1,651 research outputs found

    Paediatric hypertension in South Africa: An underestimated problem calling for action.

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    Hypertension is a major global health problem and the most prominent risk factor for cardiovascular diseases, which disproportionately affect low- and middle-income countries (LMICs). According to a recent report from the Word Health Organization/Strategic Advisory Group of Experts (WHO-SAGE) group, almost half of the South African (SA) adult population is living with hypertension. Although the condition occurs less frequently in children than in adults, evidence now supports the concept that adult essential hypertension has its roots in childhood. A systematic review reports that the prevalence of hypertension in SA children ranges from 7.5% to 22.3%. One in five children aged 5 years is hypertensive (≥95th percentile for age, height and sex), and 60% of children with elevated blood pressure (BP) (>90th percentile for age, height and sex) maintain that status into early adulthood. In addition, there are distinct BP trajectories set early in childhood that are mainly driven by patterns of early life growth and socioeconomic environment. We seek to raise awareness of paediatric hypertension, its risk factors and its consequences, and highlight the importance of action, which can inform early detection and intervention strategies in the context of an increasing burden of cardiovascular disease in SA

    Even transient rapid infancy weight gain is associated with higher BMI in young adults and earlier menarche.

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    BACKGROUND: Early postnatal rapid 'catch-up' weight gain has been consistently associated with subsequent higher obesity risk and earlier pubertal development. In many low- and middle-income countries, infancy catch-up weight gain is transient and often followed by growth faltering. We explored the hypothesis that even transient catch-up weight gain during infancy is associated with later obesity risk and earlier puberty. METHODS: A total of 2352 (1151 male, 1201 female) black South African children in the birth to twenty prospective birth cohort study (Johannesburg-Soweto) underwent serial measurements of body size and composition from birth to 18 years of age. At the age of 18 years, whole-body fat mass and fat-free mass were determined using dual-energy X-ray absorptiometry. Pubertal development was assessed by the research team between ages 9 and 10 years, and it was recorded annually from the age of 11 years using a validated self-assessment protocol. RESULTS: Catch-up weight gain from birth to the age of 1 year, despite being followed by growth faltering between ages 1 and 2 years, was associated with greater mid-upper arm circumference (P=0.04) and skinfold thickness (P=0.048) at 8 years of age, and with higher weight (P<0.001) and body mass index (P=0.001) at 18 years of age after adjustment for sex, age, smoking during pregnancy, birth order, gestational age, formula-milk feeding and household socio-economic status. Infancy catch-up weight gain was also associated with younger age at menarche in girls (P<0.001). This association persisted after adjustment for smoking during pregnancy, birth order, gestational age, formula-milk feeding and household socio-economic status (P=0.005). CONCLUSION: Transient catch-up weight gain from birth to the age of 1 year among children born in a low-income area of South Africa was associated with earlier menarche and greater adiposity in early adulthood. This observation suggests that modifiable determinants of rapid infancy weight gain may be targeted in order to prevent later obesity and consequences of earlier puberty in girls.We are grateful to all study participants, their families and research assistants. Birth to twenty has been supported by The Wellcome Trust, Human Sciences Research Council, Medical Research Council, University of the Witwatersrand, the South African-Netherlands Programme on Alternative Development and the Anglo American Chairman’s Fund.This is the author accepted manuscript. The final version is available via NPG at http://www.nature.com/ijo/journal/vaop/ncurrent/full/ijo201525a.html

    Stringy Stability of Charged Dilaton Black Holes with Flat Event Horizon

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    Electrically charged black holes with flat event horizon in anti-de Sitter space have received much attention due to various applications in Anti-de Sitter/Conformal Field Theory (AdS/CFT) correspondence, from modeling the behavior of quark-gluon plasma to superconductor. Crucial to the physics on the dual field theory is the fact that when embedded in string theory, black holes in the bulk may become vulnerable to instability caused by brane pair-production. Since dilaton arises naturally in the context of string theory, we study the effect of coupling dilaton to Maxwell field on the stability of flat charged AdS black holes. In particular, we study the stability of Gao-Zhang black holes, which are locally asymptotically anti-de Sitter. We find that for dilaton coupling parameter α\alpha > 1, flat black holes are stable against brane pair production, however for 0 < α\alpha < 1, the black holes eventually become unstable as the amount of electrical charges is increased. Such instability however, behaves somewhat differently from that of flat Reissner-Nordstr\"om black holes. In addition, we prove that the Seiberg-Witten action of charged dilaton AdS black hole of Gao-Zhang type with flat event horizon (at least in 5-dimension) is always logarithmically divergent at infinity for finite values of α\alpha, and is finite and positive in the case α\alpha tends to infinity . We also comment on the robustness of our result for other charged dilaton black holes that are not of Gao-Zhang type.Comment: Fixed some confusions regarding whether part of the discussions concern electrically charged hole or magnetically charged one. No changes to the result

