Browsing by Author "Akao, N."

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Administrative practices of health professionals and use of artesunate-amodiaquine by community members for treating uncomplicated malaria in southern Ghana: implications for artemisinin-based combination therapy deployment
(Tropical Medicine and International Health, 2011) Kwansa-Bentum, B.; Ayi, I.; Suzuki, T.; Otchere, J.; Kumagai, T.; Anyan, W.K.; Asahi, H.; Akao, N.; Wilson, M.D.; Boakye, D.A.; Ohta, N.
Objective: To investigate the use of artemisinin-based combination and monotherapy by community members and the administrative practices of health professionals in treating malaria in Ghana. Method: This study is a community-based cross-sectional survey in 11 rural and urban areas in southern Ghana. Using the interviewer method, close-ended questionnaires were administered to community members. Similar questionnaires were also administered in health facilities, community pharmacies and licensed chemical shops. Results: A total of 1085 individuals comprising 959 non-health professionals and 126 health professionals were interviewed. Fifty-seven per cent of the community members visit pharmacies/drug stores as the first point of call when they suspect malaria. According to the participating drug sellers, artemether-lumefantrine (AL) is the most prescribed/sold anti-malarial drug (59.2%), followed by dihydroartemisinin (35%), sulfadoxine-pyrimethamine (33.0%) and artesunate-amodiaquine (AS-AQ) (27.2%). The majority of customers who visit pharmacies or drug stores without prescription have their anti-malarial drug selected by the shop attendant; in situations like that, dihydroartemisinin and artesunate monotherapies are sold just as AS-AQ and AL. Chloroquine is still sold by some drug vendors, 5years after its proscription. Conclusion: Whereas the use of AS-AQ and AL are acceptable, the frequent use of dihydroartemisinin and artesunate monotherapy threatens the future of ACTs.
Basophil depletion downregulates Schistosoma mansoni egg-induced granuloma formation
(Parasitology International, 2013-12) Anyan, W.K.; Seki, T.; Kumagai, T.; Obata-Ninomiya, K.; Furushima-Shimogawara, R.; Kwansa-Bentum, B.; Akao, N.; Bosompem, K.M.; Boakye, D.A.; Wilson, M.D.; Karasuyama, H.; Ohta, N.
Granuloma formation around parasite eggs during schistosomal infection is considered to be controlled by Th2 cytokines. However, it is still controversial which cell populations are responsible for the host Th2 cytokine-dependent granuloma formation. Basophils have recently attracted attention because of their ability to produce large amounts of IL-4. Therefore, we investigated whether basophils play an essential role in the induction of granuloma formation induced by Schistosoma mansoni eggs. Together with our previous observation that basophil numbers increased markedly in the spleen at 7. weeks postinfection, immunohistochemical staining using anti-mMCP8 monoclonal antibody (mAb) showed basophil infiltration in the granulomatous lesions formed around parasite eggs. To examine the roles of basophils more directly, we treated mice with anti-CD200R3 mAb to deplete basophils. Depletion of basophils resulted in a reduction of basophil number with concomitant downregulation of egg granuloma formation at 7. weeks postinfection. Moreover, we observed a significant reduction in the size of egg granulomas formed in basophil-depleted mice in the pulmonary granuloma model. Taken together, these findings indicated that basophils are essential for S. mansoni egg-induced granuloma formation, and this may serve as a novel therapeutic target in ameliorating the pathology of schistosomiasis. © 2013 Elsevier Ireland Ltd.
Development of membrane-based tests for the detection of urinary antigens and antibodies in human toxoplasmosis: preliminary studies in Ghanaian patients.
(preliminary studies in Ghanaian patients, 2005) Ayi, I.; Akao, N.; Bosompem, K.M.; Akafo, S.K.; Clarke, J.; Nyador, L.; Apea-Kubi, K.A.; Fujita, K.
