Browsing by Author "Yeboah, P.O."
Now showing 1 - 7 of 7
Results Per Page
Sort Options
Item Determination of levels of polychlorinated biphenyl in transformers oil from some selected transformers in parts of the Greater Accra Region of Ghana(Chemosphere, 2010-11) Buah-Kwofie, A.; Yeboah, P.O.; Pwamang, J.Although polychlorinated biphenyls have never been manufactured in Ghana, it has been used extensively as dielectric fluid in electric transformers and capacitors. However, very little is known of its health and environmental impacts by both managers of these transformers and capacitors and also the general public. This work therefore seeks to explore INAA as a possible alternative to screening transformer oils for PCBs by determining the total chlorine content. The total chlorine content of transformer oil samples from Ghana that tested positive and some randomly selected samples that tested negative from screening using CLOR-N-OIL test kits, have had their total chlorine estimated. INAA using the Research Reactor located at the Ghana Atomic Energy Commission was used to estimate the total chlorine content of the oil samples. Neutron Activation and gamma ray spectroscopy using HPGe detector coupled to MAESTRO 32 software was used to determine the total chlorine content by integrating the peak area of the spectrum into a simplified program that was developed from the activation equation. Instrumental Neutron Activation Analysis was able to validate the result obtained from the test kits screening with accuracy 7.5%.The minimum total chlorine content of the positive samples determined by NAA was 71.34μgg-1. © 2010 Elsevier Ltd.Item In Vitro Studies on the Effect of Chloroquine Phosphate on the Metabolism of the Rat Red Blood Cells(University of Ghana, 1972-11) Yeboah, P.O.; Asante, G.S.; Larway, P.F.; Lovelace, C.A.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Biochemistry, Cell and Molecular BiologyEvidence is presented to show that in vitro. (1) High levels of chloroquine phosphate can induce hemolysis in the rat red blood cells; and (2) chloroquine-induced hemolysis is characterised by a fall in GSH levels, unless glucose is present in very high concentrations* Chloroquine phosphate is a member of the 4-aminoquinoline series of drugs used for treating acute malaria due to infection fctj Plasmodium vivdx« Plasmodium falciparum. Plasmodium malariae and Plasmodium ovale. In vitro studies were made on red blood cells incubated with chloroquine phosphate to investigate a possible chloroquine-induced hemolysis in rat red blood cells. A wide range of chloroquine phosphate concentrations were tested. After 4 hours incubation of the mixture at 3?°C; 6,3 1 10~% caused only - 2. hemolysis in the rat red blood cells; whereas 2.5 x 10 !-i chloroquine caused 66,5a hemolysis. Complete hemolysis was however observed when 4.2 x 10 chloroquine phosphate was used in the incubation system. -1 -2 Either 3.78 x 10 M glucose or 2,0 x 10 M ATP protected the red _2 blood cells from hemolysis induced by 2.5 x 10 M chloroquine phosphate. Hemolysis induced by chloroquine phosphate was found to be characterised by (a) a fall in GSH level, and (b) an increase in the osmotic fragility of the rat red blood cells. These characteristics are similar to primaquine- induced hemolysis in -.red blood cells. The possibility is discussed that based upon osmotic fragility studies, the site of hemolytic action of chloroquine phosphate could be directly on the red cell membrane where the drug might interfere with sulfhydryl groups.Item Levels and seasonal variations of organochlorine pesticides in urban and rural background air of southern Ghana(Environmental Science and Pollution Research, 2012-06) Adu-Kumi, S.; Kareš, R.; Literák, J.; Borůvková, J.; Yeboah, P.O.; Carboo, D.; Akoto, O.; Darko, G.; Osae, S.; Klánová, J.Urban, suburban and rural background air samples were collected in southern Ghana in 2008 employing polyurethane foam disc passive air samplers (PAS). PAS were analysed for organochlorine pesticides (OCPs), namely hexachlorocyclohexanes (α-, β-, γ- and δ-hexachlorocyclohexane), dichlorodiphenyltrichloroethane including metabolites (o,p′- and p,p′-DDT, DDE and DDD), hexachlorobenzene, pentachlorobenzene, aldrin, dieldrin, endrins (endrin, endrin aldehyde and endrin ketone), isodrin, heptachlors (heptachlor, heptachlor epoxide A and