Joan M. Round

Fibre areas and histochemical fibre types in the quadriceps muscle of paraplegic subjects

With the advent of functional electrical stimulation (FES) there is the possibility of paraplegic patients regaining some degree of locomotor activity. It is of interest to document the changes in composition histochemistry and size of muscle fibres in such patients both before and after such therapy. We have examined biopsy specimens from quadriceps muscles obtained from 7 male patients, age range 24-47 years, who had been paraplegic for times ranging from 11 months to 9 years and we report the histochemical appearance of the muscle the fibre type composition and the mean fibre areas. In 5 of the 7 subjects there was a marked or complete predominance of fibres which stained as type 2 with the ATPase reaction at pH 9.4. At acid pH these fibres were seen to be predominantly 2B (fast fatigable). The 2 subjects who had been paralysed for the shortest periods had proportions of type 1 fibres which were relatively well preserved. The mean fibre areas of type 2 fibres were below the normal range (2500-7500 microns 2) in every case as were the type 1 fibres in the 4 patients in which these were still present. There was no relationship between the length of time the patient had been paralysed and the mean fibre areas which suggests that atrophy occurs fairly quickly following loss of voluntary control and precedes the loss of type 1 characteristics. Our findings provide an explanation for the rapid onset of fatigue in paraplegic patients taking part in FES programmes since muscles deficient in type 1 fibres will be unable to maintain force for any length of time.

CELLULAR INFILTRATES IN HUMAN SKELETAL-MUSCLE - EXERCISE INDUCED DAMAGE AS A MODEL FOR INFLAMMATORY MUSCLE DISEASE

The type and distribution of mononuclear cell infiltrates in muscle biopsies taken from 9 subjects at differing times after exercise in which the muscle is stretched (eccentric exercise) has been characterised. The appearances are compared to those seen in muscle from patients with inflammatory muscle disease. After exercise infiltrating cells were seen in perivascular, perimysial and endomysial regions, the extent being greater in the later biopsies (9-14 days). The predominant cell type was the macrophage (46-100% of all infiltrating cells), the remainder were T lymphocytes with a predominance of the CD4 positive helper/inducer subset. Approximately one third of the T cells expressed DA2 (class 2) antigen indicating that they were activated. Very few B lymphocytes and no Leu7 positive cells were seen. There was evidence of class 1 expression on some of the damaged muscle fibres. The appearance of the experimentally damaged muscle in normal subjects was very similar to untreated polymyositis suggesting that a proportion of the infiltrating cells seen in this disease may be present as part of a natural response to damage rather than being its cause.

Size and composition of the calf and quadriceps muscles in Duchenne muscular dystrophy

Calf and quadriceps muscle size and composition have been examined in 5 control subjects and 12 boys (aged 7-18 years) with Duchenne muscular dystrophy using computed tomography (CT) and quantitative histochemistry of needle biopsy samples of muscle. In assessing the size of leg muscles it was found that in control subjects the muscle cross-sectional area was related to the cross-sectional area of the femur. The calf muscles in the patients were enlarged both relative to the quadriceps and absolutely when related to the cross-sectional area of the femur used as an index of stature. The enlargement of the calf was the result of accumulations of fat and connective tissue in the presence of relatively normal (compared to femur size) amounts of muscle tissue. Although hypertrophied muscle fibres were a feature of the biopsy samples in the calf the extent of this was insufficient to contribute appreciably to the total muscle enlargement.

Skeletal muscle in health and disease : a textbook of muscle physiology

Part 1 Skeletal muscle structure: muscle fibres - size and number muscle organization the contractile proteins structural proteins sarcoplasmic reticulum T-tubular system the EM appearance of different fibre types other structures. Part 2 The mechanism of force generation: methods for measuring contractile properties length-tension relationship of skeletal muscle the nature of the interaction between thick and thin filaments force velocity characteristics biochemistry of force generation. Part 3 Innervation and electrical activity: connections between nerve and muscle the motor unit the neuromuscular junction excitation-contraction coupling calcium transients removal of calcium from the interior of a muscle fibre. Part 4 Histochemistry, contractile properties and motor control: histochemistry contractile properties the relationship between histochemistry and contractile properties the control of fibre type expression motor unit recruitment sensory receptors in skeletal muscle reflex activity coordination of muscular contractions. Part 5 Growth, development and ageing of muscle: embryonic origins and foetal development size of adult muscle endocrine influences on growth and development strength and muscle mass body proportions (somatotypes) the use of anabolic drugs in sport ageing and muscle function. Part 6 Training for power: power output and performance specificity of the training response changes in muscle strength and size during training the stimulus for increase in strength. Part 7 Adaptations for endurance exercise: central drive peripheral fatigue energy supply energy reserves and rates of utilization strategies for improving performance in endurance exercise cardiovascular or peripheral limitations to exercise temperature regulation and dehydration. Part 8 Fatigue: the definition of fatigue central factors the neuromuscular junction peripheral factors motor unit firing frequency fatigue during dynamic or prolonged exercise. Part 9 Muscle damage: physical trauma metabolic depletion damage due to eccentric contractions muscle regeneration. Part 10 Muscular pain: sensory nerves muscle pain during activity pain developing after exercise the effect of training on muscle pain muscle cramp myalgic pain. Part 11 Muscle diseases: atrophic myopathies inflammatory myopathies dystrophies congenital myopathies neuropathies myasthenia gravis neuromuscular changes in human immunodeficiency virus (HIV) infection post viral fatigue syndrome (myalgic encaphalomyelitis) disorders of energy metabolism myotonic syndromes the periodic paralyses malignant hyperpyrexia.

