Données nouvelles sur la structure et la minéralisation des écailles d'Anguilla anguilla (Osteichthyes, Anguillidae)

1984 ◽  
Vol 62 (12) ◽  
pp. 2482-2494 ◽  
Author(s):  
Louise Zylberberg ◽  
François J. Meunier ◽  
Françoise Escaig ◽  
Sylvain Halpern
Keyword(s):  
Light And Electron Microscopy ◽  
Anguilla Anguilla ◽  
Structure Characteristic ◽  
External Layer ◽  
Collagen Fibres ◽  
Mineral Phase ◽  
Laminated Structure ◽  
Teleost Scales ◽  
Characteristic Layers ◽  
Acid Mucosubstances

The structure of the scales in Anguilla anguilla was studied by light and electron microscopy and the mineral phase was analyzed by histophysical techniques. Although the scales of the eel are small in size and have a peculiar superficial ornamentation, which consists of a web of mineralized plates, they are composed of the three characteristic layers of the typical elasmoid scale. The discontinuous, superficial outer limiting layer is highly mineralized; in this layer, acid mucosubstances are abundant but collagen fibres are absent. Mineralization in the external layer is not oriented by the network of the thin collagen fibrils. In the basal plate, mineralization is oriented by the thick collagen fibres packed in bundles. The bundles are oriented from the basal part to the surface of the scale but they are not organized in the laminated structure characteristic of most other teleost scales. The mineral phase of the eel is typical of a teleost fish. The peculiar features of the scale in the eel are interpreted here as a discrete example of the phyletical reduction of the dermal skeleton among Actinopterygii.

Light and Electron Microscopy of the Bulbus arteriosus of the European Eel (Anguilla anguilla)

2000 ◽  
Vol 167 (2-3) ◽  
pp. 184-198 ◽  
Author(s):  
José M. Icardo ◽  
Elvira Colvee ◽  
Maria C. Cerra ◽  
Bruno Tota
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Bulbus Arteriosus

Observations with the electron microscope on enameloid formation in the common eel ( Anguilla anguilla ; Teleostei)

1976 ◽  
Vol 194 (1115) ◽  
pp. 253-269 ◽  
Keyword(s):  
Matrix Protein ◽  
Basal Layer ◽  
Tooth Germ ◽  
Anguilla Anguilla ◽  
Cell Types ◽  
Secretory Cells ◽  
Oral Epithelium ◽  
Collagen Fibres ◽  
The Matrix ◽  
Cell Layers

In the eel, the very young tooth germ consisted of an invagination into the oral epithelium, filled with a papilla of mesenchymal cells. The basal layer of the epithelium surrounding the papilla became the inner dental epithelium (i. d. e.). Initially both the i. d. e. and the papilla cells were undifferentiated. Subsequently, the i. d. e. cells and the superficial cells of the papilla differentiated, the latter becoming odontoblasts, and the matrix of cap enameloid was laid down between the two cell layers. Differentiation of the i. d. e. cells and odontoblasts proceeded in parallel, both cell types acquiring the features of secretory cells, namely enlarged nucleoli, abundant rough endoplasmic reticulum, an active Golgi apparatus and numerous vesicles. Confluence of vesicles with the distal cell membranes was observed. These findings indicate that both the i. d. e. and odontoblasts synthesize protein and secrete it into the matrix of cap enameloid, in confirmation of previous studies with autoradiography (Shellis & Miles 1974). The matrix of cap enameloid reached its mature size and shape without becoming mineralized. It contained collagen fibres, odontoblast processes and vesicles. Mineralization of cap enameloid appeared to proceed centrifugally. The crystals were large and ribbon-like, as in enamel, and their orientation conformed with the pattern of collagen fibres of the matrix. The matrix protein, including the fibres, was, however, removed during mineralization, apparently by way of the i. d. e., which showed special features at this stage associated with transport of both protein and mineral. The collar enameloid in this fish was only about 2 μm thick and consisted of two hypermineralized layers. The inner layer appeared to be homologous with the cap enameloid, being formed by the joint activity of odontoblasts and the i. d. e. of Hertwig’s sheath. The outer, more heavily mineralized layer appeared to be produced entirely by the i. d. e. and a similar layer was laid down on the outer surface of the cap enameloid. The teeth of the eel thus bear a layer of enameloid, covered in turn by a much thinner layer which may be homologous with enamel.

