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  • Articles  (115)
  • Electron microscopy  (115)
  • Wiley-Blackwell  (112)
  • Springer  (3)
  • American Chemical Society
  • Hindawi
  • Natural Sciences in General  (112)
  • Technology  (3)
  • 1
    Electronic Resource
    Electronic Resource
    The effect of the illumination time when treating port-wine stains (1995)
    Springer
    Lasers in medical science 10 (1995), S. 93-104 
    Details
    ISSN: 1435-604X
    Keywords: Copper vapour laser ; Electron microscopy ; Illumination time ; Numerical modelling ; Optimal treatment ; Port-wine stain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics , Technology
    Notes: Abstract This paper reports the electron microscopy results obtained from two patients who were treated with 5 W of yellow (578 nm) light from a copper vapour laser with an illumination time of 3.6 ms and a 0.3 mm spot diameter. The endpoint of treatment was transient blanching. Following treatment, erythema was observed. There was minimal damage to the epidermis and non-vascular tissue such as the nerve fibres. There was severe damage to the endothelial cells of the ectatic vessels. Twenty-four hours after treatment, platelet activation and collagen were present, indicating that these vessels were no longer viable. Theoretical calculations are used to determine the flow of heat within and away from a 50μm diameter vessel. From this, heating of the entire vessel is shown to occur with illumination times of 4 ms, with minimal heating of the non-vascular tissue. Shorter illuminations do not heat the entire vessel, while the use of longer illumination times will cause excessive damage to the surrounding non-vascular tissue. Illumination times close to 4 ms must be regarded as optimal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02150846
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  • 2
    Electronic Resource
    Electronic Resource
    Histomorphological aspects of vascular anastomosis established by laser (1991)
    Springer
    Lasers in medical science 6 (1991), S. 363-366 
    Details
    ISSN: 1435-604X
    Keywords: Laser vascular welding ; Tissue fusion ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics , Technology
    Notes: Abstract The central problem in microsurgery is the reconstruction of small vessels. The long operating time, foreign body granuloma formation around the suture material as well as aneurysmal alterations of the vessel wall after conventional suture technique make the search for alternatives indispensable. Some of these disadvantages can be avoided as demonstrated by our animal experiments and histological examinations in laser-assisted anastomosing. The aim of this study is to show these aspects in connection with laser application and compare them with conventional suture techniques.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02030894
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  • 3
    Electronic Resource
    Electronic Resource
    Biocompatibility of MPC: in vivo evaluation for clinical application (2000)
    Springer
    Journal of artificial organs 3 (2000), S. 39-46 
    Details
    ISSN: 1619-0904
    Keywords: Poly(2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate) (MPC) ; In vivo biocompatibility ; Artificial endocrine pancreas ; Electron microscopy ; Glucose sensor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract Biocompatibility is important to assure a mild body reaction to an implanted device and its long-term stability and functionality. In diabetes research, subcutaneously implanted glucose monitoring systems need biocompatible surfaces for long-term application. The biocompatibility of poly(2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate) (MPC), a material similar to the phospholipid layer of a cell membrane, was compared in vivo with the biocompatibility of polyurethane (PU), polyvinyl alcohol (PVA), and cuprophane (CUP). Needle-type glucose sensors and hollow-fiber probes used for microdialysis were coated with these four different biomaterials and implanted subcutaneously in 18 rats and 7 healthy volunteers. At set intervals, the implants and, in the case of the rats, also the surrounding tissue were removed and characterized by light and electron microscopy. MPC-coated sensors and hollow-fiber probes showed smooth and thin deposits in flat layers, whereas the surface deposits on PU- and PVA-coated sensors and those on CUP hollow-fiber probes appeared as rough, irregular, and dense attachments of aggregated cells and protein. This study confirmed results from earlier in vitro tests by showing the biocompatibility and reliability of MPC. Even though the amount of protein and cells attached to the MPC surface was not as low as expected from in vitro experiments, the biocompatibility and long-term stability of the implanted devices were superior to those of PU, PVA, and CUP.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02479925
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  • 4
    Electronic Resource
    Electronic Resource
    A personal computer based implementation of the maximum-likelihood method of analysis of electron microscope autoradiographs (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 20 (1992), S. 73-86 
    Details
    ISSN: 1059-910X
    Keywords: Electron microscopy ; Autoradiography ; Maximum-likelihood estimation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The maximum-likelihood (ML) method for the quantitative analysis of electron-microscopic autoradiographs has been shown to be substantially superior to the conventional crossfire (CF) method. It can generate reliable and accurate tracer concentration estimates with far fewer micrographs and produce valid estimates even at counts low enough to preclude the use of the crossfire method while eliminating the need for special ad hoc treatment of narrow membranous structures as well as the secondary verification of the tracer concentration estimates.Despite these significant advantages, the large computational requirements of the ML method has to date hampered its widespread use. In this paper, we present a new line-integration method that allows us to reduce the computational requirements of the ML method to a point where it becomes feasible to implement it on a small computer system of the type typically available to a laboratory user of EM autoradiography. We present the complete line-integration method for the particular case of EM autoradiography with tritium, and show how it can be adapted to other isotopes.We have constructed a software package that implements the complete maximum-likelihood method on the IBM PC class of machines using our line-integration method. Features of this software package which are of particular importance to the research community are device independence, which makes it usable with a large variety of currently available laboratory equipment, and easy portability of the software and data between different computer systems.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070200108
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  • 5
    Electronic Resource
    Electronic Resource
    Preservation and visualization of molecular structure in detergent-extracted whole mounts of cultured cells (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992), S. 130-150 
    Details
    ISSN: 1059-910X
    Keywords: Electron microscopy ; Scanning electron microscopy ; High resolution ; Cytoskeleton ; Biological specimen preparation ; Cultured cells ; Electrophoresis ; Bifunctional crosslinking reagents ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Today's electron microscopes have a resolution sufficient to resolve supramolecular structures. However, the methods used to prepare biological samples for electron microscopy often limit our ability to achieve the resolution that is theoretically possible. We use whole mounts of detergent-extracted cells grown on Formvar-coated gold grids as a model system to evaluate various steps in the preparation of biological samples for high resolution scanning electron microscopy (SEM)Factors that are important in determining the structure and composition of detergent-extracted cells include the nature of the detergent and the composition of the extraction vehicle. Chelation of calcium is extremely important to stabilize and preserve the cytoskeletal filaments. We have also demonstrated both morphologically and by gel electrophoresis that treatment of cells with bifunctional protein crosslinkers before or during extraction with detergent can significantly enhance the preservation of both proteins and supramolecular structures.The methods used to dry samples are a major determinant of the quality of structural preservation. For cytoskeletons freeze-drying (FD) is superior to critical point-drying (CPD), one reason being that CPD samples have to be dehydrated, thereby causing more shrinkage as compared to FD samples. The high pressures to which samples are exposed during CPD may also cause increased shrinkage, and water contamination during CPD causes severe structural damage. We have obtained the best structural preservation of detergent-extracted and fixed cells by manually plunging them into liquid propane and drying over night in a freeze-drayer.The factor that most limits achievement of high resolution in SEM is the metal coat, which has to be very thin, uniform, and free of grain in order not to hide structures or to create artifactual ones. We have found that sputter-coating with 1-3 nm of tungsten (W) or niobium )Nb( gives extremely fine-grained films as well as satisfactory emission of secondary electrons. These samples can also be examined at high resolution by transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). The best preservation and visualization of supramolecular structures have been obtained using cryosputtering, in which the samples are freeze-dried and then sputter-coated within the freeze-dryer while still frozen. © 1992 Wiley-Liss, Inc.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070220203
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  • 6
    Electronic Resource
    Electronic Resource
    Quantitative morphology for biologists and computer scientists: I. Computer-aided tutorial for biological stereology (version 1.0) (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 21 (1992), S. 338-346 
    Details
    ISSN: 1059-910X
    Keywords: Tutorial ; Electron microscopy ; Light microscopy ; Software ; Quantitative morphology ; Stereology ; Morphometry ; Simulations ; Terminology ; Data types ; Sampling ; Hierarchies ; Interpretation of data ; Bio-Matrix Project ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: This paper describes a computer-aided tutorial for biological stereology. Stereology, a type of quantitative morphology, includes a collection of statistical methods that quantify the structural compartments that can be viewed in sections with light and electron microscopy. These methods provide volume, surface, length, shape, and number data, and help define the quantitative relationships among the structural compartments of biological hierarchies. Hierarchies, which connect structural data ranging in size from molecules to organs, serve as a central core to which the data of biological databases can be linked. The tutorial focuses on two objectives. It provides the user primarily interested in using quantitative morphology databases with background information, and offers a set of state-of-the-art tools to researchers wishing to use these methods in the laboratory. The main topics of the tutorial include: introduction to quantitative morphology, symbols/terms, data types, sampling, hierarchies, data interpretation, and utilities. The tutorial runs under the MS-DOS operating system and requires at least an IBM PC AT (or compatible), a color monitor (EGA, VGA), 540 KB of RAM, and 3 MB of hard disk space. © 1992 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070210409
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  • 7
    Electronic Resource
    Electronic Resource
    Computer assisted data collection for stereology: Rationale and description of point counting stereology (PCS) software (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 21 (1992), S. 347-354 
    Details
    ISSN: 1059-910X
    Keywords: Quantitative morphology ; Morphometry ; Light microscopy ; Electron microscopy ; PCS System III ; MS-DOS ; UNIX ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The paper describes microcomputer software for point counting stereology. Stereology includes a collection of statistical methods that quantify the images of light and transmission electron microscopy. The methods use test grids placed over images to collect raw data, which includes counts of points, intersections, transections, and profiles. In turn, the counts are included in stereological equations that give estimates of compartmental volumes, surfaces, lengths, or numbers. These parameters describe the composition of a structure in three-dimensional space. The PCS (point counting stereology) System Software III serves as a data collection, storage, and management tool. Users set up point counting protocols without programming, enter data by pressing predefined function (MS-DOS) or alphabetic keys (UNIX), store data in files, select files for analysis, and calculate results as stereological densities. The latest version of the PCS software includes a new user interface and is designed as a research “front end” that can feed data either into the calculation tools of a stereology tutorial (Bolender, 1992, this issue) or into the analysis routines of quantitative morphology databases (Bolender and Bluhm, 1992). © 1992 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/jemt.1070210410
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  • 8
    Electronic Resource
    Electronic Resource
    Ultrastructural evidence for the axonal localization of caudodorsal cell hormone mRNA in the central nervous system of the mollusc Lymnaea stagnalis (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 25 (1993), S. 12-18 
    Details
    ISSN: 1059-910X
    Keywords: In situ hybridization ; Digoxigenin ; Electron microscopy ; Cryosections ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The technique of in situ hybridization has been used to evaluate the expression of an ovulation hormone mRNA (caudodorsal cell hormone; CDCH) in the central nervous system (CNS) of the mollusc Lymnaea stagnalis. Hybridization with radioactive as well as with nonradioactive labeled oligonucleotide and plasmid probes revealed a specific labeling on cell bodies of caudodorsal cells (CDCs), which are known to produce CDCH, on the light microscopical level. In addition, specific labeling was observed outside the cell bodies, as far as the cerebral commissure, where CDCH is released in the haemolymph. To investigate whether these signals represent an axonal localization of the CDCH mRNA, we performed in situ hybridization at the electron microscopical (EM) level. The results showed an intraaxonal localization of CDCH mRNA with digoxigenin labeled oligonucleotide and plasmid probes. Gold labeling was observed in secretion granules, and double labeling experiments showed that these granules also contain CDCH. This specific intragranular localization suggest that CDCH mRNA is transported through the axon and released by exocytosis in the haemolymph. © 1993 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070250104
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  • 9
    Electronic Resource
    Electronic Resource
    Protocol of electron microscope in situ nucleic acid hybridization for the exclusive detection of double-stranded DNA sequences in cells containing large amounts of homologous single-stranded DNA and RNA sequences: Application to adenovirus type 5 infected Hela cells (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 25 (1993), S. 2-11 
    Details
    ISSN: 1059-910X
    Keywords: Double-stranded viral DNA ; Electron microscopy ; HeLa cell ; In situ hybridization ; Lytic infection ; S1 nuclease ; Replication ; Viral Ad5 genomes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: In order to gain a further insight into the relationships of the complex process of replication of adenovirus genomes to the substructures which occur in the nuclei of adenovirus type 5 (Ad5) infected HeLa cells, we have visualized directly, at the electron microscopic level, viral double-stranded DNA (dsDNA) in late infected nuclei by the use of a post-embedding in situ hybridization technique with a biotinylated specific DNA probe. The procedure is based on the removal of single-stranded (ss) nucleic acids by S1 nuclease. The highest levels of signal density for viral dsDNA were detected over the fibrils of the large, centrally located viral genome storage site and over the viral nucleoids of both clustered and isolated viruses. Lower but significant signals were observed over the fibrillo-granular network of the peripheral replicative zones, where both transcription and replication of viral DNA occur. On the other hand, the labeling of the enclosed viral ssDNA accumulation sites, also involved in viral replication but not transcription, was negligible, which suggests that, in the latter, the newly synthesized viral dsDNA immediately extends into the adjacent peripheral replicative zone to be transcribed and/or replicated.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070250103
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  • 10
    Electronic Resource
    Electronic Resource
    Quantitative aspects of synapses on Golgi-impregnated neurons (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 23 (1992), S. 334-352 
    Details
    ISSN: 1059-910X
    Keywords: Identified neurons ; Quantification ; Rotating/tilting ; Synaptic contacts ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: With the classical Golgi techniques, numerous types of neurons can be distinguished in the cerebral cortex, each with a specific dendritic geometry and pattern of axonal ramifications. In the present review we describe two techniques which allow quantification of synapses on identified neurons: (1) Golgi-rapid impregnation-gold toning-electron microscopy, and (2) Golgi-Kopsch impregnation-gold toning-electron microscopy in combination with staining of the tissue with ethanolic phosphotungstic acid (E-PTA). Both techniques were applied on neurons in the visual cortex of young and adult rabbits. By means of rotating and tilting specimens in the electron microscope, the nondistinctive ultrastructure of obliquely sectioned synapses can be circumvented, leading to precise estimates of asymmetrical vs. symmetrical synapses without complete reconstruction of the neuron. © 1992 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/jemt.1070230408
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  • 11
    Electronic Resource
    Electronic Resource
    Environmental scanning electron microscope (ESEM) evaluation of crystal and plaque formation associated with biocorrosion (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 25 (1993), S. 429-433 
    Details
    ISSN: 1059-910X
    Keywords: Biocorrosion ; Sulfate-reducing bacteria ; Biofilm ; Desulfovibrio ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The biofilm attributed to Desulfovibrio vulgaris growing in the presence of ferrous metals was examined with an environmental scanning electron microscope. This novel microscope produced images of iron sulfide colloids and other iron containing structures that had not been reported previously. A plaque composed of iron sulfide enveloped the surface of the corroding metal while crystals containing magnesium, iron, sulfur, and phosphorus were present in the culture where corrosion was in progress. A structure resembling the tubercule found in aerobic corrosion was observed on stainless steel undergoing biocorrosion and the elements present in this structure included sulfur, iron, chloride, calcium, potassium, and chromium. © 1993 Wiley-Liss, Inc.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/jemt.1070250513
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  • 12
    Electronic Resource
    Electronic Resource
    Rapid primary microwave-glutaraldehyde fixation preserves the plasma membrane and intracellular structures of the protozoan Tritrichomonas foetus (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 25 (1993), S. 286-290 
    Details
    ISSN: 1059-910X
    Keywords: Microwave fixation ; Freeze-fracture ; Electron microscopy ; Protozoan ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Tritrichomonas foetus, a pathogenic protozoan, was used as a model to analyse microwave-stimulated fixation as a procedure of preparation of biological samples for electron microscopy of thin sections and freeze-fracture replicas. Good preservation of the protozoan structure was achieved by microwave-stimulated fixation and Epon polymerization. The membrane structure, as visualized in freeze-fracture replicas, was well preserved. © 1993 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/jemt.1070250404
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  • 13
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    Peripheral sensilla of some lower invertebrates: The platyhelminthes and nematoda (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992), S. 285-297 
    Details
    ISSN: 1059-910X
    Keywords: Electron microscopy ; Evolution ; Flatworms ; Nematodes ; Nervous system ; Review ; Sense organs ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The flatworms (Platyhelminthes) and the round worms (Nematoda) are phylexhibiting strikingly different levels of cellular organization. In both, sensilla are composed of the endings of sensory dendrites intercalated into their epidermis.In flatworms, sensilla that penetrate the syncytial epidermis bear sensory processes derived from cilia. In free-living species, the sensory processes more closely resemble motile cilia, while in parasites, greater deviations occur from the classical cilium pattern. Estimates of the function of the various sensilla have been largely arbitrary, and remain based on ultrastructural features.Sensilla in round worms lie below or within a heavy secreted cuticle. Two glia-like cell types occur. The socket cell mediates contact with cuticle and is responsible for cuticular modifications essential for operation of the sensillum. The sheath cell forms a receptor cavity around the sensory processes and regulates its environment. Sensory processes vary greatly from the classical cilium pattern. Absence of a basal body, but preservation of a ciliary necklace, suggests that the latter has a primary importance in sensory transduction. Estimates of function are based largely on ultrastructural features and analogies to arthropod sensilla. Genetic studies with the free-living nematode Caenorhabditis are beginning to demonstrate details of function and development.Speculations on the roles of basal bodies, rootlets, and vesicles and on the significance of recessed sensilla are given. © 1992 Wiley-Liss, Inc.
