Browsing by Author "Owusu-Dabo Ellis"
Now showing 1 - 10 of 10
Results Per Page
Sort Options
- ItemAberrant plasma IL-7 and soluble IL-7 receptor levels indicate impaired T-cell response to IL-7 in human tuberculosis(PLOS, 2017) Lundtoft Christian; Nausch Norman; Owusu-Dabo Ellis; Jacobsen Marc; Lang Franziska....et alT-cell proliferation and generation of protective memory during chronic infections depend on Interleukin-7 (IL-7) availability and receptivity. Regulation of IL-7 receptor (IL-7R) expression and signalling are key for IL-7-modulated T-cell functions. Aberrant expression of soluble (s) and membrane-associated (m) IL-7R molecules is associated with development of autoim munity and immune failure in acquired immune deficiency syndrome (AIDS) patients. Here we investigated the role of IL-7/IL-7R on T-cell immunity in human tuberculosis. We per formed two independent case-control studies comparing tuberculosis patients and healthy contacts. This was combined with follow-up examinations for a subgroup of tuberculosis patients under therapy and recovery. Blood plasma and T cells were characterised for IL-7/ sIL-7R and mIL-7R expression, respectively. IL-7-dependent T-cell functions were deter mined by analysing STAT5 phosphorylation, antigen-specific cytokine release and by ana lysing markers of T-cell exhaustion and inflammation. Tuberculosis patients had lower soluble IL-7R (p < 0.001) and higher IL-7 (p < 0.001) plasma concentrations as compared to healthy contacts. Both markers were largely independent and aberrant expression normal ised during therapy and recovery. Furthermore, tuberculosis patients had lower levels ofmIL-7R in T cells caused by post-transcriptional mechanisms. Functional in vitro tests indi cated diminished IL-7-induced STAT5 phosphorylation and impaired IL-7-promoted cyto kine release of Mycobacterium tuberculosis-specific CD4+ T cells from tuberculosis patients. Finally, we determined T-cell exhaustion markers PD-1 and SOCS3 and detected increased SOCS3 expression during therapy. Only moderate correlation of PD-1 and SOCS3 with IL-7 expression was observed. We conclude that diminished soluble IL-7R and increased IL-7 plasma concentrations, as well as decreased membrane-associated IL-7R expression in T cells, reflect impaired T-cell sensitivity to IL-7 in tuberculosis patients. These findings show similarities to pathognomonic features of impaired T-cell functions and immune failure described in AIDS patients.
- ItemDiferential expression pattern of co-inhibitory molecules on CD4+ T cells in uncomplicated versus complicated malaria(Springer Nature, 2018) Abel Annemieke; Steeg Christiane; Owusu-Dabo Ellis; Aminkiah Francis; Addai-Mensah Otchere...et alThe immune response of malaria patients is a main factor influencing the clinical severity of malaria. A tight regulation of the CD4+ T cell response or the induction of tolerance have been proposed to contribute to protection from severe or clinical disease. We therefore compared the CD4+ T cell phenotypes of Ghanaian children with complicated malaria, uncomplicated malaria, asymptomatic Plasmodium falciparum (Pf) infection or no infection. Using flow cytometric analysis and automated multivariate clustering, we characterized the expression of the co-inhibitory molecules CTLA-4, PD-1, Tim-3, and LAG-3 and other molecules implicated in regulatory function on CD4+ T cells. Children with complicated malaria had higher frequencies of CTLA-4+ or PD-1+ CD4+ T cells than children with uncomplicated malaria. Conversely, children with uncomplicated malaria showed a higher proportion of CD4+ T cells expressing CD39 and Granzyme B, compared to children with complicated malaria. In contrast, asymptomatically infected children expressed only low levels of co-inhibitory molecules. Thus, different CD4+ T cell phenotypes are associated with complicated versus uncomplicated malaria, suggesting a two-sided role of CD4+ T cells in malaria pathogenesis and protection. Deciphering the signals that shape the CD4+ T cell phenotype in malaria will be important for new treatment and immunization strategies.
