Journal of the neurological sciences
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A boy, who had shown muscle weakness and hypotonia from early childhood and fiber type disproportion (FTD) with no dystrophic changes on muscle biopsy, was initially diagnosed as having congenital fiber type disproportion (CFTD). Subsequently, he developed cardiac conduction blocks. We reconsidered the diagnosis as possible LMNA-myopathy and found a heterozygous mutation in the LMNA gene. ⋯ Four of 23 muscular dystrophy patients with LMNA mutation also showed fiber type disproportion (FTD). Importantly, all FTD associated with LMNA-myopathy were caused by hypertrophy of type 2 fibers as compared with age-matched controls, whereas CFTD with mutations in ACTA1 or TPM3 showed selective type 1 fiber atrophy but no type 2 fiber hypertrophy. Although FTD is not a constant pathological feature of LMNA-myopathy, we should consider the possibility of LMNA-myopathy whenever a diagnosis of CFTD is made and take steps to prevent cardiac insufficiency.
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Inflammation causes upregulation of NaV1.7 sodium channels in the associated dorsal root ganglia (DRG). The resultant increase in sodium influx must be countered to maintain osmotic homeostasis. The primary mechanism to pump sodium out of neurons is Na(+), K(+)-ATPase. ⋯ Paw stimulation doubled this difference. Control DRG showed little neuronal death. These results are evidence that regulation of Na(+), K(+)-ATPase during major inflammatory disease states is critical for homeostatic protection of primary afferent neurons.
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Glycogen synthase kinase-3β (GSK-3β) activity plays a central role in motor neuron degeneration. GSK-3β inhibitors have been shown to prolong motor neuron survival and suppress disease progression in amyotrophic lateral sclerosis (ALS). In this study, we evaluated the therapeutic effects of a new GSK-3b inhibitor, JGK-263, on ALS in G93A SOD1 transgenic mice. ⋯ These results suggest that JGK-263, an oral GSK-3β inhibitor, is promising as a novel therapeutic agent for ALS. Still, further biochemical studies on the underlying mechanisms and safety of JGK-263 are necessary.