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  • Cell & Developmental Biology  (1,675)
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  • 1
    Electronic Resource
    Electronic Resource
    Perceptions of chemistry: Why is the common perception of chemistry, the most visual of sciences, so distorted? (1996)
    Springer
    Journal of science education and technology 5 (1996), S. 193-201 
    Details
    ISSN: 1573-1839
    Keywords: Chemistry ; chemistry education ; multiple intelligences ; imagery ; visual-spatial thinking
    Source: Springer Online Journal Archives 1860-2000
    Topics: Natural Sciences in General , Technology
    Notes: Abstract Chemistry has evolved from a science dominated by mathematics into a science highly dependent on spatial-visual intelligence. Yet the chemical content of introductory courses remains taught essentially the same as 40–50 years ago. Chemistry, today, is recognized by chemists as the molecular science. Yet, school chemistry is alienated from that perception. Thanks to the computer, young people are more comfortable with visual imaging than their instructors were at the same age. Thus the time is rife to reinvigorate chemistry education by means of the visual-spatial approach, an approach wholly in conformance with the way modern chemistry is thought about and practiced.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01575303
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  • 2
    Electronic Resource
    Electronic Resource
    Three-dimensional imaging and image analysis of hippocampal neurons: Confocal and digitally enhanced wide field microscopy (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 29 (1994), S. 269-278 
    Details
    ISSN: 1059-910X
    Keywords: Three-dimensional light microscopy ; Brain slices ; Neurobiology ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The microscopy of biological specimens has traditionally been a two-dimensional imaging method for analyzing what are in reality three-dimensional (3-D) objects. This has been a major limitation of the application of one of science's most widely used tools. Nowhere has this limitation been more acute than in neurobiology, which is dominated by the necessity of understanding both large-and small-scale 3-D anatomy. Fortunately, recent advances in optical instrumentation and computational methods have provided the means for retrieving the third dimension, making full 3-D microscopic imaging possible. Optical designs have concentrated on the confocal imaging mode while computational methods have made 3-D imaging possible with wide field microscopes using deconvolution methods. This work presents a brief review of these methods, especially as applied to neurobiology, and data using both approaches. Specimens several hundred micrometers thick can be sampled allowing essentially intact neurons to be imaged. These neurons Image analysis in 3-D is as important as visualization in 3-D. Automated methods of cell counting and analysis by nuclear detection as well as tracing of individual neurons are presented. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070290403
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  • 3
    Electronic Resource
    Electronic Resource
    Confocal imaging of dendritic Ca2+ transients in hippocampal brain slices during simultaneous current- and voltage-clamp recording (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 29 (1994), S. 279-289 
    Details
    ISSN: 1059-910X
    Keywords: Fluorescence microscopy ; Ca channels ; Pyramidal neurons ; CA1 region ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Changes in the intracellular Ca2+ concentration ([Ca2+]i) within CA1 hippocampal pyramidal neurons were imaged using confocal laser scanning microscopy in conjunction with Ca2+ -sensitive fluorescent indicators. The imaging was performed in thick hippocampal brain slices while simultaneously measuring or controlling electrical activity with sharp microelectrodes or whole-cell patch-clamp electrodes. The combination of imaging and electrophysiology was essential for interpreting the changes in [Ca2+]i. We compared the increases in [Ca2+]i produced by either of two methods-direct depolarization of the cell via the somatic electrode or high-frequency stimulations of synaptic inputs. The increases in [Ca2+]i in the soma and proximal dendrites caused by both methods were of comparable magnitude and they always decayed within seconds in healthy cells. However, the spatial patterns of distal Ca2+ increases were different. Separate sets of synaptic inputs to the same cell resulted in different spatial patterns of [Ca2+]i transients. We isolated and observed what appeared to be a voltage-independent component of the synaptically mediated [Ca2+]i transients. This work demonstrates that the combination of neurophysiology and simultaneous confocal microscopy is well suited for visualizing and analyzing [Ca2+]i within neurons throughout the CNS and it raises the possibility of routinely relating subcellular [Ca2+]i changes to structural and functional modifications. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070290404
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  • 4
    Electronic Resource
    Electronic Resource
    Synaptic morphology of substance P terminals on catecholamine neurons in the commissural subnucleus of the nucleus tractus solitarii in the rat (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 29 (1994), S. 177-183 
    Details
    ISSN: 1059-910X
    Keywords: Sinus afferent pathway ; SP interneurons ; Double immunocytochemistry ; Ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The ultrastructure of substance P-containing nerve terminals synapsing on catecholamine neurons in the rat commissural subnucleus of the nucleus tractus solitarii (NTScom) was studied using a double immunocytochemical labeling technique. Although there were numerous tyrosine hydroxylase-immunoreactive (TH-I) somata present, substance P immunoreactive (SP-I) cell bodies were only occasionally found in the NTScom. At the light microscopic level, many SP-I terminals were seen closely associated with TH-I dendrites and somata. At the electron microscopic level, SP-I terminals synapsing on TH-I structures were also readily encountered. SP-I terminals contained small, clear, and predominantly spherical vesicles (32 ± 4 nm diameter), as well as large dense-cored vesicles approximately 100 nm in diameter. Postsynaptic TH-I dendritic profiles of various calibers and somata were encountered. These postsynaptic TH-I structures often showed postsynaptic densities. The morphological features of the SP-TH synapses in the present study, that is, the size of synaptic vesicles and the presence of postsynaptic densities, are quite different from those of central carotid sinus afferent synapses reported in our previous study [Chen et al. (1992), J. Neurocytol., 21:137-147]. Therefore, most of the SP terminals of the SP-TH synapses in the NTScom appear not to originate from the carotid sinus afferents. SP-I second-order neurons of the carotid sinus afferent pathway [Chen et al. (1991), J. Auton. Nerv. Syst., 33:97-98] may be one of the possible sources of such terminals. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070290216
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  • 5
    Electronic Resource
    Electronic Resource
    Localizing sites of intradendritic electrophysiological recordings by confocal light microscopy (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 29 (1994), S. 310-318 
    Details
    ISSN: 1059-910X
    Keywords: Hippocampus ; Dendrites ; 3-D imaging ; Pyramidal cell ; Neurophysiology ; Confocal microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Studies were undertaken to develop microscopic methods and imaging procedures that would permit identification of sites of intradendritic microelectrode recordings from pyramidal cells in hippocampal slice preparations. Intradendritic recording were obtained with sharp microelectrodes filled with the dye lucifer yellow. Following a recording session a neuron was iontophoretically injected with the dye and imaged by fluorescence videomicroscopy. Images were stored on videotape for later analysis. They provided a record of the location of the microelectrode recording site. After withdrawal of the microelectrode, slices were processed histologically and imaged a second time with a Bio-Rad 600 confocal attachment on an Olympus BH-2 microscope. Confocal images provided detailed anatomical information in three dimensions. In most instances, a clear identification of the recording site was achieved by comparing video images containing the recording electrode and confocal images.Neurophysiological recordings obtained from proximal and distal apical dendrites were markedly different. Proximal dendritic recordings were similar to those obtained from pyramidal cell soma. However, distal dendrites were not electroresponsive when depolarized by intracellular current injection. The techniques described here, or variations that employ patch electrodes, could provide valuable information that should further an understanding of the properties of dendrites in the central nervous system. © 1994 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070290408
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  • 6
    Electronic Resource
    Electronic Resource
    Construction and analysis of a database representing a neural map (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 29 (1994), S. 329-343 
    Details
    ISSN: 1059-910X
    Keywords: Sensory map ; Neural map ; Mechanosensory afferents ; Database ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: We describe the development and analysis of a quantitative database representing the global structural and functional organization of an entire sensory map. The database was derived from measurements of anatomical characteristics of a statistical sample of typical mechanosensory afferents in the cricket cercal sensory system. Anatomical characteristics of the neurons were measured quantitatively in three dimensions using a computer reconstruction system. The reconstructions of all neurons were aligned and scaled to a common standard set of dimensions, according to a highly reproducible set of intrinsic fiducial marks. The database therefore preserves accurate information about spatial relationships between the neurons within the ensemble.Algorithms were implemented to allow the integration of electrophysiological data about the stimulus/response characteristics of the reconstructed neurons into the database. The algorithms essentially map a physiological function onto a “field” representing the continuous distribution of synaptic terminals throughout the neural structure. Subsequent analysis allowed quantitative predictions of several important functional characteristics of the sensory map that emerge from its global organization. First, quantitative and testable predictions were made about ensemble response patterns within the map. The predicted patterns are presented as graphical images, similar to images that might be observed with activity-dependent dyes in the real neural system. Second, the synaptic innervation patterns from the sensory afferent map onto the dendrites of a postsynaptic target interneuron were predicted by calculating the overlap between the interneuron's dendrites with the afferent map. By doing so, several aspects of the stimulus/response properties of the interneuron were accurately predicted. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070290502
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  • 7
    Electronic Resource
    Electronic Resource
    Hyaluronate distribution in the regenerating retinal pigment epithelium of the rabbit: A study using confocal laser scanning microscopy (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 29 (1994), S. 344-349 
    Details
    ISSN: 1059-910X
    Keywords: Epithelium ; Eye ; Hyaluronate ; Microscopy ; Rabbit ; Regeneration ; Retina ; Sodium iodate ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The distribution of hyaluronate (HA) in regenerating retinal pigment epithelium (RPE) of the rabbit was examined using immunohistochemistry and confocal laser scanning microscopy. The goal was to determine if there is a correlation between differentiation and HA expression, like that seen in developing tissues, where HA accumulates and then disappears as the tissue matures. In normal RPE cells HA is associated mainly with the apical surface. In regenerating RPE (produced by i.v. injection of sodium iodate to damage the epithelium, regeneration arising from spared cells), HA exhibits a patchy distribution among the more immature cells and is especially prominent where they overlap or pile up on each other. Where cells are more mature and form a compact monolayer of cells, HA is expressed mainly on the apical surface, as in normal RPE. The accumulation of HA among the more immature cells in the regenerating epithelial sheet supports the hypothesis that HA influences differentiation by suppressing cell-cell associations until the proper time for their formation. © 1994 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070290503
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  • 8
    Electronic Resource
    Electronic Resource
    Color figure section (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 29 (1994), S. C1 
    Details
    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070290504
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  • 9
    Electronic Resource
    Electronic Resource
    Quantitative immunocytochemical study of secretory protein expression in parotid glands of rats chronically treated with isoproterenol (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 106-117 
    Details
    ISSN: 1059-910X
    Keywords: Acinar cells ; Duct cells ; Differentiation ; Immunogold ; Amylase ; Proline-rich proteins ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Chronic treatment of mice and rats with isoproterenol (IPR) causes marked hypertrophy and hyperplasia of the salivary glands, and alters the expression of several secretory proteins. We used quantitative postembedding immunogold labeling to study the cellular responses in the rat parotid gland during daily (up to 10 days) injections of IPR and during recovery (up to 14 days) after cessation of IPR treatment. Labeling densities of acinar cell secretory granules with antibodies to amylase and protein SMG-B1 (cross-reactive with the rat homologue of Parotid Secretory Protein, PSP) fell to 10% of control levels after 8-10 IPR injections, then increased during recovery, paralleling previous biochemical determinations of changes in protein and mRNA levels. With antibodies to proline-rich proteins (PRP), labeling densities initially fell, then subsequently showed considerable variability, but never exceeded control levels. These results contrast with biochemical determinations showing a marked induction of PRP synthesis, and may have both immunological and structural explanations.Occasional intercalated duct cells located close to the acini underwent differentiation toward an acinar-like phenotype as a result of IPR treatment. After 1-2 IPR injections, the secretory granules of these cells labeled with antibodies to amylase and PRP. Subsequently, the granules appeared electron-lucent and were increased in size and number. These observations support earlier work, suggesting that intercalated duct cells may differentiate into other gland cell types.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070310203
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  • 10
    Electronic Resource
    Electronic Resource
    Immunocytochemical investigation of the in vivo endocytosis by renal tubular epithelial cells (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 118-127 
    Details
    ISSN: 1059-910X
    Keywords: In vivo ; Tubular epithelium ; Kidney ; Endocytosis ; Cationic albumin ; Immunocytochemistry ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The internalization and degradation of glomerular filtered serum proteins by the proximal tubular epithelium has been extensively studied by microperfusion methods. By using a cationic probe that easily traverses the glomerular wall into the urinary space, we have performed a morpho-cytochemical and quantitative study of the in vivo endocytotic activity of the proximal tubular epithelial cell. Bovine serum albumin (BSA) was tagged with dinitrophenol (DNP) and cationized to pI over 8. It was introduced into the circulation of normal mice for 5, 10, and 30 minutes and the distribution of the labeling was determined by protein A-gold immunocytochemistry, using specific antiDNP antibodies on tissue sections of routinely aldehyde-fixed, osmiumpostfixed, and Epon-embedded kidneys. Cationic BSA-DNP was detected at the endothelial and epithelial sides of the glomerular basement membrane, and over capillary and tubular basement membranes. In the proximal tubular epithelial cell, labeling was present over microvilli as well as over endosomal and lysosomal compartments, with labeling intensities varying from one compartment to the other. Morphometric evaluations of the labeling demonstrated a progressive incorporation of the probe from microvilli and endocytic compartments at 5 minutes to endocytic and lysosomal compartments at 10 and then 30 minutes. When considering labeling densities, no significant differences were found on microvilli and basolateral membranes between times of circulation; however, the labeling density over endosomal and lysosomal compartments was very intense at 10 minutes compared with 5 minutes, decreasing at 30 minutes. Results from this study validate the cationic albumin tagged with DNP as a tool in the study of the quantitative aspects of protein endocytosis at the ultrastructural level, in the kidney tubular epithelium. © 1995 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/jemt.1070310204
