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  • Electron microscopy  (73)
  • Springer  (73)
  • American Physical Society
  • Annual Reviews
  • Springer Nature
  • 1980-1984  (73)
  • 1960-1964
  • 1935-1939
  • 1982  (27)
  • 1980  (46)
Collection
Keywords
Publisher
  • Springer  (73)
  • American Physical Society
  • Annual Reviews
  • Springer Nature
  • Wiley-Blackwell  (1)
Years
  • 1980-1984  (73)
  • 1960-1964
  • 1935-1939
Year
  • 1
    Electronic Resource
    Electronic Resource
    Heat of fusion and lamellar structure of polyethylene single crystal mats (1982)
    Springer
    Colloid & polymer science 260 (1982), S. 564-569 
    Details
    ISSN: 1435-1536
    Keywords: lin. Polyethylene ; Single crystals ; Heat of Fusion ; DSC ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Recently published results for solution crystallized PE single crystals have shown, that the experimental heat of fusionΔH * is higher, if the solvent is exchanged to silicon oil (oil suspension samples) as compared with dried mats. This has been interpreted by the collapse of the original hollow pyramids during drying, inducing lateral defects within the lamellae. The present investigation does not confirm this unexpected result.ΔH * of dried mats (T c 66 to 91 °C) and of the corresponding oil suspension samples agree within the rather small limits of experimental error. The crystallinities as derived fromΔH *, density or WAXS are in excellent agreement. SEM micrographs of cold fractured dried mats show their spongy macromorphology, but TEM micrographs of stained ultra-thin sections reveal the lamellar morphology of the walls, consisting of curved lamellae and stacked hollow pyramides. If a dried mat is sintered at room temperature, a dense transparent film is obtained with a rather regular stacked morphology of large flat lamellae.ΔH * of these films agrees with that of the original mat.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01422587
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  • 2
    Electronic Resource
    Electronic Resource
    Ultrastructural evidence for inhibition of chitin synthesis by nikkomycin (1982)
    Springer
    Development genes and evolution 191 (1982), S. 205-207 
    Details
    ISSN: 1432-041X
    Keywords: Chitin inhibition ; Nikkomycin ; Cuticle ; Electron microscopy ; Epilachna varivestis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The nucleoside antibiotic nikkomycin has proved to be an effective inhibitor of chitin synthesis in the Mexican bean beetleEpilachna varivestis. Ultrastructural investigations show defects in the procuticular area after nikkomycin application which suggest the complete absence of chitin. A cuticle like this is inflexible and too brittle to satisfy its normal function as an exoskeleton. The individuals are not able to free themselves from the exuvia and finally die. Therefore nikkomycin seems to be a potential insecticide with high specifity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848337
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  • 3
    Electronic Resource
    Electronic Resource
    A scanning electron microscopic investigation of in vitro osteogenesis (1980)
    Springer
    Calcified tissue international 30 (1980), S. 43-50 
    Details
    ISSN: 1432-0827
    Keywords: Osteogenesis ; In vitro ; Electron microscopy ; Mineralization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Chick limb mesenchymal cells differentiate into muscle, cartilage, fibrous, and bone tissue. Previous reports show that when stage 24 limb mesenchymal cells are cultured in vitro, chondrocytes, myocytes, fibrocytes, and osteoblasts can be identified on the basis of morphological and biochemical parameters. The study reported here demonstrates that phenotypic expression in culture seems to be dependent on the initial plating density, Scanning electron microscopic observations indicate that when stage 24 limb mesenchymal cells are initially seeded at high densities (5 × 106 cells per 35 mm culture dish), mounds of cells appear in culture. These mounds represent cartilage nodules composed of a fine fibrous matrix and chondrocytes, surrounded by a loose fibrous connective tissue matrix. Cultures initially plated at intermediate densities (2.0–2.5 × 106 cells/35 mm culture dish) produce a flattened layer of fibrocytes overlying a matrix of collagen fibers and calcium phosphate deposits as determined by electron-microprobe analysis; these observations are indicative of osteoblast expression. Cells seeded at this intermediate density appear larger and possess greater surface area than cells seeded at high density. It is suggested that conditions that permit such increased cell surface area coupled with a relative compaction due to cell crowding may provide conditions permissive for osteogenesis. Based on morphological criteria, it appears that chick limb mesenchymal cell osteogenesis in vitro is not associated with chondrogenesis but represents a separate route of phenotypic expression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408605
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  • 4
    Electronic Resource
    Electronic Resource
    Fine structure of fetal rat calvarium; provisional identification of preosteoclasts (1980)
    Springer
    Calcified tissue international 31 (1980), S. 21-28 
    Details
    ISSN: 1432-0827
    Keywords: Rat ; Calvarium ; Electron microscopy ; Preosteoclasts ; Osteoclasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary This is a study of the fine structure of cells of the 20-day fetal rat calvarium. Special attention is given to identifying and characterizing preosteoclasts. These cells are relatively common and located largely, but not exclusively, at the endocranial bone surface. The preosteoclasts are characterized by abundant mitochondria, an incomplete perinuclear Golgi apparatus, and variable-shaped dense granules. The dense granules are unique in appearance in that they contain an internal dense matrix surrounded by a clear halo. Most granules are circular in shape but some are elongate or tubular in form. Granules with identical appearance are observed in osteoclasts. The preosteoclasts are mononucleate, or occasionally binucleate. It is suggested that because preosteoclasts are morphologically distinctive and relatively abundant, it should be feasible to separate these cells from a heterogeneous cell isolate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02407163
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  • 5
    Electronic Resource
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    Effects of demineralization in an ethanolic solution of triethylammonium EDTA on solubility of bone matrix components and on ultrastructural preservation (1980)
    Springer
    Calcified tissue international 32 (1980), S. 175-179 
    Details
    ISSN: 1432-0827
    Keywords: Decalcification ; Electron microscopy ; Bone matrix ; Bone glycoproteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary A solution of triethylammonium EDTA in 80% ethanol was evaluated as a demineralizing reagent for bone in comparison with aqueous solutions of EDTA. Biochemical analysis and acrylamide gel electrophoresis of extracts of finely powdered bovine bone showed that most of the macromolecular components of the organic matrix extractable in aqueous EDTA were retained when the triethylammonium EDTA reagent was used. Ultrastructural examination of chick tibias decalcified with the reagents showed a better preservation of cellular morphology, especially the membranous components, and more uniformly distributed ground substance, though slightly less in quantity, when the aqueous reagent was used. Use of the two reagents appears to be complementary, the alkylammonium reagent being more appropriate for use in studies of the organic matrix of bone, including immunohistochemical studies of bone glycoproteins. The aqueous reagent is more appropriate for use in studies of cellular ultrastructure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408537
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  • 6
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    The ultrastructure of cell wall formation and of gamma particles during encystment of Allomyces macrogynus zoospores (1980)
    Springer
    Archives of microbiology 128 (1980), S. 179-189 
    Details
    ISSN: 1432-072X
    Keywords: Allomyces ; Zoospores ; Cell wall ; Chitin ; Gamma particle ; Encystment ; Electron microscopy ; Calcofluor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Structural changes during cell wall formation by populations of semisynchronously germinating zoospores were studied in the water mold Allomyces macrogynus. Fluorescence microscopy using Calcofluor white ST (which binds to β-1,4-linked glycans) demonstrated that Calcofluor-specific material was deposited around most cells between 2–10 min after the induction of encystment (beginning when a wall-less zoospore retracts its flagellum and rounds up). During the first 15 min of encystment there was a progressive increase in fluorescence intensity. Ultrastructural analysis of encysting cells showed that within 2–10 min after the induction of encystment small vesicles 35–70 nm diameter were present near the spore surface, and some were in the process of fusing with the plasma membrane. The fusion of vesicles with the zoospore membrane was concomitant with the appearance of electron-opaque fibrillar material outside the plasma membrane. Vesicles similar to those near the spore surface were found within the gamma (γ) particles of encysting cells. These particles had a crystalline inclusion within the electron-opaque matrix. During the period of initial cyst cell wall formation numerous vesicles appeared to arise at the crystal-matrix interface. Approximately 15–20 min was required for the cell wall to be formed. We suggest that the initial response of the zoospore to induction of encystment is the formation of a cell wall mediated by the fusion of cytoplasmic vesicles with the plasma membrane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00406156
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  • 7
    Electronic Resource
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    Evidence for supercoiling in the DNA of bacteriophage heads (1980)
    Springer
    Archives of microbiology 126 (1980), S. 277-283 
    Details
    ISSN: 1432-072X
    Keywords: Bacteriophage ; Myxococcus ; λ ; Superooiled DNA ; Cross-linking ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract DNA was partially released from the heads of myxococcus phages and also coliphage λ and examined by electron microscopy by a modification of the Kleinschmidt technique, in which water was used as hypophase. DNA emerged from the heads in patterns suggestive of newly relaxed supercoils. The unreleased DNA appeared to occupy discrete regions in the head. Some closed circles were released from λ heads. When NaCl solution was used as hypophase, the DNA was observed either released from the tail or from the head, in the latter case, supercoiled regions were observed. When NH4OAc solution was used as hypophase, tightly wound structures were released from λ heads; these fields also contained supercoiled circles. The presence of constrained supercoiled domains in newly released phage DNA was confirmed by observing the effects of ethidium bromide on its conformation. Treatment of phage with nitrogen mustard, a bifunctional alkylating agent, preserved supercoiled domains, even when the phage were lysed over water as hypophase. Further experiments suggested that phage inactivation by nitrogen mustard is largely due to restraint of the supercoiled, native, tertiary structure and that DNA-protein cross-linking may be involved in this reaction. The implications of these findings for the conformation of phage DNA in vivo are discussed and a new model for the winding of DNA in phage heads is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00409932
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  • 8
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    Comparative studies onChlorella cell walls: Induction of protoplast formation (1982)
    Springer
    Archives of microbiology 132 (1982), S. 10-13 
    Details
    ISSN: 1432-072X
    Keywords: Calcofluor White ; Cell wall structure ; Chlorella ; Electron microscopy ; Protoplast ; Ruthenium Red
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Among 12 strains ofChlorella ellipsoidea, C. vulgaris, andC. saccharophila tested, 4 strains (1,C. ellpsoidea; 2,C. vulgaris; 1,C. saccharophila) formed osmotically labile protoplasts after treatment with mixtures of polysaccharide degrading enzymes. The relationship between enzymatical digestibility and structure or composition ofChlorella cell walls were studied by electron microscopy and staining techniques with some specific dyes. The cell wall structures of the 12Chlorella strains were grouped into three types: (1) with a trilaminar outer layer, (2) with a thin outer monolayer, and (3) without an outer layer. Protoplasts were formed only from the strains with a cell wall of Type 2. In the strains with a cell wall of Type 1, the outer layer protected the inner major microfibrillar layer against enzymatic digestion. The cell wall of Type 3 was totally resistant to the enzymes; the chemical composition of the cell wall would be somewhat different from that of other types.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00690809
