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Results for “scanning electron microscope”

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At least 631 records · Page 35Linked to original sources

PubMed1989

Scanning electron microscopic investigation of maxillary lateral incisors with a radicular lingual groove.

Fourteen human lateral incisors with a radicular lingual groove were observed under the scanning electron microscope to explore the communications between the groove and the pulp cavity. Observations showed that accessory foramina could be found not only in the groove, but also in the corresponding wall of the pulp cavity and a cross section. A complete lack of closure of the calcified tissues along the groove, allowing for direct connection of the pulp and the periodontium, was not found in these specimens. Therefore, it is suggested that accessory canals are the main way of communication between the pulp and the periodontium of the incisors with a radicular lingual groove. Because the accessory canals could be found either in the crown part or in the root part of the groove, infectious materials may get into the pulp cavity when there are pathologic conditions either through accessory foramina in the crown part or through accessory foramina exposed by localized periodontitis around the groove.

Dental Pulp Cavity↗

PubMed1985

Three-dimensional organization of lymphatics and their relationship to blood vessels in rabbit small intestine. A scanning electron microscopic study of corrosion casts.

Casts of small intestinal blood vessels and lymphatics in the rabbit were made with methacrylate and observed under a scanning electron microscope (SEM). In casting the lymphatics, a specially diluted low viscosity medium was injected intraparenchymally into the intestinal submucosa. This parenchymal injection allowed good reproduction of fine lymphatics, including the initial lacteals in the villi. The central lacteals were completely surrounded externally by the subepithelial blood capillary networks of the intestinal villi. Individual villi in the lower intestine contained only one central lacteal that drained through a thin lymphatic in the glandular layer into the submucosal lymphatic plexus. Villi in the upper small intestine were broader than those in the lower small intestine, and contained two to five lacteals. They anastomosed with each other at the villous base and formed a markedly expanded sinus. The cast submucosal lymphatics frequently showed constrictions strongly suggestive of valves. It was constantly observed that well-developed lymphatics in the submucosa ran in pairs and held an arteriole or artery between them. This close association of the lymphatics with arteries suggests that arterial vasomotion might provide an important hydrodynamic energy source for lymph formation and transport.

Animals↗

PubMed1981

An universal and accurate replica technique for scanning electron microscope study in clinical dentistry.

One of the main concerns of dental research is the observation of the oral tissues and the materials applied to the dentition. The changes in composition and structure of the outer surfaces and the materials deposited on these surfaces are of special interest. In the literature, a variety of replica techniques for these purposes is described (Grundy in 1971 [12]; Saxton in 1973 [25]). The use of these techniques is limited because of artifacts in the samples, and a restricted resolution power resulting from useful magnifications in the order of 800x. An accurate and universal replica technique for the examination of specimens to be viewed under the SEM has been developed. The first impression is made by a light body silicone elastomer (President Coltene). The positive replica is made by electrodeposition of copper in an electro plating bath (Acru plat 5 electronic, Dr. Th. Wieland, D-7530 Pforzheim). The reliability and accuracy of this replica technique was verified by a scanning electron microscopic comparison of the replicas and the actual structures of etched enamel. To illustrate the applicability of the replica technique to structures with much lower hardness, also high resolution images of dental plaque were produced. The copper surface offers a perfect, original and proper electroconductive medium that withstands the bombardment of electrons and the relatively severe conditions in the scanning electron microscope. Reproducibility was accurate as judged by the duplication in position, size, and shape of the fine detail at magnifications of 7500x offering a resolution of 25 nm.

Bacteria↗

PubMed2001

The morphology of the iridocorneal angle in the eye of buffaloes (Bos bubalis): a light and scanning electron microscopic study.

The morphology of the iridocorneal angle in the eye of the buffalo (Bos bubalis) was studied in eighteen eyes using light and scanning electron microscope (SEM). The buffalo iridocorneal angle included the pectinate ligament, the ciliary cleft, the trabecular meshwork (uveal and corneoscleral) and the angular aqueous plexus. The pectinate ligament was prominent anteriorly and appeared as strong, thick compact structure. The strands of the pectinate ligament were short and had narrow spaces between them as observed by SEM. The ciliary cleft appeared quadrilateral and contained large amount of trabecular tissue that could be divided into two parts, the uveal part and the corneoscleral part. The uveal meshwork was the internal part of the trabecular meshwork. It occupied wide area in the anterior region and narrow area in the posterior one. It composed of thick-pigmented trabeculae in the anterior part, which became thin and loose in the posterior part. Their intertrabecular spaces were large and wide anteriorly. The corneoscleral meshwork was the external part of the trabecular meshwork. It was narrow anteriorly and widened posteriorly. Their trabeculae were non-pigmented and closely arranged and the intertrabecular spaces were small. The angular aqueous plexus consisted of four to five veins. They were located between the outer border of the corneoscleral meshwork and the inner border of the sclera. These results of the iridocorneal angle suggest important implications for understanding the glaucoma disease in buffaloes.

Animals↗

PubMed1986

Postmortem examination of incinerated teeth with the scanning electron microscope.

