Plasma levels of 25-hydroxycholecalciferol (25-HCC) were measured by a specific competitive protein-binding assay. Mean levels in both normal London adults and adolescent schoolchildren were 16 ng/ml and the mean level in a group of epileptic patients on high-dosage anticonvulsant therapy was 5 ng/ml, (difference from normals P < 0.001). Two further epileptic patients, with well-marked anticonvulsant osteomalacia, were treated with small doses of 25-HCC during full metabolic balance studies; rapid healing followed administration of 25-HCC by mouth in doses of 10-45 mug daily, which is well below the effective dose range of calciferol in this condition. These findings provided further evidence that anticonvulsant osteomalacia results from hepatic enzyme induction which, by increasing the metabolism of cholecalciferol to inactive compounds, lowers 25-HCC levels in patients whose dietary vitamin D intake and exposure to sunlight are otherwise adequate. Results also indicated that under certain circumstances 25-HCC may have considerably stronger antirachitic potency in man than has hitherto been recognized.

Adolescent↗

PubMed1972

Rickets in Glasgow Pakistanis.

Explore the source record for details and available documents.

Adolescent↗

PubMedDate not supplied

Muscle breakdown and repair in polymyositis: a case study.

Muscle breakdown and repair were measured by metabolic balance techniques in a patient with polymyositis who was being treated with prednisolone and azathioprine. Changes in body muscle mass that had been estimated from nitrogen and phosphorus balances correlated with antropometric assessments of thigh muscle mass and quadriceps strength. Decline in muscle strength was associated with a net rate of muscle breakdown of 148 g/day. Recovery was associated with a net rate of muscle repair of up to 100 g/day. Early reduction in corticosteroid treatment appeared to enhance the rate of repair. Changes in the isometric contraction force of the quadriceps muscle (but not in clinical symptoms, plasma creatine kinase [CK] or erythrocyte sedimentation rate [ESR] were found to reliably indicate whether the muscle was in a state of breakdown or repair. Treatment of the individual patient may be quantitatively monitored by metabolic balance studies or, more simply, by measurement of muscle strength.

Adult↗

PubMedDate not supplied

Needle biopsy of skeletal muscle: a review of 10 years experience.

Over 1,000 needle biopsies have been carried out at University College Hospital in London. Needle biopsy has been used by us for histochemical and electron microscopic examination of muscle during the diagnosis and treatment of neuropathic and myopathic disorders, for the diagnosis of mitochondrial myopathies, to study the course of recovery in polymyositis, and for investigations into muscle changes in systemic lupus erythematosus (SLE) and other autoimmune conditions. We have developed a microprocessor system for the measurement of muscle fiber areas, and needle biopsy specimens provide suitable material for such measurements. We have also used needle biopsy specimens for studies of protein turnover using stable isotopes and for trace metal and electrolyte analyses. Needle biopsy is safe and rapid. As the patient usually experiences only minimal discomfort and there is no permanent scar, repeat biopsies are well tolerated allowing follow-up studies after treatment.

Adolescent↗

PubMedDate not supplied

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.

Adenosine Triphosphatases↗

PubMedDate not supplied

Changes in plasma inorganic phosphorus and alkaline phosphatase activity during the adolescent growth spurt.

Longitudinal data on changes in the concentrations of plasma inorganic phosphorus and plasma alkaline phosphatase activity in 23 girls and 44 boys during the adolescent growth spurt are reported together with the height velocities, ages and sexual maturity ratings. The average age at the peak of the growth spurt was 12.5 years in the girls and 14.1 years in the boys with mean annual height gains of 7.0 and 9.7 cm/year respectively. In both sexes, plasma alkaline phosphatase activity rose and fell with the growth velocity during the growth spurt. Plasma inorganic phosphorus rose to reach a peak in the 4 months before the peak of the growth spurt in height; this rise was statisically significant in the boys but not in the girls. Values subsequently fell rapidly towards the normal adult concentrations. Plasma calcium, total protein, and albumin concentrations were also followed during this time, but were not at any point significantly different from normal adult values. These findings provide a guide for the interpretation of plasma biochemistry in adolescent patients.

Adolescent↗

PubMedDate not supplied

Changes in plasma urate, creatinine, alkaline phosphatase and the 24 hours excretion of hydroxyproline during sexual maturation in adolescents.

The relative concentrations of plasma uric acid and creatinine, the alkaline phosphatase activities and the 24 hour urinary excretion of hydroxyproline together with sexual maturity ratings are reported in a population of normal British schoolchildren studied longitudinally over a three-year period. The children were all of European origin and their ages ranged from 7 to 17 years. Plasma urate rose sharply during puberty in the boys but not in the girls. Plasma creatinine rose in both sexes during maturation. Plasma alkaline phosphatase activity rose to a peak at genital maturity 3(G3) in boys and breast maturity 2(B2) in girls and subsequently fell rapidly in both sexes. The 24-hour urinary secretion of hydroxyproline was high in young boys and rose to a peak during G3 and G4 and then fell rapidly. In girls there was no significant peak in concentrations, although there was a fall during B4 and B5, and levels were higher throughout puberty than those reported for adult females.

Adolescent↗

PubMedDate not supplied

A cross-sectional survey of upper and lower limb strength in boys and girls during childhood and adolescence.

Changes in height and weight during childhood and adolescence are well documented, yet there is comparatively little comprehensive information about muscular development during this time. In a cross-sectional survey standing height, body weight and isometric strength of the elbow flexor and quadriceps muscles have been measured in 267 boys and 284 girls aged from 5 to 17 years. All the children were from private London schools. The mean heights and weights for each age group were between the 50th and 75th centiles for British children. The strength of both muscle groups in the boys and girls rose steadily in each age group from 8 to 12 years, after which there was a rapid increase in strength of both the quadriceps and elbow flexors in boys which continued even when growth in height and body weight had virtually ceased. In the pre-adolescent phase of growth, muscle strength of the elbow flexors and quadriceps increased as a function of height squared and cubed respectively, suggesting that stretch as a result of elongation of the long bones, and for the quadriceps, loading, may be the primary stimuli during this phase. In the postpubertal phase some other stimulus, such as a direct action of hormones on the muscle, must be responsible for the continued increase in strength in the boys.

Adolescent↗

PubMedDate not supplied

Hormonal factors in the development of differences in strength between boys and girls during adolescence: a longitudinal study.

The development of elbow flexor (biceps) and knee extensor (quadriceps) strength has been followed in a mixed longitudinal study of 50 boys and 50 girls from the age of 8 to 17 years. Sex differences in strength emerged at the time of peak height velocity and were especially marked for the biceps. Data for individual children were aligned to the time of peak height velocity and associations between strength, height, weight and circulating testosterone were investigated using multi-level modelling. The results show that, for girls, quadriceps strength is proportional to height and weight while for boys there is an additional factor which can be fully attributed to increasing levels of testosterone. Testosterone is important in explaining differences in biceps strength between the sexes but an additional factor is also required. It is suggested that, in addition to a direct effect on muscle, testosterone could have a second indirect action on biceps strength by promoting growth in length of the humerus as part of the general development of the male upper limb girdle.

Adolescent↗