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PubMedDate not supplied

Scanning electron microscopy after cytologic examination of urinary cells: lack of diagnostic advantage using combined microscopy.

A simple method for combined light microscopy (LM) and scanning electron microscopy (SEM) of urinary sediment is described. Spontaneously voided cells were routinely collected onto a filter for cytologic study. Individual cells were photographed and demarcated by an ink grid pattern and puncture marks in the filter. The filter was prepared for SEM. The cells that were studied by LM could be readily located and examined by SEM. This study showed the importance of identifying individual cells before observation by SEM since cells with similar appearances by LM may have markedly different features by SEM, and vice versa. The results obtained in a series of patients with transitional-cell bladder carcinoma indicate that degenerative changes in voided urothelial cells negate the utility of SEM as a routine screening tool.

Carcinoma, Transitional Cell↗
PubMed1980

[Surface ultrastructure of the human uterine exfoliated endometrial cells--comparative studies of the same cell by light microscopy and scanning electron microscopy (author's transl)].

The preparations for observations of the same cells by light microscopy (LM) and scanning electron microscopy (SEM) were examined and the exfoliated endometrial cells of the uterus obtained by the newly introduced brush and cannula was evaluated. 1) The degree of shrinkage of the area was not significant between the air drying method and critical point drying method. In the air drying group, adhesion, entanglement and disappearance of microvilli (mv) and the adhesion of cilia, and the collapse of cells were noted morphologically. 2) Papanicolaou stain had no effect on the degree of shrinkage of the area and the shape of cilia or mv. 3) When the samples were transferred from ethanol to critical point drying, without immersion in isoamyl acetate, artifacts appeared in small granulated form. 4) The menopausal phase was divided into two groups which showed a shift of the maturation Index (MI) to center and had a slender mv and the other group which showed a shift to the left and granular mv. The nether surface of the cells showed a wrinkled and irregular undulations and did not show cilia or mv. 5) In adenomatous hyperplasia, the ratio of ciliated cell to no ciliated cell was four to one. It was two to one in cystic glandular hyperplasia. 6) The dense and short mv were observed in well-differentiated adenocarcinoma and poorly-differentiated adenocarcinoma showed neither mv nor cilia. Morphologic changes of mv and cilia in carcinomatous change of uterine endometrium commenced with a decrease in cilia, shifted to the shortening and disappearance disappearance of mv.

Adenocarcinoma↗
PubMed1995

Demonstration of Chlamydia trachomatis in inguinal lymphadenitis of lymphogranuloma venereum: a light microscopy, electron microscopy and polymerase chain reaction study.

Intravacuolar organisms in vacuolated macrophages were associated with areas of necrosis and suppuration in 12 patients with suppurative inguinal lymphadenitis. The intravacuolar organisms measured 0.2 to 2.0 micrometers in diameter, stained Gram negative with the Brown-Hopp's tissue Gram stain, faintly blue with hematoxylin and eosin stain, and black with the Warthin-Starry silver impregnation stain. The organisms lined vacuolar membranes and/or clumped in centers of vacuoles. Electron microscopy revealed elementary and reticulate bodies and intermediate forms characteristic of the genus Chlamydia. Cultures of three lymph nodes in McCoy cells grew Chlamydia trachomatis, lymphogranuloma venereum (LGV) serovars. Polymerase chain reaction using primers for chlamydial 16S ribosomal DNA confirmed the organisms as Chlamydia in lymph nodes from nine patients. Recognition of chlamydial organisms by light microscopy in tissue sections of lymph nodes allows a definitive diagnosis of lymphogranuloma venereum.

Adult↗
PubMed1998

Laser scanning microscopy in enzyme histochemistry. Visualization of cerium-based and dab-based primary reaction products of phosphatases, oxidases and peroxidases by reflectance and transmission laser scanning microscopy.

