title: Myosin heavy chain composition in human masticatory muscles by immunohistochemistry and gel electrophoresis.
abstract: In this study we compared the immunohistochemically quantified fiber type area with the myosin heavy chain (MyHC) contents of a bundle of fibers from a human masticatory muscle. The total cross-sectional areas were determined immunohistochemically for the three major fiber types (I, IIA, and IIX) in bundles of fibers (n=42) taken from the anterior and posterior belly of the human digastric muscle (n=7). The relative MyHC contents of the same fiber bundles were determined electrophoretically (MyHC-I, -IIA, and -IIX; anterior, 32%, 35%, and 33%; posterior, 39%, 42%, and 19%) and compared with the immunohistochemical data (MyHC-I, -IIA, and -IIX; anterior, 32%, 31%, and 37%; posterior, 39%, 45%, and 15%). No significant differences were seen in the mean fiber type distribution between the two techniques; the correlation coefficient ranged from 0.71 to 0.96. The correlation coefficient was higher for MyHC type I and MyHC type IIX than for MyHC type IIA. The MyHC contents of single fibers taken from the posterior belly indicated that many fibers in this belly co-express MyHC-IIA and MyHC-IIX. Despite the presence of these hybrid fibers, the correspondence between both methods was relatively large.
authors.affiliation: Department of Functional Anatomy, Academic Centre for Dentistry Amsterdam, Amsterdam, The Netherlands. j.a.korfage@amc.uva.nl
authors.forename: J A M
authors.initials: JA
authors.lastname: Korfage
authors.forename: T M G J
authors.initials: TM
authors.lastname: Van Eijden
mesh_terms: D000368:Aged; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008410:Masticatory Muscles / Q000737:chemistry*; D018995:Myosin Heavy Chains / Q000737:chemistry*
chemical_list: D018995:Myosin Heavy Chains