Browsing by Subject "Bone"

Now showing 1 - 6 of 6
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    Advances in 3D bioprinting to enhance translational applications in bone tissue engineering and regenerative medicin
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2025) Ortega, Miguel A; Leon Oliva, Diego De; Liviu Boaru, Diego; Fraile-Martínez, Oscar; Garcia Montero, Cielo; Casanova, Carlos; García Honduvilla, Natalio; Buján, Julia; Saez, Miguel A; Álvarez Mon, Melchor; Velazquez De Castro, Amador; López González, Laura; Acero, Julio; Barrena Blázquez, Silvestra; Diaz, Raul
    Bone defects are due to trauma, infections, tumors, or aging, including bone fractures, bone metastases, osteoporosis, or osteoarthritis. The global burden of these demands research into innovative strategies that overcome the limitations of conventional autografts. In this sense, the development of three-dimensional (3D) bioprinting has emerged as a promising approach in the field of tissue engineering and regenerative medicine (TERM) for the on-demand generation and transplantation of tissues and organs, including bone. It combines biological materials and living cells, which are precisely positioned layer by layer. Despite obtaining some promising results, 3D bioprinting of bone tissue still faces several challenges, such as generating an effective vascular network to increase tissue viability. In this review, we aim to collect the main knowledge on methods and techniques of 3D bioprinting. Then, we will review the main biomaterials, their composition, and the rationale for their application in 3D bioprinting for the TERM of bone.
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    Changes in bone mineralization pattern, a response to local stimulus in maxilla and mandible of dogs
    (Murcia : F. Hernández, 1988) Buchanan, Mary; Sandhu, H.S.; Anderson, Colin
    A pilot study was carried out in order to verify the pattern of changes in mineralization of bone in the maxillas and mandibles of dogs which had a tooth extraction or luxation. Bone mineral content was determined using computerized microdensitometry. Significant changes in patterns of mineralization were found for alveolar bone, cortical bone and trabecular bone at the sites adjacent to the area of operation. These findings suggest that the three envelopes of jaw bones of the dogs are influenced by Regional activation phenomenon (RAP). These results have important implications for the design of clinical studies of periodontium. A more detailed study should elucidate the cellular mechanisms by which these changes occur.
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    Quantification of nitrogenous bases, DNA and Collagen type I for the estimation of the postmortem interval in bone remains
    (2017-11-04) Pérez Martínez, Cristina; Pérez Cárceles, María Dolores; Legaz Pérez, Isabel; Prieto Bonete, Gemma; Luna, Aurelio; Ciencias Sociosanitarias
    Estimating the postmortem interval (PMI) is an important goal in forensic medicine and continues to be one of the most difficult tasks of the forensic investigator. Few accurate methods exist to determine the time since death of skeletonized human remains due to the great number of intrinsic and external factors that may alter the normal course of postmortem change. The purpose of this research was to assess the usefulness of various biochemical parameters, such as nitrogenous bases (adenine, guanine, purines, cytosine, thymine, pyrimidines, hypoxanthine and xanthine), DNA and Collagen Type I peptides to estimate PMI. These parameters were analysed in cortical bone for the establishment of data in a total of 80 long bones of 80 corpses (50 males, 30 females) with a mean age of 68.31 years (S.D. = 18.021, range = 20–97). The bones were removed from the cement niches of a cemetery in Murcia (south-eastern Spain), where they had lain for between 5 and 47 years (mean time 23.83 years, S.D. = 10.85). Our results show a significant decrease in adenine (p = 0.0004), guanine (p = 0.0001), purines (p = 0.0001), cytosine (p = 0.0001), thymine (p = 0.0226), pyrimidines (p = 0.0002) and the number of peptides of Collagen type I (p = 0.0053) in those with a PMI ≥ 20 years. In a curvilinear regression analysis the results show that 30.6% of the variable PMI could be explained by guanine concentration, in bones with a PMI < 20 years, while in cases of a PMI ≥ 20 years, the variable that best explained membership of this group was adenine (38.0%). In the discriminant analysis applied to the all the variables as a function of PMI when two groups were established, 86.7% of the cases were correctly classified. These results show that the quantification of Collagen type I proteins and nitrogenous bases could be used as a complementary tool, together with other analyses, in the estimation of PMI.
