271 research outputs found

    Parent-of-origin-specific allelic associations among 106 genomic loci for age at menarche.

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    Age at menarche is a marker of timing of puberty in females. It varies widely between individuals, is a heritable trait and is associated with risks for obesity, type 2 diabetes, cardiovascular disease, breast cancer and all-cause mortality. Studies of rare human disorders of puberty and animal models point to a complex hypothalamic-pituitary-hormonal regulation, but the mechanisms that determine pubertal timing and underlie its links to disease risk remain unclear. Here, using genome-wide and custom-genotyping arrays in up to 182,416 women of European descent from 57 studies, we found robust evidence (P < 5 × 10(-8)) for 123 signals at 106 genomic loci associated with age at menarche. Many loci were associated with other pubertal traits in both sexes, and there was substantial overlap with genes implicated in body mass index and various diseases, including rare disorders of puberty. Menarche signals were enriched in imprinted regions, with three loci (DLK1-WDR25, MKRN3-MAGEL2 and KCNK9) demonstrating parent-of-origin-specific associations concordant with known parental expression patterns. Pathway analyses implicated nuclear hormone receptors, particularly retinoic acid and γ-aminobutyric acid-B2 receptor signalling, among novel mechanisms that regulate pubertal timing in humans. Our findings suggest a genetic architecture involving at least hundreds of common variants in the coordinated timing of the pubertal transition

    The Pioneer Anomaly

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    Radio-metric Doppler tracking data received from the Pioneer 10 and 11 spacecraft from heliocentric distances of 20-70 AU has consistently indicated the presence of a small, anomalous, blue-shifted frequency drift uniformly changing with a rate of ~6 x 10^{-9} Hz/s. Ultimately, the drift was interpreted as a constant sunward deceleration of each particular spacecraft at the level of a_P = (8.74 +/- 1.33) x 10^{-10} m/s^2. This apparent violation of the Newton's gravitational inverse-square law has become known as the Pioneer anomaly; the nature of this anomaly remains unexplained. In this review, we summarize the current knowledge of the physical properties of the anomaly and the conditions that led to its detection and characterization. We review various mechanisms proposed to explain the anomaly and discuss the current state of efforts to determine its nature. A comprehensive new investigation of the anomalous behavior of the two Pioneers has begun recently. The new efforts rely on the much-extended set of radio-metric Doppler data for both spacecraft in conjunction with the newly available complete record of their telemetry files and a large archive of original project documentation. As the new study is yet to report its findings, this review provides the necessary background for the new results to appear in the near future. In particular, we provide a significant amount of information on the design, operations and behavior of the two Pioneers during their entire missions, including descriptions of various data formats and techniques used for their navigation and radio-science data analysis. As most of this information was recovered relatively recently, it was not used in the previous studies of the Pioneer anomaly, but it is critical for the new investigation.Comment: 165 pages, 40 figures, 16 tables; accepted for publication in Living Reviews in Relativit

    Changes of bone turnover markers and serum PTH after night or morning administration of zoledronic acid in breast cancer patients with bone metastases

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    Persistent circadian rhythm of bone turnover in bone metastatic breast cancer suggests greater skeletal retention of bisphosphonates if administered in the night. We assessed differential effects of night vs morning administration of zoledronic acid (ZA) on bone turnover. Forty-four breast cancer patients with bone metastases were randomised to receive intravenous ZA (4 mg) at 1100 or 2300 hours every 28 days for four times. Urinary concentration N-telopeptide of type-I collagen (NTX) and deoxypyridinolines, and serum C-telopeptide of type-I collagen (CTX), bone alkaline phosphatase (ALP), osteocalcin and Parathyroid hormone (PTH) was measured in the morning at baseline and after 4, 7, 14, 28, 56 and 84 days. Urinary ZA concentration was also measured. Zoledronic acid caused significant decreases of NTX and CTX (P<0.001), without any difference in percent changes between night and morning arms. Bone ALP and osteocalcin were also significantly affected by ZA (P=0.001), without any difference between arms. Parathyroid hormone significantly increased in both the arms; PTH increase was lower in the night arm (P=0.001). From the second administration onwards, urinary ZA level was significantly higher in the night arm (P<0.01). Administration of ZA at two opposite phases of the circadian cycle causes similar changes of bone-turnover marker levels, but has differential effects on the level of serum PTH

    Hepatocyte Growth Factor (HGF) Inhibits Collagen I and IV Synthesis in Hepatic Stellate Cells by miRNA-29 Induction

