[³H]hypoxanthine incorporation in P falciparum cultures sustained with RBCs in different hydration states. Following parasite invasion in cultures sustained with RBCs of different volumes, parasites were ring-stage synchronized and incubated with [³H]hypoxanthine for 24 hours. After this period, parasite growth was assessed by measuring [³H]hypoxanthine incorporation, as described in “Materials and methods.” The columns and error bars report the means and SDs of quadruplicate measurements expressed as a percent of the incorporation in untreated controls (right column).