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1.
Int Heart J ; 65(2): 211-217, 2024.
Article in English | MEDLINE | ID: mdl-38556332

ABSTRACT

Duchenne muscular dystrophy (DMD) is an intractable X-linked myopathy caused by dystrophin gene mutations. Patients with DMD suffer from progressive muscle weakness, inevitable cardiomyopathy, increased heart rate (HR), and decreased blood pressure (BP). The aim of this study was to clarify the efficacy and tolerability of ivabradine treatment for DMD cardiomyopathy.A retrospective analysis was performed in 11 patients with DMD, who received ivabradine treatment for more than 1 year. Clinical results were analyzed before (baseline), 6 months after, and 12 months after the ivabradine administration.The initial ivabradine dose was 2.0 ± 1.2 mg/day and the final dose was 5.6 ± 4.0 mg/day. The baseline BP was 95/64 mmHg. A non-significant BP decrease to 90/57 mmHg was observed at 1 month but it recovered to 97/62 mmHg at 12 months after ivabradine administration. The baseline HR was 93 ± 6 bpm and it decreased to 74 ± 12 bpm at 6 months (P = 0.011), and to 77 ± 10 bpm at 12 months (P = 0.008). A linear correlation (y = 2.2x + 5.1) was also observed between the ivabradine dose (x mg/day) and HR decrease (y bpm). The baseline LVEF was 38 ± 12% and it significantly increased to 42 ± 9% at 6 months (P = 0.011) and to 41 ± 11% at 12 months (P = 0.038). Only 1 patient with the lowest BMI of 11.0 kg/m2 and BP of 79/58 mmHg discontinued ivabradine treatment at 6 months, while 1-year administration was well-tolerated in the other 10 patients.Ivabradine decreased HR and increased LVEF without lowering BP, suggesting it can be a treatment option for DMD cardiomyopathy.


Subject(s)
Cardiomyopathies , Muscular Dystrophy, Duchenne , Humans , Ivabradine/therapeutic use , Muscular Dystrophy, Duchenne/complications , Muscular Dystrophy, Duchenne/drug therapy , Muscular Dystrophy, Duchenne/genetics , Retrospective Studies , Cardiomyopathies/complications , Cardiomyopathies/drug therapy , Dystrophin/genetics
2.
Clin Neurophysiol ; 135: 30-36, 2022 03.
Article in English | MEDLINE | ID: mdl-35026538

ABSTRACT

OBJECTIVE: This study aimed to develop a simple and reliable technique to assess excitation-contraction (E-C) coupling for early diagnosis of critical illness myopathy (CIM). METHODS: We prospectively performed clinical and electrophysiological examinations on patients admitted to intensive care unit (ICU). In addition to full neurological examinations and routine nerve conduction study, motor related potential (MRP) was recorded using an accelerometer attached to the base of hallux after tibial nerve stimulation, and E-C coupling time (ECCT) was measured from the latency difference between soleus compound muscle action potential (CMAP) and MRP. RESULTS: Of 41 patients evaluated, 25 met the criteria for ICU-acquired weakness, 23 of whom had CIM. The time to the first electrophysiological examination (time to first test) correlated negatively with CMAP and with MRP. Conversely, a positive correlation was observed between the time to first test and ECCT. E-C coupling impairment occurred in most of our patients with CIM by the third day of ICU admission, and prolonged ECCT could be the earliest detectable abnormality. CONCLUSIONS: The ECCT measurement is an easy and reliable technique to detect reduced muscle membrane excitability in the early stage of CIM. SIGNIFICANCE: The ECCT measured by our method using an accelerometer may be a parameter that predicts the development of CIM.


Subject(s)
Excitation Contraction Coupling , Muscular Diseases/physiopathology , Accelerometry/instrumentation , Accelerometry/methods , Adult , Aged , Aged, 80 and over , Critical Illness , Early Diagnosis , Electromyography/instrumentation , Electromyography/methods , Evoked Potentials, Motor , Female , Humans , Male , Middle Aged , Muscle, Skeletal/physiopathology , Muscular Diseases/diagnosis
3.
Phys Ther Res ; 24(1): 29-34, 2021.
Article in English | MEDLINE | ID: mdl-33981525

