scholarly journals STUDIES ON INFLAMMATION

1961 ◽  
Vol 11 (3) ◽  
pp. 571-605 ◽  
Author(s):  
G. Majno ◽  
G. E. Palade
Keyword(s):  
Endothelial Cells ◽  
Electron Microscope ◽  
Basement Membrane ◽  
Blood Vessels ◽  
Electron Micrographs ◽  
Light Microscope ◽  
Intercellular Junctions ◽  
Supporting Evidence ◽  
Electron Microscopic ◽  
Tracer Particles

The mechanism, whereby histamine and serotonin increase the permeability of blood vessels, was studied in the rat by means of the electron microscope. The drugs were injected subcutaneously into the scrotum, whence they diffused into the underlying (striated) cremaster muscle. An intravenous injection of colloidal HgS was also given, in order to facilitate the identification of leaks by means of visible tracer particles. After intervals varying from 1 minute to 57 days the animals were killed; the cremaster was fixed, embedded in methacrylate, and examined with the electron microscope. One to 12 minutes after the injection, the blood vessels of the smallest caliber (3 to 5 micra as measured on electron micrographs) appeared intact. Numerous endothelial openings were present in blood vessels with a diameter of 7 to 8 micra or more. These gaps were 0.1 to 0.8 micra in width; portions of intercellular junctions were often present in one or both of the margins. The underlying basement membrane was morphologically intact. An accumulation of tracer particles and chylomicra against the basement membrane indicated that the latter behaved as a filter, allowing fluid to escape but retaining and concentrating suspended particulate matter of the size used. Uptake of tracer particles by endothelial vesicles was minimal. Phagocytosis by endothelial cells became more prominent at 3 hours, but as a secondary occurrence; the pericytes were actively phagocytic at all stages. At the 3-hour stage no leaks were found. The changes induced by histamine and serotonin were indistinguishable, except that the latter was more potent on a mole-to-mole basis. In control animals only small accumulations of tracer particles were found in the wall of a number of blood vessels. With regard to the pathogenesis of the endothelial leaks, the electron microscopic findings suggested that the endothelial cells become partially disconnected along the intercellular junctions. Supporting evidence was provided at the level of the light microscope, by demonstrating—in the same preparation—the leaks with appropriate tracer particles1, and the intercellular junctions by the silver nitrate method. The lipid nature of the chylomicron deposits observed in electron micrographs was also confirmed at the level of the light microscope, using cremasters fixed in formalin and stained in toto with sudan red.

The passage of colloidal carbon through inflamed endothelium

1962 ◽  
Vol 156 (965) ◽  
pp. 550-552 ◽  
Keyword(s):  
Endothelial Cells ◽  
Basement Membrane ◽  
Electron Micrographs ◽  
Intercellular Junctions ◽  
Colloidal Carbon ◽  
Inflamed Endothelium

Colloidal carbon, injected intravenously, accumulates in the walls of the venules in the inflamed mesentery of the rat. Electron micrographs demonstrate that the carbon passes through open intercellular junctions of the endothelium. Carbon is found to be contained within the walls of venules by the basement membrane of the endothelium and also by the periendothelial sheath of cells and their basement membrane. Little carbon has been found within the cytoplasm of inflamed endothelial cells.

scholarly journals ELECTRON MICROSCOPE STUDIES ON THE DICTYOSOMES AND ACROBLASTS IN THE MALE GERM CELLS OF THE CRICKET

1956 ◽  
Vol 2 (4) ◽  
pp. 123-128 ◽  
Author(s):  
H. W. Beams ◽  
T. N. Tahmisian ◽  
R. L. Devine ◽  
Everett Anderson
Keyword(s):  
Electron Microscope ◽  
Golgi Apparatus ◽  
Electron Micrographs ◽  
Germ Cells ◽  
Light Microscope ◽  
Golgi Body ◽  
Duplex Structure ◽  
Male Germ Cells ◽  
Secondary Spermatocyte ◽  
A Chain

