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Bone Properties (bone + property)
Selected AbstractsBone properties and muscle strength of young haemophilia patientsHAEMOPHILIA, Issue 4 2005B. Falk Summary., Purpose:, To evaluate bone properties, muscle strength and the relationship between the two, in young (7.0,17.7 years) haemophilia patients (h) and healthy boys (c). Subjects:, Twenty-seven boys with severe haemophilia and 33 healthy boys, of similar age, body mass, height, (mean ± sd for h and c, respectively: 11.2 ± 3.2 vs. 11.4 ± 2.9 years, 42.6 ± 16.6 vs. 41.6 ± 17.3 kg, 145 ± 18 vs. 146 ± 17 cm) and pubertal stage according to secondary sex characteristics, volunteered for the study. all subjects were physically inactive (as determined by questionnaire). Methods:, Subjects performed isokinetic elbow and knee extension and flexion tests at two angular velocities (biodex system ii dynamometer). Bone properties were evaluated by qualitative ultrasound (sunlight omnisenseTM), at the distal radius and tibial mid-shaft. H subjects received prophylactic factor viii treatment within the 24 h preceding testing. No test was performed in the presence of haemorrhage. Results:, Muscle strength was consistently higher in c compared with h, especially in the lower limbs (e.g. knee extension: 1.80 ± 0.44 vs 1.48 ± 0.53 N·m·kg,1 body mass, respectively, p = 0.01). No differences were observed in tibial or radial speed of sound between groups. Correlations between muscle strength and bone properties were observed only in the lower limbs and only in c (r = 0.37,0.48). Conclusion:, Muscle strength, especially lower limbs' strength, was lower in haemophilia patients compared with a matched, similarly inactive population of healthy boys. Nevertheless, at this age range, this relative weakness is not associated with inferior bone properties. [source] Association Between Exercise and Pubertal BMD Is Modulated by Estrogen Receptor , Genotype,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 11 2004Miia Suuriniemi MSc Abstract Genetic and environmental factors contribute to bone mass, but the ways they interact remain poorly understood. This study of 245 pre- and early pubertal girls found that the PvuII polymorphism in the ER -, gene modulates the effect of exercise on BMD at loaded bone sites. Introduction: Impaired achievement of bone mass at puberty is an important risk factor for the development of osteoporosis in later life. Genetic, as well as environmental, factors contribute to bone mass, but the ways they interact with each other remain poorly understood. Materials and Methods: We investigated the interaction between a PvuII polymorphism at the ER -, gene and physical activity (PA) on the modulation of bone mass and geometry in 245 10- to 13-year-old pre- and early pubertal Finnish girls. Level of PA was assessed using a questionnaire. Bone properties were measured using DXA and pQCT. The analyses were controlled for the effects of Tanner stage and body size index. Results: Girls with heterozygote ER-, genotype (Pp) and high PA had significantly higher bone mass and BMD, as well as thicker cortex, at loaded bone sites than their low-PA counterparts. No differences were found in bone properties of the distal radius, which is not a weight-bearing bone. Bone properties did not differ in either homozygote groups (PP and pp) regardless of the PA level. Conclusions: These findings suggest that the PvuII polymorphism in the ER -, gene may modulate the effect of exercise on BMD at loaded bone sites. The heterozygotes may benefit most from the effect of exercise, whereas neither of the homozygote groups received any significant improvement from high PA. Furthermore, high PA may hide the genetic influence on bone. Indeed, it seems that one may compensate one's less favorable Pp genotype by increasing leisure PA at early puberty. [source] Bone properties and muscle strength of young haemophilia patientsHAEMOPHILIA, Issue 4 2005B. Falk Summary., Purpose:, To evaluate bone properties, muscle strength and the relationship between the two, in young (7.0,17.7 years) haemophilia patients (h) and healthy boys (c). Subjects:, Twenty-seven boys with severe haemophilia and 33 healthy boys, of similar age, body mass, height, (mean ± sd for h and c, respectively: 11.2 ± 3.2 vs. 11.4 ± 2.9 years, 42.6 ± 16.6 vs. 41.6 ± 17.3 kg, 145 ± 18 vs. 146 ± 17 cm) and pubertal stage according to secondary