Intermediate filaments in human myopathies.
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Animals↗
Biomedical subjects
L Edström
Publications and source records attributed to L Edström.
Genuine myotubular myopathy.
Two patients, a father and his 14-year-old son, were suffering from a facioperoneal syndrome, and muscle biopsy findings were consistent with a myotubular myopathy. The father exhibited central nuclei in most muscle fibers, but his son had typical changes exclusively in hypotrophic type I fibers. The cytochemical and ultrastructural analysis revealed a spectrum of pathological changes typical of myotubular myopathy. Energy-dispersive electron probe x-ray microanalysis was performed on 6- to 12-microns thick freeze-dried cryosections visualized in the scanning or scanning transmission mode of electron microscopy. We found a high intracellular sodium and chlorine concentration and a low potassium concentration in comparison with control muscles. These changes pointed in the direction similar to results from human fetal muscle. The changes in the intracellular elemental composition may indicate a membrane pump dysfunction, which might be caused by a partial arrest in muscle fiber maturation.
Adolescent↗
The contents of high-energy phosphates in different fibre types in skeletal muscles from rat, guinea-pig and man.
1. The contents of high-energy phosphates at rest have been measured in skeletal muscles with different fibre-type composition from rat, guinea-pig and man. All muscles studied biochemically have been characterized histochemically. 2. Fast-twitch muscles had a higher ATP/ADP ratio than slow-twitch muscles and, with the exception of the tongue in the rat, higher contents of ATP and phosphocreatine. 3. There was an inverse relationship between the content of phosphocreatine and the stainability for succinyl dehydrogenase, which is a marker enzyme for oxidative capacity. 4. The biochemical and histochemical data are discussed in relation to known morphological and functional properties of the different muscle-fibre types. It is concluded that fast-twitch fibres have a high ATP/ADP ratio favouring a fast acceleration of energy production. The content of phosphocreatine seems to be related to the glycolytic capacity but not to the contraction time. In addition to being an immediate energy source, phosphocreatine functions as a buffer against lactic acidosis.
Adenine Nucleotides↗
Five different types of centrally nucleated muscle fibres in man: elemental composition and morphological criteria. A study of myopathies, fetal tissue and muscle spindle.
Muscle biopsy material from patients with two types of benign hereditary myopathy was explored with electron probe X-ray microanalysis performed on thick cryosections observed in a scanning electron microscope equipped for the analyses. The elemental spectra thus obtained were related to the ratio between cross-sectional areas of centrally located nuclei and corresponding muscle fibres. Fetal myotubes and intrafusal muscle fibres were examined by the same methods. One of the myopathies was characterized by fibres resembling myotubes ('myotubular myopathy') and exhibited elementary spectra with i.a. higher sodium and chlorine and lower potassium signals than normally found. These spectra have a tinge of those found in fetal muscle and in extrafusal muscle fibres. The other type of myopathy had less specific morphological characteristics and exhibited different pathological changes in the muscle fibres and i.a. central nuclei in a considerable number of fibres. These nuclei were, however, smaller in relation to the cross-sectional area of the corresponding fibres than in fetal myotubes, fibres in the myotubular myopathy and in the intrafusal muscle fibres. Elemental spectra of muscle fibres in the latter myopathy conformed to the normal state. We conclude that central nuclei of muscle fibres is a pathological phenomenon which can mirror an arrest in fibre development as well as a muscle fibre degeneration. An arrest in the development is suspected in myopathic muscle fibres with large central nuclei and an elevated content of sodium chlorine in the sarcoplasm.
Adolescent↗
Sarcoplasmic bodies in distal myopathy compared with nemaline rods.
Sarcoplasmic bodies in a late onset distal myopathy and rods in nemaline myopathy have been investigated by electron probe X-ray microanalysis correlated to light microscopy. Sarcoplasmic bodies were glassy, drop-shaped structures up to 10 microns of length and easily distinguished in the scanning mode of electron microscopy performed on thick freeze-dried cryosections. They were found to be source of X-ray spectra characterized by a high sulfur peak. On semithin epoxy sections the sarcoplasmic bodies were observed in the scanning transmission mode as electron-dense structures which, according to X-ray microanalysis, exhibited a high sulphur and osmium content, possibly indicating the presence of sulphydryl groups. The nemaline rods were of 3 different types as judged by their light-microscopical appearance. They were, however, not visible in the scanning mode of electron microscopy performed on freeze-dried unstained cryosections. There were small differences in the elemental composition between different rods within the same biopsy but these were not systematically related to the differences in morphological appearance.
