Oxime-based molecules are used for the treatment of patients to reactivate acetylcholinesterase (AChE) function after organophosphate intoxication. However, their efficacy is limited by low penetration through the blood-brain barrier and fast elimination. In this work, the cucurbit[7]uril (CB[7]) carrier was used for the encapsulation of the clinical agent asoxime to enhance brain bioavailability and the treatment window. We present a pharmacokinetic study of asoxime and the asoxime-CB[7] complex in an in vivo mouse model. Ultrahigh-performance liquid chromatography with electrospray ionization-mass spectrometry detection was developed to determine asoxime and CB[7] in biological fluids and tissues after thorough optimization of chromatographic conditions. The dihydroxypropane-silica stationary phase using hydrophilic interaction liquid chromatography conditions provided the best chromatographic performance. The final method was validated and applied for the pharmacokinetic study of mouse plasma, urine, bile, liver, kidney, and brain samples at different times after administration of asoxime and the asoxime-CB[7] complex. The results showed a greater than 3-fold increase in the area under the curve (AUC) in the brain for asoxime administered as a complex with CB[7] relative to that for the administration of asoxime alone. The effectiveness of the treatment strategy was evaluated using a reactivation study and a functional observatory battery. Protection of brain AChE activity is crucial for saving human lives or reducing the consequences of poisoning. The asoxime administered as a complex increased the brain activity by approximately 30% compared to that with atropine alone. CB[7] coadministration improved the AChE activity by 11%, which agrees with the higher asoxime AUC assessed in the pharmacokinetic study.

• MeSH
• acetylcholinesterasa metabolismus   MeSH
• cholinesterasové inhibitory aplikace a dávkování   toxicita   MeSH
• enzymatické testy MeSH
• hematoencefalická bariéra metabolismus   MeSH
• hmotnostní spektrometrie MeSH
• hydrofobní a hydrofilní interakce MeSH
• imidazoly chemie   MeSH
• lidé MeSH
• modely nemocí na zvířatech MeSH
• myši MeSH
• nosiče léků chemie   MeSH
• otrava organofosfáty farmakoterapie   MeSH
• oximy aplikace a dávkování   farmakokinetika   MeSH
• plocha pod křivkou MeSH
• přemostěné cyklické sloučeniny chemie   MeSH
• pyridinové sloučeniny aplikace a dávkování   farmakokinetika   MeSH
• reaktivátory cholinesterasy aplikace a dávkování   farmakokinetika   MeSH
• sarin aplikace a dávkování   toxicita   MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Therapeutic efficacy of antidotal treatment of acute poisoning by nerve agents is generally assessed by the evaluation of LD50 values of nerve agents over 24 h following poisoning without or with a single administration of antidotal treatment. In this study, LD50 values of four nerve agents (sarin, soman, tabun and cyclosarin) for non-treated and treated poisoning were evaluated in mice for two experimental end points - 6 h and 24 h. While the efficacy of atropine or oxime-based antidotal treatment was the same regardless of the experimental end point, the therapeutic efficacy of all three newly developed bispyridinium non-oxime compounds (MB408, MB442, and MB444) was mostly slightly higher at the 6 h end point compared to the 24 h end point, although the therapeutic efficacy of MB compounds was not superior to oxime-based antidotal treatment. These results contrast with a study in guinea-pigs using a structurally-related compound, MB327, which showed a striking increase in protection at 6 h compared to 24 h. It is suggested that the disparity may be due to pharmacokinetic differences between the two animal species.

• MeSH
• antidota farmakologie   MeSH
• časové faktory MeSH
• chemické bojové látky toxicita   MeSH
• LD50 MeSH
• myši MeSH
• nikotinoví antagonisté farmakologie   MeSH
• organofosfáty toxicita   MeSH
• organofosforové sloučeniny toxicita   MeSH
• otrava organofosfáty farmakoterapie   etiologie   MeSH
• oximy farmakologie   MeSH
• pyridinové sloučeniny farmakologie   MeSH
• reaktivátory cholinesterasy farmakologie   MeSH
• sarin toxicita   MeSH
• soman toxicita   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH

The potency of three nerve agents (sarin, soman, tabun) to induce oxidative damage of DNA in lymphocytes, liver and brain during lethal or sublethal poisoning was investigated. The single strand breaks or oxidative base DNA damage was evaluated with the help of Comet assay and a specific enzyme able to detect oxidative bases of DNA (endonuclease III). While sarin and soman administered at sublethal doses corresponding to 50% of their LD50 values were not able to induce oxidative damage of DNA, their lethal dose (LD50) induced the significant increase of the number of oxidative bases in DNA of hepatocytes. In addition, tabun administered at lethal dose (LD50) induced significant increase of the number of single strand breaks and oxidative bases of DNA in glial cells isolated from pontomedullar brain region. Thus, some nerve agents were able to induce oxidative damage in the peripheral as well as central compartment but only in the case of severe poisoning caused by lethal doses of nerve agents. This non-cholinergic effect of nerve agents has probably consequences with nerve agents-induced hypoxic status during acute cholinergic crisis and it can contribute to their long-term toxic effects.

