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- Lindström, Mona, et al.
(författare)
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Pax7-Positive Cells/Satellite Cells in Human Extraocular Muscles
- 2015
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Ingår i: Investigative Ophthalmology and Visual Science. - : Association for Research in Vision and Ophthalmology (ARVO). - 0146-0404 .- 1552-5783. ; 56:10, s. 6132-6143
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE. We quantified and investigated the distribution of Pax7-positive cells/satellite cells (SCs) in the human extraocular muscles (EOMs). METHODS. An immunofluorescence multiple-marker method simultaneously combining two SC markers (Pax7, NCAM), detection of the basement membrane (laminin) and cell nuclei (4',6-diamidino-2-phenylindole [DAPI]), was used on the anterior, middle, and posterior portions of EOMs from five healthy donors. Pax7-positive cell and SC content, myonuclear content, myofiber cross-sectional area, and myonuclear domain were analyzed in single cross-sections. Between 3915 and 13,536 myofibers per muscle cross-section and myofibers from the entire EOM cross-section were analyzed for quantification of Pax7-positive cells per myofiber (Pax7/F).RESULTS. The number of Pax7/F in the human EOMs varies along the length of the muscle with twice as high Pax7/F in the anterior part of the EOMs, but within the range of what has been previously reported for normal adult limb muscles. Furthermore, there are Pax7-positive cells in positions other than the classical SC position and the myonuclear domain size of adult EOMs is noticeably smaller than that previously reported for other adult skeletal muscles.CONCLUSIONS. Previous data on differences in Pax7-positive cell/SC abundance between EOMs and limb muscles must be reconsidered and the characteristics of different Pax7-positive cell populations further investigated. Higher numbers of Pax7-positive cells in the anterior portion of the EOMs may have a bearing for strabismus surgery involving sectioning of the muscle fibers.
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| 2. |
- Nilipour, Yalda, et al.
(författare)
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Ryanodine receptor type 3 (RYR3) as a novel gene associated with a myopathy with nemaline bodies
- 2018
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Ingår i: European Journal of Neurology. - : Blackwell Publishing. - 1351-5101 .- 1468-1331. ; 25:6, s. 841-847
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Tidskriftsartikel (refereegranskat)abstract
- Background: Nemaline myopathy has been associated with mutations in twelve genes to date. However, for some patients diagnosed with nemaline myopathy, definitive mutations are not identified in the known genes, suggesting there are other genes involved. This study describes compound heterozygosity for rare variants in RYR3 in one such patient.Results: Clinical examination of the patient at 22 years of age revealed a long-narrow face, high arched palate and bilateral facial weakness. She had proximal weakness in all four limbs, mild scapular winging but no scoliosis. Muscle biopsy revealed wide variation in fibre size with type 1 fibre predominance and atrophy. Abundant nemaline bodies were located in perinuclear areas, subsarcolemmal and within the cytoplasm. No likely pathogenic mutations in known nemaline myopathy genes were identified. Copy number variation in known nemaline myopathy genes was excluded by nemaline myopathy targeted array-CGH. Next generation sequencing revealed compound heterozygous missense variants in the ryanodine receptor type 3 gene (RYR3). RYR3 transcripts are expressed in human fetal and adult skeletal muscle as well as in human brain or cauda equina samples. Immunofluorescence of human skeletal muscle revealed a "single-row" appearance of RYR3, interspaced between the "double-rows" of RYR1 at each A-I junction.Conclusion: The results suggest that variants in RYR3 may cause a recessive muscle disease with pathological features including nemaline bodies. We characterize the expression pattern of RYR3 in human skeletal muscle and brain and the subcellular localization of RYR1 and RYR3 in human skeletal muscle.
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| 3. |
- Tjust, Anton E., et al.
(författare)
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Impact of Amyotrophic Lateral Sclerosis on Slow Tonic Myofiber Composition in Human Extraocular Muscles
- 2017
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Ingår i: Investigative Ophthalmology and Visual Science. - : ASSOC RESEARCH VISION OPHTHALMOLOGY INC. - 0146-0404 .- 1552-5783. ; 58:9, s. 3708-3715
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE. To analyze the proportion and cross-sectional area of myofibers containing myosin heavy chain slow-twitch (MyHCI) and myosin heavy chain slow tonic (MyHCsto) in extraocular muscles of autopsied amyotrophic lateral sclerosis (ALS) patients with either spinal or bulbar site of disease onset. METHODS. Whole-muscle cross sections from the middle portion of the medial rectus were labeled with antibodies against MyHCI or MyHCsto and laminin. Myofibers labeled with the MyHC antibodies (MyHCI+sto) and the total number of myofibers were quantified in the orbital and global layer of 6 control individuals and 18 ALS patients. The cross-sectional area of myofibers labeled for either MyHC was quantified in 130 to 472 fibers/individual in the orbital and in 180 to 573 fibers/individual in the global layer of each specimen. RESULTS. The proportion of MyHCI+sto myofibers was significantly smaller in the orbital and global layer of ALS compared to control individuals. MyHCI+sto myofibers were significantly smaller in the global layer than in the orbital layer of ALS, whereas they were of similar size in control subjects. The decreased proportion of MyHCI+sto fibers correlated significantly with the age of death, but not disease duration, in patients who had the bulbar-onset variant of ALS but not in patients with spinal variant. CONCLUSIONS. ALS, regardless of site of onset, involves a loss of myofibers containing MyHCI+sto. Only in bulbar-onset cases did aging seem to play a role in the pathophysiological processes underlying the loss of MyHCI+sto fibers.
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