Drosophila melanogaster as a model organism for screening acetylcholinesterase reactivators.

Macedo PE ，Batista JES ，Souza LR ，Dafre AL ，Farina M ，Kuca K ，Posser T ，Pinto PM ，Boldo JT ，Franco JL ... -  《journal of toxicology and environmental health》

A-series agent A-234: initial in vitro and in vivo characterization.

A-series agent A-234 belongs to a new generation of nerve agents. The poisoning of a former Russian spy Sergei Skripal and his daughter in Salisbury, England, in March 2018 led to the inclusion of A-234 and other A-series agents into the Chemical Weapons Convention. Even though five years have already passed, there is still very little information on its chemical properties, biological activities, and treatment options with established antidotes. In this article, we first assessed A-234 stability in neutral pH for subsequent experiments. Then, we determined its inhibitory potential towards human recombinant acetylcholinesterase (HssAChE; EC 3.1.1.7) and butyrylcholinesterase (HssBChE; EC 3.1.1.8), the ability of HI-6, obidoxime, pralidoxime, methoxime, and trimedoxime to reactivate inhibited cholinesterases (ChEs), its toxicity in rats and therapeutic effects of different antidotal approaches. Finally, we utilized molecular dynamics to explain our findings. The results of spontaneous A-234 hydrolysis showed a slow process with a reaction rate displaying a triphasic course during the first 72 h (the residual concentration 86.2%). A-234 was found to be a potent inhibitor of both human ChEs (HssAChE IC50 = 0.101 ± 0.003 µM and HssBChE IC50 = 0.036 ± 0.002 µM), whereas the five marketed oximes have negligible reactivation ability toward A-234-inhibited HssAChE and HssBChE. The acute toxicity of A-234 is comparable to that of VX and in the context of therapy, atropine and diazepam effectively mitigate A-234 lethality. Even though oxime administration may induce minor improvements, selected oximes (HI-6 and methoxime) do not reactivate ChEs in vivo. Molecular dynamics implies that all marketed oximes are weak nucleophiles, which may explain the failure to reactivate the A-234 phosphorus-serine oxygen bond characterized by low partial charge, in particular, HI-6 and trimedoxime oxime oxygen may not be able to effectively approach the A-234 phosphorus, while pralidoxime displayed low interaction energy. This study is the first to provide essential experimental preclinical data on the A-234 compound.

Hrabinova M ，Pejchal J ，Hepnarova V ，Muckova L ，Junova L ，Opravil J ，Zdarova Karasova J ，Rozsypal T ，Dlabkova A ，Rehulkova H ，Kucera T ，Vecera Z ，Caisberger F ，Schmidt M ，Soukup O ，Jun D ... -  《-》

Halogenated monopyridinium oximes are less effective in reactivation of phosphylated cholinesterases than bisquaternary oximes.

