Advancing Understanding of Toddler and Preschooler Sport Participation: A Research Area in its Infancy

The purpose of this doctoral dissertation was to advance understanding of early-years (<6) sport and organized physical activity (OPA) participation. This research involved a scoping review, followed by a qualitative case-study, which drew upon multiple data collection methods (semi-structured interviews, observation) from multiple perspectives (toddlers, preschoolers, parents, coaches; N=27), providing a comprehensive picture of early-years sport (Baxter & Jack, 2008; Creswell, 2012). Specific goals across four manuscripts/studies were to: (1) systematically review and synthesize research examining developmental outcomes associated with early-years sport involvement, (2) explore parents, coaches, and childrens perceived outcomes and experiences of early-years sport, (3) explore early-years sport pathways and patterns of engagement, and (4) explore coaches experiences in early-years sport, focusing on challenges-faced and strategies drawn-upon for effective coaching. Scoping review findings (Study 1) offer preliminary evidence that early sport and OPA participation is related to primarily positive outcomes (e.g., enhanced social skills, pro-social behaviours, self-regulation); however, negative and inconclusive outcomes were also identified. Study 2 showed some alignment between parents, coaches, and childrens perceived outcomes and experiences in early-years sport in the areas of physical activity, energy management, sport skill acquisition, physical literacy, learning to win and lose, and social/life skills. Findings were moderated by childrens age, developmental capacities, sport readiness, and attendance in other programs (e.g., music, preschool). Study 3 offered insight into early-years sport, OPA, and unstructured sport pathways, highlighting common features and engagement patterns within programming (e.g., structure, movement/sport skill focus, play-based activities). Findings suggest existing life-span sport participation/development models may not align with delivery of and experiences within early-years sport programming. Finally, Study 4 highlighted unique challenges and strategies for effective coaching across diverse early-years coaching contexts, showing differences according to program-type (i.e., private and club-based versus community-based). Collectively, this research advances limited understanding of early-years sport and OPA participation, which may help inform key stakeholders decisions around early-years sport programming; several important future research directions are outlined

Does Childhood Executive Function Predict Adolescent Functional Outcomes in Girls with ADHD?

We prospectively followed an ethnically and socioeconomically diverse sample of preadolescent girls with ADHD (n = 140) and matched comparison girls (n = 88) over a period of 5 years, from middle childhood through early/mid-adolescence. Our aim was to examine the ability of measures of childhood executive function (EF) to predict functional outcomes in adolescence. Measures of neuropsychological functioning comprised the childhood predictors, with academic, social, and global functioning serving as adolescent criterion measures. Results indicated that childhood EF predicted (a) academic achievement and social functioning across our entire sample (independent of diagnostic group status) and (b) global functioning only in girls with ADHD (independent of IQ). These results highlight the non-specificity of EF deficits and suggest the importance of assessing and developing interventions that target EF impairments, particularly in those at high-risk for negative outcomes, in order to prevent long-term difficulties across a range of important functional domains

Advancing Understanding of Toddler and Preschooler Sport Participation: A Research Area in its Infancy

The purpose of this doctoral dissertation was to advance understanding of early-years (<6) sport and organized physical activity (OPA) participation. This research involved a scoping review, followed by a qualitative case-study, which drew upon multiple data collection methods (semi-structured interviews, observation) from multiple perspectives (toddlers, preschoolers, parents, coaches; N=27), providing a comprehensive picture of early-years sport (Baxter & Jack, 2008; Creswell, 2012). Specific goals across four manuscripts/studies were to: (1) systematically review and synthesize research examining developmental outcomes associated with early-years sport involvement, (2) explore parents, coaches, and childrens perceived outcomes and experiences of early-years sport, (3) explore early-years sport pathways and patterns of engagement, and (4) explore coaches experiences in early-years sport, focusing on challenges-faced and strategies drawn-upon for effective coaching. Scoping review findings (Study 1) offer preliminary evidence that early sport and OPA participation is related to primarily positive outcomes (e.g., enhanced social skills, pro-social behaviours, self-regulation); however, negative and inconclusive outcomes were also identified. Study 2 showed some alignment between parents, coaches, and childrens perceived outcomes and experiences in early-years sport in the areas of physical activity, energy management, sport skill acquisition, physical literacy, learning to win and lose, and social/life skills. Findings were moderated by childrens age, developmental capacities, sport readiness, and attendance in other programs (e.g., music, preschool). Study 3 offered insight into early-years sport, OPA, and unstructured sport pathways, highlighting common features and engagement patterns within programming (e.g., structure, movement/sport skill focus, play-based activities). Findings suggest existing life-span sport participation/development models may not align with delivery of and experiences within early-years sport programming. Finally, Study 4 highlighted unique challenges and strategies for effective coaching across diverse early-years coaching contexts, showing differences according to program-type (i.e., private and club-based versus community-based). Collectively, this research advances limited understanding of early-years sport and OPA participation, which may help inform key stakeholders decisions around early-years sport programming; several important future research directions are outlined

