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Results for “scanning electron microscope”

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PubMedDate not supplied

Scanning electron microscopic surface topography of ablation catheter perforations and calcific tear in an explanted bioprosthetic heart valve.

The authors report a triplet of leaflet destruction in a bioprosthetic aortic valve explanted at 12 years after iatrogenic ablation catheter perforation in a patient who underwent coronary artery bypass surgery and multiple ablative procedures in the interim. Lesions were examined topographically by scanning electron microscopy. Calcium content was evaluated by mass spectrometry and Von Kossa staining. Leaflets exhibited little calcification, except at the commissures of the valve. Scanning electron microscopy revealed distinct lesion topography. The authors present the scanning electron microscopic characteristics of these lesions and of an incision into the valve made for comparison using a pair of scissors. This is believed to be the first report of scanning electron micrographs of ablation catheter perforations and a calcific tear in the same explanted valve. The findings provide a source for comparison in the etiological determination of explanted bioprosthetic valve lesions using scanning electron microscopy.

Aged↗

PubMed1990

The skeletal framework of human kidney and renal cell carcinoma. A scanning electron microscopic study.

The three dimensional architecture of the connective tissue framework of normal human kidney and three renal cell carcinomas was studied. A sodium hydroxide maceration technique was used to remove the cellular elements thus exposing the underlying connective tissue structures. The collagen fibrillar network was visualized using the scanning electron microscope. In normal kidney the fibres were fine, and smooth, and corresponded to the shapes of the original parenchymal constituents. The fibres of the kidney tumours were coarse in nature and irregularly distributed. The technique provides a rapid method for studying connective tissue fibres in normal and diseased tissue. The three dimensional architecture thus exposed enhances our knowledge of tumour stroma.

Carcinoma, Renal Cell↗

PubMedDate not supplied

Enterobius vermicularis ova in routine cervicovaginal smears. Light and scanning electron microscopic observations.

From 1971 through 1980, four Papanicolaou smears containing pinworm (Enterobius vermicularis) eggs were found among approximately 220,000 routine smears examined at the University of Texas Medical Branch at Galveston. The highest number of ova counted on one slide was 420. Typical light microscopic features of the eggs included elongated oval shapes with flattening of the ventral sides and double-contoured shells folded at one end. The background in three smears showed massive acute inflammation. A scanning electron microscope study of one case revealed that the ova had a relatively smooth surface with an invaginated area at one end.

Adult↗

PubMed1997

[Scanning electron microscopic observation of the three-dimensional structure of laryngeal carcinoma using freeze-cracking method].

OBJECTIVE: To investigate the relation between the morphology and the biological characteristics of laryngeal carcinoma. METHODS: The freeze-cracking method was used to examine 126 specimens of the larynx under scanning electron microscope (SEM). The specimens were obtained from 12 patients suffering from laryngeal cancer and 4 patients with normal larynx. RESULTS: (1) In the normal larynx, the squamous-cell epithelium showed marked keratinization and the intracellular bridges were clear and regular. (2) In areas adjacent to cancer, the structure of the squamous-cell epithlium could be identified, but the cells were deranged and paramorphic. (3) There were two types in the marginal area of the carcinoma. Along the areas adjacent to cancer, infiltrating lymphocytes were usually observed and the surface of the lymphocytes had many leading lamella. CONCLUSION: The results indicate that the three-dimensional observation with SEM using the freeze-cracking technique is helpful for studying the relation between morphology and biologic characteristics of laryngeal carcinoma.

Carcinoma, Squamous Cell↗

PubMed1990

Scanning-electron-microscopic studies on the pathogenesis of exencephaly and cranioschisis induced in the rat after neural tube closure.

