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Biomedical subjects

L Edström

Publications and source records attributed to L Edström.

At least 19 recordsLinked to original sources
PubMed1994

Distribution of muscle degeneration in Welander distal myopathy--a magnetic resonance imaging and muscle biopsy study.

Seven patients with Welander distal myopathy were subjected to magnetic resonance imaging (MRI) of the lower extremity, and muscle biopsies of the tibialis anterior, soleus and vastus lateralis muscles. MRI revealed abnormalities in both the anterior and posterior compartments of the lower leg in three of the patients, and in only the posterior compartment in the rest of the patients. No MRI abnormalities were found in either the proximal muscles of the leg or in the peroneal or posterior tibial muscle groups. Affected muscles had T1- and T2-values indicating a replacement of muscle fibres with fat tissue. Muscle biopsies showed pathological changes varying from slight to severe in tibialis anterior and soleus muscles in all patients. No muscle fibre abnormalities were seen in the vastus lateralis muscle in any of the patients. In accordance with earlier reports from patients with Welander distal myopathy, there was muscle degeneration of tibialis anterior muscles corresponding to the weakness of dorsal extension of the feet, but also degeneration in the muscles of the posterior compartment. The patients did not, however, show any clinical signs of weakness related to posterior muscle groups. There is no evidence of involvement of proximal muscles of the leg clinically, with MRI or in muscle biopsies.

Adult↗
PubMed1994

Myofibers from Duchenne/Becker muscular dystrophy and myositis express the intermediate filament nestin.

The intermediate filament nestin is transiently expressed in developing skeletal muscle. In the present investigation, we analyzed by immunohistochemistry the presence of nestin, as well as vimentin and desmin, in skeletal muscle affected by two diseases characterized by various degrees of necrosis and muscle regeneration: Duchenne/Becker muscular dystrophy and myositis. Nestin-positive areas were found in all analyzed muscle biopsies of both diseases. The same areas were, in most cases, also positive for vimentin and stained more intensely for desmin than surrounding myofibers. Only nestin was found specifically in myopathic muscle fibers; vimentin was in addition present in muscle fibroblasts and desmin in all myofibers. The areas staining positive for nestin were typically basophilic, small-diameter myofibers, often with centrally located nuclei. With the interesting exception of a 73-year-old healthy control with abundant ring fibers, nestin was not detected in the muscle of healthy controls. The intracellular distribution of nestin in the myopathic muscle fibers, as well as in the ring fibers, was confined to the vicinity of Z-bands. The presence of nestin protein in myopathic regenerating areas and in ring fibers correlated more closely to the presence of desmin than to vimentin immunoreactivity. Our results suggest that nestin is specifically expressed in newly formed muscle fibers also during regeneration, and that nestin may serve as a useful marker of regenerating muscle fibers in pathological conditions.

Adolescent↗
PubMed1994

Distribution of sodium, magnesium, chlorine, calcium, potassium, phosphorus and sulphur in Z-, I- and A-bands in mammalian striated muscle.

The regularity of the striation of skeletal muscle offers a unique possibility to analyze different bands of the sarcomere in longitudinally cut semithin cryosections. The aim of the present study was to investigate the elemental content of the Z-, I- and A-bands within the sarcomere which may be related to the affinity of an element to different contractile elements and the water content in different bands. The highest potassium levels were found in the Z-band (802 mmol/kg dry weight (d.w.)) as compared to the I-band (697 mmol/kg d.w.) and the A-band (731 mmol/kg d.w.). The difference between A-band and Z-band, but not between I-band and A-band, was significant. The highest phosphorus values were detected in the Z- and I- bands and the lowest within the A-bands (632, 615 and 540 mmol/kg d.w. respectively). No significant differences were found in the concentrations of Na, S, or Cl. Ca was significantly lower in the I-band as compared to A- and Z-band. The Mg concentration in the I- and A-band was significantly higher than in the Z-band. By means of computerized densitometry, relative densities (proportional to the dry mass content) of the Z-, I- and A-band were calculated (23.9, 11.6, and 19.2, respectively). The mean value of dry mass over several sarcomeres varied between 19.5-22.5 which corresponds well with dry weight mass concentrations obtained by traditional methods. The values for dry mass content allowed recalculation of the elemental concentrations as mmol/kg wet weight.

Animals↗
PubMed1993

Muscle fibre degeneration in distal myopathy (Welander)--ultrastructure related to immunohistochemical observations on cytoskeletal proteins and Leu-19 antigen.