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  • 11
    Electronic Resource
    Electronic Resource
    Immunogold localization of actin in the testis and exocrine pancreas: Spatial relationship with tight junctional strands (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 128-140 
    Details
    ISSN: 1059-910X
    Keywords: Actin ; Phospholipids ; Tight junctions ; Pancreas ; Testis ; Immunocytochemistry ; Fracture-label ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The fracture-label technique was used in conjunction with a monoclonal antibody to actin and the phospholipase A2-colloidal gold (PLA2-CG) method to examine the spatial distribution of actin filaments in relation to the three-dimensional arrangement of tight junctional strands in rat testes and exocrine pancreatic acinar cells. The intimate association of actin filaments with tight junctional strands in the pancreas and testis was also illustrated by a doublelabeling experiment in which freeze-fractured pancreas or testis was labeled with monoclonal antibody-protein A-gold (30 nm gold size) followed by incubation with a PLA2-CG complex (11 nm gold size). Freeze-fracture-exposed tight junctional strands in both testicular and exocrine pancreatic cells labeled by PLA2-CG complex indicated the presence of phospholipids in these cylindrical membranous structures. Immunolabeling of freeze-fractured testes with a monoclonal antibody to actin revealed a narrow band of gold particles juxtaposed to the cytoplasmic aspect of the protoplasmic membrane halves decorated with parallel linear arrays of cylindrical tight junctional strands. Many of the gold particles representing actin antigenic sites were in direct contact with the cross-fractured tight junctional strands. Fracture-label preparations of exocrine pancreas labeled with the monoclonal anti-actin antibody also exhibited a similar labeling pattern at the apex of acinars cells where the tight junction complex is located. Double-labeling experiments revealed the simultaneous labeling of actin and phospholipids in the same fracture-label preparations. Digestion of testicular and pancreatic tissue samples in a free PLA2 solution prior to labeling with the monoclonal antibody or PLA2-CG complex removed not only the gold labeling previously seen over the tight junctional strands but also reduced drastically the immunolabeling for actin that was previously seen associated with the tight junction complex. Taken together, results of the present study showed that actin filaments are structural components of the tight junction strands and are connected to the cytoplasmic aspect of the latter structures. The interaction between this particular cytoskeletal element and the tight junction may be through the binding of a special domain of the actin filament to the phospholipids that partially make up the tight junctional complex. © 1995 Wiley-Liss, Inc.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070310205
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  • 12
    Electronic Resource
    Electronic Resource
    Cellular functions during activation and damage by pathogens: Immunogold studies of the interaction of bacterial endotoxins with target cells (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 141-158 
    Details
    ISSN: 1059-910X
    Keywords: Immunocytochemistry ; Lipopolysaccharide ; Pneumocyte ; Macrophage ; Microtubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Bacterial endotoxins (lipopolysaccharides or LPS) are active components of Gramnegative bacteria that act on numerous cellular functions through the processes of cell activation and damage. The molecular mechanisms involved in the “endotoxic phenomenon” are not defined yet, although extensive studies have been carried out. Immunogold and electron microscopy (EM) have contributed to identify the primary target cells of endotoxins and the subcellular systems that receive the direct action of these bacterial agents. Here, we review our studies on immunogold detection of endotoxins in cellular and subcellular systems. The analysis of the interaction between endotoxins and cells was focussed on the following aspects: (1) morphological characteristics of the LPS aqueous suspensions used in experimental work; (2) binding of endotoxins to the plasma membrane of type II pneumocytes and alveolar macrophages (two of their cellular targets), and influence of the state of aggregation of the LPS; (3) movement and distribution of endotoxins inside the cell, from the plasma membrane to the nucleoplasm; and (4) interaction of LPS with microtubules and its effects on the integrity of the microtubular network. These approaches provide information at the molecular level as well as data for the establishment of physiological models of endotoxicity. © 1995 Wiley-Liss, Inc.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/jemt.1070310206
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  • 13
    Electronic Resource
    Electronic Resource
    Masthead (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995) 
    Details
    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070310301
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  • 14
    Electronic Resource
    Electronic Resource
    Immunogold labeling of oncogenic and tumor related proteins (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 159-173 
    Details
    ISSN: 1059-910X
    Keywords: Immunogold ; Electron microscopy (EM) ; Oncogene ; Mos ; Met ; Ski ; Muc1 ; Mucin ; Immunocytochemistry ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Immunogold labeling electron microscopy technique has been used to study the ultrastructural localization of oncogenic proteins: Mos, Met, Ski, and the tumor-associated protein, Muc1, as well as their relationship with other tumor-related proteins. By pre- and postembedding immunogold labeling electron microscopy techniques, we showed that the Mos protein pp39mos colocalized with microtubule bundles, suggesting that microtubulin or microtubule-associated protein(s) may be the substrate of Mos. Met protein was labeled at the microvilli of the lumen that are formed in cultured T47D cells, implying its potential involvement in lumen formation. Ski localization experiments revealed a unique globular structure “Ski body” that is present inside the nucleus of interphase chicken embryo fibroblast infected with Ski cDNA FB29 and FB2-29. Ski bodies were also found scattered in the cytoplasm of metaphase FB29 and FB2-29 Ski expressing chicken embryo fibroblasts. In T47D cells, tumor-associated protein Muc1 was associated with both the plasma membrane and the membranes of secretory vesicles in the cytoplasm. In MUC1 infected NIH3T3 cells, however, labeling showed that in addition to the plasma membrane and the membranes of secretory vesicles, some Muc1 gold spheres were seen inside the secretory vesicles, suggesting that the subcellular localization of the protein may vary in different cell types. © 1995 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/jemt.1070310207
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  • 15
    Electronic Resource
    Electronic Resource
    Introduction (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 183-183 
    Details
    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070310302
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  • 16
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    Uranium-contaminated soils: Ultramicrotomy and electron beam analysis (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 174-181 
    Details
    ISSN: 1059-910X
    Keywords: Ultramicrotomy ; Transmission electron microscopy ; Uranium in soils ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Uranium-contaminated soils from the U.S. Department of Energy (DOE) Fernald Site, Ohio, have been examined by a combination of backscattered electron imaging (BSE) and analytical electron microscopy with electron diffraction (AEM). The inhomogeneous distribution of particulate uranium phases in the soil required the development of a method for using ultramicrotomy to prepare transmission electron microscopy (TEM) thin sections from the SEM mounts. A water-miscible resin was selected that allowed comparison between SEM and TEM images, permitting representative sampling of the soil. Uranium was found in iron oxides, silicates (soddyite), phosphates (autunites), and uraninite (UO2+x). No uranium was detected in association with phyllosilicates in the soil. © 1995 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jemt.1070310208
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  • 17
    Electronic Resource
    Electronic Resource
    Morphological analysis of gastro-esophageal diseases by molecular cell techniques (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 184-192 
    Details
    ISSN: 1059-910X
    Keywords: DNA ; In situ hybridisation ; Monoclonal antibodies ; Protein ; RNA ; Western blots ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The molecular cell sciences have had a great impact in the analysis of the genetic and epigenetic events of esophageal and gastric tumorigenesis. In other regions of the alimentary tract such as the colon, the serial identification of the molecular events in the corresponding morphological lesions is perhaps most advanced. This is, in part, due to the relative ease of the histological characterisation of the premalignant lesions. In this regard the analysis of morphological and molecular adaptation in the alimentary tract is inextricable. This review aims, therefore, to judiciously assess the relative applications of contemporary techniques in investigative histopathology. © 1995 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jemt.1070310303
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  • 18
    Electronic Resource
    Electronic Resource
    Nucleic acid compartmentalization within the cell nucleus by in situ transferase-immunogold techniques (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 4-21 
    Details
    ISSN: 1059-910X
    Keywords: DNA ; RNA ; Cell nucleus ; Immunogold techniques ; Nuclear organization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: In the present review, we report on recent results obtained by in situ transferaseimmunogold techniques as to the ultrastructural distribution of DNA and RNA within the cell nucleus. Special emphasis is placed on the various nucleolar components and the various enigmatic structures of the extranucleolar region: interchromatin granules, coiled bodies, and simple nuclear bodies. These data are discussed in the light of our current understanding of the functional organization of the cell nucleus. © 1995 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jemt.1070310103
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  • 19
    Electronic Resource
    Electronic Resource
    Postembedding colloidal-gold immunocytochemistry of noncollagenous extracellular matrix proteins in mineralized tissues (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 44-62 
    Details
    ISSN: 1059-910X
    Keywords: Mineralization ; Bone ; Cartilage ; Cementum ; Dentin ; Enamel ; Osteopontin ; Osteocalcin ; Bone sialoprotein ; Amelogenin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Immunocytochemistry is a powerful tool for investigating protein secretion, extracellular matrix assembly, and cell-matrix and matrix-matrix/mineral relationships. When applied to the tissues of bones (bone and calcified cartilage) and teeth (dentin, cementum, and enamel), where calcium phosphate-containing extracellular matrices are the predominant structural component related to their weight-bearing and masticatory roles, respectively, data from immunocytochemical studies have been prominent in advancing our understanding of mineralized tissue modeling and remodeling. The present review on the application of postembedding, colloidal-gold immunocytochemistry to mineralized tissues focuses on the advantages of this approach and relates them to conceptual, theoretical, and experimental data currently available discussing matrix-mineral interactions and extracellular matrix formation and turnover in these tissues. More specifically, data are summarized regarding the distribution and role of noncollagenous proteins in different mineralized tissues, particularly in the context of how they interface with mineral, and how this relationship might be affected by the various tissue-processing steps and immunocytochemical strategies commonly implemented to examine the distribution and function of tissue proteins. Furthermore, a technical discussion is presented that outlines several different possibilities for epitope exposure in mineralized tissues during preparation of thin sections for transmission electron microscopy. Cell biological concepts of protein secretion by cells of the mineralized tissues, and subsequent extracellular matrix assembly and organization, are illustrated by examples of high-resolution, colloidal-gold immunolabeling for osteopontin, bone sialoprotein, and osteocalcin in the collagen-based mineralized tissues and for enamel protein (amelogenin) in enamel. © 1995 Wiley-Liss, Inc.
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    Immunogold studies on peroxisomes: Review of the localization of specific proteins in vertebrate peroxisomes (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 79-92 
    Details
    ISSN: 1059-910X
    Keywords: Immunogold technique ; Protein A-gold ; Peroxisome ; Subcompartment ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Peroxisomes, since their discovery as microbodies, have been studied mostly independently by electron microscopists and biochemists. The fine structure has been studied by electron microscopy, and the compositional enzymes and proteins by protein biochemistry. Electron microscopic histochemistry has been used to try to clarify the relationship between the fine structure and its constituents. The immunogold technique, a combination of electron microscopy and protein biochemistry, for the first time resolved this problem due to the high sensitivity and resolution power of the staining and the high reliability of the technique. The present paper reviews the way in which the immunogold techniques, especially the protein A-gold technique, revealed the localization of various enzymes or proteins in peroxisomes or peroxisomal subcompartments, and discusses why this technique should be employed in peroxisome research. © 1995 Wiley-Liss, Inc.
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    Immunocytochemistry of plant defense mechanisms induced upon microbial attack (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 63-78 
    Details
    ISSN: 1059-910X
    Keywords: Chitinase ; β-1,3-glucanase ; β-fructosidase ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: During the past few years, cyto- and immunocytochemical techniques have been developed and widely used for locating and identifying various molecules in plant cell compartments. The last decade has witnessed tremendous improvements in molecular cytology, thus allowing an accurate in situ detection of various components thought to play important biological functions in the plant metabolism. The use of immunocytochemistry to investigate resistance mechanisms of plants upon pathogen attack has provided key information on the defense strategy that plants elaborate during a host-pathogen interaction. Of the various proteins induced in response to infection, chitinases and β-1,3-glucanases have been the focus of particular attention due to their believed antimicrobial activity through the hydrolysis of the main fungal wall components, chitin and β-1,3-glucans. Attention has also been paid to β-fructosidase, the enzyme that hydrolyzes sucrose into glucose and fructoside. The marked accumulation of this enzyme upon pathogen infection has led to the consideration that infection may greatly infleunce the metabolic activity of colonized tissues by creating alterations of source-sink relationships. Another facet of the plant's defense strategy that has been the focus of considerable interest is related to the accumulation of structural compounds, such as hydroxyproline-rich glycoproteins and callose, to reinforce the wall architecture, thus decreasing vulnerability to microbial enzymes. A number of alternatives designed to improve plant protection towards pathogen invasion have been suggested. Among these, the production of transgenic plants expressing constitutively a foreign resistance gene and the pretreatment of plants with elicitors of defense reactions have been the subject of intensive studies at the molecular, biochemical, and cytological levels. Results of such studies clearly demonstrate the important contribution that cyto- and immunocytochemical approaches can make to our knowledge of how plants defend themselves and how plant disease resistance can be directly enhanced. These approaches will undoubtedly be active areas for future research in the development of biological control alternatives in which the mode of action of the product used is of key importance. © 1995 Wiley-Liss, Inc.
