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Murray KE, Ratliff WA, Delic V, Citron BA. Gulf War toxicant-induced reductions in dendritic arbors and spine densities of dentate granule cells are improved by treatment with a Nrf2 activator. Brain Res 2024; 1823:148682. [PMID: 37989436 DOI: 10.1016/j.brainres.2023.148682] [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: 09/01/2023] [Revised: 11/08/2023] [Accepted: 11/15/2023] [Indexed: 11/23/2023]
Abstract
Gulf War Illness (GWI) is a chronic multi-symptom disorder affecting approximately 30 % of Veterans deployed to the Persian Gulf from 1990 to 91. GWI encompasses a wide spectrum of symptoms which frequently include neurological problems such as learning and memory impairments, mood disorders, and an increased incidence of neurodegenerative disorders. Combined exposure to both reversible and irreversible acetylcholinesterase (AChE) inhibitors has been identified as a likely risk factor for GWI. It is possible that the exposures affected connectivity in the brain, and it was also unknown whether this could benefit from treatment. We assessed chronic changes in dendritic architecture in granule cells of the dentate gyrus following exposure to pyridostigmine bromide (PB, 0.7 mg/kg), chlorpyrifos (CPF, 12.5 mg/kg), and N,N-diethyl-m-toluamide (DEET, 7.5 mg/kg) in male C57Bl/6J mice. We also evaluated the therapeutic effects of dietary administration for eight weeks of 1 % tert-butylhydroquinone (tBHQ), a Nrf2 activator, on long-term neuronal morphology. We found that Gulf War toxicant exposure resulted in reduced dendritic length and branching as well as overall spine density in dentate granule cells at 14 weeks post-exposure and that these effects were ameliorated by treatment with tBHQ. These findings indicate that Gulf War toxicant exposure results in chronic changes to dentate granule cell morphology and that modulation of neuroprotective transcription factors such as Nrf2 may improve long-term neuronal health in the hippocampus.
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Affiliation(s)
- Kathleen E Murray
- Laboratory of Molecular Biology, Research & Development, Department of Veterans Affairs, VA New Jersey Health Care System, East Orange, NJ 07018, USA; School of Graduate Studies, Rutgers University, Newark, NJ 07103, USA
| | - Whitney A Ratliff
- Research & Development, Department of Veterans Affairs, Bay Pines VA Healthcare System, Bay Pines, FL 33744, USA
| | - Vedad Delic
- Laboratory of Molecular Biology, Research & Development, Department of Veterans Affairs, VA New Jersey Health Care System, East Orange, NJ 07018, USA; School of Graduate Studies, Rutgers University, Newark, NJ 07103, USA; Department of Pharmacology, Physiology, and Neuroscience, Rutgers-New Jersey Medical School, Newark, NJ 07103, USA
| | - Bruce A Citron
- Laboratory of Molecular Biology, Research & Development, Department of Veterans Affairs, VA New Jersey Health Care System, East Orange, NJ 07018, USA; School of Graduate Studies, Rutgers University, Newark, NJ 07103, USA; Department of Pharmacology, Physiology, and Neuroscience, Rutgers-New Jersey Medical School, Newark, NJ 07103, USA.
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Kozlova EV, Carabelli B, Bishay AE, Liu R, Denys ME, Macbeth JC, Piamthai V, Crawford MS, McCole DF, Zur Nieden NI, Hsiao A, Curras-Collazo MC. Induction of distinct neuroinflammatory markers and gut dysbiosis by differential pyridostigmine bromide dosing in a chronic mouse model of GWI showing persistent exercise fatigue and cognitive impairment. Life Sci 2022; 288:120153. [PMID: 34801513 PMCID: PMC9048156 DOI: 10.1016/j.lfs.2021.120153] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 11/10/2021] [Indexed: 12/03/2022]
Abstract
AIMS To characterize neuroinflammatory and gut dysbiosis signatures that accompany exaggerated exercise fatigue and cognitive/mood deficits in a mouse model of Gulf War Illness (GWI). METHODS Adult male C57Bl/6N mice were exposed for 28 d (5 d/wk) to pyridostigmine bromide (P.O.) at 6.5 mg/kg/d, b.i.d. (GW1) or 8.7 mg/kg/d, q.d. (GW2); topical permethrin (1.3 mg/kg), topical N,N-diethyl-meta-toluamide (33%) and restraint stress (5 min). Animals were phenotypically evaluated as described in an accompanying article [124] and sacrificed at 6.6 months post-treatment (PT) to allow measurement of brain neuroinflammation/neuropathic pain gene expression, hippocampal glial fibrillary acidic protein, brain Interleukin-6, gut dysbiosis and serum endotoxin. KEY FINDINGS Compared to GW1, GW2 showed a more intense neuroinflammatory transcriptional signature relative to sham stress controls. Interleukin-6 was elevated in GW2 and astrogliosis in hippocampal CA1 was seen in both GW groups. Beta-diversity PCoA using weighted Unifrac revealed that gut microbial communities changed after exposure to GW2 at PT188. Both GW1 and GW2 displayed systemic endotoxemia, suggesting a gut-brain mechanism underlies the neuropathological signatures. Using germ-free mice, probiotic supplementation with Lactobacillus reuteri produced less gut permeability than microbiota transplantation using GW2 feces. SIGNIFICANCE Our findings demonstrate that GW agents dose-dependently induce differential neuropathology and gut dysbiosis associated with cognitive, exercise fatigue and mood GWI phenotypes. Establishment of a comprehensive animal model that recapitulates multiple GWI symptom domains and neuroinflammation has significant implications for uncovering pathophysiology, improving diagnosis and treatment for GWI.
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Affiliation(s)
- Elena V Kozlova
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA, USA; Neuroscience Graduate Program, University of California, Riverside, CA, USA
| | - Bruno Carabelli
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA, USA
| | - Anthony E Bishay
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA, USA
| | - Rui Liu
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA, USA; Graduate Program in Genetics, Genomics, and Bioinformatics, University of California, Riverside, CA, USA
| | - Maximillian E Denys
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA, USA
| | - John C Macbeth
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA, USA; Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, USA
| | - Varadh Piamthai
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA, USA
| | - Meli'sa S Crawford
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, USA
| | - Declan F McCole
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, USA
| | - Nicole I Zur Nieden
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA, USA
| | - Ansel Hsiao
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA, USA
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Murray KE, Delic V, Ratliff WA, Beck KD, Citron BA. Acute gene expression changes in the mouse hippocampus following a combined Gulf War toxicant exposure. Life Sci 2021; 284:119845. [PMID: 34293396 PMCID: PMC8994630 DOI: 10.1016/j.lfs.2021.119845] [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: 01/15/2021] [Revised: 07/07/2021] [Accepted: 07/11/2021] [Indexed: 01/27/2023]
Abstract
AIMS Approximately 30% of the nearly 700,000 Veterans who were deployed to the Gulf War from 1990 to 1991 have reported experiencing a variety of symptoms including difficulties with learning and memory, depression and anxiety, and increased incidence of neurodegenerative diseases. Combined toxicant exposure to acetylcholinesterase (AChE) inhibitors has been studied extensively as a likely risk factor. In this study, we modeled Gulf War exposure in male C57Bl/6J mice with simultaneous administration of three chemicals implicated as exposure hazards for Gulf War Veterans: pyridostigmine bromide, the anti-sarin prophylactic; chlorpyrifos, an organophosphate insecticide; and the repellant N,N-diethyl-m-toluamide (DEET). MAIN METHODS Following two weeks of daily exposure, we examined changes in gene expression by whole transcriptome sequencing (RNA-Seq) with hippocampal isolates. Hippocampal-associated spatial memory was assessed with a Y-maze task. We hypothesized that genes important for neuronal health become dysregulated by toxicant-induced damage and that these detrimental inflammatory gene expression profiles could lead to chronic neurodegeneration. KEY FINDINGS We found dysregulation of genes indicating a pro-inflammatory response and downregulation of genes associated with neuronal health and several important immediate early genes (IEGs), including Arc and Egr1, which were both reduced approximately 1.5-fold. Mice exposed to PB + CPF + DEET displayed a 1.6-fold reduction in preference for the novel arm, indicating impaired spatial memory. SIGNIFICANCE Differentially expressed genes observed at an acute timepoint may provide insight into the pathophysiology of Gulf War Illness and further explanations for chronic neurodegeneration after toxicant exposure.
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Affiliation(s)
- Kathleen E Murray
- Laboratory of Molecular Biology, VA New Jersey Health Care System, Research & Development (Mailstop 15), Bldg. 16, Rm. 16-176, 385 Tremont Ave, East Orange, NJ 07018, United States of America; Rutgers School of Graduate Studies, Newark, NJ 07103, United States of America.
| | - Vedad Delic
- Laboratory of Molecular Biology, VA New Jersey Health Care System, Research & Development (Mailstop 15), Bldg. 16, Rm. 16-176, 385 Tremont Ave, East Orange, NJ 07018, United States of America; Rutgers School of Graduate Studies, Newark, NJ 07103, United States of America; Pharmacology, Physiology, and Neuroscience, Rutgers-New Jersey Medical School, Newark, NJ 07103, United States of America.
| | - Whitney A Ratliff
- Laboratory of Molecular Biology, Bay Pines VA Healthcare System, Research and Development, 151, Bldg. 22, Rm. 123, 10000 Bay Pines Blvd, Bay Pines, FL 33744, United States of America.
| | - Kevin D Beck
- Neurobehavior Research Laboratory, VA New Jersey Health Care System, Research & Development (Mailstop 15), Bldg. 16, Rm. 16-176, 385 Tremont Ave, East Orange, NJ 07018, United States of America; Rutgers School of Graduate Studies, Newark, NJ 07103, United States of America; Pharmacology, Physiology, and Neuroscience, Rutgers-New Jersey Medical School, Newark, NJ 07103, United States of America.
| | - Bruce A Citron
- Laboratory of Molecular Biology, VA New Jersey Health Care System, Research & Development (Mailstop 15), Bldg. 16, Rm. 16-176, 385 Tremont Ave, East Orange, NJ 07018, United States of America; Rutgers School of Graduate Studies, Newark, NJ 07103, United States of America; Laboratory of Molecular Biology, Bay Pines VA Healthcare System, Research and Development, 151, Bldg. 22, Rm. 123, 10000 Bay Pines Blvd, Bay Pines, FL 33744, United States of America; Pharmacology, Physiology, and Neuroscience, Rutgers-New Jersey Medical School, Newark, NJ 07103, United States of America.
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Masood MI, Hauke NT, Nasim MJ, Sarfraz M, Naseem M, Schäfer KH. Neural stem cell-based in vitro bioassay for the assessment of neurotoxic potential of water samples. J Environ Sci (China) 2021; 101:72-86. [PMID: 33334539 DOI: 10.1016/j.jes.2020.07.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 07/26/2020] [Accepted: 07/31/2020] [Indexed: 06/12/2023]
Abstract
Intensive agriculture activities, industrialization and growing numbers of wastewater treatment plants along river banks collectively contribute to the elevated levels of neurotoxic pollutants in natural water reservoirs across Europe. We established an in vitro bioassay based upon neural stem cells isolated from the subventricular zone of the postnatal mouse to evaluate the neurotoxic potential of raw wastewater, treated sewage effluent, groundwater and drinking water. The toxic potential of water samples was evaluated employing viability, proliferation, differentiation and migration assays. We found that raw wastewater could reduce the viability and proliferation of neural stem cells, and decreased the neuronal and astrocyte differentiation, neuronal neurite growth, astrocyte growth and cell migration. Treated sewage water also showed inhibitory effects on cell proliferation and migration. Our results indicated that relatively high concentrations of nitrogenous substances, pesticides, mercuric compounds, bisphenol-A, and phthalates, along with some other pollutants in raw wastewater and treated sewage water, might be the reason for the neuroinhibitory effects of these water samples. Our model successfully predicted the neurotoxicity of water samples collected from different sources and also revealed that the incomplete removal of contaminants from wastewater can be problematic for the developing nervous system. The presented data also provides strong evidence that more effective treatments should be used to minimize the contamination of water before release into major water bodies which may be considered as water reservoirs for human usage in the future.
