1,440 research outputs found
Short-Term Relapse Quantitation as a Fully Surrogate Endpoint for Long-Term Sustained Progression of Disability in RRMS Patients Treated with Natalizumab
Time to sustained worsening in the expanded disability status scale as the standard for evaluating the accumulation of disability has been used as a measure of clinical efficacy in many relapsing-remitting multiple sclerosis (RRMS) clinical trials. However, this measurement usually requires a large sample and long-term study to demonstrate the treatment effect. Annualized relapse rate or time to first relapse is also widely used as alternative measurements of clinical efficacy. A formal statistical validation of short-term relapse activity as a surrogate endpoint for long-term sustained progression of disability could potentially permit smaller, shorter, and less expensive clinical trials in RRMS. Four statistical validation/evaluation approaches consistently showed that relapse activity through one year of treatment serves as statistically valid surrogate endpoint for time to sustained progression of disability. The analysis demonstrates that long-term sustained progression of disability can be predicted by short-term relapse measures with 4 consistent validations of statistical approaches, including a formal statistical hypothesis test. This was demonstrated in a large phase III trial of natalizumab and showed that the beneficial clinical effect of natalizumab on sustained progression of disability at 2 years in patients with RRMS can be predicted by the total number of relapses at 1 year
Parameterized Complexity of the k-anonymity Problem
The problem of publishing personal data without giving up privacy is becoming
increasingly important. An interesting formalization that has been recently
proposed is the -anonymity. This approach requires that the rows of a table
are partitioned in clusters of size at least and that all the rows in a
cluster become the same tuple, after the suppression of some entries. The
natural optimization problem, where the goal is to minimize the number of
suppressed entries, is known to be APX-hard even when the records values are
over a binary alphabet and , and when the records have length at most 8
and . In this paper we study how the complexity of the problem is
influenced by different parameters. In this paper we follow this direction of
research, first showing that the problem is W[1]-hard when parameterized by the
size of the solution (and the value ). Then we exhibit a fixed parameter
algorithm, when the problem is parameterized by the size of the alphabet and
the number of columns. Finally, we investigate the computational (and
approximation) complexity of the -anonymity problem, when restricting the
instance to records having length bounded by 3 and . We show that such a
restriction is APX-hard.Comment: 22 pages, 2 figure
Modeling genomic diversity and tumor dependency in malignant melanoma
The classification of human tumors based on molecular criteria offers tremendous clinical potential; however, discerning critical and "druggable" effectors on a large scale will also require robust experimental models reflective of tumor genomic diversity. Here, we describe a comprehensive genomic analysis of 101 melanoma short-term cultures and cell lines. Using an analytic approach designed to enrich for putative "driver" events, we show that cultured melanoma cells encompass the spectrum of significant genomic alterations present in primary tumors. When annotated according to these lesions, melanomas cluster into subgroups suggestive of distinct oncogenic mechanisms. Integrating gene expression data suggests novel candidate effector genes linked to recurrent copy gains and losses, including both phosphatase and tensin homologue (PTEN)-dependent and PTEN-independent tumor suppressor mechanisms associated with chromosome 10 deletions. Finally, sample-matched pharmacologic data show that FGFR1 mutations and extracellular signal-regulated kinase (ERK) activation may modulate sensitivity to mitogen-activated protein kinase/ERK kinase inhibitors. Genetically defined cell culture collections therefore offer a rich framework for systematic functional studies in melanoma and other tumors
TRIM5alpha Restricts Flavivirus Replication by Targeting the Viral Protease for Proteasomal Degradation
Tripartite motif-containing protein 5alpha (TRIM5alpha) is a cellular antiviral restriction factor that prevents early events in retrovirus replication. The activity of TRIM5alpha is thought to be limited to retroviruses as a result of highly specific interactions with capsid lattices. In contrast to this current understanding, we show that both human and rhesus macaque TRIM5alpha suppress replication of specific flaviviruses. Multiple viruses in the tick-borne encephalitis complex are sensitive to TRIM5alpha-dependent restriction, but mosquito-borne flaviviruses, including yellow fever, dengue, and Zika viruses, are resistant. TRIM5alpha suppresses replication by binding to the viral protease NS2B/3 to promote its K48-linked ubiquitination and proteasomal degradation. Importantly, TRIM5alpha contributes to the antiviral function of IFN-I against sensitive flaviviruses in human cells. Thus, TRIM5alpha possesses remarkable plasticity in the recognition of diverse virus families, with the potential to influence human susceptibility to emerging flaviviruses of global concern
Sectoral Impacts of Invasive Species in the United States and Approaches to Management
Invasive species have a major effect on many sectors of the U.S. economy and on the well-being of its citizens. Their presence impacts animal and human health, military readiness, urban vegetation and infrastructure, water, energy and transportations systems, and indigenous peoples in the United States (Table 9.1). They alter bio-physical systems and cultural practices and require significant public and private expenditure for control. This chapter provides examples of the impacts to human systems and explains mechanisms of invasive species’ establishment and spread within sectors of the U.S. economy. The chapter is not intended to be comprehensive but rather to provide insight into the range and severity of impacts. Examples provide context for ongoing Federal programs and initiatives and support State and private efforts to prevent the introduction and spread of invasive species and eradicate and control established invasive species
A comparative analysis of algorithms for somatic SNV detection in cancer
Motivation: With the advent of relatively affordable high-throughput technologies, DNA sequencing of cancers is now common practice in cancer research projects and will be increasingly used in clinical practice to inform diagnosis and treatment. Somatic (cancer-only) single nucleotide variants (SNVs) are the simplest class of mutation, yet their identification in DNA sequencing data is confounded by germline polymorphisms, tumour heterogeneity and sequencing and analysis errors. Four recently published algorithms for the detection of somatic SNV sites in matched cancer–normal sequencing datasets are VarScan, SomaticSniper, JointSNVMix and Strelka. In this analysis, we apply these four SNV calling algorithms to cancer–normal Illumina exome sequencing of a chronic myeloid leukaemia (CML) patient. The candidate SNV sites returned by each algorithm are filtered to remove likely false positives, then characterized and compared to investigate the strengths and weaknesses of each SNV calling algorithm. Results: Comparing the candidate SNV sets returned by VarScan, SomaticSniper, JointSNVMix2 and Strelka revealed substantial differences with respect to the number and character of sites returned; the somatic probability scores assigned to the same sites; their susceptibility to various sources of noise; and their sensitivities to low-allelic-fraction candidates.Nicola D. Roberts, R. Daniel Kortschak, Wendy T. Parker, Andreas W. Schreiber, Susan Branford, Hamish S. Scott, Garique Glonek and David L. Adelso
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Dengue viruses cleave STING in humans but not in nonhuman primates, their presumed natural reservoir.
