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Langston JL, Moffett MC, Pennington MR, Myers TM. Pharmacokinetics and pharmacodynamics of standard nerve agent medical countermeasures in Göttingen Minipigs. Toxicol Lett 2024; 397:103-116. [PMID: 38703967 DOI: 10.1016/j.toxlet.2024.04.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 04/18/2024] [Accepted: 04/26/2024] [Indexed: 05/06/2024]
Abstract
Animal research continues to serve a critical role in the testing and development of medical countermeasures. The Göttingen minipig, developed for laboratory research, may provide many benefits for addressing research questions within chemical defense. Targeted development of the Göttingen minipig model could reduce reliance upon non-human primates, and improve study design, statistical power, and throughput to advance medical countermeasures for regulatory approval and fielding. In this vein, we completed foundational pharmacokinetics and physiological safety studies of intramuscularly administered atropine sulfate, pralidoxime chloride (2-PAM), and diazepam across a broad range of doses (1-6 autoinjector equivalent) using adult male Göttingen minipigs (n=11; n=4-8/study) surgically implanted with vascular access ports and telemetric devices to monitor cardiovascular, respiratory, arterial pressure, and temperature signals. Pharmacokinetic data were orderly and the concentration maximum mirrored available human data at comparably scaled doses clearly for atropine, moderately for 2-PAM, and poorly for diazepam. Time to peak concentration approximated 2, 7, and 20 min for atropine, 2-PAM, and diazepam, respectively, and the elimination half-life of these drugs approximated 2 hr (atropine), 3 hr (2-PAM), and 8 hr (diazepam). Atropine sulfate dose-dependently increased the magnitude and duration of tachycardia and decreased the PR and ST intervals (consistent with findings obtained from other species). Mild hypothermia was observed at the highest diazepam dose. Göttingen minipigs appear to provide a ready and appropriate large animal alternative to non-human primates, and further development and evaluation of novel nerve agent medical countermeasures and treatment strategies in this model are justified.
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Affiliation(s)
- Jeffrey L Langston
- United States Army Medical Research Institute of Chemical Defense, Medical Toxicology Research Division, Pharmaceutical Sciences Department, Aberdeen Proving Ground, MD 21010-5400, USA
| | - Mark C Moffett
- United States Army Medical Research Institute of Chemical Defense, Medical Toxicology Research Division, Pharmaceutical Sciences Department, Aberdeen Proving Ground, MD 21010-5400, USA
| | - M Ross Pennington
- United States Army Medical Research Institute of Chemical Defense, Medical Toxicology Research Division, Pharmaceutical Sciences Department, Aberdeen Proving Ground, MD 21010-5400, USA
| | - Todd M Myers
- United States Army Medical Research Institute of Chemical Defense, Medical Toxicology Research Division, Pharmaceutical Sciences Department, Aberdeen Proving Ground, MD 21010-5400, USA.
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2
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Goulay R, Fémy F, Nervo A, Valentino S, Madi M, Joly AL, Servonnet A, Nachon F, Reymond C, Jaffré N. Baseline physiological data from anesthetized pigs in a VX intoxication model. Toxicol Lett 2024; 397:117-128. [PMID: 38768837 DOI: 10.1016/j.toxlet.2024.05.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 05/10/2024] [Accepted: 05/17/2024] [Indexed: 05/22/2024]
Abstract
Over the past fifty years, swine models have been used for organophosphorus intoxication studies. Among these studies and others on the swine model in general, some physiological data, especially cholinesterase activity highly impacted by organophosphorus compounds like nerve agent VX, still need to be completed. To support and compare our model to others, we have published the experimental protocol, the physiological values of 31 juvenile anesthetized pigs, and the 6 h-follow-up of six supplementary anesthetized control animals and 7 VX-intoxicated pigs. We reported hemodynamics and respiratory parameters, blood levels in several biochemical parameters, blood gas, and complete blood count and compared them to the literature. We also focused on tissue and blood cholinesterase activities and detailed them for acetylcholinesterase and butyrylcholinesterase. After establishing a broad physiological data set consistent with the literature, we reported several cardio-respiratory parameters that seem more affected by an organophosphate intoxication, like heart rate, arterial blood pressure, cardiac output, and respiratory rate. Within the blood, oxygen saturation (SpO2), lactatemia, base excess, and glycemia can also be measured and associated with the other parameters to evaluate the life-threatening status. This swine model is currently used to develop and evaluate medical countermeasures against organophosphate nerve agent intoxications.
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Affiliation(s)
- R Goulay
- Department of Toxicology and Chemical Risks, French Armed Forces Biomedical Research Institute, Brétigny Sur Orge, France
| | - F Fémy
- Department of Toxicology and Chemical Risks, French Armed Forces Biomedical Research Institute, Brétigny Sur Orge, France; Departments of Emergency, Georges Pompidou European Hospital, Assistance Publique - Hôpitaux de Paris, France
| | - A Nervo
- Department of Toxicology and Chemical Risks, French Armed Forces Biomedical Research Institute, Brétigny Sur Orge, France
| | - S Valentino
- Department of Toxicology and Chemical Risks, French Armed Forces Biomedical Research Institute, Brétigny Sur Orge, France
| | - M Madi
- Department of Toxicology and Chemical Risks, French Armed Forces Biomedical Research Institute, Brétigny Sur Orge, France
| | - A-L Joly
- Department of Toxicology and Chemical Risks, French Armed Forces Biomedical Research Institute, Brétigny Sur Orge, France
| | - A Servonnet
- Department of Toxicology and Chemical Risks, French Armed Forces Biomedical Research Institute, Brétigny Sur Orge, France
| | - F Nachon
- Department of Toxicology and Chemical Risks, French Armed Forces Biomedical Research Institute, Brétigny Sur Orge, France
| | - C Reymond
- Department of Toxicology and Chemical Risks, French Armed Forces Biomedical Research Institute, Brétigny Sur Orge, France
| | - N Jaffré
- Department of Toxicology and Chemical Risks, French Armed Forces Biomedical Research Institute, Brétigny Sur Orge, France.
