| 1. |
- Lexell, Jan, et al.
(författare)
-
Distribution of different fibre types in human skeletal muscles. A statistical and computational model for the study of fibre type grouping and early diagnosis of skeletal muscle fibre denervation and reinnervation
- 1983
-
Ingår i: Journal of the Neurological Sciences. - 1878-5883 .- 0022-510X. ; 61:3, s. 301-314
-
Tidskriftsartikel (refereegranskat)abstract
- To define fibre type grouping in terms of random and non-random arrangements of the two fibre types, type 1 (ST) and type 2 (FT), we adopted the measure of counting the number of "enclosed fibres". The statistical properties of the number of enclosed fibres, and the number and size of groups of enclosed fibres were studied in computer-simulated muscle cross-sections, using a model based upon hexagonal-shaped fibres. The effects on the results of differences in the sizes of the muscle fibres were considered. The applicability of the model, and the derived results and methods of analysis were tested on 10 samples from a cross-section of a whole human muscle. The results show that the model can be applied to various shapes and sizes of muscle samples and various sizes of muscle fibres. The number of enclosed fibres within a muscle sample is the best of the three measures of non-randomness considered. A test is also described for assessing whether or not the observed number of enclosed fibres is random at a given significance level.
|
|
| 2. |
- Lindman, Rolf, et al.
(författare)
-
Abnormal palatopharyngeal muscle morphology in sleep-disordered breathing
- 2002
-
Ingår i: Journal of the Neurological Sciences. - : Elsevier. - 1878-5883 .- 0022-510X. ; 195:1, s. 11-23
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to investigate whether histopathological changes can be detected in two soft palate muscles, the palatopharyngeus and the uvula, in 11 patients with long duration of sleep-disordered breathing (SDB). Muscle samples were collected froth patients undergoing uvulo-palatopharyngoplasty (UPPP). Reference samples from the corresponding areas were obtained at autopsy froth five previously healthy subjects. Muscle morphology, fibre type and myosin heavy chain (MyHC) compositions were analysed with enzyme-histochemical, immunohistochemical and biochemical techniques. The muscle samples from the patients, and especially those from the palatopharyngeus, showed several morphological abnormalities. The most striking findings were (i) increased amount of connective tissue, (ii) abnormal variability in fibre size, (iii) increased proportion of small-sized fibres, (iv) alterations in fibre type and MyHC compositions, (v) increased frequency of fibres containing developmental MyHC isoforms. Our findings point towards a pathological process of denervation and degeneration in the patient samples. Conclusively. the morphological abnormalities suggest a neuromuscular disorder of the soft palate in SDB patients. (C) 2002 Elsevier Science B.V. All rights reserved.
|
|
| 3. |
- Dahle, Charlotte, et al.
(författare)
-
T helper type 2 like cytokine responses to peptides from P0 and P2 myelin proteins during the recovery phase of Guillain-Barré syndrome
- 1997
-
Ingår i: Journal of the Neurological Sciences. - 0022-510X .- 1878-5883. ; 153:1, s. 54-60
-
Tidskriftsartikel (refereegranskat)abstract
- T-lymphocytes are probably involved in the pathogenesis of Guillain-Barré syndrome (GBS). T-helper-1 (Th1) cytokines activate macrophages and induce a delayed type hypersensitivity (DTH) inflammatory response, consistent with the morphology of the demyelination in GBS. Th2 cytokines encourage antibody production and downregulate Th1 responses. To study the Th1/Th2 cytokines in relation to the clinical course of GBS an ELISPOT method for determination of single cells secreting interferon-γ, IFN-γ (Th1) or interleukin-4, IL-4 (Th2) was used. We serially investigated antigen-induced cytokine secretion from circulating T-cells stimulated with human peptides from the P0 and P2 proteins in seven patients and compared to results from seven serially investigated healthy controls. Most patients (five of seven) showed IL-4 responses during the plateau- or recovery-phase as compared to controls. One patient with a prolonged disease course, on the other hand, had an IFN-γ dominated reactivity. We suggest that the IL-4 responses are beneficial in GBS, and may have a role in terminating the disease process in this self-limiting inflammatory disease.
|
|
| 4. |
- Grundström, Eva, et al.
