title: Internalized myofiber capillaries: observations on their origin and clinical features.
abstract: Internalized capillaries limited to type 1 muscle fibers were noted in seven patients. They occurred in each case in association with a similar admixture of neurogenic and myopathic features that included atrophic and hypertrophic fibers, internal nuclei, fiber splitting, and endomyseal and perimyseal fibrosis. Internalized capillaries in enlarged type 1 fibers arose from fiber splits on step section study of four patients. They occurred in the gastrocnemius, quadriceps, and soleus muscles from patients with a variety of disorders that included Becker dystrophy, diabetes mellitus and strenuous leg activities, Achilles tendon rupture, and myotonic dystrophy. Exercise-induced myalgias were noted in the four patients with the most plentiful intramuscular capillaries, and in three of these muscle hypertrophy was present. The concurrence of internalized myofiber capillaries and exercise-induced myalgias may represent an associated biochemical/pathological defect.
authors.affiliation: Department of Neurology, West Virginia University School of Medicine, Morgantown 26506.
authors.forename: L
authors.initials: L
authors.lastname: Gutmann
authors.forename: R
authors.initials: R
authors.lastname: Wolf
authors.forename: W
authors.initials: W
authors.lastname: Nix
authors.forename: H H
authors.initials: HH
authors.lastname: Goebel
authors.forename: S S
authors.initials: SS
authors.lastname: Schochet
authors.forename: H C
authors.initials: HC
authors.lastname: Hopf
authors.forename: G
authors.initials: G
authors.lastname: Kramer
mesh_terms: D000293:Adolescent; D000328:Adult; D002196:Capillaries / Q000473:pathology*; D003922:Diabetes Mellitus, Type 1 / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009132:Muscles / Q000098:blood supply* / Q000648:ultrastructure; D009135:Muscular Diseases / Q000473:pathology*; D009223:Myotonic Dystrophy / Q000473:pathology; D011446:Prospective Studies; D012421:Rupture; D013708:Tendon Injuries / Q000473:pathology