Centre for Youth Mental Health - Research Publications
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ItemRemote Control in Formation of 3D Multicellular Assemblies Using Magnetic Forces(AMER CHEMICAL SOC, 2019-05)Cell constructs have been utilized as building blocks in tissue engineering to closely mimic the natural tissue and also overcome some of the limitations caused by two-dimensional cultures or using scaffolds. External forces can be used to enhance the cells' adhesion and interaction and thus provide better control over production of these structures compared to methods like cell seeding and migration. In this paper, we demonstrate an efficient method to generate uniform, three-dimensional cell constructs using magnetic forces. This method produced spheroids with higher densities and more symmetrical structures than the commonly used centrifugation method for production of cell spheroids. It was also shown that shape of the cell constructs could be changed readily by using different patterns of magnetic field. The application of magnetic fields to impart forces on the cells enhanced the fusion of these spheroids, which could be used to produce larger and more complicated structures for future tissue engineering applications.
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ItemExtinction of a cocaine-taking context that protects against drug-primed reinstatement is dependent on the metabotropic glutamate 5 receptor(WILEY, 2015-05)We investigated the effects of extinguishing action-reward versus context-reward associations on drug-primed reinstatement, and the potential role of the metabotropic glutamate 5 receptor (mGlu5) in these different types of extinction in rats that self-administer cocaine. We observed that daily context extinction (non-reinforced exposures to the cocaine-taking context with retracted levers) was just as effective as daily lever extinction in reducing cocaine-primed reinstatement compared with passive abstinence. Additionally, systemic injections of the mGlu5 negative allosteric modulator MTEP (3-[(2-methyl-1,3-thiazol-4-yl)ethynyl]-pyridine) following each extinction session significantly impaired the ability of context extinction to reduce cocaine-primed reinstatement, without affecting reinstatement after lever extinction or passive abstinence.
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ItemGenetic Influences on Cost-Efficient Organization of Human Cortical Functional Networks(SOC NEUROSCIENCE, 2011-03-02)The human cerebral cortex is a complex network of functionally specialized regions interconnected by axonal fibers, but the organizational principles underlying cortical connectivity remain unknown. Here, we report evidence that one such principle for functional cortical networks involves finding a balance between maximizing communication efficiency and minimizing connection cost, referred to as optimization of network cost-efficiency. We measured spontaneous fluctuations of the blood oxygenation level-dependent signal using functional magnetic resonance imaging in healthy monozygotic (16 pairs) and dizygotic (13 pairs) twins and characterized cost-efficient properties of brain network functional connectivity between 1041 distinct cortical regions. At the global network level, 60% of the interindividual variance in cost-efficiency of cortical functional networks was attributable to additive genetic effects. Regionally, significant genetic effects were observed throughout the cortex in a largely bilateral pattern, including bilateral posterior cingulate and medial prefrontal cortices, dorsolateral prefrontal and superior parietal cortices, and lateral temporal and inferomedial occipital regions. Genetic effects were stronger for cost-efficiency than for other metrics considered, and were more clearly significant in functional networks operating in the 0.09-0.18 Hz frequency interval than at higher or lower frequencies. These findings are consistent with the hypothesis that brain networks evolved to satisfy competitive selection criteria of maximizing efficiency and minimizing cost, and that optimization of network cost-efficiency represents an important principle for the brain's functional organization.
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ItemThe operational environment and rotational acceleration of asteroid (101955) Bennu from OSIRIS-REx observations(NATURE PUBLISHING GROUP, 2019-03-19)During its approach to asteroid (101955) Bennu, NASA's Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) spacecraft surveyed Bennu's immediate environment, photometric properties, and rotation state. Discovery of a dusty environment, a natural satellite, or unexpected asteroid characteristics would have had consequences for the mission's safety and observation strategy. Here we show that spacecraft observations during this period were highly sensitive to satellites (sub-meter scale) but reveal none, although later navigational images indicate that further investigation is needed. We constrain average dust production in September 2018 from Bennu's surface to an upper limit of 150 g s-1 averaged over 34 min. Bennu's disk-integrated photometric phase function validates measurements from the pre-encounter astronomical campaign. We demonstrate that Bennu's rotation rate is accelerating continuously at 3.63 ± 0.52 × 10-6 degrees day-2, likely due to the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect, with evolutionary implications.
