183 research outputs found

    Phase I-II Trial of Foscarnet for Prevention of Cytomegalovirus Infection in Autologous and Allogeneic Marrow Transplant Recipients

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    The safety and efficacy of foscarnet for prevention of cytomegalovirus (CMV) infection was evaluated in 19 CMV-seropositive bone marrow transplant (BMT) recipients. All patients received intermittent intravenous (iv) foscarnet: 40 mg/kg every 8 h from 7 days before to day 30 after BMT, then 60 mg/kg once a day until day 75. The main toxicity was transient renal dysfunction, with a >50 ”mol/L increase in serum creatinine above baseline in 5 of the 7 autograft recipients and in 6 of the 12 allograft recipients. Only 4 allograft recipients developed CMV infection during foscarnet prophylaxis, and no patient showed evidenceofCMV disease. Because 3 allograft recipients receiving concomitant iv amphotericin B showed rapid impairment of renal function, foscarnet prophylaxis should not be given to allograft recipients requiring amphotericin B; otherwise, foscarnet prophylaxis at this dose appears safe after BM

    Cost-effectiveness of routine mediastinoscopy in computed tomography– and positron emission tomography–screened patients with stage I lung cancer

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    ObjectiveAccurate preoperative staging is essential for the optimal management of patients with lung cancer. An important goal of preoperative staging is to identify mediastinal lymph node metastasis. Computed tomography and positron emission tomography may identify mediastinal lymph node metastasis with sufficient sensitivity to allow omission of mediastinoscopy. This study utilizes our experience with patients with clinical stage I lung cancer to perform a decision analysis addressing whether mediastinoscopy should be performed in clinical stage I lung cancer patients staged by computed tomography and positron emission tomography.MethodsWe retrospectively reviewed our thoracic surgery database for cases between May 1999 and May 2004. Patients deemed clinical stage I by computed tomography and positron emission tomography were chosen for further study. Individual computed tomography, positron emission tomography, and operative and pathology reports were reviewed. The postresection pathologic staging and long-term survival were recorded. A decision model was created using TreeAgePro software and our observed data for the prevalence of mediastinal lymph node metastases and for the rate of benign nodules. Data reported in the literature were also utilized to complete the decision analysis model. A sensitivity analysis of key variables was performed.ResultsA total of 248 patients with clinical stage I lung tumors were identified. One hundred seventy-eight patients (72%) underwent mediastinoscopy before resection, and 5/178 (3%) showed N2 disease. An additional 9 patients were found to have N2 metastasis in the final resected specimen, resulting in a total of 14/248 patients (5.6%) with occult mediastinal lymph node metastases. Benign nodules were found in 19/248 (8%) of patients. Decision analysis determined that mediastinoscopy added 0.008 years of life expectancy at a cost of 250,989perlife−yeargained.TheoutcomewassensitivetotheprevalenceofN2diseaseinthepopulationandthebenefitofinductionversusadjuvanttherapyforN2lungcancer.IftheprevalenceofN2diseaseexceeds10250,989 per life-year gained. The outcome was sensitive to the prevalence of N2 disease in the population and the benefit of induction versus adjuvant therapy for N2 lung cancer. If the prevalence of N2 disease exceeds 10%, the sensitivity analysis predicts that mediastinoscopy would lengthen life at a cost of less than 100,000 per life-year gained.ConclusionPatients with clinical stage I lung cancer staged by computed tomography and positron emission tomography benefit little from mediastinoscopy. The survival advantage it confers is very small and is dependent on the prevalence of N2 metastasis and the unproven superiority of induction therapy over adjuvant therapy

    Characterization of the C-Terminal Nuclease Domain of Herpes Simplex Virus pUL15 as a Target of Nucleotidyltransferase Inhibitors

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    The natural product α-hydroxytropolones manicol and ÎČ-thujaplicinol inhibit replication of herpes simplex viruses 1 and 2 (HSV-1 and HSV-2, respectively) at nontoxic concentrations. Because these were originally developed as divalent metal-sequestering inhibitors of the ribonuclease H activity of HIV-1 reverse transcriptase, α-hydroxytropolones likely target related HSV proteins of the nucleotidyltransferase (NTase) superfamily, which share an “RNase H-like” fold. One potential candidate is pUL15, a component of the viral terminase molecular motor complex, whose C-terminal nuclease domain, pUL15C, has recently been crystallized. Crystallography also provided a working model for DNA occupancy of the nuclease active site, suggesting potential protein–nucleic acid contacts over a region of ∌14 bp. In this work, we extend crystallographic analysis by examining pUL15C-mediated hydrolysis of short, closely related DNA duplexes. In addition to defining a minimal substrate length, this strategy facilitated construction of a dual-probe fluorescence assay for rapid kinetic analysis of wild-type and mutant nucleases. On the basis of its proposed role in binding the phosphate backbone, studies with pUL15C variant Lys700Ala showed that this mutation affected neither binding of duplex DNA nor binding of small molecule to the active site but caused a 17-fold reduction in the turnover rate (kcat), possibly by slowing conversion of the enzyme–substrate complex to the enzyme–product complex and/or inhibiting dissociation from the hydrolysis product. Finally, with a view of pUL15-associated nuclease activity as an antiviral target, the dual-probe fluorescence assay, in combination with differential scanning fluorimetry, was used to demonstrate inhibition by several classes of small molecules that target divalent metal at the active site

    Effects of Heterogeneous and Clustered Contact Patterns on Infectious Disease Dynamics