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  • 9
    Electronic Resource
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    Immunoferritin labeling of respiratory nitrate reductase in membrane vesicles of Bacillus licheniformis and Klebsiella aerogenes (1980)
    Springer
    Archives of microbiology 127 (1980), S. 39-46 
    Details
    ISSN: 1432-072X
    Keywords: Immunoferritin labeling ; Electron microscopy ; Membrane vesicles ; Nitrate reductase ; Bacillus licheniformis ; Klebsiella aerogenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The indirect immunoferritin labeling method was used to localize the membrane-bound respiratory nitrate reductase in membrane vesicles and protoplasts or spheroplasts of Bacillus licheniformis and Klebsiella aerogenes, respectively. For a comparison of the labeling of the various vesicle preparations, which differed not only in size but also in the percentage of inside-out orientation, a quantification of the results was needed to circumvent the problem of non-specifically bound ferritin. From the results the sidedness of the nitrate reductase in the cytoplasmic membrane of the abovementioned bacteria was determined as being cytoplasmic in B. licheniformis and as transmembranous in K. aerogenes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00414353
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  • 10
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    Chemical composition and ultrastructure of cellular and extracellular Moraxella glucidolytica lipopolysaccharides (1980)
    Springer
    Archives of microbiology 128 (1980), S. 12-18 
    Details
    ISSN: 1432-072X
    Keywords: Moraxella glucidolytica ; Electron microscopy ; Lipopolysaccharide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A cellular (LPS I) and extracellular (LPS II) lipopolysaccharide were isolated from Moraxella glucidolytica cells grown on ethanol and from the culture fluid, respectively. Both LPS were toxic when injected to mice and chick embryos. These LPS contained glucose, galactose, glucosamine, galactosamine, 2-keto-3-deoxyoctonate and lipids. By permethylation studies, glucose was found to be linked (1→6) and (1→3) in LPS I and only (1→6) in LPS II. Galactose was the terminal non-reducing sugar. Branching occurred at positions 3 and 4 of galactose residues. LPS I was rich in α- and β-hydroxylauric and α-hydroxymyristic acids and LPS II contained mainly stearic and α-hydroxymyristic acids. LPS I was detoxified by mild acid and alkaline treatments. It was also dissociated by sodium deoxycholate and chromatographed on Sephadex G-75. The main fraction was reassociated by removing the surfactant by dialysis. The morphology of LPS I and LPS II was examined by electron microscopy. LPS I (original and reassociated fractions) consisted exclusively of ribbons while LPS II contained ribbons and vesicles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00422299
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  • 11
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    Ultrastructure of Ascodichaena rugosa on beech bark (1980)
    Springer
    Archives of microbiology 126 (1980), S. 87-95 
    Details
    ISSN: 1432-072X
    Keywords: Ascodichaena ; Beech bark ; Electron microscopy ; Host-fungus relationship
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ascodichaena rugosa Butin is a corkinhabiting fungus, found frequently on the bark of Fagus sylvatica L. The hyphae of the fungus are distributed solely in the phellem cells, stopping their growth in the last-formed cork cell layer. The cell to cell invasion is effected by penetration hyphae, causing no extensive dissolution of the cork wall. Electron microscopical observations revealed fine structural details of the fruit bodies and of the intracellular hyphae. Of special interest were the finger-like hyaline hyphae in the last-formed layer of cork cells, which are interpreted as haustoria on the basis of the fine structure both of hyphae and host cells. This situation is considered as reflecting a parasitic relationship of Ascodichaena to beech bark. The activity of the fungus led also to the increased production of cork cells, perhaps related to the nutrient supply of the fungus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00421896
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  • 12
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    Thylakoid centers: Structures associated with the cyanobacterial photosynthetic membrane system (1982)
    Springer
    Archives of microbiology 133 (1982), S. 97-99 
    Details
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Thylakoid centers ; Photosynthetic membranes/thylakoids ; Membranes ; Membrane biogenesis ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An ultrastructural study of four cyanobacteria (Anabaena cylindrica, Dermocarpa violaceae, Gleocapsa alpicola, Pleurocapsa minor) indicates the presence of previously undescribed thylakoid centers from which photosynthetic membranes (thylakoids) radiate. These peripherally located thylakoid centers are cylinders 30 nm wide by 320 nm long, consisting of globular subunits oriented in nonparallel stacked arrays. Thylakoids are attached to the outer surface of the cylinder along its longitudinal axis. Thylakoid centers appear to be functionally significant due to their structure, location and thylakoid association.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00413518
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  • 13
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    Cell wall degradation ofStaphylococcus aureus by lysozyme (1982)
    Springer
    Archives of microbiology 131 (1982), S. 116-123 
    Details
    ISSN: 1432-072X
    Keywords: Cell wall ; Wall degradation ; Lysozyme ; Autolysines ; Electron microscopy ; Staphylococcus aureus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In contrast to former findings lysozyme was able to attack the cell walls ofStaphylococcus aureus under acid conditions. However, experiments with14C-labelled cell walls and ribonuclease indicated that, under these conditions, lysozyme acted less as an muralytic enzyme but more as an activator of pre-existing autolytic wall enzymes. Electron microscopic studies showed that under these acid conditions the cell walls were degraded by a new mechanism (i.e. “attack from the inside”). This attack on the cell wall started asymmetrically within the region of the cross wall and induced the formation of periodically arranged lytic sites between the cytoplasmic membrane and the cell wall proper. Subsequently, a gap between the cell wall and the cytoplasmic membrane resulted and large cell wall segments became detached and suspended in the medium. The sequence of lytic events corresponded to processes known to take place during wall regeneration and wall formation. In the final stage of lysozyme action at pH 5 no cell debris but “stabilized protoplasts” were to be seen without detectable alterations of the primary shape of the cells. At the same time long extended ribbon-like structures appeared outside the bacteria. The origin as well as the chemical nature of this material is discussed. Furthermore, immunological implications are considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01053992
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  • 14
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    Phagocytosis of spermatozoa by the ovum of the domestic fowl, Gallus gallus at the time of fertilization (1980)
    Springer
    Cell & tissue research 206 (1980), S. 55-63 
    Details
    ISSN: 1432-0878
    Keywords: Phagocytosis ; Spermatozoa ; Ovum ; Fertilization ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Spermatozoa with intact acrosomes, as well as those coming into contact with the ovum at a smaller angle, and morphologically abnormal spermatozoa reach the plasma membrane of the ovum via an extensively dissolved zone of the inner layer of the vitelline membrane. This zone is assumed to be formed by overlapping of two or more tunnels formed by spermatozoa that had previously come into contact with the ovum. When a spermatozoon comes into contact with the plasma membrane of the ovum, many cytoplasmic processes extend outwards and cover it. Thereafter, the plasma membranes of the processes fuse, thereby phagocytizing the spermatozoon. It is assumed that the phagocytized spermatozoa cannot undergo transformation into male pronuclei and that they degenerate soon after phagocytosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233607
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  • 15
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    Ca++-induced structural changes in photoreceptor microvilli of diptera (1980)
    Springer
    Cell & tissue research 206 (1980), S. 225-232 
    Details
    ISSN: 1432-0878
    Keywords: Compound eye ; Photoreceptor membrane ; Electron microscopy ; Calcium-induced changes ; Artefacts ; Diptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary When the compound eyes of the fly Lucilia are fixed for electron microscopy with glutaraldehyde in common buffer solutions, artefactual whorls are liable to be formed from the photoreceptor microvilli. The whorls result from two factors: (i) a prolonged time interval prior to osmication, such as the “overnight” primary fixation or wash at 4° C commonly used in studies of compound eyes; (ii) as little as 1–2 mM Ca++ in the primary fixative and wash solutions. Osmication after short (1 h) glutaraldehyde fixation at 4° C, or omission of Ca++ and addition of 2 mM EGTA, prevent whorl-formation. In the tipulid fly Ptilogyna, similar artefacts are produced, but are confined to the distal zone of the microvilli that sheds during turnover.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00232766
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  • 16
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    Scanning and transmission electron microscopic observations of the cloacal epithelia of the domestic fowl (1980)
    Springer
    Cell & tissue research 211 (1980), S. 83-93 
    Details
    ISSN: 1432-0878
    Keywords: Epithelium ; Cloaca ; Electron microscopy ; Hen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The epithela of the three divisions (coprodaeum, urodaeum, proctodaeum) of the cloaca of the hen, and of the excretory ducts (colon, ureter, vagina) which join the divisions, are described using light microscopy, and scanning and transmission electron microscopy. Each region of the cloaca has its typical epithelium. Special attention is focussed in this study on the boundaries between the different epithelia. The coprodaeal epithelium does not differ considerably from that of the colon; a transitional zone is not visible. Distinct border zones, however, are observed between the other regions (ureter — urodaeum; vagina — urodaeum and proctodaeum; urodaeum-proctodaeum; proctodaeum — cutis). Although the vaginal opening is generally thought to lie in the urodaeum, our investigations show that at the vaginal opening into the cloaca the ciliated epithelium changes, on one border to a secretory epithelium characteristic of the urodaeum and on the other border to that characteristic of the proctodaeum. These observations are discussed in relation to functional aspects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233725
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  • 17
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    Ultrastructural alterations of the pancreatic D cell in the domestic fowl following vagotomy (1980)
    Springer
    Cell & tissue research 211 (1980), S. 171-174 
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    ISSN: 1432-0878
    Keywords: Pancreatic D cell ; Neural control ; Vagotomy ; Electron microscopy ; Fowl
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In an attempt to determine the neural control of pancreatic D cells, the pancreatic islets of the domestic fowl were examined electron microscopically from 1 to 28 days after abdominal vagotomy. Exocytotic release of many secretory granules from D cells occurred one day after vagotomy. Rough endoplasmic reticulum developed and formed an arrangement of concentric whorls in the cytoplasm of D cells after axotomy. The altered D cells were also characterized by the occurrence of many peculiar dense bodies in the apical cytoplasm at all time periods studied. These bodies varied in shape and size, containing several round vesicles. The D cells were extensively depleted of granules after the longer time periods following vagotomy. The present results provide new morphological evidence for the vagus-nerve control of D cells, which may regulate the activity of islet cells.