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ItemPsychosocial Well-Being and Functional Outcomes in Youth With Type 1 Diabetes 12 years After Disease Onset(AMER DIABETES ASSOC, 2010-07)OBJECTIVE: Type 1 diabetes in youth and community controls were compared on functional outcomes. Relationships were examined between psychosocial variables at diagnosis and functional outcome 12 years later. RESEARCH DESIGN AND METHODS: Participants were subjects with type 1 diabetes (n = 110, mean age 20.7 years, SD 4.3) and control subjects (n = 76, mean age 20.8 years, SD 4.0). The measures used included the Youth Self-Report and Young Adult Self-Report and a semi-structured interview of functional outcomes. Type 1 diabetes participants also provided information about current diabetes care and metabolic control from diagnosis. RESULTS: Type 1 diabetes participants and control subjects reported similar levels of current well-being but for the youth with type 1 diabetes, the mental health referral rates over the previous 12 years were higher by 19% and school completion rates were lower by 17%. Over one-third of clinical participants were not currently receiving specialist care and this group had higher mental health service usage in the past (61 vs. 33%) and lower current psychosocial well- being. Within the type 1 diabetes group, behavior problems, high activity, and low family cohesion at diagnosis predicted lower current well-being, but were not associated with metabolic control history. Poorer metabolic control was associated with higher mental health service usage. CONCLUSIONS: Type 1 diabetes participants report similar levels of current psychosocial well-being compared with control subjects, but higher levels of psychiatric morbidity since diagnosis and lower school completion rates. Psychiatric morbidity was associated with poor metabolic control and failure to transition to tertiary adult diabetes care.
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ItemPeripheral telomere length and hippocampal volume in adolescents with major depressive disorder(SPRINGERNATURE, 2015-11-10)Several studies have reported that adults with major depressive disorder have shorter telomere length and reduced hippocampal volumes. Moreover, studies of adult populations without major depressive disorder suggest a relationship between peripheral telomere length and hippocampal volume. However, the relationship of these findings in adolescents with major depressive disorder has yet to be explored. We examined whether adolescent major depressive disorder is associated with altered peripheral telomere length and hippocampal volume, and whether these measures relate to one another. In 54 unmedicated adolescents (13-18 years) with major depressive disorder and 63 well-matched healthy controls, telomere length was assessed from saliva using quantitative polymerase chain reaction methods, and bilateral hippocampal volumes were measured with magnetic resonance imaging. After adjusting for age and sex (and total brain volume in the hippocampal analysis), adolescents with major depressive disorder exhibited significantly shorter telomere length and significantly smaller right, but not left hippocampal volume. When corrected for age, sex, diagnostic group and total brain volume, telomere length was not significantly associated with left or right hippocampal volume, suggesting that these cellular and neural processes may be mechanistically distinct during adolescence. Our findings suggest that shortening of telomere length and reduction of hippocampal volume are already present in early-onset major depressive disorder and thus unlikely to be only a result of accumulated years of exposure to major depressive disorder.
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ItemAn investigation into the association of pre- and post-migration experiences on the self-rated health status among new resettled adult humanitarian refugees to Australia: a protocol for a mixed methods study.(Springer Science and Business Media LLC, 2019-04-30)BACKGROUND: Refugees are one of the most vulnerable groups in our society. They are at risk of poor physical and mental health outcomes, much of this attributed to traumatic events prior to migration and the additional risk factors refugees face in the host nations. However, how migration factors shape the health of resettling refugees is not well understood. This study uses a mixed methods approach to examine how pre- and post-migration factors shape the self-rated health of resettling adult refugees in an effort to address the current knowledge gap. METHODS: This study will use a sequential explanatory mixed method study design. We begin by analyzing resettlement and health data from the 'Building a New Life In Australia' longitudinal study of humanitarian refugees resettled in Australia to identify significant associations between migration factors and refugee health. Then, a series of semi-structured interviews with resettled refugees will further explore the lived experiences of refugees with respect to the relationship between migration and refugee health. Finally, we will integrate both sets of findings to develop a detailed understanding of how and why migratory factors contribute to refugee health during resettlement. DISCUSSION: There is a paucity of studies that examine the multidimensional nature of refugee health during resettlement and as a result, little is understood about their resettlement health needs. This information is required to inform existing or new resettlement interventions to help promote or improve refugee health. To overcome these limitations in the research knowledge, this study will use a mixture of study methods to illustrate the complex and multifaceted determinants of refugee health during resettlement in Australia.
