The extreme toxicity of nerve agents and the broad spectrum of their physical and chemical properties, enabling the use of these agents in a variety of tactical situations, is a continuing challenge in maintaining the knowledge and capability to detect them, as well as in finding new effective methods. Despite significant advances in the instrumentation of the analysis of nerve agents, relatively simple methods based on the evaluation of colour signals (absorption and fluorescence), in particular those using the cholinesterase reaction, continue to be of importance. This review provides a brief presentation of the current status of these simple methods, with an emphasis on military applications, and illustrates the high interest of the professional community in their further development. At the same time, it also contains some peculiarities (high reliability and durability, resistance to extreme climatic conditions, work in deployed means of protection, low purchase prices, economic availability especially in a state of war, etc.) that the authors believe research and development of simple methods and means for the detection of nerve agents should respect.
- MeSH
- cholinesterasy MeSH
- nervová bojová látka * analýza MeSH
- reprodukovatelnost výsledků MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
"Novichok" refers to a new group of nerve agents called the A-series agents. Their existence came to light in 2018 after incidents in the UK and again in 2020 in Russia. They are unique organophosphorus-based compounds developed during the Cold War in a program called Foliant in the USSR. This review is based on original chemical entities from Mirzayanov's memoirs published in 2008. Due to classified research, a considerable debate arose about their structures, and hence, various structural moieties were speculated. For this reason, the scientific literature is highly incomplete and, in some cases, contradictory. This review critically assesses the information published to date on this class of compounds. The scope of this work is to summarize all the available and relevant information, including the physicochemical properties, chemical synthesis, mechanism of action, toxicity, pharmacokinetics, and medical countermeasures used to date. The environmental stability of A-series agents, the lack of environmentally safe decontamination, their high toxicity, and the scarcity of information on post-contamination treatment pose a challenge for managing possible incidents.
- MeSH
- kontaminace léku * MeSH
- nervová bojová látka * toxicita MeSH
- organofosforové sloučeniny MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Organophosphorus compounds (OPs) involving life-threatening nerve agents (NA) have been known for several decades. Despite a clear mechanism of their lethality caused by the irreversible inhibition of acetylcholinesterase (AChE) and manifested via overstimulation of peripheral nicotinic and muscarinic acetylcholine (ACh) receptors, the mechanism for central neurotoxicity responsible for acute or delayed symptoms of the poisoning has not been thoroughly uncovered. One of the reasons is the lack of a suitable model. In our study, we have chosen the SH-SY5Y model in both the differentiated and undifferentiated state to study the effects of NAs (GB, VX and A234). The activity of expressed AChE in cell lysate assessed by Ellman's method showed 7.3-times higher activity in differentiated SH-SY5Y cells in contrast to undifferentiated cells, and with no involvement of BuChE as proved by ethopropazine (20 μM). The activity of AChE was found to be, in comparison to untreated cells, 16-, 9.3-, and 1.9-times lower upon A234, VX, and GB (100 μM) administration respectively. The cytotoxic effect of given OPs expressed as the IC50 values for differentiated and undifferentiated SH-SY5Y, respectively, was found 12 mM and 5.7 mM (A234), 4.8 mM and 1.1 mM (VX) and 2.6 mM and 3.8 mM (GB). In summary, although our results confirm higher AChE expression in the differentiated SH-SY5Y cell model, the such higher expression does not lead to a more pronounced NA cytotoxic effect. On the contrary, higher expression of AChE may attenuate NA-induced cytotoxicity by scavenging the NA. Such finding highlights a protective role for cholinesterases by scavenging Novichoks (A-agents). Second, we confirmed the mechanism of cytotoxicity of NAs, including A-agents, can be ascribed rather to the non-specific effects of OPs than to AChE-mediated effects.
Nerve agents have been used recently in the Syrian civil war. Collecting relevant samples for retrospective identification of an attack is often problematic. The article deals with the possibility of using contaminated gloves as an analytical sample for evidence of the chemical weapons use. There have not yet been published studies dealing with the identification of chemical warfare agents in this type of matrix, where the diversity of chemical properties of gloves and the lifetime of the contaminated sample would be considered. Sarin, soman, and cyclosarin were used as contaminants in the study. Nitrile, latex, and vinyl disposable gloves were chosen as matrices. The identification method was gas chromatography. Six solvents commonly used in military laboratories were tested as extractants. The extraction procedure was optimized in terms of the appropriate method (vortex) and the required extraction time (1 min) and resulted in significant reduction in sample preparation time. The chromatographic background of the extracts was also monitored in order to find a method with the least number of peaks interfering in the identification. Suitable solvents were hexane and acetonitrile. The lifetime of the sample was also investigated. The worst result was recorded for latex. For individual contaminants, the time varied depending on the volatility. The developed procedures were successfully validated within a sample handling effects scenario. The results demonstrate that in the event of an ongoing military risk at the site of an attack, even discarded disposable rubber glove type samples can be used as evidence.
