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Sökning: WFRF:(Krishnamurthy V)

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1.
  • Abadie, J., et al. (författare)
  • Search for Gravitational Waves Associated with Gamma-Ray Bursts during LIGO Science Run 6 and Virgo Science Runs 2 and 3
  • 2012
  • Ingår i: Astrophysical Journal. - 0004-637X. ; 760:1
  • Tidskriftsartikel (refereegranskat)abstract
    • We present the results of a search for gravitational waves associated with 154 gamma-ray bursts (GRBs) that were detected by satellite-based gamma-ray experiments in 2009-2010, during the sixth LIGO science run and the second and third Virgo science runs. We perform two distinct searches: a modeled search for coalescences of either two neutron stars or a neutron star and black hole, and a search for generic, unmodeled gravitational-wave bursts. We find no evidence for gravitational-wave counterparts, either with any individual GRB in this sample or with the population as a whole. For all GRBs we place lower bounds on the distance to the progenitor, under the optimistic assumption of a gravitational-wave emission energy of 10(-2) M-circle dot c(2) at 150 Hz, with a median limit of 17 Mpc. For short-hard GRBs we place exclusion distances on binary neutron star and neutron-star-black-hole progenitors, using astrophysically motivated priors on the source parameters, with median values of 16 Mpc and 28 Mpc, respectively. These distance limits, while significantly larger than for a search that is not aided by GRB satellite observations, are not large enough to expect a coincidence with a GRB. However, projecting these exclusions to the sensitivities of Advanced LIGO and Virgo, which should begin operation in 2015, we find that the detection of gravitational waves associated with GRBs will become quite possible.
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  • Abadie, J., et al. (författare)
  • Implementation and testing of the first prompt search for gravitational wave transients with electromagnetic counterparts
  • 2012
  • Ingår i: Astronomy & Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 539
  • Tidskriftsartikel (refereegranskat)abstract
    • Aims. A transient astrophysical event observed in both gravitational wave (GW) and electromagnetic (EM) channels would yield rich scientific rewards. A first program initiating EM follow-ups to possible transient GW events has been developed and exercised by the LIGO and Virgo community in association with several partners. In this paper, we describe and evaluate the methods used to promptly identify and localize GW event candidates and to request images of targeted sky locations. Methods. During two observing periods (Dec. 17, 2009 to Jan. 8, 2010 and Sep. 2 to Oct. 20, 2010), a low-latency analysis pipeline was used to identify GW event candidates and to reconstruct maps of possible sky locations. A catalog of nearby galaxies and Milky Way globular clusters was used to select the most promising sky positions to be imaged, and this directional information was delivered to EM observatories with time lags of about thirty minutes. A Monte Carlo simulation has been used to evaluate the low-latency GW pipeline's ability to reconstruct source positions correctly. Results. For signals near the detection threshold, our low-latency algorithms often localized simulated GW burst signals to tens of square degrees, while neutron star/neutron star inspirals and neutron star/black hole inspirals were localized to a few hundred square degrees. Localization precision improves for moderately stronger signals. The correct sky location of signals well above threshold and originating from nearby galaxies may be observed with similar to 50% or better probability with a few pointings of wide-field telescopes.
