| 1. |
- Woitowich, N. C., et al.
(författare)
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Structural basis for light control of cell development revealed by crystal structures of a myxobacterial phytochrome
- 2018
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Ingår i: Iucrj. - : International Union of Crystallography (IUCr). - 2052-2525. ; 5:Part 5, s. 619-634
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Tidskriftsartikel (refereegranskat)abstract
- Phytochromes are red-light photoreceptors that were first characterized in plants, with homologs in photosynthetic and non-photosynthetic bacteria known as bacteriophytochromes (BphPs). Upon absorption of light, BphPs interconvert between two states denoted Pr and Pfr with distinct absorption spectra in the red and far-red. They have recently been engineered as enzymatic photoswitches for fluorescent-marker applications in non-invasive tissue imaging of mammals. This article presents cryo- and room-temperature crystal structures of the unusual phytochrome from the non-photosynthetic myxobacterium Stigmatella aurantiaca (SaBphP1) and reveals its role in the fruitingbody formation of this photomorphogenic bacterium. SaBphP1 lacks a conserved histidine (His) in the chromophore-binding domain that stabilizes the Pr state in the classical BphPs. Instead it contains a threonine (Thr), a feature that is restricted to several myxobacterial phytochromes and is not evolutionarily understood. SaBphP1 structures of the chromophore binding domain (CBD) and the complete photosensory core module (PCM) in wild-type and Thr-to-His mutant forms reveal details of the molecular mechanism of the Pr/Pfr transition associated with the physiological response of this myxobacterium to red light. Specifically, key structural differences in the CBD and PCM between the wild-type and the Thr-to-His mutant involve essential chromophore contacts with proximal amino acids, and point to how the photosignal is transduced through the rest of the protein, impacting the essential enzymatic activity in the photomorphogenic response of this myxobacterium.
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| 2. |
- Edlund, Petra, et al.
(författare)
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The room temperature crystal structure of a bacterial phytochrome determined by serial femtosecond crystallography
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Phytochromes are a family of photoreceptors that control light responses of plants, fungi and bacteria. A sequence of structural changes, which is not yet fully understood, leads to activation of an output domain. Time-resolved serial femtosecond crystallography (SFX) can potentially shine light on these conformational changes. Here we report the room temperature crystal structure of the chromophore-binding domains of the Deinococcus radiodurans phytochrome at 2.1 angstrom resolution. The structure was obtained by serial femtosecond X-ray crystallography from microcrystals at an X-ray free electron laser. We find overall good agreement compared to a crystal structure at 1.35 angstrom resolution derived from conventional crystallography at cryogenic temperatures, which we also report here. The thioether linkage between chromophore and protein is subject to positional ambiguity at the synchrotron, but is fully resolved with SFX. The study paves the way for time-resolved structural investigations of the phytochrome photocycle with time-resolved SFX.
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| 3. |
- Ragunathrao, Vijay Avin Balaji, et al.
(författare)
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Sphingosine-1-Phosphate Receptor 1 Activity Promotes Tumor Growth by Amplifying VEGF-VEGFR2 Angiogenic Signaling
- 2019
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Ingår i: Cell Reports. - : CELL PRESS. - 2211-1247. ; 29:11, s. 3472-3487
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Tidskriftsartikel (refereegranskat)abstract
- The vascular endothelial growth factor-A (VEGF-A)-VEGFR2 pathway drives tumor vascularization by activating proangiogenic signaling in endothelial cells (ECs). Here, we show that EC-sphingosine-1-phosphate receptor 1 (S1PR1) amplifies VEGFR2-mediated angiogenic signaling to enhance tumor growth. We show that cancer cells induce S1 PR1 activity in ECs, and thereby, conditional deletion of Si PR1 in ECs (EC-Slpr1(-/-) mice) impairs tumor vascularization and growth. Mechanistically, we show that S1 PR1 engages the heterotrimeric G-protein Gi, which amplifies VEGF-VEGFR2 signaling due to an increase in the activity of the tyrosine kinase c-Abl1. c-Abl1, by phosphorylating VEGFR2 at tyrosine-951, prolongs VEGFR2 retention on the plasmalemma to sustain Rac1 activity and EC migration. Thus, S1 PR1 or VEGFR2 antagonists, alone or in combination, reverse the tumor growth in control mice to the level seen in EC-Slpr1(-/-) mice. Our findings suggest that blocking S1 PR1 activity in ECs has the potential to suppress tumor growth by preventing amplification of VEGF-VEGFR2 signaling.
