Prevalence Of Malaria And Glucose-6-Phosphate Dehydrogenase Deficiency In Malaria-Endemic Southwestern Uganda: Implications For Primaquine Use

Abstract Introduction: Malaria transmission in Uganda is remarkably heterogeneous, and declines in prevalence have not been uniform. Previous surveys in southwestern Uganda have shown declines in parasite prevalence from 2004 to 2010. As malaria transmission continues to decline in southwestern Uganda, aggressive strategies, such as the addition of primaquine (PQ) to artemisinin-combination therapies (ACTs), are being considered in low transmission settings. Despite the potential benefit of PQ in reducing transmission, concerns over its safety and efficacy have hampered its deployment. In particular, those with glucose-6-phosphate dehydrogenase (G6PD) deficiency are at a higher risk of hemolytic toxicity. Methods: To better assess how primaquine may impact upon southwestern Uganda, we conducted a cross sectional survey among 631 children under five years of age sampled from districts previously characterized as low (Mbarara), intermediate (Bushenyi), and high (Isingiro) transmission intensities. Blood samples were collected via capillary fingerprick to determine the current status of malaria control and the prevalence of G6PD deficiency. Parasite prevalence was determined using (1) a combined Plasmodium HRP-2/LDH rapid diagnostic test (RDT) (SD Bioline Malaria Ag P.f/Pan) and (2) light microscopy. G6PD deficiency was evaluated by: (1) quantitative G6PD deficiency by spectrophotometric assay (Trinity Biotech®), (2) qualitative G6PD deficiency assay by rapid diagnostic test (CareStart™ G6PD RDT), and (3) DNA was isolated to conduct PCR-RFLP analysis to detect the G6PD A- 202A/376G allele. Results: Prevalence of parasitemia was higher by RDT compared to microscopy (6.2% (95% CI: 4.3-8.1) vs. 3.2% (95% CI: 1.8-4.5)). By district, parasitemia prevalence was 1.2% (3/242) in Mbarara, 3.2% (5/157) in Bushenyi, and 5.2% (12/232) in Isingiro. All 20 microscopy positive cases were detected by RDT. Of the 19 cases detected only by RDT, 7 (36.8%) reported having been treated for malaria within the past month. Notably, of the 20 microscopy positive children, 50% (10/20) were infected with P. falciparum, 40% (8/20) with P. malariae, and the remaining 2 children were P. vivax and P. ovale mono-infections. Knowledge, attitudes, and practice regarding malaria prevention were also assessed, revealing a high proportion of households reporting bednet use (91.6%), but only a small fraction of households participating in indoor residual spraying (0.8%). The prevalence of mild G6PD deficiency (defined as 10-60% of normal activity) was 13.8% (95% CI: 11.1-16.5) as compared to 8.6% (95% CI: 6.4-10.8) by RDT. No participants in our study exhibited severe G6PD deficiency (\u3c10% enzyme activity). Of the 577/631 children considered normal by RDT, 37 were mildly deficient by quantitative assay. Of the 54 children found to be G6PD deficient by RDT, 4 were quantitatively normal. Performance characteristics of the CareStart™ G6PD RDT as compared with the Trinity Biotech® assay revealed low/moderate sensitivity and high specificity (57.5% and 99.3%, respectively). The currently recommended qualitative G6PD assay, the fluorescent spot test (FST), defines deficiency as 10% to 30% of normal G6PD activity. When compared to FST, the sensitivity of CareStart™ G6PD RDT increased to 94.7%, while specificity slightly decreased (94.1%). We found a lack of correlation between genotypic and phenotypic assays. The sensitivity and specificity of the quantitative enzymatic assay to detect the G202A mutation was 29.8% and 87.8%. Conclusion: Our preliminary findings indicate continued strides toward malaria control over the past 10 years in southwestern Uganda. Most notably, our survey reveals a striking shift in species prevalence in this region of Uganda, with nearly 50% of asymptomatic children infected with non-falciparum species. Furthermore, our results strongly suggest the need for better qualitative screening methods evaluating both the phenotype and genotype of G6PD deficiency

Uterine contractions in rodent models and humans

Aberrant uterine contractions can lead to preterm birth and other labour complications and are a significant cause of maternal morbidity and mortality. To investigate the mechanisms underlying dysfunctional uterine contractions, researchers have used experimentally tractable small animal models. However, biological differences between humans and rodents change how researchers select their animal model and interpret their results. Here, we provide a general review of studies of uterine excitation and contractions in mice, rats, guinea pigs, and humans, in an effort to introduce new researchers to the field and help in the design and interpretation of experiments in rodent models

Electrogenic transport and K(+) ion channel expression by the human endolymphatic sac epithelium.

