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Featured researches published by Richard K. Gyasi.


Malaria Journal | 2007

Cerebrospinal fluid and serum biomarkers of cerebral malaria mortality in Ghanaian children

Henry B Armah; Nana O. Wilson; Bismark Sarfo; Michael Powell; Vincent C. Bond; Winston A. Anderson; Andrew A. Adjei; Richard K. Gyasi; Yao Tettey; Edwin K. Wiredu; Jon Eric Tongren; Venkatachalam Udhayakumar; Jonathan K Stiles

BackgroundPlasmodium falciparum can cause a diffuse encephalopathy known as cerebral malaria (CM), a major contributor to malaria associated mortality. Despite treatment, mortality due to CM can be as high as 30% while 10% of survivors of the disease may experience short- and long-term neurological complications. The pathogenesis of CM and other forms of severe malaria is multi-factorial and appear to involve cytokine and chemokine homeostasis, inflammation and vascular injury/repair. Identification of prognostic markers that can predict CM severity will enable development of better intervention.MethodsPostmortem serum and cerebrospinal fluid (CSF) samples were obtained within 2–4 hours of death in Ghanaian children dying of CM, severe malarial anemia (SMA), and non-malarial (NM) causes. Serum and CSF levels of 36 different biomarkers (IL-1β, IL-1ra, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-12 (p70), IL-13, IL-15, IL-17, Eotaxin, FGF basic protein, CRP, G-CSF, GM-CSF, IFN-γ, TNF-α, IP-10, MCP-1 (MCAF), MIP-1α, MIP-1β, RANTES, SDF-1α, CXCL11 (I-TAC), Fas-ligand [Fas-L], soluble Fas [sFas], sTNF-R1 (p55), sTNF-R2 (p75), MMP-9, TGF-β1, PDGF bb and VEGF) were measured and the results compared between the 3 groups.ResultsAfter Bonferroni adjustment for other biomarkers, IP-10 was the only serum biomarker independently associated with CM mortality when compared to SMA and NM deaths. Eight CSF biomarkers (IL-1ra, IL-8, IP-10, PDGFbb, MIP-1β, Fas-L, sTNF-R1, and sTNF-R2) were significantly elevated in CM mortality group when compared to SMA and NM deaths. Additionally, CSF IP-10/PDGFbb median ratio was statistically significantly higher in the CM group compared to SMA and NM groups.ConclusionThe parasite-induced local cerebral dysregulation in the production of IP-10, 1L-8, MIP-1β, PDGFbb, IL-1ra, Fas-L, sTNF-R1, and sTNF-R2 may be involved in CM neuropathology, and their immunoassay may have potential utility in predicting mortality in CM.


Annals of Tropical Medicine and Parasitology | 2005

High-level cerebellar expression of cytokines and adhesion molecules in fatal, paediatric, cerebral malaria

Henry B Armah; A. K. Dodoo; Edwin K. Wiredu; Jonathan K. Stiles; Andrew A. Adjei; Richard K. Gyasi; Yao Tettey

Abstract Although the roles played by systemic tumour necrosis factor (TNF) and interleukin 1β (IL-1β), and their upregulation of intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1) and E-selectin, in the pathogenesis of human cerebral malaria (CM) are well established, the role of local cytokine release, in the brain, remains unclear. Immunohistochemistry was therefore used to compare the expression of ICAM-1, VCAM-1, E-selectin, IL-1β, TNF and transforming growth factor β (TGF-β) at light-microscope level, in cryostat sections of cerebral, cerebellar and brainstem tissues collected, post-mortem, from Ghanaian children. Among the 21 children investigated were 10 cases of CM, five of severe malarial anemia (SMA), one of purulent bacterial meningitis (PBM), two of non-central-nervous-system infection (NCNSI) and three children who had no infection (NI) when they died. Parasitised erythrocytes were detected in all of the sections from the cases of fatal malaria (CM and SMA), and sequestered leucocytes were present in most of the sections from the CM cases (but none of the sections from the SMA cases). Significantly elevated vascular expression of all three adhesion molecules investigated was detected in the brains of the 15 cases of fatal malaria and one of the cases of NCNSI (a child with Salmonella septicaemia), and in the malaria cases this showed highly significant co-localization with the areas of erythrocyte sequestration. In terms of the levels of expression of ICAM-1, VCAM-1 and E-selectin, there were, however, negligible differences between the CM and SMA cases. Although TGF-β showed intravascular and perivascular distribution in all the subjects, its expression was most intense in the PBM case and the CM group. Only in the sections from the PBM and CM cases did TNF and IL-1β show prominent brain parenchymal staining, in addition to the intravascular and perivascular staining seen in all subjects. The highest observed expression of each of the six antigens studied was in the cerebellar sections of the malaria cases. Endothelial activation in the brain therefore appears to be a feature of fatal malaria and Salmonella sepsis, and in cases of fatal malaria is closely associated with leucocyte sequestration. In the present study, IL-1β and TNF were only up-regulated in the brains of children with neurodegenerative lesions, whereas TGF-β was present in all cases.