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    URL: http://dx.doi.org/10.1007/BF00233732
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  • 18
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    Fetal hypothalamic transplants in the third ventricle of the adult rat brain (1980)
    Springer
    Cell & tissue research 211 (1980), S. 191-206 
    Details
    ISSN: 1432-0878
    Keywords: Hypothalamus ; Transplants ; Vasopressin ; Median eminence ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Blocks of anterior hypothalamus were transplanted from 19 day-old fetuses of Wistar/Lewis rats into the third ventricle of adult male Brattleboro rats. Physiological changes in graft recipients and in sham-operated animals were monitored daily. Twenty days after surgery, the graft recipients and shamoperated animals were killed and their brains examined by correlative scanning and transmission electron microscopy. Host animals that exhibited both decreased polydipsia and increased urine concentration were found to have viable grafts within the third ventricle. The observed physiological changes suggested that synthesis and release of vasopressin occurred in the transplanted neurons. Grafts were well vascularized by vessels arising from the host hypothalamus. Neurons, with perikarya ranging from 8 to 30 μm in diameter, glial cells, and neurites were located throughout the transplants. A neurohemal contact zone, similar to that normally seen in the median eminence, could not be demonstrated in the grafts. The absence of complete glial and ependymal barriers indicates a relatively close association between cells in the transplants and the cerebrospinal fluid. A large increase in supraependymal neurons and their processes, including an eruption of neurons through the floor of the third ventricle in one animal, was observed in graft recipients but not in shamoperated animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236442
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  • 19
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    Fine structure of ependymal cysts in and around the area postrema of the rat (1980)
    Springer
    Cell & tissue research 206 (1980), S. 303-318 
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    ISSN: 1432-0878
    Keywords: Area postrema, rat ; Ependyma ; Cyst ; Circumventricular organs ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Peculiar cells forming cysts were observed in the area postrema and sometimes also in the choroid plexus and the tela chorioidea near the area postrema, and were studied in detail by electron microscopy. The cytological features of the cyst cell and its junctional relationship to neighboring cells imply that cyst cells are derived from ependymal and choroid epithelial cells. The cyst cells usually contact directly the perivascular spaces of postremal, choroidal or pial capillaries, where the cytoplasm is often considerably attenuated. The cystic lumen is commonly filled with a flocculent material. The limiting membrane of the cystic lumen, which frequently bears cilia and microvilli, has the same thickness as the surface cell membrane. In many cases, the cyst is surrounded by the cytoplasm of a single cell. In some cases, however, two cells participate in the formation of the cyst, although one is only a slender process and joined by a zonula occludens with the main cyst cell. Horseradish peroxidase (HRP) injected into the cerebrospinal fluid (CSF) space failed to enter the cystic lumen. A possible significance of the cyst in relation to the CSF and blood circulation was considered.
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    URL: http://dx.doi.org/10.1007/BF00232774
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  • 20
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    Incorporation of 3H-oleic acid by the proximal convoluted tubule cells of the chick (Gallus domesticus) (1980)
    Springer
    Cell & tissue research 210 (1980), S. 447-459 
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    ISSN: 1432-0878
    Keywords: Lipid ; Kidney tubules, proximal ; Autoradiography ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Lipid metabolism in the cells of the renal proximal convoluted tubules (PCT) was investigated in healthy fowls and in fowls with the Fatty Liver and Kidney Syndrome (FLKS). The tissue was fixed at 10–25 min intervals after intravenous injection of 3H-oleic acid. The distribution of autoradiographic grains was analysed by the “circle method”. In normal cells most of the silver grains were associated with the cytoplasmic organelles. Lipid droplets and Golgi elements had the highest specific activity relative to the nuclear activity, which was little above background level. Lysosome-like bodies and mitochondria had lower values. In the cells of the FLKS-affected birds a large proportion of the grains was located over the lipid droplets, which are abundant in this condition. The specific activity of the cytoplasmic organelles was barely 2-fold higher than the nuclear activity. The results suggest that there is a diminished incorporation of esterified fatty acids by the organelles of these cells and that the excess is transferred to the lipid droplets. The identity of low electron density particles observed in the PCT cells of severely affected birds is discussed.
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    URL: http://dx.doi.org/10.1007/BF00220201
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    Gut hormones in Salamandra salamandra (1980)
    Springer
    Cell & tissue research 211 (1980), S. 331-343 
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    ISSN: 1432-0878
    Keywords: Gut hormones ; Endocrine cells ; Electron microscopy ; Immunocytochemistry ; Peptidergic innervation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Histological, cytochemical and immunocytochemical methods were used in light and electron microscopical studies to demonstrate the presence of a neuroendocrine system in the gut of the urodele, Salamandra salamandra. Cytochemical stains capable of detecting peptide-producing endocrine cells demonstrate cells reacting with Masson's silver (argentaffin) method, Grimelius' argyrophil silver method, masked metachromasia method and the lead haematoxylin stain. Using antisera raised to a variety of mammalian gut peptides, cells containing bombesin-, gastrin-, somatostatin-, substance P- and glucagon-like immunoreactivity were identified; vasoactive intestinal polypeptide- and substance P-like immunoreactivities were found in nerve fibres in the submucous and myenteric plexus. No immunoreactivity was detected for motilin, gastric inhibitory polypeptide, cholecystokinin or secretin. The ultrastructure of the immunoreactive cells and nerves was revealed by the semithin/thin method. All the cells identified contained numerous electrondense secretory granules, which varied in their chracteristic morphological structure from one cell type to another. The evidence collected in this study indicates that a complex neuroendocrine system regulating gut function is present in this amphibian and may have developed prior to the emergence of the phylum.
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    URL: http://dx.doi.org/10.1007/BF00236453
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    Monoaminergic neurons of the mudpuppy retina (1980)
    Springer
    Cell & tissue research 210 (1980), S. 269-282 
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    ISSN: 1432-0878
    Keywords: Monoaminergic neurons ; Retina ; Amacrine cells ; Neurotoxins ; Mudpuppy, Necturus maculosus ; Neurotransmitters ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The mudpuppy retina was investigated with the histofluorescence method of Falck and Hillarp in normal animals and in animals injected intraocularly with α-methylnoradrenaline, 5,6-dihydroxytryptamine, or a combination of the two drugs. Catecholaminergic amacrine cells were found to form a thin layer of terminals at the border between the inner nuclear and the inner plexiform layers. Catecholaminergic interplexiform cells were not found. Indoleamine-accumulating amacrine cells were also observed. They are fifteen to twenty times more numerous than the catecholaminergic cells, and their terminals occur diffusely throughout the inner plexiform layer. In a number of eyes the majority of the indoleamine-accumulating terminals were eliminated with intraocular injections of the neurotoxin, 5,7-dihydroxytryptamine, but the reproducibility of this effect was not consistent. Intravitreal injections of 5,6-dihydroxytryptamine were used to label both types of neurons for electron microscopy. They were found to make conventional type synapses on amacrine cells and, less frequently, on bipolar cells.
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    Merkel cells and nerve endings in the labial epidermis of a lizard (1980)
    Springer
    Cell & tissue research 210 (1980), S. 353-357 
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    ISSN: 1432-0878
    Keywords: Merkel cells (reptiles) ; Epidermis ; Lizard ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Examination of the labial epidermis of the lizard Lacerta sicula revealed cells displaying all features of Merkel cells. These cells are located in the stratum basale of epidermal pegs and are arranged in clusters.
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    URL: http://dx.doi.org/10.1007/BF00237623
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    Ultrastructural changes in Paneth cells during hibernation in the ground squirrel Spermophilm lateralis (1980)
    Springer
    Cell & tissue research 211 (1980), S. 293-301 
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    ISSN: 1432-0878
    Keywords: Paneth cell ; Hibernation ; Intestine ; Hypothermia ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of Paneth cells from jejuno-ileal segments of the small intestine of the ground squirrel, S. lateralis, was examined under normal euthermic conditions and during the profoundly depressed metabolic conditions of natural hibernation. Paneth cells obtained from hibernating animals gave evidence of markedly reduced activity when compared to Paneth cells from euthermic animals. In hibernating animals, the nuclei were smaller, with less prominent nucleoli and with an increased proportion of heterochromatin. In hibernating animals, the rough endoplasmic reticulum was fragmentary and poorly organized, in contrast to the typical arrangement of concentric lamellae seen in euthermic animals. Although the total number of ribosomes was decreased in hibernating animals, there were proportionally more free ribosomes than in euthermic animals. Paneth cells from hibernating animals also contained a greater number of apical secretory granules which were smaller and more variable in electron density than granules from control animals. These ultrastructural features indicate that during hibernation the Paneth cell is relatively quiescent.
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    Effect of testosterone on the female hamster harderian gland pigmentation and ultrastructure (1980)
    Springer
    Cell & tissue research 207 (1980), S. 511-517 
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    ISSN: 1432-0878
    Keywords: Female hamster ; Harderian gland ; Testosterone ; Tubular clusters ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Distinct differences occur in the pigmentation and ultrastructural features of the Harderian glands in male and female hamsters. The results of a study on the effect of testosterone on the fine structure of the female Harderian glands are presented here. Glands from three groups of hamsters were examined at intervals up to 49 days: (1) testosterone injected, receiving 2mg testosterone propionate in 0.1 ml sesame oil per day; (2) sham-injected, receiving 0.1 ml sesame oil per day; (3) untreated controls. Testosterone injections caused a reduction in the number of dark-brown pigment granules in the acinar cells starting on the 6th day, whereas clusters of tubules, typical of adult male glands, appeared on the 4th day and increased in number thereafter. Lamellar structures, normally present in the female gland, decreased in testosterone treated specimens. These changes reversed after cessation of testosterone treatment. It is concluded that exogenous testosterone administered to female hamsters modifies the pigmentation and ultrastructure of their Harderian glands towards the male type and that this is a reversable phenomenon. There also appears to be an inverse relationship between the presence of tubular clusters in the acinar cells, and the degree of pigmentation.
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    URL: http://dx.doi.org/10.1007/BF00224624
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    Microtubules, dendritic spines and spine apparatuses (1980)
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    Cell & tissue research 208 (1980), S. 171-181 
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    ISSN: 1432-0878
    Keywords: Microtubules ; Dendritic spine apparatus ; Synapse ; Development ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using techniques for enhanced microtubular preservation, including albumin pretreatment (Gray, 1975), occipital cortex of rats was studied electron microscopically at various ages of development. A close structural relationship was seen between microtubules, sacs of SER and the postsynaptic “thickening” in primordial spines and with the dense “plate” material of spine apparatuses. Stereoscopic preparations in addition show a more complicated substructure than previously described for the “plate”. Microtubules may contribute to the formation of the “plate” of the spine apparatus which in turn is associated with the postsynaptic “thickening” of the mature spine. Possible functional correlates are discussed.
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    Survival of satellite cells following exposure to the local anesthetic bupivacaine (Marcaine) (1980)
    Springer
    Cell & tissue research 209 (1980), S. 131-135 
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    ISSN: 1432-0878
    Keywords: Skeletal muscle ; Bupivacaine ; Degeneration ; Satellite cells ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Rat lumbrical muscles were incubated in a concentration of 10-2 M bupivacaine for 5 or 15 min and examined after further incubation in the absence of the drug for periods totalling 1, 2, and 3h. Electron microscopy showed that muscle fibers and their component organelles and myonuclei underwent a series of irreversible degenerative changes. However, satellite cells retained their normal morphology under similar conditions. It is concluded that satellite cells are responsible for the rapid regeneration of muscles that follows degeneration induced by bupivacaine. The role of satellite cells in muscle regeneration is discussed.
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    URL: http://dx.doi.org/10.1007/BF00219929
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    Ultrastructural changes in the urophysis of Mollienesia sphenops following adaptation to seawater (1980)
    Springer
    Cell & tissue research 207 (1980), S. 135-142 
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    ISSN: 1432-0878
    Keywords: Caudal neurosecretory system ; Poeciliidae ; Electron microscopy ; Salinity changes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The urophysis or neurohemal contact site of the caudal neurosecretory system of Mollienesia sphenops, the black molly, was studied in animals adapted to an artificial seawater environment. This species of fish was chosen for these studies because of its known ability to osmoregulate and its adaptability to the laboratory aquarium. The urophysis of freshwater acclimated mollys contained an abundance of neurosecretory granules. However, in fish subjected to a seawater environment for one week the number of neurosecretory granules was significantly decreased. In addition, there was an increase in blood cell infiltration of the urophysis.