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    Masthead (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995) 
    Details
    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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    URL: http://dx.doi.org/10.1002/jemt.1070310401
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    Transmission EELS of oxide superconductors with a cold field emission TEM (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 30 (1995), S. 208-217 
    Details
    ISSN: 1059-910X
    Keywords: Superconductors ; Electron energy loss spectrometry ; Transmission electron microscope ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Electron energy loss spectrometry (EELS) with a cold field emission gun (cFEG) transmission electron microscope (TEM) is implemented to analyze the evolution of the electronic structure and dielectric function of oxide superconductors. The O-K core loss spectra of p-type doped oxide superconductors are analyzed in terms of holes formation on oxygen sites, while low loss spectra are analyzed for free carrier plasmas, other spectral excitations, and their crystallographic confinement.It is illustrated that the transmission EELS with a cFEG TEM very much complement soft X-ray absorption spectroscopy and optical spectroscopy, with the added advantages of high spatial resolution (∼1-100 nm), and is compatible with other analytical, diffraction, and imaging techniques, which are readily available in a cFEG TEM. © 1995 Wiley-Liss, Inc.
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    Freeze-fracture study of Bodo sp. (Kinetoplastida: Bodonidae) (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 30 (1995), S. 246-251 
    Details
    ISSN: 1059-910X
    Keywords: Bodonidae ; Cell surface ; Chemical fixation ; Cryofixation ; Quick freeze ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Freeze-fracture technique was used to analyse the structure of conventionally fixed and quickly frozen Bodo sp., a free-living kinetoplastid. In the former method, chemically fixed and cryopreserved cells presented a corrugated membrane pattern in the flagella and cell body surfaces. In the latter, however, replicas from quickly frozen unfixed flagellates showed membranes with a smoother aspect, allowing the observation of intramembranous particles (IMPs) on the fracture faces, hardly detectable in previously fixed samples. The IMPs were randomly distributed throughout the cell surface, except in the sparsely seen short IMP rows. © 1995 Wiley-Liss, Inc.
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    Interaction of colloidal gold-labelled glucosylated albumin with endothelial cell monolayers: Comparison between cryofixation and glutaraldehyde fixation (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 30 (1995), S. 252-257 
    Details
    ISSN: 1059-910X
    Keywords: Permeability tracer ; Endocytosis ; Transcytosis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Bovine aortic endothelial cells (BAEC) were exposed to glucosylated albumin-gold complexes (GgA), and the distribution of the tracers was compared after cryofixation and after glutaraldehyde fixation. Morphometric analysis revealed differences in the GgA distribution depending upon the method of fixation used. In BAEC monolayers cryofixed after 3 min of incubation with GgA, tracer was observed in predominately apically located vesicular elements. After 16 min of incubation, all vesicular elements were labelled, and multivesicular bodies were the prominent labelled structure. In contrast, chemically fixed monolayers exhibited a heterogeneous distribution of GgA within vesicular profiles after 3 min and 16 min of GgA incubation. The differences in tracer distribution depending upon the fixation method must be resolved before the mechanism of vesiclemediated endothelial cell transport function is defined and universally accepted. © 1995 Wiley-Liss, Inc.
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    A method for preparation of immobilized cells and tissues for light and electron microscopy studies (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 30 (1995), S. 265-267 
    Details
    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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    URL: http://dx.doi.org/10.1002/jemt.1070300308
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    Microstructures in high-Tc Bi(Pb)-family 2212 superconductors as revealed by scanning and transmission electron microscopy (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 30 (1995), S. 258-264 
    Details
    ISSN: 1059-910X
    Keywords: Microstructure ; High-Tc Bi(Pb)-2212 superconductor ; Sol-gel method ; SEM ; TEM ; Powder XRD ; EPMA ; Magnetization ; Crack ; Amorphous substance ; Modulated structure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Microstructures of Bi(Pb)-family 2212 superconductors, which were prepared by a sol-gel method with three different compositions, were examined mainly by scanning and transmission electron microscopy. The magnetization of the specimens strongly depends on the ratio between Bi and Pb content, while Tc is almost constant. In specimen 1, prepared with the nominal composition of Bi/Pb = 9/1, small grains of 2212 phase are formed with a minor fraction of some impurity phases. In specimen 2, with Bi/Pb = 17/3, which is optimum from the viewpoint of magnetization, large grains of the 2212 phase are formed during heating at 800°C, also with the impurity phases. In specimen 3, with Bi/Pb = 8/2, the 2212 grains are divided by layers of (Bi0.86, Pb0.14) (Ca0.7, Sr0.3)Ox. Moreover, plate-like 2212 crystals are severely bent so that small cracks appear often with an inclusion of amorphous substance being rich in Ca and Pb. These layers and cracks must degrade the magnetization. A modulated structure of Bi-type is formed in the 2212 grains of specimens 1 and 2, while not only Bi-type but also Pb-type are formed in specimen 3. The wavelength of Bi-type is different for each specimen. © 1995 Wiley-Liss, Inc.
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    Masthead (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 30 (1995) 
    Details
    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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    URL: http://dx.doi.org/10.1002/jemt.1070300401
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    Introduction (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 30 (1995), S. 269-270 
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    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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    URL: http://dx.doi.org/10.1002/jemt.1070300402
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    Crystal structure, chemical composition, and extended defects of the high-Tc (Bi,Pb)2Sr2Can-1CunO4+2n+δ compounds (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 30 (1995), S. 218-245 
    Details
    ISSN: 1059-910X
    Keywords: (Bi,Pb)2Sr2Can-1CunO4+2n+δ ; HR-TEM ; Crystal structure ; Microstructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: This paper summarizes results obtained by high-resolution transmission electron microscopy on the crystal structure and microstructure of the (Bi,Pb)2Sr2Can-1CunO4+2n+δ high-Tc superconducting oxides. The experimental basis for the work presented here are high-resolution structure images obtained at ultra-thin (3 nm) areas of carefully prepared transmission electron microscope (TEM) samples. The analysis was carried out on a 400 kV TEM equipped with a pole piece yielding 0.17 nm point-to-point resolution. From the images obtained the projected crystal potential of the cations can be extracted directly, as confirmed by detailed image simulation. Structural analysis of the oxygen sublattice remains an unsolved problem by high-resolution TEM (HRTEM), mainly because of the small scattering factors, and thus the contribution of the oxygen sublattice to the image contrast is small. The (Bi,Pb)2Sr2Can-1CunO4+2n+δ phases are modulated structures that can be understood as an average structure plus a superimposed displacement field. The crystal structure consists of BiO double layers and perovskite-type cuboids (containing Sr, Ca, Cu, and O), which are sandwiched between the BiO double layers. The displacement field can be directly analyzed by HRTEM, and the largest displacement amplitudes of 70 pm were determined for the Bi atoms in the n = 1 compound. The chemical composition of the n = 2 and n = 3 compounds was determined by EDX in the TEM for the cation sublattice. A significant (Ca + Sr) deficiency (approximately 10%) with respect to Cu was found. The (Sr + Ca)/Cu mole fraction ratio was 1.31 for the Bi-2212 phase and 1.14 for the Bi(Pb)-2223 phase. The oxygen content cannot be determined by EDX in the TEM with the accuracy necessary for a correlation with electrical and superconducting properties. The defect structure present in these materials, that is, intergrown lamellae with different crystal structures and equal or different chemical compositions, stacking faults, and grain boundaries, is summarized. The importance of grain boundaries for understanding and improving superconducting properties is emphasized. © 1995 Wiley-Liss, Inc.
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    Gap junctions in the vertebrate retina (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 408-419 
    Details
    ISSN: 1059-910X
    Keywords: Neuronal mosaic ; Coupling ; Network ; Dopamine ; Nitric oxide ; Connexin ; Development ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The vertebrate retina is a highly laminated assemblage of specialized neuronal types, many of which are coupled by gap junctions. With one interesting exception, gap junctions are not directly responsible for the ‘vertical’ transmission of visual information from photoreceptors through bipolar and ganglion cells to the brain. Instead, they mediate ‘lateral’ connections, coupling neurons of a single type or subtype into an extended, regular array or mosaic in the plane of the retina. Such mosaics have been studied by several microscopic techniques, but new evidence for their coupled nature has recently been obtained by intracellular injection of biotinylated tracers, which can pass through gap junctional assemblies that do not pass Lucifer Yellow. This evidence adds momentum to an existing paradigm shift towards a population-based view of the retina, which can now be envisaged both as an array of semi-autonomous vertical processing modules, each extending right through the retina, and as a multi-layered stack of interacting planar mosaics, bearing some resemblance to a set of interleaved neural networks. Junctional conductance across mosaics of horizontal cells is known to be controlled dynamically with a circadian rhythm, and other dynamically-regulated conductance changes are also likely to make important contributions to signal processing. The retina is an excellent system in which to study such changes because many aspects of its structure and function are already well understood. In this review, we summarize the microscopic appearance, coupling properties and functions of gap junctions for each cell type of the neural retina, the regulatory properties that could be provided by selective expression of different connexin proteins, and the evidence for gap junctional coupling in retinal development. © 1995 Wiley-Liss, Inc.
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    Differential connexin distribution accommodates cardiac function in different species (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 420-436 
    Details
    ISSN: 1059-910X
    Keywords: Gap junctions ; Connexin40 ; Connexin43 ; Conduction system ; Mammals ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Using immunohistochemical staining, the distribution of connexin40 (Cx40) and connexin43 (Cx43) was studied in rat, guinea pig, porcine, bovine and human hearts. These species display differences in the degree of morphological differentiation of the conduction system. This study was performed in the anticipation that comparison of the distributions of Cx40 and Cx43 in young and adult specimens may provide clues as to the physiological role of connexins in the heart. To a large extent, the distribution patterns of Cx40 and Cx43 are comparable between species. In neonates and adults, Cx43 was immunolocalized throughout the working myocardium, but in the conduction system Cx43 was detected only after birth. Cx40 was found to appear slightly earlier in development than Cx43 and to disappear when levels of Cx43 became more abundant. This time course was seen in working myocardium and in the ventricular conduction system. Together these data suggest that expression of Cx40 induces or facilitates expression of Cx43, while abundant expression of Cx43 in turn leads to suppression of Cx40 expression. The exceptions to this may represent blocks in this potential regulatory sequence. A second conclusion is that Cx40 and Cx43 containing gap junctions appear in the ventricular conduction system from distal to proximal and only after birth. This indicates that terminal differentiation of the conduction system occurs unexpectedly late in development. © 1995 Wiley-Liss, Inc.
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    Freeze-Fracture, Deep-Etch, and Freeze-Substitution Studies of Olfactory Epithelia, With Special Emphasis on Immunocytochemical Variables (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 32 (1995), S. 337-356 
    Details
    ISSN: 1059-910X
    Keywords: Olfactory signal transduction ; G proteins ; Adenylyl cyclase ; Rapid freezing ; Lowicryl ; Cilia ; Microvilli ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Freeze-fracturing and deep-etching are a well-suited set of methods to study membrane and cytoplasmic features. Various approaches are available. Possible variables include tissue preparation, fracturing only or fracturing followed by etching, modes and materials of replication, and various ways of combining freeze-fracturing and/or deep-etching with (immuno)cytochemistry. Freeze-substitution, in particular combined with embedding in methacrylate resins such as the Lowicryls, is becoming rather widely accepted for purposes of ultrastructural (immuno)cytochemistry. Most investigators active in this field agree that this combination yields superior results compared to (immuno)cytochemistry combined with more conventional means of thin section transmission electron microscopy. Yet relatively little information is available on the variations that can occur with different approaches of freeze-substitution immunocytochemistry. This review deals with some of the variations in freeze-fracturing, freeze-etching, and freeze-substitution as applied to olfactory epithelial structures and with the effectiveness of observations obtained by application of the above sets of methods in relating the special morphology of olfactory epithelial cellular structures with those obtained by other approaches. Indeed, the data obtained continue to provide an integral image in which that morphology can be related to the special biochemistry, cell and molecular biology, and electrophysiology of olfactory epithelial structures. © 1995 Wiley-Liss, Inc.
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    Instructive induction of prostate growth and differentiation by a defined urogenital sinus mesenchyme (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 30 (1995), S. 319-332 
    Details
    ISSN: 1059-910X
    Keywords: Rat ; Prostate ; Epithelium ; Stroma ; Cytodifferentiation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Instructive influences of fetal mesenchyme were examined in heterotypic tissue recombinants consisting of urogenital sinus mesenchyme (UGM) from male and female rats and distal ductal tips from adult rat prostate. Tissues were grown under the renal capsule of male hosts for periods up to 28 days. Resultant growths exhibited typical prostate histology. Expression of lobe-specific proteins for the ventral (prostatic steroid binding protein [PSBP]) lateral (seminal vesicle secretion II [SVS II]), and dorsal prostate (secretory transglutaminase [TGase]) were examined by immunocytochemistry. Male or female UGM combined with terminal segments of the ventral or dorsal prostate and immunolabeled with antibodies to lobe-specific proteins demonstrated expression of all three secretory products. The pattern of staining was consistent with a compound inductive response from the UGM. Unique to this study was our ability to use a defined mesenchymal tissue (female ventral mesenchymal pad [VMP]). This tissue is specifically associated with ductal branching morphogenesis and cytodifferentiation of the ventral prostate. Distal ductal tips from the dorsal lobe of the adult male prostate when recombined with female VMP and grown in vivo exhibited transformation of secretory phenotype, and the epithelium expressed mRNAs for PSBP. Immunocytochemistry of serial sections did not demonstrate labeling for TGase in the new epithelial growth. Ultrastructural analysis of the heterotypic recombinants indicated that the epithelium had similar characteristics to those of normal ventral prostate. Early stages of the mesenchymal-epithelial interactions resulted in dedifferentiation of the adult epithelium to solid cords of stratified cells. These findings illustrate the potent instructive capacity of a defined fetal UGM to influence development and cytodifferentiation of adult prostate epithelium. © 1995 Wiley-Liss, Inc.