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Affiliation(s)
- Muhammad Irfan Masood
- Division of Bioorganic Chemistry, School of Pharmacy, Saarland University, D-66123 Saarbrücken, Germany; ENS Group, University of Applied Sciences Kaiserslautern, 66482 Zweibrücken, Germany; Institute of Pharmaceutical Sciences, University of Veterinary and Animal Sciences, 54000 Lahore, Pakistan.
| | - Natalie Tamara Hauke
- Applied Life Sciences, University of Applied Sciences Kaiserslautern, 66482 Zweibrücken, Germany; Abwasserverband Bergstrasse, Altau 10, 69469 Weinheim, Germany
| | - Muhammad Jawad Nasim
- Division of Bioorganic Chemistry, School of Pharmacy, Saarland University, D-66123 Saarbrücken, Germany
| | - Muhammad Sarfraz
- Division of Bioorganic Chemistry, School of Pharmacy, Saarland University, D-66123 Saarbrücken, Germany
| | - Mahrukh Naseem
- Department of Zoology, University of Balochistan, Quetta 87550, Pakistan
| | - Karl Herbert Schäfer
- ENS Group, University of Applied Sciences Kaiserslautern, 66482 Zweibrücken, Germany.
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Sex-Based Differences in Plasma Autoantibodies to Central Nervous System Proteins in Gulf War Veterans versus Healthy and Symptomatic Controls. Brain Sci 2021; 11:brainsci11020148. [PMID: 33498629 PMCID: PMC7911379 DOI: 10.3390/brainsci11020148] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 01/08/2021] [Accepted: 01/20/2021] [Indexed: 02/07/2023] Open
Abstract
Veterans from the 1991 Gulf War (GW) have suffered from Gulf War illness (GWI) for nearly 30 years. This illness encompasses multiple body systems, including the central nervous system (CNS). Diagnosis and treatment of GWI is difficult because there has not been an objective diagnostic biomarker. Recently, we reported on a newly developed blood biomarker that discriminates GWI from GW healthy controls, and symptomatic controls with irritable bowel syndrome (IBS) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). The present study was designed to compare levels of these biomarkers between men and women with GWI, as well as sex-specific effects in comparison to healthy GW veterans and symptomatic controls (IBS, ME/CFS). The results showed that men and women with GWI differ in 2 of 10 plasma autoantibodies, with men showing significantly elevated levels. Men and women with GWI showed significantly different levels of autoantibodies in 8 of 10 biomarkers to neuronal and glial proteins in plasma relative to controls. In summary, the present study addressed the utility of the use of plasma autoantibodies for CNS proteins to distinguish among both men and women veterans with GWI and other healthy and symptomatic control groups.
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Hoffman JF, Kalinich JF. Effects of Incubation of Human Brain Microvascular Endothelial Cells and Astrocytes with Pyridostigmine Bromide, DEET, or Permethrin in the Absence or Presence of Metal Salts. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17228336. [PMID: 33187257 PMCID: PMC7696739 DOI: 10.3390/ijerph17228336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/05/2020] [Accepted: 11/09/2020] [Indexed: 12/19/2022]
Abstract
Gulf War Illness (GWI) is a chronic, multi-symptom illness suffered by over one-third of American military veterans who served in the Persian Gulf War between 1990 and 1991. No current single-exposure scenario accounts for all the symptoms observed in GWI, and instead may be due to a multi-exposure scenario. As a larger effort to understand how one category of multi-exposure scenarios of organic compounds such as nerve gas prophylactic pyridostigmine bromide, or insecticides/pesticides such as N,N-diethyl-m-toluamide (DEET) and permethrin, plus heavy metals found in inhaled dust particles (Al, Fe, Ni, Sr, DU, Co, Cu, Mn, and Zn) might play a role in neural aspects of GWI, we begin this initial study to examine the toxicity and oxidative damage markers of human brain endothelial cell and human astrocyte cell cultures in response to these compounds. A battery of cytotoxicity assessments, including the MTT assay, Neutral Red uptake, and direct microscopic observation, was used to determine a non-toxic dose of the test compounds. After testing a wide range of doses of each compound, we chose a sub-toxic dose of 10 µM for the three organic compounds and 1 µM for the nine metals of interest for co-exposure experiments on cell cultures and examined an array of oxidative stress-response markers including nitric oxide production, formation of protein carbonyls, production of thiobarbituric acid-reactive substances, and expression of proteins involved in oxidative stress and cell damage. Many markers were not significantly altered, but we report a significant increase in nitric oxide after exposure to any of the three compounds in conjunction with depleted uranium.
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Environmental Chemicals Altered in Association With Deployment for High Risk Areas. J Occup Environ Med 2020; 61 Suppl 12:S15-S24. [PMID: 31800447 DOI: 10.1097/jom.0000000000001647] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE A study was conducted using serum samples and high-resolution metabolomics (HRM) to test for changes in abundance of environmental chemicals in deployment in high-risk areas (Balad, Iraq; Bagram, Afghanistan). METHODS Pre and Post-deployment serum samples for deployment (cases) and matched controls stationed domestically were analyzed by HRM and bioinformatics for the relative abundance of 271 environmental chemicals. RESULTS Of the 271 chemicals, 153 were measurable in at least 80% of the samples in one of the pre- or post-deployment groups. Several pesticides and other chemicals were modestly elevated post-deployment in the Control as well as the Bagram and Balad samples. Similarly, small decreases were seen for some chemicals. CONCLUSION These results using serum samples show that for the 271 environmental chemicals studied, 56% were detected and small differences occurred with deployment to high-risk areas.
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Abou-Donia MB, Lapadula ES, Krengel MH, Quinn E, LeClair J, Massaro J, Conboy LA, Kokkotou E, Abreu M, Klimas NG, Nguyen DD, Sullivan K. Using Plasma Autoantibodies of Central Nervous System Proteins to Distinguish Veterans with Gulf War Illness from Healthy and Symptomatic Controls. Brain Sci 2020; 10:brainsci10090610. [PMID: 32899468 PMCID: PMC7563126 DOI: 10.3390/brainsci10090610] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 08/31/2020] [Accepted: 09/01/2020] [Indexed: 01/02/2023] Open
Abstract
For the past 30 years, there has been a lack of objective tools for diagnosing Gulf War Illness (GWI), which is largely characterized by central nervous system (CNS) symptoms emerging from 1991 Gulf War (GW) veterans. In a recent preliminary study, we reported the presence of autoantibodies against CNS proteins in the blood of veterans with GWI, suggesting a potential objective biomarker for the disorder. Now, we report the results of a larger, confirmatory study of these objective biomarkers in 171 veterans with GWI compared to 60 healthy GW veteran controls and 85 symptomatic civilian controls (n = 50 myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and n = 35 irritable bowel syndrome (IBS)). Specifically, we compared plasma markers of CNS autoantibodies for diagnostic characteristics of the four groups (GWI, GW controls, ME/CFS, IBS). For veterans with GWI, the results showed statistically increased levels of nine of the ten autoantibodies against neuronal "tubulin, neurofilament protein (NFP), Microtubule Associated Protein-2 (MAP-2), Microtubule Associated Protein-Tau (Tau), alpha synuclein (α-syn), calcium calmodulin kinase II (CaMKII)" and glial proteins "Glial Fibrillary Acidic Protein (GFAP), Myelin Associated Glycoprotein (MAG), Myelin Basic Protein (MBP), S100B" compared to healthy GW controls as well as civilians with ME/CFS and IBS. Next, we summed all of the means of the CNS autoantibodies for each group into a new index score called the Neurodegeneration Index (NDI). The NDI was calculated for each tested group and showed veterans with GWI had statistically significantly higher NDI values than all three control groups. The present study confirmed the utility of the use of plasma autoantibodies for CNS proteins to distinguish among veterans with GWI and other healthy and symptomatic control groups.
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Affiliation(s)
- Mohamed B. Abou-Donia
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA;
- Correspondence: (M.B.A.-D.); (K.S.); Tel.: +1-919-684-2221 (M.B.A.-D.)
| | - Elizabeth S. Lapadula
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA;
| | - Maxine H. Krengel
- Department of Neurology, Boston University School of Medicine, Boston, MA 02118, USA;
| | - Emily Quinn
- Departments of Biostatistics and Environmental Health, Boston University School of Public Health, Boston, MA 02118, USA; (E.Q.); (J.L.); (J.M.); (D.D.N.)
| | - Jessica LeClair
- Departments of Biostatistics and Environmental Health, Boston University School of Public Health, Boston, MA 02118, USA; (E.Q.); (J.L.); (J.M.); (D.D.N.)
| | - Joseph Massaro
- Departments of Biostatistics and Environmental Health, Boston University School of Public Health, Boston, MA 02118, USA; (E.Q.); (J.L.); (J.M.); (D.D.N.)
| | - Lisa A. Conboy
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA; (L.A.C.); (E.K.)
| | - Efi Kokkotou
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA; (L.A.C.); (E.K.)
| | - Maria Abreu
- Dr. Kiran C. Patel College of Osteopathic Medicine, Institute for Neuroimmune Medicine, Nova Southeastern University, Fort Lauderdale, FL 33314, USA; (M.A.); (N.G.K.)
- Department of Immunology, Miami VA Medical Center, Miami, FL 33125, USA
| | - Nancy G. Klimas
- Dr. Kiran C. Patel College of Osteopathic Medicine, Institute for Neuroimmune Medicine, Nova Southeastern University, Fort Lauderdale, FL 33314, USA; (M.A.); (N.G.K.)
- Department of Immunology, Miami VA Medical Center, Miami, FL 33125, USA
| | - Daniel D. Nguyen
- Departments of Biostatistics and Environmental Health, Boston University School of Public Health, Boston, MA 02118, USA; (E.Q.); (J.L.); (J.M.); (D.D.N.)
| | - Kimberly Sullivan
- Departments of Biostatistics and Environmental Health, Boston University School of Public Health, Boston, MA 02118, USA; (E.Q.); (J.L.); (J.M.); (D.D.N.)
- Correspondence: (M.B.A.-D.); (K.S.); Tel.: +1-919-684-2221 (M.B.A.-D.)
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The Low Glutamate Diet Effectively Improves Pain and Other Symptoms of Gulf War Illness. Nutrients 2020; 12:nu12092593. [PMID: 32859032 PMCID: PMC7551234 DOI: 10.3390/nu12092593] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/17/2020] [Accepted: 08/20/2020] [Indexed: 01/19/2023] Open
Abstract
Gulf War Illness (GWI) is a multisymptom disorder including widespread chronic pain, fatigue and gastrointestinal problems. The objective of this study was to examine the low glutamate diet as a treatment for GWI. Forty veterans with GWI were recruited from across the US. Outcomes included symptom score, myalgic score, tender point count, dolorimetry and the Chalder Fatigue Scale. Subjects were randomized to the low glutamate diet or a wait-listed control group, with symptom score being compared after one month. Subjects then went onto a double-blind, placebo-controlled crossover challenge with monosodium glutamate (MSG)/placebo to test for return of symptoms. Symptom score was compared between diet intervention and wait-listed controls with an independent t-test and effect size was calculated with Cohen’s d. Change scores were analyzed with Wilcoxon Signed Rank tests. Crossover challenge results were analyzed with General Linear Models and cluster analysis. The diet intervention group reported significantly less symptoms (p = 0.0009) than wait-listed controls, with a very large effect size, d = 1.16. Significant improvements in average dolorimetry (p = 0.0006), symptom score, tender point number, myalgic score and the Chalder Fatigue Scale (all p < 0.0001) were observed after the 1-month diet. Challenge with MSG/placebo resulted in significant variability in individual response. These results suggest that the low glutamate diet can effectively reduce overall symptoms, pain and fatigue in GWI, but differential results upon challenge suggest that other aspects of the diet, or underlying differences within the population, may be driving these changes. Future research is needed to identify potential nutrient effects, biomarkers, and underlying metabolic differences between responders and non-responders.
