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Neurotoxicity evoked by organophosphates and available countermeasures. Arch Toxicol 2023; 97:39-72. [PMID: 36335468 DOI: 10.1007/s00204-022-03397-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 10/11/2022] [Indexed: 11/07/2022]
Abstract
Organophosphorus compounds (OP) are a constant problem, both in the military and in the civilian field, not only in the form of acute poisoning but also for their long-lasting consequences. No antidote has been found that satisfactorily protects against the toxic effects of organophosphates. Likewise, there is no universal cure to avert damage after poisoning. The key mechanism of organophosphate toxicity is the inhibition of acetylcholinesterase. The overstimulation of nicotinic or muscarinic receptors by accumulated acetylcholine on a synaptic cleft leads to activation of the glutamatergic system and the development of seizures. Further consequences include generation of reactive oxygen species (ROS), neuroinflammation, and the formation of various other neuropathologists. In this review, we present neuroprotection strategies which can slow down the secondary nerve cell damage and alleviate neurological and neuropsychiatric disturbance. In our opinion, there is no unequivocal approach to ensure neuroprotection, however, sooner the neurotoxicity pathway is targeted, the better the results which can be expected. It seems crucial to target the key propagation pathways, i.e., to block cholinergic and, foremostly, glutamatergic cascades. Currently, the privileged approach oriented to stimulating GABAAR by benzodiazepines is of limited efficacy, so that antagonizing the hyperactivity of the glutamatergic system could provide an even more efficacious approach for terminating OP-induced seizures and protecting the brain from permanent damage. Encouraging results have been reported for tezampanel, an antagonist of GluK1 kainate and AMPA receptors, especially in combination with caramiphen, an anticholinergic and anti-glutamatergic agent. On the other hand, targeting ROS by antioxidants cannot or already developed neuroinflammation does not seem to be very productive as other processes are also involved.
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Cornelissen AS, Garcia EE, Raulli RE, Laney J, Joosen MJA. A delayed treatment model for the evaluation of scopolamine for VX nerve agent intoxication. Toxicol Appl Pharmacol 2021; 427:115650. [PMID: 34273408 DOI: 10.1016/j.taap.2021.115650] [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: 04/04/2021] [Revised: 06/24/2021] [Accepted: 07/12/2021] [Indexed: 11/18/2022]
Abstract
Most research on medical countermeasures for nerve agent exposure assumes a military scenario, in which (autoinjector) treatment is envisaged to be available immediately. In a civilian setting however, treatment is delayed until arrival of first-aid responders. This may significantly affect treatment efficacy and the requirements for secondary intensive care. The aim of the current study was to develop a guinea pig model to evaluate the efficacy of delayed treatment following nerve agent exposure. We identified a trigger-to-treat based on a progressive stage of the toxidrome following VX exposure, which was associated with the subsiding of clonic movements. This paradigm resulted in treatment consistently being administered between 15 and 25 min post-exposure. Using the model, we investigated the potential for the anticholinergic scopolamine to act as a delayed treatment either as a standalone treatment, or as an adjunct to delayed treatment with Standard of Care (SOC), containing atropine, 2-PAM, and midazolam. The study provides a framework for a small animal model for evaluating the efficacy of treatment administered at a specific stage of the toxidrome, when immediate treatment is absent. As an adjunct, scopolamine treatment did not result in improved survival, but did show a beneficial effect on recovery, in terms of general posture. As a standalone treatment, scopolamine showed a significant, dose-responsive, beneficial effect on survival and recovery. These promising results warrant additional studies to investigate which observed physiological improvements are relevant for the recovery process and residual injury.