Molecular and Biochemical Parasitology | 2008

Soluble factors from Plasmodium falciparum-infected erythrocytes induce apoptosis in human brain vascular endothelial and neuroglia cells

Nana O. Wilson; Ming-Bo Huang; Winston A. Anderson; Vincent C. Bond; Michael Powell; Winston E. Thompson; Henry B Armah; Andrew A. Adjei; Richard K. Gyasi; Yao Tettey; Jonathan K. Stiles

The severity of malaria is multi-factorial. It is associated with parasite-induced alteration in pro-inflammatory and anti-inflammatory cytokine and chemokine levels in host serum and cerebrospinal fluid. It is also associated with sequestration and cytoadherence of parasitized erythrocytes (pRBCs) in post-capillary venules and blood-brain barrier (BBB) dysfunction. The role of these factors in development of vascular injury and tissue damage in malaria patients is unclear. While some studies indicate a requirement for pRBC adhesion to vascular endothelial cells (ECs) in brain capillaries to induce apoptosis and BBB damage, others show no role of apoptosis resulting from adhesion of pRBC to EC. In the present study, the hypothesis that soluble factors from Plasmodium falciparum-infected erythrocytes induce apoptosis in human brain vascular endothelial (HBVEC) and neuroglia cells (cellular components of the BBB) was tested. Apoptotic effects of parasitized (pRBC) and non-parasitized erythrocyte (RBC) conditioned medium on HBVEC and neuroglia cells were determined in vitro by evaluating nuclear DNA fragmentation (TUNEL assay) in cultured cells. Soluble factors from P. falciparum-infected erythrocytes in conditioned medium induced extensive DNA fragmentation in both cell lines, albeit to a greater extent in HBVEC than neuroglia, indicating that extended exposure to high levels of these soluble factors in serum may be associated with vascular, neuronal and tissue injury in malaria patients.


American Journal of Tropical Medicine and Hygiene | 2011

Intermittent preventive treatment with sulfadoxine-pyrimethamine against malaria and anemia in pregnant women.

Nana O. Wilson; Fatou K. Ceesay; Samuel A. Obed; Andrew A. Adjei; Richard K. Gyasi; Patricia Rodney; Yassa Ndjakani; Winston A. Anderson; Naomi W. Lucchi; Jonathan K. Stiles

The effectiveness of intermittent preventive treatment during pregnancy with sulfadoxine-pyrimethamine (IPTp-SP) against malaria and anemia is unclear because of the spread of SP-resistant Plasmodium falciparum. This study evaluates the effectiveness of IPTp-SP among pregnant women attending the antenatal clinic at Korle-Bu Teaching Hospital in Accra, Ghana. A cross-sectional study comparing malaria and anemia prevalence among pregnant women using IPTp-SP with non-IPTp-SP users was conducted during June-August 2009. A total of 363 pregnant women (202 of IPTp users and 161 non-IPTp users) were recruited. A total of 15.3% of IPTp users had malaria compared with 44.7% of non-IPTp users (P < 0.001). A total of 58.4% of non-IPTp users were anemic compared with 22.8% of IPTp users (P < 0.001). When we controlled for other variables, the difference in the prevalence of malaria (odds ratio = 0.18, 95% confidence interval = 0.08-0.37) and anemia (odds ratio = 0.20, 95% confidence interval = 0.12-0.34) remained significant. The recommended IPTp-SP regimen is useful in preventing malaria and anemia among pregnant women in Ghana.


