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A 14-year-old male pediatric patient was admitted to the hospital mainly because of neck and back deformity, with limited activity for 7 yr, dysphagia and short of breath for more than 10 months.He was diagnosed with cervical lordosis deformity, RyR1 gene-related myopathy, high possibility of multi-minicore disease and being susceptible to malignant hyperthermia.Posterior cervical orthopedic internal fixation surgery was successfully performed under total intravenous anesthesia with propofol.The vital signs were stable during anesthesia and operation which lasted for 10 h. The patient was admitted to intensive care unit after the uneventful operation.When emerging from general anesthesia, the patient suddenly presented with symptoms of muscular fasciculation in the head, face, trunk and limbs, along with elevated body temperature as high as 39.4℃, severe acidosis and hypercapnia, meanwhile, the blood creatine kinase, blood myoglobin and urinary myoglobin gradually increased.The patient was diagnosed with malignant hyperthermia based on the clinical grading scale score of 63.Dantrolene sodium was infused intravenously, combined with multiple treatments such as physical cooling, correction of acidosis and electrolyte disturbance, alkalization of urine, intermittent hemofiltration and plasma exchange.The arrhythmia and delirium were treated symptomatically.The pediatric patient was fully recovered and discharged with good outcomes.
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Objective: To explore sarcoplasmic reticulum ryanodine receptor2 (RyR 2) expression and calcium releasing function in chronic heart failure (CHF) rabbits and to study the impact of long term valsartan treatment in relevant animals. Methods: HF model was established by volume overloading with pressure overloading in experimental rabbits. 27 rabbits were divided into 3 groups: Sham group, HF group and HF+valsartan group. n=9 in each group and the animals were treated for 7 weeks. Left ventricular structure, hemodynamic parameters, expression and functional changes of myocardiocyte sarcoplasmic reticulum RyR 2 were observed and compared among different groups. Results: Compared with Sham group, HF group had increased left ventricular mess index (LVMI), left ventricular end diastolic pressure (LVEDP) and decreased left ventricular shortening fraction, LVEF, all P<0.05. Compared with HF group, HF+valsartan group showed decreased LVMI, LVEDP and increased left ventricular shortening fraction, LVEF, all P<0.05. Sarcoplasmic reticulum RyR 2 expression and calcium releasing function were lower in HF group than Sham group, P<0.05; while they were both higher in HF+valsartan group than HF group, P<0.05. Conclusion: Long term application of valsartan could improve the cardiac function which might be related to increased myocardial sarcoplasmic reticulum RyR 2 expression and calcium releasing function in experimental CHF rabbits.
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Calcium/calmodulin-dependent protein kinaseⅡ (CaMKⅡ) has multiple functions, which made it play a central role in cardiovascular disease. Especially it activates numerous downstream targets in various signaling pathways that promotes vascular disease, heart failure, myocardial hypertrophy and arrhythmias. CaMKⅡcan impact calcium balance and increase calcium leak in myocardial cell via phosphorylating L type calcium channel, Ryanodine receptor (RyR 2) and phos?pholamban (PLN), and regulate ATP sensitive potassium current (IKATP) and late sodium current by affecting sodium channels and potassium channels. In addition, It can directly regulate transcription via activating the silk crack the original activated protein kinases (MAPKs) and acetylation enzyme (HDAC). These mechanisms have important roles in myocardial hypertro?phy, heart failure and arrhythmia. So we focus to demonstrating the structure and action mechanism of CaMKⅡto improve a new therapy of cardiovascular disease.