Human dengue viruses emerged from primate reservoirs, yet paradoxically dengue does not reach high titers in primate models. This presents a unique opportunity to examine the genetics of spillover versus reservoir hosts. The dengue virus 2 (DENV2) - encoded protease cleaves human STING, reducing type I interferon production and boosting viral titers in humans. We find that both human and sylvatic (reservoir) dengue viruses universally cleave human STING, but not the STING of primates implicated as reservoir species. The special ability of dengue to cleave STING is thus specific to humans and a few closely related ape species. Conversion of residues 78/79 to the human-encoded 'RG' renders all primate (and mouse) STINGs sensitive to viral cleavage. Dengue viruses may have evolved to increase viral titers in the dense and vast human population, while maintaining decreased titers and pathogenicity in the more rare animals that serve as their sustaining reservoir in nature
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Beyond dis-identification: A discursive approach to self-alienation in contemporary organizations
Dis-identification has become a key research area in organization studies, demonstrating how employees subjectively distance themselves from managerial domination by protecting/constructing their more ‘authentic’ identities. But how should we understand situations where even these ‘real’ selves are experienced as alien and foreign? We revise the theory of self-alienation to explain cases beyond disidentification, where even back-stage identities (‘who we really are’) are considered something polluted, objectified and foreign. Drawing on an illustrative empirical vignette of a consultant, we demonstrate how a revised version of self-alienation might usefully capture experiences of work where the back-stage/front-stage boundary breaks down. We tentatively posit three causes of this self-alienation in relation to contemporary organizations, and discuss their significance in the context of organizational dis identification
Phylogeography of an endangered disjunct herb: long-distance dispersal, refugia and colonization routes
Quaternary glacial cycles appear to have had a consistent role in shaping the genetic diversity and
structure of plant species. Despite the unusual combination of the characteristics of the western Mediterranean–
Macaronesian area, there are no studies that have specifically examined the effects of palaeoclimatic and palaeogeographic
factors on the genetic composition and structure of annual herbs. Astragalus edulis is a disjunct endemic
found in the easternmost Canary Islands and the semi-arid areas of north-eastern Africa and south-eastern Iberian
Peninsula. This endangered species shows no evident adaptations to long-distance dispersal. Amplified fragment
length polymorphism (AFLP) data and plastid DNA sequences were analysed from a total of 360 individuals distributed
throughout the range of this species. The modelled potential distribution of A. edulis under current conditions
was projected over the climatic conditions of the Last Interglacial (130 ka BP) and Last Glacial Maximum (21
ka BP) to analyse changes in habitat suitability and to look for associations between the modelling and genetic
results. Amplified fragment length polymorphism analysis showed clear phylogeographic structure with four distinct
genetic clusters. Approximate Bayesian computation (ABC) models based on plastid DNA sequences indicated a
Middle Pleistocene long-distance dispersal event as the origin of the populations of the Canary Islands. The models
also suggested south-western Morocco as the ancestral area for the species, as well as subsequent colonization of
north-eastern Morocco and the Iberian Peninsula. The data compiled indicated the possibility of the presence of refuge
areas at favourable locations around the High Atlas and Anti-Atlas mountain ranges. Moreover, palaeodistribution
models strongly support the events inferred by ABC modelling and show the potential distribution of the species
in the past, suggesting a putative colonization route.This work has been financed by the Spanish Ministerio
de Ciencia e Innovación through the projects CGL2012-
32574 and REN2003-09427, as well as by the Andalusian
Consejería de Innovación, Ciencia y Tecnología through
the project RNM1067. The funders had no role in study
design, data collection and analysis, decision to publish
or preparation of the manuscript
The collapse of intermediate structures?
How can we explain the rise of President Trump and the attraction of his campaign behavior before and since he took office? We argue here that the collapse of ‘intermediate structures’ has been a key factor; that the associations and groups which are building blocks of pluralistic politics have been eroded to such an extent that Trump’s personality politics have been able to take over the political stage
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