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Bone Sites (bone + site)
Selected AbstractsThreshold for perception of vibration is lower at glabrous skin than at subcutaneous bone sitesEUROPEAN JOURNAL OF NEUROLOGY, Issue 2 2006O. S. A. Oluwole No abstract is available for this article. [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] Long-Term Sensitivity of Uterus and Hypothalamus/Pituitary Axis to 17,-Estradiol Is Higher Than That of Bone in Rats,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 11 2004Reinhold G Erben MD Abstract We examined the long-term sensitivity of uterus and bone to low-dose 17,-estradiol in a 4-month experiment in OVX rats and found that a dose of estradiol that fully protected against uterine atrophy did not protect against bone loss. Our results suggest higher estrogen sensitivity of the uterus compared with bone. Introduction: Estrogen is essential for the function of reproductive tissues and for the normal acquisition and maintenance of bone mass in females. This study was designed to examine the long-term sensitivity of the uterus and bone to low-dose estrogen. Materials and Methods: In preliminary experiments, we determined the lowest subcutaneous dose of 17,-estradiol able to fully protect against uterine atrophy in ovariectomized (OVX) rats. This dose was found to be 1.5 ,g/kg, given five times per week. Subsequently, groups of sham-operated (SHAM) or OVX 6-month-old rats (n = 8 each) were subcutaneously injected with vehicle or 1.5 ,g/kg 17,-estradiol five times per week. All animals were killed 4 months after surgery. Serum osteocalcin and urinary deoxypyridinoline were measured as biochemical markers of bone turnover. Bones were analyzed by bone histomorphometry and pQCT. Results and Conclusions: Our study clearly showed that a dose of estradiol that restores physiological estradiol serum levels, fully maintains uterine weight in OVX rats at the SHAM control level, and suppresses serum follicle-stimulating hormone (FSH) by 67% relative to OVX vehicle controls does not provide significant protection against OVX-induced bone loss at different cancellous and cortical bone sites. We conclude that the long-term sensitivity of the uterus and the hypothalamus/pituitary axis to 17,-estradiol is higher than that of bone in rats. [source] Local biochemical markers of bone turnover: relationship to subsequent density of healing alveolar bone defectsJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 3 2004Richard A. Reinhardt Abstract Objectives: This pilot study was designed to test whether biochemical markers of bone turnover in washes of periosteal or trabecular alveolar bone surfaces could be correlated with increases in bone density of an adjacent healing implant socket. Methods: Ten subjects had a canula inserted into the alveolar crest and sterile phosphate-buffered saline was washed over the periosteal and trabecular surfaces and collected. Surgical flaps were reflected, 5 mm diameter bone cores were removed from the bone wash site, and standardized radiographs were taken. The sites were allowed to heal for 12 weeks, and radiographs were repeated. Bone washes of the healing sites were also collected after 2 and 12 weeks. Washes were analysed for bone turnover markers osteocalcin (OC; radioimmunoassay) and C-terminal telopeptide of Type 1 collagen (ICTP; enzyme-linked immunosorbent assay (ELISA)), and blood component albumin (ALB; ELISA). Changes in bone density during healing were determined by radiographic absorptiometry. Results: OC/ALB and ICTP/ALB ratios were higher for trabecular than periosteal washes at baseline (p0.01). Trabecular OC/ALB and ICTP/ALB were inversely correlated with increasing bone density of the healing bone core socket (r=,0.72, p=0.03; Pearson's correlation coefficient). Conclusions: Biochemical markers of bone turnover in bone washes of specific alveolar bone sites may prove helpful in predicting how the bone density will increase around healing dental implants. [source] Role of Calcium in Bone Health During ChildhoodNUTRITION REVIEWS, Issue 9 2000Karen S. Wosje M.S. A discussion of observational and longitudinal studies examining the effect of early-life calcium intake on bone health is provided. A critical analysis of pediatric calcium supplementation trials is conducted by determining annualized percent changes in bone mineral density (BMD). The focus of the analysis is to identify consistent findings at specific bone sites, determine whether effects differed by the age of children studied, and establish the relationship between bone changes and baseline calcium intake. We found tftat increases in BMD owing to higher calcium intake among children appear to occur primarily in cortical bone sites, are most apparent among populations with low baseline calcium intakes, and do not seem to persist beyond the calcium supplementation period. Older (e.g., pubertal) children appear to have greater annual increases in lumbar BMD than younger (e.g., prepubertal) children. The annual percent increase in midradius BMD appears to be greater at higher intakes among the older children, but such a relationship is less apparent among the younger children. [source] Local ex vivo gene therapy with bone marrow stromal cells expressing human BMP4 promotes endosteal