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Saya L, Ratandeep, Arya B, Rastogi K, Verma M, Rani S, Sahu PK, Singh MR, Singh WR, Hooda S. Recent advances in sensing toxic nerve agents through DMMP model simulant using diverse nanomaterials-based chemical sensors. Talanta 2024; 272:125785. [PMID: 38394750 DOI: 10.1016/j.talanta.2024.125785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Revised: 02/08/2024] [Accepted: 02/12/2024] [Indexed: 02/25/2024]
Abstract
Recent terrorist assaults have demonstrated the need for the exploration and design of sustainable and stable chemical sensors with quick reaction times combined with great sensitivity. Among several classes of chemical warfare agents, nerve agents have been proven to be the most hazardous. Even short-term exposure to them can result in severe toxic effects. Human beings inadvertently face the after-effects of these chemicals even several years after these chemicals were used. Due to the extreme toxicity and difficulty in handling, dimethyl methylphosphonate (DMMP), a simulant of nerve agents with much lesser toxicity, is frequently used in laboratories as a substitute. Having a chemical structure almost identical to those of nerve agents, DMMP can mimic the properties of nerve agents. Through this paper, authors have attempted to introduce the evolution of several chemical sensors used to detect DMMP in recent years, including field-effect transistors, chemicapacitors, chemiresistors, and mass-sensitive sensors. A detailed discussion of the role of nanomaterials as chemical sensors in the detection of DMMP has been the main focus of the work through a comprehensive overview of the research on gas sensors that have been reported making use of the properties of a wide range of nanomaterials.
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Affiliation(s)
- Laishram Saya
- Department of Chemistry, Sri Venkateswara College (University of Delhi), Dhaula Kuan, New Delhi 110021, India; Department of Chemistry, Manipur University, Canchipur, Imphal 795003, Manipur, India; Polymer Research Laboratory, Department of Chemistry, Acharya Narendra Dev College (University of Delhi), Govindpuri, Kalkaji, New Delhi, 110019, India.
| | - Ratandeep
- School of Chemical Sciences and Advanced Materials Research Center, Indian Institute of Technology Mandi, Kamand, Mandi 175075, Himachal Pradesh, India
| | - Bipasa Arya
- Polymer Research Laboratory, Department of Chemistry, Acharya Narendra Dev College (University of Delhi), Govindpuri, Kalkaji, New Delhi, 110019, India
| | - Kanjika Rastogi
- Polymer Research Laboratory, Department of Chemistry, Acharya Narendra Dev College (University of Delhi), Govindpuri, Kalkaji, New Delhi, 110019, India
| | - Manisha Verma
- Department of Physics, Acharya Narendra Dev College, (University of Delhi), Govindpuri, Kalkaji, New Delhi, 110019, India
| | - Sanjeeta Rani
- Department of Physics, Acharya Narendra Dev College, (University of Delhi), Govindpuri, Kalkaji, New Delhi, 110019, India
| | - Prasanta Kumar Sahu
- Department of Chemistry, Shivaji College, (University of Delhi), Raja Garden, New Delhi, 110027, India
| | - M Ramananda Singh
- Department of Chemistry, Kirorimal College, (University of Delhi), Delhi, 110007, India
| | - W Rameshwor Singh
- Department of Chemistry, Manipur University, Canchipur, Imphal 795003, Manipur, India.
| | - Sunita Hooda
- Polymer Research Laboratory, Department of Chemistry, Acharya Narendra Dev College (University of Delhi), Govindpuri, Kalkaji, New Delhi, 110019, India.
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Aitken AV, Minassa VS, Batista TJ, Oliveira JKDS, Sant'Anna KDO, Felippe ISA, Paton JFR, Coitinho JB, Bissoli NS, Sampaio KN. Acute poisoning by chlorpyrifos differentially impacts survival and cardiorespiratory function in normotensive and hypertensive rats. Chem Biol Interact 2024; 387:110821. [PMID: 38042398 DOI: 10.1016/j.cbi.2023.110821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 11/17/2023] [Accepted: 11/27/2023] [Indexed: 12/04/2023]
Abstract
Hypertension is the most important and well-known risk factor for cardiovascular disease (CVD). Recently, acute organophosphate (OP) poisoning has also been pointed as a CVD risk factor. Despite this evidence, no studies have contrasted the acute toxicosis and cardiovascular (CV) effects of OP poisoning under conditions of normotension and hypertension. In this work, adult male normotensive Wistar and Spontaneously Hypertensive rats (SHR) were intraperitoneally injected with saline or chlorpyrifos (CPF), an OP compound, monitored for acute toxicosis signs and 24-h survival. After poisoning, blood pressure, heart rate and ventilation were recorded, the Bezold-Jarisch Reflex (BJR), the Chemoreflex (CR) were chemically activated, as well as the cardiac autonomic tone (AUT) was assessed. Erythrocyte and brainstem acetylcholinesterase and plasmatic butyrylcholinesterase (BuChE) activities were measured as well as lipid peroxidation, advanced oxidation protein products (AOPP), nitrite/nitrate levels, expression of catalase, TNFα and angiotensin-I converting enzyme (ACE-1) within the brainstem. CPF induced a much more pronounced acute toxicosis and 33 % lethality in SHR. CPF poisoning impaired ventilation in SHR, the BJR reflex responses in Wistar rats, and the chemoreflex tachypneic response in both strains. CPF inhibited activity of cholinesterases in both strains, increased AOPP and nitrite/nitrate levels and expression of TNFα and ACE-1 in the brainstem of Wistar rats. Interestingly, SHR presented a reduced intrinsic BuChE activity, an important bioscavenger. Our findings show that, CPF at sublethal doses in normotensive rats lead to lethality and much more pronounced acute toxicity signs in the SHR. We also showed that cardiorespiratory reflexes were differentially impacted after CPF poisoning in both strains and that the cardiorespiratory disfunction seems to be associated with interference in cholinergic transmission, oxidative stress and inflammation. These results points to an increased susceptibility to acute toxicosis in hypertension, which may impose a significant risk to vulnerable populations.