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    Analysis of cell death and cell proliferation in embryonic stages, normal adult, and aging prostates in human and animals (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 30 (1995), S. 342-350 
    Details
    ISSN: 1059-910X
    Keywords: Apoptosis ; BPH ; Growth regulatory factors ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Homeostasis in the prostate is recognized to be maintained by a complex interplay between the opposing actions of cell proliferation and Cell death. Growth regulatory factors that promote or inhibit cell proliferation and promote cellular death have been identified in the prostate. The integration of these forces involves cellular cooperation between the prostatic stroma and epithelium. Hormone-regulated production of growth regulatory factors by one cell type may determine growth stimulation, inhibition, or cell death in a reciprocal cell partner. Imbalance between net cell proliferation and net cell death rates may result in abnormal growth leading to BPH. Additional study of the growth regulatory factors associated with distal vs. proximal epithelial cells and stroma and comparison of growth factor expression by the neonatal, postnatal growing, adult quiescent, and aging prostates will likely provide further insight into the regulation of prostate cell division and death. © 1995 Wiley-Liss, Inc.
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    A utilization of the phase spectrum for the correction of image drift in high resolution transmission electron microscopy (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 30 (1995), S. 351-352 
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    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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    URL: http://dx.doi.org/10.1002/jemt.1070300410
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    Morphological study of changes in the baboon oviductal epithelium during the menstrual cycle (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 32 (1995), S. 13-28 
    Details
    ISSN: 1059-910X
    Keywords: Ciliated and secretory cells as related to menstrual cycle ; LM ; SEM ; TEM ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Oviductal epithelium of the baboon, Papio cynocephalus, was studied utilizing light, scanning, and transmission electron microscopy. Results of counts made of nonciliated, ciliated, and ciliogenic cells were analyzed statistically. The percentages of nonciliated cells of the fimbria and ampulla during the early proliferative and late secretory stages of the menstrual cycle were significantly greater than those during the mid-proliferative and late proliferative-early secretory stages, due to deciliation. This paper emphasizes previously unreported apical surface morphology as viewed by scanning and transmission electron microscopy. The microvillar pattern of the fimbrial secretory cells differs from that of the ampullar and isthmic cells in that the microvilli originate from thick apical protrusions and vary greatly in length and number as related to the cycle. A ridge demarcating the apical intercellular junction is composed of rows of microvilli during the early proliferative and late secretory stages. During the early proliferative and late secretory stages an increased degree of invagination of the basal and lateral plasma membranes occurs as the height and width of the cells decreases. The general numbers and distribution of the organelles of the various types of oviductal cells agree with that described for the ampulla and isthmus by Verhage et al. [(1990) Am. J. Anat., 187:81-90]; however, fimbrial epithelium was not included in that study. Other cyclic ultrastructural changes not examined previously include variation in the number of lipid droplets and their location, and in the number and relationships of glycogen particles to other structures. © 1995 Wiley-Liss, Inc.
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    Microwave oven heating enhances the ultrastructural detection of antigens in bioacryl-embedded tissue sections (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 32 (1995), S. 75-76 
    Details
    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/jemt.1070320108
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    Introduction (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 32 (1995), S. 77-78 
    Details
    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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    URL: http://dx.doi.org/10.1002/jemt.1070320202
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    Morphology and physiological significance of parathyroid glands in reptiliaDedicated to Prof. C. J. Dominic (Department of Zoology, Banaras Hindu University, Varanasi, U.P.) and Prof. Samir Bhattacharya (Department of Zoology, Visva-Bharti, Santiniketan, West Bengal). (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 32 (1995), S. 91-103 
    Details
    ISSN: 1059-910X
    Keywords: Chelonia, Crocodilia ; Rhynchocephalia ; Squamata ; Parathyroid hormone ; Development ; Seasonal variation ; Parathyroidectomy ; Topography ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Adult reptiles possess one or two pairs of parathyroid glands that have been shown in many species to derive from the third and fourth pharyngeal pouches, respectively. Up to five pairs may develop during early embryonic life. Excess glands may involute during late embryogenesis. The location of the parathyroid glands differs in the various species. As a general rule, they lie just anterior to the heart, the anterior pair (parathyroid III) being associated with the carotid artery, the posterior pair (parathyroid IV) with the aortic arch. In snakes, however, the anterior pair (parathyroid III) is associated with the carotid artery near the angle of the jaw. As shown by light microscopy and, to a lesser extent, by electron microscopy, the parathyroid parenchyma comprises secretory cells which may form dark and light variants, occasional oxyphil cells, and stellate cells. They are arrangend in cords separated by connective tissue containing a capillary network. Parathyroid secretory cells often form follicles which might be the result of degeneration. Degeneration may occur as a form of involution during winter in species undergoing seasonal changes. The product of parathyroid cells, the parathyroid hormone, is responsible for the maintenance of blood calcium concentration. The sites of action - bones, kidneys, intestine, endolymphatics, and dermal skeleton - are not well understood or not investigated. In some turtles, parathyroid hormone is not the (main) factor for the regulation of calcium homeostasis. © 1995 Wiley-Liss, Inc.
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    Expression of myosin heavy chain isoforms and myogenesis of intrafusal fibres in rat muscle spindles (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 30 (1995), S. 390-407 
    Details
    ISSN: 1059-910X
    Keywords: Development ; Deefferentation ; Muscle cell lineages ; Spindle origin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: This review concerns the pattern of expression and regulation of myosin heavy chain (MHC) isoforms in intrafusal fibres of rat muscle spindles detected by immunocytochemistry. The three types of intrafusal fibres - nuclear bag1, nuclear bag2, and nuclear chain fibres - are unique in co-expressing several MHCs including special isoforms such as slow tonic and α cardiac-like MHC and isoforms typical of muscle development, such as embryonic and neonatal MHC. The distinct intrafusal fibre types appear sequentially during rat hind limb development, the nuclear bag2 precursors being first identifiable at 17-18 days in utero as the only primary myotubes expressing slow tonic MHC. Sensory innervation is required for the expression of “spindle-specific” MHC isoforms. Motor innervation contributes to the diversity in distribution of the different MHCs along the length of the nuclear bag fibres. It is suggested that unique populations of myoblasts are destined to become intrafusal fibres during development in the rat hind limb muscles and that the regional heterogeneity in MHC expression is related both to sensory and motor innervation and to the properties of the myoblast lineages. These distinct features make intrafusal fibres an attractive in situ model for investigating myogenesis, myofibrillogenesis, and the mechanisms regulating MHC expression. © 1995 Wiley-Liss, Inc.
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    Development and postnatal regulation of adult myoblasts (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 30 (1995), S. 366-380 
    Details
    ISSN: 1059-910X
    Keywords: Myogenesis ; Myosin ; MyoD ; Myogenin ; PDGF ; FGF ; Transferrin ; Chicken ; Rat ; C2 cells ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The myogenic precursor cells of postnatal and adult skeletal muscle are situated underneath the basement membrane of the myofibers. It is because of their unique positions that these precursor cells are often referred to as satellite cells. Such defined satellite cells can first be detected following the formation of a distinct basement membrane around the fiber, which takes place in late stages of embryogenesis. Like myoblasts found during development, satellite cells can proliferate, differentiate, and fuse into myofibers. However, in the normal, uninjured adult muscle, satellite cells are mitotically quiescent. In recent years several important questions concerning the biology of satellite cells have been asked. One aspect has been the relationship between satellite cells and myoblasts found in the developing muscle: are these myogenic populations identiacal or different? Another aspect has been the physiological cues that control the quiescent, proliferative, and differentiative states of these myogenic precursors: what are the growth regulators and how do they function? These issues are discussed, referring to previous work by others and further emphasizing our own studies on avian and rodent satellite cells. Collectively, the studies presented indicate that satellite cells represent a distinct myogenic population that becomes dominant in late stages of embryogenesis. Moreover, although satellite cells are already destined to be myogenic precursors, they do not express any of the four known myogenic regulatory genes unless their activation is induced in the animal or in culture. Furthermore, multiple growth factors are important regulators of satellite cell proliferation and differentiation. Our work on the role of one of these growth factors [platelet-derived growth factor (PDGF)] during proliferation of adult myoblasts is further discussed with greater detail and the possibility that PDGF is involved in the transition from fetal to adult myoblasts in late embryogenesis is brought forward. © 1995 Wiley-Liss, Inc.
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    Computer graphics of SEM images facilitate recognition of chromosome position in isolated human metaphase plates (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 30 (1995), S. 408-418 
    Details
    ISSN: 1059-910X
    Keywords: Mitosis ; Chromosomes ; Lung cells ; HeLa S3 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: There is general agreement that at the time of mitosis chromosomes occupy precise positions and that these positions likely affect subsequent nuclear function in interphase. However, before such ideas can be investigated in human cells, it is necessary to determine first the precise position of each chromosome with regard to its neighbors. It has occurred to us that stereo images, produced by scanning electron microscopy, of isolated metaphase plates could form the basis whereby these positions could be ascertained. In this paper we describe a computer graphic technique that permits us to keep track of individual chromosomes in a metaphase plate and to compare chromosome positions in different metaphas plates. Moreover, the computer graphics provide permanent, easily manipulated, rapid recall of stored chromosome profiles. These advantages are demonstrated by a comparison of the relative position of group A - specific and groups D - and G - specific chromosomes to the full complement of chromosomes in metaphase plates isolated from a nearly triploid human-derived cell (HeLa S3) to a hypo-diploid human fetal lung cell. © 1995 Wiley-Liss, Inc.
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    Masthead (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 30 (1995) 
    Details
    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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    URL: http://dx.doi.org/10.1002/jemt.1070300601
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    Comparison of SEM processing methods for cultured human lens epithelial cells grown on flat and microcarrier bead substrates (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 30 (1995), S. 419-426 
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    ISSN: 1059-910X
    Keywords: Sublimation drying ; Peldri II ; Tert-butyl alcohol ; Cell morphology ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The increasing importance of in vitro models has presented new challenges in SEM processing techniques. The present study has evaluated the quality of preservation of cultured human lens epithelial cells processed by critical point, Peldri II, and tert-butyl alcohol drying. Specimens processed by critical point drying produced specimens with severe cracking of cell processes and microcracks across cell membrane surfaces. Peldri II and tert-butyl alcohol drying eliminated breakage of the filopodia and lamellipodia as well as eliminating the microcracks across the apical membrane surface. The morphology of lens epithelial cells grown on Cytodex 3 beads appeared rounded with convoluted membrane surfaces. These morphological features were present for cells processed by all three methods. Cytodex 3 beads were subsequently shown to shrink 52% in diameter during dehydration, which results in an 89% reduction in volume for the bead. Cells grown on Biosilon beads, which do not shrink, had a morphology similar to the cells grown on a flat substrate. These results indicate that Peldri II and tert-butyl alcohol drying offer an attractive alternative to critical point drying when preparing cultured cells for SEM. Interpretation of cultured cell morphology must consider shrinkage of the substrate material as a possible contributor to artifact. © 1995 Wiley-Liss, Inc.
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    Improved antigenic preservation of plant tissue by low temperature processing in LR white resin (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 531-532 
    Details
    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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    URL: http://dx.doi.org/10.1002/jemt.1070310609
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    Functions of proteins secreted by oviduct epithelial cells (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 32 (1995), S. 1-12 
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    ISSN: 1059-910X
    Keywords: Spermatozoon ; Fertilization ; Embryo ; Growth factors ; Insulin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Studies on embryonic development in vitro as well as observations in vivo, suggested that two aspects of oviduct physiology are important for early development. On one side has to be considered the oviduct “environment”: temperature, pH, osmotic pressure, nutrients, oxygen tension, free radical scavengers, etc. On the other, the oviduct “active components”: stimulatory and/or regulatory molecules, supposed to finely regulate the fertilisation process and the first differentiative steps.While the physical environment of the oviduct has been under investigation for some decades, studies on oviduct-specific molecules and their functions have only been developed much more recently. The amount of information on this topic, however, has rapidly reached the size that demands a summary.In this review the descriptive literature on oviduct specific proteins will be examined as a basis for illustrating the possible functions of these molecules. In particular their role in fertilisation and early embryonic cleavages will be analysed in some details. Finally a section is devoted to the presence and physiological significance of growth factors in oviduct fluid. © 1995 Wiley-Liss, Inc.
