ABSTRACT
Animal experiments suggested a possible interaction between GH or GH-dependent growth factors and bone healing. The aim of this study was to determine whether there were any significant changes in serum levels of IGF-I and/ or the activity of its receptors while a fractured bone was healing. Serum concentrations of IGF-I and its specific binding to erythrocyte receptors (IGF-I SB) were determined in a group of 12 prepubertal children treated for long bone fractures. Results were compared to those obtained from a group of age- and sex-matched controls. Blood samples were taken from all patients two weeks following the fractures, when bone formation rate should have been maximal. We found no difference in IGF-I SB between the two groups. However, serum IGF-I levels were increased in the group of children with fractures compared to controls. Results are suggestive of a possible interaction between IGF-I and bone repair processes as other investigators have suggested on the basis of animal experiments.
Subject(s)
Bone and Bones/injuries , Erythrocytes/metabolism , Fracture Healing/physiology , Insulin-Like Growth Factor I/metabolism , Child , Female , Humans , Male , Receptor, IGF Type 1/bloodABSTRACT
Aims of the study were to assess the relationship between serum levels of IGFBP-3 with IGF-I serum levels, peak GH levels in response to two stimulation tests (PKGH) and GH urinary excretion in children, and to examine the usefulness of IGFBP-3 for diagnosis of GH deficiency. Our study group consisted of 86 children with normal stature, 12 children with normal short stature and 12 children with GHD. In all children, serum levels of IGF-I and IGFBP-3 were measured and GH urinary excretion was assessed in overnight urine collections. Children with short stature had two stimulation tests and the peak GH level was used in the analysis. IGFBP-3 SDS was strongly correlated with IGF-I SDS (r = 0.63, p < 0.001), significantly correlated with peak GH (r = 0.42, p < 0.05) and weakly, but not significantly, correlated with urinary GH excretion. Among the 12 children with GHD, only two had normal IGFBP-3 values (sensitivity 83%). In contrast, all normal short children except one had IGFBP-3 levels within the normal range, defined by the 5th and 95th percentile (specificity 92%). Sensitivity and specificity of IGF-I were respectively 67% and 50%. In conclusion, IGFBP-3 levels are strongly correlated with IGF-I levels, weakly correlated with peak GH response to provocative tests and may serve as a valuable parameter, in combination with others, in the evaluation of the GH-IGF axis.
Subject(s)
Human Growth Hormone/deficiency , Human Growth Hormone/metabolism , Insulin-Like Growth Factor Binding Protein 3/blood , Adolescent , Aging , Body Height , Child , Female , Humans , Insulin-Like Growth Factor I/metabolism , Male , Puberty , Reference Values , Sensitivity and SpecificityABSTRACT
Exposure to environmental tobacco smoke is associated with increased respiratory morbidity in young children, but few studies have assessed such exposure objectively by urinary cotinine measurements. 501 children aged 1-5 years, a random 5% sample of children attending an outpatient clinic, were classified as exposed or non-exposed to environmental tobacco smoke with a cut-off of 10 ng cotinine per mg creatinine in urine. Exposed children were 3.5 times (95% CI 1.56-7.90, p < 0.0024) more likely to have increased respiratory morbidity (three or more episodes during the previous 12 months) than non-exposed children after adjustment for potential confounding factors.