ABSTRACT

OBJECTIVE: The aim of this study was to apply a novel method to measure excitation-contraction coupling time (ECCT) in normal soleus muscles. METHODS: We performed simultaneous recordings of soleus compound muscle action potential (CMAP) and foot movement-related potential (MRP), and measured ankle plantar flexion torque in 36 healthy subjects. We calculated ECCT and examined the relations between CMAP, MRP, ECCT and ankle plantar flexion torque. RESULTS: Statistical analyses established reference ranges (mean ± SE) for CMAP (13.4 ± 0.9 mV), MRP (5.3 ± 0.4 m/s2), ECCT (5.2 ± 0.1 ms), torque (85.9 ± 6.4 Nm) and torque/body weight (1.4 ± 0.1 Nm/kg). The torque showed a positive linear correlation with CMAP (p = 0.041) and a negative linear correlation with ECCT (p = 0.045). CONCLUSION: Soleus ECCT can be recorded easily, and is useful to assess the impairment of E-C coupling in muscles of the lower extremities.

5.
Front Neurol ; 11: 868, 2020.
Article in English | MEDLINE | ID: mdl-32982912

ABSTRACT

Treatment with oral corticosteroids at high doses with an escalation and de-escalation schedule is effective against myasthena gravis (MG). In fact, the use of corticosteroids has led to a reduction in mortality to below 10% after the 1960s. However, long-term use of oral steroids above a certain dosage level is known to cause a number of problems. In 2014, the Japanese clinical guidelines for MG proposed that the first goal in MG treatment (treatment target) should be set at minimal manifestations (MM) with oral prednisolone (PSL) 5 mg/day or below, and that treatment strategies should strive to attain this level as rapidly as possible. In 2015, a multicenter, cross-sectional study revealed that higher PSL dose and longer PSL treatment do not ensure better outcome. In the absence of good response, the PSL dose should be decreased by combining with modalities such as plasma exchange/plasmapheresis and intravenous immunoglobulin (fast-acting treatments). In 2018, we conducted a multicenter, cross-sectional study in a large population of Japanese patients with generalized MG, aiming to elucidate the correlation between oral PSL regimens and achievement of treatment goals. The ORs for low vs. high dose to achieve treatment goals at 1, 2, and 3 years were 10.4, 2.75, and 1.86, respectively, whereas the corresponding ORs for low vs. medium dose were 13.4, 3.99, and 4.92. Early combination with fast-acting therapy (OR 2.19 at 2 years, 2.11 at 3 years) or combination with calcineurin inhibitors (OR 2.09 at 2 years, 2.36 at 3 years) were also positively associated with achieving treatment goals. These results indicate that early combination of low-dose PSL regimens with other therapies is the key for early achievement of treatment goals in generalized MG. However, even with this regimen, ~35% of patients did not achieve the treatment target after 3 years. These results suggest the limitation of the current oral corticosteroid therapy. We need to develop new treatment options to increase the rate of satisfactory outcome.

6.
Intern Med ; 59(5): 705-710, 2020 Mar 01.
Article in English | MEDLINE | ID: mdl-31735796

ABSTRACT

Rheumatoid vasculitis (RV) usually occurs in patients with refractory rheumatoid arthritis (RA). An 80-year-old woman was transferred to our hospital because of muscle weakness and paresthesia in all 4 limbs. She had been diagnosed with RA 30 years ago and achieved sustained clinical remission. At presentation, polyarthritis and drop foot were observed, and rheumatoid factor was prominently elevated. A peripheral nerve conduction test revealed mononeuritis multiplex in her limbs. We suspected that RV had developed rapidly despite RA having been stable for many years and started immunosuppression therapy with steroids combined with azathioprine. The treatment prevented worsening of muscle weakness and paresthesia.


Subject(s)
Arthritis, Rheumatoid/complications , Mononeuropathies/etiology , Rheumatoid Vasculitis/etiology , Aged, 80 and over , Arthritis, Rheumatoid/drug therapy , Female , Humans , Immunosuppressive Agents/therapeutic use , Mononeuropathies/drug therapy , Rheumatoid Factor/blood , Rheumatoid Vasculitis/drug therapy
7.
J Neurol Sci ; 407: 116419, 2019 Dec 15.
Article in English | MEDLINE | ID: mdl-31698177

