Nerve Agent Poisoning Research Articles

A long-lasting poison scavenger

Drug Development Nerve agents are neurotoxic compounds found in pesticides and chemical weapons. They act by blocking the transmission of nerve impulses to the muscles, and exposure can be fatal within minutes. Zhang et al. developed a nanoparticle-based bioscavenger that breaks down organophosphate nerve agents into innocuous compounds. Prophylactic treatment of rats and guinea pigs confirmed low immunogenicity and good biodistribution. Treated animals were protected from repeated exposure to the nerve agent sarin over 7 days. This nanoscavenger might thus help prevent nerve-agent poisoning in at-risk subjects. Sci. Transl. Med. 11 , eaau7091 (2019).

Drone in NBC disaster

Nuclear, Biological and chemical disasters are tragic and should never happen. Unavoidably occurred, access and reach are difficult because rescue personnel are exposed to hazards. Drone is an unmanned aerial vehicle that can be operated by remote control or autonomous aviation. It has some advantages in NBC disaster as followings:First, drone can take a picture and record the scene in contaminated zone. Communication with injured is also possible without exposure to rescue team. Triage can be performed by analysis of movement, breathing and responsiveness, etc.Second, atropine and oxime are essential to nerve agent poisoning. It can be delivered by drone only inside contaminated zone for survivors.Third, drone can collect specimen without human exposure. Investigator can analyze the extent of pollution in remote laboratory with this specimen.Fourth, survivor can be evacuated from disaster area by drone itself. This operation needs heavy capability that would lift patients.I hope that NBC disaster could be overcome with this useful modern convenience.

Efficacy of antidotes and their combinations in the treatment of acute carbamate poisoning in rats

BackgroundPhysostigmine and its analogues neostigmine, pyridostigmine and rivastigmine are carbamates nowadays used in many indications, including antidotal effects against antimuscarinic poisonings, reversal of competitive neuromuscular block, myasthenia gravis, Alzheimer’s disease and prophylaxis against nerve agent intoxications. Use of these medicinal carbamates, but also of carbamate insecticides, created need for research into the potential and mechanisms of action of several antidotes against carbamate poisonings, including anticholinergics and oximes. AimThe goal of this experimental study was to ascertain the life-preserving potential of anticholinergics atropine, hexamethonium and d-tubocurarine, oxime HI-6 and their combinations in rats poisoned with physostigmine or pyridostigmine. Materials and methodsExperiments were performed in Wistar rats. Carbamates were injected subcutaneously (sc) and antidotes intramuscularly (im). Median lethal dose (LD50) in animals treated with antidotes were compared to the ones in saline-treated rats and protective ratios (PRs) were calculated. Atropine (5, 10 and 20 mg/kg), hexamethonium (5, 10 and 20 mg/kg), d-tubocurarine (0.005, 0.010 and 0.020 mg/kg) and oxime HI-6 (25, 50 and 100 mg/kg) were used as monotherapies and in dual combinations, where atropine was the obligatory antidote. Biochemical experiments consisted in measuring of the cholinesterase activities in brain, whole blood and diaphragm in rats 5, 15, 30, 60, 120 and 240 min after poisoning with 0.8 LD50 of physostigmine or pyridostigmine. ResultsAll the tested antidotes assured some degree of protection against the two carbamates. Atropine and hexamethonium produced better protection in physostigmine-poisoned rats, while d-tubocurarine and HI-6 were more efficacious in pyridostigmine-intoxicated animals. Oxime HI-6 50 mg/kg reactivated acetylcholinesterase (AChE) in brain inhibited by physostigmine and in diaphragm inhibited by pyridostigmine. ConclusionsMechanism of physostigmine-induced lethal effect is predominantly central and it involves inhibition of brain AChE, while pyridostigmine produces the same effect exclusively outside the central nervous system, by inhibiting AChE in the respiratory muscles. As a consequence, increasing doses of atropine and their combination with hexamethonium assure excellent protection against physostigmine toxicity, while the best protection against pyridostigmine is provided by a strictly peripherally acting antinicotinic d-tubocurarine and bispyridinium oxime HI-6. The oxime acts as antidote against physostigmine and pyridostigmine poisoning by reactivating AChE in the brain and diaphragm, respectively.