Following a single-dose (15 mg/kg) administration of cyclophosphamide on day 12 of gestation to Wistar rats, fetuses were collected at various intervals of time and studied under the scanning electron microscope. Comparisons were made with age-matched controls. Disorganization of the neuro-epithelium (NE) was characterized by expansion of the intercellular space (ICS), appearance of abundant cellular debris, extravascular red blood cells and formation of haemorrhagic cysts in the subependymal zone. Proliferation of the choroid plexus and its surface modifications parallelled the changes in the NE. The ventricular system dilated progressively. Supra-ependymal elements appeared earlier and in greater abundance in the experimental than in the control embryos. The mesenchymal cells of the cyclophosphamide-treated embryos were scanty, poorly organized, had less numerous cytoplasmic processes than the corresponding controls and failed to develop into the primordium of the skull vault. Degenerative changes in the NE, ventricular dilatation and the absence of a supporting skull vault primordium appeared to underlie the reopening of the closed neural tube.

Animals↗

PubMed1978

Scanning electron microscope study on the mechanism of obstructive jaundice in rats.

The possible communication between the bile canaliculus and the space of Disse was examined by experimentally inducing obstructive jaundice in rats. Blood bilirubin levels were measured and the morphological changes in the liver were observed with the scanning electron microscope (SEM); Golgi's silver impregnation was also applied to demonstrate bile canaliculus. The normal bile canaliculus issued side branches but these ended blindly and showed no communication with the space of Disse. The pericapillary space of Disse frequently extended between the liver cells forming a paracapillary space. This space reached close to the bile canaliculus but never connected with it. Seven to 14 days after bile duct ligation, when a maximal level of bilirubin was reached, direct connection of bile canaliculi and pericapillary or paracapillary spaces could be found in many places. Two routes of bile leakage were discerned: One was formed by the side branch of the bile canaliculus directly connected to the pericapillary or paracapillary space, and the other was a communication of the laterally extended bile canaliculus to the paracapillary space, the junctional complex being overrun (Fig. 12).

Animals↗

PubMed2003

[Scanning electron microscope observation of the effect of different dentin bonding surfaces on the bonding interface].

To study the microstructural influence of dry or wet dentin bonding surface on the dentin bonding interface, five wet bonding systems were used to bond Chrisma B20 resin with dry or moist dentin surface with scanning electron microscope. All these systems were found to be well able to infiltrate into the dentin bonding interface on wet dentin surface, and significant changes occurred in the bonding interface when acetone-based adhesives were applied on dry dentin surfaces, demonstrating thinner hybrid layer and the formation of partially hybrid region, while alcohol- and water-based adhesives showed no changes. The necessity of moist dentin surface is therefore suggested when wet bonding systems are used.

Dental Bonding↗

PubMed1986

Revascularisation of free full thickness skin grafts in rabbits: a scanning electron microscope study of microvascular casts.

Casts of the vasculature of free full thickness skin grafts from rabbits' thighs and of the graft beds prepared on their ears, were obtained by microvascular injection of "Mercox", a methacrylate preparation. After transplantation, similar casts were made of the grafted area. All the casts were examined in a scanning electron microscope. Partial filling of the graft vasculature was observed 3 days after grafting and complete filling 5 to 7 days afterwards. These results confirm that vascularisation of free full thickness skin grafts is accomplished through early anastomoses between the original small vessels of the graft and the bed.

Animals↗

PubMed1997

Scanning electron microscopic study of hypoplastic type amelogenesis imperfecta in primary teeth.

Amelogenesis imperfecta (AI) comprises a diverse group of hereditary enamel disorders that are characterized by hypoplastic and in some cases hypomineralized defects. Purpose of this investigation was to characterize the ultrastructure of autosomal recessive smooth hypoplastic amelogenesis imperfecta enamel. The primary teeth that exfoliated physiologically were studied by scanning electron microscopy. By using scanning electron microscope, multiple shallow depressions and deep tubular voids were observed. Irregular enamel, irregularities in enamel crystallites, hypoplastic areas on the enamel surface were seen.

