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PubMedDate not supplied

Immunological function of human tonsil. Surface topology of human tonsil lymphocytes using the scanning electron microscope (SEM).

The surface topology of the lymphocytes in human tonsils was performed by means of the scanning electron microscope (SEM). It was revealed that human tonsils consist of both 40.7% villous and 26.6% smooth surface lymphocytes. In general, the percentage results agree with those of E and EAC binding lymphocytes of human tonsils, as previously reported. Our serial experiments using immunological techniques proved the existence of two lymphocytes (T and B cell) having immunological roles.

Adolescent↗
PubMed1986

Scanning electron microscopical study of the effects of crystalloid and water-soluble glucocorticoids on articular cartilage.

A comparative scanning electron microscopical study on the topical effects of glucocorticoids on rat knee cartilage was undertaken. Water-soluble and crystalloid 'depot'-form glucocorticoids were tested. Cartilage destruction was dependent on the number of injections and was clearly more pronounced in the knees injected with crystalloid glucocorticoid. We conclude that repeated injection of the joint with glucocorticoids should be given only after careful consideration of the clinical state.

Animals↗
PubMed1976

[Study of aseptic inflammation using the scanning electron microscope].

A focus of inflammation in the subcutaneous connective tissue in white rats was investigated in a scanning electron microscope. Lymphocytes, polyblasts, macrophages, fibroblasts, collagenous fibres, gigantic multinuclear cells, vessels are described. Similiarity in the form and structure of the surface in agranulocytes of the blood, polyblasts and macrophages was established. A considerable change in morphology of fibroblasts, particularly in the period of synthesis os of the cell, was observed. Collagenous fibres and fibroblasts played a leading role in the creation of the supporting-mechanical carcass and in spatial structure of the regenerating connective tissue.

Animals↗
PubMed1999

Tannic acid and thiocarbohydrazide as structural reinforcement agents in the preparation of rabbit knee articular cartilage for the scanning electron microscope.

Samples from seven sectors of the rabbit knee articular cartilage were shaved and prepared for the scanning electron microscope using either tannic acid, thiocarbohydrazide or nothing (control). Surface morphology was found to be more typical to a given sector and less so to a specific preparation procedure. Rough areas were recorded from load-bearing sectors, while smooth areas appeared on load-free ones. However, fibrillations were discerned on control load-bearing sectors only, and pits and humps were never detected. Tannic acid and thiocarbohydrazide may have exerted their structural reinforcing effect on the tissue preservation by enhancing the binding of osmium tetroxide to it, possibly along with that of other soluble tissue constituents.

Animals↗
PubMed1986

Scanning electron microscope study of the predentin-pulpal border zone in human dentin.

Fragments of sound human molars were prepared for the scanning electron microscope (SEM) using modified fixative procedures and the carbon dioxide critical-point method to study the predentin-pulpal border zone. This technique minimizes the usual artifacts related to SEM procedures. The elongated odontoblast bodies are closely related to each other at the predentin level. For the first time in SEM procedures, the cell processes almost completely fill the predentinal tubules. Fibers measuring 0.3 to 0.5 micron in diameter are visible between the odontoblasts and fan out into the predentin. They correspond to the so-called Korff's fibers. Others, measuring less than 0.2 micron in diameter, are visible on the predentinal surface and follow the cell processes into the predentinal tubules. They correspond to nerve fibers. This study demonstrates that the proper use of improved SEM fixative techniques and the carbon dioxide critical-point method provides data on the relation between the different components of the predentin-pulpal border zone, which are in agreement with transmission electron microscope data.

Dental Pulp↗
PubMedDate not supplied

Human articular cartilage during osteoarthrosis: a study under the scanning electron microscope.

The present study has been carried out with the aim of contributing, by means of the Scanning Electron Microscope (SEM), to the understanding of morphological changes in human articular cartilage during osteoarthrosis. Fragments from the femoral head of 10 patients subjected to total hip joint prosthesis were cryofractured and then studied by SEM after treatment with current procedures. The images obtained were considered observing the division of cartilage into superficial, medium and deep layers. The superficial layer is the one which suffers most seriously during osteoarthrosis, but collagen alterations, as fibrillation, involve all the layers together. Moreover, the observation of deformed cellular lacunae in the deep layer suggests that a precocious functional collapse involves the whole thickness of the cartilage, probably due to a metabolic suffering.

Aged↗
PubMed1990

[The enamel surface quality after interproximal stripping--a scanning electron microscopic assessment of different polishing procedures].

The surface features of stripped human enamel were studied with the scanning electron microscope. The efficiency of rotating diamond and polishing discs was compared with that of diamond and polishing strips in a newly developed handpiece. Interproximal stripping with fine and superfine grit diamond coated discs and strips created furrows which were 10 microns in width. At the interface between treated and untreated enamel no hard tissue damage could be observed. Under in vitro conditions the furrows resulting from stripping were almost totally eliminated by using aluminum oxide coated strips or discs in automatically driven handpieces. After 60 s of polishing with each polishing strip/disc the treated enamel surfaces were nearly smooth. Only a few isolated furrows of 1 to maximum 3 microns were detected. As a result, we can state that it is possible to produce surfaces which are smoother than untreated natural enamel with the rotating or the oscillating polishing procedure.

