ABSTRACT
Chemical warfare agents continue to pose a real threat to humanity, despite their prohibition under the Chemical Weapons Convention. Sarin is one of the most toxic and lethal representatives of nerve agents. The methodology for the targeted analysis of known sarin metabolites has reached great heights, but little attention has been paid to the untargeted analysis of biological samples of victims exposed to this deadly poisonous substance. At present, the development of computational and statistical methods of analysis offers great opportunities for finding new metabolites or understanding the mechanisms of action or effect of toxic substances on the organism. This study presents the targeted LC-MS/MS determination of methylphosphonic acid and isopropyl methylphosphonic acid in the urine of rats exposed to a non-lethal dose of sarin, as well as the untarget urine analysis by LC-HRMS. Targeted analysis of polar acidic sarin metabolites was performed on a mixed-mode reversed-phase anion-exchange column, and untargeted analysis on a conventional reversed-phase C18 column. Isopropyl methylphosphonic acid was detected and quantified within 5 days after subcutaneous injection of sarin at a dose of 1/4 LD50. A combination of generalized additive mixed models and dose-response analysis with database searches using accurate mass of precursor ions and corresponding MS/MS spectra enabled us to propose new six potential biomarkers of biological response to exposure. The results confirm the well-known fact that sarin poisoning has a significant impact on the victims' metabolome, with inhibition of acetylcholinesterase being just the first step and trigger of the complex toxicodynamic response.
Subject(s)
Chemical Warfare Agents/analysis , Chemical Warfare Agents/poisoning , Chromatography, Liquid/methods , Sarin/poisoning , Sarin/urine , Tandem Mass Spectrometry/methods , Animals , Biomarkers/urine , Chemical Warfare Agents/standards , Limit of Detection , Male , Metabolomics/methods , Rats , Reference Standards , Reproducibility of Results , Sarin/standardsABSTRACT
On the battlefields of Syria, many innocent civilians have been killed or injured by sarin poisoning. In Malaysia in February 2017, a North Korean man was assassinated with VX at Kuala Lumpur International Airport. In the face of such threats, a more effective antidote against organophosphonate acetylcholinesterase (AChE) inhibitors is needed, one that can freely penetrate into the central nervous system (CNS) through the blood-brain barrier (BBB). In the 1995 Tokyo subway sarin attack, which produced more than 6,000 victims, 2-pyridinealdoxime methiodide was the most commonly used antidote in hospitals, but it was unable to prevent CNS damage and no other oximes have been approved for use in Japan. Ultimately, 12 people died, and many victims had severe neurological injuries or sequelae. Although more than 25 years have passed since the incident, progress has been slow in the development of a new antidote that can penetrate the BBB, restore AChE activity in the CNS, and definitely prevent brain injury. From the perspectives of countering terrorism and protecting innocent people from nerve agent attacks, the search for nerve agent antidotes should be accelerated with the goals of improving both survival and quality of life. This review gives an overview of a series of our studies on the development of a new antidote since the Tokyo subway sarin attack and emphasizes that there is unfortunately still no promising antidote for saving the CNS in Japan.
Subject(s)
Antidotes , Chemical Terrorism , Chemical Warfare Agents/poisoning , Cholinesterase Inhibitors/poisoning , Drug Development , Railroads , Sarin/poisoning , Blood-Brain Barrier/metabolism , Chemical Terrorism/prevention & control , Chemical Warfare Agents/metabolism , Cholinesterase Inhibitors/metabolism , Drug Development/trends , Humans , Pralidoxime Compounds , Sarin/metabolism , Time Factors , TokyoABSTRACT
OBJECTIVES: The Tokyo subway sarin attack in 1995 was an unprecedented act of terrorism that killed 13 people and sickened more than 6,000. The long-term somatic and psychological effects on its victims remain unknown. METHODS: We conducted analyses on the self-rating questionnaire collected annually by the Recovery Support Center (RSC) during the period from 2000 to 2009. The RSC is the only organization that has large-scale follow-up data about sarin attack victims. The prevalence of self-reported symptoms was calculated over 10 years. We also evaluated the prevalence of posttraumatic stress response (PTSR), defined as a score ≥ 25 on the Japanese-language version of the Impact of Event Scale-Revised. The multivariate Poisson regression model was applied to estimate the risk ratios of age, gender, and year factor on the prevalence of PTSR. RESULTS: Subjects were 747 survivors (12% of the total) who responded to the annual questionnaire once or more during the study period. The prevalence of somatic symptoms, especially eye symptoms, was 60-80% and has not decreased. PTSR prevalence was 35.1%, and again there was no change with time. The multivariate Poisson regression model results revealed "old age" and "female" as independent risk factors, but the passage of time did not decrease the risk of PTSR. CONCLUSIONS: Although symptoms in most victims of the Tokyo subway sarin were transient, this large-scale follow-up data analysis revealed that survivors have been suffering from somatic and psychological long-term effects.
