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- Hart, R. G., et al.
(författare)
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Rivaroxaban for Stroke Prevention after Embolic Stroke of Undetermined Source
- 2018
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Ingår i: New England Journal of Medicine. - 0028-4793 .- 1533-4406. ; 378:23, s. 2191-2201
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND Embolic strokes of undetermined source represent 20% of ischemic strokes and are associated with a high rate of recurrence. Anticoagulant treatment with rivaroxaban, an oral factor Xa inhibitor, may result in a lower risk of recurrent stroke than aspirin. We compared the efficacy and safety of rivaroxaban (at a daily dose of 15 mg) with aspirin (at a daily dose of 100 mg) for the prevention of recurrent stroke in patients with recent ischemic stroke that was presumed to be from cerebral embolism but without arterial stenosis, lacune, or an identified cardioembolic source. The primary efficacy outcome was the first recurrence of ischemic or hemorrhagic stroke or systemic embolism in a time-to-event analysis; the primary safety outcome was the rate of major bleeding. A total of 7213 participants were enrolled at 459 sites; 3609 patients were randomly assigned to receive rivaroxaban and 3604 to receive aspirin. Patients had been followed for a median of 11 months when the trial was terminated early because of a lack of benefit with regard to stroke risk and because of bleeding associated with rivaroxaban. The primary efficacy outcome occurred in 172 patients in the rivaroxaban group (annualized rate, 5.1%) and in 160 in the aspirin group (annualized rate, 4.8%) (hazard ratio, 1.07; 95% confidence interval [CI], 0.87 to 1.33; P=0.52). Recurrent ischemic stroke occurred in 158 patients in the rivaroxaban group (annualized rate, 4.7%) and in 156 in the aspirin group (annualized rate, 4.7%). Major bleeding occurred in 62 patients in the rivaroxaban group (annualized rate, 1.8%) and in 23 in the aspirin group (annualized rate, 0.7%) (hazard ratio, 2.72; 95% CI, 1.68 to 4.39; P<0.001). Rivaroxaban was not superior to aspirin with regard to the prevention of recurrent stroke after an initial embolic stroke of undetermined source and was associated with a higher risk of bleeding.
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- Seiffge, D. J., et al.
(författare)
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Recanalization Therapies in Acute Ischemic Stroke Patients Impact of Prior Treatment With Novel Oral Anticoagulants on Bleeding Complications and Outcome A Pilot Study
- 2015
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Ingår i: Circulation. - : Ovid Technologies (Wolters Kluwer Health). - 0009-7322 .- 1524-4539. ; 132:13, s. 1261-1269
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Tidskriftsartikel (refereegranskat)abstract
- Background-We explored the safety of intravenous thrombolysis (IVT) or intra-arterial treatment (IAT) in patients with ischemic stroke on non-vitamin K antagonist oral anticoagulants (NOACs, last intake <48 hours) in comparison with patients (1) taking vitamin K antagonists (VKAs) or (2) without previous anticoagulation (no-OAC). Methods and Results-This is a multicenter cohort pilot study. Primary outcome measures were (1) occurrence of intracranial hemorrhage (ICH) in 3 categories: any ICH (ICH any), symptomatic ICH according to the criteria of the European Cooperative Acute Stroke Study II (ECASS-II) (sICH ECASS-II) and the National Institute of Neurological Disorders and Stroke (NINDS) thrombolysis trial (sICH NINDS); and (2) death (at 3 months). Cohorts were compared by using propensity score matching. Our NOAC cohort comprised 78 patients treated with IVT/IAT and the comparison groups of 441 VKA patients and 8938 no-OAC patients. The median time from last NOAC intake to IVT/IAT was 13 hours (interquartile range, 8-22 hours). In VKA patients, median pre-IVT/IAT international normalized ratio was 1.3 (interquartile range, 1.1-1.6). ICH any was observed in 18.4% NOAC patients versus 26.8% in VKA patients and 17.4% in no-OAC patients. sICH ECASS-II and sICH NINDS occurred in 2.6%/3.9% NOAC patients, in comparison with 6.5%/9.3% of VKA patients and 5.0%/7.2% of no-OAC patients, respectively. At 3 months, 23.0% of NOAC patients in comparison with 26.9% of VKA patients and 13.9% of no-OAC patients had died. Propensity score matching revealed no statistically significant differences. Conclusions-IVT/IAT in selected patients with ischemic stroke under NOAC treatment has a safety profile similar to both IVT/IAT in patients on subtherapeutic VKA treatment or in those without previous anticoagulation. However, further prospective studies are needed, including the impact of specific coagulation tests.
