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  • 2005-2009
  • 1995-1999  (2.942)
  • 1990-1994
  • 1970-1974
  • 1890-1899
  • 1995  (2.942)
  • Analytical Chemistry and Spectroscopy  (1.554)
  • Engineering General  (737)
  • Inorganic Chemistry  (567)
  • Ultrastructure
Datenquelle
Materialart
Erscheinungszeitraum
  • 2005-2009
  • 1995-1999  (2.942)
  • 1990-1994
  • 1970-1974
  • 1890-1899
Jahr
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  • 1
    Digitale Medien
    Digitale Medien
    Ultrastructural alterations and environmental exposure influence the opiate concentrations in hair of drug addicts (1995)
    Springer
    International journal of legal medicine 107 (1995), S. 301-305 
    Details
    ISSN: 1437-1596
    Schlagwort(e): Hair ; Opiates ; Drug monitoring ; Ultrastructure ; Environmental conditions ; Hair damage Cosmetic treatment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin , Rechtswissenschaft
    Notizen: Abstract Hair samples were taken at autopsy from the head of 1 male and 1 female subject both known as drug abusers. Some of the strands were bleached by in-vitro cosmetic treatment. The bleached hair as well as the original hair samples were partly exposed to water or soil prior to further investigations and drug monitoring. The exposure times were 4 weeks or 6 months for water and 6 months for soil. The hair fibers were examined by transmission electron microscope (TEM) and by scanning electron microscope (SEM) investigations. The electron microscope studies confirmed that all experimental conditions had produced morphological alterations in the hair fibers. After exposure to water or to soil for 6 months as well as after storage of the clipped bleached hair in tap water at room temperature for 4 weeks, drug monitoring of formerly positive hair samples gave negative results. After storage of natural hair in soil or in water for 4 weeks the opiate levels had dramatically decreased. The samples were screened by fluorescence polarization immunoassay after enzymatic digestion. The results were confirmed by GC/MS.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01246877
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  • 2
    Digitale Medien
    Digitale Medien
    A histological study on experimental autoimmune myocarditis with special reference to initiation of the disease and cardiac dendritic cells (1995)
    Springer
    Virchows Archiv 426 (1995), S. 493-500 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Autoimmune myocarditis ; Cardiac myosin ; Dendritic cell ; Macrophage ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The precise mechanism of myosin-induced autoimmune myocarditis is unknown. The purpose of the present study was to define the immunohistological and ultrastructural characteristics of the infiltrating cells, especially in the initial phase of the myocarditis. It was demonstrated that OX6-positive dendritic cells first infiltrated the cardiocytes on day 13 after immunization. After day 17, OX6-positive cells, which possessed elongated irregular-shaped processes on the cell surface but contained few phago-lysosomes in the cytoplasm, were located at the margin of an inflammatory field and inserted their processes into the sarcoplasm of cardiocytes. The central portion of the inflammatory field was occupied by ED1-positive inflammatory macrophages, which were rich in phagosomes and which were in contact with degenerating cardiocytes. No evidence was obtained which suggested that lymphocytes directly injured the cardiocytes. These results demonstrated ultrastructural evidence that the type of infiltrating cell that first injures cardiocytes is the cardiac dendritic cell. Inflammatory macrophages thereafter serve as scavengers of degenerating cardiocytes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00193173
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  • 3
    Digitale Medien
    Digitale Medien
    Ultrastructure and immunoreactivity of dystrophic axons indicate a different pathogenesis of Hallervorden-Spatz disease and infantile neuroaxonal dystrophy (1995)
    Springer
    Virchows Archiv 427 (1995), S. 415-421 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Hallervorden-Spatz disease ; Infantile neuroaxonal dystrophy ; Axonal dystrophy ; Ultrastructure ; Cytoskeletal proteins
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract An immunohistochemical and ultrastructural analysis of dystrophic axons (DAs) in the brain and peripheral nerve of a patient with familial infantile neuroaxonal dystrophy (INAD) and in the brain of a patient with familial Hallervorden-Spatz Disease (HSD) revealed prevalent membrano-tubular or granulo-vesicular profiles with a graded pattern of evolution in INAD, while dense bodies, vesicles and amorphous material were pressent in HSD. DAs immunoreactivity with τ-protein and 200 kDa-neurofilament antibodies was stronger in HSD than in INAD. In both cases immunohistochemistry was positive for ubiquitin and negative for β-tubulin and β-amyloid. Distinct ultrastructural features and immunoreactivity pattern of cytoskeletal components suggest different pathogenetic mechanisms.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00199391
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  • 4
    Digitale Medien
    Digitale Medien
    Gastrointestinal autonomic nerve tumours and their separation from other gastrointestinal stromal tumours: an ultrastructural and immunohistochemical study of seven cases (1995)
    Springer
    Virchows Archiv 426 (1995), S. 27-35 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Gastrointestinal autonomic nerve tumours ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Gastrointestinal stromal tumours (GIST) represent a heterogeneous group whose classification frequently requires ultrastructural and immunohistochemical studies. In a retrospective study of the ultrastructural findings of 24 gastrointestinal stromal tumours, whose light microscopic study has yielded ambiguous results and in which accurate diagnosis had required ultrastructural support, seven were found to have the characteristics of gastrointestinal autonomic nerve (GAN) tumours. In all of them the diagnosis was based on the presence of dendritic processes with dense neuroendocrine granules. Immunohistochemically, the seven tumours were negative for smooth-muscle markers. All stained positively for vimentin. NSE, chromogranin, and synaptophysin were positive in most of them, while S-100 protein was positive only in two cases. We present the ultrastructural and immunohistochemical features of seven GANT against the background of the GISTs of our series. We conclude that GAN tumours cannot be diagnosed by light microscopy alone but this tumour group displays characteristic electron microscopic and immunohistochemical features and appears to represent a distinct type of GIST.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00194695
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  • 5
    Digitale Medien
    Digitale Medien
    Immunogold labelling of paired helical filaments and amyloid fibrils by specific monoclonal and polyclonal antibodies (1995)
    Springer
    Acta neuropathologica 90 (1995), S. 441-447 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Key words Alzheimer's disease ; Neurofibrillary ; tangles ; Amyloid ; Ultrastructure ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Senile plaque and paired helical filament (PHF) formation are characteristic of Alzheimer's disease, but the mechanisms leading to these lesions still remain unclear. To understand them better, we have performed different immunolabellings of amyloid protein and PHF. We describe a very specific immunodetection of PHF with AD2, a monoclonal antibody directed against a hyperphosphorylated epitope of PHF-tau, and use double immunolabelling to show that PHF and plaque amyloid are discretely labelled by different antibodies. We also discuss different mechanisms of PHF maturation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00294803
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  • 6
    Digitale Medien
    Digitale Medien
    Familial amyloid polyneuropathy associated with transthyretin Gly42 mutation: a quantitative light and electron microscopic study of the peripheral nervous system (1995)
    Springer
    Acta neuropathologica 90 (1995), S. 516-525 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Key words Familial amyloid polyneuropathy ; Transthyretin ; Ultrastructure ; Lectin histochemistry ; Morphometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We performed extensive quantitative analyses of the peripheral nervous system (PNS) of two siblings with familial amyloid polyneuropathy (FAP) caused by a transthyretin (TTR) Gly42 mutation. Pronounced amyloid deposition was found in the sympathetic ganglia (SyG), dorsal root ganglia (DRG) and throughout the length of the peripheral nerve fibers with some accentuation in the more proximal portion. There was severe neuronal loss in the SyG and DRG together with nerve fiber depletion in the nerve trunk, while only a small amount of amyloid deposition with mild fiber loss was seen in the spinal roots. Sprouts of regenerating axons were very scanty even in the spinal nerves or roots. A teased fiber study mainly showed demyelinating fibers, but axonal degeneration was also present throughout peripheral nerves. An electron microscopic study showed fine amyloid fibrils in direct contact with the axoplasmic membrane of demyelinated axons and destruction of axons in some areas. Amyloid deposition within the PNS in this type of FAP resembled that in type I FAP (TTR Met30). However, direct axonal damage by amyloid fibrils appeared to be more prominent in our cases than in type I FAP. Lectin histochemistry using Ulex europaeus agglutinin I demonstrated preferential depletion of small neurons in the DRG and their primary afferent fibers in the spinal dorsal horn. Primary axonal degeneration and ganglionopathy due to amyloid deposition appear to be the pathogenetic mechanisms for peripheral neuropathy in this type of FAP.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00294814
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  • 7
    Digitale Medien
    Digitale Medien
    A monoclonal antibody that recognizes a carbohydrate epitope of human protoplasmic astrocytes (1995)
    Springer
    Acta neuropathologica 91 (1995), S. 23-30 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Key words Protoplasmic astrocyte ; Secondary ; lysosome ; Immunohistochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract By hybridizing mouse myeloma cells with spleen cells from a BALB/c mouse immunized with the glial cell-rich fraction prepared from an autopsied human brain, we established a hybridoma that produces a monoclonal antibody to protoplasmic astrocytes (PA). The antibody, named PRAS-1, consistently labeled cytoplasm of PA with a granular pattern. In a few cases, the cytoplasmic processes of several astrocytes in gray and white matter were also stained. The immunoreactivity was lost after periodic acid treatment or methylation, showing that the epitope is composed of a carbohydrate. The cytoplasmic reaction was resistant to protease digestion and lost after incubation in an organic solvent, suggesting that a glycolipid is the antigen. On the other hand, the reaction in the processes disappeared upon protease digestion. Ultrastructurally, the immunoreaction was localized to secondary lysosomes. Cross-reactivity was noted on a small number of incidental neurons, corpora amylacea, hepatocytes and esophageal epithelial cells. A long period of formalin fixation did not deteriorate the antigenicity. PRAS-1 was demonstrated to detect PA immunohistochemically on paraffin sections, and may be applicable to further investigations into development or neoplasms of human astrocytes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004010050388
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  • 8
    Digitale Medien
    Digitale Medien
    Familial amyloid polyneuropathy associated with transthyretin Gly42 mutation: a quantitative light and electron microscopic study of the peripheral nervous system (1995)
    Springer
    Acta neuropathologica 90 (1995), S. 516-525 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Familial amyloid polyneuropathy ; Transthyretin ; Ultrastructure ; Lectin histochemistry ; Morphometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We performed extensive quantitative analyses of the peripheral nervous system (PNS) of two siblings with familial amyloid polyneuropathy (FAP) caused by a transthyretin (TTR) Gly42 mutation. Pronounced amyloid deposition was found in the sympathetic ganglia (SyG), dorsal root ganglia (DRG) and throughout the length of the peripheral nerve fibers with some accentuation in the more proximal portion. There was severe neuronal loss in the SyG and DRG together with nerve fiber depletion in the nerve trunk, while only a small amount of amyloid deposition with mild fiber loss was seen in the spinal roots. Sprouts of regenerating axons were very scanty even in the spinal nerves or roots. A teased fiber study mainly showed demyelinating fibers, but axonal degeneration was also present throughout peripheral nerves. An electron microscopic study showed fine amyloid fibrils in direct contact with the axoplasmic membrane of demyelinated axons and destruction of axons in some areas. Amyloid deposition within the PNS in this type of FAP resembled that in type I FAP (TTR Met30). However, direct axonal damage by amyloid fibrils appeared to be more prominent in our cases than in type I FAP. Lectin histochemistry using Ulex europaeus agglutinin I demonstrated preferential depletion of small neurons in the DRG and their primary afferent fibers in the spinal dorsal horn. Primary axonal degeneration and ganglionopathy due to amyloid deposition appear to be the pathogenetic mechanisms for peripheral neuropathy in this type of FAP.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00294814
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  • 9
    Digitale Medien
    Digitale Medien
    Apoptotic process of cerebellar degeneration in experimental methylmercury intoxication of rats (1995)
    Springer
    Acta neuropathologica 91 (1995), S. 72-77 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Key words Cerebellar degeneration ; Methylmercury ; intoxication ; Apoptosis ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract This report deals with the mechanism involved in the cerebellar degeneration following experimental methylmercury poisoning of male Wistar rats. The cerebellar granule cells of animals that exhibited typical hind leg paresis were shrunken and displayed marked nuclear pyknosis. At the ultrastructural level, the nuclei of these cells were condensed and fragmented, features which are characteristic of apoptosis. In situ staining for DNA strand breaks revealed that the pyknotic nuclei were positively labeled. DNA fragmentation was confirmed by agarose gel electrophoresis; a ladder pattern of multiples of approximately 200-base pair fragments, typical of apoptosis, was observed with the cerebellar DNA of the methylmercury-treated animals. These observations suggest that the degeneration of cerebellar granule cells by alkyl mercury compounds involves an apoptotic process.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004010050394
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  • 10
    Digitale Medien
    Digitale Medien
    Immunogold labelling of paired helical filaments and amyloid fibrils by specific monoclonal and polyclonal antibodies (1995)
    Springer
    Acta neuropathologica 90 (1995), S. 441-447 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Alzheimer's disease ; Neurofibrillary tangles ; Amyloid ; Ultrastructure ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Senile plaque and paired helical filament (PHF) formation are characteristic of Alzheimer's disease, but the mechanisms leading to these lesions still remain unclear. To understand them better, we have performed different immunolabellings of amyloid protein and PHF. We describe a very specific immunodetection of PHF with AD2, a monoclonal antibody directed against a hyperphosphorylated epitope of PHF-tau, and use double immunolabelling to show that PHF and plaque amyloid are discretely labbeled by different antibodies. We also discuss different mechanisms of PHF maturation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00294803
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  • 11
    Digitale Medien
    Digitale Medien
    Subcortical microtubule network separates the periplasm from the endoplasm and is responsible for maintaining the position of accessory nuclei in hymenopteran oocytes (1995)
    Springer
