286 research outputs found

    Dendritic cells license regulatory B cells to produce IL-10 and mediate suppression of antigen-specific CD8 T cells

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    Regulatory B cells (Bregs) suppress and reduce autoimmune pathology. However, given the variety of Breg subsets, the role of Bregs in the pathogenesis of type 1 diabetes is still unclear. Here, we dissect this fundamental mechanism. We show that natural protection from type 1 diabetes in nonobese diabetic (NOD) mice is associated with increased numbers of IL-10-producing B cells, while development of type 1 diabetes in NOD mice occurs in animals with compromised IL-10 production by B cells. However, B cells from diabetic mice regain IL-10 function if activated by the innate immune receptor TLR4 and can suppress insulin-specific CD8 T cells in a dendritic cell (DC)-dependent, IL-10-mediated fashion. Suppression of CD8 T cells is reliant on B-cell contact with DCs. This cell contact results in deactivation of DCs, inducing a tolerogenic state, which in turn can regulate pathogenic CD8 T cells. Our findings emphasize the importance of DC–Breg interactions during the development of type 1 diabetes

    Testing the excitation/inhibition imbalance hypothesis in a mouse model of the autism spectrum disorder: in vivo neurospectroscopy and molecular evidence for regional phenotypes

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    Background Excitation/inhibition (E/I) imbalance remains a widely discussed hypothesis in autism spectrum disorders (ASD). The presence of such an imbalance may potentially define a therapeutic target for the treatment of cognitive disabilities related to this pathology. Consequently, the study of monogenic disorders related to autism, such as neurofibromatosis type 1 (NF1), represents a promising approach to isolate mechanisms underlying ASD-related cognitive disabilities. However, the NF1 mouse model showed increased γ-aminobutyric acid (GABA) neurotransmission, whereas the human disease showed reduced cortical GABA levels. It is therefore important to clarify whether the E/I imbalance hypothesis holds true. We hypothesize that E/I may depend on distinct pre- and postsynaptic push-pull mechanisms that might be are region-dependent. Methods In current study, we assessed two critical components of E/I regulation: the concentration of neurotransmitters and levels of GABA(A) receptors. Measurements were performed across the hippocampi, striatum, and prefrontal cortices by combined in vivo magnetic resonance spectroscopy (MRS) and molecular approaches in this ASD-related animal model, the Nf1 +/− mouse. Results Cortical and striatal GABA/glutamate ratios were increased. At the postsynaptic level, very high receptor GABA(A) receptor expression was found in hippocampus, disproportionately to the small reduction in GABA levels. Gabaergic tone (either by receptor levels change or GABA/glutamate ratios) seemed therefore to be enhanced in all regions, although by a different mechanism. Conclusions Our data provides support for the hypothesis of E/I imbalance in NF1 while showing that pre- and postsynaptic changes are region-specific. All these findings are consistent with our previous physiological evidence of increased inhibitory tone. Such heterogeneity suggests that therapeutic approaches to address neurochemical imbalance in ASD may need to focus on targets where convergent physiological mechanisms can be found.</p

    Rationale, design and methods for a randomised and controlled trial of the impact of virtual reality games on motor competence, physical activity, and mental health in children with developmental coordination disorder.

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    This is the final version of the article. Available from BioMed Central via the DOI in this record.BACKGROUND: A healthy start to life requires adequate motor development and physical activity participation. Currently 5-15% of children have impaired motor development without any obvious disorder. These children are at greater risk of obesity, musculoskeletal disorders, low social confidence and poor mental health. Traditional electronic game use may impact on motor development and physical activity creating a vicious cycle. However new virtual reality (VR) game interfaces may provide motor experiences that enhance motor development and lead to an increase in motor coordination and better physical activity and mental health outcomes. VR games are beginning to be used for rehabilitation, however there is no reported trial of the impact of these games on motor coordination in children with developmental coordination disorder. METHODS: This cross-over randomised and controlled trial will examine whether motor coordination is enhanced by access to active electronic games and whether daily activity, attitudes to physical activity and mental health are also enhanced. Thirty children aged 10-12 years with poor motor coordination (≤ 15th percentile) will be recruited and randomised to a balanced ordering of 'no active electronic games' and 'active electronic games'. Each child will participate in both conditions for 16 weeks, and be assessed prior to participation and at the end of each condition. The primary outcome is motor coordination, assessed by kinematic and kinetic motion analysis laboratory measures. Physical activity and sedentary behaviour will be assessed by accelerometry, coordination in daily life by parent report questionnaire and attitudes to physical activity, self-confidence, anxiety and depressed mood will be assessed by self report questionnaire. A sample of 30 will provide a power of > 0.9 for detecting a 5 point difference in motor coordination on the MABC-2 TIS scale (mean 17, sd = 5). DISCUSSION: This is the first trial to examine the impact of new virtual reality games on motor coordination in children with developmental coordination disorder. The findings will provide critical information to understand whether these electronic games can be used to have a positive impact on the physical and mental health of these children. Given the importance of adequate motor coordination, physical activity and mental health in childhood, this project can inform interventions which could have a profound impact on the long term health of this group of children. TRIAL REGISTRATION: Australia and New Zealand Clinical Trials Register (ANZCTR): ACTRN12611000400965.This randomised and controlled trial is funded by the National Health and Medical Research Council (NHMRC) of Australia through project grant #533526. Professor Leon Straker and Doctor Anne Smith are supported by fellowships awarded from the NHMRC. No funding or other input to the study has been received from any electronic game design, manufacture or supply company

    Coexistence of Chiari 2 malformation and moyamoya syndrome in a 17-year-old girl.

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    A 17-year-old female with Chiari 2 malformation developed cerebral infarction with angiographically typical bilateral moyamoya vessels manifesting as sudden onset of moderate left hemiparesis. Magnetic resonance imaging revealed multiple infarcts in the right frontal lobe, agenesis of the corpus callosum, upward herniation of the dorsal cerebellum, tectal beak of the midbrain, and downward herniation of the cerebellar vermis. Cerebral angiography demonstrated occlusion of the bilateral internal carotid arteries and basal moyamoya vessels. Single photon emission computed tomography showed significantly reduced regional cerebral blood flow in the right frontoparietal cortex. The cerebral vascular reactivity to acetazolamide was diminished in both cerebral hemispheres. She underwent superficial temporal artery-middle cerebral artery anastomosis combined with encephalo-myo-synangiosis on the right, and on the left 6 months later. Cerebral angiography performed 4 months after the second operation showed good patency of the bypasses and substantial collateral vessels in both cerebral hemispheres. This association may have happened by chance, and a common etiology is uncertain, but a currently undetermined genomic component might have contributed to the disease progression

    Measurement and interpretation of same-sign W boson pair production in association with two jets in pp collisions at s = 13 TeV with the ATLAS detector

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    This paper presents the measurement of fducial and diferential cross sections for both the inclusive and electroweak production of a same-sign W-boson pair in association with two jets (W±W±jj) using 139 fb−1 of proton-proton collision data recorded at a centre-of-mass energy of √s = 13 TeV by the ATLAS detector at the Large Hadron Collider. The analysis is performed by selecting two same-charge leptons, electron or muon, and at least two jets with large invariant mass and a large rapidity diference. The measured fducial cross sections for electroweak and inclusive W±W±jj production are 2.92 ± 0.22 (stat.) ± 0.19 (syst.)fb and 3.38±0.22 (stat.)±0.19 (syst.)fb, respectively, in agreement with Standard Model predictions. The measurements are used to constrain anomalous quartic gauge couplings by extracting 95% confdence level intervals on dimension-8 operators. A search for doubly charged Higgs bosons H±± that are produced in vector-boson fusion processes and decay into a same-sign W boson pair is performed. The largest deviation from the Standard Model occurs for an H±± mass near 450 GeV, with a global signifcance of 2.5 standard deviations

    Search for pair production of squarks or gluinos decaying via sleptons or weak bosons in final states with two same-sign or three leptons with the ATLAS detector

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    A search for pair production of squarks or gluinos decaying via sleptons or weak bosons is reported. The search targets a final state with exactly two leptons with same-sign electric charge or at least three leptons without any charge requirement. The analysed data set corresponds to an integrated luminosity of 139 fb−1 of proton-proton collisions collected at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC. Multiple signal regions are defined, targeting several SUSY simplified models yielding the desired final states. A single control region is used to constrain the normalisation of the WZ + jets background. No significant excess of events over the Standard Model expectation is observed. The results are interpreted in the context of several supersymmetric models featuring R-parity conservation or R-parity violation, yielding exclusion limits surpassing those from previous searches. In models considering gluino (squark) pair production, gluino (squark) masses up to 2.2 (1.7) TeV are excluded at 95% confidence level

    Combination of searches for heavy spin-1 resonances using 139 fb−1 of proton-proton collision data at s = 13 TeV with the ATLAS detector

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    A combination of searches for new heavy spin-1 resonances decaying into different pairings of W, Z, or Higgs bosons, as well as directly into leptons or quarks, is presented. The data sample used corresponds to 139 fb−1 of proton-proton collisions at = 13 TeV collected during 2015–2018 with the ATLAS detector at the CERN Large Hadron Collider. Analyses selecting quark pairs (qq, bb, , and tb) or third-generation leptons (τν and ττ) are included in this kind of combination for the first time. A simplified model predicting a spin-1 heavy vector-boson triplet is used. Cross-section limits are set at the 95% confidence level and are compared with predictions for the benchmark model. These limits are also expressed in terms of constraints on couplings of the heavy vector-boson triplet to quarks, leptons, and the Higgs boson. The complementarity of the various analyses increases the sensitivity to new physics, and the resulting constraints are stronger than those from any individual analysis considered. The data exclude a heavy vector-boson triplet with mass below 5.8 TeV in a weakly coupled scenario, below 4.4 TeV in a strongly coupled scenario, and up to 1.5 TeV in the case of production via vector-boson fusion

    Software Performance of the ATLAS Track Reconstruction for LHC Run 3

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    Charged particle reconstruction in the presence of many simultaneous proton–proton (pp) collisions in the LHC is a challenging task for the ATLAS experiment’s reconstruction software due to the combinatorial complexity. This paper describes the major changes made to adapt the software to reconstruct high-activity collisions with an average of 50 or more simultaneous pp interactions per bunch crossing (pileup) promptly using the available computing resources. The performance of the key components of the track reconstruction chain and its dependence on pile-up are evaluated, and the improvement achieved compared to the previous software version is quantified. For events with an average of 60 pp collisions per bunch crossing, the updated track reconstruction is twice as fast as the previous version, without significant reduction in reconstruction efficiency and while reducing the rate of combinatorial fake tracks by more than a factor two
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