No abstract

No abstract

Collagenated porcine-derived bone graft materials exhibit osteoconductive properties and the development of different formulations intends to enhance bone regeneration. This study aims to evaluate bone healing in a rabbit cancellous bone defect in response to grafting with different physicochemical forms of heterologous porcine bone. Twenty-six adult male New Zealand White rabbits received two critical size femoral bone defects per animal (n = 52), each randomly assigned to one of the five tested materials (Apatos, Gen-Os, mp3, Putty, and Gel 40). Animals were sacrificed at 15- and 30-days post-surgery. Qualitative and quantitative (new bone, particle and connective tissue percentages) histological analyses were performed. Histomorphometry showed statistically significant differences in all evaluated parameters between mp3 and both Putty and Gel 40 groups, regardless of the timepoint (p < 0.05). Moreover, statistical differences were observed between Apatos and both Putty (p = 0.014) and Gel 40 (p = 0.007) groups, at 30 days, in regard to particle percentage. Within each group, regarding new bone formation, mp3 showed significant differences (p = 0.028) between 15 (40.93 ± 3.49%) and 30 (52.49 ± 11.04%) days. Additionally, intragroup analysis concerning the percentage of particles revealed a significant reduction in particle occupied area from 15 to 30 days in mp3 and Gen-Os groups (p = 0.009). All mp3, Gen-Os and Apatos exhibited promising results in terms of new bone formation, thus presenting suitable alternatives to be used in bone regeneration.

The method we have applied to visualize the elastic fibres of the lung is a unique approach to define the spatial organization of the pulmonary elastic fibres. We have demonstrated here the close relationship between the elastic fibres and the capillaries of the septal alveoli. The arrangement of the interwoven network of elastin and its relationship with the capillaries offers the structural setting for the distending capacity of the alveolar wall.

Morselized bone allografts have been used for the treatment of bone stock loss in orthopedic revision surgery with encouraging results. However, several parameters can influence the graft incorporation including the processing treatments. This experimental work used a cavitary bone defect in 90 rabbits to evaluate the sequence of incorporation of three different kinds of morselized bone allografts: uncryopreserved cancellous bone, freeze-dried cancellous bone, and totally demineralized cortical bone each of which were prepared in accordance with our rigid protocol. Revascularization and remodeling of the transplanted bone grafts were evident upon histological evaluation. Bone apposition and bone resorption resulted in a mixture of graft and new bone. Mineralized cancellous grafts showed great osteoconductive capacity, whereas demineralized cortical grafts showed an intense osteoinductive capacity and a weak osteoconductive capacity. In a general evaluation, cryopreserved cancellous bone grafts showed superior biological efficacy for reconstruction of experimental bone defects, closely followed by freeze-dried cancellous bone grafts, and, finally, by demineralized cortical bone grafts. These results validate our protocol for the processing and preservation of these three kinds of bone grafts. B ONE STOCK LOSS is the main problem for revision surgery of a failed total hip prosthesis. In our institution, impacted morselized bone allografts are frequently used in conjunction with a roof reinforcement ring for acetabular reconstruction and a cementless stem on the femoral side, even in large cavitary defects. Initially, these defects were filled with bone cement but it soon became clear that the failure rate of this technique was unacceptably high. Although the reconstruction of the osteolyses induced by aseptic loosening of hip prosthesis with impacted morselized cancellous allografts had demonstrated satisfactory results, 1-4 controversy still exists about the best approach to these bone stock deficiencies. It is recognized that, in addition to the surgical technique, the methods of bone allograft processing, preservation, and sterilization can alter both its initial physical and chemical properties and their immune response, as well as endanger the mechanical stability of the surgical reconstruction, 5 concomitantly influencing the biological behavior of the allografts.This study evaluated the incorporation sequence of three different kinds of morselized bone allografts-cryopreserved cancellous bone, freeze-dried cancellous bone, and totally demineralized cortical bone-prepared in accordance with our current protocol. An experimental model was developed using a cavitary bone defect in rabbits. The impacted bone allografts were placed into the cancellous bone of the rabbit knee under mechanical stability conditions. MATERIALS AND METHODS Preparation of Graft MaterialAll bone grafts were harvested from donor Californian rabbits using standard aseptic techniques. The cancellous bone was harvested from the fem...