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Haleem ZM, Yadav S, Cushion ML, Tanner RJ, Carek PJ, Mainous AG. Exposure to N,N-Diethyl-Meta-Toluamide Insect Repellent and Human Health Markers: Population Based Estimates from the National Health and Nutrition Examination Survey. Am J Trop Med Hyg 2020; 103:812-814. [PMID: 32458781 DOI: 10.4269/ajtmh.20-0226] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
N,N-diethyl-meta-toluamide (DEET) is one of the most commonly used insect repellants in the United States, yet the existing literature regarding DEET's potential deleterious impact on humans is mixed and is based mostly on case reports. The primary aim of this study was to address this lack of population-based evidence of the effects of DEET exposure on human health in the United States. Our primary outcome measures were biomarkers related to systemic inflammation (high sensitivity C-reactive protein), immune function (lymphocyte), liver function (aspartate aminotransferase, alanine aminotransferase, and γ-glutamyl transferace), and kidney function (estimated glomerular filtration rate). We analyzed data from the population-based National Health and Nutrition Examination Survey, 2015-2016, and identified 1,205 patients (age 20+ years) who had DEET metabolite levels recorded at or above detection limits. A Pearson correlation was used to assess the relationship between DEET metabolite, and each biomarker found there was no significant correlation. Thus, there is no evidence that DEET exposure has any impact on the biomarkers identified.
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Affiliation(s)
- Zuhair M Haleem
- Department of Health Services Research, Management, and Policy, University of Florida, Gainesville, Florida
| | - Sandhya Yadav
- Department of Health Services Research, Management, and Policy, University of Florida, Gainesville, Florida
| | - Minor L Cushion
- Department of Health Services Research, Management, and Policy, University of Florida, Gainesville, Florida
| | - Rebecca J Tanner
- Department of Health Services Research, Management, and Policy, University of Florida, Gainesville, Florida
| | - Peter J Carek
- Department of Community Health and Family Medicine, University of Florida, Gainesville, Florida
| | - Arch G Mainous
- Department of Health Services Research, Management, and Policy, University of Florida, Gainesville, Florida.,Department of Community Health and Family Medicine, University of Florida, Gainesville, Florida
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Behavioral, cellular and molecular maladaptations covary with exposure to pyridostigmine bromide in a rat model of gulf war illness pain. Toxicol Appl Pharmacol 2018; 352:119-131. [PMID: 29803855 DOI: 10.1016/j.taap.2018.05.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 05/16/2018] [Accepted: 05/20/2018] [Indexed: 12/12/2022]
Abstract
Many veterans of Operation Desert Storm (ODS) struggle with the chronic pain of Gulf War Illness (GWI). Exposure to insecticides and pyridostigmine bromide (PB) have been implicated in the etiology of this multisymptom disease. We examined the influence of 3 (DEET (N,N-diethyl-meta-toluamide), permethrin, chlorpyrifos) or 4 GW agents (DEET, permethrin, chlorpyrifos, pyridostigmine bromide (PB)) on the post-exposure ambulatory and resting behaviors of rats. In three independent studies, rats that were exposed to all 4 agents consistently developed both immediate and delayed ambulatory deficits that persisted at least 16 weeks after exposures had ceased. Rats exposed to a 3 agent protocol (PB excluded) did not develop any ambulatory deficits. Cellular and molecular studies on nociceptors harvested from 16WP (weeks post-exposure) rats indicated that vascular nociceptor Nav1.9 mediated currents were chronically potentiated following the 4 agent protocol but not following the 3 agent protocol. Muscarinic linkages to muscle nociceptor TRPA1 were also potentiated in the 4 agent but not the 3 agent, PB excluded, protocol. Although Kv7 activity changes diverged from the behavioral data, a Kv7 opener, retigabine, transiently reversed ambulation deficits. We concluded that PB played a critical role in the development of pain-like signs in a GWI rat model and that shifts in Nav1.9 and TRPA1 activity were critical to the expression of these pain behaviors.
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Qiang L, Rao AN, Mostoslavsky G, James MF, Comfort N, Sullivan K, Baas PW. Reprogramming cells from Gulf War veterans into neurons to study Gulf War illness. Neurology 2017; 88:1968-1975. [PMID: 28507260 DOI: 10.1212/wnl.0000000000003938] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 02/23/2017] [Indexed: 12/28/2022] Open
Abstract
Gulf War illness (GWI), which afflicts at least 25% of veterans who served in the 1990-1991 war in the Persian Gulf, is thought to be caused by deployment exposures to various neurotoxicants, including pesticides, anti-nerve gas pills, and low-level nerve agents including sarin/cyclosarin. GWI is a multisymptom disorder characterized by fatigue, joint pain, cognitive problems, and gastrointestinal complaints. The most prominent symptoms of GWI (memory problems, poor attention/concentration, chronic headaches, mood alterations, and impaired sleep) suggest that the disease primarily affects the CNS. Development of urgently needed treatments depends on experimental models appropriate for testing mechanistic hypotheses and for screening therapeutic compounds. Rodent models have been useful thus far, but are limited by their inability to assess the contribution of genetic or epigenetic background to the disease, and because disease-vulnerable proteins and pathways may be different in humans relative to rodents. As of yet, no postmortem tissue from the veterans has become available for research. We are moving forward with a paradigm shift in the study of GWI, which utilizes contemporary stem cell technology to convert somatic cells from Gulf War veterans into pluripotent cell lines that can be differentiated into various cell types, including neurons, glia, muscle, or other relevant cell types. Such cell lines are immortal and will be a resource for GWI researchers to pursue mechanistic hypotheses and therapeutics.
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Affiliation(s)
- Liang Qiang
- From the Department of Neurobiology and Anatomy (L.Q., A.N.R., P.W.B.), Drexel University, Philadelphia, PA; and Center for Regenerative Medicine (G.M., M.F.J.) and School of Public Health (N.C., K.S.), Boston University, Boston, MA
| | - Anand N Rao
- From the Department of Neurobiology and Anatomy (L.Q., A.N.R., P.W.B.), Drexel University, Philadelphia, PA; and Center for Regenerative Medicine (G.M., M.F.J.) and School of Public Health (N.C., K.S.), Boston University, Boston, MA
| | - Gustavo Mostoslavsky
- From the Department of Neurobiology and Anatomy (L.Q., A.N.R., P.W.B.), Drexel University, Philadelphia, PA; and Center for Regenerative Medicine (G.M., M.F.J.) and School of Public Health (N.C., K.S.), Boston University, Boston, MA
| | - Marianne F James
- From the Department of Neurobiology and Anatomy (L.Q., A.N.R., P.W.B.), Drexel University, Philadelphia, PA; and Center for Regenerative Medicine (G.M., M.F.J.) and School of Public Health (N.C., K.S.), Boston University, Boston, MA
| | - Nicole Comfort
- From the Department of Neurobiology and Anatomy (L.Q., A.N.R., P.W.B.), Drexel University, Philadelphia, PA; and Center for Regenerative Medicine (G.M., M.F.J.) and School of Public Health (N.C., K.S.), Boston University, Boston, MA
| | - Kimberly Sullivan
- From the Department of Neurobiology and Anatomy (L.Q., A.N.R., P.W.B.), Drexel University, Philadelphia, PA; and Center for Regenerative Medicine (G.M., M.F.J.) and School of Public Health (N.C., K.S.), Boston University, Boston, MA
| | - Peter W Baas
- From the Department of Neurobiology and Anatomy (L.Q., A.N.R., P.W.B.), Drexel University, Philadelphia, PA; and Center for Regenerative Medicine (G.M., M.F.J.) and School of Public Health (N.C., K.S.), Boston University, Boston, MA.
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Screening for novel central nervous system biomarkers in veterans with Gulf War Illness. Neurotoxicol Teratol 2017; 61:36-46. [DOI: 10.1016/j.ntt.2017.03.002] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 03/02/2017] [Accepted: 03/03/2017] [Indexed: 12/19/2022]
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Flunker LK, Nutter TJ, Johnson RD, Cooper BY. DEET potentiates the development and persistence of anticholinesterase dependent chronic pain signs in a rat model of Gulf War Illness pain. Toxicol Appl Pharmacol 2016; 316:48-62. [PMID: 28025109 DOI: 10.1016/j.taap.2016.12.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 12/16/2016] [Accepted: 12/20/2016] [Indexed: 12/18/2022]
Abstract
Exposure to DEET (N,N-diethyl-meta-toluamide) may have influenced the pattern of symptoms observed in soldiers with GWI (Gulf War Illness; Haley and Kurt, 1997). We examined how the addition of DEET (400mg/kg; 50% topical) to an exposure protocol of permethrin (2.6mg/kg; topical), chlorpyrifos (CP; 120mg/kg), and pyridostigmine bromide (PB;13mg/kg) altered the emergence and pattern of pain signs in an animal model of GWI pain (Nutter et al., 2015). Rats underwent behavioral testing before, during and after a 4week exposure: 1) hindlimb pressure withdrawal threshold; 2) ambulation (movement distance and rate); and 3) resting duration. Additional studies were conducted to assess the influence of acute DEET (10-100μM) on muscle and vascular nociceptor Kv7, KDR, Nav1.8 and Nav1.9. We report that a 50% concentration of DEET enhanced the development and persistence of pain-signs. Rats exposed to all 4 compounds exhibited ambulation deficits that appeared 5-12weeks post-exposure and persisted through weeks 21-24. Rats exposed to only three agents (CP or PB excluded), did not fully develop ambulation deficits. When PB was excluded, rats also developed rest duration pain signs, in addition to ambulation deficits. There was no evidence that physiological doses of DEET acutely modified nociceptor Kv7, KDR, Nav1.8 or Nav1.9 activities. Nevertheless, DEET augmented protocols decreased the conductance of Kv7 expressed in vascular nociceptors harvested from chronically exposed rats. We concluded that DEET enhanced the development and persistence of pain behaviors, but the anticholinesterases CP and PB played a determinant role.
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Affiliation(s)
- L K Flunker
- Division of Neuroscience, Dept. of Oral and Maxillofacial Surgery, Box 100416, JHMHC, University of Florida College of Dentistry, Gainesville, FL 32610, USA.
| | - T J Nutter
- Division of Neuroscience, Dept. of Oral and Maxillofacial Surgery, Box 100416, JHMHC, University of Florida College of Dentistry, Gainesville, FL 32610, USA.
| | - R D Johnson
- Dept. of Physiological Sciences, University of Florida College of Veterinary Science, Gainesville, FL 32610, USA.
| | - B Y Cooper
- Division of Neuroscience, Dept. of Oral and Maxillofacial Surgery, Box 100416, JHMHC, University of Florida College of Dentistry, Gainesville, FL 32610, USA.