    Additional Material: 26 Ill.
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    URL: http://dx.doi.org/10.1002/jemt.1070220306
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  • 14
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    Phylogeny of the vomeronasal system and of receptor cell types in the olfactory and vomeronasal epithelia of vertebrates (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 23 (1992), S. 1-21 
    Details
    ISSN: 1059-910X
    Keywords: Cilia ; Microvilli ; Ultrastructure ; Electron microscopy ; Evolution ; Cladistics ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: In this paper, the evolutionary origin of the vomeronasal system as a discrete sensory system separate from olfaction is examined. The presence of a discrete vomeronasal system appears to be a derived character in tetrapods, and its presence in larval amphibians indicates that the system did not arise as a terrestrial adaptation. The vomeronasal system has been lost independently in several taxa, including crocodilians, some bats, cetaceans, and some primates. The presence of microvillar receptor cells in the vomeronasal epithelium appears to be the ancestral condition for tetrapods, and alternative hypotheses concerning the ancestral condition for receptor cell types in the vertebrate olfactory epithelium are discussed. Finally, the possibility that the vomeronasal system is present in some fishes in a form that has not been recognized is discussed in relation to the phylogenetic distribution of receptor cell types in vertebrates. © 1992 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/jemt.1070230102
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  • 15
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    Fine structure of olfactory epithelia of gastropod molluscs (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992), S. 307-324 
    Details
    ISSN: 1059-910X
    Keywords: Sensory ; Chemosensory ; Ultrastructure ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Among gastropod molluscs the chemical senses are most important for location of distant objects. They are used in food finding, locating mates, avoiding predators, trail following, and homing. Chemoreceptors are commonly associated with the oral area, the tentacles, and the osphradium, which lies in the mantle cavity.Most chemosensory neurons are primary sensory neurons, although secondary sensory cells have been reported in the osphradium of some prosobranch gastropods. Most chemosensory organs contain sensory cells with ciliated sensory endings that are in contact with the external environment. Some sensory endings have only microvilli or have no surface elaborations. Cilia on sensory endings are commonly of the conventional type, but some species have modified cilia; some lack rootlets, some have an abnormal microtubular content, and some have paddle-shaped endings. The perikarya of sensory neurons may be within the sensory epithelium, below it, or in ganglia near the sensory surface. In some groups of gastropods there are peripheral ganglia in the olfactory pathway; in others chemosensory axons appear to pass directly to the CNS.Olfactory epithelia of terrestrial pulmonates have modified brush borders with long branching plasmatic processes and a spongy layer of cytoplasmic tubules which extend from the epithelial cells. Sensory endings of the olfactory receptors are entirely within this spongy layer. Aquatic pulmonates may have a similar spongy layer in their olfactory epithelia, but the cilia of sensory endings, as well as motile cilia of epithelial cells, extend well beyond the spongy layer. © 1992 Wiley-Liss, Inc.
    Additional Material: 36 Ill.
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    URL: http://dx.doi.org/10.1002/jemt.1070220402
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  • 16
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    The aesthetasc concept: Structural variations of putative olfactory receptor cell complexes in crustacea (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992), S. 325-335 
    Details
    ISSN: 1059-910X
    Keywords: Sensilla ; Electron microscopy ; Sexual dimorphism ; Homology ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The structure of the aesthetascs has been investigated in the prawn Macrobrachium rosenbergii (larvae and juveniles), the opossum shrimp Neomysis integer, the euphausid Meganyctiphanes, and in the water-fleas Daphnia magna and D. longispina. The aesthetascs, that are thought to represent olfactory receptors, exhibit a considerable structural variation, ranging from the well known aesthetascs of higher crustaceans (lobster, crab, crayfish) to the corresponding sensilla found in the water-fleas and the males of opossum shrimps. The two following morphological characteristics of the aesthetascs are thought to indicate an olfactory function: the shape of the cuticular hair that is long and essentially hose-shaped, and the thin, loosely arranged cuticle of at least the outer part of the cuticular hair. The presence of other structural elements such as sensory cells, cilia, and enveloping cells are vital for the olfactory function, but the development is variable, which makes their use in the morphological definition of aesthetascs problematic. © 1992 Wiley-Liss, Inc.
    Additional Material: 20 Ill.
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    URL: http://dx.doi.org/10.1002/jemt.1070220403
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  • 17
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    Fine structure of olfactory sensilla in myriapods and arachnids (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 22 (1992), S. 372-391 
    Details
    ISSN: 1059-910X
    Keywords: Olfactory chemoreceptors ; Electron microscopy ; Wall structures ; Sheath cells ; Dendrites ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Structural features of various types of olfactory sensilla are reviewed. (1). Sensilla basiconica which differ in form and size are found on the antennae of centipedes and millipedes. Their walls show longitudinal slits or grooves that either open into the sensillum lumen or do not penetrate the cuticle. In other such sensilla the outer surface is pierced by pores and the inner surface grooved and pocketed. These sensilla are innervated by one to six sensory cells. Their unbranched outer dendritic segments extend to the tip of the sensillum. The sensory cells are surrounded by two or three sheath cells which terminate at the sensillum base or form a continuous tube around the entire length of the outer dendritic segments. (2) Temporal organs of centipides are located between the insertion of the antenna and the ocelli. These sensilla consist of a shallow cuticular ring with a central sensory plate made up by a layer of unperforated cuticle or a capsule with a mushroom-shaped structure inside formed by fibrous-looking cuticle. A dozen sensory cells with unbranched outer dendritic segments innervate each sensillum. They extend toward the sensory cuticle and pass just below it. Numerous sheath cell processes run parallel to the outer dendritic segments up to the sensory cuticle. (3) Thread-like flagella of Pauropoda are found on the antennae. They possess a flexible unperforated cuticular wall. These sensilla contain nine sensory cells surrounded by several sheath cells which form a continuous cytoplasmic tube around the outer dendritic segments. (4) Single-walled sensilla with numerous plugged pores penetrating the cuticular wall occur on the tarsus of the first leg in ticks. Each sensillum is innervated by 4-15 sensory cells. Three sheath cells terminate in the base of the sensillum. (5) Double-walled sensilla with spoke canals are found on the first tarsus of ticks. Their shaft is longitudinally grooved. Pore canals lead inward from the bottom of the grooves and open into vase-shaped chambers. From its base these canals extend into the lumen of the sensillum which contains unbranched outer dendritic segments of 1-2 sensory cells. (6) Single-walled sensilla with pore openings occur on the distal tarsal segments of the first leg of whip spiders. These sensilla are innervated by 40-45 sensory cells. Their unbranched outer dendritic segments fill the shaft lumen and extend partly into the wall pores. Microvillus-shaped sheath cell processes line the inner surface of the cuticular wall. (7) Tarsal organs are located dorsally on the tarsus of all legs and pedipalps of spiders. These sensory organs consist of a cuticular capsule with a dome-shaped projection inside. It is situated on the proximal sidewall of the capsule and possesses 7 pore canals that enclose the dendritic tips of 2-3 sensory cells, giving a total of 20 sensory cells. Each group of dendrites terminating in an individual pore canal is encased by 2 sheath cells. © 1992 Wiley-Liss, Inc.
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    Characterization of the suprachiasmatic nucleus in organotypic slice explant cultures (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 25 (1993), S. 46-60 
    Details
    ISSN: 1059-910X
    Keywords: Vasopressin ; Vasoactive intestinal polypeptide ; Gastrin releasing peptide ; GABA ; In vitro ; In situ hybridization histochemistry ; Electron microscopy ; Circadian pacemaker ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Suprachiasmatic nuclei (SCN) from hypothalami of postnatal rats were maintained for 18-39 days in vitro as organotypic slice explants. Neuronal subtypes containing vasopressin (VP), vasoactive intestinal polypeptide (VIP), gastrin releasing hormone (GRP), and GABA were immunocytochemically identifiable in these cultures. In situ hybridization histochemistry was compatible with these SCN slice explant cultures, and mRNA encoding for VP was detected bilaterally within these nuclei. After 18 days in vitro, both VP mRNA and VP immunoreactivity increased from levels present on postnatal days 4 (the earliest age from which the explanted tissue was derived) to levels typical of adult SCNs. In contrast, the GRP expression remained low, characteristic of early postnatal animals and far lower than adult levels. This suggests that the developmental cues or programs necessary for enhanced VP expression are maintained in these cultures, while those affecting GRP expression are absent or inhibited. VIP-containing neurons were numerous in the cultures. Culture slices appeared healthy, and similar numbers and distributions of identifiable neurons within the SCN were observed, whether or not the slices were grown in the presence of serum. EM analysis revealed that the SCN in vitro is composed of tightly packed neurons, processes, and abundant synapses containing both clear and dense core vesicles, closely resembling the SCN in vivo. Vasopressinergic neuronal somata contained extensive Golgi systems and labeled secretory granules, the latter organelle being present also within processes and synaptic terminals. GABA-immunopositive processes and synaptic profiles were abundant, with labeling occurring particularly over secretory vesicles and mitochondria. This slice culture system effectively maintained much of the intrinsic organization and cellular components of the SCN for long periods in vitro and should be an excellent model system for studying the intrinsic molecular mechanisms and extrinsic cues which regulate neuronal phenotype in this circadian pacemaker. Published 1993 Wiley-Liss, Inc.
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    Simulation of dislocations imaged moiré fringe contrast (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 24 (1993), S. 185-192 
    Details
    ISSN: 1059-910X
    Keywords: Electron microscopy ; Epitaxy ; Dislocations ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Transemission electron microscope (TEM) images of dislocations as produced via moiré fringe contrast are simulated using many-beam diffraction theory. The effect of edge dislocations on both parallel and rotational moiré fringe patterns is considered. For the parallel moiré fringe pattern, images of dislocations both perpendicular to the film plane and those inclined to the film plane are produced. The effect of an inclined dislocation is shown to cause a distortion of the dislocation image. Finally, a comparison between predicted and experimentally observed images is made, with the results indicating that threating dislocations in the FeAl/GaAs system have line directions nearly perpendicular to the (001)FeAl/GaAs film plane. © 1993 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jemt.1070240211
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    Age-Related changes in cartilage proteoglycans: Quantitative electron microscopic studies (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 28 (1994), S. 398-408 
    Details
    ISSN: 1059-910X
    Keywords: Aging ; Proteoglycans ; Electron microscopy ; Intervertebral disc ; Hyaline cartilage ; Nucleus pulposus ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Biochemical and biophysical studies have shown that the composition and sedimentation velocity of cartilage proteoglycans change with age, but these investigations cannot demonstrate the alterations in molecular structure responsible for these changes. Development of quantitative electron microscopic methods has made it possible to define the age-related structural changes in aggregating proteoglycans and to correlate the alterations in their structure with changes in tissue composition and morphology. Electron microscopic measurement of human and animal hyaline cartilage proteoglycans has shown that with increasing age the length of the chondroitin sulfate-rich region of aggregating proteoglycan monomers (aggrecan molecules) decreases, the variability in aggrecan length increases, the density of aggrecan keratan sulfate chains increases, the number of monomers per aggregate decreases, and the proportion of monomers that aggregate declines. Proteoglycans from the nucleus pulposus of the intervertebral disc show similar but more dramatic age-related alterations. At birth, nucleus pulposus aggrecan molecules are smaller and more variable in length than those found in articular cartilage. Within the first year of human life, the populations of aggregates and large aggrecan molecules analogous to those found in articular cartilage decline until few if any of these molecules remain in the central disc tissues of skeletally mature individuals. The mechanisms of the age-related changes in cartilage proteoglycans have not been fully explained, but measurement of proteoglycans synthesized by chondrocytes of different ages suggests that alterations in synthesis produce at least some of the age-related changes in aggrecan molecules. Degradation of aggrecan chondroitin sulfate-rich regions in the matrix probably also contributes to the structural changes seen by electron microscopy. Age-related changes in proteoglycan aggregation may be due to alterations in link protein function or inhibition of aggregation of newly synthesized aggrecan molecules by accumulation of degraded aggrecan molecules. © 1994 Wiley-Liss, Inc.
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    Calculation of overall tilt angles for a double tilt holder in a TEM (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 28 (1994), S. 448-451 
    Details
    ISSN: 1059-910X
    Keywords: Angular relationship ; Tilting ; Electron microscopy ; Goniometer ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A simple formula has been derived for the tilt angle of a specimen in terms of the two tilt angles of a side entry, double tilt holder in a transmission electron microscope. An expression for calculating the direction of the apparent tilt axis in relation to the observed diffraction pattern has also been derived. The accuracy and reproducibility of specimen tilting has been assessed experimentally. © 1994 Wiley-Liss, Inc.
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    Adenosine 5′-triphosphate promotes mineralization in differentiating chick limb-bud mesenchymal cell cultures (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 28 (1994), S. 492-504 
    Details
    ISSN: 1059-910X
    Keywords: Calcification ; Hydroxyapatite ; Matrix synthesis ; FT-IR microscopy ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: When chick limb-bud mesenchymal cells are plated in micromass culture, they differentiate to form a mineralizable cartilage matrix. Previous studies have demonstrated that, when the total inorganic phosphate concentration of the medium is adjusted to 3-4 mM by adding inorganic phosphate to the basal medium, the mineralized matrix formed resembles that of chick calcified cartilage in ovo. When the high-energy phosphates adenosine 5′-triphosphate (ATP) or creatine phosphate are used as supplements in place of inorganic phosphate, the mineralized matrix as analyzed by electron microscopy and Fourier transform infrared microscopy is also similar to that in ovo. This is in marked contrast to the mineralized matrix formed in the presence of 2.5-5 mM β-glycerophosphate, where mineral deposition is random and mineral crystal sizes in general are larger. This is also in contrast to the known ability of ATP to inhibit mineral deposition in solution in the absence of cells.In the differentiating mesenchymal cell culture system, ATP does not alter the rate of cell proliferation (DNA content), the rate of matrix synthesis (3H-leucine uptake), the mean crystallite length, or the rate of mineral deposition (45Ca uptake) when contrasted with cultures supplemented with inorganic phosphate. However, ATP does increase the mineral to matrix ratio, especially around the edge of the culture, where a type I collagen matrix is present. It is suggested that ATP promotes mineral deposition by providing a high-energy phosphate source, which may be used to phosphorylate extracellular matrix proteins and to regulate calcium flux through cell membranes. © 1994 Wiley-Liss, Inc.
