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Treatment and Management of Disorders of Neuromuscular Hyperexcitability and Periodic Paralysis. Neuromuscul Disord 2022. [DOI: 10.1016/b978-0-323-71317-7.00018-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Zakharova MN, Bakulin IS, Abramova AA. Toxic Damage to Motor Neurons. NEUROCHEM J+ 2021. [DOI: 10.1134/s1819712421040164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abstract—Amyotrophic lateral sclerosis (ALS) is a multifactor disease in the development of which both genetic and environmental factors play a role. Specifically, the effects of organic and inorganic toxic substances can result in an increased risk of ALS development and the acceleration of disease progression. It was described that some toxins can induce potentially curable ALS-like syndromes. In this case, the specific treatment for the prevention of the effects of the toxic factor may result in positive clinical dynamics. In this article, we review the main types of toxins that can damage motor neurons in the brain and spinal cord leading to the development of the clinical manifestation of ALS, briefly present historical data on studies on the role of toxic substances, and describe the main mechanisms of the pathogenesis of motor neuron disease associated with their action.
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Abstract
Mercury (Hg) exists in the environment as inorganic (metallic Hg vapor, mercurous and mercuric salts) or organic (bonded to a structure containing carbon atoms) forms. Neurotoxic effect of Hg is known for years. While the organic form (methylmercury (meHg)) led to the Minamata incidence in Japan and "wonder-wheat" disaster in Iraq, the "mad hatters" and "Danbury shakes" were related to the inorganic elemental form (Hg vapor). Human exposure to toxic Hg continues in the modern world to a large extent by artisanal gold mining, biomass combustion, chloralkali production, and indigenous medicine use to name a few. Heavy industrial use of Hg contaminates air and landfills, affecting the aquatic ecosystem and marine food chain. A detailed social and occupational history with a high index of clinical suspicion is required to not miss this toxic etiology for movement disorders like ataxia, tremor, or myoclonus. In this review, we have discussed the past and present global health impact of Hg from a movement disorder perspective. The connection of Hg with neurodegeneration and autoimmunity has been highlighted. We have also discussed the role of chelating agents and the preventive strategies to combat the neurotoxic effects of Hg in the modern world.
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Demystifying the spontaneous phenomena of motor hyperexcitability. Clin Neurophysiol 2021; 132:1830-1844. [PMID: 34130251 DOI: 10.1016/j.clinph.2021.03.053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/18/2021] [Accepted: 03/29/2021] [Indexed: 10/21/2022]
Abstract
Possessing a discrete functional repertoire, the anterior horn cell can be in one of two electrophysiological states: on or off. Usually under tight regulatory control by the central nervous system, a hierarchical network of these specialist neurons ensures muscular strength is coordinated, gradated and adaptable. However, spontaneous activation of these cells and their axons can result in abnormal muscular twitching. The muscular twitch is the common building block of several distinct clinical patterns, namely fasciculation, myokymia and neuromyotonia. When attempting to distinguish these entities electromyographically, their unique temporal and morphological profiles must be appreciated. Detection and quantification of burst duration, firing frequency, multiplet patterns and amplitude are informative. A common feature is their persistence during sleep. In this review, we explain the accepted terminology used to describe the spontaneous phenomena of motor hyperexcitability, highlighting potential pitfalls amidst a bemusing and complex collection of overlapping terms. We outline the relevance of these findings within the context of disease, principally amyotrophic lateral sclerosis, Isaacs syndrome and Morvan syndrome. In addition, we highlight the use of high-density surface electromyography, suggesting that more widespread use of this non-invasive technique is likely to provide an enhanced understanding of these motor hyperexcitability syndromes.
