30 research outputs found

    Pregnancy-related interventions in mothers at risk for gestational diabetes in Asian India and low and middle-income countries (PRIMORDIAL study): protocol for a randomised controlled trial.

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    INTRODUCTION: Lifestyle modification is the mainstay of gestational diabetes mellitus (GDM) prevention. However, clinical trials evaluating the safety and efficacy of diet or physical activity (PA) in low-income and middle-income settings such as Africa and India are lacking. This trial aims to evaluate the efficacy of yoghurt consumption and increased PA (daily walking) in reducing GDM incidence in high-risk pregnant women. METHODS AND ANALYSIS: The study is a 2×2 factorial, open-labelled, multicentre randomised controlled trial to be conducted in Vellore, South India and The Gambia, West Africa. 'High-risk' pregnant women (n=1856) aged ≥18 years and ≤16 weeks of gestational age, with at least one risk factor for developing GDM, will be randomised to either (1) yoghurt (2) PA (3) yoghurt +PA or (4) standard antenatal care. Participants will be followed until 32 weeks of gestation with total active intervention lasting for a minimum of 16 weeks. The primary endpoint is GDM incidence at 26-28 weeks diagnosed using International Association of the Diabetes and Pregnancy Study Groups criteria or elevated fasting glucose (≥5.1 mmol/L) at 32 weeks. Secondary endpoints include absolute values of fasting plasma glucose concentration at 32 weeks gestation, maternal blood pressure, gestational weight gain, intrapartum and neonatal outcomes. Analysis will be both by intention to treat and per-protocol. Continuous outcome measurements will be analysed using multiple linear regression and binary variables by logistic regression. ETHICS AND DISSEMINATION: The study is approved by Oxford Tropical Research Ethics Committee (44-18), ethics committees of the Christian Medical College, Vellore (IRB 11367) and MRCG Scientific Coordinating Committee (SCC 1645) and The Gambia Government/MRCG joint ethics committee (L2020.E15). Findings of the study will be published in peer-reviewed scientific journals and presented in conferences. TRIAL REGISTRATION NUMBER: ISRCTN18467720

    An Action-Oriented AI Policy Toolkit for Technology Audits by Community Advocates and Activists

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    Motivated by the extensive documented disparate harms of artificial intelligence (AI), many recent practitioner-facing reflective tools have been created to promote responsible AI development. However, the use of such tools internally by technology development firms addresses responsible AI as an issue of closed-door compliance rather than a matter of public concern. Recent advocate and activist efforts intervene in AI as a public policy problem, inciting a growing number of cities to pass bans or other ordinances on AI and surveillance technologies. In support of this broader ecology of political actors, we present a set of reflective tools intended to increase public participation in technology advocacy for AI policy action. To this end, the Algorithmic Equity Toolkit (the AEKit) provides a practical policy-facing definition of AI, a flowchart for assessing technologies against that definition, a worksheet for decomposing AI systems into constituent parts, and a list of probing questions that can be posed to vendors, policy-makers, or government agencies. The AEKit carries an action-orientation towards political encounters between community groups in the public and their representatives, opening up the work of AI reflection and remediation to multiple points of intervention. Unlike current reflective tools available to practitioners, our toolkit carries with it a politics of community participation and activism

    Immunization with Radiation-Attenuated Plasmodium berghei Sporozoites Induces Liver cCD8α+DC that Activate CD8+T Cells against Liver-Stage Malaria

