung epithelial cell models demonstrate that in contrast to the pathology reported in late stage cases SARS-CoV replicates to high titers in epithelial cells of the conducting airway. The SARS-CoV receptor, human angiotensin 1 converting enzyme 2 (hACE2), was detected exclusively on the apical surface of cells in polarized Calu3 cells and human airway epithelial cultures (HAE), indicating that hACE2 was accessible by SARS-CoV after airway lumenal delivery. Furthermore, in HAE, hACE2 was exclusively localized to ciliated airway epithelial cells. In support of the hACE2 localization data, the most productive route of inoculation and progeny virion egress in both polarized Calu3 and ciliated cells of HAE was the apical surface suggesting mechanisms to release large quantities of virus into the lumen of the human lung. Preincubation of the apical surface of cultures with antisera directed against hACE2 reduced viral titers by 2 logs while antisera against DC-SIGN/DC-SIGNR did not reduce viral replication levels suggesting that hACE2 is the primary receptor for entry of SARS-CoV into the ciliated cells of HAE cultures. To assess infectivity in ciliated airway cultures derived from susceptible animal species we generated a recombinant SARS-CoV by deletion of open reading frame 7a/7b (ORF 7a/b) and insertion of the green fluorescent protein (GFP) resulting in SARS-CoV GFP. SARS-CoV GFP replicated to similar titers as wild type viruses in Vero E6, MA104, and CaCo2 cells. In addition, SARS-CoV replication in airway epithelial cultures generated from Golden Syrian hamster tracheas reached similar titers to the human cultures by 72 hours post infection. Efficient SARS-CoV infection of ciliated cell-types in HAE provides a useful in vitro model of human lung origin to study characteristics of SARS-CoV replication and pathogenesis

Effect of thoracic venting on arterial pressure, and flow during external cardiopulmonary resuscitation in animals

To test the hypothesis that fluctuations in global intrathoracic pressure are the dominant cause of blood flow during external cardiopulmonary resuscitation (CPR) the authors studied the effects of open pneumothorax on experimental CPR in 7 domestic pigs and 12 mongrel dogs. Similar studies were conducted independently at three laboratories and are reported jointly. All studies were conducted during electrically induced ventricular fibrillation and with standard CPR technique, including ventral-dorsal chest compression at 60/min, 0.5 sec compression duration, 1:5ventilation:compression ratio. During alternate periods of CPR, intrathoracic pressure was vented through bilateral chest tubes, placed to create open pneumothorax and partial collapse of the lungs. During this maneuver, global intrathoracic pressure fluctuations were greatly attenuated, but direct but direct cardiac compression and adequate ventilation continued. In the three laboratories, systolic/diastolic arterial pressures during CPR with thoracic venting (± SE) averaged 68 ± 4.2/28 ± 3.3, 60 ± 10/18 ± 4.5, and 66 ± 6.3/23 ± 1.5 mm Hg. These values are compared to 68 ± 4.4/27 ± 3.0, 67 ± 12/17 ± 6.1, and 56± 6.2/22 ± 1.9 mm Hg with the thorax intact. Carotid artery mean flow, measured with an in-line flowmeter, was 13.0 ± 2.2 ml/min vented vs. 13.4 ± 2.6 intact in 7 pigs; 11.4 ± 3.8 ml/min vented vs. 11.2 ± 3.7 intact in 5 dogs. Cardiac output, determined by indicator dilution, was 25 ± 4.3 ml/min/kg vented vs. 20 ± 4.3 intact in 7 dogs. Thoracic venting did not decrease blood pressures and flows during CPR, as would be predicted from the hypothesis that generalized intrathoracic pressure fluctuations are the dominant hemodynamic mechanism. The results are consistent with the classical notion that CPR works by compression of the heart between the sternum and the spine. This mechanism should not be discounted in future attempts to improve CPR

Theory of Cylindrical Tubules and Helical Ribbons of Chiral Lipid Membranes

We present a general theory for the equilibrium structure of cylindrical tubules and helical ribbons of chiral lipid membranes. This theory is based on a continuum elastic free energy that permits variations in the direction of molecular tilt and in the curvature of the membrane. The theory shows that the formation of tubules and helical ribbons is driven by the chirality of the membrane. Tubules have a first-order transition from a uniform state to a helically modulated state, with periodic stripes in the tilt direction and ripples in the curvature. Helical ribbons can be stable structures, or they can be unstable intermediate states in the formation of tubules.Comment: 43 pages, including 12 postscript figures, uses REVTeX 3.0 and epsf.st

Developing GIS-based eastern equine encephalitis vector-host models in Tuskegee, Alabama