- MeSH
- guma * chemie MeSH
- latex MeSH
- nervová bojová látka * MeSH
- ochranné rukavice MeSH
- retrospektivní studie MeSH
- rozpouštědla MeSH
- Publikační typ
- časopisecké články MeSH
- Klíčová slova
- autoinjektor,
- MeSH
- antidota * aplikace a dávkování terapeutické užití MeSH
- dějiny 20. století MeSH
- dějiny 21. století MeSH
- dějiny lékařství MeSH
- injekce metody MeSH
- lékové formy MeSH
- nervová bojová látka farmakologie MeSH
- Check Tag
- dějiny 20. století MeSH
- dějiny 21. století MeSH
- Publikační typ
- přehledy MeSH
The misuse of novichok agents in assassination attempts has been reported in the international media since 2018. These relatively new class of neurotoxic agents is claimed to be more toxic than the agents of the G and V series and so far, there is no report yet in literature about potential antidotes against them. To shed some light into this issue, we report here the design and synthesis of NTMGMP, a surrogate of A-242 and also the first surrogate of a novichok agent useful for experimental evaluation of antidotes. Furthermore, the efficiency of the current commercial oximes to reactivate NTMGMP-inhibited acetylcholinesterase (AChE) was evaluated. The Ellman test was used to confirm the complete inhibition of AChE, and to compare the subsequent rates of reactivation in vitro as well as to evaluate aging. In parallel, molecular docking, molecular dynamics and MM-PBSA studies were performed on a computational model of the human AChE (HssAChE)/NTMGMP complex to assess the reactivation performances of the commercial oximes in silico. Experimental and theoretical studies matched the exact hierarchy of efficiency and pointed to trimedoxime as the most promising commercial oxime for reactivation of AChE inhibited by A-242.
- MeSH
- acetylcholinesterasa MeSH
- antidota farmakologie MeSH
- cholinesterasové inhibitory toxicita MeSH
- lidé MeSH
- nervová bojová látka * toxicita MeSH
- oximy farmakologie MeSH
- reaktivátory cholinesterázy * farmakologie MeSH
- simulace molekulového dockingu MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
The fluorinated bis-pyridinium oximes were designed and synthesized with the aim of increasing their nucleophilicity and potential to reactivate phosphorylated human recombinant acetylcholinesterase (AChE) and human purified plasmatic butyrylcholinesterase (BChE) in relation to chlorinated and non-halogenated oxime analogues. Compared to non-halogenated oximes, halogenated oximes showed lower pKa of the oxime group (fluorinated < chlorinated < non-halogenated) along with higher level of oximate anion formation at the physiological pH, and had a higher binding affinity of both AChE and BChE. The stability tests showed that the fluorinated oximes were stable in water, while in buffered environment di-fluorinated oximes were prone to rapid degradation, which was reflected in their lower reactivation ability. Mono-fluorinated oximes showed comparable reactivation to non-halogenated (except asoxime) and mono-chlorinated oximes in case of AChE inhibited by sarin, cyclosarin, VX, and tabun, but were less efficient than di-chlorinated ones. The same trend was observed in the reactivation of inhibited BChE. The advantage of halogen substituents in the stabilization of oxime in a position optimal for in-line nucleophilic attack were confirmed by extensive molecular modelling of pre-reactivation complexes between the analogue oximes and phosphorylated AChE and BChE. Halogen substitution was shown to provide oximes with additional beneficial properties, e.g., fluorinated oximes gained antioxidative capacity, and moreover, halogens themselves did not increase cytotoxicity of oximes. Finally, the in vivo administration of highly efficient reactivator and the most promising analogue, 3,5-di-chloro-bispyridinium oxime with trimethylene linker, provided significant protection of mice exposed to sarin and cyclosarin.
