Papers by Keyword: Animal Model

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Authors: M.T. Oliveira, S. Lucena, J. Potes, M.C. Queiroga, S. Rehman, K. Dalgarno, A. Ramos, J.C. Reis
Abstract: The testing of novel biomaterials for percutaneous vertebroplasty depends on suitable animal models. The aim of this study was to develop ex vivo a reproducible and feasible model of percutaneous vertebroplasty, for ulterior application in vivo. A large animal model was used (Merino sheep), due to its translational properties. Vertebroplasty was performed under tactile and fluoroscopic control, through a bilateral modified parapedicular access in lumbar vertebrae (n=12). Care was taken in order to avoid disruption of the vertebral foramen. The average defect volume was 1234±240 mm3. This mean volume ensures practical defects to test novel injectable biomaterials. 6 vertebrae were injected with a commercial cement (Cerament®, Bone Support, Sweden). Adequate defect filling was observed in all vertebrae. All vertebrae were assessed by microCT, prior to and post defect creation and after biomaterial injection. All vertebrae were mechanical tested. No mechanical failure was observed under loads higher than the physiological. Ultimately, this model is considered suitable for pre-clinical in vivo studies, mimicking clinical application.
Authors: Yang Bai, Na Liu, Jian Feng Chen, Li Sheng Zhao, Bin Deng, Ning Wen, Hong Chen Liu
Abstract: Objective: To compare the effectiveness of different proportional nHA / PLA application in alveolar bone preservation. Methods: After extraction, apply extraction socket filling based on the alveolar bone defect model due to absorption in Beagle dog. Implant materials are divided into 3 different groups: nHA / PLAI, nHA / PLAII and the control group. Samples of the alveolar bone were collected at Week 4 and 8, respectively for the bone resorption assessment, bone density measurement, and histological examination. Results: After nHA / PLA implantation, the alveolar bone preservation was significantly improved. There was no difference in the alveolar bone preservation between the nHA / PLAI and nHA / PLAII groups. However, the sample which are 8w from group I, have higher bone density and have complete absorption in their dental material nest .Therefore group I is better than group II. Conclusions: The results can provide a reliable basis for the application of alveolar bone preservation in basic research and selection of clinical materials.
Authors: Simona Cavalu, Viorica Simon, Cristian Ratiu, Ioan George Oswald, Vlad Silviu, Oana Ponta
Abstract: This study presents some aspects regarding the evaluation of bone-implant interactions using two animal models (rabbit and rat). The proposed implants are new alumina/zirconia bioceramics designed for hard tissue replacement (oral implantology or arthroplasty). The animal selection was made based on the number and size or design of implants to be tested as these factors influence directly the species of animal chosen for this study. The correct placement and stability of the implants were evaluated by radiographic images. SEM micrographs were recorded on the bone/implant area along with the elemental composition of the sheared implant surfaces at different time intervals after the surgery. Calcium/phosphate ratio was considered as an indicative of the surface implant coverage for a successful osseointegration. Histological examination of the bone and bone marrow in direct contact with the implants was performed to detect any immunological or inflammatory responses. Each of the animal species (rat or rabbit) demonstrated unique advantages and disadvantages as a model for demonstrating the response of bone tissue to an implant material. The size and design of the implants also influenced the bone turnover as demonstrated histologically.
Authors: J.V. Lobato, Nandyala Sooraj Hussain, C.M. Botelho, J.M. Rodrigues, A.L. Luís, Ana Colette Maurício, M.A. Lopes, José D. Santos
Abstract: BonelikeÒ graft that mimics the inorganic composition of bone tissue has been developed and characterized over the last decade. To evaluate the osteoconductivity of BonelikeÒ two granule size ranges, one ranging from 150-250µm and the other from 250-500µm were implanted in the femurs of New Zealand White rabbits, aiming at being clinically used in different medical applications, such as dentistry and orthopaedics. In order to facilitate the medical application of the BonelikeÒ graft the use of a commercially available polymeric vehicle was also analyzed. Radiological examination, histological studies and scanning electron microscopy (SEM) analyses revealed that the surface of Bonelike® granules was almost completely surrounded by new bone formation after 12 weeks of implantation, which proves its highly osteoconductive behaviour.