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    Ultrastructure and histochemistry of acid mucus glycoproteins in the estrous mammal oviduct (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 32 (1995), S. 29-49 
    Details
    ISSN: 1059-910X
    Keywords: Mucus ; Mucous surfaces ; Glycocalyx ; Glycoproteins ; Estradiol ; Fallopian tube ; Oviduct ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The mucous surfaces of the oviducts of mammals, especially humans, are dependant on estradiol. The mucus glycoproteins and glycocalyceal glycoproteins have, however, barely been studied. Biochemical analyses have focussed on the relatively low molecular weight glycoproteins likely to be found in more serous-type granules of the ampulla and not on the very high MW glycoproteins typical of mucus and represented in the isthmus by morphological evidence of mucus secretion. Quantitatively, secretion from the ampulla is likely to predominate, because of its huge surface area compared with the isthmus. But functional closure of the isthmus under the influence of estradiol in the absence of progesterone means that it is the isthmus where luminal secretions accumulate - and where mucus glycoproteins will exert their most important effects on spermatozoa ascending the reproductive tract, and then on fertilized ova en route to the uterus. Further study of the extracellular, intraluminal, carbohydrate-rich environment of the oviductal isthmus, especially in humans, is likely to prove rewarding. Sampling of these secretions is now feasible using transvaginal, transuterine fallopian tube catheters that are in clinical use. © 1995 Wiley-Liss, Inc.
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    A human oviduct-specific glycoprotein: Synthesis, secretion, and localization during the menstrual cycle (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 32 (1995), S. 57-69 
    Details
    ISSN: 1059-910X
    Keywords: Oviduct ; Glycoprotein ; Antibody ; cDNA ; Human ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The major objective of this study was to examine the hormonal regulation of a human oviduct-specific glycoprotein (huOGP) throughout the menstrual cycle and in all regions of the human oviduct. Regulation of synthesis and secretion was examined at both the protein (Western immunoblots and immunocytochemistry) and mRNA (Northern and slot blots) levels and correlated with changes in the morphological features of the oviductal epithelial cells throughout the cycle. Immunoblot analysis of oviductal fluid and explant culture media from all regions of the oviduct demonstrated that huOGP is primarily found during the follicular stage of the cycle and is not present in serum, follicular fluid, or uterine endometrium. Moreover, two-dimensional (2-D) immunoblots showed that all major isoelectric variants of huOGP observed on 2-D fluorographs are immunologically related. Light microscopic immunocytochemistry localized huOGP to oviductal secretory cells in both ampulla and isthmic regions, with the most intense immunoperoxidase staining seen in midcycle samples. Using an indirect immunogold technique at the electron microscopic level, huOGP was specifically localized to secretory granules of the ampullary and isthmic nonciliated epithelial cells. The ultrastructural characteristics of these secretory cells during the mid to late follicular phase of the cycle suggested elevated protein synthetic activity. In addition, mRNA expression for huOGP was elevated in all regions of the oviduct in midcycle specimens. Collectively, these data indicate that huOGP is a major tissue-specific, stage-specific secretory product of the human oviduct during the periovulatory stage of the cycle and support the hypothesis that huOGP synthesis and secretion may be regulated by fluctuations in the levels of estrogen and progesterone. © 1995 Wiley-Liss, Inc.
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    Mammalian parathyroids: Morphological and functional implicationsDedicated to Robert Wyler, Zürich, on the occasion of his seventieth birthday. (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 32 (1995), S. 120-128 
    Details
    ISSN: 1059-910X
    Keywords: Parathyroid cell variants ; Fixation ; Membrane disintegration ; Secretory activity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Fixation with aldehydes is achieved either by immersion or perfusion. The parenchyma of parathyroid glands fixed by immersion consists of dark cells containing a lot of membranes of those organelles which are concerned with hormone secretion, light cells which are poor in these organelles, intermediate forms between the two, and multinuclear syncytial cells. They have been attributed to represent different functional stages of secretory activity, the dark cell being in an active form, the light cell in a resting form. Studies of the parathyroids of mice, rats, rabbits, cats, dogs, pigs, cattle, sheep, goats, and horses employing various fixation protocols clearly demonstrate that light cell variants and multinuclear syncytial cells are formed during improper immersion fixation as a result of membrane disintegration. Parathyroids fixed by perfusion or by immersion in an appropriate fixation medium comprise only one cell type which correspond to the dark chief cell. Parathyroid cells are polar cells bearing some of the rough endoplasmic reticulum in the basal pole, the rest of it, the Golgi complex, and secretory granules in the apical pole. The secretory product is released by exocytosis at the apicolateral domain of the plasma membrane into the intercellular space. Secretory activity can be altered experimentally, leading to drastic changes in the amount of cell membrane related to hormone synthesis, intracellular transport, exocytic release, and secretion coupled membrane retrieval. The sensitive reaction of parathyroid cells to both the mode of fixation and to fixation media demands careful evaluation of the fixation protocol. This and the polarity of parathyroid ceils have to be borne in mind for estimating secretory activity on the basis of morphological criteria. © 1995 Wiley-Liss, Inc.
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    Quantification of particle sizes with metal replication under standard freeze-etching conditions: A gold ball standard for calibrating shadow widths was used to measure freeze-etched globular proteins (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 32 (1995), S. 312-329 
    Details
    ISSN: 1059-910X
    Keywords: Lactose repressor ; Mitochondrial ATPase ; F1 ; Freeze-etching method ; 45° unidirectional Pt-C replication of globular proteins ; 45° and vertical replication of gold ball standards on indirect carbon films ; Transmission electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The real size of platinum-carbon (Pt-C) replicated particles is not directly equivalent to either its metal-coated diameter or its shadow width. This paper describes two indirect methods, shadow widths and coated particle diameters, for determining a particle's actual size beneath a Pt-C replication film. Both produce equivalent measurements using the same standardized conditions: 2.3 nm Pt-C films deposited at a 45° angle on an ≈ -100°C surface in a 10 -6 torr vacuum. For the first method, gold balls nucleated in a partial pressure of helium and deposited on flat indirect carbon films (root mean square roughness of 0.8 nm) on 400 mesh grids were used as test particles for calibrating shadow widths as a function of particle size. The gold ball test specimens were replicated, and a distribution of Pt-C shadow widths orthogonal to the Pt-C deposition direction was measured and averaged for gold balls 1.5 ± 0.25 nm, 2.0 ± 0.25 nm, etc. The diameter of each gold ball was measured within the Pt-C film along with its shadow width because the Pt-C did not obscure or adhere well to the gold. The shadow width distributions for each gold size do not differ significantly from log normal. Two proteins, the lactose repressor and the mitochondrial ATPase, F1, were also used as replication test objects. Negative staining of both proteins was conducted to measure their average diameters. In the second method, a distribution of Pt-C-coated lac repressor diameters perpendicular to the shadow direction was measured. The Pt-C film thickness measured on the quartz crystal monitor was subtracted from the average metal-coated protein diameter to obtain the lac repressor's diameter. The Pt-C-coated particle diameter distributions also did not differ significantly from log normal. While doing this work it was discovered that outgassing the Pt-C electron gun greatly affected Pt-C film granularity: 19 sec produced a high contrast, granular Pt-C film, whereas 120 sec yielded a low contrast, less granular Pt-C film. Both gold balls and protein particles were subjected in separate experiments to either 19 or 120 sec of outgassing of the Pt-C gun prior to Pt-C replication. Outgassing had a profound effect on the average size of the Pt-C shadow widths on both gold and protein particles. The Pt-C gun outgassing procedure also determined the smallest replicated particle that could be resolved. The frequency of some smaller gold ball sizes detected after replication was reduced disproportionately with 19 sec vs. 120 sec outgassing. However, Pt-C gun outgassing did not affect the average measured diameter of the Pt-C-coated protein particles. The “geometric assumption” that each metal-coated particle creates a shadow width the same size as the metal-coated particle diameter was tested using a globular protein. Pt-C replication of protein particles at a 45° and 20° angle could not confirm the geometric assumption because an average shadow width was always significantly larger than its average Pt-C-coated particle diameter. A model for how the large shadow widths are formed is presented. Gold balls were also replicated at a 45° angle with current high resolution conditions at a substrate temperature of -185°C, and the results of these replicas were compared to the results reported here at ˜-100°C. © 1995 Wiley-Liss, Inc.
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    Effects of extracellular matrix on differentiation of mouse fetal gonads in the absence of mesonephros in vitro (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 32 (1995), S. 437-448 
    Details
    ISSN: 1059-910X
    Keywords: Sexual differentiation ; Organ culture ; Sertoli cell ; Leydig cell ; Mesonephros ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The influence of mesonephric tissues and the extracellular matrix on mouse gonadal differentiation was examined in vitro. Gonadal ridges, with or without the adjacent mesonephric region, were removed from mouse embryos on day 12 post coitum (p.c.), and cultured in the presence or absence of reconstituted basement membrane (matrigel) for 5 days. Culturing control undifferentiated testes with mesonephric tissues induced normal testicular differentiation. When testes without mesonephric tissues were cultured in the absence of matrigel, testicular cord formation was not observed in the explants. Sertoli cells were irregularly arranged in the testicular parenchyma, and no continuous basal lamina was formed around the Sertoli cells. However, when testes without mesonephric tissues were embedded in matrigel and cultured for 5 days, the Sertoli cells were organized into testicular cord-like structures. The Sertoli cells positioned at the base of the cord-like structures were closely connected to the matrigel at their basal surface, and showed a polarized distribution of vimentin filaments in their basal cytoplasm. Leydig cells, on the other hand, were differentiated in all testicular explants. In all ovarian explants, germ cells normally entered meiotic prophase. Therefore, these findings indicate that the extracellular matrix permits testicular differentiation in the absence of the mesonephros, and that removal of mesonephric tissues leads to developmental failure of cord formation because the components of the extracellular matrix around pre-Sertoli cells are incomplete. © 1995 Wiley-Liss, Inc.
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    Masthead (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 32 (1995) 
    Details
    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070320601
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    Development and application of a dry ultramicrotomy technique for the preparation of galvanneal sheet coatings (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 293-299 
    Details
    ISSN: 1059-910X
    Keywords: Sample preparation for ATEM ; PEELS imaging ; Zn-Fe intermetallics characterization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The formability of galvanneal steel sheets used in the automotive industry is influenced by the presence and distribution of brittle and difficult to distinguish Zn-Fe intermetallics in the coating. Characterization of these intermetallics requires a high spatial resolution technique such as analytical transmission electron microscopy (ATEM). Sample preparation by ion milling is impossible due to iron redeposition, and traditional ultramicrotomy using water affects the coating chemistry. A technique based on dry ultramicrotomy has therefore been developed.To optimize the technique, different parameters (knife angle, cutting medium, thickness setting on the ultramicrotome, cutting speed) have been investigated for the preparation of galvanneal coatings and pure Al sections. Results show that dry cutting does not affect the coating chemistry but shortens the life of the knife. Knife quality (cleanliness, sharpness and absence of defects) is a major factor to obtain good dry sections. The best results for the more ductile pure Al are obtained with a 35° knife whilst for the harder galvanneal coating it is recommended to use a 55° knife. These results suggest that the sectioning mechanism for the harder material involves more a cleavage-fracture mechanism whilst a greater amount of shear is involved when sectioning relatively ductile Al. The optimum parameters for sectioning galvanneal coatings are established and results obtained by parallel electron energy loss spectrum imaging and energy dispersive X-ray spectrometry in the TEM are given. This study shows that with a good control of all the sectioning parameters it is possible to obtain good sections repeatedly and rapidly. © 1995 Wiley-Liss, Inc.
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    Electrochemical and microstructural study of oxide films formed electrochemically at microcrystalline al-fe-v-si alloys (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 285-292 
    Details
    ISSN: 1059-910X
    Keywords: Oxide film ; Barrier film ; Ultramicrotomy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A recent advance in metallurgical technology has been the application of rapid solidification techniques to Al alloy production. FVS0812 is the designation given to a microcrystalline Al-based alloy consisting of 8 wt% Fe, 1 wt% V and 2 wt% Si. It is a two-phase alloy, consisting of ca. 27 vol percent of approximately spherical Fe-V-Si-rich dispersoids in an essentially pure Al matrix. The high strength, low density properties of this advanced material, and other related alloys, have not yet been realized, however, due, in part, to the inability of the alloy to form a thick, adherent, abrasion-resistant outer surface oxide film, a feature readily achieved at conventional Al alloys by normal anodizing methods. The present research has involved an electro-chemical study of oxide film growth at the 812 alloy, with the specific goals being to seek an understanding of the origin of the oxide film growth problem and ultimately to propose alternative approaches to the formation of a thick, stable oxide film at this material. The techniques used in this research have included electrochemical methodologies such as cyclic voltammetry and electrochemical impedance spectroscopy. Crucial information has been obtained through transmission electron microscopy (TEM) of ultramicrotomed specimens. Experiments were carried out initially in neutral borate solutions to characterize the compact barrier oxide film formed in this environment and expected to be present beneath the porous oxide film formed in the normal sulfuric acid anodizing medium. In borate solutions, the electrochemical results implied oxide film thicknesses which were less than seen subsequently by TEM work, suggesting either that the barrier film at the 812 alloy can be penetrated by solution in very fine pores (not resolvable by conventional TEM) at its outer surface or that dispersoids trapped in the oxide film cause differential oxide film thicknesses to develop across the alloy surface. In sulfuric acid solutions, dissolution of Fe and V occurs from the 812 alloy during anodization. Both impedance and TEM studies reveal the absence of a barrier film at the 812 alloy surface. Also, the thick oxide overlayer has a tortuous and more open pore structure than formed at Al and the oxide film is also substantially thinner than it should be. It is suggested that the absence of a barrier oxide film indicates that the sulfuric acid anodizing medium is too aggressive for oxide film formation at the 812 alloy, resulting in excessive dissolution and poor oxide film qualities. © 1995 Wiley-Liss, Inc.