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Affiliation(s)
- Alex S Cornelissen
- TNO Defence, Safety and Security, CBRN Protection, Rijswijk, the Netherlands.
| | - Efrain E Garcia
- Biomedical Advanced Research and Development Authority (BARDA), Assistant Secretary for Preparedness and Response (ASPR), Department of Health and Human Services (HHS), United States
| | - Robert E Raulli
- Biomedical Advanced Research and Development Authority (BARDA), Assistant Secretary for Preparedness and Response (ASPR), Department of Health and Human Services (HHS), United States
| | - Judith Laney
- Biomedical Advanced Research and Development Authority (BARDA), Assistant Secretary for Preparedness and Response (ASPR), Department of Health and Human Services (HHS), United States
| | - Marloes J A Joosen
- TNO Defence, Safety and Security, CBRN Protection, Rijswijk, the Netherlands
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Goldsmith M, Ashani Y, Margalit R, Nyska A, Mirelman D, Tawfik DS. A new post-intoxication treatment of paraoxon and parathion poisonings using an evolved PON1 variant and recombinant GOT1. Chem Biol Interact 2016; 259:242-251. [DOI: 10.1016/j.cbi.2016.05.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 05/04/2016] [Accepted: 05/25/2016] [Indexed: 10/21/2022]
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Reji KK, Mathew V, Zachariah A, Patil AKB, Hansdak SG, Ralph R, Peter JV. Extrapyramidal effects of acute organophosphate poisoning. Clin Toxicol (Phila) 2016; 54:259-65. [PMID: 26735571 DOI: 10.3109/15563650.2015.1126841] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND There is limited information on extrapyramidal symptoms in acute organophosphate (OP) poisoning. We describe the course and outcome of severely poisoned patients who develop extrapyramidal manifestations. METHODS In this prospective observational study, spanning 8 months (Apr-Nov 2013) adult patients (>18 years) admitted with OP poisoning were enrolled. Patients on anti-psychotic therapy, those refusing consent or presenting with co-ingestions were excluded. Treatment included atropine and supportive care (e.g. ventilation and inotropes as indicated); oximes were not administered. The presence of rigidity, tremors, dystonia and chorea were assessed daily till discharge using modifications of the Unified Parkinson's Disease rating scale and the Tremor rating scale. The presence of extrapyramidal manifestations was correlated with length of ventilation and hospital stay and mortality. RESULTS Of the 77 patients admitted with OP poisoning, 32 were enrolled; 17 (53.1%) developed extrapyramidal manifestations which included rigidity (94.1%), tremors (58.8%) and dystonia (58.8%). None developed chorea. The median (inter-quartile range) time of symptom onset was 8 (5-11) days; extrapyramidal features resolved in 11 (6-17) days. The median duration of intensive care stay in patients not developing extrapyramidal symptoms was 6 (2-8) days, indicating that most of these patients had recovered even before symptom onset in patients who developed extrapyramidal manifestations. Overall, 27/32 (84%) were ventilated. Hospital mortality was 6.25% (2/32). When compared with patients not developing extrapyramidal signs, those with extrapyramidal manifestations had significantly prolonged ventilation (5 versus 16 median days; p = 0.001) and hospitalization (8 versus 21 days; p < 0.001), reduced ventilator-free days (23 versus 12 days; p = 0.023) and increased infections (p = 0.03). The need for ventilation and mortality were not significantly different (p > 0.6). Extrapyramidal symptoms were not observed in non-OP poisoned patients with prolonged ICU stay. CONCLUSION In this small series of acute OP poisoning, extrapyramidal manifestations were common after 1 week of intensive care but self-limiting. They are significantly associated with longer duration of ventilation and hospital stay.