    Development genes and evolution 205 (1995), S. 54-61 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Oogenesis ; Cytoskeleton ; Accessory nuclei ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Oocytes of hymenopterans are equipped with peculiar organelles termed accessory nuclei. These organelles originate from the germinal vesicle (oocyte nucleus) and gather preferentially at the anterior pole. To gain insight into the mechanism of uneven (asymmetrical) distribution of accessory nuclei, the organization of the microtubule cytoskeleton in the oocytes of two hymenopterans Chrysis ignita and Cosmoconus meridionator has been studied. It is shown that during late previtellogenesis two networks of microtubules are present along the contact zone between the oocyte and enveloping follicular epithelium. The external one is associated with belt desmosomes connecting neighbouring follicular cells. The internal network is composed of randomly orientated microtubules and separates transparent, organelle-free periplasm from the endoplasm. All cellular organelles and the germinal vesicle are localized in the endoplasm. Accessory nuclei are accumulated in the anterior endoplasm; they always lie in direct contact with the subcortical network. Treatment with colchicine results in the disappearance of the periplasm as well as in the redistribution of cellular organelles including accessory nuclei. Presented findings suggest that subcortical microtubules play an important role in the positioning of accessory nuclei throughout the ooplasm.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00188843
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  • 12
    Digitale Medien
    Digitale Medien
    Die hämatopoietische Stammzelle des Menschen Funktion und Morphologie* (1995)
    Springer
    Der Pathologe 16 (1995), S. 1-10 
    Details
    ISSN: 1432-1963
    Schlagwort(e): Schlüsselwörter Hämatopoietische Stammzellen ; CD 34+-Progenitorzellen ; Morphologie ; Ultrastruktur ; Antigenität ; Funktion ; Key words Haematopoietic stem cells ; CD 34+ progenitor cells ; Morphology ; Ultrastructure ; Antigen expression ; Function
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary Pluripotential haematopoietic stem cells and their progeny, the so-called committed precursor cells, i. e., progenitor cells which are already lineage-restricted, may be identified by the membrane-bound expression of CD 34. In accordance with this peculiar property it became possible to enrich and characterize primitive precursor cells by using different methods of cell separation techniques, which involved fluorescence staining or ferro-magnetic particles bound to CD 34 antibodies. Recently conducted studies demonstrate that CD 34-positive (CD 34+) stem cells of the peripheral blood represent a relatively uniform cell population with almost round nuclei, a finely dispersed chromatin pattern and a small portion of weakly basophilic cytoplasm. From the cytological viewpoint they resemble so-called large stimulated lymphocytes (virocytes). Ultrastructural studies are compatible with a paucity of organelles and a lymphoid character of these progenitors. In comparison, the stem cell population, derived from the bone marrow consists of more heterogeneous elements. These are generally larger and reveal an admixture of fairly immature as well as more differentiated cells, sharing bean-shaped or indented nuclei with prominent nucleoli and a more extended cytoplasm. CD 34+ progenitors from the peripheral blood and those from the bone marrow display a co-expression of CD 43 (MT1) and CD 45 (LCA). Furthermore, different subpopulations exhibit – dependent on their origin (blood/bone marrow) and to a various extent – lineage-restricted markers like CD 33, CD 38, CD 61, CD 20, CD 11a/c, glycophorin C und CD 15 (LeuM 1). The recently developed immuno- and ferromagnetic enrichment methods for CD 34+ progenitor cells are considered innovative tools for modern oncology. These techniques play an important role in the treatment of haematological malignancies and advanced tumours in the context of autologous and, although so far rarely applied, heterologous stem cell transplantation procedures.
    Notizen: Zusammenfassung Hämatopoietische Stammzellen, d. h. Progenitorzellen, die bereits in Richtung einer bestimmten Zellreihe festgelegt sind, lassen sich immunzytochemisch durch Nachweis der membranständigen Expression von CD 34 darstellen. Aufgrund dieser Eigenschaft ist es möglich geworden, Vorläuferzellen durch unterschiedliche Zellseparationsverfahren anzureichern und genauer zu charakterisieren. Neuere Untersuchungen zeigen, daß CD 34-positive (CD 34+-) Stammzellen des Blutes einer relativ uniformen Zellpopulation angehören. Zytologisch deuten sie in Routinefärbungen Aspekte sog. lymphoider Reizformen bzw. Virozyten an. Ultrastrukturelle Untersuchungen bestätigen den relativ organellenarmen Charakter der Progenitorzellen. Vergleichsweise stellt sich die entsprechende Zellpopulation aus dem Knochenmark als wesentlich heterogeneres Zellgemisch dar. Sowohl die CD 34+-Stammzellen des Blutes wie des Knochenmarks weisen eine Expression von CD 43 (MT1) und CD 45 (LCA) auf. Weiterhin zeigen Subpopulationen in Abhängigkeit von ihrem Vorkommen (Peripherie/Knochenmark) und in unterschiedlicher Ausprägung linienspezifische Marker. Die kürzlich entwickelten, v. a. immunomagnetischen Anreicherungsverfahren für CD 34+-Stammzellen stellen bedeutende Perspektiven für die moderne Onkologie dar. Sie sind insbesondere für die Therapie hämatologischer Neoplasien und fortgeschrittener maligner Tumoren im Rahmen von Stammzelltransplantationen, von größter klinischer Bedeutung.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002920050070
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  • 13
    Digitale Medien
    Digitale Medien
    Ultrastructural characterization of apospory in Panicum maximum (1995)
    Springer
    Sexual plant reproduction 8 (1995), S. 197-204 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Apomixis ; Apospory ; Aposporous initial ; Aposporous embryo sac ; Ultrastructure ; Panicum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The nucellar ultrastructure of apomictic Panicum maximum was analyzed during the meiocytic stage and during aposporous embryo sac formation. At pachytene the megameiocyte shows a random cell organelle distribution and sometimes only an incomplete micropylar callose wall. The chalazal nucellar cells are meristematic until the tetrad stage. They can turn into initial cells of aposporous embryo sacs. The aposporous initials can be recognized by their increased cell size, large nucleus, and the presence of many vesicles. The cell wall is thin with few plasmodesmata. If only a sexual embryo sac is formed, the nucellar cells retain their meristematic character. The aposporous initial cell is somewhat comparable to a vacuolated functional megaspore. It shows large vacuoles around the central nucleus and is surrounded by a thick cell wall without plasmodesmata. In the mature aposporous embryo sac the structure of the cells of the egg apparatus is similar to each other. In the chalazal part of the egg apparatus the cell walls are thin and do not hamper the transfer of sperm cells. Structural and functional aspects of nucellar cell differentiation and aposporous and sexual embryo sac development are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00228937
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  • 14
    Digitale Medien
    Digitale Medien
    Aluminium causes nutrient imbalance and structural changes in the needles of Scots pine without inducing clear root injuries (1995)
    Springer
    Trees 9 (1995), S. 134-142 
    Details
    ISSN: 1432-2285
    Schlagwort(e): Pinus sylvestris L. ; Aluminium ; Nutrients ; Mycorrhiza ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The effects of aluminium chloride (AICI3) treatments (50 and 150 mg/l) on 3-year-old Scots pine (Pinus sylvestris L.) seedlings were studied in a sand culture during 2 growing periods in an open field experiment. Even by the end of the first growing period, a decline was observed in the concentrations of Ca, Mg and P within the needles, and of Ca and Mg in the roots. After the second growing period, increased N and K concentrations were observed in the needles of Al-treated seedlings. Both the needles and roots of Al-treated seedlings showed, after the second growing period, a decline in growth and increased concentrations of AI as the amount of AICI3 in the nutrient solution increased. Al-induced changes in needle structure were found to be symptomatic of a nutrient imbalance, particularly of Mg and P. Al-stress did not result in any observable changes in root anatomy or in the number of mycorrhizas. Scots pine proved to be rather resistant to Al-stress, indicating that direct Al-injuries are not likely in the field, though Al-stress may be a contributing factor in the formation of nutrient imbalances.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02418202
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  • 15
    Digitale Medien
    Digitale Medien
    Mitochondrial abnormalities of muscle tissue in mice with juvenile visceral steatosis associated with systemic carnitine deficiency (1995)
    Springer
    Virchows Archiv 426 (1995), S. 271-279 
    Details
    ISSN: 1432-2307
    Schlagwort(e): JVS mouse ; Systemic carnitine deficiency ; Mitochondrial abnormality ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract A mouse with juvenile visceral steatosis (the JVS mouse) has been recognized as a novel animal model for systemic carnitine deficiency. We examined cardiac, skeletal and smooth muscle cells in JVS and control mice by light and electron microscopy. Cardiac and skeletal muscle cells of these mice at 4 weeks of age exhibited a ragged-red appearance after trichrome staining. Electron microscopy, demonstrated increased numbers of mitochondria and lipid droplets in the cells. Compression or distortion of the myofibril bundles, primarily due to the increased number of mitochondria, suggests the possible existence of a functional disturbance of the cardiac and skeletal muscle. In the urinary bladder, only one or two large lipid droplets and slightly increased number of mitochondria were recognized in the perinuclear region of the smooth muscle cells. At 8 weeks of age, the mouse enzyme histochemistry specific for mitochondria, such as cytochrome c oxidase and succinic dehydrogenase, and oil red O staining, confirmed further increases in the number of mitochondria and lipid droplets in the heart. However, the accumulation of these organelles in the skeletal and smooth muscle cells was no greater than that noted in JVS mice at 4 weeks of age. In the cardiac muscle cells, autolysosomes or autophagic vacuoles containing electron-dense membranous, lamellar or whorled structures closely associated with mitochondria and pseudoinclusion bodies in the nucleus were recognized, and bundles of myofibrils were buried under numerous mitochondria, suggesting the existence of disturbed contractile function in the heart of JVS mice. These results indicate that this murine strain associated with systemic carnitine deficiency exhibits a generalized mitochondrial abnormality in the muscle system especially in the heart.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00191365
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  • 16
    Digitale Medien
    Digitale Medien
    Ultrastructural changes in the lung in Niemann-Pick type C mouse (1995)
    Springer
    Virchows Archiv 427 (1995), S. 77-83 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Niemann-Pick disease ; Mouse ; Lung ; Electron microscope ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The biochemical and morphological aspects of BALB/c mice with many features of the Niemann-Pick disease type C in man (NP-C mouse) have been studied extensively. However, the pulmonary pathology has not been studied extensively and we describe here some unique ultrastructural features of the lung in the NP-C mouse. Ultrastructurally, macrophages in younger mice contained osmiophilic dense granules and annulolamellar structures, but larger multilamellar concentric structures increased in the macrophages of older mice. In contrast, endothelial cells and type I pneumocytes showed membrane-bound bodies with dense granules and vesicular or vesiculogranular structures as well as amorphous materials. Type II pneumocytes were unremarkable throughout. Our study suggests that endothelial cells and type I pneumocytes are the major site of metabolic derangement resulting in pronounced morphological changes with granular and round membranous structures in the lungs of NP-C mouse. Alveolar macrophages with multilamellar concentric structures may be a result of disturbed disposal of surfactant material from type II pneumocytes rather than that from storage material of type I pneumocyte.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00203741
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  • 17
    Digitale Medien
    Digitale Medien
    Differences in synaptic output between excitatory and inhibitory motoneurons in a crayfish muscle (1995)
    Springer
    Cell & tissue research 280 (1995), S. 513-518 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: Axo-axonal synapse ; Neuromuscular synapse ; Motoneuron ; Ultrastructure ; Procambarus clarkii (Crustacea)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. A pair of antagonistic motoneurons, one excitatory and one inhibitory, innervates the distal accessory flexor muscle in the walking limb of the crayfish Pro- cambarus clarkii. The number and size of synapses formed by these two axons on the muscle fibers (neuromuscular synapses) and on each other (axo-axonal synapses) were estimated using thin-section electron microscopy. Although profiles of nerve terminals of the two axons occur in roughly equal proportions, the frequency of occurrence of neuromuscular synapses differed markedly: 73% were excitatory and 27% were inhibitory. However, inhibitory synapses were 4–5 times larger than excitatory ones, and consequently, the total contact areas devoted to neuromuscular synapses were similar for both axons. Axo-axonal synapses were predominantly from the inhibitory axon to the excitatory axon (86%), and a few were from the excitatory axon to the inhibitory axon (14%). The role of the inhibitory axo-axonal synapse is presynaptic inhibition, but that of the excitatory axo-axonal synapse is not known. The differences in size of neuromuscular synapses between the two axons may reflect intrinsic determinants of the neuron, while the similarity in total synaptic area may reflect retrograde influences from the muscle for regulating synapse number.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318355
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  • 18
    Digitale Medien
    Digitale Medien
    Evolution and ultrastructure of the bovine spermatogonia precursor cell line (1995)
    Springer
    Cell & tissue research 281 (1995), S. 249-259 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: Stem cells ; Testis ; PGP 9.5 ; Ultrastructure ; Tubular whole-mounts ; Bovine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. The spermatogonial stem cell line in prepubertal and adult bovine testis was studied by electron microscopy and protein gene product 9.5 immunohistochemistry. Three successive spermatogonia precursor cell configurations were observed. Small basal stem cells were found to possess a spherical shape and nuclei with two to three nucleoli. They were observed in prepubertal testes (25 and 30 weeks) and in low numbers during all the stages of the seminiferous epithelial cycle in the adult. Aggregated spermatogonia precursor cells are the dominating germ cell type in the 25-week-old and 30-week-old calf. In the adult seminiferous epithelium, they cause expansion of the basal tubular compartment as they form dense groups containing up to 15 cells. These groups are observed concomitantly with cycling A-spermatogonia and preleptotenes at the beginning of spermatocytogenesis. At the end of A-spermatogonia propagation, the aggregated spermatogonia precursor cells separate and intermingle with cycling A-spermatogonia. The spermatogonia precursor cells can later be found together with I-spermatogonia as members of an interconnected cellular network of medium-sized cells. When the I-spermatogonia divide to form the smaller B-spermatogonia, the precursor cells, which stay connected with the cycling spermatogonial population, pass through a growth phase. They can now be considered as committed spermatogonia precursor cells and are continuously being transformed into A1-spermatogonia to start a new round of spermatocytogenesis. Ultrastructurally, all members of the precursor cell line are similar. However, a number of features have been found to show a quantitative increase (endoplasmic reticulum, mitochondria) or to exhibit a rising degree of complexity (nucleolus) during the progression from basal stem cells to committed spermatogonia precursor cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00583394
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  • 19
    Digitale Medien
    Digitale Medien
    Evolution and ultrastructure of the bovine spermatogonia precursor cell line (1995)
    Springer
