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  • 1
    Electronic Resource
    Electronic Resource
    Age-related changes in the glutamate metabolism of cerebral cortical slices from rats (1982)
    Springer
    Neurochemical research 7 (1982), S. 679-685 
    Details
    ISSN: 1573-6903
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The glutamate metabolism in cerebral cortical slices from young (12 weeks) and aged (100 weeks) rats was studied. A highly significant reduction of low affinity glutamate uptake and its metabolism in the aged rats by 14.5% of the amount of the young rats was observed (Pº0.001). When the ratio of the radioactivity of respective metabolite divided by the sum total radioactivity of overall glutamate metabolites was compared, the incorporation to aspartate was significantly small (P〈0.01), while that of the CO2 liberated and the GABA synthesized were increased (P〈0.05). These results support the hypothesis that in cerebral cortical slices from aged rats the transamination of glutamate is suppressed and its decarboxylation is enhanced despite markedly reduced low affinity glutamate uptake into the cerebral cortex. The difference could be explained by the fact that cerebral cortical slices from aged rats are more vulnerable to anoxia than those from young rats when exposed during slice preparation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00965521
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  • 2
    Electronic Resource
    Electronic Resource
    Microscopic Computed Tomography Based on Generalized Analytic Reconstruction from Discrete Samples (1996)
    Springer
    Optical review 3 (1996), S. 22-28 
    Details
    ISSN: 1349-9432
    Keywords: image reconstruction ; image estimation ; computed tomography ; microscope ; double-axis optical system ; generalized inverse ; singular value decomposition ; continuous-to-discrete model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We propose a computed tomography (CT) for the incoherent optical system based on a generalized analytic reconstruction method from discrete samples (GARDS), by which an object image defined in a continuous space is reconstructed from discrete images acquired through the imaging system. We apply this method to reconstruct depth structures of micro-specimens using conventional fluorescence microscopes. Also, we discuss the optimal sampling distance in the depth direction through a generalized singular value decomposition of a continuous-to-discrete imaging system. We next apply the GARDS-based CT method to a double-axis microscope, in which two microscopes are set up perpendicularly to cover a missing frequency band of each microscopic imaging system. We show simulation results which verify the effectiveness of our proposed method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10043-996-0022-9
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  • 3
    Electronic Resource
    Electronic Resource
    Two ultrastructurally distinct types of transporting tissues, the branchiostegal and the gill epithelia, in an estuarine tanaid, Sinelobus stanfordi (Crustacea, Peracarida) (1993)
    Springer
    Zoomorphology 113 (1993), S. 253-260 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary On each lateral side of the cephalothorax segments, the adult Sinelobus stanfordi has a branchial chamber which contains an elongated bag-shaped gill and is covered by a thick branchiostegite. The ultrastructural study revealed that the inner surface of the branchiostegite is composed of a transporting-type epithelium which is morphologically distinct from the gill epithelium. Both epithelia are covered by extremely thin (about 80 nm) cuticle layers, suggesting high permeability to gases, ions, and water. In contrast, the outer surface of the branchiostegite consists of ordinary epithelium covered by a very thick cuticle layer in common with the body surface. The inner branchiostegal epithelium (4–10 μm thick) has a shallow (about 1 μm deep) apical infolding system of the cell membrane (AIS) and an extensive three-dimensional tubular network (about 120 nm in diameter) which is formed by the invagination of the basolateral cell membrane (TNB). The TNB is associated with slender mitochondria and occupies the majority of the cytoplasmic area of the epithelial cell. The gill epithelium, on the other hand, is about 10 μm thick and characterized by an abundance of oval mitochondria, well-developed (4–5 μm deep) AIS, and a smooth basal cell membrane lacking any infoldings. These morphological features indicate that not only the gill epithelia, but also the inner branchiostegal epithelia, are involved in the ion-transporting processes. The ultrastructural differences between these two kinds of epithelia also suggest their different roles in the osmoregulation of this animal, since it inhabits estuaries which are subject to extreme changes in salinity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00403316
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  • 4
    Electronic Resource
    Electronic Resource
    Age-related changes of glucose metabolism in rat cerebral cortex with reference to glucose-derived amino acids (1985)
    Springer
    Neurochemical research 10 (1985), S. 1615-1622 
    Details
    ISSN: 1573-6903
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The parietal cortical slices obtained from 8 week-old (young) and 78 week-old (middle-aged) male Wistar rats were incubated withd-[U-14C]glucose in oxygensaturated Gey's balanced salt solution. Subsequently, the radioactivities of liberated CO2 and glucose-derived amino acids (alanine, aspartate, GABA, glutamate and glutamine) obtained from the slices were measured. In the middle-aged rats as compared to the young rats, the amount of radioactivity of CO2 (P〈0.01) and glutamate (P〈0.05) showed a significant raduction with glutamine unchanged, while that of alanine (P〈0.01), aspartate (P〈0.05) and GABA (P〈0.05) increased significantly. The results indicate that with advancing age the overall glucose oxidation in the cerebral cortex declines but the metabolic pathway to form amino acids is not uniformly suppressed. Therefore, the above characteristic glucose metabolism could be related to the development of heterogeneous enzyme activities associated with aging in the brain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00988603
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  • 5
    Electronic Resource
    Electronic Resource
    Free amino acid changes in the cerebral cortex of experimental uremic rat (1983)
    Springer
    Neurochemical research 8 (1983), S. 313-318 
    Details
    ISSN: 1573-6903
