The behavior of chemical warfare agents (CWAs) on urban materials, such as concrete, significantly impacts forensic and military responses to chemical incidents. This study examined the persistence and degradation mechanisms of sarin (GB), soman (GD), and sulfur mustard (HD) on three types of commonly used concrete with varying water-cement ratios. Over two months, we evaluated the effects of concrete composition, temperature, and fragment size on CWA behavior. Half-lives and activation energies for CWA dissipation were calculated under various conditions. Results showed that concrete properties and external temperature strongly influenced dissipation rates. G-series agents underwent rapid hydrolysis, forming methylphosphonates, while HD degradation involved elimination, nucleophilic substitution, and oxidation, producing several previously unreported byproducts. Smaller concrete fragments increased recovery values and accelerated degradation due to greater surface area exposure, and higher temperatures further enhanced dissipation rates, particularly for volatile agents. Differences in dissipation among concrete types were linked to their physical and chemical properties, notably water-cement ratios. This study highlights the challenges of detecting CWAs due to their rapid penetration and transformation in concrete and provides insights for improving sampling, identification, and decontamination strategies under realistic conditions.
- Publikační typ
- časopisecké články MeSH
Background/Objectives: Tacrine is a centrally active non-competitive reversible acetylcholinesterase inhibitor. It also exerts antagonising activity against N-methyl-D-aspartate receptors. Tacrine was approved for the treatment of Alzheimer's disease in 1993, but was withdrawn from clinical use in 2013 because of its hepatotoxicity and gastrointestinal side effects. Nevertheless, tacrine is currently facing a renewed wave of interest primarily due to several new tacrine-incorporated hybrids and derivates. There were two specific aims for this study: firstly, to explain the mechanisms of the adverse action of tacrine, as a distinctive example of a highly effective acetylcholinesterase inhibitor; and secondly to check whether luminal impedance planimetry is feasible for preclinical testing of possible side effects of compounds potentially toxic to the gastrointestinal tract. Methods: Six experimental pigs were used as the animal model in this study. Five major parameters were evaluated: luminal pressure (mmHg), estimated diameter (mm), cross-sectional area (mm2), distensibility (mm2/mmHg), and zone compliance (mm3/mmHg). All measurements were performed before and 360 min after intragastric administration of 200 mg tacrine (at the porcine tacrine Tmax). Results: This study consistently demonstrated an increase in luminal pressure (a directly measured indicator) for the particular balloon filling volumes used, and inversely a reciprocal decrease in the other parameters after tacrine administration. Conclusions: Endoscopic luminal impedance planimetry is a feasible method to evaluate functional response of the lower oesophageal sphincter to tacrine in experimental pigs. Tacrine did not compromise the function of the lower oesophageal sphincter either toward oesophageal spasms or, in contrast, decreased competence of the lower oesophageal sphincter.
- Publikační typ
- časopisecké články MeSH
We aimed to prepare novel dibenzo [a,d][7]annulen derivatives that act on N-methyl-d-aspartate (NMDA) receptors with potential neuroprotective effects. Our approach involved modifying the tropane moiety of MK-801, a potent open-channel blocker known for its psychomimetic side effects, by introducing a seven-membered ring with substituted base moieties specifically to alleviate these undesirable effects. Our in silico analyses showed that these derivatives should have high gastrointestinal absorption and cross the blood-brain barrier (BBB). Our pharmacokinetic studies in rats supported this conclusion and confirmed the ability of leading compounds 3l and 6f to penetrate the BBB. Electrophysiological experiments showed that all compounds exhibited different inhibitory activity towards the two major NMDA receptor subtypes, GluN1/GluN2A and GluN1/GluN2B. Of the selected compounds intentionally differing in the inhibitory efficacy, 6f showed high relative inhibition (∼90 % for GluN1/GluN2A), while 3l showed moderate inhibition (∼50 %). An in vivo toxicity study determined that compounds 3l and 6f were safe at 10 mg/kg doses with no adverse effects. Behavioral studies demonstrated that these compounds did not induce hyperlocomotion or impair prepulse inhibition of startle response in rats. Neuroprotective assays using a model of NMDA-induced hippocampal neurodegeneration showed that compound 3l at a concentration of 30 μM significantly reduced hippocampal damage in rats. These results suggest that these novel dibenzo [a,d][7]annulen derivatives are promising candidates for developing NMDA receptor-targeted therapies with minimal psychotomimetic side effects.
