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Results for “scanning electron microscope”

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PubMed1977

Black hairy tongue. A scanning electron microscopic study.

A patient with tongue malignancy associated with a black hairy tongue is presented. Specimens from e area fo the black hairy tongue and from a normally appearing part were studied with the scanning electron microscope. The "hairs" consisted of elongated filiform papillae due to accumulated keratinized layers. In-between these layers, fungi and bacteria were found. The aetiology of the blck hairy tongue in this patient is discussed.

Humans↗

PubMed1990

[The development of the tongue in the chick embryo: observation under a scanning electron microscope].

The morphological features of the chick embryo tongue from the 8th day of incubation till hatching and during the early post incubation period have been investigated by means of Scanning Electron Microscope. At the SEM, it is possible to observe that already at the 8th day of incubation, the body and the root are separated by a low smooth-surfaced ridge. In the following days this ridge develops, giving rise to the so-called lingual spines, whose significance is still uncertain. As concerns the evolutive pattern of the superficial layer of the epithelium, in the first days of the considered incubation period the cells appear dome-shaped and have microvilli on their apical surface; afterwards they tend to become more flattened, and the microvilli are replaced by a thick net of microplicae. In the last days of incubation and after hatching desquamative phenomena become evident. The above described evolutive process can be regarded as a common feature of the whole dorsal lingual surface; only few regional differences are to be noted, such as the earlier development of the microplicae on the apex and borders of the tongue. In particular, the microplicae observed at the apex of the tongue show a typical aspect and arrangement; they run regularly parallel to each other. On the lingual dorsal surface taste bud-like structures have never been observed.

Animals↗

PubMed1994

The vascularization of the pituitary gland of the chicken (Gallus domesticus). A scanning electron microscope study of vascular corrosion casts.

Microvascular corrosion casts of the pituitary gland of one to nine-day-old chickens (Gallus domesticus, white leghorn hybrids) were analysed with the scanning electron microscope. Results show that the chicken median eminence is supplied by branches of the infundibular and the neural-lobe arteries. They form a flat two-dimensional primary capillary plexus, which lacks any capillary loops and is continuous with the plexus in the neural lobe. The capillaries occupy about 60% of the total area of the median eminence. A subependymal plexus is present, showing no contact with the plexus of the median eminence. The chicken neural lobe consists of many hollow buds. These buds are supplied by branches of the neural-lobe artery, which gives rise to a two-dimensional capillary meshwork similar to that of the median eminence. An anterior group of portal vessels, comprising 14-16 vessels with a mean diameter of 37 microns, and a posterior group of portal vessels, comprising 2-4 shorter and slightly thinner vessels, arise from the median eminence are the sole blood supply for the adenohypophysis (distal lobe). Anterior portal vessels supply the cephalic lobe and the most rostral area of the caudal lobe, and posterior portal vessels supply the caudal lobe of the distal lobe. There are no short portal vessels connecting the neural lobe with the distal lobe. The (sinusoidal) capillary bed of the distal lobe is laminated. The chicken hypophysis drains into the cavernous sinus, which empties into the cerebral carotid veins. Within the period studied (days 1-9 after hatching) no age-related changes were found.

Animals↗

PubMed1976

Scanning electron microscopic study of the effects of pressure on the luminal surface of the rabbit aorta.

The effects of pressure on the luminal surface of the rabbit aorta were investigated using the scanning electron microscope. The method followed was perfusion under hydrostatic pressure of a section of thoracic aorta, in vitro. The characteristic ridged pattern seen in sections fixed at zero hydrostatic pressure was to a large extent eliminated when fixation occurred at pressures equivalent to those experienced by the aorta at systole or diastole. This study suggests that the spiral ridged pattern is dependent upon the fixation pressure and may not be present in a normally functioning artery. Any attempts to characterize or interpret the appearance of the luminal arterial wall must take into account the effects of pressure.

Animals↗

PubMed1991

Scanning electron microscopic features of Kaposi's sarcoma.