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Affiliation(s)
- Andrew Vieira Aitken
- Postgraduate Program in Pharmaceutical Sciences, Department of Pharmaceutical Sciences, Federal University of Espírito Santo, Vitória, ES, Brazil; Department of Anatomy, Physiology, and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL, 36849, USA
| | - Vítor Sampaio Minassa
- Postgraduate Program in Pharmaceutical Sciences, Department of Pharmaceutical Sciences, Federal University of Espírito Santo, Vitória, ES, Brazil; Postgraduate Program in Physiological Sciences, Department of Physiology, Federal University of Espírito Santo, Vitória, ES, Brazil
| | - Thatiany Jardim Batista
- Postgraduate Program in Physiological Sciences, Department of Physiology, Federal University of Espírito Santo, Vitória, ES, Brazil
| | - Janne Ketly da Silva Oliveira
- Postgraduate Program in Pharmaceutical Sciences, Department of Pharmaceutical Sciences, Federal University of Espírito Santo, Vitória, ES, Brazil
| | - Karoline de Oliveira Sant'Anna
- Postgraduate Program in Pharmaceutical Sciences, Department of Pharmaceutical Sciences, Federal University of Espírito Santo, Vitória, ES, Brazil
| | - Igor Simões Assunção Felippe
- The Centre for Heart Research - Manaaki Mānawa, Department of Physiology, Faculty of Health & Medical Sciences, University of Auckland, Grafton Campus, Auckland, 1023, New Zealand
| | - Julian Francis Richmond Paton
- The Centre for Heart Research - Manaaki Mānawa, Department of Physiology, Faculty of Health & Medical Sciences, University of Auckland, Grafton Campus, Auckland, 1023, New Zealand
| | - Juliana Barbosa Coitinho
- Postgraduate Program in Pharmaceutical Sciences, Department of Pharmaceutical Sciences, Federal University of Espírito Santo, Vitória, ES, Brazil; Postgraduate Program in Biochemistry, Department of Physiology, Federal University of Espírito Santo, Vitória, ES, Brazil
| | - Nazaré Souza Bissoli
- Postgraduate Program in Physiological Sciences, Department of Physiology, Federal University of Espírito Santo, Vitória, ES, Brazil
| | - Karla Nívea Sampaio
- Postgraduate Program in Pharmaceutical Sciences, Department of Pharmaceutical Sciences, Federal University of Espírito Santo, Vitória, ES, Brazil.
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M. Schopfer L, David E, Hinrichs SH, Lockridge O. Human butyrylcholinesterase in Cohn fraction IV-4 purified in a single chromatography step on Hupresin. PLoS One 2023; 18:e0280380. [PMID: 36638134 PMCID: PMC9838835 DOI: 10.1371/journal.pone.0280380] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 12/26/2022] [Indexed: 01/14/2023] Open
Abstract
Protection from the toxicity of nerve agents is achieved by pretreatment with human butyrylcholinesterase (BChE). Current methods for purifying large quantities of BChE from frozen Cohn fraction IV-4 produce 99% pure enzyme, but the yield is low (21%). Our goal was to simplify the purification procedure and increase the yield. Butyrylcholinesterase was extracted from frozen Cohn fraction IV-4 in 10 volumes of water pH 6. The filtered extract was pumped onto a Hupresin affinity column. The previously utilized anion exchange chromatography step was omitted. Solvent and detergent reagents used to inactivate lipid enveloped virus, bacteria and protozoa did not bind to Hupresin. BChE was eluted with 0.1 M tetramethylammonium bromide in 20 mM sodium phosphate pH 8.0. BChE protein was concentrated on a Pellicon tangential flow filtration system and demonstrated to be highly purified by mass spectrometry. A high pump rate produced protein aggregates, but a low pump rate caused minimal turbidity. Possible contamination by prekallikrein and prekallikrein activator was examined by LC-MS/MS and by a chromogenic substrate assay for kallikrein activity. Prekallikrein and kallikrein were not detected by mass spectrometry in the 99% pure BChE. The chromogenic assay indicated kallikrein activity was less than 9 mU/mL. This new, 1-step chromatography protocol on Hupresin increased the yield of butyrylcholinesterase by 200%. The new method significantly reduces production costs by optimizing yield of 99% pure butyrylcholinesterase.
