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At least 235 records · Page 13Linked to original sources
PubMedDate not supplied

A method of comparing spermatozoa with light and scanning electron microscopy.

A new method of comparing light microscopy and scanning electron microscopy in the study of small cells, such as spermatozoa, that must be examined under oil immersion is described. A grid is etched on the corner of a microscope glass slide, and its inner edges are incised. Its surface area is calculated as a function f the chamber of the critical-point drying apparatus. This method dispenses with the need for any special coverslip and enables the cells to be observed under oil immersion.

Cytological Techniques↗
PubMedDate not supplied

The collagenous architecture of articular cartilage. Correlation of scanning electron microscopy and polarized light microscopy observations.

The localization and directional orientation of collagen fibers in articular cartilage is demonstrated by scanning electron microscopy and polarized light microscopy. Vertical sections of articular cartilage show different directional orientations of collagen fibers through all zones of cartilage depending upon whether the sections are parallel or perpendicular to the cleft pattern produced when the surface of articular cartilage is pierced with a round pointed awl. Sections parallel to the cleft axis show a significant population of oblique collagen fibers which are not seen in sections perpendicular to the clefts. These oblique fiber groups show a progression from nearly radial to nearly tangential orientation from deep to more superficial zones, with the most abrupt directional change seen through the transitional zone. Within the transitional zone there is a narrow band having no vertical or horizontal collagen fibers and in which collagen fibers intersect predominantly at angles ranging between 45 and 135 degrees. The number of chondrocyte lacunae per unit area is greater in sections parallel to the cleft axis compared to perpendicular sections by a factor of approximately 1.6:1. There is therefore a greater relative number of chondrocytes in the plane of section having the greatest abundance of oblique collagen fibers, suggesting a cellular basis for the collagenous architecture observed. The results are consistent with published biophysical data relating tensile and swelling properties of all zones of articular cartilage to the cleft axis.

Animals↗
PubMed1994

Three-dimensional organization of biological tissues: a new method for investigation using scanning electron microscopy.

A new method is described which enables the visualization of hidden cellular surfaces of biological tissues. The method does not depend on the kind of fixative solution, the duration of the fixation, or the quantity of extracellular matrix. The samples are chemically dissociated with potassium ethoxide until the first individual cells appear in the solution. This initial process is followed by phase contrast microscopy, and remaining tissue is investigated with scanning electron microscopy. The method has proved more effective than conventional enzymatic techniques and is a simple, quick, and effective way to investigate the three-dimensional organization of different normal and pathological tissues.

Aorta↗
PubMedDate not supplied

[Comparative light and scanning electron microscopy studies of the morphologic structure of ligament insertions into the bone].

The microstructure of the osseous ligament insertion was studied by light microscopy and scanning electron microscopy using the insertion of the membrana interossea antebrachii as an example. The scanning electron microscopical findings of specimens which had been prepared by freeze-fracturing confirm the typical 4-zone-structure of the osseous ligament insertion. The findings emphasize the functional importance of both zones of unmineralized and mineralized fibrous cartilage, which represent an effective shock absorbing system for the collagenous structures of the osseous ligament insertion.

Cartilage↗
PubMedDate not supplied

Natural color scanning electron microscopy based on the frequency characteristics of the human visual system.

The principles of image formation in natural color scanning electron microscopy (NC-SEM) are discussed in detail. This method is based on the frequency characteristic of the human visual system. It is shown that the Mach effect and masking effect are important in the characteristics. The former, which can enhance structural details, is visually similar to the edge effect in secondary electron (SE) images, and the latter is required for proper representation of very degraded color information obtained from a light microscope. When using these effects suitably, an NC-SEM image with the resolution equivalent to that of an SEM image can be acquired, though it is composed of an SEM image and a special video microscopy (VM) image with a resolution much lower than the SEM image of the identical view. The NC-SEM is more effective than the SEM in observation. interpretation, and analysis of various samples with important color information.

Color↗
PubMed1989

Characterization of exposure to molds and actinomycetes in agricultural dusts by scanning electron microscopy, fluorescence microscopy and the culture method.

Air samples from 79 farms with 10(5) to 10(11) microorganisms/m3 were analyzed by scanning electron microscopy (SEM), fluorescence microscopy (FM), and the culture method. The total exposure to microorganisms (particularly actinomycetes) was underestimated when assessed as colony-forming units (cfu). The average cfu count was one-sixth of the total count according to SEM or FM, and the individual variability was great. This occurrence was partly explained by the aggregation of spores. Single spores accounted for 2-65% of all spores in 35 samples. There was an average of three spores/particle, and 93 (range 67-100)% of the spores were single or in aggregates of respirable size. Aggregation was more pronounced for actinomycetes and at high spore counts. Actinomycetes and bacteria could not be distinguished by FM. Bacteria (other than actinomycetes) were not detected by SEM, yet the total count of microorganisms was similar for FM and SEM. Most particles were spores from actinomycetes and fungi of the genera Aspergillus or Penicillium.

Actinomycetales↗
PubMed1995

An improved protocol for immunogold staining for scanning electron microscopy of cultured cells.