The endolymphatic sac (ES) is a cystic organ that is a part of the inner ear and is connected to the cochlea and vestibule. The ES is thought to be involved in inner ear ion homeostasis and fluid volume regulation for the maintenance of hearing and balance function. Many ion channels, transporters, and exchangers have been identified in the ES luminal epithelium, mainly in animal studies, but there has been no functional study investigating ion transport using human ES tissue. We designed the first functional experiments on electrogenic transport in human ES and investigated the contribution of K(+) channels in the electrogenic transport, which has been rarely identified, even in animal studies, using electrophysiological/pharmacological and molecular biological methods. As a result, we identified functional and molecular evidence for the essential participation of K(+) channels in the electrogenic transport of human ES epithelium. The identified K(+) channels involved in the electrogenic transport were KCNN2, KCNJ14, KCNK2, and KCNK6, and the K(+) transports via those channels are thought to play an important role in the maintenance of the unique ionic milieu of the inner ear fluid

DNA-binding motif and target genes of the imprinted transcription factor PEG3

The Peg3 gene is expressed only from the paternally inherited allele located on proximal mouse chromosome 7. The PEG3 protein encoded by this imprinted gene is predicted to bind DNA based on its multiple zinc finger motifs and nuclear localization. In the current study, we demonstrated PEG3\u27s DNA-binding ability by characterizing its binding motif and target genes. We successfully identified target regions bound by PEG3 from mouse brain extracts using chromatin immunoprecipitation analysis. PEG3 was demonstrated to bind these candidate regions through the consensus DNA-binding motif AGTnnCnnnTGGCT. In vitro promoter assays established that PEG3 controls the expression of a given gene through this motif. Consistent with these observations, the transcriptional levels of a subset of the target genes are also affected in a mutant mouse model with reduced levels of PEG3 protein. Overall, these results confirm PEG3 as a DNA-binding protein controlling specific target genes that are involved in distinct cellular functions. © 2012

Pharmacological chaperones for the oxytocin receptor increase oxytocin responsiveness in myometrial cells

Oxytocin is a potent uterotonic agent administered to nearly all patients during childbirth in the United States. Inadequate oxytocin response can necessitate Cesarean delivery or lead to uterine atony and postpartum hemorrhage. Thus, it may be clinically useful to identify patients at risk for poor oxytocin response and develop strategies to sensitize the uterus to oxytocin. Previously, we showed that the V281M variant in the oxytocin receptor (OXTR) gene impairs OXTR trafficking to the cell surface, leading to a decreased oxytocin response in cells. Here, we sought to identify pharmacological chaperones that increased oxytocin response in cells expressing WT or V281M OXTR. We screened nine small-molecule agonists and antagonists of the oxytocin/vasopressin receptor family and identified two, SR49059 and L371,257, that restored both OXTR trafficking and oxytocin response in HEK293T cells transfected with V281M OXTR. In hTERT-immortalized human myometrial cells, which endogenously express WT OXTR, treatment with SR49059 and L371,257 increased the amount of OXTR on the cell surface by two- to fourfold. Furthermore, SR49059 and L371,257 increased the endogenous oxytocin response in hTERT-immortalized human myometrial cells by 35% and induced robust oxytocin responses in primary myometrial cells obtained from patients at the time of Cesarean section. If future studies demonstrate that these pharmacological chaperones or related compounds function similarly in vivo, we propose that they could potentially be used to enhance clinical response to oxytocin

Long-term persistence of piscine orthoreovirus-1 (PRV-1) infection during the pre-smolt stages of Atlantic salmon in freshwater

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Naturally occurring genetic variants in the oxytocin receptor alter receptor signaling profiles

The hormone oxytocin is commonly administered during childbirth to initiate and strengthen uterine contractions and prevent postpartum hemorrhage. However, patients have wide variation in the oxytocin dose required for a clinical response. To begin to uncover the mechanisms underlying this variability, we screened the 11 most prevalent missense genetic variants in the oxytocin receptor

Marked reduction in antibiotic usage following intensive malaria control in a cohort of Ugandan children.