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  • Abadie, J., et al. (författare)
  • All-sky search for gravitational-wave bursts in the second joint LIGO-Virgo run
  • 2012
  • Ingår i: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 85:12
  • Tidskriftsartikel (refereegranskat)abstract
    • We present results from a search for gravitational-wave bursts in the data collected by the LIGO and Virgo detectors between July 7, 2009 and October 20, 2010: data are analyzed when at least two of the three LIGO-Virgo detectors are in coincident operation, with a total observation time of 207 days. The analysis searches for transients of duration less than or similar to 1 s over the frequency band 64-5000 Hz, without other assumptions on the signal waveform, polarization, direction or occurrence time. All identified events are consistent with the expected accidental background. We set frequentist upper limits on the rate of gravitational-wave bursts by combining this search with the previous LIGO-Virgo search on the data collected between November 2005 and October 2007. The upper limit on the rate of strong gravitational-wave bursts at the Earth is 1.3 events per year at 90% confidence. We also present upper limits on source rate density per year and Mpc(3) for sample populations of standard-candle sources. As in the previous joint run, typical sensitivities of the search in terms of the root-sum-squared strain amplitude for these waveforms lie in the range similar to 5 x 10(-22) Hz(-1/2) to similar to 1 x 10(-20) Hz(-1/2). The combination of the two joint runs entails the most sensitive all-sky search for generic gravitational-wave bursts and synthesizes the results achieved by the initial generation of interferometric detectors.
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  • Abadie, J., et al. (författare)
  • All-sky search for periodic gravitational waves in the full S5 LIGO data
  • 2012
  • Ingår i: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 85:2
  • Tidskriftsartikel (refereegranskat)abstract
    • We report on an all-sky search for periodic gravitational waves in the frequency band 50-800 Hz and with the frequency time derivative in the range of 0 through -6 x 10(-9) Hz/s. Such a signal could be produced by a nearby spinning and slightly nonaxisymmetric isolated neutron star in our Galaxy. After recent improvements in the search program that yielded a 10x increase in computational efficiency, we have searched in two years of data collected during LIGO's fifth science run and have obtained the most sensitive all-sky upper limits on gravitational-wave strain to date. Near 150 Hz our upper limit on worst-case linearly polarized strain amplitude h(0) is 1 x 10(-24), while at the high end of our frequency range we achieve a worst-case upper limit of 3.8 x 10(-24) for all polarizations and sky locations. These results constitute a factor of 2 improvement upon previously published data. A new detection pipeline utilizing a loosely coherent algorithm was able to follow up weaker outliers, increasing the volume of space where signals can be detected by a factor of 10, but has not revealed any gravitational-wave signals. The pipeline has been tested for robustness with respect to deviations from the model of an isolated neutron star, such as caused by a low-mass or long-period binary companion.
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  • Abadie, J., et al. (författare)
  • First low-latency LIGO plus Virgo search for binary inspirals and their electromagnetic counterparts
  • 2012
  • Ingår i: Astronomy & Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 541
  • Tidskriftsartikel (refereegranskat)abstract
    • Aims. The detection and measurement of gravitational-waves from coalescing neutron-star binary systems is an important science goal for ground-based gravitational-wave detectors. In addition to emitting gravitational-waves at frequencies that span the most sensitive bands of the LIGO and Virgo detectors, these sources are also amongst the most likely to produce an electromagnetic counterpart to the gravitational-wave emission. A joint detection of the gravitational-wave and electromagnetic signals would provide a powerful new probe for astronomy. Methods. During the period between September 19 and October 20, 2010, the first low-latency search for gravitational-waves from binary inspirals in LIGO and Virgo data was conducted. The resulting triggers were sent to electromagnetic observatories for followup. We describe the generation and processing of the low-latency gravitational-wave triggers. The results of the electromagnetic image analysis will be described elsewhere. Results. Over the course of the science run, three gravitational-wave triggers passed all of the low-latency selection cuts. Of these, one was followed up by several of our observational partners. Analysis of the gravitational-wave data leads to an estimated false alarm rate of once every 6.4 days, falling far short of the requirement for a detection based solely on gravitational-wave data.
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  • Abadie, J., et al. (författare)
  • Search for gravitational waves from intermediate mass binary black holes
  • 2012
  • Ingår i: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 85:10
  • Tidskriftsartikel (refereegranskat)abstract
    • We present the results of a weakly modeled burst search for gravitational waves from mergers of nonspinning intermediate mass black holes in the total mass range 100-450 M-circle dot and with the component mass ratios between 1: and 4:1. The search was conducted on data collected by the LIGO and Virgo detectors between November of 2005 and October of 2007. No plausible signals were observed by the search which constrains the astrophysical rates of the intermediate mass black holes mergers as a function of the component masses. In the most efficiently detected bin centered on 88 + 88 M-circle dot, for nonspinning sources, the rate density upper limit is 0.13 per Mpc(3) per Myr at the 90% confidence level.
