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Biomedical subjects

A E Bennett

Publications and source records attributed to A E Bennett.

At least 19 recordsLinked to original sources

Insulin-like growth factors I and II in children with systemic onset juvenile arthritis.

Systemic onset juvenile arthritis (JA) has been associated with growth failure in children whether or not treated with adrenocorticosteroids. Growth hormone secretion has been reported to be normal, but production of insulin-like growth factors has not been studied. We measured serum concentrations of insulin-like growth factor I and II in a group of children with systemic JA at different times, and during treatment with only nonsteroidal antiinflammatory therapy or while receiving prednisone. Mean concentrations of insulin-like growth factor I and II were below normal for age whether or not prednisone was being given. Growth failure during periods of active disease was observed in both groups. Only 4 of 11 prepubertal children in whom growth rates were measured grew 4.5 cm or more/year. However, longitudinal studies of individual children showed that lowest growth rates occurred while taking prednisone and that growth rates were not correlated to insulin-like growth factor levels.

Arthritis, Juvenile

Purification and comparison of the receptors for insulin and insulin like growth factor I.

The insulin-like growth factors are structurally and biologically similar to insulin. The receptor sites for insulin-like growth factor-I have recently been shown to have a sub-unit structure very similar if not identical to insulin. We have compared the behavior of insulin and insulin-like growth factor-I receptors during purification using gel filtration, lectin affinity chromatography, insulin affinity chromatography, and gel electrophoresis. We demonstrate the remarkably similar physicochemical characteristics of these two receptors, but have achieved complete separation by the use of insulin affinity chromatography.

Affinity Labels

Insulin-like growth factors I and II: aging and bone density in women.

Serum concentrations of insulin-like growth factors (IGF) were measured by RIA in 57 normal women, ages 30 - 90 yr, and in 29 untreated women with postmenopausal osteoporosis and vertebral compression fractures, ages 55 - 75 yr. These values were correlated with bone mineral density (BMD) of the distal and midradius assessed by single photon absorptiometry and of the lumbar spine assessed by dual photon absorptiometry as well as serum and urinary calcium, phosphorus, creatinine, alkaline phosphatase, immunoreactive PTH, urinary hydroxyproline, and creatinine clearance. Serum IGF-I levels declined markedly with age (r = -0.47, P less than 0.001). Serum IGF-II levels decreased only slightly with age, and this decrease was not statistically significant. Although BMD at all three scanning sites also declined significantly with age, neither serum IGF-I nor II concentrations correlated with BMD when age was held constant. In women with postmenopausal osteoporosis, serum IGF-I and II did not differ from the concentrations in normal women of similar age and did not correlate with BMD. In neither group was a correlation between serum IGF-I or II and serum or urinary proteins or cations found. Thus, there was no evidence that impaired synthesis of IGF-I and II contributes to pathogenesis of the syndrome of Type I (postmenopausal) osteoporosis, which is characterized by accelerated loss of trabecular bone and vertebral compression fractures. The possibility remains, however, that decreasing concentrations of serum IGF-I play a role in the more gradual loss of bone with aging (Type II osteoporosis) in which impared bone formation at the cellular level has been demonstrated.

Adult

Disability: a model and measurement technique.

Current methods of ranking or scoring disability tend to be arbitrary. A new method is put forward on the hypothesis that disability progresses in regular, cumulative patterns. A model of disability is defined and tested with the use of Guttman scale analysis. Its validity is indicated on data from a survey in the community and from postsurgical patients, and some factors involved in scale variation are identified. The model provides a simple measurement technique and has implications for the assessment of individual disadvantage, for the prediction of progress in recovery or deterioration, and for evaluation of the outcome of treatment regimes.

Activities of Daily Living

Management and advice at the grass roots.

The new management structure of the National Health Service leaves a gap between multidisciplinary management at district level and the multiprofessional clinical teams caring for patients. This gap is not satisfactorily bridged by single-profession sector management or existing advisory machinery. This is most clearly seen for community services, and experience of a possible solution in an experimental community hospital setting is described.

Community Health Services