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  • 1
    Electronic Resource
    Electronic Resource
    Immunohistochemical study of calpain and its endogenous inhibitor in the skeletal muscle of muscular dystrophy (1995)
    Springer
    Acta neuropathologica 89 (1995), S. 399-403 
    Details
    ISSN: 1432-0533
    Keywords: Key words Calpain ; Calpastatin ; Muscular dystrophy ; Neuromuscular diseases ; Normal human muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A calcium-dependent proteinase (calpain) has been suggested to play an important role in muscle degradation in Duchenne muscular dystrophy (DMD). In immunohistochemical studies, calpain and its endogenous inhibitor (calpastatin) were located exclusively in the cytoplasm in normal human muscles. The intensity of the staining was stronger in type 1 than in type 2 fibers. Quantitative immunohistochemical study showed an increase of calpain in biopsied muscles from the patients with DMD and Becker muscular dystrophy. Abnormal increases in calpain and calpastatin were demonstrated mainly in atrophic fibers, whereas necrotic fibers showed moderate or weak immunoreactions for the enzymes. Opaque fibers and hypertrophic fibers were negative. Not all dystrophin-deficient muscle fibers necessarily showed a strong reaction for calpain. We suggest that calpain may play an important role in muscle fiber degradation, especially in the early stage of muscle degradation in muscular dystrophy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307642
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Immunohistochemical study of clathrin in distal myopathy with rimmed vacuoles (1998)
    Springer
    Acta neuropathologica 95 (1998), S. 571-575 
    Details
    ISSN: 1432-0533
    Keywords: Key words Distal myopathy ; Rimmed vacuole ; Clathrin ; Lysosome ; Coated vesicle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Clathrin-coated vesicles are involved in three receptor-mediated intracellular transport pathways: export from the Golgi apparatus, transfer of lysosomal enzymes from the Golgi apparatus to lysosomes, and endocytosis at the plasma membrane. Seeking evidence of transport abnormalities in distal myopathy with rimmed vacuoles (DMRV), we performed immunohistochemistry for clathrin in muscle biopsy specimens from patients with this disorder or other neuromuscular disorders, and also in control muscle samples resected in orthopedic procedures. While most myofibers from control muscle did not stain for clathrin, some fibers revealed finely granular sarcoplasmic staining. In specimens from patients with Duchenne and Becker muscular dystrophy, amyotrophic lateral sclerosis, peripheral neuropathy, and DMRV, numerous clathrin-positive granules were often scattered through the sarcoplasm and seen to a lesser extent in subsarcolemmal regions. Quantitative immunohistochemical assessment showed more reactivity for clathrin in DMRV than in controls and other diseased muscles, particularly in atrophic fibers and type 2 fibers. Not all strongly clathrin-positive muscle fibers contained rimmed vacuoles, although most fibers with vacuoles were clathrin positive. The result suggests that the lysosome system is activated and receptor-mediated intracellular transport pathways function appropriately in the muscles of DMRV patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004010050842
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Muscle fiber degradation in distal myopathy with rimmed vacuoles (1994)
    Springer
    Acta neuropathologica 87 (1994), S. 143-148 
    Details
    ISSN: 1432-0533
    Keywords: Distal myopathy ; Rimmed vacuole ; Lysosome ; Muscle degradation ; Calpain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Late-onset distal myopathy showed numerous rimmed vacuoles with the same properties as autophagic vacuoles. Electron microscopy showed numerous degenerated mitochondria, glycogen, or cell membranes in rimmed vacuoles, but no evidence that these vacuoles engulfed and contained intact or partially disrupted myofibrils. Immunostaining for myosin, α-actinin, and actin, however, was sometimes positive within the vacuoles. Compared to the control muscle, there was increased staining activity by calpain around the rimmed vacuoles or in the cytoplasm of mainly atrophic fibers. The result seems to indicate an increase of calpain activity in these muscle fibers. We hypothesize that the myofibrils as well as mitochondria, glycogen, or cell membranes in this myopathy are degraded finally through a lysosomal autophagic process. However, the breakdown of the myofibrils may be not initiated by lysosomal activation; rather it may be the result of extralysosomal processes such as the calpain system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296183
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Muscle fiber degradation in distal myopathy with rimmed vacuoles (1994)
    Springer
    Acta neuropathologica 87 (1994), S. 143-148 
    Details
    ISSN: 1432-0533