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Roland PS, Haley RW, Yellin W, Owens K, Shoup AG, Holt GR. Vestibular Dysfunction in Gulf War Syndrome. Otolaryngol Head Neck Surg 2016. [DOI: 10.1016/s0194-5998(00)70041-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
METHODS: Vestibular complaints of Gulf War veterans were characterized by a nested case-control study of 23 veterans with 3 different Gulf War syndromes and 20 matched control subjects. All subjects completed a standardized symptom questionnaire and underwent standard audiovestibular tests administered by audiologists blinded to group identities. RESULTS: The prevalence of reported dizzy spells was higher in veterans with Gulf War syndromes 1 (100%), 2 (85%), and 3 (100%) than in controls (25%, P < 0.0001). Dizzy spells were more frequent, lasted longer, and involved a wider variety of accompanying symptoms in veterans with syndrome 2 than in those with syndromes 1 and 3. Audiovestibular testing showed greater interocular asymmetry of nystagmic velocity on sinusoidal harmonic acceleration in syndromes 1 ( P = 0.015) and 2 ( P = 0.002), greater asymmetry of saccadic velocity in syndrome 2 ( P = 0.4), diminished nystagmic velocity after caloric stimulation bilaterally in syndrome 3 (P = 0.02 to 0.04), more subjects with pathologic nystagmus ( P = 0.09), and greater interside asymmetry of wave I to III interpeak latency on auditory brain stem response in syndromes 1 ( P = 0.005) and 2 ( P = 0.07). Asymmetry of gain on sinusoidal harmonic acceleration and pathologic nystagmus were most strongly associated with symptoms of paroxysmal vertigo (P = 0.002 and 0.07, respectively); asymmetry of saccadic velocity, with the severity of vertigo (P = 0.004); and abnormal caloric response, with chronic dysequilibrium ( P = 0.006). CONCLUSIONS: The findings are compatible with a subtle neurologic injury from organophosphate-induced delayed neurotoxicity.
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Affiliation(s)
| | - Robert W. Haley
- Epidemiology Division, Department of Internal Medicine, University of Texas Southwestern Medical Center
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Cooper BY, Johnson RD, Nutter TJ. Exposure to Gulf War Illness chemicals induces functional muscarinic receptor maladaptations in muscle nociceptors. Neurotoxicology 2016; 54:99-110. [PMID: 27058124 DOI: 10.1016/j.neuro.2016.04.001] [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: 01/20/2016] [Revised: 03/31/2016] [Accepted: 04/01/2016] [Indexed: 12/12/2022]
Abstract
Chronic pain is a component of the multisymptom disease known as Gulf War Illness (GWI). There is evidence that pain symptoms could have been a consequence of prolonged and/or excessive exposure to anticholinesterases and other GW chemicals. We previously reported that rats exposed, for 8 weeks, to a mixture of anticholinesterases (pyridostigmine bromide, chlorpyrifos) and a Nav (voltage activated Na(+) channel) deactivation-inhibiting pyrethroid, permethrin, exhibited a behavior pattern that was consistent with a delayed myalgia. This myalgia-like behavior was accompanied by persistent changes to Kv (voltage activated K(+)) channel physiology in muscle nociceptors (Kv7, KDR). In the present study, we examined how exposure to the above agents altered the reactivity of Kv channels to a muscarinic receptor (mAChR) agonist (oxotremorine-M). Comparisons between muscle nociceptors harvested from vehicle and GW chemical-exposed rats revealed that mAChR suppression of Kv7 activity was enhanced in exposed rats. Yet in these same muscle nociceptors, a Stromatoxin-insensitive component of the KDR (voltage activated delayed rectifier K(+) channel) exhibited decreased sensitivity to activation of mAChR. We have previously shown that a unique mAChR-induced depolarization and burst discharge (MDBD) was exaggerated in muscle nociceptors of rats exposed to GW chemicals. We now provide evidence that both muscle and vascular nociceptors of naïve rats exhibit MDBD. Examination of the molecular basis of the MDBD in naïve animals revealed that while the mAChR depolarization was independent of Kv7, the action potential burst was modulated by Kv7 status. mAChR depolarizations were shown to be dependent, in part, on TRPA1. We argue that dysfunction of the MDBD could be a functional convergence point for maladapted ion channels and receptors consequent to exposure to GW chemicals.
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Affiliation(s)
- B Y Cooper
- Division of Neuroscience, Dept. of Oral and Maxillofacial Surgery, Box 100416, JHMHC, University of Florida College of Dentistry, Gainesville, FL 32610, USA.
| | - R D Johnson
- Dept. of Physiological Sciences, University of Florida College of Veterinary Science, Gainesville, FL 32610, USA.
| | - T J Nutter
- Division of Neuroscience, Dept. of Oral and Maxillofacial Surgery, Box 100416, JHMHC, University of Florida College of Dentistry, Gainesville, FL 32610, USA.
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Phillips KF, Deshpande LS. Repeated low-dose organophosphate DFP exposure leads to the development of depression and cognitive impairment in a rat model of Gulf War Illness. Neurotoxicology 2015; 52:127-33. [PMID: 26619911 DOI: 10.1016/j.neuro.2015.11.014] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 11/20/2015] [Accepted: 11/22/2015] [Indexed: 02/02/2023]
Abstract
Approximately 175,000-250,000 of the returning veterans from the 1991 Persian Gulf War exhibit chronic multi-symptom illnesses that includes neurologic co-morbidities such as depression, anxiety and cognitive impairments. Amongst a host of causative factors, exposure to low levels of the nerve agent Sarin has been strongly implicated for expression of Gulf War Illness (GWI). Nerve agents similar to pesticides are organophosphate (OP) compounds. There is evidence from civilian population that exposure to OPs such as in agricultural workers and nerve agents such as the survivors and first-responders of the Tokyo subway Sarin gas attack suffer from chronic neurological problems similar to GWI symptoms. Given this unique chemical profile, OPs are ideal to study the effects of nerve agents and develop models of GWI in civilian laboratories. In this study, we used repeated low-dose exposure to OP agent diisopropyl fluorophosphate (DFP) over a 5-day period to approximate the duration and level of Sarin exposure during the Persian Gulf War. We tested the rats at 3-months post DFP exposure. Using a battery of behavioral assays, we observed the presence of symptoms of chronic depression, anxiety and memory problems as characterized by increased immobility time in the Forced Swim Test, anhedonia in the Sucrose Preference Test, anxiety in the Elevated Plus Maze, and spatial memory impairments in the Object Location Test, respectively. Chronic low dose DFP exposure was also associated with hippocampal neuronal damage as characterized by the presence of Fluoro-Jade staining. Given that OP exposure is considered a leading cause of GWI related morbidities, this animal model will be ideally suited to study underlying molecular mechanisms for the expression of GWI neurological symptoms and identify drugs for the effective treatment of GWIs.
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Affiliation(s)
- Kristin F Phillips
- Department of Neurology, Virginia Commonwealth University, Richmond, VA 23298, USA
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Wang HP, Liang YJ, Sun YJ, Hou WY, Chen JX, Long DX, Xu MY, Wu YJ. Subchronic neurotoxicity of chlorpyrifos, carbaryl, and their combination in rats. ENVIRONMENTAL TOXICOLOGY 2014; 29:1193-1200. [PMID: 23418109 DOI: 10.1002/tox.21851] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 01/04/2013] [Accepted: 01/06/2013] [Indexed: 06/01/2023]
Abstract
Anticholinesterase pesticides have been widely used in agricultural and domestic settings and can be detected in the environment after long-term use. Although the acute toxic effects of chlorpyrifos and carbaryl have been well described, little is known about the chronic toxicity of the pesticides mixture. To investigate their chronic neurotoxicity, Wistar rats were exposed to chlorpyrifos, carbaryl, and their mixture (MIX) for 90 consecutive days. The activities of serum cholinesterase (ChE) as well as acetylcholinesterase (AChE) and neuropathy target esterase (NTE) in nerve tissues were determined. Furthermore, the histopathological examination was carried out. The results showed that ChE activity significantly decreased in all treated rats except the rats treated with low dose carbaryl. Treatment with middle- and high-dose chlorpyrifos and MIX in rats significantly inhibited AChE activity in the central nervous tissues, whereas treatment with carbaryl alone did not. In sciatic nerve, AChE activity was significantly inhibited by high-dose carbaryl and MIX, but not by chlorpyrifos alone. No significant NTE inhibition was observed in all treatment groups. Histopathological examination revealed that both chlorpyrifos and MIX treatment induced hippocampal damage. However, no obvious hippocampal damage was found in carbaryl-treated rats. Carbaryl and MIX, but not chlorpyrifos alone, induced pathological damage of sciatic nerve. Taken together, all of the results indicated that chlorpyrifos and carbaryl have different toxicological target tissues in nervous system and showed corresponding effects in the nervous tissues, which may reflect the different sensitivity of central and peripheral nervous tissues to different pesticides individually and in combination.
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Affiliation(s)
- Hui-Ping Wang
- Laboratory of Molecular Toxicology, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1-5 Beichenxi Road, Beijing 100101, People's Republic of China
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Persistent modification of Nav1.9 following chronic exposure to insecticides and pyridostigmine bromide. Toxicol Appl Pharmacol 2014; 277:298-309. [DOI: 10.1016/j.taap.2014.04.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 03/14/2014] [Accepted: 04/03/2014] [Indexed: 12/21/2022]
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Effects of subchronic exposure to N,N-diethyl-m-toluamide on selected biomarkers in common carp (Cyprinus carpio L.). BIOMED RESEARCH INTERNATIONAL 2014; 2014:828515. [PMID: 24795897 PMCID: PMC3985181 DOI: 10.1155/2014/828515] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 02/27/2014] [Accepted: 02/28/2014] [Indexed: 01/24/2023]
Abstract
DEET (N,N-diethyl-m-toluamide) is the most common active ingredient in the insect repellents commonly detected in European groundwater. The aim of this study was to investigate the effect of subchronic DEET exposure on biochemical and haematological parameters, antioxidant enzymes, including catalase, glutathione peroxidase, glutathione reductase, and glutathione S-transferase, and the amount of thiobarbituric acid reactive substances (TBARS) in common carp (Cyprinus carpio L.). Two specific proinflammatory and anti-inflammatory cytokine genes were selected to assess an immunological status of the fish. Fish were exposed for 28 days to three concentrations of DEET (1.0 µg/L, 0.1 mg/L, and 1.0 mg/L) where 1 µg/L is corresponding to the concentration found in the environment. DEET had a significant (P < 0.05) effect on increased RBC, decreased mean corpuscular volume (MCV), and mean corpuscular haemoglobin value (MCH) compared to control groups in the concentration of 1 mg/L. A significant decline (P < 0.05) in triacylglycerols (TAG) in plasma was found in the concentration of 1 mg/L compared to the control groups. The parameters of oxidative stress in tissues of common carp were weekly affected and immunological parameters were not affected.
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Koslik HJ, Hamilton G, Golomb BA. Mitochondrial dysfunction in Gulf War illness revealed by 31Phosphorus Magnetic Resonance Spectroscopy: a case-control study. PLoS One 2014; 9:e92887. [PMID: 24675771 PMCID: PMC3968048 DOI: 10.1371/journal.pone.0092887] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 02/27/2014] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Approximately 1/3 of 1990-1 Gulf War veterans developed chronic multisymptom health problems. Implicated exposures bear mechanisms that adversely affect mitochondria. Symptoms emphasize fatigue, cognition and muscle (brain and muscle are aerobically demanding); with protean additional domains affected, compatible with mitochondrial impairment. Recent evidence supports treatments targeting cell bioenergetics (coenzyme10) to benefit Gulf War illness symptoms. However, no evidence has directly documented mitochondrial or bioenergetic impairment in Gulf War illness. OBJECTIVE We sought to objectively assess for mitochondrial dysfunction, examining post-exercise phosphocreatine-recovery time constant (PCr-R) using (31)Phosphorus Magnetic Resonance Spectroscopy ((31)P-MRS), in Gulf War veterans with Gulf War illness compared to matched healthy controls. PCr-R has been described as a "robust and practical" index of mitochondrial status. DESIGN AND PARTICIPANTS Case-control study from 2012-2013. Fourteen community-dwelling Gulf War veterans and matched controls from the San Diego area comprised 7 men meeting CDC and Kansas criteria for Gulf War illness, and 7 non-deployed healthy controls matched 1:1 to cases on age, sex, and ethnicity. OUTCOME MEASURE Calf muscle phosphocreatine was evaluated by (31)P-MRS at rest, through 5 minutes of foot pedal depression exercise, and in recovery, to assess PCr-R. Paired t-tests compared cases to matched controls. RESULTS PCr-R was significantly prolonged in Gulf War illness cases vs their matched controls: control values, mean ± SD, 29.0 ± 8.7 seconds; case values 46.1 ± 18.0 seconds; difference 17.1 ± 14.9 seconds; p = 0.023. PCr-R was longer for cases relative to their matched controls for all but one pair; moreover while values clustered under 31 seconds for all but one control, they exceeded 35 seconds (with a spread up to 70 seconds) for all but one case. DISCUSSION These data provide the first direct evidence supporting mitochondrial dysfunction in Gulf War illness. Findings merit replication in a larger study and/or corroboration with additional mitochondrial assessment tools.
