HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Correspondence: Submit a response Alert me when this article is cited Alert me when Correspondence are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lotz, B. P. Articles by Engel, A. G. Search for Related Content PubMed PubMed Citation Articles by Lotz, B. P. Articles by Engel, A. G.

Are hypercontracted muscle fibers artifacts and do they cause rupture of the plasma membrane?

Department of Neurology and Neuromuscular Research Laboratory, Maya Clinic, Rochester, MN.

Muscle fibers with hypercontracted zones (contractures) and plasma membrane defects are relatively frequent in Duchenne dystrophy, but artifacts might account for either. To investigate the problem further, we determined the frequency of hypercontracted muscle fibers in longitudinal, trichrome-stained paraffin sections in 143 muscle biopsy specimens in a wide variety of muscle diseases. The specimens were held at rest length during fixation. The incidence of hypercontracted fibers in Duchenne dystrophy was significantly higher than in any of the other diseases or in normal controls. We also induced contractures in rat muscle by fixation without restraint, electrical stimulation, and cutting the muscle fibers in vivo. Electron-microscopy showed no plasma membrane defects associated with the contractures, except in the cut fibers within 25 µm of their cut ends, which were probably overloaded with calcium. The results indicate that (1) in Duchenne dystrophy the contractures in muscle fibers held at rest length during fixation cannot be accounted for by artifact; (2) contractures occurring in normal muscle during fixation do not in and of themselves cause rupture of the muscle fiber plasma membrane.

Address correspondence and reprint requests to Dr. Engel, Maya Clinic, Rochester, MN 55905.

Supported by NIH Grant NS6277, a Research Center Grant from the Muscular Dystrophy Association, and by the Mogg Fund.

Received December 5, 1986. Accepted for publication in final form December 30, 1986.

This article has been cited by other articles:

				D. R. Claflin and S. V. Brooks Direct observation of failing fibers in muscles of dystrophic mice provides mechanistic insight into muscular dystrophy Am J Physiol Cell Physiol, February 1, 2008; 294(2): C651 - C658. [Abstract] [Full Text] [PDF]

				D. J. Blake, A. Weir, S. E. Newey, and K. E. Davies Function and Genetics of Dystrophin and Dystrophin-Related Proteins in Muscle Physiol Rev, April 1, 2002; 82(2): 291 - 329. [Abstract] [Full Text] [PDF]