Optimization of a Multiresidue Analysis of 65 Pesticides in Surface Water Using Solid-Phase Extraction by LC-MS/MS

An analytical method was developed and validated for simultaneous quantitation of 65 pesticides, including one single solid-phase extraction (SPE) procedure in surface water by liquid chromatography coupled to tandem mass spectroscopy. Different parameters that have an influence on extraction efficiency were evaluated in this research. Different types of cartridges, elution solvents, and sorbent drying time were investigated, and the most appropriate one was selected. Moreover, various pretreatment techniques were applied to remove sediments from water without the loss of pesticides. Centrifugation was introduced as the best option at the beginning of sample preparation to resolve the clogging of the sorbent cartridges. The recoveries of all pesticides ranged from 70% to 120%, with a relative standard deviation of less than 13.7%. The feasibility of the method was evaluated on 10 surface water samples with different concentrations of sand, sediment, and particles.

Application of a composite measure of product adherence, protocol compliance, and semen exposure to a phase III microbicide HIV prevention trial

Background Strict adherence to antiretroviral-based microbicide use is important for effective HIV prevention. We previously developed a composite measure of product adherence, protocol compliance, and semen exposure for determining vaginal use of tenofovir (TFV) 1% gel applicators through biomarkers and residual drug analyses. In this study, we tested the ability of the composite measure in vaginally used TFV gel applicators from a Phase III HIV prevention clinical trial. Methods Used vaginal gel applicators from the FACTS 001 study were swabbed for detection of vaginal bacterial markers (vaginal insertion), semen DNA markers (semen exposure), and residual TFV gel (product use). Results Of 1,098 evaluable TFV and placebo applicators, 80% had detectable vaginal insertion biomarkers and 52% had semen biomarkers. Ninety-nine percent of vaginally inserted applicators TFV applicators had detectable residual TFV as measured by liquid chromatography with tandem mass spectroscopy (LC–MS/MS). Residual TFV levels were also successfully detected using Fourier Transform Infrared (FTIR)-based spectroscopy. Conclusions Vaginal insertion and semen exposure biomarkers were detectable on used TFV 1% gel applicators. Residual TFV on these gel applicators was detectable by LC–MS/MS and FTIR-based spectroscopy, which has potential to be a more convenient and quicker method for detecting drug use. With continual improvements, this composite measure of product adherence, protocol compliance, and semen exposure has potential to assess use of not only TFV gel but also other topical microbicides or products.

Intratumour heterogeneity in microRNAs expression regulates glioblastoma metabolism

While specific microRNA (miRNA) signatures have been identified in glioblastoma (GBM), the intratumour heterogeneity in miRNA expression has not yet been characterised. In this study, we reveal significant alterations in miRNA expression across three GBM tumour regions: the core, rim, and invasive margin. Our miRNA profiling analysis showed that miR-330-5p and miR-215-5p were upregulated in the invasive margin relative to the core and the rim regions, while miR-619-5p, miR-4440 and miR-4793-3p were downregulated. Functional analysis of newly identified miRNAs suggests their involvement in regulating lipid metabolic pathways. Subsequent liquid chromatography–mass spectrometry (LC–MS) and tandem mass spectroscopy (LC–MS/MS) profiling of the intracellular metabolome and the lipidome of GBM cells with dysregulated miRNA expression confirmed the alteration in the metabolite levels associated with lipid metabolism. The identification of regional miRNA expression signatures may underlie the metabolic heterogeneity within the GBM tumour and understanding this relationship may open new avenues for the GBM treatment.

Insight into the Metabolic Profiles of Pb(II) Removing Microorganisms

The objective of the study was to gather insight into the metabolism of lead-removing microorganisms, coupled with Pb(II) removal, biomass viability and nitrate concentrations for Pb(II) bioremoval using an industrially obtained microbial consortium. The consortium used for study has proven to be highly effective at removing aqueous Pb(II) from solution. Anaerobic batch experiments were conducted with Luria-Bertani broth as rich growth medium over a period of 33 h, comparing a lower concentration of Pb(II) with a higher concentration at two different nutrient concentrations. Metabolite profiling and quantification were conducted with the aid of both liquid chromatography coupled with tandem mass spectroscopy (UPLC-HDMS) in a “non-targeted” fashion and high-performance liquid chromatography (HPLC) in a “targeted” fashion. Four main compounds were identified, and a metabolic study was conducted on each to establish their possible significance for Pb(II) bioremoval. The study investigates the first metabolic profile to date for Pb(II) bioremoval, which in turn can result in a clarified understanding for development on an industrial and microbial level.