S Asiri

University of Nigeria, Nsukka, Enugu State, Nigeria

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Publications (5)11.31 Total impact

  • P O Ogbunude, S A Asiri
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    ABSTRACT: Treatment with the drugs berenil, dibromopropamidine, pentamidine and CGP-4O-215 were found to alter levels of intracellular polyamines of Acanthamoeba polyphagia trophozoites in organisms. While the polyamine, spermidine, consistently remained higher in the control organisms incubated at 8, 16 and 32 h respectively, the level fluctuated significantly from below 5% to 40% in drug-treated organisms. A novel polyamine (polyamine F), yet to be identified, representing 80% of the total polyamine extracts and seen in control organisms after 48 h of incubation (stationary phase), was seen much earlier in the drug treated organisms. Pentamidine, dibromopropamidine and CGP-4O-215 induced the appearance of the novel polyamine in the trophozoites after only 8 h of incubation with the drugs while induction by berenil occurred after 32 h. It is suggested that diamidine drugs either induce encystment or alter the pathway of polyamine metabolism in Acanthamoeba. If inducing encystment is the main mode of reaction, then drugs that induce early encystment will be less effective in treatment than those that delay it.
    Drugs under experimental and clinical research 02/2001; 27(4):127-33.
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    ABSTRACT: A technique based on binding of eosin dye to cell was applied to quantitate Acanthamoeba trophozoites in culture. Using this technique in combination with the uptake of radiolabelled adenosine, we assessed the activities of triazole (saperconazole), imidazole (ketoconazole, miconazole) and diamidine (berenil, pentamidine, dibromopropamidine) compounds against A. polyphaga trophozoites. The quantity of dye bound to the trophozoites correlated (r = 0.99) with the number of organisms per well. When inhibition of the growth of Acanthamoeba was the only parameter used to measure the effectiveness of these drugs, saperconazole was found to be most active with IC50 (concentration of drug that inhibited by 50%, the growth of A. polyphaga trophozoites incubated at 28 degrees C for 48 h) of 0.95 microM. The IC50s of the other drugs ranged from > or = 1500 microM for micronazole, the least active, to 3.0 microM for berenil. However, when efficacy was assessed by combining inhibition of growth with the uptake of [14C-8]adenosine by the drug treated organism, the diamidines, particularly berenil and pentamidine were considered most potent.
    International Journal for Parasitology 11/1994; 24(7):975-80. · 3.64 Impact Factor
  • Advances in experimental medicine and biology 02/1994; 370:503-8. · 1.83 Impact Factor
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    ABSTRACT: Trophozoites of two Acanthamoeba polyphaga strains (RYD and 435) were readily detached from plastic culture flasks or multiwell plates by 5 min exposure to a detaching fluid containing 0.005% of Triton X-100 and 0.05% ammonium sulphate. This treatment also led to rounding of cells and thus permitted convenient and reproducible counting by either hemocytometer or electronic particle counter. The detaching fluid did not impair viability even after exposure up to 1 h.
    Tropical medicine and parasitology: official organ of Deutsche Tropenmedizinische Gesellschaft and of Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) 01/1992; 42(4):415-6.
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    ABSTRACT: BALB/c mice inoculated nasally with Acanthamoeba culbertsoni, resulting in amebic encephalitis and death 3-7 days, were treated with rifampicin prophylactically (daily for 2 days with 75 and 100 mg/kg) and after infection (daily for 5 days with doses of 10-100 mg/kg). Prophylactic treatment resulted in full protection against infection, as assessed by absence of symptoms of central nervous system malfunction and negative brain culture 10 days after inoculation. Curative treatment was effective at the same doses; however, at doses of 10, 25, and 50 mg/kg, only two of six animals were free of symptoms and infection.
    The Journal of Infectious Diseases 05/1991; 163(4):916-7. · 5.85 Impact Factor

Publication Stats

12 Citations
11.31 Total Impact Points

Institutions

  • 2001
    • University of Nigeria
      • Department of Medical Biochemistry
      Nsukka, Enugu State, Nigeria
  • 1992–1994
    • King Faisal Specialist Hospital and Research Centre
      • Department of Biological and Medical Research
      Jeddah, Mintaqat Makkah, Saudi Arabia