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Affiliation(s)
- Lawrence M. Schopfer
- Eppley Institute, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | | | - Steven H. Hinrichs
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Oksana Lockridge
- Eppley Institute, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
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Identification of Body Size Determination Related Candidate Genes in Domestic Pig Using Genome-Wide Selection Signal Analysis. Animals (Basel) 2022; 12:ani12141839. [PMID: 35883386 PMCID: PMC9312078 DOI: 10.3390/ani12141839] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 07/13/2022] [Accepted: 07/18/2022] [Indexed: 01/03/2023] Open
Abstract
This study aimed to identify the genes related to the body size of pigs by conducting genome-wide selection analysis (GWSA). We performed a GWSA scan on 50 pigs belonging to four small-bodied pig populations (Diannan small-eared pig, Bama Xiang pig, Wuzhishan pig, and Jeju black pig from South Korea) and 124 large-bodied pigs. We used the genetic parameters of the pairwise fixation index (FST) and π ratio (case/control) to screen candidate genome regions and genes related to body size. The results revealed 47,339,509 high-quality SNPs obtained from 174 individuals, while 280 interacting candidate regions were obtained from the top 1% signal windows of both parameters, along with 187 genes (e.g., ADCK4, AMDHD2, ASPN, ASS1, and ATP6V0C). The results of the candidate gene (CG) annotation showed that a series of CGs (e.g., MSTN, LTBP4, PDPK1, PKMYT1, ASS1, and STAT6) was enriched into the gene ontology terms. Moreover, molecular pathways, such as the PI3K-Akt, HIF-1, and AMPK signaling pathways, were verified to be related to body development. Overall, we identified a series of key genes that may be closely related to the body size of pigs, further elucidating the heredity basis of body shape determination in pigs and providing a theoretical reference for molecular breeding.
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7
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Onder S, Schopfer LM, Jiang W, Tacal O, Lockridge O. Butyrylcholinesterase in SH-SY5Y human neuroblastoma cells. Neurotoxicology 2022; 90:1-9. [PMID: 35189179 PMCID: PMC9124689 DOI: 10.1016/j.neuro.2022.02.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/15/2022] [Accepted: 02/16/2022] [Indexed: 10/19/2022]
Abstract
Cultured SH-SY5Y human neuroblastoma cells are used in neurotoxicity assays. These cells express markers of the cholinergic and dopaminergic systems. Acetylcholinesterase (AChE) activity has been reported in these cells. Neurotoxic organophosphate compounds that inhibit AChE, also inhibit butyrylcholinesterase (BChE). We confirmed the presence of AChE in the cell lysate by activity assays, Western blot, and liquid chromatography-tandem mass spectrometry (LC-MS/MS) of immunopurified AChE. A nondenaturing gel stained for AChE activity identified the catalytically active AChE in SH-SY5Y cells as the unstable monomer. We also identified immature BChE in the cell lysate. The concentration of active BChE protein was similar to that of active AChE protein. The rate of substrate hydrolysis by AChE was 10-fold higher than substrate hydrolysis by BChE. The higher rate was due to the 10-fold higher specific activity of AChE over BChE (5000 units/mg for AChE; 500 units/mg for BChE). Neither cholinesterase was secreted. Tryptic peptides of immunopurified AChE and BChE were identified by LC-MS/MS on an Orbitrap Lumos Fusion mass spectrometer. The unfolded protein chaperone, binding immunoglobulin protein BiP/GRP78, was identified in the mass spectral data from all cholinesterase samples, suggesting that BiP was co-extracted with cholinesterase. This suggests that the cytoplasmic cholinesterases are immature forms of AChE and BChE that bind to BiP. It was concluded that SH-SY5Y cells express active AChE and active BChE, but the proteins do not mature to glycosylated tetramers.
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Lumley L, Du F, Marrero-Rosado B, Stone M, Keith ZM, Schultz C, Whitten K, Walker K, Acon-Chen C, Wright L, Shih TM. Soman-induced toxicity, cholinesterase inhibition and neuropathology in adult male Göttingen minipigs. Toxicol Rep 2021; 8:896-907. [PMID: 33996503 PMCID: PMC8095108 DOI: 10.1016/j.toxrep.2021.04.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/09/2021] [Accepted: 04/16/2021] [Indexed: 01/05/2023] Open
Abstract
Animal models are essential for evaluating the toxicity of chemical warfare nerve agents (CWNAs) to extrapolate to human risk and are necessary to evaluate the efficacy of medical countermeasures. The Göttingen minipig is increasingly used for toxicological studies because it has anatomical and physiological characteristics that are similar to those of humans. Our objective was to determine whether the minipig would be a useful large animal model to evaluate the toxic effects of soman (GD). We determined the intramuscular (IM) median lethal dose (LD50) of GD in adult male Göttingen minipigs using an up-and-down dosing method. In addition to lethality estimates, we characterized the observable signs of toxicity, blood and tissue cholinesterase (ChE) activity and brain pathology following GD exposure. The 24 h LD50 of GD was estimated to be 4.7 μg/kg, with 95 % confidence limits of 3.6 and 6.3 μg/kg. As anticipated, GD inhibited ChE activity in blood and several tissues. Neurohistopathological analysis showed neurodegeneration and neuroinflammation in survivors exposed to 4.7 μg/kg of GD, including in the primary visual cortex and various thalamic nuclei. These findings suggest that the minipig will be a useful large animal model for assessing drugs to mitigate neuropathological effects of exposure to CWNAs.