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How Occupational Mercury Neurotoxicity Is Affected by Genetic Factors. A Systematic Review. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10217706] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Occupational exposure to elemental mercury still represents a significant risk in the workplace. The sensitivity of the exposed subjects varies considerably. This study aims to summarize the literature on the role of genetic factors in occupationally exposed cohorts. A systematic search of the literature was carried out on PubMed Central (PMC), MEDLINE, and Google Scholar databases in accordance with the “Preferred Reporting Items for Systematic reviews and Meta-Analyses” (PRISMA) guidelines, from 1946 to July 2020. Ten cross-sectional studies were included in the review. All studies referred to the polymorphisms that can favour some neurotoxic effects of the metal in occupational cohorts. Some genetic variants may be associated with an increase in the occupational effects of mercury. Given the limited evidence, genetic screening of all mercury-exposed workers is not recommended. However, a personalized search for polymorphisms could be taken into consideration if exposed workers report early neurotoxic symptoms.
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Immune-associated neuromyotonia syndrome following mercury poisoning. Neurol Sci 2020; 42:1583-1586. [DOI: 10.1007/s10072-020-04831-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 10/13/2020] [Indexed: 11/24/2022]
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Pérez CA, Shah EG, Butler IJ. Mercury-induced autoimmunity: Report of two adolescent siblings with Morvan syndrome "plus" and review of the literature. J Neuroimmunol 2020; 342:577197. [PMID: 32126315 DOI: 10.1016/j.jneuroim.2020.577197] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 02/08/2020] [Accepted: 02/21/2020] [Indexed: 02/06/2023]
Abstract
Heavy metal toxicity is a global health concern. Mercury intoxication has been implicated in the etiology and pathogenesis of autoimmune disease, including Morvan syndrome. We describe two siblings with overlapping features of distinct autoimmune syndromes following accidental exposure to elemental mercury. Morvan syndrome was the predominant clinical phenotype. In addition to the characteristic anti-leucine-rich glioma-inactivated protein 1 (LGI1) and anti-contactin-associated protein-like 2 (Caspr2) autoantibodies, glutamic acid decarboxylase 65-kilodalton isoform (GAD65), and N-type and P/Q-type voltage-gated calcium channel (VGCC) antibodies were detected. Treatment with chelation therapy, glucocorticoids, and intravenous immunoglobulin was unsuccessful, but complete resolution of symptoms was achieved following treatment with rituximab. Herein, we perform an extensive review of the literature with a focus on the emerging concepts of mercury-induced autoimmunity and the role of mercury in the etiopathogenesis of autoimmune diseases of the nervous system.
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Affiliation(s)
- Carlos A Pérez
- Division of Multiple Sclerosis and Neuroimmunology, Department of Neurology, University of Texas Health Science Center at Houston, Houston, TX, USA.
| | - Ekta G Shah
- Division of Child and Adolescent Neurology, Department of Pediatrics, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Ian J Butler
- Division of Child and Adolescent Neurology, Department of Pediatrics, University of Texas Health Science Center at Houston, Houston, TX, USA
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Mohanakkannan S, Perumal SR, Velayudham S, Jeyaraj KM, Arunan S. A Case of Morvan's Syndrome Associated with Heavy Metal Poisoning after Ayurvedic Drug Intake. J Neurosci Rural Pract 2019; 9:431-433. [PMID: 30069108 PMCID: PMC6050783 DOI: 10.4103/jnrp.jnrp_555_17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Morvan's syndrome is an autoimmune disorder of peripheral and central nervous system mediated by VGKC antibody. Here we report a case of Morvans syndrome who presented 1 month after ayurvedic drug intake. She presented with symptoms of peripheral nerve hyperexcitablity and autoimmune testing revealed positive result for VGKC antibody. Heavy metals level was also significantly raised. She improved after a course of steroids. This case report tries to highlight the association of VGKC mediated Morvans syndrome with heavy metal poisoning and its incidental occurence after Ayurvedic drug intake.
