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Dermoepidermal junction
Published in Lionel Fry, Atlas of Bullous Diseases, 2020
Since the antigens are components of the basement membrane region, it is important to know its structure. On electron microscopy the basement membrane, which separates the epidermis and dermis, is composed of an upper translucent area, the lamina lucida, and an electron-dense region, the lamina densa (Figure 4.1). The basal layer of ker-atinocytes is attached to the basement membrane by electron-dense structures termed hemidesmosomes. The structures have an intracellular and an extracellular component. The latter consists of anchoring filaments which traverse the lamina lucida and end in the lamina densa, whose constituents include laminin 5 and type IV collagen. Below the lamina densa are anchoring fibrils composed of type VII collagen which anchor the lamina densa to the dermis.
Pregnancy-Related Protein Concentrations and Hormone Levels in Trophoblastic Diseases
Published in Gábor N. Than, Hans Bohn, Dénes G. Szabó, Advances in Pregnancy-Related Protein Research, 2020
Fay et al.60 discovered two more antigens of fetal origin like AFP; both FA-1 and FA-2 appear in significant quantity in amniotic fluid samples and fetal serum from the second or third trimester. Neither is identifiable from maternal serum, decidua, or fetal membranes. Third-trimester trophoblastic cells contain FA-1, but not FA-2.61 The latter was found to be present in the lamina densa/sublamina densa region of the basement membrane zone in adult as well as in fetal skin.62 Similar to AFP, FA-2 is unlikely to be of significance in trophoblastic diseases, and researchers have published no findings with respect to FA-1 in this regard.
The Structure of Odontogenic Cysts
Published in Roger M. Browne, Investigative Pathology of the Odontogenic Cysts, 2019
Ultrastructurally, the epithelial cells demonstrate the same basic organelles as in oral mucosal epithelium, but they lack the orderly progression of changes of the mucosa, as the cells migrate from the basal to the surface layers.67,68 Large numbers of organelles are still present in the surface cells, although histochemical studies indicate a reduction in oxidative enzyme activity towards the epithelial surface.25 Acid phosphatase activity remains largely membrane-bound in the surface layers.24 This relative lack of cellular differentiation is accompanied by a relative lack of blood group reactivity in the cell membranes.28,29,64 Prominent desmosomes are present, although there are wide intercellular spaces, particularly in the presence of inflammation.19 Scanning electron microscopy of the luminal surface of the epithelium reveals channels between the cells, some of which contain polymorphonuclear leukocytes.69,70 The basement membrane has a lamina lucida and lamina densa supported by anchoring fibrils and microfilaments.19
Spatial composition and turnover of the main molecules in the adult glomerular basement membrane
Published in Tissue Barriers, 2023
David W. Smith, Azin Azadi, Chang-Joon Lee, Bruce S. Gardiner
The fiber network across the GBM appears to be non-uniformly distributed, as can be identified by transmission electron microscopy (TEM) (for example, Figure 2 in [25] or Figure 8a in [26]). Traversing the GBM from the endothelial side to the epithelial side, three distinct regions are usually identified: (i) the lamina rara interna (LRI), (ii) the lamina densa (LD), and (iii) the lamina rara externa (LRE).25 Note that there are several naming conventions for basement membrane that have arisen. We intend to use LRI, LD, and LRE here when referring to the GBM, as this provides a convenient reference to locations within the GBM. Further, lamina densa is sometimes used synonymously with basement membrane (e.g. Mouse Genome Informatics, Gene Ontology Browser27) or a name given based on optical appearance, rather than location.
Amelioration of renal cortex histological alterations by aqueous garlic extract in gentamicin induced renal toxicity in albino rats: a histological and immunohistochemical study
Published in Alexandria Journal of Medicine, 2021
Hala ZE Mohamed, Merry BK Shenouda
Examination of the ultrastructure of the glomerulus in the control group showed the presence of glomerular capillary loops lined by fenestrated endothelium. They are surrounded by podocytes which had irregular nuclei. Primary and secondary processes could be observed extend from the cell body of podocytes. The secondary processes appeared in contact with the outer surface of the glomerular basement membrane. The glomerular basement membrane appeared with regular thickness and consisted of central electron-dense lamina densa and on both sides of which electron lucent lamina rara. Mesangial cells surrounded by mesangial matrix were noticed (Figure 6(A)). Examination of the cells of the proximal convoluted tubules showed the presence of rounded euchromatic nucleus with prominent nucleolus. The cells showed basal infoldings of the cytoplasm with numerous mitochondria appeared longitudinally arranged. Microvilli could be clearly observed on the luminal surface of the cells of the proximal convoluted tubule (Figure 7(A)). The cell of the distal convoluted tubules showed the presence of euchromatic rounded central nucleus, many mitochondria and few apical blunt microvilli (Figure 8(A)).
Structural, ultrastructural, and morphometric study of the zebrafish ocular surface: a model for human corneal diseases?
Published in Current Eye Research, 2018
Domenico Puzzolo, Antonina Pisani, Consuelo Malta, Giuseppe Santoro, Alessandro Meduri, Francesco Abbate, Giuseppe Montalbano, Edward Wylegala, Rosa Alba Rana, Fabio Bucchieri, Antonio Ieni, Pasquale Aragona, Antonio Micali
The epithelium was formed by two layers each of basal and intermediate cells and by a single layer of superficial cells (Figure 2B). Superficial cells showed polygonal shape, irregular size, and many apical microridges, which formed intricate patterns on the cellular surface (Figure 2C). Basal cells showed elliptical nucleus with well evident nucleolus, many organelles, and a peripheral ring of intermediate filaments (Figure 2D). At higher magnification (Figure 2E), many De could be demonstrated between basal cells. The inferior pole of basal cells showed two differently oriented layers of intermediate filaments and many Hd (Figure 2F). The cellular membrane had an irregular course; the basement membrane was formed by lamina lucida and lamina densa. No Bowman’s layer was present (Figure 2G).