Comparison of the sensitivity and specificity of six immunoassays for the detection of amphetamines in urine

We analyzed 225 urine samples with FPIA (Abbott Amphetamine/Methamphetamine II on ADx and AxSYM), EMIT (Emit II Plus Monoclonal Amphetamine/Metamphetamine assay and EMIT II Plus Amphetamines assay, EMIT N), and KIMS (standard protocol and MDMA protocol, KIMS and KIMS X, respectively) immunoassays and compared their sensitivity and specificity. All assays were calibrated and used semi-quantitatively. All samples that screened positive by any amphetamine screening method and 15% of the negative samples were confirmed by liquid chromatography-tandem mass spectrometry (LC-MS-MS). A sample was considered positive for amphetamines if amphetamine, methamphetamine, methylenedioxymethamphetamine, methylenedio-xyethylamphetamine, or methylenedioxyamphetamine was present at 250 ng/mL. Ninety (40%) of the samples were positive by LC-MS-MS. The areas under the receiver operating characteristic curve varied between 0.972 (KIMS X) and 1.000 (ADx). The optimal cut-off concentrations varied between 271 ng/mL (EMIT N) and 723 ng/mL (AxSYM). The sensitivity was 100% for ADx and between 93 and 95% for the other assays. The specificity varied between 88% (KIMS) and 100% (EMIT N). Use of a 500 ng/mL screening cut-off would have resulted in identical or very similar results for ADx and KIMS X and large increases in the false positives for AxSYM and EMIT and the false negatives for EMIT N and KIMS.     

VPAC receptors: structure, molecular pharmacology and interaction with accessory proteins

The vasoactive intestinal peptide (VIP) is a neuropeptide with wide distribution in both central and peripheral nervous systems, where it plays important regulatory role in many physiological processes. VIP displays a large biological functions including regulation of exocrine secretions, hormone release, fetal development, immune responses, etc. VIP appears to exert beneficial effect in neuro-degenerative and inflammatory diseases. The mechanism of action of VIP implicates two subtypes of receptors (VPAC1 and VPAC2), which are members of class B receptors belonging to the super-family of GPCR. This article reviews the current knowledge regarding the structure and molecular pharmacology of VPAC receptors. The structure-function relationship of VPAC1 receptor has been extensively studied, allowing to understand the molecular basis for receptor affinity, specificity, desensitization and coupling to adenylyl cyclase. Those studies have clearly demonstrated the crucial role of the N-terminal ectodomain (N-ted) of VPAC1 receptor in VIP recognition. By using different approaches including directed mutagenesis, photoaffinity labelling, NMR, molecular modelling and molecular dynamic simulation, it has been shown that the VIP molecule interacts with the N-ted of VPAC1 receptor, which is itself structured as a 'Sushi' domain. VPAC1 receptor also interacts with a few accessory proteins that play a role in cell signalling of receptors. Recent advances in the structural characterization of VPAC receptor and more generally of class B GPCRs will lead to the design of new molecules, which could have considerable interest for the treatment of inflammatory and neuro-degenerative diseases.     

Short-term uptake of microcystin-LR by Coregonus lavaretus: GST activity and genotoxicity

In the present study, juvenile whitefish weighing 2?g were exposed by force-feeding to two ecologically relevant doses (0.05 and 0.5?μg per fish) of microcystin-LR (MC-LR). Then over 96?h the MC uptake in fish liver and muscle was measured, as the activity of the detoxification enzyme glutathione S-transferase (GST) in the liver, and the genotoxicity impact on red blood cells. Results show that (1) the MC-LR equivalent concentrations increased for both doses and in both organs of whitefish with approximately threefold lower concentrations for the low dose compared to the high dose in both organs and threefold lower concentrations in the muscle compared to the liver for each dose (2) the liver GST activity increased during the first 48?h of exposure with fivefold higher GST activity for the highest dose at 48?h compared to control and (3) MC-LR leads to deoxyribonucleic acid strand breaks that were detected by the comet assay and shown to be partially repaired. This work demonstrates that European whitefish could be impacted by cyanobacteria toxins due to rapid microcystin uptake, especially in the context of chronic contamination, which can occur during long bloom episodes.     