Dental Enamel↗
PubMed1982

Development of neuroepithelial bodies in pre- and postnatal mouse lungs: scanning electron microscopic study.

The development of pulmonary neuroepithelial bodies (NEBs) in pre- and postnatal mice were studied with scanning electron microscope. In the fetuses, at 17 days' gestation, the NEBs were recognized as slight epithelial elevations covered by developing Clara cells. At 18 days, the small apical surfaces of the specialized cells began to be exposed to the bronchiolar lumen. At 19 days (full term), numerous microvilli-covered surfaces of the specialized cells were located between the dome-shaped Clara cells. At this stage, the boundary of the NEBs was well outlined by the developing ciliated cells. In the postnatal animals, the surface structure of the specialized cells remained the same as that of the 19-day fetuses, but the modified Clara cells gradually became wide and flat. In older mice, some NEBs formed obvious spherical mounds projecting into the bronchiolar lumen. The rapid differentiation of the microvillar projections on the surfaces of the specialized cells shortly before birth should provide the animals ample surface area to make contact with the airway contents.

Animals↗
PubMed1980

The morphology of cultured melanophores from tadpoles of Xenopus laevis: scanning electron microscopical observations.

Tail-fin melanophores of tadpoles of Xenopus laevis (Daudin) in primary culture were examined scanning electron microscopically in the aggregated and in the dispersed state. After isolation, the melanophores are spherical, but within 24 h they develop thin filopodia for attachment to the substratum. Subsequently, cylinder-like as well as flat sheet-like processes are formed, which adhere to the substratum with terminal pseudopodia and filopodia. The processes of adjacent melanophores contact each other, thus forming an interconnecting network between the melanophores. In the aggregated state the central part of the melanophore is spherical and voluminous. Both the central part and the processes bear microvilli. In melanophores with dispersed melanosomes the central part is much flatter; the distal parts have a thickness that equals a monolayer of melanosomes. The surface of the cell bears only scarce microvilli. These features indicate that melanophores do not have a fixed shape and that pigment migration is accompanied by reciprocal volume transformation between the cell body and its processes.

Animals↗
PubMed1990

Scanning electron microscope observations on collagen fibers in human dentin and pulp.

Human permanent teeth were examined in the scanning electron microscope after demineralization and exposure to preparative procedures based on hydrogen peroxide, trypsin, and EDTA. These substances removed the inorganic material, the cellular structures, the homogeneous connective tissue ground substance, and interfibrillar matrix. The remaining tissue components comprised a network of distinct collagen fibers whose organization was related to the type of tissue in which these were incorporated. A similar or identical method has not been developed or applied to teeth previously. Dentin and predentin comprised a compact mass of fibers which basically were parallel to the continuously growing interior surface of the predentin, or arranged at an acute angle to this plane. Collagen fibers in the pulp were numerous, but lacked any particular orientation in most areas. Interodontoblastic fibers crossed the odontoblastic zone at a right angle to the pulp chamber wall and mingled with collagen fibers in predentin. When previously published findings of ours are taken into account, it is possible to conclude that other factors than the organization of the collagen fibers are responsible for the stainability of these fibers in predentin and in interglobular dentin with silver methenamine, and that aldehyde groups on collagen fibers in predentin may be actively and directly involved in the mineralization of the dentin.

Collagen↗
PubMedDate not supplied

Structural changes in the fibrin network of a pretoria family with dysfibrinogenemia: a scanning electron microscopical study.

Inborn errors of fibrinogen structure are by definition congenital dysfibrinogenemias. The present study assesses the scanning electron microscope characteristics in the fibrin network morphology in a Pretoria family with an amino-acid substitution defect at position 139 on the gamma chain where the cystein residue is replaced by tyrosine. This anomaly results in a disturbance of the interchain disulfide bond, an ultrastructural defect that interferes with fibrin polymerization. Clinical manifestations showed that 2 of the family members presented with thrombosis, as well as a bleeding tendency, while 2 were asymptomatic. Fibrin clot analysis revealed that in all 4 family members a tighter fibrin network with increased fibrin density and reduced pore size was present. The fibers showed a "stellate" appearance where they converge and some were fused longitudinally to form sheets of "matted" fibrin. Furthermore, there was a conspicuous absence of platelets. Fibrin dysfunction is associated with the development of vascular complications, while proneness to the formation of tight and rigid fibrin networks is independently associated with thrombotic disease. Although this does not explain the proneness of some family members who present with excess bleeding, bleeding might be related to the defective binding of fibrin to activated platelets, resulting in inadequate prothrombotic stimulus that is normally enhanced by the second wave of thrombin generation, which occurs on the platelet surface.

Afibrinogenemia↗
PubMed1995

A light and scanning electron microscopic evaluation of electro-discharge-compacted porous titanium implants in rabbit tibia.

