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Bone Variables (bone + variable)
Selected AbstractsHistomorphometrical studies of vertebral bone condition in farmed rainbow trout, Oncorhynchus mykissJOURNAL OF APPLIED ICHTHYOLOGY, Issue 2 2010M.-H. Deschamps Summary A major problem for the fish farming industry is to find reliable indicators of bone condition that could help to prevent vertebral abnormalities. Here, we summarize the main results of two recent studies aiming to assess the variation of two vertebral bone variables (bone mineralization and vertebral total bone area) during rainbow trout grow-out in several French farms. We provide evidence for a wide range of variation for these parameters and for the occurrence of vertebral bone abnormalities, and new data on vertebral structure in trout reared either in various fish farms (influence of rearing conditions) or at different temperatures (influence of various growth rates). Although further experiments are needed to understand bone metabolism in trout, these findings increase our knowledge on growth and modelling of vertebrae, and provide valuable data that will enable comparisons in the future. [source] Adrenarche and Bone Modeling and Remodeling at the Proximal Radius: Weak Androgens Make Stronger Cortical Bone in Healthy Children,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 8 2003Thomas Remer Abstract Adrenarche, the physiological increase in adrenal androgen secretion, may contribute to better bone status. Proximal radial bone and 24-h urinary steroid hormones were analyzed cross-sectionally in 205 healthy children and adolescents. Positive adrenarchal effects on radial diaphyseal bone were observed. Obviously, adrenarche is one determinant of bone mineral status in children. Introduction: Increased bone mass has been reported in several conditions with supraphysiological adrenal androgen secretion during growth. However, no data are available for normal children. Therefore, our aim was to examine whether adrenal androgens within their physiological ranges may be involved in the strengthening of diaphyseal bone during growth. Methods: Periosteal circumference (PC), cortical density, cortical area, bone mineral content, bone strength strain index (SSI), and forearm cross-sectional muscle area were determined with peripheral quantitative computed tomography (pQCT) at the proximal radial diaphysis in healthy children and adolescents. All subjects, aged 6,18 years, who collected a 24-h urine sample around the time of their pQCT analysis (100 boys, 105 girls), were included in the present study, and major urinary glucocorticoid (C21) and androgen (C19) metabolites were quantified using gas chromatography-mass spectrometry. Results and Conclusions: We found a significant influence of muscularity, but not of hormones, on periosteal modeling (PC) before the appearance of pubic hair (prepubarche). Similarly, no influence of total cortisol secretion (C21) was seen on the other bone variables. However, positive effects of C19 on cortical density (p < 0.01), cortical area (p < 0.001), bone mineral content (p < 0.001), and SSI (p < 0.001),reflecting, at least in part, reduction in intracortical remodeling,were observed in prepubarchal children after muscularity or age had been adjusted for. This early adrenarchal contribution to proximal radial diaphyseal bone strength was further confirmed for all cortical variables (except PC) when, instead of C19 and C21, specific dehydroepiandrosterone metabolites were included as independent variables in the multiple regression model. During development of pubic hair (pubarche), muscularity and pubertal stage rather than adrenarchal hormones seemed to influence bone variables. Our study shows that especially the prepubarchal increase in adrenal androgen secretion plays an independent role in the accretion of proximal radial diaphyseal bone strength in healthy children. [source] Jumping Improves Hip and Lumbar Spine Bone Mass in Prepubescent Children: A Randomized Controlled TrialJOURNAL OF BONE AND MINERAL RESEARCH, Issue 1 2001Robyn K. Fuchs Abstract Physical activity during childhood is advocated as one strategy for enhancing peak bone mass (bone mineral content [BMC]) as a means to reduce osteoporosis-related fractures. Thus, we investigated the effects of high-intensity jumping on hip and lumbar spine bone mass in children. Eighty-nine prepubescent children between the ages of 5.9 and 9.8 years were randomized into a jumping (n = 25 boys and n = 20 girls) or control group (n = 26 boys and n = 18 