sex characteristics, volunteered for the study. all subjects were physically inactive (as determined by questionnaire). Methods:, Subjects performed isokinetic elbow and knee extension and flexion tests at two angular velocities (biodex system ii dynamometer). Bone properties were evaluated by qualitative ultrasound (sunlight omnisenseTM), at the distal radius and tibial mid-shaft. H subjects received prophylactic factor viii treatment within the 24 h preceding testing. No test was performed in the presence of haemorrhage. Results:, Muscle strength was consistently higher in c compared with h, especially in the lower limbs (e.g. knee extension: 1.80 ± 0.44 vs 1.48 ± 0.53 N·m·kg,1 body mass, respectively, p = 0.01). No differences were observed in tibial or radial speed of sound between groups. Correlations between muscle strength and bone properties were observed only in the lower limbs and only in c (r = 0.37,0.48). Conclusion:, Muscle strength, especially lower limbs' strength, was lower in haemophilia patients compared with a matched, similarly inactive population of healthy boys. Nevertheless, at this age range, this relative weakness is not associated with inferior bone properties. [source] Black bear femoral geometry and cortical porosity are not adversely affected by ageing despite annual periods of disuse (hibernation)JOURNAL OF ANATOMY, Issue 2 2007Meghan E. McGee Abstract Disuse (i.e. inactivity) causes bone loss, and a recovery period that is 2,3 times longer than the inactive period is usually required to recover lost bone. However, black bears experience annual disuse (hibernation) and remobilization periods that are approximately equal in length, yet bears maintain or increase cortical bone material properties and whole bone mechanical properties with age. In this study, we investigated the architectural properties of bear femurs to determine whether cortical structure is preserved with age in bears. We showed that cross-sectional geometric properties increase with age, but porosity and resorption cavity density do not change with age in skeletally immature male and female bears. These findings suggest that structural properties substantially contribute to increasing whole bone strength with age in bears, particularly during skeletal maturation. Porosity was not different between skeletally immature and mature bears, and showed minimal regional variations between anatomical quadrants and radial positions that were similar in pattern and magnitude between skeletally immature and mature bears. We also found gender dimorphisms in bear cortical bone properties: females have smaller, less porous bones than males. Our results provide further support for the idea that black bears possess a biological mechanism to prevent disuse osteoporosis. [source] Long-Term Leisure Time Physical Activity and Properties of Bone: A Twin Study,,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 8 2009Hongqiang Ma Abstract Effects of physical activity on bone properties, when controlled for genetic effects, are not fully understood. We aimed to study the association between long-term leisure time physical activity (LTPA) and bone properties using twin pairs known to be discordant for leisure time physical activity for at least 30 yr. Volumetric BMD and geometric properties were measured at the tibia shaft and distal end using pQCT in 16 middle-aged (50,74 yr) same-sex twin pairs (seven monozygotic [MZ] and nine dizygotic [DZ] pairs) selected from a population-based cohort. Paired differences between active and inactive co-twins were studied. Active members of MZ twin pairs had larger cortical bone cross-sectional area (intrapair difference: 8%, p = 0.006), thicker cortex (12%, p = 0.003), and greater moment of inertia (Imax, 20%, p = 0.024) at the tibia shaft than their inactive co-twins. At the distal tibia, trabecular BMD (12%, p = 0.050) and compressive strength index (18%, p = 0.038) were also higher in physically active MZ pair members than their inactive co-twins. The trends were similar, but less consistently so, in DZ pairs as in MZ pairs. Our genetically controlled study design shows that LTPA during adulthood strengthens bones in a site-specific manner, that is, the long bone shaft has a thicker cortex, and thus higher bending strength, whereas the distal bone has higher trabecular density and compressive strength. These results suggest that LTPA has a potential causal