heptachlor epoxide B), chlordanes (α-, β-chlordane, oxychlordane and trans-nonachlor), endosulfans (α- and β-endosulfan and endosulfan sulphate), methoxychlor and mirex using a gas chromatograph coupled to a mass spectrometer. The levels of OCPs ranged for the individual pesticides from below limit of quantification to 750 pg m-3 (for α-endosulfan), and current agricultural application seemed to be the main primary source of most abundant pesticides. Re-volatilization of previously used pesticides from contaminated soils could not be ruled out either as potential secondary source of contamination, especially in warm and dry seasons and periods of intensive agricultural activities. Higher atmospheric concentrations were observed in November and December during the dry season compared to lower concentrations observed in June, July and August when the country experiences heavy rains. The highest seasonal variation was observed for currently used pesticides as α-endosulfan. A p,p′-DDT/p,p′-DDE ratio suggested recent inputs of fresh technical DDT. © 2012 Springer-Verlag.Item The Metabolism Of Chloroquine Phosphate By Rat Liver Cell Fractions(University of Ghana, 1979-06) Yeboah, P.O.; Asante, G.S.; Toothill,C.; University of Ghana, College of Health Sciences, School of Biomedical and Allied Health Sciences, Department of Medical Biochemistry1. The metabolisn of chloroquine phosphate by the various subcellular fractions of the rat liver honnogenate has been studied. (a) Both the mitochondrial and soluble fractions were found to contain enzyme systems that degraded chloroquine to varying degrees. (b) The maximum activity of chloroquine degradation was however found in the microsomal fraction, 2. In vitro studies on the metabolisij of (ring-3-^C) chloroquine led to the conclusion that the microsomal subcellular fraction was capable of breaking chloroquine down to a minimum of eight metabolites in which the 4-aminoquinoline nucleus remained intact. 3. A number of 4-aminoquinoline derivatives, including the 4'-hydroxy, the 4'-aldehyde, the primary amine (SN 13617) derivatives of chloroquine have been successfully synthesized and characterized, 4. Using the synthesized derivatives of chloroquine as chromatographic standards, four of the eight metabolites of chloroquine (see ' 2 * above) were identified as the primary amine derivative (SN 13617), the 4'-hydroxy and the 4'-aldehyde derivatives and 7 -chloro-4-aminoquinoline. 5. Based on in vitro studies on the metabolism of both chloroquine and the synthesized derivatives by the hepatic microsomal fraction of rat, it has been tentatively suggested that the metabcLlic degradation of chloroquine proceeds by the formation of the following metabolit.££.• in the order: i) The hydroxychloroquine, HCQ (ie. the analogue of chloroquine in which a hydroxyl group has been substituted in the 2-position of N-ethyl groups). ii) The secondary amine derivative (SN 13616); iii) The primary amine derivative (SN 13617); iv) The 4'-aldehyde derivative, which is largely converted into the 4'-hydroxy derivative. 6 . An alternative pathway for the secondary amine derivative ('SN 13616) has also been proposed. Through this pathway, chloroquine may be converted through SN 13616 and an unidentified intermediate V, to a final product 4-amino-7-chloroquinoline. It has also been demonstrated that in presence of SKF 525A, the metabolism of chloroquine is apparently activated through the latter alternative pathway. 7. Evidence is also presented to show that the proposed pathway for chloroquine metabolism might be common to both the rat and man.Item Nutrient chemistry of the Densu River in Ghana(The Environmentalist, 2010-06) Fianko, J.R.; Lowor, S.T.; Donkor, A.; Yeboah, P.O.The impact of anthropogenic activities on the fluctuation of nutrients along the Densu River and its tributaries was studied. High concentrations of nutrients were observed in the study area but the river was found to be circumneutral and fresh with pH ranging between 6.54 and 7.84. The levels of NH4 +-N ranged between 0.21 and 2.1 mg L-1 with mean concentration of 1.19 ± 0.02 mg L-1 while that of nitrate is between 0.13 and 5.21 mg L-1 with a mean concentration of 2.07 ± 0.01 mg L-1. The levels of PO4 3--P fluctuated within the range 0.54 and 1.04 mg L-1 with a mean of 0.84 ± 0.01 mg L-1. The Densu River Basin was also found to be with