| 1. |
- Lexell, Jan, et al.
(författare)
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Distribution of different fibre types in human skeletal muscles : fibre type arrangement in m. vastus lateralis from three groups of healthy men between 15 and 83 years
- 1986
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Ingår i: Journal of the Neurological Sciences. - 0022-510X .- 1878-5883. ; 72:2-3, s. 211-222
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Tidskriftsartikel (refereegranskat)abstract
- The effects of age on the fibre type arrangement in the human muscle m. vastus lateralis were studied. There were 10, 6 and 8 healthy men in the three age-groups with means 24, 52 and 77 years, respectively. For each fascicle considered, the numbers of type 1 (ST) and type 2 (FT) fibres on the boundary and internally, and the numbers of enclosed fibres of either type, were counted. The randomness of the fibre type arrangement was considered in terms of the numbers of enclosed fibres and assessed by a Monte Carlo significance test. Fibre type grouping was shown to increase with increasing age. The proportion of type 2 fibres on the boundary of a fascicle was consistently greater than internally, but the difference was less pronounced in the old group. It is argued that the process of denervation and reinnervation of individual fibres has started before the age of 50, is a major factor in a progressive reduction of fibres with increasing age and is probably caused by a continuous loss of motor neurons in the spinal cord.
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| 2. |
- Lexell, Jan, et al.
(författare)
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What is the cause of the ageing atrophy? : number, size and proportion of different fiber types studied in whole vastus lateralis muscle from 15- to 83-year-old men
- 1988
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Ingår i: Journal of the Neurological Sciences. - 0022-510X .- 1878-5883. ; 84:2-3, s. 275-294
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Tidskriftsartikel (refereegranskat)abstract
- In order to study the effects of increasing age on the human skeletal muscle, cross-sections (15 micron) of autopsied whole vastus lateralis muscle from 43 previously physically healthy men between 15 and 83 years of age were prepared and examined. The data obtained on muscle area, total number, size, proportion and distribution of type 1 (slow-twitch) and type 2 (fast-twitch) fibers were analysed using multivariate regression. The results show that the ageing atrophy of this muscle begins around 25 years of age and thereafter accelerates. This is caused mainly by a loss of fibers, with no predominant effect on any fiber type, and to a lesser extent by a reduction in fiber size, mostly of type 2 fibers. The results also suggest the occurrence of several other age-related adaptive mechanisms which could influence fiber sizes and fiber number, as well as enzyme histochemical fiber characteristics
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| 3. |
- Strigård, Karin, et al.
(författare)
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Modulation of experimental allergic neuritis in rats by in vivo treatment with monoclonal anti T cell antibodies.
- 1988
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Ingår i: Journal of the Neurological Sciences. - 0022-510X .- 1878-5883. ; 83:2-3
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Tidskriftsartikel (refereegranskat)abstract
- Monoclonal antibodies (MCA) to different T lymphocyte cell surface antigens have been used to treat rats during different phases of the development of experimental allergic neuritis (EAN). The effects of this treatment were followed by clinical evaluation and in some instances by immunohistochemical analysis of lymphoid organs and affected nerves of the antibody-treated rats. Several MCA, W3/13 (pan T cell reactive), W3/25 (anti-rat CD4), Ox 8 (anti-rat CD8) as well as Ox 6 (anti-Ia) partly prevented clinical signs of EAN when given shortly before expected onset of disease, whereas W3/13 and Ox 8 given at the height of disease did not further affect disease development. However, Ox 19 (anti-rat CD5) given at the same time as immunization partly prevented clinical signs of EAN, while Ox 19 given shortly before expected onset of disease or during height of disease drastically exaggerated disease symptoms. Immunohistochemical studies after Ox 8 or Ox 19 treatment showed a complete absence of staining for the respective antibodies, while staining was preserved with the other MCA. It is concluded that: (1) Ox 8 positive "suppressor/cytotoxic" T lymphocytes do not exert any suppressive effects on EAN during the now investigated phases of disease, and that (2) anti T lymphocyte antibodies (here Ox 19) may exert opposite effects on autoimmune disease when given at different phases of disease development. This may have implications for potential therapeutic trials of MCA therapy for putative autoimmune demyelinating diseases in man.
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| 4. |
- Tågerud, Sven, et al.
