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Results for “scanning electron microscope”

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At least 127 records · Page 7Linked to original sources

PubMed1985

The cytoprotective effect of prostaglandin E2 on taurocholate-induced erosions in gastric mucosa of the rat. Light microscopic, morphometric and scanning electron microscopic investigations.

The morphological changes associated with the cytoprotective effect of prostaglandin E2 (PGE2) following sodium-taurocholate (NaTC) erosive injury in the gastric mucosa were investigated in male rats. A single topic application of NaTC (80 mMol) induced multiple gastric erosions in all animals. Application of 200 micrograms PGE2/kg body weight prior to NaTC treatment led to a significant 90% decrease in the lesion-score in PGE2-protected animals. Light microscopic morphometric studies of the mucus-producing cells in the fundus mucosa were carried out. Within the PGE2-protected animals a significant increase was observed in the length of zones of the mucus-producing cells at the surface and in the foveolae (both PAS-positive and alcian-blue-positive cells). Compared to the NaTC-injured animals, this increase amounted to 8.1% for the PAS-positive, and 6.1% for the alcian-blue-positive zone. Compared to the untreated controls, these values were 4.7% and 3.2% respectively. In the scanning electron microscope we observed a characteristic explosive release of mucus and damage of the cell's surface membranes in the NaTC-treated animals. The PGE2-protected rats showed a predominance of exocytosis of mucus vesicles which formed a characteristic mucus network at the surface membrane. Our investigations suggest that the cytoprotective effect of PGE2 may, in part, be due to an increase in mucus production and to a modification of mucus adherence at the cell membrane.

Animals↗

PubMed1980

[Morphological study of animal erythocytes using the scanning electron microscope].

The questions are discussed of erythrocyte morphology of various animal species and the changes occuring therein as a result of their ageing and pathologic and stress states. The investigation was effected with electron scanning microscope ISM-35 (IEOL--Japan). Shown are the morphologic pictures at direct fixation of erythrocytes--basic forms, sizes and percentage ratios for 8 animal species. The process of erythrocyte morophologic modifications during storage as whole blood in Olsever conservant for 168 h was studied and graphically presented. Recorded were also the changes in immunized animals and in stress state.

Animals↗

PubMed1979

[Root canal filling materials (electron scanning microscope comparison of root canal adaptation to 3 endodontic filling products)].

The main characteristics required of a good endodontic fillingsmaterial are its perfectly hermetic sealing of the root canal, the eventual secondary canals, and the dentine canals, against bacteria. 48 root canals, sealed respectively with A H 26, Endomethazone and N 2, have been checked by means of the Scanning Electron Microscope in order to discover to what extent these products conform to the qualifications mentioned. 842 photographs have been taken. The results of the investigation are discussed judging from some photographs chosen at random.

Dental Pulp Cavity↗

PubMed1982

Hard teeth tissues in rats with experimental rickets. Examinations in electron scanning microscope and microanalyser.

The experiments were carried out on Wistar rats with rickets experimentally induced. The following examinations were made: radiological examinations of the jaws, a teeth analysis in the microanalyser for the distribution of fundamental elements, and ultrastructure observations in the scanning electron microscope. The jaws of the experimental rats were smaller in the radiological picture. The disturbed arrangement of the enamel prisms was found in the enamel substructure of the experimental rats. Phosphorus values in the enamel and dentine were lower in the experimental animals. Calcium to phosphorus ratio was higher in the rachitic rats. Disturbances of calcium-phosphorus balance were observed.

Animals↗

PubMed1983

Three-dimensional visualization of Golgi-stained neurons by a projection X-ray microscope converted from a scanning electron microscope.

Trying to obtain the three-dimensional images of neuronal elements, Golgi-stained thick sections were examined by a projection X-ray microscope converted from a scanning electron microscope. An attachment unit for the projection X-ray microscope consists of a target holder, specimen stage and film cassette. Two kinds of target material, titanium and gold, were tested. The system was operated at 10 to 30 kV. The electron beam into the target was about 20 nA with the use of a pointed cathode. The stereopair of X-ray micrographs were taken by tilting the specimens. Quality and contrast of the X-ray micrograph taken with a titanium target was better than that with a gold target. The spatial resolution was estimated about 1 to 2 micrometers for 100 to 350 micrometers thick sections with a titanium target. Compared with the light microscope, strong penetrating ability of X-ray permitted to visualize the internal structures of optically opaque materials. Further, almost all objects were in focus in X-ray micrographs even for relatively thick sections (100 to 350 micrometers). The three-dimensional morphology of neurons and glial cells was demonstrated by a stereopair of X-ray micrographs.