Two membrane-based ELISA systems were used in detecting Toxoplasma antigens and anti-Toxoplasma antibodies in urine samples collected from 54 ophthalmology (22 suggestive active and 32 suggestive past infection) patients and 26 pregnant women attending obstetrics/gynaecology clinic (OGP), suspected of toxoplasmosis by eye examination, past medical records and questionnaire, respectively, in Ghana from mid-February to April 2002. The antigen detecting ELISA was able to demonstrate antigen in 100% (22/22) ophthalmology (active infection) and 62.5% (20/32) ophthalmology (past infection) patients, and 42% (11/26) of OGP which included 3 that were sero-negative prior to and during this study, giving an overall prevalence of 66.3% (53/80). The urinary antigen positive samples also included 6 that were negative for both the Dye Test (DT) and latex agglutination test (LAT). Antigen was not detected in the urine of 22 normal (sero-negative for antibodies to Toxoplasma) individuals. The membrane-based urinary antibody detecting sandwich ELISA also detected anti-Toxoplasma antibodies in 100% (22/22) of ophthalmology (active infection) and 81.3% (26/32) of ophthalmology (past infection) patients, a total of 89% (48/54); and 80.8% (21/26) of OGP with an overall prevalence of 86.3% (69/80), including 7 ophthalmology patients' samples that were sero-negative for both DT and LAT. Antibody sero-positivity of the samples was determined by DT as 87% (47/54) in ophthalmology patients and 73.1% (19/26) in pregnant women, LAT as 85.2% (46/54) and 65.4% (17/26), and an overall prevalence as 82.5% (66/80) and 78.8% (63/80), respectively. The membrane-based ELISA systems appear promising but need to be investigated further for its efficacy as reliable diagnostic tests.
Plasmodium falciparum isolates from southern Ghana exhibit polymorphisms in the SERCA-type PfATPase6 though sensitive to artesunate in vitro
(2011-07-11) Kwansa-Bentum, B.; Ayi, I.; Suzuki, T.; Otchere, J.; Kumagai, T.; Anyan, W.K.; Osei, J.H.N.; Asahi, H.; Ofori, M.F.; Akao, N.; Wilson, M.D.; Boakye, D.A.; Ohta, N.
Abstract Background In 2005, Ghana replaced chloroquine with artemisinin-based combination therapy as the first-line treatment for uncomplicated malaria. The aim of this work was to determine for the first time, polymorphisms in the putative pfATPase6 and pftctp, pfmdr1, pfcrt genes in Ghanaian isolates, particularly at a time when there is no report on artemisinin resistance in malaria parasites from Ghana. The sensitivity of parasite isolates to anti-malaria drugs were also evaluated for a possible association with polymorphisms in these genes. Methods The prevalence of point mutations in the above Plasmodium falciparum genes were assessed from filter-paper blood blot samples by DNA sequencing. In vitro drug sensitivity test was carried out on some of the blood samples from volunteers visiting hospitals/clinics in southern Ghana using a modified version of the standard WHO Mark III micro-test. Results All successfully tested parasite isolates were sensitive to artesunate; while 19.4%, 29.0% and 51.6% were resistant to quinine, amodiaquine and chloroquine respectively. The geometric mean of IC50 value for artesunate was 0.73 nM (95% CI, 0.38-1.08), amodiaquine 30.69 nM (95% CI, 14.18-47.20) and chloroquine 58.73 nM (95% CI, 38.08-79.38). Twenty point mutations were observed in pfATPase6 gene, with no L263E and S769N. All mutations found were low in frequency, except D639G which was observed in about half of the isolates but was not associated with artesunate response (p = 0.42). The pftctp gene is highly conserved as no mutation was observed, while CVIET which is chloroquine-resistant genotype at codon 72-76 of the pfcrt gene was identified in about half of the isolates; this was consistent with chloroquine IC50 values (p = 0.001). Mutations were present in pfmdr1 gene but were not associated with artemisinin response (p = 1.00). Conclusion The pfATPase6 gene is highly polymorphic with D639G appearing to be fixed in Ghanaian isolates. These may just be spontaneous mutations as all parasite isolates that were tested displayed satisfactory in vitro response to artesunate. However, there is no improvement in susceptibility of the parasites to chloroquine five years after its proscription.