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Affiliation(s)
- Kent K Reji
- a Department of Neurology , Christian Medical College , Vellore , Tamil Nadu , India
| | - Vivek Mathew
- a Department of Neurology , Christian Medical College , Vellore , Tamil Nadu , India
| | - Anand Zachariah
- b Department of Medicine , Christian Medical College , Vellore , Tamil Nadu , India
| | - Anil Kumar B Patil
- a Department of Neurology , Christian Medical College , Vellore , Tamil Nadu , India
| | | | - Ravikar Ralph
- b Department of Medicine , Christian Medical College , Vellore , Tamil Nadu , India
| | - John Victor Peter
- c Medical Intensive Care Unit , Christian Medical College , Vellore , Tamil Nadu , India
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Eddleston M, Chowdhury FR. Pharmacological treatment of organophosphorus insecticide poisoning: the old and the (possible) new. Br J Clin Pharmacol 2015; 81:462-70. [PMID: 26366467 DOI: 10.1111/bcp.12784] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 09/09/2015] [Accepted: 09/11/2015] [Indexed: 01/31/2023] Open
Abstract
Despite being a major clinical and public health problem across the developing world, responsible for at least 5 million deaths over the last three decades, the clinical care of patients with organophosphorus (OP) insecticide poisoning has little improved over the last six decades. We are still using the same two antidotes - atropine and oximes - that first came into clinical use in the late 1950s. Clinical research in South Asia has shown how improved regimens of atropine can prevent deaths. However, we are still unsure about which patients are most likely to benefit from the use of oximes. Supplemental antidotes, such as magnesium, clonidine and sodium bicarbonate, have all been proposed and studied in small trials without production of definitive answers. Novel antidotes such as nicotinic receptor antagonists, beta-adrenergic agonists and lipid emulsions are being studied in large animal models and in pilot clinical trials. Hopefully, one or more of these affordable and already licensed antidotes will find their place in routine clinical care. However, the large number of chemically diverse OP insecticides, the varied poisoning they produce and their varied response to treatment might ultimately make it difficult to determine definitively whether these antidotes are truly effective. In addition, the toxicity of the varied solvents and surfactants formulated with the OP active ingredients complicates both treatment and studies. It is possible that the only effective way to reduce deaths from OP insecticide poisoning will be a steady reduction in their agricultural use worldwide.
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Affiliation(s)
- Michael Eddleston
- Pharmacology, Toxicology, & Therapeutics, University of Edinburgh, Edinburgh, UK.,National Poisons Information Service - Edinburgh, Royal Infirmary of Edinburgh, Edinburgh, UK
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Peter JV, Sudarsan TI, Moran JL. Clinical features of organophosphate poisoning: A review of different classification systems and approaches. Indian J Crit Care Med 2014; 18:735-45. [PMID: 25425841 PMCID: PMC4238091 DOI: 10.4103/0972-5229.144017] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
PURPOSE The typical toxidrome in organophosphate (OP) poisoning comprises of the Salivation, Lacrimation, Urination, Defecation, Gastric cramps, Emesis (SLUDGE) symptoms. However, several other manifestations are described. We review the spectrum of symptoms and signs in OP poisoning as well as the different approaches to clinical features in these patients. MATERIALS AND METHODS Articles were obtained by electronic search of PubMed(®) between 1966 and April 2014 using the search terms organophosphorus compounds or phosphoric acid esters AND poison or poisoning AND manifestations. RESULTS Of the 5026 articles on OP poisoning, 2584 articles pertained to human poisoning; 452 articles focusing on clinical manifestations in human OP poisoning were retrieved for detailed evaluation. In addition to the traditional approach of symptoms and signs of OP poisoning as peripheral (muscarinic, nicotinic) and central nervous system receptor stimulation, symptoms were alternatively approached using a time-based classification. In this, symptom onset was categorized as acute (within 24-h), delayed (24-h to 2-week) or late (beyond 2-week). Although most symptoms occur with minutes or hours following acute exposure, delayed onset symptoms occurring after a period of minimal or mild symptoms, may impact treatment and timing of the discharge following acute exposure. Symptoms and signs were also viewed as an organ specific as cardiovascular, respiratory or neurological manifestations. An organ specific approach enables focused management of individual organ dysfunction that may vary with different OP compounds. CONCLUSIONS Different approaches to the symptoms and signs in OP poisoning may better our understanding of the underlying mechanism that in turn may assist with the management of acutely poisoned patients.