Subject(s)
Chemical Terrorism , Chemical Warfare Agents/poisoning , Miosis/epidemiology , Sarin/poisoning , Stress Disorders, Post-Traumatic/epidemiology , Survivors/statistics & numerical data , Adolescent , Adult , Aged , Female , Follow-Up Studies , Humans , Male , Middle Aged , Miosis/chemically induced , Prevalence , Railroads , Risk Factors , Self Report/statistics & numerical data , Stress Disorders, Post-Traumatic/psychology , Survivors/psychology , Tokyo/epidemiology , Young AdultABSTRACT
Anticholinergic treatment is key for effective medical treatment of nerve agent exposure. Atropine is included at a 2 mg intramuscular dose in so-called autoinjectors designed for self- and buddy-aid. As patient cohorts are not available, predicting and evaluating the efficacy of medical countermeasures relies on animal models. The use of atropine as a muscarinic antagonist is based on efficacy achieved in studies in a variety of species. The dose of atropine administered varies considerably across these studies. This is a complicating factor in the prediction of efficacy in the human situation, largely because atropine dosing also influences therapeutic efficacy of oximes and anticonvulsants generally part of the treatment administered. To improve translation of efficacy of dosing regimens, including pharmacokinetics and physiology provide a promising approach. In the current study, pharmacokinetics and physiological parameters obtained using EEG and ECG were assessed in naïve rats and in sarin-exposed rats for two anticholinergic drugs, atropine and scopolamine. The aim was to find a predictive parameter for therapeutic efficacy. Scopolamine and atropine showed a similar bioavailability, but brain levels reached were much higher for scopolamine. Scopolamine exhibited a dose-dependent loss of beta power in naïve animals, whereas atropine did not show any such central effect. This effect was correlated with an enhanced anticonvulsant effect of scopolamine compared to atropine. These findings show that an approach including pharmacokinetics and physiology could contribute to improved dose scaling across species and assessing the therapeutic potential of similar anticholinergic and anticonvulsant drugs against nerve agent poisoning.
Subject(s)
Atropine/therapeutic use , Chemical Warfare Agents/poisoning , Sarin/poisoning , Scopolamine/therapeutic use , Animals , Atropine/blood , Atropine/pharmacokinetics , Atropine/pharmacology , Brain Chemistry/drug effects , Cholinergic Antagonists , Electrocardiography/drug effects , Electroencephalography/drug effects , Male , Mice , Rats, Wistar , Sarin/antagonists & inhibitors , Scopolamine/blood , Scopolamine/pharmacokinetics , Scopolamine/pharmacology , Telemetry/methodsABSTRACT
Organophosphorus nerve agents (NA) inhibit acetylcholinesterase (AChE) which results in the over-stimulation of both the central and peripheral nervous systems, creating a toxic syndrome that can be lethal if left untreated (Cannard, 2006). It is standard practice to treat Sarin (GB) intoxication with an oxime, an antimuscarinic such as atropine and an anticonvulsant. Three common oximes are available: HI-6, Pralidoxime (2-PAM) and Obidoxime (Obi), all possess a nucleophile that can break the NA-AChE covalent bond. However, each oxime's efficacy profile against various agents is different (Thiermann and Worek, 2018). In an effort to broaden therapeutic efficacy against a range of possible NA's, consideration should be given to the use of two oximes in combination. Using a guinea pig model, the first arm of this study was to determine the pharmacokinetics (PK) of HI-6 DMS, 2-PAM chloride and Obi chloride (at autoinjector equivalent doses) following intramuscular (i.m.) co-administration along with atropine to replicate either a single isometrically scaled dose (referred to in this study as a single autoinjector equivalent) of 2-PAM (and equimolar doses of Obi and HI-6) or double doses (referred to in this study as two autoinjector equivalents). The second arm of the study evaluated the efficacy of Obi and 2-PAM individually at a single or double autoinjector dose and also in combination against GB exposure. Pharmacokinetic profiles of each oxime were evaluated for both arms of the study and no significant change in parameters were reported. Improved cholinesterase reactivation was observed in a dose dependent manner with combined therapy showing similar reactivation to individual oximes alone at a two autoinjector equivalent dose. Seizure activity was reduced when combined oxime therapy was administered. This improvement was also reflected in the Racine seizure index score assigned at the end of the experimental period. To the best of our knowledge, this study is the first to evaluate and compare the pharmacokinetics of three oximes and the combination of two oximes (2-PAM and Obi) administered in naïve animals or those exposed to GB. Combined oxime therapy (Obi and 2-PAM) resulted in improved seizure control, increased cholinesterase reactivation peripherally and centrally and improved behavioral signs (Racine score). This study provides evidence that combination of oximes is effective, does not result in adverse events and that the pharmacokinetics of each oxime are not affected when administered in combination.