• MeSH
• DNA * chemie   metabolismus   MeSH
• lidé MeSH
• organofosfáty toxicita   MeSH
• oxidační stres MeSH
• sarin toxicita   MeSH
• soman toxicita   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH

BACKGROUND: In the last decade, the concept of uncharged reactivators potentially able to penetrate the CNS has been introduced as an alternative to the classic charged oxime reactivators. However, this concept brings with it several associated drawbacks such as higher lipophilicity, difficulty in administration, lower affinity to cholinesterases, and higher toxicity risk. OBJECTIVE: In this study, we compare data obtained for a set of five classic charged reactivators and a set of three recently published uncharged oximes supplemented by two novel ones. METHODS: This time, we used only in silico prediction and in vitro approaches. RESULTS: Our data showed that tested uncharged oximes have low affinity for cholinesterases, do not possess high reactivation potency, and certainly represent a greater toxicity risk due to higher lipophilicity. We assume that balanced physicochemical properties will be required for the successful treatment of OP poisoning. Nevertheless, the compound meeting such criteria and pinpointed in silico (K1280) failed in this particular case. CONCLUSION: From the presented data, it seems that the concept of uncharged reactivators will have to be modified, at least to improve the bioavailability and to satisfy requirements for in vivo administration.

• MeSH
• antidota chemická syntéza   farmakologie   toxicita   MeSH
• butyrylcholinesterasa metabolismus   MeSH
• cholinesterasové inhibitory chemická syntéza   farmakologie   toxicita   MeSH
• hematoencefalická bariéra účinky léků   MeSH
• krysa rodu rattus MeSH
• myši MeSH
• organofosfáty toxicita   MeSH
• otrava organofosfáty farmakoterapie   MeSH
• oximy chemická syntéza   farmakologie   toxicita   MeSH
• paraoxon toxicita   MeSH
• počítačová simulace MeSH
• reaktivátory cholinesterasy chemická syntéza   farmakologie   toxicita   MeSH
• sarin toxicita   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: The method of continual determination of the rat blood cholinesterase activity was developed to study the changes of the blood cholinesterases following different intervetions. AIMS: The aim of this study is registration of cholinesterase activity in the rat blood and its changes to demonstrate detoxification capacity of rats to inactivate sarin or VX in vivo. METHODS: The groups of female rats were premedicated (ketamine and xylazine) and cannulated to a. femoralis. Continual blood sampling (0.02 ml/min) and monitoring of the circulating blood cholinesterase activity were performed. Normal activity was monitored 1-2 min and then the nerve agent was administered i.m. (2×LD50). Using different time intervals of the leg compression and relaxation following the agent injection, cholinesterase activity was monitored and according to the inhibition obtained, detoxification capacity was assessed. RESULTS: Administration of sarin to the leg, then 1 and 5 min compression and 20 min later relaxation showed that further inhibition in the blood was not observed. On the other hand, VX was able to inhibit blood cholinesterases after this intervention. CONCLUSIONS: The results demonstrated that sarin can be naturally detoxified on the contrary to VX. Described method can be used as model for other studies dealing with changes of cholinesterases in the blood following different factors.

• MeSH
• cholinesterasové inhibitory farmakokinetika   toxicita   MeSH
• cholinesterasy metabolismus   MeSH
• krysa rodu rattus MeSH
• metabolická inaktivace MeSH
• organothiofosforové sloučeniny farmakokinetika   toxicita   MeSH
• otrava organofosfáty metabolismus   MeSH
• potkani Wistar MeSH
• sarin farmakokinetika   toxicita   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The ability of two novel bispyridinium oximes K727 and K733 and currently available oximes (HI-6, obidoxime) to reactivate sarin-inhibited acetylcholinesterase and to reduce acute toxicity of sarin was evaluated. To investigate the reactivating efficacy of the oximes, the rats were administered intramuscularly with atropine and oximes in equitoxic doses corresponding to 5% of their LD50 values at 1 min after the intramuscular administration of sarin at a dose of 24 µg/kg (LD50). The activity of acetylcholinesterase was measured at 60 min after sarin poisoning. The LD50 value of sarin in non-treated and treated mice was assessed using probit-logarithmical analysis of death occurring within 24 h after intramuscular administration of sarin at five different doses. In vivo determined percentage of reactivation of sarin-inhibited rat blood, diaphragm and brain acetylcholinesterase showed that the potency of both novel oximes K727 and K733 to reactivate sarin-inhibited acetylcholinesterase roughly corresponds to the reactivating efficacy of obidoxime. On the other hand, the oxime HI-6 was found to be the most efficient reactivator of sarin-inhibited acetylcholinesterase. While the oxime HI-6 was able to reduce the acute toxicity of sarin >3 times, both novel oximes and obidoxime decreased the acute toxicity of sarin <2 times. Based on the results, we can conclude that the reactivating and therapeutic efficacy of both novel oximes K727 and K733 is significantly lower compared to the oxime HI-6 and, therefore, they are not suitable for the replacement of the oxime HI-6 for the antidotal treatment of acute sarin poisoning.