This paper describes an effective protocol for preparing immunogold-labelled cultured cells for high-resolution scanning electron microscopy. The cells examined were rat peripheral nerve Schwann cells and fibroblasts. The protocol employs low concentrations of chemicals and decreased fixation time. The resultant immunohistochemical cell labelling has little or no background staining, while maintaining the morphological integrity of the cell membrane.

Animals↗
PubMed1973

Identification of human B and T lymphocytes by scanning electron microscopy.

In this study a variety of human lymphocytes of known B or T cell type, obtained from multiple sources, were prepared for scanning electron microscopy (SEM) by the critical point drying method. Distinction between normal B and T lymphocytes was relatively easy in most instances, on the basis of their surface architecture. Using immunological methods, between 20 and 30% of normal peripheral blood lymphocytes (PBL) were identified as B cells and from 69 to 82% as T cells. SEM results showed that 20% of the PBL had a complex villous surface and approximately 80% of cells were smaller and had a relatively smooth surface. Comparison of the above data and enrichment of B cells from PBL, by centrifugation after T cell rosettes had formed, indicated that the "villous" cells were B lymphocytes and the "relatively smooth" cells were T lymphocytes. T cells obtained from two human thymuses were also of the generally smooth cell type. Further evidence for the distinction of B and T lymphocytes, on the basis of surface morphology, was obtained from the examination of cultured lymphoid cell lines of known B or T cell derivation. Cells from cases of chronic lymphocytic leukemia also provided support for the above interpretations. Five of six untreated cases were clearly of B cell type by immunologic and SEM criteria. One unusual case showed the presence of T and B lymphocytes in almost equal numbers by SEM and a mixture of B and T cells by immunologic markers. An additional case that had received chemotherapy showed numerous atypical cells that were difficult to classify by SEM. Detailed examination of the smoother T cells showed that at least half of them had a moderate number of surface digitations and a small proportion had an intermediate surface morphology with a relatively large number of surface digitations. The latter presented difficulties in classification and may correspond to different stages of differentiation and represent subpopulations of lymphocytes. The distinction between human B and T lymphocytes on the basis of their surface architecture can be made by SEM of critical point dried samples, with relative ease in most but not all instances. The effects of stimulation, cell cycle, differentiation, intercellular contact, and density of cell population, on the surface architecture of lymphoid cells, remain to be determined.

B-Lymphocytes↗
PubMed2005

Characterization of a peg-like terminal NOR structure with light microscopy and high-resolution scanning electron microscopy.

An atypical peg-like terminal constriction ("peg") on metaphase chromosomes of the plant genus Oziroë could be identified as a nucleolus organizing region (NOR) by detecting 45S rDNA with correlative light microscopy (LM) and scanning electron microscopy (SEM) in situ hybridization (ISH). Using high-resolution 3D analytical SEM, the architecture and DNA distribution of the peg-like NOR were characterized as typical for chromosomes, albeit with significantly smaller chromomeres. ISH procedure was improved for SEM concerning signal localization, labeling efficiency, and structural preservation, allowing 3D SEM analysis of the peg-like NOR structure and rDNA distribution for the first time. It could be shown that implementation of FluoroNanogold markers is an attractive tool that allows efficient immunodection in both LM and SEM. A model is proposed for the peg structure and its mode of condensation.

Cell Cycle↗
PubMed1989

Visual detection of microencapsulated insecticides with selective staining and scanning electron microscopy.

Selective staining with Sudan IV and methylene blue for light microscopy and scanning electron microscopy (SEM) were investigated to determine their potential for detecting and quantifying microencapsulated insecticides. Penncap-M (microencapsulated methyl parathion), Penncapthrin (microencapsulated permethrin), and Dyfonate (microencapsulated fonofos) were selectively stained with Sudan IV but not with methylene blue. Selective staining was not possible for Altosid SF-10 or SR-20 (microencapsulated methoprene) with either stain. Sudan IV enabled detection of some microencapsulated formulations in the digestive content of selected aquatic invertebrates and prepared contaminated pollen samples. Staining intensity with Sudan IV was greatest with acetone but capsular damage was high. A solvent ratio of 50:50 and 20:80 acetone/xylene minimized capsular collapse and maintained good staining intensity. The use of SEM for capsule identification and quantification depended upon the method of sample preparation: the slide smear method was superior to samples prepared by incision or microtomy. SEM was most suitable for investigation of formulations such as methoprene, for which selective staining was not possible. The chemical basis of staining with Sudan IV and potential application of both identification techniques are discussed.

Aedes↗
PubMed2002

[Description of eggs and nymphs of Triatoma jurbergi Carcavallo, Galvão & Lent, 1998 through optical and scanning electron microscopy].

Eggs and nymphs of Triatoma jurbergi were described using optical microscopy and scanning electron microscopy. T. jurbergi is a wild species, found in State of Mato Grosso (15oS and 300 m.a.s.l), Brazil. Eggs showed the operculum and surface with pentagonal and hexagonal cells, with small fractures and punctuations randomly distributed. Differences were found in the five nymphal stages of T. jurbergi, that allow their to be distinguished from the similar species T. guazu. The diagnostic characters most useful for differentiation were the general color of the insect, abdomen shape and its length.

