Antidotes against organophosphates often possess physicochemical properties that mitigate their passage across the blood-brain barrier. Cucurbit[7]urils may be successfully used as a drug delivery system for bisquaternary oximes and improve central nervous system targeting. The main aim of these studies was to elucidate the relationship between cucurbit[7]uril, oxime K027, atropine, and paraoxon to define potential risks or advantages of this delivery system in a complex in vivo system. For this reason, in silico (molecular docking combined with umbrella sampling simulation) and in vivo (UHPLC-pharmacokinetics, toxicokinetics; acetylcholinesterase reactivation and functional observatory battery) methods were used. Based on our results, cucurbit[7]urils affect multiple factors in organophosphates poisoning and its therapy by (i) scavenging paraoxon and preventing free fraction of this toxin from entering the brain, (ii) enhancing the availability of atropine in the central nervous system and by (iii) increasing oxime passage into the brain. In conclusion, using cucurbit[7]urils with oximes might positively impact the overall treatment effectiveness and the benefits can outweigh the potential risks.
- MeSH
- atropin chemie MeSH
- hematoencefalická bariéra MeSH
- imidazoly chemie MeSH
- myši MeSH
- oximy chemie MeSH
- paraoxon chemie toxicita MeSH
- počítačová simulace MeSH
- přemostěné cyklické sloučeniny chemie MeSH
- pyridinové sloučeniny chemie MeSH
- reaktivátory cholinesterázy chemie toxicita MeSH
- simulace molekulového dockingu MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
AIMS: Organophosphates (OPCs), useful agents as pesticides, also represent a serious health hazard. Standard therapy with atropine and established oxime-type enzyme reactivators is unsatisfactory. Experimental data indicate that superior therapeutic results can be obtained when reversible cholinesterase inhibitors are administered before OPC exposure. Comparing the protective efficacy of five such cholinesterase inhibitors (physostigmine, pyridostigmine, ranitidine, tacrine, or K-27), we observed best protection for the experimental oxime K-27. The present study was undertaken in order to determine if additional administration of K-27 immediately after OPC (paraoxon) exposure can improve the outcome. METHODS: Therapeutic efficacy was assessed in rats by determining the relative risk of death (RR) by Cox survival analysis over a period of 48 h. Animals that received only pretreatment and paraoxon were compared with those that had received pretreatment and paraoxon followed by K-27 immediately after paraoxon exposure. RESULTS: Best protection from paraoxon-induced mortality was observed after pretreatment with physostigmine (RR = 0.30) and K-27 (RR = 0.34). Both substances were significantly more efficacious than tacrine (RR = 0.67), ranitidine (RR = 0.72), and pyridostigmine (RR = 0.76), which were less efficacious but still significantly reduced the RR compared to the no-treatment group (paraoxon only). Additional administration of K-27 immediately after paraoxon exposure (posttreatment) did not further reduce mortality. Statistical analysis between pretreatment before paraoxon exposure alone and pretreatment plus K-27 posttreatment did not show any significant difference for any of the pretreatment regimens. CONCLUSIONS: Best outcome is achieved if physostigmine or K-27 are administered prophylactically before exposure to sublethal paraoxon dosages. Therapeutic outcome is not further improved by additional oxime therapy immediately thereafter.
- MeSH
- analýza přežití MeSH
- cholinesterasové inhibitory aplikace a dávkování toxicita MeSH
- fysostigmin aplikace a dávkování chemie MeSH
- krysa rodu rattus MeSH
- organofosfáty toxicita MeSH
- oximy aplikace a dávkování chemie MeSH
- paraoxon chemie toxicita MeSH
- postexpoziční profylaxe MeSH
- potkani Wistar MeSH
- preexpoziční profylaxe MeSH
- proporcionální rizikové modely MeSH
- pyridostigmin-bromid aplikace a dávkování chemie MeSH
- ranitidin chemie farmakologie MeSH
- reaktivátory cholinesterázy farmakologie MeSH
- takrin aplikace a dávkování chemie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Organophosphorus compounds (OP) are chemicals widely used as pesticides in different applications such as agriculture and public health (vector control), and some of the highly toxic forms have been used as chemical weapons. After application of OPs in an environment, they persist for a period, suffering a degradation process where the biotic factors are considered the most relevant forms. However, to date, the biodegradation of OP compounds is not well understood. There are a plenty of structure-based biodegradation estimation methods, but none of them consider enzymatic interaction in predicting and better comprehending the differences in the fate of OPs in the environment. It is well known that enzymatic processes are the most relevant processes in biodegradation, and that hydrolysis is the main pathway in the natural elimination of OPs in soil samples. Due to this, we carried out theoretical studies in order to investigate the interactions of these OPs with a chosen enzyme-the phosphotriesterase. This one is characteristic of some soils' microorganisms, and has been identified as a key player in many biodegradation processes, thanks to its capability for fast hydrolyzing of different OPs. In parallel, we conducted an experiment using native soil in two conditions, sterilized and not sterilized, spiked with specific amounts of two OPs with similar structure-paraoxon-ethyl (PXN) and O-(4-nitrophenyl) O-ethyl methylphosphonate (NEMP). The amount of OP present in the samples and the appearance of characteristic hydrolysis products were periodically monitored for 40 days using analytical techniques. Moreover, the number of microorganisms present was obtained with plate cell count. Our theoretical results were similar to what was achieved in experimental analysis. Parameters calculated by enzymatic hydrolysis were better for PXN than for NEMP. In soil, PXN suffered a faster hydrolysis than NEMP, and the cell count for PXN was higher than for NEMP, highlighting the higher microbiological toxicity of the latter. All these results pointed out that theoretical study can offer a better comprehension of the possible mechanisms involved in real biodegradation processes, showing potential in exploring how biodegradation of OPs relates with enzymatic interactions.