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- Edwards, Robert A., et al.
(författare)
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Global phylogeography and ancient evolution of the widespread human gut virus crAssphage
- 2019
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Ingår i: Nature Microbiology. - : Springer Science and Business Media LLC. - 2058-5276. ; 4:10, s. 1727-1736
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Tidskriftsartikel (refereegranskat)abstract
- Microbiomes are vast communities of microorganisms and viruses that populate all natural ecosystems. Viruses have been considered to be the most variable component of microbiomes, as supported by virome surveys and examples of high genomic mosaicism. However, recent evidence suggests that the human gut virome is remarkably stable compared with that of other environments. Here, we investigate the origin, evolution and epidemiology of crAssphage, a widespread human gut virus. Through a global collaboration, we obtained DNA sequences of crAssphage from more than one-third of the world's countries and showed that the phylogeography of crAssphage is locally clustered within countries, cities and individuals. We also found fully colinear crAssphage-like genomes in both Old-World and New-World primates, suggesting that the association of crAssphage with primates may be millions of years old. Finally, by exploiting a large cohort of more than 1,000 individuals, we tested whether crAssphage is associated with bacterial taxonomic groups of the gut microbiome, diverse human health parameters and a wide range of dietary factors. We identified strong correlations with different clades of bacteria that are related to Bacteroidetes and weak associations with several diet categories, but no significant association with health or disease. We conclude that crAssphage is a benign cosmopolitan virus that may have coevolved with the human lineage and is an integral part of the normal human gut virome.
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- van Duijn, Esther, et al.
(författare)
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Native Tandem and Ion Mobility Mass Spectrometry Highlight Structural and Modular Similarities in Clustered-Regularly-Interspaced Shot-Palindromic-Repeats (CRISPR)-associated Protein Complexes From Escherichia coli and Pseudomonas aeruginosa
- 2012
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Ingår i: Molecular & Cellular Proteomics. - 1535-9476 .- 1535-9484. ; 11:11, s. 1430-1441
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Tidskriftsartikel (refereegranskat)abstract
- The CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated genes) immune system of bacteria and archaea provides acquired resistance against viruses and plasmids, by a strategy analogous to RNA-interference. Key components of the defense system are ribonucleoprotein complexes, the composition of which appears highly variable in different CRISPR/Cas subtypes. Previous studies combined mass spectrometry, electron microscopy, and small angle x-ray scattering to demonstrate that the E. coli Cascade complex (405 kDa) and the P. aeruginosa Csy-complex (350 kDa) are similar in that they share a central spiral-shaped hexameric structure, flanked by associating proteins and one CRISPR RNA. Recently, a cryo-electron microscopy structure of Cascade revealed that the CRISPR RNA molecule resides in a groove of the hexameric backbone. For both complexes we here describe the use of native mass spectrometry in combination with ion mobility mass spectrometry to assign a stable core surrounded by more loosely associated modules. Via computational modeling subcomplex structures were proposed that relate to the experimental IMMS data. Despite the absence of obvious sequence homology between several subunits, detailed analysis of sub-complexes strongly suggests analogy between subunits of the two complexes. Probing the specific association of E. coli Cascade/crRNA to its complementary DNA target reveals a conformational change. All together these findings provide relevant new information about the potential assembly process of the two CRISPR-associated complexes.
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- Brouns, Stan J, et al.
(författare)
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Small CRISPR RNAs guide antiviral defense in prokaryotes
- 2008
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 321:5891, s. 960-964
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Tidskriftsartikel (refereegranskat)abstract
- Prokaryotes acquire virus resistance by integrating short fragments of viral nucleic acid into clusters of regularly interspaced short palindromic repeats (CRISPRs). Here we show how virus-derived sequences contained in CRISPRs are used by CRISPR-associated (Cas) proteins from the host to mediate an antiviral response that counteracts infection. After transcription of the CRISPR, a complex of Cas proteins termed Cascade cleaves a CRISPR RNA precursor in each repeat and retains the cleavage products containing the virus-derived sequence. Assisted by the helicase Cas3, these mature CRISPR RNAs then serve as small guide RNAs that enable Cascade to interfere with virus proliferation. Our results demonstrate that the formation of mature guide RNAs by the CRISPR RNA endonuclease subunit of Cascade is a mechanistic requirement for antiviral defense.
