Evidence for the systemic diffusion of (2-chloroethyl)-ethyl-sulfide, a sulfur mustard analog, and its deleterious effects in brain.

Sulfur mustard, a chemical warfare agent known to be a vesicant of skin, readily diffuses in the blood stream and reaches internal organs. In the present study, we used the analog (2-chloroethyl)-ethyl-sulfide (CEES) to provide novel data on the systemic diffusion of vesicants and on their ability to induce brain damage, which result in neurological disorders. SKH-1 hairless mice were topically exposed to CEES and sacrificed at different time until 14 days after exposure. A plasma metabolomics study showed a strong systemic impact following a self-protection mechanism to alleviate the injury of CEES exposure. This result was confirmed by the quantification of specific biomarkers in plasma. Those were the conjugates of CEES with glutathione (GSH-CEES), cysteine (Cys-CEES) and N-acetyl-cysteine (NAC-CEES), as well as the guanine adduct (N7Gua-CEES). In brain, N7Gua-CEES could be detected both in DNA and in organ extracts. Similarly, GSH-CEES, Cys-CEES and NAC-CEES were present in the extracts until day14. Altogether, these results, based on novel exposure markers, confirm the ability of vesicants to induce internal damage following dermal exposure. The observation of alkylation damage to glutathione and DNA in brain provides an additional mechanism to the neurological insult of SM.

Enantioselective in-vitro elimination kinetics of nerve agents in blood monitored by derivatization and LC-MS/MS analysis.

We present a simple method for chiral separation and analysis of organophosphorus nerve agents and apply it to monitor the enantioselective blood elimination kinetics of sarin in-vitro. The method is implemented in standard reverse phase LC-MS operating conditions, relieving the user of the dedicated operating conditions frequently demanded in chiral LC-MS analysis. The method consists of formation of diastereomers by a rapid derivatization with (R)-2-(1 aminoethyl) phenol, followed by LC-MS/MS analysis. Derivatization enantioselectivity was studied by comparing the reaction of optically pure sarin and racemic sarin, proving no substantial enantiomeric preference in the reaction and demonstrating the enantiomeric discrimination abilities of the technique. Enantioselective sarin elimination pathways were probed in-vitro by following the fast elimination kinetics of the two sarin enantiomers as well as its hydrolysis metabolite (isopropyl methyl-phosphonic acid, IMPA) in whole blood and plasma compared to water. Sarin enantiomers showed the known marked differences in elimination kinetics with rapid elimination of the (+) enantiomer and slower elimination of the (-) enantiomer in whole blood and plasma as well as dose-dependent kinetics (faster elimination at lower concentrations). We found that small amounts of acetonitrile in plasma prevent the rapid elimination of the (+) enantiomer, resulting in similar, slower elimination kinetics for both enantiomers.

Pharmacokinetics of K117 and K127, two novel antidote candidates to treat Tabun poisoning.

AIMS: K117 and K127 are bis-pyridinium aldoximes but K117 is a bis-pyridinium bis-aldoxime while K127 has only one single aldoxime in addition to its amide substituent. Is there any difference in pharmacokinetics in these compounds that otherwise have the same chemical structure? Both K117 and K127 are developed as antidotes in acetylcholinesterase and butyrylcholinesterase poisoning in terrorist attacks or intoxication with other organophosphorous compounds. Their distributions have been scouted in the bodies of rats. MAIN METHODS: White male Wistar rats were intramuscularly injected. The animals were sacrificed, tissue samples were homogenized, and either K117 or K127 concentrations were determined using reversed-phase high-performance liquid chromatography. KEY FINDINGS: Both K117 and K127 were present in all tissues that were analyzed including blood (serum), the brains, cerebrospinal fluid, the eyes, livers, kidneys, lungs and testes. Their pharmacokinetics and body distributions are similar. SIGNIFICANCE: Either K117 or K127 meets the essential requirements for antidotes. Dose dependence and kinetics of their distribution were compared to that of other pyridinium aldoximes.

In vitro human skin permeation and decontamination of diisopropyl methylphosphonate (DIMP) using Dermal Decontamination Gel (DDGel) and Reactive Skin Decontamination Lotion (RSDL) at different timepoints.