- ItemEfectiveness of school-based interventions for preventing tobacco smoking initiation among young people in low and middle-income countries: a systematic review protocol(BioMed Central, 2022) Logo Darlington Divine; Enuameh Yeetey; Owusu-Dabo Ellis; Adjei George; Singh Arti....et alBackground: Despite the commendable progress made globally in tobacco control, the world is falling short of achieving a 30% relative reduction in current tobacco use by 2025. The African region remains the least in the eforts in fghting the tobacco epidemic and is most exploited by the tobacco industry. Schools have been continuously used for over three decades as a setting for delivering youth smoking prevention programmes; however, the evidence of the efectiveness of those school-based interventions provides varying outcomes. Also, interventions that proved to be efective, in high-income countries (HICs), may not necessarily be efective in the African region as a result of cultural diferences and other contrasting factors. An existing systematic review that explored school-based tobacco prevention programmes among the youth in Afri‑ can countries from 2000 to 2016 showed partial efectiveness. This review will address the gap by updating the 2016 review to examine studies in LMICs to generate fndings to help target resources which have the potential to save lives by preventing smoking initiation among young people. Methods: The JBI methodology for systematic reviews of efectiveness will guide the conduct of this review. A comprehensive strategic search will be developed to retrieve both published and unpublished studies that evaluate school-based interventions to prevent tobacco smoking initiation among in-school young people in LMICs compared to non-intervention programmes. Published studies would be from databases such as MEDLINE via Ovid, CINAHL via EBSCO, Embase, PsycINFO, PsycEXTRA, and the Cochrane Central Register of Controlled Trials. Sources of grey literature would be ProQuest Dissertations and Theses, MedNar, EBSCO Open Dissertations, Open Access Theses and Disserta‑ tions, and Trove. The databases will be searched for published studies in the English language. The processes of study selection, critical appraisal, data extraction, and data synthesis will be in accordance with the JBI approach for reviews of efectiveness with a minimum of two reviewers at each stage. The primary outcome of the review will be the non-initiation of tobacco smoking by the youth. Discussion: The review will provide synthesized evidence on the efectiveness of school-based smoking initiation prevention among young people in LMICs. The fndings of the review would support policymakers and programme implementers to develop targeted interventions for efective tobacco control initiatives. Systematic review registration: PROSPERO CRD42021246206
- ItemHigh prevalence of antibiotic resistance in commensal Escherichia coli from healthy human sources in community settings(Springer Nature, 2021) Nji Emmanuel; Kazibwe Joseph; Owusu-Dabo Ellis; Hambridge Thomas; Joko Alia Carolyn.....et al; 0000-0003-4232-4292Antibiotic resistance is a global health crisis that requires urgent action to stop its spread. To counteract the spread of antibiotic resistance, we must improve our understanding of the origin and spread of resistant bacteria in both community and healthcare settings. Unfortunately, little attention is being given to contain the spread of antibiotic resistance in community settings (i.e., locations outside of a hospital inpatient, acute care setting, or a hospital clinic setting), despite some studies have consistently reported a high prevalence of antibiotic resistance in the community settings. This study aimed to investigate the prevalence of antibiotic resistance in commensal Escherichia coli isolates from healthy humans in community settings in LMICs. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we synthesized studies conducted from 1989 to May 2020. A total of 9363 articles were obtained from the search and prevalence data were extracted from 33 articles and pooled together. This gave a pooled prevalence of antibiotic resistance (top ten antibiotics commonly prescribed in LMICs) in commensal E. coli isolates from human sources in community settings in LMICs of: ampicillin (72% of 13,531 isolates, 95% CI: 65–79), cefotaxime (27% of 6700 isolates, 95% CI: 12–44), chloramphenicol (45% of 7012 isolates, 95% CI: 35–53), ciprofloxacin (17% of 10,618 isolates, 95% CI: 11–25), co-trimoxazole (63% of 10,561 isolates, 95% CI: 52–73), nalidixic acid (30% of 9819 isolates, 95% CI: 21–40), oxytetracycline (78% of 1451 isolates, 95% CI: 65–88), streptomycin (58% of 3831 isolates, 95% CI: 44–72), tetracycline (67% of 11,847 isolates, 95% CI: 59–74), and trimethoprim (67% of 3265 isolates, 95% CI: 59–75). Here, we provided an appraisal of the evidence of the high prevalence of antibiotic resistance by commensal E. coli in community settings in LMICs. Our findings will have important ramifications for public health policy design to contain the spread of antibiotic resistance in community settings. Indeed, commensal E. coli is the main reservoir for spreading antibiotic resistance to other pathogenic enteric bacteria via mobile genetic elements.
