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Results for “scanning electron microscope”

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PubMed1993

[The glandular compartments of the canine placenta--a scanning electron microscopic study].

The glandular chambers in the spongy zone grow out of the superficial endometrial glands during the implantation of the embryo. To our knowledge, no scanning electron microscopic investigations of the spongy layer in the placenta of the bitch have been published so far. We examined the placenta at the 44. day of pregnancy by scanning electron microscopy. The glandular epithelium in the spongy zone forms extensive folds, which fill up most of the lumen of the glandular chambers. They are lined by a simple columnar epithelium with high apical protrusions. The luminal surface of the cells is bordered by short microvilli. Numerous vesicles are stacked in the cytoplasm. The tips of the chorionic tufts project into the lumen of the glandular chambers. The lumen is filled with masses of mucus separating the trophoblast from the glandular epithelium. With respect to its morphology, the trophoblast lining the tips of the chorionic tufts is very different from the trophoblast in the other parts of the placenta. The cells are swollen and club-shaped. The cytoplasm is completely supplanted by big vacuoles. We feel that the trophoblast in the glandular chambers is unable to perform any resorptive activity. The significance of the mucus in the glandular chambers in stopping the invasive growth of the trophoblast is discussed.

Animals↗

PubMed1979

Evaluation of the transplacental toxicity of diethylstilbestrol with the scanning electron microscope.

Exposure in utero to the synthetic estrogen diethylstilbestrol (DES) is associated with reproductive tract lesions in male and female CD-1 mice. The scanning electron microscope was used to evaluate the luminal surface of the vagina, cervix, and uterus following prenatal exposure to DES. Abnormalities that have been observed include urethral openings in the cervicovaginal area, squamous metaplasia of the uterus, glandular elements in the vagina, and abnormal cell surface features in the vaginal epithelium.

Animals↗

PubMed1988

Scanning electron microscopic investigations of the human umbilical artery intima. A new conception on postnatal arterial closure mechanism.

Umbilical cord arteries were investigated using a scanning electron microscope using different methods of preparation: Perfusion of one artery under pressure from a 100 cm water column caused artefacts and the preparatory work took at least 10 min after delivery. To shorten this time fully patent umbilical cords were double clamped and fixed immediately after birth. However, the removal of blood after fixation caused the endothelial layer to be lost. Therefore umbilical cords were double clamped, snap frozen and stored in liquid nitrogen until preparation. The endothelial lining of the fully patent umbilical artery at birth is composed of longitudinally arranged, spindle-shaped cells, connected by cellular junctions. The basement membrane contains numerous gaps. Because of these gaps postnatal vasoconstriction causes herniation of the subendothelial myofibroblasts forming subendothelial vacuoles. The vacuoles produce displacement of the endothelial cell cytoplasm towards the vascular lumina resulting in protuberances and blebs on the endothelial cells. Rupture of vacuoles leads to crater-like injuries. Beneath the basement membrane a thin layer of myofibroblasts is arranged longitudinally. Oblique or transversely ordered bundles of myofibroblasts are interposed at wide and irregular intervals. These transverse bundles are able to trigger localized contraction rings called "folds of Hoboken", the initial stage of postnatal arterial closure.

Basement Membrane↗

PubMed1980

Scanning electron microscopic and radiographic correlation of articular surface and supporting bone of the mandibular condyle.

Specimens of mandibular condyle from human cadavers were employed for scanning electron microscopic and radiographic observations of the articulating surface and underlying bone. Smooth articular surface supported by smooth bone was most frequently observed. Craters and depressions in the articular surface were associated with resorption of underlying bone. Lateral radiographs proved to be of limited value in detecting defects of this type.

Adult↗

PubMed1989

The effect of gentamicin on the glycocalyx and the ciliary interconnections in vestibular sensory cells: a high resolution scanning electron microscopic investigation.

Changes in glycocalyx structure and ciliary interconnections of the vestibular sensory cells are demonstrated after gentamicin administration. A special high resolution scanning electron microscope and a tannic acid-osmium staining technique giving an almost three dimensional view were used to achieve this purpose. Guinea pigs were injected with a single dose of 5 mg of gentamicin directly into the middle ear. Seven days after the injection, it was possible to observe the degenerative process of the glycocalyx and the ciliary interconnections. The first detectable change was a disarrangement of the cilia with a loosening of the interconnections. The ciliary membrane presented with an irregular appearance. The tip links connecting the tips of the stereocilia to their neighbours were also affected showing elongation or even disappearance. In the later stages of the degeneration process, the sensory hairs presented with different degrees of fusion whereafter they finally disappeared totally. These findings suggest that the glycocalyx acts to maintain a normal stability and shape of the ciliary membrane and to keep the regular distance between cilia in order to maintain the arrangement of the whole ciliary bundle. Gentamicin probably affects the glycocalyx and the ciliary interconnections resulting in a disarrangement, detachment and fusion of cilia. The tip links, which are suggested to be involved in sensory cell transduction, seem to be also affected by gentamicin.

