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 685 records · Page 38Linked to original sources
PubMed1989

Dental elements in mature teratomas of the ovary: scanning electron microscope ultrastructure.

Seventy-two teeth from 10 ovarian mature teratomas and 12 unerupted and erupted teeth from subjects aged 8 to 21 years were examined at the scanning electron microscope to evaluate the morphologic and histogenetic differences. The ultrastructure of the teratomatous teeth was similar to that of the corresponding orthotopic tissues. Despite this similarity the morphology of the teratomatous teeth was much less well defined, attesting to the inductive effect of the contiguous tissues that are normally present in the oral cavity.

Adolescent↗
PubMed1984

Scanning electron microscopic and X-ray microdiffractometeric studies on sialolith-crystals in human submandibular glands.

The crystalline structures of 18 submandibular gland calculi were studied by radiomicrography , scanning electron microscope, and X-ray microdiffractometeric techniques. The following observations were made by SEM: Granular or globular structure was seen on the surface of all cases and pyramidal crystal in one case. In the inside, all showed lamellar pattern with amorphous nucleus in the center, and granular, plate-like and rhombohedral structures were also observed. X-ray microdiffractometeric analyses: Apatite was frequently observed in both outside and inside of the calculi. Whitlockite was next frequently detected and was seen more often in the inside. Brushite and weddellite were noted in the outside of calculi in one case each. Thus, it is suggested that brushite and weddellite were present in the front portion of calculus formation and then transformed into the more stable form e.g. apatite.

Apatites↗
PubMed1977

The effect of an expectorant on the tracheal mucosa. A scanning-electron microscopic study.

The effect of an intravenous expectorant agent, i.e. Bisolvon, on the secretory activity of the tracheal mucosa of the dog was studied with the scanning electron microscope. A marked increase in the production of tracheal secretion was observed 15 and 30 min following the injection. Both the goblet cells in the epithelium and the seromucinous glands in the tunica propria contributed to the formation of the secretion. 60 min after the injection, the submucosal glands were shrunken or empty. The rapid secretory response to the expectorant, Bisolvon, confirmed the active and important role of the tracheal mucociliary clearance mechanism for the protection of the lower respiratory tract.

Animals↗
PubMed1987

The effects of differing etch times on the etch pattern on enamel of unerupted and erupted human teeth examined using the scanning electron microscope.

The etch pattern produced on enamel from unerupted and erupted human teeth with varying periods of acid etching using 37 per cent phosphoric acid was examined using a scanning electron microscope. For erupted enamel etch scores were fairly consistent above 10 seconds etching, for unerupted enamel etch scores matched those for erupted enamel for etch times above 30 seconds. The etch type was more consistent on unerupted enamel.

Acid Etching, Dental↗
PubMed1977

A scanning electron microscopic study of the relationship between the most apically located subgingival plaque and the epithelial attachment.

Twelve teeth with chronic periodontitis were extracted and examined in the scanning electron microscope. Subgingival plaque in deep pockets was usually covered by a surface coating, which was absent in the apical part. The apical plaque displayed an organized structure, although varying form one tooth to another. The microorganisms were sometimes overlapping the epithelial cell remnants. Coccal forms were seldom found, but on a morphologic basis, rod-like, filamentous, spiral and branching forms were identified. Both bacteria and spirochetes seemed to have the capacity to invade the epithelial remnants on the tooth surface. The epithelium in direct contact with the microorganimsm showed a widening of the intercellular spaces and a change in surface morphology. This was in contrast to cell layers more distant from the plaque, which appeared normal and homogeneous. Similar reactions were also seen in gingival epithelial-like cell cultures infected with plaque of human origin.

Bacteria↗
PubMed1979

Scanning electron microscope studies of the endometrium of the cyclic mare.

Endometrial biopsies obtained from mares at different stages of the oestrous cycle, during anoestrus and in various abnormal conditions were examined with the scanning electron microscope. Preliminary observations suggest that the patterns of secretory and ciliary activity in the uterine epithelium are similar to those observed by electron microscopical techniques in laboratory and other large domestic animals. The response of the epithelial cells to hormonal variations and infections is compared with that of the endometrium as seen with the light microscope.

Anestrus↗
PubMed1978

The outer segments of photoreceptive pinealocytes in the pineal organ of the funa, Carassius gibelio langsdorfi. A scanning electron microscopic study.

