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Gage M, Putra M, Gomez-Estrada C, Golden M, Wachter L, Gard M, Thippeswamy T. Differential Impact of Severity and Duration of Status Epilepticus, Medical Countermeasures, and a Disease-Modifier, Saracatinib, on Brain Regions in the Rat Diisopropylfluorophosphate Model. Front Cell Neurosci 2021; 15:772868. [PMID: 34720886 PMCID: PMC8555467 DOI: 10.3389/fncel.2021.772868] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 09/28/2021] [Indexed: 11/29/2022] Open
Abstract
Acute organophosphate (OP) toxicity poses a significant threat to both military and civilian personnel as it can lead to a variety of cholinergic symptoms including the development of status epilepticus (SE). Depending on its severity, SE can lead to a spectrum of neurological changes including neuroinflammation and neurodegeneration. In this study, we determined the impact of SE severity and duration on disease promoting parameters such as gliosis and neurodegeneration and the efficacy of a disease modifier, saracatinib (AZD0530), a Src/Fyn tyrosine kinase inhibitor. Animals were exposed to 4 mg/kg diisopropylfluorophosphate (DFP, s.c.) followed by medical countermeasures. We had five experimental groups: controls (no DFP), animals with no continuous convulsive seizures (CS), animals with ∼20-min continuous CS, 31-60-min continuous CS, and > 60-min continuous CS. These groups were then assessed for astrogliosis, microgliosis, and neurodegeneration 8 days after DFP exposure. The 31-60-min and > 60-min groups, but not ∼20-min group, had significantly upregulated gliosis and neurodegeneration in the hippocampus compared to controls. In the piriform cortex and amygdala, however, all three continuous CS groups had significant upregulation in both gliosis and neurodegeneration. In a separate cohort of animals that had ∼20 and > 60-min of continuous CS, we administered saracatinib for 7 days beginning three hours after DFP. There was bodyweight loss and mortality irrespective of the initial SE severity and duration. However, in survived animals, saracatinib prevented spontaneous recurrent seizures (SRS) during the first week in both severity groups. In the ∼20-min CS group, compared to the vehicle, saracatinib significantly reduced neurodegeneration in the piriform cortex and amygdala. There were no significant differences in the measured parameters between the naïve control and saracatinib on its own (without DFP) groups. Overall, this study demonstrates the differential effects of the initial SE severity and duration on the localization of gliosis and neurodegeneration. We have also demonstrated the disease-modifying potential of saracatinib. However, its’ dosing regimen should be optimized based on initial severity and duration of CS during SE to maximize therapeutic effects and minimize toxicity in the DFP model as well as in other OP models such as soman.
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Affiliation(s)
- Meghan Gage
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States.,Neuroscience Interdepartmental Program, Iowa State University, Ames, IA, United States
| | - Marson Putra
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States.,Neuroscience Interdepartmental Program, Iowa State University, Ames, IA, United States
| | - Crystal Gomez-Estrada
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Madison Golden
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Logan Wachter
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Megan Gard
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Thimmasettappa Thippeswamy
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, United States.,Neuroscience Interdepartmental Program, Iowa State University, Ames, IA, United States
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Rambabu L, Mohamed F, Dhanarisi J, Gawarammana I, Raubenheimer J, Mackenzie L, Roberts MS, Buckley N, Eddleston M. Acute phenthoate self-poisoning: a prospective case series. Clin Toxicol (Phila) 2021; 60:214-220. [PMID: 33960866 DOI: 10.1080/15563650.2021.1917596] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND The clinical characteristics following self-poisoning with organophosphorus (OP) insecticides differs according to the insecticide ingested. Phenthoate is a dimethoxy WHO Hazard Class II OP pesticide with limited literature on its clinical characteristics and outcome. We aimed to better understand its clinical characteristics by studying patients with phenthoate self-poisoning in Sri Lanka. METHODS We conducted a prospective cohort study of patients presenting with phenthoate self-poisoning to eight hospitals in Sri Lanka between 2002 and 2018. Clinical outcomes were recorded for each patient. Blood samples for measuring plasma phenthoate concentration, cholinesterase activity, and response to oximes were available for a very small number of patients recruited to a clinical trial. RESULTS Two hundred and ninety-two patients who ingested agricultural phenthoate formulations were included in the study. Median time to admission was 3.9 (IQR 2.4 - 6.8) h. Forty-two (14.4%) patients were intubated, mostly (30/37, 81%) within 24 h of ingestion (median time to intubation 7.2 [IQR 2.6-20.9] h). Median duration of intubation was 74.8 (IQR 26.8-232.5) h; the longest duration in a survivor was 592 h. Nineteen died (case fatality 6.5%, 95% CI 4.0-10.0); median time to death was 37 (IQR 16 - 101.7) h. Median plasma phenthoate concentration in patients with samples (n = 81) was 135 (IQR 62.7-356.5) ng/mL (0.42 µmol/mL [0.2 to 1.1 µmol/mL]). Five of six patients receiving pralidoxime chloride 2 g showed an initial increase in AChE and BuChE activity that was not sustained despite an infusion of pralidoxime. CONCLUSION Phenthoate self-poisoning has a 6.5% case fatality rate. Most patients who experience respiratory failure undergo early intubation; most deaths occurred among those patients who were intubated less than 24 h after ingestion. There was a non-sustained increase in cholinesterase activity with pralidoxime, but further studies are required to analyse the extent to which oximes are clinically effective in phenthoate self-poisoning.
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Affiliation(s)
- Lekaashree Rambabu
- National Health Service Tayside, Dundee, UK.,Edinburgh Medical School, The University of Edinburgh, Edinburgh, UK
| | - Fahim Mohamed
- South Asian Clinical Toxicology Research Collaboration, Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka.,Department of Pharmacy, Faculty of Allied Health Sciences, University of Peradeniya, Peradeniya, Sri Lanka
| | - Jeevan Dhanarisi
- South Asian Clinical Toxicology Research Collaboration, Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka
| | - Indika Gawarammana
- South Asian Clinical Toxicology Research Collaboration, Faculty of Medicine, University of Peradeniya, Peradeniya, Sri Lanka
| | - Jacques Raubenheimer
- Faculty of Medicine and Health, Discipline of Biomedical Informatics and Digital Health, Clinical Pharmacology and Toxicology Research Group, The University of Sydney, Sydney, Australia
| | - Lorraine Mackenzie
- Therapeutics Research Centre, Clinical and Health Sciences, University of South Australia, Adelaide, Australia.,Basil Hetzel Institute for Translational Research, The Queen Elizabeth Hospital, Woodville, Australia
| | - Michael S Roberts
- Therapeutics Research Centre, Clinical and Health Sciences, University of South Australia, Adelaide, Australia.,Therapeutics Research Centre, Diamantina Institute, Translational Research Institute, The University of Queensland, Brisbane, Australia
| | - Nicholas Buckley
- Clinical Pharmacology and Toxicology Research Group, Discipline of Pharmacology, University of Sydney, Sydney, Australia
| | - Michael Eddleston
- Pharmacology, Toxicology, & Therapeutics, University/BHF Centre for Cardiovascular Science, Edinburgh, UK.,Centre for Pesticide Suicide Prevention, University of Edinburgh, Edinburgh, UK
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