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Fig. 1 | BMC Medicine

Fig. 1

From: Plasmodium falciparum dihydroartemisinin-piperaquine failures in Cambodia are associated with mutant K13 parasites presenting high survival rates in novel piperaquine in vitro assays: retrospective and prospective investigations

Fig. 1

In vitro and ex vivo piperaquine survival assays (PSA). Top: synchronization and timing of 200 nM piperaquine exposure for in vitro PSA performed on culture-adapted P. falciparum isolates collected on day 0 from patients subsequently followed-up and presenting or not a late recrudescence. Bottom: timing of 200 nM piperaquine exposure for the ex vivo PSA performed on circulating parasites obtained directly from the blood of patients with falciparum uncomplicated malaria. The ex vivo PSA was performed only on isolates with parasite densities ≥0.1 %. The survival rates were interpretable when the parasite growth rates (parasite density at 72 h/parasite density at 0 h) were >1.5 for the in vitro PSA and >1 for the ex vivo PSA. Dark blue rectangles show culture medium containing 200 nM piperaquine (exposed culture) or 0.5 % lactic acid (non-exposed culture). Light blue rectangles represent complete culture medium without drugs (exposed and non-exposed cultures). PPQ, Piperaquine; PSA, Piperaquine survival assay

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