Fragments recovered from the burned wreckage of a gasoline truck and thought to be parts of teeth were confirmed as such after they were examined with a scanning electron microscope. The appearance of the fragments was compared with previously published descriptions of teeth which had been incinerated under laboratory conditions and also examined by scanning electron microscopy.

Accidents, Traffic↗

PubMed1986

A simple method for correlative light, scanning electron microscopic and X-ray microanalytical examination of the same section.

Thin paraffin sections, mounted on scanning specimen holders previously coated with polyester film tape (Minnesota Mining and MFG Co., Scotch film tape No. 850 gold), were processed for light microscopy (LM) in the conventional way, then covered with celloxin shellac and examined in the LM by using the upper illuminating source. After removal of the shellac from the surface of the sample by immersion in acetone, the sections were air-dried, coated with a copper layer in a vacuum evaporator and examined in a scanning electron microscope (SEM). The method allows: (i) high-quality LM possibilities for establishment of the diagnosis in pathological cases; (ii) SEM examination of the same area as observed in LM; and (iii) EPMA measurements of insoluble precipitates embedded in the tissue. The usefulness of the proposed method is obvious in cases where the composition of a precipitate on LM scale is to be compared with the LM appearance of the surrounding tissue.

Animals↗

PubMed1993

Dentinal wall adaptation of thermoplasticized gutta-percha in the absence or presence of smear layer: a scanning electron microscopic study.

The dentinal adaptation of injected thermoplasticized gutta-percha and thermoplasticized gutta-percha resulting from Ultrafil and Thermafil systems was evaluated by scanning electron microscopy and compared with adaptation obtained with the lateral condensation of gutta-percha. Each method was evaluated with and without the smear layer removed. Scanning electron microscopic observations showed the thermoplasticized gutta-percha resulting from either system to have better dentinal wall adaptation than lateral condensation of gutta-percha in either the absence or presence of the smear layer. In the absence of smear layer, the adaptation of gutta-percha was improved in all groups. Although sealer was used, removing the smear layer was found to enhance the ability of the thermoplasticized gutta-percha to enter the patent tubules.

Dental Pulp Cavity↗

PubMed1975

A scanning electron microscopic study of platelets of certain animal species.

Comparative morphology of platelets of the dog, cat, cow, horse, sheep, and goat was studied with the scanning electron microscope and was found generally similar. Most of the platelets were slightly biconvex of flat with relatively smooth surface and even contour. Some of these platelets had few short marginal filaments, oriny protuberances on the surface. A small number of platelets exhibited surface irregularity and few long pseudopods which were thought to result from platelet activation during the processing of blood. The number os such irregular platelets increased in stored blood and in blood fixed at 4 degrees C.

Animals↗

PubMed1989

Scanning electron microscope study of Torulopsis ethanolitolerans prepared by glutaraldehyde--thiosemicarbohydrazide procedure.

Torulopsis ethanolitolerans subject to both the sparing and coarse heat treatment were studied in the scanning electron microscope. The reduction of adhesivity, increased permeability and higher rigidity of the yeast wall was achieved by an original glutaraldehyde-paraformaldehyde fixation, low osmolarity in vacuo and subsequent thiosemicarbohydrazide incubation, followed by addition of metal salt. The impregnation of the metal throughout the specimen due to the reaction of the thiosemicarbohydrazide with glutaraldehyde allowed viewing of small or intricate surface details of the yeast. Structural differences of the yeast processed by sparing and coarse heat treatment were shown to be better from the thiosemicarbohydrazide incubated samples compared to those that were prepared with osmium tetroxide.

Candida↗

PubMed1974

Morphological alterations of Pseudomonas aeruginosa by ticarcillin: a scanning electron microscope study.

Pseudomonas aeruginosa was exposed to 0.1, 1.0, 10, 100, and 1,000 times the minimal inhibitory concentration of ticarcillin in vitro and subsequently examined with the scanning electron microscope. The morphological alterations observed were filamentation, mid-cell defects, and spheroplast formation, and these alterations were dependent upon the drug concentration.

Carboxylic Acids↗

PubMed1995

Scanning electron microscopic observations on gastric mucus secretion in rats, and the effects of tetraprenylacetone.

Mucus secretion in the gastric mucosa of rats was studied with a scanning electron microscope. After stimulation, two types of mucus secretion were observed: exocytosis and apical expulsion. Prolonged administration of tetraprenylacetone (TPA) significantly increased the number of mucus-secreting cells in both the gastric corpus and antrum 12 h after the last administration of TPA. In the secreting cells, apical expulsion was significantly more frequent among TPA-treated than in untreated rats. TPA also significantly increased the hexosamine concentration in both gastric corpus and antrum. These findings indicate that TPA stimulates both the content and the secretion of gastric mucus, and that its secretion is chiefly through apical expulsion.

Animals↗

PubMed1994

[Scanning electron microscopical study of trachea vasculature in the human fetus].

