135 research outputs found

    A phylogenomic approach reveals a low somatic mutation rate in a long-lived plant.

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    Somatic mutations can have important effects on the life history, ecology, and evolution of plants, but the rate at which they accumulate is poorly understood and difficult to measure directly. Here, we develop a method to measure somatic mutations in individual plants and use it to estimate the somatic mutation rate in a large, long-lived, phenotypically mosaic Eucalyptus melliodora tree. Despite being 100 times larger than Arabidopsis, this tree has a per-generation mutation rate only ten times greater, which suggests that this species may have evolved mechanisms to reduce the mutation rate per unit of growth. This adds to a growing body of evidence that illuminates the correlated evolutionary shifts in mutation rate and life history in plants

    Machine learningā€“based biomarker profile derived from 4210 serially measured proteins predicts clinical outcome of patients with heart failure

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    Aims Risk assessment tools are needed for timely identification of patients with heart failure (HF) with reduced ejection fraction (HFrEF) who are at high risk of adverse events. In this study, we aim to derive a small set out of 4210 repeatedly measured proteins, which, along with clinical characteristics and established biomarkers, carry optimal prognostic capacity for adverse events, in patients with HFrEF. Methods and results In 382 patients, we performed repeated blood sampling (median follow-up: 2.1 years) and applied an aptamer-based multiplex proteomic approach. We used machine learning to select the optimal set of predictors for the primary endpoint (PEP: composite of cardiovascular death, heart transplantation, left ventricular assist device implantation, and HF hospitalization). The association between repeated measures of selected proteins and PEP was investigated by multivariable joint models. Internal validation (cross-validated c-index) and external validation (Henry Ford HF PharmacoGenomic Registry cohort) were performed. Nine proteins were selected in addition to the MAGGIC risk score, N-terminal pro-hormone B-type natriuretic peptide, and troponin T: suppression of tumourigenicity 2, tryptophanyl-tRNA synthetase cytoplasmic, histone H2A Type 3, angiotensinogen, deltex-1, thrombospondin-4, ADAMTS-like protein 2, anthrax toxin receptor 1, and cathepsin D. N-terminal pro-hormone B-type natriuretic peptide and angiotensinogen showed the strongest associations [hazard ratio (95% confidence interval): 1.96 (1.17ā€“3.40) and 0.66 (0.49ā€“0.88), respectively]. The multivariable model yielded a c-index of 0.85 upon internal validation and c-indices up to 0.80 upon external validation. The c-index was higher than that of a model containing established risk factors (P = 0.021). Conclusion Nine serially measured proteins captured the most essential prognostic information for the occurrence of adverse events in patients with HFrEF, and provided incremental value for HF prognostication beyond established risk factors. These proteins could be used for dynamic, individual risk assessment in a prospective setting. These findings also illustrate the potential value of relatively ā€˜novelā€™ biomarkers for prognostication.</p

    Whatā€™s Next for Acute Heart Failure Research?

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    Each year over one million patients with acute heart failure (AHF) present to a United States emergency department (ED). The vast majority are hospitalized for further management. The length of stay and high postdischarge event rate in this cohort have changed little over the past decade. Therapeutic trials have failed to yield substantive improvement in postdischarge outcomes; subsequently, AHF care has changed little in the past 40 years. Prior research studies have been fragmented as either ā€œinpatientā€ or ā€œED-based.ā€ Recognizing the challenges in identification and enrollment of ED patients with AHF, and the lack of robust evidence to guide management, an AHF clinical trials network was developed. This network has demonstrated, through organized collaboration between cardiology and emergency medicine, that many of the hurdles in AHF research can be overcome. The development of a network that supports the collaboration of acute care and HF researchers, combined with the availability of federally funded infrastructure, will facilitate more efficient conduct of both explanatory and pragmatic trials in AHF. Yet many important questions remain, and in this document our group of emergency medicine and cardiology investigators have identified four high-priority research areas

    Multi-locus phylogeny and species delimitation of Australo-Papuan blacksnakes (Pseudechis Wagler, 1830: Elapidae: Serpentes)

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    Genetic analyses of Australasian organisms have resulted in the identification of extensive cryptic diversity across the continent. The venomous elapid snakes are among the best-studied organismal groups in this region, but many knowledge gaps persist: for instance, despite their iconic status, the species-level diversity among Australo-Papuan blacksnakes (Pseudechis) has remained poorly understood due to the existence of a group of cryptic species within the P. australis species complex, collectively termed ā€˜ā€˜pygmy mulga snakesā€. Using two mitochondrial and three nuclear loci we assess species boundaries within the genus using Bayesian species delimitation methods and reconstruct their phylogenetic history using multispecies coalescent approaches. Our analyses support the recognition of 10 species, including all of the currently described pygmy mulga snakes and one undescribed species from the Northern Territory of Australia. Phylogenetic relationships within the genus are broadly consistent with previous work, with the recognition of three major groups, the viviparous red-bellied black snake P. porphyriacus forming the sister species to two clades consisting of ovoviviparous specie

