Untargeted metabolomics reveals the preventive effect of quercetin on nephrotoxicity induced by four organophosphorus pesticide mixtures.

This research aimed to explore the protective effect of quercetin against nephrotoxicity induced by four organophosphate pesticide mixtures (PM) using untargeted metabolomics technology in rat kidneys. Sixty male Wistar rats were randomly divided into six groups: control, low-dose quercetin treated (10 mg/kg bw), high-dose quercetin treated (50 mg/kg bw), PM-treated, and two dosages of quercetin + PM-treated. Metabolomics results showed that 17 differential metabolites were identified in the PM-treated group, and pathway analysis revealed that renal metabolic disorders include purine metabolism, glycerophospholipid metabolism, and vitamin B6 metabolism. When high-dose quercetin and PM-treated were administered to rats concurrently, the intensities of differential metabolites were substantially restored (p < 0.01), suggesting that quercetin can improve renal metabolic disorders caused by organophosphate pesticides (OPs). Mechanistically, quercetin could regulate the purine metabolism disorder and endoplasmic reticulum stress (ERS)-mediated autophagy induced by OPs by inhibiting XOD activity. Moreover, quercetin inhibits PLA2 activity to regulate glycerophospholipid metabolism and it could also exert antioxidant and anti-inflammatory effects to correct vitamin B6 metabolism in rat kidneys. Taken together, the high dose of quercetin (50 mg/kg. bw) has a certain protective effect on OPs-induced nephrotoxicity in rats, which provides a theoretical basis for quercetin against nephrotoxicity caused by OPs.

Desensitization to chemical and food sensitivities by low-dose immunotherapy ascertained by provocation neutralization is associated with reduced influx of calcium ions into lymphocytes.

Background Food and chemical sensitivities have detrimental effects on health and the quality of life. The natural course of such sensitivities can potentially be altered through various types of allergen-specific immunotherapy, including low-dose immunotherapy. The molecular mechanism by which low-dose immunotherapy causes desensitization has not thus far been elucidated. While resting lymphocytes maintain a low cytosolic calcium ion concentration, antigen receptor signaling results in calcium ion influx, predominantly via store-operated calcium channels. We therefore hypothesized that desensitization by low-dose immunotherapy is associated with reduced influx of calcium ions into lymphocytes. The aim of this study was to test this hypothesis. Methods Intracellular lymphocytic calcium ion concentrations were assayed in a total of 47 patients, following incubation with picogram amounts of the test allergens, using a cell-permeable calcium-sensing ratiometric fluorescent dye and fluorescence spectroscopy, both at baseline and following successful provocation neutralization treatment with low-dose immunotherapy. Results Low-dose immunotherapy was associated with a reduction in lymphocytic intracellular calcium ion concentration following treatment of: 23 % for metabisulfite sensitivity (p<0.0004); 12 % for salicylate sensitivity (p<0.01); 23 % for benzoate sensitivity (p<0.01); 30 % for formaldehyde sensitivity (p<0.0001); 16 % for sensitivity to petrol exhaust (p<0.003); 16 % for natural gas sensitivity (p<0.001); 13 % for nickel sensitivity (p<0.05); 30 % for sensitivity to organophosphates (p<0.01); and 24 % for sensitivity to nitrosamines (p<0.05). Conclusions Low-dose immunotherapy may affect baseline levels of intracellular calcium in lymphocytes, supporting the premise that allergens affect cell signaling in immune cells and provocation neutralization immunotherapy helps to promote more normal immune cell signaling.

Effects of therapeutic and supratherapeutic doses of oral tedizolid phosphate on cardiac repolarisation in healthy volunteers: a randomised controlled study.

Drug-induced prolongation of the QT interval on the electrocardiogram (ECG) infrequently results in Torsades de pointes, a potentially fatal arrhythmia. Therefore, thorough QT analysis of new drugs is a regulatory requirement. The objective of this phase 1 study was to assess the effects of oral tedizolid phosphate on the QT interval corrected with Fridericia's formula (QTcF) in healthy adult subjects. A single therapeutic dose (200 mg) and a supratherapeutic dose (1200 mg) of tedizolid phosphate were administered to characterise QTc changes following typical systemic exposure and with markedly higher exposures, respectively. This was a four-way crossover study with 48 subjects randomly assigned to receive therapeutic and supratherapeutic doses of tedizolid phosphate, moxifloxacin (positive control for QT interval prolongation) and placebo (negative control). A continuous 12-lead ECG was recorded from 1 h before drug administration to 23 h after administration. Adverse events, which were generally mild, occurred most frequently with moxifloxacin or with a supratherapeutic dose of tedizolid phosphate; however, all treatments were well tolerated. This study demonstrated that therapeutic or supratherapeutic doses of the antibacterial tedizolid had no clinically significant effect on QT interval in healthy adults [ClinicalTrials.gov registration no.: NCT01461460].