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Affiliation(s)
- John Victor Peter
- Department of Medical Intensive Care, Christian Medical College and Hospital, Vellore, Tamil Nadu, India
| | - Thomas Isiah Sudarsan
- Department of Medical Intensive Care, Christian Medical College and Hospital, Vellore, Tamil Nadu, India
| | - John L Moran
- Department of Intensive Care Medicine, The Queen Elizabeth Hospital, Woodville, South Australia 5011, Australia
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Kaur S, Singh S, Chahal KS, Prakash A. Potential pharmacological strategies for the improved treatment of organophosphate-induced neurotoxicity. Can J Physiol Pharmacol 2014; 92:893-911. [DOI: 10.1139/cjpp-2014-0113] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Organophosphates (OP) are highly toxic compounds that cause cholinergic neuronal excitotoxicity and dysfunction by irreversible inhibition of acetylcholinesterase, resulting in delayed brain damage. This delayed secondary neuronal destruction, which arises primarily in the cholinergic areas of the brain that contain dense accumulations of cholinergic neurons and the majority of cholinergic projection, could be largely responsible for persistent profound neuropsychiatric and neurological impairments such as memory, cognitive, mental, emotional, motor, and sensory deficits in the victims of OP poisoning. The therapeutic strategies for reducing neuronal brain damage must adopt a multifunctional approach to the various steps of brain deterioration: (i) standard treatment with atropine and related anticholinergic compounds; (ii) anti-excitotoxic therapies to prevent cerebral edema, blockage of calcium influx, inhibition of apoptosis, and allow for the control of seizure; (iii) neuroprotection by aid of antioxidants and N-methyl-d-aspartate (NMDA) antagonists (multifunctional drug therapy), to inhibit/limit the secondary neuronal damage; and (iv) therapies targeting chronic neuropsychiatric and neurological symptoms. These neuroprotective strategies may prevent secondary neuronal damage in both early and late stages of OP poisoning, and thus may be a beneficial approach to treating the neuropsychological and neuronal impairments resulting from OP toxicity.
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Affiliation(s)
- Shamsherjit Kaur
- Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India
- Punjab Technical University, Kapurthala 144601, Punjab, India
| | - Satinderpal Singh
- Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India
| | - Karan Singh Chahal
- Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India
| | - Atish Prakash
- Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India
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Moretto A, Colosio C. The role of pesticide exposure in the genesis of Parkinson's disease: Epidemiological studies and experimental data. Toxicology 2013; 307:24-34. [DOI: 10.1016/j.tox.2012.11.021] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Revised: 11/04/2012] [Accepted: 11/17/2012] [Indexed: 12/21/2022]
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Chen Y. Organophosphate-induced brain damage: mechanisms, neuropsychiatric and neurological consequences, and potential therapeutic strategies. Neurotoxicology 2012; 33:391-400. [PMID: 22498093 DOI: 10.1016/j.neuro.2012.03.011] [Citation(s) in RCA: 150] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 03/24/2012] [Accepted: 03/25/2012] [Indexed: 02/06/2023]
Abstract
Organophosphate (OP)-induced brain damage is defined as progressive damage to the brain, resulting from the cholinergic neuronal excitotoxicity and dysfunction induced by OP-induced irreversible AChE inhibition. This delayed secondary neuronal damage that occurs mainly in the cholinergic regions of the brain that contain dense accumulations of cholinergic neurons and the majority of cholinergic projection, might be largely responsible for persistent profound neuropsychiatric and neurological impairments (memory, cognitive, mental, emotional, motor and sensory deficits) in the victims of OP poisoning. Neuroprotective strategies for attenuating OP-induced brain damage should target different development stages of OP-induced brain damage, and may include but not limited to: (1) Antidote therapies with atropine and related efficient anticholinergic drugs; (2) Anti-excitotoxic therapies targeting attenuation of cerebral edema and inflammatory reaction, blockage of calcium influx, inhibition of apoptosis program, and the control of seizures; (3) Neuroprotective strategies using cytokines, antioxidants and NMDAR antagonists (a single drug or a combination of drugs) to slow down the process of secondary neuronal damage; and (4) Therapies targeting individual symptoms or clusters of chronic neuropsychiatric and neurological symptoms. These neuroprotective strategies may help limit or prevent secondary neuronal damage at the early stage of OP poisoning and attenuate the subsequent neuropsychiatric and neurological impairments, thus reducing the long-term disability caused by exposure to OPs.
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Affiliation(s)
- Yun Chen
- BrightstarTech, Inc., 23102 Meadow Mist Road, Clarksburg, MD 20871, USA.