In seven patients with long-standing and six patients with early symptoms of Welander distal myopathy (WDM), monoclonal antibodies directed against such cytoskeletal proteins as dystrophin, spectrin and desmin and against Leu-19, a myoblast and satellite cell related antigen, were applied to muscle biopsies from the anterior tibial and soleus muscles. In addition, ultrastructural studies were carried out on biopsies from the soleus muscle. In muscle fibres from patients with early symptoms there was normal immunostaining for dystrophin, spectrin, desmin and Leu-19. In the patients with long-standing symptoms, there was also a normal expression of dystrophin, and a normal staining for spectrin and desmin was found in normal sized muscle fibres. Occasionally normal sized muscle fibres showed staining for Leu-19. Increased staining for spectrin and desmin and a strong Leu-19 staining was seen in normal sized muscle fibres with rimmed vacuoles and in atrophic fibres. Increased staining for spectrin, desmin and Leu-19 has been described in denervated muscle fibres and, thus, the present findings may support earlier findings of a neurogenic component in Welander distal myopathy. In the soleus muscle, ultrastructural muscle fibre abnormalities conformed to those in the anterior tibial muscle. Many rimmed vacuoles were observed which corresponded, at the ultrastructural level, to autophagic vacuoles. Intranuclear and cytoplasmic filamentous inclusions of the same shape and diameter as in inclusion body myositis were observed.

Adult↗
PubMed1993

Improved electrophoretic method for the analysis of dystrophin in human muscle.

A new simplified electrophoretic and Western blotting technique for the study of dystrophin in muscle biopsy material is presented and compared with immune histochemistry. The method is based on separation of dystrophin in a linear SDS-PAGE pore gradient of 4-8% acrylamide in ultra-thin, horizontal gels on plastic film support followed by horizontal electrotransfer for Western blotting. The advantages of this procedure are short separation and transfer times at high field strength, high resolution, short staining procedures and small requirements of chemicals. Samples from the same gel can be cut and examined with different antibodies. Final results are obtained in one day. Examination of patients with various types of muscular dystrophies verified the essential absence of dystrophin in DMD patients, and showed considerable dystrophin heterogeneity in patients with BMD. A girl with severe symptoms of dystrophy revealed unexpected dystrophin abnormalities. The results also indicated that SDS-PAGE with Western blotting and immune histochemistry are complementary, diagnostic, and research instruments, and that the reactivity of commercial antibodies may differ in these two techniques.

Adult↗
PubMed1993

Larger expansions of the CTG repeat in muscle compared to lymphocytes from patients with myotonic dystrophy.

The discovery that there is an expansion of a CTG repeat underlying myotonic dystrophy has led to new approaches in diagnosis and genetic counselling for this disorder. The size of the expansion correlates to a reasonable degree with the clinical symptoms within a given family. We report comparisons of the length of the expansion seen in lymphocytes and muscle samples from eight patients. In all cases the length of the expansion seen in DNA isolated from muscle was larger than that seen in lymphocytes from the same patient. There was no progression of the expansion over a period of 10-15 years in muscle samples from two of these patients even though there had been significant progression of the severity of symptoms during that time.

Adult↗
PubMed1993

Paramyotonia congenita (Eulenburg): clinical, neurophysiological and muscle biopsy observations in a Swedish family.

A Swedish family with Paramyotonia congenita (Eulenburg) (PMC) is presented. Clinical neurological examination, neurophysiological examination (n = 5) and muscle biopsy (n = 4) were performed. Different clinical features were found in various combinations in the individual family members. The clinical symptoms were: (1) cold-induced myotonia, (2) attacks of weakness, (3) persistent weakness and (4) no symptoms but other signs of muscle affection. In the patients with myotonia, the neurophysiological examination showed spontaneous myotonic discharges which were frequent at room temperature but disappeared after cooling. Furthermore, the amplitude of M. abductor digiti minimi compound action potential, during supramaximal ulnar nerve stimulation, decreased significantly after cooling. In the patients with persistent weakness there were no spontaneous myotonic discharges, but myopathic abnormalities were found in proximal muscle. In the patients with myotonia as well as in the patients with manifest muscle weakness, muscle biopsy showed a variation of muscle fibre diameters, centrally located nuclei, occasional atrophic fibers and an atrophy of type IIB muscle fibres. These findings are unspecific but have been described in PMC patients in earlier studies. An ancestor to the family, who had myotonia, lived in the same town and at the same time as Albert Eulenburg, which may suggest that this family is a part of the originally described family (1).

Action Potentials↗
PubMed1993

Prior poliomyelitis: an immunohistochemical study of cytoskeletal proteins and a marker for muscle fibre regeneration in relation to usage of remaining motor units.

