2,372 research outputs found

    The Life Cycle Stages of \u3cem\u3ePneumocystis murina\u3c/em\u3e Have Opposing Effects on the Immune Response to This Opportunistic Fungal Pathogen

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    The cell wall β-glucans of Pneumocystis cysts have been shown to stimulate immune responses in lung epithelial cells, dendritic cells, and alveolar macrophages. Little is known about how the trophic life forms, which do not have a fungal cell wall, interact with these innate immune cells. Here we report differences in the responses of both neonatal and adult mice to the trophic and cystic life cycle stages of Pneumocystis murina. The adult and neonatal immune responses to infection with Pneumocystis murina trophic forms were less robust than the responses to infection with a physiologically normal mixture of cysts and trophic forms. Cysts promoted the recruitment of nonresident innate immune cells and T and B cells into the lungs. Cysts, but not trophic forms, stimulated increased concentrations of the cytokine gamma interferon (IFN-γ) in the alveolar spaces and an increase in the percentage of CD4+ T cells that produce IFN-γ. In vitro, bone marrow-derived dendritic cells (BMDCs) stimulated with cysts produced the proinflammatory cytokines interleukin 1β (IL-1β) and IL-6. In contrast, trophic forms suppressed antigen presentation to CD4+ T cells, as well as the β-glucan-, lipoteichoic acid (LTA)-, and lipopolysaccharide (LPS)-induced production of interleukin 1β (IL-1β), IL-6, and tumor necrosis factor alpha (TNF-α) by BMDCs. The negative effects of trophic forms were not due to ligation of mannose receptor. Our results indicate that optimal innate and adaptive immune responses to Pneumocystis species are dependent on stimulation with the cyst life cycle stage. Conversely, trophic forms suppress β-glucan-induced proinflammatory responses in vitro, suggesting that the trophic forms dampen cyst-induced inflammation in vivo

    A standardized comparison of peri-operative complications after minimally invasive esophagectomy: Ivor Lewis versus McKeown.

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    BACKGROUND: While our institutional approach to esophageal resection for cancer has traditionally favored a minimally invasive (MI) 3-hole, McKeown esophagectomy (MIE 3-hole) during the last five years several factors has determined a shift in our practice with an increasing number of minimally invasive Ivor Lewis (MIE IL) resections being performed. We compared peri-operative outcomes of the two procedures, hypothesizing that MIE IL would be less morbid in the peri-operative setting compared to MIE 3-hole. METHODS: Our institution\u27s IRB-approved esophageal database was queried to identify all patients who underwent totally MI esophagectomy (MIE IL vs. MIE 3-hole) from June 2011 to May 2016. Patient demographics, preoperative and peri-operative data, as well as post-operative complications were compared between the two groups. Post-operative complications were analyzed using the Clavien-Dindo classification system. RESULTS: There were 110 patients who underwent totally MI esophagectomy (MIE IL n = 49 [45%], MIE 3-hole n = 61 [55%]). The majority of patients were men (n = 91, 83%) with a median age of 62.5 (range 31-83). Preoperative risk stratifiers such as ECOG score, ASA, and Charlson Comorbidity Index were not significantly different between groups. Anastomotic leak rate was 2.0% in the MIE IL group compared to 6.6% in the MIE 3-hole group (p = 0.379). The rate of serious (Clavien-Dindo 3, 4, or 5) post-operative complications was significantly less in the MIE IL group (34.7 vs. 59.0%, p = 0.013). Serious pulmonary complications were not significantly different (16.3 vs. 26.2%, p = 0.251) between the two groups. CONCLUSIONS: In this cohort, totally MIE IL showed significantly less severe peri-operative morbidity than MIE 3-hole, but similar rates of serious pulmonary complications and anastomotic leaks. These findings confirm the safety of minimally invasive Ivor Lewis esophagectomies for esophageal cancer when oncologically and clinically appropriate. Minimally invasive McKeown esophagectomy remains a satisfactory and appropriate option when clinically indicated

    The compact far infrared emission from the young stellar object IRAS 16293-2422

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    High resolution far IR observations at 50 and 100 microns were made of the young stellar object (YSO), IRAS 16293-2422. The observations are part of a systematic high resolution study of nearby YSO's. The purpose is to obtain resolution in the far IR comparable to that at other wavelengths. Until recently, the high resolution that has been available in the far IR has been from either IRAS (angular resolution of approx 4 min) or the KAO using standard FIR photometry (approx 35 sec). With scanning techniques, it is possible to obtain 10 sec resolution on bright sources. Such a resolution is necessary to better determine the physical conditions of the YSO, and to compare with model of star formation. In order to better constrain the models for the source, the YSO was observed at both 50 and 100 microns on several flights in 1988 April from the KAO. Estimates are presented of the size both along the major and minor axis of the disk, as well as estimates of the dust temperature and 100 micron opacity for the YSO

    TEM Cell Testing of Cable Noise Reduction Techniques from 2 MHz to 200 MHz -- Part 2