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The levels of free amino acids in the cerebral cortex of acute and chronic uremic rats were examined. Amino acids significantly elevated were aspartate, glutamine, glycine, histidine, ornithine, phenylalanine, phosphoethanolamine and taurine, whereas 1-methyl histidine and 3-methyl histidine were specifically detected in uremic rats. Glutamate, arginine and carnosine disclosed a significant reduction. There was no change in the concentrations of γ-aminobutyrate and alanine. The above findings were essentially identical in both acute and chronic uremia. It was conjectured that these changes of amino acid levels in the brain might participate in the progress of uremic encephalopathy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00965721
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  • 6
    Electronic Resource
    Electronic Resource
    Mitochondria-rich (chloride) cells in the gill epithelia from four species of stenohaline fresh water teleosts (1977)
    Springer
    Cell & tissue research 180 (1977), S. 87-98 
    Details
    ISSN: 1432-0878
    Keywords: Chloride cell ; Stenohaline freshwater teleosts ; Gill epithelia ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The mitochondria-rich (chloride) cells have been found to be present in the gill epithelia of four species of stenohaline fresh water teleosts. The cytoplasm of these chloride cells contains an extensive network of cytoplasmic tubules which communicate with intercellular spaces bordering the lateral and basal cell surfaces. Numerous vesicles with fairly electron-dense interiors are also present in the apical cytoplasm of chloride cells. The apical surface of a chloride cell forms an apical pit, but the lumen of the pit does not appear to be in continuity with the interior of the apical vesicles and tubules inside the cell. When Carassius auratus were kept in 100, 200, 300, and 400 mOsm-diluted sea water for a month, no appreciable changes occurred in the number and fine structure of the chloride cells, except for a dilation of the apical vesicles and a slight decrease in diameter of the cytoplasmic tubules in these cells in the fishes kept in 300 and 400 mOsm. These results suggest that chloride cells may be a rather common occurrence in the gill epithelia of stenohaline fresh water teleosts, and may function in ion-transport in these fishes in fresh water environments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227031
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  • 7
    Electronic Resource
    Electronic Resource
    The structure and innervation of the sinu-atrial node of the mole heart (1976)
    Springer
    Cell & tissue research 172 (1976), S. 345-356 
    Details
    ISSN: 1432-0878
    Keywords: Mole heart ; SA node ; Innervation ; Neuromuscular relationship ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The sinu-atrial node in the heart of the mole, Mogera wogera, contains myocytes which are devoid of atrial specific granules and which may be classified into two types: electron-lucent (majority) and dark (minority). Numerous unmyelinated axon terminals, containing synaptic vesicles, face the nodal myocyte surface with interspaces of less than 300 nm. There are about 6 terminals per myocyte profile and about 10 per profile at nuclear levels. Of a total of 2717 of these terminals 85.2% are 50–200 nm from the nodal myocytes, and 9.6% form closer neuromuscular junctions, with less than 50 nm interspace and some membrane specialization. Such specializations are almost exclusively found in relation to the dark, minority-type of nodal myocyte. Myelinated nerve fibers are also numerous within the mole SA node, and may terminate almost directly on a nodal myocyte. A few nerve fibers contain many mitochondria and may represent afferent endings. Nodal capillaries are smaller and fewer than capillaries in the juxtanodal myocardium, probably indicating a lesser blood supply to the SA node than to the ordinary myocardium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00399517
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  • 8
    Electronic Resource
    Electronic Resource
    The fine structure of the gill epithelium of a fresh-water flea, Daphnia magna (Crustacea: Phyllopoda) and changes associated with acclimation to various salinities (1983)
    Springer
    Cell & tissue research 229 (1983), S. 253-268 
    Details
    ISSN: 1432-0878
    Keywords: Fine structure ; Gill epithelium ; Crustacea ; Daphnia magna
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Two kinds of epithelial cells, dark and light types, are alternately arranged in the gill of Daphnia magna. The dark cell has numerous mitochondria and an elaborate tubular system containing two kinds of cytoplasmic tubules, small about 70 nm in diameter, and large about 130 nm in diameter. The former occur in bundles and seem to be smooth surfaced endoplasmic reticulum. The latter, lined with a ridged surface coat and frequently open at the lateral and basal cell membrane, are regarded as extensions of the cell membrane. The apical cell membrane of the dark cell is modified by repeated subunits of a cytoplasmic coat on the inner leaflet of the unit membrane. The light cell exhibits a high degree of basal infoldings of the cell membrane, which represent a magnification of the surface area of the cell. Large mitochondria between the infoldings often come into intimate association with the infolded cell membrane to form a regular array of parallel mitochondria interposed with the double cell membranes. The results suggest that at least the dark epithelial cells play an important role in the osmoregulation of this animal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214974
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  • 9
    Electronic Resource
    Electronic Resource
    A tubular configuration of the granular endoplasmic reticulum forming a raft-like parallel array in the pinealocytes of two species of Japanese moles (Mogera kobeae and M. wogura) (1984)
    Springer
    Cell & tissue research 236 (1984), S. 15-18 
    Details
    ISSN: 1432-0878
    Keywords: Granular endoplasmic reticulum ; Ultrastructure ; Pinealocyte ; Mole
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ten or more straight tubules, each of which consists of a double unit membrane of granular endoplasmic reticulum with a cylindrical profile, are joined side by side in a raft-like configuration in the cytoplasm of the pinealocytes of Japanese moles. They measure about 60 nm and 100 nm in their inner and outer diameters, respectively, and are often partially connected to unspecialized granular endoplasmic reticulum. Cisterns held between the inner and outer unit membranes with cylindrical profiles vary from 15 nm to 30 nm in width. Ensheathed portions of the cytoplasm are contiguous with cytoplasm outside the tubular units. The inner unit membranes of the tubules bear fewer ribosomal particles than the outer ones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216507
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