18 research outputs found

    A Specific Activity-Based Probe to Monitor Family GH59 Galactosylceramidase, the Enzyme Deficient in Krabbe Disease

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    Galactosylceramidase (GALC) is the lysosomal β-galactosidase responsible for the hydrolysis of galactosylceramide. Inherited deficiency in GALC causes Krabbe disease, a devastating neurological disorder characterized by accumulation of galactosylceramide and its deacylated counterpart, the toxic sphingoid base galactosylsphingosine (psychosine). We report the design and application of a fluorescently tagged activity-based probe (ABP) for the sensitive and specific labeling of active GALC molecules from various species. The probe consists of a β-galactopyranose-configured cyclophellitol-epoxide core, conferring specificity for GALC, equipped with a BODIPY fluorophore at C6 that allows visualization of active enzyme in cells and tissues. Detection of residual GALC in patient fibroblasts holds great promise for laboratory diagnosis of Krabbe disease. We further describe a procedure for in situ imaging of active GALC in murine brain by intra-cerebroventricular infusion of the ABP. In conclusion, this GALC-specific ABP should find broad applications in diagnosis, drug development, and evaluation of therapy for Krabbe disease

    Sex differences in the adult human brain:Evidence from 5216 UK Biobank participants

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    Sex differences in the human brain are of interest for many reasons: for example, there are sex differences in the observed prevalence of psychiatric disorders and in some psychological traits that brain differences might help to explain. We report the largest single-sample study of structural and functional sex differences in the human brain (2750 female, 2466 male participants; mean age 61.7 years, range 44–77 years). Males had higher raw volumes, raw surface areas, and white matter fractional anisotropy; females had higher raw cortical thickness and higher white matter tract complexity. There was considerable distributional overlap between the sexes. Subregional differences were not fully attributable to differences in total volume, total surface area, mean cortical thickness, or height. There was generally greater male variance across the raw structural measures. Functional connectome organization showed stronger connectivity for males in unimodal sensorimotor cortices, and stronger connectivity for females in the default mode network. This large-scale study provides a foundation for attempts to understand the causes and consequences of sex differences in adult brain structure and function

    Investigating the influence of BCG and hepatitis B vaccine on neonatal immune responses

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    © 2020 Lianne CoxNeonatal infectious diseases result in an estimated 40% of neonatal deaths worldwide and contribute significantly to chronic morbidity. Childhood disease-specific immunisation is irrefutably linked to the decline in deaths from targeted infections over the last century. However, neonatal immunisation strategies are limited, in part, due to impairments in their adaptive immune function. Vaccine-induced protection from severe forms of tuberculosis (TB) with the Bacille Calmette-Guerin vaccine (BCG) and perinatally-acquired hepatitis B infection with the hepatitis B vaccine (HBV) are two exceptions, with these vaccines commonly administered to neonates worldwide. Evidence for heterologous (‘non-specific’) effects (NSEs) of various vaccines used in childhood, most notably for BCG, is increasing. This refers to the immunomodulatory capabilities of vaccines to influence immune outcomes beyond inducing protective immunity against the vaccine’s specific targeted disease. There is limited evidence for these effects in neonates, particularly for HBV. The research reported in this thesis aimed to explore the influence of BCG, HBV and concurrent administration of both vaccines at birth on the neonatal immune responses to unrelated antigens compared with unvaccinated babies in a randomised control trial (RCT): The Early Life Vaccine and Immunity Study (ELVIS). Neonatal blood samples from 128 participants, collected seven days after randomisation, were stimulated with various unrelated antigens for 20 hours. Cytokine responses, measured in the supernatants by an enzyme-linked immunosorbent assay (ELISA) method, were analysed using non-parametric statistical tests to determine differences in median responses between the four groups: BCG alone, HBV alone, concurrent BCG and HBV and the unvaccinated control group. I found minimal differences in the median in vitro cytokine responses to all stimulants between the four groups. However, both vaccines independently influenced cytokine-stimulant responses. Effects on responses were strongest for BCG-vaccinated babies, but only decreased interferon gamma (IFN-gamma) responses to the Toll-like receptor (TLR) ligand resiquimod (R848) and monocyte chemoattractant protein-1 (MCP-1) responses to heat-inactivated E. coli were significantly different from controls. Combined vaccines tended to induce similar cytokine-stimulant response patterns as BCG alone, although for some cytokine-stimulant pairs, the BCG-induced effects were mitigated by HBV and vice versa. This study adds to the evidence for NSEs of vaccines in neonates. It is the first study to investigate the influence of HBV immunisation on immune responses to unrelated antigens, finding no statistically significant differences in median cytokine responses compared with controls. The finding that concurrent vaccination with HBV and BCG at birth induced the same cytokine-stimulant response pattern as BCG alone, suggested that cytokine responses to unrelated stimulants are driven by BCG. This is also the first study to show that in neonates concurrent HBV and BCG vaccination at birth weakens the NSEs of BCG for certain cytokine-stimulant pairs. Further research into neonatal vaccine NSEs are warranted. Future studies should explore and further investigate the clinical relevance of certain cytokine-stimulant response signatures identified in my thesis and the mechanism for these observations in neonates. These results will direct research on how we could potentially exploit any beneficial vaccine NSEs to provide protection against infection in the very young

    Cox Models for Ecologic Time-Series Data?

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    Speech Processors for Auditory Prostheses Prepared by

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    II. Intracochlear potentials evoked by electrical stimulation with phase-separated balanced biphasic pulses............................................................................................................................................................4 III. References.............................................................................................................................................2

    Use of a paediatric advice line for parents of infants recruited to a randomised controlled trial

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    Background: This study aims to describe the use of a paediatric advice line (PAL) provided to parents whose infants were recruited to a large randomised controlled trial (RCT), including the number and types of medical concerns addressed, seasonal variability and call outcomes. Additionally, sociodemographic characteristics of the parents and children of those parents who used the PAL are compared with those who did not. Methods: Prospective cohort of 1246 children nested in the Melbourne Infant Study: BCG for Allergy and Infection Reduction (MIS BAIR) RCT. All MIS BAIR participants were offered access to the PAL. Data were collected over the initial 2 years of a 5-year follow-up. Data were analysed using χ2tests, and ORs were calculated using multiple logistic regression. Results: The PAL was used by 230 (18.5%) participants, who made a total of 586 calls during the 2-year study period. The reasons for calling the PAL were dermatological (24%); gastrointestinal (18%); disturbances in feeding, sleeping and crying (14%); respiratory (7%); and developmental/neurological (6%). Analysis revealed that those who used the PAL were more likely to be first-time parents (OR 1.4, 95% CI 1.1 to 1.9) and mothers who hold a university degree (OR 3.3, 95% CI 1.3 to 8.4). PAL costs were minimal and comprised 15 clinicians with paediatric experience. Conclusions: A cost-effective PAL service for clinical trial participants was used appropriately by parents for relatively minor concerns and may have a role in trials to promote participant engagement and reduce demand for other health services.</p
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