    Cell & tissue research 281 (1995), S. 249-259 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Stem cells ; Testis ; PGP 9.5 ; Ultrastructure ; Tubular ; Whole-mounts ; Bovine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The spermatogonial stem cell line in prepubertal and adult bovine testis was studied by electron microscopy and protein gene product 9.5 immunohistochemistry. Three successive spermatogonia precursor cell configurations were observed. Small basal stem cells were found to possess a spherical shape and nuclei with two to three nucleoli. They were observed in prepubertal testes (25 and 30 weeks) and in low numbers during all the stages of the seminiferous epithelial cycle in the adult. Aggregated spermatogonia precursor cells are the dominating germ cell type in the 25-week-old and 30-week-old calf. In the adult seminiferous epithelium, they cause expansion of the basal tubular compartment as they form dense groups containing up to 15 cells. These groups are observed concomitantly with cycling A-spermatogonia and preleptotenes at the beginning of spermatocytogenesis. At the end of A-spermatogonia propagation, the aggregated spermatogonia precursor cells separate and intermingle with cycling A-spermatogonia. The spermatogonia precursor cells can later be found together with I-spermatogonia as members of an interconnected cellular network of medium-sized cells. When the I-spermatogonia divide to form the smaller B-spermatogonia, the precursor cells, which stay connected with the cycling spermatogonial population, pass through a growth phase. They can now be considered as committed spermatogonia precursor cells and are continuously being transformed into A1-spermatogonia to start a new round of spermatocytogenesis. Ultrastructurally, all members of the precursor cell line are similar. However, a number of features have been found to show a quantitative increase (endoplasmic reticulum, mitochondria) or to exhibit a rising degree of complexity (nucleolus) during the progression from basal stem cells to committed spermatogonia precursor cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00583394
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  • 20
    Digitale Medien
    Digitale Medien
    Immunocytochemical characterization of a new marker of fibrous and reactive astrocytes (1995)
    Springer
    Cell & tissue research 283 (1995), S. 39-49 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: Mab 6.17 ; Reactive astrocyte ; Diencephalon ; Spinal cord ; Confocal microscopy ; Ultrastructure ; Rat (Sprague Dawley)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. A specific monoclonal antiserum (Mab 6.17) inducing a strong immunostaining of the neuromuscular junction has been used to detect the possible occurrence of the corresponding antigen throughout the intact or lesioned central nervous system of adult rats. In intact animals, 6.17-immunolabeling was essentially detected in astrocyte-like structures located in white matter fasciculi of the brain, such as the optic tract, corpus callosum, fornix, and in the white matter of the spinal cord. The astroglial nature of such 6.17-immunolabeled profiles was verified by performing double or triple immunofluorescent labeling with Mab 6.17 and with specific antisera against astrocytic markers, such as S100 protein, glial fibrillary acidic protein and vimentin. In the white matter, all the structures reactive to Mab 6.17 were also reactive to antibodies against S100 protein, glial fibrillary acidic protein and vimentin. On the other hand, astrocytes of the grey matter that were immunoreactive to S100 and glial fibrillary acidic protein but negative to vimentin, were devoid of 6.17-immunoreactivity. After lesions including stab wound through the diencephalon or transection of the spinal cord, a marked increase of 6.17-immunostaining was noted in the regions surrounding the lesions. In these regions, 6.17-immunolabeling was associated with S100-, GFAP- and vimentin-positive astrocytes constituting the glial scar. The ultrastructural localization of 6.17-immunoreactivity indicated that, similar to glial fibrillary acidic protein and vimentin, the recognized antigen was mainly associated with gliofilaments. These observations indicate that, in the central nervous system of adult rats, Mab 6.17 recognizes a molecule associated with gliofilaments, which is essentially associated to reactive astrocytes expressing high levels of vimentin.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410050510
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  • 21
    Digitale Medien
    Digitale Medien
    Ultrastructural and time-lapse observations of intraepithelial lymphocytes in the small intestine of the guinea pig: their possible role in the removal of effete enterocytes (1995)
    Springer
    Cell & tissue research 280 (1995), S. 491-497 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: Intestine ; small ; Intraepithelial lymphocytes ; Microcinematography ; Ultrastructure ; Guinea pig
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. In previous ultrastructural studies we have shown that at the tip of intestinal villi in guinea pigs, effete enterocytes are separated into two portions: a thin apical cytoplasm to be exfoliated into the lumen and a major basal portion to be ingested by lamina propria macrophages. During this process, intraepithelially disposed, large granular lymphocytes interdigitate with enterocytes in a complex manner. In the present study, the relation between the enterocytes and the lymphocytes in the villous epithelium of the guinea pig small intestine is described by use of transmission and scanning electron microscopy in an attempt to visualize the roles and activities of the lymphocytes more clearly. The lymphocytes project numerous pointed processes into effete enterocytes, even piercing them. Enterocytes are deeply indented or perforated, probably as a result of the encroaching lymphocyte processes. Some enterocytes are separated into apical and basal portions by numerous large excavations in the cytoplasm. These findings indicate that repeated perforating penetration of the lymphocytes induces cell cleavage. Supporting this supposition, our microcinematographic observations demonstrate the alternate protrusion and withdrawal of processes of lymphocytes. The processes advance with a pointed end, and subsequently, retract with a rounded end in a cycle of 8–18 seconds.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318353
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  • 22
    Digitale Medien
    Digitale Medien
    Ultrastructural studies of the myenteric plexus and smooth muscle in organotypic cultures of the guinea-pig small intestine (1995)
    Springer
    Cell & tissue research 280 (1995), S. 627-637 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: Myenteric plexus ; Smooth muscle ; Organotypic culture ; Ultrastructure ; Intestine ; small ; Guinea-pig
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. External muscle and myenteric plexus from the small intestine of adult guinea-pigs were maintained in vitro for 3 or 6 days. Myenteric neurons and smooth muscle cells from such organotypic cultures were examined at the electron-microscopic level. An intact basal lamina was found around the myenteric ganglia and internodal strands. Neuronal membranes, nuclei and subcellular organelles appeared to be well preserved in cultured tissues and ribosomes were abundant. Dogiel type-II neurons were distinguishable by their elongated electron-dense mitochondria, numerous lysosomes and high densities of ribosomes. Vesiculated nerve profiles contained combinations of differently shaped vesicles. Synaptic membrane specializations were found between vesiculated nerve profiles and nerve processes and cell bodies. The majority of nerve fibres were well preserved in the myenteric ganglia, in internodal strands and in bundles running between circular muscle cells. No detectable changes were found in the ultrastructure of the somata and processes of glial cells. Longitudinal and circular muscle cells from cultured tissue had clearly defined membranes with some close associations with neighbouring muscle cells. Caveolae occurred in rows that ran parallel to the long axis of the muscle cells. These results indicate that the ultrastructural features of enteric neurons and smooth muscle of the guinea-pig small intestine are well preserved in organotypic culture.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318365
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  • 23
    Digitale Medien
    Digitale Medien
    Seasonal changes in hepatocyte ultrastructure correlated with the cyclic synthesis of secretory proteins in the winter flounder (Pleuronectes americanus) (1995)
    Springer
    Cell & tissue research 281 (1995), S. 153-161 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Liver ; Ultrastructure ; Antifreeze ; Proteins ; Secretion ; Lipid ; Flounder, Pleuronectes americanus (Teleostei)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Liver tissue was sampled from flounder (Pleuronectes americanus) throughout the year with the intention of documenting changes in the ultrastructure coincident with the production and secretion of antifreeze proteins. In the winter, hepatocytes are dedicated to the production of these proteins and, in the female, also reproductive proteins. In both sexes, liver cells in the summer contain abundant lipid and glycogen stores. In the female, there is a conspicuous hepatocyte transformation from a fat-filled cell in the summer to one with well-developed rough endoplasmic reticulum in the winter. Large amounts of rough endoplasmic reticulum (11.2 mg/gm) were recovered after subcellular fractionation of female wintertime liver. The increased appearance of secretory organelles and the high number of nucleolar profiles observed in winter animals is consistent with the elevated demand for protein secretion and synthesis in both sexes. The fractional volumes occupied by lipid droplets and mitochondria were different when comparisons were made between sex and season. Females contained a greater volume of lipid than did males, and summer animals contained more lipid than those in winter.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00307969
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  • 24
    Digitale Medien
    Digitale Medien
    Glycosaminoglycans in porcine lung: an ultrastructural study using Cupromeronic Blue (1995)
    Springer
    Cell & tissue research 281 (1995), S. 473-483 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: Glycosaminoglycans ; Cupromeronic Blue ; Lung ; Connective tissue ; Ultrastructure ; Pig
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. Glycosaminoglycans (GAGs) are essential components of the extracellular matrix contributing to the mechanical properties of connective tissues as well as to cell recognition and growth regulation. The ultrastructural localization of GAGs in porcine lung was studied by means of the dye Cupromeronic Blue in the presence of 0.3 M MgCl2 according to Scott’s critical electrolyte concentration technique. GAGs were observed in locations described as follows. Pleura: Dermatan sulphate (DS) and chondroitin sulphate (CS) attached in the region of the d-band of collagen fibrils, interconnecting the fibrils; heparan sulphate (HS) at the surface of elastic fibers and in the basement membrane of the mesothelium and blood vessels. Bronchial cartilage: Abundant amounts of GAGs were observed in three zones: pericellular, in the intercellular matrix and at the perichondrial collagen. By enzyme digestion a superficial cartilage layer with predominantly CS could be distinguished from a deep zone with CS and keratan sulphate. The structure of the large aggregating cartilage proteoglycan was confirmed in situ. Airway epithelium: HS at the whole surface of cilia and microvilli and in the basement membrane of the epithelial cells. Alveolar wall: CS/DS at collagen fibrils, HS at the surface of elastic fibers and in the basement membranes of epithelium and endothelium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410050442
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  • 25
    Digitale Medien
    Digitale Medien
    Glycosaminoglycans in porcine lung: an ultrastructural study using Cupromeronic Blue (1995)
    Springer
    Cell & tissue research 281 (1995), S. 473-483 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Glycosaminoglycans ; Cupromeronic Blue ; Lung ; Connective tissue ; Ultrastructure ; Pig
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Glycosaminoglycans (GAGs) are essential components of the extracellular matrix contributing to the mechanical properties of connective tissues as well as to cell recognition and growth regulation. The ultrastructural localization of GAGs in porcine lung was studied by means of the dye Cupromeronic Blue in the presence of 0.3 M MgCl2 according to Scott's critical electrolyte concentration technique. GAGs were observed in locations described as follows. Pleura: Dermatan sulphate (DS) and chondroitin sulphate (CS) attached in the region of the d-band of collagen fibrils, interconnecting the fibrils; heparan sulphate (HS) at the surface of elastic fibers and in the basement membrane of the mesothelium and blood vessels. Bronchial cartilage: Abundant amounts of GAGs were observed in three zones: pericellular, in the intercellular matrix and at the perichondrial collagen. By enzyme digestion a superficial cartilage layer with predominantly CS could be distinguished from a deep zone with CS and keratan sulphate. The structure of the large aggregating cartilage proteoglycan was confirmed in situ. Airway epithelium: HS at the whole surface of cilia and microvilli and in the basement membrane of the epithelial cells. Alveolar wall: CS/DS at collagen fibrils, HS at the surface of elastic fibers and in the basement membranes of epithelium and endothelium.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00417864
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  • 26
    Digitale Medien
    Digitale Medien
    The larval development of lateral musculature in gilthead sea bream Sparus aurata and sea bass Dicentrarchus labrax (1995)
    Springer
    Cell & tissue research 280 (1995), S. 217-224 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Ultrastructure ; Muscle growth ; Hypertrophy ; Hyperplasia ; Histochemistry ; Fish ; Sparus aurata, Dicentrarchus labrax (Teleostei)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Fibre-type differentiation of the lateral musculature has been studied in Sparus aurata (L.) and Dicentrarchus labrax (L.) during larval development. Histochemical and ultrastructural techniques show two presumptive muscle layers and two germinative zones of presumptive myoblasts. At hatching, myotomal muscle consists of a monolayer of thin undifferentiated cells near the skin (first germinative zone) overlying another mono-layer of small diameter fibres extending hypaxially and epaxially away from the transverse septum. Below this, there is a much thicker, deep layer of fibres, generally large in diameter and polygonal in shape. The presumptive myoblasts are located between these two layers of fibres in the second germinative zone. Initially, the superficial and deep muscle fibres show high and low myosin ATPase activity, respectively. Both layers grow by generating new fibres from the two mentioned germinative zones. At the end of larval life, the superficial layer changes its histochemical profile from high to low myosin ATPase activity and, at the same time, intermediate or pink muscle fibres can be observed by oxidative activity (the NADH-TR reaction). Morphometric analysis shows a significant increase in mean fibre diameter during successive ages, as shown by the Student's t-test (hypertrophic growth). Skewness and kurtosis values of fibre diameters point to the generation of a new fibre population from the germinative zones (hyperplastic growth).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00307792
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  • 27
    Digitale Medien
    Digitale Medien
    Ultrastructural and time-lapse observations of intraepithelial lymphocytes in the small intestine of the guinea pig: their possible role in the removal of effete enterocytes (1995)
    Springer
    Cell & tissue research 280 (1995), S. 491-497 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Intestine, small ; Intraepithelial lymphocytes ; Microcinematography ; Ultrastructure ; Guinea pig
