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Results for “scanning electron microscope”

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PubMed1991

Scanning electron microscope (SEM) study of mouse embryos obtained from isolated blastomeres.

Preimplantation diagnosis and embryo sexing offer great possibilities in the prevention of human diseases and in the field of animal production. These techniques involve blastomere isolation. Isolated blastomeres can grow in culture and develop as whole embryos. In this paper we describe, at the scanning electron microscope level, the characteristics of the plasma membrane surface of isolated blastomeres obtained from mouse embryos at the two-cell stage and of embryos grown to the 2/4- and 4/8-cell stages and compare them to control embryos grown in vitro. According to our results the in vitro manipulation of these embryos does not affect the surface characteristics of the plasma membrane in the early cleavage stages.

Animals↗

PubMedDate not supplied

The effect of fast secondary electrons on x-ray microanalysis in the scanning electron microscope.

In this paper, the effect of fast secondary electrons (FSE), which result from inelastic scattering of incident electrons, on the characterization of materials in the scanning electron microscope are investigated with the aid of Monte Carlo simulations. The effect of FSE on x-ray microanalysis of light elements is investigated. A full description of the Monte Carlo simulations of FSE in solids is given.

Boron↗

PubMed1982

A simple method for scanning electron microscope preparation of cells grown in multiwell culture plates.

The closeness of wells in multiwell tissue culture plates makes it difficult to remove individual ones without distributing the adjacent wells. Moreover, critical point drying frequently introduces artifact into the culture monolayer grown on plastic substrate. These problems make it difficult to process such cultures for scanning electron microscopy. However, for cell kinetic and correlative morphological studies on primary cultures derived from 7,12-dimethylbenz(alpha)anthracene(DMBA)-induced mammary tumors, we have found that Falcon 24-well tissue culture plates are excellent for maintenance of cells and are convenient to use. By plating the cells in alternating, diagonally disposed wells and while the cells are still in the buffer, individual wells can be cut from a multiwell plate without disturbing the cells in adjacent wells. The isolated wells can be used to carry out scanning electron microscope preparation. The height of the well is reduced with a scalpel prior to critical point drying; the remaining well is useful as a handle in mounting the dried sample to stubs for subsequent coating and viewing. Critical point drying and coating of monolayer samples on Falcon plastic are described. The results do not suggest that any artifacts are introduced in our preparations.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1990

[Scanning electron microscope view of dentin exposed to CO2 laser radiation].

In order to better define the effects of CO2 Laser rays on dentine, 10 healthy human teeth to be removed and 64 recently removed healthy human teeth were prepared and irradiated according to the classic protocol used in clinical periodontics, and observed with a scanning electron microscope. The examination of these samples confirms the phenomena of dentin fusion and recrystallization. But these alterations result in the appearance of a reorganized superficial layer consisting of unevenly juxtaposed craters formed by the pin-point action of the laser beam. These craters present numerous fissures and openings of variable diameter. They do not form a homogeneous surface, since chips may be raised, demonstrating the fragility of the reorganized layer and a lack of cohesion of the underlying dentine. The modified dentine layer also disappears when a curette is used, revealing a very uneven surface crossed with small cracks and where the tubule openings become visible. Our results, unlike many more optimistic studies, still prompt us to exert caution in the systematic use of CO2 lasers in Periodontics.

Adult↗

PubMed1996

Scanning electron microscopic study of the postnatal development of the rabbit cochlea, with an emphasis on innervation.

