Publications by authors named "Benson Ouma"

Background: The relationship of apolipoprotein-E4 (APOE4) to mortality and cognition after severe malaria in children is unknown.

Methods: APOE genotyping was performed in children with cerebral malaria (CM, n = 261), severe malarial anemia (SMA, n = 224) and community children (CC, n = 213). Cognition was assessed over 2-year follow-up.

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Article Synopsis
  • Elevated levels of angiopoietin-2 (Angpt-2) in severe malaria survivors are linked to poorer overall neurocognitive function, particularly in children under five.
  • The study evaluated Ugandan children post-severe malaria using cognitive assessment tools and considered various factors affecting outcomes, such as disease severity and socio-demographics.
  • Results indicated that higher Angpt-2 levels correlated with worse motor, language, and processing skills in younger children, while no significant effects were seen in older children.
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Objectives: Evaluate the relationship between endothelial activation, malaria complications, and long-term cognitive outcomes in severe malaria survivors.

Design: Prospectively cohort study of children with cerebral malaria, severe malarial anemia, or community children.

Setting: Mulago National Referral Hospital in Kampala, Uganda.

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Autoantibodies targeting host antigens contribute to autoimmune disorders, frequently occur during and after infections and have been proposed to contribute to malaria-induced anemia. We measured anti-phosphatidylserine (PS) and anti-DNA antibody levels in 382 Ugandan children prospectively recruited in a study of severe malaria (SM). High antibody levels were defined as antibody levels greater than the mean plus 3 standard deviations of community children (CC).

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Management of patient care and interpretation of research data require evaluation of laboratory results in the context of reference data from populations with known health status to adequately diagnose disease or make a physiological assessment. Few studies have addressed the diversity of lymphocyte subsets in rural and urban Ugandan populations. Here, 663 healthy blood bank donors from semi-urban centers of Kampala consented to participate in a study to define lymphocyte reference ranges.

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Background And Objective: HIV-1 subtype A is the second most prevalent subtype globally and is associated with reduced viral load, higher CD4 absolute counts, and slower disease progression. To study the possible role of T cells associated with better outcome, we examined CD4 and CD8 T-cell responses against HIV-1 and cytomegalovirus (CMV) in Ugandans infected with subtype A HIV-1.

Methods: T-cell responses were investigated using flow cytometry and novel subtype A variant inclusive peptide (VIP) sets designed for this evaluation.

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To better understand the nature of B cell dysfunctions in subjects infected with HIV-1 subtype A, a rural cohort of 50 treatment-naïve Ugandan patients chronically infected with HIV-1 subtype A was studied, and the relationship between B cell depletion and HIV disease was assessed. B cell absolute counts were found to be significantly lower in HIV-1+ patients, when compared to community matched negative controls (p<0.0001).

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Human immunodeficiency virus type 1 (HIV-1) vaccine and natural history studies are critically dependent on the ability to isolate, cryopreserve, and thaw peripheral blood mononuclear cell (PBMC) samples with a high level of quality and reproducibility. Here we characterize the yield, viability, phenotype, and function of PBMC from HIV-1-infected and uninfected Ugandans and describe measures to ascertain reproducibility and sample quality at the sites that perform cryopreservation. We have developed a comprehensive internal quality control program to monitor processing, including components of method validation.

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Background And Objective: Natural killer (NK) cells most likely contribute toward limiting HIV-1 replication, and investigation into their function throughout the course of infection is therefore important. We here aimed to determine the state of the NK cell compartment in Ugandans with untreated HIV-1 clade A or D infection in comparison with matched uninfected controls.

Methods And Results: The function and phenotype of NK cells were investigated using 10-color flow cytometry.

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Background: Clinical trials are increasingly being conducted internationally. In order to ensure enrollment of healthy participants and proper safety evaluation of vaccine candidates, established reference intervals for clinical tests are required in the target population.

Methodology/principal Findings: We report a reference range study conducted in Ugandan adult blood bank donors establishing reference intervals for hematology and clinical chemistry parameters.

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A phase I randomized, double blind, placebo-controlled trial to assess the immunogenicity of a multiclade HIV-1 DNA plasmid vaccine was conducted in 31 HIV-1-negative Ugandans. Following immunization with DNA at 0, 1, and 2 months, the frequency of HIV-specific immune responses was assessed up to 10 months using a standard chromium release assay (CRA), lymphoproliferative assay (LPA), and antibody dependent cell-mediated cytotoxicity assay (ADCC). Seven of 15 (47%) vaccinees demonstrated CTL activity using the CRA to HIV-1 Env B with responses observed 1 month following the second vaccination and as late as 7 months following complete immunization.

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The use of rapid tests for human immunodeficiency virus (HIV) has become standard in HIV testing algorithms employed in resource-limited settings. We report an extensive HIV rapid test validation study conducted among Ugandan blood bank donors at low risk for HIV infection. The operational characteristics of four readily available commercial HIV rapid test kits were first determined with 940 donor samples and were used to select a serial testing algorithm.

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