This study compared the efficiency for in vitro human skin decontamination using DDGel and RSDL when applied at different timepoints (5 min and 90 min). Experiments were performed using in vitro human skin models, in which skin was mounted onto Flow-Through diffusion cells. The mass of 14-C DIMP removed from skin surface after decontamination was quantitated by measuring radioactivity with a liquid scintillation spectrometer. Both decontaminants removed more than 90% recovery dose of DIMP from skin compared to control group (p < 0.05). DDGel skin decontamination reduced more toxicant amount when compared to RSDL. DDGel showed slight higher decontamination ability of DIMP than RSDL and efficiently removed chemicals from the skin surface, also reduced the amount of DIMP in receptor fluid. A similar decontamination regimen with RSDL and DDGel at 90 min showed that both were still might effectively increase the time window of opportunity for treatment. Thus, DDGel can offer a potential as a next generation skin decontamination platform technology for military and civilian applications.

pH-Dependent Piecewise Linear Correlation of 1H,31P Chemical Shifts: Application in NMR Identification of Nerve Agent Metabolites in Urine Samples.

The NMR-observable nuclei of the acidic and basic compounds experience pH dependence in chemical shift. This phenomenon can be exploited in NMR titrations to determine p Ka values of compounds, or in pH measurement of solutions using dedicated pH reference compounds. On the other hand, this sensitivity can also cause problems in, for example, metabolomics, where slight changes in pH result in significant difficulties for peak alignment between spectra of set of samples for comparative analysis. In worst case, the pH sensitivity of chemical shifts can prevent unambiguous identification of compounds. Here, we propose an alternative approach for NMR identification of pH-sensitive analytes. The 1H and X (13C, 15N, 31P, ...) chemical shifts in close proximity to the acidic or basic functional group should, when presented as ordered pairs, express piecewise linear correlation with distinct slope, intercept, and range. We have studied the pH dependence of 1H and 31P chemical shifts of the CH3-P moiety in urinary metabolites of nerve agents sarin, soman and VX using 2D 1H-31P fast-HMQC spectroscopy. The 1H and 31P chemical shifts of these chemicals appear in very narrow range, and due to subtle changes in sample pH the identification on either 1H or 31P chemical shift alone is uncertain. However, if the observed 1H and 31P chemical shifts of the CH3-P moiety of individual compounds are presented as ordered pairs, they fall into distinct linear spaces, thus, facilitating identification with high confidence.

Dermatotoxicology of sulfur mustard: Historical perspectives from World War I.

Sulfur mustard has been used as a chemical warfare agent for the past century. After its introduction by the Germans in World War I, investigators quickly began studying its impact on the human body including its deleterious effects on skin. This review focuses on two groups in particular who conducted experiments from 1917 to 1918: the United States Army at the American University Experiment Station Laboratories and Torald Sollmann at Western Reserve University. Through this work, these researchers proved far ahead of their time by anticipating dermatologic phenomena not described in the literature until later in the twentieth century. These include regional variation of percutaneous penetration, effect of vehicle on penetration and predicting immunologic contact urticaria. The work conducted by these researchers set the groundwork for much of twentieth century dermatotoxicology.

The percutaneous absorption of soman in a damaged skin porcine model and the evaluation of WoundStat™ as a topical decontaminant.