The microvasculature of the human fetal trachea was studied in vascular casts viewed in a scanning electron microscope (SEM). The trachea is supplied by longitudinal vascular bundles running at both sides of the organ, including both longitudinal tracheoesophageal arteries and veins. They are the source of the segment vascularization of the trachea. Due to numerous arteriovenous anastomoses and anastomoses occurring within respective arterious and venous vascular systems, a constant blood flow within submucous capillary plexus and the tracheal wall is provided. A characteristic feature of tracheal vascularization is a very rich, dense network of vein.

Corrosion Casting↗

PubMed1987

Human kidney glomeruli, with special reference to those in the aged person: scanning electron microscopic study of microvascular corrosion casts.

Blood vascular beds of fetal, adult and aged human kidneys were reproduced with methyl methacrylate and observed with a scanning electron microscope. The kidney glomeruli, including those from the fetal kidneys, had anastomosing capillaries. The glomeruli in the kidneys of an aged person contained many more capillaries which were much more tortuous than those of the adult and fetal kidneys. Furthermore, it was observed that the glomeruli in the kidneys of the aged person usually received tortuous afferent vessels and frequently emitted multiple efferent arterioles. The glomeruli in the juxtamedullary layer of the kidneys of the aged person were rather small in size and contained degenerative capillary networks. This observation suggests that the medulla of the kidneys of the aged is poorly supplied with blood.

Adult↗

PubMed1981

[Method of studying internal tissue structure under the scanning electron microscope with frozen and paraffin sections].

Frozen and paraffin sections may be used for the study of the inner structure of organs and tissues in scanning electron microscope; this increases the value of this instrument and gives a lot of new information. The new method gives a good view of the alveolar (arch) structure of the heart valves which appears to be the morphological foundation of their durability and elasticity. There are reasons to believe that connective tissue in different parts of the body is characterized by the alveolar (cellular) structure which seems to be the morphological foundation of its supporting function. The dynamic loading forms and creates the organ specificity of the connective tissue stroma. Like honeycombs, the connective tissue consists of cells the formation of which is significantly affected by the features of dynamic loading on the tissue or and organ.

Coronary Vessels↗

PubMed1999

[Scanning electron microscope observation on endosperm starch grain characters in multiplasmic maize].

In this article, endosperm starch grains of eleven lines in multiplasmic maize were studied by scanning electron microscope. The results show that different cytoplasm has different effects on the characters of starch grain. The starch grains of three sweet corn cytoplasmic lines (su1, sh2, btl) are mainly spherical and packed tightly, which means they have some degree of similarity. While the grains of four cytolasmic male sterility lines (T, S, C, 21A) are mostly irregular and packed loosely except (T) Mo17, in which grains are tightly packed. The average diameter of these eleven varieties is ranged from 9.78 microns to 14.69 microns. Through the study of endosperm starch grain shape and size, we tried to explore the relationship between the property of starches and the quality of seeds. And this will significantly prompt the development of maize genetics and breeding.

Fertility↗

PubMed1990

Scanning electron microscopic studies and x-ray microanalysis of hyaline bodies in odontogenic cysts.

70 odontogenic cysts with hyaline bodies (HB) were examined by light and scanning electron microscopy. The scanning electron microscopic studies were performed on dried tissue material, which had been previously examined by light microscopy and energy dispersive x-ray analysis of the histologic sections. The form and basic structure of both the early forms of HB as well as the HB Type I and II could be identified more closely. The early forms, the outer component of the HB Type II and the inner and outer component of the HB Type I consisted of a fine-grained substance, which presumably goes through varying "partial homogenization", thus giving the HB an increased firmness and elasticity. The HB are a product of the epithelium of odontogenic cysts and have direct contact to the outer layer of the adjacent cyst epithelium via its intercellular bridges.

Calcium↗

PubMed1978

[Scanning electron microscopic study of the changes of the luminal surface of rat thyroid epithelial cells following exposure to cold for 6 to 48 hours (author's transl)].

Scanning electron microscopic observations of thyroid follicle cells of rats exposed to 4 degrees C for 6 to 48 hours were found to show an increased number of apical microvilli in comparison to those of controls kept at 22 degrees C. These ultrastructural differences--which were statistically significant 48 hours after start of the experiments--are related to stimulation of thyroid gland activity by exposure to cold.

Animals↗

PubMed1971

A scanning electron microscope study of the human glomerulus.

The three-dimensional fine structure of human glomeruli taken at autopsy and by biopsy was studied under the scanning electron microscope. The podocytes and their cytoplasmic processes in their elaborate ramification on the capillary wall were clearly demonstrated in the glomerulus of the autopsy specimens fixed by perfusion of glutaraldehyde as late as 3 hours after death, and in the glomerulus of the biopsy specimen fixed by immersion in the same fixative. The human podocytes were characterized by marked irregularity in the ramification pattern of their cytoplasmic processes, as compared with those of the rat and the rabbit. The interdigitation of the terminal processes was always noticed between those of different cells. The extended loss of the terminal processes was seen in the glomerulus of a case with severe proteinuria. The presence of intercellular spaces between the sheet-like cell peripheries of the podocytes supports the author's hypothesis in his studies on experimental nephrosis of rats that the disappearance of the terminal processes is not due to syncytial fusion of neighboring podocytes, but to retraction of swollen processes toward the central portion.

Adolescent↗