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Affiliation(s)
- Hayley J. Koslik
- Department of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Gavin Hamilton
- Department of Radiology, University of California San Diego, La Jolla, California, United States of America
| | - Beatrice A. Golomb
- Department of Medicine, University of California San Diego, La Jolla, California, United States of America
- Department of Family and Preventive Medicine, University of California San Diego, La Jolla, California, United States of America
- * E-mail:
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Cauli O, Piedrafita B, Llansola M, Felipo V. Gender differential effects of developmental exposure to methyl-mercury, polychlorinated biphenyls 126 or 153, or its combinations on motor activity and coordination. Toxicology 2013; 311:61-8. [DOI: 10.1016/j.tox.2012.11.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 11/15/2012] [Accepted: 11/27/2012] [Indexed: 11/17/2022]
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Kuklenyik P, Baker SE, Bishop AM, Morales-A P, Calafat AM. On-line solid phase extraction-high performance liquid chromatography-isotope dilution-tandem mass spectrometry approach to quantify N,N-diethyl-m-toluamide and oxidative metabolites in urine. Anal Chim Acta 2013; 787:267-73. [PMID: 23830449 DOI: 10.1016/j.aca.2013.05.055] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2013] [Revised: 05/20/2013] [Accepted: 05/31/2013] [Indexed: 01/26/2023]
Abstract
Human exposure to N,N-diethyl-m-toluamide (DEET) occurs because of the widespread use of DEET as an active ingredient in insect repellents. However, information on the extent of such exposure is rather limited. Therefore, we developed a fast on-line solid phase extraction-high performance liquid chromatography-isotope dilution tandem mass spectrometry (HPLC-MS/MS) method to measure in urine the concentrations of DEET and two of its oxidative metabolites: N,N-diethyl-3-(hydroxymethyl)benzamide and 3-(diethylcarbamoyl)benzoic acid (DCBA). To the best of our knowledge, this is the first HPLC-MS/MS method for the simultaneous quantification of DEET and its select metabolites in human urine. After enzymatic hydrolysis of the conjugated species in 0.1 mL of urine, the target analytes were retained and pre-concentrated on a monolithic column, separated from each other and from other urinary biomolecules on a reversed-phase analytical column, and detected by atmospheric pressure chemical ionization in positive ion mode. The limits of detection ranged from 0.1 ng mL(-1) to 1.0 ng mL(-1), depending on the analyte. Accuracy ranged between 90.4 and 104.9%, and precision ranged between 5.5 and 13.1% RSD, depending on the analyte and the concentration. We tested the usefulness of this method by analyzing 75 urine samples collected anonymously in the Southeastern United States in June 2012 from adults with no known exposure to DEET. Thirty eight samples (51%) tested positive for at least one of the analytes. We detected DCBA most frequently and at the highest concentrations. Our results suggest that this method can be used for the analysis of a large number of samples for epidemiological studies to assess human exposure to DEET.
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Affiliation(s)
- Peter Kuklenyik
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA
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Manikkam M, Tracey R, Guerrero-Bosagna C, Skinner MK. Pesticide and insect repellent mixture (permethrin and DEET) induces epigenetic transgenerational inheritance of disease and sperm epimutations. Reprod Toxicol 2012; 34:708-19. [PMID: 22975477 DOI: 10.1016/j.reprotox.2012.08.010] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Revised: 08/02/2012] [Accepted: 08/03/2012] [Indexed: 11/16/2022]
Abstract
Environmental compounds are known to promote epigenetic transgenerational inheritance of disease. The current study was designed to determine if a "pesticide mixture" (pesticide permethrin and insect repellent N,N-diethyl-meta-toluamide, DEET) promotes epigenetic transgenerational inheritance of disease and associated DNA methylation epimutations in sperm. Gestating F0 generation female rats were exposed during fetal gonadal sex determination and the incidence of disease evaluated in F1 and F3 generations. There were significant increases in the incidence of total diseases in animals from pesticide lineage F1 and F3 generation animals. Pubertal abnormalities, testis disease, and ovarian disease (primordial follicle loss and polycystic ovarian disease) were increased in F3 generation animals. Analysis of the pesticide lineage F3 generation sperm epigenome identified 363 differential DNA methylation regions (DMR) termed epimutations. Observations demonstrate that a pesticide mixture (permethrin and DEET) can promote epigenetic transgenerational inheritance of adult onset disease and potential sperm epigenetic biomarkers for ancestral environmental exposures.
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Affiliation(s)
- Mohan Manikkam
- Center for Reproductive Biology, School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, United States
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In vitro kinetic interactions of DEET, pyridostigmine and organophosphorus pesticides with human cholinesterases – Response to the letter to the editor. Chem Biol Interact 2011. [DOI: 10.1016/j.cbi.2011.03.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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In vitro kinetic interactions of DEET, pyridostigmine and organophosphorus pesticides with human cholinesterases. Chem Biol Interact 2011; 190:79-83. [PMID: 21354413 DOI: 10.1016/j.cbi.2011.02.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Revised: 02/17/2011] [Accepted: 02/18/2011] [Indexed: 11/20/2022]
Abstract
The simultaneous use of the repellent DEET, pyridostigmine, and organophosphorus pesticides has been assumed as a potential cause for the Gulf War Illness and combinations have been tested in different animal models. However, human in vitro data on interactions of DEET with other compounds are scarce and provoked the present in vitro study scrutinizing the interactions of DEET, pyridostigmine and pesticides with human acetylcholinesterase (hAChE) and butyrylcholinesterase (hBChE). DEET showed to be a weak and reversible inhibitor of hAChE and hBChE. The IC(50) of DEET was calculated to be 21.7mM DEET for hAChE and 3.2mM DEET for hBChE. The determination of the inhibition kinetics of pyridostigmine, malaoxon and chlorpyrifos oxon with hAChE in the presence of 5mM DEET resulted in a moderate reduction of the inhibition rate constant k(i). The decarbamoylation velocity of pyridostigmine-inhibited hAChE was not affected by DEET. In conclusion, the in vitro investigation of interactions between human cholinesterases, DEET, pyridostigmine, malaoxon and chlorpyrifos oxon showed a weak inhibition of hAChE and hBChE by DEET. The inhibitory potency of the tested cholinesterase inhibitors was not enhanced by DEET and it did not affect the regeneration velocity of pyridostigmine-inhibited AChE. Hence, this in vitro study does not give any evidence of a synergistic effect of the tested compounds on human cholinesterases.
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Seng KY, Loke WK, Moochhala S, Zhao B, Lee JDE. Retrospective population pharmacokinetic/pharmacodynamic analysis of pyridostigmine, a cholinesterase inhibitor, in Chinese males. J Pharm Pharmacol 2010. [DOI: 10.1211/jpp.61.09.0008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
Objectives
We have characterised the population pharmacokinetics-pharmacodynamics of pyridostigmine given as pyridostigmine bromide.
Methods
Over three days 50 healthy Chinese male subjects each received seven doses of 30 mg pyridostigmine bromide orally (3 times 10 mg every 8 h). Plasma concentrations of pyridostigmine and red blood cell acetylcholinesterase (AChE) activity were determined at various times within the eight hours after the first and the seventh doses. The resulting pharmacokinetic data were fitted to a single compartment open model with first-order absorption and elimination. The pharmacodynamics were modelled using an inhibitory Emax model. The potential influence of demographic and biological covariates on the model parameters was investigated. Nonlinear mixed effects modelling was performed using NONMEM.
Key findings
The apparent clearance and volume of distribution as well as absorption rate constant of plasma pyridostigmine were estimated to be 136 1/h, 130 1 and 0.68 1/h, respectively. The maximum red blood cell AChE activity decrease (Emax) and plasma pyridostigmine concentration producing 50% of this reduction (EC50) were estimated to be 9.32 AChE units per gram haemoglobin and 51.9 ng/ml, respectively. None of the tested covariates were found to be correlated with any of the model parameters. Dosing simulations suggested that 30 mg repeated every six hours might be needed to achieve steady-state trough percentage inhibition above the recommended 10% in healthy Chinese males.
Conclusions
The pharmacokinetics and the effects of pyridostigmine on red blood cell AChE activity were described using a mixed effects model. For Chinese males, the dosing interval may have been shorter than that recommended for the Caucasian population. Additional studies are needed to confirm these findings.
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Affiliation(s)
- Kok-Yong Seng
- Bioengineering Laboratory, Defence Medical & Environmental Research Institute, DSO National Laboratories, 27 Medical Drive, Singapore
| | - Weng-Keong Loke
- Agent Diagnostic and Therapeutics Laboratory, Defence Medical & Environmental Research Institute, DSO National Laboratories, 20 Science Park, Singapore
| | - Shabbir Moochhala
- Combat Casualty Care Programme, Defence Medical & Environmental Research Institute, DSO National Laboratories, 27 Medical Drive, Singapore
| | - Bin Zhao
- Combat Casualty Care Programme, Defence Medical & Environmental Research Institute, DSO National Laboratories, 27 Medical Drive, Singapore
| | - Jon-Deoon Edmund Lee
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 10 Medical Drive, Singapore
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Risher JF, Todd GD, Meyer D, Zunker CL. The elderly as a sensitive population in environmental exposures: making the case. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2010; 207:95-157. [PMID: 20652665 DOI: 10.1007/978-1-4419-6406-9_2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The US population is aging. CDC has estimated that 20% of all Americans will be 65 or older by the year 2030. As a part of the aging process, the body gradually deteriorates and physiologic and metabolic limitations arise. Changes that occur in organ anatomy and function present challenges for dealing with environmental stressors of all kinds, ranging from temperature regulation to drug metabolism and excretion. The elderly are not just older adults, but rather are individuals with unique challenges and different medical needs than younger adults. The ability of the body to respond to physiological challenge presented by environmental chemicals is dependent upon the health of the organ systems that eliminate those substances from the body. Any compromise in the function of those organ systems may result in a decrease in the body's ability to protect itself from the adverse effects of xenobiotics. To investigate this issue, we performed an organ system-by-organ system review of the effects of human aging and the implications for such aging on susceptibility to drugs and xenobiotics. Birnbaum (1991) reported almost 20 years ago that it was clear that the pharmacokinetic behavior of environmental chemicals is, in many cases, altered during aging. Yet, to date, there is a paucity of data regarding recorded effects of environmental chemicals on elderly individuals. As a result, we have to rely on what is known about the effects of aging and the existing data regarding the metabolism, excretion, and adverse effects of prescription medications in that population to determine whether the elderly might be at greater risk when exposed to environmental substances. With increasing life expectancy, more and more people will confront the problems associated with advancing years. Moreover, although proper diet and exercise may lessen the immediate severity of some aspects of aging, the process will continue to gradually degrade the ability to cope with a variety of injuries and diseases. Thus, the adverse effects of long-term, low-level exposure to environmental substances will have a longer time to be manifested in a physiologically weakened elderly population. When such exposures are coupled with concurrent exposure to prescription medications, the effects could be devastating. Public health officials must be knowledgeable about the sensitivity of the growing elderly population, and ensure that the use of health guidance values (HGVs) for environmental contaminants and other substances give consideration to this physiologically compromised segment of the population.