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    Ultramicrotomy of diamond films for tem cross-section analysis (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 308-310 
    Details
    ISSN: 1059-910X
    Keywords: Thin films ; TEM specimen preparation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Ultramicrotomy has been used to prepare TEM cross-sections of typical hard dielectric, semiconductor, and metal coatings, providing a critical capability in the study of structure-property relationships of thin films. Ultramicrotomy of thin film coatings requires meticulous attention to technique and handling. The sample to be microtomed must be very small, well bonded to the epoxy embedding medium, and precisely oriented. In this article we report the ability to microtome TEM cross-sections of diamond and cubic boron-nitride (cBN) coatings. © 1995 Wiley-Liss, Inc.
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    Structural and molecular determinants of intercellular coupling in cardiac myocytes (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 357-363 
    Details
    ISSN: 1059-910X
    Keywords: Gap junctions ; Connexins ; Immunofluorescence ; In situ hybridization ; Arrhythmias ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Electrical activation of the heart requires intercellular transfer of current through gap junctions connecting individual cardiac myocytes. Using a combination of light and electron microscopic techniques and molecular approaches, we have characterized the number, size, and spatial distribution of intercellular connections at gap junctions in cardiac myocytes and have also cloned, sequenced, and elucidated the subcellular distribution of three physiologically distinct gap junction channel proteins. In this review, we present evidence to suggest that the spatial distribution of myocyte interconnections and the molecular composition of gap junction channels may confer distinct conduction properties on specific tissues of the mammalian heart such as atrial and ventricular myocardium, and the nodes and bundles of the cardiac conduction system. © 1995 Wiley-Liss, Inc.
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    Myocardial gap junction organization in ischemia and infarction (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 375-386 
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    ISSN: 1059-910X
    Keywords: Gap junctions ; Myocardium ; Ischemia ; Hypoxia ; Freeze fracture ; Immunohistochemistry ; Connexin43 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Ischemia causes an increase in myocardial resistivity and a decrease in conduction velocity, thereby enhancing cardiac contractile dysfunction and arrhythmic tendency. Myocardial gap junctions, as principal determinants of conduction velocity, may, therefore, be expected to be deranged in ischemia. Despite a lack of consensus, attempts at correlating gap junction ultrastructural morphology with functional state have revealed the component connexons of gap junctions in freeze-fractured myocardium to be in multiple small hexagonal arrays, tending to become randomly distributed and compacted under uncoupling conditions. Further hypoxic uncoupling causes ultrastructural damage and a reduction in gap-junctional surface area. Immunohistochemical detection of connexin43 gap junctions in chronically ischemic non-infarcted human myocardium demonstrates a reduction in junctional surface area within a normal number of intercalated disks per myocyte, and with a normal distribution of junction sizes. In healed canine infarction there are smaller and fewer gap junctions in the fibrotic myocardium adjacent to infarcts, with reductions in overall gap-junctional content and the proportion of side-to-side vs. end-to-end intercellular connections. Immunohistochemical examination of intact human ventricular myocardium shows the myocytes immediately abutting healed infarcts to hve connexin43 gap junctions spread longitudinally over the cell surfaces, and not in discrete transversely orienated intercalated disks as in normal myocardium. Early after canine infarction, and before fibrotic healing, the connexin43 gap junctions in myocytes abutting the infarct show disorganization similar to that described in healed human infarcts, suggesting that this disturbance is an early pathophysiological cellular response, and not simply due to later fibrotic distortion. Such changes in gap-junctional organization in myocardial ischemia and infarction may be implicated in the elusive link between subcellular structure, contractile dysfunction and arrhythmogenesis. © 1995 Wiley-Liss, Inc.
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    Gap junctions in blood forming tissues (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 396-407 
    Details
    ISSN: 1059-910X
    Keywords: Gap junction ; Connexin ; Blood ; Haemopoiesis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: More than ten research groups have now reported the presence of gap junctions in blood-forming tissue or cultured cells. It is time to accept that these cell-coupling structures are present in this tissue. To find out what they are doing here we need to develop appropriate experimental techniques. This review covers the particular problems of investigating direct cell-cell communication by gap or other junction in undisturbed haemopoietic tissue. It then describes and assesses the published reports of haemopoietic gap junctions. Recently, in the author's laboratory, three means of increasing the number of gap junctions 50- to 100-fold in mouse marrow have been described, as well as techniques for doing so in culture. There is a complete report of this work here. At present it is quite unclear what function gap junctions serve in blood-formation, perhaps it is some consolation that 30 years after their ultramicroscopic discovery it is also true for all other unexcitable tissues. Possibly the ability to up-regulate their expression in haemopoietic tissue will help us find out what their role is in blood formation. © 1995 Wiley-Liss, Inc.
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    Gap junctions revealed by freeze-fracture electron microscopy (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 437-445 
    Details
    ISSN: 1059-910X
    Keywords: Intramembrane particle plaques ; Surface distribution ; Experimental manipulation ; Junction neogenesis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Gap junctions provide the basis for the formation of elaborate networks of communication between cells in animal tissues. Electron microscopic examination of thin sections of plastic embedded gap junctions has provided valuable information on the anatomy and function of these remarkable structures. Freeze-fracture electron microscopy, however, has made available unique vistas of gap junction-bearing intramembrane surface-surface previously inaccessible to the researcher's eyes. Data on population density, distribution, size, geometry of intramembrane particle packing, and structural responses of gap junction components to experimental manipulation are simply and easily obtained with freeze fracture. Recent developments of sophisticated protocols of immunocytochemistry as applied to freeze-fracture replicas further serve to reinforce the notion that freeze-fracture is a powerful tool for study of gap junctions. Molecular techniques of gap junction gene transfection promise to add a truly unique dimension to investigations of the broad spectrum of functional roles of gap junctions. © 1995 Wiley-Liss, Inc.
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    Spatial organization of cardiac gap junctions can affect access resistance (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 446-451 
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    ISSN: 1059-910X
    Keywords: Freeze-fracture ; Confocal microscopy ; Gap junction channels ; Mathematical analytical model ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: In the heart, gap junctions electrically couple myocytes together. Electron- and light-microscope-based analyses have revealed that cardiac gap junctions show a variety of organizational patterns. At the level of gap-junctional channel aggregates, freeze fracture has demonstrated diverse channel packing arrangements in the membranes of different myocardial tissues. Ultrastructural and immunohistochemical studies have shown variation and specialization in the 3-dimensional spatial distribution of gap junctional contacts between different types of myocardial cells. Here, we estimate the access resistance of various configurations of gap junctions using physical principles and explore how certain of these specializations in gap-junctional organization may influence access resistance, a potentially important determinant of electrical conductance between coupled myocardial cells. © 1995 Wiley-Liss, Inc.
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    Masthead (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 20 (1992) 
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    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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    URL: http://dx.doi.org/10.1002/jemt.1070200101
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    Editorial (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 20 (1992), S. 1-1 
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    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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    URL: http://dx.doi.org/10.1002/jemt.1070200102
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    A personal computer based implementation of the maximum-likelihood method of analysis of electron microscope autoradiographs (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 20 (1992), S. 73-86 
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    ISSN: 1059-910X
    Keywords: Electron microscopy ; Autoradiography ; Maximum-likelihood estimation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The maximum-likelihood (ML) method for the quantitative analysis of electron-microscopic autoradiographs has been shown to be substantially superior to the conventional crossfire (CF) method. It can generate reliable and accurate tracer concentration estimates with far fewer micrographs and produce valid estimates even at counts low enough to preclude the use of the crossfire method while eliminating the need for special ad hoc treatment of narrow membranous structures as well as the secondary verification of the tracer concentration estimates.Despite these significant advantages, the large computational requirements of the ML method has to date hampered its widespread use. In this paper, we present a new line-integration method that allows us to reduce the computational requirements of the ML method to a point where it becomes feasible to implement it on a small computer system of the type typically available to a laboratory user of EM autoradiography. We present the complete line-integration method for the particular case of EM autoradiography with tritium, and show how it can be adapted to other isotopes.We have constructed a software package that implements the complete maximum-likelihood method on the IBM PC class of machines using our line-integration method. Features of this software package which are of particular importance to the research community are device independence, which makes it usable with a large variety of currently available laboratory equipment, and easy portability of the software and data between different computer systems.
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    Utilization of electron microscopic techniques in the in vitro study of adenohypophysial function and regulation (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 20 (1992), S. 136-151 
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    ISSN: 1059-910X
    Keywords: Pituitary ; Adenomas ; Tissue culture ; Ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Morphologic studies of human adenohypophysial cells using immunocytochemistry and electron microscopy have characterized the hormone-producing cell types of the normal gland and pituitary adenomas. The classifications which have emerged allow more accurate clinicopathologic correlations than ever before, but have also raised new questions concerning cytogenesis, pathogenesis, and structure-function correlations. We report the results of studies which marry the conventional morphologic techniques of light microscopy, immunohistochemistry, electron microscopy, and ultrastructural immunocytology with functional analyses using tissue culture and radioimmunoassay of hormones released into culture media. The hormone secretory activity of nontumorous and adenomatous pituitary cells is correlated with their structural features; their secretory responses to several adenohypophysiotropic factors are compared with morphologic alterations which are characterized at the light and electron microscopic levels by morphometric analysis. These studies have shown that hypothalamic stimulating hormones increase hormone release by their target cells and alter the ultrastructural appearance of the affected cells by increasing organelles involved in hormone synthesis. Inhibitory drugs and adrenal and gonadal steroids are capable of suppressing hormone release by some tumors and also give rise to morphologic changes which correlate with the functional inhibition. Hormone release by clinically nonfunctioning adenomas has been characterized and the behavior of these tumor cells in vitro sheds some light on the reasons for lack of clinical symptomatology. The plurihormonal nature of several nontumorous and adenomatous pituitary cell types has been characterized in vitro. The results of these studies provide the basis for more accurate structure-function correlations which can be used to study the hormonal milieu in vivo, to predict the role of pathogenetic factors in pituitary tumorigenesis, and to assess the therapeutic value of stimulating or inhibiting hormones and drugs.
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    Cell lineage in molluscan development (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992), S. 75-102 
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    ISSN: 1059-910X
    Keywords: Egg ; Polarity ; Morphogenetic plasm ; Cell communication ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Cell lineage specification in molluscs is brought about by two mechanisms: the segregation of morphogenetic plasms and inductive cell interactions. The evidence for the existence of morphogenetic plasms is largely circumstantial, but in one species, Bithynia, such a plasm has been identified in the polar lobe that forms at first cleavage. Inductive cell interactions are thought to be a prerequisite for the development of a large number of tissues and organs. The most extensively studied example is the specification of the mesodermal stem cell in Lymnaea and Patella, which occurs between 5th and 6th cleavage through an interaction between one macromere and a large number of micromeres.Both segregation and induction are tuned to the animal-vegetal polarity of the egg, at least during early development. This polarity probably arises during oogenesis and is manifest in regional differentiations of the surface architecture of the egg, in the distribution of inner membrane particles in the plasma membrane, in membrane fluidity characteristics, in ionic conductance properties of the plasma membrane, etc. All these phenomena have in common that they represent properties of the egg surface, suggesting that the polarity of the egg is somehow imprinted into the plasma membrane and the cortex of the egg during oogenesis. © 1992 Wiley-Liss, Inc.
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    Role of ultrastructural studies in the analysis of cell lineage in the mammalian pre-implantation embryo (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992), S. 103-125 
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    ISSN: 1059-910X
    Keywords: Cell lineage analysis ; Mammalian embryo ; Ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Ultrastructural studies have contributed significantly to our understanding of cell lineage differentiation in the mammalian pre-implantation embryo. Such studies have documented, and continue to document, morphological, biochemical, and physiological characteristics of the cell lineages established during the pre-implantation period in eutherian embryos, principally that of the mouse. This review evaluates these contributions and identifies areas of study in which ultrastructural analysis is most likely to have an important role in the future. © 1992 Wiley-Liss, Inc.
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    Ultrastructural imaging of freeze-fractured plant cells in the scanning electron microscope (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992), S. 160-169 
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    ISSN: 1059-910X
    Keywords: Freeze-fracture and cytoplasmic maceration ; Chloroplasts ; Pollen ontogeny ; SEM ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The application of the freeze-fracture and cytoplasmic maceration technique in ultrastructural studies of plant cells is described. A major advantage of the technique is, that by extracting mobile cytoplasmic components from the freeze-fractured cells, surface relief is introduced and three-dimensional information is obtainable. The details of specimen preparation are described and the results obtained are reviewed. The use of chitosan embedding for very small or fragile specimens is described. © 1992 Wiley-Liss, Inc.