α-Linolenic Acid, A Nutraceutical with Pleiotropic Properties That Targets Endogenous Neuroprotective Pathways to Protect against Organophosphate Nerve Agent-Induced Neuropathology.

α-Linolenic acid (ALA) is a nutraceutical found in vegetable products such as flax and walnuts. The pleiotropic properties of ALA target endogenous neuroprotective and neurorestorative pathways in brain and involve the transcription factor nuclear factor kappa B (NF-κB), brain-derived neurotrophic factor (BDNF), a major neuroprotective protein in brain, and downstream signaling pathways likely mediated via activation of TrkB, the cognate receptor of BDNF. In this review, we discuss possible mechanisms of ALA efficacy against the highly toxic OP nerve agent soman. Organophosphate (OP) nerve agents are highly toxic chemical warfare agents and a threat to military and civilian populations. Once considered only for battlefield use, these agents are now used by terrorists to inflict mass casualties. OP nerve agents inhibit the critical enzyme acetylcholinesterase (AChE) that rapidly leads to a cholinergic crisis involving multiple organs. Status epilepticus results from the excessive accumulation of synaptic acetylcholine which in turn leads to the overactivation of muscarinic receptors; prolonged seizures cause the neuropathology and long-term consequences in survivors. Current countermeasures mitigate symptoms and signs as well as reduce brain damage, but must be given within minutes after exposure to OP nerve agents supporting interest in newer and more effective therapies. The pleiotropic properties of ALA result in a coordinated molecular and cellular program to restore neuronal networks and improve cognitive function in soman-exposed animals. Collectively, ALA should be brought to the clinic to treat the long-term consequences of nerve agents in survivors. ALA may be an effective therapy for other acute and chronic neurodegenerative disorders.

Tedizolid: a novel oxazolidinone with potent activity against multidrug-resistant gram-positive pathogens.

Tedizolid phosphate is a novel oxazolidinone prodrug (converted to the active form tedizolid by phosphatases in vivo) that has been developed and recently approved (June 2014) by the United States FDA for the treatment of acute bacterial skin and skin structure infections (ABSSSIs) caused by susceptible Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus (MRSA). Tedizolid is an oxazolidinone, but differs from other oxazolidinones by possessing a modified side chain at the C-5 position of the oxazolidinone nucleus which confers activity against certain linezolid-resistant pathogens and has an optimized C- and D-ring system that improves potency through additional binding site interactions. The mechanism of action of tedizolid is similar to other oxazolidinones and occurs through inhibition of bacterial protein synthesis by binding to 23S ribosomal RNA (rRNA) of the 50S subunit of the ribosome. As with other oxazolidinones, the spontaneous frequency of resistance development to tedizolid is low. Tedizolid is four- to eightfold more potent in vivo than linezolid against all species of staphylococci, enterococci, and streptococci, including drug-resistant phenotypes such as MRSA and vancomycin-resistant enterococci (VRE) and linezolid-resistant phenotypes. Importantly, tedizolid demonstrates activity against linezolid-resistant bacterial strains harboring the horizontally transmissible cfr gene, in the absence of certain ribosomal mutations conferring reduced oxazolidinone susceptibility. With its half-life of approximately 12 h, tedizolid is dosed once daily. It demonstrates linear pharmacokinetics, has a high oral bioavailability of approximately 90 %, and is primarily excreted by the liver as an inactive, non-circulating sulphate conjugate. Tedizolid does not require dosage adjustment in patients with any degree of renal dysfunction or hepatic dysfunction. Studies in animals have demonstrated that the pharmacodynamic parameter most closely associated with the efficacy of tedizolid is fAUC(0-24h)/MIC. In non-neutropenic animals, a dose-response enhancement was observed with tedizolid and lower exposures were required compared to neutropenic cohorts. Two Phase III clinical trials have demonstrated non-inferiority of a once-daily tedizolid 200 mg dose for 6-10 days versus twice-daily 600 mg linezolid for the treatment of ABSSSIs. Both trials used the primary endpoint of early clinical response at 48-72 h; however, one trial compared oral formulations while the other initiated therapy with the parenteral formulation and allowed oral sequential therapy following initial clinical response. Throughout its development, tedizolid has demonstrated that it is well tolerated and animal studies have shown a lower propensity for neuropathies with long-term use than its predecessor linezolid. Data from the two completed Phase III clinical trials demonstrated that the studied tedizolid regimen (200 mg once daily for 6 days) had significantly less impact on hematologic parameters as well as significantly less gastrointestinal treatment-emergent adverse effects (TEAEs) than its comparator linezolid. As with linezolid, tedizolid is a weak, reversible MAO inhibitor; however, a murine head twitch model validated to assess serotonergic activity reported no increase in the number of head twitches with tedizolid even at doses that exceeded the C max in humans by up to 25-fold. Tyramine and pseudoephedrine challenge studies in humans have also reported no meaningful MAO-related interactions with tedizolid. With its enhanced in vitro activity against a broad-spectrum of Gram-positive aerobic bacteria, convenient once-daily dosing, a short 6-day course of therapy, availability of both oral and intravenous routes of administration, and an adverse effect profile that appears to be more favorable than linezolid, tedizolid is an attractive agent for use in both the hospital and community settings. Tedizolid is currently undergoing additional Phase III clinical trials for the treatment of hospital-acquired bacterial pneumonia (HABP) and ventilated nosocomial pneumonia (VNP).

