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Biochemistry of Exercise Training: Effects on Bone
Published in Peter M. Tiidus, Rebecca E. K. MacPherson, Paul J. LeBlanc, Andrea R. Josse, The Routledge Handbook on Biochemistry of Exercise, 2020
Panagiota Klentrou, Rozalia Kouvelioti
Osteoclasts, the third major type of bone cells, derive from hemopoietic stem cells and are found in the endosteum. These cells are involved in bone resorption (breakdown of the bone extracellular matrix) by releasing lysosomal enzymes and acids and by doing so breaking down the protein and mineral components of the underlying bone matrix (136). Further, there are multiple functional interconnections of osteocytes, with each other as well as with osteoblasts and osteoclasts and vasculature, allowing the osteocyte network to respond to musculoskeletal-derived mechanical stimuli and thereby affecting bone metabolism (127). The interconnection between osteocytes and bloodstream also allows the exposure of osteocytes to systemic messages from distant tissues. These messages are manifested by extracellular levels of minerals (e.g., inorganic phosphate) and endocrine hormones, mainly oestrogen, parathyroid hormone, and 1,25(OH)2D3 (127).
Orthopaedics
Published in Roy Palmer, Diana Wetherill, Medicine for Lawyers, 2020
Figure 13.1 shows the various parts of the bone, which may need further description. A long bone, such as the tibia (shin bone) or humerus (the upper arm bone), or short long bones, such as the metacarpals (the bones you see on the back of the hand) and metatarsals (in the feet) are divided up into several parts for descriptive purposes. At either end is an epiphysis. The periosteum is an outer membrane of bone-forming tissue and this assists with growth during the growing period and is also responsible for laying down bone during fracture healing throughout the patient’s life. Endosteum is a similar lining of tissue within the bone between the compact (or hard) outer bone and the spongy bone of the medullary cavity (the marrow of the bone). Where a bone takes part in a joint it is covered by what is known as articular cartilage. A bone derives its nutrition from the nutrient arteries that reach it either by perforating the hard outer bone (the cortex) or by way of the joint capsules, which are connected to the bone near the edges of the joint.
The Musculoskeletal System and Its Disorders
Published in Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss, Understanding Medical Terms, 2020
Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss
The inner cavity of the bone is referred to as the medullary cavity or marrow cavity because it contains the bone marrow (medulla osseum). The cavity is lined by connective tissue called the endosteum (endo-=inner; osteum or osteo- = bone). The outer sheath of tissue surrounding the bone is known as the pertosteusa, which covers all of the bone except the articular end, the part forming a joint with another bone. Bone tissues are traversed by a system of canals through which blood vessels, lymph vessels, and nerves enter the bone via the periosteum.
Prediction of cortical bone mineral apposition rate in response to loading using an adaptive neuro-fuzzy inference system
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Rakesh Kumar, Vimal Kumar Pathak
Present study establishes a robust relationship between the loading parameters and mineral apposition rate. The correlation observed at the endosteal surface was much stronger than the periosteal surface when compared. The outcomes of the study recommend that the ANFIS model's prediction accuracy is very remarkable as compared to other ANN modals present in the literature. Testing and checking of the present ANFIS model also show a substantial improvement over the other model in estimating the values of the bone structure parameters i.e. MAR as a function of loading parameters. Additionally, influence of individual input parameter also helped in understanding the influence on mineral apposition rate. The findings of the present paper are an important step towards understanding how mechanical loading and their parameters influence bone modelling and remodelling rate.
Cold stress modulates redox signalling in murine fresh bone marrow cells and promotes osteoclast transformation
Published in Archives of Physiology and Biochemistry, 2020
Siddhartha Singh, Ajeya Nandi, Oly Banerjee, Ankita Bhattacharjee, Shilpi Kumari Prasad, Bithin Kumar Maji, Adipa Saha, Sandip Mukherjee
Previously it has been reported that stronger cold stress at 4 °C affects and damages bone architecture (Tazawa et al.2004). In accordance with this, the histopathological analysis in the present set up revealed that varying intensities of cold stress induces the formation of various osteoporotic cavities and an inclination in the number of erosion cavities in the femur of mice exposed to 15 °C and 8 °C cold stress. Furthermore, numerous osteoclastic cells were observed in the femur of the mice exposed to stronger cold stress i.e. 4 °C. This result was in compliance with that of Khattab et al. (2013), who reported that femur bones in ovarectomised rats showed resorption cavities, changes in femur bone architecture and presence of osteoclastic cells which lead to the initiation of osteoporosis. Studies also reported that in ovarectemized rat, there was a decrease in cortical bone thickness and the endosteal surface was irregularly eroded, which lead to the destruction of bone architecture and induction of osteoporosis (Weber et al.2004, Park et al. 2008). In the present study, stronger cold stress i.e. 8 °C and 4 °C caused a significant decrease in the maximum bone diameter, cortical distance and lacunar area in the femur of mice. Based on the results of the histometric analysis, we can speculate that cold stress might have modulated osteoclastic activity thus leading to osteoclastogenesis.
Lower initial electrode impedances in minimally invasive cochlear implantation
Published in Acta Oto-Laryngologica, 2019
Xiao Liu, Lulu Xie, Yunxiu Wang, Beibei Yang
In 1993, Lenhardt [5] described the ‘soft surgery’ technique and the concept of atraumatic insertion for cochlear implantation for the first time. The principles of this technique include drilling a minimal cochleostomy, maintaining the integrity of the cochlear endosteum while drilling, avoiding suction of the perilymph, preventing the blood or bone dust from entering the scala tympani, and sealing the cochleostomy hole immediately after the cochlear endosteum is incised and an electrode array is inserted. However, when drilling the cochleostomy in the area anterior-inferior to the round window, creating bone dust, tearing the endosteum, and acoustic trauma are still unavoidable. Moreover, there is a potential risk that an electrode array is placed outside the scala tympani and into the scala vestibule [6,7]. In contrast, grinding the bone is much less when using the round window approach. In addition, it is much easier to keep the round window membrane intact than maintaining the endosteum of the cochlear duct undamaged before the insertion of the electrode arrays. A minimal incision in the round window membrane followed by the electrode insertion may completely avoid the perilymph loss. With the advances of the surgical techniques for opening the facial recess, together with new types of fine and soft electrode arrays being manufactured, the round window approach is considered to be a minimally invasive technology.