The Journal of Infectious Diseases | 2013

Placental Malaria and the Risk of Malaria in Infants in a High Malaria Transmission Area in Ghana: A Prospective Cohort Study

Kwaku Poku Asante; Seth Owusu-Agyei; Matthew Cairns; Daniel Dodoo; Ellen Abrafi Boamah; Richard K. Gyasi; George Adjei; Ben Gyan; Akua Agyeman-Budu; Theophilus Dodoo; Emmanuel Mahama; Nicholas Amoako; David Dosoo; Kwadwo A. Koram; Brian Greenwood; Daniel Chandramohan

BACKGROUND Whether the risk of malaria is increased in infants born to mothers who experience malaria during pregnancy is uncertain. METHODS  We investigated malaria incidence among an infant cohort born to 355 primigravidae and 1500 multigravidae with or without placental malaria (PM) in a high malaria transmission area of Ghana. PM was assessed using placental histology. RESULTS The incidence of all episodes of malaria parasitemia or clinical malaria was very similar among 3 groups of infants: those born to multigravidae without PM, multigravidae with PM, and primigravidae with PM. Infants born to primigravidae without PM experienced a lower incidence of malaria parasitemia or clinical malaria than the other 3 groups: adjusted hazard ratio, 0.64 (95% confidence interval [CI], .48-.86, P < .01) and 0.60 (95% CI, .43-.84, P < .01), respectively. The incidence of malaria parasitemia or clinical malaria was about 2 times higher in most poor infants compared to least poor infants. CONCLUSIONS There was no suggestion that exposure to PM directly increased incidence of malaria among infants of multigravidae. In our study area, absence of placental malaria in primigravidae is a marker of low exposure, and this probably explains the lower incidence of malaria-related outcomes among infants of PM-negative primigravidae.


American Journal of Tropical Medicine and Hygiene | 2012

Pregnancy outcomes among patients with sickle cell disease at Korle-Bu Teaching Hospital, Accra, Ghana: retrospective cohort study.

Nana O. Wilson; Fatou K. Ceesay; Jacqueline M. Hibbert; Adel Driss; Samuel A. Obed; Andrew A. Adjei; Richard K. Gyasi; Winston A. Anderson; Jonathan K. Stiles

Pregnancy in sickle cell disease (SCD) patients is associated with increased risk of maternal and fetal mortality. This study determines pregnancy outcomes among women with SCD delivering at Korle-Bu Teaching Hospital, Accra, Ghana. Nine hundred sixty (960) medical records of pregnant women (131 HbSS, 112 HbSC, and 717 comparison group) from 2007 to 2008 were reviewed. The HbSS women were at increased risk of eclampsia (adjusted odds ratio [AOR] = 10.56, 95% confidence interval [CI] = 3.60-30.96, P < 0.001), intrauterine growth restriction (AOR = 4.00, 95% CI = 1.38-11.64, P = 0.011), and placenta previa (AOR = 22.03, 95% CI = 9.87-49.14, P < 0.001) compared with the comparison group. The HbSC women had increased risk for intrauterine fetal death (AOR = 3.38, 95% CI = 1.15-9.96, P = 0.027) and decreased risk of delivering low birth weight babies (AOR = 0.21, 95% CI = 0.06-0.73, P = 0.014). Women with SCD in Ghana are at a greater risk of morbidity and mortality in pregnancy compared with women without hemoglobinopathies. Improved maternal and fetal outcomes in Ghanaian women with SCD can be achieved through effective intervention by health care providers with thorough knowledge about predisposing factors toward adverse outcomes.


Breast Journal | 2015

Triple-negative breast cancer in Ghanaian women: The Korle Bu Teaching Hospital experience

Edmund Muonir Der; Richard K. Gyasi; Yao Tettey; Lawrence Edusei; Marcel T. Bayor; Evelyn Jiagge; Mawuli Gyakobo; Sofia D. Merajver; Lisa A. Newman

Breast cancers that have negative or extremely low expression of estrogen receptor and progesterone receptor and non‐amplification of human epidermal growth factor receptor‐2 (HER2)/neu are termed triple‐negative breast cancer (TNBC). The majority of TNBC tumors belong to the biologically aggressive basal subtype, and they cannot be managed with targeted endocrine or anti‐HER2/neu agents. In western, high resource environments, risk factors for TNBC include younger age at diagnosis and hereditary susceptibility. Women of African ancestry in the United States and in continental Africa have higher frequencies of TNBC, prompting speculation that this risk may have an inherited basis and may at least partially explain breast cancer survival disparities related to racial/ethnic identity. Efforts to document and confirm the breast cancer burden of continental Africa have been hampered by the limited availability of registry and immunohistochemistry resources. Our goal was to evaluate the breast cancers diagnosed in one of the largest health care facilities in western Africa, and to compare the frequencies as well as risk factors for TNBC versus non‐TNBC in this large referral tertiary hospital. The Korle Bu Teaching Hospital is affiliated with the University of Ghana and is located in Accra, the capital of Ghana. We conducted an institutional, Department of Pathology‐based review of the breast cancer cases seen at this facility for the 2010 calendar year, and for which histopathologic specimens were available. The overall study population of 223 breast cancer cases had a median age of 52.4 years, and most had palpable tumors larger than 5 cm in diameter. More than half were TNBC (130; 58.3%). We observed similar age‐specific frequencies, distribution of stage at diagnosis and tumor grade among cases of TNBC compared to cases of non‐TNBC. Ghanaian breast cancer patients tend to have an advanced stage distribution and relatively younger age at diagnosis compared to Caucasian Americans and African Americans. The triple‐negative molecular marker pattern was the most common subtype of breast cancer seen among this sample of Ghanaian women, regardless of age, tumor grade, or stage of diagnosis. Research into the molecular pathogenesis of TNBC may help elucidate the reasons for its increased prevalence among women with African ancestry.


