Publication: Plasmodium vivax: Isotopic, PicoGreen, and microscopic assays for measuring chloroquine sensitivity in fresh and cryopreserved isolates
Issued Date
2006-09-01
Resource Type
ISSN
10902449
00144894
00144894
Other identifier(s)
2-s2.0-33746874044
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Mahidol University
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SCOPUS
Bibliographic Citation
Experimental Parasitology. Vol.114, No.1 (2006), 34-39
Suggested Citation
Varakorn Kosaisavee, Rossarin Suwanarusk, François Nosten, Dennis E. Kyle, Marion Barrends, James Jones, Ric Price, Bruce Russell, Usa Lek-Uthai Plasmodium vivax: Isotopic, PicoGreen, and microscopic assays for measuring chloroquine sensitivity in fresh and cryopreserved isolates. Experimental Parasitology. Vol.114, No.1 (2006), 34-39. doi:10.1016/j.exppara.2006.02.006 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/23309
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Title
Plasmodium vivax: Isotopic, PicoGreen, and microscopic assays for measuring chloroquine sensitivity in fresh and cryopreserved isolates
Abstract
In vitro susceptibility tests provide information on the intrinsic response of Plasmodium vivax to antimalarials, free from confounding factors such as host immunity or relapse. This study examined the utility of radioisotope and PicoGreen assays as alternatives to the traditional microscopic examination for assessing response of P. vivax to antimalarial drugs. There was no significant difference in the mean chloroquine IC50of P. vivax (n = 40) as determined by the microscopic (33.4 ng/ml), isotopic (33.6 ng/ml), and PicoGreen (39.1 ng/ml) assays, respectively (F = 0.239, df = 2, 51, and p = 0.788). However measurement of IC50s by the microscopic method was slightly more successful in producing valid assays (57%), compared to the isotopic (32.5%) and PicoGreen (45.5%) methods. In a paired comparison of 20 fresh and cryopreserved isolates as examined by the microscopic method, there were no significant differences between the mean IC50responses (T = 1.58, df = 15, and p = 0.34). Detailed methodologies for the short time culture of field and cryopreserved P. vivax are described. Although the microscopic in vitro assay provides a useful method for characterizing the drug susceptibility phenotype of P. vivax isolates, its utility is limited by a laborious methodology and need for highly skilled microscopists. Future efforts should focus on further development of high throughput assays such as the PicoGreen assay as described in this study. © 2006 Elsevier Inc. All rights reserved.