scholarly journals Microstructure and Biocompatibility of Hydroxyapatite Porous Ceramics Designed by a Partial Dissolution-Precipitation Technique with Supersonic Treatment for Bone Regeneration

10.5772/32088 ◽  
2012 ◽  
Author(s):  
Toshiyuki Akazawa ◽  
Masaru Murata ◽  
Yasuhiko Tabata ◽  
Manabu Ito
Author(s):  
H. M. Kerch ◽  
R. A. Gerhardt

Highly porous ceramics are employed in a variety of engineering applications due to their unique mechanical, optical, and electrical characteristics. In order to achieve proper design and function, information about the pore structure must be obtained. Parameters of importance include pore size, pore volume, and size distribution, as well as pore texture and geometry. A quantitative determination of these features for high porosity materials by a microscopic technique is usually not done because artifacts introduced by either the sample preparation method or the image forming process of the microscope make interpretation difficult.Scanning electron microscopy for both fractured and polished surfaces has been utilized extensively for examining pore structures. However, there is uncertainty in distinguishing between topography and pores for the fractured specimen and sample pullout obscures the true morphology for samples that are polished. In addition, very small pores (nm range) cannot be resolved in the S.E.M. On the other hand, T.E.M. has better resolution but the specimen preparation methods involved such as powder dispersion, ion milling, and chemical etching may incur problems ranging from preferential widening of pores to partial or complete destruction of the pore network.


2020 ◽  
Vol 48 (3) ◽  
pp. 755-764
Author(s):  
Benjamin B. Rothrauff ◽  
Rocky S. Tuan

Bone possesses an intrinsic regenerative capacity, which can be compromised by aging, disease, trauma, and iatrogenesis (e.g. tumor resection, pharmacological). At present, autografts and allografts are the principal biological treatments available to replace large bone segments, but both entail several limitations that reduce wider use and consistent success. The use of decellularized extracellular matrices (ECM), often derived from xenogeneic sources, has been shown to favorably influence the immune response to injury and promote site-appropriate tissue regeneration. Decellularized bone ECM (dbECM), utilized in several forms — whole organ, particles, hydrogels — has shown promise in both in vitro and in vivo animal studies to promote osteogenic differentiation of stem/progenitor cells and enhance bone regeneration. However, dbECM has yet to be investigated in clinical studies, which are needed to determine the relative efficacy of this emerging biomaterial as compared with established treatments. This mini-review highlights the recent exploration of dbECM as a biomaterial for skeletal tissue engineering and considers modifications on its future use to more consistently promote bone regeneration.


2008 ◽  
Vol 68 (S 01) ◽  
Author(s):  
S Mohr ◽  
BC Portmann-Lanz ◽  
A Schoeberlein ◽  
R Sager ◽  
DV Surbek

1996 ◽  
Vol 76 (01) ◽  
pp. 038-045 ◽  
Author(s):  
Jean-Christophe Gris ◽  
Pierre Toulon ◽  
Sophie Brun ◽  
Claude Maugard ◽  
Christian Sarlat ◽  
...  

SummaryThe high prevalence of free protein S deficiency in human immunodeficiency virus (HlV)-infected patients is poorly understood. We studied 38 HIV seropositive patients. Free protein S antigen values assayed using the polyethylene-glycol precipitation technique (PEG-fS) were statistically lower in patients than in controls. These values using a specific monoclonal antibody-based ELISA (MoAb-fS) and the values of protein S activity (S-act) were not statistically different between patients and controls. C4b-binding protein values were not different from control values. In patients, PEG-fS values were lower than MoAb-fS values. Ten patients had a PEG-fS deficiency, 4 patients had a MoAb-fS deficiency and 8 had a S-act deficiency. Protein S activity and MoAb-fS were lower in clinical groups with poor prognosis and in patients with AIDS but PEG-fS was not. A trend for reduced S-act/MoAb-fS ratios was observed in patients. PEG-fS was negatively correlated with anticardiolipin antibody titers whereas MoAb-fS was not. The plasma of PEG-fS deficient HIV-patients contained high amounts of flow cytometry detectable microparticles which were depleted from plasma by PEG precipitation. The microparticles were partly CD42b and CD4 positive but CD8 negative. These microparticles were labelled by an anti free protein S monoclonal antibody. The observed differences between MoAb-fS and PEG-fS values were correlated with the amount of detectable plasma microparticles, just like the differences between MoAb-fS and S-act. Plasma microparticles correlated with anticardiolipin antibody titers.In summary, free protein S antigen in HIV infected patients is underestimated when the PEG precipitation technique is used due to the presence of elevated levels of microparticles that bind protein S. The activity of free protein S is also impaired by high levels of microparticles. The prevalence of free protein S deficiency in HIV positive patients is lower than previously published (4/38, -10%) and is correlated with poor prognosis. By implication, use of a PEG precipitation technique might give artefactually low free protein S antigen values in other patient groups if high numbers of microparticles are present. In HIV patients, high titers of anticardiolipin antibodies are associated with high concentrations of cell-derived plasma microparticles.


2016 ◽  
Author(s):  
Carina Kampleitner ◽  
Gerhard Hildebrand ◽  
Klaus Liefeith ◽  
Constancio Gonzalez ◽  
Jose Carlos Rodriguez-Cabello ◽  
...  
Keyword(s):  

Author(s):  
Saurabh Mohan Kamat ◽  
Rakshit Khandeparker ◽  
Francis Akkara ◽  
Vikas Dhupar ◽  
Ashwin Mysore

Membrane fixation in guided bone regeneration (GBR) has been traditionally achieved using resorbable pins, titanium tacks or miniscrews. However, these techniques are marredwith a number of clinical challenges. This article presents the “SauFRa” technique, a novel technique for stabilization of resorbable membranes in both, single as well as multiple implant sites while avoiding the shortcomings of other suturing techniques described in literature. Furthermore, the technique also eliminates the possibility of complications observed when using resorbable pins, titanium tacks or miniscrews, such as damage to adjacent roots during insertion. The authors’ employed this technique in 89 patients (51 male and 35 female) and found no complications like tissue dehiscence, infection or graft migration.


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