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Affiliation(s)
- Lucille Lumley
- U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, United States
| | - Fu Du
- FD NeuroTechnologies, Inc., Columbia, MD, United States
| | - Brenda Marrero-Rosado
- U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, United States
| | - Michael Stone
- U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, United States
| | - Zora-Maya Keith
- U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, United States
| | - Caroline Schultz
- U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, United States
| | - Kimberly Whitten
- U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, United States
| | - Katie Walker
- U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, United States
| | - Cindy Acon-Chen
- U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, United States
| | - Linnzi Wright
- U.S. Army Combat Capabilities Development Command Chemical Biological Center, Aberdeen Proving Ground, MD, United States
| | - Tsung-Ming Shih
- U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, United States
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A Thermophilic Bacterial Esterase for Scavenging Nerve Agents: A Kinetic, Biophysical and Structural Study. Molecules 2021; 26:molecules26030657. [PMID: 33513869 PMCID: PMC7865465 DOI: 10.3390/molecules26030657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/23/2021] [Accepted: 01/23/2021] [Indexed: 12/02/2022] Open
Abstract
Organophosphorous nerve agents (OPNA) pose an actual and major threat for both military and civilians alike, as an upsurge in their use has been observed in the recent years. Currently available treatments mitigate the effect of the nerve agents, and could be vastly improved by means of scavengers of the nerve agents. Consequently, efforts have been made over the years into investigating enzymes, also known as bioscavengers, which have the potential either to trap or hydrolyze these toxic compounds. We investigated the previously described esterase 2 from Thermogutta terrifontis (TtEst2) as a potential bioscavenger of nerve agents. As such, we assessed its potential against G-agents (tabun, sarin, and cyclosarin), VX, as well as the pesticide paraoxon. We report that TtEst2 is a good bioscavenger of paraoxon and G-agents, but is rather slow at scavenging VX. X-ray crystallography studies showed that TtEst2 forms an irreversible complex with the aforementioned agents, and allowed the identification of amino-acids, whose mutagenesis could lead to better scavenging properties for VX. In conjunction with its cheap production and purification processes, as well as a robust structural backbone, further engineering of TtEst2 could lead to a stopgap bioscavenger useful for in corpo scavenging or skin decontamination.
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10
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Rosenberg Y, Saxena A. Acetylcholinesterase inhibition resulting from exposure to inhaled OP can be prevented by pretreatment with BChE in both macaques and minipigs. Neuropharmacology 2020; 174:108150. [PMID: 32442543 PMCID: PMC7365266 DOI: 10.1016/j.neuropharm.2020.108150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 05/05/2020] [Accepted: 05/14/2020] [Indexed: 10/24/2022]
Abstract
More frequent and widespread nerve agent attacks highlight the need for efficacious pre- and post-exposure organophosphate (OP) counter-measures to protect military and civilian populations. Because of critical targeting of acetylcholinesterase (AChE) in the CNS by OPs, a pre-treatment candidate for preventing/reducing poisoning will be a broadly acting molecule that scavenges OPs in blood before they reach their physiological targets. Prophylactic human butyrylcholinesterase (HuBChE), the leading pretreatment candidate, has been shown to protect against multiple LD50's of nerve agents in rodents, macaques, and minipigs. This review describes the development of a HuBChE bioscavenger pretreatment from early proof-of-concept studies to pre-clinical studies with the native injectable enzyme and the development of aerosolized forms of recombinant enzyme, which can be delivered by inhalation nebulizer devices, to effect protection against inhaled OP nerve agents and insecticides. Early animal studies utilized parenteral exposure. However, lungs are the portal of entry for most volatile OP vapors and represent the major means of OP intoxication. In this regard, pretreat-ment with 7.5 mg/kg of HuBChE by IM injection protected minipigs against lethal sarin vapor and prevented AChE inhibition in the blood. This is similar to the five-day protection in macaques by an aerosolized rHuBChE using a nebulizer against aerosolized paraoxon (estimated to be an 8 mg/kg estimated human dose). Importantly, lethal inhaled doses of OP may be smaller relative to the same dose delivered by injection, thus reducing the protective HuBChE dose, while a combination of HuBChE and post-exposure oxime may prolong protection.
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Affiliation(s)
| | - Ashima Saxena
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD, 20910, USA
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11
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diTargiani RC, Belinskaya T, Tipparaju P, Lockridge O, Saxena A. Proline 285 is integral for the reactivation of organophosphate-inhibited human butyrylcholinesterase by 2-PAM. Chem Biol Interact 2020; 324:109092. [PMID: 32278739 DOI: 10.1016/j.cbi.2020.109092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/24/2020] [Accepted: 04/05/2020] [Indexed: 11/15/2022]
Abstract
Human butyrylcholinesterase (HuBChE) is a stoichiometric bioscavenger that protects from the toxicity of nerve agents. Non-human primates are suitable models for toxicity studies that cannot be performed in humans. We evaluated the biochemical properties of native macaque (MaBChE) tetramers, compared to recombinant MaBChE monomers, PEGylated recombinant MaBChE tetramers and monomers, and native HuBChE tetramers. Km and kcat values for butyrylthiocholine were independent of subunit assembly status. The Km for all forms of MaBChE was about 70 μM, compared to 13 μM for HuBChE. The kcat was about 100,000 min-1 for MaBChE and 30,000 min-1 for HuBChE. The reversible inhibitor ethopropazine had similar Ki values of 0.05 μM for all MaBChE forms and HuBChE. The bimolecular rate constant, ki, for inhibition by diisopropylfluorophosphate (DFP), an analog of sarin, was 2.2 to 2.5 × 107 M-1 min-1 for all MaBChE forms and for HuBChE. A major difference between MaBChE and HuBChE was the rate of reactivation by 2-PAM. The second order rate constant for reactivation of DFP-inhibited MaBChE by 2-PAM was 1.4 M-1 min-1, but was 380 fold faster for DFP-inhibited HuBChE (kr 531 M-1 min-1). The acyl pocket of MaBChE has Leu285 in place of Pro285 in HuBChE. The reactivation rate of DFP-inhibited HuBChE mutant P285L by 2-PAM was reduced 5.8-fold (kr 92 M-1 min-1) indicating that P285 determines whether 2-PAM binds in an orientation that favors release of diisopropylphosphate. DFP-inhibited MaBChE treated with 0.2 M 2-PAM recovered 10% of its original activity, whereas DFP-inhibited HuBChE recovered 80% activity. It was concluded that the biochemical properties of MaBChE are similar to those of HuBChE except for the reactivation of DFP-inhibited BChE.
