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- Edman, Anne-Christine, 1946-
(författare)
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Myofibrillens finstruktur i tvärstrimmig skelettmuskulatur
- 1988
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The detailed structure of the myofibrillar material in fibres from different muscles has been studied. Specimens have been obtained from human muscles and from different muscles frequently examined in experimental studies. Both light- and electron microscopical techniques have been used. Of central importance has been the method, which makes it possible to prepare ultrathin sections of frozen tissue, i.e. cryo-ult- ramicrotomy. A number of techniques for image analysis have been applied in order to obtain objektive data from the micrographs.In Paper I the present knowledge about muscle fibre structure, cryo-- sectioning and image analysis is summarized and relevant methodological problems are discussed. Paper II describes the detailed structure of the C-zone of the A-band and shows, above all, that structures occur with different repeats along the long axis of the myofibril. Paper III describes the subcellular organization of different fibres in a homogeneous (based on enzyme histochemical mATPase) population, and shows that different structural characteristies can vary independently of each other. Paper IV describes the structural diversity of the myofibrillar M-band, and paper V the diversity of the myofilament fine structure in different fibres. The results show that there is a most sophisticated, and previosly unrealized, structural specialization both within the myofibrils and between myofibrils from different fibres and muscles, even if the fibres are of the same fibre type. The findings suggest that generally used models, showing the structural organization within myofibrils and myofilaments, are oversimplifications. The fibre population is more heterogeneously built up than the common systems for fibre type classification makes one to belive.
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| 2. |
- Edman, Anne-Christine, et al.
(författare)
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Structural diversity in muscle fibres of chicken breast
- 1988
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Ingår i: Cell and Tissue Research. - 0302-766X .- 1432-0878. ; 251:2, s. 281-289
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Tidskriftsartikel (refereegranskat)abstract
- hicken breast muscle is usually considered to be a relatively homogeneous white muscle and has therefore been widely used for studies of muscle proteins. In a previous study, however, we have found different M-region structures in different fibres from this muscle. Because of this result, we have now carried out a combined histochemical and ultrastructural survey of this muscle. In particular, we have made use of large transverse cryo-sections that include most of the muscle cross-section. Although the white region is fairly homogeneous in fibre content according to normal histochemical criteria (mATPase), we have found that there is a gradation of fibre structure across the muscle. The bulk of the muscle stains conventionally for Type-II fibres according to mATPase tests (the "white" part) but, in the small "red" part of the muscle, there are also Type-I fibres together with the Type-II fibres. Superimposed on this division into Type-I and Type-II fibres are variations in fibre size, oxidative and glycolytic staining properties, and variations of Z-band width and M-band structure; there is no strict correlation among any of these parameters. The apparently uniform staining across most of the muscle when tested for myofibrillar ATPase may be a misleading indicator of fibre properties.
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