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Results for “scanning electron microscope”

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PubMed1998

The effects of a single course of a calculus-softening scaling and root planing gel. A scanning electron microscopic study.

The effect of a calculus scaling gel was evaluated as an adjunct to instrumentation in a double blind, split-mouth, clinical study. Fifteen comparable periodontally involved teeth from 5 patients were instrumented on the mesio-buccal root surface with the aid of either the test gel, placebo gel, or no gel until smoothness was achieved. Test or placebo gel was applied subgingivally for 10 minutes. Instrumentation time, ease, number of strokes, and gingival/tooth surfaces changes were recorded. Scanning electronic microscopic (SEM) evaluation of root surface topography was evaluated. The results demonstrated effective calculus removal in all treatment groups with no differences found between them. Instrumentation time, ease, and number of strokes were similar for all treatment groups. There were no harmful effects to soft or hard tissues. The results of this study do not support the use of calculus scaling gel as an adjunct to root instrumentation.

Adult↗

PubMed1976

A scanning electron microscope study of the interstitial tissue of the canine testis.

Scanning electron microscopy (SEM) is a potent tool that is especially valuable in interpreting the three-dimensional relationships of cells within tissues. This type of information is obtainable from thin sections in transmission electron microscopy (TEM) only by reconstructions of serial sections. The arrangement of the interstitial cells of the testis in relation to the capillaries and lymphatic channels, in particular, is easier to visualize in SEM than in TEM. Cytoplasmic constituents, as well as cell surface modifications, are demonstrable by this technique. The presence of droplets, presumably lipid droplets, both within and on the Leydig cells and the lymphatic endothelial cells, is quite evident. Other cytoplasmic structures are also apparent. For example, the possible functional significance of "openings" that are seen by SEM on the septa that surround lipid droplets is discussed relative to the appearance of the same area as seen in thin sections or in freeze-fracture replicas. SEM should become a very useful method for studying cytological and morphological alterations that occur in testicular tissue that is subjected to physical or chemical manipulation.

Animals↗

PubMedDate not supplied

Scanning electron microscopic study on the effect of tunicamycin on Candida albicans.

Scanning electron microscopy was used to study the effect of tunicamycin, an inhibitor of N-glycosylation, on the morphology of Candida albicans grown in minimal essential medium Earle's base and supplemented with 0.5% N-acetyl-D-glucosamine to stimulate germ tube induction. Addition of the drug prevented development of germ tubes, development of mycelia from germ tubes and resumption of germ tube growth after drug removal. Inhibited cells increased in size during treatment and subsequently became misshapen and shrivelled with evidence of cytoplasmic spillage.

Candida albicans↗

PubMed1984

Scanning electron microscopic study of orthodontically induced injuries to the periodontal membrane.

Scanning electron microscopy was used to study vascular and cellular changes in the periodontal membrane (PDM) in rats after orthodontic treatment ranging from 3 h to 9 days. The orthodontic forces ranged between 200 mN and 400 mN. Within the first hours of treatment extravasated erythrocytes, eichinocytes and platelets in various stages of degeneration were found in the pressure zones. The connective tissue of the pressure zones developed an amorphous appearance lacking discernible fibers and blood vessels following treatment for 24 h. These areas are known as hyaline zones, an area of local aseptic necorsis. Three days after the application of an orthodontic force macrophage-like cells were abundant close to the hyaline zone. They adhered to the hyaline zone with filopods radiating from pseudopods. Large osteoclast-like cells with several projections towards the bone surface were found around the hyaline zone and in the marrow spaces close to the pressure zones. The results indicated that the tissue reactions leading to remodeling of the PDM in the pressure zones are closely related to vascular injuries and subsequent formation of coagulated blood. Furthermore, macrophages seem to be the cells which play the most important role during degradation of the hyaline zone.

Animals↗

PubMed1976

Surface ultrastructure of silicone rubber aortic valve poppetts after long-term implantation. A scanning electron microscope study of four poppets.

The surface ultrastructure, demonstrated by scanning electron microscopy, is described in four implanted Silastic aortic valve poppets. Ball variance was discovered at necropsy in two patients and clinically in one in whom the poppet was replaced. The fourth patient underwent reoperation, but ball variance was neither suspected nor found. All four poppets were densely coated with biological debris and microthrombi. The 'coat' was soluble in a weak solution of sodium hydroxide. The true Silastic surface beneath the coat was little altered compared with unimplanted poppets, even after 10 years' implantation.

Adult↗

PubMed1976

Cell organelles at uncoated cryofractured surfaces as viewed with the scanning electron microscope.