- MeSH
- biodegradace * MeSH
- chemická válka MeSH
- hydrolýza MeSH
- insekticidy chemie metabolismus MeSH
- lidé MeSH
- organofosforové sloučeniny chemie metabolismus MeSH
- paraoxon analogy a deriváty chemie MeSH
- pesticidy chemie toxicita MeSH
- půda chemie MeSH
- pyrrolidiny chemie MeSH
- veřejné zdravotnictví MeSH
- zemědělství MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Organophosphates, useful agents as pesticides, also represent a serious danger due to their high acute toxicity. There is indication that oximes, when administered before organophosphate exposure, can protect from these toxic effects. We have tested at equitoxic dosage (25% of LD01 ) the prophylactic efficacy of five experimental (K-48, K-53, K-74, K-75, K-203) and two established oximes (pralidoxime and obidoxime) to protect from mortality induced by the organophosphate paraoxon. Mortalities were quantified by Cox analysis and compared with those observed after pretreatment with a strong acetylcholinesterase inhibitor (10-methylacridine) and after the FDA-approved pretreatment compound pyridostigmine. All nine tested substances statistically significantly reduced paraoxon-induced mortality. Best protection was conferred by the experimental oxime K-48, reducing the relative risk of death (RR) to 0.10, which was statistically significantly superior to pyridostigmine (RR = 0.31). The other oximes reduced the RR to 0.13 (obidoxime), 0.20 (K-203), 0.21 (K-74), 0.24 (K-75) and 0.26 (pralidoxime), which were significantly more efficacious than 10-methylacridine (RR = 0.65). These data support the hypothesis that protective efficacy is not primarily due to cholinesterase inhibition and indicate that the tested experimental oximes may be considered promising alternatives to the established pretreatment compound pyridostigmine.
- MeSH
- analýza přežití MeSH
- LD50 MeSH
- obidoxim chlorid aplikace a dávkování farmakologie MeSH
- ochranné látky aplikace a dávkování farmakologie MeSH
- paraoxon chemie toxicita MeSH
- potkani Wistar MeSH
- pralidoximové sloučeniny aplikace a dávkování farmakologie MeSH
- proporcionální rizikové modely MeSH
- reaktivátory cholinesterázy aplikace a dávkování farmakologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The present work aimed to compare the small, neutral and monoaromatic oxime, isatin-3-oxime (isatin-O), to the commercial ones, pralidoxime (2-PAM) and obidoxime, in a search for a new potential reactivator for acetylcholinesterase (AChE) inhibited by the pesticide paraoxon (AChE/POX) as well as a novel potential scaffold for further synthetic modifications. The multicriteria decision methods (MCDM) allowed the identification of the best docking poses of those molecules inside AChE/POX for further molecular dynamic (MD) studies, while Ellman's modified method enabled in vitro inhibition and reactivation assays. In corroboration with the theoretical studies, our experimental results showed that isatin-O have a reactivation potential capable of overcoming 2-PAM at the initial moments of the assay. Despite not achieving better results than obidoxime, this molecule is promising for being an active neutral oxime with capacity of crossing the blood⁻brain barrier (BBB), to reactivate AChE/POX inside the central and peripheral nervous systems. Moreover, the fact that isatin-O can also act as anticonvulsant makes this molecule a possible multipotent reactivator. Besides, the MCDM method showed to be an accurate method for the selection of the best docking poses generated in the docking studies.
