126 results on '"Bright Adu"'
Search Results
52. Association of Immunoglobulin G3 Hinge Region Length Polymorphism With Cerebral Malaria in Ghanaian Children
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Tracy Sarkodie-Addo, Kwadwo A. Kusi, Michael Theisen, Daniel Dodoo, Fareed K. N. Arthur, Eric Kyei-Baafour, and Bright Adu
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medicine.medical_specialty ,biology ,Plasmodium falciparum ,Malaria, Cerebral ,Antibodies, Protozoan ,Logistic regression ,medicine.disease ,biology.organism_classification ,Ghana ,Allotype ,Infectious Diseases ,Polymorphism (computer science) ,Cerebral Malaria ,Immunoglobulin G ,parasitic diseases ,Epidemiology ,Immunology ,medicine ,Humans ,Immunology and Allergy ,Malaria, Falciparum ,Allele ,Child ,Malaria - Abstract
Cerebral malaria (CM) may cause death or long-term neurological damage in children, and several host genetic risk factors have been reported. Malaria-specific immunoglobulin (Ig) G3 antibodies are crucial to human immune response against malaria. The hinge region of IgG3 exhibits length polymorphism (with long [L], medium [M], and short [S] alleles), which may influence its functionality. We studied IgG3 hinge region length polymorphisms in 136 Ghanaian children with malaria. Using logistic regression models, we found that children with the recessive MM allotype encoding medium IgG3 hinge region length had an increased risk of CM (adjusted odds ratio, 6.67 [95% confidence interval,1.30–34.32]; P=.004) . This has implications for future epidemiological studies on CM.
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- 2021
53. Spatiotemporal variation in risk of Shigella infection in childhood: a global risk mapping and prediction model using individual participant data
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Hamada S. Badr, Josh M. Colston, Nhat-Lan H. Nguyen, Yen Ting Chen, Syed Asad Ali, Ajit Rayamajhi, Syed M. Satter, Nguyen Van Trang, Daniel Eibach, Ralf Krumkamp, Jürgen May, Ayola Akim Adegnika, Gédéon Prince Manouana, Peter Gottfried Kremsner, Roma Chilengi, Luiza Hatyoka, Amanda K. Debes, Jerome Ateudjieu, Abu S. G. Faruque, M. Jahangir Hossain, Suman Kanungo, Karen L. Kotloff, Inácio Mandomando, M. Imran Nisar, Richard Omore, Samba O. Sow, Anita K. M. Zaidi, Nathalie Lambrecht, Bright Adu, Nicola Page, James A. Platts-Mills, Cesar Mavacala Freitas, Tuula Pelkonen, Per Ashorn, Kenneth Maleta, Tahmeed Ahmed, Pascal Bessong, Zulfiqar A. Bhutta, Carl Mason, Estomih Mduma, Maribel P. Olortegui, Pablo Peñataro Yori, Aldo A. M. Lima, Gagandeep Kang, Jean Humphrey, Robert Ntozini, Andrew J. Prendergast, Kazuhisa Okada, Warawan Wongboot, Nina Langeland, Sabrina J. Moyo, James Gaensbauer, Mario Melgar, Matthew Freeman, Anna N. Chard, Vonethalom Thongpaseuth, Eric Houpt, Benjamin F. Zaitchik, and Margaret N. Kosek
- Abstract
BackgroundDiarrheal disease remains a leading cause of childhood illness and mortality and Shigella is a major etiological contributor for which a vaccine may soon be available. This study aimed to model the spatiotemporal variation in pediatric Shigella infection and map its predicted prevalence across low- and middle-income countries (LMICs).MethodsIndependent participant data on Shigella positivity in stool samples collected from children aged ≤59 months were sourced from multiple LMIC-based studies. Covariates included household- and subject-level factors ascertained by study investigators and environmental and hydrometeorological variables extracted from various data products at georeferenced child locations. Multivariate models were fitted, and prevalence predictions obtained by syndrome and age stratum.Findings20 studies from 23 countries contributed 66,563 sample results. Age, symptom status, and study design contributed most to model performance followed by temperature, wind speed, relative humidity, and soil moisture. Shigella probability exceeded 20% when both precipitation and soil moisture were above average and had a 43% peak in uncomplicated diarrhea cases at 33°C temperatures, above which it decreased. Improved sanitation and open defecation decreased Shigella odds by 19% and 18% respectively compared to unimproved sanitation.InterpretationThe distribution of Shigella is more sensitive to climatological factors like temperature than previously recognized. Conditions in much of sub-Saharan Africa are particularly propitious for Shigella transmission, though hotspots also occur in South and Central America, the Ganges–Brahmaputra Delta, and New Guinea. These findings can inform prioritization of populations for future vaccine trials and campaigns.FundingNASA 16-GEO16-0047; NIH-NIAID 1R03AI151564-01; BMGF OPP1066146.
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- 2022
54. Plasmodium falciparumcoinfection is associated with improved IgE and IgG3 response against hookworm antigens
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Samuel A. Sakyi, Michael D. Wilson, Bright Adu, Stephen Opoku, Antwi Brewoo, Amma Larbi, Emmanuel K. Baafour, Samuel K. Tchum, Roland O. Saahene, Wilfred Aniagyei, Christian Sewor, David Courtin, Michael Cappello, Ben Gyan, and Benjamin Amoani
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General Medicine - Published
- 2022
55. Genomic analysis of SARS-CoV-2 reveals local viral evolution in Ghana
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Linda Boatemaa, Evangeline Obodai, Gordon A. Awandare, Ivy A. Asante, George B. Kyei, Isaac Darko Otchere, Miriam Eshun, Joyce M. Ngoi, Collins M. Morang’a, Joseph H.K. Bonney, Abraham K. Anang, Nicaise Tuikue Ndam, Dominic S. Y. Amuzu, Augustina K. Arjarquah, Lucas Amenga-Etego, Erasmus N. Kotey, Frederick Tei-Maya, William Ampofo, John Kofi Odoom, Evelyn Y. Bonney, Peter K. Quashie, Bright Adu, Vanessa Magnusen, Yaw Bediako, Selassie Kumordjie, and Joe Kimanthi Mutungi
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0301 basic medicine ,novel coronavirus ,Sequence assembly ,Genomics ,Genome, Viral ,Biology ,Ghana ,Genome ,General Biochemistry, Genetics and Molecular Biology ,Evolution, Molecular ,03 medical and health sciences ,0302 clinical medicine ,Phylogenetics ,evolution ,genomics ,Humans ,030212 general & internal medicine ,Clade ,Phylogeny ,Original Research ,Genetics ,Phylogenetic tree ,SARS-CoV-2 ,COVID-19 ,Amplicon ,3. Good health ,030104 developmental biology ,Viral evolution - Abstract
The confirmed case fatality rate for the coronavirus disease 2019 (COVID-19) in Ghana has dropped from a peak of 2% in March to be consistently below 1% since May 2020. Globally, case fatality rates have been linked to the strains/clades of circulating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) within a specific country. Here we present 46 whole genomes of SARS-CoV-2 circulating in Ghana, from two separate sequencing batches: 15 isolates from the early epidemic (March 12–April 1 2020) and 31 from later time-points ( 25–27 May 2020). Sequencing was carried out on an Illumina MiSeq system following an amplicon-based enrichment for SARS-CoV-2 cDNA. After genome assembly and quality control processes, phylogenetic analysis showed that the first batch of 15 genomes clustered into five clades: 19A, 19B, 20A, 20B, and 20C, whereas the second batch of 31 genomes clustered to only three clades 19B, 20A, and 20B. The imported cases (6/46) mapped to circulating viruses in their countries of origin, namely, India, Hungary, Norway, the United Kingdom, and the United States of America. All genomes mapped to the original Wuhan strain with high similarity (99.5–99.8%). All imported strains mapped to the European superclade A, whereas 5/9 locally infected individuals harbored the B4 clade, from the East Asian superclade B. Ghana appears to have 19B and 20B as the two largest circulating clades based on our sequence analyses. In line with global reports, the D614G linked viruses seem to be predominating. Comparison of Ghanaian SARS-CoV-2 genomes with global genomes indicates that Ghanaian strains have not diverged significantly from circulating strains commonly imported into Africa. The low level of diversity in our genomes may indicate lower levels of transmission, even for D614G viruses, which is consistent with the relatively low levels of infection reported in Ghana.
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- 2020
56. SARS-CoV-2 detection among international air travellers to Ghana during mandatory quarantine
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John Kofi Odoom, James Aboagye, Lawrence Lartey, Joseph Bonney, George B. Kyei, William Ampofo, Mildred A. Adusei-Poku, Ivy A. Asante, Ernest K. Asiedu, Bright Adu, Evangeline Obodai, and Evelyn Y. Bonney
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2019-20 coronavirus outbreak ,Coronavirus disease 2019 (COVID-19) ,business.industry ,SARS-CoV-2 ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Outcome measures ,COVID-19 ,Ghana ,law.invention ,Cross-Sectional Studies ,law ,Environmental health ,Quarantine ,Pandemic ,Medicine ,Humans ,Early phase ,business ,Retrospective Studies - Abstract
Objectives: To determine the prevalence of SARS-CoV-2 detection among international travellers to Ghana during mandatory quarantine. Design: A retrospective cross-sectional study. Setting: Air travellers to Ghana on 21st and 22nd March 2020. Participants: On 21st and 22nd March 2020, a total of 1,030 returning international travellers were mandatorily quarantined in 15 different hotels in Accra and tested for SARS-CoV-2. All of these persons were included in the study. Main outcome measure: Positivity for SARS-CoV-2 by polymerase chain reaction. Results: The initial testing at the beginning of quarantine found 79 (7.7%) individuals to be positive for SARS-CoV- 2. In the exit screening after 12 to 13 days of quarantine, it was discovered that 26 of those who tested negative for SARS-CoV-2 in the initial screening subsequently tested positive. Conclusions: Ghana likely averted an early community spread of COVID-19 through the proactive approach to quarantine international travellers during the early phase of the pandemic. © 2021 Clinical Archives of Communication Disorders. All rights reserved.
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- 2022
57. Data management during COVID-19 outbreak response in Ghana: a reference laboratory perspective on key issues and measures
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Evelyn Y. Bonney, Kwadwo A. Koram, George B. Kyei, Ivy A. Asante, Evangeline Obodai, Helena Lamptey, John Kofi Odoom, Ernest Kenu, William Ampofo, James Aboagye, Mildred A. Adusei-Poku, Joseph Bonney, and Bright Adu
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Coronavirus disease 2019 (COVID-19) ,business.industry ,SARS-CoV-2 ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Data management ,Perspective (graphical) ,COVID-19 ,Turnaround time ,Ghana ,Test (assessment) ,Disease Outbreaks ,Pandemic ,Global health ,Medicine ,Humans ,Operations management ,business ,Laboratories ,Pandemics ,Data Management - Abstract
The COVID-19 pandemic caused by SARS-CoV-2 is an important subject for global health. Ghana experienced lowmoderate transmission of the disease when the first case was detected in March 12, 2020 until the middle of July when the number of cases begun to drop. By August 24, 2020, the country's total number of confirmed cases stood at 43,622, with 263 deaths. By the same time, the Noguchi Memorial Institute for Medical Research (NMIMR) of the University of Ghana, the primary testing centre for COVID-19, had tested 285,501 with 28,878 confirmed cases. Due to database gaps, there were initial challenges with timely reporting and feedback to stakeholders during the peak surveillance period. The gaps resulted from mismatches between samples and their accompanying case investigation forms, samples without case investigation forms and vice versa, huge data entry requirements, and delayed test results. However, a revamp in data management procedures, and systems helped to improve the turnaround time for reporting results to all interested parties and partners. Additionally, inconsistencies such as multiple entries and discrepant patient-sample information were resolved by introducing a barcoding electronic capture system. Here, we describe the main challenges with COVID-19 data management and analysis in the laboratory and recommend measures for improvement. © 2021 Clinical Archives of Communication Disorders. All rights reserved.
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- 2022
58. Evaluating the predictive performance of malaria antibodies and FCGR3B gene polymorphisms on Plasmodium falciparum infection outcome: a prospective cohort study
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Samuel Iddi, Michael Theisen, Daniel Dodoo, Thomas A. Gerds, Bright Adu, and Duah Dwomoh
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Male ,Antibodies, Protozoan ,Ghana ,0302 clinical medicine ,Discrimination ,Longitudinal Studies ,Prospective Studies ,030212 general & internal medicine ,Malaria, Falciparum ,Child ,Apical membrane antigen 1 ,Malaria vaccine ,Incidence ,FCGR3B ,Infectious Diseases ,Area Under Curve ,Child, Preschool ,Calibration ,Female ,Antibody ,Antigenes ,Bootstrap-validation ,Brier score ,lcsh:Arctic medicine. Tropical medicine ,lcsh:RC955-962 ,FCGR3B gene polymorphisms ,Plasmodium falciparum ,030231 tropical medicine ,Biology ,GPI-Linked Proteins ,Antibodies ,lcsh:Infectious and parasitic diseases ,03 medical and health sciences ,Antigen ,parasitic diseases ,medicine ,Humans ,lcsh:RC109-216 ,Polymorphism, Genetic ,Research ,Receptors, IgG ,Infant, Newborn ,Infant ,Apical membrane ,medicine.disease ,biology.organism_classification ,Malaria ,ROC Curve ,Immunology ,biology.protein ,Area under the receiver operating characteristic curve ,Parasitology - Abstract
Background Malaria antigen-specific antibodies and polymorphisms in host receptors involved in antibody functionality have been associated with different outcomes of Plasmodium falciparum infections. Thus, to identify key prospective malaria antigens for vaccine development, there is the need to evaluate the associations between malaria antibodies and antibody dependent host factors with more rigorous statistical methods. In this study, different statistical models were used to evaluate the predictive performance of malaria-specific antibodies and host gene polymorphisms on P. falciparum infection in a longitudinal cohort study involving Ghanaian children. Methods Models with different functional forms were built using known predictors (age, sickle cell status, blood group status, parasite density, and mosquito bed net use) and malaria antigen-specific immunoglobulin (Ig) G and IgG subclasses and FCGR3B polymorphisms shown to mediate antibody-dependent cellular functions. Malaria antigens studied were Merozoite surface proteins (MSP-1 and MSP-3), Glutamate Rich Protein (GLURP)-R0, R2, and the Apical Membrane Antigen (AMA-1). The models were evaluated through visualization and assessment of differences between the Area Under the Receiver Operating Characteristic Curve and Brier Score estimated by suitable internal cross-validation designs. Results This study found that the FCGR3B-c.233C>A genotype and IgG against AMA1 were relatively better compared to the other antibodies and FCGR3B genotypes studied in classifying or predicting malaria risk among children. Conclusions The data supports the P. falciparum, AMA1 as an important malaria vaccine antigen, while FCGR3B-c.233C>A under the additive and dominant models of inheritance could be an important modifier of the effect of malaria protective antibodies.