• MeSH
• acetylcholinesterasa krev   chemie   metabolismus   MeSH
• antagonisté muskarinových receptorů terapeutické užití   MeSH
• antidota terapeutické užití   MeSH
• atropin terapeutické užití   MeSH
• bránice účinky léků   enzymologie   MeSH
• cholinesterasové inhibitory aplikace a dávkování   chemie   toxicita   MeSH
• kombinovaná farmakoterapie MeSH
• mozek účinky léků   enzymologie   MeSH
• myši MeSH
• neurony účinky léků   enzymologie   MeSH
• neurotoxické syndromy krev   farmakoterapie   etiologie   metabolismus   MeSH
• obidoxim chlorid terapeutické užití   MeSH
• outbrední kmeny zvířat MeSH
• oximy terapeutické užití   MeSH
• potkani Wistar MeSH
• proteiny nervové tkáně agonisté   antagonisté a inhibitory   metabolismus   MeSH
• pyridinové sloučeniny terapeutické užití   MeSH
• reaktivátory cholinesterasy terapeutické užití   MeSH
• sarin aplikace a dávkování   antagonisté a inhibitory   toxicita   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

x

• Klíčová slova
• K378, K458, HI-6,
• MeSH
• antidota aplikace a dávkování   MeSH
• atropin aplikace a dávkování   MeSH
• chemické bojové látky otrava   MeSH
• cholinesterasové inhibitory terapeutické užití   MeSH
• kombinovaná farmakoterapie MeSH
• krysa rodu rattus MeSH
• LD50 MeSH
• myši MeSH
• neuroprotektivní látky aplikace a dávkování   MeSH
• obidoxim chlorid aplikace a dávkování   MeSH
• oximy * aplikace a dávkování   chemie   MeSH
• potkani Wistar MeSH
• pyridinové sloučeniny aplikace a dávkování   MeSH
• reaktivátory cholinesterasy aplikace a dávkování   MeSH
• sarin * otrava   toxicita   MeSH
• statistika jako téma MeSH
• testy akutní toxicity * statistika a číselné údaje   MeSH
• výsledek terapie MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH
• srovnávací studie MeSH

The potency of the oxime HI-6 and two combinations of oximes (HI-6 + trimedoxime, HI-6 + K203) to reduce sarin-induced acute neurotoxic signs and symptoms was evaluated in this study. Sarin-induced neurotoxicity and the neuroprotective effects of atropine alone or in combination with HI-6 alone and HI-6 combined with trimedoxime or K203 in rats poisoned with sarin at a sublethal dose (108 μg/kg i.m.; 90% of LD(50) value) were monitored by a functional observatory battery (FOB) 24 h following sarin administration. The results indicate that both mixtures of oximes combined with atropine were able to survive sarin-poisoned rats 24 h following sarin administration while two non-treated sarin-poisoned rats and one sarin-poisoned rat treated with atropine alone or with atropine in combination with the oxime HI-6 died within 24 h following sarin poisoning. All types of antidotal treatment were able to decrease sarin-induced neurotoxic signs and symptoms but not completely. While atropine alone and atropine in combination with the oxime HI-6 were able to eliminate some sarin-induced neurotoxic signs and symptoms, the neuroprotective efficacy of both combinations of oximes with atropine was slightly higher. Thus, both tested combinations of oximes in combination with atropine bring a small benefit for the neuroprotective efficacy of antidotal treatment of acute sarin poisonings.

