Electron microscopic studies of coated membranes in two types of gill epithelial cells of lamprey

1977 ◽  
Vol 178 (3) ◽  
Author(s):  
Taisuke Nakao
Keyword(s):  
Epithelial Cells ◽  
Electron Microscopic ◽  
Coated Membranes ◽  
Microscopic Studies

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.

scholarly journals ELECTRON MICROSCOPY OF THE BURSA OF FABRICIUS OF THE EMBRYONIC CHICK WITH PARTICULAR REFERENCE TO THE LYMPHO-EPITHELIAL NODULES

1962 ◽  
Vol 13 (1) ◽  
pp. 127-146 ◽  
Author(s):  
G. Adolph Ackerman
Keyword(s):  
Endoplasmic Reticulum ◽  
Epithelial Cells ◽  
Embryonic Development ◽  
Golgi Complex ◽  
Bursa Of Fabricius ◽  
Cortical Region ◽  
Electron Microscopic ◽  
Submicroscopic Structure ◽  
Microscopic Studies ◽  
Pass Through

Electron microscopic studies of the bursa of Fabricius during the 15th and 16th day of embryonic development in the chick have shown the following findings in the submicroscopic structure of the cellular elements of the lympho-epithelial follicles. In the medulla, basal endodermal epithelial cells undergo mitosis and differentiation into lymphoblasts. During this transformation, there is a reduction in the amount of rough endoplasmic reticulum, an increase in the number or ribosomes, and frequently an enlargement of the Golgi complex. As lymphoblasts differentiate into medium lymphocytes there is a loss of endoplasmic reticulum, a reduction in the number of ribosomes and in the size of the Golgi complex, as well as a decrease in the number and size of mitochondria and in the size of the cell and nucleus. Cytoplasmic processes of reticular-epithelial cells extend between proliferating lymphocytic cells. Desmosomes connect stellate reticular-epithelial and basal epithelial cells but are not present in lymphocytic cells. Nuclear blebbing and vesiculation are frequently observed in the various cell forms of the developing lympho-epithelial nodules. Although lymphocytes and lymphocytopoietic activities in the cortex are sparse during this stage of embryonic development of the bursa, transitional forms between mesenchymal cells and lymphoblasts have been encountered. In addition, lymphoblasts and/or undifferentiated epithelial cells occasionally may pass through the basement membrane from the medulla into the cortical region of the developing nodule. That lymphocytes in the bursa of Fabricius originate from both endodermal and mesodermal derivatives during embryonic development appears to be consistent with both light and electron microscopic observations.

scholarly journals Illustration of Pneumococcal Polysaccharide Capsule during Adherence and Invasion of Epithelial Cells

2005 ◽  
Vol 73 (8) ◽  
pp. 4653-4667 ◽  
Author(s):  
Sven Hammerschmidt ◽  
Sonja Wolff ◽  
Andreas Hocke ◽  
Simone Rosseau ◽  
Ellruth Müller ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Capsular Polysaccharide ◽  
A549 Cells ◽  
The State ◽  
Fixation Method ◽  
Fixation Procedure ◽  
Pneumococcal Infections ◽  
Electron Microscopic ◽  
Polysaccharide Capsule ◽  
Microscopic Studies

ABSTRACT The capsular polysaccharide of Streptococcus pneumoniae represents an important virulence factor and protects against phagocytosis. In this study the amount of capsular polysaccharide present on the bacterial surface during the infection process was illustrated by electron microscopic studies. After infection of A549 cells (type II pneumocytes) and HEp-2 epithelial cells a modified fixation method was used that allowed visualization of the state of capsule expression. This modified fixation procedure did not require the use of capsule-specific antibodies. Visualization of pneumococci in intimate contact and invading cells demonstrated that pneumococci were devoid of capsular polysaccharide. Pneumococci not in contact with the cells did not show alterations in capsular polysaccharide. After infection of the cells, invasive pneumococci of different strains and serotypes were recovered. Single colonies of these recovered pneumococci exhibited an up-to-105-fold-enhanced capacity to adhere and an up-to-104-fold-enhanced capacity to invade epithelial cells. Electron microscopic studies using a lysine-ruthenium red (LRR) fixation procedure or cryo-field emission scanning electron microscopy revealed a reduction in capsular material, as determined in detail for a serotype 3 pneumococcal strain. The amount of polysaccharide in the serotype 3 capsule was also determined after intranasal infection of mice. This study illustrates for the first time the phenotypic variation of the polysaccharide capsule in the initial phase of pneumococcal infections. The modified LRR fixation allowed monitoring of the state of capsule expression of pathogens during the infectious process.