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- 2020
59. The Plasmodium falciparum circumsporozoite protein produced in Lactococcus lactis is pure and stable
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Swarnendu Kaviraj, Bishwanath Kumar Chourasia, Jordan Plieskatt, Michael Theisen, Judith M. Bolscher, C. Richter King, Koen J. Dechering, Susheel K. Singh, Emily Locke, Vandana Singh, Bright Adu, and Blanca López-Méndez
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0301 basic medicine ,030102 biochemistry & molecular biology ,biology ,Chemistry ,Malaria vaccine ,Immunogenicity ,Lactococcus lactis ,Plasmodium falciparum ,Cell Biology ,biology.organism_classification ,Biochemistry ,In vitro ,law.invention ,Circumsporozoite protein ,03 medical and health sciences ,030104 developmental biology ,law ,Recombinant DNA ,Molecular Biology ,Conformational epitope - Abstract
The Plasmodium falciparum circumsporozoite protein (PfCSP) is a sporozoite surface protein whose role in sporozoite motility and cell invasion has made it the leading candidate for a pre-erythrocytic malaria vaccine. However, production of high yields of soluble recombinant PfCSP, including its extensive NANP and NVDP repeats, has proven problematic. Here, we report on the development and characterization of a secreted, soluble, and stable full-length PfCSP (containing 4 NVDP and 38 NANP repeats) produced in the Lactococcus lactis expression system. The recombinant full-length PfCSP, denoted PfCSP4/38, was produced initially with a histidine tag and purified by a simple two-step procedure. Importantly, the recombinant PfCSP4/38 retained a conformational epitope for antibodies as confirmed by both in vivo and in vitro characterizations. We characterized this complex protein by HPLC, light scattering, MS analysis, differential scanning fluorimetry, CD, SDS-PAGE, and immunoblotting with conformation-dependent and -independent mAbs, which confirmed it to be both pure and soluble. Moreover, we found that the recombinant protein is stable at both frozen and elevated-temperature storage conditions. When we used L. lactis-derived PfCSP4/38 to immunize mice, it elicited high levels of functional antibodies that had the capacity to modify sporozoite motility in vitro We concluded that the reported yield, purity, results of biophysical analyses, and stability of PfCSP4/38 warrant further consideration of using the L. lactis system for the production of circumsporozoite proteins for preclinical and clinical applications in malaria vaccine development.
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- 2020
60. Fcγ receptor IIIB NA1/NA2/SH polymorphisms are associated with malaria susceptibility and antibody levels to P. falciparum merozoite antigens in Beninese children
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Abdou Khadre Dit Jadir Fall, David Courtin, Rafiou Adamou, Sofie Edslev, Anita Hansen, Nadia Domingo, Michael Christiansen, Bright Adu, Jacqueline Milet, André Garcia, Michael Theisen, Florence Migot-Nabias, and Célia Dechavanne
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Inorganic Chemistry ,Organic Chemistry ,General Medicine ,Physical and Theoretical Chemistry ,Molecular Biology ,Spectroscopy ,Catalysis ,Fc gamma receptor ,FcgRIIIB-NA1 ,NA2 ,SH variants ,malaria susceptibility ,antibody response ,Benin ,Computer Science Applications - Abstract
This paper aimed to investigate the influence of polymorphisms in the FCGR2A gene encoding R131H FcgRIIA variants and in the FCGR3B gene (108G > C, 114C > T, 194 A > G, 233C > A, 244 G > A and 316G > A) encoding FcgRIIIB-NA1, -NA2 and -SH variants on malaria susceptibility and antibody responses against P. falciparum merozoite antigens in Beninese children. An active malaria follow-up was conducted in infants from birth to 24 months of age in Allada, Benin. FCGR3B exon 3 was sequenced and FCGR2A exon 4 was genotyped. Antibodies directed to GLURP and MSP3 were quantified by ELISA. Association studies were performed using mixed-effect models. Individual carriage of FCGR3B 194 AA genotype was associated with a high number of malaria infections and a low level of IgG1 against MSP3 and GLURP-R0. High parasitemia and increased malaria infections were observed in infants carrying the FCGR3B*05 108C-114T-194A-233C-244A-316A haplotype. A reduced risk of malaria infections and low parasitemia were related to the carriages of the FCGR3B 108C-114T-194G-233C-244G-316A (FCGR3B*06), FCGR3B 108C-114T-194G-233A-244A-316A (FCGR3B*03 encoding for FcgRIIIB-SH) haplotypes and FCGR3B 297 TT genotype. Our results highlight the impact of FCGR3B polymorphisms on the individual susceptibility to malaria and antibody responses against MSP3 and GLURP in Beninese children.
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- 2022
61. Ruminant-Related Risk Factors are Associated with Shiga Toxin–Producing Escherichia coli Infection in Children in Southern Ghana
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Gloria Folson, Andrew D. Jones, Mark L. Wilson, Ana Baylin, Joseph N. S. Eisenberg, Nathalie J Lambrecht, Dave Bridges, and Bright Adu
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Veterinary medicine ,Salmonella ,Livestock ,Biology ,medicine.disease_cause ,Campylobacter jejuni ,Ghana ,Enteropathogenic Escherichia coli ,Feces ,Virology ,Campylobacter Infections ,medicine ,Animals ,Humans ,Escherichia coli ,Escherichia coli Infections ,Sheep ,Shiga-Toxigenic Escherichia coli ,Transmission (medicine) ,Goats ,Infant ,Odds ratio ,Ruminants ,biology.organism_classification ,Fecal coliform ,Infectious Diseases ,Cross-Sectional Studies ,Logistic Models ,Milk ,Child, Preschool ,Salmonella Infections ,Parasitology ,Cattle ,Chickens ,Research Article - Abstract
Livestock can provide benefits to low-income households, yet may expose children to zoonotic enteropathogens that cause illness and negative long-term health outcomes. The aim of this cross-sectional study was to determine whether livestock-related risk factors, including animal ownership, exposure to animal feces, and consumption of animal-source foods, were associated with bacterial zoonotic enteropathogen infections in children 6–59 months old in Greater Accra, Ghana. Stool samples from 259 children and 156 household chickens were analyzed for atypical enteropathogenic Escherichia coli (aEPEC), Campylobacter jejuni/coli (C. jejuni/coli), Salmonella, and Shiga toxin–producing Escherichia coli (STEC) using quantitative polymerase chain reaction (qPCR). aEPEC, C. jejuni/coli, STEC, and Salmonella were detected in 45.6%, 11.6%, 4.3%, and 0.8% of children’s stool samples, respectively. In adjusted logistic regression models, household ownership of goats or sheep was associated with STEC detection in children (odds ratio [95% confidence interval]: 4.30 [1.32, 14.08]), as were positive detection of STEC in chicken feces (7.85 [2.54, 24.30]) and frequent consumption of fresh cow’s milk (3.03 [1.75, 5.24]). No livestock-related risk factors were associated with aEPEC or C. jejuni/coli infection in children. Our findings suggest that ruminant ownership in southern Ghana may expose children to STEC through household fecal contamination and foodborne routes. The lack of association between livestock risk factors and the more commonly detected pathogens, aEPEC and C. jejuni/coli, warrants further research, particularly to help explain how animal-keeping and sanitation practices affect transmission of fecal pathogens that were highly prevalent in chicken feces.
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- 2021
62. Neutrophils dominate in opsonic phagocytosis of P. falciparum blood-stage merozoites and protect against febrile malaria
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Michael Theisen, Subhash Singh, Sanne Hertegonne, Asier Garcia-Senosiain, Morten Hanefeld Dziegiel, Bright Adu, Ikhlaq Hussain Kana, and Manoj K. Das
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Fever ,QH301-705.5 ,Neutrophils ,Phagocytosis ,Plasmodium falciparum ,Adaptive immunity ,Medicine (miscellaneous) ,General Biochemistry, Genetics and Molecular Biology ,Article ,Antibodies ,parasitic diseases ,medicine ,Biology (General) ,Phagocytic Cell ,Malaria, Falciparum ,Opsonin ,biology ,Merozoites ,biology.organism_classification ,medicine.disease ,In vitro ,Cellular immunity ,Malaria ,Blood stage ,Immunology ,Fc-Gamma Receptor ,Infectious diseases ,General Agricultural and Biological Sciences - Abstract
Antibody-mediated opsonic phagocytosis (OP) of Plasmodium falciparum blood-stage merozoites has been associated with protection against malaria. However, the precise contribution of different peripheral blood phagocytes in the OP mechanism remains unknown. Here, we developed an in vitro OP assay using peripheral blood leukocytes that allowed us to quantify the contribution of each phagocytic cell type in the OP of merozoites. We found that CD14 + +CD16− monocytes were the dominant phagocytic cells at very low antibody levels and Fc gamma receptor (FcγR) IIA plays a key role. At higher antibody levels however, neutrophils were the main phagocytes in the OP of merozoites with FcγRIIIB acting synergistically with FcγRIIA in the process. We found that OP activity by neutrophils was strongly associated with protection against febrile malaria in longitudinal cohort studies performed in Ghana and India. Our results demonstrate that peripheral blood neutrophils are the main phagocytes of P. falciparum blood-stage merozoites., Garcia-Senosiain et al developed an in vitro opsonic phagocytosis (OP) assay using peripheral blood leukocytes that enabled quantification of the contribution of each phagocytic cell type in the OP of Plasmodium falciparum blood-stage merozoites, which have been associated with malaria protection. Using patient samples from Ghana and India, they demonstrate that peripheral blood neutrophils are the main phagocytes of P. falciparum blood-stage merozoites
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- 2021
63. Breadth of Functional Antibodies Is Associated With Plasmodium falciparum Merozoite Phagocytosis and Protection Against Febrile Malaria
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Susheel K. Singh, Subhash C. Singh, Daniel Dodoo, Asier Garcia-Senosiain, Bright Adu, Michael Theisen, and Ikhlaq Hussain Kana
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Male ,0301 basic medicine ,Plasmodium falciparum ,Protozoan Proteins ,Antibodies, Protozoan ,Antigens, Protozoan ,Ghana ,Immunoglobulin G ,03 medical and health sciences ,0302 clinical medicine ,Phagocytosis ,Antigen ,Immunity ,Malaria Vaccines ,parasitic diseases ,medicine ,Humans ,Immunology and Allergy ,Longitudinal Studies ,030212 general & internal medicine ,Malaria, Falciparum ,Child ,biology ,Merozoites ,Malaria vaccine ,Infant ,Acquired immune system ,medicine.disease ,biology.organism_classification ,030104 developmental biology ,Infectious Diseases ,Child, Preschool ,Immunology ,biology.protein ,Female ,Antibody ,Malaria - Abstract
Background The specific targets of functional antibodies against Plasmodium falciparum merozoites remain largely unexplored and, more importantly, their relevance to naturally acquired immunity in longitudinal cohort studies (LCSs) is yet to be tested. Methods Functionality of immunoglobulin G (IgG) antibodies against 24 merozoite antigens was determined at the baseline of an LCS in Ghana using a bead-based opsonic phagocytosis assay (BPA). Antigen-specific IgG3 subclass antibodies were quantified in the same samples by the Luminex multiplex system. Results A wide range of BPA activity was observed across the different antigens. High BPA responses of nMSP3K1, GLURP-R2, MSP23D7, MSP119k, and PfRh2-2030 coupled beads were significantly associated with a higher probability of children not experiencing febrile malaria. Children with high breadth of functional antibodies against these antigens together with cMSP33D7 had a significantly reduced risk of febrile malaria (adjusted hazard ratio, 0.36 [95% confidence interval, .18-.72]; P = .004). Five of the 6 BPA activities significantly (likelihood ratio rest, P ≤ .05) contributed to the protective immunity observed with the IgG3 antibodies. Conclusions The development of BPA allowed profiling of functional antibodies in an LCS. Identification of targets of opsonic phagocytosis may have implications in the development of a subunit malaria vaccine.