Structure-Based Optimization of Nonquaternary Reactivators of Acetylcholinesterase Inhibited by Organophosphorus Nerve Agents.

Acetylcholinesterase (AChE), a key enzyme in the central and peripheral nervous systems, is the principal target of organophosphorus nerve agents. Quaternary oximes can regenerate AChE activity by displacing the phosphyl group of the nerve agent from the active site, but they are poorly distributed in the central nervous system. A promising reactivator based on tetrahydroacridine linked to a nonquaternary oxime is also an undesired submicromolar reversible inhibitor of AChE. X-ray structures and molecular docking indicate that structural modification of the tetrahydroacridine might decrease inhibition without affecting reactivation. The chlorinated derivative was synthesized and, in line with the prediction, displayed a 10-fold decrease in inhibition but no significant decrease in reactivation efficiency. X-ray structures with the derivative rationalize this outcome. We thus show that rational design based on structural studies permits the refinement of new-generation pyridine aldoxime reactivators that may be more effective in the treatment of nerve agent intoxication.

Behavioral, Pharmacokinetic, and Cardiovascular Evaluation of Candidate Oximes in African Green Monkeys.

Oxime reactivators are critical antidotes after organophosphate pesticide or nerve agent poisoning, directly restoring the function of inhibited acetylcholinesterase. In the continuing search for more broad-spectrum acetylcholinesterase reactivators, this study evaluated one of the leading next-generation oxime reactivators: methoxime, (1,1'-trimethylene bis[4-(hydroxyimino)methyl]pyridinium dichloride (MMB-4). The pharmacokinetics of both salts of MMB-4 (dichloride [2Cl] and dimethanesulphonate [DMS]) were characterized across a range of relevant doses (19, 58, and 116 µmol/kg, intramuscular) in a nonhuman primate model (male African green monkeys), and only subtle differences were observed between the salts. Additionally, the behavioral and cardiovascular safety of these MMB-4 salts was compared directly to other available oximes (HI-6 2Cl, HI-6 DMS, and pyridine-2-aldoxime chloride (2-PAM Cl)) at comparable projected doses. Automated operant behavioral tests were used to examine attention, motivation, visual discrimination, concept execution, and fine motor coordination after high doses of all oxime salts, and of all oximes studied, only the highest dose of 2-PAM Cl (447 µmol/kg) disrupted behavioral performance. Likewise, the effects of a range of doses of MMB-4 2Cl or DMS, HI-6 2Cl or DMS, or 2-PAM Cl on cardiovascular parameters were measured in African green monkeys implanted with telemetry devices. Only a small transient decrease in pulse pressure was observed following administration of the highest dose of MMB-4 DMS (116 µmol/kg). Thus, MMB-4 salts, up to the 9× equivalent of a projected autoinjector dose in humans, did not produce behavioral or cardiovascular toxicity in African green monkeys in the current study, and the pharmacokinetic parameters were orderly and predictable.

Evaluating mice lacking serum carboxylesterase as a behavioral model for nerve agent intoxication

Mice and other rodents are typically utilized for chemical warfare nerve agent research. Rodents have large amounts of carboxylesterase in their blood, while humans do not. Carboxylesterase nonspecifically binds to and detoxifies nerve agent. The presence of this natural bioscavenger makes mice and other rodents poor models for studies identifying therapeutics to treat humans exposed to nerve agents. To obviate this problem, a serum carboxylesterase knockout (Es1 KO) mouse was created. In this study, Es1 KO and wild type (WT) mice were assessed for differences in gene expression, nerve agent (soman; GD) median lethal dose (MLD) values, and behavior prior to and following nerve agent exposure. No expression differences were detected between Es1 KO and WT mice in more than 34 000 mouse genes tested. There was a significant difference between Es1 KO and WT mice in MLD values, as the MLD for GD-exposed WT mice was significantly higher than the MLD for GD-exposed Es1 KO mice. Behavioral assessments of Es1 KO and WT mice included an open field test, a zero maze, a Barnes maze, and a sucrose preference test (SPT). While sex differences were observed in various measures of these tests, overall, Es1 KO mice behaved similarly to WT mice. The two genotypes also showed virtually identical neuropathological changes following GD exposure. Es1 KO mice appear to have an enhanced susceptibility to GD toxicity while retaining all other behavioral and physiological responses to this nerve agent, making the Es1 KO mouse a more human-like model for nerve agent research.

