Longitudinal Fibre Splitting in Neurogenic Muscular Disorders—its Relation to the Pathogenesis of ‘Myopathic’ Change

Schwartz, Martin S.; Sargeant, Margaret K.; Swash, Michael

doi:10.1093/brain/99.4.617

Cited by 57 publications

(37 citation statements)

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“…There was no evidence of denervation in the control material. Myopathic changes, such as those found in these biopsies, are well recognised in long-standing denervation (Drachman et al, 1967) and there is evidence that these changes may be the result of mechanical trauma and of attempts at regeneration induced by normal loads imposed on a weakened muscle (Schwartz et al, 1976).…”

Section: Discussionmentioning

confidence: 88%

Sphincter denervation in anorectal incontinence and rectal prolapse.

Parks¹,

Swash²,

Urich³

1977

Gut

505

136

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SUMMARY Biopsies of the external anal sphincter, puborectalis, and levator ani muscles have been examined in 24 women and one man with long-standing anorectal incontinence, 18 of whom also had rectal prolapse, and in two men with rectal prolapse alone. In 16 of the women anorectal incontinence was of unknown cause, but in eight there was a history of difficult labour. Similar biopsies were examined in six control subjects. In all the incontinent patients there was histological evidence of denervation, which was most prominent in the external anal sphincter muscle biopsies, and least prominent in the levator ani muscles. Myopathic features, which were thought to be secondary, were present in the more abnormal biopsies. There were severe histological abnormalities in small nerves supplying the external anal sphincter muscle in the three cases in which material was available for study. We suggest that idiopathic anorectal incontinence may be the result of denervation of the muscles of the anorectal sling, and of the anal sphincter mechanism. This could result from entrapment or stretch injury of the pudendal or perineal nerves occurring as a consequence of rectal descent induced during repeated defaecation straining, or from injuries to these nerves associated with childbirth.Faecal incontinence occurs in patients with various neurological disorders, particularly with spinal cord and lumbosacral root lesions, after trauma to the muscles of the pelvic floor (Parks and McPartlin, 1971), in association with rectal prolapse (Porter, 1962), and as an idiopathic disorder (Parks, 1975). Anorectal incontinence, a term used to denote faecal incontinence not caused by neurological disorders, occurs in about two-thirds of patients with rectal prolapse referred for operation, but a third of these remain incontinent after rectopexy, and these patients are then similar to those with idiopathic anorectal incontinence. The latter disorder occurs almost exclusively in women. These patients usually complain of a disturbance of anorectal sensation so that they are unable to differentiate flatus from faeces, though formal sensory examination of the skin of the anal margin reveals no abnormality, and the tendon reflexes in the legs are preserved. The rectal sphincter is commonly patulous, there is little if any voluntary sphincter contraction, and the anal reflex is usually absent. The normal anorectal angle 1Address for correspondence: The London Hospital (Whitechapel), London El IBB.

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Section: Discussionmentioning

confidence: 88%

Sphincter denervation in anorectal incontinence and rectal prolapse.

Parks¹,

Swash²,

Urich³

1977

Gut

505

136

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show abstract

“…The paper by Schwartz et al, 1976, throws further light on the role of the nucleus in fiber branching. They used the electron microscope to look at early phase fiber branching and found that a zone of separation of myofibrils was often in close relation to a central nucleus.…”

Section: Some Observations On Branch Formation In Human Myopahtiesmentioning

confidence: 97%

“…In the 20 th century there have been reports by Greenfield et al 1957;Adams et al 1962;Pearce & Walton 1962;Bell and Conen 1968;Schwartz et al 1976;Swash et al 1977;Schmalbruch 1984 andHamida et al 1992.…”

Section: The Long History Of Branched Fiber Reports In Human Dystrophiesmentioning

confidence: 99%

A Two Stage Model of Skeletal Muscle Necrosis in Muscular Dystrophy - The Role of Fiber Branching in the Terminal Stage

Head¹

2012

Muscular Dystrophy

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“…S5A), a feature common to many muscle pathologies, including CCD (21), and inward folding of the external surface membrane in EDL (Fig. S5B), which is often associated with fiber splitting in neurogenic and myopathic disorders (22). …”

Section: )mentioning

confidence: 99%

Characterization and temporal development of cores in a mouse model of malignant hyperthermia

Boncompagni

Rossi

Micaroni

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

100

126

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Malignant hyperthermia (MH) and central core disease are related skeletal muscle diseases often linked to mutations in the type 1 ryanodine receptor (RYR1) gene, encoding for the Ca 2؉ release channel of the sarcoplasmic reticulum (SR). In humans, the Y522S RYR1 mutation is associated with malignant hyperthermia susceptibility (MHS) and the presence in skeletal muscle fibers of core regions that lack mitochondria. In heterozygous Y522S knock-in mice (RYR1 Y522S/WT ), the mutation causes SR Ca 2؉ leak and MHS. Here, we identified mitochondrial-deficient core regions in skeletal muscle fibers from RYR1 Y522S/WT knock-in mice and characterized the structural and temporal aspects involved in their formation. Mitochondrial swelling/disruption, the initial detectable structural change observed in young-adult RYR1 Y522S/WT mice (2 months), does not occur randomly but rather is confined to discrete areas termed presumptive cores. This localized mitochondrial damage is followed by local disruption/loss of nearby SR and transverse tubules, resulting in early cores (2-4 months) and small contracture cores characterized by extreme sarcomere shortening and lack of mitochondria. At later stages (1 year), contracture cores are extended, frequent, and accompanied by areas in which contractile elements are also severely compromised (unstructured cores). Based on these observations, we propose a possible series of events leading to core formation in skeletal muscle fibers of RYR1 Y522S/WT mice: Initial mitochondrial/SR disruption in confined areas causes significant loss of local Ca 2؉ sequestration that eventually results in the formation of contractures and progressive degradation of the contractile elements.central core disease ͉ excitation-contraction coupling ͉ muscle disease ͉ ryanodine receptor ͉ mitochondria

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Longitudinal Fibre Splitting in Neurogenic Muscular Disorders—its Relation to the Pathogenesis of ‘Myopathic’ Change

Cited by 57 publications

References 0 publications

Sphincter denervation in anorectal incontinence and rectal prolapse.

Sphincter denervation in anorectal incontinence and rectal prolapse.

A Two Stage Model of Skeletal Muscle Necrosis in Muscular Dystrophy - The Role of Fiber Branching in the Terminal Stage

Characterization and temporal development of cores in a mouse model of malignant hyperthermia

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