Browsing by Subject "neonates"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Open Access
    The neurostructural effects of prenatal exposure to methamphetamine in an infant population in the Western Cape
    (2017) Warton, Fleur Louise; Meintjes, Ernesta M; Warton, Christopher M R
    Prenatal methamphetamine exposure is associated with functional and neurostructural alterations, but neuroimaging investigations of these effects in infants are almost non-existent. Studies in neonates permit a degree of separation of drug exposure effects from potential confounders in the postnatal environment. Magnetic resonance imaging (MRI) was used to investigate the neurostructural effects of prenatal methamphetamine exposure on neonates recruited from a Cape Town community. Mothers were recruited during pregnancy and interviewed regarding methamphetamine use. Women in the exposure group used methamphetamine at least twice per month during pregnancy, while control mothers did not use methamphetamine. MRI scans were acquired within the first postnatal month. Anatomical images were processed using FreeSurfer and subcortical and cerebellar structures manually segmented with Freeview. Volumes were regressed with methamphetamine exposure (days/month of pregnancy) and related confounding variables, including total brain volume, gestational age at scan, exposure to cigarette smoking and infant sex. Diffusion data were processed with FSL, and diffusion tensors and tensor parameters determined using AFNI. Probabilistic tractography defined white matter connections between target regions. For the first analysis, five major white matter networks (commissural, and bilateral projection and association networks) were defined between spherical targets. For the second analysis, regions traced in the anatomical study were used as targets. Averaged DTI parameters were then calculated for each connection, and multiple regression analysis determined associations between DTI parameters and methamphetamine exposure at network level and in the individual connections. Methamphetamine exposure was associated with reduced caudate nucleus volume bilaterally, and in the right caudate following adjustment for confounders. Exposure was associated with reduced fractional anisotropy in all major white matter networks, and in individual connections within the limbic meso-cortico-striatal circuit. Exposure was associated with increased radial diffusivity in a subset of these. These results support findings in older children of methamphetamine-induced neurostructural damage, and demonstrate that such effects are already measurable in neonates. Corticostriatal circuit changes may underlie the impaired executive function observed in prenatally exposed children, and suggest a specific mechanism of damage in dopaminergic-related circuits that is consistent with the neurotoxic actions of methamphetamine.
  • Thumbnail Image
    Item
    Open Access
    Reducing neonatal deaths in South Africa - are we there yet and what can be done?
    (Health and Medical Publishing Group, 2012) Velaphi, S; Rhoda, N
    In the year 2000, 189 member countries of the United Nations committed themselves to eight goals towards the development and well-being of their nations. These goals are called Millenium Development Goals (MDGs). The fourth goal (MDG4) aims to reduce the mortality rate in children under the age of 5 years (U5MR) by two thirds between 1990 and 2015. Infants less than 1 month old account for about 40% of deaths of children under the age of 5 years globally.1 Achieving MDG4 will therefore need to include reducing deaths during the neonatal period. The goal of reducing U5MR by two thirds for neonatal deaths in South Africa meant reducing the neonatal mortality rate (NMR) from 21/1 000 live births in 1998 to 7/1 000 by 2015. In order to achieve this, all neonatal deaths need to be scrutinsed by focusing on mortality rates and pathological and health system causes of neonatal deaths. Of paramount importance, however, would be looking at interventions that could impact significantly on reducing these deaths. In this article we discuss the mortality rates in South Africa, the rest of the world and Africa, and discuss causes and interventions that can be implemented to reduce these deaths in South Africa.