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract In previous ultrastructural studies we have shown that at the tip of intestinal villi in guinea pigs, effete enterocytes are separated into two portions: a thin apical cytoplasm to be exfoliated into the lumen and a major basal portion to be ingested by lamina propria macrophages. During this process, intraepithelially disposed, large granular lymphocytes interdigitate with enterocytes in a complex manner. In the present study, the relation between the enterocytes and the lymphocytes in the villous epithelium of the guinea pig small intestine is described by use of transmission and scanning electron microscopy in an attempt to visualize the roles and activities of the lymphocytes more clearly. The lymphocytes project numerous pointed processes into effete enterocytes, even piercing them. Enterocytes are deeply indented or perforated, probably as a result of the encroaching lymphocyte processes. Some enterocytes are separated into apical and basal portions by numerous large excavations in the cytoplasm. These findings indicate that repeated perforating penetration of the lymphocytes induces cell cleavage. Supporting this supposition, our microcinematographic observations demonstrate the alternate protrusion and withdrawal of processes of lymphocytes. The processes advance with a pointed end, and subsequently, retract with a rounded end in a cycle of 8–18 seconds.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318353
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  • 28
    Digitale Medien
    Digitale Medien
    Ultrastructural studies of the myenteric plexus and smooth muscle in organotypic cultures of the guinea-pig small intestine (1995)
    Springer
    Cell & tissue research 280 (1995), S. 627-637 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Myenteric plexus ; Smooth muscle ; Organotypic culture ; Ultrastructure ; Intestine, small ; Guinea-pig
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract External muscle and myenteric plexus from the small intestine of adult guinea-pigs were maintained in vitro for 3 or 6 days. Myenteric neurons and smooth muscle cells from such organotypic cultures were examined at the electron-microscopic level. An intact basal lamina was found around the myenteric ganglia and internodal strands. Neuronal membranes, nuclei and subcellular organelles appeared to be well preserved in cultured tissues and ribosomes were abundant. Dogiel type-II neurons were distinguishable by their elongated electron-dense mitochondria, numerous lysosomes and high densities of ribosomes. Vesiculated nerve profiles contained combinations of differently shaped vesicles. Synaptic membrane specializations were found between vesiculated nerve profiles and nerve processes and cell bodies. The majority of nerve fibres were well preserved in the myenteric ganglia, in internodal strands and in bundles running between circular muscle cells. No detectable changes were found in the ultrastructure of the somata and processes of glial cells. Longitudinal and circular muscle cells from cultured tissue had clearly defined membranes with some close associations with neighbouring muscle cells. Caveolae occurred in rows that ran parallel to the long axis of the muscle cells. These results indicate that the ultrastructural features of enteric neurons and smooth muscle of the guinea-pig small intestine are well preserved in organotypic culture.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318365
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  • 29
    Digitale Medien
    Digitale Medien
    Seasonal changes in hepatocyte ultrastructure correlated with the cyclic synthesis of secretory proteins in the winter flounder (Pleuronectes americanus) (1995)
    Springer
    Cell & tissue research 281 (1995), S. 153-161 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: Liver ; Ultrastructure ; Antifreeze ; Proteins ; Secretion ; Lipid ; Flounder ; Pleuronectes americanus (Teleostei)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. Liver tissue was sampled from flounder (Pleuronectes americanus) throughout the year with the in-tention of documenting changes in the ultrastructure coincident with the production and secretion of antifreeze proteins. In the winter, hepatocytes are dedicated to the production of these proteins and, in the female, also reproductive proteins. In both sexes, liver cells in the summer contain abundant lipid and glycogen stores. In the female, there is a conspicuous hepatocyte transformation from a fat-filled cell in the summer to one with well- developed rough endoplasmic reticulum in the winter. Large amounts of rough endoplasmic reticulum (11.2 mg/gm) were recovered after subcellular fractionation of female wintertime liver. The increased appearance of secretory organelles and the high number of nucleolar profiles observed in winter animals is consistent with the elevated demand for protein secretion and synthesis in both sexes. The fractional volumes occupied by lipid droplets and mitochondria were different when comparisons were made between sex and season. Females contained a greater volume of lipid than did males, and summer animals contained more lipid than those in winter.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00307969
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  • 30
    Digitale Medien
    Digitale Medien
    Ultrastructural characterization of the sexually dimorphic medial preoptic nucleus of male Japanese quail (1995)
    Springer
    Cell & tissue research 279 (1995), S. 517-527 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: Avian brain ; Preoptic nucleus ; Sexual behaviour ; Ultrastructure ; Sexual dimorphism ; Coturnix japonica (Aves ; Phasianiformes)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. The medial preoptic nucleus is a sexually dimorphic structure whose cytoarchitecture, afferent and efferent connections, and functions have been previously described. No detailed ultrastructural study has, however, been perfomed to date. Here we describe the ultrastructural organization of this important preoptic structure of the male quail. Neuronal cell bodies of the medial preoptic nucleus generally show extensive development of protein-synthesis-related organelles (rough endoplasmic reticulum, polysomes), and of secretory structures (Golgi complexes, secretory vesicles, dense bodies). Previous morphometrical studies at the light-microscopical level have demonstrated the presence of a medial and a lateral neuronal population distinguished by the size of their cell bodies (the medial neurons are smaller than the lateral neurons). The present ultrastructural investigation confirms the difference in size, but no difference has been observed in the ultrastructural organization of the neurons. In both the medial and the lateral part, the nucleus is characterized by a large variety of cell bodies, including some that, on the basis of their ultrastructure, can be considered as putative peptidergic neurons. Close contacts are frequently observed between adjacent cell bodies that are normally arranged in clusters. Various types of synaptic endings are also present, suggesting a rich supply of nerve fibers. A few glial cells are scattered within the nucleus. In view of the crucial role of this region in regulating quail sexual behavior, the large heterogeneity of neurons and of afferent nervous fibers suggest that this region might have an important role in the integration of information arriving from different brain regions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410050311
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  • 31
    Digitale Medien
    Digitale Medien
    Fine structural study of interstitial cells associated with the deep muscular plexus of the rat small intestine, with special reference to the intestinal pacemaker cells (1995)
    Springer
    Cell & tissue research 282 (1995), S. 129-134 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Small intestine ; Pacemaker ; Interstitial cell ; Ultrastructure ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Two types of interstitial cells have been demonstrated in close association in the deep muscular plexus of rat small intestine, by electron microscopy. Cells of the first type are characterized by a fibroblastic ultrastructure, i.e. a well-developed granular endoplasmic reticulum, Golgi apparatus and absence of the basal lamina. They form a few small gap junctions with the circular muscle cells and show close contact with axon terminals containing many synaptic vesicles. They may play a role in conducting electrical signals in the muscle tissue. Cells of the second type are characterized by many large gap junctions that interconnect with each other and with the circular muscle cells. Their cytoplasm is rich in cell organells, including mitochondria, granular endoplasmic reticulum and Golgi apparatus. They show some resemblance to the smooth muscle cells and have an incomplete basal lamina, caveolae and subsurface cisterns. However, they do not contain an organized contractile apparatus, although many intermediate filaments are present in their processes. They also show close contacts with axon terminals containing synaptic vesicles. These gap-junction-rich cells may be regular components of the intestinal tract and may be involved in the pacemaking activity of intestinal movement.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00319139
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  • 32
    Digitale Medien
    Digitale Medien
    Ultrastructural study of the presence of vasoactive intestinal polypeptide and serotonin in mucosal nerve fibres and endocrine cells of the intestine of goldfish (Carassius auratus) and tilapia (Oreochromis mossambicus) (1995)
    Springer
    Cell & tissue research 283 (1995), S. 143-150 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: Vasoactive intestinal polypeptide (VIP) ; Serotonin ; Ultrastructure ; Immunogold label ; Mucosal nerves ; Goldfish ; Carassius auratus ; Tilapia ; Oreochromis mossambicus (Teleostei)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. In order to establish a possible role of vasoactive intestinal polypeptide (VIP) and serotonin as (neuro)transmitters involved in the regulation of fish intestinal epithelium, we studied the presence of VIP and serotonin at the ultrastructural level in the intestinal mucosa of tilapia and goldfish. A low percentage of varicosities near the basal membrane of the tilapia intestinal epithelium was found to label for VIP or for serotonin, whereas in the goldfish, this percentage was much higher. The varicosities usually contained large granular and small clear vesicles. Immunogold labeling indicated that serotonin and VIP were localized in the large granular vesicles. Unlabeled large granular vesicles and small clear vesicles were usually also present in varicosities with serotonin- or VIP-labeled vesicles. In the goldfish, the serotonin-labeled varicosities were close to the epithelial cells, and direct contacts between serotonin-labeled nerve fibres and epithelial cells could sometimes be visualized. However, synaptic membrane specializations were never observed. In tilapia, the distance between the VIP- or serotonin-labeled varicosities and the epithelial cells was large (more than 2 μm).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410050522
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  • 33
    Digitale Medien
    Digitale Medien
    Fine structural study of interstitial cells associated with the deep muscular plexus of the rat small intestine, with special reference to the intestinal pacemaker cells (1995)
    Springer
    Cell & tissue research 282 (1995), S. 129-134 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: Small intestine ; Pacemaker ; Interstitial cell ; Ultrastructure ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. Two types of interstitial cells have been demonstrated in close association in the deep muscular plexus of rat small intestine, by electron microscopy. Cells of the first type are characterized by a fibroblastic ultrastructure, i.e. a well-developed granular endoplasmic reticulum, Golgi apparatus and absence of the basal lamina. They form a few small gap junctions with the circular muscle cells and show close contact with axon terminals containing many synaptic vesicles. They may play a role in conducting electrical signals in the muscle tissue. Cells of the second type are characterized by many large gap junctions that interconnect with each other and with the circular muscle cells. Their cytoplasm is rich in cell organells, including mitochondria, granular endoplasmic reticulum and Golgi apparatus. They show some resemblance to the smooth muscle cells and have an incomplete basal lamina, caveolae and subsurface cisterns. However, they do not contain an organized contractile apparatus, although many intermediate filaments are present in their processes. They also show close contacts with axon terminals containing synaptic vesicles. These gap-junction-rich cells may be regular components of the intestinal tract and may be involved in the pacemaking activity of intestinal movement.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00319139
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  • 34
    Digitale Medien
    Digitale Medien
    Differences in synaptic output between excitatory and inhibitory motoneurons in a crayfish muscle (1995)
    Springer
    Cell & tissue research 280 (1995), S. 513-518 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Axo-axonal synapse ; Neuromuscular synapse ; Motoneuron ; Ultrastructure ; Procambarus clarkii (Crustacea)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract A pair of antagonistic motoneurons, one excitatory and one inhibitory, innervates the distal accessory flexor muscle in the walking limb of the crayfish Procambarus clarkii. The number and size of synapses formed by these two axons on the muscle fibers (neuromuscular synapses) and on each other (axo-axonal synapses) were estimated using thin-section electron microscopy. Although profiles of nerve terminals of the two axons occur in roughly equal proportions, the frequency of occurrence of neuromuscular synapses differed markedly: 73% were excitatory and 27% were inhibitory. However, inhibitory synapses were 4–5 times larger than excitatory ones, and consequently, the total contact areas devoted to neuromuscular synapses were similar for both axons. Axo-axonal synapses were predominantly from the inhibitory axon to the excitatory axon (86%), and a few were from the excitatory axon to the inhibitory axon (14%). The role of the inhibitory axo-axonal synapse is presynaptic inhibition, but that of the excitatory axo-axonal synapse is not known. The differences in size of neuromuscular synapses between the two axons may reflect intrinsic determinants of the neuron, while the similarity in total synaptic area may reflect retrograde influences from the muscle for regulating synapse number.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318355
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  • 35
    Digitale Medien
    Digitale Medien
    Ultrastructural localisation of NADPH-diaphorase in the chick thymic medulla (1995)
    Springer
    Cell & tissue research 279 (1995), S. 405-409 
    Details
    ISSN: 1432-0878
    Schlagwort(e): NADPH-diaphorase ; Nitric oxide ; Thymic medulla ; Ultrastructure ; Chick
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Nicotinamide-adenine-dinucleotide phosphate-diaphorase positive cells in the chick thymus were studied at the electron-microscopic level. The formazan, a marker for the enzyme nitric oxide synthase, labelled cystic, undifferentiated, endocrine-like and myoid cells in the medulla. Some lymphoid and reticulo-epithelial cells were also lightly labelled. The reaction product was predominantly bound to the membranes of the endoplasmic reticulum in all the cells labelled and also to the nuclear envelope and outer membrane of mitochondria. The Golgi apparatus and the plasma membrane were free of the reaction product.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318498
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  • 36
    Digitale Medien
    Digitale Medien
    Ultrastructural localisation of NADPH-diaphorase in the chick thymic medulla (1995)
    Springer
    Cell & tissue research 279 (1995), S. 405-409 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: NADPH-diaphorase ; Nitric oxide ; Thymic medulla ; Ultrastructure ; Chick
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. Nicotinamide-adenine-dinucleotide phosphate-diaphorase positive cells in the chick thymus were studied at the electron-microscopic level. The formazan, a marker for the enzyme nitric oxide synthase, labelled cystic, undifferentiated, endocrine-like and myoid cells in the medulla. Some lymphoid and reticulo-epithelial cells were also lightly labelled. The reaction product was predominantly bound to the membranes of the endoplasmic reticulum in all the cells labelled and also to the nuclear envelope and outer membrane of mitochondria. The Golgi apparatus and the plasma membrane were free of the reaction product.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410050297
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  • 37
    Digitale Medien
    Digitale Medien
    Ultrastructural characterization of the sexually dimorphic medial preoptic nucleus of male Japanese quail (1995)
    Springer