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| 4. |
- Bartenstein, J. E., et al.
(författare)
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Polymersomes at the solid-liquid interface : Dynamic morphological transformation and lubrication
- 2018
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Ingår i: Journal of Colloid and Interface Science. - : Academic Press. - 0021-9797 .- 1095-7103. ; 512, s. 260-271
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Tidskriftsartikel (refereegranskat)abstract
- Polymersomes are hollow spheres self-assembled from amphiphilic block copolymers of certain molecular architecture. Whilst they have been widely studied for biomedical applications, relatively few studies have reported their interfacial properties. In particular, lubrication by polymersomes has not been previously reported. Here, interfacial properties of polymersomes self-assembled from poly(butadiene)-poly(ethylene oxide) (PBD-PEO; molecular weight 10,400 g mol−1) have been studied at both hydrophilic and hydrophobic surfaces. Their morphology at silica and mica surfaces was imaged with quantitative nanomechanical property mapping atomic force microscopy (QNM AFM), and friction and surface forces they mediate under confinement between two surfaces were studied using colloidal probe AFM (CP-AFM). We find that the polymersomes remained intact but adopted flattened conformation once adsorbed to mica, with a relatively low coverage. However, on silica these polymersomes were unstable, rupturing to form donut shaped residues or patchy bilayers. On a silica surface hydrophobized with a 19 nm polystyrene (PS) film, the polymer vesicles formed a more stable layer with a higher surface coverage as compared to the hydrophilic surface, and the interfacial structure also evolved over time. Moreover, friction was greatly reduced on hydrophobized silica surfaces in the presence of polymersomes, suggesting their potential as effective aqueous lubricants.
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| 5. |
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| 6. |
- Elfwén, Ludvig, et al.
(författare)
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Coronary angiography in out-of-hospital cardiac arrest without ST elevation on ECG-Short- and long-term survival.
- 2018
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Ingår i: American Heart Journal. - : Elsevier BV. - 0002-8703 .- 1097-6744. ; 200, s. 90-95
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The potential benefit of early coronary angiography in out-of-hospital cardiac arrest (OHCA) patients without ST elevation on ECG is unclear. The aim of this study was to evaluate the association between early coronary angiography and survival in these patients.METHODS: Nationwide observational study between 2008 and 2013. Included were patients admitted to hospital after witnessed OHCA, with shockable rhythm, age 18 to 80 years and unconscious. Patients with ST-elevation on ECG were excluded. Patients that underwent early CAG (within 24 hours) were compared with no early CAG (later during the hospital stay or not at all). Outcomes were survival at 30 days, 1 year, and 3 years. Multivariate analysis included pre-hospital factors, comorbidity and ECG-findings.RESULTS: In total, 799 OHCA patients fulfilled the inclusion criteria, of which 275 (34%) received early CAG versus 524 (66%) with no early CAG. In the early CAG group, the proportion of patients with an occluded coronary artery was 27% and 70% had at least one significant coronary stenosis (defined as narrowing of coronary lumen diameter of ≥50%). The 30-day survival rate was 65% in early CAG group versus 52% with no early CAG (P < .001). The adjusted OR was 1.42 (95% CI 1.00-2.02). The one-year survival rate was 62% in the early CAG group versus 48% in the no early CAG group with the adjusted hazard ratio of 1.35 (95% CI 1.04-1.77).CONCLUSION: In this population of bystander-witnessed cases of out-of-hospital cardiac arrest with shockable rhythm and ECG without ST elevation, early coronary angiography may be associated with improved short and long term survival.
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| 7. |
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| 8. |
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| 9. |
- Ghaffarpour, Nader, et al.