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    Immunization with radiation (γ)-attenuated Plasmodia sporozoites (γ-spz) confers sterile and long-lasting immunity against malaria liver-stage infection. In the P. berghei γ-spz model, protection is linked to liver CD8+ T cells that express an effector/memory (TEM) phenotype, (CD44hiCD45RBloCD62Llo ), and produce IFN-γ. However, neither the antigen presenting cells (APC) that activate these CD8+ TEM cells nor the site of their induction have been fully investigated. Because conventional (c)CD8α+ DC (a subset of CD11c+ DC) are considered the major inducers of CD8+ T cells, in this study we focused primarily on cCD8α+ DC from livers of mice immunized with Pb γ-spz and asked whether the cCD8α+ DC might be involved in the activation of CD8+ TEM cells. We demonstrate that multiple exposures of mice to Pb γ-spz lead to a progressive and nearly concurrent accumulation in the liver but not the spleen of both the CD11c+NK1.1− DC and CD8+ TEM cells. Upon adoptive transfer, liver CD11c+NK1.1− DC from Pb γ-spz-immunized mice induced protective immunity against sporozoite challenge. Moreover, in an in vitro system, liver cCD8α+ DC induced naïve CD8+ T cells to express the CD8+ TEM phenotype and to secrete IFN-γ. The in vitro induction of functional CD8+ TEM cells by cCD8α+ DC was inhibited by anti-MHC class I and anti-IL-12 mAbs. These data suggest that liver cCD8α+ DC present liver-stage antigens to activate CD8+ TEM cells, the pre-eminent effectors against pre-erythrocytic malaria. These results provide important implications towards a design of anti-malaria vaccines

    Intense and Mild First Epidemic Wave of Coronavirus Disease, The Gambia.

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    The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic is evolving differently in Africa than in other regions. Africa has lower SARS-CoV-2 transmission rates and milder clinical manifestations. Detailed SARS-CoV-2 epidemiologic data are needed in Africa. We used publicly available data to calculate SARS-CoV-2 infections per 1,000 persons in The Gambia. We evaluated transmission rates among 1,366 employees of the Medical Research Council Unit The Gambia (MRCG), where systematic surveillance of symptomatic cases and contact tracing were implemented. By September 30, 2020, The Gambia had identified 3,579 SARS-CoV-2 cases, including 115 deaths; 67% of cases were identified in August. Among infections, MRCG staff accounted for 191 cases; all were asymptomatic or mild. The cumulative incidence rate among nonclinical MRCG staff was 124 infections/1,000 persons, which is >80-fold higher than estimates of diagnosed cases among the population. Systematic surveillance and seroepidemiologic surveys are needed to clarify the extent of SARS-CoV-2 transmission in Africa

    Human Primary Macrophages Derived In Vitro from Circulating Monocytes Comprise Adherent and Non-Adherent Subsets with Differential Expression of Siglec-1 and CD4 and Permissiveness to HIV-1 Infection

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    Macrophages are a major target for human immunodeficiency virus type 1 (HIV-1) infection. However, macrophages are largely heterogeneous and may exhibit differences in permissiveness to HIV-1 infection. This study highlights the interplay of macrophage heterogeneity in HIV-1 pathogenesis. We show that monocyte-derived macrophages (MDMs) could be divided into two distinct subsets: CD14+Siglec-1hiCD4+ (non-adherent MDM) and CD14+Siglec-1LoCD4− (adherent MDM). The CD14+Siglec-1hiCD4+MDM subset represented the smaller proportion in the macrophage pool, and varied among different donors. Fractionation and subsequent exposure of the two MDM subsets to HIV-1 revealed opposite outcomes in terms of HIV-1 capture and infection. Although the CD14+Siglec-1hiCD4+MDM captured significantly more HIV-1, infection was significantly higher in the CD14+Siglec-1LoCD4−MDM subset. Thus, CD14+Siglec-1hiCD4+MDM were less permissive to infection. Depletion of CD14+Siglec-1hiCD4+MDM or a decrease in their percentage, resulted in increased infection of MDM, suggestive of a capacity of these cells to capture and sequester HIV-1 in an environment that hinders its infectivity. Increased expression of innate restriction factors and cytokine genes were observed in the non-adherent CD14+Siglec-1hiCD4+MDM, both before and after HIV-1 infection, compared to the adherent CD14+Siglec-1LoCD4−MDM. We speculate that the differential expression of gene expression profiles in the two macrophage subsets may provide an explanation for the differences observed in HIV-1 infectivity