(författare)
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An ultrastructural study of the segmental uptake of horseradish peroxidase in the endplate region of denervated skeletal muscle fibres
- 1986
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Ingår i: Journal of the Neurological Sciences. - 0022-510X .- 1878-5883. ; 75:2, s. 141-157
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Tidskriftsartikel (refereegranskat)abstract
- The segmental uptake of horseradish peroxidase (HRP) in the endplate region of denervated skeletal muscle fibres has been studied ultrastructurally using a method for selecting single muscle fibres with high segmental peroxidase staining from denervated mouse tibialis anterior muscle.Segments containing large peroxidase positive phagosomes could already be seen 10–15 min after i.v. injection of HRP. Such segments were still present 24 h after HRP injection. The localization of phagosomes, deep in the fibres rather than immediately under the sarcolemma, suggests that the uptake occurs from t-tubuli. Vivid proliferation of t-tubuli, consisting of vesiculation, enlargement and encircling of cytoplasmic components, was also observed. The HRP accumulates in phagosomes of varying size and shape. Similar membrane-limited bodies without or with very weak peroxidase staining were also observed. The peroxidase-positive phagosomes participate in autophagic processes as suggested by their content of undegraded cellular material. Golgi profiles, which occurred deep in the muscle fibres, and enlarged components of the sarcoplasmic reticulum were frequently encountered in the segments. Myofibrillar degeneration occurs in the segments and progresses with time after denervation.The described segments may be related to the increased membrane turnover in denervated muscle fibres and/or they may be related to processes aimed at establishing new synaptic contacts.
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| 5. |
- Tågerud, Sven, et al.
(författare)
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Biochemical and ultrastructural effects of chloroquine on horseradish peroxidase uptake and lysosomal enzyme activities in innervated and denervated mouse skeletal muscle
- 1986
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Ingår i: Journal of the Neurological Sciences. - 0022-510X .- 1878-5883. ; 75:2, s. 159-171
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Tidskriftsartikel (refereegranskat)abstract
- The effects of chloroquine treatment on horseradish peroxidase (HRP) uptake and lysosomal enzyme activities in innervated and denervated mouse skeletal muscle have been studied using biochemical, histochemical and ultrastructural techniques.Chloroquine treatment caused a large (59–101%) increase in the activity of cathepsin D in both innervated and denervated muscle. The activity of N-acetyl-β-d-glucosaminidase also increased slightly in denervated muscle. No effect was observed on acid phosphatase activity. The in vivo uptake of HRP in innervated and denervated muscle was unaffected by chloroquine treatment. The results show that the activities of certain lysosomal enzymes may increase in skeletal muscle without an increase in endocytic activity. This is discussed in comparison to what is seen in denervated and dystrophic muscle.Histochemical and ultrastructural studies showed the HRP uptake to occur segmentally in denervated muscle fibres from untreated as well as chloroquine-treated animals. Ultrastructurally the peroxidase-positive phagosomes occurring in these segments were found to contain increased levels of undegraded material after chloroquine treatment suggesting that these phagosomes are of a lysosomal nature and also participate in autophagic processes.
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| 6. |
- Zachau, A C, et al.
(författare)
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Distribution of plasma cells secreting antibodies against nervous tissue antigens during experimental allergic encephalomyelitis enumerated by a nitrocellulose immunospot assay.
- 1989
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Ingår i: Journal of the Neurological Sciences. - 0022-510X .- 1878-5883. ; 91:3, s. 323-336
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Tidskriftsartikel (refereegranskat)abstract
- The B cell response to central nervous system (CNS) myelin and myelin basic protein, as well as total numbers of IgG secreting cells, was studied in acute experimental allergic encephalomyelitis using a nitrocellulose immunospot assay. The method was able to detect single plasma cells secreting antibodies. Cells secreting antibodies against myelin antigens were detected in regional lymph node cell suspension by day 5 post-immunization (p.i.). At that time no anti-myelin antibodies were detected free in serum. Later, at day 15 p.i., specific antibody secreting cells were found in bone marrow and spleen indicating a generalization of the immune response. The B cell response became partly sequestered to the target of immune attack since an increased number of IgG secreting cells was detected among mononuclear cells recovered from the CNS. Studies of cellular secretion of antibodies rather than free levels in body fluids may be a more accurate reflection of the in vivo B cell response. These findings may be generally considered in studies of B cell mediated immunity in neuroinflammatory diseases.
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