Plasmodium falciparum isolates from southern Ghana exhibit polymorphisms in the SERCA-type PfATPase6 though sensitive to artesunate in vitro
(Malaria Journal, 2011) Kwansa-Bentum, B.; Ayi, I.; Suzuki, T.; Otchere, J.; Kumagai, T.; Anyan, W.K.; Osei, J.H.N.; Asahi, H.; Ofori, M.F.; Akao, N.; Wilson, M.D.; Boakye, D.A.; Ohta, N.
BACKGROUND: In 2005, Ghana replaced chloroquine with artemisinin-based combination therapy as the first-line treatment for uncomplicated malaria. The aim of this work was to determine for the first time, polymorphisms in the putative pfATPase6 and pftctp, pfmdr1, pfcrt genes in Ghanaian isolates, particularly at a time when there is no report on artemisinin resistance in malaria parasites from Ghana. The sensitivity of parasite isolates to anti-malaria drugs were also evaluated for a possible association with polymorphisms in these genes. METHODS: The prevalence of point mutations in the above Plasmodium falciparum genes were assessed from filter-paper blood blot samples by DNA sequencing. In vitro drug sensitivity test was carried out on some of the blood samples from volunteers visiting hospitals/clinics in southern Ghana using a modified version of the standard WHO Mark III micro-test. RESULTS: All successfully tested parasite isolates were sensitive to artesunate; while 19.4%, 29.0% and 51.6% were resistant to quinine, amodiaquine and chloroquine respectively. The geometric mean of IC50 value for artesunate was 0.73 nM (95% CI, 0.38-1.08), amodiaquine 30.69 nM (95% CI, 14.18-47.20) and chloroquine 58.73 nM (95% CI, 38.08-79.38). Twenty point mutations were observed in pfATPase6 gene, with no L263E and S769N. All mutations found were low in frequency, except D639G which was observed in about half of the isolates but was not associated with artesunate response (p = 0.42). The pftctp gene is highly conserved as no mutation was observed, while CVIET which is chloroquine-resistant genotype at codon 72-76 of the pfcrt gene was identified in about half of the isolates; this was consistent with chloroquine IC50 values (p = 0.001). Mutations were present in pfmdr1 gene but were not associated with artemisinin response (p = 1.00). CONCLUSION: The pfATPase6 gene is highly polymorphic with D639G appearing to be fixed in Ghanaian isolates. These may just be spontaneous mutations as all parasite isolates that were tested displayed satisfactory in vitro response to artesunate. However, there is no improvement in susceptibility of the parasites to chloroquine five years after its proscription.
Schistosome eggs have a direct role in the induction of basophils capable of a high level of IL-4 production: Comparative study of single- and bisexual infection of Schistosoma mansoni in vivo
(University of Ghana, 2010) Anyan, W.K.; Kumagai, T.; Rieko, F.; Shimogawara, F.K.; Seki, T.; Akao, N.; Obata, K.; Kwansa-Bentum, B.; Bosompem, K.M.; Boakye, D.A.; Wilson, M.; Karasuyama, H.; Ohta, N.
Immunobiological roles of schistosome eggs during murine experimental infection were investigated with special reference to the induction of basophilic leukocytes. After single- or bisexual infection with Schistosoma mansoni in BALB⁄c mice, splenomegaly and liver granulomas were observed only in bisexual infection in parallel with deposition of mature parasite eggs. Comparison of the kinetics of basophil response revealed a marked increase in number in the bone marrow of mice with bisexual infection at the 7th week post infection as opposed to a marginal increase in single- sex infections. In the spleen, bimodal response was observed in the basophil responses; a small but repeatable peak at the 4th week after infection, increasing again at the 8th week, which corresponded to the initiation and maturation of parasite eggs in the affected organs of infected mice. The same time course was observed for IL-4 production by the splenocytes from mice of bisexual infection. To obtain more concrete evidence of the role of eggs in the induction of basophils, we tested using the intravenous egg injection model. Injection of eggs induced basophilia, and it was accompanied by the up-regulation of IL-4 production in splenocytes from the 8th day. Basophils induced in this model showed a high level of IL-4 production confirmed by flow cytometry, while faint levels of IL-4 production were observed for CD4+ T cells at this time point. In addition, we demonstrate that egg deposition is the trigger of basophil induction and activation in the murine experimental model of S. mansoni infection, which might play an essential role in the initiation of Th1⁄2 conversion during the course of S. mansoni infection in vivo.
