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Inclusion body myositis
Abstract:
The histochemical and ultrastructural study of muscle biopsies of two patients with a chronic muscle weakness and wasting showed particular changes in muscle fibers: (1) peripheral lined vacuoles, containing whorls of membranes and cytoplasmic debris; (2) collections of intranuclear and intrasarcoplasmic tubular filaments (16-18 nm in external diameter and 6.5 nm in inner diameter). These changes are characteristic of a rare muscle disorder termed inclusion body myositis; its individuality is favoured by the present study. The resemblance of the tubular filaments to myxovirus nucleocapsid has been suggested by various authors but attempts to isolate the virus were unsuccessful in several reported cases as well as in those here presented. This does not exclude a viral origin of the disease. The similarity of the tubular filaments to thick myofilaments has been invoked by others, but has not been demonstrated. At the present the nature of the abnormal filaments remains unknown.
Insights
This study details characteristic muscle fiber changes in inclusion body myositis, including peripheral vacuoles and abnormal filaments. The exact cause of these changes in this rare muscle disorder remains unknown.
Area of Science:
- Neurology
- Muscle Biology
- Pathology
Background:
- Inclusion body myositis (IBM) is a rare, progressive muscle disorder.
- Its etiology and the precise nature of observed muscle fiber abnormalities are not fully understood.
Purpose of the Study:
- To investigate the histochemical and ultrastructural characteristics of muscle fibers in patients with chronic muscle weakness and wasting.
- To contribute to the understanding of the pathological features of inclusion body myositis.
Main Methods:
- Histochemical analysis of muscle biopsies.
- Ultrastructural examination of muscle fibers using electron microscopy.
Main Results:
- Observed muscle fiber changes include peripheral vacuoles with membrane whorls and debris.
- Intranuclear and intrasarcoplasmic collections of tubular filaments (16-18 nm external diameter) were identified.
- These findings support the distinct pathological profile of inclusion body myositis.
Conclusions:
- The observed ultrastructural changes are characteristic of inclusion body myositis.
- While a viral origin has been suggested due to filament resemblance to myxovirus nucleocapsid, no virus was isolated.
- The exact nature of the abnormal filaments remains undetermined, necessitating further research.