ACMT Position Statement: Alternative or Contingency Countermeasures for Acetylcholinesterase Inhibiting Agents.

First responders and health care providers must prepare to provide care for patients poisoned by acetylcholinesterase (AchE) inhibitor chemical warfare agents or pesticides. However, pre-deployed medical countermeasures (MCMs) may not be sufficient due to production and delivery interruption, rapid depletion of contents during a response, expiration of MCM components, or lack of local availability of approved MCMs. To augment supplies of community-based and forward-deployed nerve agent countermeasures, the American College of Medical Toxicology (ACMT) supports several strategies: (1) The use of expired atropine, diazepam, and pralidoxime auto-injectors and vials if non-expired drugs are unavailable; and (2) Investigation, development, and identification of alternative countermeasures-commonly stocked drugs that are not approved for nerve agent poisoning but are in the same therapeutic class as approved drugs.

Development of small bisquaternary cholinesterase inhibitors as drugs for pre-treatment of nerve agent poisonings.

BackgroundIntoxication by nerve agents could be prevented by using small acetylcholinesterase inhibitors (eg, pyridostigmine) for potentially exposed personnel. However, the serious side effects of currently used drugs led to research of novel potent molecules for prophylaxis of organophosphorus intoxication.MethodsThe molecular design, molecular docking, chemical synthesis, in vitro methods (enzyme inhibition, cytotoxicity, and nicotinic receptors modulation), and in vivo methods (acute toxicity and prophylactic effect) were used to study bispyridinium, bisquinolinium, bisisoquinolinium, and pyridinium-quinolinium/isoquinolinium molecules presented in this study.ResultsThe studied molecules showed non-competitive inhibitory ability towards human acetylcholinesterase in vitro that was further confirmed by molecular modelling studies. Several compounds were selected for further studies. First, their cytotoxicity, nicotinic receptors modulation, and acute toxicity (lethal dose for 50% of laboratory animals [LD50]; mice and rats) were tested to evaluate their safety with promising results. Furthermore, their blood levels were measured to select the appropriate time for prophylactic administration. Finally, the protective ratio of selected compounds against soman-induced toxicity was determined when selected compounds were found similarly potent or only slightly better to standard pyridostigmine.ConclusionThe presented small bisquaternary molecules did not show overall benefit in prophylaxis of soman-induced in vivo toxicity.

Midazolam Efficacy Against Acute Hydrogen Sulfide-Induced Mortality and Neurotoxicity

Hydrogen sulfide (H2S) is a colorless, highly neurotoxic gas. It is not only an occupational and environmental hazard but also of concern to the Department of Homeland Security for potential nefarious use. Acute high-dose H2S exposure causes death, while survivors may develop neurological sequelae. Currently, there is no suitable antidote for treatment of acute H2S-induced neurotoxicity. Midazolam (MDZ), an anti-convulsant drug recommended for treatment of nerve agent intoxications, could also be of value in treating acute H2S intoxication. In this study, we tested the hypothesis that MDZ is effective in preventing/treating acute H2S-induced neurotoxicity. This proof-of-concept study had two objectives: to determine whether MDZ prevents/reduces H2S-induced mortality and to test whether MDZ prevents H2S-induced neurological sequelae. MDZ (4 mg/kg) was administered IM in mice, 5 min pre-exposure to a high concentration of H2S at 1000 ppm or 12 min post-exposure to 1000 ppm H2S followed by 30 min of continuous exposure. A separate experiment tested whether MDZ pre-treatment prevented neurological sequelae. Endpoints monitored included assessment of clinical signs, mortality, behavioral changes, and brain histopathological changes. MDZ significantly reduced H2S-induced lethality, seizures, knockdown, and behavioral deficits (p < 0.01). MDZ also significantly prevented H2S-induced neurological sequelae, including weight loss, behavior deficits, neuroinflammation, and histopathologic lesions (p < 0.01). Overall, our findings show that MDZ is a promising drug for reducing H2S-induced acute mortality, neurotoxicity, and neurological sequelae.