PURPOSE: The aim of this study was to evaluate a candidate haemostat (WoundStat™), down-selected from previous in vitro studies, for efficacy as a potential skin decontaminant against the chemical warfare agent pinacoyl methylfluorophosphonate (Soman, GD) using an in vivo pig model. MATERIALS AND METHODS: An area of approximately 3 cm2 was dermatomed from the dorsal ear skin to a nominal depth of 100 µm. A discrete droplet of 14C-GD (300 µg kg-1) was applied directly onto the surface of the damaged skin at the centre of the dosing site. Animals assigned to the treatment group were given a 2 g application of WoundStat™ 30 s after GD challenge. The decontamination efficacy of WoundStat™ against GD was measured by the direct quantification of the distribution of 14C-GD, as well as routine determination of whole blood cholinesterase and physiological measurements. RESULTS: WoundStat™ sequestered approximately 70% of the applied 14C-GD. Internal radiolabel recovery from treated animals was approximately 1% of the initially applied dose. Whole blood cholinesterase levels decreased to less than 10% of the original value by 15 min post WoundStat™ treatment and gradually decreased until the onset of apnoea or until euthanasia. All treated animals showed signs of GD intoxication that could be grouped into early (mastication, fasciculations and tremor), intermediate (miosis, salivation and nasal secretions) and late onset (lacrimation, body spasm and apnoea) effects. Two of the six WoundStat™ treated animals survived the study duration. CONCLUSIONS: The current study has shown that the use of WoundStat™ as a decontaminant on damaged pig ear skin was unable to fully protect against GD toxicity. Importantly, the findings indicate that the use of WoundStat™ in GD contaminated wounds would not exacerbate GD toxicity. These data suggest that absorbent haemostatic products may offer some limited functionality as wound decontaminants.

Online coupling of immunoextraction, digestion, and microliquid chromatography-tandem mass spectrometry for the analysis of sarin and soman-butyrylcholinesterase adducts in human plasma.

Organophosphorus nerve agent (OPNA) adducts formed with human butyrylcholinesterase (HuBuChE) can be used as biomarker of OPNA exposure. Indeed, intoxication by OPNAs can be confirmed by the LC/MS2 analysis of a specific HuBuChE nonapeptide on which OPNAs covalently bind. A fast, selective, and highly sensitive online method was developed to detect sarin and soman adducts in plasma, including immunoextraction by anti-HuBuChE antibodies, pepsin digestion on immobilized enzyme reactors (IMER), and microLC/MS2 analysis of the OPNA adducts. The potential of three different monoclonal antibodies, covalently grafted on sepharose, was compared for the extraction of HuBuChE. The online method developed with the most promising antibodies allowed the extraction of up to 100% of HuBuChE contained in plasma and the digestion of 45% of it in less than 40 min. Moreover, OPNA-HuBuChE adducts, aged OPNA adducts, and unadducted HuBuChE could be detected (with S/N > 2000), even in plasma spiked with a low concentration of OPNA (10 ng mL-1). Finally, the potential of this method was compared to approaches involving other affinity sorbents, already described for HuBuChE extraction. Graphical abstract Online coupling of immunoextraction, digestion, and microliquid chromatography-tandem mass spectrometry for the analysis of organophosphorous nerve agent adducts formed with human butyrylcholinesterase.

Sulfur mustard skin lesions: A systematic review on pathomechanisms, treatment options and future research directions.

Sulfur mustard (SM) is a chemical warfare, which has been used for one hundred years. However, its exact pathomechanisms are still incompletely understood and there is no specific therapy available so far. In this systematic review, studies published between January 2000 and July 2017 involving pathomechanisms and experimental treatments of SM-induced skin lesions were analyzed to summarize current knowledge on SM pathology, to provide an overview on novel treatment options, and to identify promising targets for future research to more effectively counter SM effects. We suggest that future studies should focus on (I) systemic effects of SM intoxication due to its distribution throughout the body, (II) removal of SM depots that continuously release active compound contributing to chronic skin damage, and (III) therapeutic options that counteract the pleiotropic effects of SM.

Biological effects of adipocytes in sulfur mustard induced toxicity.

Sulphur mustard (2,2'-dichloroethyl sulfide; SM) is a vesicant chemical warfare agent whose mechanism of acute or chronic action is not known with any certainty and to date there is no effective antidote. SM accumulation in adipose tissue (AT) has been originally verified in our previous study. To evaluate the biological effect caused by the presence of abundant SM in adipocyte and assess the biological role of AT in SM poisoning, in vitro and in vivo experiments were performed. High content analysis revealed multi-cytotoxicity in SM exposed cells in a time and dose dependent manner, and adipocytes showed a relative moderate damage compared with non-adipocytes. Cell co-culture model was established and revealed the adverse effect of SM-exposed adipocyte supernatant on the growth of co-cultured cells. The pathological changes in AT from 10mg/kg SM percutaneously exposed rats were checked and inflammation phenomena were observed. The mRNA and protein levels of inflammation-related adipokines secreted from AT in rats exposed to 1, 3 and 10mg/kg doses of SM were determined by reverse transcriptase-polymerase chain reaction and enzyme-linked immunosorbent assays. The expressions of proinflammatory and anti-inflammatory adipokines together promoted the inflammation development in the body. The positive correlations between AT and serum adipokine levels were explored, which demonstrated a substantial role of AT in systemic inflammation responding to SM exposure. Thus, AT is not only a target of SM but also a modulator in the SM toxicity.