- MeSH
- acetylcholinesterasa metabolismus MeSH
- butyrylcholinesterasa metabolismus MeSH
- cholinesterasové inhibitory chemie MeSH
- halogeny MeSH
- myši MeSH
- nervová bojová látka * farmakologie MeSH
- organofosforové sloučeniny MeSH
- oximy chemie MeSH
- reaktivátory cholinesterázy * chemie MeSH
- sarin chemie MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The nerve agents of the A-series are relatively recent chemical weapons with no antidote available yet. Once inside the human body, those chemicals act similarly to the classic nerve agents, by binding to the catalytic residue Serine 203 (Ser203) of human acetylcholinesterase (HssAChE) and thus preventing the proper function of this enzyme. However, there is no experimental evidence yet if the current antidotes for intoxication by nerve agents are also capable of restoring AChE inhibited by the nerve agents of the A-series. In order to launch some light on this issue, we used computational techniques (molecular docking, molecular dynamics and MM-PBSA interaction energy calculations) to assess the performances of the four currently available commercial oximes (2-PAM, HI-6, obidoxime and trimedoxime) when in contact with HssAChE inhibited by the agent A-242. Based on the near-attack conformation (NAC) criterion, our results suggest that the commercial oximes would have limited efficacy to reactivate the enzyme since they are not able to properly approach the adduct Ser203-A-242. Among those oximes, trimedoxime seems to be the most promising, since it showed lower values of energy in the MM-PBSA calculations, a higher stability inside the catalytic anionic center (CAS) of HssAChE, and was able to adopt a position closer to the NAC that could enable the reactivation mechanism.
- MeSH
- acetylcholinesterasa metabolismus MeSH
- antidota farmakologie MeSH
- cholinesterasové inhibitory chemie toxicita MeSH
- lidé MeSH
- nervová bojová látka * toxicita MeSH
- organofosfáty MeSH
- oximy chemie farmakologie MeSH
- pyridinové sloučeniny farmakologie MeSH
- reaktivátory cholinesterázy * farmakologie MeSH
- simulace molekulového dockingu MeSH
- trimedoxim farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Klíčová slova
- autoinjektor,
- MeSH
- antidota * aplikace a dávkování farmakologie terapeutické užití MeSH
- autoaplikace * MeSH
- diazepam aplikace a dávkování farmakologie terapeutické užití MeSH
- hypnotika a sedativa aplikace a dávkování farmakologie MeSH
- injekce intramuskulární MeSH
- lidé MeSH
- nervová bojová látka otrava MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- historické články MeSH
Pellets with an immobilized enzyme (acetyl- or butyrylcholinesterase) are the up-to-date type of carriers used for the detection of nerve agents (soman, sarin, tabun, VX, Novichok) and other cholinesterase inhibitors such as organophosphate and carbamate insecticides (parathion, malathion). They are used in the glass detection tubes as a layer containing the enzyme together with the second layer, which contains a colorimetric reagent and substrate. The detection method is based on the visually or spectrophotometrically observable Ellman's reaction, which develops a yellow color in the absence of the cholinesterase inhibitor; otherwise, the detector preserves its original color (preferably white). This reaction occurs very fast and has a high sensitivity to nerve agents but it suffers from an indistinctive color transition from white to yellow. In the presented study, a new approach with the use of the synergic effect of magnesium aluminometasilicate with a high surface area marketed as Neusilin®US2 and a protective semipermeable Eudragit® RL layer was utilized. The prepared pellets have been evaluated for their properties such as the activity of the enzyme, intensity of the developed yellow color, sensitivity to cholinesterase inhibitor physostigmine, which acts as a nerve agent simulant, and physical parameters such as hardness, pycnometric density and sphericity. After the initial evaluation, all samples underwent a stability test under three different storage conditions for 24 months during which they were evaluated at given time points (0, 3, 6, 12 and 24 months). It was found that the prepared samples achieved a much higher intensity of developed yellow color than in the published studies while maintaining similar or better sensitivity, speed of detection and suitable physico-chemical properties.
- MeSH
- acetylcholinesterasa chemie MeSH
- butyrylcholinesterasa chemie MeSH
- časové faktory MeSH
- cholinesterasové inhibitory analýza MeSH
- enzymy imobilizované chemie MeSH
- kolorimetrie metody MeSH
- nervová bojová látka analýza MeSH
- polymery chemie MeSH
- silikáty chemie MeSH
- sloučeniny hliníku chemie MeSH
- sloučeniny hořčíku chemie MeSH
- Publikační typ
- časopisecké články MeSH
