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Tsujino A, Nagaoka A, Yoshimura S. Response to letter to Editor. J Neurol Sci 2023; 445:120541. [PMID: 36621039 DOI: 10.1016/j.jns.2023.120541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 01/02/2023] [Indexed: 01/06/2023]
Affiliation(s)
- Akira Tsujino
- Department of Clinical Neuroscience, Unit of Clinical Medicine, Nagasaki University Graduate School of Biomedical Sciences, Department of Neurology and Strokology, Nagasaki University Hospital, Japan.
| | - Atsushi Nagaoka
- Department of Clinical Neuroscience, Unit of Clinical Medicine, Nagasaki University Graduate School of Biomedical Sciences, Department of Neurology and Strokology, Nagasaki University Hospital, Japan
| | - Shunsuke Yoshimura
- Department of Clinical Neuroscience, Unit of Clinical Medicine, Nagasaki University Graduate School of Biomedical Sciences, Department of Neurology and Strokology, Nagasaki University Hospital, Japan
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Nagaoka A, Tsujino A, Shiraishi H, Kanamoto T, Shima T, Yoshimura S, Miyazaki T, Tateishi Y, Tsujihata M, Motomura M, Maxwell S, Higuchi O, Beeson D, Vincent A. Motor end-plate analysis to diagnose immune-mediated myasthenia gravis in seronegative patients. J Neurol Sci 2022; 443:120494. [PMID: 36403297 DOI: 10.1016/j.jns.2022.120494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 11/08/2022] [Accepted: 11/10/2022] [Indexed: 11/16/2022]
Abstract
This study aimed to evaluate the diagnostic usefulness of motor end-plate (MEP) analysis along with clustered acetylcholine receptor (AChR) antibody (Ab) assays in patients with myasthenia-like symptoms but negative routine AChR and muscle-specific kinase (MuSK) Ab tests. MEP analysis of muscle biopsies of the biceps brachii was performed in 20 patients to try to differentiate between those with or without immune-mediated myasthenia gravis (MG). Using a quantitative method, complement C3 deposition and AChR densities in MEPs were examined. Independently, cell-based assays were used to detect serum clustered-AChR Abs. Only five of 20 patients had complement deposition at MEPs; four of these patients had reduced AChR densities similar to those in patients with typical AChR Ab positive MG, and distinct from those in the remaining 15 patients. Two of the four serum samples from these patients had clustered-AChR Abs. All complement-positive patients were considered as having immune-mediated MG and improved with appropriate treatments; although one patient presented with MG 3 years later, the remaining patients had other diagnoses during over 10 years of follow-up. These results suggest the usefulness of MEP analysis of muscle biopsies in diagnosing immune-mediated MG in seronegative patients with myasthenia-like symptoms but, due to the invasiveness of the muscle biopsy procedure, clustered AChR Abs should, if possible, be tested first.
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Affiliation(s)
- Atsushi Nagaoka
- Department of Clinical Neuroscience, Unit of Clinical Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki City, Japan.
| | - Akira Tsujino
- Department of Clinical Neuroscience, Unit of Clinical Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki City, Japan.
| | - Hirokazu Shiraishi
- Department of Neurology and Strokology, Nagasaki University Hospital, Nagasaki City, Japan
| | - Tadashi Kanamoto
- Department of Neurology and Strokology, Nagasaki University Hospital, Nagasaki City, Japan
| | - Tomoaki Shima
- Department of Neurology and Strokology, Nagasaki University Hospital, Nagasaki City, Japan.
| | - Shunsuke Yoshimura
- Department of Neurology and Strokology, Nagasaki University Hospital, Nagasaki City, Japan.
| | - Teiichiro Miyazaki
- Department of Neurology and Strokology, Nagasaki University Hospital, Nagasaki City, Japan.
| | - Yohei Tateishi
- Department of Neurology and Strokology, Nagasaki University Hospital, Nagasaki City, Japan.
| | | | - Masakatsu Motomura
- Medical Electronic Course, Nagasaki Institute of Applied Science, Nagasaki City, Japan.
| | - Susan Maxwell
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK.
| | - Osamu Higuchi
- Department of Neurology, Nagasaki Kawatana Medical Center, Nagasaki, Japan.
| | - David Beeson
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK.
| | - Angela Vincent
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK.