Subject(s)
Nerve Agents/poisoning , Oximes/pharmacokinetics , Oximes/therapeutic use , Sarin/poisoning , Acetylcholinesterase/metabolism , Animals , Drug Therapy, Combination , Electrocardiography/drug effects , Electroencephalography/drug effects , Guinea Pigs , Male , Oximes/administration & dosageABSTRACT
Organophosphorus (OP)1 nerve agents pose a severe toxicological threat, both after dissemination in military conflicts and by terrorists. Hydrolytic enzymes, which may be administered into the blood stream of victims by injection and can decompose the circulating nerve agent into non-toxic metabolites in vivo, could offer a treatment. Indeed, for the phosphotriesterase found in the bacterium Brevundimonas diminuta (BdPTE),2 engineered versions with improved catalytic efficiencies have been described; yet, their biochemical stabilities are insufficient for therapeutic use. Here, we describe the application of rational protein design to develop novel mutants of BdPTE that are less susceptible to oxidative damage. In particular, the replacement of two unpaired cysteine residues by more inert amino acids led to higher stability while maintaining high catalytic activity towards a broad spectrum of substrates, including OP pesticides and V-type nerve agents. The mutant BdPTE enzymes were produced in Escherichia coli, purified to homogeneity, and their biochemical and enzymological properties were assessed. Several candidates both revealed enhanced thermal stability and were less susceptible to oxidative stress, as demonstrated by mass spectrometry. These mutants of BdPTE may show promise for the treatment of acute intoxications by nerve agents as well as OP pesticides.
Subject(s)
Antidotes/pharmacology , Bacterial Proteins/pharmacology , Caulobacteraceae/enzymology , Nerve Agents/poisoning , Organophosphate Poisoning/drug therapy , Organophosphorus Compounds/toxicity , Phosphoric Triester Hydrolases/pharmacology , Antidotes/metabolism , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Caulobacteraceae/genetics , Drug Stability , Enzyme Stability , Hot Temperature , Mutation , Organophosphate Poisoning/enzymology , Organothiophosphorus Compounds/poisoning , Oxidation-Reduction , Phosphoric Triester Hydrolases/genetics , Phosphoric Triester Hydrolases/metabolism , Protein Denaturation , Recombinant Proteins/pharmacology , Sarin/poisoning , Soman/poisoningABSTRACT
INTRODUCTION: Having experienced the Tokyo subway sarin attack in 1995, Japan has established extremely strict rules on handling injured victims before they are sent to a hospital. As a result, it takes a long time before rescue actions are taken. This report aims to propose a reform to change the system that focuses on saving lives. METHODS: First, the issues in firefighting on sites that currently present problems in Japan were identified. Then, Japanese guidelines were compared with those that were considered in other countries. Based on this, an ideal way of running rescue operations was examined, and a proposal to save many lives was made. This research was conducted with funding from the Ministry of Health, Labour, and Welfare of Japan (MHLW; Chiyoda, Tokyo, Japan). RESULTS: In addition to preventing secondary injuries, the temporal aspect of rescuing people early with the clear goal of saving many lives was emphasized. Priority was given to measures against nerve agents to prevent secondary injuries, which put the rescuers' lives at risk. Possible decontamination methods were pursued before choosing the one that was most appropriate. A linear algorithm was used to determine which decontamination method could be started immediately, and then the gradual use of equipment was recommended. Even if Level A personal protective equipment (PPE) and other dedicated equipment and materials cannot be procured, the possibility of starting rescue activities under certain condition using regular equipment was pointed out. The need for a system for possible victims who would require support, such as foreigners, the handicapped, and elderly people, was also identified. Japan limits the scope of activities that can be undertaken by emergency medical technicians (EMTs) on-site. The way in which on-site medical care can be provided with future legal revisions in mind was also discussed. CONCLUSION: There is an urgent need to build a framework in which rescue activities can take place so that the number of deaths would not rise, even if sarin and other poisons are scattered.
