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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992), S. 130-150 
    ISSN: 1059-910X
    Keywords: Electron microscopy ; Scanning electron microscopy ; High resolution ; Cytoskeleton ; Biological specimen preparation ; Cultured cells ; Electrophoresis ; Bifunctional crosslinking reagents ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Today's electron microscopes have a resolution sufficient to resolve supramolecular structures. However, the methods used to prepare biological samples for electron microscopy often limit our ability to achieve the resolution that is theoretically possible. We use whole mounts of detergent-extracted cells grown on Formvar-coated gold grids as a model system to evaluate various steps in the preparation of biological samples for high resolution scanning electron microscopy (SEM)Factors that are important in determining the structure and composition of detergent-extracted cells include the nature of the detergent and the composition of the extraction vehicle. Chelation of calcium is extremely important to stabilize and preserve the cytoskeletal filaments. We have also demonstrated both morphologically and by gel electrophoresis that treatment of cells with bifunctional protein crosslinkers before or during extraction with detergent can significantly enhance the preservation of both proteins and supramolecular structures.The methods used to dry samples are a major determinant of the quality of structural preservation. For cytoskeletons freeze-drying (FD) is superior to critical point-drying (CPD), one reason being that CPD samples have to be dehydrated, thereby causing more shrinkage as compared to FD samples. The high pressures to which samples are exposed during CPD may also cause increased shrinkage, and water contamination during CPD causes severe structural damage. We have obtained the best structural preservation of detergent-extracted and fixed cells by manually plunging them into liquid propane and drying over night in a freeze-drayer.The factor that most limits achievement of high resolution in SEM is the metal coat, which has to be very thin, uniform, and free of grain in order not to hide structures or to create artifactual ones. We have found that sputter-coating with 1-3 nm of tungsten (W) or niobium )Nb( gives extremely fine-grained films as well as satisfactory emission of secondary electrons. These samples can also be examined at high resolution by transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). The best preservation and visualization of supramolecular structures have been obtained using cryosputtering, in which the samples are freeze-dried and then sputter-coated within the freeze-dryer while still frozen. © 1992 Wiley-Liss, Inc.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 23 (1992), S. 225-229 
    ISSN: 1059-910X
    Keywords: Scanning electron microscopy ; Ultrastructure ; Zona pellucida ; Mucus ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The fine structure of the zona pellucida (ZP) covering the oocyte and of the mucus covering the surface of the intestinal villi was investigated by using a new method employing ruthenium red (RR), saponin, and osmium-thiocarbohydrazide impregnation.The glycoproteic matrices both appeared constituted by thin filaments (ranging from 22 to 50 nm in thickness) anastomosed to form a very fine network.RR prevented the dissolution and/or alteration of glycoproteins and polyanionic carbohydrates induced by acqueous fixatives. Saponin was a detergent of the soluble proteins. Osmium-thiocarbohydrazide preserved the glycoproteic matrix filaments from the mechanical stress induced by dehydration and critical point drying and reduced filaments packing and shrinkage. The technical improvement was demonstrated by the following results: 1) a regular arrangement of the filaments network; 2) a thickness of mucus filaments smaller than that obtained with other methods of preparation; 3) a homogeneous thickness of ZP filaments.This method allowed a very detailed study of the fine structural organization of the ZP and intestinal mucus. Therefore, this technique can be useful for a better evaluation of the morphodynamic of these and other glycoproteic matrices. © 1992 Wiley-Liss, Inc.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 27 (1994), S. 429-438 
    ISSN: 1059-910X