Mono-quaternary pyridinium oximes derived from K-oximes K027, K048 and K203 were designed, synthesized and evaluated for the reactivation of organophosphate-inhibited cholinesterases. The incorporation of the halogen atoms to the structure decreased the pKa value of the oxime group resulting in an increased formation of oximate necessary for reactivation. The stability and pKa values were found to be similar to analogous bis-quaternary compounds. Some mono-quaternary oximes resulted as relatively strong inhibitors of human acetylcholinesterase. Nevertheless, the reactivation ability of mono-quaternary oximes for organophosphate-inhibited cholinesterases was lower compared to their bis-quaternary analogues. These results were further confirmed by the determination of reactivation kinetics, when in some cases novel compounds showed improvement reactivation compared to the tested standards, but no improvement to bis-quaternary K-oximes. A computational study investigated reactivation process for K027, and its two analogues for VX-inhibited AChE. This study revealed slight differences between reactivation of mono-quaternary and bis-quaternary oximes. Abbreviations: 2-PAM, pralidoxime; AChE, acetylcholinesterase; ACN, acetonitrile; ATCI, acetylcholine iodide; BChE, butyrylcholinesterase; BTCI, butyrylcholine iodide; Bu3SnSnBu3, bis(tributyltin) Et2O, diethyl ether; ChEs, cholinesterases; CNS, central nervous system; DAD, diode array detector; DIBAL-H, diisobutylaluminium hydride; DMF, dimethylformamide; DMSO, dimethyl sulfoxide; DTNB, 5,5́-dithiobis-2-nitrobenzoic acid; Et3N, triethylamine; EtOAc, ethyl acetate; EWG, electron withdrawing group; HI-6, asoxime; hrAChE, human recombinant acetylcholinesterase; hrBChE, human recombinant butyrylcholinesterase; hrChEs, human recombinant cholinesterases; HPLC, high-performance liquid chromatography; HRMS, high-resolution mass spectrometry; KD, dissociation constant; kr, first-order reactivation rate constant; kr2, second-order reactivation rate constant; LüH-6, obidoxime; MeOH, methanol; MM, molecular mechanics; MMC-4, methoxime; m.p., melting point; NCIs, non-covalent interactions; NEDPA, 4-nitrophenyl ethyl dimethylphosphoramidate; NEMP, 4-nitrophenyl ethyl methylphosphonate; NIMP, isopropyl methylphosphonate; NMR, nuclear magnetic resonance spectroscopy; OPs, organophosphates; PBS, phosphate-buffered saline; Pd(dppf)Cl2.CH2Cl2, [1,1'-Bis(diphenylphosphino)ferrocene]dichloropalladium(II) in complex with dichloromethane; pKa, negative decimal logarithm of the dissociation constant; POX, paraoxon; PPh3, triphenylphosphine; QM, quantum mechanics; rt, room temperature; SN2, bimolecular nucleophilic substitution; SNAc, nucleophilic acyl substitution; THF, tetrahydrofuran; TMC-4, trimedoxime; TNB, 5-thio-2-nitrobenzoic acid; UHPLC, ultra high-performance liquid chromatography; UV, ultraviolet; UV-VIS, ultraviolet-visible.

Kohoutova Z ，Prchalova E ，Andrys R ，Knittelova K ，Formanova M ，Hofmanova T ，Psotka M ，Musilek K ，Derat E ，Malinak D ... -  《-》

Synthesis and in vitro assessment of the reactivation profile of clinically available oximes on the acetylcholinesterase model inhibited by A-230 nerve agent surrogate.

The risk of the use of toxic chemicals for unlawful acts has been a matter of concern for different governments and multilateral agencies. The Organisation for the Prohibition of Chemical Weapons (OPCW), which oversees the implementation of the Chemical Weapons Convention (CWC), considering recent events employing chemical warfare agents as means of assassination, has recently included in the CWC "Annex on Chemicals" some organophosphorus compounds that are regarded as acting in a similar fashion to the classical G- and V-series of nerve agents, inhibiting the pivotal enzyme acetylcholinesterase. Therefore, knowledge of the activity of the pyridinium oximes, the sole class of clinically available acetylcholinesterase reactivators to date, is plainly justified. In this paper, continuing our research efforts in medicinal chemistry on this class of toxic chemicals, we synthesized an A-230 nerve agent surrogate and applied a modified Ellman's assay to evaluate its ability to inhibit our enzymatic model, acetylcholinesterase from Electrophorus eel, and if the clinically available antidotes are able to rescue the enzyme activity for the purpose of relating the findings to the previously disclosed in silico data for the authentic nerve agent and other studies with similar A-series surrogates. Our experimental data indicates that pralidoxime is the most efficient compound for reactivating acetylcholinesterase inhibited by A-230 surrogate, which is the opposite of the in silico data previously disclosed.

Bernardo LB ，Borges CVN ，Buitrago PAG ，Kuča K ，Cavalcante SFA ，Sousa RB ，Lima ALS ，Kitagawa DAS ... -  《-》

Qualitative evidence synthesis informing our understanding of people's perceptions and experiences of targeted digital communication.