- MeSH
- cholinesterasové inhibitory farmakologie MeSH
- erytrocyty účinky léků enzymologie MeSH
- molekulární modely * MeSH
- molekulární struktura MeSH
- oximy chemie farmakologie MeSH
- paraoxon chemie farmakologie MeSH
- reaktivátory cholinesterázy chemie farmakologie MeSH
- simulace molekulární dynamiky MeSH
- simulace molekulového dockingu MeSH
- Publikační typ
- časopisecké články MeSH
The aim of this study was to determine optimal conditions for in vitro skin decontamination using water and detergents as decontamination agents and to test the cleansing efficiency of selected detergents. Experiments were performed using a peristaltic pump for showering of pig skin in modified static diffusion cells. Several conditions were tested including different flow rates (from 5 to 33 ml s-1), quantity of rinsing fluid (from 40 to 400 ml) and concentration of detergents (2; 5; 10%). Further, several types of detergents/commercial decontamination agents were evaluated under the selected conditions to find the most effective means of decontamination. The amount of paraoxon removed from the skin surface following wet-type decontamination was detected in the rinsing fluid spectrophotometrically after hydrolysis of paraoxon - a model contaminant. The efficacy of rinsing by water/Spolapon AES 253 increased with flow rate up to 25 ml s-1 and a rinsing volume of 200 ml. Lutensol AT 25 achieved maximum efficacy at the lowest tested concentration (2%). A flow rate of 16 ml s-1, rinsing volume of 100 ml (values from the middle part of the sigmoid curve) and 5% concentration of decontaminant solution were used for further evaluation of detergents as cleansing agents under the selected conditions. Cetylpyridinium bromide (cationic surfactant), carbethopendecinii bromidum (cationic surfactant) and polyoxyethylene-10-tridecyl ether (non-ionic surfactant), SDS (anionic surfactant), althosan MB (cationic surfactant), sodium dodecylbenzene sulphonate (anionic surfactant), neodekont (mixture), tergitol NPX (non-ionic surfactant), Korynt P (non-ionic surfactant) were found to be the most effective. These decontaminants were able to wash away more than 92% of paraoxon from the contaminated skin.
Organophosphate (OP) poisoning is a major global health issue; while compounds from this group have been used intensively over the last century, an effective antidote is still lacking. Oxime-type acetylcholinesterase (AChE) reactivators are used to reactivate the OP inhibited AChE. Pralidoxime is the only US Food and Drug Administration approved oxime for therapeutic use but its efficacy has been disappointing. Two novel oximes (K378 and K727) were investigated in silico and in vitro and compared with an experimental oxime (kamiloxime; K-27) and pralidoxime. In silico the molecular interactions between AChE and oximes were examined and binding energies were assessed. LogP (predicted log of the octanol/water partition coefficient) was estimated. In vitro the intrinsic ability of the oximes to inhibit AChE (IC50) and their reactivation potency (R50) when used in paraoxon inhibited human RBC-AChE was determined. Molecular docking revealed that K378 and K727 bind to the peripheral site(s) with high binding energies in contrast to the central binding of K-27 and pralidoxime. LogP values indicating that the novel compounds are significantly less hydrophilic than K-27 or pralidoxime. IC50 of K378 and K727 were comparable (0.9 and 1 µM, respectively) but orders of magnitude lower than comparators. R50 values revealed their inability to reactivate paraoxon inhibited AChE. It is concluded that the novel oximes K378 and K727 are unlikely to be clinically useful. The in silico and in vitro studies described allow avoidance of unnecessary in vivo animal work and contribute to the reduction of laboratory animal use.