    Broken rotational symmetry in the pseudogap phase of a high-Tc superconductor

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    The nature of the pseudogap phase is a central problem in the quest to understand high-Tc cuprate superconductors. A fundamental question is what symmetries are broken when that phase sets in below a temperature T*. There is evidence from both polarized neutron diffraction and polar Kerr effect measurements that time- reversal symmetry is broken, but at temperatures that differ significantly. Broken rotational symmetry was detected by both resistivity and inelastic neutron scattering at low doping and by scanning tunnelling spectroscopy at low temperature, but with no clear connection to T*. Here we report the observation of a large in-plane anisotropy of the Nernst effect in YBa2Cu3Oy that sets in precisely at T*, throughout the doping phase diagram. We show that the CuO chains of the orthorhombic lattice are not responsible for this anisotropy, which is therefore an intrinsic property of the CuO2 planes. We conclude that the pseudogap phase is an electronic state which strongly breaks four-fold rotational symmetry. This narrows the range of possible states considerably, pointing to stripe or nematic orders.Comment: Published version. Journal reference and DOI adde

    Splenic tuberculosis presenting as pyrexia of unknown origin

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    We report a case of a previously healthy 38-year old lady who presented with prolonged fever and hepatosplenomegaly. Intensive investigations were performed for pyrexia of unknown origin which revealed negative. CT scan of the abdomen showed multiple hypodense lesions which did not respond to broad-spectrum antibiotics. Percutaneous biopsy of the splenic lesion revealed granuloma formation and Langhan's giant cells suggestive of TB. She responded well with anti- TB medication but required extended treatment duration of 24 months due to persistence of the splenic lesion on repeated CT scans. This case illustrates a very rare clinical entity of isolated splenic TB with a therapeutic dilemma following incomplete resolution, despite prolonged treatment

    The beta-Secretase Substrate Seizure 6-Like Protein (SEZ6L) Controls Motor Functions in Mice

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    The membrane protein seizure 6–like (SEZ6L) is a neuronal substrate of the Alzheimer’s disease protease BACE1, and little is known about its physiological function in the nervous system. Here, we show that SEZ6L constitutive knockout mice display motor phenotypes in adulthood, including changes in gait and decreased motor coordination. Additionally, SEZ6L knockout mice displayed increased anxiety-like behaviour, although spatial learning and memory in the Morris water maze were normal. Analysis of the gross anatomy and proteome of the adult SEZ6L knockout cerebellum did not reveal any major differences compared to wild type, indicating that lack of SEZ6L in other regions of the nervous system may contribute to the phenotypes observed. In summary, our study establishes physiological functions for SEZ6L in regulating motor coordination and curbing anxiety-related behaviour, indicating that aberrant SEZ6L function in the human nervous system may contribute to movement disorders and neuropsychiatric diseases

    Pediatrics

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    OBJECTIVESTo describe the prevalence and secular trends of high weight-for-length among infants (ages, 3\u201323 months) in the biennial US Department of Agriculture Women, Infants, and Children Program and Participants Characteristic (WIC-PC) Survey from 2000 through 2014 (n = 16 927 120).METHODSWeight-for-length was considered to be \u201chigh\u201d if it was 652 SDs above the sex-and age-specific median in the World Health Organization growth standards. Poisson regression was used to calculate adjusted prevalence ratios.RESULTSThe overall prevalence of high weight-for-length increased from 13.4% in 2000 to 14.5% in 2004, remained constant until 2010, and then decreased by >2 percentage points (to 12.3%) through 2014. The prevalence of high weight-for-length was associated with sex (higher among boys), race-ethnicity (highest among American Indians/Alaskan Natives), and with both age (positive) and family income (inverse). The secular trends, however, were fairly similar within categories of these variables. From 2010 to 2014, the prevalence of high weight-for-length decreased in 40 states and 3 (of 5) US territories, with the largest decreases seen in Puerto Rico ( 129 percentage points) and Kentucky ( 127 percentage points), and the largest increase (+2 percentage points) seen in West Virginia.CONCLUSIONSAlthough the current results cannot be considered representative of infants in the populations, the prevalence of a high weight-for-length has decreased among infants in WIC-PC since 2010. These decreases were similar across categories of most characteristics, but there were substantial differences across jurisdictions, possibly reflecting differences in policy and local programs that target maternal and infant health.20162018-01-01T00:00:00ZCC999999/Intramural CDC HHS/United States27965380PMC5359001777

