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Biocompatibility of Powdered Materials: The Influence of Surface Characteristics
Published in Michel Nardin, Eugène Papirer, Powders and Fibers, 2006
Patrick Frayssinet, Patrice Laquerriere
The macrophage is a cell able to internalize the particles by phagocytosis in special internal compartments in order to destroy them by physico-chemical mechanisms (Figure 12.2 and Figure 12.3). Phagocytosis is the ingestion of large particles, minerals, microorganisms, or dead cells in large vesicles called phagosomes. These cells can also fuse to form multinucleated giant cells. Interleukin-4 (IL-4) is able to induce foreign body giant cells from human monocytes and macrophages.2 This effect is optimized with granulocyte macrophage–colony stimulating factor (GM–CSF) or IL-3 (Interleukin-3), dependent on the concentration of IL-4.
Introduction to Noninvasive Therapies
Published in Robert B. Northrop, Non-Invasive Instrumentation and Measurement in Medical Diagnosis, 2017
Osteoclasts are a type of multinucleated bone cell that has the function of resorbing bone tissue. Immune system macrophages are transformed into osteoclasts through the action of receptor activator of nuclear factor κβ ligand (RANKL) and macrophage colony-stimulating factor (M-CSF). These hormones are produced by neighboring stromal cells and osteoblasts; this requires direct contact between these cells and osteoclast precursors. Osteoclasts are regulated by several hormones, including PTH and interleukin-6 (IL-6) (Northrop and Connor 2009, Table 7.1). Osteoblasts secrete IL-6.
Effect of Process Parameters on Cutting Forces and Osteonecrosis for Orthopedic Bone Drilling Applications
Published in Chander Prakash, Sunpreet Singh, J. Paulo Davim, Characterization, Testing, Measurement, and Metrology, 2020
Atul Babbar, Vivek Jain, Dheeraj Gupta, Chander Prakash, Sunpreet Singh, Ankit Sharma
Osteoclasts: These are the “destructor” of bones. These are very large multinucleate cells responsible for the resorption of bones. These are the cells with multiple nuclei located on bone surfaces in resorption pits called Howships lacunae.
The opportunity of using alloplastic bone augmentation materials in the maxillofacial region– Literature review
Published in Particulate Science and Technology, 2019
Simion Bran, Grigore Baciut, Mihaela Baciut, Ileana Mitre, Florin Onisor, Mihaela Hedesiu, Avram Manea
Osteoclasts are multinucleated cells that play the main role in bone resorption. They are only cells that destroy and resorb bone. Abnormal increase in osteoclast function leads to bone diseases such as osteoporosis (where resorption exceeds formation decreasing bone density and increasing fracture rate). In other pathologic conditions (e.g., bone metastases and inflammatory arthritis) abnormal osteoclast activity results in periarticular erosions and painful osteolytic lesions (Hellstein et al. 2011). This imbalance between resorption and formation of the bone is frequently treated with drugs called bisphosphonates which decrease osteoclast activity. Although their benefits considerably outweigh the risks, one side effect must be noted: the risk of BRONJ (Bisphosphonate-Related Osteonecrosis of the Jaw). This is why, the practitioner that performs any type of bone surgery must be aware of present bisphosphonate therapy and even distant history of such treatment (Charles and Aliprantis 2014).
The application of nanogenerators and piezoelectricity in osteogenesis
Published in Science and Technology of Advanced Materials, 2019
Fu-Cheng Kao, Ping-Yeh Chiu, Tsung-Ting Tsai, Zong-Hong Lin
Bone is a rigid organ that supports and protects various parts of the body. It is highly hierarchical in structure and composed of an extracellular matrix and cellular components: osteoblasts, osteoclasts, osteocytes and bone marrow cells (including hematopoietic cells). The extracellular matrix consists of 65% mineral matrix and 35% organic matrix [4]. Type I collagen makes up about 90% of the organic matrix and possesses a triple helical structure that contributes tensile strength to the extracellular matrix. Inorganic minerals, which are responsible for the compressive strength of bone, are incorporated with the collagen fibrils in the form of calcium hydroxyapatite [5]. Osteoblasts arise from mesenchymal stem cells and are responsible for bone formation. On the other hand, osteoclasts are multinucleated cells deriving from hematopoietic progenitors in the bone marrow and are responsible for bone resorption. Osteocytes are thought to be mechanosensor cells that control the activity of osteoblasts and osteoclasts. They are embedded in lacunae with long processes located in small channels called canaliculi. Canaliculi are considered the lifelines that permit nutrients, oxygen, and waste products to be exchanged with the blood vessels within the Haversian canal, Volkmann canal, and osteocytes. When a bone is loaded, the interstitial fluid within the lacuna and canaliculi is squeezed through a thin layer of non-mineralized matrix surrounding the cell bodies and cell processes toward the Haversian or Volkmann channels. This flow of fluid mobilizes the cell surface glycocalyx and initiates biochemical processes promoting osteogenesis [6].