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  • 1
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985), S. 73-87 
    ISSN: 0741-0581
    Keywords: Response function ; Gradient ; Acutance ; Laplacian ; Edge sharpening ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Based on the information transmission theory, topographic image signals in scanning electron microscopy are used to evaluate contrast, gradient, acutance, and Laplacian operator, the total of which represent the image sharpness of an edge line.One may consider the impulse and step functions as an input to the Gaussian system function of a low-pass filter, the impulse and step response functions possibly representing a single spot and image contrast of an edge profile, respectively. It is shown that the response function of acutance defined as the power of the gradient normalized by density is a more realistic representation of image edge sharpness. Also, edge sharpness can be greatly enhanced by utilizing the Laplacian operator through digital image processing for a disk specimen model with a rounded edge.Contrast increased by specimen tilt, and an edge effect due to side-scattered electrons, as well as the signal attenuation by specimen collection, are consistently obtained as the response function in the system.The exact measurement of spot size and edge-to-edge resolution, and image sharpness improvement, are derived by digital image processing.
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  • 3
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    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985), S. 157-160 
    ISSN: 0741-0581
    Keywords: Ultramicrotome ; sectioning ; MT-1 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A Dupont-Sorvall MT-1 ultramicrotome, normally a manually operated instrument, was equipped with a small motor. Ultrathin sections were successfully cut at rates from one to five sections per minute. This lowcost conversion to automatic operation offers an alternative to the purchase of a new ultramicrotome, as well as making a classic instrument more flexible.
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  • 4
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    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985) 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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  • 5
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985), S. 167-169 
    ISSN: 0741-0581
    Keywords: Electron microscopy ; EELS ; feedback system ; peak stabilization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The position of the zero-loss peak in electron energy-loss spectra was sensed with a double photo diode. A signal, proportional to the disturbances from a central position, was amplified and fed back into a deflection coil in order to compensate for the origin of the disturbances. Thus, slow variations of the position of characteristic edges in the EEL spectrum could be reduced by a factor 100, and 60 Hz oscillations could be reduced by a factor 5.
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  • 6
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985), S. 201-208 
    ISSN: 0741-0581
    Keywords: SEM ; Rapid freezing ; Osmium ; Dimethyl sulfoxide ; Intracellular structure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A combined technique of the rapid freezing, freeze substitution-fixation method and the osmium-DMSO-osmium method was devised. By this combined method we clearly observed the architecture of intracellular components in three dimensions. Morphological characteristics were generally similar to those of tissue prepared by the osmium-DMSO-osmium method but different in some respects. Mucigen droplets in intestinal goblet cells, for example, appeared as separated spheres, while in specimens prepared by chemical fixation they were observed as a mass of fused droplets. In the Golgi complex, all cisternae were extremely flat, although they usually dilated on the cis side after chemical fixation. Particles on the mitochondrial tubules of liver cells were well distinguished. They were mushroom shaped, as are those observed by negative staining. The combined method, that is, the rapid freezing, osmium-DMSO-osmium method, is thought to be effective for studying the true structure of intracellular components by scanning electron microscopy.
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  • 7
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985), S. 209-215 
    ISSN: 0741-0581
    Keywords: Lung mineral dust ; scanning electron microscopy ; x-ray energy dispersive spectrometry ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Following Na-hypochlorite digestion of lung tissue, mineral particles extracted in the chloroform layer were deposited directly on a pre-smoothed carbon planchet for combined scanning electron microscopy and X-ray energy dispersive spectrometry (SEM and XEDS). Total mineral particle counts were obtained, and detailed physical characteristics of the fibrous particles were documented at 600, 1,500, 4,500 and 9,000 x in three lungs without, and one lung with, histories of occupational exposure. This preparation method was simple, collected more than 99% of identifiable mineral particles in the chloroform layer, gave excellent object to background contrast without heavy metal coatings, and was suitable for XEDS. Comparable fibrous particles from the chloroform layer could also be studied by selected-area electron diffraction to complement the results of XEDS. By this method, we found particles or fibers larger than 0.1 μm were readily counted and measured at 4,500 x. At 600 x, ferruginous bodies were found to be more than twice in number than when sought for by light microscopy. It was determined that 4,500 x is the most efficient magnification to examine and diagnose this type of specimen. The present study illustrates the importance of determining the most efficient magnification to be utilized in particle counts.
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  • 8
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    Journal of Electron Microscopy Technique 2 (1985), S. 173-174 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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  • 9
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    Journal of Electron Microscopy Technique 2 (1985), S. 193-200 
    ISSN: 0741-0581
    Keywords: Techniques ; Safety ; Electron Microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: This paper is a condensation of precautions, general information, and common-sense tips designed to assist students in electron microscopy. Although not all circumstances are included and many of the recommendations are common sense, this handout has proven invaluable to beginners in two different multiuser electron microscopy facilities. When integrated by discussion and testing into the initial training period, this information will save the neophyte, lab manager, and others working in a multiuser facility untold hours of frustration, of wasted time, effort, and supplies, and of exposure to the myriad environmental hazards inherent in the performance of electron microscopy. The rationale for these suggestions is included, enhancing problem-solving in situations not covered directly in this presentation.
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  • 10
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    Journal of Electron Microscopy Technique 4 (1986), S. 69-71 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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  • 11
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    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 4 (1986) 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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  • 12
    Electronic Resource
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    Journal of Electron Microscopy Technique 2 (1985), S. 285-292 
    ISSN: 0741-0581
    Keywords: Electron microscopy ; Edge-projection TEM ; Field-emission ; Rho protein ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A new technique for placing biological molecules on metal, insulator, and semiconductor surfaces is described. The procedure requires only 10 μl of solution containing molecules at a concentration of 0.1 - 10 μg/ml. The use of a buffer that does not affect metal substrates, the possibility of fixing the molecules in solution prior to deposition, and the ability to minimize surface tension forces during air drying are other features of the new protocol. Simultaneous deposition on TEM grids and highly curved substrates permits biomolecular adsorption on technologically interesting materials to be visualized in the transmission electron microscope.
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  • 13
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    Journal of Electron Microscopy Technique 2 (1985), S. 293-303 
    ISSN: 0741-0581
    Keywords: PAP ; Nonspecific staining ; Endocervix ; Mucous cells ; Man ; Rabbit ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The presence of nonspecific staining artifacts is a potential problem in ultrastructural immunocytochemistry. In the course of staining for lysozyme in the human and rabbit endocervix, the peroxidase-antiperoxidase complex (PAP) was found to bind to mucous granules in a selective and nonspecific manner. Sections etched in 10% aqueous H2O2, incubated for 5 minutes in 1:50 PAP in Tris-buffered saline (TBS) and subsequently treated with 3, 3′-diaminobenzidine-H2O2, revealed a staining precipitate within the matrix of mucous granules. The same selective and nonspecific staining could also be visualized when horseradish peroxidase (1 mg/ml) was substituted for PAP in the immunocytochemical sequence. Thus, this staining method made the reliable demonstration of the desired antigen difficult. The affinity of PAP for mucous granules can be completely eliminated by subjecting sections, previously etched in H2O2 to expose the antigenic sites, to a 3-minute incubation in immunoglobulin (1:10 human IgA, 1:5 human IgG, or 1:5 antihuman IgG) immediately prior to using PAP in the standard immunocytochemical staining sequence. The use of this modification to Sternberger's unlabeled antibody-enzyme method is recommended because it allows for the elimination of all nonspecific staining artifacts without interfering with specific localization by the primary antibody. The mechanism that causes nonspecific binding of peroxidase to mucous granule constituents is unclear, although carbohydrate binding may play a role in the interaction between mucous granules and peroxidase.
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  • 14
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    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985), S. 371-387 
    ISSN: 0741-0581
    Keywords: Image processing ; Histograms ; Phase contrast ; High resolution ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A real-time method for optimizing the defocus of a conventional transmission electron microscope in the phase contrast imaging mode has been investigated using image histogram data. This method can also be used to minimize the objective lens astigmatism. It will be shown both theoretically and empirically, using a digital television frame store, that a histogram will give the largest peak when an image has a broad and flat contrast transfer function. This method has distinct advantages of speed and minimal computational requirements over obtaining the power spectrum of an image.
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  • 15
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    Journal of Electron Microscopy Technique 4 (1986), S. 343-346 
    ISSN: 0741-0581
    Keywords: TEM ; CBED ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A new method was developed for convergent beam electron diffraction (CBED) and large angle convergent beam electron diffraction (LACBED) in the JEM-100CXII. This method is obtained in the imaging mode using the defocus objective lens and by re-setting condenser-2. A multi-dark field CBED pattern was achieved in two ways.
