Search results
Results from the WOW.Com Content Network
An osteoclast is a large multinucleated cell and human osteoclasts on bone typically have four nuclei [5] and are 150–200 μm in diameter. When osteoclast-inducing cytokines are used to convert macrophages to osteoclasts, very large cells that may reach 100 μm in diameter occur. These may have dozens of nuclei, and typically express major ...
When the gap between the bone ends is less than 0.01 mm, and interfragmentary strain is less than 2%, contact healing can occur. In this case, cutting cones, which consists of osteoclasts, form across the fracture lines, generating cavities at a rate of 50–100 μm/day.
The osteoclast then induces an infolding of its cell membrane and secretes collagenase and other enzymes important in the resorption process. High levels of calcium , magnesium , phosphate and products of collagen will be released into the extracellular fluid as the osteoclasts tunnel into the mineralized bone.
Bone tissue is removed by osteoclasts, and then new bone tissue is formed by osteoblasts. Both processes utilize cytokine (TGF-β, IGF) signalling.In osteology, bone remodeling or bone metabolism is a lifelong process where mature bone tissue is removed from the skeleton (a process called bone resorption) and new bone tissue is formed (a process called ossification or new bone formation).
The CTX test measures for the presence and concentration of a crosslink peptide sequence of type I collagen, found, among other tissues, in bone. This specific peptide sequence relates to bone turnover because it is the portion that is cleaved by osteoclasts during bone resorption, and its serum levels are therefore proportional to osteoclastic ...
Bisphosphonate molecules then attach to and enter osteoclasts where they disrupt intracellular enzymatic functions needed for bone resorption. [38] There are two classes of bisphosphonate compounds: non-nitrogenous (no nitrogen in R 2) and nitrogenous (R 2 contains nitrogen). The two types of bisphosphonates work differently in inhibiting ...
The inhibition of osteoclast differentiation and function, precipitated by drug therapy, leads to decreased bone resorption and remodelling. [31] [39] Evidence also suggests bisphosphonates induce apoptosis of osteoclasts. [40] Another suggested factor is inhibition of angiogenesis due to bisphosphonates; this effect remains uncertain.
Initially, there is a marked increase in the rate of bone resorption in localized areas, caused by large and numerous osteoclasts. Radiographs at this phase show lucency in the affected bone. These localized areas of pathological destruction of bone tissue (osteolysis) are seen radiologically as an advancing lytic wedge in long bones or the skull.