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Results for “scanning electron microscope”

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PubMed1995

Scanning electron microscope observations on Corrigia vitta (Dujardin, 1845) Shtrom, 1940 (Trematoda: Dicrocoeliidae).

The surface topography of the digenetic trematode Corrigia vitta is described by scanning electron microscope. It revealed the presence of several small sensory papillae on the oral sucker, ventral sucker and along the ventral surface of the fluke, several tegumental projections (spines or tubercles) covering the whole tegument, which vary in shape and length in different areas of the body, and several small invaginations (tegumental pores) are present allover the surface. The eggs are operculated at one pole and possess a smooth surface.

Animals↗

PubMed1992

Scanning electron microscopic observations of the immunodefensive systems with special reference to the surface morphology of the non-lymphoid cells.

This paper reviews scanning electron microscopic observations of cellular elements forming various lymphoid organs. The reticular cells in the secondary lymphoid organs are stellate, smooth-surfaced forms extending slender processes to comprise a three-dimensional network. The reticular fibers are usually covered by reticular cell processes, though they are naked in certain regions. Other types of reticular cells are observed in certain places: the "retothelial" type in the lymphatic sinus of the lymph nodes, and the "follicular dendritic" type in the germinal center of various lymphoid organs. The thymic epithelial cells are divided into two main types: stellate cells which form a three-dimensional meshwork throughout the thymus parenchyma; and large vacuolated cells located in the medulla. A continuous single layer consisting of the processes of the stellate epithelial cells separates the parenchyma from the connective tissues of the capsule, septa and vessels. The M cells in the epithelium of the gut-associated lymphoid tissues (GALTs) are cells with numerous irregular microprojections on the luminal surface. They often attach microorganisms to the luminal surface, reflecting their functions of antigen transport into the underlying lymphoid tissue. Lymphocytes of various shapes often cluster in the intercellular spaces under the M cells, a phenomenon believed to indicate direct stimulation of lymphocytes by certain transported substances. Macrophages are amoeboid cells independent of and unable to transform into reticular and endothelial cells, at variance with prerequisites of the reticulo-endothelial system concept. Multiple features of macrophages probably reflect the presence of the subpopulations as well as the phases of their activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1986

Blood vascular organization of the rat carotid body: a scanning electron microscopic study of corrosion casts.

The blood vascular bed of the rat carotid body was reproduced with methacrylate and observed under the scanning electron microscope. The carotid body received the proper carotid body artery from the common carotid body artery, which arose from the external carotid or occipital artery and gave off subsidiary branches to the tissues near the carotid body. The proper carotid body artery divided in the carotid body, ultimately breaking up into thick (main) or thin (subsidiary) arterial terminals to form the vascular plexus of the carotid body. This plexus contained both thick and thin capillaries. The thick capillaries arose from the thick and thin arterial terminals and formed the basic capillary network of the carotid body. The thin capillaries were only subsidiary, intercalated among the thick capillaries. A few accessory twigs of the proper carotid body artery passed through the carotid body and supplied the adipose and other tissues around the carotid body. Many venules arose from the thick capillaries of the carotid body and were collected into rostral and caudal efferent veins. These efferent veins received the veins from the tissues adjacent to the carotid body, and drained into the internal jugular vein. No arterio-venous anastomosis was found in, on or around the carotid body. The common carotid body artery and its subsidiary branches showed, at their origins, marked constrictions indicative of the arterial cushions, though the proper carotid body artery and its accessory twigs were not provided with such clear constrictions. These findings suggest that the inflow of blood into the common carotid body artery may be regulated by its constriction, especially of its arterial cushion, and that the subsidiary branches of the common carotid body artery and the accessory twigs of the proper carotid body artery may act as bypass-routes to eliminate the excessive inflow of blood into the carotid body. It is considered that the thin arterial terminals and thin capillaries may act as buffer channels to homogenize the blood flow within the carotid body.