ABSTRACT

The terminal complement inhibitor eculizumab was shown to improve myasthenia gravis-related symptoms in the 26-week, phase 3, randomized, double-blind, placebo-controlled REGAIN study (NCT01997229). In this 52-week sub-analysis of the open-label extension of REGAIN (NCT02301624), eculizumab's efficacy and safety were assessed in 11 Japanese and 88 Caucasian patients with anti-acetylcholine receptor antibody-positive refractory generalized myasthenia gravis. For patients who had received placebo during REGAIN, treatment with open-label eculizumab resulted in generally similar outcomes in the Japanese and Caucasian populations. Rapid improvements were maintained for 52 weeks, assessed by change in score from open-label extension baseline to week 52 (mean [standard error]) using the following scales (in Japanese and Caucasian patients, respectively): Myasthenia Gravis Activities of Daily Living (-2.4 [1.34] and - 3.3 [0.65]); Quantitative Myasthenia Gravis (-2.9 [1.98] and - 4.3 [0.79]); Myasthenia Gravis Composite (-4.5 [2.63] and - 4.9 [1.19]); and Myasthenia Gravis Quality of Life 15-item questionnaire (-8.6 [5.68] and - 6.5 [1.93]). Overall, the safety of eculizumab was consistent with its known safety profile. In this interim sub-analysis, the efficacy and safety of eculizumab in Japanese and Caucasian patients were generally similar, and consistent with the overall REGAIN population.


Subject(s)
Antibodies, Monoclonal, Humanized/therapeutic use , Complement Inactivating Agents/therapeutic use , Myasthenia Gravis/drug therapy , Adult , Aged , Antibodies, Monoclonal, Humanized/adverse effects , Asian People , Complement Inactivating Agents/adverse effects , Female , Humans , Japan , Male , Middle Aged , Treatment Outcome
8.
J Diabetes Investig ; 10(2): 466-474, 2019 Mar.
Article in English | MEDLINE | ID: mdl-29975462

ABSTRACT

AIMS/INTRODUCTION: Diabetic polyneuropathy is one of the most frequent diabetic complications, and impairs patients' quality of life. We evaluated the efficacy and safety of ranirestat (40 mg/day) in patients with diabetic polyneuropathy. MATERIALS AND METHODS: This was a multicenter, placebo-controlled, randomized double-blind, parallel-group, phase III study in which 557 patients were randomly assigned to either the ranirestat or placebo group and assessed for 52 weeks. The co-primary end-points were the changes in tibial motor nerve conduction velocity and total modified Toronto Clinical Neuropathy Score as a measure of clinical symptoms. RESULTS: There was a significant increase in tibial motor nerve conduction velocity in the ranirestat group compared with the placebo group. The difference between groups in the change at last observation was 0.52 m/s (P = 0.021). Increases in nerve conduction velocity in the ranirestat group were found not only in the tibial motor nerves, but also in the median motor nerves, proximal median sensory nerves and distal median sensory nerves. No significant differences in modified Toronto Clinical Neuropathy Score or safety parameters were found between the two groups. CONCLUSIONS: Ranirestat (40 mg/day) was well tolerated and improved nerve conduction velocity. Regarding symptoms and signs, no detectable benefits over the placebo were observed in the ranirestat group during the 52 weeks of treatment.


Subject(s)
Aldehyde Reductase/antagonists & inhibitors , Diabetic Neuropathies/drug therapy , Enzyme Inhibitors/therapeutic use , Neural Conduction/drug effects , Pyrazines/therapeutic use , Quality of Life , Spiro Compounds/therapeutic use , Adult , Aged , Diabetic Neuropathies/epidemiology , Double-Blind Method , Female , Follow-Up Studies , Humans , Japan/epidemiology , Male , Middle Aged , Prognosis , Young Adult
9.
Front Physiol ; 9: 1111, 2018.
Article in English | MEDLINE | ID: mdl-30147660