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    Improved ultrastructural preservation of rat ciliary body after high pressure freezing and freeze substitution: A perspective view based upon comparison with tissue processed according to a conventional protocol or by osmium tetroxide/microwave fixation (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 29 (1994), S. 11-22 
    Details
    ISSN: 1059-910X
    Keywords: Cryofixation ; Electron microscopy ; Extracellular material ; Microtubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Conventional fixation of the delicate, highly folded rat ciliary body and its iridial extension, as well as of vitreal structures, is associated with the induction of a number of artifacts, thus limiting the reliability of morphological interpretations. Improved ultrastructural preservation may be achieved by microwave heating in combination with osmium tetroxide fixation. This protocol, although simple and cheap, yields results, particularly with respect to the extracellular matrix compartment between inner and outer ciliary epithelial cells, which are not greatly inferior to those obtained by implementing the sophisticated high pressure freezing and freeze substitution technique. The latter affords good to very good ultrastructural preservation of epithelium and stromal components, such as blood vessels, neural elements, smooth muscle cells, fibrocytes, and free cells, up to a depth of 50-100 μm from the tissue surface. Its superiority over osmium tetroxide/microwave fixation is revealed in the cytoplasmic, intraorganellar, and vitreal matrix compartments, which incur no obvious losses. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jemt.1070290103
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    Fine structure of Tritrichomonas foetus as seen using cryotechniques (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 29 (1994), S. 37-46 
    Details
    ISSN: 1059-910X
    Keywords: Tritrichomonas foetus ; Freeze-fracture ; Electron microscopy ; Fast-freezing fixation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Tritrichomonas foetus was studied using different physical and chemical fixation methods such as fast-freezing (by high pressure, “slam-freezing,” and jet-propane), freeze-substitution, conventional freeze-fracture and deep-etching, cryoultramicrotomy, and routine preparation for transmission electron microscopy. The use of fast-freezing fixation (FFF) proved to be superior in terms of structural preservation due to the rapidity of this fixation compared to that obtained using conventional chemical fixation. The low temperature techniques used here were useful to confirm data already obtained by conventional freeze-fracture using chemical fixation and cryoprotection, such as the presence of flagellar rosettes and costa structure. Cryoultramicrotomy and slam-freezing also demonstrated the presence of hair-like structures projecting out from the protozoan surface. New aspects of organelles of T. foetus were demonstrated. Published 1994 by Wiley-Liss, Inc.
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    Liquid crystalline order of biopolymers in cuticles and bones (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 27 (1994), S. 420-428 
    Details
    ISSN: 1059-910X
    Keywords: Self-assemblies ; Chitin ; Collagen ; Polarizing microscopy ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Microscopic studies at different scales have shown that in biological tissues the three-dimensional arrangement of chitin-protein or of collagen fibrillar networks can follow the same spatial distributions as those described in certain liquid crystals. The present work reviews the structural analogies established between the dense fibrillar organic matrix found in two materials: crab cuticles and compact bones. In both systems mobile fringes are described in polarizing microscopy, periodic cleavage aspects in scanning electron microscopy (SEM), and arced patterns in transmission electron microscopy (TEM). In parallel to these structural data, results obtained in vitro are recalled which corroborate the relationship established between ordered arrays of biopolymers and liquid crystalline assembly principles, highly concentrated solutions of purified collagen molecules spontaneously form ordered assemblies characterized in polarizing microscopy as cholesteric phases. This particular state of matter joins both fluidity and order and could correspond to a transient state of collagen or chitin secretion, before the stiffening of these skeletal structures, bone or cuticle, by molecular cross-links and crystalline deposition. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jemt.1070270508
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    Ultrastructural diagnosis of human pituitary adenomas (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 20 (1992), S. 107-135 
    Details
    ISSN: 1059-910X
    Keywords: Electron microscopy ; Endocrine neoplasm ; Pituitary adenomas ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Electron microscopy, which has been instrumental in the characterization of normal pituitary cell types, has also played a crucial role in the mirphologic classification pituitary adenomas arising in the presently known 5 cell types, and in the recognition of 3 adenoma types with yet undisclosed cell derivation. This review deals with the application of electron microscopy for study of pituitary adenomas in order to provide specific pathological diagnosis and aid the clinician in selecting appropriate postoperative treatment. In addition to the ultrastructural appearance and diagnostic features of 15 adenoma types, the morphology of hyperplastic proliferations and that of known normal counterparts of various adenoma types are also discussed. Specific morphologic diagnosis of pituitary lesions is important not only for adequate postoperative management of patient, but is also a prerequisite for study of the natural history and biological behaviour of various adenoma types.
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    URL: http://dx.doi.org/10.1002/jemt.1070200202
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    The ultrstructure of neuronal-pinealocytic interconnections in the monkey pineal (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 21 (1992), S. 124-135 
    Details
    ISSN: 1059-910X
    Keywords: Pinealocyte ; Pineal-neuron ; Synapses ; Ribbon synapse ; Innervation ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Recent ultrastructural studies of neuronal-pinealocytic interconnections in the monkey pineal are reviewed. The pinealocytes in the adult monkey show almost all of the cytological specializations known in subprimate mammals. Adjacent pinealocytes are functionally coupled through ribbon synapses on cell bodies and gap junctions on cell bodies and cell processes. The pinealocytes receive direct synaptic contacts of nerve fibers with cholinergic terminal morphology. Nerve cells restricted to the central portion of the pineal receive synaptic contacts with more than three different morphologically defined types of nerve terminals. In addition to nerve terminals containing small clear vesicles or vesicles of pleomorphic morphology, a pinealocyte's terminal process containing the synaptic ribbon forms a true synaptic contact on the nerve cell body. The diversity of synapses on these nerve cells strongly suggests multiple origins of these neurons rather than a single peripheral parasympathetic origin. The possible involvement of pineal neurons in an intrinsic circuit that regulates the function of pinealocytes and integrates the neural input from the central as well as the peripheral nervous systems is discussed.
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    URL: http://dx.doi.org/10.1002/jemt.1070210205
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    Fine structure of the vomeronasal and septal olfactory epithelia and of glandular structures (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 23 (1992), S. 86-97 
    Details
    ISSN: 1059-910X
    Keywords: Accessory olfactory ; Nasal glands ; Odorant binding protein ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The vomeronasal and septal olfactory organs are two neurosensory structures in the mammalian nasal septum which are poorly understood relative to the main olfactory system. The vomeronasal organ is a paired, blind-ending tubular structure that opens rostrally into the nasal cavity in some species and into the incisive ducts in others. When present in mammals, the septal olfactory organ is an island of olfactory mucosa positioned such that it is in the primary air pathway in the caudal portion of the nasal cavity. Mammalian nasal glands, with a diverse histochemical and ultrastructural morphology, secrete a variety of substances onto the mucosal surface. One of these substances, odorant binding protein, localized in bovine nasal glands and lateral nasal glands of rodents may be important in the capture and conveyance of odorant molecules to olfactory receptors. The objectives of this paper are to present original data while reviewing the literature on the ultrastructure of vomeronasal and septal olfactory neuroepithelia, and of vomeronasal, bovine nasal, and lateral nasal glands. Nasal tissues from pigs, calves, and hamsters were prepared for electron microscopy. Neurosensory epithelia of the porcine vomeronasal organ and the hamster septal olfactory organ are similar to that described for the vomeronasal and septal olfactory organs of other mammals. Bovine nasal and rodent lateral nasal glands consist of subregions which differ morphologically; the most abundant acinar cell type in the bovine nasal gland contains lightly electron dense secretory granules while that of the rodent lateral nasal gland contains both small electron dense and large, electron lucent granules. The porcine vomeronasal gland contains numerous small, dense granules of a diverse morphology. © 1992 Wiley-Liss, Inc.
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    Morphological study of the effects of intranasal zinc sulfate irrigation on the mouse olfactory epithelium and olfactory bulb (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 24 (1993), S. 195-213 
    Details
    ISSN: 1059-910X
    Keywords: Deafferentation ; Regeneration ; Sensory afferents ; Electron microscopy ; Olfactory receptor cells ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The effects of intranasal zinc sulfate (ZnSO4) irrigation on the morphology of the olfactory epithelium and olfactory bulb were studied in mice with short survival times (as early as 1 day) and with long survival times (up to 593 days) after the irrigation procedure. As in several previous studies, the olfactory epithelium was completely destroyed within a few days after the ZnSO4 treatment. Within 2-4 days, the septum and turbinates were covered by a new, cuboidal epithelium, the cells of which differed significantly from any cells normally seen in the olfactory epithelium. Slowly, over several months, small areas of the olfactory epithelium regenerated in many of the animals.The ultrastructural changes occurring in the olfactory bulb from 1 to 25 days (the reactive stage) were characterized by degenerating olfactory axons and axon terminals, hypertrophy of astroglial cell processes, and proliferation of or extravasation by phagocytic cells. By 25 days after intranasal ZnSO4 irrigation, the number of reactive glial processes and phagocytic cells returned to normal. In some mice with survival times of 150 days or longer, there was reinnervation of small areas of the olfactory bulb by regenerated olfactory axons. These new olfactory axons innervated only superficial glomeruli or the outer portions of deeper glomeruli, but they formed synaptic contacts with mitral/tufted cells and periglomerular cells that did not differ from control animals. These findings were supported by tract-tracing experiments with 3H-amino acids and by behavioral analysis.In summary, the ultrastructural changes observed in the olfactory bulb in this study were not significantly different from those observed after surgical lesions of the olfactory epithelium or nerve. The olfactory bulb, however, never fully recovered; glomeruli remained shrunken (though with normal dendro-dendritic synaptic connections), and there was minimal olfactory axon reinnervation. © 1993 Wiley-Liss, Inc.
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    Dynamics of golgi impregnation in neurons (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 23 (1992), S. 264-274 
    Details
    ISSN: 1059-910X
    Keywords: CNS ; Light microscopy ; Electron microscopy ; Cerebral cortex ; Nerve cell ; Impregnation method ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: This paper describes the early stages of impregnation by the Golgi rapid method in sections and blocks of brain tissue. Aldehyde-fixed and potassium dichromate-treated sections of cerebral cortex were placed on glass slides and coverslipped. The dichromate solution was then replaced by a silver nitrate solution, and events taking place in the section were monitored and time-lapse recorded until the impregnation was interrupted and the sections subsequently prepared for electron microscopy. The tissue blocks, fixed and chromated in the same way, were placed into a silver nitrate solution for 30 min to 24 h and the progress of impregnation compared with the results obtained in the sections on the glass slides.Two basic modes of impregnation were observed, apparently in direct relation to the process of crystallization of silver chromate: crystals of silver chromate growing directly from the surface of the tissue into the nerve cell via its transected plasma membranes, and microcrystalline precipitate of silver chromate spreading into the nerve cell from nucleation centres dispersed in the tissue. The precipitate grows inside the cell as in a preformed channel until the cell has been filled. If the nucleation begins extracellularly, the precipitate extends into the narrow intercellular gaps. Electron microscopy showed that the crystalline precipitate consisted of multilamellar formations containing dense coalesced granules that did not cross plasma or endocellular membrane boundaries. © 1992 Wiley-Liss, Inc.
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    Morphological effects of diabetes on the granular ducts and acini of the rat submandibular gland (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 27 (1994), S. 61-70 
    Details
    ISSN: 1059-910X
    Keywords: Salivary gland ; Diabetes ; Insulin ; Electron microscopy ; Streptozotocin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Effects of experimental diabetes on rat submandibular glands have been documented, but earlier reports suggested that diabetes caused an extensive cellular degeneration and a replacement of the parenchymal cells by fibrous connective tissue. Such observations, however, are difficult to reconcile with the relatively normal physiological responsiveness of the gland (Anderson and Suleiman, 1989). This study, therefore, reexamined the histological, histochemical and ultrastructural effects of streptozotocin-induced diabetes on rat submandibular glands. The tissues were examined at 3 weeks, and 3 and 6 months after the induction of diabetes, and compared with glands from age-matched controls by both light and electron microscopy. Light microscopically, the proportional volumes of the acini and granular ducts remained constant in control rats at about 48% and 38% respectively. In diabetic animals the volume density of the acini increased progressively to 62%, whereas that of the granular ducts decreased to 20%. The diameter and number of granular ducts were reduced in diabetic animals, but acinar cell profile area was only affected 6 months after the induction of diabetes. Ultrastructurally, there was an accumulation of lipid in the acinar cells and, with increasing duration of diabetes, the number of autophagic structures in both the acini and the granular ducts increased. Although there was evidence of some cellular degeneration it was never excessive. Morphometry showed that the volume density of secretory granules within the acinar cells was unaffected, but there was a significant reduction in the volume density of secretory granules within the granular ducts. Thus, in the rat submandibular gland the greatest effect of streptozotocin-induced diabetes was to cause hypotrophic changes in the cells of the granular ducts. The relative contributions of a direct effect of insulin insufficiency and the hypogonadal effects of diabetes, however, are not known. © 1994 Wiley-Liss, Inc.
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    Immunogold labelling of leukemic hairy cells with the B-ly7 monoclonal antibody: An SEM and TEM study (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 28 (1994), S. 356-367 
    Details
    ISSN: 1059-910X
    Keywords: Hairy cell leukemia ; Immunogold labelling ; B-ly7 antibody ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Two cases of hairy cell leukemia have been studied by immuno-TEM and immuno-SEM after immunogold labelling of the cell surface antigen recognized by the B-ly7 monoclonal antibody.Most hairy cells appeared significantly labeled, although the density of the expression of the antigen, as demonstrated by immunogold labelling, seems variable from cell to cell. Moreover, some cells with the morphology of hairy cells and which could not be identified as monocytes were not labeled. Labelling for the antigen identified by the B-ly7 mAb does not seem to correlate with the presence of ribosome lamellae complexes which were present only in one of the two cases studied. Rare lymphocytes of unidentified lineage were labeled. Monocytes were significantly absent from the samples of peripheral blood of the two patients studied. In one normal control sample, monocytes were observed unlabelled.The results are discussed in reference to the pathogenesis of hairy cell leukemia, its surprisingly low mitotic rate, and its distinct response to chemotherapy. © 1994 Wiley-Liss, Inc.