Subject(s)
Chemical Terrorism , Disaster Planning , Emergency Medical Services/standards , Rescue Work , Humans , Japan , Personal Protective Equipment , Sarin/poisoningABSTRACT
Organophosphorus (OP) nerve agent poisoning made the headlines in 2018 with the nerve agent 'Novichok' poisonings in Salisbury, England. This event highlighted a gap in the knowledge of most clinicians in the UK. In response, this special article aims to enlighten and signpost anaesthetists and intensivists towards the general management of OP nerve agent poisoned patients. Drawing on a broad range of sources, we will discuss what OP nerve agents are, how they work, and how to recognise and treat OP nerve agent poisoning. OP nerve agents primarily act by inhibiting the enzyme acetylcholinesterase, causing an acute cholinergic crisis; death usually occurs through respiratory failure. The antimuscarinic agent atropine, oximes (to reactivate acetylcholinesterase), neuroprotective drugs, and critical care remain the mainstays of treatment. The risk to medical staff from OP poisoned patients appears low, especially if there is a thorough decontamination of the poisoned patient and staff wear appropriate personal protective equipment. The events in Salisbury in the past year were shocking, and the staff at Salisbury District General Hospital performed admirably in treating those affected by Novichok nerve agent poisoning. We eagerly anticipate their future clinical publications so that the medical community might learn from their valuable experiences.
Subject(s)
Nerve Agents/poisoning , Organophosphate Poisoning/therapy , Chemical Warfare Agents/poisoning , Decontamination , Humans , Organophosphate Poisoning/mortality , Sarin/poisoningABSTRACT
Efficacy of two oximes treatments evaluated during inhalation of sarin vapor (LCt50, 755.9 mg/min/m3) in simulated real scenario in vivo. Majority of mice either became moribund or died within 1-2 min during exposure to multifold-lethal concentrations of sarin vapor. Protection indices were determined by exposing to sarin vapor in two sessions, 1 min exposure followed by treatments with or without HNK-102 (56.56 mg/kg, im) or 2-PAM (30 mg/kg, im) and atropine (10 mg/kg, ip), and again exposed for remaining 14 min. Protection offered by HNK-102 was found to be four folds higher compared to 2-PAM in the same toxic environment. Secondly, sub-lethal concentration of sarin vapor (0.8 × LCt50 or 605 mg/min/m3), 24 h post investigations revealed that the oximes could not reactivate brain and serum acetylcholinesterase (AChE) activity. The treatments prevented increase in protein concentration (p < .05) and macrophages infiltration compared to sarin alone group in broncho-alveolar lavage fluid. Lung histopathology showed intense peribronchial infiltration and edema with desquamating epithelial lining and mild to moderate alveolar septal infiltration in sarin and atropine groups, respectively. Noticeable peeling-off observed in epithelial lining and sporadic mild infiltration of epithelial cells at bronchiolar region in 2-PAM and HNK-102 groups, respectively. The oximes failed to reactivate AChE activity; however, the mice survived up to 6.0 × LCt50, proved involvement of non-AChE targets in sarin toxicity. Atropine alone treatment was found to be either ineffective or increased the toxicity. HNK-102, exhibited better survivability with lung protection, can be considered as a better replacement for 2-PAM to treat sarin inhalation induced poisoning.
Subject(s)
Chemical Warfare Agents/poisoning , Inhalation Exposure/adverse effects , Oximes/pharmacology , Pralidoxime Compounds/pharmacology , Sarin/poisoning , Acetylcholinesterase/blood , Animals , Dose-Response Relationship, Drug , Gas Poisoning/prevention & control , Lethal Dose 50 , Lung/drug effects , Lung/pathology , Male , Mice , Oximes/chemistry , Pralidoxime Compounds/chemistry , Sarin/toxicityABSTRACT
Rats poisoned with sarin enter into ahyper-cholinergic crisis characterized by excessive salivation, respiratory distress, tremors, seizures, and death. Through the use of rescue medications and an anticonvulsant, death can be avoided in many animals, with the long-term consequences of poisoning partly ameliorated, especially when countermeasures are made available immediately after exposure. However, when anticonvulsant measures are delayed by as little as 30 min, clinical, neurological, cognitive, and psychiatric abnormalities may persist long after the initial exposure. This study sought to determine if the addition of the NMDA receptor antagonist Ketamine to human standard-of-care countermeasures consisting of two rescue medications (2-PAM and atropine) and an anti-convulsant (Midazolam), would afford protection against persistent neurobiological compromise. Rats were exposed to sarin (105 µg/kg via subcutaneous injection), and treated 1 min later with 2-PAM and Atropine Methyl Nitrate (IM) to minimize mortality. One of four anti-convulsant protocols was then initiated at 50 min