ABSTRACT

Severe muscle weakness concomitant with preferential depletion of myosin has been observed in several pathological conditions. Here, we used the steroid-denervation (S-D) rat model, which shows dramatic decrease in myosin content and force production, to test whether electrical stimulation (ES) treatment can prevent these deleterious changes. S-D was induced by cutting the sciatic nerve and subsequent daily injection of dexamethasone for 7 days. For ES treatment, plantarflexor muscles were electrically stimulated to produce four sets of five isometric contractions each day. Plantarflexor in situ isometric torque, muscle weight, skinned muscle fiber force, and protein and mRNA expression were measured after the intervention period. ES treatment partly prevented the S-D-induced decreases in plantarflexor in situ isometric torque and muscle weight. ES treatment fully prevented S-D-induced decreases in skinned fiber force and ratio of myosin heavy chain (MyHC) to actin, as well as increases in the reactive oxygen/nitrogen species-generating enzymes NADPH oxidase (NOX) 2 and 4, phosphorylation of p38 MAPK, mRNA expression of the muscle-specific ubiquitin ligases muscle ring finger-1 (MuRF-1) and atrogin-1, and autolyzed active calpain-1. Thus, ES treatment is an effective way to prevent muscle impairments associated with loss of myosin.

10.
Ann N Y Acad Sci ; 1413(1): 35-40, 2018 02.
Article in English | MEDLINE | ID: mdl-29377151

ABSTRACT

According to the 2014 Japanese clinical guidelines for myasthenia gravis, the most important priority in treatment is maintaining patients' health-related quality of life. Therefore, the initial treatment goal is defined as maintaining a postintervention status of minimal manifestations or better (according to the Myasthenia Gravis Foundation of America classification) with an oral prednisolone dose of 5 mg/day or less. Every effort should be made to attain this level as rapidly as possible. To achieve this goal, the guidelines recommend minimizing the oral prednisolone dose, starting calcineurin inhibitors early in the course of treatment, using intravenous methylprednisolone infusion judiciously (often combined with plasma exchange/plasmapheresis or intravenous immunoglobulin), and effectively treating patients with an early, fast-acting treatment strategy. The early, fast-acting treatment strategy enables more frequent and earlier attainment of the initial goal than other strategies. Thymectomy is considered an option for treating nonthymomatous early-onset myasthenia gravis in patients with antiacetylcholine receptor antibodies and thymic hyperplasia in the early stages of the disease.


Subject(s)
Calcineurin Inhibitors/therapeutic use , Cholinergic Antagonists/therapeutic use , Immunosuppressive Agents/therapeutic use , Methylprednisolone/therapeutic use , Myasthenia Gravis/drug therapy , Prednisolone/therapeutic use , Quality of Life , Antibodies/immunology , Antibodies/therapeutic use , Humans , Immunosuppressive Agents/administration & dosage , Japan , Methylprednisolone/administration & dosage , Prednisolone/administration & dosage , Receptors, Cholinergic/immunology , Thymectomy
11.
J Neurol Neurosurg Psychiatry ; 89(5): 513-517, 2018 05.
Article in English | MEDLINE | ID: mdl-29175893

ABSTRACT

OBJECTIVE: We examined the correlation between the dosing regimen of oral prednisolone (PSL) and the achievement of minimal manifestation status or better on PSL ≤5 mg/day lasting >6 months (the treatment target) in patients with generalised myasthenia gravis (MG). METHODS: We classified 590 patients with generalised MG into high-dose (n=237), intermediate-dose (n=187) and low-dose (n=166) groups based on the oral PSL dosing regimen, and compared the clinical characteristics, previous treatments other than PSL and prognosis between three groups. The effect of oral PSL dosing regimen on the achievement of the treatment target was followed for 3 years of treatment. RESULTS: To achieve the treatment target, ORs for low-dose versus high-dose regimen were 10.4 (P<0.0001) after 1 year of treatment, 2.75 (P=0.007) after 2 years and 1.86 (P=0.15) after 3 years; and those for low-dose versus intermediate-dose regimen were 13.4 (P<0.0001) after 1 year, 3.99 (P=0.0003) after 2 years and 4.92 (P=0.0004) after 3 years. Early combined use of fast-acting treatment (OR: 2.19 after 2 years, P=0.02; OR: 2.11 after 3 years, P=0.04) or calcineurin inhibitors (OR: 2.09 after 2 years, P=0.03; OR: 2.36 after 3 years, P=0.02) was associated positively with achievement of treatment target. CONCLUSION: A low-dose PSL regimen with early combination of other treatment options may ensure earlier achievement of the treatment target in generalised MG.