Animals↗
PubMed1976

[Leukocyte and erythrocyte interaction with collagen in vitro: scanning electron microscopy study].

Scanning microscopic investigations show the interaction of Leukocytes and Erythrocytes with fibrillar and aggregating type I and type III collagens in vitro. Leukocytes, in the presence of collagen, form loose aggregates within a minute and these aggregates, after 15 to 30 minutes, coalesce and become compact. The close association of the fibrillar collagens to the leukocyte surfaces is shown. Fibrillar collagen and collagen in solution with erythrocytes form only loose aggregates. Qualitative differences between the various collagen preparations were not found. The pathogenetic implications of these observations are briefly discussed.

Blood Platelets↗
PubMed1988

Preparation of cultured mammalian cells for transmission and scanning electron microscopy using Aclar film.

Common methods for the preparation of cultured cells for concurrent light microscopy (LM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) are not completely satisfactory. This article describes how we grow mammalian cells on plastic disks made from Aclar film. Aclar is a transparent fluorinated-chlorinated thermoplastic that contains no volatile components and is, for all practical purposes, chemically inert. Cells adhere to it readily and remain attached after fixation, dehydration, and critical-point drying or embedding. The film also accepts heavy metal coating by ionic bombardment and is extremely stable in the vacuum of the SEM. LM observations are unhindered by Aclar, since the film is as transparent as glass. Fluorescence microscopy is possible with this film, since it exhibits no detectable autofluorescence. During SEM observation, the film has great dimensional stability, and the cells and heavy metal coating remain attached to the Aclar even under high-resolution operating conditions. TEM processing of specimens grown on Aclar is simplified by the fact that Aclar does not stick to the epoxy resins used in EM. Furthermore, Aclar is easily sectioned and does not damage knives used in ultramicrotomy. The use of Aclar film considerably simplifies the preparation of cultured cells for all types of microscopy. This method is particularly useful in correlating surface features between SEM and TEM observations.

Animals↗
PubMed1995

Improved methods for preserving macromolecular structures and visualizing them by fluorescence and scanning electron microscopy.

To determine the optimal procedures to preserve cytoskeletal and other macromolecular structures for microscopic studies we have evaluated the effects of various methods to extract cultured cells. In this report, we compare results using different fixatives, crosslinking reagents, and permeabilization methods on (1) the labeling of cells for fluorescence microscopy with phalloidin or antibody against tubulin; and (2) the morphological preservation of macromolecular structures for scanning electron microscopy. Maximal labeling of F-actin with phalloidin was obtained by fixing cells in 4% paraformaldehyde (PFA) and labeling the unextracted cells with methanolic phalloidin, whereas maximal labeling of tubulin required prefixation with either PFA or the bifunctional protein crosslinking reagent, dithiobis (succinimidylpropionate) (DSP) and extraction with ethanol or Triton in a high salt buffer. However, for both qualitative and quantitative light and electron microscopic studies of intracellular macromolecular structures, prefixation with DSP and extracting with Triton X-100 in a stabilizing buffer is the overall method of choice for both labeling and morphological studies. Although other methods provide maximal labeling or preservation of specific structures, this method provides excellent preservation of morphological structure while allowing proteins to be preserved and labeled by specific probes.

Actins↗
PubMed1990

Different phenotypes of cultured microvessel endothelial cells obtained from bovine corpus luteum. Study by light microscopy and by scanning electron microscopy (SEM).

Morphological heterogeneity has not been documented for cultured endothelial cells isolated from the microvascular bed of any organ. As the corpus luteum depends on a rich microvascularization, endothelial cells were dislodged from developing corpora lutea by mechanical dissection followed either by collagenase digestion or by no digestion. Cell separation was carried out by Percoll density centrifugation. Although the yield of intact cells was higher with collagenase treatment than without, successful endothelial cell cultures were only established when cells remained untreated. Viewed by light microscopy after an average lag phase of 10 days, five different phenotypes of endothelial cells were found under similar simple culture conditions: isomorphic epithelioid, polymorphic epithelioid, spindle-shaped, round, and phase-dense phenotypes. Monolayers appeared within 2-4 weeks. After an additional period of 2-4 weeks, tubular forms with a specific pattern were noted for types 1-3, the so-called pseudotubular forms for type 4, and none for type 5. Cell types differed in their cytochemical and immunocytochemical responses. Examined by SEM, type 1 displayed a more conspicuous surface anatomy than type 2. Types 3-5 demonstrated striking cell processes that were characteristic of each type. Tubular forms of types 1 and 2 showed cell borders and a marked increase in surface specializations, whereas tubular forms of type 3 lacked detectable cell borders in the absence of a striking surface anatomy. Pseudotubular forms of type 4 developed no particular spatial organization. Thus, for the first time, morphological evidence is provided that different endothelial cell types are obtained from diverse segments of the microvascular bed.

Acid Phosphatase↗