The percutaneous toxicokinetics of VX in a damaged skin porcine model and the evaluation of WoundStat™ as a topical decontaminant.

This study used a damaged skin, porcine model to evaluate the in vivo efficacy of WoundStat™ for the decontamination of superficial, nerve agent-contaminated wounds. Anaesthetized animals were randomly assigned to either control (n = 7), no decontamination (n = 12) or WoundStat™ (n = 12) treatment groups. Pigs were exposed to a 5× LD50 dose of neat, radiolabelled S-[2-(diisopropylamino)ethyl]-O-ethyl methyl-phosphonothioate (VX; or equivalent volume of sterile saline for the control group) via an area of superficially damaged skin on the ear. WoundStat™ was applied at 30 seconds post-exposure to assigned animals. The VX contaminant (or saline) and decontaminant remained in place for the duration of the study (up to 6 hours). Physiological parameters and signs of intoxication were recorded during the exposure period. Skin and organ samples were taken post mortem for 14 C-VX distribution analyses. Blood samples were taken periodically for toxicokinetic and whole-blood acetylcholinesterase (AChE) activity analyses. VX exposure was accompanied by a rapid decrease in AChE activity in all animals, regardless of decontamination. However, decontamination significantly improved survival rate and time and reduced the severity of signs of intoxication. In addition, the distribution of 14 C-VX in key internal organs and post mortem blood samples was significantly lower in the WoundStat™ treatment group. This study demonstrates that WoundStat™ may be a suitable medical countermeasure for increasing both survival rate and time following VX exposure. The results also suggest that AChE activity is not a useful prognostic indicator.

Comparison of four different fuller's earth formulations in skin decontamination.

Industrial accidents, wars and terrorist threats are potential sources of skin contamination by highly toxic chemical warfare agents and manufacturing compounds. We have compared the time-dependent adsorption capacity and decontamination efficiency of fuller's earth (FE) for four different formulations for the molecular tracer, 4-cyanophenol (4-CP), in vitro and ex vivo using water decontamination as standard. The adsorption capacity of FE was assessed in vitro for 4-CP aqueous solutions whereas decontamination efficiency was investigated ex vivo by tracking porcine skin 4-CP content using attenuated total reflectance Fourier transform infrared spectroscopy. Decontamination was performed on short time, exposed porcine skin to 4-CP by application of FE: (1) as free powder; (2) loaded on adhesive tape; (3) on powdered glove; or (4) in suspension. Removal rate of 4-CP from aqueous solutions correlates with the amount of FE and its contact time. Decontamination efficiency estimated by the percentage of 4-CP recovery from contaminated porcine skin, achieved 54% with water, ranged between ~60 and 70% with dry FE and reached ~90% with FE suspension. Successful decontamination of the FE suspension, enabling a dramatic reduction of skin contamination after a brief exposure scenario, appears to be rapid, reliable and should be formulated in a new device ready to use for self-application.

The percutaneous toxicokinetics of Sulphur mustard in a damaged skin porcine model and the evaluation of WoundStat™ as a topical decontaminant.