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Perkins MW, Pierre Z, Rezk P, Song J, Oguntayo S, Morthole V, Sciuto AM, Doctor BP, Nambiar MP. Protective Effects of Aerosolized Scopolamine Against Soman-Induced Acute Respiratory Toxicity in Guinea Pigs. Int J Toxicol 2011; 30:639-49. [DOI: 10.1177/1091581811415874] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The protective efficacy of the antimuscarinic agent scopolamine was evaluated against soman (o-pinacolyl methylphosphonofluoridate [GD])-induced respiratory toxicity in guinea pigs. Anesthetized animals were exposed to GD (841 mg/m3) by microinstillation inhalation exposure and treated 30 seconds later with endotracheally aerosolized scopolamine (0.25 mg/kg) and allowed to recover for 24 hours. Treatment with scopolamine significantly increased survival and reduced clinical signs of toxicity and body weight loss in GD-exposed animals. Analysis of bronchoalveolar lavage (BAL) fluid showed normalization of GD-induced increased cell death, total cell count, and protein following scopolamine treatment. The BAL fluid acetylcholinesterase and butyrylcholinesterase levels were also increased by scopolamine treatment. Respiratory dynamics parameters were normalized at 4 and 24 hours post–GD exposure in scopolamine-treated animals. Lung histology showed that scopolamine treatment reduced bronchial epithelial and subepithelial inflammation and multifocal alveolar septal edema. These results suggest that aerosolized scopolamine considerably protects against GD-induced respiratory toxicity.
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Affiliation(s)
- Michael W. Perkins
- Medical/Analytical Toxicology, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, USA
| | - Zdenka Pierre
- Medical/Analytical Toxicology, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, USA
| | - Peter Rezk
- Medical/Analytical Toxicology, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, USA
| | - Jian Song
- Blast-Induced Neurotrauma Branch, Center for Military Psychiatry and Neurosciences, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Samuel Oguntayo
- Blast-Induced Neurotrauma Branch, Center for Military Psychiatry and Neurosciences, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Venee Morthole
- Department of Pathology, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Alfred M. Sciuto
- Medical/Analytical Toxicology, US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, USA
| | - Bhupendra P. Doctor
- Blast-Induced Neurotrauma Branch, Center for Military Psychiatry and Neurosciences, Walter Reed Army Institute of Research, Silver Spring, MD, USA
| | - Madhusoodana P. Nambiar
- Blast-Induced Neurotrauma Branch, Center for Military Psychiatry and Neurosciences, Walter Reed Army Institute of Research, Silver Spring, MD, USA
- Uniformed Services University of the Health Sciences, Bethesda, MD, USA
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Che MM, Chanda S, Song J, Doctor BP, Rezk PE, Sabnekar P, Perkins MW, Sciuto AM, Nambiar MP. Aerosolized scopolamine protects against microinstillation inhalation toxicity to sarin in guinea pigs. Toxicol Mech Methods 2011; 21:463-72. [DOI: 10.3109/15376516.2011.562258] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Abstract
Movement disorder emergencies include any movement disorder which evolves over hours to days, in which failure to appropriately diagnose and manage can result in patient morbidity or mortality. It is crucial that doctors recognize these emergencies with accuracy and speed by obtaining the proper history and by being familiar with the phenomenology of frequently encountered movements. These disorders will be discussed based on the most common associated involuntary movement, either parkinsonism, dystonia, chorea, tics or myoclonus, and, when available, review the workup and treatment options based on the current literature.
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Oboh OT, Lamango NS. Liver prenylated methylated protein methyl esterase is the same enzyme as Sus scrofa carboxylesterase. J Biochem Mol Toxicol 2008; 22:51-62. [PMID: 18273909 DOI: 10.1002/jbt.20214] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The C-terminal --COOH of prenylated proteins is methylated to --COOCH3. The --COOCH3 ester forms are hydrolyzed by prenylated methylated protein methyl esterase (PMPMEase) to the original acid forms. This is the only reversible step of the prenylation pathway. PMPMEase has not been purified and identified and is therefore understudied. Using a prenylated-L-cysteine methyl ester as substrate, PMPMEase was purified to apparent homogeneity from porcine liver supernatant. SDS-PAGE analysis revealed an apparent mass of 57 kDa. Proteomics analyses identified 17 peptides (242 amino acids). A Mascot database search revealed these as portions of the Sus scrofa carboxylesterase, a 62-kDa serine hydrolase with the C-terminal HAEL endoplasmic reticulum-retention signal. It is at least 71% identical to such mammalian carboxylesterases as human carboxylesterase 1 with affinities toward hydrophobic substrates and known to activate prodrugs, metabolize active drugs, as well as detoxify various substances such as cocaine and food-derived esters. The purified enzyme hydrolyzed benzoyl-Gly-farnesyl-L-cysteine methyl ester and hydrocinamoyl farnesyl-L-cysteine methyl ester with Michaelis-Menten constant (K(m)) values of 33 +/- 4 and 25 +/- 4 microM and V(max) values of 4.51 +/- 0.28 and 6.80 +/- 0.51 nmol/min/mg of protein, respectively. It was inhibited by organophosphates, chloromethyl ketones, ebelactone A and B, and phenylmethylsulfonyl fluoride.
