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Comparative Anatomy, Physiology, and Biochemistry of Mammalian Skin
Published in David W. Hobson, Dermal and Ocular Toxicology, 2020
It has been postulated that the hollow tubular structure of the microfibrils is similar to the microfibrils of elastic tissue. Therefore, they could be an extension of the elastic tissue system. It was also thought that they were related to the oxytalan fibers.192 Bundles of these tubular microfibrils have been related to the epidermaldermal junction and are further identified as oxytalan fibers.193
Photodamaged and aged skin
Published in Giuseppe Micali, Francesco Lacarrubba, Dermatoscopy in Clinical Practice, 2018
Anne-Sophie Brillouet, Michael D. Southall
Dermal photoaging is manifested primarily as the loss and disorganization of collagen fibrils including loss of fibrillar collagens (I and III in the dermis, and VII anchoring fibrils at the dermo-epidermal junction [DEJ])4–6 and the accumulation of abundant abnormal amorphous elastin fibers containing material, namely elastosis, at the junction of papillary and reticular dermis.7 Sun-exposure-increased elastin fibers are abnormally located in the areas previously held by collagen.8 The oxytalan fibers at the DEJ are markedly reduced, and discrete microfibrillar bundles are rarely observed in photoaged skin.9 The loss of elastic fiber integrity leads to a progressive reduction of skin elasticity and manifests as skin wrinkles. Photoaged skin has reduced levels of hyaluronic acid and elevated levels of chondroitin sulphate proteoglycans.10 The decreased hyaluronic acid content in the dermis during photoaging and the subsequent reduced water binding capacity skin can also contribute to skin wrinkling and altered elasticity. While the biology of photoaging in the epidermis and dermis has been well documented, few studies have examined the changes in skin glyphics during the aging process.
The Pineal Gland
Published in Nate F. Cardarelli, The Thymus in Health and Senescence, 2019
Neurotransmitter and hormone types found in the pineal are also present in the retina. Arginine vasopressin (AVP), oxytocin (OT), and neurophysin, the carrier for AVP and OT, have been found in both the pineal and retina of man, rats, and bovines.225 AVP is probably not synthesized in the retina but enters from the pineal during the dark period. Retinal concentrations of all three vary with light intensity. In a recent review paper discussing the parallels between the pineal and the retina, retina-pineal connections are discussed, as is the similarity of neurotransmitters and hormones produced in the eye and pineal.226 Opsin and taurine, for instance, are present in pinealocytes and the retina. Both the eye and the pineal synthesize melatonin, no other source of production being known. Oxytalan fibers are found in the rat pineal, dermis, and comea.61 Pineal content increases gradually with age. The pineal organ of the lamprey eel contains a substance similar to, or identical with, the photopigment rhodopsin.227 S-antigen is found in both the pineal and the eye. In neonatal rats, immunoreactivity with the monoclonal antibody is first noted at 3 d of age.228 Although the nature of the S-antigen is unknown, it may be rhodopsin kinase I, the enzyme that down-regulates photolyzed rhodopsin.229 S-antigen is found in the pineal and retinas of rats, hedgehogs, gerbils, and cats—evenly distributed in the respective cells. Van Veen et al. find that the immune reaction implies the presence of S-antigen in planaria and starfish ocelli, and in the eyes of scallops, crayfish, lamprey eel, salmon, quail, frog, turtle, and hamster.230t was also evident in the pineals of all vertebrates studied, although weakly so in the one turtle species examined. Menaker provides compelling evidence that the retina and pineal gland, at least of birds and some lizards, fulfill similar endocrine roles.231
Osteocalcin, Azan and Toluidine blue staining in fibrous dysplasia and ossifying fibroma of the jaws
Published in Alexandria Journal of Medicine, 2018
Samuel Ebele Udeabor, Akinyele Olumuyiwa Adisa, Anna Orlowska, Poju Chia, Robert A. Sader, Shahram Ghanaati
Oxytalan fibres (so called because they are resistant to acid hydrolysis), have been reportedly seen in FOLs and they were found more in OF than FD.12 In our study, Toluidine blue, which is acidophilic, was found to strongly stain 42.3% of OF and 14.2% of FD, this difference was statistically significant. Thus, we suggest that strong Toluidine blue staining of the fibrous connective tissue stroma of FOLs may most likely indicate an OF. A study by Gulati et al.,10 using both trichrome and modified Halmi staining in FOLs, showed more oxytalan fibres in OF by the strong purple coloration observed compared to FD cases. They also suggested that the use of such histomorphometric tests might be a solution to the misdiagnosis of these two FOLs, as well as a pointer to their origin. From our study and that by Gulati et al.,10 we advise that in facilities where genetic analysis or immunohistochemical processing may be challenging, a minimum of metachromatic or trichrome staining as suggested above may be useful to help resolve diagnosis of OF and FD.
Geroderma osteodysplasticum: Histological features and the role of panel-based exome sequencing in diagnosis
Published in Ultrastructural Pathology, 2018
Rosalyn Jewell, Paul Brewer, Sophie Stenton, Ian R Berry, Sue Chatfield, James A Fernandes, Cesar Peres, Bart E Wagner, Christopher Bennett
Similarly, there is significant overlap between the histological features of GO, cutis laxa syndromes, and WSS. As mentioned previously, it was thought that WSS and GO were part of the same spectrum of disease.18 Indeed, it has been noted that in WSS there is a reduction in oxytalan fibers within the papillary dermis, thickened fibers within the mid-dermis, and a paucity of elastic fibers in the reticular dermis. Aggregates of fragmented elastic fibers are also described within the deep dermis, which is not dissimilar from some cases of GO.11,19,20