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    BACKGROUND: In chronic liver disease, hepatic stellate cells (HSC) transdifferentiate into myofibroblasts, promoting extracellular matrix (ECM) synthesis and deposition. Stimulation of HSC by transforming growth factor-β (TGF-β) is a crucial event in liver fibrogenesis due to its impact on myofibroblastic transition and ECM induction. In contrast, hepatocyte growth factor (HGF), exerts antifibrotic activities. Recently, miR-29 has been reported to be involved in ECM synthesis. We therefore studied the influence of HGF and TGF-β on the miR-29 collagen axis in HSC. METHODOLOGY: HSC, isolated from rats, were characterized for HGF and Met receptor expression by Real-Time PCR and Western blotting during culture induced myofibroblastic transition. Then, the levels of TGF-β, HGF, collagen-I and -IV mRNA, in addition to miR-29a and miR-29b were determined after HGF and TGF-β stimulation of HSC or after experimental fibrosis induced by bile-duct obstruction in rats. The interaction of miR-29 with 3'-untranslated mRNA regions (UTR) was analyzed by reporter assays. The repressive effect of miR-29 on collagen synthesis was studied in HSC treated with miR-29-mimicks by Real-Time PCR and immunoblotting. PRINCIPAL FINDINGS: The 3'-UTR of the collagen-1 and -4 subtypes were identified to bind miR-29. Hence, miR-29a/b overexpression in HSC resulted in a marked reduction of collagen-I and -IV synthesis. Conversely, a decrease in miR-29 levels is observed during collagen accumulation upon experimental fibrosis, in vivo, and after TGF-β stimulation of HSC, in vitro. Finally, we show that during myofibroblastic transition and TGF-β exposure the HGF-receptor, Met, is upregulated in HSC. Thus, whereas TGF-β stimulation leads to a reduction in miR-29 expression and de-repression of collagen synthesis, stimulation with HGF was definitely associated with highly elevated miR-29 levels and markedly repressed collagen-I and -IV synthesis. CONCLUSIONS: Upregulation of miRNA-29 by HGF and downregulation by TGF-β take part in the anti- or profibrogenic response of HSC, respectively

    24-Hour ambulatory blood pressure control with triple-therapy amlodipine, valsartan and hydrochlorothiazide in patients with moderate to severe hypertension

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    To determine the effectiveness and safety of once-daily combination therapy with amlodipine, valsartan and hydrochlorothiazide for reducing ambulatory blood pressure (ABP) in patients with moderate to severe hypertension, a multicenter, double-blind study was performed (N=2271) that included ABP monitoring in a 283-patient subset. After a single-blind, placebo run-in period, patients were randomized to receive amlodipine/valsartan/hydrochlorothiazide (10/320/25 mg), valsartan/hydrochlorothiazide (320/25 mg), amlodipine/valsartan (10/320 mg) or amlodipine/hydrochlorothiazide (10/25 mg) each morning for 8 weeks. Efficacy assessments included change from baseline in 24-h, daytime and night time mean ambulatory systolic BP (SBP) and diastolic BP (DBP). Statistically significant and clinically relevant reductions from baseline in all these parameters occurred in all treatment groups (P<0.0001, all comparisons versus baseline). At week 8, least squares mean reductions from baseline in 24-h, daytime and night time mean ambulatory SBP/DBP were 30.3/19.7, 31.2/20.5 and 28.0/17.8 mm Hg, respectively, with amlodipine/valsartan/hydrochlorothiazide; corresponding reductions with dual therapies ranged from 18.8–24.1/11.7–15.5, 19.0–25.1/12.0–16.0 and 18.3–22.6/11.1–14.3 mm Hg (P⩽0.01, all comparisons of triple versus dual therapy). Treatment with amlodipine/valsartan/hydrochlorothiazide maintained full 24-h effectiveness, including during the morning hours; all hourly mean ambulatory SBP and mean ambulatory DBP measurements were ⩽130/85 mm Hg at end point. Amlodipine/valsartan/hydrochlorothiazide combination therapy was well tolerated. Once-daily treatment with amlodipine/valsartan/hydrochlorothiazide (10/320/25 mg) reduces ABP to a significantly greater extent than component-based dual therapy and maintains its effectiveness over the entire 24-h dosing period

    Antibacterial Characterization of Novel Synthetic Thiazole Compounds against Methicillin-Resistant Staphylococcus pseudintermedius

