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  • 1
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 27 (1994), S. 278-283 
    ISSN: 1059-910X
    Schlagwort(e): Matrix ; Membrane ; SEM ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: The three-dimensional organization of the internal compartments of conventionally fixed and embedded rat-liver mitochondria has been determined by tomographic reconstruction from tilt-series images collected on the Albany high-voltage electron microscope. The results indicate that the inner membranes of these organelles are predominantly tubular in the orthodox (expanded matrix) conformation, as previously suggested by scanning electron microscopy. In the condensed (contracted matrix) conformation, the intracristal space opens up into large irregularly shaped compartments which are connected to each other and to the external (intermembrane) space by tubes with approximately the same diameter (20 nm) as those observed in the orthodox state. These results raise several questions, in particular about the nature of the structural transitions that occur in the cristae during matrix expansion and contraction, and about the influence of inner-membrane shape on the diffusion of ions and metabolites between the intracristal and intermembrane compartments. © 1994 Wiley-Liss, Inc.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    ISSN: 1059-910X
    Schlagwort(e): Lymphoma ; Splenomegaly ; SEM ; TEM ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Peripheral blood mononuclear cells (PBLs) from 14 patients with low grade non-Hodgkin's B-cell lymphomas with predominant splenomegaly were studied by means of scanning (SEM) and transmission electron microscopy (TEM). All patients had peripheral blood and bone marrow involvement, the absence of lymphoadenopathy, and, except in one case, immunophenotypic features of a malignant proliferation of mature spleen B-cells arising from outside the germinal center, but not consistent with CLL or HCL. Several distinctive cytological features were observed in PBLs of the different subgroups. The SEM surface features of PBLs in patients with intermediate differentiation lymphocytic lymphoma (IDL) (five cases), lymphoplasmacytoid immunocytoma (LP-IC) (two cases), and mixed small and large cells malignant lymphoma (one case) were characterized by the presence of numerous well-developed microvilli. Some distinctive TEM ultrastructural features were also seen in the different cases. In the two cases of splenic lymphoma with villous lymphocytes (SLVL), SEM revealed large and elongated surface microvilli generally arising from two or three poles of the cells. This surface morphology, confirmed by TEM analysis, may be pathognomonic of this disease. Four additional cases, tentatively classified as small lymphocytic lymphoma on the basis of immunophenotypic data, were extremely heterogeneous at both SEM and TEM analysis. The ultrastructural features revealed by SEM and TEM may be useful for the more precise characterization of this heterogenous group of diseases, which is generally difficult to define even when immunophenotypic and molecular approaches are used. © 1994 Wiley-Liss, Inc.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 28 (1994), S. 67-74 
    ISSN: 1059-910X
    Schlagwort(e): Al coating ; Frozen hydrated specimens ; Gels ; Longitudinal sections ; Microanalysis ; Morphometric analysis ; Plant tissues ; SEM ; Serial sections ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: A procedure is described for forming a flat face on a frozen piece of plant tissue, which may then be observed fully-hydrated or lightly etched, and coated or uncoated with a metal film, in scanning electron microscopy (SEM). The frozen sample was planed with a glass knife at -80°C in cryo-ultramicrotome. The sections were discarded, and the planed block face placed on the cold stage in the microscope column, either for observation uncoated at low kV, or for light etching (-90°C) to reveal the cell outlines. If a higher accelerating voltage was needed, the face was given an evaporative coating of Al in the cryo-preparation chamber and returned to the column. The advantages of the planed face over the usual fracture face are illustrated: imaging at a chosen rather than a chance position; clearer cellular and subcellular detail; preservation of hydrated gels like mucilage and swollen cell walls; the possibility of making serial parallel sections through the same piece of tissue; opportunities for accurate morphometric analyses on the planed face; capacity to produce longitudinal sections; preservation of very delicate structures that are destroyed by fixation and drying. A major advantage of the Al-coated planed face is the increased accuracy of energy-dispersive X-ray (EDX) microanalyses on a smooth rather than a rough surface. Tests are included which show that neither the light etching employed, nor successive planing, interferes with the analyses of elements in the frozen face. © 1994 Wiley-Liss, Inc.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 27 (1994), S. 429-438 
    ISSN: 1059-910X
    Schlagwort(e): Biological pattern formation ; Cuticle ; Thin-film ; Lattice ; Scanning electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: All butterfly and moth scales and bristles are made of non-living insect cuticle. Each is the product of a single epithelial cell, and all share the same basic architecture. However, some are highly specialized, and their cuticle is further elaborated into stacks of thin-films, lattices, or other minute structures, many of which first came to our attention because they interact, with light to produce structural colors. The scale cell forms the scale by extruding a projection of itself and secreting around it the outer epicuticle, a thin cuticular envelope which will form the outermost layer of the scale. The inner layers of cuticle, collectively called the procuticle, are secreted thereafter and go on to form the lattices, pillars, or other internal structures of the scale. We believe that the pattern-forming mechanisms used by the cell to shape the cuticle into its finished form include elastic buckling of the outer epicuticle to produce external folds, and “masking” of certain areas of the original epicuticular envelope to produce thin spots which will break through to become windows. Varied though they be, all insect cuticular patterns have common basic elements, which suggests that our findings may be generalized to other highly patterned insect cuticles, particularly those formed by single cells. © 1994 Wiley-Liss, Inc.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 28 (1994), S. 277-285 
    ISSN: 1059-910X
    Schlagwort(e): NK cells ; Neutrophils ; Fcγ receptor ; Immunogold ; SEM ; Backscattered electron imaging ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Human natural killer cells and polymorphonuclear neutrophils constitutively express the low-affinity IgG Fc receptor (FcγRIII, CD16 molecule). To investigate cell surface morphology, antigenic receptor density, and topographical distribution of FcγRIII on the plasma membrane of natural killer cells and polymorphonuclear neutrophils, conventional scanning electron microscopy (SEM), flow cytometry, and immunoscanning electron microscopy were used. FcγRIII was detected with an indirect immunogold labeling procedure, and receptors were visualized in the backscattered and secondary electron imaging mode of SEM. Natural killer cells showed a cell surface morphology compatible with lymphocytic differentiation characterized by microvilli and microridges. Polymorphonuclear neutrophils showed surface features characterized by ridges with folds and scattered short microvilli. Natural killer cells displayed a lower cell labeling density, whereas polymorphonuclear neutrophils showed a high level of expression of FcγRIII on the plasma membrane by quantitative analysis with SEM in the backscattered electron imaging mode. Flow cytometry analysis confirmed these findings. Analysis of the topographical distribution of FcγRIII antigenic receptor sites by SEM in the backscattered and secondary electron imaging modes showed that FcγRIII on natural killer cells are randomly distributed, whereas FcγRIII are located on ridges and folds of the plasma membrane of polymorphonuclear neutrophils. These observations suggest that natural killer cells and polymorphonuclear neutrophils differ in their levels of expression and topographic distribution of FcγRIII on the plasma membrane. This different spatial distribution of FcγRIII would provide morphological evidence of certain cellular functions mediated by natural killer cells and polymorphonuclear neutrophils. © 1994 Wiley-Liss, Inc.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 29 (1994), S. 411-431 
    ISSN: 1059-910X
    Schlagwort(e): Corrosion casts ; LM ; SEM ; TEM ; Microvasculature ; Ultrastructure ; Absorption ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: The aim of the present study was to provide a comprehensive morphological analysis of the porcine epididymis in view of the specific functions being performed in different regions of this organ. Blood supply and microvasculature of efferent ductules and epididymal duct were investigated by means of corrosion casts which were analysed macroscopically and by scanning electron microscopy. This revealed blood supply to the testis and epididymis to be closely related. The capillary pattern was typical for the efferent ductules, the caput, corpus, and distal cauda epididymidis, respectively. Corrosion casts were also used to visualize the course of the efferent ductules themselves. Tissue samples from different regions of the efferent ductules and epididymal duct were examined by light microscopy and both scanning and transmission electron microscopy, with special attention being payed to transitional areas. Morphological criteria allowed the distinction of three segments within the efferent ductules and of the initial segment, proximal caput, distal caput, corpus, proximal cauda, and distal cauda regions of the epididymal duct. Components of the endocytic apparatus of efferent ductule principal cells were identified by ferritin uptake. Ultrastructural evidence of absorption in the epididymal duct was particularly prominent in proximal and distal caput. Extensive cisternae of rough endoplasmic reticulum and a well-developed Golgi apparatus were indicative of active protein synthesis and secretion especially in the distal caput and corpus regions. However, assignment of various organelles in principal cells of the epididymal duct to either absorptive or secretory pathways still remains tentative. © 1994 Wiley-Liss, Inc.