postsarin:Midazolam alone (MDZ, a single injection (IM) at 0.66 mg/kg); Ketamine alone (KET, a series of five injections (IM) of Ketamine at 7.5 mg/kg, 90 min apart); Midazolam + low dose Ketamine (MDZ + lowKET, a single injection of Midazolam (IM) at 0.66 mg/kg, plus five sequential doses of ketamine (IM) at 2.5 mg/kg, starting at the time of Midazolam dosing and then 90 min apart); Midazolam + high dose Ketamine (MDZ + highKET, a single injection of Midazolam (IM) at 0.66 mg/kg, plus five sequential injections of 7.5 mg/kg Ketamine (IM), starting at the time of Midazolam dosing and then 90 min apart). Animals were preassigned to groups culled at post-exposure Days 1, 7 or 30, for histopathology. For all surviving animals, EEG activity was monitored through skull electrodes for 24-h beginning immediately after sarin exposure. Surviving animals also underwent 24-h EEG monitoring on Days 6, 13, and/or 29, post-sarin. Memory assessment using the Morris Water Maze was performed on Days 1, 4, 7, 14 and 30. Following sarin exposure, 85% of surviving animals demonstrated status epilepticus within 20 min. Each of the anti-convulsant protocols was sufficient to stop convulsions within 1 h of anti-convulsant administration, but all of the animals still showed signs of electrographic status for an additional 2-12 h, without substantial differentiation between treatment groups. However, for post-sarin hours 13-24, the MDZ + highKET group showed significantly less severe EEG abnormalities than the MDZ and KET groups (Mood's Median Test, p < 0.005). At one month post-exposure, 90% of animals that had received Midazolam alone still showed evidence of some epileptiform activity. In contrast, 90% of animals that had received Midazolam + high dose Ketamine combination therapy had EEG profiles that were within normal limits. This difference in EEG outcomes was highly significant (Mood's Median Test, p < 0.001). Likewise, on the water maze, the majority of animals that had received Midazolam combined with either high or low dose Ketamine therapy returned to near baseline levels of mnemonic performance within 2 weeks, whereas the majority of the animals that had received midazolam alone or ketamine alone demonstrated persistent and significant memory impairments even at one month postexposure (Mood's Median Test, p < 0.005). With respect to neuronal necrosis, animals in the MDZ + highKET group showed significantly less overall damage than animals in other treatment groups (Mood's Median Test, p < 0.001). Of special note were findings in the hippocampus, where only 12% of animals in the MDZ + highKET group showed evidence of necrosis on H&E staining, whereas 100% of animals in the KET group, 70% of animals in the MDZ group, and 40% of animals in the MDZ + lowKET group showed evidence of hippocampal necrosis. Overall, the data demonstrate that Ketamine augmentation of an atropine, 2PAM, and Midazolam standard-ofcare for sarin exposure provides clinically-relevant additional protection against the negative neurobiological consequences of sarin, even when initiation of the anti-convulsant countermeasures is delayed by 50 min.
Subject(s)
Ketamine/administration & dosage , Organophosphate Poisoning/physiopathology , Organophosphate Poisoning/therapy , Sarin/poisoning , Standard of Care/trends , Animals , Anticonvulsants/administration & dosage , Chemical Warfare Agents/poisoning , Combined Modality Therapy/methods , Electroencephalography/drug effects , Electroencephalography/methods , Excitatory Amino Acid Antagonists/administration & dosage , Male , Maze Learning/drug effects , Maze Learning/physiology , Organophosphate Poisoning/pathology , Rats , Rats, Inbred F344 , Treatment OutcomeABSTRACT
BACKGROUND: The aim of our study was to compare the ability of two combinations of oximes (HI-6 + trimedoxime and HI-6 + K203) with atropine to counteract acute sarin-induced brain damage with the efficacy of antidotal treatment involving single oxime (HI-6) and atropin using in vivo methods. METHODS: Brain damage and neuroprotective effects of antidotal treatment were evaluated in rats poisoned with sarin at a sublethal dose (108 µg/kg i.m.; 90% LD50) using histopathological, Fluoro-Jade B and Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) analysis 24 h after sarin administration. RESULTS: Both combinations of oximes reduce the number of rats that died before the end of experiment compared to non-treated sarin poisoning and sarin poisoning treated with HI-6 and atropine. In the case of treatment of sarin poisoning with HI-6 in combination with K203, all rats survived till the end of experiment. HI-6 with atropine was able to reduce sarin-induced brain damage, however, both combinations were slightly more effective. CONCLUSIONS: The oxime HI-6 in combination with K203 and atropine seems to be the most effective. Thus, both tested oxime combinations bring a small benefit in elimination of acute sarin-induced brain damage compared to single oxime antidotal therapy.