Development of a three-dimensional extracellular matrix synthesized by human diploid fibroblasts in vitro

1986 ◽  
Vol 84 (1) ◽  
pp. 183-200
Author(s):  
E.E. Qwarnstrom ◽  
R.C. Page
Keyword(s):  
Extracellular Matrix ◽  
Light And Electron Microscopy ◽  
Root Surface ◽  
Human Tooth ◽  
Immunocytochemical Staining ◽  
Cell Contact ◽  
Collagen Fibres ◽  
Intense Staining ◽  
Fibrillar Material ◽  
The Matrix

Development and maturation of an extracellular matrix, synthesized by human gingival fibroblasts, have been studied microscopically. Pairs of demineralized, fibronectin-coated slices of human tooth root, 300 micron thick, were placed on confluent cell layers, defining a 0.5 mm wide space. The cultures were grown under standard conditions with ascorbic acid (50 micrograms ml-1) added daily. At various times up to 13 weeks, the cultures were fixed and the samples prepared for light and electron microscopy. Cells from the monolayer became attached to, and migrated up, the vertical root surface and, during the time studied, completely filled the space between the root slices with an extracellular matrix. A close association was seen between the cell membrane and collagen fibres in the demineralized surface initially. A thin layer of fibrillar material was deposited between the cell and the vertical surface, and eventually an extracellular matrix surrounding the cells and attaching to the root surface was present. Samples fixed in the presence of Ruthenium Red showed intense staining of the fibrillar material, indicating the presence of anionic molecules. Additional cells migrated onto the newly synthesized matrix and up the root surface. Growth of the fibrillar networks on either side, horizontally and vertically, continued and, eventually, an extracellular matrix attaching to the vertical surfaces completely filled the previously empty space. Immunocytochemical staining showed that the matrix contained hyaluronic acid, chondroitin sulphate, dermatan sulphate and fibronectin at this time. Collagen fibres were observed at 6 weeks, and at later times collagen types I, III and V were the primary matrix components. The fibroblasts attaching to the root slice and those present at the edge of the matrix had an elongated, polar form. The cells within the matrix frequently showed a stellate appearance with numerous extended processes, in contact with fibrillar material or collagen fibres. Fibroblast processes were at later times seen to enclose bundles of collagen fibres and to mediate cell-to-cell contact, occasionally via desmosome-like structures. The structure and composition of the matrix and the appearance and apparent behaviour of the cells were similar to that observed in the healing wound. This system thus could provide a model for studying various aspects of regeneration of extracellular matrix.

The Morphology of Vacuolated Cells in the Liver Following Administration of Vitamin A.

1973 ◽  
Vol 31 ◽  
pp. 408-409
Author(s):  
Odell T. Minick ◽  
Hidejiro Yokoo ◽  
Fawzia Batti
Keyword(s):  
Electron Microscopy ◽  
Body Weight ◽  
Vitamin A ◽  
Light And Electron Microscopy ◽  
Liver Cells ◽  
Prominent Feature ◽  
Vascular Space ◽  
Vacuolated Cell ◽  
Vacuolated Cells ◽  
Vacuolated Cytoplasm

Vacuolated cells in the liver of young rats were studied by light and electron microscopy following the administration of vitamin A (200 units per gram of body weight). Their characteristics were compared with similar cells found in untreated animals.In rats given vitamin A, cells with vacuolated cytoplasm were a prominent feature. These cells were found mostly in a perisinusoidal location, although some appeared to be in between liver cells (Fig. 1). Electron microscopy confirmed their location in Disse's space adjacent to the sinusoid and in recesses between liver cells. Some appeared to be bordering the lumen of the sinusoid, but careful observation usually revealed a tenuous endothelial process separating the vacuolated cell from the vascular space. In appropriate sections, fenestrations in the thin endothelial processes were noted (Fig. 2, arrow).