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  • Abadie, J., et al. (författare)
  • Search for gravitational waves from low mass compact binary coalescence in LIGO's sixth science run and Virgo's science runs 2 and 3
  • 2012
  • Ingår i: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 85:8
  • Tidskriftsartikel (refereegranskat)abstract
    • We report on a search for gravitational waves from coalescing compact binaries using LIGO and Virgo observations between July 7, 2009, and October 20, 2010. We searched for signals from binaries with total mass between 2 and 25M(circle dot); this includes binary neutron stars, binary black holes, and binaries consisting of a black hole and neutron star. The detectors were sensitive to systems up to 40 Mpc distant for binary neutron stars, and further for higher mass systems. No gravitational-wave signals were detected. We report upper limits on the rate of compact binary coalescence as a function of total mass, including the results from previous LIGO and Virgo observations. The cumulative 90% confidence rate upper limits of the binary coalescence of binary neutron star, neutron star-black hole, and binary black hole systems are 1.3 x 10(-4), 3.1 x 10(-5), and 6.4 x 10(-6) Mpc(-3) yr(-1), respectively. These upper limits are up to a factor 1.4 lower than previously derived limits. We also report on results from a blind injection challenge.
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  • Abadie, J., et al. (författare)
  • Upper limits on a stochastic gravitational-wave background using LIGO and Virgo interferometers at 600-1000 Hz
  • 2012
  • Ingår i: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 85:12
  • Tidskriftsartikel (refereegranskat)abstract
    • A stochastic background of gravitational waves is expected to arise from a superposition of many incoherent sources of gravitational waves, of either cosmological or astrophysical origin. This background is a target for the current generation of ground-based detectors. In this article we present the first joint search for a stochastic background using data from the LIGO and Virgo interferometers. In a frequency band of 600-1000 Hz, we obtained a 95% upper limit on the amplitude of Omega(GW)(f) = Omega(3)(f/900 Hz)(3), of Omega(3) < 0.32, assuming a value of the Hubble parameter of h(100) = 0.71. These new limits are a factor of seven better than the previous best in this frequency band.
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  • Campbell, PJ, et al. (författare)
  • Pan-cancer analysis of whole genomes
  • 2020
  • Ingår i: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 578:7793, s. 82-
  • Tidskriftsartikel (refereegranskat)abstract
    • Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale1–3. Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4–5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter4; identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation5,6; analyses timings and patterns of tumour evolution7; describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity8,9; and evaluates a range of more-specialized features of cancer genomes8,10–18.