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Affiliation(s)
- S Mohanakkannan
- Department of Neurology, Stanley Medical College and Hospital, Chennai, Tamil Nadu, India
| | - Sowmini R Perumal
- Department of Neurology, Stanley Medical College and Hospital, Chennai, Tamil Nadu, India
| | - Sakthi Velayudham
- Department of Neurology, Stanley Medical College and Hospital, Chennai, Tamil Nadu, India
| | - K Malcolm Jeyaraj
- Department of Neurology, Stanley Medical College and Hospital, Chennai, Tamil Nadu, India
| | - S Arunan
- Department of Neurology, Stanley Medical College and Hospital, Chennai, Tamil Nadu, India
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Exposure routes and health effects of heavy metals on children. Biometals 2019; 32:563-573. [DOI: 10.1007/s10534-019-00193-5] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Accepted: 03/22/2019] [Indexed: 02/07/2023]
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Abstract
Neuromyotonic and myokymic discharges are abnormal electrical muscular discharges caused by ectopic discharges from motor axons and represent the hallmarks of peripheral nerve hyperexcitability. Neuromyotonic discharges are specific for peripheral nerve hyperexcitability syndromes, whereas myokymic discharges may occur either focally or in a more generalized fashion in many other peripheral nerve disorders. Isaacs syndrome and Morvan syndrome are rare acquired peripheral nerve hyperexcitability disorders that share common clinical features and are often associated with elevated voltage-gated potassium channel-complex antibodies. Central nervous system symptomatology is more common in Morvan syndrome, which also overlaps with limbic encephalitis. Cramp-fasciculation syndrome, a more common syndrome, may represent a milder form of peripheral nerve hyperexcitability. Peripheral nerve hyperexcitability syndromes should be distinguished from stiff person syndrome, myotonic disorders, and rippling muscle disease. When severe, Isaacs syndrome and Morvan syndrome may be disabling but often respond to membrane-stabilizing drugs and immunomodulatory treatments. The electrophysiologic features of these disorders are described.
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Affiliation(s)
- Bashar Katirji
- Neuromuscular Center and EMG Laboratory, Neurological Institute, University Hospitals Cleveland Medical Center, Case Western Reserve University, Cleveland, OH, United States.
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Wang MD, Little J, Gomes J, Cashman NR, Krewski D. Identification of risk factors associated with onset and progression of amyotrophic lateral sclerosis using systematic review and meta-analysis. Neurotoxicology 2017; 61:101-130. [DOI: 10.1016/j.neuro.2016.06.015] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 06/29/2016] [Indexed: 12/11/2022]
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Park JH, Byun JY, Yim SY, Kim MG. A Localized Surface Plasmon Resonance (LSPR)-based, simple, receptor-free and regeneratable Hg(2+) detection system. JOURNAL OF HAZARDOUS MATERIALS 2016; 307:137-144. [PMID: 26780697 DOI: 10.1016/j.jhazmat.2015.12.040] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 12/15/2015] [Accepted: 12/21/2015] [Indexed: 06/05/2023]
Abstract
A simple, receptor-free and regeneratable Hg(2+) sensor, which utilizes localized surface plasmon resonance (LSPR) shifts of a gold nanorod (GNR), has been developed. Precipitation induced by coordination of Hg(2+) to citrate alters the local refractive index (RI) around the GNR surface on glass slide, promoting a red-shift in its LSPR absorption peak. This phenomenon is used to design a sensor that enables quantitative detection of Hg(2+) in the 1nM to 1mM concentration range with good linearity (0.9507 correlation coefficient) and limit of detection (LOD) is reached to 0.38nM. A high selectivity of this sensor for Hg(2+) is demonstrated by the specific LSPR red-shift of 27.67nm promoted by Hg(2+) in comparison to those caused by other metal ions. In addition, the reusability of the new sensor chip is shown by its successful reuse eight-times following successive washing/precipitation steps. Lastly, the sensor displays excellent recoveries in spiking test with real water samples, such as tap water, lake and river. The simple combination of precipitation of Hg(2+)-citrate complex and the LSPR red-shift has led to the design of a novel sensing strategy for Hg(2+) detection.
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Affiliation(s)
- Jin-Ho Park
- Department of Chemistry, School of Physics and Chemistry, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, Republic of Korea
| | - Ju-Young Byun
- Department of Chemistry, School of Physics and Chemistry, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, Republic of Korea
| | - Sang-Youp Yim
- Advanced Photonics Research Institute, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, Republic of Korea
| | - Min-Gon Kim
- Department of Chemistry, School of Physics and Chemistry, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, Republic of Korea; Advanced Photonics Research Institute, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, Republic of Korea.
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