title: Structural changes in male trapezius muscle with work-related myalgia.
abstract: Muscular changes in male forest machine operators with work-related neck and shoulder myalgia were studied. Enzyme cyto- and immunohistochemical analysis was carried on muscle biopsies obtained from ten myalgic subjects (M), nine non-myalgic selected in the same work place (NM) and six healthy young men (C). The M group displayed a significant increase in type IIA fibres in comparison to the C group. This hypertrophy was accompanied by a parallel increase in the capillary bed. Both the M and NM groups exhibited an increase in fibres with a disorganised mitochondrial pattern. Interestingly, fibres lacking cytochrome c oxidase occurred in the M group (0.9%) but also in the NM group (0.5%), suggesting a mitochondrial defect. Central nuclei (5.2%) and developmental myosin (3%) were also more frequent in the M group. These changes are probably related to injury-regeneration cycles. These data support the association between the work conditions and muscle changes in work-related trapezius myalgia.
authors.affiliation: Department of Anatomy, Umeå University, Sweden.
authors.forename: F
authors.initials: F
authors.lastname: Kadi
authors.forename: G
authors.initials: G
authors.lastname: Hägg
authors.forename: R
authors.initials: R
authors.lastname: Håkansson
authors.forename: S
authors.initials: S
authors.lastname: Holmner
authors.forename: G S
authors.initials: GS
authors.lastname: Butler-Browne
authors.forename: L E
authors.initials: LE
authors.lastname: Thornell
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000328:Adult; D002196:Capillaries / Q000502:physiology; D003576:Electron Transport Complex IV / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D018656:Muscle Fibers, Fast-Twitch / Q000201:enzymology / Q000648:ultrastructure; D018485:Muscle Fibers, Skeletal / Q000648:ultrastructure; D018657:Muscle Fibers, Slow-Twitch / Q000201:enzymology / Q000648:ultrastructure; D018482:Muscle, Skeletal / Q000098:blood supply / Q000473:pathology* / Q000648:ultrastructure; D009135:Muscular Diseases / Q000201:enzymology / Q000473:pathology*; D009243:NAD / Q000378:metabolism; D009784:Occupational Diseases / Q000201:enzymology / Q000473:pathology*; D010146:Pain / Q000201:enzymology / Q000473:pathology*; D012039:Regional Blood Flow / Q000502:physiology; D012782:Shoulder / Q000473:pathology
chemical_list: D009243:NAD; D003576:Electron Transport Complex IV; D000251:Adenosine Triphosphatases