- MeSH
- acetylcholinesterasa krev chemie MeSH
- antidota chemie metabolismus farmakologie MeSH
- cholinesterasové inhibitory chemie metabolismus toxicita MeSH
- GPI-vázané proteiny antagonisté a inhibitory krev chemie MeSH
- konformace proteinů MeSH
- lidé MeSH
- otrava organofosfáty krev farmakoterapie enzymologie MeSH
- oximy chemie metabolismus farmakologie MeSH
- paraoxon analogy a deriváty chemie metabolismus toxicita MeSH
- pralidoximové sloučeniny chemie metabolismus farmakologie MeSH
- pyridinové sloučeniny chemie metabolismus farmakologie MeSH
- reaktivátory cholinesterázy chemie metabolismus farmakologie MeSH
- simulace molekulového dockingu * MeSH
- vazba proteinů MeSH
- vazebná místa MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
Nerve agents and oxon forms of organophosphorus pesticides act as strong irreversible inhibitors of two cholinesterases in the human body: acetylcholinesterase (AChE; EC 3.1.1.7) and butyrylcholinesterase (BChE; EC 3.1.1.8), and are therefore highly toxic compounds. For the recovery of inhibited AChE, antidotes from the group of pyridinium or bispyridinium aldoxime reactivators (pralidoxime, obidoxime, HI-6) are used in combination with anticholinergics and anticonvulsives. Therapeutic efficacy of reactivators (called “oximes”) depends on their chemical structure and also the type of organophosphorus inhibitor. Three novel oximes (K131, K142, K153) with an oxime group in position four of the pyridinium ring were designed and then tested for their potency to reactivate human (Homo sapiens sapiens) AChE (HssACHE) and BChE (HssBChE) inhibited by the pesticide paraoxon (diethyl 4-nitrophenyl phosphate). According to the obtained results, none of the prepared oximes were able to satisfactorily reactivate paraoxon-inhibited cholinesterases. On the contrary, extraordinary activity of obidoxime in the case of paraoxon-inhibited HssAChE reactivation was confirmed. Additional docking studies pointed to possible explanations for these results.
- MeSH
- acetylcholinesterasa chemie MeSH
- antidota chemická syntéza farmakologie MeSH
- butyrylcholinesterasa chemie MeSH
- cholinesterasové inhibitory chemie MeSH
- enzymatické testy MeSH
- erytrocyty účinky léků enzymologie MeSH
- insekticidy antagonisté a inhibitory chemie toxicita MeSH
- interakční proteinové domény a motivy MeSH
- lidé MeSH
- obidoxim chlorid chemie farmakologie MeSH
- oximy chemická syntéza farmakologie MeSH
- paraoxon antagonisté a inhibitory chemie toxicita MeSH
- reaktivátory cholinesterázy chemická syntéza farmakologie MeSH
- sekundární struktura proteinů MeSH
- simulace molekulového dockingu MeSH
- termodynamika MeSH
- vazba proteinů MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Misuse of various chemicals, such as chemical warfare agents, industrial chemicals or pesticides during warfare or terrorists attacks requires adequate protection. Thus, development and evaluation of novel decontamination dispositives and techniques are needed. In this study, in vitro permeation and decontamination of a potentially hazardous compound paraoxon, an active metabolite of organophosphorus pesticide parathion, was investigated. Skin permeation and decontamination experiments were carried out in modified Franz diffusion cells. Pig skin was used as a human skin model. Commercially produced detergent-based washing solutions FloraFree(™) and ArgosTM were used as decontamination means. The experiments were done under "warm", "cold", "dry" and "wet" skin conditions in order to determine an effect of various physical conditions on skin permeation of paraoxon and on a subsequent decontamination process. There was no significant difference in skin permeation of paraoxon under warm, cold and dry conditions, whereas wet conditions provided significantly higher permeation rates. In the selected conditions, decontamination treatments performed 1 h after a skin exposure did not decrease the agent volume that permeated through the skin. An exception were wet skin conditions with non-significant decontamination efficacy 18 and 28% for the FloraFree(™) and Argos(™) treatment, respectively. In contrast, the skin permeation of paraoxon under warm, cold and dry conditions increased up to 60-290% following decontamination compared to non-decontaminated controls. This has previously been described as a skin wash-in effect.
- MeSH
- časové faktory MeSH
- chemické jevy MeSH
- dekontaminace * metody MeSH
- detergenty farmakologie MeSH
- difuzní komory kultivační MeSH
- kožní absorpce účinky léků fyziologie MeSH
- kůže chemie účinky léků metabolismus MeSH
- lidé MeSH
- paraoxon chemie farmakokinetika MeSH
- permeabilita účinky léků MeSH
- pesticidy chemie farmakokinetika MeSH
- Sus scrofa MeSH
- techniky in vitro MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Klíčová slova
- reaktivátor, nervově paralytická látka, organofosfátový insekticid,
- MeSH
- acetylcholinesterasa MeSH
- Electrophorus MeSH
- financování organizované MeSH
- indoly diagnostické užití chemie MeSH
- insekticidy škodlivé účinky toxicita MeSH
- lidé MeSH
- organofosfáty chemie škodlivé účinky MeSH
- oximy terapeutické užití MeSH
- paraoxon chemie MeSH
- reaktivátory cholinesterázy terapeutické užití MeSH
- referenční standardy MeSH
- sarin chemie MeSH
- spektrofotometrie metody využití MeSH
- Check Tag
- lidé MeSH
