Browsing by Author "Namazzi, Ruth"

Now showing 1 - 7 of 7
  • Thumbnail Image
    Item
    Autoantibody levels are associated with acute kidney injury, anemia and post-discharge morbidity and mortality in Ugandan children with severe malaria
    (Nature Research, 2019-10-17) Rivera-Correa, Juan; Conroy, Andrea L.; Opoka, Robert O.; Batte, Anthony; Namazzi, Ruth; Ouma, Benson; Bangirana, Paul; Idro, Richard; Schwaderer, Andrew L.; John, Chandy C.; Rodriguez, Ana; Pediatrics, School of Medicine
    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). We observed increases in median levels of anti-PS and anti-DNA antibodies in children with SM compared to CC (p < 0.0001 for both). Children with severe malarial anemia were more likely to have high anti-PS antibodies than children with cerebral malaria (16.4% vs. 7.4%), p = 0.02. Increases in anti-PS and anti-DNA antibodies were associated with decreased hemoglobin (p < 0.05). A one-unit increase in anti-DNA antibodies was associated with a 2.99 (95% CI, 1.68, 5.31) increase odds of acute kidney injury (AKI) (p < 0.0001). Elevated anti-PS and anti-DNA antibodies were associated with post-discharge mortality (p = 0.031 and p = 0.042, respectively). Children with high anti-PS antibodies were more likely to have multiple hospital readmissions compared to children with normal anti-PS antibody levels (p < 0.05). SM is associated with increased autoantibodies against PS and DNA. Autoantibodies were associated with anemia, AKI, post-discharge mortality, and hospital readmission.
  • Thumbnail Image
    Item
    Clinical Comparison of Retinopathy-Positive and Retinopathy-Negative Cerebral Malaria
    (American Society of Tropical Medicine and Hygiene, 2017-05) Villaverde, Chandler; Namazzi, Ruth; Shabani, Estela; Opoka, Robert O.; John, Chandy C.; Pediatrics, School of Medicine
    AbstractCerebral malaria (CM) is a severe and often lethal complication of falciparum malaria. A classic malaria retinopathy is seen in some (retinopathy-positive [RP]) children but not others (retinopathy-negative [RN]), and is associated with increased parasite sequestration. It is unclear whether RN CM is a severe nonmalarial illness with incidental parasitemia or a less severe form of the same malarial illness as RP CM. Understanding the clinical differences between RP and RN CM may help shed light on the pathophysiology of malarial retinopathy. We compared clinical history, physical examination, laboratory findings, and outcomes of RP (N = 167) and RN (N = 87) children admitted to Mulago Hospital, Kampala, Uganda. Compared with RN children, RP children presented with a longer history of illness, as well as physical examination and laboratory findings indicative of more severe disease and organ damage. The hospital course of RP children was complicated by longer coma duration and a greater transfusion burden than RN children. Mortality did not differ significantly between RP and RN children (14.4% versus 8.0%, P = 0.14). Further, severity of retinal hemorrhage correlated with the majority of variables that differed between RP and RN children. The data suggest that RP and RN CM may reflect the spectrum of illness in CM, and that RN CM could be an earlier, less severe form of disease.
  • Thumbnail Image
    Item
    Dynamic modulation of spleen germinal center reactions by gut bacteria during Plasmodium infection
    (Cell Press, 2021-05-11) Mandal, Rabindra K.; Denny, Joshua E.; Namazzi, Ruth; Opoka, Robert O.; Datta, Dibyadyuti; John, Chandy C.; Schmidt, Nathan W.; Pediatrics, School of Medicine
    Gut microbiota educate the local and distal immune system in early life to imprint long-term immunological outcomes while maintaining the capacity to dynamically modulate the local mucosal immune system throughout life. It is unknown whether gut microbiota provide signals that dynamically regulate distal immune responses following an extra-gastrointestinal infection. We show here that gut bacteria composition correlated with the severity of malaria in children. Using the murine model of malaria, we demonstrate that parasite burden and spleen germinal center reactions are malleable to dynamic cues provided by gut bacteria. Whereas antibiotic-induced changes in gut bacteria have been associated with immunopathology or impairment of immunity, the data demonstrate that antibiotic-induced changes in gut bacteria can enhance immunity to Plasmodium. This effect is not universal but depends on baseline gut bacteria composition. These data demonstrate the dynamic communications that exist among gut bacteria, the gut-distal immune system, and control of Plasmodium infection.