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Affiliation(s)
- Robert C diTargiani
- Division of Bacterial and Rickettsial Diseases, Walter Reed Army Institute of Research, Silver Spring, MD 20910.
| | - Tatyana Belinskaya
- Division of Bacterial and Rickettsial Diseases, Walter Reed Army Institute of Research, Silver Spring, MD 20910.
| | - Prasanthi Tipparaju
- Division of Bacterial and Rickettsial Diseases, Walter Reed Army Institute of Research, Silver Spring, MD 20910.
| | - Oksana Lockridge
- Eppley Institute, University of Nebraska Medical Center, Omaha, NE 68198.
| | - Ashima Saxena
- Division of Bacterial and Rickettsial Diseases, Walter Reed Army Institute of Research, Silver Spring, MD 20910.
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Toker L, Silman I, Zeev-Ben-Mordehai T, Sussman JL, Schopfer LM, Lockridge O. Polyproline-rich peptides associated with Torpedo californica acetylcholinesterase tetramers. Chem Biol Interact 2020; 319:109007. [PMID: 32087110 DOI: 10.1016/j.cbi.2020.109007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 01/31/2020] [Accepted: 02/17/2020] [Indexed: 01/30/2023]
Abstract
Acetylcholinesterase (AChE) terminates cholinergic neurotransmission by hydrolyzing acetylcholine. The collagen-tailed AChE tetramer is a product of 2 genes, ACHE and ColQ. The AChE tetramer consists of 4 identical AChE subunits and one polyproline-rich peptide, whose function is to hold the 4 AChE subunits together. Our goal was to determine the amino acid sequence of the polyproline-rich peptide(s) in Torpedo californica AChE (TcAChE) tetramers to aid in the analysis of images that will be acquired by cryo-EM. Collagen-tailed AChE was solubilized from Torpedo californica electric organ, converted to 300 kDa tetramers by digestion with trypsin, and purified by affinity chromatography. Polyproline-rich peptides were released by denaturing the TcAChE tetramers in a boiling water bath, and reducing disulfide bonds with dithiothreitol. Carbamidomethylated peptides were separated from TcAChE protein on a spin filter before they were analyzed by liquid chromatography tandem mass spectrometry on a high resolution Orbitrap Fusion Lumos mass spectrometer. Of the 64 identified collagen-tail (ColQ) peptides, 60 were from the polyproline-rich region near the N-terminus of ColQ. The most abundant proline-rich peptides were SVNKCCLLTPPPPPMFPPPFFTETNILQE, at 40% of total mass-spectral signal intensity, and SVNKCCLLTPPPPPMFPPPFFTETNILQEVDLNNLPLEIKPTEPSCK, at 27% of total intensity. The high abundance of these 2 peptides makes them candidates for the principal form of the polyproline-rich peptide in the trypsin-treated TcAChE tetramers.
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Affiliation(s)
- Lilly Toker
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, 7610001, Israel.
| | - Israel Silman
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, 7610001, Israel.
| | - Tzviya Zeev-Ben-Mordehai
- Cryo-Electron Microscopy, Bijvoet Center for Biomolecular Research, Utrecht University, 3584, CH, Utrecht, the Netherlands.
| | - Joel L Sussman
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, 7610001, Israel.
| | - Lawrence M Schopfer
- Eppley Institute, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
| | - Oksana Lockridge
- Eppley Institute, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
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13
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Prophylactic potential of memantine against soman poisoning in rats. Toxicology 2019; 416:62-74. [DOI: 10.1016/j.tox.2019.01.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 01/15/2019] [Accepted: 01/18/2019] [Indexed: 11/19/2022]
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14
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Purification of recombinant human butyrylcholinesterase on Hupresin®. J Chromatogr B Analyt Technol Biomed Life Sci 2018; 1102-1103:109-115. [PMID: 30384187 DOI: 10.1016/j.jchromb.2018.10.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 10/21/2018] [Accepted: 10/24/2018] [Indexed: 12/16/2022]
Abstract
Affinity chromatography on procainamide-Sepharose has been an important step in the purification of butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) since its introduction in 1978. The procainamide affinity gel has limitations. In the present report a new affinity gel called Hupresin® was evaluated for its ability to purify truncated, recombinant human butyrylcholinesterase (rHuBChE) expressed in a stably transfected Chinese Hamster Ovary cell line. We present a detailed example of the purification of rHuBChE secreted into 3940 mL of serum-free culture medium. The starting material contained 13,163 units of BChE activity (20.9 mg). rHuBChE was purified to homogeneity in a single step by passage over 82 mL of Hupresin® eluted with 0.1 M tetramethylammonium bromide in 20 mM TrisCl pH 7.5. The fraction with the highest specific activity of 630 units/mg contained 11 mg of BChE. Hupresin® is superior to procainamide-Sepharose for purification of BChE, but is not suitable for purifying native AChE because Hupresin® binds AChE so tightly that AChE is not released with buffers, but is desorbed with denaturing solvents such as 50% acetonitrile or 1% trifluoroacetic acid. Procainamide-Sepharose will continue to be useful for purification of AChE.