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  • 16
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    Journal of Electron Microscopy Technique 4 (1986), S. 371-379 
    ISSN: 0741-0581
    Keywords: Scanning electron microscopy ; Low temperature ; Microanalysis ; Duodenum ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Low temperature scanning electron microscopy of mammalian tissue allows microanalysis data and morphological results to be considered together, without the risk of elemental diffusion introduced by liquid fixatives and processing agents. The technique, however, is time consuming and there are many areas where errors are possible and standardization of technique is advisable. The present paper describes some of the problems inherent in handling frozen tissue and comparison is made between microanalytical measurements from luminal contents and those from villous epithelium.
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  • 17
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    Journal of Electron Microscopy Technique 4 (1986), S. 385-397 
    ISSN: 0741-0581
    Keywords: Freeze-fracture ; Ferritin ; Cytoplasmic matrix ; glutaraldehyde ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: We have developed a method - “fracture-permeation” - to assess the compactness of the cytoplasm in glutaraldehyde-fixed cells. Cells or tissues are fixed in glutaraldehyde, impregnated with glycerol, and frozen in liquid nitrogen. The cells are freeze-fractured, thawed, deglycerinated, and immersed in concentrated solutions of globular proteins. In initial experiments, we used native ferritin (NF) to permeate model matrices made of bovine serum albumin (BSA). We show that permeation depends on the concentraion of proteins within the cross-linked matrix: NF permeates matrices made from 10 or 15% (w/v) BSA solutions but do not permeate matrices made from solutions with 20% (w/v) protein or more. With freeze-fractured cells, ferritin molecules were unable to permeate the cross-linked cytoplasm of fungal zoospores and cysts, used here as examples of resting cells. In human lymphocytes from peripheral blood, permeation of ferritin was limited or absent, but it became massive in cells activated by phytohemagglutinin. Massive permeation of ferritin was also observed within the cytoplasmic matrix of other active cells (fungal sporangia, germinating cysts). In the examined resting cells, glutaraldehyde crosslinks the proteins into a dense matrix that effectively excludes ferritin (diameter 12 nm). These findings cannot be explained by models that envisage all cytoplasmic proteins congregated into a single-phase microtrabecular lattice with the nature and dimensions proposed by Porter and co-workers. We conclude that compactness of the cytoplasm matrix depends on the physiological state of the cell: It varies through differentiation and is related to the degree of cellular activity.
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  • 18
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    Journal of Electron Microscopy Technique 5 (1987), S. 51-58 
    ISSN: 0741-0581
    Keywords: STEM image ; SE yield ; Digital image processing ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: An inexpensive, efficient device that supplies a transmission mode to the conventional SEM has been developed. The transmitted electrons strike a metal plate, and these generate secondary electrons that are proportional to the quantity of the transmitted electrons. The generated electrons are collected by the secondary electron detector. Hence, the performance of this device is influenced by the number of secondary electrons generated in the metal plate. In order to construct a device that can attain the best transmitted electron image, the signal-to-noise ratio of images, obtained from various trial devices, were measured by a newly-developed digital image processing program. When the material and shape of the device are selected, to produce high-secondary emission, the efficiency of the device compares with that of a relatively expensive standard detector system (scintillator detector).
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  • 19
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    Journal of Electron Microscopy Technique 5 (1987), S. 105-106 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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  • 20
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    Journal of Electron Microscopy Technique 5 (1987), S. 109-110 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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  • 21
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    Journal of Electron Microscopy Technique 5 (1987) 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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  • 22
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    Journal of Electron Microscopy Technique 5 (1987), S. 159-169 
    ISSN: 0741-0581
    Keywords: Monolayer cells ; Microcarrier beads ; Transmission electron microscopy ; Scanning electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Cross-linked dextran beads provide an excellent surface for tissue-cultured cell monolayers, and can be processed for transmission (TEM) and scanning (SEM) electron microscopy, as well as light microscopy (LM). Cells are grown to confluency on the surface of the microcarriers, where at any point aliquots can be removed and experimentally treated as desired (e.g. immunocytochemistry) providing a representative sample. Sample preparation for TEM follows standard procedures for any cell monolayer, but infiltration times must be at least doubled to allow penetration of the beads. The polymerized blocks can then be sectioned for TEM or LM with no additional steps required. SEM sample preparation involves attaching the fixed bead/cell suspension to a glass coverslip with poly-1-lysine, dehydration, critical point drying, and coating for conductivity. The fixed and dried sample can also be attached directly to the SEM stub as free beads and subsequently gold coated. These beads provide (1) an increased surface area of cells visible per area of thin section, (2) eliminates the careful orientation required for flat substrate methods of embedding, (3) decreases the amount of sample manipulation in the forms of re-embedding and gluing, and (4) decreases the amount of drying artifact seen as cracking in SEM monolayer preparations.
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  • 23
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    Journal of Electron Microscopy Technique 5 (1987), S. 211-215 
    ISSN: 0741-0581
    Keywords: Photography ; Developer ; CBED ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The use of a surface developer, pyrocatechol, to process transmission electron microscope negatives has been shown to have significant advantages over the conventional D-19 process. The process described here is tolerant of a large margin of error in the electron exposure and produces a negative that not only retains details both in the highlight as well as the faint regions, but also preserves local contrast. These characteristics are particularly useful in convergent beam electron diffraction applications where one encounters a wide contrast range. Improved acuteness and an enhanced signal to noise ratio due to the prolonged exposures associated with this process have also been observed.
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  • 24
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    Journal of Electron Microscopy Technique 5 (1987) 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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  • 25
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    Journal of Electron Microscopy Technique 5 (1987), S. i 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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  • 26
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    Journal of Electron Microscopy Technique 5 (1987), S. 303-314 
    ISSN: 0741-0581
    Keywords: Immunocytochemistry ; Retina ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: We have developed a protocol for post-embedding immunoelectron microscopy that utilizes uranyl acetate, en bloc, as a secondary tissue fixative. Squirrel and cat retinas were fixed in 1% paraformaldehyde-1% glutaraldehyde for one hour. Secondary fixation was by 2% uranyl acetate, en bloc, (1 hour) during tissue dehydration. The tissue was embedded in LR White or Lowicryl K4M resin. Post-embedding immunoelectron microscopy (indirect immunogold) was performed on thin sections with antibodies to four different classes of proteins (filamentous, cytoplasmic, membrane, and extracellular matrix). The sections were then stained sequentially on drops of uranyl acetate and lead citrate, and by vapors of osmium tetroxide. Uranyl acetate fixation and/or staining of the sections by osmium tetroxide was omitted from the control experiments. Differences after secondary fixation with uranyl acetate and staining of the thin sections with osmium tetroxide were better overall preservation and enhanced contrast of the extracellular matrix, membranes, cytoplasm, and DNA. Antigenicity, as evidenced by the immunolabeling of the four proteins, was retained. Quantitation of the immunolabeling for the cytoplasmic and membrane proteins revealed significantly increased labeling densities in tissue postfixed with uranyl acetate. The improved tissue preservation and immunolabeling of proteins indicate that secondary fixation with uranyl acetate can be a valuable addition to post-embedding immunocytochemistry.
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  • 27
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    Journal of Electron Microscopy Technique 1 (1984), S. 83-94 
    ISSN: 0741-0581
    Keywords: Scanning transmission electron microscopy ; Image contrast ; Inelastic scattering ; Thick specimens ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: For scanning transmission electron microscopy (STEM) images obtained with relatively small objective aperture sizes, the contrast of small objects contained within thick specimens may be considerably enhanced by using an off-axis detector aperture situated on the edge of the central beam spot. The effect is demonstrated for both crystalline and amorphous specimens. The effect arises because the detector collects part of the small angle inelastic scattering and is modified by refraction effects for specimens of rapidly changing thickness.
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  • 28
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    Journal of Electron Microscopy Technique 1 (1984), S. 107-130 
    ISSN: 0741-0581
    Keywords: Phase contrast ; Computer simulation ; Partial coherence ; Electron microscopy ; Convergent beam ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A general method for computing high-resolution conventional transmission electron microscope images and diffraction patterns, when there are different types of partially coherent illumination conditions, is described. Examples of convergent beam, hollow cone, and virtual aperture illumination conditions are given in the context of interpreting image features. A comparison of real and computed diffraction patterns shows that, in practice, many innovative imaging modes are possible, which can be verified prior to real microscope experiments.