Animals↗

PubMed1984

Three-dimensional architecture of altered dermal elastic fibers in pseudoxanthoma elasticum: scanning electron microscopic studies.

The three-dimensional architecture of the altered dermal elastic fibers of patients with pseudoxanthoma elasticum has been demonstrated using a scanning electron microscope. Each of the altered elastic fibers could be divided into three parts: (i) a normal-looking, slender part which is composed of thinner fibrils, (ii) a thickened, tortuous part covered with an amorphous substance, and (iii) a markedly damaged part where calcium is exposed to the surface of the fibers. The presence of calcium and phosphorus in the altered elastic fibers has been proved by an electron x-ray microanalysis.

Calcium↗

PubMedDate not supplied

[Surface of the olfactory region in man observed by scanning electron microscope].

This report describes the surface of the regio olfactoria of a 25-year-old man as observed in the scanning electron-microscope. Corresponding to the distal ends of the receptor cells, the surface displays various planes: (a) Upper-most is a film of mucus of varying thickness. (b) The olfactory hairs, which are arranged closely together, mostly in a parallel fashion in layers, dip into this mucus film. The long, distal parts of the olfactory hairs are of a rather uniform shape and form, together with the mucus film, a single functional unit. (c) Now follows a layer consisting of the short parts of the olfactory hairs. They branch from the olfactory vesiculae, mostly in a stellar fashion (5-12 on one vesicula) and arch themselves, after a short course, into the mucus film. (d) There then follows the plane of the olfactory vesiculae, mostly bulbous, partly club- and pyramidal in shape. (e) After that comes the plane of the microvilli receptors, which have about 100 or more villi on one cell. (f) Right at the bottom is the apical surface of the supporting cells, different in size, showing microvilli in a regularly arranged pattern. Because of the various planes of the surface of the olfactory region and because of the close situation of the long, distal parts of the olfactory hairs and their rather uniform shape, one could assume, from observations in the scanning electron microscope, that the olfactory-active molecules react immediately with the functional unit of mucus film and long distal parts of the olfactory hairs, so that for the different sense of smell, a quite different structure of the olfactory-active molecules must be assumed as a different shape of the distal ends of the olfactory receptors.

Adult↗

PubMed1989

[Scanning electron microscopic observation of the nasal mucosa microvasculature].

The normal microvasculature of a rat nasal mucosa was investigated in microcorrosion casts viewed under a scanning electron microscope. The nasal mucosa microvasculature was composed of arterioles, venules, capillaries and cavernous sinuses. Both arterioles and venules ran parallel to the long axis of the nasal concha. The capillaries and cavernous sinuses were particularly abundant and interconnected by means of numerous short anastomoses to form a rich dense network. A characteristic feature of the nasal mucosa vasculature was that the capillaries possessed a fenestrated structure, the venules and arterioles were porous, and the surface of cavernous sinuses formed a three dimensional lace-work structure.

Animals↗

PubMed2003

First tests of a dipole lens for a scanning electron microscope.

We have previously shown that a dipole lens has superior properties that are particularly suited for use in a low voltage scanning electron microscope (SEM) (Tsai & Crewe, 1996). The aberrations are lower than for any other type of lens and lead to a prediction of high resolution. We describe the construction details of a microscope based on this principle and present some early results.

Journal Article↗

PubMed1981

The effect of a cartilage bone marrow extract on experimentally induced osteoarthrosis in the knee joints of rabbits. A scanning electron microscopic study.

The development of osteoarthrosis following a partial meniscectomy on the knee cartilage of rabbits (Chinchilla hybrids) was monitored with a scanning electron microscope. Simultaneously, a study was made of the effect of the cartilage bone marrow extract Rumalon trademark on the development of the osteoarthrotic changes. Twelve days after the operation, osteoarthrotic changes were evident in the untreated operated joints. After 36 days the damage caused to the cartilage was already radical. The immobility of the operated joint also gave rise to obvious changes in the cartilage of the knee joints which had not undergone an operation. The irregular weight distribution due to the fixation of one joint was apparently enough to provoke degenerative processes on the other side. When the cartilage bone marrow extract Rumalon trademark was administered three times weekly (0.5 mg/kg body weight i.m.) a distinct retardation of the osteoarthrotic development in the early stages was observed. Where the changes had penetrated to the inner cartilage layers, no difference could be established compared to the untreated animals.