organic matter with depleted dissolved oxygen. The river recorded high BOD values ranging from 6.91 to 18.8 mg L-1. Concentration of nutrients and organic pollutants increased as a consequence of anthropogenic inputs particularly from domestic, agricultural and municipal sources. The highly impaired sites were those located close to the urbanized, agricultural and high-density residential areas. The relatively high concentration of nitrate and phosphate in the river indicated that it was quite eutrophic. © Springer Science+Business Media, LLC 2010.Item Organochlorine pesticides (OCPs), dioxin-like polychlorinated biphenyls (dl-PCBs), polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo furans (PCDD/Fs) in edible fish from Lake Volta, Lake Bosumtwi and Weija Lake in Ghana(Chemosphere, 2010-10) Adu-Kumi, S.; Kawano, M.; Shiki, Y.; Yeboah, P.O.; Carboo, D.; Pwamang, J.; Morita, M.; Suzuki, N.Organochlorine pesticides (OCPs), dioxin-like polychlorinated biphenyls (dl-PCBs), polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo furans (PCDD/Fs) were measured by a high resolution gas chromatograph-high resolution mass spectrometer (HRGC/HRMS) in selected edible fish from three freshwater bodies, Lake Volta, Lake Bosumtwi and Weija Lake in Ghana. The levels of organochlorine pesticides measured in this study were generally low. The highest concentration of OCPs was measured for dichlorodiphenyltrichloroethane compounds (DDTs) (p,. p′-DDT, o,. p′-DDT, p,. p′-DDE, o,. p′-DDE, p,. p′-DDD and o,. p′-DDD), followed by chlordane compounds (CHLs) (trans-chlordane, cis-chlordane, trans-nonachlor and cis-nonachlor), hexachlorobenzene (HCB) and gamma-hexachlorocyclohexane (γ-HCH). The relatively high ratio of p,. p′-DDT/. p,. p′-DDE in tilapia and catfish with an extremely high value in catfish purchased from a local market at Madina, a suburb of Accra, however, suggests the fresh contamination of technical DDT in Ghana. Although PCDD/Fs and dl-PCBs showed relatively low levels, the concentrations are, however, comparable with recent data of some developed countries. There is a potential health risk from DDTs, PCDD/Fs and dl-PCBs for the general population of Ghana because fish is one of their important protein sources. It is therefore necessary to estimate the total intake of DDTs, PCDD/Fs and dl-PCBs, and to assess the health risks for the general population of Ghana. © 2010 Elsevier Ltd.Item A preliminary assessment of consumer's exposure to organochlorine pesticides in fruits and vegetables and the potential health risk in Accra Metropolis, Ghana(Food Chemistry, 2011-10) Bempah, C.K.; Donkor, A.; Yeboah, P.O.; Dubey, B.; Osei-Fosu, P.Accra Metropolis is the major recipient of agricultural produce in Ghana, with almost the entire population depending on rural agricultural activities for subsistence. To increase agricultural produce, various forms of pesticides are normally used in fruits and vegetable farming. The consequence is that several cases of pesticide poisoning have been observed. In this preliminary study, a field survey was carried out to assess the knowledge, attitudes, and peoples' perception concerning the use of pesticides by farmers in fruit production. The residual concentrations of selected pesticides in pawpaw, imported apples and tomato samples and the potential health risks associated with the exposure to these pesticides were also assessed. The field survey data indicated that more than 70% of the participants reported one or more poisoning upon fruits consumption resulting in pesticide-related illnesses. Pesticide residues in the various environmental samples were determined by gas chromatography with electron capture detector (GC-ECD). The results showed that, the levels of pesticide residues varied from <0.01 μg/g to as high as 0.11 μg/g depending on the pesticide monitored. The analysis of health risk estimates revealed heptachlor, heptachlor epoxide, endrin aldehyde, and endrin ketone levels exceeded the reference dose, suggesting a great potential for systemic toxicity in children considered the most vulnerable population subgroup. Lastly, the public is in the know of pesticide residues in fruits and calls for the curtailing of pesticide use on fruits and vegetable production via educational programmes for farmers on control and safer use of pesticides. © 2011 Elsevier Ltd. All rights reserved.