| 1. |
- Carlsson, Lena, et al.
(författare)
-
Myotilin - a prominent marker of myofibrillar remodelling
- 2007
-
Ingår i: Neuromuscular Disorders. - : Elsevier BV. - 0960-8966 .- 1873-2364. ; 17:1, s. 61-68
-
Tidskriftsartikel (refereegranskat)abstract
- Myofibrillar remodelling with insertion of sarcomeres is a typical feature of biopsies taken from persons suffering of exercise-induced delayed onset muscle soreness. Here we studied the presence of the sarcomeric protein myotilin in eccentric exercise related lesions. Myotilin is a component of sarcomeric Z-discs and it binds several other Z-disc proteins, i.e. alpha-actinin, filamin C, F-actin and FATZ. Myotilin has previously been shown to be present in nemaline rods and central cores and to be mutated in limb girdle muscular dystrophy 1A (LGMD1A) and in a subset of myofibrillar myopathies, indicating an important role in Z-disc maintenance. Our findings on non-diseased muscle affected by eccentric exercise give new information on how myotilin is associated to myofibrillar components upon remodelling. We show that myotilin was present in increased amount in lesions related to Z-disc streaming and events leading to insertion of new sarcomeres in pre-existing myofibrils and can therefore be used as a marker for myofibrillar remodelling. Interestingly, myotilin is preferentially associated with F-actin rather than with the core Z-disc protein alpha-actinin during these events. This suggests that myotilin has a key role in the dynamic molecular events mediating myofibrillar assembly in normal and diseased skeletal muscle.
|
|
| 2. |
- Kadi, F., et al.
(författare)
-
The effects of different training programs on the trapezius muscle of women with work-related neck and shoulder myalgia
- 2000
-
Ingår i: Acta Neuropathologica. - Berlin : Springer Berlin/Heidelberg. - 0001-6322 .- 1432-0533. ; 100:3, s. 253-258
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to examine the effects of training on the structural characteristics of the trapezius muscle in women with work-related trapezius myalgia. Muscle biopsies were taken before and after 10 weeks of three different training programs (strength, endurance and coordination). Enzyme-immunohistochemical analysis was performed to assess muscle fibre types, fibre area, capillary supply and cytochrome c oxidase (COX) activity. There was an increase in the proportion of type LIA fibres in strength trained group (P < 0.05). Strength training elicited a preferential increase in the area of type II fibres (P < 0.05); both strength and endurance programs induced an increase in the number of capillaries around type I and IIA muscle fibres. Finally, all training programs induced a decrease in the proportion of COX-negative fibres. In conclusion, the trapezius muscle of women with neck and shoulder myalgia is characterised by a great potential of adaptation to physical exercise over a period of 10 weeks. The significant changes in the number of capillaries and the specific changes induced by training at the level of muscle fibres might well explain the improvement of muscle function.
|
|
| 3. |
- Thornell, Lars-Eric, et al.
(författare)
-
Fibre typing of intrafusal fibres
- 2015
-
Ingår i: Journal of Anatomy. - : John Wiley & Sons. - 0021-8782 .- 1469-7580. ; 227:2, s. 136-156
-
Forskningsöversikt (refereegranskat)abstract
- The first descriptions of muscle spindles with intrafusal fibres containing striated myofibrils and nervous elements were given approximately 150years ago. It took, however, another 100years to establish the presence of two types of intrafusal muscle fibres: nuclear bag and nuclear chain fibres. The present paper highlights primarily the contribution of Robert Banks in fibre typing of intrafusal fibres: the confirmation of the principle of two types of nuclear bag fibres in mammalian spindles and the variation in occurrence of a dense M-band along the fibres. Furthermore, this paper summarizes how studies from the Umea University group (Laboratory of Muscle Biology in the Department of Integrative Medical Biology) on fibre typing and the structure and composition of M-bands have contributed to the current understanding of muscle spindle complexity in adult humans as well as to muscle spindle development and effects of ageing. The variable molecular composition of the intrafusal sarcomeres with respect to myosin heavy chains and M-band proteins gives new perspectives on the role of the intrafusal myofibrils as stretch-activated sensors influencing tension/stiffness and signalling to nuclei.
|
|