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  • Sakuraba, K, et al. (författare)
  • METABOLIC CHANGES INDUCED BY ANTI-MALONDIALDEHYDE/MALINDIALDEHYDE-ACETALDEHYDE ANTIBODIES PROMOTE OSTEOCLAST DEVELOPMENT
  • 2020
  • Ingår i: ANNALS OF THE RHEUMATIC DISEASES. - : BMJ. - 0003-4967 .- 1468-2060. ; 79, s. 934-935
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • Malondialdehyde (MDA) is a highly reactive compound produced by lipid-peroxidation in situations associated with oxidative stress. MDA can irreversibly modify proteins residues such as lysine, arginine and histidine. In addition, MDA adducts can further react with acetaldehyde to generate malondialdehyde-acetaldehyde (MAA) modifications. Such modifications can give rise to immunogenic neo-epitopes that are recognized by autoantibodies. In fact, anti-MDA/MAA IgG antibodies are significantly increased in the serum of patients with autoimmune diseases, such as rheumatoid arthritis (RA) (1) and systemic lupus erythematosus (2). Recently, we have shown that anti-MDA/MAA IgG antibodies are able to promote osteoclast (OC) differentiationin vitro(1).Objectives:To investigate the molecular mechanisms triggered by anti-MDA/MAA autoantibodies during osteoclastogenesis.Methods:OCs were generated from monocyte-derived macrophages in the presence of the cytokines RANK-L and M-CSF. The development of OCs was monitored by light microscopy following tartrate-resistant acid phosphatase (TRAP) staining and erosion area on synthetic calcium phosphate-coated plates. Three different recombinant human monoclonal anti-MDA/MAA antibodies, cloned from single synovial B cells of RA patients, control antibodies and Fab fragments of the antibodies were added to OC cultures. Glycolysis was inhibited by 2-deoxyglucose, and Fc-gamma receptor I or II by anti-CD64 or anti-CD16 neutralizing antibodies. IL-8 levels were measured by enzyme linked immunosorbent assay. Cellular metabolism was monitored using Seahorse XF Analyzer (extracellular acidification rate and oxygen consumption) and a colorimetric L-Lactate assay.Results:Lactic acid production correlated with the osteoclastogenetic effect of some but not all anti-MDA/MAA antibodies on OCs (R=0.4758, p=0.0252) suggesting an antibody-mediated regulation of glycolysis. Further, extracellular acidification (ECAR) and oxygen consumption (OCR) rate of the developing OCs were increased by the osteoclastogenic anti-MDA/MAA clones (maximum increase of 54% for the ECAR and 78% for the OCR by clone 146+:01G07, and maximum increase of 28% for the ECAR and 39% for the OCR by clone 1103:01H05), but not by the non-osteoclastogenetic anti-MDA/MAA clones or control antibodies. The glycolysis inhibitor 2-deoxyglucose completely abolished the osteoclastogenetic effect of the anti-MDA/MAA clones at drug concentrations that did not influenced baseline OC development. Fab2 fragments of the osteocalstogenetic anti-MDA/MAA clones had no effect on OC development and metabolism. In accordance with this, Fc-gamma receptor I neutralizing antibodies completely abolished the osteocalstogenetic effect of the anti-MDA/MAA clones. The osteoclastogenetic effect of the anti-MDA/MAA antibodies was independent of IL-8 production. In contrast to anti MDA/MAA antibodies, ACPA-mediated osteoclastogenesis was independent of glycolysis and Fc-gamma receptors but dependent on IL-8.Conclusion:Our results describe a novel glycolysis-dependent mechanism by which anti-MDA/MAA antibodies promote osteoclast development that is different from the one previously described for ACPA.References:[1] C. Grönwall et al. Journal of Autoimmunity 84 (2017) 29-45.[2] C. Wang et al. Arthritis and Rheumatism 62 (2010) 2064-2072Disclosure of Interests:Koji Sakuraba: None declared, Akilan Krishnamurthy: None declared, Alexandra Circiumaru: None declared, Meng Sun: None declared, Vijay Joshua: None declared, Marianne Engström: None declared, Xiaowei Zheng: None declared, Cheng Xu: None declared, Khaled Amara: None declared, Vivianne Malmström Grant/research support from: VM has had research grants from Janssen Pharmaceutica, Sergiu-Bogdan Catrina: None declared, Caroline Grönwall: None declared, Bence Réthi: None declared, Anca Catrina: None declared
