Biochemistry of Exercise Training: Effects on Bone
Peter M. Tiidus, Rebecca E. K. MacPherson, Paul J. LeBlanc, Andrea R. Josse in The Routledge Handbook on Biochemistry of Exercise, 2020
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
Roy Palmer, Diana Wetherill in 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
Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss in Understanding Medical Terms, 2020
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.
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.
Clinical efficacy of the ‘sandwich technique’ in repairing cholesteatoma with labyrinthine fistula
Published in Acta Oto-Laryngologica, 2022
Huanhuan Sun, Taiqin Wang, Liangwen Shi, Suling Zhuang, Jianzhi Liu
Patients with labyrinthine fistulas theoretically showed the symptoms and signs of vestibular involvements, but many do not have vertigo. Preoperative vertigo accounted for 50% of patients in our study. Some scholars considered that symptoms only manifest when the cholesteatoma and endosteum are in contact after local bone resorption in the labyrinth [14]. Meanwhile, the cholesteatoma tissue blocks the conduction of barometric pressure change to the inner ear and impedes the stimulation of inflammation, resulting in the performance of vertigo may not be the same.
Finite element analysis of bone mechanical properties using MRI-derived bound and pore water concentration maps
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Thammathida Ketsiri, Sasidhar Uppuganti, Kevin D. Harkins, Daniel F. Gochberg, Jeffry S. Nyman, Mark D. Does
The contribution of pore water concentration to E and Y was low despite the range in Cpw being greater in the present set of cadaveric radii than in our previous study (Manhard et al. 2016). There are several possible explanations for this weak contribution of Cpw to the material properties of cortical bone. Firstly, our previous study in which both Cpw and Cbw significantly contributed to the prediction of bending strength of the radial diaphysis did not use FEA to account for role of bone structure in strength. By accounting for size and shape of each bone in the FE simulations, the importance of Cpw was perhaps diminished. Secondly, although cortical porosity is a known determinant of bone strength (Currey 1990; McCalden et al. 1993; Wachter et al. 2002), its negative correlation with yield stress has been shown to be rather weak (e.g. R2 = 0.22, p = 0.004) (Mirzaali et al. 2016). Lastly, higher pore water concentration (higher cortical porosity) does not necessarily translate to weaker bone if the Cpw is dictated by signal from the endosteum. Bone loss in the diaphysis of long bones occurs near the endosteum causing a ‘transition’ zone in which cortical bone appears to be trabecular bone (Zebaze et al. 2010). Loading cadaveric radii in four-point bending to failure and imaging the micro-structure of the diaphysis by high-resolution μCT, Bigelow et al. observed a stronger correlation between pores distributed away from the neutral axis and bending strength than between overall porosity and bending strength (Bigelow et al. 2019). Since the imaging resolution of this study is 1 mm, high Cpw values could also be influenced by bone marrow signal in the endosteum region, especially for bones with a thin cortical shell. The literature values of mean cortical thickness of radius bones (2.51 1995) and 5.75 2015) also shown that cortical thickness for some bone samples could be relatively close to the imaging resolution. This effect would be smaller in Cbw measurements since bone marrow signals are suppressed in the AIR pulse sequence.