In order to clarify the three-dimensional structure of Kaposi's sarcoma (KS) five cases of KS of the skin were observed with a scanning electron microscope (SEM). KS lesions were investigated both in vascular and spindle cell areas and were compared with similar areas observed by light microscopy. KS appears as a spongelike neoplasm consisting of irregular vascular channels lacking endothelial cells and well-developed basement membranes. Vascular spaces and vascular slits are packed with numerous red blood cells (RBCs). SEM features of KS share some similarities with those of hemangiopericytoma, a vascular tumor composed of mature endothelial cells surrounded by pericytes. These findings are consistent with the hypothesis according to which the proliferating cells of KS are viewed as immature endothelial cells with partial differentiation into pericytes.

Cell Division↗

PubMed1976

Scanning electron microscopic observation on intracellular structures of ion-etched materials.

Ion-etching technique on the cracked surface of biological material may give a plastic visualization of intracellular structures under the scanning electron microscope, because membraneous structures in the cell are generally etch-resistant and the cytoplasmic matrix is easily ion-etched. Mild ion-etching using low voltage was applied to the cells of the pancreas. Nuclear pores were clearly disclosed but were enlarged slightly in the process of etching. Endoplasmic reticulum with ribosomes, Golgi apparatus, mitochondria, some filamentous structures and crystalline inclusions (B cell granules) were also effectively disclosed by ion-etching technique. It is necessary, however, to compare the etched specimens carefully with non-etched ones to determine whether given structures observed are intrinsic ones or artifacts caused by etching.

Animals↗

PubMed1998

Scanning electron microscopic study of the renal glomerulus by an in vivo cryotechnique combined with freeze-substitution.

The 3-dimensional ultrastructure of mouse renal glomeruli under normal haemodynamic conditions was studied by scanning electron microscopy using an in vivo cryotechnique followed by freeze-substitution, and compared with glomeruli prepared by conventional fixation methods. Mouse kidneys were frozen with a cryoknife apparatus and a liquid isopentane-propane mixture (-193 degrees C). Surface areas of the frozen tissues were freeze-fractured with a scalpel in liquid nitrogen. The specimens were routinely freeze-substituted, freeze-dried, ion-sputtered, and then observed in a scanning electron microscope at an accelerating voltage of 5 kV. Renal glomeruli showed good ultrastructural preservation of the surface tissues. Podocytes with interdigitating foot processes covering capillary loops exhibited smooth surface contours and their cell surfaces were arranged more tightly than those seen by the conventional fixation method. Filtration slits between foot processes were found to be narrow. The internal structure of the glomerular tuft was seen in the freeze-fracture faces. The capillary lumen with variously shaped erythrocytes was kept open in frozen glomeruli under normal blood circulation conditions. The ultrastructure of renal glomeruli, as revealed by the in vivo cryotechnique with freeze-substitution, appears to be closer to that of the living state.

Animals↗

PubMed1984

A scanning electron microscopic study of dentin dysplasia type II in primary dentition.

Dentin dysplasia type II is a rare autosomal dominant defect which affects dentin formation in both the deciduous and the permanent dentitions. The scanning electron microscopic study performed on a primary central incisor presents some findings similar to those reported in dentinogenesis imperfecta. Because of the lack of published reports on dentin dysplasia type II, it is difficult to ascertain definitive characteristics of this dentin abnormality.

Child, Preschool↗

PubMed1979

Utilization of cadaver tissue for a scanning electron microscopic study of the insertion of the masseter muscle.

1. The generally poor state of soft tissue preservation that complicates observations by gross dissection and light microscopy posed no hindrance to scanning electron microscopic (SEM) studies of bone surface, because all of the soft tissues are chemically removed. 2. Specific and identifiable surface patterns representing locations of periosteal and fibrous muscle attachments can be readily observed in cadaver tissue with the SEM. 3. SEM observations confirmed earlier literature concerning the extent of periosteal and intraosseus attachments of the masseter muscle. The masseter muscle attached periosteally on the lateral surface of the mandible and along the inferior border. Just above the inferior border, a ridge of intraosseous attachment was noted. 4. The correlation of SEM observation of bone surface patterns with gross dissection and light microscopy demonstrated that SEM can be useful in determining the extent of muscle attachments in cadaver tissue even when the soft tissue is poorly preserved.