Subject(s)
Myasthenia Gravis/drug therapy , Prednisolone/therapeutic use , Administration, Oral , Adolescent , Adult , Aged , Aged, 80 and over , Cross-Sectional Studies , Dose-Response Relationship, Drug , Drug Therapy, Combination , Female , Glucocorticoids/therapeutic use , Humans , Japan , Male , Middle Aged , Prednisolone/administration & dosage , Prognosis , Treatment Outcome , Young Adult
12.
Clin Neurophysiol ; 128(11): 2309-2317, 2017 11.
Article in English | MEDLINE | ID: mdl-29040921

ABSTRACT

OBJECTIVE: The ice-pack test is a convenient diagnostic testing procedure for myasthenia gravis (MG). We investigated the underlying mechanism of the ice-pack test performed on bilateral masseters. METHODS: We performed trigeminal repetitive nerve stimulation (RNS), excitation-contraction (E-C) coupling assessment (Imai's method) and bite force measurement before and after cooling of the masseters in MG patients and normal controls. After placing the ice-pack on the masseters for 3min, serial recordings of the three tests were performed at various time intervals during 10min after cooling. RESULTS: The bite force increased significantly after cooling in ice-pack-positive MG patients. The acceleration and acceleration ratio (acceleration at a given time to baseline acceleration) of jaw movement increased significantly after cooling of the masseters in ice-pack-positive MG patients compared to ice-pack-negative patients and normal controls. The prolonged effect of cooling continued until the end of recording even though decremental response to RNS had returned to baseline value. CONCLUSIONS: Cooling of myasthenic muscle may induce two effects. One is relatively short effect on electrical synaptic transmission at the endplate, and another is prolonged effect on E-C coupling in the muscle. SIGNIFICANCE: The ice-pack test induces a prolonged effect of ameliorating impaired E-C coupling in MG.


Subject(s)
Excitation Contraction Coupling/physiology , Fasciculation/physiopathology , Masseter Muscle/physiopathology , Myasthenia Gravis/physiopathology , Adult , Aged , Bite Force , Cold Temperature , Female , Humans , Ice , Male , Middle Aged
13.
BMJ Open ; 7(2): e013278, 2017 02 23.
Article in English | MEDLINE | ID: mdl-28235967

ABSTRACT

OBJECTIVES: To clarify the social disadvantages associated with myasthenia gravis (MG) and examine associations with its disease and treatment. DESIGN: Cross-sectional study. SETTING AND PARTICIPANTS: We evaluated 917 consecutive cases of established MG seen at 13 neurological centres in Japan over a short duration. OUTCOME MEASURES: All patients completed a questionnaire on social disadvantages resulting from MG and its treatment and a 15-item MG-specific quality of life scale at study entry. Clinical severity at the worst condition was graded according to the MG Foundation of America classification, and that at the current condition was determined according to the quantitative MG score and MG composite. Maximum dose and duration of dose ≥20 mg/day of oral prednisolone during the disease course were obtained from the patients' medical records. Achievement of the treatment target (minimal manifestation status with prednisolone at ≤5 mg/day) was determined at 1, 2 and 4 years after starting treatment and at study entry. RESULTS: We found that 27.2% of the patients had experienced unemployment, 4.1% had been unwillingly transferred and 35.9% had experienced a decrease in income, 47.1% of whom reported that the decrease was ≥50% of their previous total income. In addition, 49.0% of the patients reported feeling reduced social positivity. Factors promoting social disadvantages were severity of illness, dose and duration of prednisolone, long-term treatment, and a depressive state and change in appearance after treatment with oral steroids. Early achievement of the treatment target was a major inhibiting factor. CONCLUSIONS: Patients with MG often experience unemployment, unwilling job transfers and a decrease in income. In addition, many patients report feeling reduced social positivity. To inhibit the social disadvantages associated with MG and its treatment, greater focus needs to be placed on helping patients with MG resume a normal lifestyle as soon as possible by achieving the treatment target.