The development of nerve fiber arrangements of the organ of Corti was studied in rabbits 1, 3, 5, 7 and 12-days-old using thick sections from celloidin-embedded cochleas which were examined under a scanning electron microscope. The arrangements of nerve fibers varied with developmental age. The tunnel spiral bundle was thick and loosely collected in the immature cochlea. The outer spiral fibers were recognized even in the narrow space of Nuel in the one-day-old cochlea. As Nuel's space is extending, the fibers course along the medial side of Deiters' cells. The arrangement of the outer spiral fibers was irregular and sparse in the five-day-old cochlea, in contrast to the regular parallel pattern of the adult cochlea. Adult-like parallel arrangement of the outer spiral fibers was seen in the twelve-day-old cochlea. In the three-day-old cochlea, irregularly running nerve fibers were seen along the outer spiral fibers. They may be efferent axons which develop afterwards. Club-like immature nerve endings were recognized at the base of the outer hair cells in the seven-day-old cochlea. Some fibers climbed high up along the medial wall of the outer hair cells. A nearly mature pattern was seen in the twelve-day-old cochlea. This study confirms previous reports on the development of cochlear innervation.

Animals↗

PubMed1976

Uterine vasculature of the pregnant pig: a scanning electron microscope study.

Colored cold setting acrylic cement was injected through catheters into the arteries and veins of sixteen gravid uteri obtained from pigs at various stages of pregnancy. After the cement had set hard, the reproductive tracts were macerated in concentrated acid and the vascular casts resulting were washed clean of digested tissues. Small pieces of cast were coated with gold and viewed by means of a scanning electron microscope. Early in pregnancy the capillary network consists of low parallel ranks of ridges and troughs; later, cross ridging was observed which developed in complexity as pregnancy progressed. The density of capillaries comprising the microvascular network also increased towards term. No comparable changes were noted in the relatively less well vascularized areas surrounding the mouths of the uterine glands. This technique surmounted the problems of obtaining an adequate depth of focus for viewing the capillary network of the gravid uterus with the light microscope. The relationships that the blood vessels bore to the overlying epithelial layers were discussed and the inference tentatively drawn that blood flow at the capillary level was from ridge top to trough base.

Animals↗

PubMed1994

A comparison of conventional SEM techniques, low temperature SEM and the electroscan wet scanning electron microscope to study the structure of a biofilm of Streptococcus crista CR3.

Biofilms of Streptococcus crista CR3 were generated on hydroxyapatite (HA) discs for 20 h in a continuous flow system with brain heart infusion broth dripped over the disc at a rate of 6 ml h-1. This study compares the conventional scanning electron microscope (SEM) preparation techniques, of critical point drying and freeze-drying, with low temperature SEM (LTSEM) and Electroscan generated images of hydrated biofilms, which preserve the integrity of hydrated polymers. Critical point drying and freeze-drying caused almost complete disappearance of the matrix of extracellular polymeric substances (EPS). Critical point drying, however, showed evenly spaced single or paired cocci remaining on the HA disc whereas freeze-drying caused the biofilm to detach from the HA leaving only patchy clumps of cells visible. By comparison LTSEM preserved the EPS better than critical point drying and freeze-drying, but holes were seen in the top and side of the biofilm and the EPS did show some shrinkage artefacts. An untreated wet biofilm viewed in the Electroscan showed an intact, hydrated, smooth matrix of EPS with cell shapes only visible indistinctly in a canopy of moist EPS. No holes were visible and no shrinkage artefacts were evident. Therefore, Electroscan imaging of the biofilm was the only method that preserved the integrity of the matrix with no apparent shrinkage artefacts.

Histocytological Preparation Techniques↗

PubMed1991

[Scanning electron microscopic study of subchondral bone tissues in osteoarthritic femoral head].

In total hip replacement for 12 aged women with advanced osteoarthritis of the hip joint, three types of lesioned articular cartilage with various degrees of severity and ivory bone were obtained together with their subchondral bone tissues. These specimens were processed and studied under scanning electron microscope and were compared with sex and age-matched non-osteoarthritic femoral head articular cartilage specimens. In osteoarthritic femoral heads, with deepening of the articular lesion, the articular cartilage gradually became thinned out and eventually lost. The subchondral bone plate became markedly thickened in most of the specimens. The epiphyseal trabeculae were also thickened and turned rough so that the meshwork pattern gradually disappeared. The thickened trabeculae finally fused into a large piece of dense bone tissues without microfracture. These changes could be accounted for by the increased stress imposed on the subchondral bone tissues as a result of incompetence of the diseased articular cartilage. Consequently, the changes on the part of subchondral bone tissues of the osteoarthritic femoral heads were the sequent, rather than the cause, of the articular lesions.