  • Thumbnail Image
    Item
    Lack of mortality in 22 children with sickle cell anemia and severe malarial anemia
    (Wiley, 2018-01) Opoka, Robert O.; Bangirana, Paul; Idro, Richard; Shabani, Estela; Namazzi, Ruth; John, Chandy C.; Pediatrics, School of Medicine
    Retrospective studies suggest that there is high mortality in children with sickle cell anemia (SCA) and severe malaria. We assessed mortality in Ugandan children with severe malarial anemia (SMA, n = 232) or cerebral malaria (CM, n = 267) by sickle cell hemoglobin genotype. Admission and 2‐year follow‐up mortality did not differ among children with SMA who had homozygous form of sickle cell hemoglobin (HbSS) versus normal form of adult hemoglobin (admission, 0/22, 0%, vs. 1/208, 0.5%; follow‐up, 1/22, 4.5%; 7/207, 3.4%, respectively; all P > 0.6). The single child with CM and HbSS survived. The study findings highlight the need for large prospective studies of malaria‐related mortality in children with SCA.
  • Thumbnail Image
    Item
    Methods to estimate baseline creatinine and define acute kidney injury in lean Ugandan children with severe malaria: a prospective cohort study
    (BMC, 2020-09-29) Batte, Anthony; Starr, Michelle C.; Schwaderer, Andrew L.; Opoka, Robert O.; Namazzi, Ruth; Phelps Nishiguchi, Erika S.; Ssenkusu, John M.; John, Chandy C.; Conroy, Andrea L.; Pediatrics, School of Medicine
    Background Acute kidney injury (AKI) is increasingly recognized as a consequential clinical complication in children with severe malaria. However, approaches to estimate baseline creatinine (bSCr) are not standardized in this unique patient population. Prior to wide-spread utilization, bSCr estimation methods need to be evaluated in many populations, particularly in children from low-income countries. Methods We evaluated six methods to estimate bSCr in Ugandan children aged 6 months to 12 years of age in two cohorts of children with severe malaria (n = 1078) and healthy community children (n = 289). Using isotope dilution mass spectrometry (IDMS)-traceable creatinine measures from community children, we evaluated the bias, accuracy and precision of estimating bSCr using height-dependent and height-independent estimated glomerular filtration (eGFR) equations to back-calculate bSCr or estimating bSCr directly using published or population-specific norms. Results We compared methods to estimate bSCr in healthy community children against the IDMS-traceable SCr measure. The Pottel-age based equation, assuming a normal GFR of 120 mL/min per 1.73m2, was the more accurate method with minimal bias when compared to the Schwartz height-based equation. Using the different bSCr estimates, we demonstrated the prevalence of KDIGO-defined AKI in children with severe malaria ranged from 15.6–43.4%. The lowest estimate was derived using population upper levels of normal and the highest estimate was derived using the mean GFR of the community children (137 mL/min per 1.73m2) to back-calculate the bSCr. Irrespective of approach, AKI was strongly associated with mortality with a step-wise increase in mortality across AKI stages (p < 0.0001 for all). AKI defined using the Pottel-age based equation to estimate bSCr showed the strongest relationship with mortality with a risk ratio of 5.13 (95% CI 3.03–8.68) adjusting for child age and sex. Conclusions We recommend using height-independent age-based approaches to estimate bSCr in hospitalized children in sub-Saharan Africa due to challenges in accurate height measurements and undernutrition which may impact bSCr estimates. In this population the Pottel-age based GFR estimating equation obtained comparable bSCr estimates to population-based estimates in healthy children.
