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At least 703 records · Page 39Linked to original sources
PubMed1984

Some scanning electron microscopic studies of the surface of coronal sections cut from the rat brain.

The cut surfaces of coronal sections of the rat cerebral hemispheres have been examined with the scanning electron microscope. Under low magnification the structures of the brain are easily identified. Using the focusing power of the microscope and the ability to tilt the specimen in its column, under higher magnification the neurones, glial cells, cell processes, bundles of myelinated axons and the cerebral blood vessels can be examined in great detail. This method of study should prove of value in the future for the investigation of brains which have been subjected to experimental procedures and those affected by disease.

Animals↗
PubMed1981

Leukocytes in the glomerular capillary lumen in Masugi nephritis. A scanning electron microscopic study of freeze-cracked specimens.

Masugi nephritis was induced in rats by a single intravenous injection of rabbit anti-rat kidney serum, and studied with a scanning electron microscope. A characteristic finding was the presence of white cells, probably polymorphonuclear leukocytes, with many microspikes which penetrated through degenerated glomerular endothelial cells to be in direct contact with the glomerular basement membrane. This finding confirms the pathogenic role of leukocytes in glomerulonephritis induced by anti-glomerular basement membrane antibody.

Animals↗
PubMed2005

Nanomanipulator-assisted fabrication and characterization of carbon nanotubes inside scanning electron microscope.

We have installed two nanomanipulators, which can travel about 20mm with a minimum increment of 1 nm, for manipulation of nanostructured materials inside field-emission scanning electron microscope (FE-SEM). Both manipulators render motions in x, y, and z directions, providing various manipulation freedoms such as moving, bending, cutting, and biasing. In addition, we have conducted in situ characterization of the electrical breakdown of multi-walled carbon nanotubes (MWCNTs). Our results demonstrate the possibility that MWCNTs can be used as a gas sensor.

Journal Article↗
PubMed1989

Supraependymal cells and fibers in the third ventricle of the domestic chicken. A scanning electron microscopic study.

Supraependymal cells, fibers and what are presumed to be neuronal bulb-like projections were found in the third ventricle of the domestic chicken with a scanning electron microscope. At least two types of supraependymal cells were found: neuron-like cells and phagocyte-like cells. The former were predominantly seen in the area of the paraventricular organ and infundibular recess. The latter were abundant on the ventricular surface of the median eminence and subfornical organ. Bulb or club-like projections thought to be the dendritic terminals of CSF-contacting neurons were observed in the area of the paraventricular organ and infundibular recess. Similar structures were observed at the preoptic recess as well. The supraependymal neuronal components found in the domestic chicken differed from those of mammals in several respects: 1. the wall of the third ventricle was devoid of supraependymal fibrous plexus except for that of the paraventricular organ; 2. bulb-like projections were abundant in the area of the paraventricular organ; 3. supraependymal neuron-like cells were unipolar or bipolar in appearance. These data underline the dissimilarity of the CSF-contacting neuronal system of birds and mammals.

Animals↗
PubMed1989

Histologic and scanning electron microscopic observations of intrahepatic peribiliary glands in normal human livers.

The three-dimensional configuration of the intrahepatic peribiliary glandular system was examined in normal autopsied livers by scanning electron microscopic observations of the intrahepatic biliary tract casts. Biliary tract casts were made by injection of resin into the biliary tree and subsequent corrosion of the hepatic parenchyma. There were many projections on the surface of the biliary casts and they could be morphologically classified into pouchlike and treelike projections. These projections tended to be arranged on opposite sides of the biliary casts. The treelike projections from the large bile ducts at the bifurcation frequently anastomosed each other. By comparing the findings of biliary casts with histologic findings as well as the measuring of these projections and thickness of bile duct wall, it was suggested that the treelike projections correspond to the extramural peribiliary glands and the pouchlike ones to the intramural ones, both of which are normally present around the intrahepatic biliary tree. Thus, it was suggested stereologically in this study that substance(s) produced in the intrahepatic peribiliary glands may be secreted into the bile ductal lumen and thereby participate in the modification of bile composition.