Schistosome eggs have a direct role in the induction of basophils capable of a high level of IL-4 production: Comparative study of single- and bisexual infection of Schistosoma mansoni in vivo
(International Journal of Tropical Insect Science, 2010) Anyan, W.K.; Kumagai, T.; Rieko, F.; Shimogawara, F.K.; Seki, T.; Akao, N.; Obata, K.; Kwansa-Bentum, B.; Bosompem, K.M.; Boakye, D.A.; Wilson, M.; Karasuyama, H.; Ohta, N.
Immunobiological roles of schistosome eggs during murine experimental infection were investigated with special reference to the induction of basophilic leukocytes. After single- or bisexual infection with Schistosoma mansoni in BALB⁄c mice, splenomegaly and liver granulomas were observed only in bisexual infection in parallel with deposition of mature parasite eggs. Comparison of the kinetics of basophil response revealed a marked increase in number in the bone marrow of mice with bisexual infection at the 7th week post infection as opposed to a marginal increase in single- sex infections. In the spleen, bimodal response was observed in the basophil responses; a small but repeatable peak at the 4th week after infection, increasing again at the 8th week, which corresponded to the initiation and maturation of parasite eggs in the affected organs of infected mice. The same time course was observed for IL-4 production by the splenocytes from mice of bisexual infection. To obtain more concrete evidence of the role of eggs in the induction of basophils, we tested using the intravenous egg injection model. Injection of eggs induced basophilia, and it was accompanied by the up-regulation of IL-4 production in splenocytes from the 8th day. Basophils induced in this model showed a high level of IL-4 production confirmed by flow cytometry, while faint levels of IL-4 production were observed for CD4+ T cells at this time point. In addition, we demonstrate that egg deposition is the trigger of basophil induction and activation in the murine experimental model of S. mansoni infection, which might play an essential role in the initiation of Th1⁄2 conversion during the course of S. mansoni infection in vivo.
A study on amoebiasis as an opportunistic infection in HIV/AIDS patients at Korle-Bu Teaching Hospital
(Ghana Journal of Allied Health Sciences 1(2):35-42, 2007) Ayi, I.; Boateng, N.A.D.; Ayeh-Kumi, P.F.; Sagoe, K.; Asmah, R.H.; Akao, N.
Background: The immuno-compromised state of HN / AIDS patients makes them susceptible to various infections. Amoebiasis, caused by Entamoeba histolytica is believed to be an opportunistic infection in HIV/AIDS patients. However in Ghana there is no data to ascertain this assertion. Objective: To determine the opportunistic status of amoebiasis in HN / AIDS patients through determination of amoebic antibody sero-prevalence among diarrhoea and non-diarrhoea patients in relation to their blood CD4 + cell count. Study design and methodology: A sample size of 95 HN patients consisting of 43 non-diarrhoea and 52 diarrhoea patients were involved. They constituted 65 females and 30 males aged 20 to 60 years old. A rapid test kit, INSTANTTMCHEK-amoeba was used to determine the presence of anti-E. histolytica antibodies in patients' sera. Their blood CD4+ cell count was also determined using a FACS counter. Results were analyzed by using the Chi square test statistic with a 95% confidence limit and a significant level of 0.05, to determine the significant difference between anti E. histolytica antibodies positive in diarrhoea and non-diarrhoea HIV patients. Results: The overall prevalence of anti-E. histolytica antibodies in the study population was 13.7%. About 77.0% of these had low CD4+ cell count. The highest anti-E. histolytica antibody prevalence of 17.3 % was found in diarrhoea patients mostly, females and almost all of them 20-50 years old. There were no amoebic antibody sero-positives in patients with high CD4+ cell counts. There was no significant association between the detection of anti-E. histolytica antibodies in diarrhoea and non-diarrhoea HN/AIDS patients, considering theirCD4+ cell counts.(p=0.258). Conclusion: Amoebiasis could not be confirmed as an opportunistic infection in HIV/AIDS patients using amoebic antibody seroprevalence.