    Cell & tissue research 279 (1995), S. 517-527 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Avian brain ; Preoptic nucleus ; Sexual behaviour ; Ultrastructure ; Sexual dimorphism ; coturnix japonica (Aves, Phasianiformes)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The medial preoptic nucleus is a sexually dimorphic structure whose cytoarchitecture, afferent and efferent connections, and functions have been previously described. No detailed ultrastructural study has, however, been perfomed to date. Here we describe the ultrastructural organization of this important preoptic structure of the male quail. Neuronal cell bodies of the medial preoptic nucleus generally show extensive development of protein-synthesis-related organelles (rough endoplasmic reticulum, polysomes), and of secretory structures (Golgi complexes, secretory vesicles, dense bodies). Previous morphometrical studies at the light-microscopical level have demonstrated the presence of a medial and a lateral neuronal population distinguished by the size of their cell bodies (the medial neurons are smaller than the lateral neurons). The present ultrastructural investigation confirms the difference in size, but no difference has been observed in the ultrastructural organization of the neurons. In both the medial and the lateral part, the nucleus is characterized by a large variety of cell bodies, including some that, on the basis of their ultrastructure, can be considered as putative peptidergic neurons. Close contacts are frequently observed between adjacent cell bodies that are normally arranged in clusters. Various types of synaptic endings are also present, suggesting a rich supply of nerve fibers. A few glial cells are scattered within the nucleus. In view of the crucial role of this region in regulating quail sexual behavior, the large heterogeneity of neurons and of afferent nervous fibers suggest that this region might have an important role in the integration of information arriving from different brain regions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318164
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  • 38
    Digitale Medien
    Digitale Medien
    Immunogold labelling of estradiol receptor in MCF7 cells (1995)
    Springer
    Cell & tissue research 279 (1995), S. 445-452 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: Estradiol receptor ; Breast cancer cells ; Cell culture ; Ultrastructure ; Electron microscopy ; Immunohistochemistry ; Human
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. The distribution of estradiol receptor in serial sections of estradiol-deprived and estradiol-stimulated MCF7 cells was studied by using mouse monoclonal antibodies reacting with different domains of the receptor and goat-antimouse IgG/6 nm gold. In the nucleus and the cytoplasm of estradiol-deprived cells, the receptor was detected by all three monoclonals (13H2, HT 65 and MA1-310). The antibodies 13H2 and MA1-310 detected receptor associated to the microfilament bundles in the cytoplasm. Higher densities of antireceptor attachment to the nuclear areas were accompanied by a reduction in the attachment to the cytoplasm after estradiol stimulation of the cells. The results confirm earlier observations on the presence of cytoplasmic estrogen receptor in estradiol-deprived cells and support the premise of an es- tradiol-induced translocation of this ligand-dependent transcription regulator.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410050303
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  • 39
    Digitale Medien
    Digitale Medien
    Immunogold labelling of estradiol receptor in MCF7 cells (1995)
    Springer
    Cell & tissue research 279 (1995), S. 445-452 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Estradiol receptor ; Breast cancer cells ; Cell culture ; Ultrastructure ; Electron microscopy ; Immunohistochemistry ; Human
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The distribution of estradiol receptor in serial sections of estradiol-deprived and estradiol-stimulated MCF7 cells was studied by using mouse monoclonal antibodies reacting with different domains of the receptor and goat-antimouse IgG/6 nm gold. In the nucleus and the cytoplasm of estradiol-deprived cells, the receptor was detected by all three monoclonals (13H2, HT 65 and MA1-310). The antibodies 13H2 and MA1-310 detected receptor associated to the microfilament bundles in the cytoplasm. Higher densities of antireceptor attachment to the nuclear areas were accompanied by a reduction in the attachment to the cytoplasm after estradiol stimulation of the cells. The results confirm earlier observations on the presence of cytoplasmic estrogen receptor in estradiol-deprived cells and support the premise of an estradiol-induced translocation of this ligand-dependent transcription regulator.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00318156
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  • 40
    Digitale Medien
    Digitale Medien
    Cells of the photoreceptor line in the pineal organ of an adult marsupial, Didelphis albiventris (1995)
    Springer
    Cell & tissue research 282 (1995), S. 363-366 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Pineal organ ; Pinealocytes ; Secretory rudimentary photoreceptors ; Ultrastructure ; Didelphis albiventris (Marsupialia)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract We report the presence of atypical pinealocytes as components of epiphyseal follicles in the adult South American opossum Didelphis albiventris. Their main characteristic is a bulbous-shaped apical cytoplasmic extension which protrudes towards the follicular lumen among the microvilli and cilia of neighbouring ependymal cells. They resemble the photoreceptor-like pinealocytes of sauropsids and developing photoreceptors in the retina of newborn mammals. Morphological characteristics enable us to classify them as cells of the receptor line.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00319126
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  • 41
    Digitale Medien
    Digitale Medien
    Cells of the photoreceptor line in the pineal organ of an adult marsupial, Didelphis albiventris (1995)
    Springer
    Cell & tissue research 282 (1995), S. 363-366 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words: Pineal organ ; Pinealocytes ; Secretory rudimentary photoreceptors ; Ultrastructure ; Didelphis albiventris (Marsupialia)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. We report the presence of atypical pinealo-cytes as components of epiphyseal follicles in the adult South American opossum Didelphis albiventris. Their main characteristic is a bulbous-shaped apical cytoplasmic extension which protrudes towards the follicular lumen among the microvilli and cilia of neighbouring ependymal cells. They resemble the photoreceptor-like pinealocytes of sauropsids and developing photoreceptors in the retina of newborn mammals. Morphological characteristics enable us to classify them as cells of the receptor line.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410050487
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  • 42
    Digitale Medien
    Digitale Medien
    Comparative anatomy and ultrastructure of active and dormant vascular cambium in rhizome ofBotrychium ternatum (1995)
    Springer
    Journal of plant research 108 (1995), S. 149-159 
    Details
    ISSN: 1618-0860
    Schlagwort(e): Anatomy ; Botrychium ternatum ; Rhizome ; Ultrastructure ; Vascular cambium
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Vascular cambium ofBotrychium ternatum rhizome varied according to age, position and season was studied by light and electron microscopy. Cambium at the 6th internode (6-year-old cambium) had the greatest number of active cambial cells in August and September, thus it was in the most active stage. The active cells were characterized by the presence of a large vacuole, few storage materials such as starch grains within plastids or lipid droplets, a thin tangential wall; and various cell organelles in the thin peripheral layer of cytoplasm. When the 6-year-old cambium reached its dormant season after November, the dormant cells were filled with numerous storage materials and had few cell organelles. Our observations suggested that the initiation and cessation of cambial activity may be correlated with the annual life cycle of this plant: the vegetative and reproductive leaves began to emerge in June and July, respectively, and the sporophyll withered in November after the spore dispersal. Most cambial cells at the 10th internode, which remained in a dormant state throughout the year, were filled with numerous storage materials. Our results indicated that the activity of vascular cambium in the 10th internode was determinate.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02344339
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  • 43
    Digitale Medien
    Digitale Medien
    Cellular changes during the acquisition of embryogenic potential in isolated pollen grains ofNicotiana tabacum (1995)
    Springer
    Protoplasma 186 (1995), S. 220-230 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Embryogenesis ; In vitro culture ; Isolated pollen ; Nicotiana tabacum ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We used electron microscopical techniques to study ultrastructural changes during the acquisition of embryogenic competence in immature pollen grains ofNicotiana tabacum, isolated at the early- or mid-bicellular stage and cultured in vitro under starvation conditions. Cytoplasmic and nuclear changes during the starvation treatment are reported. Dedifferentiation of plastids, dilation of the wall of the generative cell, the appearance of a large vacuole, loss of nuclear pores in the vegetative nucleus, changes in chromatin and nucleolar structure, and a decrease in the size of the nucleolus were observed. We suggest that these events are the first step in the switch from generative to vegetative generation during pollen embryogenesis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01281332
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  • 44
    Digitale Medien
    Digitale Medien
    Accumulation of vismione A in regenerated plants ofVismia guianensis DC (1995)
    Springer
    Protoplasma 189 (1995), S. 9-16 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Metabolite accumulation ; Vismia guianensis ; Callus cultures ; Plant regeneration ; Ultrastructure ; Histochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The accumulation and tissue localization of antitumoral vismione A in the in vitro regenerated plants ofVismia guianensis DC. were investigated. Chemical and light and electron-microscope analyses revealed that vismione A, detected as phenolic black globules in the vacuoles, was accumulated in the leaf, mainly in the palisade, and in small amounts in the primary body of the stem (epidermis and first cortical layer). Vismione A is neither present in the secretory cavities and ducts of the leaf nor in the secretory ducts of the stem. In the leaves of the regenerated plants, the amount of vismione A reached 0.5% FW, compared to 0.1% in the leaves of the parent plant. The optimization of the in vitro regeneration of plants was obtained in MS medium enriched with BAP (1 ppm). The best results for the rooting of regenerated plants were achieved with MS medium containing half-strength salts and 10−5 MIBA.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01280287
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  • 45
    Digitale Medien
    Digitale Medien
    Low-density lipoproteins inhibit histamine and NaNO2 relaxations of the coronary vasculature and reduce contractile function in isolated rat hearts (1995)
    Springer
    Heart and vessels 10 (1995), S. 249-257 
    Details
    ISSN: 1615-2573
    Schlagwort(e): LDL ; Rat heart ; Ultrastructure ; Coronary vasculature ; Contractile function
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In the present study we examined the action of native and oxidized low-density lipoproteins (LDL) on coronary vascular and cardiac function and ultrastructure in rat hearts perfused isovolumically in the Langendorff mode. Responses of the coronary resistance vessels to the endothelium-dependent vasodilator, histamine, and the endothelium-independent vasodilator, NaNO2, were measured together with contractile function (rate-pressure product) before and after perfusion for 20 min with native — or oxidized-LDL at a concentration of 100 µg protein/ml. Ultrastructural damage was assessed via electron microscopy of perfusion-fixed heart specimens. When compared to findings in untreated, control hearts, both native and oxidized LDL significantly reduced the responsiveness of the coronary resistance vessels to histamine and NaNO2, by about 50%. The rate-pressure product was decreased more by oxidized-LDL (41%) than by native-LDL (26%). Electron microscopy showed no ultrastructural abnormalities in the vasculature or myocytes of control hearts. The administration of both native- and oxidized-LDL caused distortion of endothelial cells, increased levels of pinocytotic vesicles in both endothelial and smooth muscle cells, detachment of blood vessels from surrounding tissue, and some regions of myocyte injury with evidence of mitochondrial injury and fluid accumulation. Our results show that both native- and oxidized-LDL are toxic to the isolated heart preparation. They inhibit coronary vascular responsiveness to vasodilators, reduce contractile function, and produce damage to cardiac ultrastructure.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01744904
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  • 46
    Digitale Medien
    Digitale Medien
    Usefulness of electron microscopy in the diagnosis of cardiac sarcoidosis (1995)
    Springer
    Heart and vessels 10 (1995), S. 275-278 
    Details
    ISSN: 1615-2573
    Schlagwort(e): Sarcoidosis ; Heart ; Endomyocardial biopsy ; Epithelioid cell ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A 49-year-old man with cardiac sarcoidosis is presented. He suffered from congestive heart failure, and left ventricular asynergy and reduced function was evident by echocardiogram and left ventriculogram. A light microscopic examination of the endomyocardial biopsy revealed nonspecific myocarditis without giant cells or noncaseating granulomas. Under an electron microscope, however, several epithelioid cells were found in the specimen. The serum level of lysozyme was elevated. The patient had a past history of sarcoidosis of the eyes and lungs 22 years previously. Cardiac diseases presenting epithelioid cells other than sarcoidosis were clinically ruled out. Thus, the diagnosis of cardic sarcoidosis was made based on both clinical and ultrastructural findings, and corticosteroid therapy was initiated. In the second biopsy, performed 4 months later, a noncaseating granuloma was found. Generally, the incidence of histological diagnosis of cardiac sarcoidosis by light microscopy is relatively low in endomyocardial biopsy specimens. The present case suggests that the addition of an ultrastructural examination may improve the diagnostic usefulness of the endomyocardial biopsy in cardiac sarcoidosis, since electron microscopy can clearly identify the presence of even one epithelioid cell.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01744907
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  • 47
    Digitale Medien
    Digitale Medien
    Ultrastructural studies on the embryo sac ofViscum minimum I. Megasporogenesis (1995)
    Springer
    Protoplasma 185 (1995), S. 93-105 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Embryo sac ; Embryogenesis ; Megasporogenesis ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Changes taking place during megasporogenesis of a mistletoe (Viscum minimum) were examined at both light and electron microscopy levels. No distinct ovules, integuments, or ovarian cavity are present at any stage of development. The multicellular archesporium originates in the center of a solid ovary. Several functional megasporocytes are developed from the archesporial cells, either adjacent to each other or separated by unspecialized cells. The megasporocyte is much larger than surrounding cells, is invested by a thick wall, and possesses a large nucleus and amyloplasts. Although plasmodesmata are absent even between the adjacent megasporocytes, cells enter meiosis simultaneously. Following meiosis a linear tetrad is formed. Double and treble linear tetrads are frequently observed. The development of the embryo sac conforms to the monosporic or Polygonum type of megasporogenesis. However, the bisporic or Allium type of development is occasionally observed in preparations. Factors determining the pattern of development are discussed. As in other plant species which follow the monosporic type of development, only one functional megaspore cell undergoes further development while others degenerate. Unlike the healthy functional megaspore cell, the degenerating cells have large starch grains and electron-dense cytoplasm. At a later stage of development, the degraded cells are absorbed by the surrounding tissue.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01272757
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  • 48
    Digitale Medien
    Digitale Medien