A method of direct visualization of cell organelles by scanning electron microscopy (SEM) is described. Plant and animal tissues fixed in glutaraldehyde and osmium tetroxide are treated with the ligand thiocarbohydrazide and a second osmium tetroxide solution, to increase their osmium content. Tissues are then dehydrated, infiltrated with an epoxy monomer, and together solidified with dry ice and fractured. The pieces are transferred to pure acetone, critical-point dried, attached to stubs with silver paint and viewed by SEM. The ligating procedure increases the osmium concentration at its original bonding site sufficiently to render the tissue electrically conductive, thus obviating the need for metallic coating. he organelles at the fractured surface are revaled in relation to their osmium incorporation rather than by surface irregularities as with coating methods. The image derived from the uncoated surface approaches in resolution that of transmission electron micrographs of thin sections. A protion of the image arising from a small distance below the surface, while at progressively lower resolution, provides some 3-dimensional information about cell fine structure.

Animals↗

PubMed1992

Incomplete vascular casting for a scanning electron microscope study of the microcirculatory patterns in the rat pancreas.

Scanning electron microscopy of resin casts prepared by incomplete arterial injections showed that in the rat pancreas, the casting medium fills blood capillaries in the endocrine islets more promptly than those in the exocrine lobules and secretory ducts. Furthermore, the exocrine lobules containing endocrine islets allowed a more rapid resin flow through the insulo-acinar portal route than those lobules lacking an islet. The secretory ducts were the last portions to be filled with resin. Since the resin medium used in this study was as viscous as blood and injected under a physiological pressure, the microcirculatory modes demonstrated by the present method suggest the physiological flow of blood in the rat pancreas.

Animals↗

PubMedDate not supplied

A scanning electron microscopic study of different caries removal techniques on human dentin.

Scanning electron microscopy (SEM) evaluated the effect of different caries removal techniques on human dentin topography. Thirty-six extracted human carious mandibular molars were randomly assigned to six groups according to caries removal technique. Carious tissue was removed by hand excavation, bur excavation, air-abrasion, laser ablation, chemomechanical methods and sono-abrasion. The remaining dentin surfaces were replicated and gold-coated. The surfaces were examined using SEM and distinct differences in appearance were observed among specimens treated with different caries removal techniques. While hand-excavated, bur-excavated and air-abraded carious dentin surfaces were covered with a residual smear layer, sono-abrasion with patent dentinal tubules completely removed the smear layer. A few patent orifices of dentinal tubules were observed in dentin subjected to laser ablation and chemo-mechanical caries removal.

Adult↗

PubMed1990

Scanning electron microscopic studies of the oral tissue responses to dental implants.

Scanning electron microscopy (SEM) and its associated technologies have proven invaluable in elucidating the interfacial oral tissue responses to dental implants. Since the dental implant must extend from the mandibular or maxillary jaw, through the oral mucosa, and into the oral cavity, these tissue responses include epithelium, connective tissue and bone. The continual occlusal forces acting upon these tissues reinforce the dynamic character of these tissue responses. Immediately upon implantation, a healing phase begins as a response to the implanted biomaterial. Following this immediate response a longer healing phase occurs, beginning approximately 1 week after implantation, resulting in the modeling of bone to the implant as well as the formation of epithelial attachment to the implant. This later, delayed healing continues throughout the lifetime of the implant since these tissues must die and be replaced by similar tissues. Current dental research employing scanning electron microscopy is now documenting these tissue responses. This paper reviews, in detail, SEM observations of these tissue responses.

Animals↗

PubMed1987

Myogenesis in vitro as seen with the scanning electron microscope.

In this paper, we review our recent observations by scanning electron microscopy (SEM) on the differentiation of the cell surface and cytoplasmic organelles in embryonic chick skeletal muscle cells in vitro. The changes of the surface structures of myoblasts during mitosis were essentially similar to those of other cell types, but the characteristic spindle shape of myoblasts did not change throughout most of this period. Cytoskeletal structures under the sarcolemma were examined by Triton extraction and metal coating. Cells in S, G2 and M possessed a dense, and those in G1 a loose filament network under the membrane. Myotubes possessed a dense network under the sarcolemma. In the fusion area between a myoblast and a myotube, the cytoskeletal domain of the former could be distinguished from the latter because of the mosaic appearance of the subsarcolemmal cytoskeletal network. This network was composed predominantly of 10-13 nm filaments; they were identified as actin filaments because of their decoration with myosin subfragment-1. Triton treatment and thiocarbohydrazide-osmium staining allowed us to visualize myofibrils. They ran in the direction of inferred stress lines brought about by elongation and adhesion of the cells to substrate. Intracellular membranous organelles could be seen by the freeze-polishing and osmium-maceration procedure. Mitochondria exhibited complex irregular branchings. T system tubules ran a tortuous course. Sarcoplasmic reticula with occasional dilatations were connected to each other. The results are of sufficient promise to encourage more extensive analysis of myogenesis by SEM.