Animals↗

PubMed1988

Scanning electron microscopic autoradiography of lung.

Scanning electron microscopic (SEM) autoradiography of the lung is being used to determine the distribution of inhaled, alpha particle-emitting, plutonium dioxide particles. SEM autoradiography provides high visual impact views of alpha activity. Particles irradiating the bronchiolar epithelium were detected both on the bronchiolar surface and in peribronchiolar alveoli. The technique is being used to obtain quantitative data on the clearance rates of plutonium particles from bronchi and bronchioles.

Animals↗

PubMed2003

[Identification of Kochia scoparia and its substitutes by scanning electron microscope and UV spectrum].

Scanning electron microscope (SEM) and UV spectrum methods were used to identify Kochia scoparia and its substitutes, including the fruits of Chenopodium album, Chenopodium serotinum and Kochia scoparia (L.) Schrad. f. trichophila Schirz. et Thell. The results showed that kochia scoparia differed from the substitutes in utride, trichome, stoma and shape of seed under SEM. The UV spectrum of Kochia scoparia was similar to that of Kochia scoparia f. trichophila, but significantly different from that of Chenopodium album and Chenopodium serotinum.

Bassia scoparia↗

PubMed1983

Investigation of articular cartilage surface morphology with a semiquantitative scanning electron microscopic method.

A semiquantitative scanning electron microscopic method for analysis of the articular cartilage surface morphology was developed. The method was based on a survey of large picture montages (ca. 70 X 100 cm) and classification of the cartilage surface changes at three levels. Computer technique was utilized in the analysis. The method ensured numerical expression and statistical treatment of the results. With this method we investigated the effects of physical exercise and immobilization on the articular cartilage of rabbit patella.

Animals↗

PubMed1975

The bronchiolar epithelium in cigarette smokers. Observations with the scanning electron microscope.

Observations with the scanning electron microscope were made on the bronchiolar epithelium of 25 lungs removed at surgery. In all but 3 cases, the lungs were removed for a malignant tumor. Abundant ciliated cells were present in all lung specimens. In lungs obtained from nonsmokers, numerous Clara cells were present in the small bronchioles, whereas goblet cells were seen, and in most cases, the Clara cells were infrequent or absent. The evidence for the secretory nature of the Clara cells is discussed as is the possible effect on lung function of alteration in the type of secretory cell in the bronchioles.

Adult↗

PubMed1988

Distribution of extrajunctional acetylcholine receptors on a vertebrate muscle: evaluated by using a scanning electron microscope autoradiographic procedure.

A scanning electron microscope (SEM) autoradiographic technique was calibrated and used to determine the site density of acetylcholine receptors within 250 micron of the neuromuscular junction in innervated as well as 3- and 10-d denervated sternomastoid muscle of the mouse. In all these groups sharp gradients of receptor site density are seen around the endplates in the first 2-7 micron, continuing less sharply to between 25 and 50 micron. Beyond 50 micron (to 250 micron) a spatial density gradient is present 3 d after denervation, but none exist by 10 d. These results suggest that the postdenervation steady-state extrajunctional receptor site density is reached sooner near the junction than away from the junction. The usefulness of SEM autoradiography to study the expression and distribution of membrane molecules at high resolution is demonstrated.

Animals↗

PubMed1984

Initial healing of the posterior corneal surface following perforating trauma in guinea pig: a scanning electron microscope study.

Using a scanning electron microscope, we have studied the healing of the posterior corneal surface after a small perforating trauma. Both corneas of adult guinea pigs were perforated with a needle and studied at various time intervals during recovery. Thirty minutes after the perforation the wound was sealed with a fibrous plug. Leukocytes adhered to the wounded area from the first day of healing on, but usually most of them disappeared after the third day. Fibroblast-like cells were present during the entire healing process from the first day on. Endothelial cells at the margin of the wound lost their hexagonal shape and began to slide over the plug. In 7 days the wound was completely covered by irregularly arranged endothelium. The endothelial cells did not reach their regular arrangement during the 14-day follow-up period.

Animals↗

PubMed1996

The hyaline zone and associated root surface changes in experimental orthodontics in rats: a light and scanning electron microscope study.