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    Studies on the juxtaglomerular apparatus VI. Sympathetic innervation, catecholamines and the renin-angiotensin-system in rats and tree-shrews (Tupaia belangeri) (1980)
    Springer
    Cell & tissue research 212 (1980), S. 375-382 
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    ISSN: 1432-0878
    Keywords: Juxtaglomerular apparatus ; Sympathetic innervation ; Renin-angiotensin system ; Electron microscopy ; Fluorescence microscopy ; Tupaia belangeri ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary It has previously been reported that the primitive primate Tupaia belangeri develops a renal failure when exposed to psychosocial stress. In order to learn if this high susceptibility to stress of the Tupaia kidney can be correlated with morphological and functional parameters of the Juxtaglomerular apparatus (JGA) and the renin-angiotensin system, comparative experiments were performed on Tupaia and rat. Our results reveal an outstandingly high potency of the JGA and the renin-angiotensin system in Tupaia as evident from the following findings: The Tupaia JGA contains a great number of epithelioid cells abounding in renin granules (electron microscopy). The renin content of the Tupaia kidney is considerably higher than in the rat (radio-immunoassay). The sympathetic innervation of the kidney and especially of the JGA is abundant in Tupaia (fluorescence and electron microscopy). Catecholamine contents of the kidney and other organs are significantly higher in Tupaia than in rats (spectrophotofluorometry). Our results support the previously developed concept of a potent intrarenal neuroendocrine interaction at the JGA level favouring, under certain conditions of social stress, the development of acute renal failure in Tupaia belangeri.
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    URL: http://dx.doi.org/10.1007/BF00236504
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    Electron microscopic study of the paracortical postcapillary “high endothelial venules” in lymph nodes of the normal calf (1980)
    Springer
    Cell & tissue research 212 (1980), S. 465-474 
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    ISSN: 1432-0878
    Keywords: Postcapillary venules ; Calf ; Lymph nodes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of the postcapillary “high endothelial venules” (HEV) of lymph nodes in calves was studied light and electron microscopically. These venules were detected light microscopically in the paracortical zone by their high cuboidal endothelium, a distinct basal lamina, the migration of lymphocytes through the vessel wall, and the dominance of lymphoid cells in the lumen, often completely obliterating the latter. Ultrastructurally, the endothelial cells (HEC) of the HEV were characterized by a prominent Golgi complex including many small vesicles, a few lysosome-like bodies, and a specific association between mitochondria and rough endoplasmic reticulum (MER). The HEC are connected by desmosomes, whereas the intimate contact points between migrating lymphocytes and endothelial cells could not be classified according to the well-defined junctional types. Lymphocyte migration occurred predominantly intercellularly, i.e., between endothelial cells. Although the overall appearance of the described vessel type in bovines bears resemblance to HEV in other investigated species, several differences occur that most probably are related to species variation.
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    Sensory organs inIps typographus (Insecta: Coleoptera) — Fine structure of antennal sensilla (1982)
    Springer
    Protoplasma 111 (1982), S. 206-214 
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    ISSN: 1615-6102
    Keywords: Bark beetle ; Sensilla ; Chemoreceptors ; Mechanoreceptors ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The antennal sensilla inI. typographus are almost exclusively confined to the flattened terminal flagellar segment. The sensillar types have distinct distribution patterns in the three areas where they are found. Judging from the ultrastructural characteristics the following functions can be assigned to the sensillar types: chemoreception, single-walled and double-walled sensilla; chemoreception/mechanoreception, terminal-pore sensillum. Moreover there are two types of mechanoreceptors, one of which is connected to a bristle, whereas the other terminates within the cuticle of the flagellar segment.
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    Some observations onHaemohormidium cotti Henry 1910, from the marine fishCottus bubalis euphrasen (1980)
    Springer
    Parasitology research 62 (1980), S. 31-38 
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    ISSN: 1432-1955
    Keywords: Haemohormidium cotti ; Light microscopy ; Electron microscopy ; Taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Haemohormidium cotti, an organism of uncertain status, is redescribed from one of its type hosts, the marine fish,Cottus bubalis. The parasite occurs as irregularly round, oval, or elongate, intraerythrocytic bodies within blood and tissue preparations. Electron micrographs show features which suggest thatH. cotti may, as previously suspected, belong with the Piroplasmasida but no firm evidence of this is established. Possible division stages are identified in both light and electron micrographs. The taxonomic position ofHaemohormidium is discussed.
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    Babesia microti (Apicomplexa: Piroplasmida): Electron microscope detection in salivary glands of the tick vectorIxodes ricinus (Ixodoidea: Ixodidae) (1980)
    Springer
    Parasitology research 64 (1980), S. 113-115 
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    ISSN: 1432-1955
    Keywords: Babesia microti ; Electron microscopy ; Ticks ; Ixodes ricinus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
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    URL: http://dx.doi.org/10.1007/BF00927061
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    Cells and intercellular contacts in glomeruli and tubules of the frog kidney (1982)
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    Cell & tissue research 226 (1982), S. 589-608 
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    ISSN: 1432-0878
    Keywords: Kidney (frog) ; Glomerulus ; Nephron ; Tight junctions ; Freeze-fracturing ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary By the use of thin sections and freeze-fracture replicas the glomerular and tubular structures of the kidney of the frog (Rana esculenta) were studied with special reference to intercellular junctions. In the glomerulus the filtration barrier is of very variable thickness, and frequent tight and gap junctional contacts occur between podocyte processes. Although structurally less elaborate, the proximal tubule resembles its mammalian counterpart. In the initial part the tight junctions are relatively shallow but become very broad in the mid and distal portions of the proximal tubule. The proximal tubular cells are extensively linked by gap junctions. In some animals the shapes of the cells in the proximal and distal portions of the proximal tubule were markedly different. The distal tubule consists of two segments which differ mainly in the pattern of interdigitations and the structure of the zonulae occludentes. Similarities with the tight junctional morphology of the mammalian distal tubule are striking. In the first part of the distal tubule (diluting segment) a narrow band of parallel tight junctions is found closely resembling that found in the mammalian straight distal tubule; in the more distal part of the distal tubule, however, a broad band of anastomosing tight junctional strands exists, like the zonula occludens of the mammalian convoluted distal tubule. The connecting tubule displays cellular dimorphism: its wall contains a mixture of light and dark (flask) cells. The luminal and basolateral membranes of the flask cells are covered with numerous rod-shaped particles. The tight junctions of the connecting tubule are broad and increase in depth and number of strands along its length; they are typical of a very tight epithelium. In spite of several dissimilarities with phylogenetically younger kidneys our findings suggest that many structural principles of the mammalian kidney are also represented in the kidneys of amphibians. The structural-functional relationships are discussed.
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    Pancreatic polypeptide (PP)- and glucagon cells in the pancreatic islet of Xiphophorus helleri h. (Teleostei) (1980)
    Springer
    Cell & tissue research 205 (1980), S. 187-198 
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    ISSN: 1432-0878
    Keywords: Pancreatic polypeptide (PP) ; Glucagon ; Pancreatic islet ; Xiphophorus helleri ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé L'étude immunohistochimique de l'îlot pancréatique du poisson téléostéen Xiphophorus helleri, à l'aide de sérums anti-polypeptide pancréatique (PP) et anti-glucagon a permis de montrer que deux populations cellulaires distinctes sont responsables de la sécrétion de ces hormones. L'observation comparée de coupes sériées, ultrafines et semifines, traitées par la technique immunohistochimique, a démontré que les cellules à PP correspondent aux cellules qui avaient été précédemment définies, dans cette espèce, comme “cellules A2 à grains ronds” et que les cellules sécrétrices de glucagon sont les “cellules A2 à grains cristallins”. L'hypothèse de l'existence de deux catégories de cellules à glucagon chez les téléostéens est abandonnée.
    Notes: Summary Correlative immunohistochemical and electron microscopical studies on the pancreatic islet of the teleost fish Xiphophorus helleri using antibodies to pancreatic polypeptide (PP) and glucagon show that separate cell types are responsible for the production of these peptides. The PP-cells correspond to the previously described “A2-cells with round granules”, while the “A2-cells with crystalline granules” are the true glucagon cells. An earlier suggestion that there are two types of glucagon cells in teleost islets is therefore withdrawn.
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    The number and arrangement of elements in the lamina cartridge of the dragonfly Sympetrum rubicundulum (1980)
    Springer
    Cell & tissue research 206 (1980), S. 395-401 
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    ISSN: 1432-0878
    Keywords: Dragonfly visual system ; Lamina ganglionaris ; Monopolar cells ; Optic neuropile ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Five monopolar cells and two long visual fibres are a consistent component of the lamina cartridge of the ventral half of the eye of the dragonfly Sympetrum rubicundulum. They communicate with the chiasm via a cartridge axon bundle comprising a minimum of ten fibres. The arrangement of these elements is documented with respect to the ommatidial photoreceptor axon bundle innervating them. These relationships are described both within the lamina cortex and in the cross-section of the underlying cartridge.
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    Lactate sensitive cells in newt kidneys (1980)
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    Cell & tissue research 207 (1980), S. 233-239 
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    ISSN: 1432-0878
    Keywords: Kidney ; Triturus cristatus carnifex ; Erythropoiesis ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Specimens of Triturus cristatus carnifex (Laurenti), raised in 3.2 g/l solution of sodium lactate, presented hypertrophy of “lactate sensitive cells” (LSC) clustered at the vascular pole of each renal corpuscle. As seen under both the light and electron microscopes, these are specialized cells of the Bowman's capsule located at the junction between its visceral and parietal layers. The structure formed by the cells, heretofore unknown, is topographically associated with the juxtaglomerular apparatus. As lactate stimulates erythropoiesis even in normal oxygenated specimens and hypoxia induces hypertrophy of LSC in newts, it is hypothesized that the LSC are the site of erythropoietin (ESF) synthesis. A scheme of ESF biogenesis in newts, integrating the above principles, concludes the paper.
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    Ontogeny and organization of the stationary non-lymphoid cells in the human thymus (1980)
    Springer
    Cell & tissue research 207 (1980), S. 287-306 
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    ISSN: 1432-0878
    Keywords: Fetal human thymus ; Epithelial cells ; Development and differentiation ; Mesenchymal reticulum cells ; T lymphocytes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ontogenetic differentiation of the human thymus was investigated in 50 embryos by means of light and electron microscopic methods in an attempt to clarify the morphogenesis of the complicated microecology of thymic tissue. At the 8th gestational week (g.w.), the primordium of the thymus contains almost exclusively undifferentiated epithelial cells. At the 10th g.w., the epithelial cells in the central part are spindle-shaped. During the subsequent weeks the cortical region of the thymus becomes separated into lobes by mesenchymal septa containing hemopoietic precursor cells and large electronlucent cells with irregularly shaped nuclei. The latter cells are also found in the deeper presumptive medullary regions of the thymus; they differentiate into interdigitating reticulum cells (IDC). The permeation of the medulla of the thymus by non-epithelial IDC occurs concurrently with the formation of cortical and medullary epithelial cells. Between the 12th and 14th g.w. the cortical and medullary differentiation is completed. At this time-stage cortical small lymphocytes differ in morphological shape from medullary lymphocytes, the latter acquiring the appearance of immunocompetent T cells and establishing intimate contact with the IDC. These findings indicate that the thymic cortex and medulla contain different epithelial cells. In addition, the thymic medulla displays cells characterized by the morphology of typical interdigitating reticulum cells of peripheral lymphoid tissue. The structural pattern of the thymus is correlated to morphologically differing lymphoid cell populations in the cortical and medullary regions.