Animals↗

PubMed1990

Ultrastructural study of hip joint osteoarthritis. Scanning electron microscopic study of articular cartilage of femoral head.

The surface structure of four different articular cartilages of the femoral head was studied with scanning electron microscope in 12 cases of hip joint osteoarthritis. These articular cartilages were mink white, yellow, dusky red and hyperplastic and thickened. The osteoarthritic articular cartilage surface was uneven with puckerings of various height, width and orientation. The puckerings were covered with fibril network. The fibrils were exposed collagen fibrils and of different diameters. Wider fiber bundles without orientation were found on the fibril network. On the surface of the hyperplastic articular cartilage observed were many deep and oval spaces left behind after breakdown of the lacunae of cells in the clusters of articular chondrocytes. In the spaces, remnants of articular chondrocytes were seen.

Cartilage, Articular↗

PubMed1979

A preliminary scanning electron microscope examination of wear striation direction on primate teeth.

Wear striations experimentally produced on initially unworn teeth were examined at high magnification using a scanning electron microscope. Certain characteristics of individual wear striations on these teeth indicate the direction of motion that produced them. Other striations on worn teeth of American Indians and the Paleocene primate Phenocolemur show similar characteristics and correspond to mandibular movement during mastication.

Animals↗

PubMed2006

Charge contrast imaging of biomaterials in a variable pressure scanning electron microscope.

Charge contrast imaging (CCI) is a dynamic phenomenon recently reported in insulating and semiconducting materials imaged with low vacuum or variable pressure scanning electron microscopes (SEM). Data presented in this paper illustrates that CCI can also be applied to biominerals and biological soft-tissues and that useful and unique structural information can be obtained from routine samples. Various resin-embedded samples were considered and example images from several different biomaterials are presented. Due to the diverse nature of samples that appear to exhibit charge contrast, this imaging technique has prospective application in a wide range of biological and biomedical research. This work represents the first application of CCI to biomaterials and in particular, highlights a new method for investigating the formation, structure and growth of biominerals.

Animals↗

PubMed1984

Improved coating and fixation methods for scanning electron microscope autoradiography.

A simple apparatus for emulsion coating is described. The apparatus is inexpensive and easily assembled in a standard glass shop. Emulsion coating for scanning electron microscope autoradiography with this apparatus consistently yields uniform layers. When used in conjunction with newly described fixation methods, this new approach produces reliable autoradiographs of undamaged specimens.

Arginine↗

PubMed1985

Behaviour of Sarcoptes scabiei in its burrow in hyperkeratotic scabies. A scanning electron microscopic study.

The behaviour of Sarcoptes scabiei var. hominis has been studied in the skin of 2 patients with hyperkeratotic scabies. After examination under the scanning electron microscope, the skin specimens can be reprocessed for light microscopic examination. Original aspects and the dynamics of the burrowing parasite are presented, namely its penetration into the epidermis, the elimination of digestive residues and the maturation of the parasite's eggs.

Adult↗

PubMed1984

[Oral epithelium during tooth eruption in the rat: a scanning electron microscopic study].

The evolution of the ultrastructural aspect of the oral epithelium during the pre- and posteruptive periods of rat molars was investigated using a scanning electron microscope. The eruption is preceded by a rupture of the superficial layers of the oral epithelium with a desquamation following concentrical circles. As the tooth erupts, the epithelial attachment is generated from ameloblasts.

Aging↗

PubMed1993

The behaviour of tympanic membrane perforations in tissue culture: a scanning electron microscopic study.