    Tracking Human Immunodeficiency Virus-1 Infection in the Humanized DRAG Mouse Model

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    Humanized mice are emerging as an alternative model system to well-established non-human primate (NHP) models for studying human immunodeficiency virus (HIV)-1 biology and pathogenesis. Although both NHP and humanized mice have their own strengths and could never truly reflect the complex human immune system and biology, there are several advantages of using the humanized mice in terms of using primary HIV-1 for infection instead of simian immunodeficiency virus or chimera simian/HIV. Several different types of humanized mice have been developed with varying levels of reconstitution of human CD45+ cells. In this study, we utilized humanized Rag1KO.IL2RγcKO.NOD mice expressing HLA class II (DR4) molecule (DRAG mice) infused with HLA-matched hematopoietic stem cells from umbilical cord blood to study early events after HIV-1 infection, since the mucosal tissues of these mice are highly enriched for human lymphocytes and express the receptors and coreceptors needed for HIV-1 entry. We examined the various tissues on days 4, 7, 14, and 21 after an intravaginal administration of a single dose of purified primary HIV-1. Plasma HIV-1 RNA was detected as early as day 7, with 100% of the animals becoming plasma RNA positive by day 21 post-infection. Single cells were isolated from lymph nodes, bone marrow, spleen, gut, female reproductive tissue, and brain and analyzed for gag RNA and strong stop DNA by quantitative (RT)-PCR. Our data demonstrated the presence of HIV-1 viral RNA and DNA in all of the tissues examined and that the virus was replication competent and spread rapidly. Bone marrow, gut, and lymph nodes were viral RNA positive by day 4 post-infection, while other tissues and plasma became positive typically between 7 and 14 days post-infection. Interestingly, the brain was the last tissue to become HIV-1 viral RNA and DNA positive by day 21 post-infection. These data support the notion that humanized DRAG mice could serve as an excellent model for studying the trafficking of HIV-1 to the various tissues, identification of cells harboring the virus, and thus could serve as a model system for HIV-1 pathogenesis and reservoir studies

    Genetically Attenuated \u3ci\u3ePlasmodium berghei\u3c/i\u3e Liver Stages Induce Sterile Protracted Protection That Is Mediated by Major Histocompatibility Complex Class I–Dependent Interferon-\u3ci\u3ey\u3c/i\u3e–Producing CD8\u3csup\u3e+\u3c/sup\u3e T Cells

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    At present, radiation-attenuated plasmodia sporozoites (y-spz) is the only vaccine that induces sterile and lasting protection in malaria-naive humans and laboratory rodents. However, g-spz are not without risks. For example, the heterogeneity of the y-spz could explain occasional breakthrough infections. To avoid this possibility, we constructed a double-knockout P. berghei parasite by removing 2 genes, UIS3 and UIS4, that are up-regulated in infective spz.We evaluated the double-knockout Pbuis3(-)/4(-) parasites for protective efficacy and the contribution of CD8+ T cells to protection. Pbuis3(-)/4(-) spz induced sterile and protracted protection in C57BL/6 mice. Protection was linked to CD8+ T cells, given that mice deficient in β2m were not protected. Pbuis3(-)/4(-) spz–immune CD8+ T cells consisted of effector/memory phenotypes and produced interferon-y. On the basis of these observations, we propose that the development of genetically attenuated P. falciparum parasites is warranted for tests in clinical trials as a pre-erythrocytic stage vaccine candidate

    Concealed pregnancy as an act of care, A qualitative analysis of motivations for concealing and non-disclosure of early pregnancy in The Gambia