The reflectance mode of confocal laser scanning microscopy is suitable to detect cerium-based primary reaction products of oxidases (CeIV-perhydroxide) and phosphatases (CeIII-hydroxy-phosphate converted into CeIV-perhydroxy-phosphate) as well as of DAB-based primary reaction products (Ni-DAB, Ni-FeII-DAB and CeIV-DAB complexes) of cytochrome C oxidase and peroxidases in vibratome, cryotome and semithin plastic sections. In combination with confocal detection 3D images with submicron spatial resolution can be obtained. Moreover, CeIV-perhydroxide, CeIV-perhydroxy-phosphate, CeIV-DAB complexes and catechol-DAB polymers are highly absorptive. Among other additives, especially stable nitroxyl radicals led to a distinct improvement of the DAB staining in terms of sensitivity and proper localization. This was proven in addition by means of blotting a horseradish peroxidase dilution series during several experiments. In sections it was easily possible to record reflectance signals and high transmission contrast at the wavelength of the exciting argon ion laser (preferentially 488 nm). The results of an imbibition study of cerium-containing model precipitates indicate that the cerium generally should be oxidized prior to observation because the index of refraction of CeIV compounds is considerably higher than that of the corresponding CeIII compounds. A comparative numerical assessment of reflection intensities from reflectant parts in morphologically similar sections is possible. Confocal laser scanning microscopy offers a unique way for high resolution detection of primary histochemical reaction products being sufficiently reflective and/or absorptive. The proposed techniques may open new methodological possibilities for basic research and for medical diagnosis.

3,3'-Diaminobenzidine↗
PubMedDate not supplied

Electron microscopy of isolated human hepatocytes. (Micromethods for scanning and transmission electron microscopy).

We have investigated, by scanning and transmission electron microscopy (SEM and TEM), the cell surface morphology of isolated human hepatocytes. For this purpose, liver cells were mechanically isolated from surgical or needle liver biopsies, fixed in 3% glutaraldehyde and post-fixed in 2% osmium tetroxide. In order to handle a low number of cells, a particular procedure for harvesting hepatocytes on coverslips has been developed for SEM and an in situ embedding procedure in polyethylene-embedding capsules was applied for TEM. A rough membrane exhibiting short, uniform microvilli and pores of 0.1 mu in diameter was the main feature of isolated liver cells. Furthermore, single hepatocytes showed no polarity and junctional or bile canaliculus remnants were rarely observed. However, differences in surface configuration were noted in relation to culture conditions, such as oxygen and temperature during isolation procedures. SEM, when controlled by TEM for intracellular preservation, is proposed as a reliable method for screening small quantities of hepatocyte suspensions, for intact cells and for the study of surface configuration under experimental conditions.

Cells, Cultured↗
PubMed2005

Imaging microscopy of the middle and inner ear: Part II: MR microscopy.

Anatomic definition of the membranous labyrinth in the clinical setting remains limited despite significant technological advances in magnetic resonance imaging (MRI). Recent developments in ultra-high resolution imaging for use in the research laboratory on small animals and pathologic specimens have given rise to the field of imaging microscopy. We have delineated for the first time the labyrinthine structures in a human temporal bone cadaver specimen using these novel techniques. This approach to the study of the middle and inner ear avoids tissue destruction inherent in histological preparations using standard light microscopy techniques. Part I of this series focused on bony middle and inner ear anatomy with MicrCT. In Part II, we present high-resolution MicroMR images to highlight the utility of this technique in teaching radiologists and otolaryngologists clinically relevant anatomy focusing on the membranous labyrinth. This anatomy can be further enhanced using 3D volume-rendered images. It is hoped that familiarity with these ex vivo anatomic techniques will encourage further developments in the field of high-resolution clinical imaging for patients with temporal bone pathologies.

Anatomy, Cross-Sectional↗
PubMedDate not supplied

Combined atomic force microscopy and scanning tunneling microscopy imaging of cross-sectioned GaN light-emitting diodes.

Cross-sectional scanning tunneling microscopy (STM) was combined with atomic force microscopy (AFM) over the same area to characterize a cross-sectioned GaN light emitting diode. Because GaN is typically grown on a non-native substrate and also forms a wurtzite crystal structure, a cryogenic cleaving technique was developed to generate smooth surfaces. The depletion region surrounding the p-n junction was clearly identified using STM. Furthermore, by imaging under multiple sample biases, distinctions between the n-doped and p-doped GaN could be made.

Journal Article↗
PubMed2006

Observation of self-assembled fluorescent beads by scanning near-field optical microscopy and atomic force microscopy.

Optical response and topography of fluorescent latex beads both on flat self-assembled monolayer and on a micron-patterned surface with poly(dimethylsiloxane) are studied. Scanning near-field optical microscopy and atomic force microscopy were utilized together for detecting fluorescence and imaging topography of the patterned latex beads, respectively. As a result, the micro-patterned latex beads where a specific chemical binding occurred show a strong signal, whereas no signals are observed in the case of nonspecific binding. With fluorescein isothiocyanate (FITC), it is convenient to measure fluorescence signal from the patterned beads allowing us to monitor the small balls of fluorescent latex.