Adult↗

PubMed1990

The development of the chick embryo gallbladder studied by scanning electron microscope.

The differentiation of the gallbladder mucous membrane in chick embryos has been studied from the 11th day of incubation until hatching (stages 37-46 of Hamburger an Hamilton 1951) with scanning electron microscope. The surface of the mucous membrane, at the 11th day of incubation, appears regularly smooth. From the 12th day onwards, longitudinal folds appear on the surface of the mucous membrane, becoming more and more numerous and complicated in the following days. During the last days of incubation, branching and anastomosing folds are present. At the 11th day of incubation, the epithelial cells lining the gallbladder surface have flattened apices, with short microvilli. From the 12th day onwards, the epithelial cells show dome shaped apices, with long numerous microvilli. From the 15th day of incubation onwards, some particular secretory cells can be detected. The appearance of these cells is probably related to the water-absorbing function of the gallbladder which in the last days of incubation completes its functional development, because of precise digestive requirements of the chick embryo.

Animals↗

PubMed1976

Human stapes crura: surface bone architecture: scanning electron microscopic findings.

Human stapes crura obtained at the time of stapedectomy for clinical otosclerosis have been studied after removal of the mucosal and periosteal layers by treatment with hydrogen peroxide and ultrasonification. With the scanning electron microscope, four basic architectural patterns are evident: honeycomb, fibrillar, compact and pitted. The significance of these patterns is as yet unclear, but they do appear to be in intimate relationship one to another and perhaps are varying stages in a single process.

Ear Ossicles↗

PubMed1982

A new method of magnifying photographic images using the scanning electron microscope in the backscattered electron detection mode.

This paper describes a new method of magnifying small images in photographic film by means of a scanning electron microscope (SEM) operated in the backscattered electron detection mode. The study included tests of several types of radiographic film, transmission electron microscopy film, and black and white 35 mm film. The electron optical enlargement method is particularly useful in situations where the film sample is opaque to light and for generating enlarged images at magnifications beyond the reach of light optical enlargement methods, i.e. up to approximately 2000X with ease and rapidity in a single step. The electron optical enlargements compare favorably in contrast and detail with the enlargements made with a light microscope and with a darkroom enlarger.

Breast Diseases↗

PubMed1976

Scanning electron microscopic and electrophoretic studies on clotting factor adsorbents.

Physical studies carried out on a range of protein and clotting factor adsorbents revealed marked morphological and charge differences. Their appearance in the scanning electron microscope could be used to classify the insoluble precipitates, calcijm phosphate, barium sulphate and citrate, as either amorphorous or crystalline. Surface charge is difficult to define but the present studies on the sparingly-soluble salts, based on calcium and barium, have revealed that they can be subdivided on the basis of the presence or absence of a charge reversal point in the pH-mobility curve. The anion component appeared to determine this characteristic; it was noted that phosphate and citrate ions had a marked effect and gave a biased negative potential at all pH values. We concluded that where a divalent cation is cohabiting with a trivalent anion, the greater potential-determining ability of the latter will dominate the overall charge at the surface of a particle, even below pH7 and the absence of a positive potential gives a monophasic pH-mobility curve. Differences in both the physical appearance and electrophoretic mobility of the adsorbents studied reflect the wide variation in their chemical composition, especially among the various forms of calcium phosphate which, unlike barium sulphate, can include substituted ions such as hydroxyl, in their crystal lattice. The definition of these characteristics allows their behaviour towards clotting factors to be more easily predicted.