Light and scanning electron microscopic (SEM) examinations were used to study the hyaline zone and associated root resorption after orthodontic treatment of the upper first molars of rats. The orthodontic treatment consisted of a fixed buccal expansion appliance with an initial force of 250 mN. The animals were divided into nine experimental groups with orthodontic treatment and one control group without orthodontic treatment. Three groups were sacrificed immediately after 1, 3, and 7 days of treatment, and six groups after 7 days of treatment followed by 1, 2, 3, 4, 5, and 6 weeks without treatment. A hyaline zone on the pressure side of the mesial root was identified at the light microscopic level of examination as well as the SEM examination as early as 1 day after the initiation of treatment. In the SEM it was found that on the roots of teeth studied in the first few days after initiation of treatment the hyaline tissue was so firmly attached to the root that it remained in place during the extraction and preparation procedures. After longer treatment periods these hyaline zones were lost at extraction or during the preparation for the SEM examination. The cementum surface under the hyaline zone had a smooth appearance suggesting that the surface had been modified by substances released from the hyaline zone. After 1 week of treatment, resorption in the cementum could be noticed. The resorption extended to the dentine as uncovered dentinal tubuli were found. Formation of reparative cementum started two weeks after treatment. Changes in the cementum surface as well as root resorption cavities could be seen for as long as 6 weeks after the cessation of orthodontic treatment.

Activator Appliances↗

PubMed1978

Microanatomy of the human amniotic membranes. A light microscopic, transmission, and scanning electron microscopic study.

The human amnion was examined by means of light microscopy and scanning and transmission electron microscopy. The surface shows apart from microvilli a particular structure, called "blebs"; the intercellular junction is formed by desmosomes and a labyrinthine channel system, and at the base pedicels extend into the basement membrane. Cell shedding uncovers the basement membrane which seems to play a primordial role in preserving the intact amniotic cavity. These data underline the complex structure and the multiple role the amnion performs during gestation.

Amnion↗

PubMed1978

Murine macrophage-lymphocyte interactions: scanning electron microscopic study.

Light and scanning electron microscopic observations revealed murine macrophage-lymphocyte interactions involving the initial contact of peritoneal, spleen, or thymus lymphocytes with peritoneal macrophage processes or microprocesses followed by clustering of lymphocytes over the central nuclear area of the macrophages. Lymphocyte-lymphocyte clustering was not observed in the absence of macrophages. Attachment and subsequent clustering appeared not to require the presence of serum or antigen; the attachment of allogeneic or xenogeneic lymphocytes was comparable to that seen in the syngeneic system, but central clustering of these lymphocytes failed to occur. No attachment or clustering was observed when thymic lymphocytes were cultured with thymus derived fibroblasts rather than with peritoneal macrophages. Lymphocyte attachment to immune, antigen-activated, syngeneic macrophages occurred more rapidly than that to normal unstimulated syngeneic macrophages; however, lymphocytes attached to the "activated" macrophages appeared to be killed by a nonphagocytic mechanism. A similar increase in the rate of lymphocyte attachment to macrophages occurred in the presence of migration inhibitory factor. Subsequent lymphocyte clustering on macrophages was observed in the migration inhibitory factor-stimulated cultures. In addition, lymphocyte-macrophage interactions similar to those in vitro were observed to occur in vivo on intraperitoneally implanted cover slips.

Animals↗

PubMed1983

Morphogenesis of cell-to-substratum adhesion and spreading on Ni-Cr-alloys. A scanning electron microscopic study.

A scanning electron microscopy (SEM) analysis has been performed on the adhesion, spreading and growth pattern of fibroblastoid and epitheloid cells on Ni-Cr-alloys as compared to glass substrates. The attachment is initiated by filipodial contact of monolayer cells with the glass as well as alloys, and subsequent radial spreading occurs by the gradual peripheral extension of the broad lamellipodium followed by a general cell flattening. When cultured under identical conditions monolayer cells reach confluence at the same time on glass and alloy surfaces, respectively. The results show that the fibroblastoid and epitheloid cells form stable contacts between the cell surface and the alloy in the same manner in which the cells adhere to the surface of glass. The cells migrated and proliferated on the surface of alloys and covered the surface of the substratum.

Animals↗

PubMed1984

The three-dimensional configuration of the elastic fiber network in canine saphenous vein. A stereo scanning electron microscopic study.