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15
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Characterization of butyrylcholinesterase from porcine milk. Arch Biochem Biophys 2018; 652:38-49. [PMID: 29908755 DOI: 10.1016/j.abb.2018.06.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 06/08/2018] [Accepted: 06/11/2018] [Indexed: 12/22/2022]
Abstract
Human butyrylcholinesterase (HuBChE) is under development for use as a pretreatment antidote against nerve agent toxicity. Animals are used to evaluate the efficacy of HuBChE for protection against organophosphorus nerve agents. Pharmacokinetic studies of HuBChE in minipigs showed a mean residence time of 267 h, similar to the half-life of HuBChE in humans, suggesting a high degree of similarity between BChE from 2 sources. Our aim was to compare the biochemical properties of PoBChE purified from porcine milk to HuBChE purified from human plasma. PoBChE hydrolyzed acetylthiocholine slightly faster than butyrylthiocholine, but was sensitive to BChE-specific inhibitors. PoBChE was 50-fold less sensitive to inhibition by DFP than HuBChE and 5-fold slower to reactivate in the presence of 2-PAM. The amino acid sequence of PoBChE determined by liquid chromatography tandem mass spectrometry was 91% identical to HuBChE. Monoclonal antibodies 11D8, mAb2, and 3E8 (HAH 002) recognized both PoBChE and HuBChE. Assembly of 4 identical subunits into tetramers occurred by noncovalent interaction with polyproline-rich peptides in PoBChE as well as in HuBChE, though the set of polyproline-rich peptides in milk-derived PoBChE was different from the set in plasma-derived HuBChE tetramers. It was concluded that the esterase isolated from porcine milk is PoBChE.
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16
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Abstract
Originally, organophosphorus (OP) toxicology consisted of acetylcholinesterase inhibition by insecticides and chemical threat agents acting as phosphorylating agents for serine in the catalytic triad, but this is no longer the case. Other serine hydrolases can be secondary OP targets, depending on the OP structure, and include neuropathy target esterase, lipases, and endocannabinoid hydrolases. The major OP herbicides are glyphosate and glufosinate, which act in plants but not animals to block aromatic amino acid and glutamine biosynthesis, respectively, with safety for crops conferred by their expression of herbicide-tolerant targets and detoxifying enzymes from bacteria. OP fungicides, pharmaceuticals including calcium retention agents, industrial chemicals, and cytochrome P450 inhibitors act by multiple noncholinergic mechanisms, often with high potency and specificity. One type of OP-containing fire retardant forms a highly toxic bicyclophosphate γ-aminobutyric acid receptor antagonist upon combustion. Some OPs are teratogenic, mutagenic, or carcinogenic by known mechanisms that can be avoided as researchers expand knowledge of OP chemistry and toxicology for future developments in bioregulation.
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Affiliation(s)
- John E Casida
- Environmental Chemistry and Toxicology Laboratory, Department of Environmental Science, Policy, and Management, University of California, Berkeley, California 94720-3112;
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17
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Plant-expressed cocaine hydrolase variants of butyrylcholinesterase exhibit altered allosteric effects of cholinesterase activity and increased inhibitor sensitivity. Sci Rep 2017; 7:10419. [PMID: 28874829 PMCID: PMC5585256 DOI: 10.1038/s41598-017-10571-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 08/10/2017] [Indexed: 12/04/2022] Open
Abstract
Butyrylcholinesterase (BChE) is an enzyme with broad substrate and ligand specificities and may function as a generalized bioscavenger by binding and/or hydrolyzing various xenobiotic agents and toxicants, many of which target the central and peripheral nervous systems. Variants of BChE were rationally designed to increase the enzyme’s ability to hydrolyze the psychoactive enantiomer of cocaine. These variants were cloned, and then expressed using the magnICON transient expression system in plants and their enzymatic properties were investigated. In particular, we explored the effects that these site-directed mutations have over the enzyme kinetics with various substrates of BChE. We further compared the affinity of various anticholinesterases including organophosphorous nerve agents and pesticides toward these BChE variants relative to the wild type enzyme. In addition to serving as a therapy for cocaine addiction-related diseases, enhanced bioscavenging against other harmful agents could add to the practicality and versatility of the plant-derived recombinant enzyme as a multivalent therapeutic.