Amelogenesis Imperfecta↗

PubMed1984

Scanning electron microscopic structure of the finger print as related to the dermal surface.

This paper aims to clarify the relationship of the dermis to epidermal ridge configuration. After fixation, human fingertip epidermis was peeled off from the dermis by alkaline treatment, and the dermal surface was observed with the scanning electron microscope (SEM). The SEM pattern of furrows, grooves, and papillae showed an exact negative fingerprint image. Papillae had various sizes and complicated shapes and were arranged continuously but irregularly on each side of the furrow. Size and shape variabilities were not dependent on the site of the fingerprint region. The papilla number tended to increase with age due to derivation of secondary papillae from the primary papilla as well as new formation of small papillae. The dermal surface exhibited some site-specific fibrous appearance at the furrow and papilla, whereas the surface was smooth at the groove. The characteristics of the dermal surface structure as related to the epidermis can be explained by a stronger dermis-epidermis adhesion at the furrow than at the papilla or at the groove.

Dermatoglyphics↗

PubMed1991

Citric acid treatment of periodontitis-affected cementum. A scanning electron microscopic study.

Previous studies have described an inconsistent histological occurrence of a zone of surface demineralization on periodontitis-affected cementum following treatment with citric acid, and a lack of connective tissue attachment to the latter surfaces. In view of these findings, the purpose of the present study was to use scanning electron microscopy to examine the surface morphology of cementum from normal and periodontitis-affected root surfaces following citric acid treatment for differences in the effects of the demineralizing solution on these surfaces. Cementum surfaces were derived from the roots of extracted human teeth from areas beneath attached periodontal ligament fibers (normal) and calculus deposits (periodontitis-affected). 5 specimens were evaluated in both groups. Periodontal ligament fibers were removed from normal root surfaces with a curette, and calculus deposits were removed from periodontitis-affected root surfaces using an ultrasonic scaler. The resultant 5 specimens in each group were then sectioned in half, one-half serving as the untreated control and the other as the experimental, citric acid treated specimen. Experimental specimens were immersed in a saturated solution of citric acid, pH 1 for 3 min and then rinsed in tap water. Both control and experimental specimens were dehydrated in ethanol, critical-point dried, sputter-coated with gold and examined in the scanning electron microscope for morphological characteristics. Citric acid treatment of cementum from normal root surfaces produced an undulating, markedly fibrillar surface morphology which is consistent with the exposure of a fibrillar, collagen substrate. Periodontitis-affected cementum, however, was not appreciably altered in appearance by the citric acid treatment, having only a faint mat-like surface texture. (ABSTRACT TRUNCATED AT 250 WORDS)

Citrates↗

PubMed1989

A scanning electron microscopic study of exfoliated malignant oral epithelial cells.

Investigators disagree regarding the value of exfoliative cytology in the diagnosis of oral cancer. The objective of the present study was to examine exfoliated oral epithelial cells from malignant lesions of the oral mucosa by means of Scanning electron microscope (S. E. M.) in order to determine whether SEM surface characteristics might be useful and specific to predict more accurately the nature of these lesions. Twenty cases of squamous cell carcinomas of non keratinized sites of the oral mucosa (Cheek and floor of the mouth) were selected for this study. Exfoliated cells were collected by scraping by means of modified Ayre's spatula and spread over a standard glass microscope slide for light microscope examination, while those for SEM were spread evenly on a plastic square (1 cm2) cut from a polyester sheet of Melinex "O" (Firket 1966). Altered tissue architectures and cell surface architectures were demonstrated in malignant oral lesions. Bizarre cell forms often showing an absence of close cell-cell contact relationships were seen. The observed cell surface patterns were apparently not related to the degree of keratinization when compared to normal surface patterns of corresponding areas of oral mucosa studied in a previous work. These changes appeared to some extent to be related to the clinical diagnosis and to the degree of epithelial atypia observed by the lesions. In conclusion the observations made in this study demonstrate that surface structural differences exist between exfoliated cells from malignant lesions of the oral mucosa and those from corresponding normal non keratinized sites and that the SEM might be of a diagnostic value.