    Zusätzliches Material: 53 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 28 (1994), S. 286-296 
    ISSN: 1059-910X
    Schlagwort(e): RBC ; SEM ; Colloidal gold ; Silver enhancement ; Double labeling ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: The majority of mouse monoclonal antibodies reacting with blood group epitopes on erythrocytes are of the IgM class, have equal light chain type, and are available as culture supernatants only. To study the interrelationship of the blood group antigens, a method is presented which allows double labeling applying two unconjugated monoclonal antibodies of the same class and species. The method comprises two indirect, sequential labelings using mouse IgM anti-A and anti-H as primary antibodies and two goat anti-mouse IgM conjugated to 30 and 20 nm colloidal gold particles as secondary antibodies. After labeling for the first antigen, free binding sites on the primary antibody are blocked by incubation with an unconjugated goat anti-mouse antibody. The free anti-species on the secondary antibody, conjugated to 30 nm gold particles, are inactivated by silver enhancement. The silver enhancement also enlarges the gold particle for optimal discrimination between the two particle sizes, which are chosen accordingly. Semiquantitations of double labeled cells from subgroup A2 and A3 were found to be in good agreement with the counts of the corresponding single labelings as well as between experiments, irrespective of which of the two antibodies was applied in the first labeling sequence. The results were in accordance with a reciprocal but nonlinear relationship between the A and H antigens and suggest different affinities of the two antibodies for the epitopes in the subgroups investigated, indicating different biochemistry of the antigen determinants. © 1994 Wiley-Liss, Inc.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 27 (1994), S. 25-45 
    ISSN: 1059-910X
    Schlagwort(e): Transmission electron microscopy ; Scanning electron microscopy ; Histochemistry ; Cytokeratins ; Microfilaments ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: In salivary glands and other exocrine organs, there are starfish-shaped cells that lie between the basal lamina and the acinar and ductal cells. These have structural features of both epithelium and smooth muscle cells, and so are called myoepithelial cells. Their functions include contraction when the gland is stimulated to secrete, compressing or reinforcing the underlying parenchymal cells, thus aiding in the expulsion of saliva and preventing damage to the other cells. They also may aid in the propagation of secretory and other stimuli. Their common developmental origin with the basal cells of the larger ducts is displayed in the mature glands by shared structural and immunohistochemical features, but most such basal cells do not have the distinguishing features of myoepithelial cells, such as myofibrils. Although myoepithelial cells can be identified by light microscopy through enzyme histochemistry and special stains and immunohistochemistry for their myofibrils, these techniques can be misleading in salivary gland neoplasms. Thus, the most reliable means of identifying neoplastic myoepithelial cells is with a combination of histochemistry and electron microscopy. The extent to which these cells are derived from undifferentiated stem cells in both normal and neoplastic growth is controversial. The presentation here of transmission electron microscopy (TEM) of well-differentiated myoepithelial cells in mitotic division indicates that stem cells are not necessarily the only source of myoepithelial cells in the later stages of salivary gland development or in neoplasia. © 1994 Wiley-Liss, Inc.This article is a US Government work and, as such, is in the public domain in the United States of America.
    Zusätzliches Material: 19 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 28 (1994), S. 430-439 
    ISSN: 1059-910X
    Schlagwort(e): B Lymphocytes ; AIDS ; HIV ; Immunodeficiency ; Scanning electron microscopy ; SIV ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: The ultrastructural features of AA-2 cells infected with either of two strains of simian immunodeficiency virus (SIVMne-E11S or SIVSMM-PBj) were examined by scanning electron microscopy (SEM). Transformed CD4+ human B lymphocytes (AA-2) were inoculated with SIV and observed at 2, 4, and 7 days post-inoculation (dPI). Infected AA-2 cells were distinguished by the progressive loss of microvilli, and variable numbers of free or protruding spherical particles measuring 90-120nm in diameter along the cell surface. Syncytial cell formation (complexes of fused cells) and necrotic cells were evident at each time point with the most numerous observations at 7 dPI. While the distribution and severity of the viral induced changes increased with time and affected virtually all cells by 7 dPI, the alterations were detected sooner and were more pronounced in SIVSMM-PBj infected cells. This finding is consistent with the in vivo data from primate studies using the same strains of SIV. Syncytial cells exhibited slight to moderate indentations which appeared to coincide with the boundaries of individual cells forming the complex. The plasma membrane of syncytial cells was relatively smooth and lacked microvilli. Spherical particles and buds protruding from the plasma membrane were predominate features of syncytial cell surfaces. By the employment of antisera generated against whole SIVMne-E11S, both transmission and scanning immunoelectron microscopy confirmed the identity of the spherical structures as free and budding SIV virions. © 1994 Wiley-Liss, Inc.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 25 (1993), S. 503-508 
    ISSN: 1059-910X
    Schlagwort(e): Intermetallic compounds ; ESEM ; SEM ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Copper samples, hot solder (eutectic) dipped and thermally aged, were cross-sectioned and placed in an environmental scanning electronic microscope (ESEM). While in the ESEM the samples were heated for ∼ 2.5 h at 170°C to stimulate the growth of additional Cu/Sn intermetallic compound. The intent of the study was to obtain a continuous real-time videotape record of the diffusion process and compare the observations to static SEM images reported to represent long-term, naturally aged intermetallic growth. The video obtained allows the observation of the diffusion process and relativistic growth phenomena at the Cu, Cu3Sn, Cu6Sn5, and solder interfaces as well as effects on the bulk Cu and solder. Effects contrary to earlier reports were observed; for example, growth rates of Cu3Sn were found to greatly exceed those of Cu6Sn5. © 1993 Wiley-Liss, Inc.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 11
    ISSN: 1059-910X
    Schlagwort(e): Image analysis ; Respiratory cells ; SEM ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: This paper describes the coupling between a scanning electron microscope (SEM) and an image analysis workstation. The system was designed in order to drive the SEM and to analyse any sample. It allows automatic (edge detection) or semiautomatic (pointing, marking, drawing) object detection. Two types of data can be obtained: (1) topographical information, such as the location of the object within a region of interest drawn at any magnification of the microscope, or (2) quantitative data, such as morphometric characteristics of objects. In addition, high resolution maps of the section, regions of interest, and objects can be obtained with a laser printer. This software was first applied to quantitate the adhesion of the bacteria Pseudomonas aeruginosa to human respiratory epithelial cells in culture. P. aeruginosa was shown associated with ciliated cells. The second application concerned the study of the distribution of specific carbohydrate residues at the surface of the respiratory cells. The gal residues were revealed using the lectin Ricinas communis agglutinin II, adsorbed to colloidal gold particles. A relationship between the presence of adherent bacteria and labelling was shown. © 1993 Wiley-Liss, Inc.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 12
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 26 (1993), S. 133-141 
    ISSN: 1059-910X
    Schlagwort(e): Taste ; Secretion ; Microvilli ; Freeze-substitution ; Freeze-fracture deep-etching ; Electron microscopic cytochemistry ; Colloidal gold ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Thaumatin is a protein that tastes intensely sweet only to Old World monkeys and to higher primates, including man. Here we used pre-embedding ultrastructural methods to study the distribution of thaumatin in apical regions of Rhesus monkey foliate papillae, using thaumatin conjugated to 5 nm gold particles. With freeze-substitution we saw that gold-labeled thaumatin bound to an electron-opaque, sponge-like secretory substance inside the taste bud pores. Labeled thaumatin was found at the surface of the secretory substance even deep inside the pore, where other, unlabeled cellular structures surrounded the substance. With freeze-fracture deep-etching the secretory substance that bound the thaumatin-gold particles appeared coarsely granular. There was no labeling of any other taste bud pore structure, including microvilli and small membranelined vesicles. Pre-incubation with an excess of unlabeled thaumatin inhibited binding with goldlabeled thaumatin. The results suggest that the secretory substance had the greatest affinity of all taste pore structures to the sweet-tasting compound under our experimental conditions. Therefore, gustatory reception probably involves various taste compound binding structures, microvilli, and also secretory substances like the one described here which bound thaumatin. We speculate that the secretory substance may bind taste stimuli and serve as an intermediate between stimuli and receptors. It could be involved in stimulus removal or delivery or both. © 1993 Wiley-Liss, Inc.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 13
