138 research outputs found
A Spectrophotometric Method to Determine the Inclination of Class I Objects
A new method which enables us to estimate the inclination of Class I young
stellar objects is proposed. Since Class I objects are not spherically
symmetric, it is likely that the observed feature is sensitive to the
inclination of the system. Thus, we construct a protostar model by carefully
treating two-dimensional (2D) radiative transfer and radiative equilibrium. We
show from the present 2D numerical simulations that the emergent luminosity
L_SED,which is the frequency integration of spectral energy distribution (SED),
depends strongly on the inclination of the system i, whereas the peak flux is
insensitive to i. Based on this result, we introduce a novel indicator f_L,
which is the ratio of L_SED to the peak flux, as a good measure for the
inclination. By using f_L, we can determine the inclination regardless of the
other physical parameters. The inclination would be determined by f_L within
the accuracy of +- 5 degree, if the opening angle of bipolar outflows is
specified by any other procedure. Since this spectrophotometric method is
easier than a geometrical method or a full SED fitting method, this method
could be a powerful tool to investigate the feature of protostars statistically
with observational data which will be provided by future missions, such as
SIRTF, ASTRO-F, and ALMA.Comment: 14 pages, 9 figures, accepted by Ap
Resonant Ultrasound Spectroscopy for Irregularly-Shaped Samples and its Application to Uranium Ditelluride
Resonant ultrasound spectroscopy (RUS) is a powerful technique for measuring
the full elastic tensor of a given material in a single experiment. Previously,
this technique was limited to regularly-shaped samples such as rectangular
parallelepipeds, spheres, and cylinders. We demonstrate a new method for
determining the elastic moduli of irregularly-shaped samples, extending the
applicability of RUS to a much larger set of materials. We apply this new
approach to the recently-discovered unconventional superconductor UTe and
provide its elastic tensor at both 300 and 4 kelvin.Comment: 18 pages, 3 figures, 12 table
Clinical and laboratory predictors for plaque erosion in patients with acute coronary syndromes
Background-—Plaque erosion is responsible for 25% to 40% of patients with acute coronary syndromes (ACS). Recent studies
suggest that anti-thrombotic therapy without stenting may be an option for this subset of patients. Currently, however, an invasive
procedure is required to make a diagnosis of plaque erosion. The aim of this study was to identify clinical or laboratory predictors
of plaque erosion in patients with ACS to enable a diagnosis of erosion without additional invasive procedures.
Methods and Results-—Patients with ACS who underwent optical coherence tomography imaging were selected from 11
institutions in 6 countries. The patients were classified into plaque rupture, plaque erosion, or calcified plaque, and predictors were
identified using multivariable logistic modeling. Among 1241 patients with ACS, 477 (38.4%) patients were found to have plaque
erosion. Plaque erosion was more frequent in non–ST-segment elevation-ACS than in ST-segment–elevation myocardial infarction
(47.9% versus 29.8%, P=0.0002). Multivariable logistic regression models showed 5 independent parameters associated with
plaque erosion: age 15.0 g/dL, and normal renal function. When
all 5 parameters are present in a patient with non–ST-segment elevation-ACS, the probability of plaque erosion increased to 73.1%.
Conclusions-—Clinical and laboratory parameters associatedwith plaque erosion are explored in this retrospective registry study. These
parametersmay be useful to identify the subset ofACS patients with plaque erosion and guide themto conservativemanagement without
invasive procedures. The results of this exploratory analysis need to be confirmed in large scale prospective clinical studiesDr. Jang has received an educational grant from Abbott
Vascular and Medicure. Dr. Adriaenssens has received grants
and consulting fees from Abbott Vascula
Human Cryptochrome-1 Confers Light Independent Biological Activity in Transgenic Drosophila Correlated with Flavin Radical Stability
Cryptochromes are conserved flavoprotein receptors found throughout the biological kingdom with diversified roles in plant development and entrainment of the circadian clock in animals. Light perception is proposed to occur through flavin radical formation that correlates with biological activity in vivo in both plants and Drosophila. By contrast, mammalian (Type II) cryptochromes regulate the circadian clock independently of light, raising the fundamental question of whether mammalian cryptochromes have evolved entirely distinct signaling mechanisms. Here we show by developmental and transcriptome analysis that Homo sapiens cryptochrome - 1 (HsCRY1) confers biological activity in transgenic expressing Drosophila in darkness, that can in some cases be further stimulated by light. In contrast to all other cryptochromes, purified recombinant HsCRY1 protein was stably isolated in the anionic radical flavin state, containing only a small proportion of oxidized flavin which could be reduced by illumination. We conclude that animal Type I and Type II cryptochromes may both have signaling mechanisms involving formation of a flavin radical signaling state, and that light independent activity of Type II cryptochromes is a consequence of dark accumulation of this redox form in vivo rather than of a fundamental difference in signaling mechanism
Antifibrotic Effects of the Dual CCR2/CCR5 Antagonist Cenicriviroc in Animal Models of Liver and Kidney Fibrosis
Background & Aims
Interactions between C-C chemokine receptor types 2 (CCR2) and 5 (CCR5) and their ligands, including CCL2 and CCL5, mediate fibrogenesis by promoting monocyte/macrophage recruitment and tissue infiltration, as well as hepatic stellate cell activation. Cenicriviroc (CVC) is an oral, dual CCR2/CCR5 antagonist with nanomolar potency against both receptors. CVC’s anti-inflammatory and antifibrotic effects were evaluated in a range of preclinical models of inflammation and fibrosis.