Subject(s)
Antidotes/therapeutic use , Neurotoxicity Syndromes/drug therapy , Oximes/therapeutic use , Sarin/poisoning , Animals , Drug Therapy, Combination , Rats, WistarABSTRACT
Pyridinium oximes are strong nucleophiles and many are effective reactivators of organophosphate-inhibited cholinesterase (ChE). However, the current oxime reactivators are ineffective at crossing the blood-brain barrier and reactivating brain ChE in the intact organism. Our laboratories have developed a series of substituted phenoxyalkyl pyridinium oximes (US patent 9,227,937 B2) with the goal of identifying reactivators effective in crossing the blood-brain barrier. The first 35 of the series were found to have similar in vitro efficacy as reactivators of ChE inhibited by a sarin surrogate (phthalimidyl isopropyl methylphosphonate, PIMP) or a VX surrogate (nitrophenyl ethyl methylphosphonate, NEMP) in bovine brain preparations as previously observed in rat brain preparations. A number of these novel oximes have shown the ability to decrease the level of ChE inhibition in the brains of rats treated with a high sublethal dosage of either a sarin surrogate (nitrophenyl isopropyl methylphosphonate, NIMP) or the VX surrogate NEMP. Levels of reactivation at 2 h after oxime administration were up to 35% while the currently approved therapeutic, 2-PAM, yielded no reduction in brain ChE inhibition. In addition, there was evidence of attenuation of seizure-like behavior with several of the more effective novel oximes, but not 2-PAM. Therefore these novel oximes have demonstrated an ability to reactivate inhibited ChE in brain preparations from two species and in vivo data support their ability to enter the brain and provide a therapeutic action. These novel oximes have the potential to be developed into improved antidotes for nerve agent therapy.
Subject(s)
Acetylcholinesterase/metabolism , Brain/drug effects , Cholinesterase Inhibitors/isolation & purification , Cholinesterase Reactivators/pharmacology , Organothiophosphorus Compounds/poisoning , Oximes/pharmacology , Sarin/poisoning , Acetylcholinesterase/chemistry , Animals , Brain/enzymology , Cattle , Cholinesterase Inhibitors/poisoning , Cholinesterase Reactivators/chemistry , Cholinesterase Reactivators/therapeutic use , Chromatography, High Pressure Liquid , Male , Organophosphate Poisoning/drug therapy , Organophosphate Poisoning/metabolism , Oximes/chemistry , Oximes/therapeutic use , Pyridines/chemistry , Rats , Rats, Sprague-Dawley , Tandem Mass SpectrometryABSTRACT
The antidotal treatment of organophosphates (OP) nerve agents (NA) poisoning is based on anticholinergics (e.g. atropine) combined with oxime reactivators (e.g. 2PAM) of acetylcholinesterase (AChE). This treatment is symptomatic and does not degrade the OP. New small-molecule OP scavengers were developed as bifunctional hybrids. Their molecular design was based on combining a nucleophile that directly degrades OP with a moiety that reactivates OP-inhibited AChE. The OP degrading moiety is either benzhydroxamic acid (BHA) or 4-pyridinehydroxamic acid (4PHA) coupled via (CH2)n, (n = 1 or 3) to 2PAM. Three newly synthesized oxime-hydroxamate hybrids: 2PAMPr4PHA, 2PAMMeBHA and 2,4-DiPAMMeBHA were found to detoxify sarin, cyclosarin and soman in solution at 3-10-fold faster rate than 2PAM and to reactivate OP-AChE in vitro. 2PAMPr4PHA displayed 18-fold faster reactivation than 2-PAM of cyclosarin-inhibited HuAChE (kr = 3.6 × 102 vs. 0.2 × 102 M-1min-1, respectively, 37 °C). These hybrids inhibited AChE reversibly, IC50 = 16-48 µM, thereby decreasing the inhibition rates by OPs. The LD50 (im) of 2PAMPr4PHA, 2PAMMeBHA and 2,4DiPAMMeBHA are >568, 508 and >506 µmol/kg in rats and 144, 203 and >506 µmol/kg in guinea pigs. The rate of blood ChE recovery by the hybrids administered either pre- or post-exposure to 0.8xLD50 sarin was comparable or faster than 2PAM. Antidotal efficacy of 2PAMPr4PHA, 2PAMMeBHA and 2,4DiPAMMeBHA administered with atropine, as pre-treatment to sarin in rats (im), yielded protection ratios (PR) 11.6, 11.5 and 4.7, respectively, vs. 5.5 with 2PAM. Post-treatment against various OPs in rats and guinea-pigs yielded PRs higher or similar to that of 2 PAM. Our in vivo data indicates that some hybrids may serve as efficient small molecule scavengers for mitigating the toxicity of OP NAs.