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Affiliation(s)
- John F Risher
- Agency for Toxic Substances and Disease Registry, Division of Toxicology (F-32), Toxicology Information Branch, 1600 Clifton Road, Atlanta, GA 30333, USA.
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Corbel V, Stankiewicz M, Pennetier C, Fournier D, Stojan J, Girard E, Dimitrov M, Molgó J, Hougard JM, Lapied B. Evidence for inhibition of cholinesterases in insect and mammalian nervous systems by the insect repellent deet. BMC Biol 2009; 7:47. [PMID: 19656357 PMCID: PMC2739159 DOI: 10.1186/1741-7007-7-47] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2009] [Accepted: 08/05/2009] [Indexed: 11/29/2022] Open
Abstract
Background N,N-Diethyl-3-methylbenzamide (deet) remains the gold standard for insect repellents. About 200 million people use it every year and over 8 billion doses have been applied over the past 50 years. Despite the widespread and increased interest in the use of deet in public health programmes, controversies remain concerning both the identification of its target sites at the olfactory system and its mechanism of toxicity in insects, mammals and humans. Here, we investigated the molecular target site for deet and the consequences of its interactions with carbamate insecticides on the cholinergic system. Results By using toxicological, biochemical and electrophysiological techniques, we show that deet is not simply a behaviour-modifying chemical but that it also inhibits cholinesterase activity, in both insect and mammalian neuronal preparations. Deet is commonly used in combination with insecticides and we show that deet has the capacity to strengthen the toxicity of carbamates, a class of insecticides known to block acetylcholinesterase. Conclusion These findings question the safety of deet, particularly in combination with other chemicals, and they highlight the importance of a multidisciplinary approach to the development of safer insect repellents for use in public health.
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Affiliation(s)
- Vincent Corbel
- Laboratoire de Lutte contre les Insectes Nuisibles, Institut de Recherche pour Développement, F-34 394 Montpellier, France.
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Gultekin F, Karakoyun I, Sutcu R, Savik E, Cesur G, Orhan H, Delibas N. CHLORPYRIFOS INCREASES THE LEVELS OF HIPPOCAMPAL NMDA RECEPTOR SUBUNITS NR2A AND NR2B IN JUVENILE AND ADULT RATS. Int J Neurosci 2009; 117:47-62. [PMID: 17365099 DOI: 10.1080/00207450500535719] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The present study investigated the effect of chlorpyrifos on NMDA receptor subunits NR2A and NR2B in juvenile and adult rats. Chlorpyrifos was administered with the dose of 40 and 70 mg/kg to juvenile and adult rats, respectively. Chlorpyrifos significantly inhibited the AChE activity in juvenile and adult rats (p < .05). NR2A and NR2B levels significantly increased in juvenile and adult rats by chlorpyrifos application (p < .05). Increased NR2A and NR2B levels may reflect increased glutaminergic activity, consequently neuronal damage. In the case of neuronal damage, learning and memory could be affected negatively even though NR2A and NR2B increased.
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Affiliation(s)
- Fatih Gultekin
- Suleyman Demirel University, School of Medicine, Department of Biochemistry, Isparta, Turkey.
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Antibodies to squalene in US Navy Persian Gulf War veterans with chronic multisymptom illness. Vaccine 2009; 27:3921-6. [DOI: 10.1016/j.vaccine.2009.03.091] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Revised: 03/24/2009] [Accepted: 03/29/2009] [Indexed: 11/23/2022]
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Keil DE, McGuinn WD, Dudley AC, EuDaly JG, Gilkeson GS, Peden-Adams MM. N,N,-diethyl-m-toluamide (DEET) suppresses humoral immunological function in B6C3F1 mice. Toxicol Sci 2009; 108:110-23. [PMID: 19141786 DOI: 10.1093/toxsci/kfp001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
N,N-diethyl-meta-toluamide (DEET) is a particularly effective broad-spectrum insect repellent used commonly in recreational, occupational and military environments. Due to its widespread use and suggested link to Gulf War Illness, this study examined the immunotoxicity of DEET. Adult female B6C3F1 mice were injected sc for 14 days with DEET at 0, 7.7, 15.5, 31, or 62 mg/kg/day. Due to differences in the dermal absorption of DEET between mice and humans, this study eliminated this confounding factor by utilizing sc injection and measured circulating blood levels of DEET to assess bioavailability from sc administration. Effects on lymphocyte proliferation, natural killer cell activity, thymus and spleen weight and cellularity, the antibody plaque-forming cell (PFC) response, and thymic and splenic CD4/CD8 lymphocyte subpopulations were assessed 24 h after the last dose. No effect was observed in lymphocyte proliferation, natural killer cell activity, thymic weight, splenic weight, thymic cellularity, or splenic cellularity. Significant decreases were observed in the percentage of splenic CD4-/CD8- and CD4+/CD8- lymphocytes but only at the 62 mg DEET/kg/day treatment level and not in absolute numbers of these cells types. Additionally, significant decreases in the antibody PFC response were observed following treatment with 15.5, 31, or 62 mg DEET/kg/day. Pharmacokinetic (PK) data from the current study indicate 95% bioavailability of the administered dose. Therefore, it is likely that DEET exposure ranges applied in this study are comparable to currently reported occupational usage. Together, the evidence for immunosuppression and available PK data suggest a potential human health risk associated with DEET in the occupational or military environments assuming similar sensitivity between human and rodent responses.
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Affiliation(s)
- Deborah E Keil
- Clinical Laboratory Sciences, University of Nevada-Las Vegas, Las Vegas, Nevada 89154, USA.
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Hodgson E, Rose RL. Human Metabolism and Metabolic Interactions of Deployment-Related Chemicals. Drug Metab Rev 2008; 37:1-39. [PMID: 15747499 DOI: 10.1081/dmr-200046955] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
It has been suggested that chemicals and, more specifically, chemical interactions, are involved as causative agents in deployment-related illnesses. Unfortunately, this hypothesis has proven difficult to test, because toxicological investigations of deployment-related chemicals are usually carried out on surrogate animals and are difficult to extrapolate to humans. Other parts of the problem, such as the definition of variation within human populations and the development of methods for designating groups or individuals at significantly greater risk, cannot be carried out on surrogate animals, and the data must be derived from humans. The relatively recent availability of human cell.fractions, such as microsomes, cytosol, etc., human cells such as primary hepatocytes, recombinant human enzymes, and their isoforms and polymorphic variants has enabled a significant start to be made in developing the human data needed. These initial studies have examined the human metabolism by cytochrome P450, other phase I enzymes, and their isoforms and, in some cases, their polymorphic variants of compounds such as chlorpyrifos, carbaryl, DEET, permethrin, and pyridostigmine bromide, and, to a lesser extent, other chemicals from the same chemical and use classes, including solvents, jet fuel components, and sulfur mustard metabolites. A number of interactions at the metabolic level have been described both with respect to other xenobiotics and to endogenous metabolites. Probably the most dramatic have been seen in the ability of chlorpyrifos to inhibit not only the metabolism of other xenobiotics such as carbaryl and DEET but also to inhibit the metabolism of steroid hormones.
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Affiliation(s)
- Ernest Hodgson
- Department of Environmental and Molecular Toxicology, Box 7633, North Carolina State University, Raleigh, NC 27695, USA.
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Abu-Qare AW, Abou-Donia MB. In vitro metabolism and interactions of pyridostigmine bromide, N,N-diethyl-m-toluamide, and permethrin in human plasma and liver microsomal enzymes. Xenobiotica 2008; 38:294-313. [PMID: 18274958 DOI: 10.1080/00498250701813230] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
1. The in vitro human plasma activity and liver microsomal metabolism of pyridostigmine bromide (PB), a prophylactic treatment against organophosphate nerve agent attack, N,N-diethyl-m-toluamide (DEET), an insect repellent, and permethrin, a pyrethroid insecticide, either alone or in combination were investigated. 2. The three chemicals disappeared from plasma in the following order: permethrin > PB > DEET. The combined incubation of DEET with either permethrin or PB had no effect on permethrin or PB. Binary incubation with permethrin decreased the metabolism of PB and its disappearance from plasma and binary incubation with PB decreased the metabolism of permethrin and its clearance from plasma. Incubation with PB and/or permethrin shortened the DEET terminal half-life in plasma. These agents behaved similarly when studied in liver microsomal assays. The combined incubation of DEET with PB or permethrin (alone or in combination) diminished DEET metabolism in microsomal systems. 3. The present study evidences that PB and permethrin are metabolized by both human plasma and liver microsomal enzymes and that DEET is mainly metabolized by liver oxidase enzymes. Combined exposure to test chemicals increases their neurotoxicity by impeding the body's ability to eliminate them because of the competition for detoxifying enzymes.
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Affiliation(s)
- A W Abu-Qare
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
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Acute Toxicity and Cholinesterase Inhibition in Chicks Dosed Orally with Organophosphate Insecticides. Arh Hig Rada Toksikol 2008; 59:145-51. [DOI: 10.2478/10004-1254-59-2008-1873] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acute Toxicity and Cholinesterase Inhibition in Chicks Dosed Orally with Organophosphate InsecticidesAcute toxic effects of three commonly used insecticidal preparations of the organophosphates chlorpyrifos, diazinon, and dichlorvos were examined in mixed breed broiler chicks, and cholinesterase activity in plasma and brain were measured. The acute (24 h) oral median lethal doses (LD50) of chlorpyrifos, diazinon, and dichlorvos were 10.79 mg kg-1, 6.32 mg kg-1, and 6.30 mg kg-1, respectively, as determined by the up-and-down method in chicks. Signs of cholinergic toxicosis in the chicks appeared within two hours after dosing, and they included salivation, lacrimation, gasping, frequent defecation, drooping of wings, tremors, convulsions, and recumbency before death. Halving the oral LD50 of chlorpyrifos (5 mg kg-1), diazinon (3 mg kg-1), and dichlorvos (3 mg kg-1) caused immobility and wing drooping, but not the clinical signs of cholinergic toxicity. However, at full LD50 doses of these insecticides, chicks showed clinical signs of cholinergic toxicity similar to those seen in the LD50 experiments. Two out of six chicks died within two hours after treatment with LD50 doses of chlorpyrifos and dichlorvos, whereas LD50 dosing with diazinon caused death in three out of six chicks. Compared to control values, the insecticides reduced plasma and whole brain cholinesterase activities by 29 % to 84 % and 18 % to 77 %, respectively, depending on the dose. The decrease in plasma cholinesterase correlated well (r = 0.82) with that of the brain. These data suggest that organophosphate insecticides administered orally at LD50 doses induce clinical signs of cholinergic poisoning and concurrently reduce brain and plasma cholinesterase activities in chicks.
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Repeated stress in combination with pyridostigmine Part I: long-term behavioural consequences. Behav Brain Res 2008; 197:301-10. [PMID: 18793677 DOI: 10.1016/j.bbr.2008.08.031] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Revised: 08/21/2008] [Accepted: 08/24/2008] [Indexed: 11/21/2022]
Abstract
Since their return from the first Persian Gulf War, some veterans have complained of a variety of symptoms that were designated as "Gulf War Illness" (GWI). Among other factors, pyridostigmine, used as a prophylaxis treatment against intoxication by nerve agents, has been proposed by many authors as a cause of late social and/or cognitive dysfunction related to GWI. One of the hypotheses placed to explain these behavioural disorders is that operational stress has modified the side effects of pyridostigmine given to soldiers. In an attempt to establish an experimental model of GWI to evaluate the long-term behavioural effects of pyridostigmine administered in stressful conditions, we have developed a new model of repeated stress based on the pole-climbing avoidance technique. We used it to evaluate the effects of pyridostigmine treatment combined to repeated stress over the months following the end of the treatment. We observed that this stress induces impulsiveness and aggressiveness in adult male rat. Moreover, pyridostigmine treatment administered daily 30 min before each stressful session amplifies these behavioural disorders and induces long-term learning dysfunction and slight but significant decrease in phosphocholine level in hippocampus. This suggests that repeated administration of pyridostigmine combined to pole-climbing avoidance (PCA) stress conditions can induce adverse effects in rat central nervous system.