Adsorption↗

PubMed1978

Scanning electron microscope studies of the egg shell in some anostraca (Crustacea: Branchiopoda).

The tertiary shell of the eggs of anostracan crustaceans consists of two layers, an outer cortex and an inner alveolar layer. Scanning electron microscope studies show that, in most species, these layers are separated by a subcortical space which intercommunicates with spaces in the cortex and with the meshwork of the alveolar layer. No evidence was found for direct communication between pores on the surface of Branchipus stagnalis eggs and the subcortical space. No surface pores were found in the eggs of Branchinecta packardi, Chirocephalus diaphanus, Artemia salina, nor in eggs of the notostracan Triops cancriformis. Similarities in structure and possible functions of the egg shells of anostracan crustaceans and certain insects are discussed in relation to similarities in certain features of their environments.

Animals↗

PubMed1990

Three-dimensional structure of intracellular membranous organelles in embryonic chick skeletal muscle cells in vitro revealed with scanning electron microscope.

Using the freeze-polishing and osmium-maceration procedures, the ultrastructure of intracellular membranous organelles in embryonic chick skeletal muscle cells in vitro was investigated three-dimensionally with the scanning electron microscope (SEM). T-system tubules followed a tortuous course and possessed many warts. Some of these tubules could be traced to the sarcolemma. The sarcoplasmic reticulum (SR) had elaborate structures of a hexagonal pattern. By comparing the SEM images with those of ultrathin sections of myotubes impregnated with ferritin particles, the distinction between the T-system and SR was confirmed. Late in the culture, these two intracellular membranous systems were arranged periodically at right angles to the longitudinal axis of the myotubes. Round-shaped mitochondria were often arranged in chains connected with slender rods. Long rod-shaped mitochondria exhibited occasional branchings.

Animals↗

PubMedDate not supplied

The trajectories of secondary electrons in the scanning electron microscope.

Three-dimensional simulations of the trajectories of secondary electrons (SE) in the scanning electron microscope have been performed for plenty of real configurations of the specimen chamber, including all its basic components. The primary purpose was to evaluate the collection efficiency of the Everhart-Thornley detector of SE and to reveal fundamental rules for tailoring the set-ups in which efficient signal acquisition can be expected. Intuitive realizations about the easiness of attracting the SEs towards the biased front grid of the detector have shown themselves likely as false, and all grounded objects in the chamber have been proven to influence the spatial distribution of the signal-extracting field. The role of the magnetic field penetrating from inside the objective lens is shown to play an ambiguous role regarding possible support for the signal collection.

Journal Article↗

PubMed1991

Gold-associated lymphadenopathy in a patient with rheumatoid arthritis. Histologic and scanning electron microscopic features.

The histologic features of adenopathy associated with intramuscular injections of gold sodium thiomalate in a woman with rheumatoid arthritis are presented. We believe that the light microscopic features of the above process are sufficiently distinctive that a diagnosis of gold-associated lymphadenopathy could be rendered. A review of the literature revealed no descriptions of the light microscopic appearance of gold in lymph nodes. In this case, the diagnosis of gold-associated lymphadenopathy was confirmed by scanning electron microscopic studies.

Arthritis, Rheumatoid↗

PubMed1988

Scanning electron microscopic study of dentin walls of the pulp chamber by a replica technique.

Precise replicas of the pulp chamber were made with a low-viscosity synthetic resin and examined with a scanning electron microscope. As a result, it was confirmed that the pulp horns and the pulp roof were clearly observed at both low and high magnification by this replica technique. Furthermore, interesting findings were made. That is, a vessel-like linear ridge or groove, measuring 5 micron in diameter, was observed on the surface of the replica. The ridge or groove ran across the top of the pulp horn to the pulp roof in the direction of the other horns. Such a linear ridge or groove was found in 32 of 50 specimens (64%). It may be interpreted that there was a stringy structure embedded in the calcospherites beneath the predentin. However, the origin of these structures could not be determined in this experiment.

Dental Pulp↗