Adult↗
A new type of striated muscle in mammalian body: morphological, histochemical, and x-ray microanalytical observations of stapedius muscle in guinea pig.
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Adenosine Triphosphatases↗
Effects of lactic acid accumulation and ATP decrease on muscle tension and relaxation.
The present study was undertaken to evaluate the effect of lactic acid accumulation on peak tension and relaxation rate of the isometric twitch. Isolated extensor digitorum longus muscle from rat was stimulated electrically at a frequency of 2/s under anaerobic conditions. Comparison was made with muscles in which glycolysis was blocked with iodoacetic acid (IAA). Stimulation of unpoisoned muscles for 3 min decreased tension to 50% and increased relaxation time to 250% of the initial value. Lactate increased 15-fold, and muscle pH decreased from 7.10 to 6.76. Stimulation of IAA-poisoned muscles for 1 min decreased tension to 50% but did not increase the relaxation time. Stimulation of IAA-poisoned muscle resulted in a pronounced decrease (about 50%) of the ATP and total adenine nucleotide content in muscle, whereas only a small decrease (10-15%) occurred in unpoisoned muscle. The main findings in the present study were that tension decline in unpoisoned muscle is closely related to decrease in muscle pH and increase in ADP but not to ATP content per se and that slowing of relaxation rate is closely related to decrease in muscle pH but not to muscle content of ATP or creatine phosphate.
Adenosine Diphosphate↗
Glycolytic and oxidative energy metabolism and contraction characteristics of intact human muscle.
It is proposed that glycolytic rate may be measured as lactate accumulation after electrical stimulation of the quadriceps femoris muscle under anaerobic conditions. The ratio of glucose 6-phosphate to lactate is an internal monitor of the glycolytic pathway. The phosphocreatine/lactate ratio links glycolysis and the creatine kinase reaction and could be used to distinguish abnormalities in energy metabolism. The rate of resynthesis of phosphocreatine after stimulation when the circulation is restored should be measure of oxidative phosphorylation. The relaxation rate seems to be a mechanical index of the metabolic state of the muscle.
Adenosine Triphosphate↗
Histochemical and X-ray microanalytical investigations of defined organs and cells in their true position within whole-body cryosections.
Large cryosections (up to 45 x 15 cm) have been made from an entire rat or hamster or from a large human organ such as a cross section of a leg obtained from amputation operations. The quality of the sections was found to be sufficient for a histochemical and a X-ray microanalytical characterization of individual cells in the tissues of interest. When histochemical stainings were applied on sections from a human leg, different muscle groups were analysed simultaneously for pathological changes and at the same time bone tissue, nerves and blood vessels could be investigated. It was possible to study pathological changes in relation to histochemical muscle fibre type and describe the dispersion of changes within a certain muscle. Analytical scanning electron microscopy (X-ray microanalysis) was useful for the description of the elemental composition of different organs on longitudinal sections of small animals and of different muscle fibres in the leg cross sections. The X-ray emission could be related to histochemical muscle fibre type and other parameters such as the degree of fibre atrophy.
Animals↗
The distribution of intermediate filament protein (skeletin) in normal and diseased human skeletal muscle--an immunohistochemical and electron-microscopic study.
The presence of intermediate filaments in various mature and immature eukaryotic cells is well documented. By using antibodies against the intermediate (skeletin) filaments of cow heart Purkinje fibres, we have in the present work analyzed the distribution of skeletin in normal and diseased skeletal muscle fibres. Antiskeletin proved to be a useful tool for the identification of regenerating fibres in Duchenne muscular dystrophy. In mature muscle fibres with well-preserved myofibrils, skeletin had an intermyofibrillar localization at the Z-disk level where intermediate filaments were demonstrated. The presence of skeletin was also demonstrated around the rods of muscle fibres in nemaline myopathy biopsies, but the rods themselves did not show any cross-reactivity. This report exemplifies the usefulness of antibodies in muscle pathology.
Adolescent↗
A new type of hereditary distal myopathy with characteristic sarcoplasmic bodies and intermediate (skeletin) filaments.
A family with a hitherto unrecognized type of distal myopathy is described. The disorder appears to be of late onset and to be inherited through a dominant autosome. It has a more malignant course than the distal myopathies described earlier, from which it can be differentiated clinically by an early involvement of thenar muscles and hand flexors. The key to the correct diagnosis is provided by the morphological and immunohistological investigation of muscle biopsies, which show typical sarcoplasmic bodies and an abundance of intermediate-sized (skeletin) filaments.