The biodistribution and pharmacokinetics of the oxime acetylcholinesterase reactivator RS194B in guinea pigs

Organophosphorus-based (OP) nerve agents represent some of the most toxic substances known to mankind. The current standard of care for exposure has changed very little in the past decades, and relies on a combination of atropine to block receptor activity and oxime-type acetylcholinesterase (AChE) reactivators to reverse the OP binding to AChE. Although these oximes can block the effects of nerve agents, their overall efficacy is reduced by their limited capacity to cross the blood-brain barrier (BBB). RS194B, a new oxime developed by Radic et al. (J. Biol. Chem., 2012) has shown promise for enhanced ability to cross the BBB. To fully assess the potential of this compound as an effective treatment for nerve agent poisoning, a comprehensive evaluation of its pharmacokinetic (PK) and biodistribution profiles was performed using both intravenous and intramuscular exposure routes. The ultra-sensitive technique of accelerator mass spectrometry was used to quantify the compound's PK profile, tissue distribution, and brain/plasma ratio at four dose concentrations in guinea pigs. PK analysis revealed a rapid distribution of the oxime with a plasma t1/2 of ∼1 h. Kidney and liver had the highest concentrations per gram of tissue followed by lung, spleen, heart and brain for all dose concentrations tested. The Cmax in the brain ranged between 0.03 and 0.18% of the administered dose, and the brain-to-plasma ratio ranged from 0.04 at the 10 mg/kg dose to 0.18 at the 200 mg/kg dose demonstrating dose dependent differences in brain and plasma concentrations. In vitro studies show that both passive diffusion and active transport contribute little to RS194B traversal of the BBB. These results indicate that biodistribution is widespread, but very low quantities accumulate in the guinea pig brain, indicating this compound may not be suitable as a centrally active reactivator.

A primer on nerve agents: what the emergency responder, anesthesiologist, and intensivist needs to know.

The purpose of this review article is to familiarize first responders, anesthesiologists, and intensivists with the medical management of patients exposed to nerve agents. This review is based on the current medical literature available to the general medical community. Nerve agents are some of the deadliest substances known to humanity. Though they kill primarily via muscle paralysis, which leads to respiratory arrest, these agents affect virtually every organ system in the body. Their primary mechanism of action is the body-wide inhibition of cholinesterases. This inhibition leads to the accumulation of acetylcholine, stimulating both nicotinic and muscarinic receptors. After decontamination, the primary treatment is with atropine to control muscarinic symptoms and with oximes to reactivate the cholinesterases and treat the nicotinic symptoms. Atropine doses can be much higher than conventionally used. Seizures are generally best treated with benzodiazepines. Patients with substantial exposure may require ventilatory and intensive care unit support for prolonged periods of time. While it is unlikely that most medical practitioners will ever encounter nerve agent poisoning, it is critical to be aware of the presenting symptoms and how best to treat patients exposed to these deadly agents. History has shown that rapid medical treatment can easily mean the difference between life and death for a patient in this situation.

Human butyrylcholinesterase efficacy against nerve agent exposure.

Acetylcholinesterase is vital for normal operation of many processes in the body. Following exposure to organophosphorus (OP) nerve agents, death can ensue without immediate medical intervention. Current therapies mitigate the cholinergic crisis caused by nerve agents but do not fully prevent long-term health concerns, for example, brain damage following seizures. Human butyrylcholinesterase (HuBChE) is a stoichiometric bioscavenger being investigated as an antidote for OP nerve agent poisoning. HuBChE sequesters OP nerve agent in the bloodstream preventing the nerve agent from reaching critical target organ systems. HuBChE was effective when used as both a pre-treatment and as a post-exposure therapy. HuBChE has potential for use in both military settings and to protect civilian first responders in situations where nerve agent usage is suspected. We reviewed various animal models studies evaluating the efficacy of HuBChE against nerve agent exposure, pursuant to its submission for approval under the FDA Animal Rule.