Bile Ducts, Intrahepatic↗
PubMed1981

Somitogenesis in the amphibian Xenopus laevis: scanning electron microscopic analysis of intrasomitic cellular arrangements during somite rotation.

The intrasomitic changes in cell arrangement which accompany somite rotation during somitogenesis in Xenopus laevis were analysed with the scanning electron microscope (SEM). Longitudinal, horizontal fractures of whole embryos were examined at various dorsoventral levels of stage-22 to -24 embryos. Observations of the gross morphological features of somitogenesis, and the cellular changes which accompany somite segmentation and somite rotation were made. Several of these observations lead to modifications of previous models for the cellular basis of somitogenesis in Xenopus. Individual cellular rearrangements, rather than simultaneous block rotation of a whole somite, appear to be responsible for the 90 degrees rotation of myotomal cells within a single somite. Cellular arrangements in fused somites were also examined. Some ultraviolet-irradiated embryos displayed a complete lack of a notochord. The somites in those embryos were fused across the midline beneath the neural tube. The dorsal and ventral arms of the somites are not fused. Normal rotation occurs only in the dorsal and ventral arms while, in the majority of cases, cells in the fused region fail to rotate normally. In some cases, individual cells in the fused region undergo partial rearrangement. Those observations support the notion that individual cellular rearrangements account for the rotation of the whole somite.

Animals↗
PubMed1992

[A scanning electron microscopic study of surface layer changes in artificial carious enamel].

The present study was carried out to describe surface changes and development of pathways of caries in vitro by the scanning electron microscope. Results indicate that direct crystal dissolutions of the surface layer itself are prominent features and recrystallization phenomenon is present in different degrees. The dissolution was more severe in Tome's process pit, focal hole and opening of striae of Retzius, but less severe in inter-rod areas.

Dental Caries↗
PubMed1992

Scanning electron microscopic study on the lingual papillae in the Manchurian chipmunk, Tamias sibiricus asiaticus.

The superfacial structures of the tongues in the Manchurian Chipmunk, Tamias sibiricus asiaticus, were observed by scanning electron microscope. The tongues were long, tapering, narrow and thick with a long apical free portion and a small lingual prominence in the posterior half. In this animal, three circumvallate papillae were present in an inverted triangle, a minority of conical papillae on the pharyngeal part and parallel large conical papillae on the lateral border. The fungiform papillae were scanty on the dorsal surface. These characters suggested this animal was more primitive than the others in rodents.

Animals↗
PubMed1985

Blood vascular bed of the rat pituitary intermediate lobe, with special reference to its development and portal drainage into the anterior lobe. A scanning electron microscope study of vascular casts.

Blood vascular beds of the rat pituitary intermediate lobes were reproduced by injection of low viscosity methacrylate media, and then observed with a scanning electron microscope. Although the intermediate lobes of newborn and pubescent rat were poorly vascularized, the adult rat intermediate lobe contained numerous capillaries forming a fairly independent network whose density, however, was not so great as in the anterior and posterior lobes. The vascular network of the intermediate lobe could be divided into two parts: a superficial plexus close to the anterior lobe, and a deep one close to the posterior lobe, though the two plexuses were continuous with each other. The superficial plexus consisted of anastomosing capillaries, and the deep one of non-anastomosing capillaries with a palisade-fashioned arrangement. The superficial plexus seemed crucially important for the blood supply of the intermediate lobe since it developed or thickened as the animals aged. The superficial plexus received its proper afferent vessels from the middle and posterior hypophyseal arteries and emitted its proper efferent vessels continuous with the sinusoidal capillaries of the anterior lobe. The capillaries of the deep plexus usually communicated with the arterial capillaries of the posterior lobe and possibly represented another afferent route to the superficial plexus. This paper, thus, strongly suggests a portal circulation from the intermediate lobe to the anterior lobe though its functional significance is unknown.

Aging↗
PubMed2005

Scanning electron microscopic study on the microarchitecture of the vascular system in the pigeon lung.