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    Preservation and visualization of molecular structure in detergent-extracted whole mounts of cultured cells (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992), S. 130-150 
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    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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    Comparative study of ion milling techniques in cross-sectional transmission electron microscope specimen preparation (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992), S. 199-206 
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    ISSN: 1059-910X
    Keywords: VLSIC ; XTEM ; Semiconductor industry ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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    Masthead (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992) 
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    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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    URL: http://dx.doi.org/10.1002/jemt.1070220301
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    Preparation of aqueous standards for low temperature x-ray microanalysis (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992), S. 207-211 
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    ISSN: 1059-910X
    Keywords: Quantitative low temperature X-ray microanalysis ; Homogeneous dispersion in ice ; Aqueous standards ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A technique, using Nuclepore polycarbonate membrane filters as a containing medium for very small volumes of ionic standard solutions, to produce homogeneous ice standards is described. The standards are suitable for use in a scanning electron microscope. The relationship between elemental X-ray counts and ionic concentration is found to be linear. The method is rapid and simple. Minimum detectable concentrations are given. © 1992 Wiley-Liss, Inc.
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    Suspected chemoreceptors in coelenterates and ctenophores (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992), S. 265-284 
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    ISSN: 1059-910X
    Keywords: Battery cell ; Cnidocil ; Cnidocyte ; Kinocilium ; Onion-root body ; Nematocyst ; Sensory cell ; Stereocilia ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Chemoreceptors in coelenterates and ctenophores have not been identified with certainty. Among prospective chemoreceptive cells are the sensory nerve cells, the cnidocyst bearing cnidocytes, and the epitheliomuscular cells that are likely to be involved in feeding or aggression. Both behaviors are mediated by coordinated chemical and mechanical reception. This is reflected in the close apposition of putative chemo- and mechanoreceptors. Among the structures that have been designated as likely chemo- and/or mechanoreceptors are stereocilia, kinocilia, and/or microvilli which are universally present on all the putative chemoreceptor complexes, while gland cells and mucous secretions are prevalent. Evidence that the actin-containing stereocilia are chemically modulated mechanoreceptors is presented for several forms. © 1992 Wiley-Liss, Inc.
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    Cortical ultrastructure and chemoreception in ciliated protists (ciliophora) (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992), S. 225-264 
    Details
    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The ciliated protists (ciliates) offer a unique opportunity to explore the relationship between chemoreception and cell structure. Ciliates resemble chemosensory neurons in their responses to stimuli and presence of cilia. Ciliates have highly patterned surfaces that should permit precise localization of chemoreceptors in relation to effector organelles. Furthermore, ciliates are easy to grow and to manipulate genetically; they can also be readily studied biochemically and by electrophysiological techniques. This review contains a comparative description of the ultrastructural features of the ciliate cell surface relevant to chemoreception, examines the structural features of putative chemoreceptive cilia, and provides a summary of the electron microscopic information available so far bearing on chemoreceptive aspects of swimming, feeding, excretion, endocytosis, and sexual responses of ciliates. The electron microscopic identification and localization of specific chemoreceptive macromolecules and organelles at the molecular level have not yet been achieved in ciliates. These await the development of specific probes for chemoreceptor and transduction macromolecules. Nevertheless, the electron microscope has provided a wealth of information about the surface features of clliates where chemoreception is believed to take place. Such morphological information will prove essential to a complete understanding of reception and transduction at the molecular level. In the ciliates, major questions to be answered relate to the apportionment of chemoreceptive functions between the cilia and cell soma, the global distribution of receptors in relation to the anterior-posterior, dorsal-ventral, and left-right axes of the cell, and the relationship of receptors to ultrastructural components of the cell coat, cell membrane, and cytoskeleton. © 1992 Wiley-Liss, Inc.
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    A method for rapidly collecting serial sections for light microscopy (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992), S. 306-306 
    Details
    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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    URL: http://dx.doi.org/10.1002/jemt.1070220309
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    Morphology of olfactory epithelium in humans and other vertebrates (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 23 (1992), S. 49-61 
    Details
    ISSN: 1059-910X
    Keywords: Olfactory neuron ; Neurogenesis ; Plasticity ; Electron Microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Human olfactory epithelium is similar in organization and cell morphology to that of most vertebrate species. The epithelium has a pseudostratified columnar organization and consists of olfactory neurons, supporting and basal cells. Near the mucosal surface there are also microvillar cells. These cells have neuron-like features and may be chemoreceptors. Human olfactory epithelium is not a uniform sensory sheet. Patches of non-sensory tissue often appear in what was thought to be a purely olfactory region. The significance of these patches has not been determined, but they could reflect exposure to environment agents or changes that occur during the normal aging process.In order to better understand the human olfactory system, further knowledge of the normal structure is necessary. This review addresses the morphology of the human olfactory epithelium and the remarkable plasticity of the vertebrate olfactory system. © 1992 Wiley-Liss, Inc.
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    Olfactory epithelium in young adult and aging rats as seen with high-resolution scanning electron microscopy (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 23 (1992), S. 62-75 
    Details
    ISSN: 1059-910X
    Keywords: Olfactory receptor cell ; Supporting cell ; Ultrastructure ; Lipofuscin granules ; Golgi apparatus ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The present study uses mainly scanning electron microscopy to demonstrate the three-dimensional internal cell structures of rat olfactory epithelial cells. The aldehyde-prefixed osmium-DMSO-osmium (AODO) method devised by Tanaka and Mitsushima (1984) was applied to the present study to disclose intracellular structures such as endoplasmic reticulum, mitochondria, Golgi apparatus, and lysosomes. The spatial distribution pattern of these structures in olfactory and supporting cells is discussed, paying special attention to the formation of lipofuscin-like granules present in aged rats. © 1992 Wiley-Liss, Inc.
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    The thickness determination of organic crystals under low dose conditions using electron energy loss spectroscopy (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 21 (1992), S. 166-170 
    Details
    ISSN: 1059-910X
    Keywords: Protein crystals ; Crystal thickness ; Paraffin crystals ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: In the 3-dimensional (3-D) reconstruction of protein crystals with variable thicknesses the electron images and diffraction patterns can only be merged if the crystal thickness is known. Measurement of the thickness using the ratio of the number of inelastically scattered electrons to the number of electrons in the zero loss peak can be accomplished with parallel electron energy loss spectrometry (PEELS). A theoretical analysis of the accuracy of the technique on paraffin crystals of different thicknesses is presented. Our experimental studies with paraffin crystals show the feasibility of measuring a single layer of 47 Å with good accuracy under low dose and low temperature conditions. A simple experimental apparatus is proposed to obtain thicknesses from small regions of unstained protein crystals prior to collecting the 3-D data sets from the unexposed area of the same crystal.
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    URL: http://dx.doi.org/10.1002/jemt.1070210208
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    Background correction of intensifier camera images in the T.E.M. (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 21 (1992), S. 171-173 
    Details
    ISSN: 1059-910X
    Keywords: Transmission Electron Microscope ; Light Intensifier Camera ; Microscopy ; Background correction ; Image Analysis ; Video Microscopy ; Television Camera ; Frame Store ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Several disadvantages of using intensified television cameras to acquire TEM images can be overcome by using background subtraction with a frame store.
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    Ab-initio primitive cell parameters from single convergent-beam electron diffraction patterns: A converse route to the identification of microcrystals with electrons (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 21 (1992), S. 158-165 
    Details
    ISSN: 1059-910X
    Keywords: Least squares refinement ; X-ray analysis ; Cell parameters ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A new method for the ab initio derivation of Buerger-reduced primitive cell parameters from coordinate measurements of spots on single convergent-beam electron diffraction (CBED) patterns is described, which does not involve trial-and-error. The pattern can be taken along any zone axis, and misorientations of the crystallite by as much as a few degrees are taken into account without loss of accuracy. This derivation of cell parameters by least-squares analysis of the measurements has been automated in a program called NRCBED. Present accuracy is about 1% on lengths and 2° on angles, but could be significantly improved by modelling projector lens aberrations, or by using a microscope without a projector lens. With present technology, it is possible to obtain a CBED pattern and a semi-quantitative energy-dispersive X-ray (EDX) analysis simultaneously from a single microcrystal a few hundred Ångströms across. It becomes therefore possible to identify the material of the crystal on a single CBED pattern: a cell parameter database for known compounds is searched with the primitive cell parameters obtained in the above way, and with a mask describing the EDX results qualitatively. Feasibility is demonstrated on a crystallite of CeO2 500 Ångströms across. With this new approach, trial-and-error should disappear from the solution of other long-standing problems: interpretation of X-ray powder patterns for new compounds in the presence of impurity lines, or in the case of multiple phases should become straightforward.
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    URL: http://dx.doi.org/10.1002/jemt.1070210207
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    Masthead (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 21 (1992) 
    Details
    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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    URL: http://dx.doi.org/10.1002/jemt.1070210301
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    Observation of atomic steps on single crystal surfaces by a commercial scanning electron microscope (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 20 (1992), S. 406-412 
    Details
    ISSN: 1059-910X
    Keywords: REM ; Contrast mechanism ; Imaging technique ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Atomic steps on (111) and (100) crystal surfaces of Pt were observed using a commercial scanning electron microscope (SEM) in secondary electron mode. By comparing the SEM images and those by reflection electron microscopy (REM), the observed contrast was confirmed to be that from atomic steps on crystal surfaces. The contrast mechanism is briefly discussed. One application of this imaging technique is also shown.
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    Observation of double line contrast in surface imaging (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 20 (1992), S. 413-425 
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    ISSN: 1059-910X
    Keywords: REM ; RHEED ; Surface resonance condition ; Contrast splitting ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The double line contrast of a single-atom height step observed in surface imaging for a single crystal in reflection electron microscopy is studied under a variety of experimental conditions. It is suggested that this abnormal contrast is directly associated with the dynamical electron diffraction process. The behavior of the double line contrast is closely related to the order of the Bragg reflected beam, and can be observed mostly under one of the two commonly cited resonance conditions. This phenomenon clearly reveals the differences in the surface imaging for various resonance conditions.
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    Preparation and characterization of MgO surfaces by reflection electron microscopy (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 20 (1992), S. 426-438 
    Details
    ISSN: 1059-910X
    Keywords: Reflection high energy electron diffraction ; Surface topography ; Chemical polishing ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: We have employed several different methods to prepare (100) and (111) surfaces of MgO crystals. (100) surfaces prepared by simple cleaving give good reflection high energy electron diffraction (RHEED) patterns and surfaces with a high density of coarse steps. Chemical polishing of this surface results in a roughening of the topography whilst annealing in oxygen considerably smoothens the surfaces although they appear to be contaminated. Under certain conditions we find that the MgO crystals will cleave along the (111) plane. Both cleaved and mechanically polished (111) surfaces are atomically flat and reconstructed after oxygen annealing.
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    Ciliated and microvillar receptor cells degenerate and then differentiate in the olfactory epithelium of rainbow trout following olfactory nerve section (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 23 (1992), S. 22-27 
    Details
    ISSN: 1059-910X
    Keywords: Plasticity ; Retrograde degeneration ; Ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: We used scanning (SEM) and transmission (TEM) electron microscopy to examine ultrastructural changes in the olfactory epithelium (OE) of rainbow trout following unilateral olfactory nerve section. Both ciliated receptor cells (CRC) and microvillar receptor cells (MRC) degenerated and subsequently differentiated from unidentified precursor cells. The following changes took place in fish that were held at 10°C at the stated period following olfactory nerve section: on day 7, MRC and CRC contained intracellular vacuoles; on day 12, the olfactory knobs appeared disrupted; by day 26, olfactory receptor cells were absent from the OE; on day 42, there were receptor cell bodies and a few CRC with short cilia at the apical surface; and opn day 55, a small number of both CRC and MRC had differentiated. By day 76, both CRC and MRC repopulated the OE. Degenerative changes in the cytoplasm of the sustentacular cells (SC) and ciliated nonsensory cells (CNC) were observed in the first 26 days following olfactory nerve section, but these cells remained intact throughout the experiment. The degeneration and subsequent differentiation of CRC and MRC supports and extends previous observations that both cells types are olfactory receptor neurons with axons that extend along the olfactory nerve to the olfactory bulb. © 1992 Wiley-Liss, Inc.
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    Ultrastructural neurobiology of the olfactory mucosa of the brown trout, Salmo trutta (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 23 (1992), S. 28-48 
    Details
    ISSN: 1059-910X
    Keywords: Nose ; Olfaction ; Ultrastructure ; Toxicology ; Smell ; Sensory ; Fish ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: This paper describes four investigations of the olfactory mucosa of the brown trout: 1) the ultrastructure of the olfactory mucosa as revealed by scanning (SEM), conventional transmission (TEM), and high voltage (HVEM) electron microscopy; 2) light and electron-microscopic investigations of retrograde transport of the tracer macromolecule horseradish peroxidase (HRP) when applied to the cut olfactory nerve; 3) SEM and TEM investigations of the effects of olfactory nerve transection on cell populations within the olfactory epithelium; and 4) ultrastructural investigations of reversible degeneration of olfactery receptors caused by elevated copper concentrations. The trout lofactory epithelium contains five cell types: ciliated epithelial cells, ciliated olfactory receptor cells, microvillar olfactory receptor cells, supporting cells, and basal cells. The ciliated and microvillar olfactory receptor cells and a small number of basal cells are backfilled by HRP when the tracer is applied to the cut olfactory nerve. When the olfactory nerve is cut, both ciliated and microvillar olfactory receptor cells degenerate within 2 days and are morphologically intact again within 8 days. When wild trout are taken from their native stream and placed in tanks with elevated copper concentrations, ciliated and microvillar cells degenerate. Replacement of these trout into their stream of origin is followed by morphologic restoration of both types of olfactory receptor cells. Ciliated and microvillar receptor cells are primary sensory bipolar neurons whose dendrites make contact with the environment; their axons travel directly to the brain. Consequently, substances can be transported directly from the environment into the brain via these “naked neurons.” Since fish cannot escape from the water in which they swim, and since that water may occasionally contain brain-toxic substances, the ability to close off - and later reopen - this anatomic gateway to the brain would confer a tremendous selective advantage upon animals that evolved the “brain-sparing” capacity to do so. Consequently, the unique regenerative powers of vertebrate olfactory receptor neurons may have their evolutionary origin in fishes. © 1992 Wiley-Liss, Inc.