Subject(s)
Depression/epidemiology , Income/statistics & numerical data , Myasthenia Gravis/psychology , Unemployment/statistics & numerical data , Adult , Aged , Aged, 80 and over , Cross-Sectional Studies , Female , Humans , Japan , Logistic Models , Male , Middle Aged , Multivariate Analysis , Myasthenia Gravis/drug therapy , Prednisolone/administration & dosage , Psychiatric Status Rating Scales , Quality of Life , Severity of Illness Index , Social Support , Surveys and Questionnaires , Young Adult
14.
Muscle Nerve ; 55(6): 794-801, 2017 06.
Article in English | MEDLINE | ID: mdl-27603432

ABSTRACT

INTRODUCTION: In this study we sought to clarify the effects of early fast-acting treatment (EFT) strategies on the time course for achieving the treatment target in generalized myasthenia gravis (MG). METHODS: This retrospective study of 923 consecutive MG patients analyzed 688 generalized MG patients who had received immunotherapy during the disease course. The time to first achieve minimal manifestations (MM) or better while receiving prednisolone at ≤5 mg/day for ≥6 months (MM-or-better-5mg) up to 120 months after starting immunotherapy was compared between EFT and non-EFT patients. RESULTS: Achievement of MM-or-better-5mg was more frequent and earlier in the EFT group (P = 0.0004, Wilcoxon test; P = 0.0001, log-rank test). Multivariate Cox regression analysis calculated a hazard ratio of 1.98 (P < 0.0001) for utilization of EFT. Dosing regimens of oral steroids in EFT produced no differences in the time course. CONCLUSIONS: EFT strategies are advantageous for early achievement of MM-or-better-5mg. Muscle Nerve 55: 794-801, 2017.


Subject(s)
Anti-Inflammatory Agents/therapeutic use , Immunotherapy/methods , Myasthenia Gravis/drug therapy , Prednisolone/therapeutic use , Adult , Aged , Cohort Studies , Female , Humans , Japan , Male , Middle Aged , Statistics, Nonparametric , Time Factors
15.
BMC Neurol ; 16(1): 225, 2016 Nov 17.
Article in English | MEDLINE | ID: mdl-27855632

ABSTRACT

BACKGROUND: We have previously reported using two-step cluster analysis to classify myasthenia gravis (MG) patients into the following five subtypes: ocular MG; thymoma-associated MG; MG with thymic hyperplasia; anti-acetylcholine receptor antibody (AChR-Ab)-negative MG; and AChR-Ab-positive MG without thymic abnormalities. The objectives of the present study were to examine the reproducibility of this five-subtype classification using a new data set of MG patients and to identify additional characteristics of these subtypes, particularly in regard to response to treatment. METHODS: A total of 923 consecutive MG patients underwent two-step cluster analysis for the classification of subtypes. The variables used for classification were sex, age of onset, disease duration, presence of thymoma or thymic hyperplasia, positivity for AChR-Ab or anti-muscle-specific tyrosine kinase antibody, positivity for other concurrent autoantibodies, and disease condition at worst and current. The period from the start of treatment until the achievement of minimal manifestation status (early-stage response) was determined and then compared between subtypes using Kaplan-Meier analysis and the log-rank test. In addition, between subtypes, the rate of the number of patients who maintained minimal manifestations during the study period/that of patients who only achieved the status once (stability of improved status) was compared. RESULTS: As a result of two-step cluster analysis, 923 MG patients were classified into five subtypes as follows: ocular MG (AChR-Ab-positivity, 77%; histogram of onset age, skewed to older age); thymoma-associated MG (100%; normal distribution); MG with thymic hyperplasia (89%; skewed to younger age); AChR-Ab-negative MG (0%; normal distribution); and AChR-Ab-positive MG without thymic abnormalities (100%, skewed to older age). Furthermore, patients classified as ocular MG showed the best early-stage response to treatment and stability of improved status, followed by those classified as thymoma-associated MG and AChR-Ab-positive MG without thymic abnormalities; by contrast, those classified as AChR-Ab-negative MG showed the worst early-stage response to treatment and stability of improved status. CONCLUSIONS: Differences were seen between the five subtypes in demographic characteristics, clinical severity, and therapeutic response. Our five-subtype classification approach would be beneficial not only to elucidate disease subtypes, but also to plan treatment strategies for individual MG patients.