role in decreasing the long-term risk of osteoporosis and thus preventing osteoporotic fractures. [source] Ovariectomy-Induced Bone Loss Varies Among Inbred Strains of Mice,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 7 2005Mary L Bouxsein PhD Abstract There is a subset of women who experience particularly rapid bone loss during and after the menopause. However, the factors that lead to this enhanced bone loss remain obscure. We show that patterns of bone loss after ovariectomy vary among inbred strains of mice, providing evidence that there may be genetic regulation of bone loss induced by estrogen deficiency. Introduction: Both low BMD and increased rate of bone loss are risk factors for fracture. Bone loss during and after the menopause is influenced by multiple hormonal factors. However, specific determinants of the rate of bone loss are poorly understood, although it has been suggested that genetic factors may play a role. We tested whether genetic factors may modulate bone loss subsequent to estrogen deficiency by comparing the skeletal response to ovariectomy in inbred strains of mice. Materials and Methods: Four-month-old mice from five inbred mouse strains (C3H/HeJ, BALB/cByJ, CAST/EiJ, DBA2/J, and C57BL/6J) underwent ovariectomy (OVX) or sham-OVX surgery (n = 6-9/group). After 1 month, mice were killed, and ,CT was used to compare cortical and trabecular bone response to OVX. Results: The effect of OVX on trabecular bone varied with mouse strain and skeletal site. Vertebral trabecular bone volume (BV/TV) declined after OVX in all strains (,15 to ,24%), except for C3H/HeJ. In contrast, at the proximal tibia, C3H/HeJ mice had a greater decline in trabecular BV/TV (,39%) than C57BL/6J (,18%), DBA2/J (,23%), and CAST/EiJ mice (,21%). OVX induced declines in cortical bone properties, but in contrast to trabecular bone, the effect of OVX did not vary by mouse strain. The extent of trabecular bone loss was greatest in those mice with highest trabecular BV/TV at baseline, whereas cortical bone loss was lowest among those with high cortical bone parameters at baseline. Conclusions: We found that the skeletal response to OVX varies in a site- and compartment-specific fashion among inbred mouse strains, providing support for the hypothesis that bone loss during and after the menopause is partly genetically regulated. [source] Low Skeletal Muscle Mass Is Associated With Poor Structural Parameters of Bone and Impaired Balance in Elderly Men,The MINOS Study,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 5 2005Pawel Szulc MD Abstract In 796 men, 50-85 years of age, decreased relative skeletal muscle mass index was associated with narrower bones, thinner cortices, and a consequent decreased bending strength (lower section modulus), as well as with impaired balance and an increased risk of falls. Introduction: In men, appendicular skeletal muscle mass (ASM) is correlated positively with BMC and areal BMD (aBMD). In elderly men, low muscle mass and strength (sarcopenia) is associated with difficulties in daily living activities. The aim of this study was to evaluate if ASM is correlated with bone size, mechanical properties of bones, balance, and risk of falls in elderly men. Materials and Methods: This study used 796 men, 50-85 years of age, belonging to the MINOS cohort. Lifestyle factors were evaluated by standardized questionnaires. Estimates of mechanical bone properties were derived from aBMD measured by DXA. ASM was estimated by DXA. The relative skeletal muscle mass index (RASM) was calculated as ASM/(body height)2.3. Results: After adjustment for age, body size, tobacco smoking, professional physical activity, and 17,-estradiol concentration, RASM was correlated positively with BMC, aBMD, external diameter, and cortical thickness (r = 0.17-0.34, p < 0.0001) but not with volumetric BMD. Consequently, RASM was correlated with section modulus (r = 0.29-0.39, p < 0.0001). Men in the lowest quartile of RASM had section modulus of femoral neck and distal radius lower by 12-18% in comparison with men in the highest quartile of RASM. In contrast, bone width was not correlated with fat mass, reflecting the load of body weight (except for L3), which suggests that the muscular strain may exert a direct stimulatory effect on periosteal apposition. After adjustment for confounding variables, a decrease in RASM was associated with increased risk of falls and of