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    Scanning and transmission electron microscopic study of the supraependymal macrophages in the lateral ventricles of the toad brain (1980)
    Springer
    Cell & tissue research 207 (1980), S. 321-329 
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    ISSN: 1432-0878
    Keywords: Supraependymal cells ; Macrophages ; Electron microscopy ; Lateral ventricles ; Amphibian brain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Transmission and scanning electron microscopy of the lateral ventricles of the toad brain revealed the presence of supraependymal cells that have the features of macrophages. Based solely on their surface morphology three different cell forms could be identified. The most frequently observed cells are flat and multipolar, and have a smooth or ruffled surface. The second type is spherical with a ruffled surface and occurs either singly, in which case it lacks processes, or in clusters from which processes radiate. The third type has surface blebs and numerous thin, smooth processes. However, when specimens that had been examined in the scanning electron microscope are viewed in the transmission electron microscope, all cells appear to belong to a single cell type. All cells viewed closely resemble macrophages in that they contain nuclei with clumped chromaffin, single cisternae of rough endoplasmic reticulum, numerous dense bodies, and many Golgi complexes. In addition, when horseradish peroxidase (HRP) was perfused into the ventricles, reaction product was found a short time thereafter within cytoplasmic vacuoles, and after a longer period within dense bodies. Because of their ultrastructural resemblance to macrophages and their capacity to ingest HRP, we suggest that these cells function as phagocytes and, as such, act to remove foreign materials from the cerebrospinal fluid.
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    Organ culture of the islets of Langerhans from young and senescent rats (1980)
    Springer
    Cell & tissue research 207 (1980), S. 429-448 
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    ISSN: 1432-0878
    Keywords: Islet of Langerhans ; Aging ; Insulin-secreting cells ; Organ culture ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The B-cells of the endocrine pancreas constitute an adequate model for in vitro study of the aging process in highly differentiated cells. In the present study, collagenase-isolated islets of Langerhans from young and senescent rats were cultured up to 28 days. The response of the B-cells to the stimulatory conditions of the culture medium involved the nucleus, ribosomes, endoplasmic reticulum, Golgi apparatus, and secretory granules. Correlated data from light microscopy, electron microscopy, and insulin radioimmunoassay show that the differentiation and function of senescent B-cells are maintained in culture, as it has been proven for the B-cells of younger animals. On the other hand, signs of cytological deficiency not directly concerned with the specific function of B-cells were observed: abnormal mitochondria and lysosomes are more numerous in the senescent B-cells. The proliferative capacity of the B-cells of aged rats is reduced.
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    An electron microscopic study of the salivary gland of Rhynchosciara angelae (1980)
    Springer
    Cell & tissue research 207 (1980), S. 449-461 
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    ISSN: 1432-0878
    Keywords: Rhynchosciara angelae ; Salivary gland ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of the salivary gland of the dipteran insect Rhynchosciara angelae in a defined stage of the larval development, characterized by the synthesis and storage of secretion product, is described. Observations were made with both Nomarski optics and electron microscopy. Filiform projections extending into the lumen of the gland were observed in the apical portion of the cells. At the basal region junctions, characterized as hemidesmosomes, were observed between the membrane of the cell and the basal lamina. The plasma membrane presents numerous infoldings into the cell increasing considerably the surface area at this region. Throughout the cytoplasm of the gland cells numerous mitochondria, Golgi complexes, microtubules, profiles of endoplasmic reticulum, secretion granules and glycogen granules were observed. Carbohydrates were detected on ultrathin sections by using the periodic acid-silver methenamine and the periodic acid-thiosemicarbazide-silver proteinate techniques.
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    Fibre types in the locomotory muscles of an antarctic teleost, Notothenia rossii (1980)
    Springer
    Cell & tissue research 208 (1980), S. 143-164 
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    ISSN: 1432-0878
    Keywords: Locomotory muscle ; Fibre types ; Antarctic fish (Notothenia rossii) ; Histochemistry ; Electron microscopy ; Energy metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The metabolic and structural differentiation of locomotory muscles of Notothenia rossii has been investigated. In this species sustained locomotion is achieved by sculling with enlarged pectoral fins (labriform locomotion), whilst the segmental myotomal muscle is reserved for burst activity. Red, white and subepidermal fibres can be distinguished in the trunk by histochemical and ultrastructural criteria. The main pectoral muscle (m. adductor profundus) consists entirely of red fibres. These three main fibres types show differences in histochemical staining profiles, capillarization, myofibril shape and packing, and lipid and mitochondrial content. The fractional volume of mitochondria amounts to 38% for pectoral, 30% for red myotomal and 1.9% for white myotomal fibres. Enzyme activities of red pectoral muscle are consistent with a higher potential for aerobic glucose and fatty acid oxidation than for the red myotomal fibres. Mg2+ Ca2+ -myofibrillar ATPase activities are similar for red pectoral and myotomal muscles and approximately half of those white fibres. Specialisations of N. rossii muscles associated with labriform swimming and locomotion at Antarctic temperatures are discussed.
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    The fine structure of the stomach mucosa of the llama (Llama guanacoe) (1980)
    Springer
    Cell & tissue research 208 (1980), S. 207-228 
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    ISSN: 1432-0878
    Keywords: Hind stomach ; Fundic glands ; Electron microscopy ; Histochemistry ; Endocrine cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The epithelium of the fundic region mucosa of the hind stomach in the Llama guanacoe has been studied using morphological and histochemical methods. Morphology suggests that solute and water absorption may occur in the epithelium of the surface and of the foveolae, although this absorption can not be estimated because of the extensive secretion of the gastric glands. The same cells of the surface and foveolar epithelium show numerous secretory granules. The glands reveal neck cells, chief cells, a large number of oxyntic cells, four types of endocrine cells (A-like, ECL, D and EC), brush cells and wandering cells. PAS and Alcian blue reactions for light microscopy suggest a secretion of neutral and acidic mucosubstances in the surface and foveolar epithelium, of neutral mucosubstances only in the neck cells. Periodic acid-thiocarbohydrazide silver proteinate (PA-TCH-SP) reaction for electron microscopy confirms the presence of neutral mucosubstances within the secretory granules of the surface, foveolar and neck epithelial cells. In all these cells, the reaction product is also evident within sacculi and vesicles of the maturing surface of the Golgi apparatus. A positive PA-TCH-SP reaction also occurs on the membrane (and not on the contents) of the Golgi apparatus (maturing surface) and of the secretory granules of the chief cells as well as on the membrane of the Golgi apparatus and of apical vesicles and tubules of the oxyntic cells. In addition, silver granules slightly enhance the electron density of the contents of the secretory granules in the endocrine cells. Morphological and histochemical findings are discussed and compared with results described by others for monogastric mammals.
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    The synaptic organization of visual interneurons in the lobula complex of flies (1980)
    Springer
    Cell & tissue research 208 (1980), S. 371-387 
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    ISSN: 1432-0878
    Keywords: Lobula complex ; Visual interneurons ; Ultrastructure ; Cobalt-impregnations ; Electron microscopy ; Diptera (Calliphora erythrocephala)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The synaptic organization of three classes of cobalt-filled and silver-intensified visual interneurons in the lobula complex of the blowfly Calliphora (Col A cells, horizontal cells and vertical cells) was studied electron microscopically. The Col A cells are regularly spaced, columnar, small field neurons of the lobula, which constitute a plexus of arborizations at the posterior surface of the neuropil and the axons of which terminate in the ventrolateral protocerebrum. They show postsynaptic specializations in the distal layer of their lobula-arborizations and additional presynaptic sites in a more proximal layer; their axon terminals are presynaptic to large descending neurons projecting into the thoracic ganglion. The horizontal and vertical cells are giant tangential neurons, the arborizations of which cover the anterior and posterior surface of the lobula plate, respectively, and which terminate in the perioesophageal region of the protocerebrum. Both classes of these giant neurons were found to be postsynaptic in the lobula plate and pre- and postsynaptic at their axon terminals and axon collaterals. The significance of these findings with respect to the functional properties of the neurons investigated is discussed.
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    The pineal complex of the three-spined stickleback, Gasterosteus aculeatus L. (1980)
    Springer
    Cell & tissue research 209 (1980), S. 11-28 
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    ISSN: 1432-0878
    Keywords: Epiphysis cerebri ; Parapineal organ ; Fluorescence histochemistry ; Electron microscopy ; Gasterosteus aculeatus L ; Teleostei
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pineal complex of the three-spined stickleback (Gasterosteus aculeatus L.) was investigated by light and electron microscopy, as well as fluorescence histochemistry for demonstration of catecholamines and indolamines. The pineal complex of the stickleback consists of a pineal organ and a small parapineal organ situated on the left side of the pineal stalk. The pineal organ, including the entire stalk, is comprised mainly of ependymal-type interstitial cells and photoreceptor cells with well-developed outer segments. Both unmyelinated and myelinated nerve fibres are present in the pineal organ. Nerve tracts from the stalk enter the habenular and posterior commissures. A small bundle of nerve fibres connects the parapineal organ and the left habenular body. The presence of indolamines (5-HTP, 5-HT) was demonstrated in cell bodies of both the pineal body and the pineal stalk, and catecholaminergic nerve fibres surround the pineal complex.
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    Lipid droplets in the visceral yolk sac endodermal cells of the postimplantation rat embryo: Application of malachite green-glutaraldehyde fixative (1980)
    Springer
    Cell & tissue research 209 (1980), S. 29-41 
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    ISSN: 1432-0878
    Keywords: Visceral yolk sac ; Lipid droplets ; Malachite green-glutaraldehyde fixative ; Rat embryo ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the visceral yolk sac (VYS) of the rat embryo at day 9.5 of gestation was examined after fixation with either Karnovsky's glutaraldehyde-paraformaldehyde solution or malachite green-containing glutaraldehyde (MGA) solution. Fixation with MGA retained homogeneously electron-dense droplets in the cytoplasm and the nucleus of endodermal cells, both of which were lost in the specimens prepared by Karnovsky's fixation method. The cytoplasmic MGA-positive droplets were frequently associated with other cytoplasmic organelles such as rough endoplasmic reticulum, mitochondria and membrane-delineated inclusion bodies, but these cytoplasmic organelles never incorporated MGA-positive materials, whereas Golgi apparatus contained intracisternal MGA-positive droplets. Extracellular MGA-positive droplets were also encountered at the apical surface of endodermal cells and in the intercellular space between endodermal cells and the underlying mesodermal cells. These MGA-positive droplets were considered to be lipid in nature, and their origin in the endodermal cells of VYS is discussed.
