In vitro and in vivo investigation of a thyroid hormone system-specific interaction with triazoles.

Alterations in thyroid hormones (TH) and thyroid-stimulating hormone levels are frequently found following exposure to chemicals of concern. Dysregulation of TH levels can severely perturb physiological growth, metabolism, differentiation, homeostasis in the adult and developmental processes in utero. A frequently identified mode of action for this interaction is the induction of hepatic detoxification mechanisms (e.g. SULTs and UGTs), which lead to TH conjugation and elimination and therefore interfere with hormonal homeostasis, fulfilling the endocrine disruptors (EDs) definition. A short-term study in rats with dietary exposure to cyproconazole, epoxiconazole and prochloraz was conducted and hepatocyte hypertrophy, hepatic UGT activity and Phase 1/2 gene expression inductions were observed together with changes in TH levels and thyroid follicular hypertrophy and hyperplasia. To test for specific interaction with the thyroid hormone system, in vitro assays were conducted covering thyroidal I-uptake (NIS), TH transmembranal transport via MCT8 and thyroid peroxidase (TPO) function. Assays for iodothyronine deiodinases (DIO1-DIO3) and iodotyrosine deiodinase (DEHAL1) were included, and from the animal experiment, Dio1 and Dehal1 activities were measured in kidney and liver as relevant local indicators and endpoints. The fungicides did not affect any TH-specific KEs, in vitro and in vivo, thereby suggesting hepatic conjugation as the dominant MoA.

Matrine and Oxymatrine: evaluating the gene mutation potential using in silico tools and the bacterial reverse mutation assay (Ames test).

The quinolizidine alkaloids matrine and its N-oxide oxymatrine occur in plants of the genus Sophora. Recently, matrine was sporadically detected in liquorice products. Morphological similarity of the liquorice plant Glycyrrhiza glabra with Sophora species and resulting confusion during harvesting may explain this contamination, but use of matrine as pesticide has also been reported. The detection of matrine in liquorice products raised concern as some studies suggested a genotoxic activity of matrine and oxymatrine. However, these studies are fraught with uncertainties, putting the reliability and robustness into question. Another issue was that Sophora root extracts were usually tested instead of pure matrine and oxymatrine. The aim of this work was therefore to determine whether matrine and oxymatrine have potential for causing gene mutations. In a first step and to support a weight-of-evidence analysis, in silico predictions were performed to improve the database using expert and statistical systems by VEGA, Leadscope (Instem®), and Nexus (Lhasa Limited). Unfortunately, the confidence levels of the predictions were insufficient to either identify or exclude a mutagenic potential. Thus, in order to obtain reliable results, the bacterial reverse mutation assay (Ames test) was carried out in accordance with OECD Test Guideline 471. The test set included the plate incorporation and the preincubation assay. It was performed with five different bacterial strains in the presence or absence of metabolic activation. Neither matrine nor oxymatrine induced a significant increase in the number of revertants under any of the selected experimental conditions. Overall, it can be concluded that matrine and oxymatrine are unlikely to have a gene mutation potential. Any positive findings with Sophora extracts in the Ames test may be related to other components. Notably, the results also indicated a need to extend the application domain of respective (Q)SAR tools to secondary plant metabolites.

Effects of co-formulants on the absorption and secretion of active substances in plant protection products in vitro.

Currently, the authorisation process for plant protection products (PPPs) relies on the testing of acute and topological toxicity only. Contrastingly, the evaluation of active substances includes a more comprehensive set of toxicity studies. Nevertheless, mixture effects of active ingredients and co-formulants may result in increased toxicity. Therefore, we investigated effects of surface active co-formulants on the toxicity of two PPPs focussing on qualitative and quantitative toxicokinetic effects on absorption and secretion. The respective products are based on the active substances abamectin and fluroxypyr-meptyl and were tested for cytotoxicity in the presence or absence of the corresponding surfactants and co-formulants using Caco-2 cells. In addition, the effect of co-formulants on increased cellular permeation was quantified using LC-MS/MS, while potential kinetic mixture effects were addressed by fluorescence anisotropy measurements and ATPase assays. The results show that surface active co-formulants significantly increase the cytotoxicity of the investigated PPPs, leading to more than additive mixture effects. Moreover, analytical investigations show higher efflux ratios of both active substances and the metabolite fluroxypyr upon combination with certain concentrations of the surfactants. The results further point to a significant and concentration-dependent inhibition of Pgp transporters by most of the surfactants as well as to increased membrane fluidity. Altogether, these findings strongly support the hypothesis that surfactants contribute to increased cytotoxicity of PPPs and do so by increasing the bioavailability of the respective active substances.

Early implementation of continuous renal replacement therapy optimizes casualty evacuation for combat-related acute kidney injury.

BACKGROUND: The purpose of this report was to review the initial use and feasibility of continuous renal replacement therapy (CRRT) among combat casualties in a war zone. Although rapid evacuation to more advanced levels of care has emerged as the standard approach, life-threatening sequelae of acute kidney injury (AKI) can preclude safe patient evacuation. For the first time in US combat casualty care, a sustained, intensivist-led CRRT program was initiated during 2010 at an Air Force theater hospital. METHODS: A prospective study of consecutive US service members (USSMs) who developed combat-related renal failure and underwent CRRT at the Craig Joint Theater Hospital was undertaken. Baseline patient characteristics, indications for CRRT, laboratory values, and outcomes were evaluated. RESULTS: Nine USSMs were treated during 14-months. All were male, with a mean (SD) age of 28 (7) years and mean (SD) Injury Severity Score (ISS) of 34 (12). The dominant mechanism was blast injury (8 of 9), followed by gunshot wound (1 of 9). Most patients were Acute Kidney Injury Network (AKIN) 3 and all developed critical hyperkalemia (mean [SD], peak K⁺ 6.4 [0.4]). The peak plasma creatinine ranged from 1.4 mg/dL to 4.2 mg/dL (mean [SD], 3.3 [0.9] mg/dL). Patients had a mean (SD) of 17.6 [8.1] hours of CRRT before evacuation to higher echelons of care. All USSMs survived to achieve safe evacuation from the combat zone to the regional trauma center in Landstuhl, Germany (Landstuhl Regional Medical Center). Three patients died of multiorgan failure at Landstuhl Regional Medical Center. Six patients survived to undergo additional treatment in the United States. CONCLUSION: Intensivist-led CRRT is an effective therapeutic adjunct in the treatment of combat-related AKI. Provision of this extracorporeal therapy provides physiologic stabilization of casualties who might otherwise succumb to the sequelae of combat-related renal failure. These findings suggest that a self-sustaining CRRT program can be successfully implemented in combat support hospitals.