inability to accomplish clinical tests of muscle strength, static balance, and dynamic balance (odds ratio per 1 SD decrease in RASM, 1.31-2.23; p < 0.05-0.001). Conclusions: In elderly men, decreased RASM is associated with narrower bones and thinner cortices, which results in a lower bending strength. Low RASM is associated with impaired balance and with an increased risk of falls in elderly men. It remains to be studied whether low RASM is associated with decreased periosteal apposition and with increased fracture risk in elderly men, and whether the difference in skeletal muscle mass between men and women contributes to the between-sex difference in fracture incidence. [source] Association Between Exercise and Pubertal BMD Is Modulated by Estrogen Receptor , Genotype,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 11 2004Miia Suuriniemi MSc Abstract Genetic and environmental factors contribute to bone mass, but the ways they interact remain poorly understood. This study of 245 pre- and early pubertal girls found that the PvuII polymorphism in the ER -, gene modulates the effect of exercise on BMD at loaded bone sites. Introduction: Impaired achievement of bone mass at puberty is an important risk factor for the development of osteoporosis in later life. Genetic, as well as environmental, factors contribute to bone mass, but the ways they interact with each other remain poorly understood. Materials and Methods: We investigated the interaction between a PvuII polymorphism at the ER -, gene and physical activity (PA) on the modulation of bone mass and geometry in 245 10- to 13-year-old pre- and early pubertal Finnish girls. Level of PA was assessed using a questionnaire. Bone properties were measured using DXA and pQCT. The analyses were controlled for the effects of Tanner stage and body size index. Results: Girls with heterozygote ER-, genotype (Pp) and high PA had significantly higher bone mass and BMD, as well as thicker cortex, at loaded bone sites than their low-PA counterparts. No differences were found in bone properties of the distal radius, which is not a weight-bearing bone. Bone properties did not differ in either homozygote groups (PP and pp) regardless of the PA level. Conclusions: These findings suggest that the PvuII polymorphism in the ER -, gene may modulate the effect of exercise on BMD at loaded bone sites. The heterozygotes may benefit most from the effect of exercise, whereas neither of the homozygote groups received any significant improvement from high PA. Furthermore, high PA may hide the genetic influence on bone. Indeed, it seems that one may compensate one's less favorable Pp genotype by increasing leisure PA at early puberty. [source] Effect of Hormone Replacement Therapy on Bone Quality in Early Postmenopausal WomenJOURNAL OF BONE AND MINERAL RESEARCH, Issue 6 2003Ep Paschalis PhD Abstract HRT is an effective prophylaxis against postmenopausal bone loss. Infrared imaging of paired iliac crest biopsies obtained at baseline and after 2 years of HRT therapy demonstrate an effect on the mineral crystallinity and collagen cross-links that may affect bone quality. Several studies have demonstrated that hormonal replacement therapy (HRT) is an effective prophylaxis against postmenopausal bone loss, although the underlying mechanisms are still debated. Infrared spectroscopy has been used previously for analyzing bone mineral crystallinity and three-dimensional structures of collagen and other proteins. In the present study, the technique of Fourier transform infrared microscopic imaging (FTIRI) was used to investigate the effect of estrogen on bone quality (arbitrarily defined as mineral/matrix ratio, mineral crystallinity/maturity, and relative ratio of collagen cross-links [pyridinoline/deH-DHLNL]) at the ultrastructural level, in mineralized, thin tissue sections from double (before and after administration of HRT regimen; cyclic estrogen and progestogen [norethisterone acetate]) iliac crest biopsy specimens from 10 healthy, early postmenopausal women who were not on any medication with known influence on calcium metabolism. FTIRI allows the analysis of undemineralized thin tissue sections (each image analyzes a 400 × 400 ,m2 area with a spatial resolution of ,6.3 mm). For each bone quality variable considered, the after-treatment data exhibited an increase in the mean value, signifying definite changes in bone properties at the molecular level