0000000000376984
AUTHOR
Kenneth Ricker
Two cases of adynamia episodica hereditaria: In vitro investigation of muscle cell membrane and contraction parameters
Membrane potentials, current-voltage relationships, and contractile parameters were studied in intact muscle cell bundles obtained from two patients with adynamia episodica hereditaria. In a normal extracellular medium, the cell membranes had resting potentials of about -80 mV and their current-voltage relationships were not significantly different from control curves. In contrast to normal muscles the afflicted cells were paralyzed in a medium having 6-10 mmol/liter potassium. The mechanisms of paralysis in the two specimens were different from each other. Many fibers from one patient were spontaneously active even in normal solution. In high potassium solution spontaneous activity was inc…
Muscle pathology in 57 patients with myotonic dystrophy type 2
We evaluated muscle biopsies from 57 patients with genetically confirmed myotonic dystrophy type 2/proximal myotonic myopathy (DM2/PROMM). Light microscopy showed myopathic together with “denervation-like” changes in almost all biopsies obtained from four different muscles: increased fiber size variation, internal nuclei, small angulated fibers, pyknotic nuclear clumps, and predominant type 2 fiber atrophy. Quantitative morphometry in 18 biopsies that were immunostained for myosin heavy chain confirmed a predominance of nonselective type 2 fiber atrophy. These histological changes were similar in all patients regardless of the site of biopsy, the predominant clinical symptoms and signs, and…
Immunosuppressive treatment of rippling muscles in patients with myasthenia gravis
Rippling muscle disease is a rare autosomal dominant disorder that may occur sporadically. In this report two patients presenting with rippling muscles followed by myasthenia gravis are described. Our first patient developed rippling muscles about 1 month after infection with Yersinia enterocolitica. Two years later myasthenia gravis appeared. Our second patient had a 2-year history of asthma prior to the onset of rippling muscles which preceded the myasthenic symptoms by 4-8 weeks. Acetylcholine receptor and anti-skeletal muscle antibody titers were positive in both patients. In both patients the rippling phenomena worsened with pyridostigmine treatment but markedly improved after immunosu…