Journal Article↗
PubMed2001

Glassy cholesteric structure: thickness variation induced by electron radiation in transmission electron microscopy investigated by atomic force microscopy.

During the observation of glassy cholesteric liquid crystals in transmission electron microscopy (TEM), a new contrast is created or enhanced by electron radiation which has a direct relationship with the periodic microstructure of the specimen. In this paper, we investigate the variations of the sample thickness and mass density as possible causes of this irradiation contrast. By means of observations in atomic force microscopy (AFM) coupled to TEM, we compared the surface corrugations of non-irradiated and irradiated specimens. It is shown that the final contrast is the result of several processes. including fracture during ultramicrotomy and mass loss during irradiation. Mass loss acts as an etching, and hence results in a decrease of the sample thickness. The etching depends on the initial molecular orientation, thus evidencing the latent structure. An electron channelling mechanism is suggested to explain this behaviour.

Journal Article↗
PubMed2002

Current and potential characterization on InAs nanowires by contact-mode atomic force microscopy and Kelvin probe force microscopy.

We fabricated InAs nanowires on GaAs giant step structures, and studied their surfaces by two methods; one was current detection by contact-mode atomic force microscopy, and the other was surface potential measurement by Kelvin probe force microscopy (KFM). In the current detection method, the regions where the large current flowed were distributed along the step edges, and these regions agreed well with the expected distribution of InAs. This result confirms that the InAs nanowires were formed along the GaAs giant step edges. The KFM measurements showed that the potential value became more negative along each step edge, where the InAs nanowire was expected to be formed. The surface potential of the InAs nanowires is more negative than that of the surrounding GaAs, which may result from the electron accumulation in the InAs nanowires.

Journal Article↗
PubMed2000

Chemical force microscopy of microcontact-printed self-assembled monolayers by pulsed-force-mode atomic force microscopy

A novel chemically sensitive imaging mode based on adhesive force detection by previously developed pulsed-force-mode atomic force microscopy (PFM-AFM) is presented. PFM-AFM enables simultaneous imaging of surface topography and adhesive force between tip and sample surfaces. Since the adhesive forces are directly related to interaction between chemical functional groups on tip and sample surfaces, we combined the adhesive force mapping by PFM-AFM with chemically modified tips to accomplish imaging of a sample surface with chemical sensitivity. The adhesive force mapping by PFM-AFM both in air and pure water with CH3- and COOH-modified tips clearly discriminated the chemical functional groups on the patterned self-assembled monolayers (SAMs) consisting of COOH- and CH3-terminated regions prepared by microcontact printing (microCP). These results indicate that the adhesive force mapping by PFM-AFM can be used to image distribution of different chemical functional groups on a sample surface. The discrimination mechanism based upon adhesive forces measured by PFM-AFM was compared with that based upon friction forces measured by friction force microscopy. The former is related to observed difference in interactions between tip and sample surfaces when the different interfaces are detached, while the latter depends on difference in periodic corrugated interfacial potentials due to Pauli repulsive forces between the outermost functional groups facing each other and also difference in shear moduli of elasticities between different SAMs.

Journal Article↗
PubMed2001

Atomic Force Microscopy and Scanning Electron Microscopy Reveal Genome-dependent Ultrastructure of Seed Surface.

Both scanning electron microscopy (SEM) and contact mode imaging via atomic force microscopy (AFM) have been utilized to elucidate the ultrastructure of mung bean seed surfaces. The results indicate: 1) that AFM is useful in the examination of seed surface ultrastructure ex-vaccuo without the need for additional complex preparative procedures; and 2) that both the cotyledon and seed coat of different strains of mung beans bear specific ultrastructural details unique to each strain. To our knowledge, these are the first AFM images of seed surfaces.

Journal Article↗
PubMed1999

Comparative Study of Field Emission-Scanning Electron Microscopy and Atomic Force Microscopy to Assess Self-assembled Monolayer Coverage on Any Type of Substrate.

: In this work, we show how field emission-scanning electron microscopy (FE-SEM) can be a useful tool for the study of self-assembled monolayer systems. We have carried out a comparative study using FE-SEM and atomic force microscopy (AFM) to assess the morphology and coverage of self-assembled monolayers (SAM) on different substrates. The results show that FE-SEM images present the same qualitative information obtained by AFM images when the SAM is deposited on a smooth substrate (e.g., mica). Further experiments with rough substrates (e.g., Al grains on glass) show that FE-SEM is capable of unambiguously identifying SAMs on any type of substrate, whereas AFM has significant difficulties in identifying SAMs on rough surfaces.