Animals↗

PubMedDate not supplied

The nasal mucosa during long-term treatment with beclomethasone dipropionate aerosol. A light-and scanning electron microscopic study of nasal polyps.

Blind examination by light- and scanning electron miscroscope of a total of 142 biopsies from nasal polyps was carried out before and after continuous intranasal treatment with beclomethasone dipropionate aerosol, 400 microgram/day, for a period of 9-36 months. The degree of tissue oedema, the number of infiltrating eosinophil cells and the number of goblet cells in the epithelium decreased significantly. There was no change in the type of surface epithelium during treatment, and no tendency towards squamous cell metaplasia. The study suggests that beclomethasone dipropionate treatment for a period of a few years will not cause atrophic rhinitis.

Aerosols↗

PubMed1982

[Potentials of a scanning electron microscopic method in studying dressing materials].

The possibilities of the scanning electron microscopy (SEM) technique were evaluated in the studies of functional properties of dressing materials. It was shown that the use of SEM enables the disclosing of the effect of structural characteristics of the dressing materials on their atraumaticity, the appraisal of the absorption capacity of the dressings, and the exploration of the time course of wound healing under the dressings.

Bandages↗

PubMed2003

Scanning electron microscopic study of the cleaning ability of chlorhexidine as a root-canal irrigant.

AIM: To evaluate in vitro the cleaning of root-canal walls after irrigation with different irrigants. METHODOLOGY: A total of 36 recently extracted human teeth were divided into four experimental groups according to the irrigating solution used: saline; 2% chlorhexidine; 2.5% sodium hypochlorite; and 2.5% sodium hypochlorite + EDTA. The cleaning of the apical, middle and coronal thirds of the root canals was evaluated by scanning electron microscope examination using a 4-point scoring system. RESULTS: The best cleaning was obtained using 2.5% sodium hypochlorite and EDTA, followed by 2.5% sodium hypochlorite only (P < 0.05), whose cleaning was similar to chlorhexidine only in the cervical third. Cleaning by saline and 2% chlorhexidine was worse than the other two groups and was similar in all thirds. Better cleaning was found in the cervical and middle thirds for all groups with the worst results in the apical third. CONCLUSIONS: The apical third of the root canals was not cleaned as well as the middle and coronal thirds. Cleaning by chlorhexidine and saline was inferior compared to the cleaning by sodium hypochlorite with and without EDTA.

Analysis of Variance↗

PubMed2005

The effect of two different demineralization methods with saturated tetracycline hydrochloride on the attachment and growth of gingival fibroblasts. A scanning electron microscopic study.

The purpose of the present study was to evaluate in vitro, the influence of two different methods of surfaces conditioning of dentin by tetracycline hydrochloride on human gingival epithelial cell attachment. A flat dentin surface was created on human teeth extracted due to severe periodontitis: 36 specimens were divided into 3 equal groups and etched in the following way: group 1 (saline); group 2 (immersion in TTC for 3 min); group 3 (burnishing with TTC for 3 min). The specimens and fibroblasts were incubated in a culture medium for 24 hours, one and two weeks and photographed using scanning electron microscope. No fibroblasts could be seen on the saline groups. More fibroblasts could attach to the root surface at one and two weeks irrespective of the method used.

Administration, Topical↗

PubMed1994

Microvascular anastomosis of interpositional vein grafts with sutures and a new mechanical device--a histologic and scanning electron microscopic study.

In an experimental study, a new mechanical device for microvascular anastomosis was compared with suture anastomosis. In 14 rabbits, seven end-to-end and seven end-to-side anastomoses of the jugular vein to interpositional vein grafts were done with a ring-pin device and by the conventional suture method. There was no significant difference between the patency rates of mechanical and suture anastomoses. The completion of mechanical anastomoses took one-third the time required for suture anastomoses. After 10 days, histologic and scanning electron microscopic examination revealed an uneventful reparative process at the anastomotic site with media atrophy and a continuous endothelial layer. At 4 weeks, occasional foreign body giant cells were seen between the polyethylene rings and surrounding connective tissue. The study confirms that the ring-pin device is safe and provides a faster way to do microvascular anastomoses than by suturing.

Anastomosis, Surgical↗

PubMed2000

Scanning electron microscopic studies on morphological abnormalities of erythrocytes in alcoholic liver diseases.