Auditory event-related potential changes in chronic occupational exposure to organophosphate pesticides.

OBJECTIVE: To determine whether chronic occupational exposure to organophosphates (OP) pesticides leads to cognitive impairment using event-related potentials (ERPs). METHODS: ERPs of 38 vegetable farmers applying OP pesticides and 35 controls were recorded using an auditory oddball paradigm. The N1, P2, N2 and P300 ERP components and the number of counting errors were compared between the groups. RESULTS: The farmers made significantly more counting errors than controls in the oddball task. The mixed model ANOVA of component latencies revealed a significant componentxgroup interaction, suggesting farmers had a greater delay in later ERP components. Intergroup comparisons of individual components showed significant delays in N2 and P300 latencies. Subsequent ANCOVA showed significant P300 delay even after adjusting for the latency of the preceding component, N2. Intergroup differences of P300 amplitudes were not significant, although there was limited evidence of a difference in scalp topography. CONCLUSION: Our findings indicate that chronic low-level occupational exposure to OP pesticides is associated with progressively increasing delay in successive ERP components, particularly P300. SIGNIFICANCE: Chronic exposure to OP pesticides may delay the neurophysiological processes underlying early stages of selective attention and late stages of sensory information processing that include stimulus evaluation and updating of working memory.

Specification of the structure of oximes able to reactivate tabun-inhibited acetylcholinesterase.

The efficacy of various oximes to reactivate acetylcholinesterase phosphorylated by tabun (O-ethyl-N,N-dimethyl phosphoramidocyanidate) was tested by in vitro and in vivo methods. The oximes commonly used for the treatment of acute poisonings with highly toxic organophosphates appeared to be almost ineffective (HI-6, pralidoxime, methoxime) or just slightly effective (obidoxime) against tabun. On the other hand, trimedoxime seemed to be a significantly more efficacious reactivator than the others in the case of tabun poisonings. In vitro, the concentration of trimedoxime corresponding to 1.0 mmol/l was able to reach 50% reactivation of tabun-inhibited brain acetylcholinesterase. Higher reactivating potency of trimedoxime in comparison with the other commonly used oximes was demonstrated by in vivo method, too. In addition, other structural analogues of trimedoxime were found to be efficacious in counteracting tabun-induced acetylcholinesterase inhibition although not as efficacious as trimedoxime itself. Some effective acetylcholinesterase reactivators were characterised by dissociation constant of enzyme-reactivator complex as well as enzyme-inhibitor-reactivator complex and by rate constant of reactivation.