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992), S. 160-169 
    ISSN: 1059-910X
    Schlagwort(e): Freeze-fracture and cytoplasmic maceration ; Chloroplasts ; Pollen ontogeny ; SEM ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: The application of the freeze-fracture and cytoplasmic maceration technique in ultrastructural studies of plant cells is described. A major advantage of the technique is, that by extracting mobile cytoplasmic components from the freeze-fractured cells, surface relief is introduced and three-dimensional information is obtainable. The details of specimen preparation are described and the results obtained are reviewed. The use of chitosan embedding for very small or fragile specimens is described. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 21 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 14
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992), S. 130-150 
    ISSN: 1059-910X
    Schlagwort(e): Electron microscopy ; Scanning electron microscopy ; High resolution ; Cytoskeleton ; Biological specimen preparation ; Cultured cells ; Electrophoresis ; Bifunctional crosslinking reagents ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Today's electron microscopes have a resolution sufficient to resolve supramolecular structures. However, the methods used to prepare biological samples for electron microscopy often limit our ability to achieve the resolution that is theoretically possible. We use whole mounts of detergent-extracted cells grown on Formvar-coated gold grids as a model system to evaluate various steps in the preparation of biological samples for high resolution scanning electron microscopy (SEM)Factors that are important in determining the structure and composition of detergent-extracted cells include the nature of the detergent and the composition of the extraction vehicle. Chelation of calcium is extremely important to stabilize and preserve the cytoskeletal filaments. We have also demonstrated both morphologically and by gel electrophoresis that treatment of cells with bifunctional protein crosslinkers before or during extraction with detergent can significantly enhance the preservation of both proteins and supramolecular structures.The methods used to dry samples are a major determinant of the quality of structural preservation. For cytoskeletons freeze-drying (FD) is superior to critical point-drying (CPD), one reason being that CPD samples have to be dehydrated, thereby causing more shrinkage as compared to FD samples. The high pressures to which samples are exposed during CPD may also cause increased shrinkage, and water contamination during CPD causes severe structural damage. We have obtained the best structural preservation of detergent-extracted and fixed cells by manually plunging them into liquid propane and drying over night in a freeze-drayer.The factor that most limits achievement of high resolution in SEM is the metal coat, which has to be very thin, uniform, and free of grain in order not to hide structures or to create artifactual ones. We have found that sputter-coating with 1-3 nm of tungsten (W) or niobium )Nb( gives extremely fine-grained films as well as satisfactory emission of secondary electrons. These samples can also be examined at high resolution by transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). The best preservation and visualization of supramolecular structures have been obtained using cryosputtering, in which the samples are freeze-dried and then sputter-coated within the freeze-dryer while still frozen. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 15
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 20 (1992), S. 288-297 
    ISSN: 1059-910X
    Schlagwort(e): SEM ; TEM ; Guinea pig ; Cochlea ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Inner ear tissue of the normal guinea pig was conductively stained (OTOTO-method) for SEM investigations. The Hensen's cells of the organ of Corti were removed using a micromanipulator inside the SEM. By this method atypical bodies of sensory and supporting cells were revealed in the apical turns of the cochlea. Atypical sensory cells showed great variations in size and shape. Several had no contact to Deiter's cells and no or only one nerve supply at their basal end. Atypical Deiter's cells showed alterations in shape and in the form of their phalangeal processes.Additionally altered parts of the organ of Corti were isolated by micromanipulation and embedded for correlative TEM-investigations.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
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  • 16
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 23 (1992), S. 225-229 
    ISSN: 1059-910X
    Schlagwort(e): Scanning electron microscopy ; Ultrastructure ; Zona pellucida ; Mucus ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: The fine structure of the zona pellucida (ZP) covering the oocyte and of the mucus covering the surface of the intestinal villi was investigated by using a new method employing ruthenium red (RR), saponin, and osmium-thiocarbohydrazide impregnation.The glycoproteic matrices both appeared constituted by thin filaments (ranging from 22 to 50 nm in thickness) anastomosed to form a very fine network.RR prevented the dissolution and/or alteration of glycoproteins and polyanionic carbohydrates induced by acqueous fixatives. Saponin was a detergent of the soluble proteins. Osmium-thiocarbohydrazide preserved the glycoproteic matrix filaments from the mechanical stress induced by dehydration and critical point drying and reduced filaments packing and shrinkage. The technical improvement was demonstrated by the following results: 1) a regular arrangement of the filaments network; 2) a thickness of mucus filaments smaller than that obtained with other methods of preparation; 3) a homogeneous thickness of ZP filaments.This method allowed a very detailed study of the fine structural organization of the ZP and intestinal mucus. Therefore, this technique can be useful for a better evaluation of the morphodynamic of these and other glycoproteic matrices. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 17
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 17 (1991), S. 81-94 
    ISSN: 0741-0581
    Schlagwort(e): Colloidal gold ; Pathogenesis-related (PR) proteins ; Tobacco plants ; Hypersensitivity ; Tobacco mosaic virus ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Immunocytochemical techniques are confronted with the problem of obtaining adequate tissue preservation together with retention of protein antigenicity. Various methods, including freeze-drying and freeze-substitution, have been devised to circumvent this problem. In the present study, we report that microwave energy used in combination with low concentrations of glutaraldehyde (0.1%) and paraformaldehyde (2%) preserves the structural integrity of plant tissue and antigenicity of proteins. Tobacco leaf samples fixed in a time as brief as 15-20 s exhibited excellent preservation of fine structures. By contrast, specimens irradiated for shorter (5-10 s) or longer (30-40 s) periods showed poor morphological preservation. Microwave irradiation for 15-20 s was found useful for immobilizing large amounts of soluble antigens. The fast microwave fixation method was successfully used to preserve pathogenesis-related (PR) proteins, which were subsequently localized by a postembedding immunogold procedure. In addition to soluble antigens, cellulose subunits and pectic substances, two major plant cell wall components, were found to be highly preserved in microwave-irradiated tobacco plant tissue. The present study demonstrates that microwave fixation of plant tissue is a simple and inexpensive method that is easy to perform with commercially available microwave ovens. The incubation time for fixation is reduced from 2 h to 15-20 s without loss of fine structural details. This method will undoubtedly acquire increasing applicability and relevance in plant biology.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 18
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 18 (1991), S. 126-134 
    ISSN: 0741-0581
    Schlagwort(e): Sequential extraction ; Whole-mount cell ; Monoclonal antibody ; Colloidal gold ; Cross-reaction ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Whole-mount, sequentially extracted cells combined with immunogold electron microscopy were developed to demonstrate the intermediate filaments, lamina, and nuclear matrix (IF-L-NM) and to identify their protein components. The IFs of HeLa cells were reacted both with keratin and vimentin monoclonal antibodies; meanwhile, the IF network of BHK-21 cell was reacted only with vimentin monoclonal antibody. The lamina and nuclear matrices of both HeLa and BHK-21 cell were labelled, respectively, with lamin monoclonal antibody-gold complex and 280 Kd nuclear matrix protein monoclonal antibody-gold complex. The monoclonal antibody to keratin could cross-react with the lamina both of HeLa and BHK-21 cells.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 19
