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Results for “Microscopy, Electron, Scanning”

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PubMed1989

Cardiac myxomas correlative study by light, transmission, and scanning electron microscopy.

A correlative morphologic study of 17 cardiac myxomas surgically excised or observed at autopsy was performed by light (LM), transmission (TEM), and scanning electron microscopy (SEM). Tumor cells occurred singly (frequently in lacunae), in cords, as vascular-like aggregates, and in complex interdigitating clusters. By TEM, myxoma cells were predominantly undifferentiated mesenchymal cells. The surface topography by SEM revealed numerous clefts and crevices and a continuous cellular lining which, by TEM, appeared to be derived from underlying myxoma cells. The myxoid stroma by SEM was interspersed by numerous reticular fibers that appeared as a sponge-like supportive framework. Complex patterns of interdigitating myxoma cells corresponded well with similar patterns by LM and TEM, demonstrating the advantage of SEM in correlative morphologic studies.

Adolescent↗

PubMed1986

Scanning electron microscopy of Bunostomum phlebotomum (Railliet, 1900).

Live specimens of Bunostomum phlebotomum were collected from the small intestine of a calf and processed for scanning electron microscopy using standard methods. This paper describes the surface morphology of adult worms. All these hookworms showed a dorsally bent anterior end with its buccal capsule, which opens antero-dorsally with a pair of chitinous cutting plates on the ventral margin. Prominent cervical papillae and a well developed male bursa with a dorsal and 2 lateral lobes, were observed. The female tail is slender and pointed with the anal opening close to the tip. Further studies are necessary to demonstrate morphological differences from other hookworms and to obtain more detail of the male bursa and female tail.

Ancylostomatoidea↗

PubMed1984

[The endometrium of the immature rabbit stimulated by an estrogen and treated with a progestogen. Scanning electron microscopy study].

The endometrium of rabbits, treated by the usual pharmacology methods designed for the measurement of the pseudogestagen effect, was studied by scanning electron microscopy. Estrogen stimulation was followed by a multiplication of the number of ciliated cells. Treatment with progesterone lead to a decrease in the numbers of microvilli and to the appearance of rounded bulges which increased in numbers as the progesterone dose level increased. These changes were quite close to those observed in post menopausal women under estro-progestogen treatment.

Animals↗

PubMed1984

[The endometrium of intact or castrated rats. Effects of hormonal stimulation. A scanning electron microscopy study].

The endometrium of female rats during the estrous cycle and of female ovariectomised rats under hormone stimulation, has been studied by scanning electron microscopy. The endometrium underwent marked cyclical changes; the development of microvilli was noted before ovulation, and secretory phenomena started during proestrus but remained discrete throughout the cycle. The rat endometrium was also characterised by the fact that ciliated cells were scarce. Following ovariectomy, the endometrial surface pattern was similar to that of the menopausal woman endometrium. After estrogen or estroprogestogen stimulation, by the methods usually employed in endocrine pharmacology, the general endometrial pattern was very different to that observed during the reproductive cycle in rats.

Animals↗

PubMed1982

Scanning electron microscopy of rabbit corneal scars.

Central full-thickness perforating excision wounds were made in rabbit corneas and were examined by light and scanning electron microscopy at various times after wounding to study the three-dimensional morphologic changes in the tissue during healing and remodeling. Formation of a fibrin clot soon after wounding seals the hole and functions as a substrate for the healing epithelium. Changes in the histologic appearance of the fibrin lot immediately below the new epithelium are followed by migration of adjacent stromal cells under the epithelium, parallel to the basal surface of this tissue. Further healing is characterized by the organization of stromal fibroblasts into several layers parallel to the corneal surface and the deposition of collagen as a matted meshwork of fibrils tangential to the cell surface. Although remodeling of the collagenous matrix of corneal scar is evident and the scar eventually appears less opaque, the lamellae of the scar are narrower and shorter than normal. Evidence from this and other studies suggests that the orientation of the fibroblasts in healing tissues is determined by the organization of the newly formed epithelium. Furthermore, our observations are consistent with the hypothesis that collagen fibrils are deposited parallel to the flat surface of the fibroblasts during scar formation. Subsequent reorganization of this collagenous matrix approaches the normal lamellar appearance, but the matrix fails to regenerate even after 2 years.

Animals↗

PubMed1981

Scanning electron microscopy of rat degenerated hepatocytes after carbon tetrachloride intoxication.