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  • Sakuraba, K, et al. (författare)
  • METABOLIC CHANGES INDUCED BY ANTI-MALONDIALDEHYDE/MALINDIALDEHYDE- ACETALDEHYDE ANTIBODIES PROMOTE OSTEOCLAST DEVELOPMENT
  • 2021
  • Ingår i: ANNALS OF THE RHEUMATIC DISEASES. - : BMJ. - 0003-4967 .- 1468-2060. ; 80, s. 429-429
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • Malondialdehyde (MDA) is a highly reactive compound generated during lipid-peroxidation in conditions associated with oxidative stress. MDA can irreversibly modify proteins (e.g. lysine, arginine and histidine residues). In addition, acetaldehyde can further react with MDA adducts to form malondialdehyde-acetaldehyde (MAA) modification. Such protein modifications can lead to immunogenic neo-epitopes that are recognized by autoantibodies. In fact, anti-MDA/MAA IgG antibodies are significantly increased in the serum of patients with autoimmune diseases, such as rheumatoid arthritis (RA) (1). Interestingly, anti-MDA/MAA antibodies have been shown to promote osteoclast (OC) differentiation in vitro suggesting a potential role for these autoantibodies in bone damage associated with RA (1).Objectives:Little is known about the molecular mechanisms activated by autoantibodies in RA. Here, we elucidate the pathways specifically triggered by anti-MDA/MAA autoantibodies in developing osteoclasts.Methods:Recombinant human monoclonal anti-MDA/MAA antibodies, which were previously cloned from single synovial B cells of RA patients, were added to different OC assays. OCs were generated from monocyte-derived macrophages in the presence of the cytokines RANK-L and M-CSF. OC development was monitored by light microscopy following tartrate-resistant acid phosphatase staining and by erosion assays using calcium phosphate-coated plates. Bone morphometrics were studied in anti-MDA/MAA-injected mice using X-ray microscopy. Cellular metabolism was analyzed by mass spectrometry, Seahorse XF Analyzer and a colorimetric L-Lactate assay.Results:Anti-MDA/MAA antibodies induced a robust OC differentiation in vitro and bone loss in vivo. The anti-MDA/MAA antibodies acted on developing OCs by increasing glycolysis via an Fcγ receptor I-mediated pathway and the upregulation of the transcription factors HIF-1α, Myc and CHREBP. Such regulation of cellular metabolism was exclusively observed in the presence of the osteoclastogenic anti-MDA/MAA clones, whereas other RA-associated autoantibodies (anti-MDA/MAA or anti-citrullinated protein antibodies) had no effect on metabolism. The anti-MDA/MAA treatment induced a shift in the tricarboxylic acid (TCA) cycle activity in developing OCs, leading to the accumulation of citrate and aconitate.Conclusion:We described a novel type of autoantibody-induced pathway in RA, which might contribute to increased OC activation and a consequent bone loss. Anti-MDA/MAA antibodies promoted osteoclast development by increasing glycolysis and by modulating the TCA cycle through a signaling pathway that included Fcγ receptor I and a network of transcription factors acting on glycolysis. A TCA cycle bias towards citrate production suggests that the anti-MDA/MAA antibodies might stimulate OCs via increasing lipid biosynthesis in the cells.References:[1]Grönwall C. et al. J. Autoimmunity 84 (2017): 29-45.Acknowledgements:This Project has received funding from FOREUM, Foundation for Research in Rheumatology, from the European Research Council (ERC) grant agreement CoG 2017 - 7722209_PREVENT RA, the EU/EFPIA Innovative Medicine Initiative grant agreement 777357_RTCure, the Konung Gustaf V:s och Drottning Victorias Frimurarestiftelse and Knut and Alice Wallenberg Foundation.Disclosure of Interests:Koji Sakuraba: None declared, Akilan Krishnamurthy: None declared, Alexandra Circiumaru: None declared, Vijay Joshua: None declared, Heidi Wähämaa: None declared, Marianne Engström: None declared, Meng Sun: None declared, Xiaowei Zheng: None declared, Cheng Xu: None declared, Khaled Amara: None declared, Vivianne Malmström Grant/research support from: collaboration with Pfizer, unrelated to the abstract, Sergiu-Bogdan Catrina: None declared, Caroline Grönwall: None declared, Bence Réthi: None declared, Anca Catrina Grant/research support from: collaboration with BMS and Pfizer, unrelated to the present abstract
