PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “scanning electron microscope”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12Linked to original sources
PubMed1985

Scanning electron microscopic observations of casts of human dentinal tubules along the interface between primary and secondary dentine.

A scanning electron microscope cast technique was used to examine the interface between primary and secondary dentine in young and old human teeth. In addition, more traditional methods were used to examine this interface with light microscopy, identical regions being viewed before and after demineralization. No continuity was seen between the tubules in primary dentine and those in irregular secondary dentine in the scanning electron microscope preparations. These preparations did show the tubules to be continuous between primary dentine and regular secondary dentine in young and old teeth. Both the scanning electron microscopic and light microscopic observations suggested that regular secondary dentine becomes highly sclerosed in old teeth.

Adult↗
PubMedDate not supplied

A scanning electron microscopic study of the normal human stapes.

The structure of the normal human stapes was studied with the scanning electron microscope. Specimens were obtained 48 hours after death from adult human temporal bones free from obvious inflammatory disease. The specimens were fixed, dissected, critical-point dried and coated with gold. In this scanning electron microscopic study an attempt has been made to systematically demonstrate the average scanning electron microscopic features of various areas of the normal human stapes. An emphasis has been placed upon demonstrating as clearly as possible the details previously unclear or unrecognized and duplication of many excellent earlier light and electron microscopic studies has been attempted. The typical appearance of the stapes head, neck, arch, crura and footplate has been presented. It is apparent that there exists a high degree of structural specialization particularly in the stapes arch and footplate area.

Ear Ossicles↗
PubMed1991

Investigations of the course of post-partum period in the merino Polish sheep. IV. Shifts in the intercaruncular regions of uterus (observation in light microscope--LM and in scanning electron microscope--SEM).

Studies on the intercaruncular regions of uterus were carried out on 34 ewes on Days 1-78 of the post-partum period to determine the approximate date of ending post-partum changes and the appearance of morphological sings interrelated with the ovarian cycle phases. It was demonstrated that in sheep the remodelling of endometrium relief lasted until Day 12 of post-partum (p.p.) and at the same time destruction changes in the superficial and glandular epithelium, as well as in the uterine stroma ended. At first, changes in the myometrium (around Day 6--in the longitudinal layer and on Day 10--in the circular layer) were finished. After Day 12 p.p. there was a number of morphological signs indicating the relationship between the ovarian cycle phase and changes in the endometrium of intercaruncular regions of the uterus. At the same time, the role of stromal leucocytes and certain hormones in processes of the involution of uterus was discussed.

Animals↗
PubMed1988

Changes in soft palate taste buds of rats due to aging and zinc deficiency--scanning electron microscopic observation.

The effects of aging and zinc deficiencies on taste were studied. The soft palate of zinc-deficient old rats, prepared by feeding with a zinc-deficient diet, were studied by a light microscope and a scanning electron microscope, and comparative examination was made on the morphological changes in soft palate papillae and taste buds of young normal rats and control old rats. In the case of young normal rats, papillae similar to lingual fungiform papillae were observed on the soft palate; one taste bud per one papilla was observed. The papillae were concentrated in the central area of the soft palate continuing from the hard palate. In the case of old rats, decrease in the number of papillae, flattening of papillae, exfoliation and atrophy of mucosal epithelium and leveling of microplicae were observed. In the case of zinc-deficient old rats, the above-mentioned tendencies were more significant. While dense substance and microvilli were observed in taste pores of taste buds of young normal rats, these were found to decrease or disappear in the zinc-deficient old rats.

Aging↗
PubMed1981

Scanning electron microscopic evidence of bacterial overgrowth in intertrigo.

A scanning electron microscopic (SEM) study of intertrigo is presented. Marked changes of the keratinocyte surface characteristics and in the number and distribution of bacteria in the various stages of intertrigo are reported. Bacterial overgrowth was significant. This study confirms the value of SEM in the study of the skin surface and in cutaneous microbiology.