The dictyosome (Golgi body) in the secondary spermatocyte of the cricket appears in electron micrographs as a duplex structure composed of (a) a group of parallel double-membraned lamellae and (b) a group of associated vacuoles arranged along the compact lamellae in a chain-like fashion. This arrangement of ultramicroscopic structure for the dictyosomes is strikingly comparable to that described for the Golgi apparatus of vertebrates. Accordingly, the two are considered homologous structures. Associated with the duplex structure of the dictyosomes is a differentiated region composed of small vacuoles. This is thought to represent the pro-acrosome region described in light microscope preparations. In the spermatid the dictyosomes fuse, giving rise to the acroblast. Like the dictyosomes, the acroblasts are made up of double-membraned lamellae and associated vacuoles. In addition, a differentiated acrosome region is present which, in some preparations, may display the acrosome vacuole and granule. Both the dictyosomes and acroblasts are distinct from mitochondria.

The Ultra-fine Structure of Lipid Globules in the Neurones of Helix aspersa

1958 ◽  
Vol s3-99 (46) ◽  
pp. 279-284
Author(s):  
J.T. Y. CHOU ◽  
G. A. MEEK
Keyword(s):  
Methylene Blue ◽  
Fine Structure ◽  
Electron Microscope ◽  
Electron Micrographs ◽  
Light Microscope ◽  
Helix Aspersa

The three kinds of lipid globules recognizable in the living neurones of Helix aspersa have been examined under the electron microscope. The globules of the kind that can be stained blue with methylene blue during life are seen in electron micrographs as spheres or spheroids, with concentric lamination, after calcium-osmium fixation. After fixation with sucrose-osmium laminated crescentic bodies are seen instead; these appear to be formed by distortion of the ‘blue’ globules. The yellow globules contain electrondense material, and sometimes appear reticular. It is possible that the yellow globules may originate by transformation of some of the ‘blue’ globules. The colourless globules generally appear as crenated objects; this appearance may be a shrinkage artifact. Apart from the mitochondria and the three kinds of lipid globules described, no other object large enough to be identified with the light microscope has been seen in the cytoplasm.

scholarly journals An Electron Microscope Study of the Source and Distribution of Ferritin in Hepatic Parenchymal Cells of the Newborn Rabbit

Blood ◽  
1960 ◽  
Vol 15 (4) ◽  
pp. 480-490 ◽  
Author(s):  
JAMES C. HAMPTON
Keyword(s):  
Electron Microscope ◽  
Microscope Study ◽  
Light Microscope ◽  
Electron Microscope Study ◽  
Hepatic Cell ◽  
Cell Cytoplasm ◽  
Electron Microscopic ◽  
Newborn Rabbit ◽  
Blue Reaction ◽  
Parenchymal Cells

Abstract Evidence that erythrocytes are phagocytized and dismantled by hepatic parenchymal cells in the newborn rabbit is presented. It is concluded that in these cells iron is recovered from disintegrating erythrocytes, synthesized into ferritin and released into the hepatic cell cytoplasm and into the biliary passages. These conclusions are based upon observations on the distribution of material giving the Prussian blue reaction in sections of liver as revealed by the light microscope and upon electron microscopic images of particles displaying the size, density and configuration of the ferritin molecule.

scholarly journals Human iPSC-derived mesodermal progenitor cells preserve their vasculogenesis potential after extrusion and form hierarchically organized blood vessels

2021 ◽  
Author(s):  
Leyla Dogan ◽  
Ruben Scheuring ◽  
Nicole Wagner ◽  
Yuichiro Ueda ◽  
Philipp Woersdoerfer ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Blood Vessels ◽  
Progenitor Cells ◽  
Vessel Wall ◽  
De Novo ◽  
Hierarchical Organization ◽  
Wall Structure ◽  
Electron Microscopic ◽  
Vessel Formation