Subject(s)
Myasthenia Gravis/mortality , Severity of Illness Index , Adolescent , Adult , Aged , Aged, 80 and over , Child , Cluster Analysis , Female , Humans , Japan , Kaplan-Meier Estimate , Male , Middle Aged , Myasthenia Gravis/complications , Myasthenia Gravis/drug therapy , Myasthenia Gravis/immunology , Myasthenia Gravis/pathology , Reproducibility of Results , Thymoma/complications , Thymus Neoplasms/complications , Young Adult
16.
Clin Neurophysiol ; 127(2): 1689-1693, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26547355

ABSTRACT

OBJECTIVE: The aim of this study was to evaluate post-tetanic potentiation of muscle twitch in myasthenia gravis (MG). METHODS: Post-tetanic potentiation was evaluated by recording the compound muscle action potential (CMAP) of abductor pollicis brevis and movement-related potential (MRP) of the thumb using an accelerometer after tetanic stimulation of the median nerve at the wrist. After baseline recording, tetanic stimulation was delivered to the median nerve at a frequency of 10 Hz for 10s. The CMAP and MRP were successively recorded at baseline and at 5, 10, 30, 60, 90 and 120 s after tetanic stimulation. The chronological changes of CMAPs and MRPs were recorded bilaterally in 11 patients with MG, 9 patients with myopathies (disease controls), and 25 healthy control subjects. RESULTS: Maximal acceleration of MRP was significantly elevated during 10s after tetanic stimulation without any CMAP changes in all groups. However, statistical analysis detected a significant decrease in post-tetanic potentiation of maximal acceleration of MRP in MG patients only compared to healthy controls, but not in myopathy patients, which may imply impairment of excitation-contraction coupling in MG. CONCLUSIONS: Post-tetanic potentiation of muscle twitch is significantly diminished in MG, suggesting impaired excitation-contraction coupling. SIGNIFICANCE: Measurement of post-tetanic potentiation using an accelerometer is a simple and sensitive method to detect impairment of excitation-contraction coupling in MG.


Subject(s)
Action Potentials/physiology , Excitation Contraction Coupling/physiology , Muscle Contraction/physiology , Muscle, Skeletal/physiology , Myasthenia Gravis/diagnosis , Myasthenia Gravis/physiopathology , Accelerometry/methods , Adult , Aged , Female , Hand Strength/physiology , Humans , Male , Middle Aged , Refractory Period, Electrophysiological/physiology , Young Adult
18.
PLoS One ; 10(5): e0126579, 2015.
Article in English | MEDLINE | ID: mdl-25965387

ABSTRACT

PURPOSE: To investigate the association between glucocorticoid-induced osteoporosis and myasthenia gravis (MG) using a cross-sectional survey in Japan. METHODS: We studied 363 patients with MG (female 68%; mean age, 57 ± 16 years) who were followed at six Japanese centers between April and July 2012. We evaluated the clinical information of MG and fractures, bone markers, and radiological assessment. Quality of life was measured using an MG-specific battery, MG-QOL15. RESULTS: Glucocorticoids were administered in 283 (78%) of 363 MG patients. Eighteen (6%) of 283 MG patients treated with prednisolone had a history of osteoporotic fractures. The duration of glucocorticoid therapy, but not the dose of prednisolone, was associated with the osteoporotic fractures in MG patients. Bone mineral density was significantly decreased in the MG patients with fractures. The multivariate analyses showed that the total quantitative MG score was the only independent factor associated with osteoporotic fractures (OR = 1.30, 95% CI 1.02-1.67, p = 0.03). MG patients who had experienced fractures reported more severe difficulties in activities of daily living. CONCLUSION: Glucocorticoid-induced osteoporosis aggravates quality of life in patients with MG.


Subject(s)
Fractures, Bone/physiopathology , Glucocorticoids/adverse effects , Myasthenia Gravis/physiopathology , Osteoporosis/physiopathology , Adult , Aged , Bone Density , Female , Fractures, Bone/chemically induced , Fractures, Bone/epidemiology , Humans , Male , Middle Aged , Myasthenia Gravis/chemically induced , Myasthenia Gravis/epidemiology , Osteoporosis/chemically induced , Osteoporosis/epidemiology , Quality of Life
19.
Tohoku J Exp Med ; 235(4): 305-10, 2015 04.
Article in English | MEDLINE | ID: mdl-25843429

