The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
P. Bonnevialle - One of the best experts on this subject based on the ideXlab platform.
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Bone cell grafts in bioreactor: a study of feasibility of bone cell autograft in large defects
Journal of Materials Science: Materials in Medicine, 1991Co-Authors: P. Frayssinet, I. Primout, N. Rouquet, A. Autefage, A. Guilhem, P. BonnevialleAbstract:Cancellous bone cells were isolated from adult dogs, introduced into cell culture, subcultured and grown on Hydroxylapatite granules. Cells immobilized on these granules were used to make bioreactors which were implanted in dog ulna diaphyse to fill osseous defects. The bioreactor implantation constituted a bone cell autograft and showed bone formation in a reactor containing cultured cells but not in the control reactor containing Hydroxylapatite granules without cells. These results indicate that Hydroxylapatite material can be used in bioartificial organs. The properties of Hydroxylapatite used in bone reconstruction are due to the cells and extra-cellular matrix immobilized on its surface.
Tsutomu Furuzono - One of the best experts on this subject based on the ideXlab platform.
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Hydroxylapatite nanoparticles fabrication methods and medical applications
Science and Technology of Advanced Materials, 2012Co-Authors: Masahiro Okada, Tsutomu FuruzonoAbstract:Hydroxylapatite (or hydroxyapatite, HAp) exhibits excellent biocompatibility with various kinds of cells and tissues, making it an ideal candidate for tissue engineering, orthopedic and dental applications. Nanosized materials offer improved performances compared with conventional materials due to their large surface-to-volume ratios. This review summarizes existing knowledge and recent progress in fabrication methods of nanosized (or nanostructured) HAp particles, as well as their recent applications in medical and dental fields. In section 1, we provide a brief overview of HAp and nanoparticles. In section 2, fabrication methods of HAp nanoparticles are described based on the particle formation mechanisms. Recent applications of HAp nanoparticles are summarized in section 3. The future perspectives in this active research area are given in section 4.
Brian L Mcintyre - One of the best experts on this subject based on the ideXlab platform.
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a 1 year study of osteoinduction in hydroxyapatite derived biomaterials in an adult sheep model part ii bioengineering implants to optimize bone replacement in reconstruction of cranial defects
Plastic and Reconstructive Surgery, 2004Co-Authors: Arun K Gosain, Paul A Riordan, Liansheng Song, Marco T J Amarante, Behrooz Kalantarian, Paul G Nagy, Charles R Wilson, Jeffrey M Toth, Brian L McintyreAbstract:The present study investigated hydroxyapatite biomaterials implanted in critical-size defects in the calvaria of adult sheep to determine the optimal bioengineering of hydroxyapatite composites to facilitate bone ingrowth into these materials. Five calvarial defects measuring 16.8 mm in diameter were made in each of 10 adult sheep. Three defects were filled with cement paste composites of hydroxyapatite and β-tricalcium phosphate as follows: (1) 100 percent hydroxyapatite-cement paste, (2) 60 percent hydroxyapatite-cement paste, and (3) 20 percent hydroxyapatite-cement paste. One defect was filled with a ceramic composite containing 60 percent hydroxyapatite-ceramic, and the fifth defect remained unfilled. One year after implantation, the volume of all biomaterials was determined by computed tomography, and porosity and bone replacement were determined using backscatter electron microscopy. Computed tomography-based volumetric assessment 1 year after implantation demonstrated that none of the unfilled cranial defects closed over the 1-year period, confirming that these were critical-size defects. There was a significant increase in volume in both the cement paste and ceramic implants containing 60 percent hydroxyapatite (p < 0.01). There was no significant change in volume of the remaining cement paste biomaterials. Analysis of specimens by backscatter electron microscopy demonstrated mean bone replacement of 4.8 ± 1.4 percent (mean ± SEM) in 100 percent hydroxyapatite-cement paste, 11.2 ± 2.3 percent in 60 percent hydroxyapatite-cement paste, and 28.5 ± 4.5 percent in 20 percent hydroxyapatite-cement paste. There was an inverse correlation between the concentration of hydroxyapatite and the amount of bone replacement in the cement paste for each composite tested (p < 0.01). Bone replacement in 60 percent hydroxyapatite-ceramic composite (13.6 ± 2.0 percent) was not significantly different from that in 60 percent hydroxyapatite-cement paste. Of note is that the ceramic composite contained macropores (200 to 300 μm) that did not change in size over the 1-year period. All cement paste composites initially contained micropores (3 to 5 nm), which remained unchanged in 100 percent hydroxyapatite-cement paste. Cement paste implants containing increased tricalcium phosphate demonstrated a corresponding increase in macropores following resorption of the tricalcium phosphate component. Bone replacement occurred within the macropores of these implants. In conclusion, there was no significant bone ingrowth into pure hydroxyapatite-cement paste (Bone Source, Stryker-Leibinger Inc., Dallas, Texas) in the present study. The introduction of macropores in a biomaterial can optimize bone ingrowth for reconstruction of critical-size defects in calvaria. This was demonstrated in both the ceramic composite of hydroxyapatite tested and the cement paste composites of hydroxyapatite by increasing the composition of a rapidly resorbing component such as β-tri-calcium phosphate.