Cartilage, Articular↗

PubMed1993

A scanning electron microscopic study of the degenerative cartilage in patellar chondropathy.

Patellar chondropathy as cartilage degeneration localized in patellar cartilage in young persons is characterized by cartilaginous changes, such as softening, swelling, and fissuring. With a view to structural characterization of early cartilaginous degeneration before erosion, the morphology of affected cartilage was studied under a scanning electron microscope. The surface network of cartilage constituting fibrils had an edematous change, presenting with fibrillation on the medial facet, whereas many fibrils of the central ridge had a collagen bundle, and fissuring of varying size was observed. It appeared that a mechanical force (shearing) acting on the site of the central ridge was associated with the formation of a collagen bundle and its destruction. On the lateral facet, fibrils were arranged perpendicular to the joint surface; the superficial layer of fibrils was worn by hyper-pressure acting on the lateral facet. On the fractured surface, the coarseness of collagen fibrils showed changes that varied with the site and stage of cartilage degeneration. Frequent changes were signs of fibril loosening (coarsening), such as reduction in fibril density (i.e., edematous change), collagen fibril aggregation, and fissuring, and longitudinal restructuring of fibrils. The patellar cartilage in the patients of this series showed a structure adapted to the mechanical force. The initial structural changes of cartilage consisted of collagen fibril aggregation and reduction in fibril density. These changes give rise to matrix rarefaction, which in turn causes cartilage degeneration to progress. These changes were concurrent in both the superficial and middle layers and were not localized as basal degeneration.

Adolescent↗

PubMed1983

Scanning electron microscope cytochemistry of normal and leukaemic leukocytes.

Backscattered Electron Imaging (BEI) is a particular technique which permits to study cytochemical reactions with the Scanning Electron Microscope (SEM). The BEI data pertaining to specific enzymatic activities can be directly correlated to the surface morphology of each individual cell. Leukocytes from 5 normal individuals, 14 patients with acute nonlymphoblastic leukaemia (ANLL), 7 patients with chronic myeloid leukaemia (CML) and 3 patients with acute lymphoblastic leukaemia (ALL) were studied for myeloperoxidase activity, acid phosphatase localization, silver staining of the nuclei and phagocytosis of iron carbonyl in the BEI mode of SEM. Some normal peripheral blood leukocytes which cannot be distinguished by their surface morphology alone were satisfactorily identified with the BEI technique. Leukaemic myeloid cells can be recognized in many cases because of their positive myeloperoxidase reaction, while monocytic elements can be characterized by the presence of surface ruffles, acid phosphatase activity and active phagocytosis. The usefulness of the BEI technique in identifying different blood cell types with the SEM and its possible application to the diagnosis of certain cases of leukaemia are discussed.

Acid Phosphatase↗

PubMed1991

Ultrastructural alterations of the myocardium induced by doxorubicin. A scanning electron microscopic study.

Morphologic changes in Doxorubicin (DXR)-induced cardiomyopathy are characterized by marked dilatation of the sarcoplasmic reticulum (SR). DXR was administered to New Zealand White rabbits for 5 or 8 weeks and the three-dimensional structure of the sarcotubular system in cardiac muscle cells from each rabbit was examined under a field-emission type scanning electron microscope (SEM) after removal of cytoplasmic matrices by the osmium-DMSO-osmium procedure. Five weeks after the initial injection of DXR, partial dilatation of the SR and damaged mitochondria with lysis of cristae were observed three-dimensionally. After 8 weeks, the three-dimensional structure of the SR showed extensive spherical ballooning which could be seen clearly in bold relief. Thus, we could directly visualize structural alterations of the sarcotubular system in DXR-induced cardiomyopathy using the SEM.