    Using consecutive Rapid Participatory Appraisal studies to assess, facilitate and evaluate health and social change in community settings

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    BACKGROUND: To investigate how a relatively socio-economically deprived community's needs have changed over time, assess which recommendations from an earlier assessment were implemented and sustained, and consider whether serial Rapid Participatory Appraisal is an effective health research tool that can promote community development and has utility in assessing longitudinal change. METHODS: Rapid Participatory Appraisal involves communities in identifying and challenging their own health-related needs. Information on ten health and social aspects was collated from existing documentation, neighbourhood observations, and interviews with a range of residents and key informants, providing a composite picture of the community's structure, needs and services. RESULTS: The perceived needs after 10 years encompassed a wide construct of health, principally the living environment, housing, and lack of finance. Most identified upstream determinants of health rather than specific medical conditions as primary concerns. After the initial Rapid Participatory Appraisal many interviewees took the recommendations forward, working to promote a healthier environment and advocate for local resources. Interventions requiring support from outwith the community were largely not sustained. CONCLUSION: Rapid Participatory Appraisal proved valuable in assessing long-term change. The community's continuing needs were identified, but they could not facilitate and sustain change without the strategic support of key regional and national agencies. Many repeatedly voiced concerns lay outwith local control: local needs assessment must be supported at higher levels to be effective

    Mid-infrared plasmons in scaled graphene nanostructures

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    Plasmonics takes advantage of the collective response of electrons to electromagnetic waves, enabling dramatic scaling of optical devices beyond the diffraction limit. Here, we demonstrate the mid-infrared (4 to 15 microns) plasmons in deeply scaled graphene nanostructures down to 50 nm, more than 100 times smaller than the on-resonance light wavelength in free space. We reveal, for the first time, the crucial damping channels of graphene plasmons via its intrinsic optical phonons and scattering from the edges. A plasmon lifetime of 20 femto-seconds and smaller is observed, when damping through the emission of an optical phonon is allowed. Furthermore, the surface polar phonons in SiO2 substrate underneath the graphene nanostructures lead to a significantly modified plasmon dispersion and damping, in contrast to a non-polar diamond-like-carbon (DLC) substrate. Much reduced damping is realized when the plasmon resonance frequencies are close to the polar phonon frequencies. Our study paves the way for applications of graphene in plasmonic waveguides, modulators and detectors in an unprecedentedly broad wavelength range from sub-terahertz to mid-infrared.Comment: submitte

    Matrix metalloproteinase-9 activity and a downregulated Hedgehog pathway impair blood-brain barrier function in an <i>in vitro</i> model of CNS tuberculosis

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    Central nervous system tuberculosis (CNS TB) has a high mortality and morbidity associated with severe inflammation. The blood-brain barrier (BBB) protects the brain from inflammation but the mechanisms causing BBB damage in CNS TB are uncharacterized. We demonstrate that Mycobacterium tuberculosis (Mtb) causes breakdown of type IV collagen and decreases tight junction protein (TJP) expression in a co-culture model of the BBB. This increases permeability, surface expression of endothelial adhesion molecules and leukocyte transmigration. TJP breakdown was driven by Mtb-dependent secretion of matrix metalloproteinase (MMP)-9. TJP expression is regulated by Sonic hedgehog (Shh) through transcription factor Gli-1. In our model, the hedgehog pathway was downregulated by Mtb-stimulation, but Shh levels in astrocytes were unchanged. However, Scube2, a glycoprotein regulating astrocyte Shh release was decreased, inhibiting Shh delivery to brain endothelial cells. Activation of the hedgehog pathway by addition of a Smoothened agonist or by addition of exogenous Shh, or neutralizing MMP-9 activity, decreased permeability and increased TJP expression in the Mtb-stimulated BBB co-cultures. In summary, the BBB is disrupted by downregulation of the Shh pathway and breakdown of TJPs, secondary to increased MMP-9 activity which suggests that these pathways are potential novel targets for host directed therapy in CNS TB
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