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  • 1970-1974  (36)
  • 1830-1839
  • 1974  (22)
  • 1971  (14)
  • Computational Chemistry and Molecular Modeling  (21)
  • Electron Microscopy  (15)
Materialart
Erscheinungszeitraum
  • 1970-1974  (36)
  • 1830-1839
Jahr
  • 1
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 467-489 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A variational calculation of the interaction between two H2 molecules using minimal basis set of 1s functions is performed to check the efficiency of various versions of the perturbation theory for intermolecular interactions. The matrix procedure starting with the zero-order Hamiltonian which is symmetric with respect to intermolecular electron permutations shows better convergence than the procedures using nonsymmetric zero approximations. This conclusion follows from the calculations of ground state and four lowest excited states for three geometric configurations of the H4 system. The behaviour of the potential curves is interpreted in terms of symmetric perturbation theory. The various contributions to the interaction energy are considered in detail. The importance of charge transfer states for the description of the intermediate range of intermolecular separations is specially emphasized.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1432-0533
    Schlagwort(e): Neuronal Ceroid Lipofuscinosis ; Electron Microscopy ; Membranous and Fingerprint Inclusions ; Hypertrophied Cortical Astrocytes ; Nuclear Bodies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Sommaire Deux cas de la maladie de Batten-Spielmeyer-Vogt (idiotie amaurotique familiale juvénile) ont été étudiés en microscopie électronique, histochimiquement et biochimiquement. Le premier cas, dont l'histoire clinique a débuté à l'âge de 3 ans, a révélé des inclusions cytoplasmiques dans les cellules neuronales et gliales, composées de membranes fréquemment disposées en paires. La structure de ces inclusions était identique à l'examen du matériel autopsié six mois plus tard. Dans le deuxième cas, dont l'histoire clinique date de 4 ans et 4 mois, les inclusions étaient plus pléomorphes: elles étaient en général plus denses en électronique et comportaient fréquemment un élément à l'aspect d'«empreintes digitales». Quelques inclusions membraneuses semblables à celles du premier cas y ont également été retrouvées. En outre ont été observées une hypertrophie cytoplasmique prononcée des astrocytes corticaux, et une grande fréquence de cils, de corps basaux et de corps nucléaires dans ces astrocytes. Un paquet de filaments intranucléaires a été observé dans un neuron. Les données neurochimiques n'ont révélé aucune abnormalité dans les lipides ou les protéines du premier cas, ou dans les gangliosides du second. Malgré les différences morphologiques qui les caractérisent, la présence simultanée des deux types d'inclusions cytoplasmiques dans le même cas suggère qu'elles peuvent représenter des stages divers dans l'évolution du même processus fondamental. Il est possible que ce soit l'âge de la cellule nerveuse, lors de l'atteinte métabolique dont elle est l'object, qui détermine ces différences.