Animals↗

PubMed1996

Morphological abnormalities of rabbit spermatozoa studied by scanning electron microscope and quantified by light microscope.

Rabbit spermatozoa morphological abnormalities were examined to establish criteria for judging the quality of ejaculates. Ten New Zealand White bucks, aged 9 months and weighing 4.3 +/- 0.2 kg, were placed in a climatic chamber for 3 weeks at +20 degrees C and 70% RH. Sperm was collected three times a week using an artificial vagina. The use of a scanning electron microscope (from x 2000 to x 15,000) in this study produced an illustrated guide for the classification of abnormalities. Mean percentage quantitative values studied by light microscope (x 400) observation were: 18.2% total abnormalities, 2.9% head abnormalities, 13.6% tail abnormalities and 1.7% broken spermatozoa. Variability was very high (CV 35.7, 54.0, 45.3 and 32.5%, respectively); consequently, each ejaculate should be analysed before use for artificial insemination. Among the different tail abnormalities observed, the most frequent were coiled tails, 9.1%, cytoplasmic droplets, 2.4%, bent tails, 1.3% and swollen tails, 0.5%.

Animals↗

PubMed1990

[Scanning electron microscopic study of rat lungs in experimental chronic paraquat poisoning].

It is well known that Paraquat (1,1'-dimethyl-4,4'-bipyridylium dichloride), used widely as a herbicide, causes a primary toxic effect in the lungs of humans and laboratory animals. This paper describes the pulmonary changes of chronic paraquat poisoning in rats, comparing scanning electron microscopic findings. Twenty-four rats were given repeated injections of 10/kg body weight paraquat intraperitoneally for 6 consecutive months, and six control rats were given 0.9% NaCl solution. The animals exposed to paraquat showed thickening of alveolar septum, inflammatory cell infiltration, interstitial fibrosis, and marked proliferation of alveolar macrophages. Among them four rats (21%) showed the typical findings of diffuse pulmonary fibrosis. Lesions were more severe at the subpleural region of the lung. The desquamation of alveolar epithelial cells and subsequent exposure of the basement membranes were observed in places. Although alveolar epithelial cells both in the type I and the type II were prolific, the type II cells showed partial loss of microvilli and projections. These findings may indicate the lowering of the type II cell function and subsequent decrease of surfactant excretion which causes respiratory insufficiency. Furthermore, alveolar macrophages showed a tendency to increase in number with progressive development of fibrosis. This tendency may support the hypothesis by Schoenberger et al., in which alveolar macrophages release both fibronectin and a growth factor for fibroblast after paraquat exposure.

Animals↗

PubMed2000

Scanning electron microscopic findings of cleaved unfertilized eggs ovulated by repeated administration of gonadotrophin.

Oocytes in the degenerative process are suggested to be rescued and to developed to ovulation by repeated induction of superovulation using gonadotrophin (GTH). In this study, the morphology of abnormally cleaved unfertilized eggs obtained by repeated induction of superovulation in mice using PMSG/hCG was observed by scanning electron microscope. As a result, loss of microvilli was noted on the cell surface of cleaved unfertilized eggs. On the other hand, ample microvilli were observed on the cell surface of fertilized eggs in the morula stage obtained 65 hours after spontaneous copulation used as controls. Loss of microvilli on the cell surface is a characteristic finding in apoptotic cells. Cleaved unfertilized eggs obtained by repeated induction of superovulation using GTH are considered to be in the degenerative process due to apoptosis.

Animals↗

PubMed1990

[Scanning electron microscopic study of the reaction of ceramics implant in middle ear].