Post-fabrication formation of a proper vasculature remains an unresolved challenge in bioprinting. Established strategies focus on the supply of the fabricated structure with nutrients and oxygen and either rely on the mere formation of a channel system using fugitive inks, or additionally use mature endothelial cells and/or peri-endothelial cells such as smooth muscle cells for the formation of blood vessels in vitro. Functional vessels, however, exhibit a hierarchical organization and multilayered wall structure that is important for their function. Human induced pluripotent stem cell-derived mesodermal progenitor cells (hiMPCs) have been shown to possess the capacity to form blood vessels in vitro, but have so far not been assessed for their applicability in bioprinting processes. Here, we demonstrate that hiMPCs, after formulation into an alginate/collagen type 1 bioink and subsequent extrusion, retain their ability to give rise to the formation of complex vessels that display a hierarchical network in a process that mimicks the embryonic steps of vessel formation by vasculogenesis. Histological evaluations at different time points of extrusion revealed initial formation of spheres, followed by lumen formation and further structural maturation as evidenced by building a multilayered vessel wall and a vascular network. These findings are supported by immunostainings for endothelial and peri-endothelial cell markers as well as electron microscopic analyses at the ultrastructural level. Moreover, capillary-like vessel structures deposited a basement membrane-like matrix structure at the basal side between the vessel wall and the alginate-collagen matrix. These results evidence the applicability and great potential of hiMPCs for the bioprinting of vascular structures mimicking the basic morphogenetic steps of de novo vessel formation during embryogenesis.

scholarly journals Casting Cells

2001 ◽  
Vol 9 (3) ◽  
pp. 3-5
Author(s):  
Stephen W. Carmichael
Keyword(s):  
Endothelial Cells ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Silver Nitrate ◽  
Blood Vessels ◽  
Nerve Fiber ◽  
Corrosion Casts ◽  
New Information ◽  
Scanning Electron

It's always refreshing to read about two old techniques being combined in a novel way to yield new information. Osamu Ohtani and Yuko Ohtani recently accomplished this. Louis Ranvier probably introduced the use of silver nitrate as a histology stain over a century ago. Whereas Ranvier is best known for describing nodes along the nerve fiber, he also demonstrated that silver nitrate stained endothelial cells, allowing their borders to be clearly visualized. In the 1970's, Takuro Murakami first used the scanning electron microscope (SEM) to examine corrosion casts of the vasculature. Much of what we currently know about the microarchitecture of blood vessels has been discovered using this technique.

scholarly journals Rabbit Heart Valve Basement Membrane: Low Platelet Reactivity

Blood ◽  
1973 ◽  
Vol 41 (3) ◽  
pp. 359-367 ◽  
Author(s):  
Arcot D. Suresh ◽  
Michael B. Stemerman ◽  
Theodore H. Spaet
Keyword(s):  
Endothelial Cells ◽  
Basement Membrane ◽  
Heart Valves ◽  
Platelet Adhesion ◽  
Platelet Reactivity ◽  
Platelet Rich Plasma ◽  
Rabbit Heart ◽  
Electron Microscopic ◽  
Mechanical Methods ◽  
Microscopic Studies

Abstract Electron microscopic studies were performed on rabbit heart valves, and all four valves were found to be lined with a continuous basement membrane (BM). The valvular BM was liable to digestion by either trypsin or collagenase, but brief exposure to trypsin was suitable for desquamating endothelial cells, while leaving BM exposed and intact. Such preparations were used to determine their platelet reactivity with heparinized and citrated whole blood or with platelet-rich plasma. Although various conditions of exposure were used, including shaking and centrifugation, little or no platelet adhesion to the BM was observed. With similar conditions of exposure, preparations of collagen showed massive platelet adhesion accompanied by aggregation. This vascular BM was similarly nonreactive to platelets when endothelial cell removal was accomplished by mechanical methods. Rabbit valvular BM appears to be a poorly thrombogenic surface.

Bridging the Resolution Gap: Correlated 3D Light and Electron Microscopic Analysis of Large Biological Structures

1999 ◽  
Vol 5 (S2) ◽  
pp. 526-527
Author(s):  
Maryann E. Martone
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Surface Area ◽  
Light Microscope ◽  
Microscopic Analysis ◽  
Electron Microscopic Analysis ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Biological Structures ◽  
Ganglion Neurons