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  • Sun, M, et al. (författare)
  • Anticitrullinated protein antibodies facilitate migration of synovial tissue-derived fibroblasts
  • 2019
  • Ingår i: Annals of the rheumatic diseases. - : BMJ. - 1468-2060 .- 0003-4967. ; 78:12, s. 1621-1631
  • Tidskriftsartikel (refereegranskat)abstract
    • Rheumatoid arthritis (RA)-specific anti-citrullinated protein/peptide antibodies (ACPAs) might contribute to bone loss and arthralgia before the onset of joint inflammation. We aimed to dissect additional mechanisms by which ACPAs might contribute to development of joint pathology.MethodsFibroblast-like synoviocytes (FLS) were isolated from the synovial membrane of patients with RA. The FLS cultures were stimulated with polyclonal ACPAs (anti-CCP-2 antibodies) purified from the peripheral blood of patients with RA or with monoclonal ACPAs derived from single synovial fluid B cells. We analysed how ACPAs modulate FLS by measuring cell adhesion and mobility as well as cytokine production. Expression of protein arginine deiminase (PAD) enzymes and protein citrullination were analysed by immunofluorescence, and signal transduction was studied using immunoblotting.ResultsChallenge of FLS by starvation-induced stress or by exposure to the chemokine interleukin-8 was essential to sensitise the cells to ACPAs. These challenges led to an increased PAD expression and protein citrullination and an ACPA-mediated induction of FLS migration through a mechanism involving phosphoinositide 3-kinase activation. Inhibition of the PAD enzymes or competition with soluble citrullinated proteins or peptides completely abolished the ACPA-induced FLS migration. Different monoclonal ACPAs triggered distinct cellular effects in either fibroblasts or osteoclasts, suggesting unique roles for individual ACPA clones in disease pathogenesis.ConclusionWe propose that transient synovial insults in the presence of a certain pre-existing ACPA repertoire might result in an ACPA-mediated increase of FLS migration.
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  • Sun, M, et al. (författare)
  • DIVERSITY OF ANTI-CITRULLINATED PROTEIN ANTIBODY COMPOSITIONS INFLUENCE SYNOVIAL FIBROBLAST REACTIVITY
  • 2020
  • Ingår i: ANNALS OF THE RHEUMATIC DISEASES. - : BMJ. - 0003-4967 .- 1468-2060. ; 79, s. 569-570
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • Anti-citrullinated protein antibodies (ACPAs) play an important role in rheumatoid arthritis (RA) pathogenesis. We hypothesized that the effect of these antibodies is mediated by their binding to synovial fibroblasts and inducing an increased mobility of fibroblasts1.Objectives:In our study, we analyzed and compared fibroblast modulation by ACPA pools obtained from different patients or by a set of monoclonal ACPAs with different fine specificity that were obtained from different tissue sites.Methods:Synovial fibroblasts were isolated from RA patients synovial tissue biopsies. Individual polyclonal ACPA and control IgGs were purified from sera of four ACPA-positive RA patients by affinity purification on protein G and CCP-2 columns. Monoclonal antibodies were derived from memory B cell isolated from blood2, synovial fluid or bronchoalveolar lavage of RA patients. Whole antibodies and F(ab’)2 fragments were tested in fibroblast migration using IncuCyte live-cell analysis. Blocking experiments were performed with soluble citrullinated proteins in SF migration. Cross-reactivity of the antibodies to citrullinated and acetylated epitopes was tested using PAD inhibitors (Cl-amidine and GSK199), histone acetyltransferases (anacardic acid) and deacetylases (trichostatin A). Binding patterns of monoclonal ACPAs, both whole and F(ab’)2 fragments were analyzed in synovial biopsies obtained from both healthy donors and RA patients.Results:Three out of four