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  • 29
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    Journal of Electron Microscopy Technique 6 (1987), S. 63-79 
    ISSN: 0741-0581
    Keywords: Plastic flow ; Section surface relief ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The technology of ultramicrotomy is now well established, but the properties of the resin that determine the different forces needed to generate a section have been neglected, although this process could introduce artefacts in the thin sections. We have investigated the principal resin dependent factors involved in the sectioning process and determined the related mechanical properties. Tensile experiments have given the best correlation with the sectioning quality of the resin: the elastic (Young's) modulus value (depending on polymer structure or hardening mode), the presence of a short plastic flow for a controlled fracture and enough flexibility to minimize shearing, and internal cracks, appear to be the main characteristic parameters. The ultrathin section seems to be generated by a process close to cleavage, favoured by the relative hardness of the embedding media, while machining and “true” sectioning requires softer resins.Consequently, the rupture follows the path of least resistance in the specimen-resin composite, providing sections with a surface relief. Embedded biological material copolymerizes with polycondensed matrix (epoxy resins), and, by reducing the heterogeneity, gives smoother sections. Embedments hardened by radical polymerization provide a rougher relief, since almost no copolymerization occurs, offering to the microtome a heterogeneous block with two constituents of very different mechanical properties. The surface relief seems to be an important factor in labelling, staining, and imaging, and more attention has to be paid for some improvements of the quality of the information provided by electron microscopy.
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  • 30
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    Journal of Electron Microscopy Technique 1 (1984), S. 175-184 
    ISSN: 0741-0581
    Keywords: Synchronous digital image acquisition and scan generation (SDIASG) ; X-ray imaging ; Scanning transmission electron microscope ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: An intelligent interface has been designed to perform synchronous digital image acquistion and scan generation (SDIASG interface) for a microprocessor controlled Scanning Transmission Electron Microscope (S(T)EM) with x-ray imaging. The SDIASG interface connects an LSI-11/2 microprocessor to a Philips EM400 electron microscope. The LSI-11/2 microprocessor is part of a DeAnza VC5000 digital image display system. A system using the SDIASG interface is described. The system takes advantage of the SDIASG interface and a DeAnza VC5000 digital image display system to realize new capabilities that optimize conditions for x-ray mapping.A low characteristic x-ray count rate is generated by the ultrathin specimens from which high resolution x-ray maps can be obtained (Shuman et al, 1976; Somlyo and Shuman, 1982). This low count rate necessitates a long image accumulation time, which in turn makes drift correction essential for maintaining spatial resolution. The new capabilities of the system described here consist of real-time display and summation of consecutive image and x-ray maps, and automatic return to a high speed imaging mode between consecutive x-ray map passes. The new capabilities combine to allow frequent correction for specimen drift between consecutive x-ray mapping passes while still permitting a long total accumulation time for the x-ray maps.
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  • 31
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    Journal of Electron Microscopy Technique 6 (1987), S. 167-173 
    ISSN: 0741-0581
    Keywords: Microtubules ; Actin filaments ; Aster motility ; Micro-filamentous and microtubular networks ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: This paper summarizes observations on the motility and behavior of microtubule asters in polymorphonuclear leukocytes under a variety of experimental conditions. These observations suggest that the location and organization of microtubules is influenced, at least in part, by the activity of the cortical actin network. Aster motility may therefore serve as an indicator of the interaction between the centrosomal microtubules and the cell cortex, and it is speculated that this interaction is of importance for leukocyte translocation.
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  • 32
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    Journal of Electron Microscopy Technique 6 (1987), S. 175-183 
    ISSN: 0741-0581
    Keywords: HVEM ; Synaptic transmission ; Synapses ; Neurons ; Immunocytochemistry ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: There is a need for an electron microscopic method for visualization of selectively stained neurons and neuronal processes with higher resolution than can be obtained with the light microscope, but using thick sections that allow visualization of the three-dimensional structure of the neuron. Such a method is required for measurement of the geometry of neurons, and this information is needed to test theoretical predictions on the way in which electrical signals of synaptic origin are processed by the cells. The high voltage electron microscope (HVEM) is well suited to this application, because of its high resolution and ability to form images of thick sections. Use of this instrument requires development of selective stains that can produce diffuse cytoplasmic staining of specific cells or cell populations on the basis of their functional properties. Several such methods currently being employed for light microscopic work can be used directly in the high voltage electron microscope or can be made useful by relatively minor alterations. These include intracellular staining with horseradish peroxidase, axonal tracing with Phaseolus vulgaris leukoagglutinin (PHA-L), and immunocytochemical staining for specific cell markers known to stain the cytoplasm of certain cell populations.Cells stained intracellularly by microinjection of horseradish peroxidase during physiological recording experiments may be stained in thick (ca. 50 μm) sections cut on a vibratome or similar instrument and stained in the standard way, using methods designed for light microscopy. The sections are then postfixed in osmium tetroxide and embedded in epoxy plastic. Sections cut from these blocks at thicknesses of from 1 to 5 μm using a dry glass knife may be examined directly in the HVEM with no further staining. This produces a very clear image of the cell on a relatively unstained background. This method provides more than adequate resolution of the boundary of the neuron, allowing measurement of neuronal processes to better than 10-nm precision.Similar results are obtained when the same method is applied to axonal tracing using PHA-L. In this case, the exogenously applied marker is used to label a small population of nearby neurons and to trace their connections with other cells at a distance. The lectin is detected by immunocytochemistry, but the selective contrast of the image is adjustable because the concentration of antigen in the cell is largely controlled by the experimenter. The lectin is distributed diffusely in the cytoplasm in a pattern identical to that of intracellular staining, so like intracellular staining, it reveals the overall shape of the cell.Immunocytochemical labelling using endogenous antigens known to be distributed in the cytoplasm of specific neurons produced inadequate control of selective contrast when prepared in this manner. Instead, 1-10μm sections cut from blocks of nervous tissue were embedded in polyethylene glycol, stained using a combedded in polyethylene glycol, stained using a combination of immunocytochemistry and histochemical intensification methods, and embedded in plastic on the grid. This method, which is also suited for staining with poorly penetrating markers such as colloidal gold, may also prove useful in a variety of other situations requiring the intensification of selective contrast.
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  • 33
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    Journal of Electron Microscopy Technique 6 (1987) 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 34
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    Journal of Electron Microscopy Technique 6 (1987), S. 305-306 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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  • 35
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    Journal of Electron Microscopy Technique 6 (1987), S. 309-310 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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  • 36
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    Journal of Electron Microscopy Technique 1 (1984), S. 331-340 
    ISSN: 0741-0581
    Keywords: Digital image processing ; Laplacin filter ; Scanning electron microscopy ; High-resolution ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Certain digital image-processing methods, which are useful for nonperiodic structural images, have been applied to high-resolution SEM images for the improvement of resolution. Samples utilized in the present study consisted of magnetic tape coated with gold, T4 phage coated with gold-palladium, and uncoated specimens of Prolamellar body (PLB) in Cucurbita moschata. These images were blurred and otherwise disturbed by electronic noise, though the images were taken at the limit of efficiency of intrinsic instrument. The major image-processing tool was the Laplacian filter, which subtracts the Laplacian from the original image. Noise, which is a serious problem in digital processing of high-resolution SEM images, was suppressed by the nonlinear type smoothing method. Also, the noise was evaluated by an autocorrelation function and a power spectrum of the image. By using these methods of “deblurring” and noise removal, we achieved better resolution, and structural details of our biological specimens were revealed.
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  • 37
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    Journal of Electron Microscopy Technique 6 (1987), S. 357-366 
    ISSN: 0741-0581
    Keywords: Electron microscopy ; Immunolabeling ; Skeletal muscle ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Immunoelectron microscopy techniques were used to localize alpha-actinin within the Z lattice of adult skeletal muscles. Analysis of electron micrographs by direct visualization demonstrated that anti-alpha-actinin Fab fragments bound throughout the Z lattice. A low-resolution scanning densitometry technique was developed to quantitate the visual increase in the density of the Z lattice. These techniques did not allow determination of the particular component of the Z lattice, amorphous matrix, axial filaments, or cross-connecting filaments with which the antibody was associated. Therefore, additional techniques, including direct measurement of filament diameters and optical diffraction, were utilized in determining which components of the Z lattice bound anti-alpha-actinin Fab fragments. These analyses suggest that the antibody binding is distributed evenly throughout the lattice, along the filaments, and between them and is confined to the region of double overlap of the ends of the thin filaments.