Lead Poisoning: Awareness in Medical and Non-Medical Population of Karachi

Lead is a heavy element, also termed as nerve poison. Lead interferes with a variety of body processes and is toxic to many organs and tissues, including the central nervous system. The purpose of this study is to evaluate awareness regarding lead poisoning, factors that cause lead poisoning, symptoms, effect on enzymes, treatment and preventive measure that can be adopted to reduce lead poisoning in our population. It is a descriptive cross sectional survey based study consisting of 300 individuals comprising of 100 medical professionals and 200 laypersons (100 from Literate and 100 from Illiterate Population). The study was carried out from different locations in Karachi and answers were recorded as open and close ended. Our study showed that 95% medical professionals, 53% Literate layperson whereas only 29% Illiterate layperson were aware about lead poisoning. 38% Literate, 27% Illiterate and 54% medical professional knew about the sources of lead poisoning. 82% medical professionals, 17% Literate laypersons were aware about pharmacological intervention and there was no awareness among Illiterate Population.

Time Course, Behavioral Safety, and Protective Efficacy of Centrally Active Reversible Acetylcholinesterase Inhibitors in Cynomolgus Macaques.

Galantamine hydrobromide and (-)huperzine A, centrally active reversible acetylcholinesterase inhibitors, are potentially superior to the current standard, pyridostigmine bromide, as a pretreatment for organophosphorus chemical warfare nerve agent intoxication. Galantamine, huperzine, and pyridostigmine were compared for time course of acetylcholinesterase inhibition in 12 cynomolgus macaques. Although both galantamine and huperzine shared a similar time course profile for acetylcholinesterase inhibition, huperzine was 88 times more potent than galantamine. The dose for 50% acetylcholinesterase inhibition (ID50) was 4.1ug/kg for huperzine, 362ug/kg for galantamine, and 30.9ug/kg for pyridostigmine. In a safety assessment, galantamine, huperzine, and pyridostigmine were examined using an operant time-estimation task. Huperzine and pyridostigmine were devoid of behavioral toxicity, whereas galantamine was behaviorally toxic at doses producing peak acetylcholinesterase inhibition of about 50% and higher. Following pretreatment with galantamine, huperzine or pyridostigmine, monkeys were challenged with the median lethal dose of soman at the time of peak acetylcholinesterase inhibition and evaluated for overt signs of soman toxicity (cholinergic crisis, convulsions). Both huperzine and galantamine were equally effective at preventing overt signs of soman toxicity, but neither drug was capable of preventing soman-induced neurobehavioral disruption. In contrast, three of four pyridostigmine-pretreated animals exposed to soman exhibited convulsions and required therapy. Full functional recovery required 3-16days. The degree of acetylcholinesterase inhibition was lower for pyridostigmine, but rates of recovery of acetylcholinesterase activity following soman challenge were comparable for all drug pretreatments. Huperzine may be the more promising centrally active reversible acetylcholinesterase inhibitor due to its greater potency and superior safety profile.

Organophosphate-Hydrolyzing Enzymes as First-Line of Defence Against Nerve Agent-Poisoning: Perspectives and the Road Ahead.

Nerve agents (NAs) are extremely neurotoxic synthetic organophosphate (OP) compounds exploited as weapons of mass destruction in terrorist attacks and chemical warfare. Considering the current world scenario, there is a persistent threat of NA-exposure to military personals and civilians. Various prophylactic and post-exposure treatments (such as atropine and oximes) available currently for NA-poisoning are inadequate and unsatisfactory and suffer from severe limitations. Hence, developing safe and effective treatment(s) against NA-poisoning is a critical necessity. With regards to counteracting NA-toxicity, the OP-hydrolyzing enzymes (OPHEs), which can hydrolyze and inactivate a variety of NAs, have emerged as promising candidates for the development of prophylactic therapy against NA-poisoning. However, there are many hurdles to be crossed before these enzymes can be brought to therapeutic use in humans. In this article, we have reviewed the various advancements in the field of development of OPHEs as prophylactic against NA-poisoning. The article majorly focuses on the toxic effects of NAs, various available therapies to counteract NA poisoning, the current status of OPHEs and attempts made to improve the various properties of these enzymes. Further, we have also briefly discussed about the prospective work that is needed to be undertaken for developing these OPHEs into those suitable for use in humans.