BACKGROUND: Intensive malaria control may have additional benefits beyond reducing the incidence of symptomatic malaria. We compared antibiotic treatment of children before and after the implementation of highly effective malaria control interventions in Tororo, a historically high transmission area of Uganda. METHODS: Two successive cohorts of children, aged 0.5 to 10 years, were followed from September 2011 to October 2019 in a dedicated study clinic. Universal distribution of long-lasting insecticidal nets was conducted in 2013 and 2017. Sustained indoor residual spraying of insecticide (IRS) was initiated in December 2014. Generalized linear mixed-effects models were used to compare the incidence of antimalarial and antibiotic treatments before and after vector control measures were implemented. RESULTS: Comparing the period prior to the implementation of IRS to the period after IRS had been sustained for 4-5 years, the adjusted incidence of malaria treatments decreased from 2.68 to 0.05 per person-year (incidence rate ratio [IRR] = 0.02, 95% CI 0.01-0.03, p < 0.001), and the adjusted incidence of antibiotic treatments decreased from 4.14 to 1.26 per person-year (IRR = 0.30, 95% CI 0.27-0.34, p < 0.001). The reduction in antibiotic usage was primarily associated with fewer episodes of symptomatic malaria and fewer episodes of fever with sub-microscopic parasitemia, both of which were frequently treated with antibiotics. CONCLUSIONS: In a historically high transmission setting, the implementation of highly effective vector control interventions was followed by a marked reduction in antibiotic treatment of children. This added benefit of malaria control could have important implications for antibiotic prescribing practices, efforts to curtail antimicrobial resistance, and health system costs

Safety of Single-Dose Primaquine in G6PD-Deficient and G6PD-Normal Males in Mali Without Malaria : An Open-Label, Phase 1, Dose-Adjustment Trial

Erratum: The Journal of Infectious Diseases, Volume 217, Issue 7, 1 April 2018, Page 1171, https://doi.org/10.1093/infdis/jiy074Methods: We conducted an open-label, nonrandomized, dose-adjustment trial of the safety of 3 single doses of primaquine in glucose-6-phosphate dehydrogenase (G6PD)-deficient adult males in Mali, followed by an assessment of safety in G6PD-deficient boys aged 11–17 years and those aged 5–10 years, including G6PD-normal control groups. The primary outcome was the greatest within-person percentage drop in hemoglobin concentration within 10 days after treatment. Results: Fifty-one participants were included in analysis. G6PD-deficient adult males received 0.40, 0.45, or 0.50 mg/kg of SLD-PQ. G6PD-deficient boys received 0.40 mg/kg of SLD-PQ. There was no evidence of symptomatic hemolysis, and adverse events considered related to study drug (n = 4) were mild. The mean largest within-person percentage change in hemoglobin level between days 0 and 10 was −9.7% (95% confidence interval [CI], −13.5% to −5.90%) in G6PD-deficient adults receiving 0.50 mg/kg of SLD-PQ, −11.5% (95% CI, −16.1% to −6.96%) in G6PD-deficient boys aged 11–17 years, and −9.61% (95% CI, −7.59% to −13.9%) in G6PD-deficient boys aged 5–10 years. The lowest hemoglobin concentration at any point during the study was 92 g/L. Conclusion: SLD-PQ doses between 0.40 and 0.50 mg/kg were well tolerated in G6PD-deficient males in Mali.Methods: We conducted an open-label, nonrandomized, dose-adjustment trial of the safety of 3 single doses of primaquine in glucose-6-phosphate dehydrogenase (G6PD)-deficient adult males in Mali, followed by an assessment of safety in G6PD-deficient boys aged 11–17 years and those aged 5–10 years, including G6PD-normal control groups. The primary outcome was the greatest within-person percentage drop in hemoglobin concentration within 10 days after treatment. Results: Fifty-one participants were included in analysis. G6PD-deficient adult males received 0.40, 0.45, or 0.50 mg/kg of SLD-PQ. G6PD-deficient boys received 0.40 mg/kg of SLD-PQ. There was no evidence of symptomatic hemolysis, and adverse events considered related to study drug (n = 4) were mild. The mean largest within-person percentage change in hemoglobin level between days 0 and 10 was −9.7% (95% confidence interval [CI], −13.5% to −5.90%) in G6PD-deficient adults receiving 0.50 mg/kg of SLD-PQ, −11.5% (95% CI, −16.1% to −6.96%) in G6PD-deficient boys aged 11–17 years, and −9.61% (95% CI, −7.59% to −13.9%) in G6PD-deficient boys aged 5–10 years. The lowest hemoglobin concentration at any point during the study was 92 g/L. Conclusion: SLD-PQ doses between 0.40 and 0.50 mg/kg were well tolerated in G6PD-deficient males in Mali.Peer reviewe