Search results for "Bone growth"
showing 10 items of 20 documents
Osseoconductivity of a Specific Streptavidin-Biotin-Fibronectin Surface Coating of Biotinylated Titanium Implants - A Rabbit Animal Study
2015
Background Biofunctionalized implant surfaces may accelerate bony integration and increase long-term stability. Purpose The aim of the study was to evaluate the osseous reaction toward biomimetic titanium implants surfaces coated with quasicovalent immobilized fibronectin in an in vivo animal model. Materials and Methods A total of 84 implants (uncoated [control 1, n = 36], streptavidin–biotin coated [test 1, n = 24], streptavidin–biotin–fibronectin coated [test 2, n = 24]) were inserted 1 mm supracortically in the proximal tibia of 12 rabbits. The samples were examined after 3 and 6 weeks. Total bone-implant contact (tBIC; %), bone-implant contact in the cortical (cBIC; %) and in the spong…
Lrp4, a Novel Receptor for Dickkopf 1 and Sclerostin, Is Expressed by Osteoblasts and Regulates Bone Growth and Turnover In Vivo
2009
Lrp4 is a multifunctional member of the low density lipoprotein-receptor gene family and a modulator of extracellular cell signaling pathways in development. For example, Lrp4 binds Wise, a secreted Wnt modulator and BMP antagonist. Lrp4 shares structural elements within the extracellular ligand binding domain with Lrp5 and Lrp6, two established Wnt co-receptors with important roles in osteogenesis. Sclerostin is a potent osteocyte secreted inhibitor of bone formation that directly binds Lrp5 and Lrp6 and modulates both BMP and Wnt signaling. The anti-osteogenic effect of sclerostin is thought to be mediated mainly by inhibition of Wnt signaling through Lrp5/6 within osteoblasts. Dickkopf1 …
Beyond the functional matrix hypothesis: a network null model of human skull growth for the formation of bone articulations.
2014
Craniofacial sutures and synchondroses form the boundaries among bones in the human skull, providing functional, developmental and evolutionary information. Bone articulations in the skull arise due to interactions between genetic regulatory mechanisms and epigenetic factors such as functional matrices (soft tissues and cranial cavities), which mediate bone growth. These matrices are largely acknowledged for their influence on shaping the bones of the skull; however, it is not fully understood to what extent functional matrices mediate the formation of bone articulations. Aiming to identify whether or not functional matrices are key developmental factors guiding the formation of bone articu…
Potential Antioxidant Activity of Calcium and Selected Oxidative Stress Markers in Lead- and Cadmium-Exposed Workers
2020
Occupational lead (Pb) and cadmium (Cd) exposure occurs during processing and casting of nonferrous metals such as zinc. In contrast to Pb and Cd, Ca is essential for living organisms due to its important role in a multitude of functions, from cell signaling to bone growth. Pb and Cd exposure affects calcium metabolism in various ways. The aim of this study was to investigate the blood levels of Pb, Cd, and Ca and the levels of selected oxidative stress biomarkers in workers exposed to Pb and Cd. Population groups included 264 male employees in a lead-zinc smelter. The study population was divided into two subgroups based on the median of Ca serum level (2.42 mmol/l): the low-Ca-level group…
Concerted actions of insulin-like growth factor 1, testosterone, and estradiol on peripubertal bone growth: a 7-year longitudinal study.
2011
A better understanding of how bone growth is regulated during peripuberty is important for optimizing the attainment of peak bone mass and for the prevention of osteoporosis in later life. In this report we used hierarchical models to evaluate the associations of insulin-like growth factor 1 (IGF-1), estradiol (E(2) ), and testosterone (T) with peripubertal bone growth in a 7-year longitudinal study. Two-hundred and fifty-eight healthy girls were assessed at baseline (mean age 11.2 years) and at 1, 2, 3.5, and 7 years. Serum concentrations of IGF-1, E(2) , and T were determined. Musculoskeletal properties in the left lower leg were measured using peripheral quantitative computed tomography …
Growth patterns at distal radius and tibial shaft in pubertal girls: a 2-year longitudinal study.
2005
Bone changes, in terms of both size and BMD, were assessed longitudinally in pubertal girls. Before puberty, BMD at the distal radius declined, whereas bone size increased, suggesting that normal growing girls experience a transient period of increased bone fragility. This could explain the elevated low-trauma forearm fracture rates reported in earlier studies. Introduction: Longitudinal data on bone growth during puberty are sparse. Such information is needed to understand the sequence of biological changes, the physical and mechanical consequences for the growing skeleton, and the implications for later life. Materials and Methods: The geometric properties and volumetric BMD (vBMD) of the…
Formation of nanosized strontium substituted hydroxyapatites
2012
Incorporation of specific elements into calcium phosphates offers the combination of a bioactive material and a therapeutic effect. This is important for improving the integration of implants as well as treating medical conditions. Strontium is a suitable candidate and displays the ability to stimulate bone growth and reducing bone resorption. This study investigated the formation of strontium carbonated hydroxyapatite nanoparticles from an amorphous phase. Crystallization of carbonated hydroxyapatite occurred at 585 o C, but samples with an intended 25% and 75% replacement of calcium with strontium crystallized at 624 o C. Heat treatment at the crystallization temperature revealed that str…
Dose-dependent osteoinductive effects of bFGF in rabbits.
2009
Growth factors lead to the induction of tissue regeneration in bone healing when coated on biomaterials. Basic fibroblast growth factor (bFGF) combines osteoinduction and neoangiogenesis. This study evaluated bFGF-coated hydroxylapatite implants in two experimental groups with 10 or 100 microg (n = 5 per group) compared with uncoated control implants in the rabbit patellar groove model. We observed an unexpected ineffectiveness compared to the control groups with no significant difference of bone growth after 35 days. However, all samples from the 100 microg experiment (control and coated implant) showed significantly stronger 19-25 day label than both 10 microg groups (control and coated i…
Differential effects of sex hormones on peri- and endocortical bone surfaces in pubertal girls.
2005
Context: The role of sex steroids in bone growth in pubertal girls is not yet clear. Bone biomarkers are indicators of bone metabolic activity, but their value in predicting bone quality has not been studied in growing girls. Objective: This study examines the association of sex hormones and bone markers with bone geometry and density in pubertal girls. Design: The study was designed as a 2-yr longitudinal study in pubertal girls. Measurements were performed at baseline and at 1and 2-yr follow-ups. Setting: The study was conducted in a university laboratory. Participants: A total of 258 10- to 13-yr-old healthy girls at the baseline participated. Methods:Peripheralquantitativecomputedtomogr…
Monitoring bone growth using quantitative ultrasound in comparison with DXA and pQCT.
2008
Quantitative ultrasound (QUS) is a safe, inexpensive, and nonradiation method for bone density assessment. QUS correlates with, and predicts fragility fractures comparable to, dual-energy X-ray absorptiometry (DXA)-derived bone mineral density (BMD) in postmenopausal women. However, its validity in monitoring bone growth in children is not well understood. Two hundred and fifty-eight 10-13 yr pubertal girls and 9 37-43 yr adults without diseases or history of medications known to affect bone metabolism were included in the 2-yr prospective study. Calcaneal broadband ultrasound attenuation (cBUA) was assessed using QUS-2 (Quidel, Santa Clara, CA), speed of sound of tibial shaft (tSOS) using …