Freeze-etch studies of epiphyseal growth plate cartilage reveal matrix vesicles associated with calcification

1978 ◽  
Vol 36 (2) ◽  
pp. 670-671
Author(s):  
Russell N. A. Cecil ◽  
H. Clarke Anderson
Keyword(s):  
Chromic Acid ◽  
Light And Electron Microscopy ◽  
Matrix Vesicles ◽  
Matrix Vesicle ◽  
Glycerol Solution ◽  
Sprague Dawley ◽  
Epiphyseal Growth Plate ◽  
Growth Plates ◽  
Sprague Dawley Rats ◽  
Tibial Epiphyseal

Unfixed proximal tibial epiphyseal growth plates were studied by freeze-etch to confirm the presence of extracellular calcifying matrix vesicles and to determine the substructure of matrix vesicle membranes as compared to plasma and other membranes of intact chondrocytes. Growth plates from 6-10 week old Sprague-Dawley rats were cut into 1x3 mm blocks whose long dimension was oriented either perpendicular or parallel to the long axis of the tibia. Some blocks were fixed at pH 7. 0 in 0. 2M cacodylate - buffered 2. 5% glutaraldehyde for 1 hour at 4ÅC. The blocks were immersed in 30% glycerol solution at 4ÅC for 1 hour, frozen in liquid nitrogen, and then fractured, etched for 2 minutes, and coated with platinum, carbon and 0. 2% Formvar solution. The replicas were cleaned with chromic acid, floated onto Formvar coated grids, and examined with a Phillips EM 300 electron microscope.Fixed and unfixed specimens appeared similar in ultrastructure. Chondrocytes, matrix, and matrix vesicles were identified. In specimens fractured parallel to the long axis of the tibia, the reserve, proliferative, hypertrophic, and calcifying zones could be discerned as described by light and electron microscopy.

Altered thymic epithelial cells may be decisive for Moloney virus-induced lymphoma development

1983 ◽  
Vol 41 ◽  
pp. 784-785
Author(s):  
U.I. Heine ◽  
G.R.F. Krueger ◽  
E. Munoz ◽  
A. Karpinski
Keyword(s):  
Epithelial Cells ◽  
Leukemia Virus ◽  
Light And Electron Microscopy ◽  
Tumor Development ◽  
Current Evidence ◽  
Thymic Epithelial Cells ◽  
Thymic Tissue ◽  
Newborn Mice ◽  
Moloney Leukemia Virus ◽  
Differentiation Block

Infection of newborn mice with Moloney leukemia virus (M-MuLV) causes a T-cell differentiation block in the thymic cortex accompanied by proliferation and accumulation of prethymic lymphoblasts in the thymus and subsequent spreading of these cells to generate systemic lymphoma. Current evidence shows that thymic reticular epithelial cells (REC) provide a microenvironment necessary for the maturation of prethymic lymphoblasts to mature T-lymphocytes by secretion of various thymic factors. A change in that environment due to infection of REC by virus could be decisive for the failure of lymphoblasts to mature and thus contribute to lymphoma development.We have studied the morphology and distribution of the major thymic cell populations at different stages of tumorigenesis in Balb/c mice infected when newborn with 0.2ml M-MuLV suspension, 6.8 log FFU/ml. Thymic tissue taken at 1-2 weekly intervals up to tumor development was processed for light and electron microscopy, using glutaraldehyde-OsO4fixation and Epon-Araldite embedding.

Structural Organization and Distribution of Fiber Types in Extraocular Muscles of Cats

1972 ◽  
Vol 30 ◽  
pp. 34-35
Author(s):  
Asish C. Nag ◽  
Lee D. Peachey
Keyword(s):  
Fiber Type ◽  
Light And Electron Microscopy ◽  
Small Diameter ◽  
Extraocular Muscles ◽  
Fiber Types ◽  
Distinctive Features ◽  
Superior Rectus ◽  
Adult Cats ◽  
Different Diameters ◽  
Orbital Region

Cat extraocular muscles consist of two regions: orbital, and global. The orbital region contains predominantly small diameter fibers, while the global region contains a variety of fibers of different diameters. The differences in ultrastructural features among these muscle fibers indicate that the extraocular muscles of cats contain at least five structurally distinguishable types of fibers.Superior rectus muscles were studied by light and electron microscopy, mapping the distribution of each fiber type with its distinctive features. A mixture of 4% paraformaldehyde and 4% glutaraldehyde was perfused through the carotid arteries of anesthetized adult cats and applied locally to exposed superior rectus muscles during the perfusion.