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- 2019
64. Impact of IgG response to malaria-specific antigens and immunity against malaria in pre-school children in Ghana. A cluster randomized, placebo-controlled trial
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Fareed K. N. Arthur, Samuel Asamoah Sakyi, Felix Boakye Oppong, Francis Dzabeng, Kwaku Poku-Asante, Thomas Gyan, Benjamin Amoani, Bright Adu, and Samuel Kofi Tchum
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Male ,Physiology ,Placebo-controlled study ,Protozoan Proteins ,Ghana ,Biochemistry ,0302 clinical medicine ,Medical Conditions ,Immune Physiology ,Medicine and Health Sciences ,030212 general & internal medicine ,Enzyme-Linked Immunoassays ,Immune Response ,Protozoans ,Multidisciplinary ,Immune System Proteins ,Nutritional Deficiencies ,Malarial Parasites ,Eukaryota ,Anemia ,Iron deficiency ,Hematology ,Micronutrient ,Child, Preschool ,Medicine ,Female ,Research Article ,medicine.medical_specialty ,Science ,Iron ,030231 tropical medicine ,Immunology ,Antigens, Protozoan ,Placebo ,Research and Analysis Methods ,03 medical and health sciences ,Double-Blind Method ,Antigen Isotypes ,Internal medicine ,parasitic diseases ,medicine ,Parasitic Diseases ,Humans ,Antigens ,Iron Deficiency Anemia ,Immunoassays ,Nutrition ,business.industry ,Organisms ,Infant ,Biology and Life Sciences ,Proteins ,medicine.disease ,Tropical Diseases ,Parasitic Protozoans ,Malaria ,Malnutrition ,Iron-deficiency anemia ,Immunoglobulin G ,Dietary Supplements ,Immunologic Techniques ,Iron Deficiency ,business - Abstract
Background Iron fortification and micronutrient initiatives, specifically, vitamin A, and zinc supplementation are the most cost-effective developmental strategies against malnutrition and health emergencies in pre-school children. Iron-deficiency among pre-school children have been documented, however, studies evaluating the impact of immunoglobulin G (IgG) isotype responses among iron-fortified pre-school children in malaria endemic communities has not been assessed. We evaluated the impact of iron fortification on the IgG responses to GLURP R0, GLURP R2 and MSP3 FVO malaria-specific antigens among pre-school children in malaria endemic areas. Methods This community-based, placebo-controlled, double-blinded, cluster-randomized trial study was conducted in Wenchi Municipal and Tain District of Bono Region. The trial was registered at ClinicalTrials.gov-registered trial (Identifier: NCT01001871). Ethical approval was obtained and informed consent were sought from each participant parents/guardian. For the current objective, 871 children aged 6–35 months were screened, from which 435 children received semi-liquid home-made meals mixed with 12.5 mg of iron daily (intervention group), and 436 received micronutrient powder without iron (placebo group) for 5 months. Standardized clinical and epidemiological questionnaires were administered and blood samples taken to measure IgG responses to GLURP R0, GLURP R2 and MSP3 FVO recombinant antigens using the Afro Immunoassay (AIA) protocol. Results Baseline anthropometry, malaria diagnosis, anaemia and iron status, demographic features and dietary intake were identical among the groups (p > 0.05). After the intervention, there was no significant difference in the IgG response against GLUP R0, GLUP R2 and MSP3 FVO between the iron-containing micronutrient and placebo groups (p > 0.05). The iron-containing micronutrient powder group who were iron-sufficient or iron replete had significantly higher IgG response to GLURP R0 and GLURP R2 compared to iron-deficient and iron-deficiency anaemia in the same group (p < 0.05). The IgG responses to all the three malaria specific antigens were low among children without malaria episode but high among those with two and four episodes due to exposure differences. Conclusion Iron fortification did not influence antibody response against endogenous malaria specific antigens among pre-school children in malaria endemic areas, however, IgG response to malaria specific antigens were high among children with sufficient iron status.
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- 2021
65. Suitability of IgG responses to multiple Plasmodium falciparum antigens as markers of transmission intensity and pattern
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Michael Theisen, Lars Hviid, Régis Wendpayangde Tiendrebeogo, Margaret Kweku, Eric Kyei-Baafour, Belinda Aculley, Fareed K. N. Arthur, Bright Adu, Michael F. Ofori, Kwadwo A. Kusi, Mavis Oppong, Susheel K. Singh, and Abena Fremaah Frempong
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Male ,Plasmodium ,Physiology ,Antibody Response ,Antibodies, Protozoan ,Biochemistry ,Ghana ,law.invention ,Geographical Locations ,Medical Conditions ,Seroepidemiologic Studies ,law ,Immune Physiology ,Medicine and Health Sciences ,Parasite hosting ,Enzyme-Linked Immunoassays ,Malaria, Falciparum ,Child ,Immune Response ,Protozoans ,Immune System Proteins ,Multidisciplinary ,biology ,Malarial Parasites ,Eukaryota ,Transmission (mechanics) ,Child, Preschool ,Medicine ,Female ,Antibody ,medicine.symptom ,Research Article ,Science ,Immunology ,Plasmodium falciparum ,Antigens, Protozoan ,Research and Analysis Methods ,Asymptomatic ,Antibodies ,Antigen ,Parasite Groups ,parasitic diseases ,Parasitic Diseases ,medicine ,Humans ,Seroprevalence ,Immunoassays ,Organisms ,Biology and Life Sciences ,Proteins ,Infant ,Tropical Diseases ,biology.organism_classification ,medicine.disease ,Parasitic Protozoans ,Malaria ,Cross-Sectional Studies ,ROC Curve ,Immunoglobulin G ,People and Places ,Africa ,Immunologic Techniques ,biology.protein ,Parasitology ,Apicomplexa ,Biomarkers - Abstract
Detection of antibody reactivity to appropriate, specific parasite antigens may constitute a sensitive and cost-effective alternative to current tools to monitor malaria transmission across different endemicity settings. This study aimed to determine the suitability of IgG responses to a number of P. falciparum antigens as markers of transmission intensity and pattern. Antibody responses to multiple malaria antigens were determined in 905 participants aged 1–12 years from three districts with low (Keta), medium (Hohoe) and high (Krachi) transmission intensity in the Volta region of Ghana. Blood film microscopy slides and dry blood spots (DBS) were obtained for parasitaemia detection and antibody measurement, respectively. Sera were eluted from DBS and levels of IgG specific for 10 malaria antigens determined by a multiplex assay. Results were compared within and among the districts. Total IgG responses to MSPDBL1, MSPDBLLeucine, MSP2-FC27, RAMA, and PfRh2a and PfRh2b were higher in Krachi than in Hohoe and Keta. Seroprevalence of IgG specific for MSPDBLLeucine, RON4, and PfRh2b were also highest in Krachi. Responses to RALP-1, PfRh2a and PfRh2b were associated with patent but asymptomatic parasitaemia in Keta, while responses to MSPDBL1, MSPDBLLeucine, MSP2-FC27, RAMA, Rh2-2030, and PfRh2b were associated with parasite carriage in Hohoe, but not in Krachi. Using ROC analysis, only PfRh2b was found to predict patent, but asymptomatic, parasitaemia in Keta and Hohoe. Antibody breadth correlated positively with age (r = 0.29, pPfRh2b has potential as a marker of malaria transmission intensity and pattern. This could have implications for malaria control programs and vaccine trials.
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- 2021
66. Extended follow-up of children in a phase2b trial of the GMZ2 malaria vaccine
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Peter G. Kremsner, Sodiomon B. Sirima, Paul Milligan, Fareed K. N. Arthur, Sylvester Dassah, Benjamin Mordmüller, Donnie Mategula, Michael Theisen, Clare Flach, Bright Adu, Peter Bang, Ulysse Ateba Ngoa, Benedicta A. Mensah, Frank Atuguba, and Mark Kaddumukasa
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medicine.medical_specialty ,Plasmodium falciparum ,030231 tropical medicine ,Antigens, Protozoan ,03 medical and health sciences ,0302 clinical medicine ,Rabies vaccine ,Double-Blind Method ,Internal medicine ,Malaria Vaccines ,Clinical endpoint ,medicine ,Humans ,030212 general & internal medicine ,Malaria, Falciparum ,Child ,Adverse effect ,General Veterinary ,General Immunology and Microbiology ,biology ,business.industry ,Malaria vaccine ,Public Health, Environmental and Occupational Health ,biology.organism_classification ,Vaccine efficacy ,medicine.disease ,Confidence interval ,Infectious Diseases ,Molecular Medicine ,business ,Malaria ,Follow-Up Studies ,medicine.drug - Abstract
BACKGROUND: The GMZ2/alum candidate malaria vaccine had an efficacy of 14% (95% confidence interval [CI]: 3.6%, 23%) against clinical malaria over 6 months of follow-up in a phase2b multicentre trial in children 1-5 years of age. Here we report the extended follow up of safety and efficacy over 2 years.METHODS: A total of 1849 (GMZ2 = 926, rabies = 923) children aged 12-60 months were randomized to receive intramuscularly, either 3 doses of 100 μg GMZ2/alum or 3 doses of rabies vaccine as control 28 days apart. The children were followed-up for 24 months for clinical malaria episodes and adverse events. The primary endpoint was documented fever with parasitaemia of at least 5000/μL.RESULTS: There were 2,062 malaria episodes in the GMZ2/alum group and 2,115 in the rabies vaccine group in the intention-to-treat analysis, vaccine efficacy (VE) of 6.5% (95%: CI -1.6%, 14.0%). In children aged 1-2 years at enrolment, VE was 3.6% (95 %CI: -9.1%, 14.8%) in the first year and -4.1% (95 %CI: -18.7%, 87%) in the second year. In children aged 3-5 years at enrolment VE was 19.9% (95 %CI: 7.7%, 30.4%) in the first year and 6.3% (95 %CI: -10.2%, 20.3%) in the second year (interaction by year, P = 0.025, and by age group, P = 0.085). A total of 187 (GMZ2 = 91, rabies = 96) serious adverse events were recorded in 167 individuals over the entire period of the study. There were no GMZ2 vaccine related serious adverse events.CONCLUSIONS: GMZ2/alum was well tolerated. Follow-up over 2 years confirmed a low level of vaccine efficacy with slightly higher efficacy in older children, which suggests GMZ2 may act in concert with naturally acquired immunity.
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- 2021
67. Microbial exposure drives polyclonal expansion of innate γδ T cells immediately after birth
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Lars Steinbrück, Beverly Egyir, Daniel Dodoo, Alina Suzann Fichtner, Jennifer Schöning, Malte Deseke, Sabine Pirr, Peter Ghazal, Inga Sandrock, Dennis Torkornoo, Maike Willers, Immo Prinz, Anneke Wilharm, Bright Adu, Katie L. Flanagan, Anja Bubke, Paul Dickinson, Dorothee Viemann, and Sarina Ravens
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0301 basic medicine ,T cell ,Biology ,Gene Rearrangement, T-Lymphocyte ,03 medical and health sciences ,0302 clinical medicine ,Immune system ,T-Lymphocyte Subsets ,medicine ,Humans ,Longitudinal Studies ,Child ,Gene ,Africa South of the Sahara ,Multidisciplinary ,Bacteria ,T-cell receptor ,Infant, Newborn ,Infant ,Receptors, Antigen, T-Cell, gamma-delta ,Biological Sciences ,Junctional diversity ,Peripheral blood ,Early life ,Europe ,030104 developmental biology ,medicine.anatomical_structure ,Polyclonal antibodies ,Child, Preschool ,Immunology ,biology.protein ,030215 immunology - Abstract
Starting at birth, the immune system of newborns and children encounters and is influenced by environmental challenges. It is still not completely understood how γδ T cells emerge and adapt during early life. Studying the composition of T cell receptors (TCRs) using next-generation sequencing (NGS) in neonates, infants, and children can provide valuable insights into the adaptation of T cell subsets. To investigate how neonatal γδ T cell repertoires are shaped by microbial exposure after birth, we monitored the γ-chain (TRG) and δ-chain (TRD) repertoires of peripheral blood T cells in newborns, infants, and young children from Europe and sub-Saharan Africa. We identified a set of TRG and TRD sequences that were shared by all children from Europe and Africa. These were primarily public clones, characterized by simple rearrangements of Vγ9 and Vδ2 chains with low junctional diversity and usage of non-TRDJ1 gene segments, reminiscent of early ontogenetic subsets of γδ T cells. Further profiling revealed that these innate, public Vγ9Vδ2(+) T cells underwent an immediate TCR-driven polyclonal proliferation within the first 4 wk of life. In contrast, γδ T cells using Vδ1(+) and Vδ3(+) TRD rearrangements did not significantly expand after birth. However, different environmental cues may lead to the observed increase of Vδ1(+) and Vδ3(+) TRD sequences in the majority of African children. In summary, we show how dynamic γδ TCR repertoires develop directly after birth and present important differences among γδ T cell subsets.