Adenosine Triphosphatases↗
Sulphur and phosphorus content in relation to fibre composition and atrophy of skeletal muscle in patients with Parkinson's disease.
Seventeen patients with Parkinson's disease have been compared with 8 normal individuals by biopsy of either the biceps brachii or quadriceps femoris muscles. All biopsies were investigated by enzyme histochemistry. With 13 patients, as well as all controls, scanning electron microscopy with X-ray microanalysis was employed on cryo-sections adjacent to those prepared for light microscopy. Thus, the elemental composition of single muscle fibres was obtained and could be related to histochemical fibre types. Fibre type analysis on the diseased material, based on differential stainability for alkali- and acid-stable ATPase, showed a normal type I and type IIA fibre frequency. A mild type IIB dominance at the expense of type IIA fibres was regarded as a significant deviation from normal. A slight to moderate muscle atrophy affected type IIB fibres almost exclusively. Normal content of sulphur and phosphorus was detected in type I and type IIA Fibres but a lowered sulphur content was obvious in type IIB fibres, especially in the atrophic ones, which also exhibited an increase in phosphorus content. The shift in fibre composition from IIA to IIB, the type IIB fibre atrophy and the change in sulphur and phosphorus content of type IIB fibres are interpreted as signs of a disuse which preferentially affects fast twitch type IIB motor units. These presumably have the highest threshold for activation under pathological conditions characterized by increased muscular tone and difficulties in the performance of rapid and strong voluntary movements.
Adenosine Triphosphatases↗
[Muscle biopsy examination in neuropathies].
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Biopsy↗
[Can muscle fiber composition be changed?-Histochemical viewpoints on changes after training and central nervous system motor disorders].
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Child↗
Electron probe X-ray microanalysis of human skeletal muscle involved in rheumatoid arthritis.
Electron probe X-ray microanalysis in the scanning microscope was used to determine the elemental composition of muscle fibres from patients with rheumatoid arthritis (RA). Quantitative data concerning phosphorus, sulphur, chlorine and potassium were correlated to the fibre type by a routine method based on serial cryosectioning and histochemical staining of adjacent sections. Significantly lowered sulphur values were found in type II A and II B muscle fibres of RA patients as compared to those of healthy controls. Traces of gold were detected in muscles of two patients treated with gold salts. The basis and mechanism for the decreased sulphur content in RA muscles are so far unknown, but may depend on the decreased amount of sulphur-rich potein(s).
Adult↗
Electron probe X-ray microanalysis of human muscle biopsies.
The elemental composition of human muscle fibres have been determined by electron probe microanalysis. In order to distinguish between different types of fibres, two approaches were used. In one approach individual fibres were isolated, portions of them used for a typing by histochemical methods and the main part used for X-ray microanalysis. In the other approach the muscle biopsy was serial-sectioned, some sections used for a histochemical typing and the others (16 micrometer thick cryosections) used for X-ray microanalysis in th eelectron microscopy. The comparison of the ratios between P, S and K in Study No. 1 and 2 indicates different concentrations of sulphur in the subsarcolemmal zone and in the interior of the fibre. Both routes give information on all elements (except the ten lightest ones) contained in the fibres or in sections of them, provided the concentration is high enough. In order to obtain quantitative data, expressed as mmol/kgw, the spectra of the specimens were compared to those of standards of known composition and the data subjected to a so called ZAF-correction (corrections for the atomic number effect, absorption of X-rays in the specimen and secondary fluorescence). Quantitative data concerning phosphorus, sulphur, chlorine and potassium were obtained in Study No. 2. A significantly higher sulphur concentration was found in type IIA muscle fibres as compared to those of type I.
Chlorine↗
Changes in muscle fibre size and physical performance in patients with rheumatoid arthritis after short-term physical training.
Ten patients with rheumatoid arthritis of moderate severity were given 6 weeks' intense physical training. During the investigation period the patients improved their physical performance capacity as well as their rate of perceived exertion. There was an increase in the muscle fibre size, of type I and type II, most pronounced in the latter fibre group. No 'flare-up' of the arthritis could be seen during the training period. Comments are made as to which patients might benefit by a short-term physical training.
Adult↗
Changes in muscle fibre size and physical performance in patients with rheumatoid arthritis after 7 months physical training.
Ten patients with rheumatoid arthritis of moderate severity were given 7 months' physical training. During the investigation period the patiens improved their physical performance capacity as well as they lowered their rate of perceived exertion during submaximum exercise. There was a small increase in muscle fibre size and a correlation was found between muscle strength and type II fibre size. Clinical examination and X-ray studies did not reveal any further joint destruction during the investigation period.
Adult↗