• MeSH
• antidota aplikace a dávkování   terapeutické užití   MeSH
• atropin chemie   MeSH
• chemické bojové látky otrava   toxicita   MeSH
• cholinesterasové inhibitory otrava   toxicita   MeSH
• kombinovaná farmakoterapie MeSH
• krysa rodu rattus MeSH
• molekulární struktura MeSH
• neuroprotektivní látky terapeutické užití   MeSH
• oximy aplikace a dávkování   chemie   terapeutické užití   MeSH
• potkani Wistar MeSH
• pyridinové sloučeniny aplikace a dávkování   chemie   terapeutické užití   MeSH
• reaktivátory cholinesterasy aplikace a dávkování   terapeutické užití   MeSH
• sarin otrava   toxicita   MeSH
• trimedoxim aplikace a dávkování   chemie   terapeutické užití   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The neuroprotective effects of a newly developed oxime K203 and currently available oximes (obidoxime, HI-6) in combination with atropine in rats poisoned with sarin were studied. The sarin-induced neurotoxicity was monitored using a functional observatory battery at 2 hr after sarin challenge. The results indicate that the potency of a novel bispyridinium oxime K203 to counteract sarin-induced neurotoxicity is relatively low and roughly corresponds to the neuroprotective efficacy of obidoxime. Among tested oximes, the oxime HI-6 seems to be significanlty more efficacious to counteract acute neurotoxicity of sarin than commonly used obidoxime and a newly developed oxime K203. Thus, the oxime K203 does not provide any beneficial effect for the antidotal treatment of acute poisoning with sarin in comparison with the oxime HI-6 that should be considered to be the best oxime for antidotal treatment of acute sarin poisonings.

• MeSH
• antagonisté muskarinových receptorů terapeutické užití   MeSH
• antidota škodlivé účinky   terapeutické užití   MeSH
• atropin terapeutické užití   MeSH
• autonomní nervový systém účinky léků   patofyziologie   MeSH
• chemické bojové látky chemie   toxicita   MeSH
• cholinesterasové inhibitory chemie   toxicita   MeSH
• kombinovaná farmakoterapie MeSH
• krysa rodu rattus MeSH
• LD50 MeSH
• neurony účinky léků   MeSH
• neurotoxické syndromy farmakoterapie   patofyziologie   MeSH
• obidoxim chlorid škodlivé účinky   terapeutické užití   MeSH
• oximy škodlivé účinky   terapeutické užití   MeSH
• potkani Wistar MeSH
• psychomotorický výkon účinky léků   MeSH
• pyridinové sloučeniny škodlivé účinky   terapeutické užití   MeSH
• reaktivátory cholinesterasy škodlivé účinky   terapeutické užití   MeSH
• sarin antagonisté a inhibitory   toxicita   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Geografické názvy
• Česká republika MeSH

Sarin is a potent inhibitor of acetylcholinesterase (AChE). It is known as an agent of chemical warfare and is one of a number of nerve agents misused for chemical terrorism, e.g. on the Tokyo subway attacks. Though effect of sarin on the cholinergic system is well-known, long-term adverse effects and the role of oxidative stress in sarin toxicity remain unknown. The experiment reported here was carried out on laboratory Wistar rats intramuscularly exposed to 0.5–50% of sarin LD50 for one hour. A complex biochemical examination of plasma samples and an assessment of oxidative stress in the liver, kidney, spleen, cerebellum and frontal lobe were performed after euthanasia of the animals. By means of these biochemical markers, we were able to observe the induction of hyperglycaemia in a dose-dependent manner. Other biochemical markers such as transaminases were influenced in a non-standard manner as sarin probably acted as an inhibitor of these markers. Oxidative stress markers and an assessment of AChE activity showed an unequal impact of sarin on different tissues. Significant inhibition of AChE was found in the cerebellum and frontal lobe. Besides this, alterations in reduced glutathione, ferric reducing antioxidant power (FRAP) and thiobarbituric acid reactive substances (TBARS) were proven. In particular, an accumulation occurred of reduced glutathione in the frontal lobe, whereas depletion of FRAP was found in the kidney and spleen, and a strong increase in TBARS occurred in the spleen in a dose-dependent manner. We infer that sarin extensively influences oxidative homeostasis. Surprisingly, the central nervous system seems to be more resistant than the other organs.

• MeSH
• acetylcholinesterasa metabolismus   MeSH
• antioxidancia metabolismus   MeSH
• biochemické jevy * MeSH
• chemické bojové látky otrava   toxicita   MeSH
• cholinesterasové inhibitory otrava   toxicita   MeSH
• FRAP statistika a číselné údaje   MeSH
• glutathion analýza   krev   metabolismus   MeSH
• glutathionreduktasa analýza   krev   metabolismus   MeSH
• játra metabolismus   MeSH
• krysa rodu rattus MeSH
• látky reagující s kyselinou thiobarbiturovou analýza   metabolismus   MeSH
• ledviny metabolismus   MeSH
• mozek metabolismus   MeSH
• otrava krev   metabolismus   MeSH
• oxidační stres * účinky léků   MeSH
• potkani Wistar MeSH
• sarin * otrava   toxicita   MeSH
• slezina metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH