Scanning electron microscopic study of collagen fibrillogenesis and extracellular compartmentalization in the chick embryo tendon

1986 ◽  
Vol 44 ◽  
pp. 208-209
Author(s):  
Grace C.H. Yang
Keyword(s):  
Chick Embryo ◽  
Extracellular Space ◽  
Fibroblast Cell ◽  
Collagen Fibrils ◽  
Electron Microscopic ◽  
Voltage Electron ◽  
Scanning Electron Microscopic Study ◽  
Microscopic Studies ◽  
And Function

The size and organization of collagen fibrils in the extracellular matrix is an important determinant of tissue structure and function. The synthesis and deposition of collagen involves multiple steps which begin within the cell and continue in the extracellular space. High-voltage electron microscopic studies of the chick embryo cornea and tendon suggested that the extracellular space is compartmentalized by the fibroblasts for the regulation of collagen fibril, bundle, and tissue specific macroaggregate formation. The purpose of this study is to gather direct evidence regarding the association of the fibroblast cell surface with newly formed collagen fibrils, and to define the role of the fibroblast in the control and the precise positioning of collagen fibrils, bundles, and macroaggregates during chick tendon development.

Role of cell adhesion in contact-dependent transfer of a lysosomal enzyme from lymphocytes to fibroblasts

1986 ◽  
Vol 85 (1) ◽  
pp. 231-244
Author(s):  
I. Olsen ◽  
T. Oliver ◽  
H. Muir ◽  
R. Smith ◽  
T. Partridge
Keyword(s):  
Lysosomal Enzyme ◽  
Plasma Membranes ◽  
Fibroblast Cell ◽  
Active Role ◽  
Electron Microscopic ◽  
High Frequencies ◽  
Transmission Electron ◽  
Cell Enzyme ◽  
Microscopic Studies

Normal lymphocytes were found to adhere strongly to monolayer cultures of fibroblasts deficient in the lysosomal enzyme, beta-glucuronidase. During this co-culture, the fibroblasts acquired from the lymphocytes substantial amounts of this enzyme, which often accumulated at sites of contact between the two types of cell. Enzyme transfer was prevented by addition to the co-cultures either of purified lymphocyte plasma membranes or of antibody raised against such plasma membranes, but it was not inhibited by the addition of antibody raised against lymphocyte-derived beta-glucuronidase. An active role for the lymphocyte in this contact-dependent process was suggested by interference contrast, immunofluorescence and scanning electron-microscopic studies. These revealed extensive arrays of projections of the lymphocyte that ramified over the fibroblast cell surface. By transmission electron microscopy, conspicuous clusters of micropinocytotic vesicles were evident in the cytoplasm of the ‘recipient’ fibroblasts, subjacent to the surface in regions closely apposed to adherent lymphocytes. Such high frequencies of these vesicles were restricted to sites of lymphocyte-fibroblast contact, suggesting that they may play an important part in the transfer of enzyme between these two types of cell.

The Microenvironment of Neurons

1970 ◽  
Vol 28 ◽  
pp. 136-137
Author(s):  
William Bondareff
Keyword(s):  
Electron Micrographs ◽  
Extracellular Space ◽  
Brain Volume ◽  
Freeze Substitution ◽  
Electron Microscopic ◽  
Morphological Studies ◽  
Microscopic Studies ◽  
Distribution Composition ◽  
And Function ◽  
The Brain

Neurons in the central nervous system are separated by extracellular spaces, the distribution, composition and function of which are not unequivocally known. Earlier electron microscopic studies of chemically-fixed tissues demonstrated extracellular spaces composed of uniformly narrow, apparently empty channels constituting 3-5% of the brain volume. The results of more recent morphological and non-morphological studies support the existence of less uniform intercellular channels, varying in dimension from 100 Å to almost 1 μ, and constituting 20-25% of the brain volume. Although this space is not revealed in electron micrographs of chemicallyfixed nervous tissues, it is demonstrated readily in specimens fixed by freeze-drying or freeze-substitution (Fig. 1). The dynamic nature of those extracellular spaces, as visualized in electron micrographs of nervous tissue fixed by freeze-substitution, was demonstrated in studies of normalbrain maturation. An extracellular space of 40% became gradually smaller as development proceeded to reach the smaller extracellular space characteristic of mature animals.

Stannous fluoride treatment of acid-etched caries-like lesions of enamel: A scanning electron microscopic study

1984 ◽  
Vol 42 ◽  
pp. 720-721
Author(s):  
M. John Hicks ◽  
Leon M. Silverstone ◽  
David G. Gantt ◽  
Catherine M. Flaitz
Keyword(s):  
Acid Etching ◽  
Surface Zone ◽  
Electron Microscopic ◽  
Fluoride Treatment ◽  
Stannous Fluoride ◽  
Scanning Electron Microscopic Study ◽  
Demineralized Enamel ◽  
Intact Surface ◽  
Topical Fluoride

Although fluoride levels become elevated in sound enamel following a topical fluoride treatment, the caries-preventive effect of fluoride is thought to be due primarily to the role of fluoride in remineralization of clinically undetectable enamel lesions and hypomineralized enamel. During lesion formation, redistribution of fluoride from the enamel surface to the subsurface demineralized enamel occurs. This results in a surface zone with a relatively low fluoride content. In order to maintain an intact surface zone over a carious lesion, it may be necessary to replenish the fluoride levels with an exogenous fluoride source. By acid-etching the lesion surface, a more reactive surface is made available for fluoride interaction. In addition, porosities and etching patterns may be created, allowing for bonding of a caries-resistant resin material to the lesion surface. The purpose of this study was to determine the integrity of the caries-like lesion surface following acid-etching and subsequent stannous fluoride treatment (SnF2).

A Scanning Electron Microscopic Study of the Normal Human Stapes

1979 ◽  
Vol 88 (6_suppl4) ◽  
pp. 2-14 ◽  
Author(s):  
Malcolm D. Graham ◽  
Rodney Perkins
Keyword(s):  
Microscopic Study ◽  
Electron Microscopic Study ◽  
Electron Microscopic ◽  
Scanning Electron Microscopic Study ◽  
Scanning Electron Microscopic ◽  
Microscopic Features ◽  
Microscopic Studies ◽  
Normal Human ◽  
Temporal Bones ◽  
Scanning Electron

The structure of the normal human stapes was studied with the scanning electron microscope. Specimens were obtained 48 hours after death from adult human temporal bones free from obvious inflammatory disease. The specimens were fixed, dissected, critical-point dried and coated with gold. In this scanning electron microscopic study an attempt has been made to systematically demonstrate the average scanning electron microscopic features of various areas of the normal human stapes. An emphasis has been placed upon demonstrating as clearly as possible the details previously unclear or unrecognized and duplication of many excellent earlier light and electron microscopic studies has not been attempted. The typical appearance of the stapes head, neck, arch, crura and footplate has been presented. It is apparent that there exists a high degree of structural specialization particularly in the stapes arch and footplate area.

Mise en évidence du rôle, dans la régénération des Amphibiens, d'une glycoprotéine sécrétée par la cape apicale: étude cytochimique et autoradiographique en microscopie électronique

Development ◽  
1974 ◽  
Vol 32 (1) ◽  
pp. 133-145
Author(s):  
Par Claude Chapron
Keyword(s):  
High Resolution ◽  
Epithelial Cells ◽  
Limb Regeneration ◽  
Target Cells ◽  
Silver Particles ◽  
Electron Microscopic ◽  
Microscopic Studies ◽  
High Resolution Autoradiography

Evidence for the role of an apical cap glycoprotein in amphibian regeneration: cytochemical and autoradiographic electron-microscopic studies Early during limb regeneration in the newt, an ectodermal apical cap covering a mesodermal blastema is formed. High-resolution autoradiography of these tissues has been carried out after incorporation of [3H]fucose, which is a precursor of glycoproteins. Autoradiography shows that silver particles are located at first on epithelial cells, then on mesenchymatous cells. This observation is consistent with a hypothesis in which the apical cap would elaborate a glycoprotein acting on the blastema. Substructural autoradiography and cytochemistry also show the importance of cellular surfaces for both cells producing glycoprotein and those which are target cells.

Polarized pigment granule transport occurs in the absence of microtubules in squirrelfish erythrophores: studies of the effects of estramustine

1987 ◽  
Vol 87 (4) ◽  
pp. 565-580
Author(s):  
M.E. Stearns ◽  
M. Wang
Keyword(s):  
Pigment Granule ◽  
Electron Microscopic ◽  
Microtubule Associated Proteins ◽  
Voltage Electron ◽  
Associated Proteins ◽  
Drug Inhibition ◽  
Microscopic Studies ◽  
10 Nm Filaments ◽  
Inhibition Studies

We have re-examined the involvement of microtubules in the process of pigment granule transport in squirrelfish erythrophores in situ (i.e. on scales). Light-microscopic studies revealed that following exposure to 5 microM-nocodazole for 1 h at 4 degrees C erythrophores retained an ability to aggregate and disperse their pigment uniformly, though at reduced rates. Serial thick-section stereo high-voltage electron-microscopic studies showed that the entire microtubule population was removed by drug treatment and that the microtubules were not reassembled as a result of pigment translocation processes in the presence of reduced levels of nocodazole (0.4 microM). Immunofluorescence microscopic studies confirmed that nocodazole (0.5-1 microM) produced rapid disassembly of the microtubules. Whole-mount electron-microscopic studies showed that the pigment granules were suspended in a cross-linking network of 3–10 nm filaments, which appeared to support ordered pigment transport in situ in the absence of microtubules. Drug inhibition studies showed that micromolar levels of estramustine, a novel anti-MAPs (microtubule-associated proteins) drug, reversibly inhibited pigment transport. The results suggest that an estramustine-sensitive cytomatrix component might produce polarized pigment transport in intact erythrophores.

Study of interaction and adsorption of aromatic amines by manganese oxides and their role in chemical evolution

2016 ◽  
Vol 16 (2) ◽  
pp. 143-155 ◽  
Author(s):  
Brij Bhushan ◽  
Arunima Nayak ◽  
Kamaluddin
Keyword(s):  
Aromatic Amines ◽  
Manganese Oxides ◽  
Oxidation Products ◽  
Gas Chromatography Mass Spectrometry ◽  
Spectroscopy Analysis ◽  
Electron Microscopic ◽  
Microscopic Studies ◽  
The Fourier Transform ◽  
Langmuir Constants

AbstractThe role of manganese oxides in concentrating organic moieties and offering catalytic activity for prebiotic reactions is investigated by studying their interaction with different aromatic amines such as aniline, p-chloroaniline, p-toluidine and p-anisidine. For all amines, metal oxides showed highest adsorption at neutral pH. The order of their adsorption capacity and affinity as revealed by the Langmuir constants was found to be manganosite (MnO) > bixbyite (Mn2O3) > hausmannite (Mn3O4) > and pyrolusite (MnO2). At alkaline pH, these manganese oxides offered their surfaces for oxidation of amines to form coloured oligomers. Analysis of the oxidation products by gas chromatography–mass spectrometry showed the formation of a dimer from p-anisidine and p-chloroaniline, while a trimer and tetramer is formed from p-toluidine and aniline, respectively. A reaction mechanism is proposed for the formation of the oligomers. While field-emission scanning electron microscopic studies confirm the binding phenomenon, the Fourier transform infrared spectroscopy analysis suggests that the mechanism of binding of amines on the manganese oxides was primarily electrostatic. The adsorption behaviour of the studied aromatic amines followed the order: p-anisidine > p-toluidine > aniline > p-chloroaniline, which is related to the basicities and structure of the amines. Our studies confirmed the significance of the role of manganese oxides in prebiotic chemistry.

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