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Introdução: A miopatia centronuclear é uma doença muscular congênita com apresentação clínica heterogênea, caracterizada histologicamente pela proeminência de fibras musculares com núcleos centralizados. Três formas são reconhecidas: neonatal grave, com herança ligada ao X e envolvimento do gene MTM1; autossômica dominante, com início geralmente tardio e curso mais leve, associada a mutações no gene DNM2; e autossômica recessiva, com gravidade intermediária entre as outras formas e envolvimento dos genes BIN1, RYR1 ou TTN. Apesar da identificação dos principais genes responsáveis pela doença, os métodos usuais de diagnóstico genético não encontram mutações em cerca da metade dos casos. Objetivo: O objetivo deste estudo foi a caracterização clínica, histológica e molecular de pacientes brasileiros portadores de miopatia centronuclear. Métodos: Laudos de dois bancos de biópsia muscular foram usados para identificar pacientes com diagnóstico de miopatia centronuclear nos últimos dez anos. As lâminas das biópsias foram revisadas e analisadas, e as famílias correspondentes convocadas para aplicação de protocolo clínico e coleta de sangue periférico para extração de DNA genômico. As famílias foram estudadas para os genes conhecidos por sequenciamento Sanger, MLPA, painel de genes implicados em doenças neuromusculares ou sequenciamento de exoma. Resultados: Foram convocados 24 pacientes provenientes de 21 famílias, em 16 das quais foi possível estabelecer o diagnóstico molecular. As 7 famílias com a forma neonatal grave constituíam um grupo homogêneo clínica e histologicamente, e mutações novas e conhecidas foram encontradas no gene MTM1 em 6 destas. Dois meninos deste grupo, com evolução estável, tiveram óbito súbito por choque hipovolêmico subsequente a rompimento de cisto hepático. O gene MTM1 também foi implicado em uma menina portadora manifestante, com quadro mais leve, na forma de uma macrodeleção em heterozigose, detectada por MPLA...
Introduction: Centronuclear myopathy is a heterogeneous congenital muscle disease, characterized by the prominence of centralized nuclei in muscle fibers. Three disease forms are recognized: a severe neonatal, X-linked form caused by mutations in the MTM1 gene; an autosomal dominant, late-onset milder form, associated to the DNM2 gene; and an autosomal recessive form, with intermediate severity, so far with the BIN1, RYR1 or TTN genes implicated. In spite of the identification of these genes, usual molecular diagnostic methods don't yield a molecular diagnosis in about half of cases. Objetives: The aim of this work was to study clinical, histological, and molecular aspects of centronuclear myopathy Brazilian patients. Methods: Reports taken from two muscle biopsy banks were used to identify centronuclear myopathy patients in the last ten years. Biopsy slides were reviewed and analyzed, and corresponding families recruited to apply a clinical protocol and to draw peripheral blood to extract genomic DNA. Families were studied for known genes via Sanger sequencing, MLPA, panel of genes implicated in neuromuscular diseases, or exome sequencing. Results: Twentyfour patients out of 21 families were recruited, and in 16 families molecular diagnosis was established. The 7 families with the severe neonatal form amounted to a clinically and histologically homogeneous group, and mutations, both known and novel, were found in the MTM1 gene in 6 of these. Two boys of this group, with a stable course, died suddenly of hypovolemic shock due to a hepatic cyst rupture. The MTM1 gene was also implicated in the case of a mild manifesting carrier girl with a heterozygous macrodeletion detected via MLPA...
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Humans , Male , Female , Infant , Child, Preschool , Child , Adolescent , Young Adult , Middle Aged , Biopsy , Dynamin II , Exome , High-Throughput Nucleotide Sequencing , Muscle Hypotonia , Myopathies, Structural, Congenital , Ryanodine Receptor Calcium Release ChannelABSTRACT
Objective To investigate the effects of trimebutine maleate (TM) on the expression of large conductance calcium-activated potassium channel (BKCa) and ryanodine receptors (RyR)channels at mRNA and protein level in colonic smooth muscle cell of cold restraint stress(CRS)induced rats.Methods A total of 24 Wistar rats were divided into CRS group,CRS with TM group and control group equally.The rats of CRS group were gavaged with 0.9％NaCl (6 ml/kg) daily; the rats of CRS with TM group were gavaged with 15 g/L TM (6 ml/kg) daily and activity was restricted in wire cage at 4 ℃ for two hours,continuously for five days.The rats of control group were gavaged with 0.9 ％ NaCl (6 ml/kg) once without CRS.The amount and characteristics of stool of rats in each group were observed.The colonic smooth muscle was isolated to detect the expression of BKCa and RyR at mRNA and protein level by reverse transcription-polymerase chain reaction (RT-PCR) and Western Blot.Results The median of rats defecation particles of CRS group was six,control group was one and CRS with TM group was five.Compared with control group,the defecation appearance of CRS group and CRS with TM group was looser and wetter observed by naked eyes.Compared with control group,there was no obvious pathological changes in CRS and CRS with TM group.There was no significant difference in the mRNA expression of BKCa and RyR channels between control group and CRS group.Compared with control group,the BKCa expression at mRNA level of CRS with TM group increased 1.45 fold.Compared with control group,the RyR2 expression at mRNA level of CRS with TM group increased 1.32 fold.Compared with control group,the BKCa expression at protein level of CRS with TM group increased 1.39 fold,and there was no RyR2 expression band at protein level.Conclusion TM might affect colonic smooth muscle contraction through the upregulation of BKCa expression at mRNA and protein level and RyR expression at mRNA level.