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Kojima Y, Shibuya K, Uzawa A, Kano H, Nakamura K, Yasuda M, Suzuki YI, Tsuneyama A, Suichi T, Ozawa Y, Misawa S, Noto YI, Mizuno T, Kuwabara S. Dispersion of mean consecutive differences in single-fiber electromyography increases diagnostic sensitivity for myasthenia gravis. Muscle Nerve 2021; 63:885-889. [PMID: 33748989 DOI: 10.1002/mus.27236] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 03/14/2021] [Accepted: 03/16/2021] [Indexed: 11/10/2022]
Abstract
INTRODUCTION In this study we aimed to investigate the dispersion of mean consecutive difference (MCD) of concentric needle jitter studies of patients with myasthenia gravis (MG) and its effect on diagnostic sensitivity for MG. METHODS One hundred fifty-three patients, including 76 patients with MG and 77 controls with possible MG who later received another diagnosis, underwent stimulated concentric needle jitter studies of the frontalis muscle. MCD mean, standard deviation (SD), and coefficient of variation (CV) were calculated. Diagnostic sensitivity and specificity were determined using receiver operating characteristic (ROC) analyses. RESULTS MG patients showed a significantly greater MCD mean (MG: control, 26.3 μs; 13.5 μs [median]; P < .0001), MCD SD (MG: control, 12.8 μs; 5.1 μs [median]; P < .0001), and MCD CV (MG: control, 46.1; 37.5 [median]; P < .001) than those without MG. An ROC curve of SD showed a large area under the curve (0.88), and a cut-off value of 7.2 μs, which was calculated by maximum Youden index, exhibited high diagnostic sensitivity (86%) for MG. Combined MCD mean, outliers, and SD criteria showed higher sensitivity (88%) than conventional criteria alone (82%), at the expense of lower specificity. Five MG patients with normal MCD mean and abnormal MCD SD had only ocular symptoms. DISCUSSION The dispersion of MCD as measured by MCD SD greater than 7.2 μs is significantly increased in patients with MG and may be a useful measure of abnormal jitter in the diagnosis of MG, especially for identifying patients with mild disease.
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Affiliation(s)
- Yuta Kojima
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan.,Department of Neurology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Kazumoto Shibuya
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Akiyuki Uzawa
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Hiroki Kano
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Keigo Nakamura
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Manato Yasuda
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Yo-Ichi Suzuki
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Atsuko Tsuneyama
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Tomoki Suichi
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Yukiko Ozawa
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Sonoko Misawa
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Yu-Ichi Noto
- Department of Neurology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Toshiki Mizuno
- Department of Neurology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Satoshi Kuwabara
- Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan
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Cetin H, Beeson D, Vincent A, Webster R. The Structure, Function, and Physiology of the Fetal and Adult Acetylcholine Receptor in Muscle. Front Mol Neurosci 2020; 13:581097. [PMID: 33013323 PMCID: PMC7506097 DOI: 10.3389/fnmol.2020.581097] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 08/13/2020] [Indexed: 12/31/2022] Open
Abstract
The neuromuscular junction (NMJ) is a highly developed synapse linking motor neuron activity with muscle contraction. A complex of molecular cascades together with the specialized NMJ architecture ensures that each action potential arriving at the motor nerve terminal is translated into an action potential in the muscle fiber. The muscle-type nicotinic acetylcholine receptor (AChR) is a key molecular component located at the postsynaptic muscle membrane responsible for the generation of the endplate potential (EPP), which usually exceeds the threshold potential necessary to activate voltage-gated sodium channels and triggers a muscle action potential. Two AChR isoforms are found in mammalian muscle. The fetal isoform is present in prenatal stages and is involved in the development of the neuromuscular system whereas the adult isoform prevails thereafter, except after denervation when the fetal form is re-expressed throughout the muscle. This review will summarize the structural and functional differences between the two isoforms and outline congenital and autoimmune myasthenic syndromes that involve the isoform specific AChR subunits.
