The protozoan parasite responsible for malaria affects over 500 million people each year. Current antimalarials have experienced decreased efficacy due to the development of drug-resistant strains of Plasmodium spp., resulting in a critical need for the discovery of new antimalarials. Hemozoin, a crystalline by-product of heme detoxification that is necessary for parasite survival, serves as an important drug target. The quinoline antimalarials, including amodiaquine and chloroquine, act by inhibiting the formation of hemozoin. The formation of this crystal does not occur spontaneously, and recent evidence suggests crystallization occurs in the presence of neutral lipid particles located in the acidic digestive vacuole of the parasite. To mimic these conditions, the lipophilic detergent NP-40 has previously been shown to successfully mediate the formation of ␤-hematin, synthetic hemozoin. Here, an NP-40 detergent-based assay was successfully adapted for use as a high-throughput screen to identify inhibitors of ␤-hematin formation. The resulting assay exhibited a favorable Z of 0.82 and maximal drift of less than 4%. The assay was used in a pilot screen of 38,400 diverse compounds at a screening concentration of 19.3 M, resulting in the identification of 161 previously unreported ␤-hematin inhibitors. Of these, 48 also exhibited >90% inhibition of parasitemia in a Plasmodium falciparum whole-cell assay at a screening concentration of 23 M. Eight of these compounds were identified to have nanomolar 50% inhibitory concentration values near that of chloroquine in this assay.

Supplemental melatonin has been used to treat sleep onset insomnia in children with autism spectrum disorders (ASD), although the mechanism of action is uncertain. We assessed endogenous and supplemental melatonin profiles in relation to sleep in nine children with ASD. In endogenous samples, maximal melatonin concentration (Cmax) and time to peak concentration (Tmax) were comparable to those previously published in the literature for typically developing children, and dim light melatonin onsets were captured in the majority of children. In treatment samples (supplemental melatonin), melatonin parameters were also comparable to those previously published for typically developing children. Our findings support that children with ASD and insomnia responsive to low dose melatonin treatment have relatively normal profiles of endogenous and supplemental melatonin.

Organophosphorus nerve agent (OPNA) adducts to butyrylcholinesterase (BChE) can be used to confirm exposure in humans. A highly accurate method to detect G-series and V-series OPNA adducts to BChE in 75 μL of filtered blood, serum, or plasma has been developed using immunomagnetic separation (IMS) coupled with liquid chromatography tandem mass spectrometry (LC-MS/MS). The reported IMS method captures > 88% of the BChE in a specimen and corrects for matrix effects on peptide calibrators. The optimized method has been used to quantify baseline BChE levels (unadducted and OPNA-adducted) in a matched set of serum, plasma and whole blood (later processed in-house for plasma content) from 192 unexposed individuals to determine the interchangeability of the tested matrices. The results of these measurements demonstrate the ability to accurately measure BChE regardless of the format of the blood specimen received. Criteria for accepting or denying specimens were established through a series of sample stability and processing experiments. The results of these efforts are an optimized and rugged method that is transferrable to other laboratories and an increased understanding of the BChE biomarker in matrix.

US Centers for Disease Control and Prevention.