The effects of keeping rat tympanic membranes with an artificially made pars tensa perforation in tissue culture were observed under a scanning electron microscope. After one day and onwards, spreading and thickening of the keratinizing, outer squamous epithelium (OE) was noted. In addition, ballooning of the innermost cells of the outer epithelium apposing the inner tympanic epithelium (IE) was seen. No appreciable reaction was noted in the connective tissue layer of the drum. The inner tympanic epithelium appeared to be swollen, containing spherical structures in the cytoplasm, especially close to the area of contact with the outer meatal epithelium. No complete cover of the drum defect was seen after 14 days of tissue culture. Hyperplasia and spreading of the keratinizing, outer squamous epithelium of the drum is not sufficient to achieve covering of a drum perforation and complete healing cannot take place unless supported by granulation tissue formation.

Animals↗

PubMed1978

Transmission and scanning electron microscope preparations of the same cell culture.

A technique has been developed which allows transmission electron microscopy and scanning electron microscopy to be performed on the same cell culture sample. The technique uses the Costar 3,393 Leighton Tube containing a plastic insert, which does not stick to epoxy, for transmission electron microscopy. A cut piece of the plastic insert can be critical point dried, sputter coated and viewed under high vacuum with the scanning electron microscope.

Cells, Cultured↗

PubMed1978

A scanning electron microscope study of cell shape and cell appendages in the primitive streak region of the rat and chick embryo.

This report provides a scanning electron microscopic account of cell shapes and cell appendages that are observed in the primitive streak region of the rat and chick embryos. Epiblast cells become progressively elongated in the primitive streak region until flask cells predominate medially. The flask cells have a broad basal end directed toward the endoderm. In addition to fine filopodia, broad lamellipodia are found anchoring the flask cells to subjacent cells. The primary mesenchyme cells are at first round in shape and closely packed, but laterally are flattened and more dispersed. The mesenchyme cells are associated with each other by filopodia and lamellipodia and with the epiblast and endoderm by filopodia. On the basis of this description it is suggested that cell movement through the primitive streak occurs by cell extension, attachment by basal lamellipodia, and cell shortening that results in the movement of individual cells in a cell stream.

Animals↗

PubMed1975

Scanning electron microscopic observations of endothelial changes in experimentally induced atheromatosis of rabbit aortas.

Following the administration of cholesterol for a period of 6-7 weeks, Scanning Electron Microscopic (S.E.M.) observations revealed mono-cellular, crater-like and dome-shaped endothelial changes on top of the large intimal plaques in the rabbit aortas. Finger-like and other shaped cell protrusions were observed at the edges of these crater-like and dome-shaped endothelial changes, giving the intimal plaques a rough appearance. At other sites, normal, smooth, although irregularly arranged, endothelial cells covered the lesions. By impregnating the cell borders with silver-nitrate or silver proteinate containing perfusates, it was possible in most cases to ascertain that the lesions were derived from changes in one cell or from changes in a small collection of cells. S.E.M.-observations further revealed crater-like and dome-shaped endothelial changes to be present in large fields or as isolated cell changes in normal areas at sites where no gross lesions were observed with the light microscope. In addition large, multi-cellular, crate-like endothelial changes were observed at the edges of the large intimal plaques. At these sites several endothelial cells were lacking, leaving behind a crater in which sometimes cells and a few fibrin threads were found. Following the administration of cholesterol for periods of 4-5 and 2-3 weeks similar monocellular changes were observed, some extending over large areas, other as single cells in apparently normal surroundings. Quantitatively the number of lesions was less than when the cholesterol was administered for a longer period. Transmission electron microscopic studies revealed the presence of large amounts of membrane-bound lipid globules in the subendothelial spaces and within some endothelial cells, structures which were assumed to be cross-sections of the crater-like or dome-shaped endothelial cell protrusions, visible with the S.E.M.

Animals↗