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- 2020
68. Impact of Iron Fortification on Anaemia and Iron Deficiency among Pre-school Children Living in Rural Ghana
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Fareed K. N. Arthur, Thomas Gyan, Samuel Asamoah Sakyi, Felix Boakye Oppong, Francis Dzabeng, Benjamin Amoani, Latifatu Alhassan Abubakar, Seeba Amenga-Etego, Kwaku Poku-Asante, Dorcas Atibilla, Samuel Kofi Tchum, Bright Adu, and Emmanuel Arhin
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Male ,Epidemiology ,Organic chemistry ,Ascorbic Acid ,Biochemistry ,Ghana ,Families ,Hemoglobins ,Medical Conditions ,Medicine and Health Sciences ,Medicine ,Vitamin A ,Children ,education.field_of_study ,Multidisciplinary ,biology ,Anemia, Iron-Deficiency ,Nutritional Deficiencies ,Anemia ,Iron deficiency ,Hematology ,Vitamins ,Micronutrient ,Chemistry ,Zinc ,Child, Preschool ,Physical Sciences ,Female ,medicine.drug ,Research Article ,Chemical Elements ,medicine.medical_specialty ,Science ,Iron ,Population ,Iron fortification ,Ferrous Fumarate ,Chemical compounds ,Internal medicine ,Environmental health ,Organic compounds ,Parasitic Diseases ,Humans ,Ferrous Compounds ,education ,Iron Deficiency Anemia ,Nutrition ,Ferritin ,business.industry ,Biology and Life Sciences ,Proteins ,Protein Complexes ,Infant ,medicine.disease ,Ascorbic acid ,Tropical Diseases ,Placebo Effect ,Malaria ,Trace Elements ,Iron-deficiency anemia ,Age Groups ,Medical Risk Factors ,People and Places ,Dietary Supplements ,biology.protein ,Iron Deficiency ,Population Groupings ,Pre school ,business - Abstract
Background Micronutrient interventions, principally vitamin A and zinc supplementation for children, and fortification of foods with iron and iodine, are considered the most cost-effective global development efforts. Multiple micronutrient powder is a mixture of at least iron, zinc and vitamin A used to prevent malnutrition in children and during health emergencies. Micronutrient deficiencies are a universal health burden among young children in developing countries. However, the use of this low cost but sustainable micronutrient powder as an innovative home-fortification approach to control a common nutritional disorder like iron deficiency anaemia among pre-school children living in malaria endemic sub-Saharan Africa is unclear. The aim of our study was to determine the effect of providing long-term continued prophylactic micronutrient powder with iron on the risk of iron deficiency and anaemia among pre-school children living in rural Ghana.Methods This population-based randomized-cluster trial was conducted in the Bono region of Ghana from 3rd April to 6th July 2010. 1958 children were recruited, and 967 randomly assigned to receive prophylactic micronutrient powder with iron and 991 assigned to receive placebo. The trial participants were children aged between 6 to 35 months, identified at home and able to eat semi-solid foods (with or without breast milk). Structured questionnaires were administered, their blood samples were also taken for biochemical analysis. They were randomly assigned to receive daily micronutrient powder without or with iron (12·5 mg) added to complementary meals immediately after enrollment for five months. Each participant also received anti-malaria treated bednet and chemotherapy. Weekly follow up visits were conducted at home or health facility where data on malaria using rapid diagnostic test and hospital admissions were collected. The primary outcome was post supplementation of prophylactic micronutrient powder with iron to mitigate the effects of iron deficiency and anaemia.Results 1958 children were recruited and 967 randomly assigned to receive prophylactic micronutrient powder with iron and 991 assigned to receive placebo. Loss to follow up was 7 % (143), with vital status at 35 months of age reported for 1904 (97.2 %). Anthropometry, anaemia, iron status, demographic characteristics and dietary intakes were similar between the groups at baseline. Baseline haemoglobin level was significantly higher compared to haemoglobin level at endline (p < 0.0001). Though, we recorded an increase in haemoglobin (p = 0.0001) and ferritin (p = 0.0002) levels in the iron group than in the placebo group at the end of the intervention. Soluble transferrin receptor levels were more saturated among children from the iron group compared to placebo group (p = 0.012). Anaemic status in the iron group improved compared to the non-iron group (p = 0.03).Conclusion The risk of childhood morbidity and mortality in rural Ghana is high, mainly due to iron deficiency anaemia. National nutritional policy coupled with the current WHO recommendations are required to support the provision of prophylactic micronutrient powder with iron in order to improve anaemic and iron status among pre-school children in rural Ghana.TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01001871. Registered 27th October 2009, http://www. ClinicalTrials.gov/ NCT01001871
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- 2020
69. Effect of Drug Pressure on Promoting the Emergence of Antimalarial-Resistant Parasites among Pregnant Women in Ghana
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Philippe Deloron, Nicaise Tuikue Ndam, Atikatou Mama, Pascal Houzé, Michael F. Ofori, Romain Coppée, Isabella A. Quakyi, Nathaniel Coleman, Kwadwo A. Kusi, Jérôme Clain, Bernard Tornyigah, Rachida Tahar, Bright Adu, and Abraham K. Anang
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Nonsynonymous substitution ,Drug ,Combination therapy ,media_common.quotation_subject ,Plasmodium falciparum ,030231 tropical medicine ,Drug Resistance ,Protozoan Proteins ,Drug resistance ,Ghana ,Antimalarials ,03 medical and health sciences ,0302 clinical medicine ,Mechanisms of Resistance ,Pregnancy ,Sulfadoxine ,parasitic diseases ,Animals ,Humans ,Medicine ,Parasites ,Pharmacology (medical) ,Malaria, Falciparum ,Artemisinin ,030304 developmental biology ,media_common ,Pharmacology ,0303 health sciences ,biology ,business.industry ,biology.organism_classification ,Virology ,Sulfadoxine/pyrimethamine ,Drug Combinations ,Tetrahydrofolate Dehydrogenase ,Pyrimethamine ,Infectious Diseases ,Pharmaceutical Preparations ,Genetic marker ,Female ,Pregnant Women ,business ,medicine.drug - Abstract
The continuous spread of antimalarial drug resistance is a threat to current chemotherapy efficacy. Therefore, characterizing the genetic diversity of drug resistance markers is needed to follow treatment effectiveness and further update control strategies. Here, we genotyped Plasmodium falciparum resistance gene markers associated with sulfadoxine-pyrimethamine (SP) and artemisinin-based combination therapy (ACT) in isolates from pregnant women in Ghana. The prevalence of the septuple IRN I- A/FG K GS/Tpfdhfr/pfdhps haplotypes, including the pfdhps A581G and A613S/T mutations, was high at delivery among post-SP treatment isolates (18.2%) compared to those of first antenatal care (before initiation of intermittent preventive treatment of malaria in pregnancy with sulfadoxine-pyrimethamine [IPTp-SP]; 6.1%; P = 0.03). Regarding the pfk13 marker gene, two nonsynonymous mutations (N458D and A481C) were detected at positions previously related to artemisinin resistance in isolates from Southeast Asia. These mutations were predicted in silico to alter the stability of the pfk13 propeller-encoding domain. Overall, these findings highlight the need for intensified monitoring and surveillance of additional mutations associated with increased SP resistance as well as emergence of resistance against artemisinin derivatives.
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- 2020
70. Microscopic and Submicroscopic Asymptomatic Plasmodium falciparum Infections in Ghanaian Children and Protection against Febrile Malaria
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Caleb K. Sinclear, Sophia Eyia-Ampah, Michael Theisen, Selassie Kumordjie, Quratul Ain Issahaque, Bright Adu, Tracy Sarkodie-Addo, Eric Kyei-Baafour, Eunice Owusu-Yeboa, and Daniel Dodoo
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0301 basic medicine ,Male ,030231 tropical medicine ,Immunology ,Plasmodium falciparum ,Antibodies, Protozoan ,Parasitemia ,Microbiology ,Asymptomatic ,Ghana ,03 medical and health sciences ,0302 clinical medicine ,parasitic diseases ,medicine ,Humans ,Longitudinal Studies ,Malaria, Falciparum ,Child ,Asymptomatic Infections ,biology ,Transmission (medicine) ,Hazard ratio ,Infant ,medicine.disease ,biology.organism_classification ,030104 developmental biology ,Infectious Diseases ,Child, Preschool ,biology.protein ,Parasitology ,Female ,Disease Susceptibility ,Antibody ,medicine.symptom ,Malaria ,Cohort study - Abstract
Naturally acquired immunity to Plasmodium falciparum malaria is thought to be nonsterile and sustained by persistence of low-level parasitemia. This study assessed the association between baseline microscopic and submicroscopic asymptomatic P. falciparum infections and antimalarial antibody levels and whether these parasitemia modify protective associations between antibody levels and malaria in Ghanaian children. Healthy children (N = 973, aged 0.5 to 12 years) were recruited into a 50-week longitudinal malaria cohort study from January 2016 to January 2017. Baseline asymptomatic parasitemia were determined by microscopy (microscopic parasitemia) and PCR (submicroscopic parasitemia), and antibody levels against crude schizont antigens were measured by enzyme-limited immunosorbent assay (ELISA). Antibody levels, parasite diversity, and risk of malaria in the ensuing transmission season were compared among children who had baseline asymptomatic microscopic or submicroscopic or no P. falciparum infections. Of the 99 asymptomatic baseline infections, 46 (46.5%) were microscopic and 53 (53.5%), submicroscopic. Cox regression analysis adjusting for age group, sex and community found a strong association between both baseline microscopic (hazard ratio [HR] = 0.36, 95% confidence interval [95% CI] = 0.21 to 0.63; P
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- 2020
71. Nuisance Activities of Straw Colored Fruit Bats (Eidolon helvum) on the University of Energy and Natural Resources, Ghana
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Mordecai Opoku Ohemeng, James Agyei-Ohemeng, Francis Boafo Asamoah, and Bright Adu Yeboah
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Geography ,Colored ,biology ,Agroforestry ,Straw ,biology.organism_classification ,Nuisance ,Natural resource ,Eidolon helvum - Published
- 2020
72. Growth and Yield of Taro (Colocasia esculenta (L) Schott.) as Affected by Planting Distance
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L. M. Aboagye, Richard Boampong, Richard Adu Amoah, Eric Osafo Ansah, Samuel Kwasi Boateng, and Bright Adu Gyamfi
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Article Subject ,Agriculture (General) ,Randomized block design ,Sowing ,Corm ,Biology ,Petiole (botany) ,S1-972 ,Colocasia esculenta ,Crop ,Agronomy ,Yield (wine) ,Optimum growth ,Agronomy and Crop Science - Abstract
Taro, Colocasia esculenta (L) Schott., is a staple food for many people in Africa. Despite the numerous importance of the crop, it still remains an underutilized crop in Ghana with little information on many aspects of the crop, especially agronomic practices. This experiment was conducted to identify the effect of planting distance on growth and yield of two promising taro accessions. The experiment was laid out using the split-plot design arranged in Randomized Complete Block Design (RCBD) with three replications in which accessions (BL/SM/80 and BL/SM/16) were used as main plots and three planting distances (1 m × 1 m, 1 m × 0.75 m, and 1 m × 0.5 m) as subplots. Data were recorded on the 4th, 8th, 12th, 16th, 20th, 24th, and 28th week after planting (WAP) for growth parameters while yield data were taken at harvest. The results indicated that plant height (63.4 cm), petiole length (44.0 cm), number of leaves (4.7), leaf length (31.7 cm), and width (20.5 cm) were significantly ( P ≤ 0.05 ) higher in closely spaced plants than widely spaced plants at 4 WAP and 8 WAP for petiole length (70.3 cm) and in the 28th WAP where there was an accession effect on leaf length and number of suckers/plant. The highest corm yield/plant (0.63 kg) and total corm yield/ha (11.7 t/ha) in both accessions were achieved by the medium plant spacing (1 m × 0.75 m) and lower plant spacing (1 m × 0.5 m), respectively. Accession BS/SM/80 recorded the highest total yield/ha of 13.0 t/ha for 1 m × 0.5 m plant spacing. The higher number of suckers (8.1) was recorded by higher spaced plants. From the study, it was seen that growth parameters correlated significantly and positively with yield. It is therefore recommended that farmers in the area and those in similar production areas use a spacing of 1 m × 0.5 m for optimum growth and yield.
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- 2020
73. Individual innovation behavior and firm-level exploration and exploitation: how family firms make the most of their managers
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Viktoria Veider, Kurt Matzler, Andreas Strobl, and Bright Adu Nketia
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Managerial discretion ,0502 economics and business ,05 social sciences ,Sample (statistics) ,Context (language use) ,060301 applied ethics ,06 humanities and the arts ,Business ,0603 philosophy, ethics and religion ,General Business, Management and Accounting ,050203 business & management ,Industrial organization - Abstract
This study investigates the influence of top managers’ individual innovation behavior on firm-level innovation activities, specifically on exploration and exploitation. The influence of individual actions depends on managerial discretion, which is dependent on the ownership context of a business. Thus, this study explores how family ownership moderates the relationships between a top manager’s individual innovation behavior and firm-level exploration and exploitation. Based on a sample of 195 firms, of which 120 are family firms, our findings depict highly significant relationships between managers’ individual innovation behavior and firm-level exploration and exploitation innovation. Furthermore, we find differences regarding these relationships between family firms and their non-family counterparts. We contribute to literature showing that family firms provide a unique context for leveraging a top manager’s individual innovation behavior into firm-level exploration activities.
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- 2018
74. Individual innovation behavior and firm-level exploration and exploitation:How family firms make the most of their managers
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Strobl, Andreas, Matzler, Kurt, Nketia, Bright Adu, Veider, Viktoria, Strobl, Andreas, Matzler, Kurt, Nketia, Bright Adu, and Veider, Viktoria
- Abstract
This study investigates the influence of top managers’ individual innovation behavior on firm-level innovation activities, specifically on exploration and exploitation. The influence of individual actions depends on managerial discretion, which is dependent on the ownership context of a business. Thus, this study explores how family ownership moderates the relationships between a top manager’s individual innovation behavior and firm-level exploration and exploitation. Based on a sample of 195 firms, of which 120 are family firms, our findings depict highly significant relationships between managers’ individual innovation behavior and firm-level exploration and exploitation innovation. Furthermore, we find differences regarding these relationships between family firms and their non-family counterparts. We contribute to literature showing that family firms provide a unique context for leveraging a top manager’s individual innovation behavior into firm-level exploration activities.