    Notizen: Summary Electron microscopic, histochemical and neurochemical studies on two cases of Batten-Spielmeyer-Vogt disease (juvenile amaurotic familial idiocy) are presented. In the first case, with the clinical onset at the age of 3 years, cytoplasmic neuronal and glial inclusions consisted of membranous bodies, the membranes of which were frequently paired. The fine structure of these inclusions was unaltered when examined in autopsy material 6 months later. In case 2, with the clinical onset at 4 years and 4 months, the inclusions were more pleomorphic: they were usually more electron-dense, and frequently showed a characteristic “fingerprint” pattern component. A few membranous inclusions resembling those in case 1 were also present. Additional findings included marked cytoplasmic hypertrophy of inclusion-containing cortical astrocytes, and frequent cytoplasmic cilia, basal bodies, and nuclear bodies in the hypertrophic astrocytes. A packet of intranuclear filaments was found in one neuron. Neurochemical studies failed to reveal any abnormality of lipid or protein pattern in case 1, or of ganglioside pattern in case 2. Despite the morphological differences between the two types of cytoplasmic inclusions, the presence of both types within the same case suggests that they may represent different stages in the evolution of a single process. It is conceivable that such differences are related to the age of the neuron when the postulated intracellular defect first becomes manifest.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 18 (1971), S. 327-341 
    ISSN: 1432-0533
    Schlagwort(e): Infantile Neuroaxonal Dystrophy ; Electron Microscopy ; Striated Muscle ; Membranous-Tubular Structures ; Filamentous Structures
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary This paper deals with the first ultrastructural study of muscle fiber in a child affected by infantile neuroaxonal dystrophy or Seitelberger's disease. In a first step, diagnosis was performed by light and electron microscopy in biopsy and autopsy findings in central and peripheral nervous system. Muscle fiber and axonal changes are very similar. The ultrastructure findings in muscle fiber are as follows: 1. neural atrophy, 2. overproduction of membrano-tubular structures related to sarcoplasmic reticulum hyperplasia, 3. filamentous aggregates by presumed overproduction of myofilaments, 4. overproduction of abnormal mitochondria. These changes, already described in various muscular diseases, are not specific; they seem related to an abnormal muscle fiber reaction in close association to dystrophic axonal endings.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Pflügers Archiv 329 (1971), S. 59-71 
    ISSN: 1432-2013
    Schlagwort(e): Myosin Adenosinetriphosphatase ; Cardiac Performance ; Glycogen ; Electron Microscopy ; Skeletal Muscle
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The relationship between cardiac function and 1. myocardial glycogen concentration, 2. ultrastructure, and 3. myosin ATPase activity was studied in cats at various times following adrenalectomy. These three variables were also studied in gastrocnemius and soleus muscles from the same cats. Cardiac glycogen concentration was decreased in adrenal insufficient cats 11 days after withdrawal of steroid therapy, a time at which cardiac performance was already severely depressed. Skeletal muscle glycogen levels did not significantly decrease after adrenalectomy. Electron micrographs of the heart and the soleus at 8 days revealed normal myofibrils and mitochondria, but a shorter mean sarcomere length was observed in cardiac muscle. The ATPase activities of myosin isolated from the red fibered cativity of myosin isolated from the predominantly white fibered gastrocnemius muscle appeared to be unaffected by adrenalectomy. Regression analysis of cardiac function on cardiac myosin ATPase activity for adrenalectomized, dexamethasone-treated, and intact control animals revealed a significant correlation (p〈0.001) between cardiac performance and myosin ATPase activity.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 163-169 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The connection between the electron coordinates permutation group and the molecular point group is exhibited in the framework of the Heitler-London method. It is shown that the initial wave function of a molecule in the Heitler-London method can be written in such a form, that the effect of the point group operations upon this function corresponds to the permutation of the sets of electron coordinates of the ions and the subsequent multiplication of this function by some constants.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 171-177 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: In the framework of the Heitler-London method, a method for determining the allowed molecular multiplets is proposed. The method is based on the connection of the total molecular spin with the permutation symmetry of the coordinate wave function and on the isomorphism of the molecular point group with a certain subgroup of the electron permutation group. The method does not depend on the approximation in which the molecular ions are considered.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 8 (1974), S. 45-60 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Spin-projected one-particle density and spin density matrices are presented as polynomials of suitable unprojected quantities with generalized Sasaki-Ohno coefficients. Thus an explicit form of Harriman's theorems is given. For the two-particle spatial density matrix an expansion in direct products of powers of unprojected residual electron and spin density matrices is given. For these basic matrices of the scheme the variational spin-extended equations are formulated.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 27 (1974), S. 43-53 