    Endoplasmic reticulum as a storage site for allergenic proteins in pollen grains of several Oleaceae (1995)
    Springer
    Protoplasma 187 (1995), S. 111-116 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Allergenic protein ; Oleaceae ; Pollen ; Endoplasmic reticulum ; Immuno-localization ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The ultrastructure of mature pollen grains of several Oleaceae species (Olea europaea, Fraxinus excelsior, Syringa vulgaris, Ligustrum vulgare, andForsythia suspensa) was studied and the immunolocalization of Ole e I, the major allergen of olige pollen, was determined by immunogold labelling. The five Oleaceae pollens studied here showed different intensities of labelling. The Ole e I allergen was localized throughout the rough endoplasmic reticulum. The absence of gold particles in other cell compartments, such as nuclei, pastids, mitochondria, dictyosomes, lipid bodies, and cell wall, as well as the absence of labelling in control preparations, indicate the specificity of immunolocalization. We conclude that endoplasmic reticulum of the mature pollen grain is a storage site for allergenic proteins and is probably also involved in their synthesis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01280238
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  • 49
    Digitale Medien
    Digitale Medien
    Electron microscopic studies onNosema mesnili Paillot (Microsporidia: Nosematidae) infecting the Malpighian tubules ofPieris canidia larva (1995)
    Springer
    Protoplasma 186 (1995), S. 142-148 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Pieris canidia ; Nosema mesnili ; Microsporidia ; Lepidoptera ; Pieridae ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The ultrastructure of a microsporidiumNosema mesnili found in the Malpighian tubules ofPieris canidia is described. The life cycle includes meronts, sporonts, sporoblasts, and spores, with typical diplokaryon in each stage. The first two stages are amorphous forms with the former having a thinner cell wall. The spore has 11 coils of the polar filament. This protozoan is a chronic pathogen to its insect host and might have potential as a biological control agent.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01281324
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  • 50
    Digitale Medien
    Digitale Medien
    Ultrastructure of microsporogenesis and microgametogenesis inArabidopsis thaliana (L.) Heynh. ecotype Wassilewskija (Brassicaceae) (1995)
    Springer
    Protoplasma 185 (1995), S. 7-21 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Arabidopsis thaliana ; Microgametogenesis ; Microsporogenesis ; Pollen development ; Tapetal cells ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The process of microsporogenesis and microgametogenesis was studied at the ultrastructural level in wild-typeArabidopsis thaliana ecotype Wassilewskija to provide a basis for comparison with nuclear male-sterile mutants of the same ecotype. From the earliest stage studied to mature pollen just prior to anther dehiscence, microsporocyte/microspore/pollen development follows the general pattern seen in most angiosperms. The tapetum is of the secretory type with loss of the tapetal cell walls beginning at about the time of microsporocyte meiosis. Wall loss exhibits polarity with the tapetal protoplasts becoming located at a distance from the inner tangential walls first, followed by an increase in distance from the radial walls beginning at the interior edge and progressing outward. The inner tangential and radial tapetal walls are completely degenerated by the microspore tetrad stage. Unlike other members of the Brassicaceae that have been studied, the tapetal cells ofA. thaliana Wassilewskija also lose their outer tangential walls, and secretion occurs from all sides of the cells. Exine wall precursors are secreted from the tapetal cells in a process that appears to involve dilation of individual endoplasmic reticulum cisternae that fuse with the tapetal cell membrane and release their contents into the locule. Following completion of the exine, the tapetal cell plastids develop membranebound inclusions with osmiophilic and electron-transparent regions. The plastids undergo ultrastructural changes that suggest breakdown of the inclusion membranes followed by release of their contents into the locule prior to the complete degeneration of the tapetal cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01272749
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  • 51
    Digitale Medien
    Digitale Medien
    Early cellular events during induction of carrot explants with 2,4-D (1995)
    Springer
    Protoplasma 185 (1995), S. 28-36 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Carrot hypocotyl explant ; Flow cytometry ; Somatic embryogenesis ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The cellular events occurring in carrot hypocotyl explants during long-term and pulse treatment with 2,4-D were followed using different techniques (light and transmission electron microscopy, flow cytometry, PCNA staining). Different morphogenetic pathways were induced under the various experimental conditions. Nevertheless, in the explants the activated cells were the same (provascular cells) and they showed very similar structural and ultrastructural changes. The long-term treatment with 2,4-D induced rapid re-activation of the cell cycle.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01272751
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  • 52
    Digitale Medien
    Digitale Medien
    Cellular changes during heat shock induction and embryo development of cultured microspores ofBrassica napus cv. Topas (1995)
    Springer
    Protoplasma 185 (1995), S. 106-112 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Brassica napus ; Embryogenesis ; Heat shock ; Induction ; Microspore embryogenesis ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Brassica napus cv. Topas microspores, isolated and cultured near the time of the first pollen mitosis and subjected to a heat treatment of 24 h, can be induced to develop into haploid embryos. This is a study of microspore structure during induction and embryo determination. Early during the 32.5 °C incubation period the nucleus moved away from the edge of the cell, and granules, 30 to 60 nm in diameter, appeared in the mitochondria and as a cluster in the cytoplasm. Cells divided symmetrically and at the end of the heat treatment, acquired the features of induced bicellular structures described previously. The features persisted as the cells divided randomly within the exine for 4–7 days following heat induction. Multicellular structures released from the exine underwent periclinal divisions resulting in protoderm differentiation of the globular embryo, thus determining embryo development. The cytoplasm of early heart-stage embryos contains abundant polyribosomes. Non-embryogenic development was indicated by large accumulations of starch and/or lipid and thickened cell walls or an unorganized pattern of cell division following release of the multicellular structures from the exine. Embryogenesis is discussed in terms of induction, embryo determination and development.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01272758
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  • 53
    Digitale Medien
    Digitale Medien
    Disturbance of the secretory pathway inMicrasterias denticulata by tunicamycin and cyclopiazonic acid (1995)
    Springer
    Protoplasma 189 (1995), S. 173-179 
    Details
    ISSN: 1615-6102
    Schlagwort(e): Cyclopiazonic acid ; Golgi apparatus ; Micrasterias ; Secretory pathway ; Tunicamycin ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Both tunicamycin, an inhibitor of N-linked glycosylation of proteins, and cyclopiazonic acid, which inhibits the Ca2+-dependent ATPase in the ER, influence the secretory pathway at the ER level and lead to a cessation of cell growth inMicrasterias. Electron microscopical investigations reveal that the mode of action of the two inhibitors differs. While tunicamycin treatment results in a disintegration of the Golgi bodies into small vesicles, cyclopiazonic acid prevents products being supplied from the ER, resulting in the dilatation of ER cisternae and a reduction in the number of Golgi cisternae, combined with a loss of dictyosomal activity. The disturbed cell wall formation under tunicamycin indicates that N-linked glycosylation of proteins is required for normal cell growth inMicrasterias. Moreover, our studies reveal that changes in cytoplasmic free calcium concentration, as a consequence of ATPase inhibition in the ER by cyclopiazonic acid, may inhibit wall material secretion by interrupting the normal ER-dictyosome association.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01280171
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  • 54
    Digitale Medien
    Digitale Medien
    Studies on turfgrass snow mold caused byTyphula ishikariensis. II. Microscopical observation of infected bentgrass leaves (1995)
    Springer
    Mycoscience 36 (1995), S. 179-185 
    Details
    ISSN: 1618-2545
    Schlagwort(e): Turfgrass snow mold ; Typhula ishikariensis ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Light and transmission electron microscopy revealed thatTyphula ishikariensis penetrated into bentgrass leaves either through cuticles or stomata either by single hyphae or infection cushions formed on host surfaces. Time course study on infected leaves showed that penetration through stomatal subsidiary cells and their adjacent cells seemed to occur earlier than that through epidermal cells located farther from stomata. More than 30% of epidermal cells were infected by 10 days after inoculation. When hyphae penetrated through an intact cuticle of epidermal cells, they seemed to dissolve host cell walls enzymatically at penetration sites. Physical pressure also seemed to be involved in penetration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02268555
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  • 55
    Digitale Medien
    Digitale Medien
    Plasticity of gonad development in hermaphroditic sparids: ovotestis ontogeny in a protandric species, Lithognathus mormyrus (1995)
    Springer
    Environmental biology of fishes 43 (1995), S. 255-267 
    Details
    ISSN: 1573-5133
    Schlagwort(e): Gonadogenesis ; Early germ cell ; Teleost ; Ultrastructure ; Fish
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Synopsis Heterosexual gonad development in a sparid species, Lithognathus mormyrus, was studied by histological and cytological examination, during the first three years of life. Gonad bisexuality is achieved after two months of development, according to the cytological dynamics known in sparids. In one-year-old fishes, a variability in the gonad morphology of the juvenile is shown: three different types of ovotestis have been identified within the same cohort: ovotestes with testicular prevalence (25%), testicular and ovarian equivalence (20%), and ovarian prevalence (55%). This morphological variability of the juvenille ovotestes was consistent with the histological analysis of the sexual structure of the adult stock at the first sexual maturity, which constituted 55.5% of functional males (stemming from the first types of ovotestis) and 44.5% of primary females (from the third type). The plasticity of sexual expression in sparids is emphasized, revealing the potentialities of the ovotestis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00005857
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  • 56
    Digitale Medien
    Digitale Medien
    Inverted ductal papilloma of minor salivary gland origin: morphological aspects and cytokeratin expression (1995)
    Springer
    European archives of oto-rhino-laryngology and head & neck 252 (1995), S. 370-373 
    Details
    ISSN: 1434-4726
    Schlagwort(e): Salivary gland tumors ; Inverted ductal papilloma ; Ultrastructure ; Cytokeratin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Ultrastructural features and cytokeratin expression of inverted ductal papillomas of minor salivary gland origin were studied. Under the electron microscope, an increased number of desmosomes and mucus-like granules in some cells were the most striking features. Immuno-histochemical study revealed that tumor cells displayed strongly positive reactions with cytokeratins 13 and 14, and less strong reactions with cytokeratins 7, 8, 18 and 5D3. These results support the hypothesis that an inverted ductal papilloma can be derived from the proximal portion of a salivary gland excretory duct.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00178280
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  • 57
    Digitale Medien
    Digitale Medien
    Determination of viability of cryopreserved cartilage grafts (1995)
    Springer
    European archives of oto-rhino-laryngology and head & neck 252 (1995), S. 30-34 
    Details
    ISSN: 1434-4726
    Schlagwort(e): Cartilage grafting ; Cryopreservation ; Cell biology ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Although transplantation of preserved cartilage has assumed a role of great importance in reconstructive surgery, there are many divergent and contradictory opinions with regard to the outcome of cryopreserved cartilage. This study was formulated to assess the functional state of chondrocytes after cryopreservation. Freeze injury and survival were studied using the trypan blue dye exclusion test, functional assay for cell adhesion and transmission electron microscopy. The methods applied clearly proved that a greater part of the cartilage cells was irreversibly damaged by cryopreservation. Findings demonstrated that cryopreserved cartilage remained non-viable and was not ablt to originate new cartilage. Thus, such cartilage will be reconstruction of parts of the skeleton subject to mechanical stress. The feasibility of cryopreservation techniques for providing vital cartilage substitutes needs further evaluation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00171437
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  • 58
    Digitale Medien
    Digitale Medien
    Masthead (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995) 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280101
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  • 59
    Digitale Medien
    Digitale Medien
    Tripodal Triamidostannates as Building Blocks in the Generation of Sn - M-Bonded Heterobimetallics (M = Fe, Ru) (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 29-34 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Tripodal ligands ; Triamidostannates ; Metal-metal bonds ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: By in situ lithiation of the trifunctional amines H3CC(CH2NHSiMe3)3, PhC(CH2NHSiMe3)3, and HC{SiMe2NH(p-Tolyl)}3 and subsequent reaction with SnCl2 the corresponding triamidostannates were obtained. These were coupled with CpM(CO)2Cl (M = Fe, Ru) to yield the M - Sn-bonded heterobimetallics 9-14 of which H3CC(CH2NSiMe3)3SnFe(CO)2Cp (9) was characterized by a single-crystal X-ray structure analysis. Of the in situ-generated amidostannates only [HC{SiMe2N(p-Tolyl)}3Sn][Li(THF)3] (8) could be isolated as a uniform product and characterized analytically and spectroscopically.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280105
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  • 60
    Digitale Medien
    Digitale Medien
    The Structures of [X2Y—N—YX2]+ Cations (X = F, Cl; Y = S, Se). A Comparison of X-ray and ab Initio Studies[1] (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 35-40 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Selenium-nitrogen compounds ; Sulfur-nitrogen compounds ; Calculations, ab initio ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The structures of cationic species of the series [X2Y—N—YX2]+ (X = F, Cl; Y = S, Se) have been computed ab initio using all electron treatments for first-row elements and sulfur and quasi-relativistic pseudopotentials for Se and Cl. Splitvalence basis sets with polarization and diffuse functions were employed. The MP2 results for the (non-isostructural!) cations [Cl2Se—N—SeCl2]+ (1: Cs) and [F2S—N—SF2]+ (2: C2v) are in excellent agreement with the experimental (X-ray) observations. Both structures represent local minima. A deeper minimum for either of the cations is represented by another C2v isomer which for crystal lattice energy reasons is stable in the isolated state only. The geometries of the hitherto unknown species [Cl2S—N—SCl2]+ (3) and [F2Se—N—SeF2]+ (4) have been assessed by ab initio HF calculations. In analogy to 2, cations 3 and 4 are predicted to prefer C2v symmetry. Therefore, 1 exhibits unusual structural features. According to strictly localized natural bond orbital analysis (NBO), the central nitrogen atoms in 1 and 2 possess two lone pairs of electrons (LP: one sp hybrid and one p orbital). The relatively short Se—N and S—N bond distances in 1 (1.741-1.760 Å) and 2 (1.551 Å) can best be attributed to LP(N)→s̰*(Y—X) negative hyperconjugation (1: Y = Se, X = Cl; 2: Y = S, X = F).