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  • 38
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    Journal of Electron Microscopy Technique 7 (1987), S. 29-33 
    ISSN: 0741-0581
    Keywords: Specimen preparation ; Negative staining ; Freeze-drying/metal-shadowing ; Biological electron microscopy ; Specimen adsorption ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: We describe the design, construction, and operation of a simple glow discharge unit that can be used to make surfaces such as carbon-coated electron microscopy grids and glass coverslips hydrophilic. The use of a vacuum leak detector (Tesla coil) in place of a conventional high-voltage power supply and a small plastic desiccator for the vacuum chamber make the unit very inexpensive. Owing to the small volume of the chamber and the simplicity of the unit, the whole glow discharge process can be carried out in only 2 to 3 min, a time considerably shorter than that required for conventional vacuum evaporators. The hydrophilic surface improves adsorption of particles by several orders of magnitude in preparation for negative staining, freeze-drying, and other procedures.
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  • 39
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    Journal of Electron Microscopy Technique 7 (1987), S. 53-60 
    ISSN: 0741-0581
    Keywords: Montage ; Collage ; Display ; Photographic technique ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The preparation of overlapping electron micrographs (particularly from transmission electron microscopy) requires special forethought in planning, exceptional skills in microscopy and photographic techniques, as well as in display preparations which are unique in their handling and execution. In this report, step-by-step instructions are given on specimen preparation, micrography, darkroom printing, and mounting for montage display purposes.
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  • 40
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    Journal of Electron Microscopy Technique 7 (1987), S. 85-89 
    ISSN: 0741-0581
    Keywords: Gap junctions ; Amphibia ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: By electron microscopic observations of freeze-etching replicas, the gap junctions of ectoderm cells of early gastrulae of Xenopus leavis, injected with antibodies against gap-junction protein at an earlier stage, were compared with those of normal gastrulae. Most of the gap junctions found in the antibody-injected series were of very small size and consisted of fewer than 40 connexons, while those of the normal gastrulae usually have gap junctions with over 100 connexons. It was concluded that the normal assembly of intramembranous particles to form gap junctions was attenuated by microinjection of the antibodies.
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  • 41
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    Keywords: Goat poxvirus ; Bovine rhinotracheitis virus ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: We studied the morphology and morphogenesis of viral envelopes and nucleocapsids of goat poxvirus (GPV) and infectious bovine rhinotracheitis virus (IBRV) by means of the freeze-fracture technique. The GPV at an early development stage was fractured in its middle, and the envelope was shown to be a bilayer of particles. The mature GPV was fractured between two monolayers of the envelope. These facts suggest that there is little lipid and mainly protein particles in the envelope at the early-development stage, then the lipid inserts into the envelope during viral development. We found that there were still many intramembranous protein particles in protoplasmic fracture face (PF) and extracellular fracture face (EF) of the envelope of mature GPV in the cytoplasm, and fewer particles in the envelope of released GPV. In the envelope of mature IBRV, however, there were many more intramembrane protein particles in the PF face than that in the EF face. Spike-like structures could be seen at the outer edge of the IBRV envelope at times. Protein particles were regularly arranged in the plasmic membranes contacting IBRV. This phenomenon seems to be related to IBRV release. The naked cores, empty capsids, and nucleocapsids of IBRV were assembled in the nucleus of infected cells at the same time. The assembled nucleocapsids could be divided into five types according to their different fracturing positions, whose morphology was observed after deep etching. The morphology of the samples prepared with different methods was compared as well.
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  • 42
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    Journal of Electron Microscopy Technique 7 (1987), S. 131-148 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 43
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    Journal of Electron Microscopy Technique 7 (1987), S. 167-175 
    ISSN: 0741-0581
    Keywords: Morphometry ; Organelle arrangement ; Exocrine glands ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Currently available morphometric methods provide useful information on the three-dimensional properties (such as volume, surface, etc.) of biological structures. These methods, however, do not reveal how the same structures are spatially organized within the cell. A sum of problems, which concern mainly the definition of shape and location of the sectioned structures, does not allow the three-dimensional representation of the organelle arrangement from a quantitative analysis of sections. Following a different approach, this study considers the topographic relationship between ten distinct subcellular structures: nucleus, Golgi, ribosomes, mitochondria, lysosomes, lipid droplets, secretory granules, and apical, lateral, and basal plasmalemma. The analysis of associations from 2 × 2 tables calculated for each pair of structures and the pattern of multiple associations obtained by clustering methods provide a useful description of the spatial relationship among different cell compartments. The results of the investigation carried out in parallel on seven human exocrine glands (pancreas, parotid gland, submandibular gland, lacrimal gland, ceruminous gland, ampulla of the vas deferens, and seminal vesicle) allow an immediate evaluation of the method and a comparative analysis of the cytologic organization of secreting cells of human exocrine glands.
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  • 44
    ISSN: 0741-0581
    Keywords: Autoradiography ; Image processing ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: EMAMAP is a program for the data acquisition phase of maximum-likelihood analysis of electron microscope autoradiographs. This program is written in C and has been implemented on a Masscomp MC-500 which supports a graphics processor and a digitizing tablet. The image analysis is automated at a low level: the program operator outlines the edges of the structures of interest using the digitizing tablet, while contiguous regions formed by closed contours are automatically filled by the software. The resulting image is compressed for efficient storage by a quadtree encoding technique for which data compression ratios of greater than 25:1 have been achieved. In practical terms this implies that the data from a typical experiment of 50 autoradiographs could be stored on a single floppy disk. The system is currently in use for acquiring actual biological experimental data.
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  • 45
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    Journal of Electron Microscopy Technique 7 (1987), S. 223-231 
    ISSN: 0741-0581
    Keywords: Nuclear chromatin ; 20-30 nm fiber loops ; Detergent-lysed cells ; Joy® ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A method for electron microscopic demonstration of supranucleosomal (20-30 nm chromatin) fiber loops was developed. Chicken erythrocytes were treated with varying concentrations of detergents, such as Joy®, sodium N-lauroyl sarcosinate, and sodium laurylsulfate, and then fixed with a formalin solution. The fixed cells were centrifuged onto an electron microscope grid, followed by staining and metal shadowing. Thin-sectioned specimens of the fixed cells were prepared routinely. Although supranucleosomal fiber loops could be observed when any one of these detergents was used, Joy gave the best result. Electron micrographs of rotary-shadowed specimens of erythrocyte ghosts formed by treatment with a low concentration (0.07-0.11 w/w%) of Joy showed a halolike, radial arrangement of supranucleosomal fiber loops around the ghost cells. The width of the halo was about 3μm. By increasing the detergent concentration (∼0.18% Joy), nucleosome fibers and naked DNA appeared and increased in number, indicating that the supranucleosomal fibers were disassembled by the action of the detergent. Thin-sectioned specimens of cells treated with 0.09% Joy showed granulofibrillar chromatin radially dispersed from the nuclear cage. The fibers were thought to be identical with the supranucleosomal fibers observed in the rotary-shadowed specimens.
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  • 46
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    Journal of Electron Microscopy Technique 4 (1986), S. 73-74 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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  • 47
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    Journal of Electron Microscopy Technique 4 (1986), S. 81-87 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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  • 48
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    Journal of Electron Microscopy Technique 4 (1986), S. 113-125 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 49
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    Journal of Electron Microscopy Technique 1 (1984), S. 131-140 
    ISSN: 0741-0581
    Keywords: GACH ; Amino-resin ; SEM ; Preparation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Biological specimens can be prepared for scanning electron microscopy by means of copolymerizing the fixing agent glutaraldehyde with carbohydrazide prior to air drying. Such preparations are more stable in the electron microscope, show less internal cellular disruption and retain more of their native elemental composition than specimens prepared by means of dehydration and critical-point drying. Specimens observed in the scanning electron microscope can often be recovered for thin sectioning with no additional embedment, and can then be observed by means of transmission elecltron microscopy. The preparation (termed GACH) can be performed in almost any laboratory with no specialized equipment and, for the most part, may be carried out at room temperature. The technique appears to provide the promise of further research applications in scanning electron microscopy which may employ conjugated procedures of immunocytochemistry and cathodoluminescence as well as X-ray microanalysis in limited situations.