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- 2020
75. Governance structures, cash holdings and firm value on the Ghana Stock Exchange
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Bright Adu Bonsu, Yayra Goka, Amoako Kwarteng, Samuel Famiyeh, and Disraeli Asante-Darko
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050208 finance ,Corporate governance ,media_common.quotation_subject ,05 social sciences ,Working capital ,Enterprise value ,Monetary economics ,Market liquidity ,Stock exchange ,Cash ,0502 economics and business ,Business, Management and Accounting (miscellaneous) ,Business ,Capital market ,050203 business & management ,media_common ,Valuation (finance) - Abstract
Purpose There is an existing relationship among shareholders, boards of directors and management of companies. Corporate governance practices of companies are expected to ensure that this relationship maximises the wealth of shareholders. Differences exist among corporate governance of companies listed on the Ghana Stock Exchange. Companies, for purposes of liquidity, hold cash, but cash holdings also add to the cost of financing, according to working capital theories. The study, thus, sought to examine the relationship between corporate governance practices, ownership structure, cash holdings and firm value. Design/methodology/approach The study deployed the seemingly unrelated regression to reduce the problem of multicollinearity resulting from the strong relationship between cash reserves and some control variables. Findings The study found no significant relationship between board size and firm value. Similar findings were also made on the relationship between proportion of non-executive directors on the board and firm value. However, firms audited by the big four audit firms are valued higher by the capital market. Cash holdings of firms negatively affect performance, and this is statistically significant. A positive relationship arises between a firm’s cash holdings and its value as a result of debt financing, even though this is not significant. Originality/value The study is the first of its kind that deploys Tobin’s Q as a measure of firms’ value to reflect investors’ valuation of firms in Ghana. The study is also the first of its kind to test the interactive effect of debt financing and cash holdings on firm value in Ghana.
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- 2018
76. Cytophilic Antibodies Against Key Plasmodium falciparum Blood Stage Antigens Contribute to Protection Against Clinical Malaria in a High Transmission Region of Eastern India
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Asier Garcia-Senosiain, Michael Theisen, Régis Wendpayangde Tiendrebeogo, Bright Adu, Bishwanath Kumar Chourasia, Surya K. Sharma, Ikhlaq Hussain Kana, Manoj K. Das, Pawan Malhotra, Subhash Singh, and Susheel K. Singh
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Adult ,Male ,0301 basic medicine ,Adolescent ,Endemic Diseases ,Plasmodium falciparum ,Population ,Antibodies, Protozoan ,India ,Adaptive Immunity ,Immunoglobulin E ,Immunoglobulin G ,Young Adult ,03 medical and health sciences ,Phagocytosis ,Antigen ,parasitic diseases ,medicine ,Humans ,Immunology and Allergy ,Longitudinal Studies ,Malaria, Falciparum ,Child ,education ,education.field_of_study ,biology ,Merozoites ,Malaria vaccine ,Middle Aged ,medicine.disease ,biology.organism_classification ,030104 developmental biology ,Infectious Diseases ,Child, Preschool ,Immunology ,biology.protein ,Female ,Antibody ,Malaria - Abstract
Background The collection of clinical data from a tribal population in a malaria-endemic area of India suggests the occurrence of naturally acquired immunity (NAI) against Plasmodium falciparum malaria. Methods Quantity and functionality of immunoglobulin G (IgG) antibodies against intact merozoites and recombinant proteins were assessed in a 13-month longitudinal cohort study of 121 individuals, 3-60 years of age. Results Opsonic phagocytosis of merozoites activity was strongly associated (hazard ratio [HR] = 0.34; 95% confidence interval [CI] = .18-.66; P = .0013) with protection against febrile malaria. Of the different IgG subclasses, only IgG3 antibodies against intact whole merozoites was significantly associated with protection against febrile malaria (HR = 0.47; 95% CI = .26-.86; P = .01). Furthermore, a combination of IgG3 antibody responses against Pf12, MSP3.7, MSP3.3, and MSP2FC27 was strongly associated with protection against febrile malaria (HR = 0.15; 95% CI, .06-.37; P = .0001). Conclusions These data suggest that NAI may, at least in part, be explained by opsonic phagocytosis of merozoites and IgG3 responses against whole merozoites, and in particular to a combination of 4 antigens is critical in this population. These results may have implications in the development of a subunit malaria vaccine. Opsonic phagocytosis of Plasmodium falciparum merozoites was associated with protection against clinical malaria in an India population. Antibody profiling identified four merozoite antigens (Pf12, MSP3.7, MSP3.3, and MSP2) as targets of protective Immunoglobuline G3 antibodies.
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- 2018
77. Falling Short with Participation — Different Effects of Ideation, Commenting, and Evaluating Behavior on Open Strategizing
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Katja Hutter, Johann Füller, and Bright Adu Nketia
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business.industry ,Strategy and Management ,media_common.quotation_subject ,05 social sciences ,Geography, Planning and Development ,Sense of community ,Control (management) ,Usability ,Belongingness ,Organizational commitment ,Public relations ,Feeling ,0502 economics and business ,Organizational learning ,050211 marketing ,business ,Psychology ,050203 business & management ,Finance ,Virtual community ,media_common - Abstract
Drawing on community research, we advance our understanding on open strategy (OS) by examining the forms of participation behaviors and their effects on organizational and virtual senses of community. Using data from a Siemen’s company-wide online initiative, we find that mere participation in open strategizing does not directly engender organizational sense of community (OSOC) — an employee’s perceived belongingness to the organization — but indirectly drives OSOC via a sense of virtual community (SOVC) — a feeling of virtual belongingness to other participants of the open strategy platform. Our findings further show that different forms of participation (submitting ideas, commenting, and evaluating ideas) generate divergent effects. For instance, while “commenting” and “evaluating” show a positive effect on SOVC, “submission of ideas” alone produces a negative effect on SOVC. Thus, submission of ideas may just be a way to dump one’s thoughts without necessarily being interested in the strategy or getting a better understanding of it; whereas, commenting and evaluating behaviors clearly contribute to a sense of virtual community and intellectual engagement. Furthermore, our findings indicate that a certain threshold of perceived ease of use (EoU) of the OS platform is an absolute basic requirement for participants, leading to frustration if not fulfilled. Overall, our study demonstrates that OS indeed may add to the development of better strategies, a better understanding and implementation of those strategies and enhanced organizational learning due to employees’ increased sense of community and stronger organizational commitment. However, literature has to be aware of the different effects of participation so that managers can control for them.
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- 2017
78. The Influence of Open Strategizing on Organizational Members’ Commitment to Strategy
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Bright Adu Nketia
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Strategy making ,Knowledge management ,business.industry ,media_common.quotation_subject ,05 social sciences ,050209 industrial relations ,Organizational commitment ,Sensemaking ,Public relations ,Open strategy ,Political science ,0502 economics and business ,Strategy research ,General Materials Science ,business ,Empowerment ,Inclusion (education) ,050203 business & management ,media_common - Abstract
Wider organizational actors’ integration in strategy making should plausibly result in increased identification and Commitment to Strategy. Yet, there is a dearth of studies exploring employees’ involvement in strategizing let alone their commitment to strategy. Open Strategy (OS) is a recent trend in strategy research that facilitates such broader participative inclusion in strategizing. This conceptual paper contributes to strategy research by advancing understanding of Open Strategy, specifically shedding light on how OS promotes organizational actors’ cultivation of a higher commitment to strategy. It also explicates the mediating roles of the Individual Empowerment and Sensemaking constructs between the relationship of actors’ participation in OS and their commitment to strategy. Overall, the study extends the notion of participation to include broader organizational actors, contending that their engagement in organization-wide strategy making highly influences their commitment to strategy.
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- 2016
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79. Peripheral Merozoite Surface Proteins Are Targets of Naturally Acquired Immunity against Malaria in both India and Ghana
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Michael Theisen, Daniel Dodoo, Manoj K. Das, Bishwanath Kumar Chourasia, Susheel K. Singh, Ikhlaq Hussain Kana, Subhash Singh, Asier Garcia-Senosiain, and Bright Adu
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0301 basic medicine ,Adult ,Adolescent ,Immunology ,Plasmodium falciparum ,Protozoan Proteins ,Antibodies, Protozoan ,India ,Biology ,Adaptive Immunity ,Microbiology ,Ghana ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Antigen ,Immunity ,parasitic diseases ,medicine ,Humans ,030212 general & internal medicine ,Longitudinal Studies ,Longitudinal cohort ,Malaria, Falciparum ,Child ,Aged ,Aged, 80 and over ,Merozoites ,Hazard ratio ,Infant ,Membrane Proteins ,Middle Aged ,medicine.disease ,biology.organism_classification ,Acquired immune system ,Virology ,030104 developmental biology ,Infectious Diseases ,Child, Preschool ,biology.protein ,Parasitology ,Antibody ,Fungal and Parasitic Infections ,Malaria - Abstract
Development of a successful blood-stage vaccine against Plasmodium falciparum malaria remains a high priority. Immune-epidemiological studies are effective tools for the identification of antigenic targets of naturally acquired immunity (NAI) against malaria. However, differences in study design and methodology may compromise interstudy comparisons. Here, we assessed antibody responses against intact merozoites and a panel of 24 recombinant merozoite antigens in longitudinal cohort studies of Ghanaian (n = 115) and Indian (n = 121) populations using the same reagents and statistical methods. Anti-merozoite antibodies were associated with NAI in both the Indian (hazard ratio [HR] = 0.41, P = 0.020) and the Ghanaian (HR = 0.17, P < 0.001) participants. Of the 24 antigen-specific antibodies quantified, 12 and 8 were found to be protective in India and Ghana, respectively. Using least absolute shrinkage and selection operator (LASSO) regression, a powerful variable subselection technique, we identified subsets of four (MSP6, MSP3.7, MSPDBL2, and Pf12) and five (cMSP3(3D7), MSP3.3, MSPDBL1, GLURP-R2, and RALP-1) antigens that explained NAI better than the individual antibodies in India (HR = 0.18, P < 0.001) and Ghana (HR = 0.31, P < 0.001), respectively. IgG1 and/or IgG3 subclasses against five antigens from these subsets were associated with protection. Through this comparative study, maintaining uniformity of reagents and methodology, we demonstrate that NAI across diverse geographic regions may result from antibodies to multiple antigenic targets that constitute the peripheral merozoite surface protein complexes.
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- 2019
80. The
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Susheel K, Singh, Jordan, Plieskatt, Bishwanath Kumar, Chourasia, Vandana, Singh, Judith M, Bolscher, Koen J, Dechering, Bright, Adu, Blanca, López-Méndez, Swarnendu, Kaviraj, Emily, Locke, C Richter, King, and Michael, Theisen
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Protein Folding ,Protein Stability ,Plasmodium falciparum ,Protozoan Proteins ,Gene Expression ,Recombinant Proteins ,Cell Line ,Lactococcus lactis ,Mice ,Solubility ,Malaria Vaccines ,Protein Structure and Folding ,Animals ,Humans ,Female ,Malaria, Falciparum - Abstract
The Plasmodium falciparum circumsporozoite protein (PfCSP) is a sporozoite surface protein whose role in sporozoite motility and cell invasion has made it the leading candidate for a pre-erythrocytic malaria vaccine. However, production of high yields of soluble recombinant PfCSP, including its extensive NANP and NVDP repeats, has proven problematic. Here, we report on the development and characterization of a secreted, soluble, and stable full-length PfCSP (containing 4 NVDP and 38 NANP repeats) produced in the Lactococcus lactis expression system. The recombinant full-length PfCSP, denoted PfCSP4/38, was produced initially with a histidine tag and purified by a simple two-step procedure. Importantly, the recombinant PfCSP4/38 retained a conformational epitope for antibodies as confirmed by both in vivo and in vitro characterizations. We characterized this complex protein by HPLC, light scattering, MS analysis, differential scanning fluorimetry, CD, SDS-PAGE, and immunoblotting with conformation-dependent and -independent mAbs, which confirmed it to be both pure and soluble. Moreover, we found that the recombinant protein is stable at both frozen and elevated-temperature storage conditions. When we used L. lactis–derived PfCSP4/38 to immunize mice, it elicited high levels of functional antibodies that had the capacity to modify sporozoite motility in vitro. We concluded that the reported yield, purity, results of biophysical analyses, and stability of PfCSP4/38 warrant further consideration of using the L. lactis system for the production of circumsporozoite proteins for preclinical and clinical applications in malaria vaccine development.
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- 2019
81. Association between alpha-thalassaemia trait, Plasmodium falciparum asexual parasites and gametocyte carriage in a malaria endemic area in Southern Ghana
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Kwadwo A. Kusi, Isabella A. Quakyi, Bright Adu, Michael Alifrangis, Michael F. Ofori, Emmanuel K. Dickson, and Helena Lamptey
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Male ,0301 basic medicine ,Alpha-thalassaemia ,Prevalence ,lcsh:Medicine ,Physiology ,Parasitemia ,Ghana ,0302 clinical medicine ,Pregnancy ,Parasite hosting ,030212 general & internal medicine ,Malaria, Falciparum ,Pregnancy Complications, Infectious ,Child ,lcsh:QH301-705.5 ,biology ,General Medicine ,Middle Aged ,Gametocyte carriage ,Research Note ,Child, Preschool ,Carrier State ,Trait ,Female ,Adult ,Adolescent ,Plasmodium falciparum ,General Biochemistry, Genetics and Molecular Biology ,Submicroscopic parasites ,Young Adult ,03 medical and health sciences ,alpha-Thalassemia ,Reproduction, Asexual ,parasitic diseases ,medicine ,Gametocyte ,Humans ,lcsh:Science (General) ,Aged ,lcsh:R ,medicine.disease ,biology.organism_classification ,Germ Cells ,030104 developmental biology ,Carriage ,lcsh:Biology (General) ,Malaria ,lcsh:Q1-390 - Abstract
OBJECTIVE: The alpha-thalassaemia trait has been associated with protection against severe malaria but its role in Plasmodium falciparum asexual parasite and gametocyte carriage remains unclear. This study examined association between prevalence of α-thalassaemia and P. falciparum asexual stage parasitaemia and gametocytaemia in children, pregnant women and adults, which was part of a bigger study that investigated some key factors that influence gametocyte carriage.RESULTS: Overall prevalence of heterozygous α-thalassaemia trait among all the groups was 39.0%, while 8.2% were homozygous alpha thalassaemia. Asexual parasite prevalence was significantly higher in children (P = 0.008) compared to adults and pregnant women. Of the asexual P. falciparum positive individuals, gametocyte prevalence was 38.5% (15/39) in children, 29.7% (11/37) in pregnant women and 17.4% (4/23) in adults. Heterozygous α-thalassaemic children were less likely to harbour asexual parasites, compared with normal and those deficient (OR = 0.52; 95% CI 0.28-0.97; P = 0.037) under the dominant model. These heterozygous children were also associated with reduced risk of parasitaemia compared to heterozygous adults and pregnant women. Children with heterozygous α-thalassaemia trait had reduced risk of asexual parasite carriage. There was however, no association between α-thalassaemia trait and risk of gametocyte carriage.