(författare)
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Long-term health-related quality of life in children with lymphatic malformations treated with sclerotherapy generally matched age-appropriate standardised population norms
- 2019
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Ingår i: Acta Paediatrica. - : Wiley. - 0803-5253 .- 1651-2227. ; 108:8, s. 1499-1506
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Tidskriftsartikel (refereegranskat)abstract
- Aim: We assessed the long-term health-related quality of life (HRQoL) of children who received sclerotherapy for lymphatic malformations. This treatment involved injecting drugs into the blood vessels to make them shrink.Methods: Our cross-sectional study retrospectively reviewed patients who received OK-432 sclerotherapy injections at Karolinska University Hospital, Stockholm, Sweden, from 1998 to 2013. We studied 49 patients (63% female) aged 8-18 at least five years after their first injection. HRQoL was assessed with the KIDSCREEN-52 questionnaire and a study-specific questionnaire addressed disease consequences and patient satisfaction. We determined associations between HRQoL and disease and treatment and the patient's sex.Results: Overall HRQoL paralleled age-appropriate norms in the general population, but some subgroups had lower levels. Regression-based estimates showed that larger numbers of injections were negatively associated with HRQoL in the dimensions autonomy, parent relations and home life, financial resources and school environment (p = 0.01-0.03). Malformations in the head and neck area were negative predictors across dimensions and were strongest for psychological well-being (p = 0.009), parent relations and home life (p = 0.017) and school environment (p = 0.006).Conclusion: Despite generally positive outcomes, multiple injections and malformations in the head and neck were associated with impaired HRQoL.
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| 10. |
- Ghaffarpour, N, et al.
(författare)
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Patients with lymphatic malformations who receive the immunostimulant OK-432 experience excellent long-term outcomes
- 2015
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Ingår i: Acta Paediatrica. - : Wiley. - 0803-5253 .- 1651-2227. ; 104:11, s. 1169-73
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Tidskriftsartikel (refereegranskat)abstract
- AIM: Sclerotherapy is the primary treatment for lymphatic malformations. The aim of this study was to evaluate the long-term outcome in patients with lymphatic malformations treated with the immunostimulant OK-432 as a sclerosant.METHODS: Between 1998 and 2013, we enrolled 131 of 138 eligible patients treated with OK-432 for lymphatic malformations in a retrospective study. The malformations were categorised according to the International Society for the Study of Vascular Anomalies. The outcome was assessed with a clinical examination and a questionnaire.RESULTS: The lymphatic malformations were localised to the head/neck (60%), the trunk (20%) and the extremities (6%) or involved with more than one region (14%). Patients with microcystic (10%), macrocystic (21%) and mixed lymphatic malformations (69%) underwent a median number of three, two and two injection treatments, respectively. The median age at the first injection was 3.4 years. Good or excellent clinical outcomes were seen in 70% of the patients. The number of injections, previous treatment and lesion localisation, but not time to follow-up and cyst size, predicted the clinical outcome.CONCLUSION: OK-432 treatment resulted in a successful outcome in 70% of patients with lymphatic malformations. The long-term outcome was comparable to the short-term outcome.
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| 11. |
- Hwang, K. -H, et al.
(författare)
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Growth of self-template 3D gold nanoparticles on boron nanowire arrays for surface plasmon resonance biosensor application
- 2018
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Ingår i: Encyclopedia of Interfacial Chemistry: Surface Science and Electrochemistry. - : Elsevier. - 9780128098943 - 9780128097397 ; , s. 460-464
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Enabling detection of target molecules at low concentration is a key feature in localized surface plasmon resonance (LSPR) biosensors, which utilizes the remarkable optical properties of metal nanoparticles such as gold (Au) and silver (Ag) induced by the excitation of LSPR. However, the clear interrelationship between three-dimensional (3D) metal nanoparticle topography and localization of SPR is not fully understood. For the studies, we here propose and demonstrate an approach for fabricating new type of self-template 3D Au nanostructures by using boron nanowire arrays (BNWs) as a building block grown by oxide-assisted vapor-liquid-solid (VLS) mode at relatively low temperatures. This is the first report on formation of 3D Au pores and clusters induced by boron oxide (B2O3) below 500°C.
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| 12. |
- Ljungstrom, L., et al.
