Acquired @entity73 : a form of XXXX with prolonged open time of the @entity934 receptor channel.

@entity1 @entity19 @entity73 @entity4836 @entity1737 @entity934
A 32-year-old female presented with a 2-year history of fluctuating generalized weakness including extraocular, bulbar, and limb muscles, suggesting @entity1737 , but with poor response to @entity4836 and unusual electromyographic findings. After rest, power increased on repeated maximal contractions, followed by progressive weakness. There were decremental responses at low-frequency stimulation, but incremental responses at high frequencies, and single stimuli evoked repetitive compound muscle action potentials. Plasmapheresis was ineffective. In a conventional assay, antibodies against @entity934 receptors (AChRs) were borderline. However, in an assay using cells expressing mainly adult-type @entity1 AChRs, the patient's serum was positive. Thymectomy revealed a hyperplastic thymus. An intercostal muscle specimen revealed small miniature end-plate potentials, 0.22+/-0.02 mV instead of 0.56+/-0.05 mV in controls. The number of 125I-alpha-bungarotoxin binding sites was normal. The decay time constant of end-plate potentials was increased from 5.3+/-0.6 msec in controls to 23+/-3.6 msec in the @entity1 . Ultrastructurally, there was no destruction of the end plate. Transfer of the @entity1 's plasma to @entity19 in vivo produced similar physiological changes in their diaphragms. We conclude that the @entity1 has an immune-mediated disorder, in which an antibody specific to the adult form of the AChRs alters the channel properties, reducing total current and slowing the closure. We propose the name "acquired @entity73 " for this variant of @entity1737 .