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    Comparison of nuclear hydration in boar spermatozoa before and after freeze-thawing: Contrast analysis of cells embedded in bromide-labeled medium (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 21 (1992), S. 249-254 
    Details
    ISSN: 1059-910X
    Keywords: Electron microscopy ; Water ; Image analysis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Epon labeled with bromide was used to embed ejaculated and freeze-thawed spermatozoa, with the hypothesis that it replaces most of cell water. Image analysis of relative contrasts between sperm nuclei and the surrounding medium revealed that when used in low concentrations, bromide is mostly absorbed to the nuclear structures. For higher concentrations, the chromatin is saturated, and the increase in contrast can be used to calculate relative differences in the hydration of nuclei. Boar sperm nuclei are more hydrated after freeze-thawing than before. © 1992 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jemt.1070210308
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    Synaptic organization and development of the antennal lobe in insects (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 24 (1993), S. 260-280 
    Details
    ISSN: 1059-910X
    Keywords: Neuroanatomy ; Invertebrate brain ; Neurons ; Glial cells ; Olfactory system ; Immunocytochemistry ; Electron microscopy ; Neural development ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Many insects possess a highly developed sense of smell. This paper summarizes the cellular and synaptic organization of the antennal (olfactory) lobe of the insect brain and then reviews morphological and fine-structural aspects of the development of the lobe. Visualization of synapses between classes of neurons identified by physiological, morphological, or transmitter-cytochemical properties has provided insights into arrangements of contacts and their possible roles in information processing. Studies of development have revealed the requirement for afferent axons from the antenna for the formation of olfactory glomeruli, where virtually all of the synapses in the lobe occur, and have suggested the possibility that glial cells play a role in the instructive influence of the axons on their target neurons in the lobe. The findings reviewed in this paper are primarily from one representative hemimetabolous insect, the American cockroach, and one representative holometabolous insect, a hawkmoth, and comparisons are made with vertebrate systems when appropriate. © 1993 Wiley-Liss, Inc.
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    Computer-assisted morphometry: Point, intersection, and profile counting and three-dimensional reconstruction (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 21 (1992), S. 262-270 
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    ISSN: 1059-910X
    Keywords: Stereology ; Software ; Coordinate geometry ; Volume density, Surface density ; Numerical density ; Serial sections ; Light microscopy ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The use of computers in morphometry can involve (1) automated image analysis, semiautomated image analysis and point, intersection, intercept and profile counts of two-dimensional images on tissue sections with mathematical extrapolation to the third dimension, (2) direct measurement of volumes, surfaces, lengths, and curvature using x,y,z coordinates of serial sectioned images, or (3) stereologic techniques and serial sections which is a combination of 1 and 2 above. Automated and semiautomated image analysis are generally restricted to specimens that are characterized by differential contrast such as interalveolar septa in the lung or histochemically stained mucous granules in pulmonary epithelium. Point, intersection, and profile counts using hand-held, notebook PCs, portable PCs, or standard PCs and MS-DOS - based application programs are extremely efficient, precise, affordable, and convenient methods of quantitating average values of a population. When morphometric measurements of individual structures are required, computer-assisted three-dimensional reconstruction using x,y,z coordinates of the surface outline from serial sections is a tedious yet precise method. We describe a computer program that efficiently estimates mean caliper diameter, volume, and surface area with less than five percent error with five sections per structure. We also describe a program that does digital image subtraction on serial sections, superimposes digitally generated test systems on biological images, and accumulates point, intersection, and profile counts using a Macintosh II series computer. © 1992 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jemt.1070210403
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    Ultrastructural and functional connectivity of intracellularly stained neurones in the vertebrate retina: Correlative analyses (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 24 (1993), S. 43-66 
    Details
    ISSN: 1059-910X
    Keywords: Retina ; Intracellular staining ; Horseradish peroxidase ; Electron microscopy ; Cone ; Horizontal cell ; Bipolar cell ; Amacrine cell ; Ganglion cell ; Neurotransmitter ; Synaptic plasticity ; Spinules ; Rhodamine ; Double labelling ; Postembedding immunohistochemistry ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A variety of intracellular recording and staining techniques has been used to establish structure-function and, in some cases, structure-function-neurochemical correlations in fish, turtle, and cat retinae. Cone photoreceptor-horizontal cell connectivity has been studied extensively in the cyprinid fish retina by intracellular staining with horseradish peroxidase (HRP) and subsequent electron microscopy. The available data suggest that horizontal cell dendrites around the ridge of the synaptic ribbon are postsynaptic, whilst finger-like extensions (“spinules”) of lateral dendrites function as inhibitory feedback terminals. An interesting feature of this inter-action is its plasticity: the feedback pathway is suppressed in the dark and becomes potentiated by light adaptation of the retina.Intracellular recordings and stainings of ganglion cells in both turtle and cat retinae have been possible. Prelabelling of ganglion cells by retrograde transport of rhodamine from the tectum allows ganglion cells to be stained under visual control, and their synaptic inputs determined by electron microscopy. Such studies have been extended to double labelling by using autoradiography or postembedding immunohistochemistry to identify the neurotransmitter content of the labelled cell and/or the neurotransmitter(s) converging upon it. It is envisaged that further applications of intracellular staining followed by double- or even triple-labelling will continue to enhance greatly our understanding of the functional architecture of the vertebrate retina. © 1993 Wiley-Liss, Inc.
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    Quantitative analysis of the porous structure of a petroleum reservoir (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 25 (1993), S. 173-174 
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    ISSN: 1059-910X
    Keywords: Porosity ; Mathematical Morphology ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
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    URL: http://dx.doi.org/10.1002/jemt.1070250210
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    Biosynthetic routing of pulmonary surfactant proteins in alveolar type II cells (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 26 (1993), S. 366-373 
    Details
    ISSN: 1059-910X
    Keywords: Immunogold labeling ; Electron microscopy ; Lung ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Surfactant proteins A, B, and C (SP-A, SP-B, and SP-C) are synthesized in alveolar type II cells. SP-B and SP-C are both synthesized as large precursor molecules that are proteolytically processed to their mature sizes. In a previous immunoelectron microscopic study, we showed that precursor SP-B is processed to its mature size in multivesicular bodies. In the present study, using a specific antibody aginst precursor SP-C, we demonstrate that precursor SP-C is present in the same intracellular compartments of the biosynthetic pathway, i.e., endoplasmic reticulum, Golgi complex, and multivesicular bodies, as precursor SP-B. Since mature SP-C is known to be present in multilamellar bodies, this suggests a biosynthetic routing and site of processing of this protein similar to those of SP-B. Double-labeling experiments using antibodies against SP-A, precursor SP-B, precursor SP-C, and an antibody against HA I, an adaptor protein involved in the budding of transport vesicles from the Golgi complex, showed that the different surfactant proteins traverse and exit the Golgi complex via the same route. The surfactant proteins do not exit the Golgi complex via HA I-positive coated buds or vesicles. These data are in accordance with the concept that SP-A, SP-B, and SP-C are transported together through the same biosynthetic pathway via multivesicular bodies to multilamellar bodies. © 1993 Wiley-Liss, Inc.
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    Pathology of the salivary glands: The contribution of electron microscopy (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 27 (1994), S. 46-60 
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    ISSN: 1059-910X
    Keywords: Salivary gland ; Tumor ; Differentiation ; Classification ; Experimental studies ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Electron microscopy has a limited role in the diagnosis of primary salivary gland tumors, although it can be helpful in metastatic lesions of possible salivary gland origin. The diversity of subtypes in salivary gland tumors, as well as the range of histomorphology within any one subtype, is unparalleled in any other human tumor. This and their relative infrequency causes diagnostic problems for pathologists. Ultrastructural techniques have been of major importance in determining the inter-relationship of these tumors for classification purposes, revealing the subtle variations in common cellular differentiation pathways, determining the organization of tumor cells, and displaying the importance of extracellular matrix materials in establishing diagnostic criteria for each of the many subtypes. Electron microscopy has also been valuable in non-neoplastic salivary gland disease and has an increasing role in experimental studies involving tissue from human and animal salivary parenchyma. © 1994 Wiley-Liss, Inc.
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    Cytochrome c oxidase: Structural studies by electron microscopy of two-dimensional crystals (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 27 (1994), S. 319-332 
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    ISSN: 1059-910X
    Keywords: Cytochrome oxidase ; Electron microscopy ; Image processing ; Electron transport ; Mitochondria ; Membrane protein ; Membrane structure ; Protein structure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Cytochrome c oxidase is a complex integral membrane protein consisting of 13 different polypeptide chains and four metal centers having a total molecular weight of approximately 200,000 daltons. It can be isolated in two 2-dimensional crystalline forms differing in aggregation state of the enzyme. One crystal form consists of cytochrome oxidase dimers (approximately 400,000 daltons) embedded unidirectionally in the lipid bilayer of a collapsed vesicle while the other form consists of crystalline sheets of cytochrome oxidase monomers. Both crystal forms have been studied by electron microscopy during the past two decades, and this paper summarizes the results of early structural studies as well as more recent results applying techniques of cryelectron microscopy and digital image processing. The structure of frozen-hydrated cytochrome oxidase dimers at 20 Å resolution is discussed as well as the packing of monomers within dimers and the site of cytochrome c binding. © 1994 Wiley-Liss, Inc.
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    Image analysis of the extracellular matrix (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 28 (1994), S. 409-421 
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    ISSN: 1059-910X
    Keywords: Extracellular matrix ; Image analysis ; 3D reconstruction ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The epiphyseal growth plate and articular cartilage matrices were preserved by slam freezing and freeze substitution to optimally retain the native organization for both cellular and matrix components. These specimens were stained and examined using conventional electron microscopic methods. The highly integrated, proteoglycan-rich matrices were examined by computer image analysis using such parameters as distribution, connectivity, orientation, and a variety of morphometric analyses. Also, different aspects of electron tomography and 3D rendering of matrix vesicles and their associated mineral deposits from epiphyseal growth plates and turkey leg tendons are presented. © 1994 Wiley-Liss, Inc.
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    Light microscopic distribution of some cholinergic markers in the rat and rabbit locus coeruleus and the nucleus angularis grisea periventricularis of the domestic pig (Sus scrofa): A correlative electron microscopic investigation of cholinergic receptor proteins in the rabbit (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 29 (1994), S. 186-199 
    Details
    ISSN: 1059-910X
    Keywords: Acetylcholinesterase ; Choline acetyltransferase ; Muscarinic ; nicotinic receptor ; Immunohistochemistry ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Cholinergic modulation of locus coeruleus (LC) neurons evokes a variety of neuronal and behavioural effects. In an attempt to understand the LC cholinergic circuit, several markers has been investigated and compared. (Immuno)-histochemical and autoradiographic methods have been used on rat, rabbit, and pig tissue. To identify the boundaries of the LC in each of these species, sections through the entire brainstem have been stained for tyrosine hydroxylase. The results that the pig does not possess a LC proper that conforms to the accepted features of this cell group. However, in this location fusiform cells reminiscent of LC interneurons are still present. This group of fusiform neurons has been named the nucleus angularis grisea periventricularis (NAGP).LC cells of the rat and rabbit show strong acetylcholinesterase (AChE) activity. In the pig the NAGP is markedly free from AChE staining. Muscarinic binding sites are densely distributed over the rabbit LC and adjacent region. The rat and rabbit LC neurons synthesise both muscarinic (mAChR) and nicotinic receptor protein (nAChR). In the pig NAGP region mAChR and nAChR positive cell bodies are almost absent, while some nAChR immunoreactive dendrites are present. The light microscopic data in the rabbit have been confirmed by electron microscopic analysis.It is concluded that the general concept of a noradrenergic LC that is present throughout mammals is questionable. At present, choline acetyltransferase immunoreactive terminals that closely correspond to the other cholinergic components in the rat or rabbit LC have not been observed. However, in these species the cholinergic sensitivity of LC cells is mediated via both muscarinic and nicotinic receptors on somata and dendrites. © 1994 Wiley-Liss, Inc.
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    Subcellular distribution of peptides associated with gastric mucosal healing and neoplasia (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 234-247 
    Details
    ISSN: 1059-910X
    Keywords: Immunolocalisation ; Electron microscopy ; Ultrastructure ; hSP ; pS2 ; TFG α ; EGFR ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The trefoil peptides pS2 and human spasmolytic peptide are putative growth factors, particularly associated with mucus-producing cells of the gastrointestinal tract including those of the stomach. The receptor for transforming growth factor alpha (TGF α) takes its name from one of its alternative ligands, epidermal growth factor and is called the epidermal growth factor receptor. Although there is immunoreactive epidermal growth factor in the stomach, it is TGF α and the epidermal growth factor receptor that are abundant. Immunolabelling at electron microscope level allows for subcellular localisation of antigens; pS2 and human spasmolytic peptide co-localise to cytomembranes, including the Golgi apparatus, and thecae of surface/pit mucous cells. TGF α is abundant on the membranes of tubulovesicles of parietal cells and is also present in chief cells: in mucous producing cells it can be detected but not in association with mucous. The distribution of the epidermal growth factor receptor mimics that of TGF α but with preferential clustering on the basolateral membranes of gastric cells. The trefoil peptides are associated with healing and probably act, together with mucus, to protect the gastric mucosa and maintain a viable environment. TGF α, transduced via the epidermal growth factor receptor, inhibits gastric acid secretion, thus aids the trefoils in the maintenance of a gastric microenvironment conducive to healing after damage. TGF α, however, is also a potent mitogen; while this property plays a vital part in repairing mucosal defects, if this peptide or indeed its receptor are overexpressed, the result can be neoplasia. © 1995 Wiley-Liss, Inc.
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    Ultrastructure of human parathyroid cells in health and disease (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 32 (1995), S. 164-179 
    Details
    ISSN: 1059-910X
    Keywords: Parathyroid gland ; Hyperparathyroidism ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Parathyroid glands (n = 271) removed from 130 patients were examined by light and electron microscopy. A standardized method of tissue processing was employed and morphometry was performed. The aim of the paper is to provide a description of the human parathyroid chief cell ultrastructure in health and disease, with quantitative evaluation of structures involved in secretion of parathyroid hormone in a large case series, and to discuss their role in current diagnostic histopathology. The patients were euparathyroid (n = 10), or affected by primary (n = 97), secondary (n = 8), or tertiary (n = 15) hyperparathyroidism. In normal glands, solid parenchyma was composed of chief cells, large clear cells, transitional-oxyphil cells, and oxyphil cells. Chief cell hyperplasia, pseudo-adenomatous hyperplasia, adenoma, water-clear cell hyperplasia, and carcinoma were the most usual forms of parathyroid disease responsible for primary hyperparathyroidism. In chief cell hyperplasia, all the parathyroid glands were enlarged and the chief cells were in an active state of hormone secretion, with a large Golgi complex, abundant rough endoplasmic reticulum (RER), small lipid droplets, and tortuous plasma membrane. In pseudo-adenomatous hyperplasia, one gland was enlarged and the others displayed a normal size; however, electron microscopic examination and morphometric analysis showed that all the glands had active cells. Adenomas displayed a pattern similar to those of pseudo-adenomatous hyperplasia, with one gland enlarged and the others of normal size. However, ultrastructural examination and morphometry showed that the normal-size glands were hypo-active. Water-clear cell hyperplasia showed cells filled with cytoplasmic vacuoles. In these cells, structures with intermediate features between secretory granules and vacuoles were visible. Nucleo-cytoplasmic atypias were frequently visible in parathyroid carcinoma cells. In secondary and tertiary hyperplasia, active chief cells were regularly mixed with oxyphil or transitional-oxyphil cells. The tertiary hyperplasia was characterized by RER-associated structures that were not found in the normal or other pathologic conditions. These results demonstrate that electron microscopy and morphometry represent useful tools in parathyroid histopathology. © 1995 Wiley-Liss, Inc.
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    Electron microscopic image analysis of cardiac gap junction membrane crystals (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 452-466 
    Details
    ISSN: 1059-910X
    Keywords: Connexins ; Intercellular communication ; Crystallization ; Electron microscopy ; Image analysis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Cardiac gap junctions play an important functional role in the myocardium by electrically coupling adjacent cells, thereby providing a low resistance pathway for cell-to-cell propagation of the action potential. Two-dimensional crystallization of biochemically isolated rat ventricular gap junctions has been accomplished by an in situ method in which membrane suspensions are sequentially dialyzed against low concentrations of deoxycholate and dodecyl-β-D-maltoside. Lipids are partially extracted without solubilizing the protein, and the increased protein concentration facilitates two-dimensional crystallization in the native membrane environment. The two-dimensional crystals have a nominal resolution of 16 Å and display plane group symmetry p6 with a = b = 85 Å and γ = 120°. Projection density maps show that the connexons in cardiac gap junctions are formed by a hexameric cluste rof α1 connexin subunits. Protease cleavage of α1 connexin from 43 to 30 kDa releases ∼13kDa from the carboxy-tail, and the projection density maps are not significantly altered. Uranyl acetate stain penetrates the ion channel, whereas phospho-tungstic acid is preferentially deposited over the lipid regions. This differential staining can be used to selectively probe the central channel of the connexon and the interface between the connexon and the lipid. The hexameric design of α1 connexons appears to be a recurring quaternary motif for the multigene family of gap junction proteins. © 1995 Wiley-Liss, Inc.