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    Hypothalamo-hypophysial function following the lesion of tanycytes in the median eminence of the rat (1980)
    Springer
    Cell & tissue research 209 (1980), S. 225-238 
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    ISSN: 1432-0878
    Keywords: Tanycytes ; Median eminence ; Electron microscopy ; Rat ; Serum LH
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The transport of hormones from the cerebrospinal fluid to the adenohypophysis by the tanycytes of the median eminence was examined in male rats. Electron microscopy revealed that all ependymal cells including the tanycytes disappear or degenerate in rats subjected to electric cauterization of the ependymal layer lining the third ventricle. However, the granular axons in the palisade layer of the median eminence remain intact. In rats subjected to electric lesion, no significant change was found in either the serum-LH level or in the weight of the adenohypophysis, testes, adrenal and thyroid glands. It is concluded that the tanycytes do not participate in the hypothalamic regulation of hypophysial function.
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    Induction of intranuclear microtubules in chick embryo fibroblasts by frog virus 3 (1980)
    Springer
    Cell & tissue research 209 (1980), S. 271-277 
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    ISSN: 1432-0878
    Keywords: Intranuclear microtubules ; Chick embryo fibroblasts ; Frog Virus 3 ; Electron microscopy ; Tubulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Intranuclear microtubules appear in chick embryo fibroblasts upon infection with Frog Virus 3 (FV 3). Both the diameter and the annular shape of the microtubule profiles, established from electron microscopic observations using a goniometer, suggest that they are identical to naturally occurring cytoplasmic microtubules. Furthermore, the use of vinblastine allowed demonstration of the tubulin composition of the intranuclear microtubules.
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    The origin of the dendritic reticulum cell (1980)
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    Cell & tissue research 209 (1980), S. 279-294 
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    ISSN: 1432-0878
    Keywords: Germinal center reaction ; Dendritic reticulum cell ; Rabbit spleen ; Enzyme histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To obtain more information concerning the origin of dendritic reticulum cells, the development of germinal centers in the spleens of rabbits was investigated by conventional light microscopy, enzyme histochemistry, and electron microscopy. Washed sheep erythrocytes were used as antigen. Splenic tissue was examined on the 13th, 18th, 21st, 27th and 48th day after antigen administration. Electron microscopic investigations revealed transitional forms between typical fibroblastic reticulum cells, which formed the framework of the entire splenic white pulp, and typical dendritic reticulum cells. During this transformation, the enzyme histochemical pattern of alkaline phosphatase disappeared and a positive alpha-naphthyl acetate esterase reaction appeared in the transformed cells. On the basis of these findings, it is highly likely that dendritic reticulum cells develop through transformation of fibroblastic reticulum cells during the development of germinal centers in rabbit spleens. The characteristic folding of the surface membrane of dendritic reticulum cells is probably caused by the conspicuous increase in size of the Golgi apparatus, the detachment of vesicles, and the uptake of such vesicles by the cell membrane observed electron microscopically during the cellular transformation. Receptors that are of significance in antigen trapping might reach the cell surface in this manner, i.e., with the Golgi vesicles.
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    Dense material associated with apparent presynaptic elements in cell cultures of the CNS (1980)
    Springer
    Cell & tissue research 211 (1980), S. 95-103 
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    ISSN: 1432-0878
    Keywords: Synapse ; Synaptogenesis ; Cell culture ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In cell cultures of the rat cerebellum, electron-dense material has been found occasionally between adjacent cells. More often than not, presynaptic elements on one side of the dense material faced either neuronal or nonneuronal cells on the other side. The 20 nm thick material was stained either with the osmium-uranyl-lead (OsUL) procedure or with the ethanolic phosphotungstic acid (E-PTA) procedure. To determine the source of the dense material, various compounds were added to cultures at 7 days in vitro. Only a crude nuclear fraction was able to duplicate the appearance of the dense material associated with the apparent presynaptic elements. It was concluded that apparent presynaptic elements were associated with the polybasic dense material and that this type of association may duplicate an interaction in the normal development of synaptic contacts.
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    The tight junctions of renal tubules in the cortex and outer medulla (1980)
    Springer
    Cell & tissue research 212 (1980), S. 395-413 
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    ISSN: 1432-0878
    Keywords: Kidney ; Distal tubule ; Collecting duct ; Electron microscopy ; Thin sections ; Freeze fracturing ; Tight junctions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Quantitative aspects of tight junction morphology were systematically studied in the cortical and outer medullary segments of the distal urinary tubules of rat, hamster, rabbit, cat, dog and the primitve primate Tupaia belangeri. Only minor differences in junctional architecture were found between straight and convoluted portions of the distal tubule. In contrast, the collecting duct in cortex and outer medulla, in all species, exhibits the most elaborate tight junctions observed along the uriniferous tubule. The present and previous findings from this laboratory indicate that increasing “tightness” of the junctional complexes is apparent along the course of the nephron in all species studied. The proposed relationship between quantitative aspects of the zonula occludens and presently available values for transepithelial electrical resistance was re-examined for the renal tubules. It was found that for the mammalian kidney a satisfactory correlation exists between the tight junction morphology and presently known functional parameters. This relationship is the more evident the more additional dimensional characteristics of the intercellular clefts are taken into consideration. It may therefore be concluded that, at least for the mammalian kidney, the assumption of differences in the molecular organization of the tight junctions is not needed to explain so far unresolved discrepancies between tubular morphology and function.
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    An electron microscopic study on stellate cells in the rabbit adenohypophysis under various endocrine conditions (1980)
    Springer
    Cell & tissue research 213 (1980), S. 237-246 
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    ISSN: 1432-0878
    Keywords: Stellate cell ; Nongranulated cell ; Adenohypophysis ; Rabbit ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Stellate cells in the rabbit adenohypophysis were observed electron microscopically under normal and experimental conditions such as lactation, thyroidectomy, adrenalectomy, or castration. In control animals stellate cells had a scanty cytoplasm surrounding the nucleus and possessed slender processes extending between granulated cells. The processes were interconnected by desmosomes to form a meshwork. In the cytoplasm, abundant microfilaments were present as well as ill-developed ordinary cell organelles, but secretory granules were absent. In the adenohypophysis of experimental groups, in which the granulated cells underwent characteristic changes, stellate cells also showed remarkable morphological alterations which were similar in all groups. In general, they became hypertrophied, and contained a well-developed Golgi apparatus and rough-surfaced endoplasmic reticulum. Lysosomes or lipid droplets were frequently encountered. Between adjacent stellate cells, intercellular canals were markedly developed and many microvilli were noticed. Based on the above data, it is suggested that the stellate cells are not only sustentacular elements, but play an important role in the function of the adenohypophysis, such as the supply of materials to granulated cells or the disposal of waste products.
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    The programming of silk-gland development in Bombyx mori (1980)
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    Cell & tissue research 213 (1980), S. 311-324 
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    ISSN: 1432-0878
    Keywords: Bombyx ; Silk-gland ; Starvation ; Development ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The cytological development of the silk gland has been studied by light and electron microscopy in silkworms experimentally starved at different periods of the natural feeding stage during the fifth instar. When newly molted animals are not provided with food, no sign of growth is observed. Starvation initiated early during the obligatory feeding period, stops cell growth and development of the organelles involved in protein synthesis and secretion, whereas it induces the appearance of organelles concerned with autolysis. These effects are reversible if starvation is not prolonged beyond two days. Starvation during the facultative feeding period, at the time of massive fibroin production, results in quantitative and qualitative modifications of organelles related to the decrease of fibroin production and the onset of autolysis. Rough endoplasmic reticulum, responsible for fibroin synthesis, forms transitory whorls. Fibroin transport via the Golgi apparatus and secretion of the protein into the gland lumen decrease parallel to fibroin synthesis, so that no fibroin storage can be detected in any organelle. After food deprivation, autophagosomes and secondary lysosomes rapidly develop in the cytoplasm, and if starvation continues portions of the cytoplasm are sequestered and completely destroyed. If animals are refed, fibroin production is resumed and autolysis declines. These ultrastructural alterations of the silk gland during experimental starvation are very similar to those observed during the periods of physiological starvation (molt and cocoon spinning) and generally considered to be under hormonal control. Our results raise the question of the nature of interactions between alimentary and hormonal factors which control silk-gland development.
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    Ultrastructure of endocrine cells in the stomach of two teleost fish Perca fluviatilis L. and Ameiurus nebulosus L. (1982)
    Springer
    Cell & tissue research 221 (1982), S. 657-678 
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    ISSN: 1432-0878
    Keywords: Stomach (Teleost) ; Endocrine cells ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the gastric mucosa of two teleost species, the perch (Perca fluviatilis) and the catfish (Ameiurus nebulosus) three endocrine cell types were found, located predominantly between the mucoid cells of the gastric mucosa. A fourth cell type is present in the gastric glands of catfish. Each cell type was defined by its characteristic secretory granules. Type-I cells were predominant in both fish. These cells contained round or oval granules with a pleomorphic core. The average diameter of granules was 400 nm for the perch and 270 nm for the catfish. Type-II cells of both species displayed small, highly osmiophilic granules about 100 nm in diameter. The secretory granules of type-III cells (260 nm in the perch and 190 nm in the catfish) were round or slightly oval in shape and were filled with a finely particulate electron-dense material. Type-IV cells of the catfish were found in the gastric glands only. Their cytoplasm was filled with homogeneous, moderately electron-dense granules averaging 340 nm in diameter. The physiological significance of these different morphological types of gastric endocrine cells requires further investigation.
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    Apical region of the crayfish retinula (1982)
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    Cell & tissue research 222 (1982), S. 409-415 
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    ISSN: 1432-0878
    Keywords: Crustacean compound eye ; Eighth retinular cell ; Crystalline tract ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The base of the crystalline tract, the distal part of the eighth retinular cell and its rhabdomer constitute a structural unit in the apical region of the retinula of Astacus fluviatilis and A. leptodactylus, shielded from the blood by a special covering cell.
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    Electron-microscopic localization of A2B5 cell surface antigen in monolayer cultures of murine cerebellum and retina (1982)
    Springer
    Cell & tissue research 224 (1982), S. 637-645 
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    ISSN: 1432-0878
    Keywords: Cell surface antigen ; Neurons ; Glia ; Electron microscopy ; Immunoperoxidase ; Monoclonal antibody
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Immuno-electron microscopy was performed on live, cultured, early postnatal cerebellar and retinal cells of the mouse to identify A2B5 antigenbearing elements. In cerebellar cultures, granule cells, some immature oligodendroglia, and astroblasts express A2B5 antigen on their cell surfaces. The typical features of astroblasts include large cisternae of the endoplasmic reticulum and a mixed population of intermediate-sized filaments and microtubules. Immature oligodendroglia cells express the antigen on their cell bodies and on procecesses filled with cytoplasm. Cytoplasm-free membranous whorls, however, are devoid of A2B5 antigen, but not of 0 or NS-1 antigens. In retinal cultures, A2B5 antigen is observed on differentiating neurons with the exception of photoreceptor cells as identified by ribbon synapses.