Patients with prior poliomyelitis with paresis and excessive use (n = 8) and low use (n = 6) of residual anterior tibial motor units (MUs) during walking were subjected to muscle biopsy of the anterior tibial muscle (TA). Antibodies directed against cytoskeletal proteins, spectrin and desmin, and against Leu-19, a myoblast and satellite cell related antigen, were applied. In the patients with excessive use of residual MUs there was an almost total predominance of hypertrophic type I fibres. In the hypertrophic fibres, staining for spectrin and desmin was normal while staining for Leu-19 was seen in a few fibres. Scattered atrophic fibres seen in the patients with excessive use showed staining for spectrin, desmin and Leu-19. In the patients with low use of residual MUs there were extensive pathological muscle fibre changes. Increased staining for spectrin, desmin and Leu-19 was found in most of the atrophic fibres. The predominance of type I fibres in the patients with excessive use of residual MUs is suggested to be due to muscle fibre transformation. The normal staining pattern for spectrin and desmin in the hypertrophic fibres indicates a normal cytoskeletal structure which might suggest that the adaptive muscle fibre changes are adequate to meet the increased demand. The increased staining for spectrin, desmin and Leu-19 in the atrophic fibres might indicate an ongoing denervation process which earlier has been suggested as an important factor for the development of postpolio progressive muscular atrophy.

Adult↗
PubMed1992

Neurogenic effects on the palatopharyngeal muscle in patients with obstructive sleep apnoea: a muscle biopsy study.

Muscle biopsies from the palatopharyngeal muscle of eight patients with obstructive sleep apnoea were performed during uvulopalatopharyngoplasty. Control biopsies were performed during tonsillectomy in seven control patients with no history of symptoms suggesting obstructive sleep apnoea. The diagnosis was based on the patient's history and a whole night recording of arterial oxygen saturation and respiration movements. The mean number of oxygen desaturations > or = 4% per sleeping hour was 39 (range 7-80) in patients with obstructive sleep apnoea. In the control patients the occurrence of muscle fibre type and size relation between type I and type II fibres were comparable to what is found in the quadriceps femoris muscle, but the mean size of the fibres was < 25% of what is found in limb muscles. All biopsies from patients with obstructive sleep apnoea showed abnormalities. Atrophy with a fascicular distribution, increased number of angulated atrophic fibres, a twin or multiple peak distribution of the fibre size spectra, and an abnormal distribution of fibre types in many muscle fascicles corresponding to "type grouping" all points to a neurogenic alteration. This neurogenic lesion may be a primary phenomenon or secondary to the trauma of repetitive and prolonged stretching of the pharyngeal structures during apnoeas. A disturbance of the function of the dilating muscles of the upper airway may be important in causing the abnormal airway collapse seen in obstructive sleep apnoea.

Adult↗
PubMed1992

Motoneuron activity and muscle fibre type composition in hemiparesis.

The firing of single motor units (MUs) in musculus tibialis anterior (TA) was studied during maximal voluntary effort and maximal speed of walking in 10 patients with severe chronic hemiparesis and the findings compared to normal data. As shown in a previous study, the paralysed TA exhibited an increase in proportion of type 2 fibres as compared with normal muscle. Thus, 57% of the muscle fibres were type 1 and 43% type 2, while the normal percentages were 80% and 20% respectively. The present findings indicate that in the paralysed muscles a little less than half of the fibres, i.e. roughly the equivalent of the type 2 population, was not tonically active either during sustained voluntary contraction or during locomotion. Normally high threshold MUs reached high rates during both modes of activation. The findings paralysed muscles also indicate that a little more than half of the fibres, i.e. roughly the equivalent of the type 1 population, could be brought into tonic firing during voluntary contraction as well as during walking. Their maximal firing rate was, however, no more than two thirds of that of normal low threshold MUs.

Aged↗
PubMed1991

Intranuclear and cytoplasmic filamentous inclusions in distal myopathy (Welander).

Ultrastructural examination of anterior tibial muscle from four patients with late-onset autosomal dominant distal myopathy of Welander-type revealed intrasarcoplasmic filamentous inclusions in association with rimmed vacuoles. In one of the patients, identical intranuclear filamentous inclusions were also found. These filamentous inclusions are similar to those described in inclusion body myositis (IBM). They have also been observed in hereditary neuromuscular disorders including autosomal recessive distal myopathy. Thus, the filamentous inclusions occur in different neuromuscular conditions with different etiologies. These findings further raise the question of the specificity of the filamentous inclusions in IBM.