tested individual ACPA were able to promote fibroblast migration. Five out of nine tested monoclonal ACPAs stimulated fibroblast migration. One of these antibodies, clone 1325:01B09 is characterized by cross-reactivity to citrullinated, homocitrullinated and acetylated targets. The effect of 1325:01B09 on fibroblast migration was completely abolished by Cl-amidine or by pre-incubating the antibody with citrullinated fibrinogen or histone but not citrullinated enolase or vimentin. Despite the cross-reactivity to acetylated epitopes, neither anacardic acid nor trichostatin A could modulate the 1325:01B09 effect on fibroblast migration. F(ab’)2 fragments of this antibody stimulated fibroblast migration and labelled podoplanin-positive fibroblasts in inflamed RA synovium similarly to the intact antibody, indicating an Fc-independent effect.Conclusion:The effect on fibroblast mobility was likely to be mediated by binding to citrullinated epitopes but not through Fc receptors. Detection of fibroblast modulating ACPAs in majority of RA patients indicated that fibroblasts might be key cellular targets in disease pathogenesis, although individual variability might exist in the composition of ACPA cellular targets.References:[1]Sun M, Rethi B, Krishnamurthy A, et al. Anticitrullinated protein antibodies facilitate migration of synovial tissue-derived fibroblasts. Ann Rheum Dis 2019;78(12):1621-31. doi: 10.1136/annrheumdis-2018-214967 [published Online First: 2019/09/05][2]Amara K, Lena Israelsson, Ragnhild Stålesen, et al. A Refined Protocol for Identifying Citrulline-specific Monoclonal Antibodies from Single Human B Cells from Rheumatoid Arthritis Patient Material. Bio-protocol 2019;9(16)Disclosure of Interests:Meng Sun: None declared, Bence Réthi: None declared, Akilan Krishnamurthy: None declared, Vijay Joshua: None declared, Alexandra Circiumaru: None declared, Marianne Engström: None declared, Caroline Grönwall: None declared, Vivianne Malmström Grant/research support from: VM has had research grants from Janssen Pharmaceutica, Khaled Amara: None declared, Lars Klareskog: None declared, Heidi Wähämaa: None declared, Anca Catrina: None declared
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  • Kawauchi, K., et al. (författare)
  • Validation and atmospheric exploration of the sub-Neptune TOI-2136b around a nearby M3 dwarf
  • 2022
  • Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 666
  • Tidskriftsartikel (refereegranskat)abstract
    • Context. The NASA space telescope TESS is currently in the extended mission of its all-sky search for new transiting planets. Of the thousands of candidates that TESS is expected to deliver, transiting planets orbiting nearby M dwarfs are particularly interesting targets since they provide a great opportunity to characterize their atmospheres by transmission spectroscopy. Aims. We aim to validate and characterize the new sub-Neptune-sized planet candidate TOI-2136.01 orbiting a nearby M dwarf (d = 33.36 +/- 0.02 pc, T-eff = 3373 +/- 108 K) with an orbital period of 7.852 days. Methods. We use TESS data, ground-based multicolor photometry, and radial velocity measurements with the InfraRed Doppler (IRD) instrument on the Subaru Telescope to validate the planetary nature of TOI-2136.01, and estimate the stellar and planetary parameters. We also conduct high-resolution transmission spectroscopy to search for helium in its atmosphere. Results. We confirm that TOI-2136.01 (now named TOI-2136b) is a bona fide planet with a planetary radius of R-p = 2.20 +/- 0.07 R-circle plus and a mass of M-p = 4.7(-2.6)(+3.1) M-circle plus. We also search for helium 10830 angstrom absorption lines and place an upper limit on the equivalent width of <7.8 m angstrom and on the absorption signal of <1.44% with 95% confidence. Conclusions. TOI-2136b is a sub-Neptune transiting a nearby and bright star (J = 10.8 mag), and is a potentially hycean planet, which is a new class of habitable planets with large oceans under a H-2-rich atmosphere, making it an excellent target for atmospheric studies to understand the formation, evolution, and habitability of the small planets.
