857 research outputs found
Robust diagnostic genetic testing using solution capture enrichment and a novel variant-filtering interface.
Targeted hybridization enrichment prior to next-generation sequencing is a widespread method for characterizing sequence variation in a research setting, and is being adopted by diagnostic laboratories. However, the number of variants identified can overwhelm clinical laboratories with strict time constraints, the final interpretation of likely pathogenicity being a particular bottleneck. To address this, we have developed an approach in which, after automatic variant calling on a standard unix pipeline, subsequent variant filtering is performed interactively, using AgileExomeFilter and AgilePindelFilter (http://dna.leeds.ac.uk/agile), tools designed for clinical scientists with standard desktop computers. To demonstrate the method's diagnostic efficacy, we tested 128 patients using (1) a targeted capture of 36 cancer-predisposing genes or (2) whole-exome capture for diagnosis of the genetically heterogeneous disorder primary ciliary dyskinesia (PCD). In the cancer cohort, complete concordance with previous diagnostic data was achieved across 793 variant genotypes. A high yield (42%) was also achieved for exome-based PCD diagnosis, underscoring the scalability of our method. Simple adjustments to the variant filtering parameters further allowed the identification of a homozygous truncating mutation in a presumptive new PCD gene, DNAH8. These tools should allow diagnostic laboratories to expand their testing portfolios flexibly, using a standard set of reagents and techniques
The kinases MSK1 and MSK2 act as negative regulators of Toll-like receptor signaling
The kinases MSK1 and MSK2 are activated 'downstream' of the p38 and Erk1/2 mitogen-activated protein kinases. Here we found that MSK1 and MSK2 were needed to limit the production of proinflammatory cytokines in response to stimulation of primary macrophages with lipopolysaccharide. By inducing transcription of the mitogen-activated protein kinase phosphatase DUSP1 and the anti-inflammatory cytokine interleukin 10, MSK1 and MSK2 exerted many negative feedback mechanisms. Deficiency in MSK1 and MSK2 prevented the binding of phosphorylated transcription factors CREB and ATF1 to the promoters of the genes encoding interleukin 10 and DUSP1. Mice doubly deficient in MSK1 and MSK2 were hypersensitive to lipopolysaccharide-induced endotoxic shock and showed prolonged inflammation in a model of toxic contact eczema induced by phorbol 12-myristate 13-acetate. Our results establish MSK1 and MSK2 as key components of negative feedback mechanisms needed to limit Toll-like receptor-driven inflammation.</p
Altered Neurocircuitry in the Dopamine Transporter Knockout Mouse Brain
The plasma membrane transporters for the monoamine neurotransmitters dopamine, serotonin, and norepinephrine modulate the dynamics of these monoamine neurotransmitters. Thus, activity of these transporters has significant consequences for monoamine activity throughout the brain and for a number of neurological and psychiatric disorders. Gene knockout (KO) mice that reduce or eliminate expression of each of these monoamine transporters have provided a wealth of new information about the function of these proteins at molecular, physiological and behavioral levels. In the present work we use the unique properties of magnetic resonance imaging (MRI) to probe the effects of altered dopaminergic dynamics on meso-scale neuronal circuitry and overall brain morphology, since changes at these levels of organization might help to account for some of the extensive pharmacological and behavioral differences observed in dopamine transporter (DAT) KO mice. Despite the smaller size of these animals, voxel-wise statistical comparison of high resolution structural MR images indicated little morphological change as a consequence of DAT KO. Likewise, proton magnetic resonance spectra recorded in the striatum indicated no significant changes in detectable metabolite concentrations between DAT KO and wild-type (WT) mice. In contrast, alterations in the circuitry from the prefrontal cortex to the mesocortical limbic system, an important brain component intimately tied to function of mesolimbic/mesocortical dopamine reward pathways, were revealed by manganese-enhanced MRI (MEMRI). Analysis of co-registered MEMRI images taken over the 26 hours after introduction of Mn^(2+) into the prefrontal cortex indicated that DAT KO mice have a truncated Mn^(2+) distribution within this circuitry with little accumulation beyond the thalamus or contralateral to the injection site. By contrast, WT littermates exhibit Mn^(2+) transport into more posterior midbrain nuclei and contralateral mesolimbic structures at 26 hr post-injection. Thus, DAT KO mice appear, at this level of anatomic resolution, to have preserved cortico-striatal-thalamic connectivity but diminished robustness of reward-modulating circuitry distal to the thalamus. This is in contradistinction to the state of this circuitry in serotonin transporter KO mice where we observed more robust connectivity in more posterior brain regions using methods identical to those employed here
Chronic non-specific low back pain - sub-groups or a single mechanism?
Copyright 2008 Wand and O'Connell; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0),
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background: Low back pain is a substantial health problem and has subsequently attracted a
considerable amount of research. Clinical trials evaluating the efficacy of a variety of interventions
for chronic non-specific low back pain indicate limited effectiveness for most commonly applied
interventions and approaches.
Discussion: Many clinicians challenge the results of clinical trials as they feel that this lack of
effectiveness is at odds with their clinical experience of managing patients with back pain. A
common explanation for this discrepancy is the perceived heterogeneity of patients with chronic
non-specific low back pain. It is felt that the effects of treatment may be diluted by the application
of a single intervention to a complex, heterogeneous group with diverse treatment needs. This
argument presupposes that current treatment is effective when applied to the correct patient.