- MeSH
- dizocilpinmaleát * farmakologie MeSH
- hematoencefalická bariéra metabolismus účinky léků MeSH
- krysa rodu rattus MeSH
- lidé MeSH
- molekulární struktura MeSH
- neuroprotektivní látky * farmakologie chemie chemická syntéza MeSH
- potkani Sprague-Dawley MeSH
- receptory N-methyl-D-aspartátu * antagonisté a inhibitory metabolismus MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- vztahy mezi strukturou a aktivitou MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- lidé MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
A benzodiazepine, diazepam, has been the leading antidote for seizures caused by nerve agents, the most toxic chemical weapons of mass destruction, since the 1960s. However, its limitations have often brought questions about its usefulness. Extensive effort has been devoted into exploring alternatives, such as other benzodiazepines, anticholinergics, or glutamate antagonists. However, only few showed clear clinical benefit. The only two options to ultimately reach clinical milestones are Avizafone, a water-soluble prodrug of diazepam adopted by the French and UK armed forces, and intramuscular midazolam, adopted by the US Army. The recently FDA-approved new intramuscular application of midazolam brought several advantages, such as rapid onset of action, short duration with predictable pharmacokinetics, increased water solubility for aqueous injectable solutions, and prolonged storage stability. Herein, we discuss the pitfalls and prospects of using midazolam as a substitute in anticonvulsant therapy with a particular focus on military purposes in combat casualty care. We have also considered and discussed several other alternatives that are currently at the experimental level. Recent studies have shown the superiority of midazolam over other benzodiazepines in the medical management of poisoned casualties. While its use in emergency care is straightforward, the proper dose for soldiers under battlefield conditions is questionable due to its sedative effects.
- MeSH
- antikonvulziva * aplikace a dávkování terapeutické užití MeSH
- diazepam * aplikace a dávkování MeSH
- lidé MeSH
- midazolam * aplikace a dávkování MeSH
- nervová bojová látka * MeSH
- záchvaty * farmakoterapie chemicky indukované MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
N-methyl-D-aspartate receptors (NMDARs) play a significant role in developing several central nervous system (CNS) disorders. Currently, memantine, used for treating Alzheimer's disease, and ketamine, known for its anesthetic and antidepressant properties, are two clinically used NMDAR open-channel blockers. However, despite extensive research into NMDAR modulators, many have shown either harmful side effects or inadequate effectiveness. For instance, dizocilpine (MK-801) is recognized for its powerful psychomimetic effects due to its high-affinity and nearly irreversible inhibition of the GluN1/GluN2 NMDAR subtypes. Unlike ketamine, memantine and MK-801 also act through a unique, low-affinity "membrane-to-channel inhibition" (MCI). We aimed to develop an open-channel blocker based on MK-801 with distinct inhibitory characteristics from memantine and MK-801. Our novel compound, K2060, demonstrated effective voltage-dependent inhibition in the micromolar range at key NMDAR subtypes, GluN1/GluN2A and GluN1/GluN2B, even in the presence of Mg2+. K2060 showed reversible inhibitory dynamics and a partially trapping open-channel blocking mechanism with a significantly stronger MCI than memantine. Using hippocampal slices, 30 μM K2060 inhibited excitatory postsynaptic currents in CA1 hippocampal neurons by ∼51 %, outperforming 30 μM memantine (∼21 % inhibition). K2060 exhibited No Observed Adverse Effect Level (NOAEL) of 15 mg/kg upon intraperitoneal administration in mice. Administering K2060 at a 10 mg/kg dosage resulted in brain concentrations of approximately 2 μM, with peak concentrations (Tmax) achieved within 15 minutes. Finally, applying K2060 with trimedoxime and atropine in mice exposed to tabun improved treatment outcomes. These results underscore K2060's potential as a therapeutic agent for CNS disorders linked to NMDAR dysfunction.
- MeSH
- antagonisté excitačních aminokyselin farmakologie MeSH
- dizocilpinmaleát * farmakologie MeSH
- excitační postsynaptické potenciály účinky léků MeSH
- hipokampus účinky léků metabolismus MeSH
- lidé MeSH
- memantin farmakologie MeSH
- myši inbrední C57BL MeSH
- myši MeSH
- neurony účinky léků metabolismus MeSH
- receptory N-methyl-D-aspartátu * antagonisté a inhibitory metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The increasing threat of nuclear incidents and the widespread use of ionizing radiation (IR) in medical treatments underscore the urgent need for effective radiation countermeasures. Despite the availability of compounds such as amifostine, their clinical utility is significantly limited by adverse side effects and logistical challenges in administration. This study focuses on the synthesis and evaluation of novel piperazine derivatives as potential radioprotective agents, with the aim of overcoming the limitations associated with current countermeasures. We designed, synthesized, and evaluated a series of 1-(2-hydroxyethyl)piperazine derivatives. The compounds were assessed for cytotoxicity across a panel of human cell lines, and for their radioprotective effects in the MOLT-4 lymphoblastic leukemia cell line and in peripheral blood mononuclear cells (PBMCs) exposed to gamma radiation. The radioprotective efficacy was further quantified using the dicentric chromosome assay (DCA) to measure DNA damage mitigation. Among the synthesized derivatives, compound 6 demonstrated the most significant radioprotective effects in vitro, with minimal cytotoxicity across the tested cell lines. Compound 3 also showed notable efficacy, particularly in reducing dicentric chromosomes, thus indicating its potential to mitigate DNA damage from IR. Both compounds exhibited superior safety profiles and effectiveness compared to amifostine, suggesting their potential as more viable radioprotective agents. This study highlights the development of novel piperazine derivatives with promising radioprotective properties. Compound 6 emerged as the leading candidate, offering an optimal balance between efficacy and safety, with compound 3 also displaying significant potential. These findings support the further development and clinical evaluation of these compounds as safer, and more effective radiation countermeasures.