Adult↗
PubMedDate not supplied

Study on the normal and pathologic structures of the hard dental tissues using the scanning electron microscope.

The recent use in biology of the Scanning Electron Microscope allows a new vision of the sample, completing the previous ones: the Optical Microscope (OM) and the Conventional Electron Microscope--CEM. The object is observed in space, in a direct way and, due to a system of variable sizes, the passage from a general image to the detailed tissue and cell study is permitted. The outer enamel surface with its perikymaties, its flaws and its changes caused by usage as well as by the internal enamel structure on the fractured area have been studied. On the occlusal surface of the decayed teeth, focal holes have been found; they resulted probably from creation disturbances due to some amelogenetic disorders that damage the ameloblast, matrix creation or its mineralization. These lacunar flaws are the favourite zones for the microbe plate accumulation and propitious to carious lesions initiation. The same clinical aspect, of profound enamel creation defects with an anfractuous crevass network aspect, having a variable expansion and depth, can be found in microscope with some healthy teeth. Regrouping in fascicles of the different prism directions can be found after structural analysis of the prismatic morphology of the parodontotic tooth enamel. An aspect of a more compact structure is thus obtained sectionally. This explains partially the increased resistance to decay of these teeth. In a comparative study of the fractioned area of some decayed and ruined temporary teeth, significant differences in prism arrangement can be found. The decayed teeth show expansions of the intraprismatic spaces, accusing reduced resistance against decay attack.

Dental Enamel↗
PubMed1991

Microvascular structure of the larynx. A scanning electron microscopic study of microcorrosion casts.

In this study, scanning electron microscopic observations were made of the microvasculature of the larynx of guinea pigs, rabbits and humans. The results showed that 1) The epiglottis being the most abundant of all laryngeal structures in vascular plexus, with some of the vessels perforating cartilage; 2) Blood vessels of the vocal cord course along its long axis showing undulation; arteriovenous anastomoses was noted; 3) In the arytenoid, blood vessels were found to be irregularly coursing and tortuous, thereby facilitating the purpose of smooth movements of this structure.

Animals↗
PubMed1981

Ruthenium red-mediated osmium binding for examining uncoated biological material under the scanning electron microscope.

A simple technique for examining uncoated soft biological material under the scanning electron microscope is described. Rat tissues were initially fixed in 2.5% glutaraldehyde either by intravascular perfusion or by immersion. The samples were placed in buffered 2.5% glutaraldehyde containing 0.05% ruthenium red and postfixed in buffered 1% osmium tetroxide containing 0.05% ruthenium red. The samples were alternately incubated 3 to 5 times in 1% OsO4 and 0.1% ruthenium red solutions with continuous shaking at room temperature. The specimens were dehydrated, critical point dried, mounted and examined under the scanning electron microscope. Contour details were clearly defined at both the external and cut surfaces of the tissues. The specimens could be observed for more than 30 minutes without excessive charging or glow effects and the material remained stable under the beam at 20-25 kV and at various magnifications.

Animals↗
PubMed1987

Exposure of vascular smooth muscle cells for analysis with the scanning electron microscope.

There has been interest in using the scanning electron microscope (SEM) to study the structure of tissues obscured by other cellular or non-cellular elements almost since the SEM was first used to examine biological tissues. Such interest includes the vessel wall and, in particular, the vascular smooth muscle cells. This paper presents a review of the three basic methodologies that have been employed to allow examination of the vascular smooth muscle, 1) blunt dissection, 2) digestion and 3) microdissection. Discussion of other perivascular elements was not a focus of this review. Also presented is the application of these different methodologies to different pathophysiologic conditions.

Animals↗
PubMed1998

Roller pump induced tubing wear of polyvinylchloride and silicone rubber tubing: phase contrast and scanning electron microscopic studies.