International Journal of Dermatology | 2017

Use of skin-lightening products among selected urban communities in Accra, Ghana.

Margaret Lartey; Francis D. Krampa; Mubarak Abdul-Rahman; Naa Larteley Quarcoo; Phaedra Yamson; Paa Gyasi Hagan; Yao Tettey; Richard K. Gyasi; Andrew A. Adjei

The practice of skin lightening has been reported from North America, Europe, Asia, and Africa. In literature, some prevalence rates exceed 50%, and both sexes are involved. Common agents used include hydroquinone, mercury, corticosteroids, and caustic agents. The agents are easily accessible and affordable with very little regulation. Cutaneous and systemic side effects occur but do not appear to be a deterrent, as the notion of light skin as a surrogate for beauty is strong. In Ghana, anecdotal reports of high bleaching rates among certain urban communities resulted in a study supported by the Food and Drugs Authority to determine various facets of this practice.


American Journal of Clinical Pathology | 2013

Breast Cancer in Ghanaian Women

Der Muonir Edmund; S. B. Naaeder; Yao Tettey; Richard K. Gyasi

OBJECTIVES To evaluate breast cancer in Ghanaian women and to compare these findings with those of previous studies by using histopathologic data. METHODS A review of all breast cancer specimens from January 2005 through December 2009 in our institution was conducted. RESULTS Of 4,109 female breast specimens reviewed, 1,342 (32.7%) were malignant. Mean (SD) patient age was 50.3 (13.3) years, and mean size of the primary tumors was 4.5 cm. Eighteen (1.3%) specimens were malignant phyllodes tumors. Significant positive associations were found between size of the primary tumor and histologic type (P = .01), histologic grade (P = .001), nodal involvement (P < .001), and TNM stage (P < .001). CONCLUSIONS More than 3 decades after the first publication of breast cancer in Ghanaian women, patients are still presenting with large clinically and histologically advanced invasive cancers.


The Pan African medical journal | 2015

Epidemiology of Helicobacter pylori infection in dyspeptic Ghanaian patients

Timothy N. Archampong; Richard H. Asmah; Edwin K. Wiredu; Richard K. Gyasi; Kofi Nyaako Nkrumah; Kumar Rajakumar

Introduction Helicobacter pylori is a gram-negative urease-producing bacterium causally linked with gastritis, peptic ulcer disease and gastric adenocarcinoma. Infection is more frequent and acquired at an earlier age in developing countries compared to European populations. The incidence of Helicobacter pylori infection in dyspeptic Ghanaian patients was 75.4%. However, epidemiological factors associated with infection vary across populations. Methods This study used a cross-sectional design to consecutively sample dyspeptic patients at the Endoscopy Unit of the Korle-Bu Teaching Hospital, Accra between 2010 and 2012. The study questionnaire elicited their epidemiological clinical characteristics. Helicobacter pylori infection was confirmed by rapid-urease examination of antral biopsies at upper Gastro-intestinal endoscopy. Results The sample population of dyspeptic patients attending the Endoscopy Unit for upper GI endoscopy yielded 242 patients of which 47.5% were females. The age distribution of H. pylori-infection was even across most age – groups, ranging from 69.2% (61 – 70) years to 80% (21 – 30) years. Helicobacter pylori prevalence decreased across areas mapping to the three residential classes in accordance with increasing affluence with rural areas having the highest prevalence. The unemployed and patients in farming had relatively high Helicobacter pylori infection rates of 92.3% and 91.7% respectively. Conclusion Helicobacter pylori is endemic in Ghana but the persistently high prevalence across age groups despite significant community anti-microbial use suggests likely re-crudescence or re-infection from multiple sources in a developing country. Socio-cultural factors such as residential class and farming may be facilitating factors for its continued prevalence.

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