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    Journal of Electron Microscopy Technique 1 (1984), S. 203-204 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 51
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    Journal of Electron Microscopy Technique 8 (1988), S. 115-131 
    ISSN: 0741-0581
    Keywords: Electron microscopy ; Fungal diagnosis ; Fungal therapy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Defects in cell-mediated immunity caused by infection with the human immunodeficiency virus (HIV) render AIDS patients particularly susceptible to fungal pathogens. Signs and symptoms of serious infection may be nonspecific, and early diagnosis and institution of antifungal therapy is essential to decrease morbidity and mortality in this patient population. In a symptomatic individual, invasive procedures are often required to establish a microbiologic diagnosis, and histopathologic examination of tissue by light and electron microscopy is often the first indication of a serious fungal infection in an AIDS patient.
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  • 52
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    Journal of Electron Microscopy Technique 1 (1984), S. 243-270 
    ISSN: 0741-0581
    Keywords: Immunocytochemistry ; Protein A-Gold ; Lowicryl ; Glycolmethacrylate ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The postembedding protein A-gold immunocytochemical approach has been introduced as an alternative to other techniques for the ultrastructural localization of antigenic sites. The present review deals with the development, the theoretical background, and technical approach of the protein A-gold method as well as the different modifications introduced in order to enhance the resolution of the results and to perform double labelings on the same section. Various examples demonstrate the reliability and the wide range of application of this technique. In addition, some problems, pitfalls, and limitations particular to this method are reported.
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  • 53
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    Journal of Electron Microscopy Technique 1 (1984), S. 271-277 
    ISSN: 0741-0581
    Keywords: Vascular cell cultures ; Transmission electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A method is described for obtaining optimal, reproducible ultrastructure of vascular smooth muscle cells and vascular endothelial cells in culture. Routinely grown cultures are prepared for TEM with a precise regimen of fixation, postfixation, en bloc staining, dehydration, and embedment. The most important aspects of this procedure are the following: (1) fixation with a percentage-gradient series of glutaraldehyde solutions at 37°C, (2) immediate postfixation with osmium tetroxide solution, and (3) block-staining with uranyl acetate solution to eliminate any extraction of constituents during subsequent processing.
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    Journal of Electron Microscopy Technique 1 (1984), S. 289-298 
    ISSN: 0741-0581
    Keywords: Epithelial cell ; Membrane ; Ecto-ATPase ; Stain-replica ; Plasma polymerization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A stain-replica technique is described for cytochemical examination of ecto-adenosine triphosphatase (ATPase) activity over the membrane surface of monolayer cell cultures. Rat liver epithelial cells grown on a plastic substrate were fixed in glutaraldehyde, incubated in situ in an ATPase-lead reaction medium, ethanol-dehydrated and air-dried. The cell surface of the monolayer cultures was replicated with plasma polymerization of hydrocarbon gas in the negative phase of glow discharge. X-ray microprobe analysis confirmed the site-specific deposition of lead phosphate in the polymer-replica films. The cytochemical localization of lead was mirrored in the replicas of epithelial cells, demonstrating that ATPase activity was expressed along the apical margins of cell-to-cell contacts. Little or no activity was present over the remainder of the smooth-surface membranes. In transformed epithelial cells, there were abundant reaction products over the microvilli and intercellular boundaries. These observations were consistent with biochemical data on the liver epithelial cells in culture and suggested the potential of surface-replica cytochemistry.
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    Journal of Electron Microscopy Technique 8 (1988), S. 193-200 
    ISSN: 0741-0581
    Keywords: Thickness measurement ; Electron energy-loss spectroscopy (EELS) ; Inelastic mean free path ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: We discuss measurement of the local thickness t of a transmission microscope specimen from the log-ratio formula t = λ In (It/I0) where It and I0 are the total and zero-loss areas under the electron-energy loss spectrum. We have measured the total inelastic mean free path λ in 11 materials of varying atomic number Z and have parameterized the results in the form λ = 106F (E0/Em)/ln (2βE0/Em) where F = (1 + E0/1,022)/(1 + E0/511)2, the incident energy E0 is in keV, the spectrum collection semiangle β is in mrad, and Em = 7.6Z0.36. This formulation should allow absolute thickness to be determined to an accuracy of ±20% in most inorganic specimens.
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  • 56
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    Journal of Electron Microscopy Technique 5 (1987), S. 91-103 
    ISSN: 0741-0581
    Keywords: Scanning electron acoustic microscopy ; Thermal wave microscopy ; Subsurface imaging ; Composites ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Scanning electron acoustic microscopy is a new technique for imaging the thermal and elastic properties of surfaces and detecting subsurface flaws. It can be carried out in a modified scanning electron microscope. The effects of electron beam energy and phase angle on scanning electron acoustic images of the thermal and elastic properties of surfaces were studied with an alumina fiber/aluminum matrix composite for fiber directions both transverse and coaxial to the surface. Images produced with 10- and 30-keV electrons at beam modulation frequencies of 80-1200 kHz appeared to be identical, with the exception of a lower signal-to-noise ratio for the lower electron energy. This observation suggests that the energy input from the beam can be considered to occur at the surface for electron energies below 30 keV and frequencies below 1200 kHz. Images recorded at 0° phase angle mapped regions of different thermal and elastic properties. Images recorded at 90° phase angle highlighted the boundaries between such regions. Scanning electron acoustic microscopy can image features of different thermal and elastic properties at greater depth than traditional imaging with backscattered electrons. The practical application of the technique to the study of surfaces is illustrated by the imaging of grain structure and subsurface particles for an extruder barrel.
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  • 57
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    Journal of Electron Microscopy Technique 1 (1984), S. 373-385 
    ISSN: 0741-0581
    Keywords: TEM ; Parallax equation ; Freeze-etch ; Pt-C replication ; Hydrated spermidine-condensed DNA toruses ; Stereoheight measurements ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Stereoimaging of hydrated single complex macromolecules requires thin freeze-etch platinum-carbon replicas (≤200 Å) and that the transmission electron microscope (TEM) be equipped with a tilt-rotation eucentric goniometer stage. The original parallax equation is an accurate approximation for high-magnification work, micrographs (105 ×) being less than 0.3% in error. In addition, we have derived formulas for high-magnification work to measure heights, lateral distances, and the object tilt angle for an object not lying flat on the film surface. The accuracy of the height measurements is evaluated on spermidine-condensed DNA toruses. By using the maximum error equation derived from the original parallax equation, we discuss methods to improve the height measurement precision (95% fractile) to the 5-10 Å range.
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    Journal of Electron Microscopy Technique 1 (1984), S. 417-418 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Topics: Natural Sciences in General
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    Journal of Electron Microscopy Technique 1 (1984), S. 419-420 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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    Journal of Electron Microscopy Technique 8 (1988), S. 273-284 
    ISSN: 0741-0581
    Keywords: Superconductors ; Electron microscopy ; Perovskites ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: High-resolution transmission electron microscopes operating at 300 and 400 kV were used to investigate the crystallography and microstructure of the perovskitelike YBa2Cu3O7-x. In this paper, we evaluate the performance attainable with these microscopes both empirically and by computer modelling. Based upon the assumption that oxygen may be a key to superconductivity properties, we have also investigated the visibility of the oxygen sites as well as the heavier yttrium and barium ion positions and the lighter Cu atom positions. We propose a scheme for observing different twin orientations in these structures and hence the oxygen atom positions seen in projection for the [100] and [010].Our observations of both thick and thin regions of Y-Ba-Cu-O materials are reported as well as the problems of adjusting microscope parameters and specimen alignment to obtain interpretable images. We also give a preliminary report on the effects of heat treatment as seen in high-resolution micrographs to assess disorder of the heavy atoms and oxygen vacancies.
