Clinical, pathological and genetic studies of two cases of childhood-onset nemaline myopathy / 中国当代儿科杂志

This article reports two cases of childhood-onset nemaline myopathy diagnosed by muscle pathology and genetic diagnosis. The two patients had onset in early childhood, with muscle weakness as the first manifestation, as well as long disease duration and slow progression. Gomori staining and hematoxylin-eosin staining showed red-stained rods in the sarcoplasmic cytoplasm and sarcolemma under a light microscope. Electron microscopy showed that the dense nemaline rods were located under the muscle fiber sarcolemma and parallel to the long axis of the muscle fibers, and some muscle fiber myofilaments were dissolved and necrotic. Gene testing found that one of the two patients had heterozygous mutation (c.1013A>C) in the ACTA1 gene, and the other had compound heterozygous mutation (c.18676C>T and c.9812C>A) in the NEB gene. The two mutations were more common in nemaline myopathy. Nemaline myopathy is a recessive or dominant inheritance myopathy, in which the nemaline rod in the cytoplasm of myocytes is a characteristic muscle pathological change. Pathological and genetic diagnosis is the gold standard for diagnosis of nemaline myopathy.

Clinical and pathological features of 50 children with Duchenne's muscular dystrophy / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the clinical and pathological features of children with Duchenne muscular dystrophy (DMD), with the aim of increasing the possibility of early diagnosis.</p><p><b>METHODS</b>The clinical data of 50 children who were definitely diagnosed with DMD, based on clinical manifestations and the results of skeletal muscle biopsies and monoclonal antibody immunohistochemical staining, was reviewed.</p><p><b>RESULTS</b>The children showed similar clinical manifestations, including running slowly in the toddler period, muscle weakness when climbing stairs and standing up followed by squatting down and walking abnormalities a predominant increase in serum creatine kinase level increased dominantly, and myopathic lesions seen on electromyography. Hematoxylin-eosin staining showed similar pathological presentations in all 50 children, including different-sized muscle fibers with rounding, degeneration and necrosis in various degrees, and proliferation of connective tissues. There was some inflammatory cell infiltration in muscle fibers and interstitial tissues. Dystrophin expression was completely absent at the sarcolemma in all 50 children, and sarcoglycan-α,-β, -',-δ expression was reduced to various degrees in 33 of them.</p><p><b>CONCLUSIONS</b>For children with the clinical manifestations mentioned above, skeletal muscle biopsies and monoclonal antibody immunohistochemical staining are recommended as these examinations contribute to a definite diagnosis of DMD by demonstrating dystrophin deficiency at the sarcolemma.</p>

Congenital myopathy with type 1 fiber predominance in two children / 中国当代儿科杂志

Non-progressive congenital myopathy is a group of muscle diseases occurring at birth or during teenage years. A number of new reports of congenital myopathy, such as homogeneous bodies myopathy, muscle quality control myopathy and type 1 fiber predominance have recently been reported, but they lack of sufficient quantity and constant clinico-pathologic manifestations. This paper reports two cases of congenital myopathy with type 1 fiber predominance confirmed by muscle biopsy. The clinical manifestations of the two children (a 4.5-year-old girl and an 11-year-old boy) included non-progressive symptoms of muscle weakness, skeletal deformities and other clinical features of congenital myopathy. The physical examinations showed a long face or figure and funnel chest or kyphosis/scoliosis, high palatal arch and wing-like shoulder. Serum levels of creatine kinase were normal but slightly elevated serum lactate dehydrogenase levels were noted in the two children. The skeletal muscle biopsy by ATPase staining showed that type 1 fibers accounted for more than 90% of the total number of muscle fibers. No other abnormal pathological changes, such as central cores, muscle tube and central nuclei, were found in the two children.

Changes of expression of FADD and Daxx following focal cerebral ischemia in rats / 中华神经科杂志

Objective To investigate the changes of expression of Fas-associated proteins named Fas-associated death domain protein(FADD)and death-associated protein(Daxx)in the ischemic penumbra following transient focal cerebra ischemia in rats.Methods ①Adult male Sprague-Dawley rats were randomly divided into the sham-operated group and the cerebral ischemia model group.Rats underwent right middle cerebral artery occlusion(MCAO)for 2 h and reperfusion for 1,3,6,12 and 24 h using an intraluminal suture technique.The expression of FADD and Daxx mRNA and protein were measured with methods of immunohistochemistry.Western blot and reverse transcription-polymerase chain reaction(RT- PCR)respectively were used in the ischemic penumbra of rats.②Double-label fluorescence confocal laser scanning microscopy(CLSM)was performed to monitor FADD and Daxx intracellular location before and after ischemia.Results RT-PCR,Immunohistochemistry,Western blot experiments indicated that a very low level of FADD mRNA and protein were detected in the cerebral cortex of sham rats.The expression level both of FADD mRNA and protein increased significantly at 3 h after reperfusion,peaked at 12 h,then declined markedly at 24 h in the ischemic penumbra of model rats.RT-PCR,Immunohistochemistry indicated that a relatively high level of Daxx mRNA was detected in the cerebral cotex of sham rats.The expression level of Daxx mRNA increased significantly at 3 h after reperfusion and persisted to 24 h at a high level,whose protein had a same change of expression level in the ischemic penumbra of model rats. Immunofluorescence double-staining laser scanning by CLSM showed that the immunoreactivity of FADD was located in cytoplasm,and the intracellular translocation of the immunoreactivity of Daxx from nucleus to cytoplasm was monitored by measuring the green fluorescence after ischemia.Conclusion The transient upregulation of FADD and the persistant high level of expression of Daxx may contribute to neuronal apoptosis following cerebral ischemia/reperfusion.