White Matter Plasticity in Reading-Related Pathways Differs in Children Born Preterm and at Term: A Longitudinal Analysis

Children born preterm (PT) are at risk for white matter injuries based on complications of prematurity. They learn to read but on average perform below peers born full term (FT). Studies have yet to establish whether properties of white matter pathways at the onset of learning to read are associated with individual variation later in reading development in PT children. Here, we asked whether fractional anisotropy (FA) at age 6 years is associated with reading outcome at age 8 years in PT children in the same pathways as previously demonstrated in a sample of FT children. PT (n = 34, mean gestational age = 29.5 weeks) and FT children (n = 37) completed diffusion MRI and standardized measures of non-verbal IQ, language, and phonological awareness at age 6 years. Reading skills were assessed at age 8 years. Mean tract-FA was extracted from pathways that predicted reading outcome in children born FT: left arcuate fasciculus (Arc), bilateral superior longitudinal fasciculus (SLF), and left inferior cerebellar peduncle (ICP). We explored associations in additional pathways in the PT children: bilateral inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, and uncinate fasciculus. Linear regression models examined whether the prediction of reading outcome at age 8 years based on mean tract-FA at age 6 years was moderated by birth group. Children born PT and FT did not differ significantly in tract-FA at age 6 years or in reading at age 8 years. Sex, socioeconomic status, and non-verbal IQ at age 6 years were associated with reading outcome and were included as covariates in all models. Birth group status significantly moderated associations between reading outcome and mean tract-FA only in the left Arc, right SLF, and left ICP, before and after consideration of pre-literacy skills. Microstructural properties of these cerebral and cerebellar pathways predicted later reading outcome in FT but not in PT children. Children born PT may rely on alternative pathways to achieve fluent reading. These findings have implications for plasticity of neural organization after early white matter injury

Genotyping a novel Theileria parva candidate vaccine antigen in cattle- and buffalo-derived parasites

Theileriosis is a lymphoproliferative tick-borne disease of cattle and other wild ruminants, caused by infection with a protozoan, Theileria parva. The disease is prevalent in cattle throughout Central, East and southern Africa, where it threatens 50% of the cattle population. There are various control and treatments methods used against theileriosis; however, they all have limitations. The available live immunisation method, the Muguga cocktail, does not confer protection against all field strains, particularly buffalo-derived T. parva. Attempts to develop a subunit vaccine have been promising but these have shown limited efficacy due to antigenic and genetic diversity of T. parva strains in the field. Thus, there is a need to search for additional vaccine candidates. A related study has identified potential vaccine candidates using a genome-wide in silico approach. Consequently, the aim of this study was to genotype one of the identified antigens. TP04_0028 was selected for genotyping among candidate genes with high expression levels in the schizont stage of both cattle- and buffalo-derived T. parva isolates. Specific primers were designed and optimised for PCR amplification and sequencing. The comprehensive analysis of sequences from 17 cattle- and 17 buffalo-derived T. parva, from East and southern Africa, showed conservation in 12 (60%) of the 20 TP04_0028 predicted epitopes, in both parasite types, irrespective of geographical origin. Eighteen of the 20 predicted epitopes are conserved amongst different BoLA alleles and an area of 7 overlapping epitopes could be the starting point for initial experimental evaluation of the immunogenic properties of TP04_0028. Once the immunogenicity of these epitopes have been tested and the extent to provide protection from cattle- and buffalo-derived infections have been verified, they may be considered for vaccine development.Dissertation (MSc (Veterinary Science))--University of Pretoria, 2019.Veterinary Tropical DiseasesMSc (Veterinary Science)Unrestricte

White Matter Microstructural Properties of the Superior Cerebellar Peduncles Predict Change in Internalizing Symptoms in Adolescent Girls

Internalizing symptoms typically emerge in adolescence and are more prevalent in females than in males; in contrast, externalizing symptoms typically emerge in childhood and are more commonly observed in males. Previous research has implicated aspects of white matter organization, including fractional anisotropy (FA), of cerebral tracts in both internalizing and externalizing symptoms. Although the cerebellum has been posited to integrate limbic and cortical regions, its role in psychopathology is not well understood. In this longitudinal study, we investigated whether FA of the superior (SCP), middle, and inferior cerebellar peduncles predict change in symptoms and whether sex moderates this association. 111 adolescents completed the Youth Self-Report, assessing symptoms at baseline (ages 9-13 years) and again two years later. Participants also underwent diffusion-weighted imaging at baseline. We used deterministic tractography to segment and compute mean FA of the cerebellar peduncles. Lower FA of the right SCP at baseline predicted increases in internalizing symptoms in females only (t(103)=−0.47, p=.020). Lower FA in the right SCP and inferior cerebellar peduncle also predicted increases in externalizing symptoms, but these associations did not survive multiple comparisons correction. There was no association between FA of the cerebellar peduncles and change in symptoms in males, or between middle cerebellar peduncle FA and symptom changes in males or females. Organizational properties of the SCP may be a sex-specific marker of internalizing symptom changes in adolescence. The cerebellar peduncles should be explored further in future studies to elucidate sex differences in internalizing and externalizing symptoms

Early Life Stress Predicts Depressive Symptoms in Adolescents During the COVID-19 Pandemic: The Mediating Role of Perceived Stress

Background: Exposure to early life stress (ELS) is alarmingly prevalent, and has been linked to the high rates of depression documented in adolescence. Researchers have theorized that ELS may increase adolescents’ vulnerability or reactivity to the effects of subsequent stressors, placing them at higher risk for developing symptoms of depression. Methods: We tested this formulation in a longitudinal study by assessing levels of stress and depression during the COVID-19 pandemic in a sample of adolescents from the San Francisco Bay Area (N=100; 43 male; ages 13-20 years) who had been characterized 4-7 years earlier (M=5.27, SD=0.75 years) with respect to exposure to ELS and symptoms of depression. Results: As expected, severity of ELS predicted levels of depressive symptoms during the pandemic (r(98)=0.25, p=.012), which were higher in females than in males (t(98)=-3.36, p=.001). Importantly, the association between ELS and depression was mediated by adolescents’ reported levels of stress, even after controlling for demographic and other COVID-19-related variables. Conclusions: These findings underscore the importance of monitoring the mental health of vulnerable children and adolescents during this pandemic and targeting perceived stress and isolation in high-risk youth

HyperXite III

Background:   HyperXite is an undergraduate senior design team at the University of California, Irvine competing in the SpaceX Hyperloop Competition III in the Summer of 2018. Our pod will be a 1:2 scale hyperloop pod utilizing an electric motor, eddy current brakes, and a distributed control system to accelerate through a 1-mile vacuum tube reaching a maximum speed of over 300 MPH. Our ongoing goal is to educate and train our members in advanced analysis, design, and manufacturing methods and to collaborate with industry partners and students from many engineering disciplines. Website: hyperxite.co

HyperXite III

Background:   HyperXite is an undergraduate senior design team at the University of California, Irvine competing in the SpaceX Hyperloop Competition III in the Summer of 2018. Our pod will be a 1:2 scale hyperloop pod utilizing an electric motor, eddy current brakes, and a distributed control system to accelerate through a 1-mile vacuum tube reaching a maximum speed of over 300 MPH. Our ongoing goal is to educate and train our members in advanced analysis, design, and manufacturing methods and to collaborate with industry partners and students from many engineering disciplines. Website: hyperxite.co