Stereo scanning electron microscopy was used to study the normal arrangement of elastic fibers in canine saphenous veins. Selective alkali digestion and autoclaving exposed a network of interconnecting elastic fibers throughout the venous wall. 14 normal saphenous veins were surgically removed from 7 healthy dogs. Unfixed 1-cm segments of the isolated specimens were digested by sonication for 30 min in 0.5 N NaOH solution and then autoclaved for 30 min. The digested specimens were then fixed and routinely prepared for scanning electron microscopy. Large longitudinally oriented fibers in each tunica branched and anastomosed with adjacent fibers. Small fibers branched off at almost right angles and interconnected the longitudinal fibers. The configuration of the elastic network varied between the tunicae of the venous wall. The different networks were interconnected by anastomosing fibers of adjacent tunica to form a single elastic cylinder throughout the venous wall. The internal elastic lamina consisted of a single layer of fibers with a fishnet-like arrangement around the periphery of the luminal surface. Large, longitudinally oriented elastic fibers of the tunica media branched and anastomosed as in the internal elastic lamina. However, they also had tangential orientation and traversed different levels within the media. As a result, stratified layers were not formed. The external lamina consisted of several parallel layers of longitudinally oriented ribbons of elastic. Thick fibers interconnected these broad ribbons on the same and adjacent levels to form discontinuous layers. The configuration of the elastic network of the canine saphenous vein is compared to that previously reported for human saphenous vein. It is suggested that the architecture of this elastic network would contribute to vascular integrity and flexibility as well as aid in the distribution of stress throughout the venous wall. Basic knowledge of the elastic fiber network in this vein may be applied to future studies of diseased and grafted vessels.

Animals↗

PubMed1993

Effects of Nd:YAG laser radiation on removal of a root surface smear layer after root planing: a scanning electron microscopic study.

A scanning electron microscopy (SEM) study was conducted to evaluate the effects of Nd:YAG laser radiation on removal of a root surface smear layer after root planing in comparison with citric acid treatment. The experimental materials were 15 human teeth affected by severe periodontal disease, which were extracted because of a hopeless prognosis. The teeth had at least 5 mm of attachment loss on the proximal surface tested. After removing all visible calculus using an ultrasonic scaler, each proximal surface was vigorously scaled and root planed with a Gracey curet. Thirty specimens were cut from the root-planed proximal surfaces and assigned randomly to one of two groups: Group A (25 specimens) was divided into 5 subgroups and irradiated with a Nd:YAG laser, using non-contact delivery (3 mm beam diameter, distance from the tip to the specimen 5 cm), at a measured power of 20 W for 0.3, 0.5, 1.0, 2.0, or 3.0 seconds corresponding to energy densities of 84.93, 141.54, 283.09, 566.17, or 849.26 J/cm2; Group B (5 specimens) was not irradiated, but treated for 3 minutes with saturated citric acid (pH 1). The center of each specimen in Group A was used as the experimental area (Exp A) treated by laser irradiation and the peripheral area of the specimen served as a control (Cont A). In Group B, one half of the specimen was used as the experimental area (Exp B) treated by citric acid and the other half served as a control (Cont B). The specimens were then fixed and examined by SEM. The surface of the root-planed specimens (Cont A and B) was irregular, corresponding to the presence of a smear layer, and had an amorphous appearance. Both root surfaces of Exp A and B exhibited clear orifices of dentinal tubules and intertubular dentin without a smear layer. Although the root surface of Exp A showed clear orifices of dentinal tubules with a flat morphology, the root surface of Exp B showed widened funnel-shaped dentinal tubule orifices with a fibrillar, mat-like morphology. The present results indicate that Nd:YAG radiation effectively removes the smear layer, uncovers dentinal tubules, and exposes collagen fibers on the root surface without widening the orifices of dentinal tubules after root planing.

Aluminum Silicates↗

PubMed1983

Chronic nonspecific diarrhea in children: investigation of the surface morphology of small bowel mucosa utilizing the scanning electron microscope.

Investigations by scanning electron microscopy into changes of surface morphology of small bowel mucosa in children with chronic nonspecific diarrhea are reported. The study population comprised 56 patients, ranging in age from 5 months to 7 years; 65% were between 10 and 28 months old, and 64% of the patients were boys. The major findings were: microorganisms on the mucosal surface; excessive extrusion of cell cytoplasm and of enterocytes (cell shedding); presence of excessive mucus on the mucosal surface; damage to the brush border; and partial villous atrophy. The latter lesion was found in only four patients. All these changes are considered pathologic and, for the most part, are presumed to be due to the presence of antigens, in particular, microorganisms. A depression of disaccharidase activities was encountered in 64% of the patients, but prevalence was without regard to age. Most common was a combined depression of lactase, sucrase, and maltase, as well as an isolated depression of lactase. The possibility has to be considered that enteroadherent microorganisms which are usually not considered pathogenic, and microorganisms such as Mycoplasma, may emerge as intestinal pathogens in susceptible children. It is feasible that genetic traits of the host and environmental factors facilitate adherence and colonization of the small bowel mucosa which, in turn, produces chronic diarrhea. Further studies are needed to confirm the preliminary information contained in this report.

Atrophy↗