after HRT treatment. Furthermore, these findings are consistent with suppressed osteoclastic activity. [source] Bone Mineral and Collagen Quality in Humeri of Ovariectomized Cynomolgus Monkeys Given rhPTH(1,34) for 18 MonthsJOURNAL OF BONE AND MINERAL RESEARCH, Issue 4 2003Eleftherios P Paschalis Abstract A recent study of ovariectomized monkeys, treated with recombinant human parathyroid hormone (rhPTH)(1,34) at 1 or 5 mg/kg/day for 18 months or for 12 months followed by 6 months withdrawal from treatment, showed significant differences in the geometry and histomorphometry of cortical bone of the midshaft humerus. To determine the extent to which the rapid bone turnover and cortical porosity induced by rhPTH(1,34) in ovariectomized monkeys modified mineral content, mineral crystal maturity and collagen maturity (cross-link distribution) in the cortical periosteal and endosteal regions, cross-sections of the cortical bone of the mid-humerus, were examined using Fourier transform infrared imaging (FTIRI). FTIRI analyses demonstrated that rhPTH(1,34) altered bone mineral and collagen properties in a dose-dependent manner. Mineral crystal maturity and collagen cross-link ratio (pyridinoline/dehydro-dihydroxylysinonorleucine) on both endosteal and periosteal surfaces decreased relative to ovariectomized animals, consistent with new bone formation. These changes were partially sustained after withdrawal of the higher dose of rhPTH(1,34), suggesting a prolonged after-effect on bone properties for at least two bone remodeling cycles. In conclusion, treatment of ovariectomized monkeys with rhPTH(1,34) had significant effects on cortical bone mineral-to-matrix ratio, mineral crystal maturity, and collagen cross-link ratio. These were fully reversible when the 1-,g rhPTH(1,34) treatment was withdrawn, but only partially reversed when the 5-,g rhPTH(1,34) dose was withdrawn. [source] Fractal Dimension of Trabecular Bone Projection Texture Is Related to Three-Dimensional MicroarchitectureJOURNAL OF BONE AND MINERAL RESEARCH, Issue 4 2000L. Pothuaud Abstract The purpose of this work was to understand how fractal dimension of two-dimensional (2D) trabecular bone projection images could be related to three-dimensional (3D) trabecular bone properties such as porosity or connectivity. Two alteration processes were applied to trabecular bone images obtained by magnetic resonance imaging: a trabeculae dilation process and a trabeculae removal process. The trabeculae dilation process was applied from the 3D skeleton graph to the 3D initial structure with constant connectivity. The trabeculae removal process was applied from the initial structure to an altered structure having 99% of porosity, in which both porosity and connectivity were modified during this second process. Gray-level projection images of each of the altered structures were simply obtained by summation of voxels, and fractal dimension (Df) was calculated. Porosity (,) and connectivity per unit volume (Cv) were calculated from the 3D structure. Significant relationships were found between Df, ,, and Cv. Df values increased when porosity increased (dilation and removal processes) and when connectivity decreased (only removal process). These variations were in accordance with all previous clinical studies, suggesting that fractal evaluation of trabecular bone projection has real meaning in terms of porosity and connectivity of the 3D architecture. Furthermore, there was a statistically significant linear dependence between Df and Cv when , remained constant. Porosity is directly related to bone mineral density and fractal dimension can be easily evaluated in clinical routine. These two parameters could be associated to evaluate the connectivity of the structure. [source] The effects of RANKL inhibition on fracture healing and bone strength in a mouse model of osteogenesis imperfectaJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2008Demetris Delos Abstract Currently, the standard treatment for osteogenesis imperfecta (OI) is bisphosphonate therapy. Recent studies, however, have shown delayed healing of osteotomies in a subset of OI patients treated with such agents. The current study sought to determine the effects of another therapy, RANKL inhibition, on bone healing and bone strength in the growing oim/oim mouse, a model of moderate to severe OI. Mice [73 oim/oim and 69 wild-type (WT)] were injected twice weekly with