Browsing by Author "Udagama-Randeniya, P.V."

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A Double antibody sandwich ELISA for the diagnosis of vivax malaria: a tool for further research
(University of Colombo, 2000) Seneviratna, G.D.C.N.; Manamperi, A.A.P.S.; Kapilananda, G.M.G.; Longacre, S.; Handunnetti, S.M.; Udagama-Randeniya, P.V.
A diagnostic assay for Plasmodium vivax based on a double antibody sandwich enzyme-linked immunosorbent assay (DAS ELISA) was established to detect the merozoite surface protein 1 (PvMSP1) in wild isolates. This assay was based on the recombinant protein p19, a C-terminal processing product of PvMSP1. Of the two anti-P. vivax monoclonal antibodies (MAbs) selected, A21 was used as the capture antibody while horse radish peroxidase labelled A8 served as the probing second antibody. Optimized conditions established for p19 based DAS ELISA with the exception of a lower concentration of Tween-20 in buffers were suitable to screen lysed whole blood of malaria patients. This assay had a specificity of 100 percent for P. vivax and all the isolates of P. falciparum tested negative. Of the P. vivax-infected blood samples, only those containing both compact and schizont stages were diagnosed positive. The rest of the isolates tested negative either due to stage specificity of this assay or to the antigenic diversity of PvMSP1 in wild isolates. This test demonstrated a sensitivity of 27.58 percent and an accuracy of 63.15 percent. The positive and negative predicted values of this ELISA were 100 percent and 57.14 percent, respectively. Therefore, the P. vivax specific DAS ELISA developed and tested in the present study is not sufficiently sensitive to be used as a diagnostic tool for vivax malaria. Nevertheless, a baseline was established for development of diagnostic ELISA for future use with a more appropriate antigen.
Haematological parameters of three species of wild caught microchiropteran bats, Miniopterus schreibersii, Taphozous melanopogon and Hipposideros lankadiva in Sri Lanka
(Journal of Science of the University of Kelaniya Sri Lanka, 2005) Ratnasooriya, W.D.; Udagama-Randeniya, P.V.; Yapa, W.B.; Digana, P.M.C.B.; Dharmasiri, M.G.
This study,for the first time in South Asia, examines haematological parameters of thre species of wild caught Sri Lankan microchiropteran bats, belonging to three different families having different global zoogeographical distributions; Miniopterus schreibersii (Vespertilionidae: n=12), Taphozous melanopogon (Emballonuridae; n=19) and Hipposideros lankadiva (Hipposiderosidae; n=15). Blood samples were obtained from the median vein and the total white blood cell (WBC) count, red blood cell (RBC) count, packed cell volume (PCV), haemoglobin content(Hb), mean corpuscular volume (MCV) and mean corpuscular haemoglobin content (MCHC) were determined using standard haematological techniques. lnterspecies differences existed in some of the parameters monitored, i.e. PCV, MCV, WBC and RBC counts. % of neutrophils and lymphocytes. On the other hand, a gender discrepancy was recorded for T.melanopgon with respect to neutrophils and lymphocytes, and for M. schreibersii with respect to the total WBC count. The highest WBC count and the lowest PCV and MCV were found in M. schreibersii. T.melanopgon registered the highest percentage of lymphocytes and the lowest percentage of neutrophils, while H. lankadiva possessed the highest MCV. Haematological values were recorded also for a single lactating T.melanopogon.