The form and size of the outer segments of photoreceptive pinealocytes in the pineal organ of the funa, Carassius gibelio langsdorfi, were observed with the scanning electron microscope. The height of the outer segments measures between 1 and 3 micrometer and the diameter varies widely from 1.5 to 8 micrometer. Various forms of outer segments, i.e. a slender type, a dome-like type, a cap-like type and a helical type, were demonstrated. The parallel-oriented filamentous processes of the inner segments have the same length as the outer segments and a diameter of approximately 100 nm; they are projections from the apical border of the inner segment and surround the cone-like outer segments. The processes make a right angle with the lamellar disks. The distance between two processes averages 100 nm. The lamellar disks of the outer segments are oriented at right angles to the modified cilium in the basal part, but the angle often changes in the peripheral part, where the lamellar disks are raised and become parallel to the cilium.

Animals↗
PubMed1975

Effects of highly dosed ultrasound on the growing rabbit's larynx. Scanning electron microscopic and reflecting ligth microscopic findings.

The morphologically recognizable effects of highly dosed ultrasound application on the growing rabbit's larynx (5 Watt/cm2 for 10 min) were studied by means of scanning electron microscopic (SEM) and reflecting light microscopic (RLM) methods. It could be shown that the area of cartilaginous necrosis corresponded exactly to the location of ultrasound application and was sharply limited by the normal cartilage. After a survival period of six weeks, areas of chondroneogenesis became visible on the endolaryngeal perichondrium. After a survival period of twelve weeks, an outer zone of cartilaginous necrosis was still to be seen. Connective tissue directly affected by ultrasound and the endolaryngeal muscles did not show any retarded damage. The results of our experiments permit to state that highly dose ultrasound application on the cartilaginous framework leads to a growth retardation with a subsequent alteration in form and shape.

Animals↗
PubMed1988

The blood vascular architecture of the rat pineal gland: a scanning electron microscopic study of corrosion casts.

The blood vascular bed of the rat pineal gland was reproduced through a low viscosity methacrylate casting medium and observed with a scanning electron microscope. The pineal gland was located in front of the confluens sinuum which was formed by the confluence of the left and right transverse sinuses and the superior sagittal and great cerebral veins. The pineal gland was found to contain a rich vascular network of freely anastomosing capillaries. This network received a few afferent arteries from the posterior cerebral arteries while emitting ten to fifteen efferent veins. Most of these efferent veins drained into the upper segment of the great cerebral vein; the remaining one or two efferent veins continued directly into the confluens sinuum. A marked constriction, probably representing a venous valve or valve-like projection, was observed in the opening area of the great cerebral vein. Circular constrictions, probably representing sphincters, were imprinted in the efferent vessels. No direct vascular connection was noted between the pineal gland and the nervous tissues or between the pineal gland and the choroid plexuses of the third and lateral ventricles.

Animals↗
PubMed1994

High-resolution scanning electron microscopic study of cell organelles of the chick's vestibular ganglion.

The fine intracellular structures of the chick's vestibular ganglion were studied three-dimensionally using the scanning electron microscope (SEM) after freeze-fracturing with 50% dimethyl sulfoxide solution and placement in 0.1% osmium oxide solution. Three patterns of perikaryal myelination could be distinguished in the vestibular ganglion cells: heavily myelinated, lightly myelinated and unmyelinated. Intracellular organelles such as the Golgi apparatus, endoplasmic reticulum and mitochondria could be demonstrated clearly. The stereoscopic structures of the Schwann cells and nerve fibers were also clearly demonstrated.

Animals↗
PubMed2001

Use of oolong tea extract staining of soft-tissue specimens in low-vacuum scanning electron microscope with a cooling stage.

For direct observation of the surface structures of soft-tissue specimens, we examined rat tracheal tissue in a low-vacuum scanning electron microscope (SEM) equipped with a cooling stage. In specimens fixed with glutaraldehyde and osmium tetroxide, back-scattered electron images of the surface structure could not be clearly observed in the low-vacuum SEM because of the disruption of fine structures and a low signal-to-noise (S/N) ratio. Processing of the specimens in 70% ethanol resulted in marked shrinkage, in contrast to results when processing in 30% ethanol. To overcome these problems, the trachea was initially fixed in 2.5% glutaraldehyde (0.1 M phosphate buffer pH 7.4), treated with a mixture of 0.2% oolong tea extract (OTE) and 2.5% glutaraldehyde, and postfixed in 1% osmium tetroxide. The sample was immersed in 30% ethanol and examined in a chilled SEM at -10 degrees C. The luminal coutour of the tracheal epithelial cells was clearly observed because of the decrease in shrinkage. Cilia of ciliated cells and microvilli of nonciliated cells were also clearly observed. These specimens also showed a high S/N ratio, thus allowing the observation of samples without the need for complete dehydration, critical-point drying, or metal coating. This OTE-incorporated conductive staining method is simple and rapid, and should prove to be highly useful for rapid SEM analyses of biological specimens.