Tubing wear and spallation have long been recognized as complications of roller pumps used in cardiopulmonary bypass (CPB) although the reported results of studies of polyvinylchloride (PVC) and silicone rubber tubing wear are still controversial. We conducted phase-contrast microscope (PCM) and scanning electron microscope (SEM) studies of roller pump induced tubing wear. A closed CPB circuit was constructed, and both PVC and silicone rubber tubing (1/2 inch internal diameter [ID]) were tested under normal and tight occlusions of a dual roller pump at a typical CPB flow rate (4,500 ml/min) for 1, 2, 4, and 6 h in quintet. After each pump run, the tubing was removed. It was first examined with PCM, and suspicious portions were then analyzed in detail using SEM. In silicone rubber tubing of longer running time, the external diameter often decreased. Wear was invariably found on the luminal surfaces at the junction of the inner and outer walls of both the PVC and silicone rubber tubing with no significant differences between normal and tight occlusion. The grooves in the PVC tubing were narrow and continuous with occasional deep cracks in the tubing after more than 3 h of pump run. The grooves in the silicone rubber tubing were wide and often interrupted with occasional V-shaped elevated areas. Craters of less than 50 microns occurred sporadically in both types of tubing. Neither PVC nor silicone rubber tubing offers advantages in terms of roller pump induced tubing wear and spallation.

Cardiopulmonary Bypass↗
PubMed1986

Effect of mercury on the fish (Alburnus alburnus) chemoreceptor taste buds. A scanning electron microscopic study.

Taste buds (TBs) were investigated by scanning electron microscope on various parts of the oral cavity of the bleak. (Alburnus alburnus) after differently long exposures to mercury (300 micrograms/l Hg++). This low concentration of mercury did not result in lethal effect on the bleak even after 19 days long exposure, but produced morphological changes on the TBs, which showed duration dependency. The first sign of the morphological alteration on the TBs was observed after three days long exposure, when the microridge system of the epithelial cells became damaged and the mucus secretion increased on the apical surface of the TBs. On the TBs exposed for 10 days swollen microvilliar tips of the sensory cells could be observed besides the damage of the epithelial microridge system. On the TBs exposed for 19 days degenerative changes were detected on the microvilliar system of both the supporting and receptor cells. By this time completely degenerated TBs were frequently observed.

Animals↗
PubMed1989

Scanning electron microscopic observations of adult Baylisascaris procyonis (Nematoda).

The scanning electron microscope was used to illustrate the microtopographic features of the caudal end of adult male Baylisascaris procyonis. The male tail was relatively long, smoothly attenuated and often had a small button-like or mucronate termination. The preanal papillae were situated ventrally in two slightly divergent and somewhat irregularly spaced rows. Anterior and posterior to the anus were two slightly raised roughened patches consisting of several rows of small spines. Just anterior to the anus along the outer margin of the preanal roughened patch was a large double medioventral papilla. There were five pairs of postanal papillae with the first pair just posterior to the anus being double while the remaining four pairs were more closely associated in a group near the tail end. The second pair were also double papillae; however, in a few specimens they were not fused and appeared as two single closely associated papillae. The last three pairs of papillae were single. The fourth pair of caudal papillae were the phasmids and in the center of each was a ringed pore-like opening. The spicules of the male had a highly sculptured surface with a pincher-like terminal end.

Animals↗
PubMed1989

Proximodistal gradients of the postjunctional folds at the frog neuromuscular junction: a scanning electron microscopic study.

Frog endplates were studied with the scanning electron microscope following the removal of the presynaptic terminal by collagenase and acid treatments. Endplates had 2-14 branches of primary cleft. The longest branches were parallel to the muscle fiber. Short branches oblique or perpendicular to the muscle fiber were also present near the central region of the endplates. The openings of postjunctional folds in the primary cleft were clearly visible at the bottom of the primary cleft and could be counted and measured. The longest primary cleft branches of each endplate were divided into segments of 20 microns (length corrected for shrinkage). The number of postjunctional folds per micrometer of primary cleft, the average postjunctional fold length (i.e. across the primary cleft) and the total postjunctional fold's length per micrometer of primary cleft were evaluated for each 20-microns segment of primary cleft. Negative proximodistal gradients were observed for these three parameters for the long branches of primary cleft, i.e. values were higher in the proximal region (near the motor axon) than in the distal region. These postsynaptic gradients probably reflect similar or smaller proximodistal presynaptic gradients for the active zones along the nerve.