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18
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Reed BA, Sabourin CL, Lenz DE. Human butyrylcholinesterase efficacy against nerve agent exposure. J Biochem Mol Toxicol 2017; 31. [DOI: 10.1002/jbt.21886] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 11/23/2016] [Accepted: 11/28/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Beth A. Reed
- Battelle Memorial Institute; Columbus OH 43201-2693 USA
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Use of V agents and V-analogue compounds to probe the active site of atypical butyrylcholinesterase from Oryzias latipes. Chem Biol Interact 2016; 259:182-186. [PMID: 27000540 DOI: 10.1016/j.cbi.2016.03.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 03/03/2016] [Accepted: 03/15/2016] [Indexed: 11/22/2022]
Abstract
The atypical butyrylcholinesterase (aBuChE) from Oryzias latipes shares approximately 65% sequence similarity to both acetylcholinesterase and butyrylcholinesterase and was studied for its capacity to spontaneously reactivate following inhibition by organophosphorus nerve agents. Like other cholinesterases, aBuChE was inhibited by all G- and V-type nerve agents. Interestingly, aBuChE was able to undergo spontaneous reactivation after inhibition with VR (t1/2 = 5.5 ± 0.2 h). Mass spectrometry of aBuChE after VR inhibition confirmed the presence of a covalently bound adduct of the size expected for non-aged VR on the peptide containing the active site serine. To understand the effect of substrate volume on rates of reactivation, the capacity of aBuChE to bind and spontaneously reactivate after inhibition with five V-agent analogues was examined. No appreciable reactivation was detected for enzyme inhibited by V2 (VX with O-isopropyl on retained group), V4 (VX with N-diethyl leaving group termination), or V5 (VX with N-dimethyl leaving group termination). Minimal reactivation was detected with V1 (VX with O-propyl on retained group). Conversely, spontaneous reactivation was observed when aBuChE was inhibited by V3 (VX with O-isobutyl on retained group; t1/2 = 6.3 ± 0.4 h). The data suggest that the ability of aBuChE to spontaneously reactivate after inhibition by V-agent analogues is related to the structure of the retained group. These results provide structural information that may shed light on the design of improved small molecule reactivators of nerve agent-inhibited acetylcholinesterase or butyrylcholinesterase, and further suggest that re-engineering the active site of a cholinesterase could result in enzymes with clinically relevant rates of nerve agent hydrolysis.
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20
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Langston JL, Myers TM. VX toxicity in the Göttingen minipig. Toxicol Lett 2016; 264:12-19. [PMID: 27773723 DOI: 10.1016/j.toxlet.2016.10.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 09/20/2016] [Accepted: 10/19/2016] [Indexed: 11/18/2022]
Abstract
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.
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Affiliation(s)
- Jeffrey L Langston
- Analytical Toxicology Division, United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, USA
| | - Todd M Myers
- Analytical Toxicology Division, United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, USA.
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Myhrer T, Aas P. Pretreatment and prophylaxis against nerve agent poisoning: Are undesirable behavioral side effects unavoidable? Neurosci Biobehav Rev 2016; 71:657-670. [PMID: 27773692 DOI: 10.1016/j.neubiorev.2016.10.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 09/28/2016] [Accepted: 10/19/2016] [Indexed: 10/20/2022]
Abstract
The threat of chemical warfare agents like nerve agents requires life saving measures of medical pretreatment combined with treatment after exposure. Pretreatment (pyridostigmine) may cause some side effects in a small number of individuals. A comprehensive research on animals has been performed to clarify effects on behavior. The results from these studies are far from unambiguous, since pyridostigmine may produce adverse effects on behavior in animals in relatively high doses, but not in a consistent way. Other animal studies have examined the potential of drugs like physostigmine, galantamine, benactyzine, trihexyphenidyl, and procyclidine, but they all produce marked behavioral impairment at doses sufficient to contribute to protection against a convulsant dose of soman. Attempts have also been made to develop a combination of drugs capable of assuring full protection (prophylaxis) against nerve agents. However, common to all combinations is that they at anticonvulsant doses cause behavioral deficits. Therefore, the use of limited pretreatment doses may be performed without marked side effects followed by post-exposure therapy with a combination of drugs.
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Affiliation(s)
- Trond Myhrer
- Norwegian Defence Research Establishment (FFI), Protection and Societal Security Division, Kjeller, Norway
| | - Pål Aas
- Norwegian Defence Research Establishment (FFI), Protection and Societal Security Division, Kjeller, Norway.
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Rosenberg YJ, Fink JB. Creation of a protective pulmonary bioshield against inhaled organophosphates using an aerosolized bioscavenger. Ann N Y Acad Sci 2016; 1374:151-8. [PMID: 27371808 DOI: 10.1111/nyas.13106] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 04/18/2016] [Accepted: 04/22/2016] [Indexed: 01/15/2023]
Abstract
In addition to the global use of organophosphate (OP) pesticides for agriculture, OP nerve agents and pesticides have been employed on battlefields and by terrorists (e.g., a recent sarin attack in Syria). These occurrences highlight the need for an effective countermeasure against OP exposure. Human butyrylcholinesterase (HuBChE) is a leading candidate, but injection of the high doses required for protection present pharmacokinetic challenges. An aerosolized recombinant form (aer-rHuBChE) that can neutralize inhaled OPs at the portal of entry has been assessed for its efficacy in protecting macaques against respiratory toxicity following inhalation exposure to the pesticide paraoxon (aer-Px). While protection in macaques has been demonstrated using the MicroSprayer® delivery device, administration to humans will likely employ a vibrating mesh nebulizer (VMN). Compared to the 50-70% lung deposition achieved in adult humans with a VMN, deposition in macaques is <5%, an initial major obstacle to demonstrating protection. Such problems have been partly overcome by using a more efficient modified VMN and proportionally higher doses, which together generate an effective rHuBChE pulmonary bioshield and protect against high levels of inhaled Px.
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Affiliation(s)
| | - James B Fink
- Department of Respiratory Care, Georgia State, University, Atlanta, Georgia
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