VX toxicity in the Göttingen minipig

The present experiments determined the intramuscular LD50 of VX in male Göttingen minipigs at two stages of development. In pubertal animals (115 days old), the LD50 of VX was indeterminate, but approximated 33.3μg/kg. However, in sexually mature animals (152 days old), the LD50 was estimated to be only 17.4μg/kg. Signs of nerve agent toxicity in the Göttingen minipig were similar to those described for other species, with some notable exceptions (such as urticaria and ejaculation). Latencies to the onset of sustained convulsions were inversely related to the administered dose of VX in both ages of minipigs. Additionally, actigraphy was used to quantify the presence of tremor and convulsions and, in some cases, was useful for precisely estimating time of death. The main finding indicates that in minipigs, as in other species, even relatively small differences in age can substantially alter the toxicity of nerve agents. Additionally, actigraphy can serve as a non-invasive method of characterizing the tremors and convulsions that often accompany nerve agent intoxication.

Malathion Madness

SESSION TITLE: Student/Resident Case Report Poster - Critical Care II SESSION TYPE: Student/Resident Case Report Poster PRESENTED ON: Tuesday, October 25, 2016 at 01:30 PM - 02:30 PM INTRODUCTION: Toxidromes make up a small but significant proportion of ICU admissions. Prompt recognition is important in order to treat the patient appropriately. Here we present a case of an inadvertent organophosphate intoxication due to extreme delusions. CASE PRESENTATION: A 45 year old male was found unconscious in his van surrounded by Pinesol, Malathion bug spray, and drug paraphernalia. He was confused with pinpoint pupils, copious secretions, incontinence, and sores on his face. His labs were remarkable for an elevated WBC, lactate and CK. He developed pulmonary edema and was intubated. Given his symptoms and the presence of Malathion in the van, organophosphate toxicity was suspected. Supportive measures including atropine and pralidoxime were given and he gradually improved. His labs later showed decreased RBC and plasma cholinesterase. Coincidentally, his girlfriend was also admitted with vomiting and diarrhea and was able to provide a history. The patient had a botfly removed from a sore on his face one year ago. Fearing larval infestation, he purchased Malathion from Craigslist, injected it into his sores, and covered them with crazy glue. He also heavily fumigated his van to kill any insects. DISCUSSION: Organophosphate toxicity is uncommon in the United States, and Malathion, a commonly used pesticide, is one of the safest organophosphates due to its selective toxicity profile. Dermal exposure to Malathion has a lower exposure threshold for adverse events than inhalation. Organophosphates irreversibly inhibit acetylcholinesterase, resulting in pooling of acetylcholine at the muscarinic and nicotinic receptors. Symptoms of cholinergic excess include diarrhea, urination, miosis, bronchorrhea, bradycardia, emesis, lacrimation, and salivation (DUMBELLS). Diagnosis is based around the toxidrome and treatment is supportive, including atropine to decrease bronchial secretions and pralidoxime for respiratory muscle weakness. In severe situations, patients can have delayed neuropathy, or suffer from Intermediate Syndrome which may reflect inadequate treatment. Most patients, however, improve once the toxin leaves the system. CONCLUSIONS: Organophosphate toxicity should be recognized quickly to initiate proper treatment. Due to its safe profile, Malathion toxicity is rare. In this case, because of his delusions, our patient was exposed to Malathion by dermal injection and inhalation. Anticholinergic medications including atropine and pralidoxime were used to treat the patient’s organophosphate toxicity. Reference #1: Eddleston M, Buckley NA, Eyer P, et al. Management of acute organophosphorus pesticide poisoning. Lancet. 2008; 371: 597-607. Reference #2: Hulse EJ, Davies JOJ, Simpson AJ, et al. Respiratory complications of organophosphorous nerve agent and insecticide poisoning. American Journal of Respiratory and Critical Care Medicine. 2014; 190 (12): 1342-54. Reference #3: King AM, Aaron CK. Organophosphate and carbamate poisoning. Emergency Medicine Clinic of North America. 2015; 33: 133-51. DISCLOSURE: The following authors have nothing to disclose: Nirmala Surapaneni, Brent Tatsuno, David Silberstein No Product/Research Disclosure Information