The resin casts of the respiratory and vascular systems in pigeon lung were examined using a scanning electron microscope. The primary bronchi branched to form many secondary bronchi that anastomosed with each other via the parabronchi. Numerous infundibula protruded from the parabronchi via the atria and ramified into the air capillaries. The pulmonary artery entered into the lung and branched into three vessels that coursed the interparabronchial parts. The intraparabronchial arterioles penetrated the gas-exchange tissue to form the anastomosing networks of blood capillaries. The observation of the double casts of the respiratory and vascular systems revealed three-dimensional complicated networks of air capillaries and blood capillaries.

Animals↗
PubMed1993

A scanning electron microscopic study on three-dimensional organization of human diaphragmatic lymphatics.

Three-dimensional organization of diaphragmatic lymphatics in five fetuses was studied by the lymphatic casts of scanning electron microscope. A new resin consisting of piperylene, acrylic ester and styrene was used instead of Mercox. The diaphragmatic lymphatics formed rich networks in the muscular portion. There were two layers of lymphatic networks, i.e. the submesothelial network and the deeper network and only one layer in the tendinous portion of the diaphragm. The lymphatic networks were more dense in the tendinous portion than these in the muscular portion. The lymphatics were mainly composed of main lymphatic vessels and anastomosing side branches. The side branches often communicated the submesothelial network with the deeper network in the muscular portion. The main lymphatics were connected at regular intervals by way of transverse side branches in the tendinous portion. Numerous constrictions and notches showing the presence of lymphatic valves were often found on the cast surface of the main lymphatic vessels and the side branches. The lymphatics extended as far as the terminal branches, i.e. the lymphatic lacunae recognized as broad, flattened and blind-ended. In the present study, three-dimensional organization of human diaphragmatic lymphatics was for the first time described. It was suggested that the passageway of the lymph flow out of the peritoneal cavity may be explained. From the peritoneal stomata, the lymph of the peritoneal cavity flowed into the channels under the peritoneum, then into the lymphatic lacunae and finally into the lymphatic networks under the diaphragmatic pleura.

Diaphragm↗
PubMed1983

Myofibrillogenesis in vitro as seen with the scanning electron microscope.

The present study describes an experimental approach whereby myofibrillogenesis and the three-dimensional arrangement of myofibrils present within cultured skeletal muscle cells can be examined using the scanning electron microscope. This procedure uses cells that have been cultured on gold-coated coverslips, and treated with Triton X-100 to extract the cell membrane and the soluble cytoplasm. Subsequent electroconductive staining by treatment with thiocarbohydrazide and osmium allows the myofibrils to be visualized. The images of myofibrils in various states of development observed by this method generally accords to those previously reported by transmission electron microscopy. Cell elongation and adhesion to the substrate causes mechanical stress from different directions which meet at branchings of the cultured myotubes. Many myofibrils are observed to run in the direction of the inferred stress lines.

Animals↗
PubMedDate not supplied

High-resolution field emission scanning electron microscope imaging of internal cell structures after Epon extraction from sections: a new approach to correlative ultrastructural and immunocytochemical studies.

The availability of high-resolution field emission scanning electron microscopes (FESEM) and the recent development of a less destructive method for extracting Epon from sections motivated us to investigate these techniques for the study of internal cell structures. We chose the nuclear pore complex (NPC) and insect striated muscle as test objects. Chemically fixed or rapidly cryoimmobilized samples were embedded in Epon 812. The Epon was extracted from 200- to 300-nm-thick sections with a modified potassium methoxide-crown ether complex. The samples were viewed with high-resolution FESEM at low voltages. In tangential sections of isolated nuclear envelopes from Xenopus oocytes the cytoplasmic and intranuclear components ("fishtraps") of NPCs appeared identical to what has been described from whole mounts. In cross sections, fishtraps are seen in side view, which is possible only with this technique. In longitudinal and cross sections of insect flight muscle the classical arrangement of myofilaments and cross-bridges is well preserved. This method now makes it possible to image internal cell structures from any desired angle by high-resolution FESEM. Immunolabeling studies on the rabbit psoas muscle demonstrated that antigenicity of alpha-actinin was retained in Epon-extracted sections. Immunogold labeling with antibodies against alpha-actinin conjugated to 3-nm gold beads was intense, highly specific, and restricted to the Z lines. This method can overcome the penetration problem of immunogold labeling, since any cell component can be positioned at the surface of the section. Obviously this approach can become a powerful new tool for many areas of structural cell biology.