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Park D, Jeon JH, Shin S, Jang JY, Choi BI, Nahm SS, Kang JK, Hwang SY, Kim JC, Kim YB. Debilitating stresses do not increase blood-brain barrier permeability: Lack of the involvement of corticosteroids. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2008; 26:30-37. [PMID: 21783884 DOI: 10.1016/j.etap.2008.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2007] [Revised: 12/24/2007] [Accepted: 01/03/2008] [Indexed: 05/31/2023]
Abstract
The involvement of corticosteroids in stress-induced change in blood-brain barrier (BBB) permeability was investigated. Mice were adrenalectomized and administered with pyridostigmine bromide (PB) or Evan's blue, markers of BBB penetration, followed by 18-h cold-restraint stress (CRS). Rats were administered with mifepristone, a corticosteroid receptor blocker, and the markers, followed by 4-h water immersion-restraint stress (WIRS). Separately, soman was administered to induce seizures-mediated BBB opening. CRS did not induce PB and Evan's blue penetration, which were not affected by adrenalectomy. Also, the markers were not detected in the brain of rats subjected to WIRS, regardless of the treatment of mifepristone. In comparison, 1-h epileptic seizures increased the penetration of Evan's blue by 875%. The results suggest that in contrast to seizure-related BBB opening, profound stresses do not practically increase the BBB permeability, and that corticosteroids are not involved in the stress-induced BBB penetration of charged chemicals and albumin-dye complex.
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Affiliation(s)
- Dongsun Park
- College of Veterinary Medicine and Research Institute of Veterinary Medicine, Chungbuk National University, 410 Seongbongro (Gaeshin-dong), Cheongju, Chungbuk 361-763, Republic of Korea
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Developmental exposure to polychlorinated biphenyls or methylmercury, but not to its combination, impairs the glutamate-nitric oxide-cyclic GMP pathway and learning in 3-month-old rats. Neuroscience 2008; 154:1408-16. [PMID: 18556134 DOI: 10.1016/j.neuroscience.2008.05.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Revised: 05/12/2008] [Accepted: 05/13/2008] [Indexed: 11/21/2022]
Abstract
Prenatal exposure to polychlorinated biphenyls (PCBs) or methylmercury (MeHg) contaminated food may affect brain development, leading to long-term alterations in cognitive function. Both types of contaminants, PCBs and MeHg, are often found together contaminating food, especially fish in some polluted areas. Exposure to combinations of neurotoxicants may exert different effects on the developing nervous system than exposure to individual contaminants. Developmental exposure (during pregnancy and lactation) to PCB126 or PCB153 impairs learning ability when the rats are 3 months old. Impairment of learning seems to be a consequence of impairment of the function of the glutamate-nitric oxide (NO)-cGMP pathway in brain in vivo. The aims of the present work were 1) to assess whether perinatal exposure to MeHg also affects the function of the glutamate-NO-cGMP pathway in brain in vivo analyzed by in vivo brain microdialysis and/or the ability to learn the Y maze task when the rats are 3 months old, and 2) to assess whether perinatal exposure to combinations of MeHg with PCB153 or PCB126 potentiates, decreases or does not modify the effects of the individual neurotoxicants. Perinatal exposure to PCB126, PCB153 or MeHg impaired the function of the glutamate-NO-cGMP pathway in cerebellum and learning ability. However, co-exposure to PCB126+MeHg or PCB153+MeHg inhibits the impairment of the pathway or learning ability. These results support that the function of this pathway modulates learning of the Y maze task. Moreover, they show that co-exposure to these PCBs and MeHg does not exacerbate, but reduces the effects on the ability to learn this task.
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Khoobdel M, Jonaidi N. Laboratory determination of protection time in four chemical repellents against Anopheles stephensi. Pak J Biol Sci 2007; 10:2714-2718. [PMID: 19070088 DOI: 10.3923/pjbs.2007.2714.2718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In the present study we determined the Protection Time (PT) and Failure Time (FT) of the DMP lotion, which is synthesized and formulated in Iran and it was compared with other products such as MIP60 and Dimp31.7 lotions (commercial and current formulations of dimethyl phthalate) and trench pomade (a popular local repellent in Iran) against Anopheles stephensi Liston (main malaria vector in south of Iran) in laboratory condition. In this research which is an interventional and experimental study, the screen cage method was used to estimate PT and FT of repellents against An. stephensi. The following commercial formulations of chemical repellents were tested: Iranian DMP lotion (DMP60) (contains 60% dimethyl phthalate, 25% isopropyl alcohol, 5% twine 80 and 10% water), MIP60 and Dimp31.7 lotions contains 60 and 31.7% active ingredient of dimethyl phthalate and trench pomade (a combination of N,N-diethyl-m-toluamide (DEET) and DMP). Test was done on human volunteers. In this test some defined amount of repellents applied on human volunteer's forearm and then was inserted in cage against mosquitoes biting to determine PT and FT. According to the results of this research, the PT of Iranian DMP60 lotion against An. stephensi was determined about 274 min (SE = ++/-.04), which didn't have any significant difference with MIP60 and trench pomade, but it was significantly more than Dimp31.7. Furthermore the FT of DMP60 against An. stephensi was determined about 327 min (SE = +/-10.47), that in this case it had a significant deference with MIP60 lotion and trench pomade. The failure time of DMP60 was less than another two repellents. The Iranian DMP60 lotion can potentially compete with MIP60 and Dimp31.7, but to increase the FT rate, its formulation need to be improved.
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Affiliation(s)
- Mehdi Khoobdel
- Military Health Research Center, Military Medicine Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
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Roy MJ, Kraus PL, Seegers CA, Young SYN, Kamens DR, Law WA, Cherstniakova SA, Chang DN, Cooper JA, Sato PA, Matulich W, Krantz DS, Cantilena LR, Deuster PA. Pyridostigmine, diethyltoluamide, permethrin, and stress: a double-blind, randomized, placebo-controlled trial to assess safety. Mayo Clin Proc 2006; 81:1303-10. [PMID: 17036555 DOI: 10.4065/81.10.1303] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVE To determine whether short-term human exposure to pyridostigmine bromide, diethyltoluamide, and permethrin, at rest or under stress, adversely affects short-term physical or neurocognitive performance. PARTICIPANTS AND METHODS A multicenter, prospective, double-blind, placebo-controlled crossover trial exposing 64 volunteers to permethrin-impregnated uniforms, diethyltoluamide-containing skin cream, oral pyridostigmine, and corresponding placebos was performed. Each participant had 4 separate sessions, ensuring exposure to all treatments and placebos under both stress and rest conditions in random order. Outcomes Included physical performance (handgrip strength and duration, stair climbing, and pull-ups [males] or push-ups [females]), neurocognitive performance (computerized tests), and self-reported adverse effects. RESULTS Permethrin was undetectable in the serum of all participants; pyridostigmine levels were higher Immediately after stress (41.6 ng/mL; 95% confidence Interval, 35.1-48.1 ng/mL) than rest (23.0 ng/mL; 95% confidence Interval, 19.2-26.9 ng/mL), whereas diethyltoluamide levels did not significantly differ by stress condition. Heart rate and systolic blood pressure increased significantly with stress compared with rest but did not vary with treatment vs placebo. Physical and neurocognitive outcome measures and self-reported adverse effects did not significantly differ by exposure group. CONCLUSION Combined, correct use of pyridostigmine, diethyltoluamide, and permethrin is well tolerated and without evidence of short-term physical or neurocognitive impairment.
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Affiliation(s)
- Michael J Roy
- Division of Military Internal Medicine, Department of Medicine, Room A3062, Uniformed Services University, 4301 Jones Bridge Rd, Bethesda, MD 20814, USA.
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Hunt SC, Jakupcak M, McFall M, Orsborn M, Felker B, Larson S, Klevens M. Re: "Chronic multisymptom illness complex in Gulf War I veterans 10 years later". Am J Epidemiol 2006; 164:708-9; author reply 709-10. [PMID: 16943267 DOI: 10.1093/aje/kwj297] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Abstract
Concerns about unexplained illnesses among veterans of the 1991 Gulf War appeared soon after that conflict ended. Many environmental causes have been suggested, including possible exposure to depleted uranium munitions, vaccines and other drugs used to protect troops, deliberate or accidental exposure to chemical warfare agents and pesticides and smoke from oil-well fires. To help resolve these issues, US and UK governments have sought independent expert scientific advice from prestigious, independent scientific and public health experts, including the US National Academies of Science and the UK Royal Society and Medical Research Council. Their authoritative and independent scientific and medical reviews shed light on a wide range of Gulf War environmental hazards. However, they have added little to our understanding of Gulf War veterans' illnesses, because identified health effects have been previously well characterized, primarily in the occupational health literature. This effort has not identified any new health effects or unique syndromes associated with the evaluated environmental hazards. Nor do their findings provide an explanation for significant amounts of illnesses among veterans of the 1991 Gulf War. Nevertheless, these independent and highly credible scientific reviews have proven to be an effective means for evaluating potential health effects from deployment-related environmental hazards.
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Affiliation(s)
- Mark Brown
- US Department of Veterans Affairs Office of Public Health and Environmental Hazards, Washington, DC 20420, USA.
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Pahwa P, McDuffie HH, Dosman JA, McLaughlin JR, Spinelli JJ, Robson D, Fincham S. Hodgkin lymphoma, multiple myeloma, soft tissue sarcomas, insect repellents, and phenoxyherbicides. J Occup Environ Med 2006; 48:264-74. [PMID: 16531830 DOI: 10.1097/01.jom.0000183539.20100.06] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE The objective of this study was to determine if there is an additional risk of developing Hodgkin lymphoma, multiple myeloma, or soft tissue sarcoma as a consequence of exposure to a combination of phenoxyherbicides, rubber gloves, DEET (N, N-diethyl-m-toluamide), and sunlight compared with each of the individual chemicals. METHODS This was a population-based study of men with specific cancers and age, province-matched control subjects. RESULTS No additional risk from these combinations of exposures of developing these three types of tumor was found in contrast to non-Hodgkin lymphoma. CONCLUSIONS The mechanisms by which phenoxyherbicides contribute to the risk of multiple myeloma and non-Hodgkin lymphoma may be different.