This study used a damaged skin, porcine model to evaluate the in vivo efficacy of WoundStat™ for decontamination of superficial (non-haemorrhaging), sulphur mustard-contaminated wounds. The dorsal skin of 12 female pigs was subjected to controlled physical damage and exposed to 10 µL 14 C-radiolabelled sulphur mustard (14 C-SM). Animals were randomly assigned to either a control or a treatment group. In the latter, WoundStat™ was applied 30 s post exposure and left in situ for 1 h. Skin lesion progression and decontaminant efficacy were quantified over 6 h using a range of biophysical measurements. Skin, blood and organ samples were taken post mortem for histopathological assessment, 14 C-SM distribution and toxicokinetic analyses. Application of SM to damaged skin without decontamination was rapidly followed by advanced signs of toxicity, including ulceration and decreased blood flow at the exposure site in all animals. WoundStat™ prevented ulceration and improved blood flow at the exposure site in all decontaminated animals (n = 6). Furthermore, significantly smaller quantities of 14 C-SM were detected in the blood (45% reduction), and recovered from skin (70% reduction) and skin surface swabs (99% reduction) at 6 h post-challenge. Overall, the distribution of 14 C-SM in the internal organs was similar for both groups, with the greatest concentration in the kidneys, followed by the liver and small intestine. WoundStat™ significantly reduced the amount of 14 C-SM recovered from the liver, a key organ for SM metabolism and detoxification. This study demonstrates that WoundStat™ is a suitable product for reducing the ingress and toxicity of a chemical warfare agent. Copyright © 2017 John Wiley & Sons, Ltd.

Accumulation of intact sulfur mustard in adipose tissue and toxicokinetics by chemical conversion and isotope-dilution liquid chromatography-tandem mass spectrometry.

Sulfur mustard (SM) is a powerful vesicant and one of the most harmful chemical warfare agents. Although having been studied for a long time, it is still difficult to fully elucidate the mechanisms of SM poisoning, and there is no effective antidote or specific treatment for SM injury. The investigations on toxicokinetics and tissue distribution of SM will help to understand its toxicity and provide a theoretical basis for pretreatment and therapy of SM poisoning. But the metabolic trajectory or fate of intact SM in vivo remains unclear, and there are insufficient experimental data to elucidate, due to its high reactivity and difficulty in biomedical sample analysis. In this paper, a sensitive method for the detection and quantification of intact SM in blood or tissues using isotope-dilution LC-MS/MS coupled with chemical conversion was developed. By transforming highly reactive SM into stable derivative product, the real concentration of intact SM in biological samples was obtained accurately. The toxicokinetics and tissue distribution studies of intact SM in rats were successfully profiled by the novel method after intravenous (10 mg/kg) or cutaneous administration (1, 3 and 10 mg/kg). The SM level in blood with peak time at 30-60 min determined in cutaneous exposure experiment was found much higher than previously reported, and the mean residence time in blood extended to 1-1.5 h. A significant accumulation of intact SM was observed in adipose tissues, including the perirenal fat, epididymal fat, subcutaneous fat and brown fat, in which the concentrations of SM were at least 15 times greater than those in non-adipose tissues in cutaneous exposed rats. The recovery of SM in body fat was calculated as 3.3 % of bioavailable SM (the bioavailability after cutaneous exposure was evaluated as 16 %). Thus, the adipose tissue was important for SM distribution and toxicity, which may pioneer a new model for both the prevention and treatment of SM exposure.

A graphene oxide-based strand displacement amplification platform for ricin detection using aptamer as recognition element.

The toxic plant protein ricin is a potential agent for criminal or bioterrorist attacks due to the wide availability and relative ease of preparation. Herein, we developed a novel strategy for the detection of ricin B-chain (RTB) based on isothermal strand-displacement polymerase reaction (ISDPR) by using aptamer as a recognition element and graphene oxide (GO) as a low background platform. In this method, ricin-binding aptamer (RBA) hybridized with a short blocker firstly, and then was immobilized on the surface of streptavidin-coated magnetic beads (MBs). The addition of RTB could release the blocker, which could hybridize with the dye-modified hairpin probe and trigger the ISDPR, resulting in high fluorescence intensity. In the absence of RTB, however, the fluorescence of the dye could be quenched strongly by GO, resulting in the extremely low background signal. Thus, RTB could be sensitively detected by the significantly increased fluorescence signal. The linear range of the current analytical system was from 0.75µg/mL to 100µg/mL and the limit of detection (3σ) was 0.6µg/mL. This method has been successfully utilized for the detection of both the RTB and the entire ricin toxin in real samples, and it could be generalized to any kind of target detection based on an appropriate aptamer.