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 18 (1991), S. 197-202 
    ISSN: 0741-0581
    Schlagwort(e): Graft ; Transplant ; Labeling ; Colloidal gold ; Sendai virus ; Cortex ; Nucleus basalis ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: The ability to discriminate between host and donor cells is required to interpret the organization of neural grafts at the electron microscopic (EM) level. Using light microscopy, Ardizzoni et al. (Ardizzoni, S.C., Michaels A., and Arendash, G.W. [1988] Science 239: 635-637) described a method, using gold-filled Sendai viral envelopes, for labeling cell suspensions prior to grafting. As the colloidal gold used in this procedure is especially attractive for use with EM, we have examined the ultrastructural distribution and character of this label with transplanted cells. Cell suspensions taken from the nucleus basalis of fetal rats were labeled using gold-filled Sendai viral envelopes and grafted into the dorsal neocortex of adult host rats with nucleus basalis lesions. After varying survival times ranging from 1 to 14 months, grafts and surrounding host tissue were examined using standard EM techniques. Within the graft site, gold particles ranging from 10-200 nm were found associated with various membranes throughout the cytoplasm of both neurons and glia. Gold particles of similar size were also found within the nuclei of neuronal and non-neuronal cells. Host cells near the graft site contained some small gold particles (10-40 nm). Control injections of non-viable, gold-labeled cells or colloidal gold alone resulted in similar patterns of small gold particles which were readily discriminable from the larger virally inserted gold particles found in viable labeled donor cells. We conclude that this method allows discrimination between closely associated host and donor cells.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 20
    ISSN: 0741-0581
    Schlagwort(e): SEM ; Intestinal morphology ; Intracellular structure ; Mitochondria ; Cell membrane ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Improvements in the design of modern scanning electron microscopes (SEM) and new methods of specimen preparation incorporating chemical removal of the cytosol and cytoskeleton, now make it possible to view cells and their organelles in three dimensions (3D) at high magnification. In this experiment, high resolution SEM (HRSEM) utilizing new methods of tissue preparation was used to study the intracellular structures of the mouse ileum. In addition, in vivo intestinal perfusion was used to further enhance cellular preservation. Using these modifications it was possible to visualize, in 3D, the fine structure of intestinal epithelial cells and intracellular organelles such as the nucleus, mitochondria, endoplasmic reticulum, and Golgi complex, as well as microvilli and cell membrane. Whole mitochondria appeared as irregularly shaped organelles which contained tubular cristae. Plate-like cristae were not observed. The brush border was found to be a closely packed array of cylindrical projections. The extensive folding and structural intricacy of lateral cell membranes between absorptive cells could only be appreciated by viewing this tissue with 3D HRSEM. The use of HRSEM to study 3D ultrastructure of cells and their organelles will improve our understanding of the structure-function relationships in both the healthy and diseased gastrointestinal tract.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 21
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 18 (1991), S. 106-116 
    ISSN: 0741-0581
    Schlagwort(e): Cell monolayers ; Scanning electron microscopy ; Cell morphology ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: The ultrastructural characteristics of several growth matrices were examined using two cell types chosen for their distinct growth habits. Chinese hamster ovary cells and Balb-c 3T3 mouse fibroblasts were grown on flat substrates (glass, tissue culture plastic, Millipore filters) as well as spherical (glass, tissue culture plastic, cross-linked dextran) substrates. Cells were plated maintaining equal densities and growth surface area. Once the majority of the cells reached confluency, the cell's morphology on each matrix was examined using scanning electron microscopy. Digital analysis was performed on cell attachment area to compare the effect of each matrix on cell spreading.Variation in cell shape was dramatic between matrices, being most noticeable between a textured surface (filter, dextran bead) and that of a smooth (glass) surface. Even within smooth surfaces, some variation was observed. There was also an effect of matrix curvature on cell attachment area, the greatest being in the 3T3-c Balb cells, causing an overall decrease in the area of attachment between cell and matrix. The changes seen could also be related to the particular cell type used. Hamster ovary cells tended to be cylindrical and showed little effect between matrices, whereas the mouse fibroblasts, which are more flattened, showed the matrix effect to a greater degree.This study demonstrates the necessity of being aware of substrate-induced cell changes in tissue culture, where some variation in cell shape may be due to the surface on which the cells are grown as opposed to the experimental procedure.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 22
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 18 (1991), S. 121-125 
    ISSN: 0741-0581
    Schlagwort(e): Immunocytochemistry ; Colloidal gold ; Cerium chloride ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Immunoelectron microscopic localization of surface antigens on lymphocytes is possible using alkaline phosphatase combined with cerium-based cytochemical methods. Distinctive electron-dense deposits are easily identified at sites of antibody binding. Mouse splenocytes showing surface immunoglobulin localization and human peripheral blood lymphocytes stained for the MHC-Class II antigen HLA-DR illustrate the results. Double staining for murine Ia antigen by the alkaline phosphatase procedure, combined with immunogold labeling of antigens identified on dendritic cells, i.e., NLDC-145, demonstrates the utility of the cerium cytochemical method.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 23
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 19 (1991), S. 486-490 
    ISSN: 0741-0581
    Schlagwort(e): Alveoli ; SEM ; Stereo pair images ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Alkali digestion has been used to remove cellular elements of tissues thus exposing the underlying connective tissue framework. We studied the action of this severe alkali treatment on the delicate tissues of rat lung. The lungs of male Sprague-Dawley rats were perfused with saline to remove blood and then inflated by fixation through the airways at 20 cm pressure. Sections of lung 2 × 5 × 5 mm were immersed in 2.5 M NaOH at 25°C for 6 h, 16 h, 24 h, 48 h, and 72 h. The alkali was changed daily. Tissues were washed to neutral with water (24 h), treated with tannic acid (1%, 3h), post-fixed with osmic acid (1%, 3 h) and processed for SEM. At 6 h, epithelial cells started to peel off the alveolar surface. At 16 h the digestion process was well advanced. At 48 h the cells were completely removed revealing the lattice network of connective tissue fibers within the alveolar surface. The method allows the complete removal of cellular elements of the lung while retaining the very fine 3D structure of the connective tissue matrix.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 24
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 18 (1991), S. 50-60 
    ISSN: 0741-0581
    Schlagwort(e): Confocal microscopy ; Light microscopy ; Scanning electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: We have adapted a tandem scanning confocal microscope for real-time, non-invasive imaging of cells under in vivo conditions. This form of in vivo confocal imaging relies on the optical sectioning abilities of the confocal microscope to obtain en face, sequential, reflected light images of cells at various depths, up to 1 mm, within opaque organs in living animals. Of major consideration in the design of an in vivo confocal microscope is maximizing the real-time detection of signals reflected from low contrast structures which can be affected by the microscope design, objective, and image detector systems. Using an in vivo confocal microscope design with a 20 × BioOptics surface contact objective we have obtained live cellular images from selected tissues including cornea, kidney, liver, adrenal, thyroid, epididymis, and muscle and connective tissue of rabbits and rats. Images were captured, digitized, and processed using a DAGE Mti low light level SIT camera coupled to a Gould IP9527 image processor. In vivo images were also compared with conventional bright field light and scanning electron microscopic images of “dead,” fixed tissues. Overall, in vivo confocal imaging can provide remarkable detail of living cells comparable to that of conventional microscopic images of “dead,” fixed, and stained tissue. A more unique feature of in vivo confocal imaging is the ability to study cellular structure and function sequentially over time in the same organ or tissue and represents a fundamentally new paradigm in microscopy. With continued refinements in the microscope, objective and detection system designs and their consequent improvements in lateral and axial resolution, in vivo confocal microscopy will enable us as observers to see what no one has been able to see before.