One class of biological structures that has always presented special difficulties to scientists interested in quantitative analysis is comprised of extended structures that possess fine structural features. Examples of these structures include neuronal spiny dendrites and organelles such as the Golgi apparatus and endoplasmic reticulum. Such structures may extend 10's or even 100's of microns, a size range best visualized with the light microscope, yet possess fine structural detail on the order of nanometers that require the electron microscope to resolve. Quantitative information, such as surface area, volume and the micro-distribution of cellular constituents, is often required for the development of accurate structural models of cells and organelle systems and for assessing and characterizing changes due to experimental manipulation. Performing estimates of such quantities from light microscopic data can result in gross inaccuracies because the contribution to total morphometries of delicate features such as membrane undulations and excrescences can be quite significant. For example, in a recent study by Shoop et al, electron microscopic analysis of cultured chick ciliary ganglion neurons showed that spiny projections from the plasmalemma that were not well resolved in the light microscope effectively doubled the surface area of these neurons.While the resolution provided by the electron microscope has yet to be matched or replaced by light microscopic methods, one drawback of electron microscopic analysis has always been the relatively small sample size and limited 3D information that can be obtained from samples prepared for conventional transmission electron microscopy. Reconstruction from serial electron micrographs has provided one way to circumvent this latter problem, but remains one of the most technically demanding skills in electron microscopy. Another approach to 3D electron microscopic imaging is high voltage electron microscopy (HVEM). The greater accelerating voltages of HVEM's allows for the use of much thicker specimens than conventional transmission electron microscopes.

scholarly journals THE GLOMERULUS IN EXPERIMENTAL RENAL DISEASE IN RATS AS OBSERVED BY LIGHT AND ELECTRON MICROSCOPY

1955 ◽  
Vol 102 (5) ◽  
pp. 573-580 ◽  
Author(s):  
Carolyn F. Piel ◽  
Luther Dong ◽  
F.W.S. Modern ◽  
Joseph R. Goodman ◽  
Roger Moore
Keyword(s):  
Electron Microscopy ◽  
Endothelial Cells ◽  
Basement Membrane ◽  
Light Microscopy ◽  
Light And Electron Microscopy ◽  
Electron Microscopic ◽  
Crescent Formation ◽  
Colloidal Iron ◽  
Narrow Channels ◽  
Glomerular Capillary

Nephrotoxic serum disease in rats has been studied by light and electron microscopy from 1 hour to 10 weeks after production of the disease. By light microscopy leucocytic infiltration of the glomerular capillary was observed between the 3rd and 6th hour. At 6 hours an increase in colloidal iron-positive material was observed coating the extraluminal surface of the capillaries. Also at this time swelling of the endothelial cells becomes prominent. By 72 hours, thickening of the basement membrane was observed. Glomerular capillary thrombi were observed in approximately half the tissue examined in the first 2 weeks of disease. 50 per cent of the animals showed severe chronic lesions, exudation into the capsular space, crescent formation, and obliteration of glomeruli. At 1 hour electron microscopic pictures showed that osmophilic material may line the foot processes of the epithelial cells and obliterate all but narrow channels of the space between the feet. By 6 hours thickening of the basement membrane was prominent. This change persisted throughout 10 weeks of observation. The tissue from animals which had severe chronic alterations by light microscopy revealed changes which could not be interpreted at this time.

scholarly journals Structure of the Rete Mirabile in the Kidney of the Rat as Seen with the Electron Microscope

1960 ◽  
Vol 7 (1) ◽  
pp. 103-106 ◽  
Author(s):  
J. B. Longley ◽  
W. G. Banfield ◽  
D. C. Brindley
Keyword(s):  
Endothelial Cells ◽  
Fine Structure ◽  
Electron Microscope ◽  
Electron Micrographs ◽  
Simple Diffusion ◽  
Functional Capabilities ◽  
Rete Mirabile ◽  
Peritubular Capillaries ◽  
Fenestrated Endothelium

Electron micrographs of the rete mirabile in the medulla of the rat have revealed that the endothelium of the afferent and efferent vessels are markedly different in fine structure. The venous capillaries returning blood from the papilla are lined with a fenestrated endothelium much like that in the peritubular capillaries of the kidney. The arterial capillaries delivering blood to the papilla have an unperforated lining of overlapping endothelial cells with extremely irregular tapered margins. It is pointed out that the organization of particularly the latter vessels suggests that the functional capabilities of these retia go beyond those of a simple diffusion countercurrent exchanger.

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