The in vitro effect of the following antimicrobial agents on Toxoplasma gondii tachyzoites were studied: artemisinin ether (arteether), cycloguanil hydrochloride (cycloguanil), mefloquine, primaquine phosphate, and quinine sulfate, as well as the calcium channel blocker verapamil and the calmodulin inhibitor trifluoperazine hydrochloride. Arteether at > or = 0.5 micrograms/ml and cycloguanil at > or = 1.0 micrograms/ml inhibited T. gondii in vitro. Cycloguanil (2.5 micrograms/ml) combined with a noninhibitory concentration of sulfadiazine (25 micrograms/ml) inhibited T.
Improvements are made to our gas-chromatography-mass-spectrometry-based assay for quantifying low levels of DNA-uracil. Folate deficiency leads to increased deoxyuridine monophosphate/thymidylate (dUMP/dTMP) ratios and uracil misincorporation into DNA, which may increase cancer risk. Vitamin B6 (B6) deficiency might also result in increased DNA-uracil because B6 is a cofactor for serine hydroxymethyltransferase, which catalyzes the methylation of tetrahydrofolate (THF) to methylene-THF, the folate form that is required to convert dUMP to dTMP.