- Publikační typ
- časopisecké články MeSH
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.
- MeSH
- acetylcholinesterasa MeSH
- antidota farmakologie MeSH
- butyrylcholinesterasa MeSH
- cholinesterasové inhibitory toxicita MeSH
- fosfor MeSH
- krysa rodu rattus MeSH
- kyslík MeSH
- lidé MeSH
- oximy farmakologie MeSH
- pralidoximové sloučeniny * MeSH
- pyridinové sloučeniny farmakologie MeSH
- reaktivátory cholinesterasy * farmakologie MeSH
- taurin analogy a deriváty MeSH
- trimedoxim farmakologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Tacrine (THA), a long withdrawn drug, is still a popular scaffold used in medicinal chemistry, mainly for its good reactivity and multi-targeted effect. However, THA-associated hepatotoxicity is still an issue and must be considered in drug discovery based on the THA scaffold. Following our previously identified hit compound 7-phenoxytacrine (7-PhO-THA), we systematically explored the chemical space with 30 novel derivatives, with a focus on low hepatotoxicity, anticholinesterase action, and antagonism at the GluN1/GluN2B subtype of the NMDA receptor. Applying the down-selection process based on in vitro and in vivo pharmacokinetic data, two candidates, I-52 and II-52, selective GluN1/GluN2B inhibitors thanks to the interaction with the ifenprodil-binding site, have entered in vivo pharmacodynamic studies. Finally, compound I-52, showing only minor affinity to AChE, was identified as a lead candidate with favorable behavioral and neuroprotective effects using open-field and prepulse inhibition tests, along with scopolamine-based behavioral and NMDA-induced hippocampal lesion models. Our data show that compound I-52 exhibits low toxicity often associated with NMDA receptor ligands, and low hepatotoxicity, often related to THA-based compounds.
- MeSH
- acetylcholinesterasa metabolismus MeSH
- Alzheimerova nemoc * farmakoterapie MeSH
- cholinesterasové inhibitory chemie MeSH
- cholinesterasy MeSH
- lékové postižení jater * MeSH
- lidé MeSH
- neuroprotektivní látky * farmakologie terapeutické užití MeSH
- piperidiny * MeSH
- receptory N-methyl-D-aspartátu MeSH
- takrin chemie MeSH
- vazebná místa MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Organophosphorus compounds (OP) are a constant problem, both in the military and in the civilian field, not only in the form of acute poisoning but also for their long-lasting consequences. No antidote has been found that satisfactorily protects against the toxic effects of organophosphates. Likewise, there is no universal cure to avert damage after poisoning. The key mechanism of organophosphate toxicity is the inhibition of acetylcholinesterase. The overstimulation of nicotinic or muscarinic receptors by accumulated acetylcholine on a synaptic cleft leads to activation of the glutamatergic system and the development of seizures. Further consequences include generation of reactive oxygen species (ROS), neuroinflammation, and the formation of various other neuropathologists. In this review, we present neuroprotection strategies which can slow down the secondary nerve cell damage and alleviate neurological and neuropsychiatric disturbance. In our opinion, there is no unequivocal approach to ensure neuroprotection, however, sooner the neurotoxicity pathway is targeted, the better the results which can be expected. It seems crucial to target the key propagation pathways, i.e., to block cholinergic and, foremostly, glutamatergic cascades. Currently, the privileged approach oriented to stimulating GABAAR by benzodiazepines is of limited efficacy, so that antagonizing the hyperactivity of the glutamatergic system could provide an even more efficacious approach for terminating OP-induced seizures and protecting the brain from permanent damage. Encouraging results have been reported for tezampanel, an antagonist of GluK1 kainate and AMPA receptors, especially in combination with caramiphen, an anticholinergic and anti-glutamatergic agent. On the other hand, targeting ROS by antioxidants cannot or already developed neuroinflammation does not seem to be very productive as other processes are also involved.
- MeSH
- acetylcholinesterasa metabolismus MeSH
- cholinesterasové inhibitory toxicita MeSH
- lidé MeSH
- neurotoxické syndromy * etiologie prevence a kontrola MeSH
- neurozánětlivé nemoci MeSH
- organofosfáty MeSH
- otrava organofosfáty * farmakoterapie prevence a kontrola MeSH
- reaktivní formy kyslíku MeSH
- záchvaty MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