A Concept of a Probable Autoinjector for Bio-threat Agents

Chemical and biological weapons can be used during conflicts and by terrorists to injure or kill humans and animals. Chemical weapons contain toxic chemicals and biological weapons contain pathogenic organisms. With proper protective equipments and training, the lethal effects of chemical and biological warfare agents can be minimised. First aid kit is available that contain detection, decontamination and medical protection for chemical warfare agents including autoinjectors, for rapid administration and faster absorption of drugs. The autoinjectors are safe and available for life saving drugs like atropine sulphate and pralidoxime chloride (nerve agent poisoning), epinephrine (anaphylaxis), diazepam (seizures) and sumatriptan (migraine). For bio-threat agents doxycycline alone is available as a broad spectrum antibiotic in the first aid kit. Majority of the bacterial agents are gram negative and hence amikacin drug cartridge was developed for the existing autoinjector. The advantage of amikacin is its safety, stability, can be given prophylactically and supplemented with other antibiotics when medical attention arrives. The usability and tolerability of amikacin administered repeatedly through autoinjector was studied using various haematological, biochemical and oxidative stress parameters in animal models. The results are promising and as there is no antibiotic autoinjector available, amikacin autoinjector can be considered for bio-threat agents.

Midazolam-ketamine dual therapy stops cholinergic status epilepticus and reduces Morris water maze deficits.

Pharmacoresistance remains an unsolved therapeutic challenge in status epilepticus (SE) and in cholinergic SE induced by nerve agent intoxication. SE triggers a rapid internalization of synaptic γ-aminobutyric acid A (GABAA ) receptors and externalization of N-methyl-d-aspartate (NMDA) receptors that may explain the loss of potency of standard antiepileptic drugs (AEDs). We hypothesized that a drug combination aimed at correcting the consequences of receptor trafficking would reduce SE severity and its long-term consequences. A severe model of SE was induced in adult Sprague-Dawley rats with a high dose of lithium and pilocarpine. The GABAA receptor agonist midazolam, the NMDA receptor antagonist ketamine, and/or the AED valproate were injected 40 min after SE onset in combination or as monotherapy. Measures of SE severity were the primary outcome. Secondary outcomes were acute neuronal injury, spontaneous recurrent seizures (SRS), and Morris water maze (MWM) deficits. Midazolam-ketamine dual therapy was more efficient than double-dose midazolam or ketamine monotherapy or than valproate-midazolam or valproate-ketamine dual therapy in reducing several parameters of SE severity, suggesting a synergistic mechanism. In addition, midazolam-ketamine dual therapy reduced SE-induced acute neuronal injury, epileptogenesis, and MWM deficits. This study showed that a treatment aimed at correcting maladaptive GABAA receptor and NMDA receptor trafficking can stop SE and reduce its long-term consequences. Early midazolam-ketamine dual therapy may be superior to monotherapy in the treatment of benzodiazepine-refractory SE.

Analysis of nerve agent metabolites from nail clippings by liquid chromatography tandem mass spectrometry.

While several methods for the bioanalysis of nerve agents or their metabolites have been developed for the verification of nerve agent exposure, these methods are generally limited in the amount of time after an exposure that markers of exposure can be detected (due to rapid metabolism from biological matrices). In this study, a method for the analysis of nerve agent hydrolysis products from nail clippings was developed to allow evaluation of nails as a long-term repository of these markers. Pinacolyl methylphosphonic acid (PMPA) and isopropyl methylphosphonic acid (IMPA) were extracted from nail samples with N,N-dimethylformamide and subsequently analyzed by liquid chromatography-tandem mass spectrometry. Limits of detection for PMPA and IMPA were 0.3μg/kg and 7.5μg/kg and linear ranges were 0.75-300μg/kg and 30-1500μg/kg, respectively. Precision was within 10% and 8% for PMPA and IMPA, respectively, and accuracy was 100±12% for both analytes. The approach presented here is complementary to current methods for nerve agent exposure verification, and should allow for long-term determination of nerve agent poisoning.