bone formation in miceTHE JOURNAL OF GENE MEDICINE, Issue 1 2004Xiao S. Zhang Abstract Background Bone loss in osteoporosis is caused by an imbalance between resorption and formation on endosteal surfaces of trabecular and cortical bone. We investigated the feasibility of increasing endosteal bone formation in mice by ex vivo gene therapy with bone marrow stromal cells (MSCs) transduced with a MLV-based retroviral vector to express human bone morphogenetic protein 4 (BMP4). Methods We assessed two approaches for administering transduced MSCs. ,-Galactosidase (,-Gal) transduced C57BL/6J mouse MSCs were injected intravenously via tail vein or directly injected into the femoral bone marrow cavity of non-marrow-ablated syngenic recipient mice and bone marrow cavity engraftment was assessed. BMP4- or ,-Gal-transduced cells were injected into the femoral bone marrow cavity and effects on bone were evaluated by X-ray, peripheral quantitative computed tomography (pQCT), and histology. Results After tail-vein injection less than 20% of recipient mice contained ,-Gal-positive donor cells in femur, humerus or vertebra marrow cavities combined, and in these mice only 0.02,0.29% of injected cells were present in the bone marrow. In contrast, direct intramedullary injection was always successful and an average of 2% of injected cells were present in the injected femur marrow cavity 24 hours after injection. Numbers of donor cells decreased over the next 14 days. Intramedullary injection of BMP4-transduced MSCs induced bone formation. Trabecular bone mineral density (BMD) determined by pQCT increased 20.5% at 14 days and total BMD increased 6.5% at 14 days and 10.4% at 56 days. Conclusions The present findings support the feasibility of using ex vivo MSC-based retroviral gene therapy to induce relatively sustained new bone formation, with normal histological appearance, at endosteal bone sites. Copyright © 2004 John Wiley & Sons, Ltd. [source] Clinical Experience of TiUniteÔ Implants: A 5-year Cross-Sectional, Retrospective Follow-Up StudyCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 2010Bertil Friberg DDS ABSTRACT Background: Little is known of the long-term clinical and radiographic performance of moderately rough surface implants. Purpose: The aim of the present retrospective investigation was to study two pioneer cohorts of patients, that is, the first patients to receive Brånemark System® implants with a moderately rough surface (TiUniteÔ, Nobel Biocare AB, Göteborg, Sweden) at the present clinic. TiUnite implants were inserted either in compromised bone sites in a mixed-mouth concept together with turned implants or used solely. Patients were followed up over a period of 5 years with regard to implant survival and the marginal bone response. Materials and Methods: Patients who received both implant types (mixed group) comprised 41 subjects, and the second group (TiUnite group) comprised 70 subjects. A total of 110 turned and 68 TiUnite implants were placed in the mixed group, and 212 TiUnite implants in the TiUnite group. Follow-up radiographs were obtained at prosthesis placement and at the 1- and 5-year check-ups, and examined by independent observers. Results: One turned (0.9%) and two TiUnite (2.9%) implants failed in the mixed group, and three implants (1.6%) failed in the TiUnite group, indicating no significant differences between surfaces or groups (p < .05). The mean marginal bone loss at 5 years was 0.6 mm to 0.8 mm, also indicating no significant differences for the two implant types tested in the mixed group. Conclusions: Cumulative survival rates for the two implant surfaces were favorable at 5 years, and the marginal bone loss was low and similar for both implant surfaces. [source] Bone Response Inside Free-Form Fabricated Macroporous Hydroxyapatite Scaffolds with and without an Open MicroporosityCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 2 2007Johan Malmström DDS ABSTRACT Background:, The technique of free-form fabrication enables the production of controlled macroporous geometry inside ceramic scaffolds. Using scaffolds with identical macropore design makes it possible to study a relevant biological response linked to other specific changes of the material. Purpose:, This study investigates the role of open micropores in hydroxyapatite (HA) scaffold during early bone healing to quantitatively ascertain whether microporosity in otherwise identical macroporous HA scaffolds can influence the bone response in rabbit tibia and femur at 6 weeks. Materials and Methods:, HA scaffolds (Ø: 3.8 mm) with and without microporosity were randomly installed in both cortical and trabecular bone sites of New Zealand White rabbits. The animals were sacrificed 6 weeks after surgery. Ground sections obtained from en bloc tissues containing scaffold and recipient bone were subjected to histological evaluation and histomorphometric analysis. Results:, Microscopy showed elevated amounts of bone ingrowth and bone contact inside the microporous HA (mHA) group as compared with non-mHA. Conclusion:, The current study indicates that the presence of open scaffold microporosity in HA, as determined by the fabrication process, enhances the ability of ceramic scaffolds to promote bone ingrowth and bone contact. [source] | ||||||||||