    Keywords: Biological pattern formation ; Cuticle ; Thin-film ; Lattice ; Scanning electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: All butterfly and moth scales and bristles are made of non-living insect cuticle. Each is the product of a single epithelial cell, and all share the same basic architecture. However, some are highly specialized, and their cuticle is further elaborated into stacks of thin-films, lattices, or other minute structures, many of which first came to our attention because they interact, with light to produce structural colors. The scale cell forms the scale by extruding a projection of itself and secreting around it the outer epicuticle, a thin cuticular envelope which will form the outermost layer of the scale. The inner layers of cuticle, collectively called the procuticle, are secreted thereafter and go on to form the lattices, pillars, or other internal structures of the scale. We believe that the pattern-forming mechanisms used by the cell to shape the cuticle into its finished form include elastic buckling of the outer epicuticle to produce external folds, and “masking” of certain areas of the original epicuticular envelope to produce thin spots which will break through to become windows. Varied though they be, all insect cuticular patterns have common basic elements, which suggests that our findings may be generalized to other highly patterned insect cuticles, particularly those formed by single cells. © 1994 Wiley-Liss, Inc.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 27 (1994), S. 25-45 
    ISSN: 1059-910X
    Keywords: Transmission electron microscopy ; Scanning electron microscopy ; Histochemistry ; Cytokeratins ; Microfilaments ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: In salivary glands and other exocrine organs, there are starfish-shaped cells that lie between the basal lamina and the acinar and ductal cells. These have structural features of both epithelium and smooth muscle cells, and so are called myoepithelial cells. Their functions include contraction when the gland is stimulated to secrete, compressing or reinforcing the underlying parenchymal cells, thus aiding in the expulsion of saliva and preventing damage to the other cells. They also may aid in the propagation of secretory and other stimuli. Their common developmental origin with the basal cells of the larger ducts is displayed in the mature glands by shared structural and immunohistochemical features, but most such basal cells do not have the distinguishing features of myoepithelial cells, such as myofibrils. Although myoepithelial cells can be identified by light microscopy through enzyme histochemistry and special stains and immunohistochemistry for their myofibrils, these techniques can be misleading in salivary gland neoplasms. Thus, the most reliable means of identifying neoplastic myoepithelial cells is with a combination of histochemistry and electron microscopy. The extent to which these cells are derived from undifferentiated stem cells in both normal and neoplastic growth is controversial. The presentation here of transmission electron microscopy (TEM) of well-differentiated myoepithelial cells in mitotic division indicates that stem cells are not necessarily the only source of myoepithelial cells in the later stages of salivary gland development or in neoplasia. © 1994 Wiley-Liss, Inc.This article is a US Government work and, as such, is in the public domain in the United States of America.
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  • 5
    ISSN: 1059-910X
    Keywords: B Lymphocytes ; AIDS ; HIV ; Immunodeficiency ; Scanning electron microscopy ; SIV ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The ultrastructural features of AA-2 cells infected with either of two strains of simian immunodeficiency virus (SIVMne-E11S or SIVSMM-PBj) were examined by scanning electron microscopy (SEM). Transformed CD4+ human B lymphocytes (AA-2) were inoculated with SIV and observed at 2, 4, and 7 days post-inoculation (dPI). Infected AA-2 cells were distinguished by the progressive loss of microvilli, and variable numbers of free or protruding spherical particles measuring 90-120nm in diameter along the cell surface. Syncytial cell formation (complexes of fused cells) and necrotic cells were evident at each time point with the most numerous observations at 7 dPI. While the distribution and severity of the viral induced changes increased with time and affected virtually all cells by 7 dPI, the alterations were detected sooner and were more pronounced in SIVSMM-PBj infected cells. This finding is consistent with the in vivo data from primate studies using the same strains of SIV. Syncytial cells exhibited slight to moderate indentations which appeared to coincide with the boundaries of individual cells forming the complex. The plasma membrane of syncytial cells was relatively smooth and lacked microvilli. Spherical particles and buds protruding from the plasma membrane were predominate features of syncytial cell surfaces. By the employment of antisera generated against whole SIVMne-E11S, both transmission and scanning immunoelectron microscopy confirmed the identity of the spherical structures as free and budding SIV virions. © 1994 Wiley-Liss, Inc.