Methods
Monocyte/macrophage recruitment was assessed in vivo in a mouse model of thioglycollate-induced peritonitis. CCL2-induced chemotaxis was evaluated ex vivo on mouse monocytes. CVC’s antifibrotic effects were evaluated in a thioacetamide-induced rat model of liver fibrosis and mouse models of diet-induced non-alcoholic steatohepatitis (NASH) and renal fibrosis. Study assessments included body and liver/kidney weight, liver function test, liver/kidney morphology and collagen deposition, fibrogenic gene and protein expression, and pharmacokinetic analyses.
Results
CVC significantly reduced monocyte/macrophage recruitment in vivo at doses ≥20 mg/kg/day (p < 0.05). At these doses, CVC showed antifibrotic effects, with significant reductions in collagen deposition (p < 0.05), and collagen type 1 protein and mRNA expression across the three animal models of fibrosis. In the NASH model, CVC significantly reduced the non-alcoholic fatty liver disease activity score (p < 0.05 vs. controls). CVC treatment had no notable effect on body or liver/kidney weight.
Conclusions
CVC displayed potent anti-inflammatory and antifibrotic activity in a range of animal fibrosis models, supporting human testing for fibrotic diseases. Further experimental studies are needed to clarify the underlying mechanisms of CVC’s antifibrotic effects. A Phase 2b study in adults with NASH and liver fibrosis is fully enrolled (CENTAUR Study 652-2-203; NCT02217475)
Sickness behaviour pushed too far – the basis of the syndrome seen in severe protozoal, bacterial and viral diseases and post-trauma
Certain distinctive components of the severe systemic inflammatory syndrome are now well-recognized to be common to malaria, sepsis, viral infections, and post-trauma illness. While their connection with cytokines has been appreciated for some time, the constellation of changes that comprise the syndrome has simply been accepted as an empirical observation, with no theory to explain why they should coexist. New data on the effects of the main pro-inflammatory cytokines on the genetic control of sickness behaviour can be extended to provide a rationale for why this syndrome contains many of its accustomed components, such as reversible encephalopathy, gene silencing, dyserythropoiesis, seizures, coagulopathy, hypoalbuminaemia and hypertriglyceridaemia. It is thus proposed that the pattern of pathology that comprises much of the systemic inflammatory syndrome occurs when one of the usually advantageous roles of pro-inflammatory cytokines – generating sickness behaviour by moderately repressing genes (Dbp, Tef, Hlf, Per1, Per2 and Per3, and the nuclear receptor Rev-erbα) that control circadian rhythm – becomes excessive. Although reversible encephalopathy and gene silencing are severe events with potentially fatal consequences, they can be viewed as having survival advantages through lowering energy demand. In contrast, dyserythropoiesis, seizures, coagulopathy, hypoalbuminaemia and hypertriglyceridaemia may best be viewed as unfortunate consequences of extreme repression of these same genetic controls when the pro-inflammatory cytokines that cause sickness behaviour are produced excessively. As well as casting a new light on the previously unrationalized coexistence of these aspects of systemic inflammatory diseases, this concept is consistent with the case for a primary role for inflammatory cytokines in their pathogenesis across this range of diseases
Phosphoregulation of tropomyosin is crucial for actin cable turnover and division site placement
Tropomyosin is a coiled-coil actin binding protein key to the stability of actin filaments. Whereas, in muscle cells, tropomyosin is subject to calcium regulation, its regulation in non-muscle cells is not understood. Here, we provide evidence that the fission yeast tropomyosin, Cdc8, is regulated by phosphorylation of a serine residue. Failure of phosphorylation leads to an increased number and stability of actin cables and causes misplacement of the division site in certain genetic backgrounds. Phosphorylation of Cdc8 weakens its interaction with actin filaments. Furthermore, we show through in vitro reconstitution that phosphorylation-mediated release of Cdc8 from actin filaments facilitates access of the actin severing protein Adf1 and subsequent filament disassembly. These studies establish that phosphorylation may be a key mode of regulation of non-muscle tropomyosins, which in fission yeast controls actin filament stability and division site placement
The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2
Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age 6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score 652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701
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