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Affiliation(s)
- Punam Pahwa
- Institute of Agricultural Rural and Environmental Health, University of Saskatchewan, Saskatchewan, Canada
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Usmani KA, Cho TM, Rose RL, Hodgson E. Inhibition of the Human Liver Microsomal and Human Cytochrome P450 1A2 and 3A4 Metabolism of Estradiol by Deployment-Related and Other Chemicals. Drug Metab Dispos 2006; 34:1606-14. [PMID: 16790556 DOI: 10.1124/dmd.106.010439] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cytochromes P450 (P450s) are major catalysts in the metabolism of xenobiotics and endogenous substrates such as estradiol (E2). It has previously been shown that E2 is predominantly metabolized in humans by CYP1A2 and CYP3A4 with 2-hydroxyestradiol (2-OHE2) the major metabolite. This study examines effects of deployment-related and other chemicals on E2 metabolism by human liver microsomes (HLM) and individual P450 isoforms. Kinetic studies using HLM, CYP3A4, and CYP1A2 showed similar affinities (Km) for E2 with respect to 2-OHE2 production. Vmax and CLint values for HLM are 0.32 nmol/min/mg protein and 7.5 microl/min/mg protein; those for CYP3A4 are 6.9 nmol/min/nmol P450 and 291 microl/min/nmol P450; and those for CYP1A2 are 17.4 nmol/min/nmol P450 and 633 microl/min/nmol P450. Phenotyped HLM use showed that individuals with high levels of CYP1A2 and CYP3A4 have the greatest potential to metabolize E2. Preincubation of HLM with a variety of chemicals, including those used in military deployments, resulted in varying levels of inhibition of E2 metabolism. The greatest inhibition was observed with organophosphorus compounds, including chlorpyrifos and fonofos, with up to 80% inhibition for 2-OHE2 production. Carbaryl, a carbamate pesticide, and naphthalene, a jet fuel component, inhibited ca. 40% of E2 metabolism. Preincubation of CYP1A2 with chlorpyrifos, fonofos, carbaryl, or naphthalene resulted in 96, 59, 84, and 87% inhibition of E2 metabolism, respectively. Preincubation of CYP3A4 with chlorpyrifos, fonofos, deltamethrin, or permethrin resulted in 94, 87, 58, and 37% inhibition of E2 metabolism. Chlorpyrifos inhibition of E2 metabolism is shown to be irreversible.
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El-Masry EM, Abou-Donia MB. Interaction of pyridostigmine bromide and N,N-diethyl-m-toluamide alone and in combination with P-glycoprotein expressed in Escherichia coli leaky mutant. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2006; 69:919-33. [PMID: 16728371 DOI: 10.1080/15287390500360588] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
P-glycoprotein (P-gp), the most extensively studied ATP-binding transporter, functions as a biological barrier by extruding toxic substances and xenobiotics out of the cell. This study was carried out to determine the effect of N,N-diethyl-m-toluamide (DEET) and pyridostigmine bromide (PB), alone and in combination, on P-gp expression using Escherichia coli leaky mutant transformed with Mdr1 gene (pT5-7/mdr1), which codes for P-gp or lactose permease (pT5-7/lacY) as negative control. Also, daunomycin (a known P-gp sustrate) was used as a positive control and reserpine (a known P-gp inhibitor) served as a negative control. An in vitro cell-resistant assay was used to monitor the potential of test compounds to interact with P-gp. Following exposure of the cells to pyridostigmine bromide or daunomycin, P-gp conferred significant resistance against both compounds, while reserpine and DEET significantly inhibited the glycoprotein. Cells were grown in the presence of noncytotoxic concentrations of daunomycin, pyridostigmine bromide, reserpine, or DEET, and membrane fractions were examined by Western immunoblotting for expression of P-gp. Daunomycin induced P-gp expression quantitatively more than pyridostigmine bromide, while reserpine and DEET significantly inhibited P-gp expression in cells harboring mdr1. Photoaffinity labeling experiment performed with the P-gp ligand [125I]iodoarylazidoprazosin demonstrated that compounds that induced or inhibited P-gp transport activity also bound to P-gp. DEET was also found to be a potent inhibitor of P-gp-mediated ATPase activity, whereas pyridostigmine bromide increased P-gp ATPase activity. Cells expressing P-gp or lac permease were exposed to pyridostigmine bromide and DEET, alone and in combination. Noncytotoxic concentrations of DEET significantly inhibited P-gp-mediated resistance against pyridostigmine bromide, resulting in a reduction of the number of effective drug interactions with biological targets. An explanation of these results might be that DEET is a third-generation inhibitor of P-gp; it has high potency and specificity for P-gp, it inhibits hydrolysis of ATP, it exerts no appreciable impact on cytochrome P-450 3A4, and it prevents transport of xenobiotics, such as pyridostigmine bromide, out of the cell. This conclusion explains, at least in part, the increased toxicity and bioavailability of pyridostigmine bromide following combined administration with DEET. This study improves our understanding of the basis of chemical interactions with DEET by defining the ability of drugs to interact with P-gp either as inhibitors or substrates, which may in turn lead to altered efficacy or toxicity.
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Affiliation(s)
- Eman M El-Masry
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
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McDuffie HH, Pahwa P, Robson D, Dosman JA, Fincham S, Spinelli JJ, McLaughlin JR. Insect Repellents, Phenoxyherbicide Exposure, and Non-Hodgkinʼs Lymphoma. J Occup Environ Med 2005; 47:806-16. [PMID: 16093930 DOI: 10.1097/01.jom.0000167260.80687.78] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE We sought to test a hypothetical explanation of contradictory results in studies of phenoxyherbicides and NHL, that the exposure of rubber gloves recommended for use by farmers when mixing or applying pesticides simultaneously to 2,4-D (2,4-dichlorophenoxyacetic acid), DEET (N,N-diethyl-m-toluamide), and ultraviolet rays increased their permeability to 2,4-D. METHODS We conducted a case (NHL n = 513)/control (n = 1506) study among men using age; province of residence; exposure to insect repellents containing DEET, phenoxy-herbicides, or dicamba; and gloves when handling pesticides. RESULTS Using conditional logistic regression, the stratum with reported exposure to mecoprop, to DEET and the use of rubber gloves had higher odds ratios (3.86; 95% confidence interval = 1.57-9.49) compared with strata with other combinations. CONCLUSIONS In conclusion, the etiologic complexity of NHL was demonstrated.
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Affiliation(s)
- Helen H McDuffie
- Institute of Agricultural Rural and Environmental Health, University of Saskatchewan, Saskatoon, SK, S7N 0W8, Canada.
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Kelsall H, Macdonell R, Sim M, Forbes A, McKenzie D, Glass D, Ikin J, Ittak P. Neurological status of Australian veterans of the 1991 Gulf War and the effect of medical and chemical exposures. Int J Epidemiol 2005; 34:810-9. [PMID: 15851393 DOI: 10.1093/ije/dyi084] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Since the 1991 Gulf War, concerns have been voiced about the effects on the health of veterans of Gulf War related medical and chemical exposures. METHODS Our cross-sectional study compared 1424 male Australian Gulf War veterans and a randomly sampled military comparison group (n = 1548). A postal questionnaire asked about the presence of current neurological type symptoms, medically diagnosed neurological conditions, and medical and chemical exposures. A neurological examination was performed as part of a physical assessment. RESULTS Veterans have a higher prevalence of neurological type symptoms (ratio of means 1.4, 95% confidence interval (CI) 1.2-1.5). Although the odds ratio (OR) of lower limb neurological type symptoms and signs in veterans compared with the comparison group was increased (OR = 1.6, 95% CI 1.0-2.7), it was of borderline significance, and there was no difference between groups according to a Neuropathy Score based on neurological signs alone (ratio of means 1.1, 95% CI 0.9-1.3). The increased OR of neurological type symptoms and signs suggestive of a central nervous system disorder (OR = 1.8, 95% CI 1.0-3.1) was also of borderline significance. Veterans were not more likely to have self-reported medically diagnosed neurological conditions, or to have neurological type symptoms and signs suggestive of an anterior horn cell disorder (OR = 0.9, 95% CI 0.5-1.6). The total number of neurological type symptoms reported by veterans, but not the Neuropathy Score, was associated with Gulf War related exposures including immunizations and pyridostigmine bromide in dose-response relationships, anti-biological warfare tablets, solvents, pesticides, and insect repellents. CONCLUSIONS This study shows increased reporting of neurological type symptoms in Gulf War veterans, but no evidence for increased neurological effects based on objective physical signs. There may be a number of factors, including information bias, relating to increased neurological type symptom reporting in veterans.
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Affiliation(s)
- Helen Kelsall
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria 3004, Australia.
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Abstract
Since the end of the 1991 Gulf War about 20,000 United States veterans and similar proportions of troops from other allied contingents have been affected by a variety of symptoms which have collectively become known as 'Gulf War Syndrome'. Similar symptoms have been reported in Iraqi civilians including children. Despite extensive investigations no agreement has been reached on whether there is an underlying cause or causes. In this article, the principal features of the illness are summarised and some of the proposed causes discussed. It is proposed that the common cause is the toxic smoke from incomplete combustion of oil from burning wells, and this hypothesis is related to the known toxicology of two likely combustion products, nitric oxide and carbon monoxide. The effect of this proposal on possible investigations and treatment is considered.
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Peden-Adams MM, Dudley AC, EuDaly JG, Allen CT, Gilkeson GS, Keil DE. Pyridostigmine Bromide (PYR) Alters Immune Function in B6C3F1 Mice. Immunopharmacol Immunotoxicol 2004; 26:1-15. [PMID: 15106728 DOI: 10.1081/iph-120029939] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Pyridostigmine bromide (PYR) is an anticholinesterase drug indicated for the treatment of myasthenia gravis and neuromuscular blockade reversal. It acts as a reversible cholinesterase inhibitor and was used as a pretreatment for soldiers during Operation Desert Storm to protect against possible nerve gas attacks. Since that time, PYR has been implicated as a possible causative agent contributing to Gulf War Illness. PYR's mechanism of action has been well-delineated with regards to its effects on the nervous system, yet little is known regarding potential effects on immunological function. To evaluate the effects of PYR on immunological function, adult female B6C3F1 mice were gavaged daily for 14 days with PYR (0, 1, 5, 10, or 20 mg/kg/day). Immune parameters assessed were lymphoproliferation, natural killer cell activity, the SRBC-specific antibody plaque-forming cell (PFC) response, thymus and spleen weight and cellularity, and thymic and splenic CD4/CD8 lymphocyte subpopulations. Exposure to PYR did not alter splenic and thymus weight or splenic cellularity. However, 20 mg PYR/kg/day decreased thymic cellularity with decreases in both CD4+/CD8+ (20 mg/kg/day) and CD4-/CD8- (10 and 20 mg/kg/day) cell types. Functional immune assays indicated that lymphocyte proliferative responses and natural killer cell activity were normal; whereas exposure to PYR significantly decreased primary IgM antibody responses to a T-cell dependent antigen at the 1, 5, 10 and 20 mg/kg treatment levels for 14 days. This is the first study to examine the immunotoxicological effects of PYR and demonstrate that this compound selectively suppresses humoral antibody responses.
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Affiliation(s)
- M M Peden-Adams
- Department of Rheumatology and Immunology, Medical University of South Carolina, Charleston, South Carolina 29412, USA.
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Sogorb MA, Vilanova E, Carrera V. Future applications of phosphotriesterases in the prophylaxis and treatment of organophosporus insecticide and nerve agent poisonings. Toxicol Lett 2004; 151:219-33. [PMID: 15177657 DOI: 10.1016/j.toxlet.2004.01.022] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2004] [Revised: 01/28/2004] [Accepted: 01/29/2004] [Indexed: 12/23/2022]
Abstract
Organophosphorus compounds (OPs) are being used as insecticides and warfare agents. OP insecticides represent an important problem of public health, causing around 200,000 deaths annually. The World Health Organization has pointed to the necessity to introduce new medical practices that improve the results of classical treatments. Many studies have shown that the administration of phosphotriesterases (enzymes that detoxify OPs through hydrolysis) is a promising treatment of persons poisoned with OPs. Such an enzyme-based treatment might introduce important improvements in the treatment of patients having ingested large amounts of OPs. Phosphotriesterases might also be suitable for prophylactic treatment of persons at risk to be severely exposed. The new experimental treatments do not exhibit the intrinsic neurotoxicity of the classical prophylaxis based on carbamates and antimuscarinic drugs. Experimental data suggest that might be time to initiate clinical trials in order to study the efficacy of phosphotriesterases in the therapy and prophylaxis of OP intoxication.
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Affiliation(s)
- Miguel A Sogorb
- División de Toxicología, Instituto de Bioingeniería, Universidad Miguel Hernández, Avenida de la Universidad s/n, 03202 Elche, Spain.
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