Carcinoma, Squamous Cell↗

PubMed1991

A scanning electron microscopic study of the human ovarian surface epithelium: characterization of two cell types.

The surface of the ovary has two types of epithelial cells. We have called these A and B cells and they are found in their own respective zones (A and B). To assess the scanning electron microscopic features of these cell types, 65 ovarian samples were collected from biopsies taken from 35 women with normal ovaries. Biopsies included developing follicles, corpora lutea and ovarian capsules. Type A cells were cuboidal and sometimes tall, with a mean diameter of 6.49 microns, and a mean density of microvilli of 6.48/microns 2. Type B cells, on the other hand, were flat squamous cells with broader and flat apices with mean diameters and microvillus density of 11.71 microns and 3.88/microns 2 respectively. The A and B zones were common to all surfaces including the distending follicle. Type A cells overlying the distended surface of a follicle had a mean diameter of 7.03 microns compared to a mean of 6.05 microns for the capsular surface. Type B cell diameters and the microvillus density of both types were more variable and did not differ significantly over any of the surfaces. We suggest that previous human studies which identified flattening of cells over the distending follicle were probably observing B cells. The relationship of the B zones to papillae and surface bridges on the ovarian surface, and the association of these with ovulation sites, suggests that B cells are probably metaplastic cells derived in response to chronic surface injury with ovulation.

Adult↗

PubMed1990

A comparison of the size of fenestrations in the internal elastic lamina of young and old porcine aortas as seen with the scanning electron microscope.

The size of the fenestrations (windows) in the internal elastic lamina (IEL) of arteries may be important in the functioning of the blood vessel wall. The fenestrations are filled with collagen, muscle, and (or) ground substance, which must be removed to make the fenestration visible with the scanning electron microscope. All of the nonelastic components are removed with a hot alkali solution. Our experiments were designed to compare the fenestration size in the IEL of the thoracic aorta of young (6-8 weeks) and old (6-9 months) pigs. A protocol for digestion of young pig tissue was developed and showed that fresh young aortas should be digested in 0.1 M NaOH at 75 degrees C for 2 h and fixed tissue should be digested for 5 h. The average area of the fenestrations for young pig thoracic aortas digested for 2 h was 1.8 +/- 0.29 (SE) microns 2 and for the old pig aortas digested for 2 h was 1.7 +/- 0.11 (SE) microns 2. These values were not significantly different (p greater than 0.05), but the IEL from young pigs appeared rougher than the previously reported smooth IEL of the adult pigs.

Aging↗

PubMed1991

Interstitial cells of Cajal and Auerbach's plexus. A scanning electron microscopical study of guinea-pig small intestine.

Interstitial cells of Cajal (ICC) appear to be involved in the regulation of intestinal motility, probably as pacemaker cells. We investigated the complex organization of ICC associated with Auerbach's plexus of guinea-pig small intestine in the scanning electron microscope. The plexus was exposed by microdissection of zinc iodide/osmic acid stained tissue. After separation of the muscle layers by microdissection alone, the exposed Auerbach's plexus was seen to be covered by a smooth mat of reticular fibrils, thin enough to allow the detailed examination of the intact nerve plexus and interstitial tissue. ICC were distinguished as small, ovoid cell bodies from which 2-5 long, branching, roughly cylindrical processes emerge, associating to form a complex network. Characteristically, ICC processes participated in the formation of small bundles along their course, individual processes passing from one bundle to another. Cell bodies and processes of ICC were intimately associated with tertiary nerves of Auerbach's plexus. Axons were identified and distinguished these from ICC processes by their varicose structure and by th smaller diameters as compared with ICC processes. We found no single axons in our material. The characteristic morphology of ICC clearly distinguished these as a separate cell population different from neurons, glial cells, fibroblasts, and smooth muscle cells. After removal of the mat of reticular fibrils by chemical digestion the detailed organization of the interstitial tissue was preserved. Macrophage-like cells were previously demonstrated by other techniques to constitute a constant and rather dense population of cells in the studied location. As an indication that we preserve the full complement of interstitial cells by our technique, these macrophage-like cells wer for the first time identified in material processed for scanning electron microscopy. The cells had characteristically irregular cell surfaces with short, veil-like, folded extensions intertwined between the other cells in the interstices. Our study establishes an improved correlation between results obtained by the application of scanning electron microscopy to dissected tissue and results from light and transmission electron microscopy of the intact tissue.

