Search results for "Microscopy"
showing 10 items of 3390 documents
Light and electron microscopical demonstration of methylene blue accumulation sites in taste buds of fish and mouse after supravital dye injection
1995
Electron microscopical data regarding methylene blue staining of taste buds in the epithelia of the goldfish lip and the cirumvallate papilla of the mouse tongue after supravital dye application are presented for the first time. The ultrastructural details were compared with the corresponding light microscopical findings. The dye was applied in different concentrations by injection or in crystalline from directly to the surface of the tissues. Both methylene blue and tissue were simultaneously fixed by immersion in a paraformaldehyde-glutaraldehyde solution with the addition of phosphomolybdic acid. The ensuing dye precipitate was further stabilized by ammonium heptamolybdate. On the light …
Immunohistochemistry of cholinergic receptors.
1992
Acetylcholine and its receptors are involved in a variety of important signal transduction processes. As shown here paradigmatically for the human neuromuscular junction and the cerebral cortex, acetylcholine receptors can be visualized immunohistochemically at the cellular and subcellular level under physiological and pathological conditions. At normal motor endplates nicotinic cholinoceptors are localized at the surface of the postsynaptic junctional folds. In myasthenic syndromes investigation of muscle biopsies enables the diagnosis of receptor deficiencies at the ultrastructural level. In normal cerebral cortex pyramidal neurons are equipped with both nicotinic and muscarinic acetylcho…
The pia mater at the site of the entry of blood vessels into the central nervous system
1982
The entry of blood vessels into the central nervous system (CNS) has been studied at the surface of the brain stem and the spinal cord of two cats and two rabbits. The study was carried out by scanning electron microscopy (SEM). The results obtained by SEM concerning the layers of the pia mater corresponded to those obtained by other authors who used transmission electron microscopy. Between the basal lamina of the superficial glial membrane of the CNS and the cells lining the subarachnoid space, a pial connective tissue space could be clearly recognized. The blood vessles crossing the subarachnoid space were also covered by leptomeningeal lining cells. At the site of entry of these blood v…
Quantitative electron microscopic observations on Paneth cells of germfree and ex-germfree Wistar rats.
1986
Ultrastructural changes of Paneth cells of germfree (Gf) rats which had been inoculated with bacteria-containing feces from conventionally-reared (SPF) rats were quantitatively examined. 12 and 24 h after inoculation, the Paneth cells showed a striking decrease in the number of secretory granules and the occurrence of large vacuoles. Phagosomes containing bacteria were not seen. After 4 days, the secretory granules reaccumulated and smooth-surfaced apical vesicles increased in number. It is discussed that the large vacuoles may be related to membrane-retrieval events following the massive extrusion of secretory granules whereas the apical vesicles appear to serve this function when exocytos…
Interaction between mesenchymal cells and the posterior iris epithelium in chicken embryos
1977
The iris anlage of 3--10 day old chicken embryos was studied by both light and electron microscopy. Serial semithin sections showed that some of the mesenchymal cells overlying the eye cup moved into the primitive eye cavity by the 3rd day of incubation. On the 4th day some of these cells came into close contact with the basement membrane of the dorsal iris epithelium. The bases of the epithelial cells were flat at this stage. Towards the 10th day they formed cytoplasmic processes which did not penetrate the basement membrane. Fine mesenchymal cytoplasmic processes and a large number of extracellular fibrils developed in the epithelial--mesenchymal interface. The fine mesenchymal processes …
Effects of acids used in the microabrasion technique: microhardness and confocal microscopy analysis
2015
Background: This study evaluated the effects of the acids used in the microabrasion on enamel. Material and Methods: Seventy enamel/dentine blocks (25 mm 2 ) of bovine incisors were divided into 7 groups (n=10). Experimental groups were treated by active/passive application of 35% H 3 PO 4 (E1/E2) or 6.6% HCl (E3/ E4). Control groups were treated by microabrasion with H 3 PO 4 +pumice (C5), HCl+silica (C6), or no treatment (C7). The superficial (SMH) and cross-sectional (CSMH; depths of 10, 25, 50, and 75 μm) microhardness of enamel were analyzed. Morphology was evaluated by confocal laser-scanning microscopy (CLSM). Data were analyzed by analysis of variance (Proc Mixed), Tukey, and Dunnet…
Reversible neural stem cell niche dysfunction in a model of multiple sclerosis
2011
Objective The subventricular zone (SVZ) of the brain constitutes a niche for neural stem and progenitor cells that can initiate repair after central nervous system (CNS) injury. In a relapsing-remitting model of experimental autoimmune encephalomyelitis (EAE), the neural stem cells (NSCs) become activated and initiate regeneration during acute disease, but lose this ability during the chronic phases of disease. We hypothesized that chronic microglia activation contributes to the failure of the NSC repair potential in the SVZ. Methods Using bromodeoxyuridine injections at different time points during EAE, we quantified the number of proliferating and differentiating progenitors, and evaluate…
Persistent inflammation alters the function of the endogenous brain stem cell compartment
2008
Endogenous neural stem/precursor cells (NPCs) are considered a functional reservoir for promoting tissue homeostasis and repair after injury, therefore regenerative strategies that mobilize these cells have recently been proposed. Despite evidence of increased neurogenesis upon acute inflammatory insults (e.g. ischaemic stroke), the plasticity of the endogenous brain stem cell compartment in chronic CNS inflammatory disorders remains poorly characterized. Here we show that persistent brain inflammation, induced by immune cells targeting myelin, extensively alters the proliferative and migratory properties of subventricular zone (SVZ)-resident NPCs in vivo leading to significant accumulation…
Face-selective adhesion of calcium oxalate dihydrate crystals to renal epithelial cells
1996
The interaction between the most common urinary crystal, calcium oxalate dihydrate (COD) and the surface of monkey renal epithelial cells of the BSC-1 line was investigated. The [100] face of exogenous COD crystals bound selectively and rapidly to the kidney cell surface. Cellular processes extended preferentially over the [100] face initially, and then progressively covered the crystal so that by 24 hours some crystals were observed beneath the plasma membrane. When nucleated from solution onto the surface of the cell monolayer, COD crystals oriented preferentially so that their [100] faces were in direct contact with the cell surface. In contrast, when siliconized glass was used as a subs…
Hsa-miR-30d, secreted by the human endometrium, is taken up by the pre-implantation embryo and might modify its transcriptome.
2015
During embryo implantation, the blastocyst interacts with and regulates the endometrium, and endometrial fluid secreted by the endometrial epithelium nurtures the embryo. Here, we propose that maternal microRNAs (miRNAs) might act as transcriptomic modifier of the pre-implantation embryo. Microarray profiling revealed that six of 27 specific, maternal miRNAs were differentially expressed in the human endometrial epithelium during the window of implantation – a brief phase of endometrial receptivity to the blastocyst – and were released into the endometrial fluid. Further investigation revealed that hsa-miR-30d, the expression levels of which were most significantly upregulated, was secreted…