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    Use of ferrofluids to obtain magnetic domain images in afm (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 23 (1992), S. 98-99 
    Details
    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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    URL: http://dx.doi.org/10.1002/jemt.1070230109
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    Elimination of artifactual labeling of hippocampal mossy fibers seen follong pre-embedding immunogold-silver technique by pretreatment with zinc chelator (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 23 (1992), S. 100-101 
    Details
    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Additional Material: 1 Ill.
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    Flat embedding and immunolabelling of SW 1116 colon carcinoma cells in LR white: An improved technique in light and electron microscopy (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 21 (1992), S. 1-9 
    Details
    ISSN: 1059-910X
    Keywords: Mucin ; Immunofluorescence ; Immunoelectron microscopy ; Monoclonal antibody 19-9 ; Matrigel ; PAS stain ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Human SW 1116 colon carcinoma cells were grown on matrix-covered coverslips and flat embedded in specially prepared gelatin capsules in the hydrophylic resin LR White. Dehydration and polymerization were carried out so as to maximize preservation of antigenicity. Sections were cut perpendicular to the substratum. To visualize mucin, semithin sections of SW 1116 cells were stained with periodic acid Schiff (PAS) reagent for light microscopy, and ultrathin sections were labelled with a monoclonal mucin antibody (Mab 19-9) and immunogold for electron microscopy. Immunofluorescence was carried out on whole cultured cells using Mab 19-9. The morphological preservation of SW 1116 cells embedded in LR White was comparable to that of Epon-embedded cells. Mucin was localized on the microvillar surface of the apical plasma membrane and occasionally in intercellular spaces between adjacent cells. Mucin was also present in vesicles in the apical and lateral part, and to a lesser extent in the basal part of the cells. We conclude that this new technology significantly improves the morphological preservation of cells and tissues in LR White, while also serving to sustain the antigenicity of cellular antigens.
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    Scanning electron microscopy of negatively stained catalase on a silicon wafer (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 21 (1992), S. 32-38 
    Details
    ISSN: 1059-910X
    Keywords: High-resolution scanning electron microscope (HRSEM) ; Negative staining ; Surface ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A high-resolution scanning electron microscope capable of 7 Å spatial resolution at 30-kV accelerating voltage was used to observe negatively stained protein molecules. Thin platelet crystals, densely packed monolayers, and low-density deposits of beef liver catalase were prepared on the surface of silicon wafers and negatively stained with phosphotungstic acid. The tetrameric structure of the catalase molecule was observed for the first time by scanning electron microscopy on the surface of the smooth silicon wafer.
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    Sequential observations followed by acid etching on the enamel surfaces of human teeth under scanning electron microscopy at low vacuum (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 24 (1993), S. 429-436 
    Details
    ISSN: 1059-910X
    Keywords: Low vacuum specimen chamber ; No dehydration ; No coatings ; Backscattered electrons ; Enamel structures ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A scanning electron microscope equipped with a low vacuum specimen chamber and a Robinson's backscattered electron detector was employed to observe the natural surfaces of human buccal enamel before and after 30 percent phosphoric acid etching sequentially up to 90 sec at the same sites with no coatings. Furthermore, successive etching patterns were compared between deciduous and permanent teeth. On the imbrication lines of young permanent teeth, prismend pits surrounded with a “prismless” structure occasionally disappeared after acid etching and became a prismless enamel. Sequential etching caused the prismless areas and the areas of a type 1 etching pattern to decrease, and a cone-shaped prism structure and a complex type of the type 1 and type 2 etching pattern (type 1-2) to appear. The former was a transitional type between the prismless enamel and type 2 prisms. These etched surfaces show type 2 prisms after deeper etching. Small dome-shaped structures, slightly elevated on the attrited enamel surfaces, were found only in deciduous teeth. After acid etching, such areas which retained the prismless enamel rose to the underlying surfaces of cone-shaped prisms. © 1993 Wiley-Liss, Inc.
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    Preservation of antigenic reactivity after cryofixation, cryosubstitution, and cryoembedding in Lowicryl HM23: Application to alcohol dehydrogenase in Drosophila fat body (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 24 (1993), S. 453-454 
    Details
    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Additional Material: 1 Ill.
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    Masthead (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 24 (1993) 
    Details
    ISSN: 1059-910X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070240601
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    Application of cryotechniques in cartilage tissue preservation an immunoelectron microscopy: Potentials and problems (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 24 (1993), S. 457-464 
    Details
    ISSN: 1059-910X
    Keywords: Cartilage ; Proteoglycans ; Collagen ; Structure ; Freeze substitution ; Immunohistochemistry ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Cryotechnical processing of cartilage has the potential to solve many of the tissuespecific problems associated with various routine chemical fixation protocols. This is particularly the case with respect to extracellular matrix architecture, the distortion or destruction of which (caused by extraction and/or precipitation of proteoglycan molecules) may be prevented. Adoption of such techniques also permits high-sensitivity immunoelectron-microscopy of the extracellular matrix space (carbohydrate epitopes). However, a number of difficulties still remain to be resolved, particularly that of matrix-cell interface separation occurring during freeze substitution and low temperature embedding. These problems are briefly addressed and possible solutions outlined. © 1993 Wiley-Liss, Inc.
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    Improved preservation of ultrastructure in difficult-to-fix organisms by high pressure freezing and freeze substitution: I. Drosophila melanogaster and Strongylocentrotus purpuratus embryos (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 24 (1993), S. 465-473 
    Details
    ISSN: 1059-910X
    Keywords: High pressure freezing ; Freeze substitution ; Drosophila ; Sea urchin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: In this study, we have applied the techniques of high pressure freezing and freeze substitution to embryonic cell types which are usually difficult to fix properly for electron microscopy. In both Drosophila and Strongylocentrotus purpuratus, we see improved preservation of both membrane systems and cytoskeleton when compared to published results on the same cells using conventional electron microscope (EM) fixation methods. Finally, we have seen that postembedding labelling of sections is possible even after light osmium fixation during freeze substitution. © 1993 Wiley-Liss, Inc.
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    Freeze substitution after fast-freeze fixation in preparation for immunocytochemistry (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 24 (1993), S. 474-487 
    Details
    ISSN: 1059-910X
    Keywords: Immunogold labeling ; Antigenic preservation ; Bioluminescence ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: As compared to classical chemical fixation, the physical immobilization of ultrastructures by fast-freeze fixation (FFF) and the subsequent exchange of water in its solid state by freeze substitution (FS) improve the preparation procedure for immunogold labeling (IGL).FFF-FS results in a morphological preservation of unchallenged quality, as well as in a better preservation of antigenic reactivity, thus allowing remarkable precision of labeling on sections.However, FFF, particularly over a cooled metal plate, requires a heavy and expensive machine. It is not suitable for all biological specimens and in the best conditions, which remain difficult to standardize, the thickness of the well-preserved portion of the specimen does not exceed a few μm for compact tissues, and exceptionally 30-40 μm for isolated cells.The FS procedure is long and must be adjusted empirically for every new specimen and antigenic detection. The preservation of a given antigen's reactivity in the presence of fixative agents and embedding resins remains unpredictable. The action of fixative agents is different and milder in FS than when they are used classically in chemical fixation. By chance, one of the best FS procedures for the preservation of both ultrastructure and antigenicity appears to be by using acetone alone, together with a molecular sieve to improve the water exchange process. A large choice of embedding resins usually allows us to find a compromise between ultrastructural and antigenic preservation. © 1993 Wiley-Liss, Inc.
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    Freeze-Substitution for morphological and immunocytochemical studies in insects (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 24 (1993), S. 488-504 
    Details
    ISSN: 1059-910X
    Keywords: Cryofixation ; Cryosubstitution ; Olfactory sensilla ; Thermo-/hygroreceptive sensilla ; Pheromone-binding protein ; Bombyx mori ; Antheraea polyphemus ; Poecilocampa populi ; Boreus hiemalis ; Drosophila melanogaster ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Methods of plunge freezing and freeze-substitution (FS) for insect antennae and similar body appendages are described. In these more or less cylindrical specimens, usually a layer below the cuticular surface of 10-15 μm thickness is well preserved without freezing damage, further inwards ice-crystal ghosts of increasing size are encountered, but in the very centre of antennal branches (diameter ∼80 μm) of the silkmoth, Bombyx mori, freezing damage is usually reduced again. The frost-hardy species, Poecilocampa populi and Boreus hiemalis, exhibit regions free from freezing damage up to 40 μm below the cuticular surface. Secondary freezing damage in silkmoth sensory hairs is observed only after deliberately warming the specimens to -43°C for 〉〉10 min before FS. Secondary artefacts due to the substitution process are investigated by comparison with freeze-etching and by comparing different FS media and protocols. Methanol is not recommended as a substitution medium for insect specimens. Structures particularly liable to substitution damage are the stimulus-conducting pore tubules of olfactory sensilla and the receptor cell membrane. Extraction of soluble components is more likely with pure organic solvents without added chemical fixing agents and with prolonged substitution at elevated temperatures. Such extraction may also be a possible artefact with soluble antigens in immunocytochemical studies. A review is given of the major achievements attained with these techniques in insect functional morphology and immunocytochemistry. © 1993 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070240605
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  • 98
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    Discrepancies in kinematic calculations of HOLZ lines (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 24 (1993), S. 509-513 
    Details
    ISSN: 1059-910X
    Keywords: Convergent-beam diffraction ; Lattice parameter ; Computer simulation ; Electron wavelength ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: We have found significant differences between the results of computer simulations of HOLZ line patterns. The computations in question are made in the kinematical approximation. After trivial errors are eliminated the programs fall into two groups. There is a discrepancy between the two that increases with distance from the zone axis. The difference is small but not negligible at the level of precision used in determining lattice parameters or strain.We show which of the two is correct in the kinematic approximation and that the discrepancy between the two groups is of the order of the error introduced by dynamical interaction. © 1993 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070240607
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  • 99
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    Electronic Resource
    Morphometric evaluation of populations of neuronal profiles (cell bodies, dendrites, and nerve terminals) in the central nervous system (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 21 (1992), S. 315-337 
    Details
    ISSN: 1059-910X
    Keywords: Computer-assisted image analysis ; Morphometric methods ; Cell clusters ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Morphometric techniques have been developed to quantitatively characterize groups of transmitter-identified neuronal profiles, such as cell groups, dendrite and nerve terminal fields. These morphometric techniques will be illustrated by introducing some general tools for image analysis which can be considered as a background for the present specific applications. The following methods have been included: (1) methods to identify and quantitatively characterize, from both numerical and geometrical standpoints, groups of profiles in a two- and three-dimen-sional frame; (2) methods to evaluate the evenness of a certain distribution of profiles in the plane; (3) methods to identify subgroups of profiles based on their different spatial or optical density; and (4) methods to compare the distributions of two or more groups of profiles. The applications of these general tools to some neuroanatomical problems, such as cell group definition and description, have been illustrated. Practical examples performed on immunocytochemical preparations of neuronal profile populations are also given. Finally, the potentiality of numerical classification to classify and compare morphometric data has been shown. As an example, numerical classification methods have been applied to the morphometric and microdensitometric analysis of adrenaline/neuropeptide Y costoring neuronal systems of the brainstem in adult and aged rats. © 1992 Wiley-Liss, Inc.
    Additional Material: 26 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070210408
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  • 100
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    Electronic Resource
    Quantitative morphology for biologists and computer scientists: I. Computer-aided tutorial for biological stereology (version 1.0) (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 21 (1992), S. 338-346 
    Details
    ISSN: 1059-910X
    Keywords: Tutorial ; Electron microscopy ; Light microscopy ; Software ; Quantitative morphology ; Stereology ; Morphometry ; Simulations ; Terminology ; Data types ; Sampling ; Hierarchies ; Interpretation of data ; Bio-Matrix Project ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: This paper describes a computer-aided tutorial for biological stereology. Stereology, a type of quantitative morphology, includes a collection of statistical methods that quantify the structural compartments that can be viewed in sections with light and electron microscopy. These methods provide volume, surface, length, shape, and number data, and help define the quantitative relationships among the structural compartments of biological hierarchies. Hierarchies, which connect structural data ranging in size from molecules to organs, serve as a central core to which the data of biological databases can be linked. The tutorial focuses on two objectives. It provides the user primarily interested in using quantitative morphology databases with background information, and offers a set of state-of-the-art tools to researchers wishing to use these methods in the laboratory. The main topics of the tutorial include: introduction to quantitative morphology, symbols/terms, data types, sampling, hierarchies, data interpretation, and utilities. The tutorial runs under the MS-DOS operating system and requires at least an IBM PC AT (or compatible), a color monitor (EGA, VGA), 540 KB of RAM, and 3 MB of hard disk space. © 1992 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070210409
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