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Affiliation(s)
- Hakan Cetin
- Department of Neurology, Medical University of Vienna, Vienna, Austria.,Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - David Beeson
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Angela Vincent
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Richard Webster
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
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Liang H, Ward WF, Jang YC, Bhattacharya A, Bokov AF, Li Y, Jernigan A, Richardson A, Van Remmen H. PGC-1α protects neurons and alters disease progression in an amyotrophic lateral sclerosis mouse model. Muscle Nerve 2011; 44:947-56. [DOI: 10.1002/mus.22217] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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de Souza PAT, Matheus SMM, Castan EP, Campos DHS, Cicogna AC, Carvalho RF, Dal-Pai-Silva M. Morphological aspects of neuromuscular junctions and gene expression of nicotinic acetylcholine receptors (nAChRs) in skeletal muscle of rats with heart failure. J Mol Histol 2011; 42:557-65. [PMID: 21928074 DOI: 10.1007/s10735-011-9354-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 08/27/2011] [Indexed: 12/19/2022]
Abstract
HF is syndrome initiated by a reduction in cardiac function and it is characterized by the activation of compensatory mechanisms. Muscular fatigue and dyspnoea are the more common symptoms in HF; these may be due in part to specific skeletal muscle myopathy characterized by reduced oxidative capacity, a shift from slow fatigue resistant type I to fast less fatigue resistant type II fibers and downregulation of myogenic regulatory factors (MRFs) gene expression that can regulate gene expression of nicotinic acetylcholine receptors (nAChRs). In chronic heart failure, skeletal muscle phenotypic changes could influence the maintenance of the neuromuscular junction morphology and nAChRs gene expression during this syndrome. Two groups of rats were studied: control (CT) and Heart Failure (HF), induced by a single intraperitoneal injection of monocrotaline (MCT). At the end of the experiment, HF was evaluated by clinical signs and animals were sacrificed. Soleus (SOL) muscles were removed and processed for morphological, morphometric and molecular NMJ analyses. Our major finding was an up-regulation in the gene expression of the alpha1 and epsilon subunits of nAChR and a spot pattern of nAChR in SOL skeletal muscle in this acute monocrotaline induced HF. Our results suggest a remodeling of nAChR alpha1 and epsilon subunit during heart failure and may provide valuable information for understanding the skeletal muscle myopathy that occurs during this syndrome.
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Bernareggi A, Reyes-Ruiz JM, Lorenzon P, Ruzzier F, Miledi R. Microtransplantation of acetylcholine receptors from normal or denervated rat skeletal muscles to frog oocytes. J Physiol 2011; 589:1133-42. [PMID: 21224230 DOI: 10.1113/jphysiol.2010.202994] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Cell membranes, carrying neurotransmitter receptors and ion channels, can be 'microtransplanted' into frog oocytes. This technique allows a direct functional characterization of the original membrane proteins, together with any associated molecules they may have, still embedded in their natural lipid environment. This approach has been previously demonstrated to be very useful to study neurotransmitter receptors and ion channels contained in cell membranes isolated from human brains. Here, we examined the possibility of using the microtransplantation method to study acetylcholine receptors from normal and denervated rat skeletal muscles. We found that the muscle membranes, carrying their fetal or adult acetylcholine receptor isoforms, could be efficiently microtransplanted to the oocyte membrane, making the oocytes become sensitive to acetylcholine. These results show that oocytes injected with skeletal muscle membranes efficiently incorporate functional acetylcholine receptors, thus making the microtransplantation approach a valuable tool to further investigate receptors and ion channels of human muscle diseases.
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Affiliation(s)
- Annalisa Bernareggi
- Department of Life Sciences, University of Trieste, Via A. Fleming 22, I-34127 Trieste, Italy.