Animals↗

PubMed1993

Scanning electron microscopic observations of early plaque formation in vivo on enamel specimens treated with delmopinol.

The aim of this double blind, cross-over, scanning electron microscopic (SEM) study was to compare the effect of topical application of 0.5% delmopinol HCl (aqueous solution) with placebo on early supragingival plaque formation on enamel specimens attached to a maxillary premolar. 3 subjects underwent 2x (placebo and delmopinol treatment, respectively) 7 treatment periods (1/2, 1, 2, 8, 24 hours; 3, 7 days) of undisturbed dental plaque accumulation, during which 2 ml of placebo and delmopinol HCl 0.5%, respectively, were applied topically to all teeth 2x daily. At the end of each period, the specimen was retrieved and processed for SEM. For the specimens obtained after 24 h or less, the number of visible micro-organisms was estimated. For the 3- and 7-day specimens, the area covered by plaque was calculated planimetrically. Large inter-individual differences were observed in the number of bacteria attaching during the first 24 h, with apparently no major differences between delmopinol and placebo. 1 subject showed a bacterial colonization predominated by curved rods throughout the first 8 h. Compared to placebo, the area of the specimens covered by plaque was reduced after 3 and 7 days of delmopinol use, with coccoid cells as the predominant morphotype. Plaque maturity, characterized by the appearance of corncob formations and high numbers of different morphotypes, was not observed on the delmopinol specimens, in contrast to the placebo specimens. The study shows that topical application of 0.5% delmopinol HCl delays and interferes with dental plaque maturation.

Adult↗

PubMed1983

Transalveolar fibers of the mouse periodontium: a scanning electron microscopic study.

Transalveolar fibers have been described by many authors using techniques of light microscopy. However, a study of these fibers using techniques of scanning electron microscopy has not been reported. In the present study, scanning electron microscopic techniques revealed that transalveolar fibers were composed of a bundle of smaller fibers. This fiber bundle passed through channels in bone and was attached to the bone by anchoring fibers. Transalveolar fibers branched within bone. Near points of branching, channels were often dilated. Channels were continuous with the connective tissue space of the periodontal ligament at the bone margin. The results presented herein suggested a revised concept for the anchorage of fibers of the periodontal ligament to bone.

Animals↗

PubMed1975

Adaptation of silicate and Adaptic to the margins of cavities. A scanning electron microscope study.

The effects of etching of the enamel, on the adaptation of silicate and Adaptic to the cavity walls was examined with the scanning electron microscope. Replica methods were utilized to ensure that no shrinkage of the filling materials was caused by the vacuum in the instrument. It was shown that following etching of the cavity margins, Adaptic adhered to the enamel with absent, or minimal, fissure formation on one side of the filling, and some on the opposite side. The adaptation of silicate to the margins of the cavities was not improved by etching.

Composite Resins↗

PubMed1975

[Scanning electrone microscopic investigations of synthetic suture material (author's transl)].

Alterations of polyamide 6/6 sewing material after ophthalmologic micro-surgical operations were investigated by a scanning electrone microscope. On the basis of the typical transverse fissures of the nylon strings we succeeded in proving that these alterations were similar to those of a stick with circular cross-section after stress deflexion. Thus the fissures of the string cover can be reduced mainly to a mechanical permanent stress.

Microscopy, Electron, Scanning↗

PubMed1998

Real-time Observation of Aluminum Chemical Vapor Deposition in an Environmental Scanning Electron Microscope.

: A technique has been developed to provide real-time imaging, with several nanometer resolution, of organometallic chemical vapor deposition (CVD) by scanning electron microscopy under conditions approaching those used in the microelectronics industry. The technique involves modifications to an environmental scanning electron microscope (ESEM) to facilitate organometallic precursor gas handling and sample heating. To demonstrate the usefulness of this technique for studying the microstructural evolution of CVD-grown metal films, results of Al/SiO2 CVD experiments are presented.

Journal Article↗

PubMed1988

Blood vascular organization of the human appendix: a scanning electron microscopic study of corrosion casts.

Blood vascular beds of the human appendix were reproduced with a methacrylate casting medium and observed with a scanning electron microscope. The appendix received some small afferent arterial branches of the appendicular artery. These small arterial branches pierced the muscular layer and reached the submucosal plexus. Small arterioles arising from this plexus, climbed the mucosa and formed honeycomb-like capillary meshes at the luminal surface level. These capillaries were drained by the collecting veins, which descended the mucosa and joined the submucosal plexus. The large efferent veins arising from the submucosal plexus passed through the muscular layer and continued with the appendicular vein. In the mucosal and submucosal layers, several spherical basket-like casts of the germinal center (lymphoid follicle) were seen. In the parafollicular region (primary follicle), casts of postcapillary venules with prominent surface undulations were relatively frequently observed.

Adult↗

PubMed1975

Scanning electron microscope observations of the outgrowth from embryonic chick dorsal root ganglia in culture.

