Authors: N E Vieira R E Goans G H Weiss E Hopkins J C Marini A L Yergey
Publish Date: 2014/03/18
Volume: 67, Issue: 2, Pages: 97-100
Abstract
Children with osteogenesis imperfecta OI type III and type IV were studied using a 42Ca stable isotope technique Serum dilution kinetics of 42Ca were studied pre and postgrowth hormone GH treatment in 9 OI III age range 5–9 years and 8 OI IV patients age range 5–12 years Each subject was studied twice at baseline and following GH therapy range 1–15 years Isotopic enrichments of 42Ca were followed over 7 days using thermal ionization mass spectrometry A binding site model which describes reversible and irreversible binding of calcium Ca ions to postulated short and longterm binding sites in bone was used to analyze the kinetic data In type III patients GH treatment 1 increased the fraction of shortterm binding sites θ 0777 ± 0112 versus 0877 ± 005 respectively P= 0034 2 increased the apparent halflife of a Ca ion attached to the longterm binding site by 76 P= 0009 3 although not statistically significant P= 0098 a trend toward an increased growth rate was observed with increasing change in θ Δθ 4 patients experienced a 75 increase in growth rate during the first 6 months of treatment In type IV patients GH treatment increased the apparent halflife of a Ca ion attached to the longterm binding site by 83 P= 0048 however no trend toward an increased growth rate was observed with increasing Δθ in these patients These significant changes in Ca binding to bone may influence growth in type III patients
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