Effects of EDTA, Hyaluronidase and Collagenase on Epiphyseal Cartilage Matrix

1968 ◽  
Vol 26 ◽  
pp. 56-57
Author(s):  
H. Clarke Anderson ◽  
Priscilla R. Coulter
Keyword(s):  
Light And Electron Microscopy ◽  
Matrix Vesicles ◽  
Cartilage Matrix ◽  
Collagen Fibrils ◽  
Epiphyseal Cartilage ◽  
Dense Matrix ◽  
Type Iv ◽  
Bovine Testicular Hyaluronidase ◽  
The Matrix ◽  
Testicular Hyaluronidase

Epiphyseal cartilage matrix contains fibrils and particles of at least 5 different types: 1. Banded collagen fibrils, present throughout the matrix, but not seen in the lacunae. 2. Non-periodic fine fibrils <100Å in diameter (Fig. 1), which are most notable in the lacunae, and may represent immature collagen. 3. Electron dense matrix granules (Fig. 1) which are often attached to fine fibrils and collagen fibrils, and probably contain protein-polysaccharide although the possibility of a mineral content has not been excluded. 4. Matrix vesicles (Fig. 2) which show a selective distribution throughout the epiphysis, and may play a role in calcification. 5. Needle-like apatite crystals (Fig. 2).Blocks of formalin-fixed epiphysis from weanling mice were digested with the following agents in 0.1M phosphate buffer: a) 5% ethylenediaminetetraacetate (EDTA) at pH 8.3, b) 0.015% bovine testicular hyaluronidase (Sigma, type IV, 750 units/mg) at pH 5.5, and c) 0.1% collagenase (Worthington, chromatograhically pure, 200 units/mg) at pH 7.4. All digestions were carried out at 37°C overnight. Following digestion tissues were examined by light and electron microscopy to determine changes in the various fibrils and particles of the matrix.

Control of Autogenous Vein Grafts Prior to Reimplantation, By Electron Microscopy

1972 ◽  
Vol 30 ◽  
pp. 106-107
Author(s):  
John H. L. Watson ◽  
John L. Swedo ◽  
M. Vrandecic
Keyword(s):  
Electron Microscopy ◽  
Light And Electron Microscopy ◽  
Physiological Saline ◽  
Experimental Conditions ◽  
Vein Grafts ◽  
Arterial Blood ◽  
Saphenous Veins ◽  
Autogenous Vein ◽  
Control Of Parameters ◽  
Post Implantation

The ambient temperature and the nature of the storage fluids may well have significant effects upon the post-implantation behavior of venus autografts. A first step in the investigation of such effects is reported here. Experimental conditions have been set which approximate actual operating room procedures. Saphenous veins from dogs have been used as models in the experiments. After removal from the dogs the veins were kept for two hours under four different experimental conditions, viz at either 4°C or 23°C in either physiological saline or whole canine arterial blood. At the end of the two hours they were prepared for light and electron microscopy. Since no obvious changes or damage could be seen in the veins by light microscopy, even with the advantage of tissue specific stains, it was essential that the control of parameters for successful grafts be set by electron microscopy.

Ultrastructure of two neoplasms in culture compared with original biopsies

1984 ◽  
Vol 42 ◽  
pp. 50-51
Author(s):  
Joseph M. Harb ◽  
James T. Casper ◽  
Vlcki Piaskowski
Keyword(s):  
Electron Microscopy ◽  
Tissue Culture ◽  
Biopsy Specimen ◽  
Cultured Cells ◽  
Light And Electron Microscopy ◽  
Human Tumor ◽  
Soft Agar ◽  
Human Tumor Cells ◽  
Morphological Distinction ◽  
Tumor Types

The application of tissue culture and the newer methodologies of direct cloning and colony formation of human tumor cells in soft agar hold promise as valuable modalities for a variety of diagnostic studies, which include morphological distinction between tumor types by electron microscopy (EM). We present here two cases in which cells in culture expressed distinct morphological features not apparent in the original biopsy specimen. Evaluation of the original biopsies by light and electron microscopy indicated both neoplasms to be undifferentiated sarcomas. Colonies of cells propagated in soft agar displayed features of rhabdomyoblasts in one case, and cultured cells of the second biopsy expressed features of Ewing's sarcoma.

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