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  • Krishnamurthy, A, et al. (författare)
  • ACPA-INDUCED PAIN-BEHAVIOR, BONE LOSS AND TENDON INFLAMMATION IN MICE: A NOVEL MODEL FOR THE PRE-DISEASE PHASES OF ACPA-POSITIVE RHEUMATOID ARTHRITIS
  • 2020
  • Ingår i: ANNALS OF THE RHEUMATIC DISEASES. - : BMJ. - 0003-4967 .- 1468-2060. ; 79, s. 200-201
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • In rheumatoid arthritis (RA), anti-citrullinated protein antibodies (ACPAs) are associated with bone loss and pain. Recently, tenosynovitis has been suggested as a predicting factor for arthritis progression in individuals at-risk for RA.Objectives:We aimed to investigate if transfer of human ACPAs into mice could induce tenosynovitis and/or subclinical inflammation.Methods:Monoclonal ACPA (1325:04C03 and 1325:01B09) and control (1362:01E02) antibodies (mAbs) were generated from synovial plasma or memory B cells of RA patients. 2mg of combination of monoclonal ACPAs or control antibody were injected in BALB/c female mice (age 12-16 weeks) (n= 9). Pain-like behavior was monitored by measuring mechanical hypersensitivity using von Frey filaments every 3 days and estimation by up-down Dixon method. Bone morphometrics was analyzed by micro-CT. Using specially designed mobilization casts, dedicated mouse MRI coils, and gadolinium enhanced contrast medium, the hind limbs of these mice were scanned in a 9.4 T scanner and resulting T1-weighted images were evaluated for signs of soft tissue joint inflammation. The MRI images were scored for the presence of joint involvement and tendon inflammatory changes by 3 readers in a blinded manner.Figure 1.NAPA performed on healthy donor mo-DCs incubated with native, PAD2-citrullinated, and PAD4-citrullinated fibrinogen. Alpha, beta, and gamma chains of fibrinogen are shown separately. Each colored line represents a unique peptide. Nested peptides with a common core motif are shown in the same color. Grey bar denotes peptides with identical core motif between samples.Results:ACPAs (1325:04C03 and 1325:01B09) induced pain-like behavior (lasting for at least 4 weeks) and reduction of the trabecular and cortical bone thickness in the hind limbs as compared to control monoclonal antibodies (p<0.05). While no macroscopic or MRI signs of synovial inflammation were detected, MRI subclinical inflammation of the tendon sheaths was present in mice injected with ACPAs, but not in those injected with control mAb. Semi-quantitative scoring of the inflammatory tendon changes showed significant higher values in mice injected with ACPA (median of 1, range 0 to 2) than those injected with control mAb (median of 0, range 0 to 1).Conclusion:We show that ACPA induces pain-like behavior, bone loss and tendon sheath inflammation in mice, a model that mimics the preclinical state of ACPA positive RA.References:[1]Harre, U. et al. J Clin Invest (2012)[2]Krishnamurthy, A. et al. Ann Rheum Dis (2016, 2019), JI 2019[3]Wigerblad, G. et al. Ann Rheum Dis (2016, 2019)[4]KleyerA, Seminars in Arthritis and Rheumatism (2016)Disclosure of Interests:Akilan Krishnamurthy: None declared, Yogan Kisten: None declared, Alexandra Circiumaru: None declared, Koji Sakurabas: None declared, Patrik Jarvolli: None declared, Juan Jimenez Jimenez Andrade: None declared, Peter Damberg: None declared, Heidi Wähämaa: None declared, Vivianne Malmström Grant/research support from: VM has had research grants from Janssen Pharmaceutica, Lars Klareskog: None declared, Camilla Svensson: None declared, Bence Réthi: None declared, Anca Catrina: None declared
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