    Zusätzliches Material: 25 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 25
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 19 (1991), S. 419-428 
    ISSN: 0741-0581
    Schlagwort(e): Hand skin ; Resin cast ; Capillary loops ; Scanning electron microscopy ; Changes with age ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: The microvasculature of the skin of the hand in primates, including man, was examined by means of scanning electron microscopy of corrosion casts. In this study, the microvascular patterns and structures in different areas of the hand, and the changes in vascular patterns that occur with age, have been described.The typical structure of the capillary loops in the hand can be observed in the ball of the finger of the young adult monkey. The capillary loops were formed out of not just one capillary vessel, but two or three vessels. Each capillary vessel arose and divided into several branches at the papillae, and these became descending limbs. After the loop passed a hairpin turn, the descending limbs were 1.5 times larger than the ascending limbs in the intrapapillary portion, and they became extrapapillary venules. The descending limbs connected with the postcapillary venules in the postpapillary portion and with the horizontal network. The postcapillary venules fused with each other to form the primary and secondary venous arcades. The secondary venous arcades anastomosed with each other and flowed into the subpapillary venules, which run along the dermal furrow in the fingerprint.Changes in vascular patterns with age could be observed. In the infant fingerprint, the vascular systems had not yet differentiated, especially the venous system in the dermis. In the old adult finger, the capillary loops presented complicated features deviating due to aging.
    Zusätzliches Material: 20 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 26
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 19 (1991), S. 189-202 
    ISSN: 0741-0581
    Schlagwort(e): Rat testis ; Irradiation ; Scanning electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Newly developed techniques in high-resolution scanning electron microscopy (SEM) and for tissue-processing procedures have been applied to an investigation of structures of various cells in rat testes at different stages of gonadal maturation. A series of high-resolution SEM micrographs are presented which survey the surfaces of different types of testis cells during normal development, and which also illustrate ultrastructural features of some of their intracellular organelles. In addition, a series of high-resolution SEM micrographs are presented which compare the structural features of Sertoli cells in normal testes with those in germ-cell-depleted testes obtained from rats killed at varying times after having been irradiated in utero. We describe our observations on the structural properties of surfaces and intracellular organelles in Sertoli cells, Leydig cells, peritubular myoid cells, and some classes of germinal cells. We also consider the possible role of Sertoli cell apical cytoplasmic processes in lumen formation. Similarities are pointed out between the structure of germ-cell-depleted testes, resulting from irradiation in utero, and the structure of germ-cell-depleted testes in seasonal breeders during periods of involution. Finally, we discuss advantages and disadvantages of methods employed to reveal the fine structure of intracellular organelles in cells of the testis.
    Zusätzliches Material: 31 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 27
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 15 (1990), S. 104-114 
    ISSN: 0741-0581
    Schlagwort(e): Nerve fiber ; Afferent and efferent nerves ; Cochlea ; Fetal inner ear ; Human ear ; SEM ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: The cochleas of four human fetuses ranging 22-25 weeks gestation were studied by scanning electron microscopy (SEM) for the purpose of obtaining a better understanding of the nerve fiber arrangement in the human ear. After critical point drying, the specimens were dissected and the floor of the tunnel of Corti and the outer wall of Nuel's space were exposed for observation. Upper cochlear turns, especially the apical turn, seemed to be still immature.Observed nerve fibers were classified into three types:1Spiral fibers: Fibers traveling basalward and following the shape of the cochlea were found in both the tunnel of Corti and Nuel's space and believed to be the afferent nerves responsible for innervating the outer hair cells2Radial fibers: radiating outward from the osseous spiral lamina - one such radial fiber transversing high in the tunnel space (supposedly the efferent nerve servicing the outer hair cells), and another sort of radial fiber (found crossing the tunnel floor), the nature of which was uncertain.3Irregular fibers: Consisting of thin, randomly running fibers within the cochlea. The destination of these fibers was not determined, but possibly they represent transitory nerve branchings of afferent or more probably efferent nerves, which would later regress during maturation.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 28
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 15 (1990), S. 245-260 
    ISSN: 0741-0581
    Schlagwort(e): Stereocilia ; Postmortem cochlea ; Scanning electron microscopy ; Human ; Guinea pig ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: The morphology of hair bundles has been studied by high resolution scanning electron microscopy using a variety of fixatives, including glutaraldehyde, glutaraldehyde-picrate, glutaraldehyde-tannic acid, glutaraldehyde followed by post-fixation in osmium tetroxide, and the osmium thiocarbohydrazide technique. Critical evaluation of several metal coatings, gold, gold-palladium, and platinum has been carried out.Both the surface texture of stereocilia and their cross-links are sensitive to fixation and metal coating. We are of the opinion that glutaraldehyde gives the best general quality of fixation and preservation for all types of cross-links. We have described three major sets of cross-links: first, lateral links connecting stereocilia within the same row; second, lateral links connecting stereocilia of adjacent rows; and third, upward-pointing links, one per stereocilium, connecting the tip of each shorter stereocilium to the lateral surface of the adjacent taller stereocilium. Current physiological and anatomical evidence suggests that the lateral links couple the individual stereocilia within the hair bundle so that they function as a single mechanical unit. The upward-pointing tip links are ideally placed to respond to mechanical deformation of the hair bundle, being stretched when the stereocilia are deflected in the excitatory direction towards the tallest row and relaxed when deflected in the opposite, inhibitory direction.Postmortem morphological changes are detected within 15 minutes of cardiac arrest and become progressively more pronounced in time. These results enabled us to distinguish specific druginduced changes which could not be attributed simply to cell death. Effects of cisplatin and kanamycin upon hair bundles are described. The work reported here is based on studies using the guinea pig cochlea. Some of the postmortem changes described have also been confirmed in human cochleas.It is stressed that many of the postmortem and drug-induced effects can only reliably be studied by high resolution scanning electron microscopy coupled with appropriate prearation procedures.
