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Ground Substance (ground + substance)
Selected AbstractsImmunocytochemical characterization of ectopic enamel deposits and cementicles in human teethEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 1 2003Dieter D. Bosshardt Despite the relative frequency and clinical relevance of radicular enamel deposits and cementicles, their etiology and nature are unknown. The purpose of the present study was therefore to evaluate the presence and distribution of mineralization-associated non-collagenous matrix proteins (NCPs) in various types of root-associated ectopic mineralizations. Human teeth were processed for embedding in epoxy or acrylic resins. Tissue sections were incubated with antibodies to amelogenins (AMEL), bone sialoprotein (BSP), and osteopontin (OPN). Radicular enamel deposits contained residual organic matrix that labeled for AMEL. In contrast, BSP and OPN were not detected in the residual enamel matrix, they were found in the cementum deposited on its surface as well as in collagen-free cementicle-like structures in the adjacent periodontal ligament. True cementicles consisted of a collagenous matrix intermixed with a non-collagenous ground substance. Labeling for BSP and OPN was mainly associated with the interfibrillar ground substance. No immunoreactivity for AMEL was detected in cementicles. These data indicate that ectopic enamel deposits on the root retain a high amount of AMEL, whereas cementicles contain BSP and OPN, two NCPs typically found in bone and cementum. These NCPs may, like in their normal tissue counterparts, play a role in the mineralization process. [source] The extracellular matrix can regulate vascular cell migration, proliferation, and survival: relationships to vascular diseaseINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 3 2000Elaine W. Raines The extra cellular matrix (ECM) of the normal artery wall is a collection of fibrous proteins and associated glycoproteins embedded in a hydrated ground substance of glycosaminoglycans and proteoglycans. These distinct molecules are organized into a highly ordered network that are closely associated with the vascular cells that produce them. In addition to providing the architectural framework for the artery wall that imparts mechanical support and viscoelasticity, the ECM can regulate the behaviour of vascular cells, including their ability to migrate, proliferate and survive injury. The composition of the ECM is different within intimal lesions of atherosclerosis, which are composed of monocytes and lymphocytes from the circulation and smooth muscle cells (SMC) that migrate from the media to the intima ( Ross 1993, 1999), and these differences may contribute to the altered phenotype of vascular cells within lesions. This review will briefly outline the ECM changes observed in atherosclerosis and restenosis and the potential relationship of these changes to altered vascular cell functions. [source] Comparative Histology and Vibration of the Vocal Folds: Implications for Experimental Studies in Microlaryngeal Surgery ,THE LARYNGOSCOPE, Issue 5 2000C. Gaelyn Garrett MD Abstract Objectives/Hypothesis To determine the most suitable animal model for experimental studies on vocal fold surgery and function by a histological comparison of the microflap surgical plane and laryngeal videostroboscopy (LVS) in different species of animals. A second goal was to determine how the layered vocal fold structure in humans and three different animal species affects surgical dissection within the lamina propria. Study Design Prospective laboratory. Methods Three larynges each from dogs, monkeys, and pigs were compared with three ex vivo human larynges. Microflap surgery was performed on one vocal fold from each larynx. Both the operated and nonoperated vocal folds were examined histologically using stains specific for elastin, mature collagen, and ground substance. Based on the histological results, LVS was performed on two dogs and two pigs after first performing a tracheotomy for ventilation and airflow through the glottis. Arytenoid adduction sutures were placed to facilitate vocal fold adduction. Results The distributions of the collagen and elastin fibers were found to differ among the species with concentrations varying within species. Unlike the human vocal fold, which has a higher elastin concentration in the deeper layers of the lamina propria, both the pig and the dog had a thin band of elastin concentrated just deep to the basement membrane zone in the superficial layer. Just deep to this thin band, the collagen and the elastin were less concentrated. The monkey vocal fold had a very thin mucosal layer with less elastin throughout the mucosa. The microflap dissections in each of the dog, pig, and human vocal folds were similar, being located within that portion of the superficial lamina propria where the elastin and mature collagen are less concentrated. The microflap plane in the monkey vocal fold was more deeply located near the vocalis fibers. Despite the differences in elastin concentration, the microflap plane in both the dog and the pig was found to be similar to that in humans. The dog anatomy was much more suitable for microsuspension laryngoscopy and stroboscopic examination. The dog vocal folds vibrated in a similar fashion to human vocal folds with mucosal waves and vertical phase differences, features not seen in the pig vocal folds. Conclusions Based on both the histological and stroboscopic results, the dog was believed to be a more suitable animal model for studies on vocal fold surgery, acknowledging that no animal's laryngeal anatomy is identical to that of the human. The dog LVS model presented allows for longitudinal laryngeal studies requiring repeated examinations at multiple time periods with histological correlation applied at sacrifice. [source] Structural and Histochemical Studies on the Teleostean Bulbus ArteriosusANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 6 2009I. L. Leknes Summary The structure and histochemical properties of the bulbus arteriosus in two species from an evolutionary old teleost family, Characidae, and in three modern teleosts, family Cichlidae, are described. The bulbar wall was composed of an outer layer, a middle layer and a strongly folded inner layer covered by a thick, granule-rich endothelial cell layer towards the lumen. One of the cichlid species (Thorichthys meeki) was injected intraperitoneally with horse ferritin; the endothelial cell layer of the heart atrium and ventricle displayed high ability to endocytose ferritin particles from the blood stream, but the corresponding layer in the bulbus arteriosus displayed no such uptake. This finding suggests that the bulbar endothelial cell layer plays no scavenger or immunological blood cleansing roles in this species. The bulbar endothelial cell granules were strongly coloured by periodic acid,Schiff (PAS) in the present cichlids, but weakly coloured by PAS in the present characids. These cell layers were uncoloured by alkaline carmine in ethanol in both cichlids and characids. The negative carmine test combined with a positive PAS test for the bulbar endothelial cell layer in the present cichlids indicates that these cells contain only small amounts of polysaccharides. The weak PAS-colouring for the bulbar endothelial cell layer in characids indicates a very low content of sugars in these cells. These findings together with the fact that this cell layer in the present cichlids and characids was nearly uncoloured when treated with orcein, Heidenhain's Azan or Schmorl's solutions for elastic materials suggest that the bulbar endothelial granules do not play any role in the blood cleansing or in the rebuilding or maintenance of the ground substance or elastic material in the bulbar wall. Probably, the granules in the bulbar endothelial cell layer in the present species contain mainly proteins, connected to some PAS-positive polysaccharides to enhance their solubility. [source] | ||||||||||