(författare)
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Clinical evaluation of commercial nucleic acid amplification tests in patients with suspected sepsis
- 2015
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Ingår i: Bmc Infectious Diseases. - : Springer Science and Business Media LLC. - 1471-2334. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Background: Sepsis is a serious medical condition requiring timely administered, appropriate antibiotic therapy. Blood culture is regarded as the gold standard for aetiological diagnosis of sepsis, but it suffers from low sensitivity and long turnaround time. Thus, nucleic acid amplification tests (NAATs) have emerged to shorten the time to identification of causative microbes. The aim of the present study was to evaluate the clinical utility in everyday practice in the emergency department of two commercial NAATs in patients suspected with sepsis. Methods: During a six-week period, blood samples were collected consecutively from all adult patients admitted to the general emergency department for suspicion of a community-onset sepsis and treated with intravenous antibiotics. Along with conventional blood cultures, multiplex PCR (Magicplex (TM)) was performed on whole blood specimens whereas portions from blood culture bottles were used for analysis by microarray-based assay (Prove-it (TM)). The aetiological significance of identified organisms was determined by two infectious disease physicians based on clinical presentation and expected pathogenicity. Results: Among 382 episodes of suspected sepsis, clinically relevant microbes were detected by blood culture in 42 episodes (11%), by multiplex PCR in 37 episodes (9.7%), and by microarray in 32 episodes (8.4%). Although moderate agreement with blood culture (kappa 0.50), the multiplex PCR added diagnostic value by timely detection of 15 clinically relevant findings in blood culture-negative specimens. Results of the microarray corresponded very well to those of blood culture (kappa 0.90), but were available just marginally prior to blood culture results. Conclusions: The use of NAATs on whole blood specimens in adjunct to current culture-based methods provides a clinical add-on value by allowing for detection of organisms missed by blood culture. However, the aetiological significance of findings detected by NAATs should be interpreted with caution as the high analytical sensitivity may add findings that do not necessarily corroborate with the clinical diagnosis.
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| 13. |
- Llona-Minguez, Sabin, et al.
(författare)
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Discovery of the First Potent and Selective Inhibitors of Human dCTP Pyrophosphatase 1
- 2016
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Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 59:3, s. 1140-1148
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Tidskriftsartikel (refereegranskat)abstract
- The dCTPase pyrophosphatase 1 (dCTPase) regulates the intracellular nucleotide pool through hydrolytic degradation of canonical and noncanonical nucleotide triphosphates (dNTPs). dCTPase is highly expressed in multiple carcinomas and is associated with cancer cell sternness. Here we report on the development of the first potent and selective dCTPase inhibitors that enhance the cytotoxic effect of cytidine analogues in leukemia cells. Boronate 30 displays a promising in vitro ADME profile, including plasma and mouse microsomal half-lives, aqueous solubility, cell permeability and CYP inhibition, deeming it a suitable compound for in vivo studies.
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| 14. |
- Ringh, M, et al.
(författare)
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The challenges and possibilities of public access defibrillation.
- 2018
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Ingår i: Journal of Internal Medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 283:3, s. 238-256
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Tidskriftsartikel (refereegranskat)abstract
- Out-of-hospital cardiac arrest (OHCA) is a major health problem that affects approximately four hundred and thousand patients annually in the United States alone. It is a major challenge for the emergency medical system as decreased survival rates are directly proportional to the time delay from collapse to defibrillation. Historically, defibrillation has only been performed by physicians and in-hospital. With the development of automated external defibrillators (AEDs), rapid defibrillation by nonmedical professionals and subsequently by trained or untrained lay bystanders has become possible. Much hope has been put to the concept of Public Access Defibrillation with a massive dissemination of public available AEDs throughout most Western countries. Accordingly, current guidelines recommend that AEDs should be deployed in places with a high likelihood of OHCA. Despite these efforts, AED use is in most settings anecdotal with little effect on overall OHCA survival. The major reasons for low use of public AEDs are that most OHCAs take place outside high incidence sites of cardiac arrest and that most OHCAs take place in residential settings, currently defined as not suitable for Public Access Defibrillation. However, the use of new technology for identification and recruitment of lay bystanders and nearby AEDs to the scene of the cardiac arrest as well as new methods for strategic AED placement redefines and challenges the current concept and definitions of Public Access Defibrillation. Existing evidence of Public Access Defibrillation and knowledge gaps and future directions to improve outcomes for OHCA are discussed. In addition, a new definition of the different levels of Public Access Defibrillation is offered as well as new strategies for increasing AED use in the society.