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  • 6
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 32 (1995), S. 357-361 
    ISSN: 1059-910X
    Keywords: Scanning electron microscopy ; Human neutrophils ; Tissue preparation ; Surface morphology ; Cell volume ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Using human leukocytes as test specimens, three different drying procedures for scanning electron microscopy: critical-point drying (CPD), Peldri II, and tetramethylsilane (TMS), were compared. All three procedures produced identical surface morphology preservation. An equal amount of volume shrinkage was observed regardless of the dehydrants and drying techniques employed. Considering the simplicity, convenience, and time saved, air-drying with TMS is by far the best choice for preparing animal cells for scanning electron microscopy. © 1995 Wiley-Liss, Inc.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 30 (1995), S. 491-495 
    ISSN: 1059-910X
    Keywords: Heart ; “Section directed” cryosectioning ; Scanning electron microscopy ; Immunohistochemistry ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A new method to study the developing heart was developed. Using this “section directed” cryosectioning method, appropriate fixed embryos can be trimmed optimally to obtain sectional planes that, if necessary, can be matched with histologically treated sections. As a result, the morphological information obtained with the scanning electron microscope can be compared in detail with the information on the molecular phenotypes of the subpopulations of cells as deducted from staining patterns of the sections. This method allows combination of the specific advantages of sophisticated histological techniques, such as immunohistochemistry and in situ hybridisation, with those of the scanning electron microscope. © 1995 Wiley-Liss, Inc.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 32 (1995), S. 330-336 
    ISSN: 1059-910X
    Keywords: Scanning electron microscopy ; Teaching ; Computer ; Network ; Remote control ; Ethernet ; Internet ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A laboratory designed for teaching the operation of a scanning electron microscope (SEM) has been developed. The laboratory makes use of a computer network to allow remote operation of the SEM. Movable teaching stations, consisting of a computer, TV monitor, and joystick control, enable students to view the image on the SEM screen, move the sample, control the basic operating parameters of the microscope, and acquire X-ray spectra. Images can also be stored on the computers for image analysis or incorporation into reports. The great advantage of the system is that it has been designed to be flexible enough to allow operation from any location that has access to the Internet. The system is relatively inexpensive and uses nonproprietary computer technology available at any computer store. While the laboratory has been designed for teaching, the concept of a multiuser SEM facility that is inexpensive and easy to install should have applications in both industrial and research settings. © 1995 Wiley-Liss, Inc.
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  • 9
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 4 (1986), S. 371-379 
    ISSN: 0741-0581
    Keywords: Scanning electron microscopy ; Low temperature ; Microanalysis ; Duodenum ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Low temperature scanning electron microscopy of mammalian tissue allows microanalysis data and morphological results to be considered together, without the risk of elemental diffusion introduced by liquid fixatives and processing agents. The technique, however, is time consuming and there are many areas where errors are possible and standardization of technique is advisable. The present paper describes some of the problems inherent in handling frozen tissue and comparison is made between microanalytical measurements from luminal contents and those from villous epithelium.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 5 (1987), S. 159-169 
    ISSN: 0741-0581
    Keywords: Monolayer cells ; Microcarrier beads ; Transmission electron microscopy ; Scanning electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Cross-linked dextran beads provide an excellent surface for tissue-cultured cell monolayers, and can be processed for transmission (TEM) and scanning (SEM) electron microscopy, as well as light microscopy (LM). Cells are grown to confluency on the surface of the microcarriers, where at any point aliquots can be removed and experimentally treated as desired (e.g. immunocytochemistry) providing a representative sample. Sample preparation for TEM follows standard procedures for any cell monolayer, but infiltration times must be at least doubled to allow penetration of the beads. The polymerized blocks can then be sectioned for TEM or LM with no additional steps required. SEM sample preparation involves attaching the fixed bead/cell suspension to a glass coverslip with poly-1-lysine, dehydration, critical point drying, and coating for conductivity. The fixed and dried sample can also be attached directly to the SEM stub as free beads and subsequently gold coated. These beads provide (1) an increased surface area of cells visible per area of thin section, (2) eliminates the careful orientation required for flat substrate methods of embedding, (3) decreases the amount of sample manipulation in the forms of re-embedding and gluing, and (4) decreases the amount of drying artifact seen as cracking in SEM monolayer preparations.
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  • 11
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 1 (1984), S. 331-340 
    ISSN: 0741-0581
    Keywords: Digital image processing ; Laplacin filter ; Scanning electron microscopy ; High-resolution ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Certain digital image-processing methods, which are useful for nonperiodic structural images, have been applied to high-resolution SEM images for the improvement of resolution. Samples utilized in the present study consisted of magnetic tape coated with gold, T4 phage coated with gold-palladium, and uncoated specimens of Prolamellar body (PLB) in Cucurbita moschata. These images were blurred and otherwise disturbed by electronic noise, though the images were taken at the limit of efficiency of intrinsic instrument. The major image-processing tool was the Laplacian filter, which subtracts the Laplacian from the original image. Noise, which is a serious problem in digital processing of high-resolution SEM images, was suppressed by the nonlinear type smoothing method. Also, the noise was evaluated by an autocorrelation function and a power spectrum of the image. By using these methods of “deblurring” and noise removal, we achieved better resolution, and structural details of our biological specimens were revealed.