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    This paper presents empirical results of cable noise reduction techniques as demonstrated in a TEM cell operating with radiated fields from 2 - 200 MHz. It is the second part of a two-paper series. The first paper discussed cable types and shield connections. In this second paper, the effects of load and source resistances and chassis connections are examined. For each topic, well established theories are compared to data from a real-world physical system. Finally, recommendations for minimizing cable susceptibility (and thus cable emissions) are presented. There are numerous papers and textbooks that present theoretical analyses of cable noise reduction techniques. However, empirical data is often targeted to low frequencies (e.g. 100 MHz). Additionally, a comprehensive study showing the relative effects of various noise reduction techniques is needed. These include the use of dedicated return wires, twisted wiring, cable shielding, shield connections, changing load or source impedances, and implementing load- or source-to-chassis isolation. We have created an experimental setup that emulates a real-world electrical system, while still allowing us to independently vary a host of parameters. The goal of the experiment was to determine the relative effectiveness of various noise reduction techniques when the cable is in the presence of radiated emissions from 2 MHz to 200 MHz

    Surgical Apgar Score (SAS) Predicts Perioperative Morbidity and Length of Stay in Patients Undergoing Esophagectomy at a High-Volume Center

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    Background: Esophagectomy is a procedure that carries considerable morbidity. Many studies have evaluated factors to predict patients at risk and improve clinical outcomes. The aim of this study was to determine whether the SAS predicts complications, length of stay, and anastomotic leak for patients undergoing esophagectomy at a high-volume institution.https://jdc.jefferson.edu/surgeryposters/1002/thumbnail.jp

    Molecular dynamics simulation of polymer helix formation using rigid-link methods

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    Molecular dynamics simulations are used to study structure formation in simple model polymer chains that are subject to excluded volume and torsional interactions. The changing conformations exhibited by chains of different lengths under gradual cooling are followed until each reaches a state from which no further change is possible. The interactions are chosen so that the true ground state is a helix, and a high proportion of simulation runs succeed in reaching this state; the fraction that manage to form defect-free helices is a function of both chain length and cooling rate. In order to demonstrate behavior analogous to the formation of protein tertiary structure, additional attractive interactions are introduced into the model, leading to the appearance of aligned, antiparallel helix pairs. The simulations employ a computational approach that deals directly with the internal coordinates in a recursive manner; this representation is able to maintain constant bond lengths and angles without the necessity of treating them as an algebraic constraint problem supplementary to the equations of motion.Comment: 15 pages, 14 figure

    Hubble Tarantula Treasury Project. III. Photometric Catalog and Resulting Constraints on the Progression of Star Formation in the 30 Doradus Region

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    We present and describe the astro-photometric catalog of more than 800,000 sources found in the Hubble Tarantula Treasury Project (HTTP). HTTP is a Hubble Space Telescope (HST) Treasury program designed to image the entire 30 Doradus region down to the sub-solar (~0.5 solar masses) mass regime using the Wide Field Camera 3 (WFC3) and the Advanced Camera for Surveys (ACS). We observed 30 Doradus in the near ultraviolet (F275W, F336W), optical (F555W, F658N, F775W), and near infrared (F110W, F160W) wavelengths. The stellar photometry was measured using point-spread function (PSF) fitting across all the bands simultaneously. The relative astrometric accuracy of the catalog is 0.4 mas. The astro-photometric catalog, results from artificial star experiments and the mosaics for all the filters are available for download. Color-magnitude diagrams are presented showing the spatial distributions and ages of stars within 30 Dor as well as in the surrounding fields. HTTP provides the first rich and statistically significant sample of intermediate and low mass pre-main sequence candidates and allows us to trace how star formation has been developing through the region. The depth and high spatial resolution of our analysis highlight the dual role of stellar feedback in quenching and triggering star formation on the giant HII region scale. Our results are consistent with stellar sub-clustering in a partially filled gaseous nebula that is offset towards our side of the Large Magellanic Cloud.Comment: 20 pages, 22 Figures, 3 Tables, Photometric Catalogs and Mosaiced images will be available for download upon publication, accepted for publication on ApJ

    Observations and Implications of the Star Formation History of the LMC

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    We present derivations of star formation histories based on color-magnitude diagrams of three fields in the LMC from HST/WFPC2 observations. A significant component of stars older than 4 Gyr is required to match the observed color-magnitude diagrams. Models with a dispersion-free age-metallicity relation are unable to reproduce the width of the observed main sequence; models with a range of metallicity at a given age provide a much better fit. Such models allow us to construct complete ``population boxes'' for the LMC based entirely on color-magnitude diagrams; remarkably, these qualitatively reproduce the age-metallicity relation observed in LMC clusters. We discuss some of the uncertainties in deriving star formation histories. We find, independently of the models, that the LMC bar field has a larger relative component of older stars than the outer fields. The main implications suggested by this study are: 1) the star formation history of field stars appears to differ from the age distribution of clusters, 2) there is no obvious evidence for bursty star formation, but our ability to measure bursts shorter in duration than \sim 25% of any given age is limited by the statistics of the observed number of stars, 3) there may be some correlation of the star formation rate with the last close passage of the LMC/SMC/Milky Way, but there is no dramatic effect, and 4) the derived star formation history is probably consistent with observed abundances, based on recent chemical evolution models.Comment: Accepted by AJ, 36 pages including 12 figure
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