Lymphatic endothelial cells promote productive and latent HIV infection in resting CD4+ T cells

Abstract Background An HIV cure has not yet been achieved because latent viral reservoirs persist, particularly in resting CD4+ T lymphocytes. In vitro, it is difficult to infect resting CD4+ T cells with HIV-1, but infections readily occur in vivo. Endothelial cells (EC) line the lymphatic vessels in the lymphoid tissues and regularly interact with resting CD4+ T cells in vivo. Others and we have shown that EC promoted productive and latent HIV infection of resting CD4+ T cells. However, the EC used in previous studies were from human umbilical cords (HUVEC), which are macrovascular; whereas EC residing in the lymphoid tissues are microvascular. Methods In this study, we investigated the effects of microvascular EC stimulation of resting CD4+ T cells in establishing viral infection and latency. Human resting and activated CD4+ T cells were cultured alone or with endothelial cells and infected with a pseudotyped virus. Infection levels, indicated by green fluorescent protein expression, were measured with flow cytometry and data was analyzed using Flowing Software and Excel. Results We confirmed that EC from lymphatic tissue (LEC) were able to promote HIV infection and latency formation in resting CD4+ T cells while keeping them in resting phenotype, and that IL-6 was involved in LEC stimulation of CD4+ T cells. However, there are some differences between stimulation by LEC and HUVEC. Unlike HUVEC stimulation, we demonstrated that LEC stimulation of resting memory T cells does not depend on major histocompatibility complex class II (MHC II) interactions with T cell receptors (TCR) and that CD2-CD58 interactions were not involved in LEC stimulation of resting T cells. LEC also secreted lower levels of IL-6 than HUVEC. We also found that LEC stimulation increases HIV infection rates in activated CD4+ T cells. Conclusions While differences in T cell stimulation between lymphatic EC and HUVEC were observed, we confirmed that similar to macrovascular EC stimulation, microvascular EC stimulation promotes direct HIV infection and latency formation in resting CD4+ T cells without T cell activation. LEC stimulation also increased infection rates in activated CD4+ T cells. Additionally, the present study established a physiologically more relevant model of EC interactions with resting CD4+ T cells and further highlighted the importance of investigating the roles of EC in HIV infection and latency in both resting and activated CD4+ T cells

Progression of Fatty Liver Disease in Children Receiving Standard of Care Lifestyle Advice

Background &amp; aimsNonalcoholic fatty liver disease (NAFLD) is the most common pediatric chronic liver disease. Little is known about outcomes in recognized youth.MethodsWe compared paired liver biopsies from 122 of 139 children with NAFLD (74% male; 64% white; 71% Hispanic; mean age, 13 ± 3 years; age range, 8-17 years) who received placebo and standard of care lifestyle advice in 2 double-blind, randomized clinical trials within the nonalcoholic steatohepatitis (NASH) clinical research network from 2005 through 2015. We analyzed histologic changes with respect to baseline and longitudinal change in clinical variables using regression analysis.ResultsAt enrollment, 31% of the children had definite NASH, 34% had borderline zone 1 NASH, 13% had borderline zone 3 NASH, and 21% had fatty liver but not NASH. Over a mean period of 1.6 ± 0.4 years, borderline or definite NASH resolved in 29% of the children, whereas 18% of the children with fatty liver or borderline NASH developed definite NASH. Fibrosis improved in 34% of the children but worsened in 23%. Any progression to definite NASH and/or in fibrosis was associated with adolescent age, and higher waist circumference, levels of alanine or aspartate aminotransferase, total and low-density lipoprotein cholesterol at baseline (&lt;0.05), and over follow-up time, with increasing level of alanine aminotransferase, hemoglobin A1C (P&lt;.05), gamma-glutamyl transferase and development of type 2 diabetes (P&lt;.01). Increasing level of gamma-glutamyl transferase was also associated with reduced odds of any improvement (P&nbsp;= .003).ConclusionsOne-third of children with NAFLD enrolled in placebo groups of clinical trials had histologic features of progression within 2 years, in association with increasing obesity and serum levels of aminotransferases and loss of glucose homeostasis