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    Survival of Pacinian corpuscles after denervation in adult rats (1982)
    Springer
    Cell & tissue research 224 (1982), S. 673-683 
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    ISSN: 1432-0878
    Keywords: Pacinian corpuscles, rat ; Denervation ; Sensory terminals ; Nerve degeneration ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of Pacinian corpuscles located on the crural interosseous membrane was studied in adult rats 6 h to 10 months after transection of the right sciatic nerve. Axon terminals degenerated one day after transection and were engulfed and resorbed by cells of the inner core within one week. The axial space left after removal of the axonal debris was closed by the lamellae of the inner core. The main structural features of the inner core and capsule remained preserved after denervation throughout the period of study. The denervated inner cores, however, became atrophic 10 months after neurotomy, their mean diameter being reduced by 17.5% compared with that of contralateral control corpuscles. The number of capsular lamellae was unaltered, and perineurial pathways of the peripheral nerve stump remained preserved. Schwann cells proliferated and formed Büngner bands during the first month after denervation, but retracted their processes and became atrophic at later stages after neurotomy. Survival of Pacinian corpuscles after long-term denervation in adult rats is in contrast to their rapid degeneration within several days after nerve section in neonates.
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    Close apposition of muscle cells in the longitudinal bands of the body wall of a holothurian, Isostichopus badionotus (1982)
    Springer
    Cell & tissue research 227 (1982), S. 465-473 
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    ISSN: 1432-0878
    Keywords: Electron microscopy ; Junctions ; Smooth muscle ; Echinodermata ; Holothuria, Aspidochirotida
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscopy reveals that sarcolemmata of adjacent muscle cells form pentalaminar junctions by fusion of apposed trilaminar double leaflet membranes. These junctions appear to be candidates for low resistance pathways between muscle fibers. The muscles depolarize slowly when bathed in solutions containing elevated concentrations of KCl, and the sucrose gap method can then be used to measure the potential difference between polarized and depolarized regions. Thus the junctions which we have observed may provide the structural basis for electrical transmission through the sucrose gap.
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    Penetration of the peritrophic membrane of the tick by Babesia microti (1982)
    Springer
    Cell & tissue research 221 (1982), S. 471-481 
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    ISSN: 1432-0878
    Keywords: Peritrophic membrane ; Tick ; Babesia ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A peritrophic membrane (PM) has been demonstrated in the gut of feeding larvae, nymphs, and adults of the tick Ixodes dammini. This is the first report of a PM in ticks. This temporary structure divides the lumen of the gut into two compartments, an endoperitrophic space, the lumen proper, and an ectoperitrophic space located between the PM and the epithelial cells of the gut wall. The PM is a mechanical barrier and even such small particles as ribosomes derived from ingested reticulocytes are retained in the lumen proper; they are never found in the ectoperitrophic compartment. In Ixodes dammini fed on hamsters infected with Babesia microti some of the parasites are found in the ectoperitrophic space. This passage is accomplished by a highly specialized organelle, the arrowhead, which develops in some Babesia during their metamorphosis in the gut of the vector. The arrowhead, while passing through the PM, changes its fine structure and loses its internal organization as if releasing some of its contents. Its disintegration continues and it disappears shortly after the Babesia have entered the epithelial cells. Only Babesia equipped with the arrowhead structure are able to cross the PM. This is the first documented case of a parasite traversing a solidified PM.
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    Paddle cilia (discocilia) in chemosensitive structures of the gastropod mollusk Pleurobranchaea californica (1982)
    Springer
    Cell & tissue research 222 (1982), S. 25-40 
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    ISSN: 1432-0878
    Keywords: Paddle cilia ; Discocilia ; Pleurobranchaea ; Chemoreceptors ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Scanning electron microscopy of various regions of the body of the marine gastropod Pleurobranchaea californica (McFarland) has revealed a characteristic cell type that bears cilia with dilated discoid-shaped tips. The tips of the cilia consist of an expansion of the ciliary membrane around a looped distal extension of the axoneme. These kinocilia have been observed in numerous other marine invertebrates and are generally referred to as paddle cilia (Tamarin et al. 1974) or discocilia (Heimler 1978). Although many functions have been proposed for paddle cilia, little empirical evidence supports any of the proposals. In Pleurobranchaea we have found that the distribution of this ciliated cell type corresponds exactly to areas of the body known from behavioral studies (Lee et al. 1974; Davis and Matera 1981) to mediate chemoreception. Transmission electron microscopy of the epithelium lining the rhinophores and tentacles of Pleurobranchaea revealed details of the ultrastructure of these ciliated cells and showed that they are primary receptors. These ciliated receptors lie in a yellow-brown pseudostratified columnar epithelium that superficially resembles the olfactory mucosa of vertebrates.
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    URL: http://dx.doi.org/10.1007/BF00218286
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    Pigment biogenesis in freshwater shrimp ventral nerve chord chromatophores (1982)
    Springer
    Cell & tissue research 222 (1982), S. 167-175 
    Details
    ISSN: 1432-0878
    Keywords: Pigment granules ; Chromatophores ; Granulogenesis ; Palaemonid shrimp ; Macrobrachium ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The possible biogenesis of two pigment granule types present in the monochromatic, brown chromatosomes enveloping the ventral nerve chord of the freshwater palaemonid shrimps Macrobrachium acanthurus, M. heterochirus and M. olfersii is examined by transmission electron microscopy in thin section and freeze fracture replicas. Prominent, membrane limited granules are suggested to have their origin in a complex, juxtanuclear, smooth endoplasmic reticulum labyrinth, continuous with the nuclear envelope. Amembranous, lipocarotenoid granules possibly derive from the external surface of the smooth endoplasmic reticulum. Nuclear envelope and SER membranes contain numerous 11 nm diameter intramembranous particles while pigment granule membranes exhibit fewer particles. A dictyosomal origin for the lipocarotenoid granules is discounted. Granulogenesis is suggested to be a continuous process in crustacean chromatophores.
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    URL: http://dx.doi.org/10.1007/BF00218297
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    Ultrastructural duality of extrafusal fibers in a slow (tonic) skeletal muscle (1982)
    Springer
    Cell & tissue research 222 (1982), S. 261-267 
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    ISSN: 1432-0878
    Keywords: Skeletal muscle ; Fiber types ; Electron microscopy ; Stereology ; Chicken
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural and stereological assessment of the mature avian anterior latissimus dorsi (ALD) muscle showed that it contains two kinds of extrafusal fibers. This fine structural dichotomy of fiber types in the ALD correlated well with their previously reported histochemical duality. Distinct differences occur in sarcomere banding, myofibrillar area, sarcotubular and mitochondrial density, and in morphology of motor-nerve terminals. Both myofiber types in this muscle were interpreted as representing varieties of “slow” or tonic muscle fibers. Both fibers contain myofibrils that, despite differences in cross-sectional area, were large, irregular, and ribbon-shaped, typical of the “Felderstruktur” appearance of true “slow” fibers. Whereas the majority of fibers (type-1) are devoid of well-defined M-bands, the minor fiber population (type-2) exhibit prominent M-bands in the center of each sarcomere. In addition, type-1 tonic fibers contain a significantly lower mitochondrial and sarcotubular volume than the tonic fibers of type-2. While both fiber types exhibit motor-nerve terminals that are small, smooth and punctate in appearance, those on the type2 fibers often had a number of shallow postjunctional folds. Whether or not these two classes of extrafusal fiber in this muscle represent two separate and distinct types of motor units remains to be determined functionally.
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    URL: http://dx.doi.org/10.1007/BF00213211
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    Fine structure of arterial smooth muscle cells cultured in the presence of whole blood serum or plasma-derived serum (1982)
    Springer
    Cell & tissue research 223 (1982), S. 87-99 
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    ISSN: 1432-0878
    Keywords: Smooth muscle cells ; In vitro-growth ; Whole blood serum ; Plasma-derived serum ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Normal diploid cells require serum to proliferate in culture. Platelet-derived growth factor has been identified as the main serum component responsible for this effect. Here, smooth muscle cells were isolated enzymatically from the aorta of 5-day-old rats and cultured in the presence of 10% whole blood serum (WBS) or plasma-derived serum (PDS), i.e. with or without platelet factor, and studied by transmission electron microscopy. The cells proliferated actively in WBS-medium but remained quiescent in PDS-medium. Fine structurally, cells from WBS-cultures demonstrated numerous mitochondria, an extensive rough endoplasmic reticulum (RER), a large Golgi complex, a few lysosomes, and microfilaments arranged in parallel bundles. After transfer to PDS-medium, the RER- and Golgi cisternae were markedly dilated and the number of membrane-associated ribosomes decreased. Segregation of fragments of cytoplasm within autophagosomes was frequently observed and the number of lysosomes increased. Lipid droplets were more abundant and often gathered in the Golgi area. Moreover, the cells had become more irregular in shape and showed many bleb-like processes at their surface. Microfilament bundles had also become more prominent and crossed each other in different directions. These observations show that the removal of platelet factor from the medium clearly modifies the fine structure of cultured smooth muscle cells. The findings are in good agreement with the concept that platelet factor not only supports the proliferation of cultured cells but also stimulates their secretory activity.
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    URL: http://dx.doi.org/10.1007/BF00221501
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    Effect of hyper- and hypoosmotic solutions on the structure of theAstacus retina (1982)
    Springer
    Cell & tissue research 223 (1982), S. 267-280 
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    ISSN: 1432-0878
    Keywords: Retina (Astacus) ; Rhabdom ; Osmolarity ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Alterations of the retinula cells in the retina of the light-adapted crayfish in response to hyper- and hypoosmotic van Harreveld solutions was examined by transmission electron microscopy. Increased osmolarity of the bathing medium to twice that of the physiological value leads to shrinkage of the retinula-cell somata. Microvilli, on the other hand, do not undergo shrinkage. Some other characteristic irreversible changes do, however, take place, including detachment of microvilli from the soma, showing a two- or threefold increase in diameter, and a concomitant decrease in number, probably due to fusion of microvilli. Prolonged incubation or higher osmolarities (5 isosmol) cause alteration of the microvillar membranes to whorls. Structural changes are often restricted to microvillar stacks evaginating from certain individual retinular cells. The number of affected stacks increases depending on the duration of incubation or the osmotic pressure. Hypoosmotic solution (0.5 isosmol) also induces an increase of microvillar diameters and a concomitant reduction in number of microvilli per stack. Exposure to a 20% solution of glycerol causes destruction of the rhabdom structure and the formation of whorls from microvillar membranes. The present findings suggest that the structure of the microvilli is stabilized by an axial cytoskeleton.