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    Ultrastructural characterization of neurons recorded intracellularly in vivo and injected with lucifer yellow: Advantages of immunogold-silver vs. immunoperoxidase labeling (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 30 (1995), S. 427-436 
    Details
    ISSN: 1059-910X
    Keywords: In vivo intracellular recording ; Electron microscopy ; Preembedding immunohistochemistry ; Frontal cortex ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Immunoperoxidase labeling of lucifer yellow provides a sensitive method for morphological characterization of neurons recorded intracellularly in vitro or in vivo. However, the reaction product is often so dense that it obscures ultrastructural details necessary for the analysis of synaptic contacts onto individually filled neurons. In the present study, we describe a silver intensification procedure using 1 nm gold labeling of lucifer yellow as an optimal means for immunocytochemically identifying single physiologically characterized neurons at the ultrastructural level. Single neurons in the frontal cortex of anesthetized rats were impaled in vivo and filled with lucifer yellow. The brians were then perfused with an acrolein fixative. Single vibratome sections through the recording site were reacted with a rabbit antibody directed against lucifer yellow followed by goat anti-rabbit 1 nm gold-labeled IgG and silver intensified. For comparison, additional sections were processed for immunoperoxidase detection of lucifer yellow. Labeled sections were processed for light microscopy or embedded in plastic for electron microscopy. The immunogold-silver label as well as peroxidase reaction product of lucifer yellow was readily detected in cell bodies, proximal and distal dendrites, and spines. However, in contrast to immunoperoxidase, the immunogold-silver reaction did not obscure subcellular orgnelles. Most importantly, the synaptic junctions formed by afferents to the filled neuron were more easily identifiable following the immunogold-silver procedure. This clear visualization of postsynaptic densities is essential for examining synaptic circuitry between afferents and physiologically characterized neurons. © 1995 Wiley-Liss, Inc.
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    Immunocytochemistry, autoradiography, in situ hybridization, selective stains: Complementary tools for ultrastructural study of structure-function relationships in the nucleus. Applications to adenovirus-infected cells (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 22-43 
    Details
    ISSN: 1059-910X
    Keywords: Adenovirus ; Autoradiography ; Biotinylated probe ; Cytochemistry ; Electron microscopy ; Immunocytochemistry ; In situ hybridization ; Replication ; Transcription ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A significant amount of new information on structure-function relationships in nuclei of adenovirus-infected cells has accumulated during the last decade as a result of the combined use of several new cytochemical techniques. Localization of viral DNA on ultrathin sections of infected cells has been investigated at the ultrastructural level by using specific DNA staining and immunocytochemistry with monoclonal anti-DNA antibodies. Both techniques, however, concomitantly visualize cellular and viral DNA. The specific stain for DNA reveals the configuration of the DNA molecules in the different nuclear substructures, whateer their synthetic activities. The immunodetection of DNA reveals that specific antibodies strongly bind to DNA of condensed host chromatin and to both encapsidated and nonencapsidated inactive viral genomes. However, the observation of an abnormally low level of labeling over the substructures in which synthetic activities of viral genomes are known to be intense demonstrates a serious limitation of this technique for the detection of active DNA. Postembedding in situ hybridization is the most useful method for identifying with certainty the structures containing defined nucleic acid sequences. By using a biotinylated viral DNA probe, in situ hybridization provides specific identification of structures containing either viral DNA or viral RNA molecules. In addition, with appropriate pretreatment of the sections, it is possible to reveal either all the viral DNA-that is, both double- and single-stranded DNA molecules (dsDNA, ssDNA)-or more specific species such as only ssDNA or only dsDNA molecules. The replicative and transcriptional activities of viral genomes are determined by high-resolution autoradiography. Autoradiography after a short pulse incorporation of appropriate radioactive precursors by infected cells reveals the sites of cellular and viral DNA replication or trancription. A short pulse followed by chase periods of different durations reveals the progressive migration of the cellular and viral synthesized products. The in situ distribution of the viral 72 kDa DNA-binding protein, a highly phosphorylated protein which protects the viral ssDNA, is revealed either by immunocytochemistry with specific antibodies or by the bismuth staining method which stains all highly phosphorylated proteins, including both cellular and viral proteins. The combined results of all these cytochemical procedures reveal the composition and functions of some of the structures induced by adenovirus infection. They demonstrate that viral genomes engaged in replication lead to the formation of replicative foci in which two compartments rapidly develop, one of which results from the aggregation of single strands of viral DNA and their accompanying 72 kDa protein. Conversely, ssDNA and 72 kDa protein are rare in the other compartment which is the main site of replication and transcription of viral genomes. The procedural aspects and the contributions of electron microscope cytochemistry to an understanding of the biology of Ad5 viruses can serve as a basic framework for the study of other biological systems. © 1995 Wiley-Liss, Inc.
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    Microwave fixation: Understanding the variables to achieve rapid reproducible results (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 32 (1995), S. 246-254 
    Details
    ISSN: 1059-910X
    Keywords: Electron microscopy ; Microwave fixation ; Microwave irradiation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The use of microwave irradiation for rapid chemical fixation of tissues in electron microscopy is a subject of current interest. The effect of water load size and location, sample placement in the oven cavity (hot or cold spots), and time on tissue preservation were examined. The use of a microwave container (4 dram vial) encased in 60 ml of ice in a 100 ml polyethylene beaker and a 0% power setting between two 100% power settings (time interval) provided reliable control of temperature during microwave irradiation. High brightness neon lights provided a quick and easy method to identify and map hot and cold spots within the oven cavity. Using microwave irradiation for rapid glutaraldehyde and osmium tetroxide fixation of tissues (Pacific yew needle and mouse kidney and liver) for electron microscopy yielded preservation equal or better than routine immersion fixation when a time interval, a cold spot (as the sample location), and an ice-encased vial were used during microwave fixation. These adaptations provided reliable control of fixation conditions in an 800 watt laboratory microwave oven. © 1995 Wiley-Liss, Inc.
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    Position stabilization of EELS spectra (1985)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985), S. 167-169 
    Details
    ISSN: 0741-0581
    Keywords: Electron microscopy ; EELS ; feedback system ; peak stabilization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The position of the zero-loss peak in electron energy-loss spectra was sensed with a double photo diode. A signal, proportional to the disturbances from a central position, was amplified and fed back into a deflection coil in order to compensate for the origin of the disturbances. Thus, slow variations of the position of characteristic edges in the EEL spectrum could be reduced by a factor 100, and 60 Hz oscillations could be reduced by a factor 5.
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    A deposition technique for the imaging and analysis of protein interactions with metal and semiconductor surfaces (1985)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985), S. 285-292 
    Details
    ISSN: 0741-0581
    Keywords: Electron microscopy ; Edge-projection TEM ; Field-emission ; Rho protein ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A new technique for placing biological molecules on metal, insulator, and semiconductor surfaces is described. The procedure requires only 10 μl of solution containing molecules at a concentration of 0.1 - 10 μg/ml. The use of a buffer that does not affect metal substrates, the possibility of fixing the molecules in solution prior to deposition, and the ability to minimize surface tension forces during air drying are other features of the new protocol. Simultaneous deposition on TEM grids and highly curved substrates permits biomolecular adsorption on technologically interesting materials to be visualized in the transmission electron microscope.
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    Computer simulation and analysis of high-resolution electron microscope images and diffraction patterns with partial coherence, hollow cone illumination, and virtual apertures (1984)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 1 (1984), S. 107-130 
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    ISSN: 0741-0581
    Keywords: Phase contrast ; Computer simulation ; Partial coherence ; Electron microscopy ; Convergent beam ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A general method for computing high-resolution conventional transmission electron microscope images and diffraction patterns, when there are different types of partially coherent illumination conditions, is described. Examples of convergent beam, hollow cone, and virtual aperture illumination conditions are given in the context of interpreting image features. A comparison of real and computed diffraction patterns shows that, in practice, many innovative imaging modes are possible, which can be verified prior to real microscope experiments.
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    Immunolocalization of Alpha-Actinin in Adult Chicken Skeletal Muscles (1987)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 6 (1987), S. 357-366 
    Details
    ISSN: 0741-0581
    Keywords: Electron microscopy ; Immunolabeling ; Skeletal muscle ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Immunoelectron microscopy techniques were used to localize alpha-actinin within the Z lattice of adult skeletal muscles. Analysis of electron micrographs by direct visualization demonstrated that anti-alpha-actinin Fab fragments bound throughout the Z lattice. A low-resolution scanning densitometry technique was developed to quantitate the visual increase in the density of the Z lattice. These techniques did not allow determination of the particular component of the Z lattice, amorphous matrix, axial filaments, or cross-connecting filaments with which the antibody was associated. Therefore, additional techniques, including direct measurement of filament diameters and optical diffraction, were utilized in determining which components of the Z lattice bound anti-alpha-actinin Fab fragments. These analyses suggest that the antibody binding is distributed evenly throughout the lattice, along the filaments, and between them and is confined to the region of double overlap of the ends of the thin filaments.
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    Fungal infections in the acquired immunodeficiency syndrome (1988)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 8 (1988), S. 115-131 
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    ISSN: 0741-0581
    Keywords: Electron microscopy ; Fungal diagnosis ; Fungal therapy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Defects in cell-mediated immunity caused by infection with the human immunodeficiency virus (HIV) render AIDS patients particularly susceptible to fungal pathogens. Signs and symptoms of serious infection may be nonspecific, and early diagnosis and institution of antifungal therapy is essential to decrease morbidity and mortality in this patient population. In a symptomatic individual, invasive procedures are often required to establish a microbiologic diagnosis, and histopathologic examination of tissue by light and electron microscopy is often the first indication of a serious fungal infection in an AIDS patient.
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    Evaluation of high-resolution electron microscopy as a method for studying Y-Ba-Cu-O superconductors (1988)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 8 (1988), S. 273-284 
    Details
    ISSN: 0741-0581
    Keywords: Superconductors ; Electron microscopy ; Perovskites ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: High-resolution transmission electron microscopes operating at 300 and 400 kV were used to investigate the crystallography and microstructure of the perovskitelike YBa2Cu3O7-x. In this paper, we evaluate the performance attainable with these microscopes both empirically and by computer modelling. Based upon the assumption that oxygen may be a key to superconductivity properties, we have also investigated the visibility of the oxygen sites as well as the heavier yttrium and barium ion positions and the lighter Cu atom positions. We propose a scheme for observing different twin orientations in these structures and hence the oxygen atom positions seen in projection for the [100] and [010].Our observations of both thick and thin regions of Y-Ba-Cu-O materials are reported as well as the problems of adjusting microscope parameters and specimen alignment to obtain interpretable images. We also give a preliminary report on the effects of heat treatment as seen in high-resolution micrographs to assess disorder of the heavy atoms and oxygen vacancies.
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    Structure of the M Band (1987)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 6 (1987), S. 131-141 
    Details
    ISSN: 0741-0581
    Keywords: Skeletal muscle ; Myofibrils ; Fish ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: We have studied the structure of the M band in fish skeletal muscle using thin sectioning and deep-etching rotary shadowing. A reconstruction of the M band from these images shows it to be formed by obliquely arranged struts, which join the thick filaments to each other. Thickening of the thick filaments' profiles and nodal points where the struts cross each other are responsible for the fine sublines visible in longitudinal sections of the M band region.
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    Ultrastructural morphometric image analysis applied to estimation of condensed chromatin in normal and neoplastic lymphocytes (1985)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985), S. 597-609 
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    ISSN: 0741-0581
    Keywords: Electron microscopy ; Morphometry ; Lymphocytes ; Lymphoma ; Nucleus ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Currently, quantitative studies of malignant lymphoma are being performed in an attempt to improve the classification of non-Hodgkin's lymphoma (NHL) for diagnostic, prognostic, and therapeutic purposes. Morphometric image analysis is one method that can be employed in cases of NHL to obtain objective data of nuclear parameters; condensed chromatin being a compartment of the nucleus best measured at the ultrastructural level. This report assesses similarities or differences in the amount, distribution, and arrangement of condensed chromatin in nuclear profiles of normal and neoplastic lymphocytes in human surgical biopsy specimens. Morphometric data derived from electron micrographs of lymphocytes in germinal centers of lymph nodes with reactive hyperplasia (three cases) and small cell types of NHL two examples of malignant lymphoma, well differentiated lymphocytic type (ML, WDL) and three cases of malignant lymphoma, poorly differentiated lymphocytic type (ML, PDL) are compared. Results indicate that the distribution of condensed chromatin, i.e., the size of aggregates, and their spatial placement within the nucleus varies more than the amount (both mean area per profile or mean volume) of this nuclear parameter, and that this applies to normal as well as neoplastic lymphocytes. When a series of condensed chromatin parameters were statistically compared, no major differences could be detected between lymphocytes in normal tissues and those in ML, WDL and ML, PDL, but considerable differences were found in each of the nuclear morphotypes in the individual cases within the groups. This degree of variation in nuclear characteristics within normal tissues and the two lymphoma categories has not been previously recognized. Clearly, the technique of morphometric analysis, as applied to electron micrographs, can provide new and useful data that must be appreciated if classification schemes currently used in NHL are to improve and reflect biologic considerations.
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    Mycobacterium Avium-intracellulare complex infections in the acquired immunodeficiency syndrome (1988)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 8 (1988), S. 105-113 
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    ISSN: 0741-0581
    Keywords: Electron microscopy ; Histopathology ; Mycobacterium diagnosis ; Mycobacterium therapy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: This reviw examines an important bacterial infection in acquired immunodeficiency syndrome (AIDS). Despite occasional infections with bacteria such as Streptococcus pneumoniae, Haemophilus influenzae, Salmonella, and Nocardia in patients with AIDS, the primary problems of AIDS and invading bacterial infections center around mycobacteropsos. A unique feature of AIDS has been the common identification of disseminated infections with Mycobacterium avium-intracellulare. The following discussion examines our present understading of this group of organisms and how they interact with the compromised host.
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    Freezing and drying of biological tissues with a toggle-link helium freezer and an improved freeze-drying apparatus: Application to neuropeptide immunocytochemistry (1986)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 4 (1986), S. 315-328 
    Details
    ISSN: 0741-0581
    Keywords: Electron microscopy ; Immunocytochemistry ; Enkephalin ; Brain ; Liver ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A freezing apparatus has been developed for bringing blocks of tissue into contact with a block of sapphire chilled to 17°K. A toggle linkage minimizes rebound by slowing the rate of approach of the tissue to the cold surface to a velocity of zero. A glove box limits condensation on the surface of the sapphire, and a miniature moist chamber protects the specimen from drying and premature freezing. About 50 blocks of tissue can be frozen in an hour and a half by using 5 liters of liquid helium. The tissue is then frozendried at controlled temperature, fixed with OsO4 vapor, and infiltrated with epoxy resin in a simple bench-top freeze-drier without breaking vacuum. About two-thirds of the blocks are useful for electron microscopy. Brain tissue frozen and dried by using these methods retains enough immunoreactivity for enkephalin in plastic sections to permit its detection with immunohistochemistry by using both the light microscope (with immunofluorescence) and the electron microscope (with colloidal gold).