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  • 12
    ISSN: 0741-0581
    Keywords: Bacterial identification ; Light microscopy ; Scanning electron microscopy ; Transmission electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A method for bacterial identification has been developed by means of studying the same histological sections through several types of microscopy. With this method, one section was processed and analyzed respectively for light microscopy (LM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Sections of gingival biopsies were Gram stained and bacteria tentatively identified by LM. Photographs of the sections were taken and presketched transparent acetate sheets (PTAS) were made from the photos. The same section was later prepared for SEM, areas previously thought to contain bacteria were localized by placing the PTAS onto the SEM monitoring screen. The SEM specimens were subsequently processed for TEM, bacteria were located, and micrographs obtained. The results showed that out of ten diseased gingival biopsies observed under the LM, bacteria were found to be present in all the specimens and were identified as both Gram positive and Gram negative. By transferring the section from LM to SEM, the bacteria could be relocated and their morphotype (cocci, rods, etc.) clearly identified in most of the cases. Since cocci may resemble other biological granular structures under SEM, they require further analysis under TEM for additional positive identification. This study demonstrated that the method described here is a useful tool for assessing the presence and identifying bacteria within the gingival tissues.
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  • 13
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 10 (1988), S. 15-26 
    ISSN: 0741-0581
    Keywords: Scanning electron microscopy ; Ocular microvasculature ; Microcorrosion cast ; Injection replica ; Batson's ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: We have refined the technique of vascular corrosion casting with methacrylate to permit the reproduction of physiological states of vascular tone and to produce sturdy castings of ocular microvasculature. The method entails careful maintenance of homeostasis up to the moment of plastic perfusion, avoidance of vascular rinsing or fixation with the attendant anoxia, reduction of the viscosity of the casting resin without impairing the properties of the resultant polymer, addition of a cross-linking agent to increase the strength of the plastic, and injection at physiological temperature and pressure. This casting regimen reproduces the normal anatomical conditions of blood vessels and can be used to demonstrate altered conditions of vascular tone. In all instances, the second, untouched eye serves as a control for unilateral manipulations. Special problems of replicating the ocular vasculature are related to the intraocular pressure, which opposes the vascular perfusion pressure and constitutes an impediment to perfusion.
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  • 14
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    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 15 (1990), S. 245-260 
    ISSN: 0741-0581
    Keywords: Stereocilia ; Postmortem cochlea ; Scanning electron microscopy ; Human ; Guinea pig ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The morphology of hair bundles has been studied by high resolution scanning electron microscopy using a variety of fixatives, including glutaraldehyde, glutaraldehyde-picrate, glutaraldehyde-tannic acid, glutaraldehyde followed by post-fixation in osmium tetroxide, and the osmium thiocarbohydrazide technique. Critical evaluation of several metal coatings, gold, gold-palladium, and platinum has been carried out.Both the surface texture of stereocilia and their cross-links are sensitive to fixation and metal coating. We are of the opinion that glutaraldehyde gives the best general quality of fixation and preservation for all types of cross-links. We have described three major sets of cross-links: first, lateral links connecting stereocilia within the same row; second, lateral links connecting stereocilia of adjacent rows; and third, upward-pointing links, one per stereocilium, connecting the tip of each shorter stereocilium to the lateral surface of the adjacent taller stereocilium. Current physiological and anatomical evidence suggests that the lateral links couple the individual stereocilia within the hair bundle so that they function as a single mechanical unit. The upward-pointing tip links are ideally placed to respond to mechanical deformation of the hair bundle, being stretched when the stereocilia are deflected in the excitatory direction towards the tallest row and relaxed when deflected in the opposite, inhibitory direction.Postmortem morphological changes are detected within 15 minutes of cardiac arrest and become progressively more pronounced in time. These results enabled us to distinguish specific druginduced changes which could not be attributed simply to cell death. Effects of cisplatin and kanamycin upon hair bundles are described. The work reported here is based on studies using the guinea pig cochlea. Some of the postmortem changes described have also been confirmed in human cochleas.It is stressed that many of the postmortem and drug-induced effects can only reliably be studied by high resolution scanning electron microscopy coupled with appropriate prearation procedures.