ABSTRACT

Very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency is characterized by impaired mitochondrial ß-oxidation of fatty acids. The fatty acid oxidation plays a significant role in energy production especially in skeletal muscle. VLCAD is one of four acyl-CoA dehydrogenases with different-chain length specificity and catalyzes the initial step in mitochondrial ß-oxidation of fatty acids. While the clinical phenotypes in neonates and infants are described as severe, adolescent-onset or adult-onset VLCAD deficiency has a more benign course with only skeletal muscle involvement. These myopathic phenotypes are characterized by episodic muscle weakness and rhabdomyolysis triggered by fasting and strenuous exercise. We report a male teenager who manifested repeated episodes of rhabdomyolysis immediately after exertional exercise. Rhabdomyolysis was diagnosed based on the marked elevation of serum creatine kinase and myoglobinuria. Acylcarnitine analysis by tandem mass spectrometry (MS/MS) revealed elevation of serum tetradecenoylcarnitine (C14:1-AC), which represents an abnormal acylcarnitine profile associated with the mitochondrial ß-oxidation defect. High performance liquid chromatographic analysis showed decreased production of 2-hexadecenoyl-CoA (C16:1) from palmitoyl-CoA (C16:0), indicating the defect of VLCAD activity. Direct sequencing of the acyl-CoA dehydrogenase, very long-chain gene (ACADVL) that codes VLCAD revealed a heterozygous mutation (c.1242G>C) in exon 12 (E414D), which is a novel mutation in myopathic-type VLCAD deficiency. Because VLCAD functions as a homodimer, we assume that this heterozygous mutation may exhibit dominant-negative effect. This patient remains asymptomatic thereafter by avoiding exertional exercise. The findings of reduction of enzyme activity and clinical features associated with this novel missense mutation of VLCAD are discussed.


Subject(s)
Acyl-CoA Dehydrogenase, Long-Chain/deficiency , Exercise , Lipid Metabolism, Inborn Errors/complications , Lipid Metabolism, Inborn Errors/genetics , Mitochondrial Diseases/complications , Mitochondrial Diseases/genetics , Muscular Diseases/complications , Muscular Diseases/genetics , Mutation, Missense/genetics , Rhabdomyolysis/complications , Rhabdomyolysis/etiology , Acyl-CoA Dehydrogenase, Long-Chain/blood , Acyl-CoA Dehydrogenase, Long-Chain/chemistry , Acyl-CoA Dehydrogenase, Long-Chain/genetics , Adolescent , Amino Acid Sequence , Base Sequence , Carnitine/analogs & derivatives , Carnitine/blood , Congenital Bone Marrow Failure Syndromes , Heterozygote , Humans , Infant, Newborn , Lipid Metabolism, Inborn Errors/blood , Lipid Metabolism, Inborn Errors/enzymology , Male , Mitochondrial Diseases/blood , Mitochondrial Diseases/enzymology , Models, Molecular , Molecular Sequence Data , Muscular Diseases/blood , Muscular Diseases/enzymology , Protein Structure, Tertiary , Sequence Alignment
20.
Muscle Nerve ; 51(5): 692-6, 2015 May.
Article in English | MEDLINE | ID: mdl-25155615

ABSTRACT

INTRODUCTION: The aim of this study was to elucidate the effectiveness of oral prednisolone (PSL) according to dosing regimen in 472 patients with myasthenia gravis (MG). METHODS: We compared the clinical characteristics and PSL treatment between 226 patients who achieved minimal manifestations (MM) or better and 246 patients who remained improved (I) or worsened, according to the MG Foundation of America postintervention status. RESULTS: Achievement of MM or better at peak PSL dose (odds ratio 12.25, P < 0.0001) and combined use of plasma exchange/plasmapheresis (PE/PP) and/or intravenous immunoglobulin (IVIg) (odds ratio 1.92, P = 0.04) were associated positively, and total PSL dose during the past year (odds ratio 0.17, P = 0.03) was associated negatively with present MM or better status. CONCLUSIONS: Higher PSL dose and longer PSL treatment do not ensure better outcome. In the absence of a good response, the PSL dose should be decreased by combining with modalities such as PE/PP or IVIg.


Subject(s)
Adrenal Cortex Hormones/administration & dosage , Adrenal Cortex Hormones/therapeutic use , Myasthenia Gravis/drug therapy , Prednisolone/administration & dosage , Prednisolone/therapeutic use , Severity of Illness Index , Administration, Oral , Adolescent , Adult , Aged , Aged, 80 and over , Combined Modality Therapy , Cross-Sectional Studies , Dose-Response Relationship, Drug , Female , Humans , Immunoglobulins, Intravenous/therapeutic use , Japan , Longitudinal Studies , Male , Middle Aged , Myasthenia Gravis/diagnosis , Plasma Exchange , Regression Analysis , Treatment Outcome , Young Adult
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