Animals↗

PubMed1991

Light and scanning electron microscopic changes observed in experimental arterial forks of rabbits.

Experimental arterial forks were fashioned by anastomosing one common carotid artery to the contralateral vessel by microvascular surgery in rabbits. In one rabbit group the forks were examined histologically by the serial section technique from 5.5 to 25 months postoperatively. The second group was used for scanning electron microscopy of the arterial endothelial surface from 1 to 257 days post-operatively. Intimal proliferation was observed at the lateral angles histologically at sites comparable to those where intimal proliferation occurs spontaneously in human infants. In addition, disruption of the internal elastic lamina with minimal intimal proliferation occurred at the sides of the neo-apex, mostly in the transposed artery. These disruptions corresponded to predominantly transversely orientated tears of the internal elastic lamina from 8 days post-operatively in the scanning electron microscopic study. They were similar to the early atrophic changes preceding berry aneurysm formation in human cerebral arterial forks. The results indicate that both intimal pads (cushions) and elastic tears can be haemodynamically induced.

Anastomosis, Surgical↗

PubMed1989

Scanning electron microscopic study on the lingual papillae of the Japanese insectivora.

The tongue and lingual papillae of the Japanese Insectivora, the Shinto shrew (Sorex caecuiens saevus), the long-clawed shrew (S. unguiculatus), the dsinezumi shrew (Crocidura dsinezumi dsinezumi) and the Japanese water shrew (Chimarrogale himalyica platycephala), were observed by scanning electron microscope. The tongue of these animals had two vallate papillae. In two species of the Sorex a papilla in the vallate papilla was surrounded by two separated trenches, but in the other species it was surrounded by only a continuous trench and a clear vallum. The fungiform papillae in the Sorex were less developed than those of the other species. In the Sorex and Crocidura, there was no filiform papilla on the lingual apex. These genera, however, have papillary projections in the margin of the lingual apex. The results of this investigation suggest that the Sorex and Crocidura indicate an ancient form of the mammalian tongue. These characters, furthermore, were compared among seven species in six genera added three species observed by Kobayashi et al. (1983) to this study.

Animals↗

PubMed1985

Scanning electron microscope study on the biodegradation of IOL and suturing materials.

The biodegradation of the IOLs (27 cases: mainly prepupillary lens with pupillary fixation, irido-capsular and angle supported lens and a J loop lens for posterior chamber lens) and suturing materials of four cases have been studied by Scanning Electron Microscope (SEM). The longest duration in the eye was 7.5 years and the shortest 0.3 year. The materials used for optics were PMMA with the exception of one case of glass. The materials for haptics were Nylon 6, Isot.PP, PMMA, PVDF, Polyimid and Pt-Ir. The suturing materials were Nylon 6 and Isot.PP. Nylon 6 degraded in the eye and Isot.PP degraded in the corneal tissue. But no biodegradation was observed in Isot.PP, PMMA, PVDF and Pt-Ir in the eye. In our investigations, biodegradation has some relationship to age (over 50 years old), duration (within 7.5 years) and inflammation of the eye, but ultimately biodegradation will depend on the individual situation. Degradation occurs most easily in the curved portion of Nylon 6.

Age Factors↗