Journal Article↗
PubMed2006

Plastic-to-elastic transition in aggregated emulsion networks, studied with atomic force microscopy-confocal scanning laser microscopy microrheology.

In this paper, we demonstrate how the simultaneous application of atomic force microscopy (AFM) and confocal scanning laser microscopy (CSLM) can be used to characterize the (local) rheological properties of soft condensed matter at micrometer length scales. Measurement of AFM force curves as a function of the indentation amplitude and speed (magnitude and direction) can produce a "mechanical fingerprint" that contains information about material stiffness, hysteretic losses, and time scales for stress relaxation and/or network recovery. The simultaneous CSLM visualization of changes in the material's structure provides complementary information about how the material accommodates the indentation load. Since these experiments are done on areas of O(100 microm2) on materials having a surface of O(1 cm2), the measurements can be repeated on "fresh" material many times, contrary to traditional rheometers where the whole sample is loaded at once. As a particular example, we consider the case of a network of aggregated water-in-oil (W/O) emulsion droplets, in which the mechanical behavior changes drastically over time. Whereas the freshly prepared material shows a soft plastic behavior, after a time lapse of several weeks, the very same sample shows a much stiffer and elastic response. This drastic change in behavior is clearly reflected both in the signature of the AFM force curves and in (the reversibility of) the structural deformations observed with CSLM. The fact that these drastic mechanical changes take place without significant changes in the structure of the material (before loading) indicates that the stiffening of the droplet network is caused by an increase in the strength of the bonds between droplets. A remarkable finding for the elastic droplet network is that, while the structure recovers completely after the indenter is taken out, there is still an appreciable hysteresis in the force curves, indicating that dissipation also occurs. This hysteresis was not found to depend on the indentation speed.

Journal Article↗
PubMed2002

Comparative study of a block copolymer morphology by transmission electron microscopy and scanning force microscopy.

Using transmission electron microscopy (TEM) and scanning force microscopy (SFM) together, it was possible to verify important structural features of a nanostructured bulk material such as the kp-morphology in an ABC triblock copolymer. By applying suitable imaging techniques during the SFM measurements it was possible to determine the morphology without additional manipulation steps in between. In comparison, TEM investigations on this type of material usually require selective staining procedures prior to the measurement. Also electron beam damage is often encountered during TEM measurements especially if components such as poly(methacrylates) are present. In contrast, SFM measurements can be assumed not to significantly change the phase dimensions of the components.

Journal Article↗
PubMed2005

Characterization of polymer thin films by phase-sensitive acoustic microscopy and atomic force microscopy: a comparative review.

The potential of phase-sensitive acoustic microscopy (PSAM) for characterizing polymer thin films is reviewed in comparison to atomic force microscopy (AFM). This comparison is based on results from three-dimensional vector contrast imaging and multimodal imaging using PSAM and AFM, respectively. The similarities and differences between the information that can be derived from the AFM topography and phase images, and the PSAM phase and amplitude micrographs are examined. In particular, the significance of the PSAM phase information for qualitative and quantitative characterization of the polymer films is examined for systems that generate surface waves, and those that do not. The relative merits, limitations and outlook of both techniques, individually, and as a complementary pair, are discussed.

Journal Article↗
PubMed2006

Metal particles in a ceramic matrix--scanning electron microscopy and transmission electron microscopy characterization.

This paper is concerned with ceramic matrix (Al(2)O(3)) composites with introduced metal particles (Ni, Fe). The composites were obtained via sintering of powders under very high pressure (2.5 GPa). Scanning electron microscopy and transmission electron microscopy were chosen as the tools for the identification and description of the shape, size and distribution of the metal particles. The Al(2)O(3)-Ni composite contained agglomerates of the Ni particles surrounded by ceramic grains and nanometre-size Ni particles located inside the ceramic grains and at the ceramic grain boundaries. In the Al(2)O(3)-Fe composite, the Fe particles were mostly surrounded by ceramic grains. Moreover, holes left by the Fe particles were found. The high pressure used in the fabrication of the composites changed the shape of the metal and ceramic powder grains via plastic deformation.

Journal Article↗