    Cause of Death in Patients With Acute Heart Failure: Insights From RELAX-AHF-2

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    OBJECTIVES: This study sought to better understand the discrepant results of 2 trials of serelaxin on acute heart failure (AHF) and short-term mortality after AHF by analyzing causes of death of patients in the RELAX-AHF-2 (Efficacy, Safety and Tolerability of Serelaxin When Added to Standard Therapy in AHF-2) trial. BACKGROUND: Patients with AHF continue to suffer significant short-term mortality, but limited systematic analyses of causes of death in this patient population are available. METHODS: Adjudicated cause of death of patients in RELAX-AHF-2, a randomized, double-blind, placebo-controlled trial of serelaxin in patients with AHF across the spectrum of ejection fraction (EF), was analyzed. RESULTS: By 180 days of follow-up, 11.5% of patients in RELAX-AHF-2 died, primarily due to heart failure (HF) (38% of all deaths). Unlike RELAX-AHF, there was no apparent effect of treatment with serelaxin on any category of cause of death. Older patients (ā‰„75 years) had higher rates of mortality (14.2% vs. 8.8%) and noncardiovascular (CV) death (27% vs. 19%) compared to younger patients. Patients with preserved EF (ā‰„50%) had lower rates of HF-related mortality (30% vs. 40%) but higher non-CV mortality (36% vs. 20%) compared to patients with reduced EF. CONCLUSIONS: Despite previous data suggesting benefit of serelaxin in AHF, treatment with serelaxin was not found to improve overall mortality or have an effect on any category of cause of death in RELAX-AHF-2. Careful adjudication of events in the serelaxin trials showed that older patients and those with preserved EF had fewer deaths from HF or sudden death and more deaths from other CV causes and from noncardiac causes. (Efficacy, Safety and Tolerability of Serelaxin When Added to Standard Therapy in AHF [RELAX-AHF-2]; NCT01870778)

    Cause of Death in Patients With Acute Heart Failure Insights From RELAX-AHF-2

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    OBJECTIVES: This study sought to better understand the discrepant results of 2 trials of serelaxin on acute heart failure (AHF) and short-term mortality after AHF by analyzing causes of death of patients in the RELAX-AHF-2 (Efficacy, Safety and Tolerability of Serelaxin When Added to Standard Therapy in AHF-2) trial. BACKGROUND: Patients with AHF continue to suffer significant short-term mortality, but limited systematic analyses of causes of death in this patient population are available. METHODS: Adjudicated cause of death of patients in RELAX-AHF-2, a randomized, double-blind, placebo-controlled trial of serelaxin in patients with AHF across the spectrum of ejection fraction (EF), was analyzed. RESULTS: By 180 days of follow-up, 11.5% of patients in RELAX-AHF-2 died, primarily due to heart failure (HF) (38% of all deaths). Unlike RELAX-AHF, there was no apparent effect of treatment with serelaxin on any category of cause of death. Older patients (ā‰„75 years) had higher rates of mortality (14.2% vs. 8.8%) and noncardiovascular (CV) death (27% vs. 19%) compared to younger patients. Patients with preserved EF (ā‰„50%) had lower rates of HF-related mortality (30% vs. 40%) but higher non-CV mortality (36% vs. 20%) compared to patients with reduced EF. CONCLUSIONS: Despite previous data suggesting benefit of serelaxin in AHF, treatment with serelaxin was not found to improve overall mortality or have an effect on any category of cause of death in RELAX-AHF-2. Careful adjudication of events in the serelaxin trials showed that older patients and those with preserved EF had fewer deaths from HF or sudden death and more deaths from other CV causes and from noncardiac causes. (Efficacy, Safety and Tolerability of Serelaxin When Added to Standard Therapy in AHF [RELAX-AHF-2]; NCT01870778)

    Interaction between PPARA genotype and Ī²-blocker treatment influences clinical outcomes following acute coronary syndromes

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    Ī²-blockers (BB) are strongly recommended after an acute coronary syndrome (ACS), although all patients may not benefit. Causes for variable patient responses to BB are unknown. Given that myocardial ischemia and BB influence metabolic processes regulated by peroxisome proliferator-activated receptor Ī± (PPARĪ±), we hypothesized that interactions between polymorphisms of the PPARĪ± gene (PPARA) and BB treatment would influence clinical outcome following ACS

    Shaping a screening file for maximal lead discovery efficiency and effectiveness: elimination of molecular redundancy

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    High Throughput Screening (HTS) is a successful strategy for finding hits and leads that have the opportunity to be converted into drugs. In this paper we highlight novel computational methods used to select compounds to build a new screening file at Pfizer and the analytical methods we used to assess their quality. We also introduce the novel concept of molecular redundancy to help decide on the density of compounds required in any region of chemical space in order to be confident of running successful HTS campaigns

    Next-generation mitogenomics: A comparison of approaches applied to caecilian amphibian phylogeny

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    Mitochondrial genome (mitogenome) sequences are being generated with increasing speed due to the advances of next-generation sequencing (NGS) technology and associated analytical tools. However, detailed comparisons to explore the utility of alternative NGS approaches applied to the same taxa have not been undertaken. We compared a 'traditional' Sanger sequencing method with two NGS approaches (shotgun sequencing and non-indexed, multiplex amplicon sequencing) on four different sequencing platforms (Illumina's HiSeq and MiSeq, Roche's 454 GS FLX, and Life Technologies' Ion Torrent) to produce seven (near-) complete mitogenomes from six species that form a small radiation of caecilian amphibians from the Seychelles. The fastest, most accurate method of obtaining mitogenome sequences that we tested was direct sequencing of genomic DNA (shotgun sequencing) using the MiSeq platform. Bayesian inference and maximum likelihood analyses using seven different partitioning strategies were unable to resolve compellingly all phylogenetic relationships among the Seychelles caecilian species, indicating the need for additional data in this case
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