    Zusätzliches Material: 34 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 29
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 14 (1990), S. 1-5 
    ISSN: 0741-0581
    Schlagwort(e): Scanning electron microscopy ; Microanalysis ; Elemental mapping ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: A technique was developed to prepare archaeological fiber cross sections for electron microscopic examination and x-ray analysis. Use of this new method allows chemical and morphological information to be obtained from the interior of a single fiber or yarn. Fibers are fractured while frozen and then freeze dried. Following mounting and carbon coating, fibers are examined by scanning and backscatter electron microscopy and then analyzed by using energydispersive spectrometry. Elemental distribution is mapped by using image-processing software. In this report, the described technique is employed in the examination of ancient fibers from three different long-term storage environments (moist buried, dry buried, museum stored). Data obtained by examining the interior of fibers such as these provide insight into the conditions of a fiber's growth, the treatments applied during the fiber's processing and use, and the conditions in which the fiber was stored.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 30
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 14 (1990), S. 367-372 
    ISSN: 0741-0581
    Schlagwort(e): Scanning electron microscopy ; Basement membranes ; Colonic development ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: We have used two epithelial-stripping techniques in our studies of the basal lamina in the developing rat colon. The first involves prolonged osmication followed by sonication; the second uses chelation of calcium by EDTA followed by sonication. Both techniques remove the epithelium from the basal lamina; however, the EDTA/sonication technique appears to produce a cleaner adepithelial surface of the basal lamina. In addition, the fine structure of the basal lamina appears to be better preserved in specimens prepared by the EDTA/sonication technique. In contrast, the basal lamina of specimens prepared by the osmium/sonication technique has a shattered appearance that we believe is due to an increase in the fragility of the delicate fetal basal lamina.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 31
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 14 (1990), S. 298-306 
    ISSN: 0741-0581
    Schlagwort(e): Colloidal gold ; Critical point drying ; Hairy cell leukemia ; Interleukin-2 receptor ; Macrophages ; Lymphokine-activated killer cells ; Peldri II ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: For many years critical point drying (CPD) has been the method of choice for preparing cells for scanning electron microscopy (SEM). Described herein is a simple, efficient, inexpensive, reproducible, and safe procedure using Peldri II, a proprietary fluorocarbon compound that is solid at room temperature and a liquid above 25°C, as a sublimation dehydrant for processing specimens for SEM. The utility of Peldri II was demonstrated in studies using leukocytes from the blood of healthy donors and patients with leukemia as well as from long-term lymphoblastoid cell lines. The application of the proposed Peldri II procedure was further documented in SEM studies in which the expression and distribution of the interleukin-2 receptor (IL-2R) on leukocyte surface membranes was imaged using colloidal gold-labeled antibodies (i.e., immunogold). When compared with current SEM preparation procedures using CPD, Peldri II is a useful alternative that is thought to offer several important advantages.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 32
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 12 (1989), S. 60-64 
    ISSN: 0741-0581
    Schlagwort(e): SEM ; Nondestructive observation ; Intermixing ; Fine pattern ; Focused ion beam ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: As a microscale tool for observing GaAs-Alx Ga1-xAs heterostructures, backscattered electron (BE) images in the scanning electron microscope (SEM) were compared with conventional secondary electron (SE) images. BE images were found to be more sensitive to compositional differences between GaAs and AlxGa1-xAs and less sensitive to surface roughness. BE images have a spatial resolution of 10 nm or better. This method enables the nondestructive observation of ultrafine lateral periodic structures, such as quantum-well-wire (QWW) structures, fabricated by compositional disordering technology using focused Ga ion-beam (Ga-FIB) implantation into GaAs-AlxGa1-xAs material.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 33
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 11 (1989), S. 117-125 
    ISSN: 0741-0581
    Schlagwort(e): Scanning electron microscopy ; Peldri II drying ; Critical point drying ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: A new chemical, Peldri II, is evaluated as a compound for drying soft biological tissues for scanning electron microscopy. Peldri II, a fluorocarbon, is a solid at room temperature and is a liquid above 25°C. Cells or tissues are embedded in Peldri II by immersing them in the liquid form and allowing it to solidify. Once solidified, Peldri II will sublime with or without vacuum to dry tissues, probably without introducing surface tension. Several types of cells and tissues have been examined to compare preservation with Peldri II and critical point drying techniques. No differences were detected between the two techniques when normal surface structures were examined. Peldri II appears to be a significant improvement over hexamethyldisilazane as a drying agent for scanning electron microscopy. It is also very convenient for drying large numbers of samples.
    Zusätzliches Material: 17 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 34
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 11 (1989), S. 143-154 
    ISSN: 0741-0581
    Schlagwort(e): Detector systems for microdiffraction ; STEM imaging ; Coherent diffraction effects ; Image reconstruction from diffraction patterns ; EELS ; SEM ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: A two-dimensional detector system, designed for the observation and recording of microdiffraction patterns formed in an HB 5 scanning transmission electron microscope (STEM) is described and discussed. Possibilities are described and demonstrated for the simultaneous or successive recording of microdiffraction patterns from regions of diameter 3 å or more, bright- or dark-field STEM images, EELS spectra, secondary electron images, and in-line holograms. Applications of the system have been made to studies of catalyst particles, reflection-mode imaging of bulk surfaces, and image reconstruction from microdiffraction patterns obtained from each point of a STEM image.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 35
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 12 (1989), S. 155-159 
    ISSN: 0741-0581
    Schlagwort(e): Antibody ; Ultrahigh-resolution SEM ; Colloidal gold ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Using an ultrahigh-resolution scanning electron microscope (SEM), an attempt was made to directly visualize antibody molecules at antigenic sites in rat pancreas or on silicone plates. Although individual antibody molecules could not be discerned, a fluffy meshwork, probably indicating several molecules, was seen. With further improvements in specimen preparation, the high-resolution SEM promises to be an important tool in examining individual antibody-antigen sites without the need of an electron-dense label such as colloidal gold.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 36
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 12 (1989), S. 146-154 
    ISSN: 0741-0581
    Schlagwort(e): SEM ; Intracellular structures ; Bacteriophage ; Ferritin ; IgG ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: In 1985 we developed an ultrahigh-resolution scanning electron microscope with a resolution of 0.5 nm. It is equipped with a field emission gun and an objective lens with a very short focal length. In this study we report a survey of some different preparation techniques and biological specimens using the new scanning electron microscope.Intracellular structures such as cell organelles were observed surprisingly sharper than those observed by ordinary scanning electron microscopes. However, at magnifications over 250,000 X, platinum particles could be discerned as scattered pebbles on the surface of all structures in coated materials. Using an uncoated but conductively stained specimen, we successfully observed ribosomes on a rough endoplasmic reticulum at a direct magnification of 1 million. In these images some protrusions were recognized on the ribosomes.Ferritin and immunoglobulin G were used as samples of biological macromolecules. These samples were observed without metal coating and conductive staining. The ferritin particles appeared as rounded bodies without any substructure on the surface and immunoglobulin G as complexes of three-unit bodies. In the latter the central body might correspond to the Fc fragment and two side ones to Fab fragments.We assume that ultrahigh-resolution scanning electron microscopy is an effective means for observation of the cell fine structures and biological macromolecules. It will open a new research field in biomedicine.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 37
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 13 (1989), S. 175-203 
    ISSN: 0741-0581
    Schlagwort(e): Colloidal gold ; Replica ; Membrane structure ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: “Freeze-fracture cytochemistry” encompasses a diversity of recently developed techniques in which freeze-fracture and cytochemistry are combined. Cytochemical labeling may, in principle, be integrated into one of three basic points in the standard freeze-fracture procedure; (1) before the specimen is frozen, (2) after it has been fractured, or (3) after it has been platinum shadowed and/or carbon coated. Visualization of the labeled cellular structures can be achieved by a variety of different methodologies. For example, the markers (usually colloidal gold particles) may be viewed embedded within a replica, or attached to it via fragments of membrane (or other cellular components). Sectioning is a central strategy in a number of techniques, either in combination with or in place of replication. The different combinations of methods that have been devised are not, for the most part, alternative ways of arriving at the same result; each provides quite distinct information about specific classes of membrane component or other structure in the cell. The purpose of this review is to present, within a single article, a systematic survey of the full range of techniques currently available in freeze-fracture cytochemistry. Emphasis is placed on explaining the principles underlying the methods and on illustrating their applications. With the success recently achieved, freeze-fracture cytochemistry has moved from the phase of experimental development to a position in which it may be expected increasingly to make significant contributions across a wide spectrum of problems in cell and membrane biology.
    Zusätzliches Material: 20 Ill.
