Lars Edström

Selective changes in the sizes of red and white muscle fibres in upper motor lesions and Parkinsonism

Abstract Muscle biopsy material from patients with upper motor neurone lesions (10 cases) and Parkinsonism (9 cases) has been studied by histochemical techniques. The muscle fibres were divided into two groups on the basic of staining reactions for myofibrillar ATPase, and the two groups were considered separately in the measurement of the cross-sectional areas of the muscle fibres. The following changes in size have been observed in the two conditions. Fibres with a high concentration of myofibrillar ATPase (white fibres) as demonstrated histochemically showed atrophy of differing degree. Fibres with a low concentration (red fibres) usually remained unchanged and sometimes even showed hypertrophy. These changes appeared to be related respectively to the reduction of muscular power and the increase of tone. It is suggested that this phenomenon is the effect of selective disuse of high-threshold phasic motor units owing to paresis and increased usage of low threshold tonic units owing to spasticity and rigidity. In 2 cases with upper motor neurone lesions certain red fibres showed pronounced cytological changes in the form of a central decrease in the activity of oxidative enzymes, resembling “targetoid” fibres. In 1 of the cases there were also three-zone fibres similar to “target fibres”. In Parkinsonism small, scattered zones in which there was a loss of the staining reaction for oxidative enzymes were encountered in a large number of red fibres. In both the cases with “targetoid-like” fibres the atrophied white fibres showed a reduction in the density of staining for phosphorylase and PAS.

HISTOCHEMICAL TYPES AND SIZES OF FIBRES IN NORMAL HUMAN MUSCLES

I>uring the past ten years, great interest has been focused on muscle histochcmistry. Much information has been presented on muscle fibre types in different animal muscles (Nachmias & Padykula 1958, Dubowitz & Pearse 1960, Stein & Padykula, 1962, Ogata & Mori 1964, Ronianul 1964, Henneinan & Olson 1965, Bocek & Beatty 1966, Nystriiiiz 1968). Information has also been obtained from normal muscle in man, both in adults ( W a c h s f e i n & Meisel 1955, Beckett & Bourne 1958, Dubowitz & Pearse 1960, 1961, Engel, 1962, 1965, Ogata & Mori 1964) and during development (Dubowitz 1963, 1965, 1966, Fenichel 1963, 1966). Several papers have dealt with neuromuscular disorders, see review by Engel & Brooke 1966. Bajusz (1964) observed in mice and Engel, Brooke & Nelson (1966) in the cat that muscle atrophy caused by denervation is due almost entirely to a while muscle fibre (type 11, A fibre) atrophy. Conversely, tenotomy caused the red fibres (type I, C fibres) to atrophy (Enge l et al. 1966). Recent observations by E d s f r 6 m ( 1968) imply that motility disturbances following central nervous lesions or joint lesions produce different effects on red and white fibres in man. To quantitate pathological changes, howcver, and especially the dcgree of atrophy or hypertrophy of different histochemical fibre types, there is a need for more information about the normal state. The present study was undertaken to obtain such information.

Selective atrophy of red muscle fibres in the quadriceps in long-standing knee-joint dysfunction: Injuries to the anterior cruciate ligament☆

Abstract A histochemical study has been made of muscle biopsy material from 11 patients with injuries of the anterior cruciate ligament of the knee-joint. The material consists of 1 case of acute injury and 10 with long-standing injury. All biopsies were made from the vastus medialis. The muscle fibres were divided into two groups on the basis of staining reactions for myofibrillar ATPase and the groups were measured separately when assessing muscle fibre areas in cross section. Eight of the cases, with clinical evidence of muscular atrophy, showed marked differences in size between the red and white muscle fibres. These differences were expressed as a quotient between the mean value for cross-sectional area of the white and red fibres in each particular case. In these cases the quotients were 1.48-1.97. The red fibres exhibited a comparatively low mean value, which was interpreted as being due to selective atrophy of this group of fibres. The patient with an acute injury and two with more long-standing injury, all of whom lacked clinical signs of atrophy of the quadriceps, showed roughly equally-sized red and white fibres with quotients of 0.90-1.12. These size relationships conformed to those obtained in the normal quadriceps muscle. The results are discussed in relation to earlier and similar studies of muscle biopsy material obtained from patients with upper motor neurone lesions and Parkinsonism.

Electron probe X-ray microanalysis of human muscle biopsies

SummaryThe 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 μm thick cryosections) used for X-ray microanalysis in the electron microscope.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/kgdw, 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.

Electron Probe X-ray Microanalysis of Human Skeletal Muscle Involved in Rheumatoid Arthritis

SummaryElectron probe X-ray microanalysis in the scanning microscope was used to determine the elemental composition of muscle fibes 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 protein(s).