Simultaneous quantification of soman and VX adducts to butyrylcholinesterase, their aged methylphosphonic acid adduct and butyrylcholinesterase in plasma using an off-column procainamide-gel separation method combined with UHPLC-MS/MS.

This work describes a novel and sensitive non-isotope dilution method for simultaneous quantification of organophosphorus nerve agents (OPNAs) soman (GD) and VX adducts to butyrylcholinesterase (BChE), their aged methylphosphonic acid (MeP) adduct and unadducted BChE in plasma exposed to OPNA. OPNA-BChE adducts were isolated with an off-column procainamide-gel separation (PGS) from plasma, and then digested with pepsin into specific adducted FGES*AGAAS nonapeptide (NP) biomarkers. The resulting NPs were detected by UHPLC-MS/MS MRM. The off-column PGS method can capture over 90% of BChE, MeP-BChE, VX-BChE and GD-BChE from their respective plasma materials. One newly designed and easily synthesized phosphorylated BChE nonapeptide with one Gly-to-Ala mutation was successfully reported to serve as internal standard instead of traditional isotopically labeled BChE nonapeptide. The linear range of calibration curves were from 1.00-200ngmL-1 for VX-NP, 2.00-200ngmL-1 for GD-NP and MeP-NP (R2≥0.995), and 3.00-200ngmL-1 for BChE NP (R2≥0.990). The inter-day precision had relative standard deviation (%RSD) of <8.89%, and the accuracy ranged between 88.9-120%. The limit of detection was calculated to be 0.411, 0.750, 0.800 and 1.43ngmL-1 for VX-NP, GD-NP, MeP-NP and BChE NP, respectively. OPNA-exposed quality control plasma samples were characterized as part of method validation. Investigation of plasma samples unexposed to OPNA revealed no baseline values or interferences. Using the off-column PGS method combined with UHPLC-MS/MS, VX-NP and GD-NP adducts can be unambiguously detected with high confidence in 0.10ngmL-1 and 0.50ngmL-1 of exposed human plasma respectively, only requiring 0.1mL of plasma sample and taking about four hours without special sample preparation equipment. These improvements make it a simple, sensitive and robust PGS-UHPLC-MS/MS method, and this method will become an attractive alternative to immunomagnetic separation (IMS) method and a useful diagnostic tool for retrospective detection of OPNA exposure with high confidence. Furthermore, using the developed method, the adducted BChE levels from VX and GD-exposed (0.10-100ngmL-1) plasma samples were completely characterized, and the fact that VX being more active and specific to BChE than GD was re-confirmed.

Toxicology of organophosphorus compounds in view of an increasing terrorist threat.

The implementation of the Chemical Weapon Convention (CWC), prohibiting the development, production, storage and use of chemical weapons by 192 nations and the ban of highly toxic OP pesticides, especially class I pesticides according to the WHO classification, by many countries constitutes a great success of the international community. However, the increased interest of terrorist groups in toxic chemicals and chemical warfare agents presents new challenges to our societies. Almost seven decades of research on organophosphorus compound (OP) toxicology was mainly focused on a small number of OP nerve agents despite the fact that a huge number of OP analogues, many of these agents having comparable toxicity to classical nerve agents, were synthesized and published. Only limited physicochemical, toxicological and medical information on nerve agent analogues is available in the open literature. This implies potential gaps of our capabilities to detect, to decontaminate and to treat patients if nerve agent analogues are disseminated and may result in inadequate effectiveness of newly developed countermeasures. In summary, our societies may face new, up to now disregarded, threats by toxic OP which calls for increased awareness and appropriate preparedness of military and civilian CBRN defense, a broader approach for new physical and medical countermeasures and an integrated system of effective detection, decontamination, physical protection and treatment.

Simultaneous determination of sulfur mustard and related oxidation products by isotope-dilution LC-MS/MS method coupled with a chemical conversion.

