183 research outputs found
Phase I-II Trial of Foscarnet for Prevention of Cytomegalovirus Infection in Autologous and Allogeneic Marrow Transplant Recipients
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 tomographyâ and positron emission tomographyâscreened patients with stage I lung cancer
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 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
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 âRNase H-likeâ 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 proteinânucleic acid contacts over a region of âŒ14 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 enzymeâsubstrate complex to the enzymeâproduct 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
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
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
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Inflation and Dark Energy from spectroscopy at z > 2
The expansion of the Universe is understood to have accelerated during two
epochs: in its very first moments during a period of Inflation and much more
recently, at z < 1, when Dark Energy is hypothesized to drive cosmic
acceleration. The undiscovered mechanisms behind these two epochs represent
some of the most important open problems in fundamental physics. The large
cosmological volume at 2 < z < 5, together with the ability to efficiently
target high- galaxies with known techniques, enables large gains in the
study of Inflation and Dark Energy. A future spectroscopic survey can test the
Gaussianity of the initial conditions up to a factor of ~50 better than our
current bounds, crossing the crucial theoretical threshold of
of order unity that separates single field and
multi-field models. Simultaneously, it can measure the fraction of Dark Energy
at the percent level up to , thus serving as an unprecedented test of
the standard model and opening up a tremendous discovery space
LSST: from Science Drivers to Reference Design and Anticipated Data Products
(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 deg 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 5
point-source depth in a single visit in will be (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 deg with
, and will be imaged multiple times in six bands, ,
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 deg region about 800 times (summed over all six bands) during the
anticipated 10 years of operations, and yield a coadded map to . 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
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
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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