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Nigrovic V, Amann A, Bhatt S. Myasthenia gravis and myasthenic syndrome: simulation of twitch strength with or without therapy. Muscle Nerve 2005; 32:745-50. [PMID: 16094654 DOI: 10.1002/mus.20424] [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: 11/07/2022]
Abstract
To examine the quantitative relationship between indirectly evoked twitch and decreases in the number of either postsynaptic receptors or acetylcholine molecules released by a single stimulus, we studied these variables in a computer-simulated model of neuromuscular transmission. Twitch strength decreased if the number of receptors decreased to below 30% of normal or the number of acetylcholine molecules released by a stimulus decreased to below 80%. Inhibition of acetylcholine hydrolysis to 50% restored twitch strength in the presence of a decreased number of receptors. However, twitch strength was more easily restored to normalcy by augmenting the release of acetylcholine, if the release was diminished by disease. The simulations mimic the clinically known therapeutic outcomes in certain disorders of neuromuscular transmission. These results provide useful quantitative insights into the relationship between acetylcholine receptors or the stimulus-induced release of acetylcholine and muscle function in myasthenia gravis or Lambert-Eaton myasthenic syndrome.
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Affiliation(s)
- Vladimir Nigrovic
- Department of Anesthesiology, Medical University of Ohio, 3000 Arlington Avenue, Toledo, Ohio 43614-2598, USA.
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Shiraishi H, Motomura M, Yoshimura T, Fukudome T, Fukuda T, Nakao Y, Tsujihata M, Vincent A, Eguchi K. Acetylcholine receptors loss and postsynaptic damage in MuSK antibody-positive myasthenia gravis. Ann Neurol 2005; 57:289-93. [PMID: 15668981 DOI: 10.1002/ana.20341] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Muscle-specific tyrosine kinase (MuSK) antibodies are found in some patients with "seronegative" myasthenia gravis (MG), but how they cause myasthenic symptoms is not clear. We visualized acetylcholine receptors (AChRs) and complement component 3 (C3) in muscle biopsies from 10 Japanese MG patients with MuSK antibodies, compared with 42 with AChR antibodies. The AChR density was not significantly decreased in MuSK antibody (Ab)-positive end-plates compared with AChR antibody-positive end-plates, and C3 was detected in only two of eight MuSK Ab-positive patients. MuSK antibodies do not appear to cause substantial AChR loss, complement deposition, or morphological damage. Effects on MuSK function need to be explored.
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Affiliation(s)
- Hirokazu Shiraishi
- The First Department of Internal Medicine, Graduate School of Biomedical Sciences, Nagasaki, Japan
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Gattenlöhner S, Schneider C, Thamer C, Klein R, Roggendorf W, Gohlke F, Niethammer C, Czub S, Vincent A, Müller-Hermelink HK, Marx A. Expression of foetal type acetylcholine receptor is restricted to type 1 muscle fibres in human neuromuscular disorders. Brain 2002; 125:1309-19. [PMID: 12023319 DOI: 10.1093/brain/awf136] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
In adult muscle, acetylcholine receptors (AChR) are restricted mainly to the motor endplate where the adult isoform (alphabetadeltaepsilon) is expressed. When skeletal muscle is denervated in animal models, there is atrophy of the muscle and a marked increase in expression of the AChR foetal isoform (alphabetagammadelta) containing a gamma-subunit. Similar changes in AChR expression are thought to occur in human muscle. While the role of denervation in regulating AChR gene expression has been widely studied, it has not been determined whether the transcriptional programmes responsible for defining different fibre types have an impact on the expression of AChR genes. We investigated biopsies from patients with a wide spectrum of neuromuscular diseases for expression of the AChR alpha- and gamma-subunits using RNase protection assays, alpha/gamma-duplex reverse transcriptase polymerase chain reaction, immunohistochemistry for foetal AChR and RNA in situ hybridization. Muscle from all patients with neurogenic disorders and, to a lesser extent, myogenic disorders, exhibited markedly increased transcription of the AChR gamma-subunit but, in contrast to previous animal studies, did not show increased AChR alpha-subunit. Moreover, both immunohistochemistry and RNA in situ hybridization revealed that AChR gamma-subunit hyperexpression occurred exclusively in atrophic type 1 and not in atrophic type 2 muscle fibres, irrespective of the underlying neuromuscular disease. We conclude that up-regulation of the AChR gamma-subunit in human muscle disorders is restricted to type 1 muscle fibres and, therefore, that AChR gamma-subunit expression is controlled by a muscle fibre type-restricted transcriptional programme. The factors influencing expression of this and other functional proteins should be relevant to the understanding and treatment of a range of neuromuscular disorders.
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