    Materialart: Digitale Medien
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  • 38
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 13 (1989), S. 216-227 
    ISSN: 0741-0581
    Schlagwort(e): Toad bladder ; Label fracture ; Colloidal gold ; Replica ; Membrane ; Freezing ; Glycocalyx ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Electron microscopic studies of membrane structure have been facilitated by the recent development of the composite replica technique in which the membrane is freeze-fractured, then inverted and the surface deep-etched and replicated. Examination in stereo of this composite preparation of two replicas with interposed half-membrane and associated surface elements reveals the physical relationship between structures on the surface and within the membrane. Composite replicas of the toad urinary bladder surface demonstrated connections of filamentous glycocalyx elements to intramembrane particles (IMPs). Using a bidirectional shadowing technique, many membrane surface particles also are shown to be associated with underlying IMPs, suggesting that these membrane surface particles are projections of the IMPs above the surface of the membrane. There is evidence that elements whose attachment sites relate to the half-membrane fractured away can be displaced from the membrane surface and lost. Labelling studies using colloidal gold-labelled antibodies were carried out to assess loss of surface mesh from fractured membrane. Gold distributions and amounts were similar in labelled surface replicas, label-fracture specimens, and labelled composite replicas, yet the amount of mesh detected in the composite replicas was less than in the surface replicas. This suggests that while some unlabelled or lightly labelled surface elements can be lost from fractured membranes, ligands stabilize elements and reduce their loss apparently by cross-linking them.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 39
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 10 (1988), S. 15-26 
    ISSN: 0741-0581
    Schlagwort(e): Scanning electron microscopy ; Ocular microvasculature ; Microcorrosion cast ; Injection replica ; Batson's ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: We have refined the technique of vascular corrosion casting with methacrylate to permit the reproduction of physiological states of vascular tone and to produce sturdy castings of ocular microvasculature. The method entails careful maintenance of homeostasis up to the moment of plastic perfusion, avoidance of vascular rinsing or fixation with the attendant anoxia, reduction of the viscosity of the casting resin without impairing the properties of the resultant polymer, addition of a cross-linking agent to increase the strength of the plastic, and injection at physiological temperature and pressure. This casting regimen reproduces the normal anatomical conditions of blood vessels and can be used to demonstrate altered conditions of vascular tone. In all instances, the second, untouched eye serves as a control for unilateral manipulations. Special problems of replicating the ocular vasculature are related to the intraocular pressure, which opposes the vascular perfusion pressure and constitutes an impediment to perfusion.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 40
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 8 (1988), S. 371-379 
    ISSN: 0741-0581
    Schlagwort(e): Casuarina ; Cellulase ; Cell walls ; Codium ; Colloidal gold ; Dictyostelium ; Udotea ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: The enzyme-linked colloidal gold affinity labelling technique was tested as a method to localize cellulose on thin sections of plant cell walls and slime mold spores. Commercially available cellulase from cultures of Trichoderma reesei, the main components being cellobiohydrolase I and II (CBH I, CBH II) and endoglucanase (EG), was linked to colloidal gold by using standard techniques and applied as a dilute, buffered suspension to thin sections. After brief exposure, e.g., 15-30 minutes, cellulose exposed on the surface of sections was labelled with the enzyme-gold complex. Poststaining did not appear to have a deleterious effect on the labelled sections. The specificity of labelling was demonstrated by its complete inhibition when carboxymethylcellulose was incorporated in the labelling mixture, by lack of labelling of 1,4-β-mannans or 1,3-β-xylans in noncellulosic walls of marine algae, by lack of labelling of 1,4-β-glucans in chitin, by much lower labelling density when done at 4°C, and by lack of labelling when sections were predigested with cellulase. Labelling with the crude commercial cellulase was compared to labelling with purified CBH I-, CBH II-, and EG-linked colloidal gold, and the labelling pattern was similar. This method was found useful on conventionally fixed material and required no special preparation other than the use of inert (Ni or Au) grids and 0.5% gelatin to reduce nonspecific binding of the gold complex. Labelling was similar in the several embedding resins tested: LR White, Lowicryl K4M, Epon 812, and Spurr's. The cellulase-gold probe remained active for at least 4 weeks at 4°C and much longer when frozen at -80°C in 20% glycerol. This technique should prove useful in studies of cellulose degradation and cellulose deposition and of the interaction of cellulose with other wall components.
    Zusätzliches Material: 17 Ill.
    Materialart: Digitale Medien
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  • 41
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 9 (1988), S. 187-208 
    ISSN: 0741-0581
    Schlagwort(e): Transmission electron microscopy ; Scanning electron microscopy ; Morphometry ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: The relationship between structure and function in the distal tubule and collecting duct has been studied with morphologic and physiologic techniques, including morphometric analysis, to identify functionally distinct cell populations. The distal tubule, including the thick ascending limb (TAL) and the distal convoluted tubule (DCT), is involved in active reabsorption of sodium chloride. It is characterized by extensive invaginations of the basolateral plasma membrane, numerous mitochondria, and high Na-K-ATPase activity, features characteristic for an epithelium involved in active transport. Between the distal tubule and the collecting duct is a transition region, the connecting segment or the connecting tubule (CNT), which exhibits species differences with respect to both structure and function. The collecting duct includes the cortical (CCD), the outer medullary (OMCD), and the inner medullary (IMCD) collecting ducts. Principal cells are present throughout the collecting duct, whereas intercalated cells are located mainly in the CCD and OMCD. Morphometric analysis combined with micropuncture and microperfusion studies has provided evidence that the CNT and principal cells are responsible for potassium secretion in the connecting segment and the CCD. The OMCD is a main site of hydrogen ion secretion, and morphometric studies have provided evidence that the intercalated cells in this segment secrete hydrogen ion at least in the rat. Two configurations of intercalated cells exist in the CCD - a type A and a type B. The A cells are similar in ultrastructure to the intercalated cells in the OMCD and are believed to be involved in hydrogen ion secretion. The function of the B cells remains to be established. The inner two-thirds of the IMCD corresponds to the papillary collecting duct, which has a high permeability to urea. The relationship between structure and function in the IMCD has not been studied in detail. This review emphasizes the role of morphometric analysis in establishing the relationship between structure and function in the distal nephron.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 42
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 8 (1988), S. 185-191 
    ISSN: 0741-0581
    Schlagwort(e): Histologic techniques ; Scanning electron microscopy ; Blood vessels ; Pulmonary circulation ; Microcirculation ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Although techniques for preparing specimens for light and electron microscopy are well established, few studies have sought to establish methods for corrosion casting of the microscopic vessels of the lung. The effects of two concentrations of glutaraldehyde, formaldehyde, and no fixative (saline control) on the filling and structure of the microvascular casts of the lung were studied. All fixatives were infused 5 minutes before casting.Formaldehyde's fixation effects were intermediate between those of glutaraldehyde and no fixation. Leakage of casting material was increased in the animals that were fixed less. Digestion time was prolonged and more undigested tissue was found in the group receiving the concentrated glutaraldehyde, although the difference in neither of these features alone reached statistical significance. Circumferential bands occurred more frequently in the large vessel casts of the less fixed animals, which may account for the less filling microvasculature in these lungs. However, good quality casts were obtained with each method.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 43
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 5 (1987), S. 159-169 
    ISSN: 0741-0581
    Schlagwort(e): Monolayer cells ; Microcarrier beads ; Transmission electron microscopy ; Scanning electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: 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.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 44
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 6 (1987), S. 335-348 
    ISSN: 0741-0581
    Schlagwort(e): Digestive techniques ; Vascular elastic networks ; SEM ; Blood vessels ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: 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.
    Zusätzliches Material: 17 Ill.