either soluble murine RANK (RANK-Fc) (1.5 mg/kg) or saline beginning at 6 weeks of age. At 8 weeks of age, the animals underwent transverse mid-diaphyseal osteotomies of the right femur. Therapy was continued until sacrifice at 2, 3, 4, or 6 weeks postfracture. At 6 weeks post-fracture, greater callus area (6.59,±,3.78 mm2 vs. 2.67,±,2.05 mm2, p,=,0.003) and increased radiographic intensity (mineral density) (0.48,±,0.14 vs. 0.30,±,0.80, p,=,0.005) were found in the RANK-Fc versus saline oim/oim group, indicating a delay in callus remodeling. Despite this delay, mechanical tests at 6 weeks postfracture revealed no significant differences in whole bone properties of stiffness and failure moment. Further, RANKL inhibition resulted in a greater failure moment and greater work to failure for the nonfractured contralateral WT bones compared to the nonfractured saline WT bones. Together, these results demonstrate that RANKL inhibition does not adversely affect the mechanical properties of healing bone in the oim/oim mice, and is associated with increased strength in intact bone in the WT mice. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:153,164, 2008 [source] Efficacy of the injectable calcium phosphate ceramics suspensions containing magnesium, zinc and fluoride on the bone mineral deficiency in ovariectomized ratsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 1 2008Makoto Otsuka Abstract The purpose of this study was to evaluate the therapeutic efficacy of a new calcium phosphate (CaP)-based formulation in improving the bone mineral deficiency in ovariectomized (OVX) rats. The ions release experiments for CaP preparations (G2: 0.46% Mg, 5.78% Zn, and 2.5% F; G3:3.1% Mg, 0.03% Zn, and 3.01% F; G4: 1.25% Mg, 1.77% Zn, 1.35% F) and of a Zn-TCP (G1: 6.17% Zn) powders, the initial Mg and Zn ion release rates of MZF-CaPs were performed in acetate buffer at pH 4.5 (37°C). Wistar rats were divided into six groups including a normal (not OVX) group (GN) and a control, OVX group (GC). Rats in groups GC, G1, G2, G3, G4 were OVX. Suspensions consisting of CaP preparations (G2, G3, G4) and of a Zn-TCP (G1) powders were injected in the right thighs of OVX rats in all groups except for GN and GC, once a week for 4 weeks. GN and GC rats were injected with saline solutions. Plasma was analyzed for Zn land alkaline phosphatase levels. The bone mineral density (BMD) was measured using DEXA and the bone (femur) strength determined using three-point-bending analysis. G1 and G2 groups showed high plasma Zn levels. The area under the curve of plasma Zn was significantly greater in the G1, G2, and GN groups than in the G3, G4, and GC groups (p,<,0.05). The BMD and bone mechanical strength of the right femur were significantly higher in the G1, G2, G3, and G4 groups than GC group on day 28. The right femur had significantly greater BMD and bone mechanical strength than the left femur in G1, G2, G3, and G4 groups. However, there was no significant difference in the BMD of the right femur between the G1, G2, G3, and G4 groups. Results indicate that the new injectable CaP formulations are effective in improving bone properties of OVX rats and may be useful in osteoporosis therapy. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:421,432, 2008 [source] MECHANICAL BONE PROPERTIES OF OBESE MODEL SHR/NDmcr-cp RATSCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 2007Naomi Nishii SUMMARY 1High-blood pressure or diabetes may be related to the loss of bone mass or the development of osteoporosis. We examined the mechanical bone properties of the SHR/NDmcr-cp (SHR-cp) rat, an obese strain that develops hypertension, hyperlipidaemia and insulin-independent diabetes. 2The mechanical properties of the femur of 22-week-old Wistar-Kyoto (WKY) and SHR-cp rats were measured by Peng's three-point bending procedure modified by Shintani. Femurs were then defatted and dried. After weighing, the dried bones were ashed and the ash was weighed. The values of the dry weight, ash weight and ash weight/dry weight (%) were used as a description of the physical parameters of the bone. 3All values of stiffness, strength, toughness and ductility in SHR-cp were significantly lower than those of WKY rats (P < 0.05). The value of ash weight/dry weight (%) was lower in SHR-cp rats (P < 0.01). These results showed that bone fragility was greater in SHR-cp rats, indicative of osteopenia. [source] | |||||||||||||