    ISSN: 1432-0533
    Schlagwort(e): Oncocytes ; Adenohypophysis ; Pituitary Adenoma ; Secretory Granules ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A light and electron microscopic study was undertaken on 3 surgically removed non-tumorous adenohypophyses and 16 pituitary adenomas. Numerous oncocytes have been found in 2 non-tumorous adenohypophyses and in 6 pituitary adenomas including 1 chromophobe adenoma which was composed almost exclusively of oncocytes. Thus, it seems that the occurrence of oncocytes in the anterior pituitary cannot be considered a rare finding. The distinctive feature of oncocytes is the abundance of mitochondria in their cytoplasm. This alteration can be so extensive that the entire cytoplasm is filled with mitochondria leaving only a small area for the remaining cytoplasmic organelles. Oncocytes arise from adenohypophysial cells. This transformation is gradual and is not restricted to one particular cell type. In the early phases of development of oncocytes the secretory granules are well preserved. Thus, hormone secretion is presumably maintained. It seems conceivable, however, that in the more advanced phases of evolution of oncocytes, when the secretory granules decrease in number, hormone production is diminished or stopped. Further investigations are, however, required to elucidate in detail the functional activity of oncocytes. It remains to be established whether mitochondrial accumulation is principally due to increased formation or delayed breakdown. As some mitochondria show signs indicating division it appears that multiplication of mitochondria is the underlying mechanism resulting in their significant increase. However, the possibility cannot be excluded that the life span of mitochondria is prolonged and mitochondrial longevity plays an important role in causing transformation of adenohypophysiocytes into oncocytes.
    Materialart: Digitale Medien
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  • 9
    ISSN: 1432-0533
    Schlagwort(e): Progressive Multifocal Leukoencephalopathy ; Hirano Bodies ; Papova Virus ; Paramyxovirus-like ; Nuclear Bodies ; Electron Microscopy ; Neurofibrillary Tangles
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We have identified three structures that have not previously been reported in electron microscopic examinations of brain from patients with PML: 1. coiled nuclear bodies that may possibly represent tubular paramyxovirus nucleocapsids, 2. Hirano bodies and 3. Neurofibrillary tangles. The paramyxovirus-like material is interesting in view of reports of a transition between nuclear bodies and tubular paramyxovirus nucleocapsids and because of a possible interaction between syncytiogenic paramyxoviruses and Papova viruses in the pathogenesis of SSPE and PML. A study of the Hirano bodies in this case, taken in conjunction with the findings of others leads us to believe that these structures are formed from an overgrowth of neurofilaments. The presence of tangled masses of neurofilaments in the processes of neurons also seen in the present case is consistent with this hypothesis.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 17 (1971), S. 302-309 
    ISSN: 1432-0533
    Schlagwort(e): Synaptic Degeneration ; Tricresylphosphate Intoxication ; Spinal Cord ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Eine elektronenoptische Untersuchung der Synapsen-Degeneration im Vorderhorn des Rückenmarks vom Huhn wurde nach Gabe einer Einzeldosis von 0,5 cm3 Tricresylphosphat durchgeführt. Die Fixation erfolgte durch Perfusion mit 6% Glutaraldehyd. Degenerative Veränderungen fanden sich in den synaptischen Vesikeln und Mitochondrien des präsynaptischen Abschnittes. Diese Befunde werden mit Läsionen durch mechanische Schädigung und Bestrahlung verglichen. Es wird angenommen, daß sich der toxische Effekt von TCP sicher im Synapsenareal manifestiert. Dieses zeigt dabei Veränderungen ähnlich wie nach mechanischer oder Strahlenschädigung.
    Notizen: Summary A study has been made of synaptic degeneration at an ultrastructural level using 6% glutaraldehyde perfusion, fixation method in the anterior horn of hen's spinal cord, after application of a single dose of 0.5 cm3 TCP on the comb. The degenerative changes are seen in the synaptic vesicles and mitochondria of pre-synaptic bag. A comparison of these findings is made with degenerative changes caused by mechanical interference and x-irradiation. It is concluded that the toxic effects of TCP are certainly manifested in the synaptic areas which show changes similar to those caused by the mechanical interference and by x-irradiation.
    Materialart: Digitale Medien
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