Search results for "Bone tissue"

A 2D-FEM Model of Nonlinear Ultrasound Propagation in Trans-cranial MRgFUS Technique

2022

Magnetic Resonance guided Focused Ultrasound (MRgFUS) is a non-invasive technique based on the thermal ablation of a target using high intensity focused ultrasound. MRgFUS treatment applied to brain is challenging due to the skull presence that attenuates ultrasound, leading to heating effects in bone region. In this study, we simulate trans-cranial nonlinear ultrasound propagation considering the detailed structure of bone tissue. We developed a 2D Finite Element (FE) model that mimics the propagation of focused ultrasound through skin, skull and brain tissue. The skull is represented as a three-layered system with two cortical tables packing a layer of trabecular bone. We assume that the …

Multinucleated giant cells in the implant bed of bone substitutes are foreign body giant cells-New insights into the material-mediated healing process

2017

In addition to macrophages, multinucleated giant cells (MNGCs) are involved in the tissue reaction to a variety of biomaterials. Especially in the case of bone substitute materials it has been assumed that the MNGCs are osteoclasts, based on the chemical and physical similarity of many materials to the calcified matrix and the bony environment in which they are used. However, many studies indicate that these cells belong to the cell line of the foreign body giant cells (FBGCs), which are of "inflammatory origin", although they have been shown to possess both a pro- and also anti-inflammatory phenotype. Moreover, no information is available about their role in the tissue reaction to bone sub…

Bioactive and biodegradable silica biomaterial for bone regeneration.

2014

Biosilica, a biocompatible, natural inorganic polymer that is formed by an enzymatic, silicatein-mediated reaction in siliceous sponges to build up their inorganic skeleton, has been shown to be morphogenetically active and to induce mineralization of human osteoblast-like cells (SaOS-2) in vitro. In the present study, we prepared beads (microspheres) by encapsulation of β-tricalcium phosphate [β-TCP], either alone (control) or supplemented with silica or silicatein, into the biodegradable copolymer poly(d,l-lactide-co-glycolide) [PLGA]. Under the conditions used, ≈5% β-TCP, ≈9% silica, and 0.32μg/mg of silicatein were entrapped into the PLGA microspheres (diameter≈800μm). Determination of …

Distribution patterns of neoglycoprotein-binding sites (endogenous lectins) and lectin-reactive glycoconjugates during cartilage and bone formation i…

1995

The distribution of endogenous lectins, visualized by labelled neoglycoproteins, and of defined oligosaccharide structures, reactive with plant lectins, during fetal development of the fingers was analyzed in sections of human 3- to 8-month-old fetal specimens. Chondrogenesis as well as ossification were correlated with characteristic modulations in the expression of both glycoligand-binding molecules and characteristic carbohydrate structures. Occurrence of xylose-specific receptors was judged to be an early sign of cartilage development. Similarly, α-mannosyl residues that had been attached to labelled carrier proteins were strongly bound by the extracellular matrix already during early s…

Thermal increment due to ErCr: YSGG and CO2 laser irradiation of different implant surfaces. A pilot study

2010

Podeu consultar la versió en castellà http://hdl.handle.net/2445/118903

Mesenchymal stem cells derived from inflamed dental pulpal and gingival tissue: a potential application for bone formation

2017

Background Chronic periodontal disease is an infectious disease consisting of prolonged inflammation of the supporting tooth tissue and resulting in bone loss. Guided bone regeneration procedures have become common and safe treatments in dentistry, and in this context dental stem cells would represent the ideal solution as autologous cells. In this study, we verified the ability of dental pulp mesenchymal stem cells (DPSCs) and gingival mesenchymal stem cells (GMSCs) harvested from periodontally affected teeth to produce new mineralized bone tissue in vitro, and compared this to cells from healthy teeth. Methods To characterize DPSCs and GMSCs, we assessed colony-forming assay, immunophenot…

Heterogeneous activation of MMP-9 due to prostate cancer-bone interaction.

2007

OBJECTIVES To determine whether matrix metalloproteinase (MMP)-9 activation resulting from prostate cancer cell-bone interaction is dependent on the tumor cell type and/or the nature of the bone microenvironment. METHODS In vitro co-cultures of human prostate cancer cells (PC3 and C4-2B) and mouse, human fetal, or human adult tissues were performed. In vivo the tumor cells were intratibially injected in SCID mice or intraosseously inoculated into fetal or adult bone xenografts in SCID mice. MMP-2 and MMP-9 expression and activation were determined by gelatin zymography in conditioned media obtained in vitro and in lysates derived from the in vivo studies at different time points. RESULTS Ac…

Addition of blood to a phycogenic bone substitute leads to increased in vivo vascularization

2015

The present study aimed to analyze the effects of the addition of blood to the phycogenic bone substitute Algipore(®) on the severity of in vivo tissue reaction. Initially, Fourier-transform infrared spectroscopy (FTIR) of the bone substitute was conducted to analyze its chemical composition. The subcutaneous implantation model in Balb/c mice was then applied for up to 30 d to analyze the tissue reactions on the basis of specialized histochemical, immunohistochemical, and histomorphometrical methods. The data of the FTIR analysis showed that the phycogenic bone substitute material is mainly composed of hydroxyapatite with some carbonate content. The in vivo analyses revealed that the additi…

Occurrence of bone tissue in the human penis.

1953

?Reliability of new poly (lactic-co-glycolic acid) membranes treated with oxygen plasma plus silicon dioxide layers for pre-prosthetic guided bone re…

2017

Background: The use of cold plasmas may improve the surface roughness of poly(lactic-co-glycolic) acid (PLGA) membranes, which may stimulate the adhesion of osteogenic mediators and cells, thus accelerating the biodegradation of the barriers. Moreover, the incorporation of metallic-oxide particles to the surface of these membranes may enhance their osteoinductive capacity. Therefore, the aim of this paper was to evaluate the reliability of a new PLGA membrane after being treated with oxygen plasma (PO) plus silicon dioxide (SiO) layers for guided bone regeneration (GBR) processes. Material and Methods: Circumferential bone defects (diameter: 11 mm; depth: 3 mm) were created on the top of ei…