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    BackgroundA barrier to achieving first trimester antenatal care (ANC) attendance in many countries has been the widespread cultural practice of not discussing pregnancies in the early stages. Motivations for concealing pregnancy bear further study, as the interventions necessary to encourage early ANC attendance may be more complicated than targeting infrastructural barriers to ANC attendance such as transportation, time, and cost.MethodsFive focus groups with a total of 30 married, pregnant women were conducted to assess the feasibility of conducting a randomised controlled trial to evaluate the effectiveness of early initiation of physical activity and/or yoghurt consumption in reducing Gestational Diabetes Mellitus in pregnant women in The Gambia. Focus group transcripts were coded through a thematic analysis approach, assessing themes as they arose in relation to failure to attend early ANC.ResultsTwo reasons for the concealment of pregnancies in the first trimester or ahead of a pregnancy’s obvious visibility to others were given by focus group participants. These were ‘pregnancy outside of marriage’ and ‘evil spirits and miscarriage.’ Concealment on both grounds was motivated through specific worries and fears. In the case of a pregnancy outside of marriage, this was worry over social stigma and shame. Evil spirits were widely considered to be a cause of early miscarriage, and as such, women may choose to conceal their pregnancies in the early stages as a form of protection.ConclusionWomen’s lived experiences of evil spirits have been under-explored in qualitative health research as they relate specifically to women’s access to early antenatal care. Better understanding of how such sprits are experienced and why some women perceive themselves as vulnerable to related spiritual attacks may help healthcare workers or community health workers to identify in a timely manner the women most likely to fear such situations and spirits and subsequently conceal their pregnancies

    CD11c<sup>+</sup>NK1.1<sup>−</sup> DC are constitutively present in the spleens of naïve mice but do not substantially increase following immunization.

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    <p>(A) CD11c<sup>+</sup>NK1.1<sup>−</sup>DC in <i>Pb</i>γ−spz-immune splenic MNC were identified according to the procedure described for HMNC in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0005075#pone-0005075-g001" target="_blank">Fig 1</a>. After exclusion of T cells, CD11c<sup>+</sup> cells were segregated into CD11c<sup>+</sup>NK1.1<sup>+</sup> and CD11c<sup>+</sup>NK1.1<sup>−</sup> populations. Splenic mononuclear cells were isolated from individual mice before and after prime and boost immunizations with <i>Pb</i>γ−spz or uninfected mosquito debris (sham). Cells were stained with a cocktail of mAbs and NK1.1<sup>−</sup> DC and CD8<sup>+</sup> T<sub>EM</sub> cells were identified by flow cytometry. (B) Panels show representative contour plots of DC in the spleens of naïve mice and in spleens of mice 6 days after either the 1°, 2° and 3° immunizations and in sham-immunized mice 6 days after the 3° immunization. The percentages of the CD11c<sup>+</sup>NK1.1<sup>−</sup> DC in relation to the total SMNC/spleen for each representative mouse are indicated in each panel. (C) The results show the mean percentage ±SD of CD11c<sup>+</sup>NK1.1<sup>−</sup> DC in total spleens of naïve mice, <i>Pb</i> γ−spz-immunized mice at day 6 after each immunization and in sham-immunized mice at day 6 after the 3° immunization. (D) Panels show representative contour plots of CD8<sup>+</sup> T<sub>CM</sub> cells and CD8<sup>+</sup> T<sub>EM</sub> cells in the spleens of naïve mice as well as of <i>Pb</i> γ−spz-immunized mice and sham-immunized mice at the same time-points described in (B). The numbers indicate the percentages of the T<sub>CM</sub> and T<sub>EM</sub> cells in the gated splenic CD3<sup>+</sup>CD8<sup>+</sup> T cell population. (E) The results show the mean percentage ±SD of CD8<sup>+</sup>T<sub>EM</sub> in the gated splenic CD3<sup>+</sup>CD8<sup>+</sup> T cell population of naïve and immunized mice at day 6 after each immunization. Contour plots and bar graphs are representative of three individual mice per group in three independent experiments.</p
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