Structure of Initial and Collecting Lymphatic Vessels
Waldemar L. Olszewski in Lymph Stasis: Pathophysiology, Diagnosis and Treatment, 2019
SEM has enhanced our conception also with respect to the histological differentiation of the outer vascular wall area of small lymphatics and its structural relation to the surrounding tissue. In SEM micrographs the outer endothelial surface is found to be covered by a dense layer of fine reticular fibers arranged in a criss cross pattern. Most fibers are arranged in a circular orientation (see Figure 12 b). This layer is part of a basement membrane whose ground substance is very sparsely developed. TEM reveals that the basement membrane represents a layer consisting of essentially two parts: (1) a thin basal lamina (300 to 700 Å) rich in mucopolysaccharides and proteins and containing a fine filamentous material and (2) a network of reticular fibrils blending with elastic and collagenous fibrils of the adjacent tissue.75 With the aid of the SEM mainly the second component of the basement membrane can be visualized in initial lymphatics. A well-defined basal lamina should first occur after TEM findings58 around larger lymphatics which are already furnished with smooth muscle cells. In fixed tissue preparations the layer of reticular fibers cannot be removed from the lymphatic endothelium due to their firm adhesion to these cells. Single fibers and fiber strands extend from the reticular fiber system toward the tissue; in this manner the system is joined to the collagenous fibers of the connective tissue (see Figure 12 a).
Actions of Dopamine on the Skin and the Skeleton
Nira Ben-Jonathan in Dopamine, 2020
Structures within the dermis include Excretory and secretory glands (sebaceous, eccrine, and apocrine). Sebaceous glands secrete triglyceride and cholesterol-rich sebum that lubricate the skin and keep it supple and waterproof. They are often associated with hair shafts.Hair follicles and nails. The hair follicle provides a protective niche to several stem cell populations in the skin, including keratinocyte stem cells, melanocyte stem cells, a population of epidermal neural crest stem cells, and the dermal stem cell compartment, the dermal papilla. These stem cells are most active during wound healing.Sensory nerve receptors of Merkel and Meissner’s corpuscles (touch receptors), Pacinian corpuscles (pressure receptors), and Ruffini corpuscles (mechanoreceptors). Fingerlike projections within the papillary region of the dermis extend toward the epidermis. The thick reticular region has collagenous, elastic, and reticular fibers.
Skin
Pritam S. Sahota, James A. Popp, Jerry F. Hardisty, Chirukandath Gopinath, Page R. Bouchard in Toxicologic Pathology, 2018
Lesions in the dermis may also affect the reticular fibers and ECM. Dense packing and homogenization of collagen bundles, with concomitant loss of elastic fibers, are key features of scleroderma. Subcutaneous administration of porcine growth hormone to beagle dogs caused a dose-related increased thickness of dermal collagen manifested as large skin folds on the forehead and face and was considered a pharmacologic effect (Prahalada et al. 1998). Solar elastosis is the result of sun damage to skin (Knowles and Hargis 1986) or may be induced in rats by chronic exposure to UV irradiation (Nakamura and Johnson 1968; Berger et al. 1980; Fisher et al. 2002; Tsukahara et al. 2012). It is characterized by aggregates of thick, basophilic elastic fibers in the superficial dermis. Elastosis may also be chemically induced by penicillamine characterized by increased amounts of soluble collagen, alterations of elastic fibers, and protrusions that establish themselves perpendicular to the long axis of elastic fibers (Smith 1994). Amyloid deposits, characterized by pale eosinophilic material that has apple-green dichroism when stained with Congo red and viewed under polarizing light, may be found anywhere in the dermis and are often associated with systemic amyloidosis (Faccini et al. 1990).
A comparative study of different amniotic membrane orientations during extraocular muscle surgery in rabbits
Published in Current Eye Research, 2018
Rehab Rashad Kassem, Randa Mohamed Abdel-Moneim El-Mofty, Mustafa Mahmoud Khodeir, Wael Mostafa Hamza
The amniotic membrane (AM) is the inner layer of the fetal membranes. It is 0.02–0.05 mm thick and consists of three different layers: the epithelium, basement membrane and stroma. The epithelium is a monolayer of metabolically active cuboidal cells with microvilli present on its apical surface. The epithelium rests upon a thick basement membrane composed of reticular fibers and is made up of type IV, V and VII collagen in addition to fibronectin and laminin. The stroma is avascular and is further divided into three contiguous but distinct layers: the inner compact layer (which is in contact with the basement membrane and contributes to the tensile strength of the AM), middle fibroblast layer (which is thick and made up of a loose fibroblast network) and the outermost spongy layer. The AM is immunologically inert. Following transplantation, it acts as a biological barrier between potentially adhesive surfaces, and its stromal matrix reduces inflammation, neovascularization and scarring.2–5
Effect of iron chelation therapy on EPO-STAT5 signalling pathway and EPO resistance in iron-overloaded low-risk myelodysplastic syndrome patients
Published in Hematology, 2020
A total of 61 MDS patients in our Hospital between January 2013 and May 2019 were included into this study. The patients with uraemia, hyperparathyroidism, chronic blood loss, aluminium poisoning, haemolysis, vitamin deficiency and EPO antibody-mediated pure red aplastic and those who use ACEI/ARB drugs were excluded from this study. Thirty-two patients were male and 29 patients were female, and the median age of these patients was 54 years (range: 28–81 years). The diagnostic criteria was in reference with the related literature [15], and typing was in accordance with the 2008 WHO classification standards [16]: three case was refractory cytopenia with single dysplasia (RCUD), 10 cases were refractory anaemia with ringed sideroblasts (RARS), one case was 5q− syndrome and 47 cases were refractory cytopenia with multi-lineage abnormal (RCMD). The MDS Revised International Prognostic Scoring System (IPSS-R) is used for low-risk or extremely low-risk groups. TP53, JAK2 and SF3B1 gene mutation were detected. Bone marrow biopsy and plastic embedded sections were stained with Gomori's method, and density of reticular fiber was analyzed semi quantitatively. ++~+++ defined as myelofibrosis. The patients’ characteristics were presented in Table 1.
Attenuation of streptozotocin induced high fat diet exacerbated dyslipidemia mediated hepatic and aortic injuries in male pigs by camel milk
Published in Egyptian Journal of Basic and Applied Sciences, 2023
Hadiza Bello Rilwan, Sunday Samuel Adebisi, James Abrak Timbuak, Sunday Blessing Oladele, Aliyu Muhammad, Wusa Makena, Adamu Abubakar Sadeeq
The process of silver impregnation displays reticular fibers. The reticular fibers are clearly defined strands in a normal liver, but they reveal a discontinuous pattern in a necrotic and cirrhotic liver. The tissues were oxidized for 3 minutes in potassium permanganate, rinsed in distilled water, and then de-colored for 2 minutes in 2% oxalic acid. After washing and sensitizing the tissues with 4% iron alum for 10 minutes, they were rinsed with distilled water and impregnated with an ammoniacal silver solution for 11 seconds. The tissues were then rinsed in distilled water, fixed with 2% aqueous sodium thiosulfate (hypo) for 2 minutes, washed in distilled water, and counterstained with neutral red for 2 minutes. The tissue was then dehydrated, cleared, and mounted [30].
Related Knowledge Centers
- Basement Membrane
- Collagen
- Reticular Cell
- Lymphatic System
- Bone Marrow
- Connective Tissue
- Liver
- Carbohydrate
- Collagen, Type Iii, Alpha 1
- Silver Staining