Intracellular structures of hepatocytes were studied in rats intoxicated with carbon tetrachloride (CCL4) by scanning electron microscopy (SEM). Liver tissues were treated successively by conductive staining, critical point drying and fracturing with a scalpel. Fractured hepatocytes were mainly observed in the specimens 12 hours after CCL4 administration, Hepatocytes near the portal tract showed a normal dense cytoplasm. Swollen foamy hepatocytes were remarkable in the intermediate zone. They had numerous vesicles, 0.6-2.5 micrometer in diameter, which correspond to dilated cisternae of rough endoplasmic reticula (RER) observed by transmission electron microscopy. The vesicles were separated by a thin rim of the cytoplasm and communicated with each other through a round window. Besides vesicles, the foamy hepatocytes had some vacuoles 3-10 micrometer in diameter, which were extremely dilated RER. The vacuoles had many windows and communicated with the vesicles. Hepatocytes with dense cytoplasm and many vacuoles were distributed widely in the lobule. They were intermingled with the vesiculated hepatocytes inthe intermediate zone. Their vacuoles were 1.5-3.0 micrometer in diameter and some vacuoles communicated with each other. The vacuole had a well-developed wall with 0.1 micrometer diamter pores. The pores were sometimes arranged in line. Hepatocytes near the central vein showed necrotic changes. Most membraneous structures were disrupted except for fat droplets and the nucleus. The nucleoplasm was looser and nuclear pores disappeared. In summary, SEM demonstrated three-dimensionally organelle changes of hepatocytes induced by CCL4 administration.

Animals↗

PubMedDate not supplied

[Scanning electronic microscopy of the small intestine in persistent diarrhea].

Persistent diarrhea very often leads children to malnutrition. It has become the major cause of death resulting from acute diarrhea episodes in developing countries. In order to determine the ultrastructural alterations of the small bowel that occur in the syndrome, 16 infants with severe persistent diarrhea were studied, utilizing light microscopy and the scanning electron microscope. Stool and jejunal fluid samples were collected for culture, rotavirus, ova and parasite search. Enteropathogenic agents were isolated in stools from 11 (68.7%) patients and bacterial proliferation in the small bowel was detected in 11 (68.7%) patients. EPEC strains were the most frequent enteropathogenic agent isolated both from stool and jejunal fluid cultures. The stool cultures revealed the presence of the following enteropathogenic microorganisms: EPEC 0111 in four, EPEC 0119 in one, EAggEC in five, Shigella flexneri in two, and Shigella sonnei in one; mixed infections due to EAggEC associated with EPEC 0111 were seen in two patients. The light microscopic analysis revealed that 56.2% of the patients suffered moderate villous atrophy most frequently associated with effacement of the microvilli, intracytoplasmatic vacuolization, increased number of multivesicular bodied and increased lymphocytic and eosinophylic infiltration in the lamina propria. The scanning electron microscopic analysis revealed in all cases shortening of the villi and enterocyte derangements; very often there was a total lack and/or effacement of the microvilli; in half of the patients there was a mucoid material covering the enterocytes tightly adhered to the apical epithelium surface. The scanning ultrastructural alterations observed in these patients are probably due to an association of factors brought about by the presence of enteropathogenic microorganisms and the resulting food intolerance that is responsible for perpetuation of diarrhea.

Diarrhea, Infantile↗

PubMed1996

Problems in preparation of chromosomes for scanning electron microscopy to reveal morphology and to permit immunocytochemistry of sensitive antigens.

Although much information about chromosome structure and behaviour has been obtained using light microscopy, greater resolution is needed for a thorough understanding of chromosome organisation. Scanning electron microscopy (SEM) can provide valuable data about these three-dimensional organelles. The introduction of methods using osmium impregnation of methanol-acetic acid-fixed chromosome spreads revolutionised matters, producing life-like images of chromosomes. Nevertheless, it became clear that osmium impregnation introduced various artefacts, although the resulting images were still useful. Methanol-acetic acid-fixed chromosomes are, in fact, flattened on the glass substratum, and the 3-dimensional appearance obtained after osmium impregnation is the result of swelling during this process. At the same time, the fibrous substructure of the chromosomes becomes much coarser. More recently a number of alternative methods have become available for studying chromosomes by SEM. Isolated chromosomes, that have not been allowed to dry during preparation, retain a 3-dimensional appearance without osmium impregnation, and the same is true of methanol-acetic acid-fixed chromosomes that have been treated with 45% acetic acid and processed without drying; however, these methods do not permit the routine production of intact metaphase spreads. Use of cytocentrifuge preparations obviates the use of acetic acid fixation and osmium impregnation, produces intact metaphase spreads, and permits the immunocytochemical detection of antigens that are easily destroyed by routine fixation procedures.

Acetic Acid↗

PubMed1976

Scanning electron microscopy of normal uterine cervix, carcinoma in situ and squamous cell carcinoma. Preliminary findings.

Colposcopically directed punch biopsy specimens of the uterine cervix were taken from women in whom Papanicolaou smears indicated cytological abnormalities. Half of each specimen was processed for scanning electron microscopy and half for light microscopy. The surface morphology of normal cervical, metaplastic and frankly carcinomatous epithelia and epithelia of carcinoma in situ, as seen under the scanning electron microscope, was compared with the appearance revealed by Papanicolaou smears, and haematoxylin- and eosin-stained sections.