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- 2019
82. Necator Americanus and Plasmodium Falciparum Co-Infection and Albendazole Treatment Outcome among Individuals in Rural Ghana
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Ben Gyan, Bright Adu, Michael D. Wilson, Benjamin Amoani, Margaret T. Frempong, Michael Cappello, and Precious Barnes
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biology ,Treatment outcome ,medicine ,Plasmodium falciparum ,biology.organism_classification ,Virology ,Necator americanus ,Albendazole ,medicine.drug ,Co infection - Published
- 2019
83. A STAT6 Intronic Single-Nucleotide Polymorphism is Associated with Clinical Malaria in Ghanaian Children
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Daniel Amoako-Sakyi, George O. Adjei, Ben Gyan, Selorme Adukpo, Dominic E. Edoh, Sharif Buari Abubakari, Bartholomew D. Akanmori, Daniel Dodoo, Bamenla Q. Goka, John Arko-Mensah, Dorcas Obiri-Yeboah, Michael F. Ofori, Godfred Futagbi, Kwadwo A. Kusi, Charles A. Brown, Richard H. Asmah, Marita Troye-Blomberg, and Bright Adu
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intron ,lcsh:QH426-470 ,030231 tropical medicine ,malaria ,SNP ,Single-nucleotide polymorphism ,Immunoglobulin E ,Bioinformatics ,Biochemistry ,Ghana ,Pathogenesis ,03 medical and health sciences ,0302 clinical medicine ,Genotype ,parasitic diseases ,Genetics ,medicine ,030212 general & internal medicine ,Genotyping ,Original Research ,STAT6 ,biology ,business.industry ,Plasmodium falciparum ,biology.organism_classification ,medicine.disease ,lcsh:Genetics ,Cerebral Malaria ,Immunology ,biology.protein ,IgE ,business ,Malaria ,rs3024974 - Abstract
Malaria pathogenesis may be influenced by IgE responses and cytokine cross-regulation. Several mutations in the IL-4/STAT6 signaling pathway can alter cytokine cross-regulation and IgE responses during a Plasmodium falciparum malarial infection. This study investigated the relationship between a STAT6 intronic single-nucleotide polymorphism (rs3024974), total IgE, cytokines, and malaria severity in 238 Ghanaian children aged between 0.5 and 13 years. Total IgE and cytokine levels were measured by ELISA, while genotyping was done by polymerase chain reaction-restriction fragment length polymorphism (RFLP). Compared with healthy controls, heterozygosity protected against clinical malaria: uncomplicated malaria (odds ratios [OR] = 0.13, P < 0.001), severe malarial anemia (OR = 0.18, P < 0.001), and cerebral malaria (OR = 0.39, P = 0.022). Levels of total IgE significantly differed among malaria phenotypes (P = 0.044) and rs3024974 genotypes (P = 0.037). Neither cytokine levels nor IL-6/IL-10 ratios were associated with malaria phenotypes or rs3024974 genotypes. This study suggests a role for rs3024974 in malaria pathogenesis and offers further insights into an IL-4/STAT6 pathway mutation in malaria pathogenesis.
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- 2016
84. Enteric Pathogenic Infection in Young Ghanaian Children and Associations with Iron-Deficiency and Anemia
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Andrew D. Jones, Dave Bridges, Nathalie J Lambrecht, Bright Adu, Joseph N. S. Eisenberg, Ana Baylin, Mark L. Wilson, and Gloria Folson
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Global Nutrition ,Nutrition and Dietetics ,Anemia ,business.industry ,Campylobacter ,Medicine (miscellaneous) ,Iron deficiency ,Stool specimen ,medicine.disease ,Pathogenicity ,medicine.disease_cause ,Vitamin A deficiency ,Immunology ,medicine ,Hemoglobin ,business ,Malaria ,Food Science - Abstract
OBJECTIVES: We aimed to determine the burden of Campylobacter infection among children in Greater Accra, Ghana and assess whether infection is associated with iron-deficiency and anemia. METHODS: Blood and stool samples were collected from a random sample of 259 children aged 6 to 59 months residing in two districts in the Greater Accra Region, Ghana. Blood samples were analyzed for hemoglobin (Hb) concentration, the iron status biomarkers serum ferritin (SF) and serum transferrin receptor (sTfR), and the inflammatory biomarkers C-reactive protein (CRP) and α-1-acid glycoprotein (AGP). Anemia was defined as Hb 8.3 mg/L. We used quantitative polymerase chain reaction (qPCR) to analyze bacterial DNA from stool samples for Campylobacter species. Multivariate logistic regression was used to assess child- and household-level predictors of infection. RESULTS: Overall, 16.2% of children were positive for Campylobacter infection, with the highest infection prevalence among children under two years old. Children positive for Campylobacter infection had 3.4 times higher odds of elevated CRP levels (95% CI: 1.66, 7.05) and 3.0 times higher odds of elevated AGP levels (95% CI: 1.61, 5.76), after adjusting for child age and sex, vitamin A deficiency, malaria, and household sanitation and wealth. Campylobacter infection was associated with 2.5 times higher odds of low SF (95% CI: 1.20, 5.12) and marginally higher odds of elevated sTfR (OR: 2.10, 95% CI: 0.96, 4.58), but was not significantly associated with higher odds of anemia (OR: 1.15, 95% CI: 0.69, 1.93). Ownership of small livestock, including goats, sheep, and pigs, but no other livestock, was associated with Campylobacter infection. CONCLUSIONS: Our results suggest that Campylobacter infection contributes to the inflammatory burden among young children in Ghana and that infection may also negatively affect iron status. Furthermore, livestock may contribute to infectious pathogen exposure. FUNDING SOURCES: University of Michigan (U-M) International Institute, U-M Office of Global Public Health, U-M African Studies Center, U-M Rackham Graduate School, U-M Nutritional Sciences Department, the Dow Chemical Company Foundation through the Dow Sustainability Fellows Program at the University of Michigan.
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- 2020
85. The prevalence of submicroscopic Plasmodium falciparum gametocyte carriage and multiplicity of infection in children, pregnant women and adults in a low malaria transmission area in Southern Ghana
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Samuel Bosomprah, Eunice Owusu-Yeboa, Andrea Twumwaa Arku, Kwadwo A. Kusi, Isabella A. Quakyi, Bright Adu, Michael Alifrangis, Eric Kyei-Baafour, Michael F. Ofori, and Helena Lamptey
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Male ,0301 basic medicine ,Protozoan Proteins ,Seroprevalence ,Antibodies, Protozoan ,Physiology ,Parasitemia ,Ghana ,Polymerase Chain Reaction ,0302 clinical medicine ,Multiplicity of infection ,Pregnancy ,Prevalence ,Malaria, Falciparum ,Pregnancy Complications, Infectious ,Child ,Microscopy ,biology ,Middle Aged ,Infectious Diseases ,Child, Preschool ,Pfs230 ,Carrier State ,Female ,Antibody ,Adult ,medicine.medical_specialty ,lcsh:Arctic medicine. Tropical medicine ,Adolescent ,Genotype ,Gametocyte prevalence ,lcsh:RC955-962 ,Plasmodium falciparum ,030231 tropical medicine ,Antigens, Protozoan ,Enzyme-Linked Immunosorbent Assay ,lcsh:Infectious and parasitic diseases ,Young Adult ,03 medical and health sciences ,parasitic diseases ,medicine ,Gametocyte ,Humans ,lcsh:RC109-216 ,business.industry ,Submicroscopic infections ,medicine.disease ,biology.organism_classification ,Cross-Sectional Studies ,030104 developmental biology ,Carriage ,Parasitology ,Immunoglobulin G ,Tropical medicine ,biology.protein ,business ,Malaria - Abstract
Background The gametocyte stage of Plasmodium falciparum is considered an important target for disrupting malaria transmission. Indications are that various demographic groups, such as children and pregnant women may differ in risk of harbouring gametocytes, which may be crucial for targeted control. In this study, the relationship between the prevalence and multiplicity of P. falciparum, asexual parasite infections and gametocytaemia was assessed in three different demographic groups in an area of southern Ghana with low malaria endemicity. Levels of antibody responses to Pfs230 were also assessed as a proxy for the presence of gametocytes. Methods The study involved multiple cross-sectional sampling of children (N = 184, aged 2–15 years), male and non-pregnant female adults (N = 154, aged 16–65 years) and pregnant women (N = 125, aged 18–45 years) from Asutsuare in the Shai Osudoku District of Greater Accra Region in Ghana. Asexual parasitaemia was detected by microscopy and PCR, and gametocytaemia was assessed by Pfs25-real time PCR. Multiclonal P. falciparum infections were estimated by msp2 genotyping and an indirect ELISA was used to measure plasma IgG antibodies to Pfs230 antigen. Results Overall, children and pregnant women had higher prevalence of submicroscopic gametocytes (39.5% and 29.7%, respectively) compared to adults (17.4%). Multiplicity of infection observed amongst children (3.1) and pregnant women (3.9) were found to be significantly higher (P = 0.006) compared with adults (2.7). Risk of gametocyte carriage was higher in individuals infected with P. falciparum having both Pfmsp2 3D7 and FC27 parasite types (OR = 5.92, 95% CI 1.56–22.54, P = 0.009) compared with those infected with only 3D7 or FC27 parasite types. In agreement with the parasite prevalence data, anti-Pfs230 antibody levels were lower in gametocyte positive adults (β = − 0.57, 95% CI − 0.81, − 0.34, P
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- 2018
86. Cytokine profiles of Necator americanus and Plasmodium falciparum co-infected patients in rural Ghana
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Samuel Victor Nuvor, Ben Gyan, Michael D. Wilson, Michael Cappello, Bright Adu, Emmanuel Kwasi Abu, Margaret T. Frempong, Benjamin Amoani, Lisa M. Harrison, and Tracy Sarkodie-Addo
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STHs, Soil Transmitted Helminths ,lcsh:Immunologic diseases. Allergy ,Hookworm ,Albendazole treatment ,Necator americanus ,education ,Plasmodium falciparum ,Immunology ,Parasitemia ,Biochemistry ,Albendazole ,Deworming ,EPG, Egg per Gram ,parasitic diseases ,medicine ,Immunology and Allergy ,Parasite hosting ,Helminths ,Cytokine ,Molecular Biology ,Eggs per gram ,integumentary system ,biology ,CCL11, Eotaxin ,Hematology ,biology.organism_classification ,medicine.disease ,Infection intensity ,lcsh:RC581-607 ,Research Article ,medicine.drug - Abstract
Highlights • Co-infection of hookworm with P. falciparum modulates blood parasitemia levels. • Cytokine levels were higher in the parasite infected individuals. • Serum eotaxin level correlate negatively with hookworm intensity. • Deworming drug treatment alters cytokine profiles in hookworm infected subjects., Background Necator americanus (hookworm) and Plasmodium falciparum co-infections are common in endemic communities in rural Ghana. Human immune responses to P. falciparum and hookworm are complex, and the dynamics of cytokine levels and effector mediators are poorly understood. This study aimed to determine the effect of hookworm and P. falciparum co-infection on parasite intensities and cytokine profiles in individuals before and after deworming drug treatment. Methods In this cross-sectional study conducted in the Kintampo North Municipality of Ghana blood and stool samples were analyzed from 984 participants (aged 4–88 years). Stool samples were collected at baseline from all participants and examined for the presence of hookworm using the Kato-Katz method. Blood and stool samples were analysed again two weeks after albendazole treatment of hookworm infected individuals. Malaria parasitaemia was estimated by light microscopy and P. falciparum-specific 18S rRNA gene PCR method used for species identification. Serum levels of circulating cytokines interleukins -5, -10 (IL-5, IL-10), tumor necrosis factor [TNF]-α, and eotaxin [CCL11] were determined using ELISA based methods. Results Malaria parasitaemia was significantly reduced in hookworm and P. falciparum co-infected individuals (p = 0.0018) while hookworm intensity was similar between groups. IL-10 level was significantly higher in the co-infected individuals (39.9 ± 12.2 pg/ml) compared to the single infected or the uninfected group (10.7 ± 7.6 mg/ml). IL-5 level was higher in the hookworm only infected individual. TNF-α levels were higher in all infected groups compared to the uninfected controls. CCL11 levels were significantly higher in subjects infected with hookworm only or co-infected with hookworm and P. falciparum. There was a significantly negative correlation (rs = −0.39, p = 0.021) between hookworm eggs per gram of stool and CCL11 levels in the group mono-infected with hookworm which was not affected by treatment. Treatment with albendazole led to a significant reduction of TNF-α (p = 0.041), IL-5 (p = 0.01) and IL-10 (p = 0.001) levels. Conclusion This study shows that in the absence of other helminths, co-infection of hookworm with P. falciparum may modulate blood parasitemia levels and cytokine responses. Data also show that deworming drug treatment alters these cytokine profiles in hookworm infected subjects. Future studies to elucidate the potential mechanisms underlying these observations should include an assessment of parasite specific cellular responses.