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    RANKL is downregulated in bone cells by physical activity (treadmill and vibration stimulation training) in rat with glucocorticoid-induced osteoporosis
    (F. Hernández y Juan F. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología, 2013) Pichler, Karin; Loreto, Carla; Leonardi, Rosalia; Reuber, Tobias; Weinberg, Annelie Martina; Musumeci, Giuseppe
    The aim of this study was to investigate bone tissue and plasma levels of RANKL and OPG in rats with prednisolone-induced osteoporosis and to evaluate the outcomes of physical activity on the skeletal system by treadmill and vibration platform training. Osteoporosis is a disease characterised by low bone mass and structural deterioration of bone tissue leading to bone fragility. Vibration exercise is a new and effective measure to prevent muscular atrophy and osteoporosis. The animals were divided into 5 groups. 1: control rats; 2: rats with osteoporosis receiving prednisolone; 3: rats receiving prednisolone and treadmill training; 4: rats receiving prednisolone and vibration stimulation training; 5: rats receiving prednisolone, treadmill and vibration stimulation training. For bone evaluations we used whole-body scans, histology and histomorphometric analysis. RANKL and OPG expression was evaluated by immunohistochemistry and biochemical analysis. After treatment, our data demonstrated that RANKL expression was significantly increased in groups 2 and 3 and decreased in groups 4 and 5. Conversely, OPG expression was significantly decreased in groups 2 and 3 and increased in groups 4 and 5. In conclusion, our findings suggest that mechanical stimulation inhibits the activity of RANKL. This finding provides new insights into the occurrence and progression of osteoporosis.
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    Regulated expression of MCP-I by osteoblastic cells in vitro and in vivo
    (Murcia : F. Hernández, 1999) Graves, D.T.; Jiang, Y.; Valente, A.J.
    Inflammation is characterized by the recruitment of leukocytes from the vasculature. Recent studies have implicated chemokines as an important class of mediators that function principally to stimulate leukocyte recruitment, and in some cases, leukocyte activity. There are four defined chemokine subfamilies based on their primary structure, CXC, CC, C and CX3C. Members of the CC chemokine subfamily, such as monocyte chemoattractant protein 1 (MCP-l), are chemotactic for monocytes and other leukocyte subsets. The studies described below focus on the expression of MCP-1 in vitro and in vivo in an osseous environment. These studies indicate that MCP-1 is typically not expressed in normal bone or by normal osteoblasts in vitro. Upon stimulation by inflammatory mediators, MCP-1 is up-regulated. This expression is temporally and spatially associated with the recruitment of monocytes in both osseous inflammation and during developmentally regulated bone remodelling. Furthermore, exogenous MCP-1 applied to inflamed bone enhances the recruitment of monocytes. Because monocytes produce factors that influence osseous metabolism, including but not limited to prostglandins, platelet-derived growth factor, interleukin-l or tumor necrosis factor, chemokines that initiate their recruitment are likely to be highly important.
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    The history and histology of bone morphogenetic protein
    (2016) Murray, Samuel S.; Brochmann Murray, Elsa J. B; Wang, Jeffrey C.; Leite Duarte, Maria Eugenia
    Bone morphogenetic proteins are a group of structurally related proteins within the TGF-β superfamily of proteins with a diverse repertoire of functions in embryonic and adult organisms. As is apparent from the name, the members first characterized participate in bone growth, development, and remodeling. The “morphogenic” activity per se is defined as the induction of a recapitulation of endochondral bone formation by appropriate stem cells. The regenerative capacity of bone has been recognized since ancient times. The mechanism, applications, and conceptual basis of bone transplantation, bone implantation, ectopic bone formation, and exogenously induced bone formation have been studied by many investigators for more than a century. This review examines the efforts to characterize this activity in the European and American literature over approximately the last century. Because of the inherently complex nature of the process induced by these molecules (inflammation, stem cell proliferation, cartilage differentiation, replacement of cartilage with bone) it is important to evaluate previous investigations through a histological perspective. The cellular basis of the contemporary bioassay for BMP activity is illustrated and discussed from the histological point of view.