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280106
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  • 61
    Digitale Medien
    Digitale Medien
    Die fördernde Rolle von Phosphinoester-Liganden bei der Synthese neutraler Carben-, Vinyliden- und Allenyliden-Ruthenium(II)-KomplexeHerrn Professor Hubert Schmidbaur zum 60. Geburtstag gewidmet. (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 49-62 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Ruthenium(II) complexes, octahedral ; Phosphino esters as mono- and bidentate ligands ; Fluxional behaviour ; Carbene complexes ; Vinylidene complexes ; Allenylidene complexes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Vinylidene Transition-Metal Complexes, XXXV[1].  -  The Supporting Role of Phosphino Ester Ligands for the Synthesis of Neutral Carbene, Vinylidene and Allenylidene Ruthenium(II) ComplexesThe reaction of [RuCl2(PPh3)3] (1) with the phosphino esters iPr2P(CH2)nCO2R (2-4) leads to complete (n = 1; R = CH3, C2H5) or partial (n = 2; R =CH3) displacement of the PPh3 ligands and formation of the octahedral ruthenium(II) complexes [RuCl2{k2(P,O)-iPr2PCH2CO2R}2] (5, 6) and [RuCl2(PPh3){k(P)-iPr2PCH2CH2CO2Me}{k2(P,O)-iPr2PCH2CH2CO2Me}] (7). Treatment of 5 with LiBr and LiI affords the dibromo- and diiodoruthenium derivatives 8 and 9. While compound 5 reacts with CO and SO2 by cleavage of one Ru - O bond to yield the 1:1 adducts [RuCl2(L){k(P)-iPr2PCH2CO2Me}{k2(P,O)-iPr2PCH2CO2Me}] (10, 11), the reaction of the dibromo derivative 8 with CO in solution gives the dicarbonyl complex [RuBr2(CO)2{k(P)-iPr2PCH2CO2Me}2](13). If CO is passed over 8 in the solid state, the corresponding monocarbonyl compound 14 is formed. The hydridoruthenium(II) complex 16, which is obtained from equimolar amounts of [RuHCl(CO)(PiPr3)2] (15) and 2, reacts with HC≡CMe by insertion to give the vinyl derivative [RuCl{E - CH=CHMe}(CO)(PiPr3){k2(P,O)-iPr2CH2CO2Me}] (17). Treatment of 5 with HC̊' (R' = H, Me, tBu, Ph) and of 6, 8, 9 with HC≡CPh affords upon photochemical activation the octahedral vinylidene complexes [RuX2-(=C=CHR){k(P)-iPr2PCH2CO2R}{k2(P,O)-iPr2PCH2CO2R}] (18-21 and 23-25) in good to excellent yield. At room temperature, these compounds (with the exception of 25) are highly fluxional in solution. From 31P-NMR measurements, the free energies of activation ΔG
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280108
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  • 62
    Digitale Medien
    Digitale Medien
    Reaktionen von R2Al—AlR2 (R = CH(SiMe3)2) mit Trimethylsilylazid  -  Insertion in die Al—Al-Bindung und Abbau zum trimeren Dialkylaluminiumazid (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 81-85 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Aluminium-aluminium bond ; Insertion of trimethylsilyl azide ; Trimeric dialkylaluminium azide ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Reactions of R2Al—AlR2 (R = CH(SiMe3)2) with Trimethylsilyl Azide  -  Insertion into the Al—Al Bond and Formation of a Trimeric Dialkylaluminium AzideTetrakis[bis(trimethylsilyl)methyl]dialuminium(4) (1) reacts with trimethylsilyl azide under insertion of one nitrogen atom into the Al—Al bond. As shown by NMR spectra and crystal structure the product contains three and four coordinated Al atoms due to the coordination of the α-nitrogen atom of the azide group to one of the Al atoms. An electronically delocalized N3-system is formed with a N—N bond length of 132.0 pm and a bond order of 1.5 for both N—N bonds. With an excess of trimethylsilyl azide further reaction is observed only under mild irradiation conditions with an exchange of the azide group between Si and Al and formation of Me6Si2 and the dialkylaluminium azide 3, which is better synthesized by the reaction of Me3Si—N3 with Cl—Al[CH(SiMe3)2]2. The sterically highly shielded aluminium azide 3 is a trimer in the solid state showing a non-planar 12-membered Al3N9 heterocycle with short N—N bonds (114 pm).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280112
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  • 63
    Digitale Medien
    Digitale Medien
    Transition-Metal Complexes with the Novel Scorpionate Ligand Dihydrobis-(tetrazolyl)borate: Synthesis and Characterization of Infinite Two-Dimensional Metal-Ligand Frameworks and One-Dimensional Water SubstructuresDedicated to Professor Dr. Herbert Schumann on the occassion of his 60th birthday. (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 323-328 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Poly(azolyl)borates, metal complexes of ; Bis(tetrazolyl)borate, metal complexes of ; Metal-nitrogen coordination ; Coordination polymers ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Dihydrobis(tetrazolyl)borate metal compounds of the composition [M(L)2{μ-H2B(CHN4)2}2]n for M = Mn, Fe, Co, Zn, Cd with L = H2O and for M = Cu with L = NH3 are obtained from metal salts and K[H2B(CHN4)2]. Single-crystal X-ray studies reveal the formation of two-dimensional rhombic grid sheets through the bridging action of the bis(tetrazolyl)borate ligands. Each metal atom is octahedrally coordinated with two trans L ligands and four H2B(CHN4)-2 nitrogen donors. Two additional, hydrogen-bonded water molecules occupy the rhombic openings in the compounds with M = Mn, Fe, Co, Zn, and Cd. The water of crystallization is held in place through hydrogen bonding from the water ligands and to the nitrogen atoms to give a substructure of parallel kinked water chains. Temperature-variable magnetic measurements show a Curie-Weiss behavior for the paramagnetic complexes with M = Mn, Fe, Co, and Cu.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280402
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  • 64
    Digitale Medien
    Digitale Medien
    New Organophosphorus Ligands: Cyclopropanation and Other Reactions of Cumulenes Bearing Diphenylphosphanyl Substituents (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 365-371 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Cumulenes ; Butadienes ; Vinylcyclopropane ; Vinylidenecyclopropane ; Bicyclopropyl, phosphanyl-substituted ; Cyclopropanation ; Phosphane ligands ; Phosphane chalcogenides ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Hydrophosphorylation of 1,4-bis(diphenylphosphanyl)butadiyne with diphenylphosphane leads to the butadiene (Ph2P)2C=CH—CH=C(PPh2)2 (1). Treatment of 1 with dimethylsulfonium methylide gives the vinylcyclopropane (Ph2P)2C=CH—CH(CH2)C(PPh2)2 (2). Compound 2 reacts with aqueous hydrogen peroxide, elemental sulfur, or selenium to afford the tetrachalcogenides (Ph2XP)2C=CH—CH(CH2)C(PXPh2)2 with X = O (3), X = S (4), X = Se (5), respectively. While the tetraphosphane 1 and the vinyl-cyclopropane compound 2 cannot be converted into a bis-(cyclopropyl) compound with an excess of Me2S=CH2, the tetrasulfide 4 readily affords a mixture of (1R,1′R)-/(1S,1′S)-and meso-2,2,2′,2′-tetrakis(diphenylthiophosphinyl)-1,1′-bicyclopropyl (6, 7) in good yield. Treatment of 1,1,4,4-tetrakis-(diphenylphosphanyl)butatriene with dimethylsulfonium methylide leads to the vinylidenecyclopropane (Ph2P)2C=C=C(CH2)C(PPh2)2 (8). Compound 8 is converted into its tetrasulfide (Ph2SP)2C=C=C(CH2)C(PSPh2)2 (9) by treatment with elemental sulfur. The crystal structures of 1, 2, 4, 7, and 8 have been determined by single-crystal X-ray diffraction.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280408
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  • 65
    Digitale Medien
    Digitale Medien
    Mono- und Diferriophosphane und -thioxophosphoraneHerrn Professor Dr. Ekkehard Lindner zum 60. Geburtstag gewidmet. (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 413-416 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Ferriophosphanes ; Ferriophosphoranes ; Thioxophosphane ligand ; Decarbonylation reaction ; Sulfurization ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Mono- and Diferriophosphanes and -thioxophosphoranesHerrn Professor Dr. Ekkehard Lindner zum 60. Geburtstag gewidmet.The substitution of organic substituents in phosphanes or thioxophosphoranes by the 17-electron fragments CpFe-(CO)2 (—Fp) leads to isolobal ferriophosphanes or -thioxophosphoranes. The mono- and diferriophosphanes FpnPPh3-n [n = 1 (3), 2 (4)] are obtained by deprotonation of the mono- and diferriophosphonium salts [FpnPPh3-nH]X [n = 1 (1), 2 (2)] with DBU. They are oxidized by sulfur giving the mono- and diferriothioxophosphoranes FpnPPh3-n(S) [n = 1 (5), 2 (6)]. Sulfide 5 arises also from the reaction of CpFe(CO)2Cl and Ph2PH(S)/DBU. The one-sided decarbonylation reaction of 6 leads to FpFp′PPh(S) (7, Fp′ = CpFeCO). The Fp substituents (17 electrons) in 3-7 coordinate as one-electron donors to the PhnP- or PhnP(S) units (n = 1, 2). The bridging functions in 4 and 6 are hitherto unknown. The molecular structures of the complexes 5-7 were determined by X-ray structure analyses.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280413
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  • 66
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    Digitale Medien
    About some Electrophilic Substitution Reactions with [(CF3S)3C+][AsF-6] (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 435-436 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Trifluoromethylthio group ; Carbenium ions ; Diphenylmethane ; Dyes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Tris(trifluoromethylthio)carbenium hexafluoroarsenate (1) reacts with N,N-dimethylaniline and anisole to form the corresponding diphenylmethanes 2, 3 with the SCF3 group at the methine carbon atom. During the reaction of 1 with benzene, compounds such as C6H5C(SCF3)3 and C6H5SCF3 are formed along with benzophenone, a product of hydrolysis of the diphenylmethane compound.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280417
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  • 67
    Digitale Medien
    Digitale Medien
    Synthesis and Structure of the First Dimetalated Diphosphane Disulfide [(η5-C5Me5)(CO)2FeP(H)(S)]2 (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 441-442 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Diphosphane disulfides ; Metallophosphoranes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The first transition metal derivative meso-[(η5-C5Me5)(CO)2FeP(H)(S)]2 (2) of the unknown diphosphane disulfide [PH2(S)]2 results from treatment of (η5-C5Me5)(CO)2FePH2 (1) with 1.5 equivalents of elemental sulfur. Compound 2 was characterized by means of spectroscopy (IR, 31P, 31P{1H}, 13C{1H}, 1H NMR) as well as X-ray diffraction analysis.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280419
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  • 68
    Digitale Medien
    Digitale Medien