An alternative perspective is that the clinical trials are correct and current treatments have limited
efficacy. Preoccupation with sub-grouping may stifle engagement with this view and it is important
that the sub-grouping paradigm is closely examined. This paper argues that there are numerous
problems with the sub-grouping approach and that it may not be an important reason for the
disappointing results of clinical trials. We propose instead that current treatment may be ineffective
because it has been misdirected. Recent evidence that demonstrates changes within the brain in
chronic low back pain sufferers raises the possibility that persistent back pain may be a problem of
cortical reorganisation and degeneration. This perspective offers interesting insights into the
chronic low back pain experience and suggests alternative models of intervention.
Summary: The disappointing results of clinical research are commonly explained by the failure of
researchers to adequately attend to sub-grouping of the chronic non-specific low back pain
population. Alternatively, current approaches may be ineffective and clinicians and researchers may
need to radically rethink the nature of the problem and how it should best be managed
Polymerase δ replicates both strands after homologous recombination-dependent fork restart
To maintain genetic stability DNA must be replicated only once and replication completed even when individual replication forks are inactivated. Because fork inactivation is common, the passive convergence of an adjacent fork is insufficient to rescue all inactive forks. Thus, eukaryotic cells have evolved homologous recombination-dependent mechanisms to restart persistent inactive forks. Completing DNA synthesis via Homologous Recombination Restarted Replication (HoRReR) ensures cell survival, but at a cost. One such cost is increased mutagenesis caused by HoRReR being more error prone than canonical replication. This increased error rate implies that the HoRReR mechanism is distinct from that of a canonical fork. Here we exploit the fission yeast Schizosaccharomyces pombe to demonstrate that a DNA sequence duplicated by HoRReR during S phase is replicated semi-conservatively, but that both the leading and lagging strands are synthesised by DNA polymerase delta
Deciphering the Complex Distribution of Human Immunodeficiency Virus Type 1 Subtypes among Different Cohorts in Northern Tanzania.
Increased understanding of the genetic diversity of HIV-1 is challenging but important in the development of an effective vaccine. We aimed to describe the distribution of HIV-1 subtypes in northern Tanzania among women enrolled in studies preparing for HIV-1 prevention trials (hospitality facility-worker cohorts), and among men and women in an open cohort demographic surveillance system (Kisesa cohort). The polymerase encompassing partial reverse transcriptase was sequenced and phylogenetic analysis performed and subtype determined. Questionnaires documented demographic data. We examined factors associated with subtype using multinomial logistic regression, adjusted for study, age, and sex. Among 140 individuals (125 women and 15 men), subtype A1 predominated (54, 39%), followed by C (46, 33%), D (25, 18%) and unique recombinant forms (URFs) (15, 11%). There was weak evidence to suggest different subtype frequencies by study (for example, 18% URFs in the Kisesa cohort versus 5-9% in the hospitality facility-worker cohorts; adjusted relative-risk ratio (aRR) = 2.35 [95% CI 0.59,9.32]; global p = 0.09). Compared to men, women were less likely to have subtype D versus A (aRR = 0.12 [95% CI 0.02,0.76]; global p = 0.05). There was a trend to suggest lower relative risk of subtype D compared to A with older age (aRR = 0.44 [95% CI 0.23,0.85] per 10 years; global p = 0.05). We observed multiple subtypes, confirming the complex genetic diversity of HIV-1 strains circulating in northern Tanzania, and found some differences between cohorts and by age and sex. This has important implications for vaccine design and development, providing opportunity to determine vaccine efficacy in diverse HIV-1 strains
The Formation of the First Massive Black Holes
Supermassive black holes (SMBHs) are common in local galactic nuclei, and
SMBHs as massive as several billion solar masses already exist at redshift z=6.
These earliest SMBHs may grow by the combination of radiation-pressure-limited
accretion and mergers of stellar-mass seed BHs, left behind by the first
generation of metal-free stars, or may be formed by more rapid direct collapse
of gas in rare special environments where dense gas can accumulate without
first fragmenting into stars. This chapter offers a review of these two
competing scenarios, as well as some more exotic alternative ideas. It also
briefly discusses how the different models may be distinguished in the future
by observations with JWST, (e)LISA and other instruments.Comment: 47 pages with 306 references; this review is a chapter in "The First
Galaxies - Theoretical Predictions and Observational Clues", Springer
Astrophysics and Space Science Library, Eds. T. Wiklind, V. Bromm & B.
Mobasher, in pres
Genetic and neurological foundations of customer orientation: field and experimental evidence
We explore genetic and neurological bases for customer orientation (CO) and contrast them with sales orientation (SO). Study 1 is a field study that establishes that CO, but not SO, leads to greater opportunity recognition. Study 2 examines genetic bases for CO and finds that salespeople with CO are more likely to have the 7R variant of the DRD4 gene. This is consistent with basic research on dopamine receptor activity in the brain that underlies novelty seeking, the reward function, and risk taking. Study 3 examines the neural basis of CO and finds that salespeople with CO, but not SO, experience greater activation of their mirror neuron systems and neural processes associated with empathy. Managerial and research implications are discussed
Multi-messenger observations of a binary neutron star merger
On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta
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