The Thymus of Spontaneously Hypertensive Rats: Light- and Electron-Microscopic Studies

1973 ◽  
Vol 45 (s1) ◽  
pp. 141s-144s
Author(s):  
J. M. Rojo-Ortega ◽  
E. Yeghiayan ◽  
J. Genest
Keyword(s):  
Epithelial Cells ◽  
Vascular Disease ◽  
Spontaneously Hypertensive Rats ◽  
Plasma Cells ◽  
Vascular Lesions ◽  
Hypertensive Rats ◽  
Electron Microscopic ◽  
Spontaneously Hypertensive ◽  
Microscopic Studies ◽  
Microscopic Techniques

1. The present investigation was undertaken to study the possibility that hypertensive vascular disease could be associated with changes in the morphology of the thymus. 2. Using light- and electron-microscopic techniques, the thymus of spontaneously hypertensive rats (SHR) with (1 year of age) and without (10 weeks of age) severe vascular lesions were compared with appropriate controls. 3. The thymus of SHR with severe hypertensive vascular disease showed: (a) marked hyperplasia and hypertrophy of the epithelial cells, with ultrastructural features of hypersecretory activity, and (b) in contrast to the paucity of plasma cells in the thymus of the control animals, the SHR had numerous plasma cells. 4. These observations may suggest the involvement of an autoimmunological mechanism in the development of the vascular lesions in SHR.

Hyperplasia of Type II Pneumocytes in Pulmonary Lymphangioleiomyomatosis

2000 ◽  
Vol 124 (11) ◽  
pp. 1642-1648 ◽  
Author(s):  
Kazuhiro Matsui ◽  
William K. Riemenschneider ◽  
Stephen L. Hilbert ◽  
Zu-Xi Yu ◽  
Kazuyo Takeda ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Connective Tissue ◽  
Structural Characteristics ◽  
Alveolar Epithelial Cells ◽  
Nuclear Antigen ◽  
Type I ◽  
Type Ii ◽  
Electron Microscopic ◽  
Type Ii Pneumocytes ◽  
Microscopic Studies

Abstract Background.—Little is known of the morphology of the pneumocytes lining the parenchymal cysts in lymphangioleiomyomatosis (LAM). Objective.—To evaluate the structural characteristics of the alveolar epithelial cells in LAM. Methods.—Immunohistochemical and electron microscopic studies were performed on lung tissue from 22 women with pulmonary LAM. Results.—Epithelial cells that reacted with PE-10 (a mouse monoclonal antibody that recognizes the surfactant apoprotein A in type II pneumocytes) and TTF-1 (an antibody that identifies nuclear transcription factor found in type II pneumocytes) were the predominant cell type lining the surfaces of lesions of LAM and normal areas of lung. Scanning and transmission electron microscopic studies confirmed that these cells were type II pneumocytes as demonstrated by (1) apical microvilli, (2) electron-dense lamellar bodies, and (3) cytoplasmic projections that extended from the basal surfaces into the underlying connective tissue, where they made extensive contact with interstitial connective tissue cells. A few cells had morphologic characteristics of type I pneumocytes, including large flat surfaces lacking microvilli. Cells that appeared intermediate between type I and type II pneumocytes were observed occasionally. Conclusions.—These observations and the reactivity of these cells with antibody to proliferating cell nuclear antigen demonstrate that extensive hyperplasia of type II pneumocytes is a major characteristic of LAM.

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