Browsing by Author "Essien-Baidoo, S."
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Item Electrochemical evaluation of ion substituted-hydroxyapatite on HeLa cells plasma membrane potential(Cogent Engineering, 2019-04-30) Asimeng, B.O.; Tiburu, E.K.; Kaufmann, E.E.; Paemka, L.; Hayford, C.F.; Essien-Baidoo, S.; Dzikunu, O.K.; Anani, P.A.This study reports the electrochemical activities of a novel ion substituted-Hydroxyapatite (HAp) material in contact with HeLa cells. The work was performed to evaluate the inhibitory effects of various concentrations of HAp on ion transfer mechanisms in HeLa cells. The materials (n = 2: HAp1 and HAp3) were prepared at different stirring times from Achatina achatina snail shells and phosphate-containing solution. The structure of the materials and the trace elements concentration were evaluated using x-ray diffractometry and infrared spectrometry as well as atomic absorption spectroscopy. Electrochemical studies conducted on the cells after 30 min of exposure to the materials demonstrated different responses as elucidated by cyclic voltammetry. The voltammograms revealed HAp1 to be non-redox whereas HAp3 was redox active. Minimal concentrations of HAp1 showed high anodic peak current when compared to the HeLa cells alone, indicating a hyperpolarization of the cells. The peak current gradually reduced as the concentration of HAp1 was increased, and then followed by a sudden rise suggesting inhibition of the cell action potential. HAp3 showed a wavy pattern of the anodic peak current when the material concentration was varied. Peak currents of 0.92±0.03 nA and 0.57±0.01 nA were recorded for HAp1 and HAp3, respectively at the highest concentration of 5 µL. The results suggest that different inhibitory mechanisms are at play on the voltage-gated ion channels of the cells, indicating the possibility of using the materials to achieve different cancer proliferation inhibition.Item Molecular diagnosis of Schistosoma infections in urine samples of school children in Ghana(American Journal of Tropical Medicine and Hygiene, 2013-06) Aryeetey, Y.A.; Essien-Baidoo, S.; Larbi, I.A.; Ahmed, K.; Amoah, A.S.; Obeng, B.B.; Van Lieshout, L.; Yazdanbakhsh, M.; Boakye, D.A.; Verweij, J.J.Recent studies using an internal transcribed spacer (ITS)-based real-time polymerase chain reaction (PCR) for the detection of Schistosoma DNA in urine samples has shown high sensitivity and specificity when performed on controls and known microscopy-positive samples. In this study, using 730 urine samples collected from children in five primary schools from different communities in the Greater Accra region of Ghana, specific detection of Schistosoma DNA showed excellent sensitivity of 100% and 85.2% in urines with > 50 eggs/10 mL urine and ≤ 50 eggs/10 mL of urine, respectively. Additionally, Schistosoma-specific DNA was amplified in 102 of 673 samples in which Schistosoma eggs could not be detected with microscopy. Taking microscopy and/or PCR-positive samples as true positives, the negative predictive value calculated was 94.6-100% for each school sampled as compared with 54.3-95.7% using microscopy. This ITS-based real-time PCR proves to be a powerful tool in epidemiological surveys of schistosomiasis providing more precise and sensitive results than microscopy. Copyright © 2013 by The American Society of Tropical Medicine and Hygiene.