Subject(s)
Nerve Agents/toxicity , Neurotoxins/toxicity , Small Molecule Libraries/pharmacology , Acetylcholinesterase/blood , Acetylcholinesterase/metabolism , Animals , Antidotes/pharmacology , Cholinesterase Inhibitors/pharmacology , Cholinesterase Reactivators/pharmacology , Guinea Pigs , Humans , Hydroxamic Acids/chemistry , Inhibitory Concentration 50 , Kinetics , Male , Organophosphates/toxicity , Organophosphorus Compounds/toxicity , Organothiophosphorus Compounds/toxicity , Oximes/chemistry , Phosphorylation/drug effects , Rats, Sprague-Dawley , Sarin/poisoning , Time Factors , Toxicity Tests, AcuteSubject(s)
Chemical Terrorism , Sarin/poisoning , Humans , Railroads , Stress Disorders, Post-Traumatic , Time Factors , TokyoABSTRACT
The use of nerve agents such as sarin is as much a threat today as any other time in our history. The events in Syria in 2013 are proof of this. "The Obama administration asserted Sunday for the first time that the Syrian government used the nerve gas sarin to kill more than 1,400 people (August 21, 2013) in the world's gravest chemical weapons attack in 25 years." With these recent events clear in our mind, we must focus on the horrific nature of these chemical agents to devise a strategy that will enable first responders to counteract these insidious chemicals. This paper presents research on a physiologically based pharmacokinetic model to determine whether the current treatment protocol prescribed by the Center for Disease Control (CDC) and the US Army is effective in treating victims suffering from acute exposure symptoms. The model was used to determine what treatment should be used for victims suffering from mild exposure symptoms. The results indicate that the current CDC and US Army treatment is effective, but treatment with oxime therapy was not effective in alleviating symptoms of mild exposure. By applying these results, an effective treatment protocol was developed.
Subject(s)
Antidotes/pharmacokinetics , Chemical Warfare Agents/pharmacokinetics , Organophosphate Poisoning/drug therapy , Oximes/pharmacokinetics , Sarin/pharmacokinetics , Antidotes/therapeutic use , Centers for Disease Control and Prevention, U.S. , Chemical Warfare Agents/poisoning , Humans , Models, Theoretical , Oximes/therapeutic use , Practice Guidelines as Topic , Pralidoxime Compounds/therapeutic use , Sarin/poisoning , Systems Analysis , United StatesABSTRACT
INTRODUCTION AND OBJECTIVE: Acetylcholinesterase (AChE) and cholinergic receptors play an important role in the immune system, including lymphocyte-induced angiogenesis. However, their exact role is not fully understood. The presented work tests the influence of isopropyl methylphosphonofluoridate (IMPF), an irreversible inhibitor of AChE, on selected immune parameters associated with angiogenesis in mice. The levels of VEGF, bFGF, TNF-α, and IFN-γ production were measured, together with the ability of lymphoid spleen cells to induce local GvH reaction after a single dose of IMPF. MATERIALS AND METHOD: Experiments were performed in male BALB/c mice. Acetylcholinesterase activity in erythrocytes was determined by the Ellman`s procedure. Levels of cytokines were measured in serum using standard commercial ELISA kits. Influence of IMPF intoxication upon angiogenesis was examined by the LIA test, according to the Sidky and Auerbach procedure. RESULTS: The results showed a 6- and 8-fold increase in VEGF at days 1 and 7 of the experiment, respectively, as well as a decrease (at days 14 and 21 after administration), followed by a significant increase (day 1) in bFGF levels. A statistically significant decrease in the concentration of IFN-γ was observed throughout all experiments. The maximum decrease in the level of TNF-α was found at days 1 and 7 after administration of IMPF. Additionally, a significant decrease was found in the ability to form new blood vessels following IMPF administration. CONCLUSIONS: This study revealed that IMPF has a significant effect on the regulation of lymphocyte-induced angiogenesis, which is related with the modulation of angiogenic and pro-inflammatory cytokines secretion. The observed differences suggest a possible derangement of certain elements of the neuronal and/or non-neuronal cholinergic system.
