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Adapting Injection Techniques to Different Regions
Published in Yates Yen-Yu Chao, Sebastian Cotofana, Anand V Chytra, Nicholas Moellhoff, Zeenit Sheikh, Adapting Dermal Fillers in Clinical Practice, 2022
Yates Yen-Yu Chao, Sebastian Cotofana, Nicholas Moellhoff
The medial and the lateral cheeks comprise the anatomic area lateral to the nose. It is majorly affected by age-related changes, as the underlying bone and the overlying soft tissues undergo substantial transformation during a lifetime. The underlying bone is affected by bone remodeling and recedes over time. Similarly, the height of the midface decreases over time, which causes the overlying soft tissues to descend. The descent in midfacial soft tissues mimics a loss of volume that is, however, only a partial cause of the age-affected midface. An inadequate strategy to restore a youthful face would be to volumize this region instead of lifting and repositioning the midfacial soft tissues. Relative volume changes with age and does not always proceed as reduction. More and younger patients ask for cheek enhancement because of suboptimal contours regardless of loss or even insufficiency. Filling with fillers where it looks deficient might not always be a success in patients with aging-related tissue descent. Anatomical knowledge gives us understanding of the reasons behind different morphological problems, not a map to fill something back in where the depression originates.
Pathogenesis: Molecular mechanisms of osteoporosis
Published in Peter V. Giannoudis, Thomas A. Einhorn, Surgical and Medical Treatment of Osteoporosis, 2020
Anastasia E. Markatseli, Theodora E. Markatseli, Alexandros A. Drosos
Unlike other resilient structures such as tendons, cartilage, and teeth, bone tissue, while it appears to be a “silent organ” that once ceases to grow, is actually a dynamic tissue that undergoes continuous remodeling in response to hormonal changes and mechanical stress. Bone remodeling occurs along with the development of the skeleton and is the main activity of bone tissue in adult life. Bone remodeling both plays a key role in the maintenance of the structure and the integrity of the skeleton and ensures maximum possible mechanical strength (23,24,38). It also regulates the levels of calcium concentration in serum (38).
Prostaglandins and the Mechanism of Bone Resorption
Published in Wilson Harvey, Alan Bennett, Prostaglandins in Bone Resorption, 2020
Osteocytic bone resorption is a controversial issue. There is little doubt that it does occur and that the surface of bone (Haversian Canals) lined with osteocytes is very much larger than the area covered by OCs. Limited resorption of perilacunar bone to a depth of approximately 1 μm has been observed,13 but Chambers2 stresses that resorption beyond the limit of perilacunar bone is always in conjunction with OC activity. The consensus is that a limited degree of osteocytic resorption is responsible for minute-to-minute changes in plasma calcium concentration, but that the majority of resorption in bone remodeling and local pathological bone destruction is performed by OCs with some debatable contribution from mononuclear phagocytes. There has been very little experimental work on the responses of osteocytes to PGs, largley because obtaining them in isolation poses methodological problems which are intractable at present. In calvaria exposed to PGE2 in culture, Schelling et al.6 found no evidence of osteocytic resorption in terms of increased metachromasia, lack of birefringence in the perilacunar matrix, or increase in lacunar size compared with control bones.
Irradiation affects the structural, cellular and molecular components of jawbones
Published in International Journal of Radiation Biology, 2022
Sridhar Reddy Padala, Bina Kashyap, Hannah Dekker, Jopi J. W. Mikkonen, Anni Palander, Nathalie Bravenboer, Arja M. Kullaa
Bone remodeling is a dynamic process; it occurs throughout the lifetime of an organism in a coordinated and tightly regulated manner in order to maintain a functional skeletal system. The bone remodeling process involves two opposing processes – bone resorption and bone formation (Mello et al. 2018) executed by three distinct cell types present in bone cells; osteoclasts, osteoblasts, and osteocytes. The physiological process of bone remodeling is based on the interactions not only between these cells but also multiple molecular agents including hormones, growth factors, and cytokines (Feng and McDonald 2011). Bone turnover is necessary to allow new bone to replace the existing bone, ensuring the adaptation of the newly formed bone to its microenvironment (Misch et al. 2001). Exposure to radiation causes a deterioration of the quantity and quality of bone by interfering with bone remodeling/turnover activity which ultimately impacts on the bone’s microstructure (Costa and Reagan 2019).
Efficacy and safety of sodium RISedronate for glucocorticoid-induced OsTeoporosis with rheumaTOid arthritis (RISOTTO study): A multicentre, double-blind, randomized, placebo-controlled trial
Published in Modern Rheumatology, 2021
Yuichiro Fujieda, Tetsuya Horita, Naoki Nishimoto, Kazuhide Tanimura, Yoshiharu Amasaki, Hideki Kasahara, Shin Furukawa, Tsuyoshi Takeda, Shinji Fukaya, Kazuo Matsui, Akito Tsutsumi, Akira Furusaki, Akira Sagawa, Kou Katayama, Kaoru Takeuchi, Kazuaki Katsumata, Takashi Kurita, Peter Shane, Masaru Kato, Kenji Oku, Shinsuke Yasuda, Masahiko Takahata, Norimasa Iwasaki, Tatsuya Atsumi
Management of osteoporosis complicated with RA is harder than other diseases, since RA itself affects bone metabolism. Bone remodeling is a process by which old bone is replaced by new bone, resulting in the renewal of the skeleton approximately every 10 years. The homeostasis of bone metabolism is orchestrated by osteoclasts and osteoblasts [20]. However, the maturation of osteoclasts in RA is enhanced by inflammatory cytokine in an osteoblast-independent manner [1]. The inflammation of the synovial tissues promotes osteoclastogensis that leads to both focal articular bone erosion at the site of pannus formation and systemic bone loss. Further, GC use for anti-inflammation has a devastating effect on bone in patients with especially active RA. GIO complicated with RA requires the most difficult management. The best management for GIO complicated with RA is keeping low disease activity of RA as well as maintaining high BMD.
Radiation alters osteoclastogenesis by regulating the cytoskeleton and lytic enzymes in RAW 264.7 cells and mouse bone marrow-derived macrophages
Published in International Journal of Radiation Biology, 2020
Ling Tong, Yuyang Wang, Jianping Wang, Feilong He, Jianglong Zhai, Jiangtao Bai, Guoying Zhu
The flexibility and strength of bone depend on the inorganic matrix, primarily composed of carbonated apatite, and organic matrix containing collagen type I and glycosaminoglycans (Segeletz and Hoflack 2016). To maintain skeletal microstructure, bone undergoes a continuous process termed bone remodeling that mainly depends on three types of bone tissue cells, namely bone-forming osteoblasts, bone-resorbing osteoclasts, and bone-supporter osteocytes (Teitelbaum 2007; Karsenty et al. 2009; Katsimbri 2017). Osteoblasts, exiting in the same bone environment with OC (osteoclast), not only provide a base of direct contact but also play a key role in producing extracellular proteins, especially RANKL and OPG, which exert biological effects through competitive binding to specific receptor RANK on OC precursor membrane, thus, to directly regulate osteoclast differentiation and bone resorption. Osteocytes, terminally differentiated osteoblasts, were revealed to support and serve as mechano-sensors of bone metabolism, and modulate osteoblasts and osteoclasts (Uda et al. 2017; He et al. 2019). The effects of the three aforementioned cell types are tightly coordinated in a spatiotemporal pattern to precisely control bone balance and to allow bone remodeling to be performed effectively throughout life (Sims and Martin 2014). Disruptions to the bone remodeling process may result in skeletal diseases such as osteoporosis or osteopetrosis.