18 research outputs found

    Comparative lung toxicity of engineered nanomaterials utilizing in vitro, ex vivo and in vivo approaches

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    BackgroundAlthough engineered nanomaterials (ENM) are currently regulated either in the context of a new chemical, or as a new use of an existing chemical, hazard assessment is still to a large extent reliant on information from historical toxicity studies of the parent compound, and may not take into account special properties related to the small size and high surface area of ENM. While it is important to properly screen and predict the potential toxicity of ENM, there is also concern that current toxicity tests will require even heavier use of experimental animals, and reliable alternatives should be developed and validated. Here we assessed the comparative respiratory toxicity of ENM in three different methods which employed in vivo, in vitro and ex vivo toxicity testing approaches.MethodsToxicity of five ENM (SiO2 (10), CeO2 (23), CeO2 (88), TiO2 (10), and TiO2 (200); parentheses indicate average ENM diameter in nm) were tested in this study. CD-1 mice were exposed to the ENM by oropharyngeal aspiration at a dose of 100ÎŒg. Mouse lung tissue slices and alveolar macrophages were also exposed to the ENM at concentrations of 22–132 and 3.1-100ÎŒg/mL, respectively. Biomarkers of lung injury and inflammation were assessed at 4 and/or 24hr post-exposure.ResultsSmall-sized ENM (SiO2 (10), CeO2 (23), but not TiO2 (10)) significantly elicited pro-inflammatory responses in mice (in vivo), suggesting that the observed toxicity in the lungs was dependent on size and chemical composition. Similarly, SiO2 (10) and/or CeO2 (23) were also more toxic in the lung tissue slices (ex vivo) and alveolar macrophages (in vitro) compared to other ENM. A similar pattern of inflammatory response (e.g., interleukin-6) was observed in both ex vivo and in vitro when a dose metric based on cell surface area (ÎŒg/cm2), but not culture medium volume (ÎŒg/mL) was employed.ConclusionExposure to ENM induced acute lung inflammatory effects in a size- and chemical composition-dependent manner. The cell culture and lung slice techniques provided similar profiles of effect and help bridge the gap in our understanding of in vivo, ex vivo, and in vitro toxicity outcomes.Electronic supplementary materialThe online version of this article (doi:10.1186/s12951-014-0047-3) contains supplementary material, which is available to authorized users

    Mixed-methods study protocol for an evaluation of the mental health transition navigator model in child and adolescent mental health services : the Navigator Evaluation Advancing Transitions (NEAT) study

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    INTRODUCTION: Transition from child and adolescent mental health services (CAMHS) to community or adult mental health services (AMHS) is a highly problematic health systems hurdle, especially for transition-aged youth. A planned and purposeful transition process is often non-existent or experienced negatively by youth and their caregivers. Stakeholders, including youth and their caregivers, have demanded interventions to support more effective transitions, such a transition navigator. The transition navigator model uses a navigator to facilitate complex transitions from acute care CAMHS to community or AMHS. However, despite the widespread implementation of this model, there has been no evaluation of the programme, hindering its scalability. This paper describes the study protocol of the Navigator Evaluation Advancing Transitions study that aims to collaborate with patients, caregivers and clinicians in the evaluation of the navigator model. METHODS AND ANALYSIS: A pre and post mixed-method study will be conducted, using the Triple Aim Framework, to evaluate the navigator model. We will recruit participants from one large tertiary and two community hospitals in Toronto, Canada. For the quantitative portion of the study, we will recruit a sample of 45 youth (15 at each site), aged 16-18, and their caregivers at baseline (referral to navigator) (T1) and 6 months (T2). Youth and caregiver participants will complete a set of standardised measures to assess mental health, service utilisation, and satisfaction outcomes. For the qualitative portion of the study, semistructured interviews will be conducted at 6 months (T2) with youth, their caregivers and clinicians to better understand their experience and satisfaction with the model. ETHICS AND DISSEMINATION: Research Ethics Board (REB) approval has been obtained from the lead research sites, the University of Toronto and the Hospital for Sick Children. The results of the study will be reported in peer-reviewed publications, webinars and conferences and to all relevant stakeholders

    Observation of gravitational waves from the coalescence of a 2.5−4.5 M⊙ compact object and a neutron star

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    Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

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    Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≀0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

    Ultralight vector dark matter search using data from the KAGRA O3GK run

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    Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

    571 Effectiveness of Compression Garments with Silicone versus Compression Garments Alone on Hypertrophic Scar

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    Introduction: Only a few studies have looked at the effects of custom compression garments with silicone sheeting sewn into the garments versus garments alone on scar management. This retrospective study hypothesizes that garments with silicone will improve the Modified Vancouver Scar Scale (mVSS) total scores and sub-scores of pliability, vascularity and height of hypertrophic scars(HTS) when compared to garments alone. Methods: This is a retrospective study of patients that were autografted or required >21 days to heal and placed in compression garments with or without silicone between 2013 and 2020. Charts were reviewed and mVSS scores from 91 patients with 191 scar locations (134 silicone/57 non-silicone) were collected at 1,3,6,9,12 months. Descriptive statistics were used to describe the sample characteristics. The mean mVSS score and mean sub-scores for pliability, height and vascularity were computed at 1,3,6,9,12 months and reported for the silicone and non-silicone groups. Results: When comparing the two groups at 9-months (with 45% of initial scars scored), the silicone group had a greater decrease in numerical value and overall % change from 1 to 9-months as compared to the non-silicone group in all areas. The results at 12-months (with 30% of initial scars scored) demonstrated the non-silicone group had a greater decrease in numerical value and % change in height and overall score. Pliability had a 25% improvement in silicone group compared to 16% change in non-silicone group. Vascularity % change was similar with a 47% change in non-silicone group and 46% change in silicone group. The scars in silicone group that were analyzed at 12-months were consistently scored higher across prior months.  Conclusions: Silicone group demonstrated improved %change in all categories at 9-months and in pliability %change at 12-months despite the decreased sample size. Pliability is improved with the use of silicone garments. Although the 12-month %change in mean for height, vascularity and total score did not show improvement over non-silicone, this reflects the return patients having significant scarring throughout treatment and needing continued interventions. These returning patients had scars in the non-silicone group as well that were also rated resulting in the disparity in the groups. The patients in the silicone group with improved scars did not continue follow-up at 12-months. Further research with focus on 9-18 month follow-up mVSS scores is warranted. Applicability of Research to Practice: Effectiveness of adding silicone to garments in scar treatment

    The Role of Sensory Innervation in Homeostatic and Injury-Induced Corneal Epithelial Renewal

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    The cornea is the window through which we see the world. Corneal clarity is required for vision, and blindness occurs when the cornea becomes opaque. The cornea is covered by unique transparent epithelial cells that serve as an outermost cellular barrier bordering between the cornea and the external environment. Corneal sensory nerves protect the cornea from injury by triggering tearing and blink reflexes, and are also thought to regulate corneal epithelial renewal via unknown mechanism(s). When protective corneal sensory innervation is absent due to infection, trauma, intracranial tumors, surgery, or congenital causes, permanent blindness results from repetitive epithelial microtraumas and failure to heal. The condition is termed neurotrophic keratopathy (NK), with an incidence of 5:10,000 people worldwide. In this report, we review the currently available therapeutic solutions for NK and discuss the progress in our understanding of how the sensory nerves induce corneal epithelial renewal
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