Subject(s)
Acetylcholinesterase/metabolism , Cholinesterase Inhibitors/poisoning , Cytokines/metabolism , Graft vs Host Reaction/drug effects , Lymphocytes/drug effects , Neovascularization, Physiologic/drug effects , Sarin/poisoning , Animals , Male , Mice , Mice, Inbred BALB C , Mice, Inbred DBA , Spleen/drug effectsABSTRACT
Organic phosphate pesticides were used worldwide after World War II and experiences on poisoning and treatment have been accumulated. An organic phosphate "nerve agent" Sarin was used in two terrorist attacks in Japan in the 1990s. Sarin effects on humans were well documented in these two incidents. Sarin gas inhalation caused instantaneous death by respiratory arrest in several victims in Matsumoto. Severely injured victims presenting with coma and generalized convulsion were resuscitated and recovered rapidly without sequelae. Miosis and blurred-dark vision, ocular pain, copious secretions from respiratory and gastrointestinal tract (muscarinic effects), and headache were common in severely to slightly affected victims. Plasma cholinesterase (ChE) activity decreased in parallel with the severity of signs and symptoms in victims. Oximes, atropine sulphate, diazepam, and ample intravenous infusion were effective treatments. Follow-up examinations on victims were conducted up to 10 years in Matsumoto, and 5 years in Tokyo. No neurological sequelae or abnormalities were observed after 1 year, except for a few EEG abnormalities or delay in sensory nerve conduction velocity. Posttraumatic stress disorder (PTSD) was observed in several of the victims in the 5-year follow up, irrespective of the severity of poisoning at Matsumoto. Psychological symptoms continue in victims of both incidents.
Subject(s)
Cholinesterase Inhibitors/poisoning , Cholinesterases/blood , Nervous System Diseases/therapy , Sarin/poisoning , Acute Disease , Animals , Chemical Terrorism , Humans , Japan , Nervous System Diseases/chemically induced , Sarin/chemistryABSTRACT
On the night of 21 August 2013, sarin was dispersed in the eastern outskirts of Damascus, killing 1400 civilians and severely affecting thousands more. This article aims to delineate the clinical presentation and management of a mass casualty event caused by a nerve agent as shown in the social media. Authors searched YouTube for videos uploaded of this attack and identified 210 videos. Of these, 67 met inclusion criteria and were evaluated in the final analysis.These videos displayed 130 casualties; 119 (91.5%) of which were defined as moderately injured or worse. The most common clinical signs were dyspnea (53.0%), diaphoresis (48.5%), and loss of consciousness (40.7%). Important findings included a severe shortage of supporting measures and lack of antidotal autoinjectors. Decontamination, documented in 25% of the videos, was done in an inefficient manner. Protective gear was not noticed, except for sporadic use of latex gloves and surgical masks.This is believed to be the first time that social media was used to evaluate clinical data and management protocols to better prepare against future possible events.
Subject(s)
Chemical Terrorism , Mass Casualty Incidents , Sarin/poisoning , Social Media , Atropine/therapeutic use , Child , Cholinergic Antagonists/therapeutic use , Decontamination , Disaster Planning , Female , Humans , Infant , Injections, Intravenous , Male , Poisoning/complications , Poisoning/diagnosis , Poisoning/therapy , Syria/epidemiologyABSTRACT
This article presents a framework for economic consequence analysis of terrorism countermeasures. It specifies major categories of direct and indirect costs, benefits, spillover effects, and transfer payments that must be estimated in a comprehensive assessment. It develops a spreadsheet tool for data collection, storage, and refinement, as well as estimation of the various components of the necessary economic accounts. It also illustrates the usefulness of the framework in the first assessment of the tradeoffs between enhanced security and changes in commercial activity in an urban area, with explicit attention to the role of spillover effects. The article also contributes a practical user interface to the model for emergency managers.
Subject(s)
Commerce , Security Measures/economics , Terrorism/prevention & control , Air Pollutants/poisoning , Cost-Benefit Analysis , Humans , Models, Economic , Models, Statistical , Risk Assessment , Sarin/poisoning , Television/economics , Terrorism/economics , United States , Urban PopulationABSTRACT
Monte Carlo method has been used as a computational tool for building QSAR models for the reactivation of sarin inhibited acetylcholinesterase (AChE) by quaternary pyridinium oximes. Simplified molecular input line entry system (SMILES) together with hydrogen-suppressed graph (HSG) was used to represent molecular structure. Total number of considered oximes was 46 and activity was defined as logarithm of the AChE reactivation percentage by oximes with concentration of 0.001 M. One-variable models have been calculated with CORAL software for one data split into training, calibration and test set. Computational experiments indicated that this approach can satisfactorily predict the desired endpoint. Best QSAR model had the following statistical parameters: for training set r2=0.7096, s=0.177, MAE=0.148; calibration set: r2=0.6759, s=0.330, MAE=0.271 and test set: r2=0.8620, s=0.182, MAE=0.150. Structural indicators (SMILES based molecular fragments) for the increase and the decrease of the stated activity are defined. Using defined structural alerts computer aided design of new oxime derivatives with desired activity is presented.