(författare)
-
Increased expression of glial cell line-derived neurotrophic factor mRNA in muscle biopsies from patients with amyotrophic lateral sclerosis
- 1999
-
Ingår i: Journal of the Neurological Sciences. - 0022-510X .- 1878-5883. ; 162:2, s. 169-173
-
Tidskriftsartikel (refereegranskat)abstract
- The expression of glial cell line-derived neurotrophic factor (GDNF) mRNA and brain-derived neurotrophic factor (BDNF) mRNA were studied in muscle biopsies from five patients with amyotrophic lateral sclerosis (ALS), six patients with other neuromuscular diseases and eight healthy control persons. All five patients with ALS had higher GDNF mRNA expressions in their biopsies than the healthy control group (almost a three fold increase). Among the other patients only one, who had a rapidly progressing toxic polyneuropathy, showed a GDNF mRNA expression above those of the controls. The BDNF mRNA expressions in the biopsies from the ALS patients were in the same range as those from the healthy controls, although the mean value of the ALS patients was higher. The only biopsy that showed a markedly higher BDNF mRNA expression was taken from one patient with progressive muscular atrophy. These results suggest that increased GDNF mRNA expression in muscle is an unspecific response to ongoing denervation and that this response is maintained in ALS, at least temporarily. If increased GDNF mRNA in muscle proves to be a constant finding in ALS the rationale for the use of GDNF as a therapeutic agent in ALS must be questioned.
|
|
| 5. |
- Lexell, Jan, et al.
(författare)
-
Distribution of different fibre types in human skeletal muscles : A statistical and computational study of the fibre type arrangement in m. vastus lateralis of young, healthy males
- 1984
-
Ingår i: Journal of the Neurological Sciences. - 0022-510X .- 1878-5883. ; 65:3, s. 353-365
-
Tidskriftsartikel (refereegranskat)abstract
- To test whether the arrangement of fibre types in the human muscle (m. vastus lateralis) from clinically healthy and young males can be regarded as random, fascicles at different parts of the muscle and with different fibre type proportions were studied. The randomness of the arrangement of fibre types was assessed by the number of enclosed fibres in a fascicle and, on the basis of a model, tested by simulating muscle cross-sections using a microcomputer. The fibre type proportion was found to vary within a fascicle, so the original model for the test of randomness was modified to allow for different fibre type proportions on the border of the fascicle and internally. The effect of different sizes of the fibre types was also considered. The various aspects considered had only a marginal effect on the original model. For this muscle (m. vastus lateralis) the arrangement of fibre types was therefore considered random. Thus, a sample from this muscle, taken from individuals of the same sex and age group, can be tested for non-randomness, as an indication of a successive denervation and reinnervation process
|
|
| 6. |
- Lexell, Jan, et al.
(författare)
-
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
-
Ingår i: Journal of the Neurological Sciences. - 0022-510X .- 1878-5883. ; 72:2-3, s. 211-222
-
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.
|
|
| 7. |
|
|
| 8. |
- Lexell, Jan, et al.
(författare)
-
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
-
Ingår i: Journal of the Neurological Sciences. - 0022-510X .- 1878-5883. ; 84:2-3, s. 275-294
-
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
|
|
| 9. |
|
|
| 10. |
- Libelius, Rolf, et al.
(författare)
-
Uptake of horseradish peroxidase in denervated skeletal muscle occurs primarily at the endplate region
- 1984
-
Ingår i: Journal of the Neurological Sciences. - 0022-510X .- 1878-5883. ; 66, s. 273-281
-
Tidskriftsartikel (refereegranskat)abstract
- The spatial distribution of horseradish peroxidase (HRP) uptake has been studied by light- and electron microscopy in the denervated hemidiaphragm of the mouse. Segments with high HRP uptake were observed in a band centrally located in the denervated muscle. This distribution is similar to the well-known innervation pattern of the diaphragm. Ultrastructural studies demonstrated a high incidence of postsynaptic folds in close proximity of fibre areas with high intracellular content of HRP. 8–12 days after denervation a large number of fibres showed segments of high HRP uptake. 2–4 days after denervation very few such segments were observed. Biochemical studies also demonstrated an increase in HRP uptake after denervation occurring primarily in the endplate region. The activities of the lysosomal enzymes N-acetyl-β-d-glucosaminidase, acid phosphatase and cathepsin D all increased after denervation, most prominently in the endplate region.It is suggested that the observed segmental uptake of HRP and lysosomal activation reflects a process for rapid membrane turnover in denervated muscle.
|
|