Robert A. Goldenberg - One of the best experts on this subject based on the ideXlab platform.
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Hydroxylapatite ossicular replacement prostheses: Results in 157 consecutive cases
Laryngoscope, 1992Co-Authors: Robert A. GoldenbergAbstract:The use of Hydroxylapatite for ossicular chain reconstruction is increasing. In this study, hearing results and extrusion rate for 157 consecutive patients receiving Hydroxylapatite prostheses were evaluated. Results were compared to those of a control group of patients who had received either homograft bone or Plasti-Pore prostheses. Four (2.6%) cases of extrusion have occurred. Hearing success was defined as a postoperative puretone average air-bone gap of < or = 15 dB for incus prostheses and partial ossicular replacement prostheses (PORPs) or < or = 25 dB for incus-stapes prostheses and total ossicular reconstruction prostheses (TORPs). Overall success rate in the Hydroxylapatite group was 51.4% for the 140 patients with postoperative data (mean follow-up, 11.5 months) and 46.7% for 90 patients who were followed for more than 6 months (mean follow-up, 16 months). PORP results were significantly poorer than those of the other prostheses. The success rate for the control group was 58.6% for 58 patients. The difference between Hydroxylapatite and control group success rates appears to be due to the poorer results of the Hydroxylapatite PORP.
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Hydroxylapatite ossicular replacement prostheses: a four-year experience.
Otolaryngology-Head and Neck Surgery, 1992Co-Authors: Robert A. GoldenbergAbstract:Between 1987 and 1991, I have used 215 Hydroxylapatite middle ear implants, in various styles, for hearing reconstruction. The first such implants were composed entirely of Hydroxylapatite. Because of intraoperative difficulties in shaping and trimming these prostheses, hybrid prostheses using Plasti-Pore were developed. For each of four implant designs (incus, incus-stapes, PORP, and TORP), the head is constructed from Hydroxylapatite and the shaft from Plasti-Pore. Extrusion rate for the hybrid prostheses is low (4.3%). Hearing results from 47 patients with the hybrid Hydroxylapatite prostheses, 140 patients with total Hydroxylapatite prostheses, and 75 control group patients with homograft bone or Plasti-Pore prostheses were compared. A "successful" hearing result was achieved in 51.1%, 51.4%, and 60.0% of the three groups, respectively. Surgical technique for use of the new hybrid Hydroxylapatite prostheses is described.
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Hydroxylapatite ossicular replacement prostheses: preliminary results.
Laryngoscope, 1990Co-Authors: Robert A. GoldenbergAbstract:Hearing results and extrusion rate for 89 consecutive patients receiving Hydroxylapatite prostheses for hearing reconstruction were evaluated and compared to a control group of 75 patients who had received homograft bone or Plasti-Pore prostheses. At the 3-month follow-up, there were no cases of extrusion of the Hydroxylapatite prostheses. Hearing success was defined as a postoperative air-bone gap of less than or equal to 15 dB for incus prostheses and partial ossicular replacement prostheses or less than or equal to 25 dB for incus-stapes prostheses and total ossicular replacement prostheses. There was a statistically significant difference in the distribution-of-success rate by prosthesis type for the Hydroxylapatite. Incus, incus-stapes, and total ossicular replacement prosthesis results were similar, but partial ossicular replacement prosthesis results were poorer. The overall success rate in the Hydroxylapatite group was 51.2%; in the control group, it was 60%. Hearing results tended to be better with the Hydroxylapatite incus prosthesis than with the homograft bone incus, but poorer with the Hydroxylapatite partial ossicular replacement prosthesis than with the Plasti-Pore. Several technical modifications of the prosthesis that may improve results with the Hydroxylapatite partial ossicular replacement prosthesis are suggested. Hydroxylapatite middle ear prostheses appear to be a reasonable alternative to other more commonly used prostheses, which carry disadvantages related to the use of human tissue.
P. Frayssinet - One of the best experts on this subject based on the ideXlab platform.
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Bone cell grafts in bioreactor: a study of feasibility of bone cell autograft in large defects
Journal of Materials Science: Materials in Medicine, 1991Co-Authors: P. Frayssinet, I. Primout, N. Rouquet, A. Autefage, A. Guilhem, P. BonnevialleAbstract:Cancellous bone cells were isolated from adult dogs, introduced into cell culture, subcultured and grown on Hydroxylapatite granules. Cells immobilized on these granules were used to make bioreactors which were implanted in dog ulna diaphyse to fill osseous defects. The bioreactor implantation constituted a bone cell autograft and showed bone formation in a reactor containing cultured cells but not in the control reactor containing Hydroxylapatite granules without cells. These results indicate that Hydroxylapatite material can be used in bioartificial organs. The properties of Hydroxylapatite used in bone reconstruction are due to the cells and extra-cellular matrix immobilized on its surface.
