title: Pax7-Positive Cells/Satellite Cells in Human Extraocular Muscles.
abstract: OBJECTIVE
  We quantified and investigated the distribution of Pax7-positive cells/satellite cells (SCs) in the human extraocular muscles (EOMs).
  
  
  METHODS
  An immunofluorescence multiple-marker method simultaneously combining two SC markers (Pax7, NCAM), detection of the basement membrane (laminin) and cell nuclei (4',6-diamidino-2-phenylindole [DAPI]), was used on the anterior, middle, and posterior portions of EOMs from five healthy donors. Pax7-positive cell and SC content, myonuclear content, myofiber cross-sectional area, and myonuclear domain were analyzed in single cross-sections. Between 3915 and 13,536 myofibers per muscle cross-section and myofibers from the entire EOM cross-section were analyzed for quantification of Pax7-positive cells per myofiber (Pax7/F).
  
  
  RESULTS
  The number of Pax7/F in the human EOMs varies along the length of the muscle with twice as high Pax7/F in the anterior part of the EOMs, but within the range of what has been previously reported for normal adult limb muscles. Furthermore, there are Pax7-positive cells in positions other than the classical SC position and the myonuclear domain size of adult EOMs is noticeably smaller than that previously reported for other adult skeletal muscles.
  
  
  CONCLUSIONS
  Previous data on differences in Pax7-positive cell/SC abundance between EOMs and limb muscles must be reconsidered and the characteristics of different Pax7-positive cell populations further investigated. Higher numbers of Pax7-positive cells in the anterior portion of the EOMs may have a bearing for strabismus surgery involving sectioning of the muscle fibers.
authors.affiliation: Department of Integrative Medical Biology, Umeå University, Umeå, Sweden.
authors.forename: Mona
authors.initials: M
authors.lastname: Lindström
authors.affiliation: Department of Integrative Medical Biology, Umeå University, Umeå, Sweden 2Department of Clinical Sciences, Ophthalmology, Umeå University, Umeå, Sweden.
authors.forename: Anton E
authors.initials: AE
authors.lastname: Tjust
authors.affiliation: Department of Integrative Medical Biology, Umeå University, Umeå, Sweden 2Department of Clinical Sciences, Ophthalmology, Umeå University, Umeå, Sweden.
authors.forename: Fatima
authors.initials: F
authors.lastname: Pedrosa Domellöf
mesh_terms: D000328:Adult; D000368:Aged; D001485:Basement Membrane; D002467:Cell Nucleus; D002478:Cells, Cultured; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D032446:Myoblasts / Q000166:cytology / Q000378:metabolism; D009801:Oculomotor Muscles / Q000166:cytology / Q000378:metabolism*; D051763:PAX7 Transcription Factor / Q000378:metabolism*
chemical_list: D051763:PAX7 Transcription Factor; C497321:PAX7 protein, human