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    Image registration in electron microscopy: Application of a robust method (1988)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 10 (1988), S. 27-33 
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    ISSN: 0741-0581
    Keywords: Electron microscopy ; Image processing ; Image registration ; Robustness ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The geometric registration of two electron microscopic images generally is performed by maximizing the cross-correlation coefficient between them. We show that a new similarity measure (the number of sign changes) is useful for performing simultaneously geometric and gray-level registration. This method is robust, which means that it provides a good estimation of the parameters even in the presence of outliers that cannot be described by the registration model.
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    Procedural guide to specimen handling for the ultrastructural pathology service laboratory (1987)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 6 (1987), S. 255-301 
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    ISSN: 0741-0581
    Keywords: Fixation ; Processing ; Electron microscopy ; Human biopsies ; Diagnosis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Transmission electron microscopy serves a useful and often diagnostic purpose in the analysis of human disease. The emerging discipline of ultrastructural pathology serves a much wider field than that of kidney pathology and, of necessity, requires two essential elements. These are (1) the interpretive knowledge which covers all cells in all tissues which compose all organs, their normal substructural composition, and the ultrastructural expression of all of the basic mechanisms of the pathobiology of human disease, and (2) technically excellent preparations of these varied specimens.In this review, we emphasize the technical aspects necessary for the preparation of these specimens. These include the handling of varied specimens from the time of interruption of blood flow to the sample until fixation, fixation methodology, and routine processing methods for electron microscopy. Specialized techniques that are readily accomplished in an ultrastructural pathology service laboratory are also described. These include methods for the demonstration of glycogen, peroxidase(s), the glycocalyx. We also describe the preparation of permanent, alkaline Giemsa-stained 1-μm plastic sections for light microscopic diagnosis, the use of an agar-pelleting technique to change cell suspensions into readily handled blocks, and the use of Spurr's (J. Ultrastruct. Res. 26:31, 1969) low viscosity embedding for all skin and heavily collagenized specimens.The diagnostic report for individual samples can routinely be available within 24 hours of specimen arrival in the ultrastructural pathology laboratory with the methods we review here. Examples of these varied samples of human tissues and cells and methods for preparing them are illustrated. We have found such methods useful for diagnostic purposes, e.g., to identify the site of origin of a brain metastasis as the alveolar cell (type II pneumocyte) of the lung, based on the presence of typical lamellar (surfactant) bodies in the metastatic tumor cells (Dvorak and Monahan-Earley: Norelco Reporter 32:29-36, 1985c), as well as to describe for the first time a new tumor, such as the gut autonomic nerve (GAN) tumor (Walker and Dvorak: Arch. Pathol. Lab. Med. 110:309-316, 1986) or a cell injury process, axonal necrosis, to be characteristic of Crohn's disease (Dvorak et al.: Hum. Pathol. 11:620-634, 1980d; Dvorak and Silen: Ann. Surg. 201:53-63, 1985).
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    Quasicrystals and noncrystallographic symmetry (1987)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 7 (1987), S. 277-282 
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    ISSN: 0741-0581
    Keywords: Electron microscopy ; Electron diffraction ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: New findings on quasicrystals with icosahedral, octagonal, decagonal, and dodecagonal symmetries obtained recently in the Beijing Laboratory of Electron Microscopy, Chinese Academy of Sciences, are presented. Special emphasis is put on the relation between quasicrystalline and crystalline structures. The important role played by electron diffraction and high-resolution electron microscopy in revealing these quasiperiodic structures is pointed out.
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    Molecular genetics and structure of the human immunodeficiency virus (1988)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 8 (1988), S. 17-40 
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    ISSN: 0741-0581
    Keywords: Electron microscopy ; Heteroduplex mapping ; Lentiviruses ; Retroviruses ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A novel human lymphotropic virus capable of crippling the immune system by infecting and destroying T4 antigen-positive cells is now known to be the etiologic agent of the acquired immune deficiency syndrome (AIDS). The AIDS or human immunodeficiency virus (HIV) belongs to a family of RNA viruses called retroviruses. Several strains of HIV have been molecularly cloned, and DNA sequence comparisons have established that the proviral DNA genome is 9.7 kilobase pairs. The genome possesses characteristic retrovirus features including structural genes, flanked by long terminal repeats, in the order gag, pol, and env and, in addition, four unique nonstructural genes, several of which appear to be essential in regulating virus replication. Electron microscopy has played an important role in elucidating structural, genetic, and molecular properties of HIV and has aided in its classification as a member of the Lentivirnae retrovirus subfamily. Heteroduplex mapping methodologies pertinent to these findings are described. Although the relationships show considerable divergence, the similarities between HIV and lentiviruses are profound and encompass an indistinguishable morphology, genome sequence homology and topography, genomic diversity, and overlapping biology, including a preference for infecting cells of the immune system, a cytopathic effect in vitro, and the ability to produce a persistent, slowly progressing, degenerative disease in vivo. The newest HIV class (HIV-2) has recently been molecularly characterized. HIV-2 also bears all the hallmarks of a lentivirus but is more closely related to simian immunodeficiency viruses than the previously described HIV-1, despite a similar biology. The HIV-lentivirus phylogenetic relationship has broad implications for the AIDS disease process and has given new importance to the study of the natural history and pathogenesis of animal lentiviruses in searching for clues to prevent the spread of AIDS.
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    Utilization of digital image processing to study dynein arms (ATPase) in normal and immotile cilia (1988)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 8 (1988), S. 159-172 
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    ISSN: 0741-0581
    Keywords: Gray scale enhancement ; Immotile cilia syndrome ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Tracheal ciliary cross sections were examined with scanning transmission electron microscopy and the resultant images were digitized for image enhancement. A gray-scale histogram of each ciliary image was produced and manipulated to enhance the image for dynein arms. Tracheal epithelial tissue from the pig, rabbit, and dog, including dogs with immotile cilia syndrome, was examined by using this technique. Tissue from each animal was fixed with each of three different fixatives and sections were evaluated for preservation of dynein arms. The same fixative did not consistently provide optimal fixation for ciliary dynein arms in all three species examined. Each species, therefore, must be evaluated to determine the optimal fixative for preservation of normal ciliary ultrastructure. Digital image processing provides a mechanism for enhancing dynein arms in situ without the need for addition of special stains or the use of techniques such as image summation. With this technique it has been shown that about two-thirds of outer dynein arms are partially or completely missing on cilia from dogs with immotile cilia syndrome.
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    Structure of superconducting thin films of YBa2Cu3O7-x grown on SrTiO3 and cubic zirconia (1988)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 8 (1988), S. 263-272 
    Details
    ISSN: 0741-0581
    Keywords: High Tc superconductors ; Electron microscopy ; HREM image stimulations ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Thin films of the superconductive oxide YBa2Cu3O7-x have been made by electron-beam coevaporation of the metals in an oxygen atmosphere onto single-crystal {001}-oriented SrTiO3 and yttria-stabilized zirconia (YSZ) substrates. The oxide films were superconducting in the as-deposited state (Tc = 81-83K, Jc = 106 A/cm2 at 4.2K). Bright-field imaging, selectedarea diffraction (SAD), and high-resolution imaging in the transmission electron microscope were used to characterize the microstructure of these films. All of the films were polycrystalline. On SrTiO3 the films were oriented, for the most part, with {110} parallel to the substrate surface. On YSZ, two microstructures were observed: one with smaller rectangular grains oriented with (100) or (010) parallel to the substrate surface and the other with (001) parallel to the surface (i.e., c-axis up).
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    Fine structural cytology of the adenohypophysis in rat and man (1988)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 8 (1988), S. 401-432 
    Details
    ISSN: 0741-0581
    Keywords: Electron microscopy ; Immunoelectron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The present review deals with the use of electron microscopy in the identification of pituitary cell types as well as the assessment of their functional state, in rat and man. Application of immunoelectron microscopy, especially immunogold techniques, utilizing multiple labeling in establishing differentiation and hormone content of cell types, is emphasized. Recent evidence of plurihormonality in various pituitary cell types indicates that the once axiomatic one cell-one hormone theory is untenable and that the present perception of pituitary cell types and their function requires modification. Detection of hormonal and nonhormonal substances in pituitary cell types, not associated with their known endocrine function, suggests that hypophysial cells may have yet unknown roles, possibly in the realm of paracrine and autocrine regulation.
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    Differential morphometric values induced in Golgi apparatus of higher plant cells by aldehyde and permanganate fixation (1989)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 11 (1989), S. 1-8 
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    ISSN: 0741-0581
    Keywords: Electron microscopy ; Fixation methods ; Golgi apparatus morphometry ; Onion roots ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: In order to determine the best conditions to carry out quantitative ultrastructural studies in plant specimens, five different fixation techniques, including some of the most reported electron microscopy fixatives (glutaraldehyde-paraformaldehyde, osmium tetroxide, potassium permanganate), were assayed in onion root meristems to check their ability to induce morphometric changes in Golgi apparatus ultrastructure. Although the parameters evaluated showed in all cases the same tendency, values obtained after permanganate fixation were always higher than those found after aldehyde techniques (especially aldehyde-osmium). Aldehyde followed by osmium fixation appears as the most indicated fixation method when accurate quantitative ultrastructural studies are to be developed.
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    A Stopped-flow/rapid-freezing machine with millisecond time resolution to prepare intermediates in biochemical reactions for electron microscopy (1990)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 16 (1990), S. 160-166 
    Details
    ISSN: 0741-0581
    Keywords: Stopped-flow ; Rapid-freezing ; Freeze-fracture ; Electron microscopy ; Rapid reactions ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: We have developed an instrument capable of freezing transient intermediates in rapid biochemical reactions for subsequent freeze-fracturing, replication, and viewing by transmission electron microscopy. The machine combines a rapid mixing unit similar to one widely used in chemical kinetics (Johnson, 1986) with a propane jet freezing unit previously used to prepare static samples for freeze-fracturing (Gilkey and Staehelin, 1986). The key element in the system is a unique thin-walled flow cell of copper that allows for injection and aging of the sample, followed by rapid freezing. During freeze-fracturing, a tangential cut is made along the wall of the flow cell to expose the sample for etching and replication. The dead time required for mixing and injection of the reactants into the flow cell is less than 5 ms. Electronic controls allow one to specify, on a millisecond time scale, any time above 5 ms between initiation of the reaction and quenching by rapid freezing.
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    Evaporation during preparation of unsupported thin vitrified aqueous layers for cryo-electron microscopy (1990)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 16 (1990), S. 351-355 
    Details
    ISSN: 0741-0581
    Keywords: Drying ; Electron microscopy ; Frozen hydrated specimen ; Specimen preparation ; Vitrified specimen ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Evaporation of water cannot be fully avoided when an unsupported thin vitrified film of an aqueous suspension is prepared for cryo-electron microscopy. This results in increasing concentration of solute which could affect the observed material. We have quantitatively studied this effect by measuring the contrast of polystyrene spheres in a metrizamide solution. The drying effect is generally negligible when specimens are prepared on a hydrophilic perforated support but it is frequently important when hydrophobic films are used instead. A flow of humid air, double blotting with minimal exposure of the thin liquid film to the atmosphere, or an automatic plunger optimizing the blotting conditions are simple methods for reducing drying effects. With this third device acting on a hydrophilic supporting film, the increase of solute concentration is limited to less than 20%.
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    URL: http://dx.doi.org/10.1002/jemt.1060160407
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    Determination of vesicle size distributions by freeze-fracture electron microscopy (1991)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 17 (1991), S. 459-466 
    Details
    ISSN: 0741-0581
    Keywords: Vesicle ; Freeze-fracture ; Electron microscopy ; Size distributions ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The most common electron microscopic technique for obtaining information on size distributions of uncollapsed membrane vesicles is based on the method of van Venetie (1980). This technique involves the sizing of only those vesicles that were freeze fractured at their equatorial planes. As a result, only a small number of images can be used to generate size distributions. Further, the technique is susceptible to systematic error. An alternate approach is to consider the complete distribution of image sizes and use this distribution to determine the average size and distribution of the vesicles. It is shown that the mean vesicle size is 4/π times the mean image size. As well, a parameter, m, which can be determined from the image distribution, can be used to characterize the vesicle distribution. The advantage of this new approach is that images of all vesicles are used, leading to a statistically better determination of vesicle sizes.
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    URL: http://dx.doi.org/10.1002/jemt.1060170409
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    Ultrastructural investigation of neurons identified and localized using the confocal scanning laser microscope (1991)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 18 (1991), S. 82-90 
    Details
    ISSN: 0741-0581
    Keywords: Biocytin ; Electron microscopy ; Diaminobenzidine ; Hippocampus ; Horseradish peroxidase ; Spines ; Varicosities ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Studies of labeled neurons at the light-microscopic level often pinpoint a substructure of particular interest, i.e., a synapse or a spine. An ultrastructural investigation would explain a lot about how these structures arose, how they function, and how they are regulated. Finding a small region in a large block can require constant checking during sectioning, until past the structure. In our pursuit of the synaptic structure of varicosities on the axons of neurons identified physiologically and morphologically at the light level, we have combined confocal scanning laser microscopy (CSLM) with conventional and high-voltage electron microscopy (EM). CSLM images were collected in the reflection mode to view neurons filled with horseradish peroxidase and stained with nickel-intensified diaminobenzidine, which is compatible with EM. The CSLM optical sections provided a record of what one should expect to see at regular intervals throughout the depth of the tissue block. We have shown that the CSLM greatly simplified the task of localizing small structures in brain tissue prepared for EM.
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    URL: http://dx.doi.org/10.1002/jemt.1060180112
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    Ultrastructural cryoimmunocytochemistry is a convenient tool for the study of DNA replication in cultured cells (1991)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 18 (1991), S. 91-105 
    Details
    ISSN: 0741-0581
    Keywords: BrdU incorporation ; Cultured cells DNA replication ; Electron microscopy ; EM immunocytochemistry ; Immunocytochemistry ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: In the present study, we have optimized an immunocytochemical ultrastructural approach for in situ localization of newly synthesized DNA in unsynchronized as well as in synchronized human HeLa cells and in exponentially growing mouse P815 cells, which had incorporated bromodeoxyuridine (BrdU) during short pulses varying from 1 to 20 minues. The incorporated BrdU was detected in hydrolyzed ultrathin cryosections or Lowicryl sections by means of a monoclonal antibody, revealed by secondary colloidal gold-labeled probes. The results demonstrate our ability to study, with high resolution and reproducibility, DNA replication during consecutive periods of the S-phase, which is monitored by the incorporation of tritiated thymidine. In addition, this approach allows one to perform a concomitant mapping of replicated DNA and various enzymes of the replisome.