Animals↗
PubMed1978

Surface morphology of mouse and rat thymic lymphocytes: an in situ scanning electron microscopic study.

The present paper deals with a scanning electron microscopic investigation which was undertaken in order to make a direct study of geometrical conformations of thymocytes, to determine the effect of external mechanical forces and finally to analyse the relation of the cell surface morphology to the differentiation and release of thymocytes into circulation. Thymocytes in situ revealed a striking polyhedral configuration with distinct edges and angles that permit a close orientation of cells in a minimum space. This conformation is probably acquired under the influence of forces in the microenvironment of the cells. The immature thymocytes in the cortex were smooth surfaced and constituted a homogenous population with regards to surface morphology except for slight variations in the size and angles of varoius facets of the polyhedra. A minority of the cell population occupying the medulla, however, exhibited a departure in possessing surface undulations and stubby protuberances. Thymocytes isolated in suspension and those in postcapillary venules of thymus did not show the polyhedral shape characteristic of the cells in thymic tissue. They were always rounded, with their surfaces often exhibiting undulations or microvilli. The variations observed in situ are discussed in light of external mechanical forces, cell surface characteristics and the inherent properties of differentiating thymocytes.

Animals↗
PubMed1997

The effects of different tetracyclines on the dentin root surface of instrumented, periodontally involved human teeth: a comparative scanning electron microscope study.

This in vitro study compares, by scanning electron microscope (SEM) examination, the surface effects of various topical applications of tetracycline on the instrumented dentin root surface of human teeth. Eighty-two (82) dentin samples were prepared from periodontally-compromised teeth planned for extraction. Solutions of tetracycline HCl, doxycycline, minocycline, sumycin, and a saline control were prepared and applied to the dentin samples for 0.5, 1, 3, 5, and 10 minutes. Each solution pH was measured: tetracycline HCI (pH 1.6), doxycycline (pH 2.2), minocycline (pH 3.8), sumycin (pH 4.4), and saline (pH 5.1). A tetracycline periodontal fiber was also evaluated at 1, 4, 7, and 10 days of exposure for dentin surface effects. Tetracycline HCI removed the dentin smear layer leaving clean and open tubules significantly better than other solutions tested in as little as 30 seconds. Doxycycline and minocycline produced similar results to each other, which were significantly better than sumycin and saline, but not as effective as tetracycline HCl. Smear layer removal was attained by doxycycline and minocycline in five to ten minutes; however, sumycin and the saline control ineffectively removed the surface smear layer and dentinal tubules remained partially to totally occluded by debris. The periodontal fiber did not significantly alter the surface smear layer. Results of this study suggest that tetracycline HCl is the best current tetracycline form for root surface conditioning as measured by its ability to affect both dentin smear layer removal and dentin tubule exposure.

Administration, Topical↗
PubMed1981

Scanning electron microscopic study of long flexors in human fingers.

A scanning electron microscopic (SEM) study of the digital long flexors of the human hand has provided a greater magnification and an increased resolution that facilitated the study of the architecture and the correlation of their structure to their functional activity. The observations are comparable to reports based on gross anatomic and light microscopic studies previously reported by others.

Fingers↗
PubMed1980

[Scanning electron microscopic studies of the endometrium in premalignant hyperproliferative conditions].

Scanning electron microscopic study of endometrium in premalignant hyperproliferative conditions has been carried out. Scanning and transmission electron micrographs have been correlated. It has been established that changes of the surface pattern of cells within limits indicate the process of dedifferentiation. First of all formation of cilia can be regarded as a phenomenon demonstrating malignant transformation of cells. Surface pattern of cells and intracellular processes seems to show a certain degree of parallelism. To reveal morphologic criteria evidencing malignant transformation of cells further study of the problem is needed.

Dilatation and Curettage↗