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  • 15
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    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985), S. 403-404 
    ISSN: 0741-0581
    Keywords: Endothelial cells ; Fibrinogen ; Scanning electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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  • 16
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    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985), S. 489-495 
    ISSN: 0741-0581
    Keywords: Embedment media ; Coagulant and noncoagulant fixatives ; Intracellular surfaces ; Scanning electron microscopy ; Thick sections ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Conventional plant histological specimens fixed in formalin-acetic acid-alcohol, chromic acid-acetic acid-formaldehyde, or glutaraldehyde-osmium and embedded in either paraffin or plastic are examined as possible rapid methods for providing an alternative image of cellular structure by using scanning electron microscopy. Using the mitotic figures of actively growing onion root tips as a study specimen, the organization of the nucleus and spindle apparatus is reasonably well preserved as compared with isolated mitotic spindles and studies of mitosis in endosperm tissue. Relief of internal structure in this technique is obtained through the coagulant nature of the fixative. Used judiciously, this technique can reveal aspects of the three-dimensional nature of internal tissue structure that may otherwise be difficult to discern.
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  • 17
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    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 3 (1986), S. 407-411 
    ISSN: 0741-0581
    Keywords: Mucus removal ; Nasal epithelium ; Rat ; Scanning electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The surface layer of mucus, which obscures the epithelium from view, is a major obstacle when performing scanning electron microscopic studies of the nasal mucosa. Samples treated with a 1% mixed glycosidase solution for 1 or 2 minutes, followed by agitation, removed most of the mucus from the conchae without damaging the underlying epithelium. Removal of mucus allows the complete evaluation of the underlying epithelium in normal animals and the localization and characterization of lesions in animals exposed to nasal toxicants.
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  • 18
    ISSN: 0741-0581
    Keywords: Glomerular capillary endothelium ; Vascular perfusion ; Freeze-cracking ; Scanning electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Modern morphological investigation requires the use of a variety of technological approaches and the employment of rigorous morphometric analysis for an adequate evaluation of the structural and ultrastructural features of a tissue or organ. The introduction of the technique of freeze-cracking of tissue to expose new surfaces has made it possible to quantitate the normal surface characteristics of the glomerular capillaries of the mammalian kidney. This report describes the techniques used for the preparation and quantitative assessment of normal glomerular endothelial morphology. The techniques of in vivo and in vitro vascular perfusion of kidneys as a method of fixation and the freeze-cracking of tissue are outlined in detail. In addition, a morphometric analysis of the endothelial surface characteristics are described and values are reported for the control rat and human kidneys from transplant donors.
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  • 19
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    Journal of Electron Microscopy Technique 2 (1985), S. 279-280 
    ISSN: 0741-0581
    Keywords: Endothelial cells ; Fibrinogen ; Scanning electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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  • 20
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    Journal of Electron Microscopy Technique 5 (1987), S. 65-74 
    ISSN: 0741-0581
    Keywords: Scanning electron microscopy ; Low temperature ; Microanalysis ; Duodenum ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Microanalysis data obtained using low temperature scanning electron microscopy of frozen hydrated etched mouse duodenum gives information about peak/background ratios of various elements in different cellular compartments. The present paper describes ways in which the data can be analyzed to minimize artifactual variations and to make clear where there are genuine differences in peak/background ratios when readings from different animals are compared. Using these methods, it is shown that in some areas of villous epithelium there are measurable differences in the ratios of sodium, calcium, and sulphur.