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Objective To screen the ryanodine receptor type 1(RYR1)gene in a Chinese pedigree with malignant hyperthermia(MH).Methods Total genome was extracted conventionally from peripheral leucocytes of the prohand and the other members of the family.In order to detect mutations in the RYR1 gene,part exons were amplified by polymerase chain reaction(PCR)and then subjected tO automatic DNA sequencing.The detected mumfion in the gene was confirmed in the preband and the other members of the family using Fok Ⅰ restriction analysis.Results DNA sequencing of PCR-amplified fragments of the pwband revealed c.6724C＞T (P.T2206M),a recurrent missense mutation which had been detected in Caucasian MH cages.Restriction analysis of all available family members showed that one daughter and one son of the 4 children of the proband were the missense mutation carriers,indicating that they were MH-susceptible individuals.Conclusion The Chinese susceptible to MH carries the simile RYR1 gene mutation to the Caucasians susceptible to MH.
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To investigate the mechanism by which the C-terminus (4,938-5,037) of the ryanodine receptor 1 (RyR1) homo-tetramerizes, forming a functional Ca2+ -release channel, the structural requirements for the tetramerization were studied using site-directed mutagenesis. Alanine-substitutions at five charged residues, E4976, H5003, D5026, E5033 and D5034, significantly decreased the formation of homo-dimers (reduced by > 50%). Interaction between the C-terminus and cytoplasmic loop I (4,821-4,835) required two positively charged residues, H4832 and K4835. Based on the predicted protein secondary structures, all seven charged residues are located in random coils. Paired alanine-substitutions at six negatively charged residues (E4942A/D4953A, D4945A/E4952A and E4948A/ E4955A) of the alpha-helix (4,940-4,956) in the C-terminus increased homo-dimerization. Therefore, the homo-tetramerization of RyR1 may be mediated by intra- and/or inter-monomer electrostatic interactions among the C-terminal charged residues in random coils or in an alpha-helix.
Subject(s)
Animals , Rabbits , Amino Acid Sequence , Dimerization , Models, Molecular , Molecular Sequence Data , Mutagenesis, Site-Directed , Protein Structure, Quaternary , Protein Structure, Secondary , Recombinant Fusion Proteins/chemistry , Ryanodine Receptor Calcium Release Channel/chemistry , Sequence Homology, Amino Acid , Static ElectricityABSTRACT
Objective To investigate the clinical significance of myasthenia gravis (MG) associated autoantibodies.Methods Titin,ryanodine receptor (RyR)and acetylcholine receptor (AChR) antibodies were examined in the sera of 74 myasthenia gravies patients by ELISA.Results AChR,Titin, RyR antibodies were detected in 77.0% (57/74),39.2% (29/74) and 32.4% (24/74) of the MG patients,respectively.For thymoma MG,AChR,Titin and RyR antibodies were detected in 76.2% (16/21),71.4% (15/21) and 52.4% (11/21) respectively.For late onset MG,Titin and RyR antibodies were detected in 77.3% (17/22) and 50.0% (11/22) respectively.With respect to the modified Osserman classification,the positve rate for Titin and RyR antibodies is much higher in more severe patients (X~2= 16.094,P=0.001;X~2=11.226,P=0.011).Titin antibodies was significantly related with RyR antibodies (r=0.380,P=0.001).Conclusions Titin and RyR antibodies show high sensitivity for thymoma MG,and the combination of serological and radiological testing can increase both sensitivity and specificity in diagnosis of thymoma MG.The levels of the two antibodies may serve as important prognosis markers in MG.The induction of the immune response against Titin and RyR and the possible pathogenic effects of the two antibodies will be further studied.
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Objective To evaluate the significance to detect the Ryanodine receptor (RyR) antibody in the sera of myasthenia gravis (MG) patients.Methods Sarcoplasmic reticulum abound with RyR was extracted by centrifugation,and levels of antibodies in 66 MG patients with thymoma (MGT),98 non-thymoma MG (NTMG) patients,50 non-myasthenia gravis (NMG) patients and 123 normal persons were examined by ELISA-RyR method.Results RyR antibody positive rate of MGT was the highest among MGT,NTMG and NMG groups ( P 0.05).Ages,clinical scores and levels of acetycholine receptor antibodies of patients with RyR antibody positive sera were higher than those with RyR antibody negative sera ( P