BACKGROUND: We previously reported that morphological abnormalities and the altered deformability of erythrocytes play important roles in disturbances of hepatic microcirculation associated with alcoholic liver disease. METHODS: The subjects of this study were five patients with alcoholic liver cirrhosis, two patients with alcoholic fatty liver, and two healthy volunteers. Concentrating on erythrocyte morphology in the presence of alcoholic liver disease, we observed erythrocytes under a scanning electron microscope and examined their morphological changes in relation to the disease. RESULTS: Among the five patients with alcoholic liver cirrhosis, stomatocytes accounted for about 14% and acanthocytes for about 10% of all erythrocytes. In the fatty liver group (n = 2), acanthocytes were absent, and stomatocytes accounted for 23% in one subject and 56% in the other, of the total. When the two patients with liver cirrhosis were examined over time, one of them was found to have 12% stomatocytes, 21% acanthocytes, and a filtration time of 14.7 sec at admission. Following 1 month of abstinence, this patient had 1% stomatocytes, 6% acanthocytes, and a filtration time of 10.4 sec, which were accompanied by improvements in peripheral blood parameters and liver function. In another patient with liver cirrhosis, there were no acanthocytes, 8% stomatocytes, and a filtration time of 5 sec at admission; this patient had 1% stomatocytes and a filtration time of 7.7 sec after 1 month of abstinence. In one patient with fatty liver who was examined over time, the percentage of stomatocytes was 56%, and the filtration time was 7.7 sec at admission; these parameters were 1% and 5.1 sec, respectively, after 1 month of abstinence. CONCLUSIONS: The present study revealed that stomatocytes and acanthocytes are morphologically abnormal erythrocytes observed in the presence of alcoholic liver disease. These abnormal forms of erythrocytes tended to normalize as peripheral blood parameters and liver function were improved by abstinence, which suggests that erythrocyte morphology is related to the pathophysiology of alcoholic liver disease.

Acanthocytes↗

PubMed2000

Angioarchitectural form, functional distributive pattern and classification of the filiform papillae on the crossbred Japanese cat tongue anterodorsal surface in scanning electron microscopic specimens.

The purpose of this study was to undertake a three-dimensional comparative observation of the angioarchitectural form, functional distributive pattern and classification of the filiform papillae (FiP) as they appear on the entire dorsal surface of the front of the Japanese cat tongue using microvascular cast specimens (MVCS). By means of the corrosive resin casting technique, the MVSC of the FiP of the cat tongue were prepared and examined in detail under the scanning electron microscope (SEM). On the frontal half of the anterodorsal surface of the anterior tongue, types I-V of the FiP are arranged in the form of a A with the point in the direction of the apex and in an oblique line running from the antero-central to both postero-peripheral regions. In the rear half of the anterodorsal surface of the anterior part of the tongue, types I-V of the FiP are arranged in the form of a V with the point in the direction of the root and in an oblique line running from both antero-peripheral regions to the postero-median region or towards the pharynx on the anterior centro-dorsal surface of the tongue. The FiP, arranged in an oblique line running fron the central to the apical part of both the periphery and the pharyngeal region of the cat tongue, can be classified into five types (Types I-V) according to the shape and size of the main process (MP), numbers of the accessory processes (AP) and regional position of the lozenge arrangement. FiP Types I-III consisted of an MP which contained a large spoon-shaped and concave network process, and the AP contained a bundle of spin-like processes arranged radially at the anterior basal margin of the MP. FiP Types IV and V consisted only of MP. It was conjectured that the lozenge arrangement of the A and V form FiPs, classified into five types (Types I-V) from the frontal portion of the anterodorsal surface toward the pharynx on the front of the tongue, play a functionally assistant role in the mastication of food and sucking of liquid, including milk.

Animals↗

PubMed1998

Scanning electron microscopic study of erythrocyte shapes artificially jetted through tubes at different pressures by 'in vitro cryotechnique for erythrocytes'.

A new cryotechnique for examining morphological changes of human erythrocytes at different jet pressures was developed in the present study. Human fresh or stored erythrocytes passing through a tube were jetted into precooled isopentane-propane mixture (-193 degrees C), which was named as 'in vitro cryotechnique for erythrocytes'. After the cryotechnique procedure, the routine freeze-substitution method and subsequent t-butyl alcohol freeze-drying method were used for preparing the scanning electron microscopic specimens. At 100 mmHg or higher pressures of jetting, lamellar-arranged erythrocytes were observed to have elongated shapes. The more the jetting pressure increased, the fewer discoid shapes of erythrocytes were observed. This cryofixation technique could preserve the morphology of erythrocytes jetting from tubes, and provide the three-dimensional image of erythrocyte surfaces, as followed by scanning electron microscopy.

Erythrocyte Deformability↗