In this article, the reaction of ceramics implanted in cat's middle ear was observed and compared with autologous cortex bone and Teflon. The three types of graft were implanted in cat's middle ear. Then the cats were killed at one, two and four months after operation. The grafts were taken out and observed under scanning electron microscope. We found that the ceramics were coated by a continuous epithelium. Beneath this there were fibers and capillaries. These results indicated that Al2O3 ceramics are better than Teflon and is a good ossicular prosthesis.

Aluminum Oxide↗

PubMed1985

Implantation failure of peritoneal dialysis catheters: a scanning electron microscopical study.

Patients with end stage renal failure may be treated by continuous ambulatory peritoneal dialysis. The transcutaneous portion of the catheters used in this treatment is covered with porous expanded polytetrafluoroethylene (PTFE) to provide a surface suitable for tissue infiltration. Following some instances where catheters failed to become fixed in the abdominal wall, a scanning electron microscopical study was carried out to compare the infiltration of catheters having successful or unsuccessful implantation. The porous layer of a well-fixed catheter, removed after successful renal transplantation, was infiltrated with collagen fibrils and overlaid by layered connective tissue composed of fibroblasts and collagen fibre bundles, sometimes linking to surrounding muscle fibres. The examination of four unsuccessful catheters revealed no evidence for infection being the cause of implantation failure. However the porous surface of these catheters was filled with blood components and products, sometimes apparently laid down in layers, suggesting that frequent bleeding resulting from repeated trauma may be responsible for the failure of catheter fixation. These findings led to two changes in clinical practice with apparent patient benefit. The implantation site has been relocated to reduce chafing by clothing and the post-operative wound dressing technique has been altered to minimise catheter movement.

Catheterization↗

PubMed1996

Osteoclastic resorption of Haversian systems in cortical bone of femoral neck in aged women. A scanning electron microscopic study.

OBJECTIVE: To reveal the sequence of events of osteoclastic resorption taking place in the cortical bone of the femoral neck in aged women. MATERIAL AND METHODS: The cross sections of cortical bones of the femoral neck from 7 aged women who underwent endoprosthetic replacement for intracapsular hip fracture, were processed and subjected to scanning electron microscopic observation. RESULTS: The cortical bone sections revealed enlargement of the Haversian canals. On the inner linings of the enlarged canals many oval resorption lacunae could be found, reflecting osteoclastic resorption of the Haversian systems. The osteoclastic resorption with subsequent enlargement of the Haversian canals into round or oval cavities took place first over the inner portions of the cortical sections, thereby rendering these areas porotic (cancellization). These processes of the Haversian systems and canals then gradually emerged over the central and eventually over the outer areas of the cortical bone, and the entire cortical bone became porotic. Meanwhile, the inner porotic portion of the cortex turned into trabeculae (trabecularization) and became gradually resorbed, resulting in thinning of the medial cortex. CONCLUSIONS: Cortical cancellization, trabecularization and thinning compromised the material strength of the femoral neck so that fracture would ensue even with trivial injury.

Aged↗

PubMed1994

Apical marginal adaptation of orthograde and retrograde root end fillings: a dye leakage and scanning electron microscopic study.

A few studies have attempted to examine the correlation between clinical success of root canal therapy and in vitro examinations. In this case report we examined the apical adaptation of three orthograde fillings and four retrograde amalgam root end fillings from four radiographically successful teeth and one unsuccessful case by using dye leakage and scanning electron microscopic methods. Despite the radiographic appearance of successful root canal therapy, these examinations showed penetration of methylene blue dye through the apical foramina to the levels of the root canal filling materials in the roots treated nonsurgically and the presence of small gaps between filling materials and the dentinal walls. The methylene blue dye also penetrated through the interface between amalgam and root end cavities, and there were varying size gaps between the root end cavities and amalgam. Similar examinations on the radiographically unsuccessful retrograde filling showed the presence of gaps between the amalgam and the root end cavity preparation and complete penetration of methylene blue dye between amalgam, root canal filling materials, and the dentinal walls.

Aged↗