- Itemnjury rate and risk factors among small scale gold miners in Ghana(BioMed Central, 2019) Nakua Kweku Emmanuel; Owusu-Dabo Ellis; Newton Samuel; Koranteng Adofo; Otupiri Easmon; Donkor Peter; Mock CharlesBackground: To determine the potential risk factors for injury, estimate the annual injury rate and examine the safety perceptions, and use of personal protective equipment among small-scale gold miners in Ghana. Methods: A cross-sectional survey was carried out with 494 small-scale gold miners from four major mining districts in Ghana. A household-based approach was used to obtain a representative sample of miners. The study was conducted from June 2015 to August 2016. A systematic sampling technique was used to select households and recruit respondents to interview. Miners were asked about any mining related injury that they had sustained in the past year. A logistics regression model was employed to examine the association between risk factors and injury. Data were analyzed with STATA version 14.0. Results: The annual incidence rate of mining-related injury was 289 per 1000 workers. Injuries were mainly caused by machinery/tools 66(46.1%), followed by slip/falls 46(32.2%). The major risk factor for injury was underground work (adjusted odds ratio for injury 3.19; 95% CI = 1.42–7.20) compared with surface work. Higher education levels were protective, with adjusted odds ratios of 0.48 (95% CI = 0.24–0.99) for middle school education and 0.38 (95% CI 0.17–0.83) for secondary school compared with no schooling. Only 15(3.0%) of miners reported to have had safety training in the past year and 105(21.3%) indicated that there were safety regulations at their work place. A moderate number of workers reported using work boots 178(36.0%) and hand gloves 134(27.1%), but less than 10% of workers used other personal protective equipment. Conclusion: The annual injury incidence rate among small-scale gold miners is high. Potential targets for improving safety include increasing safety training, increasing use of personal protective equipment, and better understanding potential changes that can be made in the machinery and tools used in small-scale mining, which were associated with almost half of all injuries.
- ItemOrgan damage in sickle cell disease study (ORDISS): protocol for a longitudinal cohort study based in Ghana(BJM Open, 2017) Anie A Kofi; Paintsil Vivian; Ansong Daniel; Owusu-Dabo Ellis; Osei-Akoto Alex; Ohene-Frempong Kwaku....et alIntroduction Sickle cell disease is highly prevalent in Africa with a significant public health burden. Nonetheless, morbidity and mortality in sickle cell disease that result from the progression of organ damage is not well understood. The Organ Damage in Sickle Cell Disease Study (ORDISS) is designed as a longitudinal cohort study to provide critical insight into cellular and molecular pathogenesis of chronic organ damage for the development of future innovative treatment. Methods and analysis ORDISS aims to recruit children aged 0–15 years who attend the Kumasi Centre for Sickle Cell Disease based at the Komfo Anokye Teaching Hospital in Kumasi, Ghana. Consent is obtained to collect blood and urine samples from the children during specified clinic visits and hospitalisations for acute events, to identify candidate and genetic markers of specific organ dysfunction and end-organ damage, over a 3 year period. In addition, data concerning clinical history and complications associated with sickle cell disease are collected. Samples are stored in biorepositories and analysed at the Kumasi Centre for Collaborative Research in Tropical Medicine, Ghana and the Centre for Translational and International Haematology, University of Pittsburgh, USA. Appropriate statistical analyses will be performed on the data acquired. Ethics and dissemination Research ethics approval was obtained at all participating sites. Results of the study will be submitted for publication in peer-reviewed journals, and the key findings presented at national and international conferences.
- ItemRalstonia mannitolilytica sepsis: a case report(BioMed Central, 2019) Owusu Michael; Acheampong Godfred; Owusu-Dabo Ellis; Annan Augustina; Osei Isaac...et alBackground: Ralstonia mannitolilytica is an emerging opportunistic pathogen that is associated with severe disease, including septic shock, meningitis, and renal transplant infections. Reports on this pathogen are limited, however, especially on the African continent. Case presentation: A 2-year-old Akan child was presented to a hospital in the northeastern part of Ghana with a 1-week history of fever and chills. We identified Ralstonia mannitolilytica in her blood culture using both conventional and 16S ribosomal deoxyribonucleic acid (rDNA) techniques. The patient’s condition improved clinically upon treatment with cefuroxime. Conclusion: Our report highlights the potential of Ralstonia mannitolilytica to cause sepsis and thus emphasizes the need for improved laboratory diagnosis and evidence for use of appropriate antibiotics in rural settings of Africa, where presumptive treatment using antimicrobial agents is rife.