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    URL: http://dx.doi.org/10.1002/jemt.1060180202
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    Ultrastructure of the seminiferous epithelium and intertubular tissue of the human testis (1991)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 19 (1991), S. 215-240 
    Details
    ISSN: 0741-0581
    Keywords: Spermatogenesis ; Sertoli cells ; Leydig cells ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The ultrastructural features of the human testis are reviewed with emphasis upon the process of spermatogenesis and the cytology of the Leydig cells. The seminiferous epithelium is structurally partitioned by the Sertoli cells into basal and adluminal compartments via the specialized tight junctions between the Sertoli cells. Spermatogonia reside in the basal compartment, and, via a series of cell divisions, produce the primary spermatocytes, which at the commencement of their development move into the adluminal compartment, and thus the lengthy process of meiotic maturation is initiated. The fine structure of primary spermatocytes is described together with the complex transformation of the spermatids into spermatozoa during the process of spermiogenesis. Earlier studies of the organization of the human seminiferous epithelium showed that germ cells at different developmental stages formed identifiable collections termed cell associations or stages, but since several stages were seen in a single tubule cross-section, this gave the impression of an extremely irregular pattern of spermatogenic development. When the topographic arrangement of germ cells was re-examined with the aid of computer modelling, a highly ordered distribution was revealed, conforming to a helical pattern based on the geometry of spirals. Thus spermatogenesis in the human testis is subjected to a precise regulation in keeping with the ordered arrangement of the germ cells seen in other mammalian species. The intertubular tissue of the human testis is composed of loose connective tissue containing blood vessels, occasional lymph capillaries, macro-phages, mast cells, and the Leydig cells which occur either as single cells or form small clusters. The Leydig cell cytoplasm contains an abundant supply of smooth endoplasmic reticulum and mitochondria with tubular cristae, both features being characteristic of steroidogenic cells. Human Leydig cells contain large Reinke crystalloids of variable size and number, but their function remains obscure. The frequent occurrence of paracrystalline inclusions within the cytoplasm of the human Leydig cell suggests that these elements are precursors of the Reinke crystalloids.
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    URL: http://dx.doi.org/10.1002/jemt.1060190208
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    Applications of freeze-fracture replication to problems in materials and colloid science (1989)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 13 (1989), S. 309-334 
    Details
    ISSN: 0741-0581
    Keywords: Freeze-fracture ; Electron microscopy ; Rapid freezing ; Dispersions ; Polymers ; Gels ; Liquid crystals ; Emulsions ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Understanding the relationship between the molecular structure and the macroscopic properties of polymer solutions and gels, oil-water-surfactant emulsions, lyotropic and thermotropic liquid crystals, colloidal dispersions, detergents, and other such “microstructured fluids” is essential to the optimal use of these commercially important materials. Modern rapid-freezing methods followed by freeze-fracture replication techniques are ideally suited to allow the direct visualization of the three-dimensional structure of the particles or units that make up the dispersion, while simultaneously revealing their orientation and distribution with molecular resolution. This paper reviews the necessary experimental conditions required to successfully exploit the freeze-fracture technique as it applies to microstructured fluid systems. The benefits and limitations of structural studies by freeze-fracture techniques as opposed to the more commonly used light, X-ray, and neutron-scattering methods are discussed. Freeze-fracture replicas can also be imaged by scanning tunneling microscopy to reveal directly three-dimensional fracture contours with improved resolution.
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    URL: http://dx.doi.org/10.1002/jemt.1060130406
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    Counting cells with stereology: Random versus serial sectioning (1990)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 14 (1990), S. 32-38 
    Details
    ISSN: 0741-0581
    Keywords: Electron microscopy ; Cell counts ; Nuclear shape ; Section compression ; Lung ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Counts of cells and nuclei from sections provide information central to studying structural changes in cells, tissues, and organs. This study considers some of the practical problems associated with counting cells with the newer random and serial sectioning methods of stereology and tests the hypothesis that similar cell counts can be obtained with both random and serial sectioning methods.Using irregularly shaped nuclei from alveolar cells of the goat lung, we compared cell counts derived from random (electron microscopic) and serial sectioning (light microscopic) methods. The results showed that both sectioning methods gave similar cell counts (107/cm3 of parenchyma) for type 1 epithelial cells (5.0 vs. 5.0; P=1.0), type 2 epithelial cells (8.6 vs. 9.8; P=0.42) and interstitial cells (34.6 vs. 33.4; P=0.64), provided that corrections were introduced for sectionrelated biases and that the nuclei of the random sectioning method were corrected for shape. We found counting biases of 5%-7% for nuclear shape and 16% for section compression. These observations support the hypothesis that similar cell counts can be obtained with random and serial sectioning, even when nuclei have irregular shapes.
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    URL: http://dx.doi.org/10.1002/jemt.1060140106
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    Preparation of biological tissue sections for correlative ion, electron, and light microscopy (1984)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 1 (1984), S. 299-309 
    Details
    ISSN: 0741-0581
    Keywords: Electron microscopy ; Ion microscopy ; Correlative microscopy ; Electron probe microanalysis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: In order to correctly interpret the chemical images obtained using ion microscopy (IM), it is useful to correlate them with the information provided by conventional light microscopy (LM), secondary electron imaging (SEI), backscattered electron imaging (BEI), and electron probe microanalysis (EPMA). Accordingly, we have devised a technique of specimen preparation which allows for the application of several different microanalytical techniques to a single histologic section mounted on the same substrate. Sections are cut onto polyester plastic coverslips (devoid of peaks for any element with atomic number 〉 9 using EPMA) and studied by LM. After a light rotary coating with carbon (to prevent charging), the section can then be examined by SEI, BEI, and EPMA. Specific areas can be marked for IM study either with an objective-mounted pin tissue microlocater, or by placing small pieces of metal foil, cut in specific geometric shapes, over features of interest. After sputter-coating the sample with platinum, metal-free shadows are visible using a low-power reflected light microscope available on a typical IM sample chamber as a guide for ion beam placement. The conductive coatings also minimize specimen charging during IM. Post-IM light microscopy, SEI, and BEI are used to confirm the location of specific areas probed in the IM experiments and to provide information on differential ion-sputtering artifacts and tissue contaminants. This new correlative technique should permit better understanding of the images obtained with these diverse instruments.
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    Ion milling of materials science specimens for electron microscopy: A review (1984)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 1 (1984), S. 405-414 
    Details
    ISSN: 0741-0581
    Keywords: Ceramics ; Electron microscopy ; Ion milling ; Specimen preparation ; Sputtering ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Ion bombardment to perforation is a common technique in the materials sciences by which thin specimens can be prepared for transmission electron microscopy. The process is not without complication and involves radiation damage to the specimen and tends not to preserve the initial specimen topology. Some of the more important facets of the ion-milling process, pertinent to such specimen preparations, are described.
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    Real time uses of color for electron microscopy via a television-rate digital frame store (1985)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985), S. 405-424 
    Details
    ISSN: 0741-0581
    Keywords: Electron microscopy ; Image processing ; Pseudo color ; Digital frame store ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: An on-line television-rate digital frame store device is utilized to provide color representations of a wide range of electron microscope images and image data. Various types of hardware devices in the frame store coupled with software manipulations via the host computer make rapid image acquisition, modification, measurement, and full-color display possible in real time either from micrographs or directly from an electron microscope. Lookup tables used in conjunction with grey-level image memories can be controlled from a menu display to provide a wide range of color-coding schemes and sequencing. It is also possible to use color graphics overlays and alpha numeric displays along with full-color image displays. This paper will describe many of the recent applications of color developed for electron microscopy studies of materials.
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    URL: http://dx.doi.org/10.1002/jemt.1060020502
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    Comparison of surface roughness of sections cut by diamond, sapphire, and glass knives (1987)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 6 (1987), S. 81-85 
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    ISSN: 0741-0581
    Keywords: Ultramicrotomy ; Thin sectioning ; Microtome knives ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Low-angle chromium metal shadowing was used to compare the surface roughness of ultrathin sections cut with diamond, sapphire, and glass knives. Surface roughness was less on diamond-cut and sapphire-cut sections than on glass-cut sections, and was greater over tissue than resin, and greatest over red blood cells and mitochondria. Surface roughness contributed to image density variation and thereby lowered contrast and informational content of the sectioned tissue.
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    A computer program for the systematic sampling of sections in microscopic morphometry (1985)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985), S. 481-487 
    Details
    ISSN: 0741-0581
    Keywords: Morphometry ; Electron microscopy ; Computer program ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A computer program is described that facilitates systematic and unbiased sampling in morphometry. Input data are coordinates of the four corners of a section as displayed in the position indicators of the microscope stage. Outputs are coordinate values in the form of a regular lattice that describes where to place the stage and perform the sampling on the section. In addition, some other data are provided by the program, such as total area of section, length of sides, etc. The program is written in BASIC but can be easily converted to other computer languages.
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    The preparation of ultrathin frozen sections for immunocytochemistry at the electron microscope level (1985)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985), S. 497-507 
    Details
    ISSN: 0741-0581
    Keywords: Ultrathin frozen sections ; Electron microscopy ; Immunocytochemistry ; Cryobiology ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A description of ultrathin frozen sectioning is presented. Small pieces of lightly-fixed but unembedded tissue are cryoprotected in 80% sucrose, mounted on chucks and frozen in liquid nitrogen. Frozen sections approximately 100 nm thick for electron microscopy are cut at about -90°C, using a cryosectioning unit mounted on a conventional ultramicrotome. Sections are picked up from the surface of the knife with a droplet of 80% sucrose, and are applied to membrane-coated EM grids at room temperature. The mounted sections are then used for EM immunocytochemistry. Essentially the same sectioning procedure can provide frozen sections 1 μm thick for light microscope immunocytochemistry.
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    URL: http://dx.doi.org/10.1002/jemt.1060020512
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    Detection of sulfur in fixed and embedded rat peritoneal mast cell granules by X-ray energy dispersive spectroscopy (1986)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 3 (1986), S. 347-356 
    Details
    ISSN: 0741-0581
    Keywords: Proteoglycans ; Rat mast cells ; Sulfur ; X-ray spectroscopy ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Purified rat peritoneal mast cells contained 3.3 × 10-5 gm SO4 and 2.2 × 10-8 gm Ca/106 cells. The molar ratio of S/Ca in the whole cell was 600:1. Frozen thin sections of unfixed mast cells contained only sulfur (S) in the granules when examined by X-ray energy dispersive spectroscopy (EDS). Mast cells fixed in 3% glutaraldehyde and 1.5% formaldehyde in 75% ethanol (Et/Ald) or in mixed buffered aldehydes and embedded in Epon 812 or the low viscosity resin diepoxyoctane (DEO) contained S in all granules and Ca in some of the granules measured. Neither element was found in the nucleus, cytoplasm, or resin. Isolated, Et/Ald fixed and embedded granules also contained S. The presence of Ca in the granules was artifactual in that the Ca was absorbed from water in the trough of the diamond knife and/or from the filter paper used to blot the sections dry. This phenomenon was investigated further. Sections of Et/Ald fixed and embedded mast cells were incubated with 5 × 10-6 to 10-2 M CaCl2. Ca was detectable in 100% of the granules incubated at concentrations ≥ 10-4 M and reached a constant S/Ca ratio of 2.0 at concentrations ≥ 10-3 M. Ca was not detectable in the nucleus, cytoplasm, or resin at 10-2 M. A plot of S versus Ca counts from the granules of cells incubated with 10-2 M CaCl2 was linear with a slope of 2.0 and a correlation coefficient of 0.88. Et/Ald fixed cells incubated with distilled H2O had fewer granules containing Ca, 10%, than unincubated cells, 77%. Further, H2O removed all Ca from Et/Ald fixed cells embedded in DEO. These studies show that S, which is present as SO4 on the proteoglycan heparin, is readily detectable by X-ray EDS in fixed and embedded cells. An artifact of the technique is that weak anionic sites, which are most probably carboxyl groups on the proteoglycan, can bind the divalent cation Ca and cause spurious localization.
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    Defect structure of superconducting YBa2Cu3O7-δ (1988)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 8 (1988), S. 285-295 
    Details
    ISSN: 0741-0581
    Keywords: Electron microscopy ; Vacancy ordering ; Phase transformation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The superconducting material Y1Ba2Cu3O7-δ has been investigated by electron microscopy. Special attention has been paid to the defects occurring in the material. Twinning on (110) or (110) planes is intrinsically related to the orthorhombicity, and when cooled slowly the twin bands are pseudoperiodic with an average width of ˜ 50 nm. The orthorhombic-tetragonal transition is reversible and diffusion controlled. Under particular conditions and in slightly reduced material a 2a0 X b0 superstructure resulting from vacancy ordering is formed. When kept in air under powder form the material seems to be unstable. Planar defects along (001) accompany the degeneration of the material.
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    Contamination of thin sections: Some observations on the cause and elimination of “embedding pepper” (1987)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 5 (1987), S. 59-63 
    Details
    ISSN: 0741-0581
    Keywords: Electron microscopy ; Postsection staining ; Section contamination ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A method is described for eliminating a form of contamination called embedding pepper that appears in, or on, thin sections following poststaining in lead citrate. The pepper is present most often in the matrixes of mitochondria, peroxisomes, and red blood cells. Formation of pepper can be prevented by treating the section with 0.5 N HCl or 1.0% ethylenediaminete-traacetic acid (EDTA) for 1-5 min before staining in uranyl acetate or lead citrate.
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    Postembedding ultrastructural immunocytochemistry of neural antigens on tissues previously processed for routine light and electron microscopy: Preservation of antigenicity up to 22 years after initial fixation (1987)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 5 (1987), S. 81-90 
    Details
    ISSN: 0741-0581
    Keywords: Immunocytochemistry ; Electron microscopy ; Colloidal gold ; Glial fibrillary acidic protein ; Neuron-specific enolase ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: 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.
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    URL: http://dx.doi.org/10.1002/jemt.1060050109
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    A computer program for morphometry of circular and elliptical profiles on the microscope (1987)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 7 (1987), S. 191-193 
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    ISSN: 0741-0581
    Keywords: Morphometry ; Computer program ; Electron microscopy ; Stereology ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: We describe a short computer program, which is written in Pascal language, to measure the diameter of circular and elliptical profiles in sections. Coordinate pairs on the microscope stage, corresponding to two or three points of a profile, are input to obtain its diameter. The program enables one to take measurements directly on the microscope, thereby reducing photographic work and caliper measurement. While the program is largely designed for electron microscopy, it also may be useful for light microscopy morphometry.
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    Some nanostructural features in ceramics (1987)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 7 (1987), S. 301-312 
    Details
    ISSN: 0741-0581
    Keywords: Electron microscopy ; Nanostructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Nanostructural features in some ceramics have been discussed and reviewed. Based on our research results and recent published investigations, many topics, such as grain, grain boundary, interface film, grain boundary engineering, microcrack, microdomain, nanodomain, domain boundary, and phase transformation, etc., have been dealt with; and many materials, such as Si3N4, β″-Al2O3, MgO, SiC, (Hg, Cd) Te, BNN, ZrO2, PLZT, CdSe, Ca10(PO4)6, (OH)2, etc., have been involved. The results are important to understand the relation between the structure and property of materials and to improve the materials' technology.
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    Ultrastructural and paraphenylene studies of degeneration in the primate visual system: Degenerative remnants persist for much longer than expected (1988)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 8 (1988), S. 179-183 
    Details
    ISSN: 0741-0581
    Keywords: Axonal degeneration ; Electron microscopy ; Human ; Visual pathways ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: It is a widely held belief that the products of axonal degeneration in the CNS are transitory and are caused by metabolic and phagocytic processes. However, recent light microscopic examinations of human and primate brains using the paraphenylene diamine staining method (PPD), which stains degenerating axons, have confirmed that the products of degeneration persist for years in visual pathways. The routine utilization of the PPD method for delineating human visual pathways requires further confirmation of axonal degeneration. Optic nerves, optic tracts, and lateral geniculate nuclei were collected from human brains that had clinical documentation of optic nerve damage prior to death. Optic nerves, optic tracts, and lateral geniculate nuclei taken from the brains of cynomolgus monkeys that had undergone enucleation 3 months to 1 year prior to sacrifice were also examined. All tissue was processed for electron microscopy; ultrathin sections were cut for electron microscopy, and consecutive sections were cut for light microscopy.In all cases, the homology of the degenerated processes was confirmed between the light microscopic (PPD) and the electron microscopic sections. Such ultrastructural examination demonstrates that the products of axonal degeneration remain in the primate visual system longer than previously supposed.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/jemt.1060080204
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    Morphology of the minipig kidney (1988)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 9 (1988), S. 213-234 
    Details
    ISSN: 0741-0581
    Keywords: Electron microscopy ; Nephron ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The minipig has a multilobar kidney with a wide cortex and short papilla. The vascular bundles are of a simple type. Although short and long looped nephrons are both present, the short looped kind predominates. The minipig has many morphological similarities to dog and human kidneys. One particularly unique feature of the minipig papillary collecting duct cells, however, is the presence of electron-dense granules in the basal cytoplasm which appear to be secreted into the lateral intercellular spaces, perhaps forming a water-tight seal in a manner analogous to membrane-coating granules found in the epidermis of skin.