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  • 61
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    Journal of Electron Microscopy Technique 5 (1987), S. 171-179 
    ISSN: 0741-0581
    Keywords: Dow latex ; Internal standards ; Electron microscope magnification ; calibration ; Latex sphere instability ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: In the early days of electron microscopy polystyrene latex particles were used as magnification standards. But in contrast to optical diffraction grating replicas made with carbon or SiO with precise line spacings resistant to electron irradiation, the latex spheres undergo changes, and conflicting reports have created some confusion. We used a highly stabilized electron microscope with controlled unchanging objective current in contamination-free conditions to expose standard Dow latex spheres of 0.399 μm (±0,0060 μm) under defined electron beam conditions. We measured the direct intensity of the electron current impinging on the screen. Removing the object from the beam, it is possible to measure the quantity of electrons absorbed by the latex spheres, expressed in nA/μ2. We used two standard intensities: a low intensity with widespread beam, equivalent to a 2-sec exposure time on Kodak electron image plates, and a higher intensity, obtained by increasing Condenser II current (two coarse plots towards crossover) that gives rise to a brightly illuminated observation screen. This is equivalent to a 1-sec exposure time on the same type of plates. It could be shown that all polystyrene particles uniformly decrease in size. This loss of material manifests itself immediately after the start of irradiation. The decrease follows a hyperbolic curve and reaches values of 14.35% size decrease for low radiation intensity after 15 min. An even greater decrease (namely 16.08% size decrease) was found for medium intensity electron bombardment. Sandwiching the particles with thin carbon film has no protective effect. Particle size has been determined on the photographic plates by measuring the shadow cast by 30° angle platinum shadowing and the shrinking particle itself. Particles “shadowed” with an angle 90° permit us to measure the annular concentric “shadow” once the spheres initiate shrinking.
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    Journal of Electron Microscopy Technique 5 (1987), S. 203-209 
    ISSN: 0741-0581
    Keywords: Transmission electron micrograph ; Contrast enhancement ; Bas-relief ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Two methods for bas-relief electron micrographs are described, one to produce transparencies for projection and one to produce prints for publication. The basis of these methods is a controlled misregistration of a positive image and a negative image, both on film, to increase contrast and produce a “bas-relief” effect. This gives the final image a three-dimensional appearance. No apparent loss of resolution results and no artificial amendment is required. To produce transparencies, a contact film positive is produced from the negative and the two are sandwiched in a slide mount with the appropriate amount of lateral displacement to give the effect. To produce prints, the film positive and the film negative are used to sequentially expose the same sheet of photographic paper prior to development to realize the effect. The bas-relief induced by the misregistration of the film plates causes apparent shadows and highlights that produce the apparent height that is seen in the enhanced images.
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    Journal of Electron Microscopy Technique 5 (1987), S. 221-221 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 64
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    Journal of Electron Microscopy Technique 5 (1987), S. 249-261 
    ISSN: 0741-0581
    Keywords: Specimen preparation ; Three-dimensional image ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The application of the conventional double-fixation method (glutaraldehyde and osmium tetroxide) to whole yeast cells is difficult because the thick cell wall of the yeast prevents the penetration of osmium tetroxide. However, this problem was solved by using the freeze-substitution fixation method. Therefore, it was possible to examine the intracellular structures of the yeast cells without digestion of the cell wall. In the present method, specimens for transmission electron microscopy and for scanning electron microscopy were prepared simultaneously. By scanning electron microscopic observation, three-dimensional information about internal structures was obtained. In the cytological analysis of the yeasts, intracellular structures were well preserved by using the freeze-substitution fixation method. On the outer leaflet of the nuclear envelope, many ribosomes were attached. The rough endoplasmic reticulum and Golgi apparatus were clearly seen in the yeast cytoplasm. The Golgi stack appeared to consist of smooth membranes, and small vesicles were present beside it. The details of other structures such as the nuclear division apparatus, actinlike filaments, and viruslike particles were also revealed. The present technique can be applied to most species of yeast cells. With this new information, the previous model of a yeast cell was modified.
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    Journal of Electron Microscopy Technique 2 (1985), S. 171-172 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Journal of Electron Microscopy Technique 2 (1985), S. 175-186 
    ISSN: 0741-0581
    Keywords: Paraphenylene-diamine ; PPD method ; human neuroanatomy ; axonal degeneration ; fiber tracing ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The neuroanatomy of experimental animals has been investigated through a variety of histological and physiological techniques. Recently, more sophisticated methods have permitted a better understanding of the complex connections of animal brains. In contrast, the methods available for the direct examination of the human brain have remained relatively primitive.We have developed a staining method (paraphenylene-diamine method: PPD) which bridges the techniques of light and electron microscopy. The method permits the tracing of degenerated fibers in the human brain even after very long survival periods. With this method we have documented several visual pathways not previously described in man. We have also demonstrated, in several species, that products of axonal degeneration remain far longer than previously supposed. The PPD technique is relatively simple, reliable, provides high resolution, works in human brains, and can be used in conjunction with TEM.
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    Journal of Electron Microscopy Technique 2 (1985), S. 217-228 
    ISSN: 0741-0581
    Keywords: Fish ; electron microscopy ; perfusion methods ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Many of the techniques applied to study the morphology of lower vertebrates were originally developed for analysis of mammalian tissues. However, not all of these methods, especially those involving tissue perfusion, can be directly applied to piscine tissues because of the considerable physiological differences between fish and mammals. The present paper examines these physiological variables in fish and describes how they might affect morphological studies that employ tissue perfusion. A method for perfusion of fish tissues is described in detail. This procedure can be used for administration of fixatives, chemical markers, and vascular replicating resins.
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    Journal of Electron Microscopy Technique 2 (1985), S. 261-262 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 69
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    Journal of Electron Microscopy Technique 9 (1988), S. 283-291 
    ISSN: 0741-0581
    Keywords: Ultrastructure ; Kidney ; Artifacts ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The aim of this presentation is to draw attention to the problems inherent in evaluating the ultrastructure of percutaneous renal biopsies and to discuss some of the special techniques which are useful in this area. It is important to realize that the ultrastructure as it appears in this kind of material does not necessarily reflect conditions in vivo. Comparison with suitable reference material may, however, permit reliable conclusions in terms of pathological diagnosis and pathogenesis. It is advocated that purely qualitative methods, which until now have predominated in ultrastructure work with renal biopsies, be replaced by morphometry and semiquantitative methods when it is possible and practical to do so in any research situation.
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    Journal of Electron Microscopy Technique 6 (1987), S. 1-6 
    ISSN: 0741-0581
    Keywords: Residual ; Asbestos fibers ; Ferruginous bodies ; Amosite worker ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A recurring question that concerns researchers who use digestion techniques for the electron microscopic study of asbestos and ferruginous body (FB) load in tissue is: “Do appreciable numbers of the total fibers or FBs remain adhered to the walls of preparative vials after digestion?”A test series was devised to evaluate the fiber and FB content remaining in digestion vials (glass or plastic) as well as the effectiveness of removing these particulates through variations in the rinsing procedure. The material used for all studies was digested lung tissue from a former amosite asbestos worker. The digestion procedure was based on the bleach technique of Smith and Naylor (Am. J. Clin. Pathol.: 58:250-54, 1972), as modified by Williams et al. (J. Toxicol. Environ. Health:10:627-628, 1982). Aliquots (1.5 ml) of the digests were used to create reproducible standards. These were placed in either the clean glass or polystyrene vials that had been cut to fit in an AMRAY 1000A scanning microscope interfaced with an X-ray energy dispersive analysis system. The aliquots were allowed to remain in the vials for 10 min or 24 h before rinsing was initiated. Aliquots used for the glass vials contained 5.1 × 106 fibers and 20 × 103 FBs, while aliquots for the polystyrene vials contained 6.9 × 106 fibers and 64 × 103 FBs.The maximum errors encountered for the glass and polystyrene vials were, respectively, 0.094% and 0.12% for fibers and 0.0098% and 0.0084% for FBs and are considered small when compared with potential sources for errors in the other stages of the preparative techniques. Also, it was concluded that if at least three thorough rinses are applied, the loss was minimal in either the glass or polystyrene vials.
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    Journal of Electron Microscopy Technique 3 (1986), S. 131-133 
    ISSN: 0741-0581
    Keywords: Lattice fringes ; Planar interfaces ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A simple theory is presented to explain the origin of two-beam lattice fringes and to show how they can be used to derive the displacement vector of planar interfaces. The theory may have some value for pedagogical purposes since it provides some insight and emphasizes the similarity with optical interference experiments.
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    Journal of Electron Microscopy Technique 2 (1985), S. 391-392 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Journal of Electron Microscopy Technique 2 (1985), S. 397-398 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Journal of Electron Microscopy Technique 2 (1985), S. 399-400 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Topics: Natural Sciences in General
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    Journal of Electron Microscopy Technique 6 (1987), S. 131-141 
    ISSN: 0741-0581
    Keywords: Skeletal muscle ; Myofibrils ; Fish ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: We have studied the structure of the M band in fish skeletal muscle using thin sectioning and deep-etching rotary shadowing. A reconstruction of the M band from these images shows it to be formed by obliquely arranged struts, which join the thick filaments to each other. Thickening of the thick filaments' profiles and nodal points where the struts cross each other are responsible for the fine sublines visible in longitudinal sections of the M band region.