Juvenile roach (<Emphasis Type="Italic">Rutilus rutilus</Emphasis>) increase their anaerobic metabolism in response to copper exposure in laboratory conditions

This study aims to determine the potential impairment of cell energy synthesis processes (glycolysis and respiratory chain pathways) by copper in juvenile roach at different regulation levels by using a multi-marker approach. Juvenile roach were exposed to 0, 10, 50, and 100 µg/L of copper for 7 days in laboratory conditions. The glycolysis pathway was assessed by measuring the relative expression levels of 4 genes encoding glycolysis enzymes. The respiratory chain was studied by assessing the electron transport system and cytochrome c oxidase gene expression. Muscle mitochondria ultrastructure was studied, and antioxidant responses were measured. Furthermore, the main energy reserves—carbohydrates, lipids, and proteins—were measured, and cellular energy was evaluated by measuring ATP, ADP, AMP and IMP concentrations. This study revealed a disturbance of the cell energy metabolism due to copper exposure, with a significant decrease in adenylate energy charge in roach exposed to 10 μg/L of copper after 1 day. Moreover, ATP concentrations significantly decreased in roach exposed to 10 μg/L of copper after 1 day. This significant decrease persisted in roach exposed to 50 µg/L of copper after 7 days. AMP concentrations increased in all contaminated fish after 1 day of exposure. In parallel, the relative expression of 3 genes encoding for glycolysis enzymes increased in all contaminated fish after 1 day of copper exposure. Focusing on the respiratory chain, cytochrome c oxidase gene expression also increased in all contaminated fish at the two time-points. The activity of the electron transport system was not disturbed by copper, except in roach exposed to 100 µg/L of copper after 1 day. Copper induced a metabolic stress. Juvenile roach seemed to respond to the ensuing high energy demand by increasing their anaerobic metabolism, but the energy produced by the anaerobic metabolism is unable to compensate for the stress induced by copper after 7 days. This multi-marker approach allows us to reach a greater understanding of the effects of copper on the physiological responses of juvenile roach.     

Predictors for establishing recommended phase 2 doses: analysis of 320 dose-seeking oncology phase 1 trials

Introduction For decades, determination of the recommended Phase 2 dose (RP2D) was based on the toxicity (especially the maximum tolerated dose or MTD) experienced by patients enrolled in dose-escalating Phase 1 trials investigating anti-cancer agents. Recent studies suggest that this toxicity-based strategy is not suitable for modern anti-cancer agents. We conducted a retrospective study to identify the risk factor(s) for failing to determine the RP2D according to the MTD. Material and methods We analyzed 320 recently published (1997–2008) Phase 1 trials using the maximum tolerated dose (MTD) to define the P2RD. We analyzed the current definitions of RP2D and then identified the risk factors for not establishing the RP2D using the odds ratio and 95% confidence intervals. Interactions between these risk factors were explored using the logistic regression model and CHAID algorithm. Results 18% of contemporary dose-seeking Phase 1 trials did not identify a RP2D. The logistic regression analysis showed that the risk factors for not identifying the RP2D were: investigation of molecular targeted therapies (RR = 3.0, p = 0.0017), lack of justification of the starting dose (RR = 5.9, p = 0.0121) and lack of definition of the MTD (RR = 8.4, p = 0.0006). The CHAID algorithm confirmed the importance of the methodological parameters. Discussion This study confirms the difficulty of determining the RP2D of molecular targeted therapy using conventional methods. However, it underlines the major importance of two methodological points: definition of the MTD and justification of the starting dose.     

Disulfide prodrugs of albitiazolium (T3/SAR97276): synthesis and biological activities

We report herein the design, synthesis, and biological screening of a series of 15 disulfide prodrugs as precursors of albitiazolium bromide (T3/SAR97276, compound 1), a choline analogue which is currently being evaluated in clinical trials (phase II) for severe malaria. The corresponding prodrugs are expected to revert back to the active bis-thiazolium salt through an enzymatic reduction of the disulfide bond. To enhance aqueous solubility of these prodrugs, an amino acid residue (valine or lysine) or a phosphate group was introduced on the thiazolium side chain. Most of the novel derivatives exhibited potent in vitro antimalarial activity against P. falciparum. After oral administration, the cyclic disulfide prodrug 8 showed the best improvement of oral efficacy in comparison to the parent drug.     

Add-on Treatment of Quetiapine for Fibromyalgia: A Pilot, Randomized, Double-Blind, Placebo-Controlled 12-Week Trial

ABSTRACT: Recently, second-generation antipsychotic drugs have attracted interest in the treatment of chronic pain, including fibromyalgia (FM). Preliminary uncontrolled studies have shown that quetiapine treatment may be helpful for FM patients. In this trial, we sought to examine-for the first time-the efficacy and tolerability of quetiapine as a treatment for FM and its associated psychiatric symptoms. This was a 12-week double-blind, randomized, placebo-controlled trial of quetiapine XR as an add-on treatment for FM syndrome. Fifty-one female FM patients were randomized, and a flexible dosage of 50 to 300 mg/d was used. The primary outcome was the change from baseline to end point in the Fibromyalgia Impact Questionnaire total score. Secondary outcomes included mood symptoms, sleep disturbances, and tender points. Using a low dose (mean = 132.2 mg) of quetiapine, we observed significant benefits of drug treatment on sleep, uncertain effects on FM and mood symptoms, but no effects on pain, in a small group of polymedicated FM patients. Quetiapine was generally well tolerated.