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- 2019
87. MOESM1 of The prevalence of submicroscopic Plasmodium falciparum gametocyte carriage and multiplicity of infection in children, pregnant women and adults in a low malaria transmission area in Southern Ghana
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Lamptey, Helena, Ofori, Michael, Kwadwo Kusi, Bright Adu, Owusu-Yeboa, Eunice, Kyei-Baafour, Eric, Arku, Andrea, Bosomprah, Samuel, Alifrangis, Michael, and Quakyi, Isabella
- Abstract
Additional file 1. Asexual parasite prevalence data among the groups at various time points by Microscopy and PCR. Baseline, November 2013; F1-3 are follow-ups 1-3 (February 2014, May 2014 and September 2014) respectively.
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- 2018
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88. Malaria epidemiology in an area of stable transmission in tribal population of Jharkhand, India
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Brijesh K. Prajapati, Manoj K. Das, Ikhlaq Hussain Kana, Harvinder Kour Khera, Kumud Ranjan, Narendra Chauhan, Régis Wendpayangde Tiendrebeogo, Michael Theisen, Subhash C. Singh, Surya K. Sharma, Amit Kumar Srivastava, Sanjay Tevatiya, and Bright Adu
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Male ,Veterinary medicine ,Anopheles annularis ,Plasmodium vivax ,Prevalence ,Jharkhand ,0302 clinical medicine ,Medicine ,030212 general & internal medicine ,Longitudinal Studies ,Malaria, Falciparum ,Anopheles culicifacies ,Child ,Aged, 80 and over ,education.field_of_study ,biology ,Incidence ,Middle Aged ,Infectious Diseases ,Child, Preschool ,Population study ,Female ,Seasons ,Adult ,lcsh:Arctic medicine. Tropical medicine ,Adolescent ,lcsh:RC955-962 ,030231 tropical medicine ,Population ,Plasmodium falciparum ,India ,lcsh:Infectious and parasitic diseases ,03 medical and health sciences ,Young Adult ,Age ,parasitic diseases ,Malaria, Vivax ,Animals ,Humans ,lcsh:RC109-216 ,education ,Aged ,Demography ,business.industry ,Research ,Infant, Newborn ,Infant ,biology.organism_classification ,medicine.disease ,Malaria ,Insect Vectors ,Cross-Sectional Studies ,Parasitology ,Morbidity ,business - Abstract
BACKGROUND: Malaria remains an important health problem in India with approximately 1 million cases in 2014. Of these, 7% occurred in the Jharkhand state mainly in the tribal population.METHODS: This study was conducted in Dumargarhi, a tribal village about 42 km east of Ranchi city, Jharkhand, from May 2014 to September 2016. Four point prevalence surveys were carried out during consecutive high (October-December) and low (June-August) transmission seasons. Malaria cases were recorded from April 2015 to April 2016 through fortnightly visits to the village. Adult mosquito densities were monitored fortnightly by manual catching using suction tube method.RESULTS: The study area consists of five hamlets inhabited by 945 individuals living in 164 households as recorded through a house-to-house census survey performed at enrollment. The study population consisted predominantly of the Munda (n = 425, 45%) and Oraon (n = 217, 23%) ethnic groups. Study participants were categorized as per their age 0-5, 6-10, 11-15 and >15 years. There were 99 cases of clinical malaria from April 2015 to April 2016 and all malaria cases confirmed by microscopy were attributed to Plasmodium falciparum (94 cases) and Plasmodium vivax (5 cases), respectively. During the high transmission season the mean density of P. falciparum parasitaemia per age group increased to a peak level of 23,601 parasites/μl in the 6-10 years age group and gradually declined in the adult population. Malaria attack rates, parasite prevalence and density levels in the study population showed a gradual decrease with increasing age. This finding is consistent with the phenomenon of naturally acquired immunity against malaria. Three vector species were detected: Anopheles fluviatilis, Anopheles annularis, and Anopheles culicifacies. The incoherence or complete out of phase pattern of the vector density peaks together with a high prevalence of parasite positive individuals in the study population explains the year-round malaria transmission in the study region.CONCLUSIONS: The collection of clinical data from a well-characterized tribal cohort from Jharkhand, India, has provided evidence for naturally acquired immunity against malaria in this hyperendemic region. The study also suggests that enforcement of existing control programmes can reduce the malaria burden further.
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- 2017
89. T-cell responses against Malaria: Effect of parasite antigen diversity and relevance for vaccine development
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Kwadwo A. Kusi, Omarine Nfor Nlinwe, Bright Adu, and Martha Sedegah
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0301 basic medicine ,medicine.medical_specialty ,T cell ,T-Lymphocytes ,Protozoan Proteins ,Antibodies, Protozoan ,Antigens, Protozoan ,Biology ,03 medical and health sciences ,Immune system ,Antigen ,Immunity ,parasitic diseases ,Malaria Vaccines ,medicine ,Animals ,Humans ,Parasites ,Malaria, Falciparum ,B cell ,B-Lymphocytes ,General Veterinary ,General Immunology and Microbiology ,Malaria vaccine ,Public health ,Public Health, Environmental and Occupational Health ,medicine.disease ,Antigenic Variation ,Malaria ,030104 developmental biology ,Infectious Diseases ,medicine.anatomical_structure ,Immunology ,Molecular Medicine - Abstract
The on-going agenda for global malaria elimination will require the development of additional disease control and prevention measures since currently available tools are showing signs of inadequacy. Malaria vaccines are seen as one such important addition to the control arsenal since vaccines have proven to be highly effective public health tools against important human diseases. Both cell-mediated and antibody responses are generally believed to be important for malaria parasite control, although the exact targets of T and B cell responses against malaria have not been clearly defined. However, our current understanding of the immune response to malaria suggests that T cell responses against multiple antigenic targets may potentially be key for the development of a highly efficacious malaria vaccine. This review takes a comprehensive look at the available literature on T cell-mediated immunity against all human stages of the malaria parasite and the effect of antigen diversity on these responses. The implications of these interrelationships for the development of an effective vaccine for malaria are also highlighted.
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- 2017
90. A multi-stage malaria vaccine candidate targeting both transmission and asexual parasite life-cycle stages
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Michael Christiansen, Theo Arens, Bright Adu, Marga van de Vegte-Bolmer, Robert W. Sauerwein, Will Roeffen, Teun Bousema, Linda E. Amoah, Régis Wendpayangde Tiendrebeogo, Susheel K. Singh, Gorm Andersen, Morten Hanefeld Dziegiel, Sophie Jones, and Michael Theisen
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Plasmodium falciparum ,Protozoan Proteins ,lnfectious Diseases and Global Health Radboud Institute for Molecular Life Sciences [Radboudumc 4] ,Antibodies, Protozoan ,Force of infection ,Biology ,Chimera (genetics) ,Antigen ,Anopheles ,Malaria Vaccines ,medicine ,Gametocyte ,Animals ,Malaria, Falciparum ,Rats, Wistar ,Membrane Glycoproteins ,General Veterinary ,General Immunology and Microbiology ,Malaria vaccine ,Immune Sera ,Public Health, Environmental and Occupational Health ,medicine.disease ,biology.organism_classification ,Virology ,Recombinant Proteins ,3. Good health ,lnfectious Diseases and Global Health Radboud Institute for Health Sciences [Radboudumc 4] ,Infectious Diseases ,Immunoglobulin G ,Antibody Formation ,Vaccines, Subunit ,biology.protein ,Molecular Medicine ,Antibody ,Malaria - Abstract
Effective control and eventual eradication of malaria drives the imperative need for clinical development of a malaria vaccine. Asexual parasite forms are responsible for clinical disease and death while apathogenic gametocytes are responsible for transmission from man to mosquito. Vaccines that combine antigens from both stages may provide direct protection and indirect benefit by reducing the force of infection. We constructed a chimeric antigen composed of a fragment of the Plasmodium falciparum (Pf) glutamate-rich protein fused in frame to a correctly folded fragment of Pfs48/45. The chimera was produced in Lactococcus lactis and induced robust antibody responses in rodents to the individual components. Specific antibodies showed strong transmission blocking activity against multiple Pf-strains in the standard membrane feeding assay and functional activity against asexual stages in the antibody dependent cellular inhibition assay. The combined data provide a strong rationale for entering the next phase of clinical grade production and testing.
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- 2014
91. Levels of serum eosinophil cationic protein are associated with hookworm infection and intensity in endemic communities in Ghana
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Ben Gyan, Michael D. Wilson, Bright Adu, Samuel Victor Nuvor, Benjamin Amoani, Margaret T. Frempong, and Tracy Sarkodie-Addo
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Ancylostomatoidea ,Male ,0301 basic medicine ,Plasmodium ,Nematoda ,Serum Eosinophil Cationic Protein ,Cross-sectional study ,Ghana ,White Blood Cells ,Feces ,fluids and secretions ,0302 clinical medicine ,Animal Cells ,Medicine and Health Sciences ,Prevalence ,Medicine ,Enzyme-Linked Immunoassays ,Malaria, Falciparum ,Child ,Aged, 80 and over ,Eosinophil cationic protein ,Multidisciplinary ,biology ,Eukaryota ,Necator ,Middle Aged ,3. Good health ,Infectious Diseases ,Helminth Infections ,Child, Preschool ,Biomarker (medicine) ,Female ,Cellular Types ,Research Article ,Adult ,Adolescent ,Immune Cells ,Science ,Immunology ,education ,030231 tropical medicine ,Research and Analysis Methods ,Necator americanus ,Hookworm Infections ,03 medical and health sciences ,Helminths ,Parasite Groups ,parasitic diseases ,Parasitic Diseases ,Animals ,Humans ,Immunoassays ,Hookworm infection ,Aged ,Blood Cells ,business.industry ,Eosinophil Cationic Protein ,Organisms ,Biology and Life Sciences ,Plasmodium falciparum ,Cell Biology ,medicine.disease ,biology.organism_classification ,Invertebrates ,Eosinophils ,Cross-Sectional Studies ,030104 developmental biology ,Hookworms ,Co-Infections ,Necator Americanus ,Immunologic Techniques ,Parasitology ,business ,Apicomplexa ,Biomarkers ,Malaria - Abstract
BackgroundThe eosinophil cationic protein (ECP) is a cytotoxic protein mainly secreted by eosinophils granulocytes and plays a role in host defense against parasitic infections. Infection with Necator americanus (hookworm) is traditionally diagnosed by the Kato-Katz method which is inherently tedious, subjective and known to underestimate infection intensity. This study aimed to assess levels of serum ECP in relation to hookworm infection intensity.MethodsStool samples from 984 (aged 4 to 80 years) participants in a cross-sectional study conducted in the Kintampo North Municipality of Ghana were examined using the Kato-Katz and formol-ether concentration methods. Serum ECP levels were measured by ECP assay kit and compared between 40 individuals infected with hookworm only, 63 with hookworm- Plasmodium falciparum co-infection, 59 with P. falciparum infection and 36 with no infection.ResultsHookworm infection prevalence was 18.1% (178/984). ECP levels were significantly higher in individuals infected with hookworm only (β = 2.96, 95%CI = 2.69, 3.23, p0.05). Increased hookworm intensity was associated with a significant increase in ECP level (β = 4.45, 95%CI = 2.25, 9.11, rs = 0.193, n = 103, pConclusionSerum ECP level may be a good biomarker of hookworm infection and intensity and warrant further investigations to help improve current hookworm diagnosis.
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- 2019
92. Individual innovation behavior and firm-level exploration and exploitation: how family firms make the most of their managers.