The anatomy and fibre type composition of the human adductor pollicis in relation to its contractile properties

We have examined the anatomy and fibre type composition of the human adductor pollicis in muscles taken post mortem. Histochemical staining of muscle fibres showed that type I fibres predominated in all cases with a mean occurrence of 80%. This composition is similar to that of the soleus muscle and unlike that of the quadriceps which has approximately equal proportions of the two fibre types. Comparing the contractile characteristics, however, the adductor pollicis has similar properties to the quadriceps and both are quite distinct from those of the slowly contracting soleus muscle. The lack of correlation between fibre composition, as revealed by histochemical staining, and contractile properties in these muscles must mean that fibres of the same type from different muscles do not necessarily have the same contractile speed. The results also suggest that the type I fibres of the human adductor pollicis are faster than those of both the soleus and quadriceps muscles.

Changes in Skeletal Muscle after Discontinuation of Growth Hormone Treatment in Young Adults with Hypopituitarism

Rutherford, O.M., Jones, D.A., Round, J.M. and Preece, M. (Department of Medicine, Rayne Institute, University College and Middlesex School of Medicine; and the Department of Growth and Development, Institute of Child Health, Great Ormond Street, London, UK). Changes in skeletal muscle after discontinuation of growth hormone treatment in young adults with hypopituitarism. Acta Paediatr Scand [Suppl] 356: 61, 1989.

Muscle disease, HIV and zidovudine: the spectrum of muscle disease in HIV-infected individuals treated with zidovudine.

Eleven patients with AIDS or AIDS-related complex who developed muscle-related symptoms whilst taking zidovudine were investigated. The clinical details of a further ten patients who did not undergo muscle biopsy are also outlined. The clinical features, quantitative muscle strength testing, electromyographic findings, serial creatine kinase levels, muscle biopsy appearance on light microscopy and the effects of zidovudine withdrawal and rechallenge are described. The spectrum of muscle disease encountered included four cases of frank myopathy diagnosed using clinical, electrophysiological and histological criteria, four patients with mild weakness and myalgia in whom muscle biopsies were normal, three patients with myalgia only and a mild increase in the interstitial cell infiltrate shown by biopsy. The patients presenting with myopathy showed no improvement on withdrawal of zidovudine but responded to immuno-suppressive therapy with steroids and, in one case, thalidomide prescribed incidentally. At present, it is not yet possible to clinically define a specific zidovudine-induced myopathy that is distinct from the other effects of HIV infection on muscle structure and function. Our experience suggests that zidovudine may be implicated as a myotoxin in some patients, particularly those with myalgia and mild weakness. In those patients with severe weakness, and with biopsy findings of necrosis and inflammation, the drug effects may be difficult to separate from the primary effects of HIV.

Growth Hormone Deficiency in Adults ‐ an Indication for Therapy?

Case studies are presented for two patients, one with isolated hGH deficiency and one with multiple hormone deficiencies. The patients were studied 3 months before, and 3 and 9 months after discontinuing hGH therapy, at 19 and 18 years of age, respectively. Strength in the quadriceps femoris, cross‐sectional area of the quadriceps muscles and cross‐sectional muscle fibre area were measured. In the patient with multiple hormone deficiencies, clear decreases in all three parameters were evident after discontinuing hGH treatment. There were no significant changes in the other patient. Reasons for these differences are discussed.

Muscle Strength in Girls with Congenital Adrenal Hyperplasia

ABSTRACT. To assess whether exposure to excessive adrenal androgens increases muscle strength in girls with congenital adrenal hyperplasia, eighteen girls with 21 hydroxylase type congenital adrenal hyperplasia (CAH), aged 4.3–12.1 years were studied and compared with 78 healthy control girls aged 4–16 years. Maximum voluntary isometric strength was measured using a muscle testing chair, and the highest value from at least three attempts with each leg was recorded. Height and weight were also measured in the patients and controls. When compared with normal girls of similar age, some of the girls with CAH seemed unusually strong, but this difference was less marked when the CAH girls were compared with controls of similar weights. However, our data suggest that girls diagnosed later in childhood may have unusual muscle strength.

Human Metabolic Study of Milk Simultaneously Fortified with Zinc, Iron and Copper

Milk is a rich source of calcium and1 an attractive vehicle for zinc, iron and copper fortification as it is widely consumed2,3. In its pulverised form milk could help the nutritional status of large segments of the population. The aim of this balance study is to enquire into the metabolism of milk simultaneously fortified with zinc, iron and copper in man.