Skeletal System
David Sturgeon in Introduction to Anatomy and Physiology for Healthcare Students, 2018
There are three different types of cartilage: hyaline, elastic and fibrocartilage. The term hyaline is derived from the Greek for ‘glass-like’ and describes its translucent blue-white appearance. It is the most abundant cartilage in the body and is found in a wide variety of locations. It protects the epiphyses at moveable joints (articular cartilage), it connects the ribs to the sternum (costal cartilage), it supports the end of the nose (nasal cartilage) and is present in the larynx and trachea (respiratory cartilage). Elastic cartilage is similar to hyaline cartilage but it has a larger number of elastin fibres which provide its yellowish appearance and greater flexibility. Elastic cartilage helps to define and maintain the shape of an area where it is located and provides support for surrounding tissue. For example, it is found in the outer ear (auricle), the auditory (Eustachian) tubes at the back of the nose, and the epiglottis of the voice box (larynx). However, it is possible to transplant cartilage from one area to another and costal cartilage from the ribcage can be used to reconstruct the ear (elastic cartilage).
Cartilage Collagens
Marcel E. Nimni in Collagen, 1988
Hyaline cartilage is the most common and well-characterized type of cartilage which covers the articular surface of bones and supports tracheal tubes, larynx, and ventral ends of ribs. It also provides the embryos with temporary skeletons which are eventually resorbed and replaced by bone. Hyaline cartilage is, as the name implies, semitransparent glassy tissue with an opalescent bluish-white tint. Microscopically, the intercellular substance appears homogenous and structureless, because the collagen fibers are relatively small in size and thickness and are masked by amorphous ground substance in which they are embedded (Figure 1). When typical hyaline cartilage is observed under an electron microscope, collagen appears as a branching meshwork of fine fibrils (diameter 10 to 20 nm) which is lacking in characteristic cross-striation pattern.11 Adult articular cartilage, however, often contains larger fibrils (diameter 30 to 200 nm) with cross striation of 64-nm periodicity.12 Apart from the morphological heterogeneity, the great majority of these fibers is derived from type II collagen molecules which consist of three identical α1(II) chains.13,6
Hyaline Bodies in the Walls of Odontogenic Cysts
Roger M. Browne in Investigative Pathology of the Odontogenic Cysts, 2019
Hyaline bodies are morphologic curiosities that have been described in various unrelated conditions and whose presence occasionally contribes to a diagnosis. The finding of extracellular hyaline bodies within the epithelial linings and connective tissue walls of odontogenic cysts, although of no diagnostic value, has stimulated a variety of studies to determine their origin, structure and possible role in pathogenesis. Those found within lining epithelium have generated most interest as they are not readily associated with other local lesions and appear to be specific to odontogenic cysts. By contrast, those within the connective tissue capsule are associated with local inflammatory changes of the ‘foreign body’ type and are known to occur at other sites both within the oral cavity and elsewhere in the body.
The diagnostic methods in the COVID-19 pandemic, today and in the future
Published in Expert Review of Molecular Diagnostics, 2020
So Yat Wu, Hoi Shan Yau, Man Yee Yu, Hin Fung Tsang, Lawrence Wing Chi Chan, William Chi Shing Cho, Allen Chi Shing Yu, Aldrin Kay Yuen Yim, Marco J W Li, Yin Kwan Evelyn Wong, Xiao Meng Pei, Sze Chuen Cesar Wong
The macroscopic features of COVID-19 included pleurisy, pericarditis, lung consolidation, and pulmonary edema. Lung weight may be increased above normal. Microscopic histological examination of the lungs of patients died from COVID-19 showed signs compatible with acute respiratory distress syndrome (ARDS). For example, the presence of bilateral acute changes with diffuse alveolar damage (DAD) with vascular congestion, intra-alveolar edema, hemorrhage, proteinaceous exudate, macrophages, evidence of epithelial infection with cytopathic effects of pneumocytes such as denudation and active hyperplasia of pneumocytes; multinucleated giant cells formation and patchy lymphocytic inflammatory cellular infiltration (consisting of mainly CD-4 positive lymphocytes, eosinophils, and neutrophils). However, hyaline membrane formation may not be seen. Microvascular fibrinoid change with hyaline thrombi and edema and extensive intra-alveolar fibrinous aggregates with acute fibrinous and organizing pneumonia (AFOP) pattern were also noted. Fibrotic changes include organizing pneumonia with progression to fibrosis, intra-alveolar fibroelastosis, and fibrotic nonspecific interstitial pneumonia (F-NSIP) [55,56].
Intrapericardial pneumonectomy for unicentric hilar castleman disease
Published in Acta Chirurgica Belgica, 2021
Murat Kara, Berker Ozkan, Melike Ulker, Deniz Tugcu, Gulcin Yegen
Castleman disease is a rare benign lymphoproliferative disorder of the lymph nodes with an unknown etiology. It was first reported by Castleman and Towne from Massachusetts General Hospital in 1954 [1]. The primary pathology is angiofollicular lymph node hyperplasia. Histologically, it has three forms as hyaline vascular, plasma cell and mixed types. Clinically, it presents with either unicentric or multicentric disease. Unicentric Castleman Disease is usually of the hyaline vascular type, whereas multicentric disease is usually the plasma cell or mixed type. The unicentric form is often a localized solitary tumor, whereas the multicentric form is characterized by generalized lymphadenopathy and systemic symptoms. The unicentric form is mostly located at the mediastinum and abdomen; however, intrapulmonary localization with parenchymal involvement is extremely rare. Preoperative diagnosis is often a challenge before the histologic examination of the lymph nodes, and no specific radiologic diagnostic criteria exist for Castleman disease. Thus, surgical resection becomes the diagnosis and treatment of choice with favorable results for the unicentric form of Castleman disease with intrapulmonary involvement [2].
Sustained Remission with Tocilizumab in Refractory Relapsing Polychondritis with Ocular Involvement: A Case Series
Published in Ocular Immunology and Inflammation, 2021
Rebecca Farhat, Gaël Clavel, Delphine Villeneuve, Youssef Abdelmassih, Marwan Sahyoun, Eric Gabison, Thomas Sené, Isabelle Cochereau, Cherif Titah
Relapsing polychondritis (RP) is a rare autoimmune disorder characterized by recurrent, widespread, and potentially destructive inflammation of the cartilaginous tissue.1 Its incidence is estimated to be around 3.5/1,000,000/year. All types of cartilage may be involved: the elastic cartilage of the nose and ear, the hyaline cartilage of tracheobronchial tree, and proteoglycan-rich structure like the eye are some examples. The diagnosis is mainly based on clinical criteria, McAdam’s criteria. It includes six clinical features: auricular chondritis, non-erosive, seronegative inflammatory polyarthritis, nasal chondritis, ocular inflammation, respiratory tract chondritis, and cochlear and/or vestibular dysfunction. To confirm RP diagnosis, one must have any of the following one McAdam’s criterion plus histopathological confirmation or two McAdam criteria and positive response to corticosteroids or dapsone or at least three McAdam’s criteria.1,2 Ocular involvement is frequent and found in up to 51% of cases with episcleritis and scleritis being the most common.3,4 RP is usually treated with steroids and conventional immunosuppressant, or antitumor necrosis factor-alpha (TNF-alpha) agents.5 However, it is not clear what should be the next therapeutic option in refractory cases.
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