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  • 21
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    Journal of Electron Microscopy Technique 9 (1988), S. 187-208 
    ISSN: 0741-0581
    Keywords: Transmission electron microscopy ; Scanning electron microscopy ; Morphometry ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The relationship between structure and function in the distal tubule and collecting duct has been studied with morphologic and physiologic techniques, including morphometric analysis, to identify functionally distinct cell populations. The distal tubule, including the thick ascending limb (TAL) and the distal convoluted tubule (DCT), is involved in active reabsorption of sodium chloride. It is characterized by extensive invaginations of the basolateral plasma membrane, numerous mitochondria, and high Na-K-ATPase activity, features characteristic for an epithelium involved in active transport. Between the distal tubule and the collecting duct is a transition region, the connecting segment or the connecting tubule (CNT), which exhibits species differences with respect to both structure and function. The collecting duct includes the cortical (CCD), the outer medullary (OMCD), and the inner medullary (IMCD) collecting ducts. Principal cells are present throughout the collecting duct, whereas intercalated cells are located mainly in the CCD and OMCD. Morphometric analysis combined with micropuncture and microperfusion studies has provided evidence that the CNT and principal cells are responsible for potassium secretion in the connecting segment and the CCD. The OMCD is a main site of hydrogen ion secretion, and morphometric studies have provided evidence that the intercalated cells in this segment secrete hydrogen ion at least in the rat. Two configurations of intercalated cells exist in the CCD - a type A and a type B. The A cells are similar in ultrastructure to the intercalated cells in the OMCD and are believed to be involved in hydrogen ion secretion. The function of the B cells remains to be established. The inner two-thirds of the IMCD corresponds to the papillary collecting duct, which has a high permeability to urea. The relationship between structure and function in the IMCD has not been studied in detail. This review emphasizes the role of morphometric analysis in establishing the relationship between structure and function in the distal nephron.
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  • 22
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    Journal of Electron Microscopy Technique 11 (1989), S. 117-125 
    ISSN: 0741-0581
    Keywords: Scanning electron microscopy ; Peldri II drying ; Critical point drying ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A new chemical, Peldri II, is evaluated as a compound for drying soft biological tissues for scanning electron microscopy. Peldri II, a fluorocarbon, is a solid at room temperature and is a liquid above 25°C. Cells or tissues are embedded in Peldri II by immersing them in the liquid form and allowing it to solidify. Once solidified, Peldri II will sublime with or without vacuum to dry tissues, probably without introducing surface tension. Several types of cells and tissues have been examined to compare preservation with Peldri II and critical point drying techniques. No differences were detected between the two techniques when normal surface structures were examined. Peldri II appears to be a significant improvement over hexamethyldisilazane as a drying agent for scanning electron microscopy. It is also very convenient for drying large numbers of samples.
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  • 23
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    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 18 (1991), S. 106-116 
    ISSN: 0741-0581
    Keywords: Cell monolayers ; Scanning electron microscopy ; Cell morphology ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The ultrastructural characteristics of several growth matrices were examined using two cell types chosen for their distinct growth habits. Chinese hamster ovary cells and Balb-c 3T3 mouse fibroblasts were grown on flat substrates (glass, tissue culture plastic, Millipore filters) as well as spherical (glass, tissue culture plastic, cross-linked dextran) substrates. Cells were plated maintaining equal densities and growth surface area. Once the majority of the cells reached confluency, the cell's morphology on each matrix was examined using scanning electron microscopy. Digital analysis was performed on cell attachment area to compare the effect of each matrix on cell spreading.Variation in cell shape was dramatic between matrices, being most noticeable between a textured surface (filter, dextran bead) and that of a smooth (glass) surface. Even within smooth surfaces, some variation was observed. There was also an effect of matrix curvature on cell attachment area, the greatest being in the 3T3-c Balb cells, causing an overall decrease in the area of attachment between cell and matrix. The changes seen could also be related to the particular cell type used. Hamster ovary cells tended to be cylindrical and showed little effect between matrices, whereas the mouse fibroblasts, which are more flattened, showed the matrix effect to a greater degree.This study demonstrates the necessity of being aware of substrate-induced cell changes in tissue culture, where some variation in cell shape may be due to the surface on which the cells are grown as opposed to the experimental procedure.