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Affiliation(s)
- Onovughode T Oboh
- College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Tallahassee, FL 32307, USA
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Abstract
Organophosphorus pesticide self-poisoning is an important clinical problem in rural regions of the developing world, and kills an estimated 200,000 people every year. Unintentional poisoning kills far fewer people but is a problem in places where highly toxic organophosphorus pesticides are available. Medical management is difficult, with case fatality generally more than 15%. We describe the limited evidence that can guide therapy and the factors that should be considered when designing further clinical studies. 50 years after first use, we still do not know how the core treatments--atropine, oximes, and diazepam--should best be given. Important constraints in the collection of useful data have included the late recognition of great variability in activity and action of the individual pesticides, and the care needed cholinesterase assays for results to be comparable between studies. However, consensus suggests that early resuscitation with atropine, oxygen, respiratory support, and fluids is needed to improve oxygen delivery to tissues. The role of oximes is not completely clear; they might benefit only patients poisoned by specific pesticides or patients with moderate poisoning. Small studies suggest benefit from new treatments such as magnesium sulphate, but much larger trials are needed. Gastric lavage could have a role but should only be undertaken once the patient is stable. Randomised controlled trials are underway in rural Asia to assess the effectiveness of these therapies. However, some organophosphorus pesticides might prove very difficult to treat with current therapies, such that bans on particular pesticides could be the only method to substantially reduce the case fatality after poisoning. Improved medical management of organophosphorus poisoning should result in a reduction in worldwide deaths from suicide.
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Affiliation(s)
- Michael Eddleston
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, England.
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Bar-Meir E, Schein O, Eisenkraft A, Rubinshtein R, Grubstein A, Militianu A, Glikson M. Guidelines for treating cardiac manifestations of organophosphates poisoning with special emphasis on long QT and Torsades De Pointes. Crit Rev Toxicol 2007; 37:279-85. [PMID: 17453935 DOI: 10.1080/10408440601177855] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Organophosphate poisoning may precipitate complex ventricular arrhythmias, a frequently overlooked and potentially lethal aspect of this condition. Acute effects consist of electrocardiographic ST-T segment changes and AV conduction disturbances of varying degrees, while long-lasting cardiac changes include QT prolongation, polymorphic tachycardia ("Torsades de Pointes"), and sudden cardiac death. Cardiac monitoring of organophosphate intoxicated patients for relatively long periods after the poisoning and early aggressive treatment of arrhythmias may be the clue to better survival. We present here a review of the literature with a focus on late cardiac arrhythmias (mainly "Torsades de pointes"), possible mechanisms, and treatment modalities, with special emphasis on postpoisoning monitoring for development of arrhythmias.
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Affiliation(s)
- Eran Bar-Meir
- CBRN Medical Branch, Medical Corps, Israel Defense Forces, Tel-Hashomer, Israel
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Abstract
There is well-founded concern that a chemical or radioactive agent will at some point be used as a weapon of terror. There are several antidotes that, if used correctly in a timely fashion, can help lessen the harm caused by these agents. This article is meant to introduce the clinician to several such agents, along with the antidotes useful in the management of exposure to these. It covers the indications, administration, and precautions for using these antidotes.
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Affiliation(s)
- David T Lawrence
- Blue Ridge Poison Center, Division of Medical Toxicology, Department of Emergency Medicine, University of Virginia, Charlottesville, VA 22908-0774, USA.
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