Health communication is an area where changing technologies, particularly digital technologies, have a growing role to play in delivering and exchanging health information between individuals, communities, health systems, and governments.[1] Such innovation has the potential to strengthen health systems and services, with substantial investments in digital health already taking place, particularly in low‐ and middle‐income countries. Communication using mobile phones is an important way of contacting individual people and the public more generally to deliver and exchange health information. Such technologies are used increasingly in this capacity, but poor planning and short‐term projects may be limiting their potential for health improvement. The assumption that mobile devices will solve problems that other forms of communication have not is also prevalent. In this context, understanding people's views and experiences may lead to firmer knowledge on which to build better programs. A qualitative evidence synthesis by Heather Ames and colleagues on clients' perceptions and experiences of targeted digital communication focuses on a particular type of messaging – targeted messages from health services delivered to particular group(s) via mobile devices, in this case looking at communicating with pregnant women and parents of young children, and with adults and teenagers about sexual health and family planning.[2] These areas of reproductive, maternal, newborn, child, and adolescent health (RMNCAH) are where important gains have been made worldwide, but there remains room for improvement. Ames and colleagues sought to examine and understand people's perceptions and experiences of using digital targeted client communication. This might include communication in different formats and with a range of purposes related to RMNCAH – for example, receiving text message reminders to take medicines (e.g. HIV medicines) or go to appointments (such as childhood vaccination appointments), or phone calls offering information or education (such as about breastfeeding or childhood illnesses), support (e.g. providing encouragement to change behaviours) or advice (such as advising about local healthcare services). These communication strategies have the potential to improve health outcomes by communicating with people or by supporting behaviour change. However, changing people's health behaviours to a significant and meaningful degree is notoriously challenging and seldom very effective across the board. There are a multitude of systematic reviews of interventions aiming to change behaviours of both patients and providers, with the overall objective of improving health outcomes – many of which show little or no average effects across groups of people.[3] This evidence synthesis is therefore important as it may help to understand why communicating with people around their health might (or might not) change behaviours and improve consequent health outcomes. By examining the experiences and perspectives of those receiving the interventions, this qualitative evidence synthesis allows us to better understand the interventions' acceptability and usefulness, barriers to their uptake, and factors to be considered when planning implementation. The synthesis looked at 35 studies from countries around the world, focussing on communication related to RMNCAH. Of the 35 studies, 16 were from high‐income countries, mainly the United States, and 19 were from low‐ or middle‐income countries, mainly African countries. Many of the studies presented hypothetical scenarios. The findings from the synthesis are mixed and give us a more nuanced picture of the role of targeted digital communication. People receiving targeted digital communications from health services often liked and valued these contacts, feeling supported and connected by them. However, some also reported problems with the use of these technologies, which may represent barriers to their use. These included practical or technical barriers like poor network or Internet access, as well as cost, language, technical literacy, reading or issues around confidentiality, especially where personal health conditions were involved. Access to mobile phones may also be a barrier, particularly for women and adolescents who may have to share or borrow a phone or who have access controlled by others. In such situations it may be difficult to receive communications or to maintain privacy of content. The synthesis also shows that people's experiences of these interventions are influenced by factors such as the timing of messages, their frequency and content, and their trust in the sender. Identifying key features of such communications by the people who use them might therefore help to inform future choices about how and when such messaging is used. The authors used their knowledge from 25 separate findings to list ten implications for practice. This section of the review is hugely valuable, making a practical contribution to assist governments and public health agencies wishing to develop or improve their delivery of digital health. The implications serve as a list of points to consider, including issues of access (seven different aspects are considered), privacy and confidentiality, reliability, credibility and trust, and responsiveness to the needs and preferences of users. In this way, qualitative evidence is building a picture of how to better communicate with people about health. For example, an earlier 2017 Cochrane qualitative evidence synthesis by Ames, Glenton and Lewin on parents' and informal caregivers' views and experiences of communication about routine childhood vaccination provides ample evidence that may help program managers to deliver or plan communication interventions in ways that are responsive to and acceptable to parents.[4] The qualitative synthesis method, therefore, puts a spotlight on how people's experiences of health and health care in the context of their lives may lead to the design of better interventions, as well as to experimental studies which take more account of the diversity that exists in people's attitudes and decision‐making experiences.[5] In the case of this qualitative evidence synthesis by Ames and colleagues, the method pulled together a substantial body of research (35 data‐rich studies were sampled from 48 studies identified, with the high‐to‐moderate confidence in the evidence for 13 of the synthesized findings). The evidence from this review can inform the development of interventions, and the design of trials and their implementation. While waiting for such new trials or trial evidence on effects to emerge, decision‐makers can build their programs on the highly informative base developed by this review. This qualitative evidence synthesis, alongside other reviews, has informed development by the World Health Organization of its first guideline for using digital technologies for health systems strengthening,[1, 6] part of a comprehensive program of work to better understand and support implementation of such new technologies.

Ryan R ，Hill S 《Cochrane Database of Systematic Reviews》