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  • 24
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    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 14 (1990), S. 1-5 
    ISSN: 0741-0581
    Keywords: Scanning electron microscopy ; Microanalysis ; Elemental mapping ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A technique was developed to prepare archaeological fiber cross sections for electron microscopic examination and x-ray analysis. Use of this new method allows chemical and morphological information to be obtained from the interior of a single fiber or yarn. Fibers are fractured while frozen and then freeze dried. Following mounting and carbon coating, fibers are examined by scanning and backscatter electron microscopy and then analyzed by using energydispersive spectrometry. Elemental distribution is mapped by using image-processing software. In this report, the described technique is employed in the examination of ancient fibers from three different long-term storage environments (moist buried, dry buried, museum stored). Data obtained by examining the interior of fibers such as these provide insight into the conditions of a fiber's growth, the treatments applied during the fiber's processing and use, and the conditions in which the fiber was stored.
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  • 25
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    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 1 (1984), S. 341-348 
    ISSN: 0741-0581
    Keywords: Vascular casts ; Scanning electron microscopy ; Vascular anatomy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Corrosion casts provide three dimensional replicas that can be examined readily by scanning electron microscopy (SEM). They are prepared by filling vascular networks with polymerizing plastic and then digesting away the tissue. As based on our studies of ocular vessels, this report describes the vascular anatomy, as well as the artifacts, that are encountered during SEM studies of such preparations.
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  • 26
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    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 8 (1988), S. 185-191 
    ISSN: 0741-0581
    Keywords: Histologic techniques ; Scanning electron microscopy ; Blood vessels ; Pulmonary circulation ; Microcirculation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Although techniques for preparing specimens for light and electron microscopy are well established, few studies have sought to establish methods for corrosion casting of the microscopic vessels of the lung. The effects of two concentrations of glutaraldehyde, formaldehyde, and no fixative (saline control) on the filling and structure of the microvascular casts of the lung were studied. All fixatives were infused 5 minutes before casting.Formaldehyde's fixation effects were intermediate between those of glutaraldehyde and no fixation. Leakage of casting material was increased in the animals that were fixed less. Digestion time was prolonged and more undigested tissue was found in the group receiving the concentrated glutaraldehyde, although the difference in neither of these features alone reached statistical significance. Circumferential bands occurred more frequently in the large vessel casts of the less fixed animals, which may account for the less filling microvasculature in these lungs. However, good quality casts were obtained with each method.
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  • 27
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    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 5 (1987), S. 263-273 
    ISSN: 0741-0581
    Keywords: Immunocytochemistry ; Cell culture ; Cytoskeleton ; Scanning electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: This technique permits the visualization of microtubules in situ by employing silver-enhanced immunogold labeling and backscattered electron imagery. For best results, monolayer cultures of PtK2 cells are lysed with Triton X-100 in a microtubule stabilizing buffer, fixed with 1% glutaraldehyde, reduced with NaBH4, incubated with monoclonal antitubulin and 5-nm gold-labeled anti-IgG, silver enhanced, freeze dried, lightly coated with aluminum, and examined in an SEM equipped with a backscattered electron detector. A high contrast view of the entire microtubule complex of each cell is obtained. Microtubules in freeze-dried preparations have relatively smooth surfaces, whereas those in critical point dried preparations are more irregular or beaded. At high magnifications, an unstained inner core of each microtubule can be resolved. Backscattered electron imaging appears to be a promising technique for localizing cytoskeletal proteins and other intracellular antigens that can be labeled with immunogold and enhanced with silver.
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  • 28
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    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 6 (1987), S. 31-34 
    ISSN: 0741-0581
    Keywords: Scanning electron microscopy ; Recording SEM images ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Described here is the construction of two 35-mm camera adaptors for attachment to the recording monitors of scanning electron microscopes (SEM). The designs are simple and readily adaptable to almost any SEM. The choice of this camera format for recording SEM images is one of convenience as well as economy and does not sacrifice micrograph quality.
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  • 29
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    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 14 (1990), S. 367-372 
    ISSN: 0741-0581
    Keywords: Scanning electron microscopy ; Basement membranes ; Colonic development ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: We have used two epithelial-stripping techniques in our studies of the basal lamina in the developing rat colon. The first involves prolonged osmication followed by sonication; the second uses chelation of calcium by EDTA followed by sonication. Both techniques remove the epithelium from the basal lamina; however, the EDTA/sonication technique appears to produce a cleaner adepithelial surface of the basal lamina. In addition, the fine structure of the basal lamina appears to be better preserved in specimens prepared by the EDTA/sonication technique. In contrast, the basal lamina of specimens prepared by the osmium/sonication technique has a shattered appearance that we believe is due to an increase in the fragility of the delicate fetal basal lamina.