    Keywords: Key words: Distal myopathy – Rimmed vacuole – Lysosome – Muscle degradation – Calpain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Late-onset distal myopathy showed numerous rimmed vacuoles with the same properties as autophagic vacuoles. Electron microscopy showed numerous degenerated mitochondria, glycogen, or cell membranes in rimmed vacuoles, but no evidence that these vacuoles engulfed and contained intact or partially disrupted myofibrils. Immunostaining for myosin, α-actinin, and actin, however, was sometimes positive within the vacuoles. Compared to the control muscle, there was increased staining activity by calpain around the rimmed vacuoles or in the cytoplasm of mainly atrophic fibers. The result seems to indicate an increase of calpain activity in these muscle fibers. We hypothesize that the myofibrils as well as mitochondria, glycogen, or cell membranes in this myopathy are degraded finally through a lysosomal autophagic process. However, the breakdown of the myofibrils may be not initiated by lysosomal activation; rather it may be the result of extralysosomal processes such as the calpain system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296183
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Immunohistochemical study of calpain and its endogenous inhibitor in the skeletal muscle of muscular dystrophy (1995)
    Springer
    Acta neuropathologica 89 (1995), S. 399-403 
    Details
    ISSN: 1432-0533
    Keywords: Calpain ; Calpastatin ; Muscular dystrophy ; Neuromuscular diseases ; Normal human muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A calcium-dependent proteinase (calpain) has been suggested to play an important role in muscle degradation in Duchenne muscular dystrophy (DMD). In immunohistochemical studies, calpain and its endogenous inhibitor (calpastatin) were located exclusively in the cytoplasm in normal human muscles. The intensity of the staining was stronger in type 1 than in type 2 fibers. Quantitative immunohistochemical study showed an increase of calpain in biopsied muscles from the patients with DMD and Becker muscular dystrophy. Abnormal increases in calpain and calpastatin were demonstrated mainly in atrophic fibers, whereas necrotic fibers showed moderate or weak immunoreactions for the enzymes. Opaque fibers and hypertrophic fibers were negative. Not all dystrophin-deficient muscle fibers necessarily showed a strong reaction for calpain. We suggest that calpain may play an important role in muscle fiber degradation, especially in the early stage of muscle degradation in muscular dystrophy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307642
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Proteasome expression in the skeletal muscles of patients with muscular dystrophy (2000)
    Springer
    Acta neuropathologica 100 (2000), S. 595-602 
    Details
    ISSN: 1432-0533
    Keywords: Key words Duchenne and Becker muscular dystrophies ; Muscle biopsy specimens ; Proteasomes ; Ubiquitin ; Calpain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Previous investigators have suggested that proteolysis by calpain, a Ca2+-dependent protease, causes muscle fiber degradation in Duchenne and Becker muscular dystrophies (DMD/BMD). Recent evidence indicates that the nonlysosomal ATP-ubiquitin-dependent proteolytic complex (proteasomes) participates in muscle wasting during various catabolic states and in muscle fiber degradation in physiological or pathological conditions. To elucidate the possible role of proteasomes in dystrophic muscles, routine histochemistry and immunohistochemistry of 26S proteasomes were performed on muscle biopsy specimens obtained from patients with various neuromuscular disorders including DMD/BMD, polymyositis (PM), amyotrophic lateral sclerosis, and peripheral neuropathies, and on normal human muscle specimens. Immunohistochemically, proteasomes were located in the cytoplasm in normal human muscle, but their staining intensity was faint. Compared to control muscles, abnormal increases in both proteasomes and ubiquitin were demonstrated mainly in the cytoplasm of necrotic fibers and to a lesser extent in regenerative fibers in DMD/BMD and PM. Non-necrotic, atrophic fibers in all diseased muscles showed moderate or weak immunoreactions for the proteins; their staining intensities were stronger than those of control muscle fibers. Both proteins often colocalized well. Not all dystrophin-deficient muscle fibers showed a strong reaction for proteasomes. Our results showed increased proteasomes in necrotic and regenerative muscle fibers in DMD/ PMD, although this may not be disease-specific up-regulation. We suggest that the ATP-ubiquitin-dependent proteolytic pathway as well as the nonlysosomal calpain pathway may participate in muscle fiber degradation in muscular dystrophy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004010000229
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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