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| 15. |
- Sanchez, J. C., et al.
(författare)
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High-resolution crystal structures of amyxobacterial phytochrome at cryo and roomtemperatures
- 2019
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Ingår i: Structural Dynamics-Us. - : AIP Publishing. - 2329-7778. ; 6:5
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Tidskriftsartikel (refereegranskat)abstract
- Phytochromes (PHYs) are photoreceptor proteins first discovered in plants, where they control a variety of photomorphogenesis events. PHYs as photochromic proteins can reversibly switch between two distinct states: a red light (Pr) and a far-red light (Pfr) absorbing form. The discovery of Bacteriophytochromes (BphPs) in nonphotosynthetic bacteria has opened new frontiers in our understanding of the mechanisms by which these natural photoswitches can control single cell development, although the role of BphPs in vivo remains largely unknown. BphPs are dimeric proteins that consist of a photosensory core module (PCM) and an enzymatic domain, often a histidine kinase. The PCM is composed of three domains (PAS, GAF, and PHY). It holds a covalently bound open-chain tetrapyrrole (biliverdin, BV) chromophore. Upon absorption of light, the double bond between BV rings C and D isomerizes and reversibly switches the protein between Pr and Pfr states. We report crystal structures of the wild-type and mutant (His275Thr) forms of the canonical BphP from the nonphotosynthetic myxobacterium Stigmatella aurantiaca (SaBphP2) in the Pr state. Structures were determined at 1.65A degrees and 2.2A degrees (respectively), the highest resolution of any PCM construct to date. We also report the room temperature wild-type structure of the same protein determined at 2.1A degrees at the SPring-8 Angstrom Compact free electron LAser (SACLA), Japan. Our results not only highlight and confirm important amino acids near the chromophore that play a role in Pr-Pfr photoconversion but also describe the signal transduction into the PHY domain which moves across tens of angstroms after the light stimulus. (C) 2019 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
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| 16. |
- Zijlstra, Jolande A, et al.
(författare)
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Different defibrillation strategies in survivors after out-of-hospital cardiac arrest.
- 2018
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Ingår i: Heart. - : BMJ. - 1355-6037 .- 1468-201X. ; 104:23, s. 1929-1936
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: In the last decade, there has been a rapid increase in the dissemination of automated external defibrillators (AEDs) for prehospital defibrillation of out-of-hospital cardiac arrest patients. The aim of this study was to study the association between different defibrillation strategies on survival rates over time in Copenhagen, Stockholm, Western Sweden and Amsterdam, and the hypothesis was that non-EMS defibrillation increased over time and was associated with increased survival.METHODS: We performed a retrospective analysis of four prospectively collected cohorts of out-of-hospital cardiac arrest patients between 2008 and 2013. Emergency medical service (EMS)-witnessed arrests were excluded.RESULTS: A total of 22 453 out-of-hospital cardiac arrest patients with known survival status were identified, of whom 2957 (13%) survived at least 30 days postresuscitation. Of all survivors with a known defibrillation status, 2289 (81%) were defibrillated, 1349 (59%) were defibrillated by EMS, 454 (20%) were defibrillated by a first responder AED and 429 (19%) were defibrillated by an onsite AED and 57 (2%) were unknown. The percentage of survivors defibrillated by first responder AEDs (from 13% in 2008 to 26% in 2013, p<0.001 for trend) and onsite AEDs (from 14% in 2008 to 30% in 2013, p<0.001 for trend) increased. The increased use of these non-EMS AEDs was associated with the increase in survival rate of patients with a shockable initial rhythm.CONCLUSION: Survivors of out-of-hospital cardiac arrest are increasingly defibrillated by non-EMS AEDs. This increase is primarily due to a large increase in the use of onsite AEDs as well as an increase in first-responder defibrillation over time. Non-EMS defibrillation accounted for at least part of the increase in survival rate of patients with a shockable initial rhythm.
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