Sulfur mustard (SM) is a highly reactive alkylating vesicant with high toxicity and complicated metabolism, the in vivo profile of its oxidation metabolism is not still fully known and urgently needs to be clarified well. In this work, an isotope-dilution high performance liquid chromatography-tandem mass spectrometric method coupled with chemical conversion was developed for the simultaneous quantification of SM and its oxidation products, i.e., mustard sulfoxide (SMO) and mustard sulfone (SMO2). The accurate measurement of SM and its oxidation products with high reaction activity was achived via the method of chemical conversion of 2-(3,5-bis(mercaptomethyl)phenoxy) acetic acid into stable derivative products. Method validation was performed in whole blood matrix, the linear range of the method was between 0.2 and 1000µg/L with correlation coefficients (r(2))>0.99, and the lower limits of quantification for SM, SMO and SMO2 were 1, 1, 0.2µg/L, respectively. The validated method was successfully applied to a toxicokinetics research of SM and its oxidation products after SM dermal exposed rats in a single dose. All three target analytes were found in whole blood samples from poisoned rats, and significant time-dependent responses were also observed. Among them, SMO2 with relatively high toxicity was identified and quantified in vivo for the first time, while SMO was the major product in whole blood and some of them continued to be oxidized to SMO2in vivo. These results give a direct experimental evidence to support that a large amount of SM is converted into the corresponding SMO and SMO2, and these oxidation products might cause potential combined toxic effects.

Rapid Detection of Ricin in Serum Based on Cu-Chelated Magnetic Beads Using Mass Spectrometry.

The protein toxin ricin obtained from castor bean plant (Ricinus communis) seeds is a potent biological warfare agent due to its ease of availability and acute toxicity. In this study, we demonstrated a rapid and simple method to detect ricin in serum in vitro. The ricin was mixed with serum and digested by trypsin, then all the peptides were efficiently extracted using Cu-chelated magnetic beads and were detected with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The specific ricin peptides were identified by Nanoscale Ultra Performance liquid chromatography coupled to tandem mass spectrometry according to their sequences. The assay required 2.5 hours, and a characteristic peptide could be detected down to 4 ng/µl and used as a biomarker to detect ricin in serum. The high sensitivity and simplicity of the procedure makes it valuable in clinical practice. Graphical Abstract ᅟ.

Effects of soap-water wash on human epidermal penetration.

Skin decontamination is a primary interventional method used to decrease dermal absorption of hazardous contaminants, including chemical warfare agents, pesticides and industrial pollutants. Soap and water wash, the most common and readily available decontamination system, may enhance percutaneous absorption through the "wash-in effect." To understand better the effect of soap-water wash on percutaneous penetration, and provide insight to improving skin decontamination methods, in vitro human epidermal penetration rates of four C(14) -labeled model chemicals (hydroquinone, clonidine, benzoic acid and paraoxon) were assayed using flow-through diffusion cells. Stratum corneum (SC) absorption rates of these chemicals at various hydration levels (0-295% of the dry SC weights) were determined and compared with the results of the epidermal penetration study to clarify the effect of SC hydration on skin permeability. Results showed accelerated penetration curves of benzoic acid and paraoxon after surface wash at 30 min postdosing. Thirty minutes after washing (60 min postdosing), penetration rates of hydroquinone and benzoic acid decreased due to reduced amounts of chemical on the skin surface and in the SC. At the end of the experiment (90 min postdosing), a soap-water wash resulted in lower hydroquinone penetration, greater paraoxon penetration and similar levels of benzoic acid and clonidine penetration compared to penetration levels in the non-wash groups. The observed wash-in effect agrees with the enhancement effect of SC hydration on the SC chemical absorption rate. These results suggest SC hydration derived from surface wash to be one cause of the wash-in effect. Further, the occurrence of a wash-in effect is dependent on chemical identity and elapsed time between exposure and onset of decontamination. By reducing chemical residue quantity on skin surface and in the SC reservoir, the soap-water wash may decrease the total quantity of chemical absorbed in the long term; however, the more immediate accelerated absorption of chemical toxins, particularly chemical warfare agents, may be lethal. Copyright © 2015 John Wiley & Sons, Ltd.