    Additional Material: 45 Ill.
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    URL: http://dx.doi.org/10.1002/jemt.1060090302
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  • 89
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    Synaptic connections of neurones identified by Golgi impregnation: Characterization by immunocytochemical, enzyme histochemical, and degeneration methods (1990)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 15 (1990), S. 332-351 
    Details
    ISSN: 0741-0581
    Keywords: Identified neurones ; Synaptic contacts ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: For more than a century the Golgi method has been providing structural information about the organization of neuronal networks. Recent developments allow the extension of the method to the electron microscopic analysis of the afferent and efferent synaptic connections of identified, Golgi-impregnated neurones. The introduction of degeneration, autoradiographic, enzyme histochemical, and immunocytochemical methods for the characterization of Golgi-impregnated neurones and their pre-and postsynaptic partners makes it possible to establish the origin and also the chemical composition of pre-and postsynaptic elements. Furthermore, for a direct correlation of structure and function the synaptic interconnections between physiologically characterized, intracellularly HRP-filled neurones and Golgi-impregnated cells can be studied. It is thought that most of the neuronal communication takes place at the synaptic junction. In the enterprise of unravelling the circuits underlying the synaptic interactions, the Golgi technique continues to be a powerful tool of analysis.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/jemt.1060150404
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  • 90
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    Adrenal chromaffin cells as transplants in animal models of parkinson's disease (1989)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 12 (1989), S. 308-315 
    Details
    ISSN: 0741-0581
    Keywords: Adrenal medulla ; Electron microscopy ; Transplantation ; Plasticity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The field of neural transplantation has moved rapidly forward in the last decade. Initially, fetal cells were used as implants to investigate their potential to ameliorate deficits in animal models of Parkinson's disease. However, because of the moral and legal problems associated with the use of fetal tissues in humans, alternative sources of donor tissue were sought which possessed the structural and functional characteristics needed to improve motor function in Parkinsonian patients. To date, one of the most promising tissues being investigated is the adrenal medulla, whose chromaffin cells possess an inherent plasticity of form and function. Transplanted chromaffin cells currently are being studied by a variety of approaches, including electron microscopy, in mouse, rat, and primate models of Parkinson's disease. An overview of the role of the chromaffin cell in this exciting and clinically important arena is briefly reviewed, with an emphasis on the fine structure of implanted chromaffin cells.
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    URL: http://dx.doi.org/10.1002/jemt.1060120403
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  • 91
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    Ultrastructural demonstration of exocytosis in the intact rat adrenal medulla (1989)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 12 (1989), S. 316-322 
    Details
    ISSN: 0741-0581
    Keywords: Secretion ; Electron microscopy ; Tannic acid ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Evidence is presented for morphological proof of exocytosis in the rat adrenal medulla in situ. Techniques were modified to allow perfusion of the intact adrenal gland with secretagogues (or electrical stimulation) followed by tannic acid. Unstimulated specimens demonstrated exocytotic (omega-shaped) profiles filled with flocculent material. This flocculation was also seen in the intercellular space. Stimulation of the adrenal medulla also resulted in the appearance of exocytotic profiles and an accumulation of the flocculent mass. This was often most evident in the subendothelial space. This is the first demonstration of exocytosis in the rat adrenal medulla by electron microscopy. The techniques used in this study will be useful for studying the pathway of secretory products of the adrenal chromaffin cell before they enter the vascular system.
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    URL: http://dx.doi.org/10.1002/jemt.1060120404
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  • 92
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    Image analysis of mineralized and non-mineralized type I collagen fibrils (1991)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 18 (1991), S. 262-268 
    Details
    ISSN: 0741-0581
    Keywords: Collagen ; Mineral ; Calcification ; Tendon ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Turkey leg tendons at an early stage of mineralization have been thin sectioned and imaged by electron microscopy. At this stage collagen-associated mineral apatite was found to be present within both the gap and overlap zones. The earliest apatite occurs in a microcrystalline form which gives a rather generalized and characteristic density to both the gap and overlap zones; with subsequent development larger defined apatite crystals arise which span gap/overlap zones. Fourier transformation of such images revealed the major 67 nm axial repeat of the gap/overlap zone plus four other maxima corresponding to repeat spacings of 22, 16, 13, and 11 nm respectively. Computer imaging techniques were used to reconstruct images by using selected spatial frequencies from such transforms. In this manner the subperiodic distributions of mineral were visually enhanced. These subperiodicities are positioned in an asymmetric fashion over the entire D unit repeat aligning with the molecular orientation of the fibril. Analyses of both negatively stained collagen and computer-generated maps of collagen hydrophobicity were compared to the mineral distribution of collagen. Densitometric comparisons showed a positional correlation between the axial banding patterns of mineralized fibrils and those of negatively stained non-mineralized fibrils. Comparable spatial frequencies were also present in transforms between hydrophobic maps and mineral distribution of collagen. These results suggest that the lateral clusterings of hydrophobic residues which span the fibril at specific sites in both the gap and overlap zones serve to prohibit early mineral deposition. This observed hydrophobic influence in combination with the gap space appear as contributing factors in the observed axial distribution of mineral within collagen.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/jemt.1060180308
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  • 93
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    Ultrastructural localization of defined sequences of viral RNA and DNA by in situ hybridization of biotinylated DNA probes on sections of herpes simplex virus type 1 infected cells (1991)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 18 (1991), S. 336-353 
    Details
    ISSN: 0741-0581
    Keywords: Electron microscopy ; Lowicryl ; Herpes simplex virus type 1 infection ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The influence of fixation and enzymatic digestions on the ability of a denatured double-stranded DNA probe to bind specifically to related sequences of RNA and DNA in sections of Lowicryl embedded cells was investigated. Specificity of the hybridization was assessed using a biotinylated cloned subgenomic herpes simplex virus type 1 DNA fragment to localize viral nucleic acids in sections of infected cells. The probe was detected by anti-biotin antibodies and indirect immunogold labeling. Controls indicated that protease digestion of proteins from the section eliminated non-specific binding of the probe and labeling of endogenous biotin.Both formaldehyde and glutaraldehyde fixation retained viral RNA in protease digested sections. Its labeling was randomly and sparsely distributed over the fibrillo-granular network of the infected nucleus and over the ribosome-rich regions of cytoplasm.Labeling of single-stranded portions of viral DNA in protease-RNase digested sections was infrequent. It was located precisely over nucleoids of a few viral nucleocapsids whatever their location in the cell and their stage of maturation.Labeling of double-stranded viral DNA by denaturation of the DNA in the sections of Lowicryl embedded cells was possible after fixation with formaldehyde but not glutaraldehyde. Among several denaturation protocols, 0.5 N NaOH treatment was best for hybridization of both nonencapsidated and encapsidated viral DNA in protease-RNase digested sections. Free viral genomes were detected exclusively within the virus-replicating region of infected nuclei. Labeling of viral nucleoids was independent of their location in the cell. The high percentage of labeled viral nucleoids suggests that the related viral DNA sequence is not aggregated in the nucleoid but is extended and therefore numerous portions of this defined DNA sequence are accessible at the surface of the section for the binding of the probe.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/jemt.1060180403
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  • 94
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    Interrelationships of ultrastructure and function in the microvasculature of normal and ischaemic myocardium (1991)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 19 (1991), S. 429-438 
    Details
    ISSN: 0741-0581
    Keywords: Myocardium ; Blood vessels ; Electron microscopy ; Fixation ; Methods ; Ischaemia ; Reperfusion ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: This paper reviews various methods involving electron microscopy that have been used to investigate the ultrastructure of the vasculature of the normal and diseased heart. Whereas scanning electron microscopy is more commonly employed to record surface topography, it can be used to examine freeze-fracture planes within the myocardium and, using heavy-metal staining and back-scattered electron imaging, to examine large 2-μ-thick resin-embedded sections through the heart. The latter technique allows the comparison of structural alterations across the wall of the heart and thus accurate definition of the transmural progression of pathological processes. Transmission electron microscopy can then be used to provide more detailed information from precisely localised regions. Human myocardium can be usefully studied up to 12 hours post-mortem provided that suitable control material is included. Intravascular tracers including low-viscosity resin and nuclear track emulsion can be used to determine whether or not particular vessels allow flow at the time of fixation, and thus changes in the pattern of flow through the microvasculature due to ischaemia and reperfusion can be quantified and defined. Particular care is required in the fixation of ischaemic tissues because oxygen dissolved in the fixative can lead to the rapid formation of oxygen-free radicals on contact with the tissue. This produces artefactual reoxygenation damage characterised by membrane disruption and cell and organelle swelling, which has previously been attributed to ischaemic injury per se. Bubbling glutaraldehyde with nitrogen substantially reduces this artefact.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/jemt.1060190405
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  • 95
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    A multisample chamber for dehydration and critical point drying (1984)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 1 (1984), S. 199-201 
    Details
    ISSN: 0741-0581
    Keywords: Critical point drying ; Electron microscopy ; Ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The principles and methods for constructing an improved chamber for dehydration and critical point drying of multiple biological samples are described. The specimen chamber design is based on vertical positioning of the electron microscope grids or coverslips and permits minimal perturbation of laminar solvent flow past the specimens. This condition is requisite for optimal exposure of samples to solvents, which is necessary for complete dehydration and drying. Fragile samples, including chromosomes, critical point dried in the multisample chamber demonstrate crisp, well-preserved, three-dimensional morphology.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/jemt.1060010208
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    A microcomputer program in “BASIC” for the accurate determination of the height of small particles (1984)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 1 (1984), S. 399-404 
    Details
    ISSN: 0741-0581
    Keywords: Particle size ; Electron microscopy ; Microcomputer programs ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A formula is derived to enable the calculation of the true height of an object, such as a shadowed latex bead, from electron micrographs. Knowing only the angle of shadowing and the length of the evaporated shadow, and by substituting these values in the derived formula, a microcomputer may be programmed to carry out the necessary computations. An example of such a microcomputer program is given. The correct determination of the height of particles by electron microscopy using the shadowing technique is one of the most accurate methods available for the determination of small particle height.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/jemt.1060010408
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  • 97
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    Ultrathin formvar support films for transmission electron microscopy (1985)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985), S. 35-43 
    Details
    ISSN: 0741-0581
    Keywords: Support films ; Formvar ; Electron microscopy ; Smoothness ; Thickness ; Stability ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: We have found that ultrathin Formvar films are easily and reliably made at an air-water interface by the drop method. By varying the concentration of Formvar in the drop, films of different characteristics can be obtained. Concentrations of 0.25-0.4% in ethylene dichloride produce extremely flat, ultrathin, and stable films that are especially suited for shadowed and negatively stained preparations. Low concentrations (≤ 0.1%) produce nets consisting of many tiny holes which, after carbon stabilization, are ideal for supporting high-resolution samples. Above 0.5%, films made by the drop method develop bubbles, and this bubble defect makes them unsuitable for section support.For section support, Formvar films made by the stripping method off mica are far superior to those made off glass. The films are more uniform in surface contour and thickness. They are less readily attacked by alcohols. Consequently, they are more resistant to staining procedures involving organic solvents and continue to be strong and uniform for section support.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/jemt.1060020105
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  • 98
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    Electron crystal structure analysis of small organic molecules (1985)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 2 (1985), S. 89-128 
    Details
    ISSN: 0741-0581
    Keywords: Crystal structure analysis ; Electron diffraction ; Organic crystals ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Electron crystallography of small organic molecules, i.e., electron diffraction crystal structure analysis, has been long recognized to possess definite advantages over neutron and x-ray diffraction techniques for the investigation of microcrystalline preparations. Quantitative application of the technique to real structural problems, on the other hand, had been hindered initially by an inadequate theoretical model. Yet, as demonstrated in this review of the methodology, the adequate recognition of limiting factors due to n-beam dynamical scattering and crystal deformation permits design of optimal diffraction experiments which yield intensity data suitable for ab initio structure analysis. Representative crystallographic analyses discussed here underscore the utility of this technique as a probe of organic molecular structure at atomic resolution.
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    URL: http://dx.doi.org/10.1002/jemt.1060020203
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  • 99
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    Quantitative analysis of synapse structure with a semiautomatic interactive computer system: A study on identified pyramidal tract neurons in the sensory-motor cortex of cat (1986)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 4 (1986), S. 241-256 
    Details
    ISSN: 0741-0581
    Keywords: Morphometry ; Immunocytochemistry ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Pyramidal tract (Pt) neurons in the sensory-motor cortex of cat were labeled by injection of HRP into the spinal cord. Ultrastructural and quantitative analysis of the synaptic covering of their soma and apical dendrite (up to 100 μm from soma) was undertaken. We intercalated a visual-manual treatment between composite electron micrographs and a fully automated computer system and developed specific programs for evaluation of the morphometric data. Programs are included. A total of 412 synaptic boutons were examined that were found in contact with large Pt neurons. The mean linear percentage of the surface area covered by boutons was 26.2 ± 8.4% and the mean contacting length and cross-sectional area of the bouton profiles were 1.28 ± 0.58 μm and 0.89 ± 0.59 μm2, respectively. All types of boutons with active zones accounted for 41.2% of the total. The distribution of two types of bouton (S- and F-type boutons, showing asymmetric and symmetric contacts, respectively) was examined quantitatively. The mean proportion of F-type boutons was 89.1% with a soma and S-type boutons contacting apical dendrites was 10.9%. In addition, GABAergic boutons were identified with the soma by immunocytochemistry with antibodies against glutamic acid decarboxylase. They formed symmetric synaptic contacts with the Pt cells that were identical to those formed by F-type boutons. The quantitative analysis revealed that synaptic clefts are narrower and synaptic vesicles are smaller in symmetric F-type boutons than in S-type boutons forming asymmetric contacts. These data establish that at least three parameters (postsynaptic density, synaptic cleft, and size of vesicles) can be utilized singly or in combination to identify GABAergic inhibitory synapses in neocortex.
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    URL: http://dx.doi.org/10.1002/jemt.1060040303
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  • 100
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    Dynamic hydration effects in an electron microscope cold stage (1988)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 8 (1988), S. 349-354 
    Details
    ISSN: 0741-0581
    Keywords: Electron microscopy ; Mass loss ; Ice ; Radiation damage ; Collodion films ; Electron energy loss spectrometer ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Water can be a substantial proportion of the residual gas in modern electron microscopes even when frozen hydrated specimens are not used. During measurements of the mass thickness of thin collodion film specimens at low temperatures, it was found that a volatile surface layer (condensed water) modified the apparent rate of mass loss induced by radiation exposure. Mass loss can be enhanced by the presence of water (specimen “etching”), or mass loss can be masked by the dynamic adsorption of water to the specimen surface. The microscope or the grid can be a secondary source of the water; even with cold anticontaminator plates in the vicinity of the specimen, water can be desorbed by x-rays or backscattered electrons. In one typical situation, the mass loss rate appears reduced (due to water adsorption), but the ultimate damage is greater (due to etching). These results illustrate that care must be taken in interpreting mass thickness measurements made in the presence of water and that the lowest stage temperature does not necessarily produce the best observation conditions for all specimens.
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    URL: http://dx.doi.org/10.1002/jemt.1060080403
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