girls). Both groups participated in the 7-month exercise intervention during the school day three times per week. The jumping group performed 100, two-footed jumps off 61-cm boxes each session, while the control group performed nonimpact stretching exercises. BMC (g), bone area (BA; cm2), and bone mineral density (BMD; g/cm2) of the left proximal femoral neck and lumbar spine (L1-L4) were assessed by dual-energy X-ray absorptiometry (DXA; Hologic QDR/4500-A). Peak ground reaction forces were calculated across 100, two-footed jumps from a 61-cm box. In addition, anthropometric characteristics (height, weight, and body fat), physical activity, and dietary calcium intake were assessed. At baseline there were no differences between groups for anthropometric characteristics, dietary calcium intake, or bone variables. After 7 months, jumpers and controls had similar increases in height, weight, and body fat. Using repeated measures analysis of covariance (ANCOVA; covariates, initial age and bone values, and changes in height and weight) for BMC, the primary outcome variable, jumpers had significantly greater 7-month changes at the femoral neck and lumbar spine than controls (4.5% and 3.1%, respectively). In repeated measures ANCOVA of secondary outcomes (BMD and BA), BMD at the lumbar spine was significantly greater in jumpers than in controls (2.0%) and approached statistical significance at the femoral neck (1.4%; p = 0.085). For BA, jumpers had significantly greater increases at the femoral neck area than controls (2.9%) but were not different at the spine. Our data indicate that jumping at ground reaction forces of eight times body weight is a safe, effective, and simple method of improving bone mass at the hip and spine in children. This program could be easily incorporated into physical education classes. [source] The impact of idiopathic childhood-onset growth hormone deficiency (GHD) on bone mass in subjects without adult GHDCLINICAL ENDOCRINOLOGY, Issue 1 2005Martin Lange Summary objective, Despite seemingly adequate growth hormone (GH) treatment during childhood, children with GH deficiency (GHD) have reduced bone mineral density (BMD) at final height. The aim was to evaluate BMD and bone mineral content (BMC) in adults treated for idiopathic childhood-onset (CO) GHD, 18 years after stopping GH treatment. subjects and methods, Twenty-six (11 females) patients with idiopathic CO GHD participated. All patients but two had been treated for isolated GHD in childhood. The childhood diagnosis was established by an insulin tolerance test (ITT) and reassessed in adulthood by an ITT (N = 21) or arginine test (n = 5), revealing that 10 patients had GHD according to adult criteria. Accordingly, the patient group was divided into (1) patients who did not have persistent GHD in adulthood and (2) patients who did have persistent adult GHD. Twenty-six healthy subjects acted as age-, gender- and body mass index (BMI)-matched controls. results, The patients who did not have persistent GHD had significantly lower IGF-I values and whole-body, femoral neck and lumbar spine BMD compared to controls [0·994 ± 0·10 vs. 1·114 ± 0·11 g/cm2 (P = 0·003), 0·842 ± 0·12 vs. 0·962 ± 0·11 g/cm2 (P = 0·006) and 1·026 ± 0·14 vs. 1·127 ± 0·13 g/cm2 (P = 0·004), respectively]. Femoral neck BMD was significantly reduced in the patients who had persistent GHD, compared to controls (0·842 ± 0·09 vs. 0·938 ± 0·11, P = 0·04). Significant correlations were observed between all bone variables and IGF-I in all subjects, whereas no correlations were observed between bone variables and GH peak levels in the 26 patients. conclusion, In conclusion, we found that (1) patients with idiopathic CO GHD, who at retest in adulthood did not have GHD according to adult criteria, had reduced serum IGF-I and BMD/BMC compared to controls. (2) This observation was also made in the patients who did have persistent GHD in adulthood. The findings may reflect the fact that the present diagnostic criteria for adult GHD (i.e. response to the ITT) do not reflect the clinical consequences of disordered GH,IGF axis in CO GHD young adults who were treated with GH in childhood. Alternatively, despite seemingly adequate GH treatment in childhood an optimal peak bone mass in adolescence may never have been reached in either of the groups. (3) IGF-I levels correlated with clinical signs of the adult GHD syndrome. We believe that further studies on the indications and diagnostic procedures for GH treatment after cessation of linear growth are necessary. [source] | ||||||||||