Authors: Takashi Nakamura, Hirofumi Kato, Y. Okada, S. Shinzato, Keiichi Kawanabe, Jiro Tamura, Tadashi Kokubo
Authors: Stefano D'Adamio, G. Maccauro, Giuseppe Malerba, Corrado Piconi
Abstract: Prosthetic loosening in absence of infection (aseptic loosening) is the most common reason for revision of Total Hip Replacements (THR) Alumina and/or zirconia-based ceramic materials generally displayed high wear resistance and are considered suitable for load bearing application. To characterize the possible chronic cellular reactions to ceramic debris is then relevant in view of their long-term implantation. Low density ceramic pellets obtained by alumina and zirconia (Y-TZP) medical-grade precursors, were sintered at intermediate density and implanted in the patellar tendon of 24 NZW adult rabbits (group A). In this way the progressive release into the joint space of grains detached from surface of the pellets by the motion of the joint. Other 24 NZW rabbits (group B) received 5mg of powders injected in the articular capsule. Animals were killed at different intervals (1,3,6,12 months). Retrieved knee joints underwent X-Ray, histological and ultrastructural analysis. Peripheral organs (liver, kidney, lung, spleen, brain) were collected at same time. For, histologic analysis of tissue specimens collected in revision surgeries were fixed in 10% formalin, then decalcified ethylendiamintetracetic acid (EDTA), dehydrated and embedded in paraffin, sectioned and stained with hematoxylin-eosin. Histologic reaction was similar for the two ceramics and independent of the physical form (powders or pellets). Ceramic particulate was observed in the periprosthetic tissue membrane, the smaller inside mononuclear histiocyte-like cells in granuloma-like tissue, while the largest were in a synovial-like membrane inside a stroma poor in vessel containing mononuclear cells and rarely giant cells. No toxic nor carcinogenic effects were observed in peripheral organs retrieved at different time intervals. Although the ankyloses of the joints is a limiting factor for the duration of the test, this method may be a useful tool to evaluate the reactions to wear debris, and may result suitable also to evaluate the chronic response to metals or polymers of clinical interest.
Authors: Keon Hyeon Jo, Seok Whan Moon, Young Du Kim, Young Jo Sa, Si Young Choi, Jeong Sub Yoon, Young Pil Wang, Guw Dong Yeo, Cheol Min Bae
Abstract: To prevent prolonged air leakage after lung surgery, we developed a biodegradable polyglycolic acid (PGA) sheet and compared it with an expanded polytetrafluoethylene (ePTFE). Eighteen adult mongrel dogs were used in this experiment. The airway pressures at which air first leaked at the stapled resection margins were measured immediately after surgery in group I (N=5), 2 days after surgery in group II (N=5), and 7 days after surgery in group IIII (N=5), Based on the presence of SLR, there were 3 subgroups in each group: there was no SLR in subgroup a; ePTFE in subgroup b; PGA sheet in subgroup c. The histologic examination was performed 2 months after surgery (N=3). In group I, there was a significant difference in air leakage pressures (mm Hg) between no reinforcement and SLR. We observed the same results in group II and III with statistical significance. However, there was no significant difference between the reinforcement groups. The histologic findings demonstrated more severe adhesions and biodegradation in the dogs in which the PGA sheet was used. Our PGA sheet was considered a useful reinforcement material, because it had a similar threshold for air leakage with the ePTFE with excellent biodegradation.
Authors: G. Daculsi, Daniel Chappard, Eric Aguado, G. Legeay, Pierre Layrolle, Pierre Weiss
Abstract: This paper reports on the research into multiphase bone substitutes carried out by laboratories from the ‘Pays de la Loire’ region in France. This collaborative research was funded by both the French Government and the Regional Council in the period 2000-2007. Calcium phosphate bioceramics, polymers and combinations have been developed as bone substitutes for various maxillofacial and orthopaedic applications. These bone substitutes should support and regenerate bone tissue and resorb after implantation. In the bone tissue engineering area, they have been combined with autologous bone marrow cells or bioactive factors. The bone substitutes were tested in various animal models mimicking clinical situations or under pathological conditions (osteoporosis). In order to complete our research, the multiphase materials were also evaluated in clinical trials.
Authors: Tetsuya Abe, Masataka Sakane, Toshiyuki Ikoma, Toru Tonegawa, Tomonori Yoshioka, M. Tanaka, Naoyuki Ochiai
Abstract: The extent of osseous involvement, particularly spinal cord compression, is directly correlated with patient survival. To treat metastatic spine cancer, we have developed novel paclitaxel-loaded hydroxyapatite-alginate gels. In this study, an intraosseous spinal cancer model in rats was used to investigate the efficacy of local treatment. Ten rats were randomized into two groups, a local treatment group and a control group. Disease-free time and survival rate in the local treatment group were significantly longer in this model. (p<0.05)
Authors: G. Daculsi, P. Corre, Oliver Malard, Racquel Z. LeGeros, Eric Goyenvalle
Abstract: Calcium phosphate bioceramics and bovine bone xenograft with or without sintering are more or less used in orthopaedics or in maxillofacial surgery. In this study we compare in a rat femoral epiphysis model after 3 weeks of implantation the bone in growth at the expense of granules of same size of micro macro porous biphasic calcium phosphate MBCP, sintered bovine bone and unsintered BioOss.
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