Cultures of chick dorsal root ganglia were examined with the scanning electron microscope. Fibroblasts, Schwann cells and neurites with their characteristic terminal filamentous growth cones were identified and their surface ultrastructure and inter-relationships described. Although exploratory filopodia of nerve growth cones were observed to pass both over and underneath the edges of wandering fibroblasts present at the periphery of the outgrowth, it was noted that the nerve bundles ultimately came to overlie sheets of fibroblasts. The neurites appeared generally bare along their lengths but were sometimes attached to the substrate or underlying fibroblastic sheet by small lateral projections. Some Schwann cells were observed to migrate freely between the neurites whilst others appeared to have wrapped around the nerve bundles in a manner suggestive of early myelination.

Animals↗

PubMed1977

The sub-membrane reticulum of the human erythrocyte: a scanning electron microscope study.

A web-like reticulum underlying the human erythrocyte membrane was studied at a resolution of 5-10 nm by means of scanning electron microscope. The network was visualized in isolated membranes (ghosts) torn open to reveal their interior space and in residues derived from ghosts extracted with Triton X-100. It formed a continuous (rather than patchy) cover over the entire cytoplasmic surface, except where lifted off or torn away. Filaments (5-40 nm in diameter), annular figures (40-60 nm in diameter), and nodes (30-100 nm in diameter) were prominent in different networks. The dimensions of the filaments and the interstices in the reticulum varied with conditions, suggesting that the network has elastic properties. This reticulum is probably related to the erythrocyte membrane proteins spectrin and actin.

Cell Fractionation↗

PubMed1990

Density of epithelial cells in the normal human nose and the paranasal sinus mucosa. A scanning electron microscopic study.

214 biopsies of mucosa from various sites of the nose and paranasal sinuses were obtained post-mortem and examined using the scanning electron microscope. The density of ciliated cells was increased in the nasal cavity, in the antero-posterior direction. In paranasal sinuses the density of these cells was high, except near the ostium of the maxillary sinus, where the density was decreased by half. Non-ciliated epithelial cells were found in relatively few areas: anterior aspect of the middle and lower turbinates, anterior septum. However, no uniform distribution of these cells was present. The density of goblet cells was significantly lower in the paranasal sinuses as compared to the nasal cavity, with the highest density being found near the ostium of the maxillary sinus.

Aged↗

PubMed1995

Heterodoxus spiniger (Boopiidae, Mallophaga) from Canis familiaris from India in the light and scanning electron microscopes.

Knowledge of morphometric characteristics of Heterodoxus spiniger was widened on the basis of material collected from dog (Canis familiaris) from India. Study, mostly by scanning electron microscope, concerned the males, females and nymphs of H. spiniger. The functional role of some elements, particularly observed surface ultrastructures, has been pointed out. The differences between postembrional stages were determined as well as literature data on H. spiniger were critically analysed.

Adaptation, Physiological↗

PubMed2001

Scanning electron microscopic study of the posterior ciliary veins in domestic ungulates.

Vascular corrosion casts of 12 equine, 15 bovine and 50 porcine eyes were studied scanning electron microscopically for the presence of posterior ciliary veins. These veins drain a postequatorial segment of the choroid and emerge near the posterior bulbar pole. They complement the four vorticose veins that emerge near or at the equatorial zone of the eyeball and the slender choroidoretinal veins that drain the peridiscal area of the choroid. Posterior ciliary veins were observed in all equine and bovine eyes examined. In these species they presented a large variation in size, number and position. In contrast, posterior ciliary veins were only present in two porcine eyes where they were represented by one and two vessels, respectively. The morphology and variability of these vessels is illustrated and their nomenclature and functional significance are discussed.

Animals↗

PubMed1987

Blood vascular architecture of the rat parathyroid glands: a scanning electron microscopic study of corrosion casts.

Blood vascular beds of the rat parathyroid glands were reproduced with a methacrylate casting medium and observed with a scanning electron microscope. The rat possesses only a single pair (one left and the other right) of parathyroid glands. Each gland was found to contain a rich capillary network which was completely isolated from the capillary plexus of the thyroid gland. Each parathyroid gland received some small afferent arteries from the superior thyroid artery and emitted a thick efferent vein continuous with the superior thyroid vein. The capillary network of the parathyroid gland consisted of freely anastomosing capillaries. The afferent arteries were divided in the superficial and deep layers of the gland. The thick efferent vein arose in the deep layer of the gland. Some small or accessory efferent veins arose in the superficial layers of the gland. These also drained into the superior thyroid vein.

Animals↗

PubMed1986

Architecture of swine lymphnode: light- and scanning electron microscopical studies.

The overall architecture of the swine lymphnode was studied on: nodes injected for the visualization of the lymph pathway, serially sectioned nodes, and material processed for scanning electron microscopy. Despite the commonly reported scheme of the node architecture, cortical-like and medullar-like tissue appeared to be intermingled seemingly with no rules in the node substance. Thus it was not uncommon to find cortical-like tissue in a peripheral position like in other mammals. A scheme of the node organization is proposed and the features of the different components of the parenchyma are described with particular emphasis on the lymphatic sinuses and the lymph pathway. Finally, scanning electron microscopical data on swine nodes are discussed and comparison made with observations reported for other mammals.

Animals↗