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    URL: http://dx.doi.org/10.1007/BF01258488
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    Interdigitating cells and macrophages in the acute involuting rat thymus (1982)
    Springer
    Cell & tissue research 224 (1982), S. 291-301 
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    ISSN: 1432-0878
    Keywords: Thymus (rat) irradiation ; Electron microscopy ; Interdigitating cells ; Macrophages ; Phagocytosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Phagocytic activity and population development of medullary interdigitating cells (IDC) and cortical macrophages have been studied in the rat thymus after irradiation-induced thymocyte necrosis. IDC clearly demonstrate phagocytic activity, particularly in the 16h stage after irradiation. At this stage the number of necrotic thymocytes is maximal and the total number of phagocytic cells is insufficient to phagocytize all necrotic material. IDC increase in number slightly and are predominantly phagocytizing in the corticomedullary region (CMR), where they appear to develop from macrophage-like cells. The results indicate that medullary IDC can be phagocytic but have a different developmental pathway than cortical macrophages. Cortical macrophages greatly increase in number and acquire the appearance of tingible body macrophages by phagocytizing many necrotic thymocytes. They seem to develop from monocytes that normally enter the thymus at the CMR. During the acute involution macrophages probably also enter the cortex via the connective tissue capsule. It is suggested that thymus medullary IDC probably belong to the mononuclear phagocytes, as do the cortical macrophages. In the specific medullary environment IDC gradually develop their characteristic ultrastructure for an apparently other than phagocytic function. The similarities between IDC and epidermal Langerhans cells are discussed.
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    URL: http://dx.doi.org/10.1007/BF00216874
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    Ultrastructural changes of the stigma of the follicle during the process of ovulation in the hen (1982)
    Springer
    Cell & tissue research 224 (1982), S. 349-359 
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    ISSN: 1432-0878
    Keywords: Ovarian follicle ; Ovulation ; Ultrastructural change ; Fowl ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary No structural changes could be observed in the stigma until 2 h before ovulation. Within a few minutes of ovulation, the stratum granulosum and theca interna disappear completely in the middle part of the stigma. By 30 min before ovulation, the rough endoplasmic reticulum in the fibroblasts of the theca externa develops conspicuously. Then a few minutes before ovulation, the theca externa becomes much thinner with a conspicuous disintegration of the collagenous fibers into individual fibrils. These structural changes may contribute to the fragility of the stigma tissue and induce rupture of the follicle.
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    URL: http://dx.doi.org/10.1007/BF00216878
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    Cellular interconnections in the young mouse ovary (1982)
    Springer
    Cell & tissue research 224 (1982), S. 383-395 
    Details
    ISSN: 1432-0878
    Keywords: Mouse ovary ; Junctions ; Freeze-fracture ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Intercellular junctions in the young mouse ovary were examined by electron microscopy utilizing freeze-fracture and thin-sectioning techniques. Projections from the granulosa cells adjacent to the oocyte (GI) traverse the zona pellucida and form small gap junctions on the oocyte surface. On the P-face of these cells, the junctional aggregations are occasionally associated with linear strands of particles. In contrast, large gap junctional areas are frequently observed between the more peripherally located granulosa cells (GE) and are also present in the theca interna (TI) cell layer surrounding the follicles. Three types of tight junctional strands are discernible on the P-face of theca externa cells (TE): angularly zigzag strands consisting of intermittently distributed intramembranous particles on wide ridges, intermediate zigzag strands consisting of more continuously distributed particles, and wavy strands consisting of rather fused particles. Tight junctional strands are also present in the middle of grooves on the E-face of endothelial cells of blood vessels. In the germinal epithelial cell layer, tight junctional strands appear to be discrete and form a less anastomosing network.
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    URL: http://dx.doi.org/10.1007/BF00216881
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    Ultrastructure of the pars intermedia of the developing sheep hypophysis (1982)
    Springer
    Cell & tissue research 224 (1982), S. 369-381 
    Details
    ISSN: 1432-0878
    Keywords: Pituitary gland ; Pars intermedia ; Electron microscopy ; Fetal sheep ; Lamb
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using light and electron microscopy, the morphogenesis of the pars intermedia of the sheep pituitary gland was examined in developing lambs between 26 days of gestation and the newborn stage. Following the establishment of contact between the anterior and posterior lobe primordia seen at 26 days, the connection with the pharyngeal roof disappeared by 31 days. The lumen of Rathke's pouch, which was a prominent cavity at the earlier stages, became inconspicuous by 40 days but progressively increased in size during gestation and, in some newborn animals, contained colloid material. At 40 days, the pars intermedia consisted of a uniform population of undifferentiated cells. Cells with cytoplasmic granules were first identified at 50 days. The cytological appearance of granular cells at 70 days indicated increased synthetic activity and by 80 days they closely resembled adult glandular cells. At 100 days, membrane activity suggestive of exocytosis was first observed in granular cells; fenestrated capillaries were present, and early follicle formation between adjacent non-granular cells was seen. This apparent exocytotic release of granules was observed much more frequently between 100 days of gestation and the newborn stage than in adult pars intermedia cells. These findings indicate that glandular cells of the developing pars intermedia are actively engaged in synthesis, storage and secretion from an early stage.
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    URL: http://dx.doi.org/10.1007/BF00216880
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    Endometrial ultrastructure in the early uterine response to blastocysts and artificial deciduogenic stimuli in rats (1982)
    Springer
    Cell & tissue research 225 (1982), S. 355-364 
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    ISSN: 1432-0878
    Keywords: Implantation ; Blastocyst ; Pontamine ; blue reaction ; Decidualization ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The early uterine response to transplanted, delayed and estrogenactivated blastocysts was studied ultrastructurally and compared with that induced by intrauterine instillations of deciduogenic agents (arachis oil, air). The uterine responses to delayed and activated blastocysts showed no ultrastructural or temporal differences. Already within 4 h after transfer to a sensitized uterus, the delayed blastocysts exhibited signs of activation, and both types of blastocysts had started to attach onto an undamaged epithelial lining. Signs of stromal cell differentiation into decidual cells were also seen as early as 4 h after transfer, while the Pontamine-blue reaction did not appear until after 8 h. The results therefore indicate that the transplanted blastocysts induced decidualization atraumatically and that the delayed blastocysts were either deciduogenic already before transfer or rapidly acquired deciduogenic properties after transfer. Artificial decidual induction with oil and air led to damage or death of a large number of cells in the uterine luminal epithelium. Within only 15 min after instillation pronounced signs of cell damage were seen, and later numerous cells were extruded from the epithelial lining. In the stroma ultrastructural signs of decidual cell differentiation and a Pontamine-blue reaction were observed as early as 4 h after induction. It is therefore suggested that oil and air induce decidualization via the epithelium by means of trauma.
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    URL: http://dx.doi.org/10.1007/BF00214688
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    Ultrastructural studies on the ventricular surface of the frog cerebellum (1982)
    Springer
    Cell & tissue research 225 (1982), S. 443-448 
    Details
    ISSN: 1432-0878
    Keywords: Frog cerebellum ; Ependymal surface ; Cilia ; Supraependymal cells ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural studies of the ventricular surface of the frog cerebellum showed regional differences. In the midline region of the adult cerebellum was found a band of profusely ciliated squamous ependymal cells. In the rest of the cerebellum the ependymal cells were columnar and each had a single cilium. In the cerebellum of the premetamorphic tadpole, the squamous ependymal cells of the midline region also were monociliated. During metamorphosis they gradually became multiciliated. Additionally, supraependymal cells and synaptic elements were present on the ventricular surface of the cerebellum of adult frogs as well as in late metamorphic tadpoles. In contrast, supraependymal cells were rarely observed in premetamorphic tadpoles, and it was concluded that the supraependymal system develops during metamorphosis. It is postulated that the band of cilia may be associated with the circulation of cerebrospinal fluid, and supraependymal synaptic elements function in neuroendocrine regulation.
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    URL: http://dx.doi.org/10.1007/BF00214695
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    Further studies on the junctional complex in the intestine of Sagitta setosa (1982)
    Springer
    Cell & tissue research 225 (1982), S. 663-671 
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    ISSN: 1432-0878
    Keywords: Chaetognatha ; Intestine ; Pleated septate junction ; Electron microscopy ; Freeze-fracture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The intramembrane structures of the pleated septate junction which occur in the junctional complex of the intestine of the chaetognath Sagitta setosa have been investigated. The pleated septate junction is made up of linear rows of irregularly shaped and sized particles, often fused into short rods, and pits which can be fused into furrows. The distribution of these structures on E and P faces depends upon the preparative methods used. Many of the morphological characteristics are the same as those of the “lower invertebrate pleated septate junction type” defined by Green (1981a). The physiological significance of this junction is obscure. On the basis of the presence of septate junctions (both of the paired septate junction and pleated septate junction types) which have mainly morphological characteristics of the “lower invertebrate pleated septate junction” we can add to the hypothesis that chaetognaths are not related to the molluscs and arthropods.
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    URL: http://dx.doi.org/10.1007/BF00214811
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    An immunocytochemical and electron-microscopical study of endocrine cells in the gut and pancreas of a stomachless teleost fish, Barbus conchonius (Cyprinidae) (1982)
    Springer
    Cell & tissue research 227 (1982), S. 577-593 
    Details
    ISSN: 1432-0878
    Keywords: Enteroendocrine cells ; Pancreatic endocrine cells ; Gastroenteropancreatic hormones ; Immunocytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Four immunoreactive endocrine cell types can be distinguished in the pancreatic islets of B. conchonius: insulin-producing B cells, somatostatin-producing A1 (= D) cells, glucagon-producing A2 cells and pancreatic poly-peptide-producing PP cells. The principal islet of this species contains only a few PP cells, while many PP cells are present in the smaller islets. Except for the B cell all pancreatic endocrine cell types are also present in the pancreatic duct. At least six enteroendocrine cell types are present in the gut of B. conchonius: 1. a cell type (I) with small secretory granules, present throughout the intestine, and possibly involved in the regulation of gut motility; 2. a C-terminal gastrin immunoreactive cell, probably producing a caerulein-like peptide; these cells are located at the upper parts of the folds, especially in the proximal part of the intestinal bulb; 3. a met-enkephalin-immunoreactive cell, present throughout the first segment; 4. a glucagon-immunoreactive cell, which is rare in the first segment; 5. a PP-immunoreactive cell, mainly present in the first half of the first segment; 6. an immunoreactive cell, which cannot at present be specified, located in the intestinal bulb. The latter four cell types are mostly located in the basal parts of the folds, although some PP-immunoreactive cells can also be found in the upper parts. Most if not all enteroendocrine cells are of the open type. The possible functions of all enteroendocrine cell types are discussed.
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    URL: http://dx.doi.org/10.1007/BF00204788
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    Splenic white pulp as a thymus-independent area in the African clawed toad, Xenopus laevis (1982)
    Springer
    Cell & tissue research 226 (1982), S. 327-335 
    Details
    ISSN: 1432-0878
    Keywords: Xenopus ; Spleen ; B-lymphocyte ; Immunofluorescence ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An indirect immunofluorescence study of the frozen sections of the spleen of an anuran amphibian, Xenopus laevis, showed that lymphocytes bearing a small amount of immunoglobulin (Ig) were localized mostly in the white pulp of non-immunized toads. There were fewer fluorescent cells in the red pulp. In the toads hyperimmunized with human gamma globulin (HGG), cells with strong cytoplasmic fluorescence increased significantly in the outer part of the white pulp. Electron microscopy of spleens from these toads showed that plasma cells at different stages of maturation were abundant in the white pulp, whereas in the red pulp, a smaller number of maturer plasma cells were observed. These results indicate that, in contrast with its mammalian counterpart, the splenic white pulp of this anuran is the site where thymusin-dependent lymphocytes commence blast formation and transformation into plasma cells.
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    URL: http://dx.doi.org/10.1007/BF00218363
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