Animals↗
PubMed1998

[Morphologic changes of red blood cells in various conditions under scanning electron microscope].

To study the changes of RBC in various conditions, blood clots elapsed 6 days in water and air and bloodstains stored in variant time were observed under Scanning Electron Microscope (SEM). The results showed that the morphology of RBC elapsed 6 days in water and air seemed to retain their integrity. They were measured 5, 48-5, 88 microns in diameter, whereas the RBC in the bloodstains stored 14 years were obviously disfigured and some appeared membrane cracking. However, the structure of RBC membrane was well recognized under the SEM. The morphological changes under the SEM and the forensic significance of the RBC were discussed.

Blood Stains↗
PubMed1989

The blood vascular architecture of the rat thyroid gland: a scanning electron microscope study of corrosion casts.

The blood vascular bed of the rat thyroid gland was reproduced by injection of a methacrylate casting medium and observed with a scanning electron microscope. The rat thyroid gland received the superior and inferior thyroid arteries and emitted the superior and inferior thyroid veins. Anastomosis between the interlobular arteries or between the interlobular veins was frequently observed in the thyroid gland. The arteriovenous anastomosis was rarely observed between the terminal branches of the lobular arteries and veins. The thyroid blood vascular bed was divided into lobular units which consisted of basket-like capillary networks surrounding the thyroid follicles; a small lobular unit consisted of a few networks, whereas a large one of fifty or more networks. Sizes and forms of the networks varied widely in each case. However, the networks in the superficial layers of the lateral parts of the thyroid gland were typically most developed. Regardless of its size and form, each network always received a proper efferent vessel continuous with the lobular vein, though it was sometimes provided with an accessory afferent or efferent vessel. Only occasionally were the adjacent networks fused with each other or connected by transfollicular capillaries. Thus, the present data suggest that each follicular capillary network is a fairly independent functional-unit in the thyroid microcirculation. The capillaries of the network were sinusoidal in nature and sometimes protruded fine projections which indicated the neogenesis of capillaries. The blood vascular bed of the newborn rat thyroid gland was not always differentiated into basket-like capillary networks.

Animals↗
PubMed1978

Observations of ridge appearances in a normal population and in Down syndrome patients (21-trisomy) using the scanning electron microscope.

A celluloid plate containing a drop of amyl acetate was pressed to the skin. The impression thus obtained was coated with carbon and gold and observed under the scanning electron microscope. Impressions from the fingers of the normal population showed the crests and furrows of the finger prints clearly. The impressions from the fingers of Down syndrome patients were a mixture of the normal crests and furrows and of hypoplastic crests and furrows.

Adolescent↗
PubMed1976

Scanning electron microscopic studies on the development of the chick retina.

Fixed retinae of chick embryos and chicks of the first week after hatching were fractured and examined with the scanning electron microscope. The matrix cells of the retina proliferate up to the beginning of the second week. The migrating cells are oriented in cell cords. This columnar organizaion prevails up to the development of the plexiform layers formed as a consequence of the outgrowth of the dendritic and axonal cell processes. Special attention was paid to the differentiation of the ganglion, bipolar and receptor cells, and the radial fibers (Müller cells). Two main morphological patterns are significant for the organization of the retina during neurogenesis: a)the cell to cell contacts of migrating cells and b)the spatial arrangement of Müller cells which could provide guidelines for migration of neuronal elements.

Animals↗
PubMed1992

Scanning electron microscopic study of denervated and reinnervated intrafusal muscle fibers in rats.

Isolated muscle spindles from lower lumbrical muscles of rats were used to study the 3-dimensional organization of intrafusal structures by scanning electron microscopy following (a) complete denervation, (b) reinnervation after a single crush lesion of the sciatic nerve, or (c) reinnervation after transection and immediate suture of this nerve. One week after complete denervation, previous sites of intrafusal motor endplates were transformed into sarcolemmal ovoid bulges. These bulges persisted in denervated muscle spindles up to 12 weeks. Regenerated motor nerve endings were detected on intrafusal muscle fibers 1 month, and thereafter following sciatic nerve crush injuries, and 3 months and later following transection and suture of the nerve. Furthermore, 3 different types of subsynaptic areas of motor nerve terminals were observed. The scanning electron microscopic technique also allowed visualization of splitting and fusion of intrafusal muscle fibers. The findings are discussed in view of their possible functional implications.

Animals↗