  • Thumbnail Image
    Item
    Retinopathy-Positive Cerebral Malaria Is Associated With Greater Inflammation, Blood-Brain Barrier Breakdown, and Neuronal Damage Than Retinopathy-Negative Cerebral Malaria
    (Oxford University Press, 2020-11-10) Villaverde, Chandler; Namazzi, Ruth; Shabani, Estela; Park, Gregory S.; Datta, Dibyadyuti; Hanisch, Benjamin; Opoka, Robert O.; John, Chandy C.; Pediatrics, School of Medicine
    Background: Our prior study findings suggest that Plasmodium falciparum is the cause of disease in both malaria retinopathy-positive (RP) and most retinopathy-negative (RN) cerebral malaria (CM), and that absence of retinopathy and decreased disease severity in RN CM may be due to shorter duration of illness, lower parasite biomass, and decreased var gene expression in RN compared to RP CM. In the present study, we assessed the pathophysiology of RP and RN CM. Methods: We compared markers of systemic and central nervous system inflammation, oxidative stress, neuronal injury, systemic endothelial activation, angiogenesis, and platelet activation in Ugandan children with RP (n = 167) or RN (n = 87) CM. Results: RP children had higher plasma C-reactive protein (P = .013), ferritin and erythropoietin (both P < .001) levels, an elevated cerebrospinal fluid (CSF):plasma albumin ratio (P < .001), and higher CSF tau protein levels (P = .049) than RN children. Levels of plasma and CSF proinflammatory and anti-inflammatory cytokines and oxidative stress markers did not differ between RP and RN children. RN children had higher plasma levels of endothelin 1 (P = .003), platelet-derived growth factor (P = .012), and platelet factor 4 (P = .034). Conclusions: RP and RN CM may represent different phases of CM. RN CM may be driven by early vasospasm and platelet activation, whereas the more advanced RP CM is associated with greater inflammation, increased erythropoietic drive, blood-brain barrier breakdown, and neuronal injury, each of which may contribute to greater disease severity.
  • Thumbnail Image
    Item
    Zinc for Infection Prevention in Sickle Cell Anemia (ZIPS): study protocol for a randomized placebo-controlled trial in Ugandan children with sickle cell anemia
    (BioMed Central, 2019-07-26) Datta, Dibyadyuti; Namazzi, Ruth; Conroy, Andrea L.; Cusick, Sarah E.; Hume, Heather A.; Tagoola, Abner; Ware, Russell E.; Opoka, Robert O.; John, Chandy C.; Pediatrics, School of Medicine
    BACKGROUND: Sickle cell anemia (SCA) is the most common inherited hemoglobinopathy worldwide. Infection is a major cause of illness and death in children with SCA, especially in sub-Saharan Africa where an estimated 50-90% of affected children die before their fifth birthday. Interventions to reduce the incidence and severity of infections are needed urgently. A high proportion of adults and children with SCA are zinc-deficient, and zinc deficiency leads to impaired immunity and an increased risk of infection. Zinc supplementation has been shown to decrease the risk of infection in adolescents and adults, but there are no data on the effectiveness of zinc for prevention of infection in children < 5 years of age with SCA. METHODS/DESIGN: The study will be a randomized, placebo-controlled, double-blind clinical trial in which 250 Ugandan children 1.00-4.99 years of age with SCA will receive daily zinc supplementation (10 mg oral dispersible tablet) or identical placebo for 12 months. DISCUSSION: If this trial shows a reduction in severe or invasive infection incidence, it would be the basis for a multi-site, multi-country clinical trial to assess real-world safety and efficacy of zinc in African children with SCA. Since zinc is safe, inexpensive, and easy to administer, this trial has the potential to improve the health of hundreds of thousands of African children with SCA through reduction of infection-related morbidity and mortality.