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- van der Oost, John, et al.
(författare)
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CRISPR-based adaptive and heritable immunity in prokaryotes
- 2009
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Ingår i: TIBS -Trends in Biochemical Sciences. Regular ed.. - : Elsevier BV. - 0968-0004 .- 1362-4326. ; 34:8, s. 401-407
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Forskningsöversikt (refereegranskat)abstract
- The recently discovered CRISPR (clustered regularly interspaced short palindromic repeat) defense system protects bacteria and archaea against mobile genetic elements. This immunity system has the potential to continuously adjust its reach at the genomic level, implying that both gain and loss of information is inheritable. The CRISPR system consists of typical stretches of interspaced repetitive DNA (CRISPRs) and associated cas genes. Three distinct stages are recognized in the CRISPR defense mechanism: (i) adaptation of the CRISPR via the integration of short sequences of the invaders as spacers; (ii) expression of CRISPRs and subsequent processing to small guide RNAs; and (iii) interference of target DNA by the crRNA guides. Recent analyses of key Cas proteins indicate that, despite some functional analogies, this fascinating prokaryotic system shares no phylogenetic relation with the eukaryotic RNA interference system.
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- Volger, R., et al.
(författare)
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Mining moon & mars with microbes : Biological approaches to extract iron from Lunar and Martian regolith
- 2020
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Ingår i: Planetary and Space Science. - : Elsevier. - 0032-0633 .- 1873-5088. ; 184
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Tidskriftsartikel (refereegranskat)abstract
- The logistical supply of terrestrial materials to space is costly and puts limitations on exploration mission scenarios. In-situ resource utilization (ISRU) can alleviate logistical requirements and thus enables sustainable exploration of space. In this paper, a novel approach to ISRU, utilizing microorganisms to extract iron from Lunar or Martian regolith, is presented. Process yields, and kinetics are used to verify the theoretical feasibility of applying four different microorganisms. Based on yields alone, three of the four organisms were not investigated further for use in biological ISRU. For the remaining organism, Shewanella oneidensis, the survivability impact of Martian regolith simulant JSC-MARS1 and Mars-abundant magnesium perchlorate were studied and found to be minimal. The payback time of the infrastructure installation needed for the process with S. oneidensis on Mars was analyzed and the sensitivity to various parameters was investigated. Water recycling efficiency and initial regolith concentration were found to be key to process performance. With a water recycling efficiency of 99.99% and initial regolith concentration of 300 g/L, leading to an iron concentration of approximately 44.7 g/L, a payback time of 3.3 years was found.
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- Westra, Edze R, et al.
(författare)
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H-NS-mediated repression of CRISPR-based immunity in Escherichia coli K12 can be relieved by the transcription activator LeuO
- 2010
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Ingår i: Molecular Microbiology. - : Wiley. - 0950-382X .- 1365-2958. ; 77:6, s. 1380-1393
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Tidskriftsartikel (refereegranskat)abstract
- The recently discovered prokaryotic CRISPR/Cas defence system provides immunity against viral infections and plasmid conjugation. It has been demonstrated that in Escherichia coli transcription of the Cascade genes (casABCDE) and to some extent the CRISPR array is repressed by heat-stable nucleoid-structuring (H-NS) protein, a global transcriptional repressor. Here we elaborate on the control of the E. coli CRISPR/Cas system, and study the effect on CRISPR-based anti-viral immunity. Transformation of wild-type E. coli K12 with CRISPR spacers that are complementary to phage Lambda does not lead to detectable protection against Lambda infection. However, when an H-NS mutant of E. coli K12 is transformed with the same anti-Lambda CRISPR, this does result in reduced sensitivity to phage infection. In addition, it is demonstrated that LeuO, a LysR-type transcription factor, binds to two sites flanking the casA promoter and the H-NS nucleation site, resulting in derepression of casABCDE12 transcription. Overexpression of LeuO in E. coli K12 containing an anti-Lambda CRISPR leads to an enhanced protection against phage infection. This study demonstrates that in E. coli H-NS and LeuO are antagonistic regulators of CRISPR-based immunity.
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