<p>Abstract</p> <p>Background</p> <p>A site near Tuskegee, Alabama was examined for vector-host activities of eastern equine encephalomyelitis virus (EEEV). Land cover maps of the study site were created in ArcInfo 9.2^®from QuickBird data encompassing visible and near-infrared (NIR) band information (0.45 to 0.72 μm) acquired July 15, 2008. Georeferenced mosquito and bird sampling sites, and their associated land cover attributes from the study site, were overlaid onto the satellite data. SAS 9.1.4^®was used to explore univariate statistics and to generate regression models using the field and remote-sampled mosquito and bird data. Regression models indicated that <it>Culex erracticus </it>and Northern Cardinals were the most abundant mosquito and bird species, respectively. Spatial linear prediction models were then generated in Geostatistical Analyst Extension of ArcGIS 9.2^®. Additionally, a model of the study site was generated, based on a Digital Elevation Model (DEM), using ArcScene extension of ArcGIS 9.2^®.</p> <p>Results</p> <p>For total mosquito count data, a first-order trend ordinary kriging process was fitted to the semivariogram at a partial sill of 5.041 km, nugget of 6.325 km, lag size of 7.076 km, and range of 31.43 km, using 12 lags. For total adult <it>Cx. erracticus </it>count, a first-order trend ordinary kriging process was fitted to the semivariogram at a partial sill of 5.764 km, nugget of 6.114 km, lag size of 7.472 km, and range of 32.62 km, using 12 lags. For the total bird count data, a first-order trend ordinary kriging process was fitted to the semivariogram at a partial sill of 4.998 km, nugget of 5.413 km, lag size of 7.549 km and range of 35.27 km, using 12 lags. For the Northern Cardinal count data, a first-order trend ordinary kriging process was fitted to the semivariogram at a partial sill of 6.387 km, nugget of 5.935 km, lag size of 8.549 km and a range of 41.38 km, using 12 lags. Results of the DEM analyses indicated a statistically significant inverse linear relationship between total sampled mosquito data and elevation (R²= -.4262; p < .0001), with a standard deviation (SD) of 10.46, and total sampled bird data and elevation (R²= -.5111; p < .0001), with a SD of 22.97. DEM statistics also indicated a significant inverse linear relationship between total sampled <it>Cx. erracticus </it>data and elevation (R²= -.4711; p < .0001), with a SD of 11.16, and the total sampled Northern Cardinal data and elevation (R²= -.5831; p < .0001), SD of 11.42.</p> <p>Conclusion</p> <p>These data demonstrate that GIS/remote sensing models and spatial statistics can capture space-varying functional relationships between field-sampled mosquito and bird parameters for determining risk for EEEV transmission.</p

Gun rites: hegemonic masculinity and neoliberal ideology in rural Kansas

Drawing upon empirical data from a qualitative research project in Southeast Kansas, this paper employs feminist and decolonial theories to analyse the interlocking relationality of hegemonic masculinity, neoliberal ideology, social conservatism, rurality, and gun culture. The first goal is to shed light on the subordinating and marginalizing tendencies that arise as a result of gendered conceptions of gun use. The second aim is to illustrate how gun culture is normalized, and often valorized, through individualistic narratives of self-reliance, security, protection, and defence. The third objective is to interrogate the ways in which particular material practices and gendered discourses regarding gun use are reinforced by settler colonialism, whiteness, heteronormativity, enabledness, and nationalism. Finally, the paper critically examines the social hierarchies that are reaffirmed as a result of culturally embedded patriarchal, white supremacist, and neoliberal ideologies, and how rurality mediates the masculinist subjectivities that are produced in such spaces

An IL-27-Driven Transcriptional Network Identifies Regulators of IL-10 Expression across T Helper Cell Subsets.

Interleukin-27 (IL-27) is an immunoregulatory cytokine that suppresses inflammation through multiple mechanisms, including induction of IL-10, but the transcriptional network mediating its diverse functions remains unclear. Combining temporal RNA profiling with computational algorithms, we predict 79 transcription factors induced by IL-27 in T cells. We validate 11 known and discover 5 positive (Cebpb, Fosl2, Tbx21, Hlx, and Atf3) and 2 negative (Irf9 and Irf8) Il10 regulators, generating an experimentally refined regulatory network for Il10. We report two central regulators, Prdm1 and Maf, that cooperatively drive the expression of signature genes induced by IL-27 in type 1 regulatory T cells, mediate IL-10 expression in all T helper cells, and determine the regulatory phenotype of colonic Foxp3 &lt;sup&gt;+&lt;/sup&gt; regulatory T cells. Prdm1/Maf double-knockout mice develop spontaneous colitis, phenocopying ll10-deficient mice. Our work provides insights into IL-27-driven transcriptional networks and identifies two shared Il10 regulators that orchestrate immunoregulatory programs across T helper cell subsets

Precision Top-Quark Mass Measurements at CDF

We present a precision measurement of the top-quark mass using the full sample of Tevatron $\sqrt{s}=1.96$ TeV proton-antiproton collisions collected by the CDF II detector, corresponding to an integrated luminosity of 8.7 $fb^{-1}$. Using a sample of $t\bar{t}$ candidate events decaying into the lepton+jets channel, we obtain distributions of the top-quark masses and the invariant mass of two jets from the $W$ boson decays from data. We then compare these distributions to templates derived from signal and background samples to extract the top-quark mass and the energy scale of the calorimeter jets with {\it in situ} calibration. The likelihood fit of the templates from signal and background events to the data yields the single most-precise measurement of the top-quark mass, \mtop = 172.85 \pm$0.71 (stat)$\pm$0.85 (syst) GeV/c^{2}.$Comment: submitted to Phys. Rev. Let