Search results for "Microscopy"
showing 10 items of 3390 documents
Chromogranin A in the Mammalian Merkel Cell: Cellular and Subcellular Distribution
1989
Chromogranin-A (CGA), which accounts for more than half the soluble matrix protein in secretory granules of various neuroendocrine cells, has a wide spectrum of potential biological roles and is considered an important marker of the diffuse neuroendocrine system (DNES). Light and electron microscopic immunohistochemistry of mammalian skin revealed that Merkel cells are exclusively CGA-immunoreactive (ir) and that the immunoreaction is localized in the secretory granules. This finding supports the classification of the Merkel cell as a member of the DNES. The CGA immunoreactivity was restricted to Merkel cells of pigs and humans. In human embryonic skin, CGA was expressed in Merkel cells as …
The Use of Electron Microscopy and Stereology in the Study of the Mammalian Pineal Gland
1983
Now that transmission electron microscopy (TEM) has been used for many years to study the pineal gland it is timely to evaluate what progress has been achieved by using this technique and to speculate which aspects of pineal research may benefit most by its application in the future.
Trisomy 12 and translocation (7;9) in an ovarian immature teratoma.
1989
We report a case of an immature malignant ovarian teratoma with peritoneal implants diagnosed in an 18-year-old woman. The tumor was brought into remission after surgery (three laparotomies) and adjuvant chemotherapy. A residual peritoneal implant showed a mature epithelial and glial configuration. Histologically, the neuroectodermal component was dominant in the original tumor as well as in the metastases, being confirmed by immunohistochemistry and electron microscopy. A stem cell line has been obtained with cell culture, having a germ cell character and a yolk sac configuration. This line possessed a trisomy 12 and a translocation (7;9) similar to other chromosomal abnormalities describe…
Protection of islets in culture by delivery of oxygen binding neuroglobin via protein transduction.
2005
Islet transplantation has become an accepted method to treat type 1 diabetes. To succeed and achieve normal levels of glucose in transplant recipients, the quality of the transplanted islets is of the utmost importance. Lack of oxygen during organ procurement, islet isolation, and subsequent culture triggers apoptosis or necrosis and loss of islet function, causing the yield and quality to diminish. A promising candidate for cytoprotection against oxygen deprivation is neuroglobin (Ngb). Ngb is a recently described member of globin family and is expressed in neurons, retina, and pancreatic islets. To overexpress this protein in the islets and study its ability to protect them, we utilized p…
Forensic tools for the diagnosis of electrocution death: Case study and literature review
2018
Diagnosis of death by electrocution may be difficult when electric marking is not visible or unclear. Accordingly, the body of a man who appeared to have died from accidental electrocution was carefully forensically analysed. Macroscopic and microscopic analysis of the current mark was carried out using a variable-pressure scanning electron microscope equipped with energy dispersive X-ray microanalyser to highlight skin metallisation, indicating the presence of iron and zinc. The histological findings of electrocution myocardial damage were supported by the results of biochemical analysis which demonstrated the creatine kinase-MB and cardiac troponin I elevation. The effects of electric cu…
Eumelanin Coating of Silica Aerogel by Supercritical Carbon Dioxide Deposition of a 5,6-Dihydroxyindole Thin Film
2018
Eumelanin integration in silica aerogel (SA) was achieved via supercritical adsorption of 5,6-dyhydroxyindole (DHI) from CO2. Notably, after the supercritical treatment, DHI evolved towards spontaneous polymerization, which resulted in uniform pigment development over the SA. The new material was characterized for its morphological and physicochemical properties, disclosing the formation of a eumelanin-like coating, as confirmed by UV&ndash
Effect of air-absorbed oxygen and moisture on the chemical stability of photoexcitedMg,ZnandEuphthalocyanines in dimethylformamide
2006
Absorption of oxygen and moisture from air by MPc-DMF systems was studied and related to the molecular stability demonstrated by phthalocyanine complexes (unsubstituted MPc's : MgPc , ZnPc and EuPc2; Pc = phthalocyanine ligand, C32H16N8) subjected to UV irradiation. A lower stability of air-exposed dimethylformamide solutions is observed and is due to a specific affinity for molecular oxygen revealed by the Pc macrocycle. SEM results proved oxygen molecules fixed to the phthalocyanine solids by forces strong enough to sustain desorption under vacuum. Absorption curves determined for MPc-DMF systems also indicate oxygen accommodated by the phthalocyanine moiety. This explains the predominant…
Glial Chloride Homeostasis Under Transient Ischemic Stress
2021
High water permeabilities permit rapid adjustments of glial volume upon changes in external and internal osmolarity, and pathologically altered intracellular chloride concentrations ([Cl–]int) and glial cell swelling are often assumed to represent early events in ischemia, infections, or traumatic brain injury. Experimental data for glial [Cl–]int are lacking for most brain regions, under normal as well as under pathological conditions. We measured [Cl–]int in hippocampal and neocortical astrocytes and in hippocampal radial glia-like (RGL) cells in acute murine brain slices using fluorescence lifetime imaging microscopy with the chloride-sensitive dye MQAE at room temperature. We observed s…
Integrin-mediated Cell Adhesion to Type I Collagen Fibrils
2004
In the integrin family, the collagen receptors form a structurally and functionally distinct subgroup. Two members of this subgroup, α1β1 and α2β1 integrins, are known to bind to monomeric form of type I collagen. However, in tissues type I collagen monomers are organized into large fibrils immediately after they are released from cells. Here, we studied collagen fibril recognition by integrins. By an immunoelectron microscopy method we showed that integrin α2I domain is able to bind to classical D-banded type I collagen fibrils. However, according to the solid phase binding assay, the collagen fibril formation appeared to reduce integrin α1I and α2I domain avidity to collagen and to lower …
Bio-orthogonal Red and Far-Red Fluorogenic Probes for Wash-Free Live-Cell and Super-resolution Microscopy
2021
Small-molecule fluorophores enable the observation of biomolecules in their native context with fluorescence microscopy. Specific labeling via bio-orthogonal tetrazine chemistry combines minimal label size with rapid labeling kinetics. At the same time, fluorogenic tetrazine–dye conjugates exhibit efficient quenching of dyes prior to target binding. However, live-cell compatible long-wavelength fluorophores with strong fluorogenicity have been difficult to realize. Here, we report close proximity tetrazine–dye conjugates with minimal distance between tetrazine and the fluorophore. Two synthetic routes give access to a series of cell-permeable and -impermeable dyes including highly fluorogen…