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    Journal of Electron Microscopy Technique 6 (1987), S. 193-205 
    ISSN: 0741-0581
    Keywords: HVEM ; EM ; Three-dimensional reconstruction ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The methodology is described, as developed at the Albany NIH Biotechnological High Voltage Electron Microscope Resource, for the three-dimensional reconstruction of objects in thick sections. The reconstructions are obtained from projection sets which are recorded by high voltage electron microscopy. The different steps of the procedure are illustrated in detail, using the cilium reconstruction as an example.
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    Journal of Electron Microscopy Technique 6 (1987), S. 231-235 
    ISSN: 0741-0581
    Keywords: Immunoelectron microscopy ; Cryoultramicrotomy ; Monoclonal antibodies ; Striated muscle ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A systematic approach to the discovery of new proteins of ultrastructural interest is discussed. It involves the merging of monoclonal antibody technology with immunocytochemical technology, particularly immunoelectron microscopy. In this approach, monoclonal antibodies are raised to a cellular preparation that can be grossly heterogeneous in its protein composition. The hybridoma culture fluids are screened by immunocytochemistry for the ultrastructural localization of their antibodies. Those monoclonal antibodies that show specific ultrastructural localizations of interest are then selected for further investigation. The antigen to which a given monoclonal antibody is directed is then identified by immunoprecipitation and immunoblotting with that antibody. By this approach, two new striated muscle proteins of ultrastructural interest have been discovered and are named zeugmatin and enactin. The former is a protein of over 500 kD localized by immunoelectron microscopy to the Z-bands, the latter of 245 kD localized to the N1 line of striated muscle.
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    Journal of Electron Microscopy Technique 6 (1987), S. 307-308 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Journal of Electron Microscopy Technique 6 (1987), S. 315-316 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Journal of Electron Microscopy Technique 6 (1987), S. 335-348 
    ISSN: 0741-0581
    Keywords: Digestive techniques ; Vascular elastic networks ; SEM ; Blood vessels ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Two digestion procedures are now available to expose and isolate networks of vascular elastic fibers for three-dimensional SEM observation. This study was designed to observe and elucidate the differences between the two types of digestion (sodium hydroxide vs. formic acid) and the differences between the two types of dehydration (ethanol-critical-point drying vs. freeze drying) used in each procedure. Canine venous valve segments, containing delicate networks of elastic fibers, and femoral arteries, containing large elastic lamellae, were used to compare the effects of the digestion and dehydration procedures on two types of vessels with different content and organization of elastic tissue. Results indicated there was no significant difference in the architecture of the elastic networks of either vessel based on the method of digestion. The major architectural changes in the elastic networks occurred as a result of the dehydration procedure used following digestion. Freeze drying is probably the best for arterial specimens due to their prominent lamellae, which give added support to maintain their normal architecture. It is suggested that both methods of dehydration be used on corresponding venous specimens containing delicate elastic networks. In this way, the investigator can benefit from the advantages of each method and overcome their respective disadvantages to get a more accurate picture of the three-dimensional architecture of these delicate networks.
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    Journal of Electron Microscopy Technique 6 (1987), S. 367-376 
    ISSN: 0741-0581
    Keywords: Stacking faults ; Dynamical theory calculations ; Digital image processing ; Weak beam images ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: An analysis of the effects of strain and surface roughness on the contrast of weak beam images of small metallic particles is carried out. in order to study these effects, theoretical calculations of the intensity obtained in wedge-shaped bent gold crystals were performed. These calculations were based on the standard form (Bethe's approach) of the dynamical theory. The theoretical results were compared with weak beam experimental images of gold particles. It was found that the image contrast obtained in thin crystalline regions is not sensitive to strain. Therefore, intensity variations experimentally obtained in these regions seem more likely to be related to the surface roughness of the crystalline specimen. We also studied (experimentally and theoretically) the image-contrast characteristics of stacking faults in small particles. The comparison between the experimental micrographs and the theoretical images suggests a possible model of the small particle shape. This model seems to explain most of the experimentally observed image-contrast characteristics.
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    Journal of Electron Microscopy Technique 7 (1987), S. 1-16 
    ISSN: 0741-0581
    Keywords: External determinants ; Colloidal gold ; High-voltage electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Conventional freeze-fracture techniques were combined with immunogold labeling and with plastic embedding and sectioning to analyze the distribution of membrane immunoglobulins (mIgs) and their associated intramembrane particles (IMPs) in E-face replicas of murine B-lymphocyte plasma membranes. Immunogold labels were applied to cells after the process of freeze-fracture and replication. Conventional stereoscopic transmission electron microscopic examination of sectioned, labeled replicas (SLRs) revealed that the gold-labeled mIgs were bound to and localized on the outer leaflets of split and replicated membranes. The gold labels were attached to the external determinants of the mIg molecules, which were retained beneath and contiguous with the replicated E-faces. The mIgs were also localized on the external surface of unreplicated microvilli. In addition, thick sections examined by high-voltage transmission electron microscopy (HVEM) revealed large expanses of replica with well-resolved IMPs. mIgs colocalized with small-diameter (〈60 Å) IMPs in E-face replicas of B-lymphocytes whose mIgs were patched by anti-immunoglobulin. Thus, postreplication E-surface labeling of split and replicated membranes is a high-resolution technique that is suitable for the study of membrane protein distribution in E-face replicas and contiguous nonreplicated tissue.
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    Journal of Electron Microscopy Technique 3 (1986), S. 369-370 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Topics: Natural Sciences in General
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  • 84
    ISSN: 0741-0581
    Keywords: Bacterial identification ; Light microscopy ; Scanning electron microscopy ; Transmission electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A method for bacterial identification has been developed by means of studying the same histological sections through several types of microscopy. With this method, one section was processed and analyzed respectively for light microscopy (LM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Sections of gingival biopsies were Gram stained and bacteria tentatively identified by LM. Photographs of the sections were taken and presketched transparent acetate sheets (PTAS) were made from the photos. The same section was later prepared for SEM, areas previously thought to contain bacteria were localized by placing the PTAS onto the SEM monitoring screen. The SEM specimens were subsequently processed for TEM, bacteria were located, and micrographs obtained. The results showed that out of ten diseased gingival biopsies observed under the LM, bacteria were found to be present in all the specimens and were identified as both Gram positive and Gram negative. By transferring the section from LM to SEM, the bacteria could be relocated and their morphotype (cocci, rods, etc.) clearly identified in most of the cases. Since cocci may resemble other biological granular structures under SEM, they require further analysis under TEM for additional positive identification. This study demonstrated that the method described here is a useful tool for assessing the presence and identifying bacteria within the gingival tissues.
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  • 85
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    Keywords: Electron microscopy ; Morphometry ; Lymphocytes ; Lymphoma ; Nucleus ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Currently, quantitative studies of malignant lymphoma are being performed in an attempt to improve the classification of non-Hodgkin's lymphoma (NHL) for diagnostic, prognostic, and therapeutic purposes. Morphometric image analysis is one method that can be employed in cases of NHL to obtain objective data of nuclear parameters; condensed chromatin being a compartment of the nucleus best measured at the ultrastructural level. This report assesses similarities or differences in the amount, distribution, and arrangement of condensed chromatin in nuclear profiles of normal and neoplastic lymphocytes in human surgical biopsy specimens. Morphometric data derived from electron micrographs of lymphocytes in germinal centers of lymph nodes with reactive hyperplasia (three cases) and small cell types of NHL two examples of malignant lymphoma, well differentiated lymphocytic type (ML, WDL) and three cases of malignant lymphoma, poorly differentiated lymphocytic type (ML, PDL) are compared. Results indicate that the distribution of condensed chromatin, i.e., the size of aggregates, and their spatial placement within the nucleus varies more than the amount (both mean area per profile or mean volume) of this nuclear parameter, and that this applies to normal as well as neoplastic lymphocytes. When a series of condensed chromatin parameters were statistically compared, no major differences could be detected between lymphocytes in normal tissues and those in ML, WDL and ML, PDL, but considerable differences were found in each of the nuclear morphotypes in the individual cases within the groups. This degree of variation in nuclear characteristics within normal tissues and the two lymphoma categories has not been previously recognized. Clearly, the technique of morphometric analysis, as applied to electron micrographs, can provide new and useful data that must be appreciated if classification schemes currently used in NHL are to improve and reflect biologic considerations.