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  • 30
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    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 18 (1991), S. 50-60 
    ISSN: 0741-0581
    Keywords: Confocal microscopy ; Light microscopy ; Scanning electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: We have adapted a tandem scanning confocal microscope for real-time, non-invasive imaging of cells under in vivo conditions. This form of in vivo confocal imaging relies on the optical sectioning abilities of the confocal microscope to obtain en face, sequential, reflected light images of cells at various depths, up to 1 mm, within opaque organs in living animals. Of major consideration in the design of an in vivo confocal microscope is maximizing the real-time detection of signals reflected from low contrast structures which can be affected by the microscope design, objective, and image detector systems. Using an in vivo confocal microscope design with a 20 × BioOptics surface contact objective we have obtained live cellular images from selected tissues including cornea, kidney, liver, adrenal, thyroid, epididymis, and muscle and connective tissue of rabbits and rats. Images were captured, digitized, and processed using a DAGE Mti low light level SIT camera coupled to a Gould IP9527 image processor. In vivo images were also compared with conventional bright field light and scanning electron microscopic images of “dead,” fixed tissues. Overall, in vivo confocal imaging can provide remarkable detail of living cells comparable to that of conventional microscopic images of “dead,” fixed, and stained tissue. A more unique feature of in vivo confocal imaging is the ability to study cellular structure and function sequentially over time in the same organ or tissue and represents a fundamentally new paradigm in microscopy. With continued refinements in the microscope, objective and detection system designs and their consequent improvements in lateral and axial resolution, in vivo confocal microscopy will enable us as observers to see what no one has been able to see before.
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  • 31
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    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 19 (1991), S. 419-428 
    ISSN: 0741-0581
    Keywords: Hand skin ; Resin cast ; Capillary loops ; Scanning electron microscopy ; Changes with age ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The microvasculature of the skin of the hand in primates, including man, was examined by means of scanning electron microscopy of corrosion casts. In this study, the microvascular patterns and structures in different areas of the hand, and the changes in vascular patterns that occur with age, have been described.The typical structure of the capillary loops in the hand can be observed in the ball of the finger of the young adult monkey. The capillary loops were formed out of not just one capillary vessel, but two or three vessels. Each capillary vessel arose and divided into several branches at the papillae, and these became descending limbs. After the loop passed a hairpin turn, the descending limbs were 1.5 times larger than the ascending limbs in the intrapapillary portion, and they became extrapapillary venules. The descending limbs connected with the postcapillary venules in the postpapillary portion and with the horizontal network. The postcapillary venules fused with each other to form the primary and secondary venous arcades. The secondary venous arcades anastomosed with each other and flowed into the subpapillary venules, which run along the dermal furrow in the fingerprint.Changes in vascular patterns with age could be observed. In the infant fingerprint, the vascular systems had not yet differentiated, especially the venous system in the dermis. In the old adult finger, the capillary loops presented complicated features deviating due to aging.
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    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 19 (1991), S. 189-202 
    ISSN: 0741-0581
    Keywords: Rat testis ; Irradiation ; Scanning electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Newly developed techniques in high-resolution scanning electron microscopy (SEM) and for tissue-processing procedures have been applied to an investigation of structures of various cells in rat testes at different stages of gonadal maturation. A series of high-resolution SEM micrographs are presented which survey the surfaces of different types of testis cells during normal development, and which also illustrate ultrastructural features of some of their intracellular organelles. In addition, a series of high-resolution SEM micrographs are presented which compare the structural features of Sertoli cells in normal testes with those in germ-cell-depleted testes obtained from rats killed at varying times after having been irradiated in utero. We describe our observations on the structural properties of surfaces and intracellular organelles in Sertoli cells, Leydig cells, peritubular myoid cells, and some classes of germinal cells. We also consider the possible role of Sertoli cell apical cytoplasmic processes in lumen formation. Similarities are pointed out between the structure of germ-cell-depleted testes, resulting from irradiation in utero, and the structure of germ-cell-depleted testes in seasonal breeders during periods of involution. Finally, we discuss advantages and disadvantages of methods employed to reveal the fine structure of intracellular organelles in cells of the testis.
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