Search results for "Bone tissue"
showing 10 items of 78 documents
Skeletal status assessed by quantitative ultrasound and dual-energy X-ray absorptiometry in children with inflammatory bowel disease: A 2-year prospe…
2019
PURPOSE To assess the bone status in children with inflammatory bowel diseases (IBD) using quantitative ultrasound (QUS) measurement and dual-energy X-ray absorptiometry (DXA) at baseline and after two years of adequate treatment of the IBD and bone protection medication. METHODS Sixteen children (six boys) with IBD, aged 13.4±2.4 years, were examined at baseline and two years later. DXA was used to asses bone mineral density (BMD) and reference data were provided by the device's manufacturer (Hologic Explorer). QUS measurements were performed in patients and controls - 48 healthy children. RESULTS Mean Z-scores for TB- and s-BMD were significantly below zero for both, baseline and follow-u…
A collagen extraction and deuterium oxide stable isotope tracer method for the quantification of bone collagen synthesis rates in vivo.
2021
Abstract The development of safe and practical strategies to prevent weakening of bone tissue is vital, yet attempts to achieve this have been hindered by a lack of understanding of the short‐term (days‐weeks) physiology of bone collagen turnover. To address this, we have developed a method to quantify bone collagen synthesis in vivo, using deuterium oxide (D2O) tracer incorporation techniques combined with gas chromatography pyrolysis isotope‐ratio mass spectrometry (GC‐pyrolysis‐IRMS). Forty‐six male and female rats from a selectively bred model ingested D2O for 3 weeks. Femur diaphyses (FEM), tibia proximal (T‐PRO), and distal (T‐DIS) epiphyses‐metaphyses and tibia mid‐shaft diaphyses (T…
Mesenchymal stem cell proliferation and differentiation on load-bearing trabecular Nitinol scaffolds.
2013
Bone tissue regeneration in load-bearing regions of the body requires high-strength porous scaffolds capable of supporting angiogenesis and osteogenesis. 70% porous Nitinol (NiTi) scaffolds with a regular 3-D architecture resembling trabecular bone were produced from Ni foams using an original reactive vapor infiltration technique. The "trabecular Nitinol" scaffolds possessed a high compressive strength of 79 MPa and high permeability of 6.9×10(-6) cm2. The scaffolds were further modified to produce a near Ni-free surface layer and evaluated in terms of Ni ion release and human mesenchymal stem cell (hMSC) proliferation (AlamarBlue), differentiation (alkaline phosphatase activity, ALP) and …
Functionalized silver doped hydroxyapatite scaffolds for controlled simultaneous silver ion and drug delivery
2017
Abstract Bacterial infections are a major problem in bone tissue regeneration, thus it is essential to incorporate antibacterial properties within the bone scaffolds. Silver compounds are frequently used as antibacterial agents to prevent bacterial infections and numerous studies have shown that silver ions can be incorporated within the biocompatible and osteoconductive biomaterial hydroxyapatite (HAp) structure, but, so far, no study has thoroughly evaluated silver ion release rates in long term. Therefore, we have established a novel carrier system for local drug delivery based on functionalized silver doped hydroxyapatite with determined long term silver ion release rates. Silver ions f…
STRUCTURAL FEATURES AND MECHANICAL PROPERTIES OF PLLA/PEARL POWDER SCAFFOLDS
2013
In order to improve the mechanical properties of scaffolds for bone tissue engineering, the present study aims to bring calcium carbonate (CaCO3) with signaling molecules, namely pearl powder, into poly(L-lactic acid) (PLLA). PLLA/aragonite and PLLA/vaterite scaffolds were successfully fabricated by the freeze-drying method. Both composite scaffolds had a similar porous structure but a different saturated content of pearl powders. For both scaffolds, the porosity decreases and yield strength increases as pearl powder content increases. Introducing pearl powders into PLLA can improve the mechanical properties of the scaffolds. The porous structure plays a crucial role in the yield strength …
Studies of Mechanical Treatment on Surface Charge of Bioactive Composites
2008
Composite materials containing a bioactive phase (sol-gel-derived bioglass) and a mechanical strength phase (aluminum oxide-porous corundum) are promising materials for repair of living tissues. The influence of mechanical treatment of composite structure containing sintered corundum and CaOSiO2-P2O5 glass system was examined by exoelectron emission and electrokinetic’s potential method. The microstructure of the biocomposite material, its mechanical properties and the processing techniques used are all very strongly interrelated.. The charge layer generated on the surface of the composite biomaterials upon deformation and the type of the electrical charge in implants plays significant role…
Effect of hydroxyapatite concentration and size on morpho-mechanical properties of PLA-based randomly oriented and aligned electrospun nanofibrous ma…
2019
The growing demand for nanofibrous biocomposites able to provide peculiar properties requires systematic investigations of processing-structure-property relationships. Understanding the morpho-mechanical properties of an electrospun scaffold as a function of the filler features and mat microstructure can aid in designing these systems. In this work, the reinforcing effect of micrometric and nanometric hydroxyapatite particles in polylactic acid-based electrospun scaffold presenting random and aligned fibers orientation, was evaluated. The particles incorporation was investigated trough Fourier transform infrared spectroscopy in attenuated total reflectance. The morphology of the nanofibers …
Optimization of electrospun polylactide-based ultrathin fibers for osteoconductive bone scaffolds
2011
Bone tissue interfacial scaffolds, which encourage cell growth, are critical determinants for clinical success after implant surgery. Over the years, a number of resorbable configurations have emerged for bone cell support and growth, but only a few have demonstrated clinical efficacy. Polymer coatings produced by electrospinning are regarded as very promising bone interfaces because of the ultrathin-scaled dimensions of its physical structure. In this study, the morphology, composition, thermal properties, and cell growth viability of a number of polylactide-based systems containing different binary and ternary formulations of this biomaterial with collagen and commercial hydroxyapatite na…
Modeling the influence of mineral content and porosity on ultrasound parameters in bone by using synthetic phantoms
1999
Model composite media − 10×15×80 mm3 bone tissue phantoms based on an epoxy resin with fillers—were made to study the influence of porosity and mineral content on ultrasound velocity and attenuation. The pores were simulated by ∼ 1 mm3 particles of a soft rubber, while the mineral content was imitated by a mineral residue of natural bone obtained by burning and grinding. The porosity and mineral content were varied in the range of 0–70% by volume with a step of 10%. The velocity, attenuation, and prevalent frequency of ultrasound were measured by the pulse transition method, using transducers with nominal frequencies 0.1, 0.2, 0.5, and 1.0 MHz. It was experimentally found that the ultrasoun…
The rapid anastomosis between prevascularized networks on silk fibroin scaffolds generated in vitro with cocultures of human microvascular endothelia…
2010
The survival and functioning of a bone biomaterial upon implantation requires a rapidly forming and stably functioning vascularization that connects the implant to the recipient. We have previously shown that human microcapillary endothelial cells (HDMEC) and primary human osteoblast cells (HOS) in coculture on various 3-D bone biomaterial scaffolds rapidly distribute and self-assemble into a morphological structure resembling bone tissue. Endothelial cells form microcapillary-like structures containing a lumen and these were intertwined between the osteoblast cells and the biomaterial. This tissue-like self-assembly occurred in the absence of exogenously added angiogenic stimuli or artific…