    Materialart: Digitale Medien
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  • 45
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 7 (1987), S. 1-16 
    ISSN: 0741-0581
    Schlagwort(e): External determinants ; Colloidal gold ; High-voltage electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: 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.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 46
    ISSN: 0741-0581
    Schlagwort(e): Immunocytochemistry ; Electron microscopy ; Colloidal gold ; Glial fibrillary acidic protein ; Neuron-specific enolase ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: A postembedding immunocytochemical technique is described that allows ultrastructural localization of glial fibrillary acidic protein and neuron-specific enolase on tissues originally processed only for routine light and electron microscopy. Use of the oxidizing agent sodium metaperiodate prior to incubation with the primary antiserum sufficiently removes osmium tetroxide (OsO4) from potential antigen - antibody combining sites to allow specific localization of these neural antigens by colloidal gold immunolabelling. Both human and monkey neural tissues, prepared for routine ultrastructural examination with aldehyde fixatives and OsO4 postfixation, show excellent ultrastructural morphology and antigen localization. In addition, formalin-fixed, paraffin-embedded pathological human brain tissues, obtained at autopsy up to 22 years previously, show good ultrastructural immunolocalization of glial fibrillary acidic protein when re-embedded for electron microscopy. Thus, ultrastructural immunolocalization of certain neural antigens is easily achieved in tissues originally processed for routine light and electron microscopy. This allows re-examination of archival tissues using current immunocy-tochemical advances, including that of selected pathological tissues previously prepared solely for light microscopy.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 47
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 6 (1987), S. 7-13 
    ISSN: 0741-0581
    Schlagwort(e): Protein G ; Colloidal gold ; Protein G-gold ; Immuocyto-chemistry ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Protein G, an immunoglobulin G-binding molecule, was tagged with colloidal gold particles and was applied in immunocytochemistry. The present study reports the conditions required for the preparation of the protein G-gold complex and for its application in electron microscopy. Once used in combination with specific primary antibodies, the protein G-gold complex was able to yield highly specific labelings over particular tissue compartments. Various control experiments confirmed the specificity of the labelings obtained. Since the IgG-binding properties of protein G are superior to those displayed by protein A, the protein G-gold appears a far better tool for high-resolution immunocytochemistry.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 48
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 6 (1987), S. 35-41 
    ISSN: 0741-0581
    Schlagwort(e): Technique ; SEM ; Histology ; Polyester wax ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Steedman's polyester wax mixture is a good, general-purpose histological embedding medium that is suitable and convenient to use when it is desirable to combine light microscopy with scanning electron microscopy (SEM). A range of properties recommend this wax: it has a low melting temperature (37°C), is readily soluble in most dehydrating agents, results in negligible tissue shrinkage, preserves tissue antigenicity, and may even be used as a solvent for fixative agents. We prepare and embed tissues in polyester for light microscopy much as they would be for paraffin wax. For SEM, the block surface is micro- or ultraplaned, utilizing, respectively, a standard rotary microtome with razor blade knives or an ultramicrotome with glass knives. The block is de-waxed in absolute alcohol and then taken to critical point drying. Similarly, sections mounted on coverslips or glass slides may be brought to the SEM after removing the wax. This enables one to bring to the SEM relatively large block faces or sections with good control over orientation. We find the results to be superior to similar procedures employing paraffin. We believe it to be more versatile and equivalent or superior to a variety of other techniques designed to gain access to the interior of tissues with SEM.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 49
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 5 (1987), S. 65-74 
    ISSN: 0741-0581
    Schlagwort(e): Scanning electron microscopy ; Low temperature ; Microanalysis ; Duodenum ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Microanalysis data obtained using low temperature scanning electron microscopy of frozen hydrated etched mouse duodenum gives information about peak/background ratios of various elements in different cellular compartments. The present paper describes ways in which the data can be analyzed to minimize artifactual variations and to make clear where there are genuine differences in peak/background ratios when readings from different animals are compared. Using these methods, it is shown that in some areas of villous epithelium there are measurable differences in the ratios of sodium, calcium, and sulphur.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 50
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 5 (1987), S. 263-273 
    ISSN: 0741-0581
    Schlagwort(e): Immunocytochemistry ; Cell culture ; Cytoskeleton ; Scanning electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: This technique permits the visualization of microtubules in situ by employing silver-enhanced immunogold labeling and backscattered electron imagery. For best results, monolayer cultures of PtK2 cells are lysed with Triton X-100 in a microtubule stabilizing buffer, fixed with 1% glutaraldehyde, reduced with NaBH4, incubated with monoclonal antitubulin and 5-nm gold-labeled anti-IgG, silver enhanced, freeze dried, lightly coated with aluminum, and examined in an SEM equipped with a backscattered electron detector. A high contrast view of the entire microtubule complex of each cell is obtained. Microtubules in freeze-dried preparations have relatively smooth surfaces, whereas those in critical point dried preparations are more irregular or beaded. At high magnifications, an unstained inner core of each microtubule can be resolved. Backscattered electron imaging appears to be a promising technique for localizing cytoskeletal proteins and other intracellular antigens that can be labeled with immunogold and enhanced with silver.
    Zusätzliches Material: 20 Ill.
    Materialart: Digitale Medien
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  • 51
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 6 (1987), S. 31-34 
    ISSN: 0741-0581
    Schlagwort(e): Scanning electron microscopy ; Recording SEM images ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Described here is the construction of two 35-mm camera adaptors for attachment to the recording monitors of scanning electron microscopes (SEM). The designs are simple and readily adaptable to almost any SEM. The choice of this camera format for recording SEM images is one of convenience as well as economy and does not sacrifice micrograph quality.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 52
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 4 (1986), S. 371-379 
    ISSN: 0741-0581
    Schlagwort(e): Scanning electron microscopy ; Low temperature ; Microanalysis ; Duodenum ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: 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.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 53
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 3 (1986), S. 407-411 
    ISSN: 0741-0581
    Schlagwort(e): Mucus removal ; Nasal epithelium ; Rat ; Scanning electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: The surface layer of mucus, which obscures the epithelium from view, is a major obstacle when performing scanning electron microscopic studies of the nasal mucosa. Samples treated with a 1% mixed glycosidase solution for 1 or 2 minutes, followed by agitation, removed most of the mucus from the conchae without damaging the underlying epithelium. Removal of mucus allows the complete evaluation of the underlying epithelium in normal animals and the localization and characterization of lesions in animals exposed to nasal toxicants.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 54
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985), S. 201-208 
    ISSN: 0741-0581
    Schlagwort(e): SEM ; Rapid freezing ; Osmium ; Dimethyl sulfoxide ; Intracellular structure ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: 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.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 55
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985), S. 581-588 
    ISSN: 0741-0581
    Schlagwort(e): Bacterial identification ; Light microscopy ; Scanning electron microscopy ; Transmission electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: 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.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 56
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985), S. 403-404 
    ISSN: 0741-0581
    Schlagwort(e): Endothelial cells ; Fibrinogen ; Scanning electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 57
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985), S. 489-495 
    ISSN: 0741-0581
    Schlagwort(e): Embedment media ; Coagulant and noncoagulant fixatives ; Intracellular surfaces ; Scanning electron microscopy ; Thick sections ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Conventional plant histological specimens fixed in formalin-acetic acid-alcohol, chromic acid-acetic acid-formaldehyde, or glutaraldehyde-osmium and embedded in either paraffin or plastic are examined as possible rapid methods for providing an alternative image of cellular structure by using scanning electron microscopy. Using the mitotic figures of actively growing onion root tips as a study specimen, the organization of the nucleus and spindle apparatus is reasonably well preserved as compared with isolated mitotic spindles and studies of mitosis in endosperm tissue. Relief of internal structure in this technique is obtained through the coagulant nature of the fixative. Used judiciously, this technique can reveal aspects of the three-dimensional nature of internal tissue structure that may otherwise be difficult to discern.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 58
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985), S. 279-280 
    ISSN: 0741-0581
    Schlagwort(e): Endothelial cells ; Fibrinogen ; Scanning electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
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