Carcinoma in Situ↗

PubMed1977

Effect of pretreatment with ethanol containing fluoride on etched enamel surface as evaluated by scanning electron microscopy, optical microscopy, and tensile bond strength measurement.

The effects of pretreatment with a fluoride-containing ethanol solution on etched enamel surfaces before application of sealant were examined using scanning electron microscopy, optical microscopy, and tensile bond strength determinations. The results suggested that when etched enamel surfaces are treated with ethanol containing no more than 250 ppm fluorine in potassium fluoride, there is no interference with the bonding of the sealant to the treated, etched anamel surface.

Acid Etching, Dental↗

PubMed2001

Scanning electron microscopy determination of string mozzarella cheese in gastric contents.

As part of a suspected homicide investigation, a sampling of the gastric contents from the victim was forwarded to the U.S. Food and Drug Administration's Forensic Chemistry Center (FCC) for analysis of specific, selected components. The victim was known to have consumed string mozzarella cheese, as a snack, less than 24 h before his disappearance and the subsequent discovery of the body. The investigation sought to confirm or dismiss speculation the victim may have been fed a meal or eaten additional food prior to his death. Analysis of the stomach contents involved examination by stereoscopic light microscopy (SLM) and isolation, processing, and analysis of suspect materials by scanning electron microscopy (SEM). Several wax-like, off-white to cream-colored objects were noted by SLM examination and removed from the gastric contents. Through a series of fixation, sectioning, drying, and coating steps, these objects were prepared for analysis by SEM. Comparison of the suspect material with laboratory control string mozzarella cheese showed excellent correlation between the analyzed samples, confirming the suspect material from the stomach contents as string mozzarella cheese.

Cheese↗

PubMed1989

Scanning electron microscopy and gel electrophoresis of vascularized periosteal autografts.

This study was devised to investigate the morphologic and biochemical sequence of events occurring during early periosteal osteogenesis in vascularized periosteal flaps. A pleuroperiosteal flap based on the intercostal vessels was developed and rotated onto the chest wall in 12 adult dogs. Animals were sacrificed at intervals between 7 and 60 days, and the flaps were removed with the underlying muscular bed. Specimens were studied by tetracycline uptake, gel electrophoresis, light microscopy, and the scanning electron microscope. Osteoprogenitor cells were seen as early as 7 days after transfer. Collagen fiber deposition was vigorous and noted in all specimens with rapid mineralization by 9 to 15 days. There was no structural or vascular interaction between the flaps and the recipient muscular bed. Gel electrophoresis confirmed the presence of type I and III collagen, with an increase in type I collagen over time. The pattern of collagen deposition and the final bony architecture resembled that of woven bone.

Animals↗

PubMedDate not supplied

Comparison in spatial spreads of secondary electron information between scanning ion and scanning electron microscopy.

Monte Carlo simulations have been carried out to compare the spatial spreads of secondary electron (SE) information in scanning ion microscopy (SIM) with scanning electron microscopy (SEM). Under Ga ion impacts, the SEs are excited by three kinds of collision-partners, that is, projectile ion, recoiled target atom, and target electron. The latter two partners dominantly contribute to the total SE yield gamma for the materials of low atomic number Z2. For the materials of high Z2, on the other hand, the projectile ions dominantly contribute to gamma. These Z2 dependencies generally cause the gamma yield to decrease with an increasing Z2, in contrast with the SE yield delta under electron impacts. Most of the SEs are produced in the surface layer of about 5lambda in depth (lambda: the mean free path of SEs), as they are independent of the incident probe. Under 30 keV Ga ion impacts, the spatial spread of SE information is roughly as small as 10 nm, decreasing with an increasing Z2. Under 10 keV electron impacts, the SEI excited by the primary electrons has a small spatial spread of about 5lambda, but the SEII excited by the backscattered electrons has a large one of several 10 to several 100 nanometers, decreasing with an increasing Z2. The main cause of a small spread of SE information at ion impact is the short ranges of the projectile ions returning to the surface to escape as backscattered ions, the recoiled target atoms, and the target electrons in collision cascade. The 30 keV Ga-SIM imaging is better than the 10 keV SEM imaging in spatial resolution for the structure/material measurements. Here, zero-size probes are assumed.

Journal Article↗

PubMed2006

In vivo and in vitro study of porcine oviductal epithelial cells, cumulus oocyte complexes and granulosa cells: a scanning electron microscopy and inverted microscopy study.