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    Staphylococcus pseudintermedius is a commensal organism of companion animals that is a significant source of opportunistic infections in dogs. With the emergence of clinical isolates of S. pseudintermedius (chiefly methicillin-resistant S. pseudintermedius (MRSP)) exhibiting increased resistance to nearly all antibiotic classes, new antimicrobials and therapeutic strategies are urgently needed. Thiazole compounds have been previously shown to possess potent antibacterial activity against multidrug-resistant strains of Staphylococcus aureus of human and animal concern. Given the genetic similarity between S. aureus and S. pseudintermedius, this study explores the potential use of thiazole compounds as novel antibacterial agents against methicillin-sensitive S. pseudintermedius (MSSP) and MRSP. A broth microdilution assay confirmed these compounds exhibit potent bactericidal activity (at sub-microgram/mL concentrations) against both MSSA and MRSP clinical isolates while the MTS assay confirmed three compounds (at 10 μg/mL) were not toxic to mammalian cells. A time-kill assay revealed two derivatives rapidly kill MRSP within two hours. However, this rapid bactericidal activity was not due to disruption of the bacterial cell membrane indicating an alternative mechanism of action for these compounds against MRSP. A multistep resistance selection analysis revealed compounds 4 and 5 exhibited a modest (twofold) shift in activity over ten passages. Furthermore, all six compounds (at a subinihibitory concentration) demonstrated the ability to re-sensitize MRSP to oxacillin, indicating these compounds have potential use for extending the therapeutic utility of β-lactam antibiotics against MRSP. Metabolic stability analysis with dog liver microsomes revealed compound 3 exhibited an improved physicochemical profile compared to the lead compound. In addition to this, all six thiazole compounds possessed a long post-antibiotic effect (at least 8 hours) against MRSP. Collectively the present study demonstrates these synthetic thiazole compounds possess potent antibacterial activity against both MSSP and MRSP and warrant further investigation into their use as novel antimicrobial agents

    A finite strain fibre-reinforced viscoelasto-viscoplastic model of plant cell wall growth

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    A finite strain fibre-reinforced viscoelasto-viscoplastic model implemented in a finite element (FE) analysis is presented to study the expansive growth of plant cell walls. Three components of the deformation of growing cell wall, i.e. elasticity, viscoelasticity and viscoplasticity-like growth, are modelled within a consistent framework aiming to present an integrative growth model. The two aspects of growth—turgor-driven creep and new material deposition—and the interplay between them are considered by presenting a yield function, flow rule and hardening law. A fibre-reinforcement formulation is used to account for the role of cellulose microfibrils in the anisotropic growth. Mechanisms in in vivo growth are taken into account to represent the corresponding biologycontrolled behaviour of a cell wall. A viscoelastic formulation is proposed to capture the viscoelastic response in the cell wall. The proposed constitutive model provides a unique framework for modelling both the in vivo growth of cell wall dominated by viscoplasticity-like behaviour and in vitro deformation dominated by elastic or viscoelastic responses. A numerical scheme is devised, and FE case studies are reported and compared with experimental data

    Regional Management Units for Marine Turtles: A Novel Framework for Prioritizing Conservation and Research across Multiple Scales

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    Background: Resolving threats to widely distributed marine megafauna requires definition of the geographic distributions of both the threats as well as the population unit(s) of interest. In turn, because individual threats can operate on varying spatial scales, their impacts can affect different segments of a population of the same species. Therefore, integration of multiple tools and techniques - including site-based monitoring, genetic analyses, mark-recapture studies and telemetry - can facilitate robust definitions of population segments at multiple biological and spatial scales to address different management and research challenges. Methodology/Principal Findings: To address these issues for marine turtles, we collated all available studies on marine turtle biogeography, including nesting sites, population abundances and trends, population genetics, and satellite telemetry. We georeferenced this information to generate separate layers for nesting sites, genetic stocks, and core distributions of population segments of all marine turtle species. We then spatially integrated this information from fine-to coarse-spatial scales to develop nested envelope models, or Regional Management Units (RMUs), for marine turtles globally. Conclusions/Significance: The RMU framework is a solution to the challenge of how to organize marine turtles into units of protection above the level of nesting populations, but below the level of species, within regional entities that might be on independent evolutionary trajectories. Among many potential applications, RMUs provide a framework for identifying data gaps, assessing high diversity areas for multiple species and genetic stocks, and evaluating conservation status of marine turtles. Furthermore, RMUs allow for identification of geographic barriers to gene flow, and can provide valuable guidance to marine spatial planning initiatives that integrate spatial distributions of protected species and human activities. In addition, the RMU framework - including maps and supporting metadata - will be an iterative, user-driven tool made publicly available in an online application for comments, improvements, download and analysis
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