- ItemThe burden of drug resistance tuberculosis in Ghana; results of the First National Survey(PLOS ONE, 2021) Sylverken Angelina Augustina; Kwarteng Alexander; Arthur Agyeiwaa Rejoice; Owusu-Dabo Ellis; Bonsu Frank; Adu-Amoah Louis...et alResistance to Tuberculosis drugs has become a major threat to the control of tuberculosis (TB) globally. We conducted the first nation-wide drug resistance survey to investigate the level and pattern of resistance to first-line TB drugs among newly and previously treated sputum smear-positive TB cases. We also evaluated associations between potential risk factors and TB drug resistance. Using the World Health Organization (WHO) guidelines on conducting national TB surveys, we selected study participants from 33 health facilities from across the country, grouped into 29 clusters, and included them into the survey. Between April 2016 and June 2017, a total of 927 patients (859 new and 68 previously treated) were enrolled in the survey. Mycobacterium tuberculosis complex (MTBC) isolates were success fully cultured from 598 (65.5%) patient samples and underwent DST, 550 from newly diag nosed and 48 from previously treated patients. The proportion of patients who showed resistance to any of the TB drugs tested was 25.2% (95% CI; 21.8–28.9). The most frequent resistance was to Streptomycin (STR) (12.3%), followed by Isoniazid (INH) (10.4%), with Rifampicin (RIF), showing the least resistance of 2.4%. Resistance to Isoniazid and Rifampi cin (multi-drug resistance) was found in 19 (3.2%; 95% CI: 1.9–4.9) isolates. Prevalence of multidrug resistance was 7 (1.3%; 95% CI: 0.5–2.6) among newly diagnosed and 12 (25.0%; 95% CI: 13.6–39.6) among previously treated patients. At both univariate and multi variate analysis, MDR-TB was positively associated with previous history of TB treatment (OR = 5.09, 95% CI: 1.75–14.75, p = 0.003); (OR = 5.41, 95% CI: 1.69–17.30, p = 0.004). The higher levels of MDR-TB and overall resistance to any TB drug among previously treated patients raises concerns about adherence to treatment. This calls for strengthening
- ItemTobacco consumption and non-communicable diseases in Ghana; Identifying accentuating factors and further evidence from 2014 Ghana demographic and health survey(ELSEVIER, 2023) Brenyah Kwasi Joseph; Nonvignon Justice; Owusu-Dabo Ellis; Singh ArtiBackground: Non-communicable diseases such as hypertension, diabetes, strokes, cancers and chronic kidney conditions have caused disabilities and negatively impacted on eco nomic development. While greater efforts of controlling these non-communicable diseases are clinically motivated, the non-clinical factors such as behavioural lifestyle and the as sociated accentuating factors have not been given due attention. It has been established elsewhere that, tobacco use which is a risk factor for non-communicable diseases occur rence is influenced by individual’s residential status, educational status, occupational sta tus, income level and access to media projections. This study therefore sought to identify associations between accentuating factors and tobacco use and its implications for the oc currence of non-communicable diseases prevalent in Ghana. Methods: This was a mixed method study involving in part, use of secondary data from the Ghana Demographic and Health Survey 2014 with a sample of 4,122 respondents and primary qualitative interviews of 32 respondents respectively, from 4 Regions of Ghana. Descriptive statistics, probit regression and content thematic analysis were used for data analysis for both the quantitative and qualitative arms respectively. Results: The study found that, there was statistically significant association between ed ucational status and tobacco use [X2 (5, 4,123)=164.5619; p = 0.000], income levels and tobacco use [X2 (7, 4,123)=68.5615; p = 0.001), occupational status and tobacco use [X2 (8, 4,123)=195.6919; p = 0.000], residential status and tobacco [X2 (3, 4,134) = 82.7824; p = 0.000)] and finally, access to mass media and tobacco use [X2 (2, 4,134)= 1.2352, p = 0.009]. Again, the regression result shows that, the accentuating factors determine about 51% (50.579) of the tobacco use by individuals in the relation [R2 = 0.305, F(17, 4,077) = 50.579, p = 0.000]. Moreover, 62.4 percent of females were less likely to smoke
- ItemTransmission of SARS‑CoV‑2 in northern Ghana: insights from whole‑genome sequencing(SPRINGER, 2021) Sylverken Angelina Augustina; El‑Duah Philip; Owusu-Dabo Ellis; Schneider Julia; Owusu Michael..Following the detection of the frst imported case of COVID-19 in the northern sector of Ghana, we molecularly charac terized and phylogenetically analysed sequences, including three complete genome sequences, of severe acute respiratory syndrome coronavirus 2 obtained from nine patients in Ghana. We performed high-throughput sequencing on nine samples that were found to have a high concentration of viral RNA. We also assessed the potential impact that long-distance transport of samples to testing centres may have on sequencing results. Here, two samples that were similar in terms of viral RNA concentration but were transported from sites that are over 400 km apart were analyzed. All sequences were compared to previous sequences from Ghana and representative sequences from regions where our patients had previously travelled. Three complete genome sequences and another nearly complete genome sequence with 95.6% coverage were obtained. Sequences with coverage in excess of 80% were found to belong to three lineages, namely A, B.1 and B.2. Our sequences clustered in two diferent clades, with the majority falling within a clade composed of sequences from sub-Saharan Africa. Less RNA fragmentation was seen in sample KATH23, which was collected 9 km from the testing site, than in sample TTH6, which was collected and transported over a distance of 400 km to the testing site. The clustering of several sequences from sub-Saharan Africa suggests regional circulation of the viruses in the subregion. Importantly, there may be a need to decentralize testing sites and build more capacity across Africa to boost the sequencing output of the subregion.