This study used light and scanning electron microscopic (SEM) histomorphometric methods to quantitate the rate of osseointegration of totally porous titanium alloy (Ti-6Al-4V) implants prepared by a novel fabrication technique--electrodischarge compaction (EDC). EDC was used to fuse 150-250-micrometer spherical titanium alloy beads into 4 X 6 mm cylindrical implants through application of a 300-microsecond pulse of high-voltage/high-current density. Two sterilized implants were surgically placed into each tibia of 20 New Zealand white rabbits and left in situ for periods corresponding to 2, 4, 8, 12, and 24 weeks. At each time point, 4 rabbits were humanely killed, and the implants with surrounding bone were removed, fixed, and sectioned for light and SEM studies. The degree of osseointegration was quantitated by means of a True Grid Digitizing Pad and Jandel Scan Version 3.9 software on an IBM PS/2 computer. The total pore area occupied by bone was divided by the total pore area available for bone ingrowth, and a Bone Ingrowth Factor (BIF) was calculated as a percent. The light microscopic results showed BIFs of 4% at week 2, 47% at week 4, 62% at week 8, 84% at week 12, and greater than 90% at week 24. The SEM results showed BIFs of 5% at week 2, 34% at week 4, 69% at week 8, 75% at week 12, and in excess of 90% at week 24. The results of this study show that EDC implants are biocompatible and support rapid osseointegration in the rabbit tibia and suggest that, after additional studies, they may be suitable for use as dental implants in humans.

Alloys↗
PubMedDate not supplied

Accuracy and precision of quantitative energy-dispersive x-ray spectrometry in the environmental scanning electron microscope.

The accuracy and precision of quantitative energy-dispersive x-ray spectrometry in the environmental scanning electron microscope have been estimated using a series of copper / gold alloys of known composition. The mean values (five to six replicate experiments) had relative errors within +/- 5%, and most were within +/- 3.5%. All relative standard deviations were < 5% and most were < 3%. Since the standard specimens were large (approximately 500 microm) in diameter, electron scattering in the 2 torr of water vapor above the specimen did not affect the results. This level of accuracy and precision was possible only by using a novel specimen surface charge neutralization scheme.

Journal Article↗
PubMed1998

Low-cost image-capture system for a scanning electron microscope.

We describe a PC-based active-capture system for recording digital images from a scanning electron microscope. The system is based on a National Instruments data-acquisition board and a Pentium computer, controlled by software that we have written in Visual Basic.

Journal Article↗
PubMedDate not supplied

Scanning electron microscopic observation of the foetal labyrinthine vestibule.

Vestibular portions of three foetal inner ears were examined by scanning electron microscope. The sensory cells from a 14-week foetus showed a coexistence of hair bundles of different lengths, indicating that the sensory cells were still in the developing stage. An 18-week foetus showed more developed hair bundles. A distinct kinocilium and unidirectional polarization of sensory cells were clearly seen even in the young short hair bundles. In all foetuses examined, non-sensory ciliated cells were found located on the vestibular wall between the utricular macula and all three cristae ampullares. These ciliated cells seem to disappear with maturation because these cells were not found in other postnatal inner ear specimens examined by the same method.

Ear, Inner↗
PubMed1983

Precisions on normal surface of human corneal epithelium: a scanning electron microscopic study.

We are describing the surface of the epithelium of the normal human cornea studied under the scanning electron microscope, and we describe the differences between the light and the dark cells at greater magnifications as well as the junctions between them. There are microplicae and microvilli which reveal differences both with regard to appearance and number, depending upon whether one is studying the light or dark cell.

Cornea↗
PubMed2006

Scanning electron microscopic evaluation of enamel surfaces exposed to 3 orthodontic bonding systems.

INTRODUCTION: This in-vitro study investigated the effects of conventional etching with a 35% phosphoric etching gel and priming/bonding with Transbond XT primer/adhesive (3M Unitek, Monrovia, Calif), conditioning with 10% polyacrylic acid and bonding with a resin-modified glass ionomer cement (Fuji ORTHO LC, GC Corporation, Tokyo Japan) or using a self-etching bonding system (Transbond Plus) and bonding with Transbond XT adhesive on the surface morphology of the enamel. The study was conducted at the Faculty of Dentistry, University of Oslo, in Norway, 2004. METHODS: The enamel surfaces of extracted premolars where conditioned with 1 of the 3 systems and evaluated with environmental scanning electron microscope. Brackets were then bonded with 1 of 3 bonding agents and examined with a conventional scanning electron microscope. RESULTS: The bonding systems induced different effects on the enamel structure. Phosphoric acid etching produced a rough, etched surface with the typical honeycomb pattern. Bonding brackets to such a surface resulted in thick resin tags relatively deep into the enamel. Less pronounced etching of the surface enamel was obtained by the self-etching primer system, and bonding resulted in smaller and fewer resin tags. The resin-modified glass ionomer bonded after conditioning the enamel with polyacrylic acid showed no resin tags. CONCLUSIONS: Bonding systems with self-etching primers or conditioners with polyacrylic acid might offer potential benefits compared with conventional acid etching and priming because of fewer irreversible changes to the enamel surface.

Acid Etching, Dental↗