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Strobl, Andreas, Matzler, Kurt, Nketia, Bright Adu, and Veider, Viktoria
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This study investigates the influence of top managers' individual innovation behavior on firm-level innovation activities, specifically on exploration and exploitation. The influence of individual actions depends on managerial discretion, which is dependent on the ownership context of a business. Thus, this study explores how family ownership moderates the relationships between a top manager's individual innovation behavior and firm-level exploration and exploitation. Based on a sample of 195 firms, of which 120 are family firms, our findings depict highly significant relationships between managers' individual innovation behavior and firm-level exploration and exploitation innovation. Furthermore, we find differences regarding these relationships between family firms and their non-family counterparts. We contribute to literature showing that family firms provide a unique context for leveraging a top manager's individual innovation behavior into firm-level exploration activities. [ABSTRACT FROM AUTHOR]
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- 2020
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93. Individual innovation behavior and firm-level exploration and exploitation: how family firms make the most of their managers
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Strobl, Andreas, primary, Matzler, Kurt, additional, Nketia, Bright Adu, additional, and Veider, Viktoria, additional
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- 2018
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94. Open strategizing : exploring the implications of wider organizational actors' strategic agency
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Nketia, Bright Adu and Nketia, Bright Adu
- Abstract
Diese kumulative Dissertation verfolgt einen explorativen Ansatz, um die Implikationen des „Open Strategy“ Phänomens hinsichtlich der Einbeziehung jener Mitarbeiter, welcher nicht zur Vorstandsebene gehören und somit typischerweise nicht in die Strategiearbeit einbezogen sind, zu untersuchen. Die Kernbotschaft des „Open Strategy“ Paradigmas ist die Öffnung der Unternehmensstrategie in Richtung mehr Transparenz und Inklusion im gesamten Strategieprozess. Die Dissertation umfasst vier Studien, konzeptionell ebenso wie empirisch, welche sich auf qualitative und quantitative Querschnittsdaten stützen. Diese Arbeit liefert spezifische Beiträge zum Forschungsbereich „Open Strategy“ und zur Literatur rund um das Thema Unternehmensstrategie generell. Es werden sowohl Antezedenzien, Konsequenzen, als auch Barrieren hinsichtlich der Eingliederung der Mitarbeiter in die Strategiegestaltung mittels Web 2.0 Technologie aufgezeigt und bearbeitet., This cumulative dissertation takes an explorative approach to investigate the implications of the open strategy phenomenon relative to the inclusion of wider non-managerial employees; these actors are usually excluded in strategizing or tend to play minimal roles. The core premise of the open strategy notion is attributable to more openness in the form of ‘transparency and ‘inclusiveness in the strategy making process. The dissertation entails four papers that collectively make use of cross-sectional data, empirical and conceptual designs as well as qualitative and quantitative research approaches. It broadly contributes to the open strategy notion in particular and strategy literature in general by pointing to certain effects, antecedents and constraints of employees inclusion in strategy making using Web 2.0 technologies., Bright Adu Nketia, M.Sc.BA, Abweichender Titel laut Übersetzung der Verfasserin/des Verfassers, Universität Innsbruck, Dissertation, 2017, OeBB, (VLID)2178743
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- 2017
95. Naturally Acquired Antibodies Target the Glutamate-Rich Protein on Intact Merozoites and Predict Protection Against Febrile Malaria
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Régis Wendpayangde Tiendrebeogo, Michael Theisen, Daniel Dodoo, Susheel K. Singh, Ikhlaq Hussain Kana, and Bright Adu
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0301 basic medicine ,Fever ,030231 tropical medicine ,Plasmodium falciparum ,Protozoan Proteins ,Antibodies, Protozoan ,Antigens, Protozoan ,Immunofluorescence ,Ghana ,Immunoglobulin G ,Cohort Studies ,03 medical and health sciences ,0302 clinical medicine ,Antigen ,Phagocytosis ,Immunity ,parasitic diseases ,medicine ,Immunology and Allergy ,Humans ,Longitudinal Studies ,Child ,Opsonin ,Proportional Hazards Models ,biology ,medicine.diagnostic_test ,business.industry ,Merozoites ,Infant ,biology.organism_classification ,medicine.disease ,Virology ,Malaria ,030104 developmental biology ,Infectious Diseases ,Logistic Models ,Child, Preschool ,Immunology ,biology.protein ,Antibody ,business ,Follow-Up Studies - Abstract
Background Plasmodium species antigens accessible at the time of merozoite release are likely targets of biologically functional antibodies. Methods Immunoglobulin G (IgG) antibodies against intact merozoites were quantified in the plasma of Ghanaian children from a longitudinal cohort using a novel flow cytometry-based immunofluorescence assay. Functionality of these antibodies, as well as glutamate-rich protein (GLURP)-specific affinity-purified IgG from malaria hyperimmune Liberian adults, was assessed by the opsonic phagocytosis (OP) assay. Results Opsonic phagocytosis activity was strongly associated (hazard ratio [HR] = 0.46; 95% confidence interval [CI] = .30-.73; P = .0008) with protection against febrile malaria. Of the antimerozoite-specific antibodies, only IgG3 was significantly associated with both OP and protection (HR = 0.53; 95% CI = .34-.84; Pcorrected = .03) against febrile malaria. Similarly, GLURP-specific antibodies previously shown to be protective against febrile malaria in this same cohort were significantly associated with OP activity in this study. GLURP-specific antibodies recognized merozoites and also mediated OP activity. Conclusions These findings support previous studies that found OP of merozoites to be associated with protection against malaria and further shows IgG3 and GLURP antibodies are key in the OP mechanism, thus giving further impetus for the development of malaria vaccines targeting GLURP.
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- 2016
96. Antibody levels against GLURP R2, MSP1 block 2 hybrid and AS202.11 and the risk of malaria in children living in hyperendemic (Burkina Faso) and hypo-endemic (Ghana) areas
- Author
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Issa Nebie, Sodiomon B. Sirima, Fareed K. N. Arthur, Mariama Chérif, Daniel Dodoo, Amidou Diarra, David R. Cavanagh, Michael Theisen, Bright Adu, Samuel Bosomprah, Emmanuel K. Dickson, and Giampietro Corradin
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Faculty of Health and Medical Sciences ,0301 basic medicine ,AS202.11 ,Protozoan Proteins ,Antibodies, Protozoan ,Ghana ,0302 clinical medicine ,antibodies ,Hyperendemic ,Malaria, Falciparum ,Child ,Merozoite Surface Protein 1 ,Antibodies, Protozoan/blood ,Burkina Faso/epidemiology ,Child, Preschool ,Ghana/epidemiology ,Humans ,Infant ,Malaria, Falciparum/epidemiology ,Malaria, Falciparum/immunology ,Merozoite Surface Protein 1/immunology ,Peptides/immunology ,Plasmodium falciparum/immunology ,Protozoan Proteins/immunology ,Hazard ratio ,Infectious Diseases ,Cohort ,Hypo-endemic ,Antibody ,medicine.medical_specialty ,hyperendemic ,030231 tropical medicine ,Plasmodium falciparum ,malaria ,GLURP R2 ,Biology ,Antibodies ,03 medical and health sciences ,Antigen ,Burkina Faso ,parasitic diseases ,medicine ,Transmission intensity ,hypo-endemic ,Proportional hazards model ,Research ,medicine.disease ,biology.organism_classification ,Malaria ,transmission intensity ,030104 developmental biology ,Tropical medicine ,Immunology ,biology.protein ,Parasitology ,Peptides ,MSP1 block 2 hybrid - Abstract
Background Differences in parasite transmission intensity influence the process of acquisition of host immunity to Plasmodium falciparum malaria and ultimately, the rate of malaria related morbidity and mortality. Potential vaccines being designed to complement current intervention efforts therefore need to be evaluated against different malaria endemicity backgrounds. Methods The associations between antibody responses to the chimeric merozoite surface protein 1 block 2 hybrid (MSP1 hybrid), glutamate-rich protein region 2 (GLURP R2) and the peptide AS202.11, and the risk of malaria were assessed in children living in malaria hyperendemic (Burkina Faso, n = 354) and hypo-endemic (Ghana, n = 209) areas. Using the same reagent lots and standardized protocols for both study sites, immunoglobulin (Ig) M, IgG and IgG sub-class levels to each antigen were measured by ELISA in plasma from the children (aged 6–72 months). Associations between antibody levels and risk of malaria were assessed using Cox regression models adjusting for covariates. Results There was a significant association between GLURP R2 IgG3 and reduced risk of malaria after adjusting age of children in both the Burkinabe (hazard ratio 0.82; 95 % CI 0.74–0.91, p
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- 2016
97. MOESM1 of Antibody levels against GLURP R2, MSP1 block 2 hybrid and AS202.11 and the risk of malaria in children living in hyperendemic (Burkina Faso) and hypo-endemic (Ghana) areas
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Bright Adu, Mariama Cherif, Bosomprah, Samuel, Amidou Diarra, Fareed Arthur, Dickson, Emmanuel, Corradin, Giampietro, Cavanagh, David, Theisen, Michael, Sodiomon Sirima, Nebie, Issa, and Dodoo, Daniel
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parasitic diseases - Abstract
Additional file 1: Table S1. Malaria episodes in Burkinabe and Ghanaian children in the cohorts.
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- 2016
- Full Text
- View/download PDF
98. Antibody-Dependent Cellular Inhibition Is Associated With Reduced Risk Against Febrile Malaria in a Longitudinal Cohort Study Involving Ghanaian Children
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Michael Christiansen, Régis Wendpayangde Tiendrebeogo, Sodiomon B. Sirima, Susheel K. Singh, Morten Hanefeld Dziegiel, Daniel Dodoo, Issa Nebie, Bright Adu, and Michael Theisen
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Phagocytosis ,Plasmodium falciparum ,malaria ,Immunoglobulin G ,children ,parasitic diseases ,medicine ,Opsonin ,biology ,Malaria vaccine ,business.industry ,longitudinal cohort study ,biology.organism_classification ,medicine.disease ,Respiratory burst ,Infectious Diseases ,Oncology ,Immunology ,biology.protein ,Brief Reports ,Antibody ,business ,antibody-dependent cellular inhibition ,monocytes ,Malaria - Abstract
The antibody-dependent respiratory burst and opsonic phagocytosis assays have been associated with protection against malaria; however, other mechanisms may also be involved. The antibody-dependent cellular inhibition (ADCI) assay is yet to be correlated with protection in longitudinal cohort studies (LCS). We investigated the relationship between ADCI activity of immunoglobulin G before malaria season and risk of malaria in a LCS involving Ghanaian children. High ADCI activity was significantly associated with reduced risk against malaria. Findings here suggest a potential usefulness of the ADCI assay as a correlate of protection to guide malaria vaccine studies.
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- 2015
99. High-throughput tri-colour flow cytometry technique to assess Plasmodium falciparum parasitaemia in bioassays
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Michael Christiansen, Daniel Dodoo, Régis Wendpayangde Tiendrebeogo, Morten Hanefeld Dziegiel, Michael Theisen, Benjamin Mordmüller, Bright Adu, Issa Nebie, Sodiomon B. Sirima, and Susheel K. Singh
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Adult ,Plasmodium falciparum ,Parasitemia ,Parasite Load ,Flow cytometry ,chemistry.chemical_compound ,Microscopy ,medicine ,Humans ,Parasite hosting ,Bioassay ,CD45 ,Malaria, Falciparum ,Child ,Fluorescent Dyes ,ADCI ,Coriphosphine-O ,biology ,medicine.diagnostic_test ,Mitotracker red ,Methodology ,Infant ,Flow Cytometry ,biology.organism_classification ,Molecular biology ,High-Throughput Screening Assays ,Malaria ,Staining ,Infectious Diseases ,chemistry ,Parasitology ,Child, Preschool ,Immunology ,Tri-colour ,Growth inhibition - Abstract
Background Unbiased flow cytometry-based methods have become the technique of choice in many laboratories for high-throughput, accurate assessments of malaria parasites in bioassays. A method to quantify live parasites based on mitotracker red CMXRos was recently described but consistent distinction of early ring stages of Plasmodium falciparum from uninfected red blood cells (uRBC) remains a challenge. Methods Here, a high-throughput, three-parameter (tri-colour) flow cytometry technique based on mitotracker red dye, the nucleic acid dye coriphosphine O (CPO) and the leucocyte marker CD45 for enumerating live parasites in bioassays was developed. The technique was applied to estimate the specific growth inhibition index (SGI) in the antibody-dependent cellular inhibition (ADCI) assay and compared to parasite quantification by microscopy and mitotracker red staining. The Bland-Altman analysis was used to compare biases between SGI estimated by the tri-colour staining technique, mitotracker red and by microscopy. Results CPO allowed a better separation between early rings and uRBCs compared to mitotracker red resulting in a more accurate estimate of total parasitaemia. The tri-colour technique is rapid, cost effective and robust with comparable sensitivity to microscopy and capable of discriminating between live and dead and/or compromised parasites. Staining for CD45 improved parasitaemia estimates in ADCI assay since high numbers of leucocytes interfered with the accurate identification of parasitized RBC. The least bias (-1.60) in SGI was observed between the tri-colour and microscopy. Conclusion An improved methodology for high-throughput assessment of P. falciparum parasitaemia under culture conditions that could be useful in different bioassays, including ADCI and growth inhibition assays has been developed.
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- 2014
100. Fc gamma receptor 3B (FCGR3B-c.233CA-rs5030738) polymorphism modifies the protective effect of malaria specific antibodies in Ghanaian children
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Michael Christiansen, Daniel Dodoo, Eric Kyei-Baafour, Thomas A. Gerds, Micha Phill Grønholm Jepsen, Bright Adu, and Michael Theisen
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Male ,Antibodies, Protozoan ,GPI-Linked Proteins ,Ghana ,Polymorphism, Single Nucleotide ,Immunoglobulin G ,Cohort Studies ,parasitic diseases ,Genotype ,medicine ,Immunology and Allergy ,Humans ,Genetic Predisposition to Disease ,Child ,biology ,Receptors, IgG ,Vaccine trial ,Infant ,Plasmodium falciparum ,biology.organism_classification ,medicine.disease ,Virology ,Malaria ,Infectious Diseases ,Child, Preschool ,Immunology ,biology.protein ,Neutrophil degranulation ,Fc-Gamma Receptor ,Female ,Antibody - Abstract
Immunoglobulin G (IgG) cross-linking with Fc gamma receptor IIIB (FcγRIIIB) triggers neutrophil degranulation, releasing reactive oxygen species with high levels associated with protection against malaria. The FCGR3B-c.233C>A polymorphism thought to influence the interaction between IgG and FcγRIIIB was recently associated with malaria. We studied the statistical interaction between glutamate rich protein antibodies and FCGR3B-c.233C>A genotypes on risk of malaria in a cohort of Ghanaian children. The absolute risk of malaria decreased more rapidly with increasing antibody levels for 233AA/AC individuals compared with 233CC children. This genotype related effect modification may significantly influence malaria sero-epidemiological and vaccine trial studies.
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- 2013
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