The morphology and structure of porcine oviductal epithelial cells (POEC), cumulus-oocyte complexes (COCs) and granulosa cells (GC) were investigated in vivo and in vitro conditions using scanning electron microscopy (SEM) and inverted microscopy. The POEC contained columnar ciliated cells and spherical shaped non-ciliated cells. Both non- and ciliated cells appeared either in groups or distributing among each other. However, the isolation of cells was observed after culture for 48 h. A total of 921 oocytes from 20 ovaries was isolated resulting in an average of 46 oocytes per ovary. They were round in shape, surrounded by zona pellucida with layers of cumulus cells ranging between 89.16 and 144.68 microm in size. As for COCs, they were classified into 4 types; intact-, multi-, partial-cumulus cell layers and completely denuded oocyte. Interestingly, changes in morphology of COCs with intact and multi-cumulus cell layers were observed in the in vitro study. The GCs in the follicular fluid were also round in shape and found as clusters. After culturing in in vitro for 48 h, no change in morphology was observed. The GC appeared in smaller clusters or were present as single cells and their sizes ranged from 6 to 8 microm. The results obtained from this study allow us to have a better understanding of the morphology and nature of cells under both in vivo and in vitro conditions. This information is also important for the study of their secretions and biochemical compositions, which is of great importance to the use of cells as feeder cells in in vitro fertilization in current studies.

Animals↗

PubMed1987

Scanning electron microscopy in the backscattered electron imaging (BEI) mode: applications to clinical hematology.

Elements of high atomic number backscatter electrons that carry information of cytochemical and of immunocytochemical significance in high resolution scanning electron microscopy (SEM). Reaction products of enzyme cytochemistry containing lead or osmium have been used to localize the sites of phosphatase and of endogenous peroxidase, respectively. Particles of colloidal gold, ranging in diameter from 40 to 13 nm, have been successfully used to label cell surface antigens specifically identified by murine monoclonal antibodies. The diagnostic potential of the scanning electron microscope in clinical hematology appears to be considerably enhanced by the use of the backscattered electron imaging (BEI) mode. Quantitation of the number of gold-labeled epitopes on cell surfaces cannot be achieved in the conventional secondary electron mode of the SEM, but is an attractive possibility in the backscattered electron imaging mode.

Antigens, Surface↗

PubMed1985

Differentiation of Pseudomonas aeruginosa and Enterobacteriaceae in direct smears based on measurements by scanning electron microscopy.

We believe that experienced observers can often distinguish between Enterobacteriaceae and Pseudomonas aeruginosa, by differences in dimensions in Gram-stained direct smears. Many microbiologists question whether this should be attempted because of overlap in dimensions. We have found that culture results confirm our observations about 80% of the time and that such reporting is helpful in diagnosis and treatment. We decided to try to verify the differences in dimensions objectively. Because of the limitations of making measurements by light microscopy, exudate from clinical specimens and from experimental mouse infections were examined by scanning electron microscopy. Discriminant function analysis was applied to the dimensions of length and width, and this showed that 83% of the organisms in both groups could be correctly classified on the basis of the dimensions. This supports our premise that experienced observers should be able to differentiate between these organisms in Gram-stained direct smears, using light microscopy with sufficient confidence to provide clinically useful information.

Animals↗

PubMedDate not supplied

Scanning electron microscopy studies of protein-functionalized atomic force microscopy cantilever tips.

Protein-functionalized atomic force microscopy (AFM) tips have been used to investigate the interaction of individual ligand-receptor complexes. Herein we present results from scanning electron microscopy (SEM) studies of protein-functionalized AFM cantilever tips. The goals of this study were (1) to examine the surface morphology of protein-coated AFM tips and (2) to determine the stability of the coated tips. Based on SEM images, we found that bovine serum albumin (BSA) in solution spontaneously adsorbed onto the surface of silicon nitride cantilevers, forming a uniform protein layer over the surface. Additional protein layers deposited over the initial BSA-coated surface did not significantly alter the surface morphology. However, we found that avidin-functionalized tips were contaminated with debris after a series of force measurements with biotinylated agarose beads. The bound debris presumably originated from the transfer of material from the agarose bead. This observation is consistent with the observed deterioration of functional activity as measured in ligand-receptor binding force experiments.

Adsorption↗

PubMed1984

Hyaline articular cartilage dissected by papain: light and scanning electron microscopy and micromechanical studies.

Papain was used to digest the hyaline femoral condylar cartilages of 30 adult Wistar rats. Matrix proteoglycan degradation was assessed by the light microscopy of paraffin sections stained with toluidine blue. The extent of surface structural change was estimated by scanning electron microscopy, and the structural integrity of the hyaline cartilage tested by the controlled impact of a sharp pin. The results demonstrated an early loss of cartilage metachromasia, increasing with time of papain digestion, and an alteration in the shape of the cartilage splits produced mechanically. Accompanying the loss of matrix material was a conspicuous sequence of morphological changes in cartilage surface structure. The results confirm a close relationship between matrix integrity, mechanical properties, and fine structure.

Animals↗