Adult↗
PubMed1991

Disuse of anterior tibial muscle during locomotion and increased proportion of type II fibres in hemiplegia.

The tibialis anterior (TA) is a muscle activated mainly during walking. Its use during the step cycle was studied in 10 patients (55.8 +/- 8.8 years) with chronic hemiplegia (duration 3-18 years) and related to the muscle fibre composition, size and expression of isoforms of myosin heavy chains (MHCs). In the average step cycle the integrated surface EMG of the paralysed TA did in the majority of the hemiplegic patients not exceed 10% of that recorded during maximal contraction of the normal leg. The type I fibre percentage in the paralysed TA subject was 57.4% as compared with 79.4% in normal muscles (P less than 0.05). The range of axonal conduction velocities in the peroneal nerve did not differ in paralysed and non-paralysed leg, suggesting that there was no selective loss of one class of motoneurons. The type II fibres consisted of IIA (66%) and IIB (31%), in contrast to the normal TA muscle where less than 1% of the muscle fibres are of type IIB. The incidence of fibres in the biopsies with both slow and fast MHCs had a mean value of 3.5% (range 0.7-9%). The type I and type II muscle fibres had normal sizes with cross-sectional area 4511 +/- 962 microns 2 and 6181 +/- 1062 microns 2. No selective type II atrophy was seen. Occasional hypertrophic type I and II fibres were seen in 4 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Inclusion body myositis and Welander distal myopathy: a clinical, neurophysiological and morphological comparison.

Five patients with inclusion body myositis (IBM), an acquired inflammatory myopathy, and five patients with Welander hereditary distal myopathy (WDM) were compared clinically and with neurophysiological and morphological techniques. Both diseases have a late insidious onset, but the course of IBM is more severe. IBM mainly affects proximal muscles in the lower extremities, while distal muscle groups are involved in both upper and lower extremities. In WDM there is always a strict distal muscle involvement. The neurophysiological characteristics of the two conditions include both myopathic and neurogenic components. In both diseases there were rimmed vacuoles in muscle fibres and at the ultrastructural level cytoplasmic 15-18 nm filamentous inclusions. Although the histopathology of muscle in IBM and WDM has some common features, inflammatory infiltrates were never found in WDM. Such infiltrates seem to be an important clue to the correct diagnosis of IBM.

Aged↗
PubMed1991

Effects of age on physiological, immunohistochemical and biochemical properties of fast-twitch single motor units in the rat.

1. Physiological, enzyme-histochemical, biochemical and morphometrical properties of fast-twitch single motor units were compared between young (3-6 months) and old rats (20-24 months) using the glycogen depletion technique. Monoclonal antibodies (mAbs) were used to identify the myosin heavy chain (MHC) composition in the muscle fibres of the motor unit (motor unit fibres) in order to facilitate correlative physiological, histochemical, biochemical and morphometrical studies. 2. Earlier observations on effects of age on contractile properties of fast-twitch motor units were confirmed and extended. That is, the duration of the isometric twitch, and the twitch and tetanus forces, were increased. Further, motor unit fibres were rearranged, occupying a larger territory and displaying an increased innervation ratio in old age, indicating a denervation-reinnervation process. 3. Motor units with muscle fibres expressing the novel IIX myosin heavy chain (MHC) were observed in both young and old animals, and they constituted the predominant motor unity type identified in the old animals. In contrast to the type IIX MHC motor units in the young animals, the type IIX MHC units in old age often contained muscle fibres which expressed either the type IIA or type IIB MHC, although type IIX MHC fibres were in the majority (so called 'IIX' MHC motor units), but motor units containing all these three fibre types were never observed. There were also single fibres co-expressing IIX and IIB MHCs in old age. 4. In the young animals the IIX MHC motor units had a higher (P less than 0.001) resistance to fatigue (fatigue ratio 0.45 +/- 0.11) than the type IIB MHC units (0.03 +/- 0.05), a succinate dehydrogenase (SDH) activity (0.62 +/- .007) intermediate (P less than 0.001) between those of type IIA muscle fibres classified according to myofibrillar ATPase activity after acid pre-incubation, i.e. type IIA ATPase, (0.84 +/- 0.13) and type IIB MHC motor unit fibres (0.20 +/- 0.04), and cross-sectional fibre areas (1650 +/- 320 microns 2) which were similar to those of type IIA ATPase muscle fibres (1460 +/- 150 microns 2) but smaller (P less than 0.001) than type IIB MHC motor unit fibres (4650 +/- 1180 microns 2).(ABSTRACT TRUNCATED AT 400 WORDS)

Adenosine Triphosphatases↗