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ItemImproving access to primary healthcare for vulnerable populations in Australia and Canada: protocol for a mixed-method evaluation of six complex interventions.(BMJ, 2019-07-27)INTRODUCTION: Access to primary healthcare (PHC) has a fundamental influence on health outcomes, particularly for members of vulnerable populations. Innovative Models Promoting Access-to-Care Transformation (IMPACT) is a 5-year research programme built on community-academic partnerships. IMPACT aims to design, implement and evaluate organisational innovations to improve access to appropriate PHC for vulnerable populations. Six Local Innovation Partnerships (LIPs) in three Australian states (New South Wales, Victoria and South Australia) and three Canadian provinces (Ontario, Quebec and Alberta) used a common approach to implement six different interventions. This paper describes the protocol to evaluate the processes, outcomes and scalability of these organisational innovations. METHODS AND ANALYSIS: The evaluation will use a convergent mixed-methods design involving longitudinal (pre and post) analysis of the six interventions. Study participants include vulnerable populations, PHC practices, their clinicians and administrative staff, service providers in other health or social service organisations, intervention staff and members of the LIP teams. Data were collected prior to and 3-6 months after the interventions and included interviews with members of the LIPs, organisational process data, document analysis and tools collecting the cost of components of the intervention. Assessment of impacts on individuals and organisations will rely on surveys and semistructured interviews (and, in some settings, direct observation) of participating patients, providers and PHC practices. ETHICS AND DISSEMINATION: The IMPACT research programme received initial ethics approval from St Mary's Hospital (Montreal) SMHC #13-30. The interventions received a range of other ethics approvals across the six jurisdictions. Dissemination of the findings should generate a deeper understanding of the ways in which system-level organisational innovations can improve access to PHC for vulnerable populations and new knowledge concerning improvements in PHC delivery in health service utilisation.
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ItemIncreased Extent of and Risk Factors for Pandemic (H1N1) 2009 and Seasonal Influenza among Children, Israel(CENTERS DISEASE CONTROL, 2011-09)During the pandemic (H1N1) 2009 outbreak in Israel, incidence rates among children were 2× higher than that of the previous 4 influenza seasons; hospitalization rates were 5× higher. Children hospitalized for pandemic (H1N1) 2009 were older and had more underlying chronic diseases than those hospitalized for seasonal influenza.
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ItemThe association of migration experiences on the self-rated health status among adult humanitarian refugees to Australia: an analysis of a longitudinal cohort study.(Springer Science and Business Media LLC, 2019-08-22)BACKGROUND: Refugees are potentially at an increased risk for health problems due to their past and current migration experiences. How migration factors shape refugee health is not well understood. We examined the association between migration factors and the self-rated general health of adult humanitarian refugees living in Australia. METHODS: We analyzed the first three waves of data from the 'Building A New Life In Australia' longitudinal survey of 2399 humanitarian refugees resettled in Australia. The study outcome was self-rated health measured by the 36-Item Short Form Health Survey. Predictors were migration process and resettlement factors. We used generalized linear mixed models to investigate the relationship between predictor and outcome variables. RESULTS: Poor general health persisted among this refugee population at high levels throughout the three-year follow-up. At baseline, 35.7% (95% CI: 33.8-37.7%) of the study population reported poorer general health. Female gender, increasing age and post-migration financial stressors were positively associated with poorer general health. Having a university degree and absence of chronic health conditions were seemingly protective against declining general health (OR: 0.50; 95% CI: 0.65-1.81 and OR: 0.15, 95% CI: 0.09-1.04, respectively). CONCLUSION: Our results show that there is persisting high prevalence of poorer general health among adult refugees across the initial years of resettlement in Australia. This finding suggests unmet health needs which may be compounded by the challenges of resettlement in a new society, highlighting the need for increased clinical awareness of this sustained health burden to help inform and prepare refugee health care and settlement service providers.