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    Journal of Electron Microscopy Technique 2 (1985), S. 649-652 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Journal of Electron Microscopy Technique 2 (1985), S. 647-647 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Journal of Electron Microscopy Technique 2 (1985), S. 661-661 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Journal of Electron Microscopy Technique 3 (1986), S. 3-3 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Journal of Electron Microscopy Technique 3 (1986), S. 45-56 
    ISSN: 0741-0581
    Keywords: High voltage electron microscopy ; High resolution electron microscopy ; Amorphous ; Amorphization ; Niti alloy ; Mosaic block ; Electron irradiation damage ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Amorphization induced by electron irradiation in Ni-50 at% Ti crystals has been investigated by electron microscopy. In order to clarify successive stages of amorphization, micrographs were taken in vairous regions where the total dose of electrons was continuously changed. Contrast was manipulated by changing the reflecting condition. Results obtained are summarized as follows: (a) Amorphization occurs inhomogenously; (b) there is a critical size, i.e., about 5 nmø in the crystals, for observing sharp lattice images in small blocks; (c) lattice images change to short and wavy fringe contrasts when the block size becomes smaller than the critical one, and finally they disappear; and (d) boundary contrast of the blocks rapidly decreases with decreasing size, and is hardly observed when the size becomes smaller than the critical one. Based on the results, the cause of abnormal fringe contrasts in fine blocks, the amorphization process, and atomic structures of amorphous materials are discussed.
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  • 91
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    Journal of Electron Microscopy Technique 3 (1986), S. 25-44 
    ISSN: 0741-0581
    Keywords: Electron diffraction ; Scanning transmission electron microscopy ; Microdiffraction ; In-line holography ; Small particles ; Crystal structure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Because of the high brightness of the cold field emission source used in a dedicated scanning transmission electron microscopy (STEM) instrument, it is possible to focus electrons to a cross-over of width 3Å or less and, with a suitable detection system, to obtain diffraction patterns from specimen regions of this size or greater. Coherent interference effects are visible in shadow images (in-line holograms) and in convergent beam diffraction patterns. Special techniques have been developed for gathering information from the diffraction patterns for application to the study of the structures of crystal defects, crystal surfaces and small particles. Possibilities have been explored for holographic reconstruction from shadow images.
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  • 92
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    Journal of Electron Microscopy Technique 3 (1986), S. i 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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  • 93
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    Journal of Electron Microscopy Technique 3 (1986), S. 169-176 
    ISSN: 0741-0581
    Keywords: Shadowing ; Unidirectional ; Rotary ; Computer simulations ; Screening ; Void space ; Resolution ; Interpretation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: This work employs a Fortran program to simulate rotary shadowing, that is, metal evaporation deposits in which the substrate is rotating during the deposition process. The results are compared with computer simulations of unidirectional shadowing published in a previous paper. (See Colquhoun et al., 1985). The analysis shows that a substantial improvement in resolution is possible with rotary shadowing. The improved information retrieval amounts to ∼15% with a shadow angle of 33° and ∼37% with a shadow angle of 8°. Unidirectional shadowing results in a grain linearity; the computer simulations show that this undesirable effect is eliminated by the rotary process.These advantages of rotary shadowing are discussed along with the more straight forward interpretability of the rotary shadowed images. These advantages are weighed against the higher contrast generated by the unidirectional shadowing process.
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  • 94
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    Journal of Electron Microscopy Technique 7 (1987), S. 319-322 
    ISSN: 0741-0581
    Keywords: Cross-sectional transmission electron microscopy (XTEM) ; LSI circuit ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Cross-sectional transmission electron microscopy (XTEM) has been used to diagnose silicon LSI circuits and Josephson junction devices. For LSI circuits, some typical failure problems have been presented. For Nb-Si-Nb Josephson junction, microholes in the thin silicon layer have observed, and they are responsible for the short circuiting of these devices.
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  • 95
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    Journal of Electron Microscopy Technique 8 (1988), S. 1-1 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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  • 96
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    Journal of Electron Microscopy Technique 8 (1988), S. 105-113 
    ISSN: 0741-0581
    Keywords: Electron microscopy ; Histopathology ; Mycobacterium diagnosis ; Mycobacterium therapy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: This reviw examines an important bacterial infection in acquired immunodeficiency syndrome (AIDS). Despite occasional infections with bacteria such as Streptococcus pneumoniae, Haemophilus influenzae, Salmonella, and Nocardia in patients with AIDS, the primary problems of AIDS and invading bacterial infections center around mycobacteropsos. A unique feature of AIDS has been the common identification of disseminated infections with Mycobacterium avium-intracellulare. The following discussion examines our present understading of this group of organisms and how they interact with the compromised host.
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  • 97
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    Journal of Electron Microscopy Technique 4 (1986), S. 265-301 
    ISSN: 0741-0581
    Keywords: Diagnostic virology ; Clinical virology ; Clinical electron microscopy ; EM techniques ; Virus morphology ; Virus identification ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Electron microscopy can aid in the rapid diagnosis of viral diseases, as it can be performed in a matter of hours, but on a routine basis it should be used in conjunction with other techniques. Initially, the specimen source and patient symptoms should be ascertained, as these will lend suggestions of possible agents while eliminating others; however, this information should not be allowed to prejudice observation in such a way as to cause oversight of an unlikely pathogen. Second, selection of the method of preparation should be based on sample consistency; extraction, debris clarification, concentration, tissue culture amplification, or embedment may be necessary. Finally, false-positive results must be avoided by differentiating viruses from cell organelles or debris, mycoplasmal or bacterial contamination, and bacteriophages.
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  • 98
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    Journal of Electron Microscopy Technique 4 (1986) 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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  • 99
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    Journal of Electron Microscopy Technique 4 (1986), S. 347-360 
    ISSN: 0741-0581
    Keywords: Microtubules ; Fungus ; Embedment-free sections ; Freeze substitution ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Hyphae of the fungus Basidiobolus magnus were embedded in extractable polyethylene glycol (PEG) or diethylene glycol distearate (DGD) to prepare embedment-free sections in order to seek components of the cytoskeleton that may be obscured in epoxy-embedded sections. All methods showed that hyphae possess an intricate filamentous matrix, which is apparently unoriented. However, the appearance of the cytoskeleton depended on the embedding medium, the solvent used during embedding, and whether cells were fixed by conventional fixation or freeze-substitution. PEG proved to be the best embedding medium for fungal cells because DGD caused cell shrinkage and produced a more lamellar than filamentous matrix. Also, the cytoskeletal filaments were clearer in freeze-substituted cells than in conventionally-fixed cells. Since we failed to find microtubules in the embedment-free sections, we re-embedded cells in Epon to discern whether microtubules or other cytoplasmic components had changed. Neither PEG nor DGD adequately preserved microtubules as compared to regular Epon-embedded sections, and other cellular structures were significantly altered. Therefore, alternative methods need to be employed to further characterize fungal cytoskeletons.
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  • 100
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    Journal of Electron Microscopy Technique 4 (1986), S. 329-342 
    ISSN: 0741-0581
    Keywords: Fracture-permeation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: We show that “fracture - permeation” - a method developed to assess the compactness of the cytoplasm - can establish the distribution of intermolecular spaces in the sarcomeres of glutaraldehyde-fixed striated muscle. As examples of striated muscle, we use sartorius muscle from toad (Bufo marinus) and papillary cardiac muscle from the left ventricle of Sprague - Dawley rats. Tissues were fixed in glutaraldehyde, frozen, cross-fractured in liquid nitrogen, and thawed. Tissue fragments were immersed in concentrated solutions of native ferritin (30% w/v). Random fractures gave ferritin direct access to all regions of the sarcomere. We show that a sequence of four qualitatively distinct patterns of ferritin distribution is associated to a progressive sequence of sarcomere lengths. The correspondence between sarcomere lengths and patterns of ferritin permeation permits the recognition of sarcomeres in rigor (no penetration of ferritin), stretched (penetration into the I band and H zone), or at rest length (penetration restricted to the I band). Similar patterns of ferritin permeation can also be recognized in oblique sections. In cardiac muscle, ferritin permeates into the A bands of contracted sarcomeres and shows an increase in disorder within the filament lattice during contraction. The patterns of ferritin permeation observed in sarcomeres in rigor, stretched, or at rest length are those predicted from changes in filament overlapping proposed by Huxley's “sliding filament theory of muscle contraction.” Our results illustrate the power of fracture-permeation to investigate intermolecular distances in cytoplasmic matrices.
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