title: Myosin heavy chain composition and fiber size of the cricopharyngeus muscle in patients with achalasia and normal subjects.
abstract: OBJECTIVE
  Cricopharyngeal achalasia (CA) can be defined as inadequate opening of the cricopharyngeus muscle (CPM) resulting in dysphagia. Myosin heavy chain (MHC) isoform fiber type composition and size are key determinants of muscle function. These parameters have not been described in CA. It is hypothesized that there is a difference between the MHC isoform composition of the CPM in patients with the clinical diagnosis of CA and that in normal subjects.
  
  
  METHODS
  Patients who had received prior botulinum were excluded. The MHC fiber type composition and size in patients and cadaveric controls were determined by adenosine triphosphatase staining and image analysis.
  
  
  RESULTS
  The CPMs of 12 CA patients (6 male, 6 female; mean age, 61 years) and 5 control cadaveric subjects (3 male, 2 female; mean age, 67 years) were analyzed. There were relatively fewer type I fibers (67%) in patients with CA than in controls (81%), but the difference was not significant (p = .18). Type I fibers were slightly smaller in CA patients (38.7 microm) than in controls (47.2 microm), but this was not significantly different (p > .05). Of the 12 CA patients, 3 had type II predominance, a feature not seen in normal subjects.
  
  
  CONCLUSIONS
  Patients with CA had relatively fewer type I fibers, although the difference was not statistically significant. The MHC isoform composition and fiber size were not different between CA patients and normal subjects. This is the first report to characterize the CPM in patients with CA.
authors.affiliation: Division of Laryngology and Professional Voice, Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, USA.
authors.forename: Melinda V
authors.initials: MV
authors.lastname: Davis
authors.forename: Albert L
authors.initials: AL
authors.lastname: Merati
authors.forename: Safwan S
authors.initials: SS
authors.lastname: Jaradeh
authors.forename: Joel H
authors.initials: JH
authors.lastname: Blumin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D004931:Esophageal Achalasia / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D049631:Esophageal Sphincter, Upper / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology; D018485:Muscle Fibers, Skeletal / Q000378:metabolism / Q000473:pathology*; D018995:Myosin Heavy Chains / Q000378:metabolism*; D012189:Retrospective Studies
chemical_list: D018995:Myosin Heavy Chains