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    The spread of infectious diseases fundamentally depends on the pattern of contacts between individuals. Although studies of contact networks have shown that heterogeneity in the number of contacts and the duration of contacts can have far-reaching epidemiological consequences, models often assume that contacts are chosen at random and thereby ignore the sociological, temporal and/or spatial clustering of contacts. Here we investigate the simultaneous effects of heterogeneous and clustered contact patterns on epidemic dynamics. To model population structure, we generalize the configuration model which has a tunable degree distribution (number of contacts per node) and level of clustering (number of three cliques). To model epidemic dynamics for this class of random graph, we derive a tractable, low-dimensional system of ordinary differential equations that accounts for the effects of network structure on the course of the epidemic. We find that the interaction between clustering and the degree distribution is complex. Clustering always slows an epidemic, but simultaneously increasing clustering and the variance of the degree distribution can increase final epidemic size. We also show that bond percolation-based approximations can be highly biased if one incorrectly assumes that infectious periods are homogeneous, and the magnitude of this bias increases with the amount of clustering in the network. We apply this approach to model the high clustering of contacts within households, using contact parameters estimated from survey data of social interactions, and we identify conditions under which network models that do not account for household structure will be biased

    CMB-S4 Science Book, First Edition

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    This book lays out the scientific goals to be addressed by the next-generation ground-based cosmic microwave background experiment, CMB-S4, envisioned to consist of dedicated telescopes at the South Pole, the high Chilean Atacama plateau and possibly a northern hemisphere site, all equipped with new superconducting cameras. CMB-S4 will dramatically advance cosmological studies by crossing critical thresholds in the search for the B-mode polarization signature of primordial gravitational waves, in the determination of the number and masses of the neutrinos, in the search for evidence of new light relics, in constraining the nature of dark energy, and in testing general relativity on large scales

    LSST: from Science Drivers to Reference Design and Anticipated Data Products

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    (Abridged) We describe here the most ambitious survey currently planned in the optical, the Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. LSST will be a wide-field ground-based system sited at Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg2^2 field of view, and a 3.2 Gigapixel camera. The standard observing sequence will consist of pairs of 15-second exposures in a given field, with two such visits in each pointing in a given night. With these repeats, the LSST system is capable of imaging about 10,000 square degrees of sky in a single filter in three nights. The typical 5σ\sigma point-source depth in a single visit in rr will be ∌24.5\sim 24.5 (AB). The project is in the construction phase and will begin regular survey operations by 2022. The survey area will be contained within 30,000 deg2^2 with ÎŽ<+34.5∘\delta<+34.5^\circ, and will be imaged multiple times in six bands, ugrizyugrizy, covering the wavelength range 320--1050 nm. About 90\% of the observing time will be devoted to a deep-wide-fast survey mode which will uniformly observe a 18,000 deg2^2 region about 800 times (summed over all six bands) during the anticipated 10 years of operations, and yield a coadded map to r∌27.5r\sim27.5. The remaining 10\% of the observing time will be allocated to projects such as a Very Deep and Fast time domain survey. The goal is to make LSST data products, including a relational database of about 32 trillion observations of 40 billion objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures available from https://www.lsst.org/overvie

    CMB-HD: an Ultra-Deep, High-Resolution Millimeter-Wave Survey over Half the Sky

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    A millimeter-wave survey over half the sky, that spans frequencies in the range of 30 to 350 gigahertz, and that is both an order of magnitude deeper and of higher-resolution than currently funded surveys would yield an enormous gain in understanding of both fundamental physics and astrophysics. By providing such a deep, high-resolution millimeter-wave survey (about 0.5 microK-arcminutes noise and 15 arcseconds resolution at 150 gigahertz), CMB-HD (Cosmic Microwave Background - Henry Draper catalog entry) will enable major advances. It will allow 1) the use of gravitational lensing of the primordial microwave background to map the distribution of matter on small scales (k approximately equal to 10 h per megaparsec), which probes dark matter particle properties. It will also allow 2) measurements of the thermal and kinetic Sunyaev-Zeldovich effects on small scales to map the gas density and gas pressure profiles of halos over a wide field, which probes galaxy evolution and cluster astrophysics. In addition, CMB-HD would allow us to cross critical thresholds in fundamental physics: 3) ruling out or detecting any new, light (less than 0.1 electronvolts), thermal particles, which could potentially be the dark matter, and 4) testing a wide class of multi-field models that could explain an epoch of inflation in the early Universe. Such a survey would also 5) monitor the transient sky by mapping the full observing region every few days, which opens a new window on gamma-ray bursts, novae, fast radio bursts, and variable active galactic nuclei. Moreover, CMB-HD would 6) provide a census of planets, dwarf planets, and asteroids in the outer Solar System, and 7) enable the detection of exo-Oort clouds around other solar systems, shedding light on planet formation. The combination of CMB-HD with contemporary ground and space-based experiments will also provide powerful synergies. CMB-HD will deliver this survey in 5 years of observing 20,000 square degrees, using two new 30-meter-class off-axis cross-Dragone telescopes to be located at Cerro Toco in the Atacama Desert. The telescopes will field about 2.4 million detectors (600,000 pixels) in total. The CMB-HD survey will be made publicly available, with usability and accessibility a priority

    Report of the Topical Group on Cosmic Probes of Dark Matter for Snowmass 2021

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    Cosmological and astrophysical observations currently provide the only robust, positive evidence for dark matter. Cosmic probes of dark matter, which seek to determine the fundamental properties of dark matter through observations of the cosmos, have emerged as a promising means to reveal the nature of dark matter. This report summarizes the current status and future potential of cosmic probes to inform our understanding of the fundamental nature of dark matter in the coming decade.Comment: Report of the CF3 Topical Group for Snowmass 2021; 35 pages, 10 figures, many references. V3 updates Fig 3-2 and the author lis
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