Actinin↗
PubMed1993

Environmental scanning electron microscope (ESEM) evaluation of crystal and plaque formation associated with biocorrosion.

The biofilm attributed to Desulfovibrio vulgaris growing in the presence of ferrous metals was examined with an environmental scanning electron microscope. This novel microscope produced images of iron sulfide colloids and other iron containing structures that had not been reported previously. A plaque composed of iron sulfide enveloped the surface of the corroding metal while crystals containing magnesium, iron, sulfur, and phosphorus were present in the culture where corrosion was in progress. A structure resembling the tubercule found in aerobic corrosion was observed on stainless steel undergoing biocorrosion and the elements present in this structure included sulfur, iron, chloride, calcium, potassium, and chromium.

Biodegradation, Environmental↗
PubMed2004

Three-dimensional topographic scanning electron microscope and Raman spectroscopic analyses of the irradiation effect on teeth by Nd:YAG, Er: YAG, and CO(2) lasers.

A three-dimensional analyzer installed in a scanning electron microscope was used to evaluate the morphology and surface roughness using noncontact profilometry. Observations were carried out on the enamel and dentin surface irradiated by three different lasers: Nd:YAG (wavelength 1.06 microm), Er:YAG (2.94 microm), and CO(2) (10.6 microm). Spectroscopic analysis was done by Raman spectroscopy for nonirradiated and laser-irradiated surfaces. The lasers were applied perpendicularly to vertically sectioned and polished human extracted caries-free molars. The tooth was sectioned at each cavity for cross-section analysis after laser irradiation. Irradiation by Nd:YAG and CO(2) lasers of the enamel surface showed an opaque white color, different from dentin where the surface turned black. The Er:YAG laser induced no changes in color of the dentin. Numerous cracks associated with thermal stress were observed in the CO(2) laser-irradiated dentin. Noncontact surface profile analysis of Er:YAG laser-irradiated enamel and dentin showed the deepest cavities, and direct cross-sectional observations of them showed similar cavity outlines. The CO(2) laser-irradiated dentin had the least surface roughness. Raman spectroscopic analysis showed that fluorescence from the laser-irradiated tooth was generally greater than from nonirradiated teeth. Bands in dentin attributed to organic collagen matrix were lost after Nd:YAG and CO(2) laser irradiation, and a broad peak due to amorphous carbon appeared. The Er:YAG laser-irradiated dentin showed no sign of a carbon band and had more suitable results for dental ablation. Noncontact surface profile analysis was effective to evaluate the structural change in the tooth in the microarea of study after laser irradiation.

Humans↗
PubMed1977

Transmission and scanning electron microscopic observations of mouse adrenocortical adenoma cells (Y-1) in non-stimulated and stimulated states.

ACTH sensitive murine adrenocortical adenoma cells (Y-1) were examined by transmission and scanning electron microscopes under non-stimulated and stimulated conditions. They showed the ultrastructural characteristics which were fairly different from those of the original adrenocortical cells of LAF1 mice. The smooth-surfaced endoplasmic reticulum (sER) were poorly developed, and the mitochondrial cristae showed lamellar rather than tubular or tubulo-vesicular type. Administration of ACTH induced rounding-up of the Y-1 cells with slight increase in sER, BUt no mitochondria with vesicular inner structure appeared. The effects of dbcAMP on the morphology of the Y-1 cells were similar to those of ACTH except that the rounding-up occurred more rapidly and uniformly.

Adenoma↗