    Preparation and Molecular Structures of Tetrahydrofuran, Diethylene Diglycol Dimethyl Ether and 18-Crown-6 Complexes of Strontium and Barium TetrahydridoborateDedicated to Prof. Dr. Nils Wiberg on the occasion of his 60th birthday. (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 455-460 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Strontium bis(tetrahydridoborate)-2 tetrahydrofuran, chain polymer of ; Strontium bis(tetrahydridoborate)-bis(diglyme) ; Barium bis(tetrahydridoborate)-bis(diglyme) ; Strontium bis(tetrahydridoborate)-1,4,7,13,16-hexaoxacyclooctadecane ; Metal-hydrogen-boron bridges ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The strontium and barium tetrahydridoborate complexes M(BH4)2 · 2 diglyme and M(BH4)2 · 18-crown-6 (M = Sr, Ba) have been prepared from the solvates M(BH4)2 · 2 THF by ligand displacement. 11B-NMR and IR data reveal strongly polar bonding of the BH4 groups to the metal centers, and X-ray structural analyses of the diglyme and crown ether compounds show molecular units in which the BH4 group is in contact via three H atoms with the metal center. In contrast, M(BH4)2 · 2 THF compounds are chain polymers in the solid state, and each metal center is surrounded by 2 THF molecules in trans position and four BH4- groups each of which forms bridges with two metal centers. Estimations of the effective radius for the BH4 group indicate a high polarity for the M-BH4 interaction.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280504
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  • 69
    Digitale Medien
    Digitale Medien
    Photochemische Reaktionen von Übergangsmetall-Organyl-Komplexen mit Olefinen, 1312. Mitteilung: Lit.Photochemisch induzierte [5+2],homo[5+21-Cycloaddition von 3-Hexin an Tricarbonyl(η5-2,4-cycloheptadien-l-yl)mangan (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 515-518 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Manganese ; Cycloheptadienyl ; Alkyne ; [5+2],homo[5+2] Cycloadditions ; Tricyclo[5.3.1.04,10]undeca-2,5-dien-11-yl ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Photochemical Reactions of Transition Metal Organyl Complexes with Olefins, 1312. Mitteilung: Lit. . - Photochemically Induced [5+2], homo[5+2] Cycloaddition of 3-Hexyne to Tricarbonyl(η 5-2,4-cycloheptadien-1-yl)manganeseTricarbonyl(η5-2,4-cycloheptadien-1-yl)manganese (1) reacts upon UV irradiation in hexane at 243 K with two equivalents of 3-hexyne (2) in successive [5+2],homo[5+2] cycloadditions to give tricarbonyl(η2:2:1-1,2,3,11-tetraethyltricyclo-[5.3.1.04,10]undeca-2,5-dien-11-yl)manganese (3). Its crystal and molecular structure was determined by an X-ray diffraction analysis, in solution it was studied also by IR and NMR spectroscopy.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280513
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  • 70
    Digitale Medien
    Digitale Medien
    Masthead (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995) 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280601
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  • 71
    Digitale Medien
    Digitale Medien
    1,4,2-Diazaphospholothiazoles and -pyridines by a Hantzsch-Type Condensation Using Chloromethyldichlorophosphane (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 581-587 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Anellated azaphospholes ; Hantzsch-type [3 + 2] cyclocondensation ; Chloromethyldichlorophosphane ; Regioselectivity ; 31P-, 1H-, 13C-NMR spectra ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The [3 + 2] cyclocondensation of 2-amino-1,3-thiazoline, 2-aminopyridines, 2- and 4-aminopyrimidines, 2-aminopyrazine, and 2-aminoquinoline with chloromethyldichlorophosphane in the presence of triethylamine yields regiospecifically 5,6-dihydrothiazolo[2,3-e][1,4,2]diazaphosphole (3), 1,4,2-diazaphospholo[4,5-α]pyridines (12), 1,4,2-diazaphospholo[4,5-α]pyrimidines (15), 1,4,2-diazaphospholo[4,5-e]pyrimidine (17), 1,4,2-diazaphospholo[4,5-α]pyrazine (19), and [1,4,2]diazaphospholo[4,5-α]quinoline (22), respectively. Using 2-amino-1,3-thiazole (4) and 2-aminobenzothiazoles 8, we obtained mixtures of the 1,5- and 4,5-anellated 1,4,2-diazaphospholes 5/6, 9a/10a and 9b/10b, while in the case of the methyl derivative 8c only the [1,4,2]diazaphospholo[5,4-b][1,3]benzothiazole 10c was formed. In the reaction of 2-aminothiazole and 2-aminopyrazine with Chloromethyldichlorophosphane the bis(diazaphospholo)-substituted chloromethylphosphanes 7 and 20 could be detected. The new anellated 1,4,2-diazaphospholes are colorless to pale yellow crystalline moisture-sensitive solids.
    Zusätzliches Material: 6 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280610
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  • 72
    Digitale Medien
    Digitale Medien
    Reactions at Silicon-Silicon Bonds, V. Selective Trichlorosilylation of Alkyl(diorganylamino)chlorophosphanes with Hexachlorodisilane or with Trichlorosilane/Triethylamine. - Two Routes to New Functional Trichlorosilylphosphanes (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 615-619 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Reductive silylation ; Aminochlorophosphanes ; Silylphosphanes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reaction of alkyl(diorganylamino)chlorophosphanes R(R2′N)PCl 1 (1a: R = tBu, R′ = Et, 1b: R = iPr, R′ = iPr; 1c: R = iPr, R′ = Ph) with hexachlorodisilane, afforded alkyl(diorganylamino)trichlorosilylphosphanes R(R2′N)PSiCl3 2 (2a: R = tBu, R′ = Et; 2b: R = iPr, R′ = iPr; 2c: R = iPr, R′ = Ph) and silicon tetrachloride. An intermediate formed in the reaction of 1b with hexachlorodisilane, the adduct iPr(iPr2N)(Cl)P-Si(Cl)3-SiCl3 (3b = 1b · Si2Cl6), was detected by 31P- and 29Si-NMR spectra that indicate pentacoordinated silicon bound to tetracoordinated phosphorus and tetracoordinated silicon. Trichlorosilylphosphanes 2 are also available from 1 under very mild conditions by reductive trichlorosilylation with trichlorosilane in the presence of triethylamine. Compounds 2 were identified analytically, by mass spectroscopy, multinuclear NMR, and an X-ray structure determination of 2c.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280614
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  • 73
    Digitale Medien
    Digitale Medien
    Reactions of Complex Ligands, LXIVPart LXIII: Ref.. Synthesis of 5,5′-Diphenyl-2,2′-bifuran, a Biaryl Compound with Remarkable Fluorescence Properties (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 641-643 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Carbene ligands ; Tungsten complexes ; 2,2′-Bifuran ; Copper coupling reaction ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The 2-oxacyclic α,β-unsaturated carbene complex 1 reacts with an excess of dimethylamine to give the diphenylbifuran 2. The structure of 2 was established by independent synthesis from 2-phenylfuran (4) via regioselective lithiation and transmetalation to zinc and tin organometallics 6a-c and final oxidative copper coupling reactions.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280618
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  • 74
    Digitale Medien
    Digitale Medien
    Synthesis of 2- and 3-Stannolenes via Addition of Trimethyltin Alkoxides to 3-Diethylboryl-4-ethyl-1,1-dimethylstannole (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 679-687 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Stannole, diethylboryl-substituted ; Trimethyltin alkoxides ; 2-, 3-Stannolenes, organometallic-substituted ; NMR, coupling constants, 2J(Sn,Sn), sign determination ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Trimethyltin alkoxides (2) react stereoselectively with 3-diethylboryl-4-ethyl-1,1-dimethylstannole (1) via addition of the Me3Sn group to C(2) to the C(2) = C(3) bond and a 1,2 shift of an ethyl group from boron to C(3) to give the 2-stannolenes 3. The molecular structure of 3f' [R = (S)-2-Bu] was determined by single-crystal X-ray analysis, confirming the cis positions of the Et(RO)B and the Me3Sn group. These 2-stannolenes 3 undergo, upon heating to ca. 80°C, facile rearrangement by irreversible allylic migration of the Et(RO)B group to the 3-stannolenes 4 in which the cis positions of the boryl and the stannyl group are retained. All 2-stannolenes (in contrast to the 3-stannolenes) are readily deprotoborylated to give the 3-stannolene 5. The structures of 3, 4, and 5 follow conclusively from 1H-, 11B-, 13C-, and 119Sn-NMR spectra. The negative sign of the geminal coupling constants 2J(SnSn) was determined in the case of 3, 4, and 5 by 2D 119Sn/1H heteronuclear shift correlations.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280705
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  • 75
    Digitale Medien
    Digitale Medien
    Synthesis of Structures of (Acyloxy)boranesDedicated to Prof. Dr. A. Schmidpeter on the occasion of his 65th birthday.Synthesis of Structures of (Acyloxy)boranes (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 751-762 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Trifluoroacyloxy-9-borabicyclo[3.3.1]nonane ; Pivaloyloxy-9-borabicyclo[3.3.1]nonane dimer ; Bis(9-borabicyclo[3.3.1]nonyl]oxalate ; Tetrakis(9-borabicyclo[3.3.1]nonyl)-dihydroxyoxalate ; Bis(9-borabicyclo[3.3.1]nonyl)-2,2-dimethylmalonate tetramer ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 9-Borabicyclo[3.3.1]nonane (9-BBNH) reacts with monocarboxylic acids to afford 9-(acyloxy)-9-borabicyclo[3.3.1]nonanes which are dimers in the solid state as shown by X-ray crystal structures of the benzoate and pivalate. More complex reactions were observed by allowing 9-BBNH to react with dicarboxylic acids in THF or monoglyme. Thus, (9-BBN)2 oxalate 3 contains a fully delocalized oxalate unit with equal C-O and B-O bond lengths. Traces of water convert it into the tetrakis(9-BBN) oxalate 5. A rather unusual structure is veryfied by 9-BBN 2,2-dimethylmalonate 7 which according to its molecular structure is a tetramer featuring a 32-membered ring system. In contrast, reactions of oxalic acid with thexylborane leads to reduction of the acid and formation of a bicyclic dioxaborolo-dioxaborolane 10. Several intermediates were detected by 11B-NMR spectroscopy as well as in reactions of BH3 · THF or BH3 · SMe2 with oxalic acid.  -  It follows from the present study that (acyloxy)boranes derived from dicarboxylic acids are strong Lewis acids with an unexpected variety of structural features.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280803
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  • 76
    Digitale Medien
    Digitale Medien
    A T-Shaped Selenenyl Halide: Synthesis and Characterisation of a Proposed Reaction Intermediate (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 741-742 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Selenenyl halides ; Nucleophilic substitution ; Complex intermediate ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The T-shaped selenenyl halide (1), which may be regarded as a model substance for the transition state in nucleophilic displacement at divalent chalcogen atoms, has been isolated and subjected to X-ray structure determination.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280715
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  • 77
    Digitale Medien
    Digitale Medien
    Zinc Complexes of Drugs Containing Nitrogen Heterocycles (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 779-785 
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    ISSN: 0009-2940
    Schlagwort(e): Zinc complexes ; Drug ligands ; Captopril ; Isoniazid ; Nalidixic acid ; Mercaptopurine ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Four drugs whose actions have a relation to the status of zinccontaining species in the human body were used as ligands in zinc complexes. Captopril (H2Cap) forms the compound [ZnCap] (1) presumed to be a coordination polymer with O and S coordination. Isoniazid, in the presence of zinc salts, is converted to 1,2-diisonicotinoyl hydrazide (H2Nih) which forms polymeric [Zn(Nih)NH3] (2) with trigonal-bipyramidal ZnO2N3 coordination. Nalidixic acid (HNal) and zinc perchlorate yield [Zn(HNal)2(H2O)2](ClO4)2 · 2 H2O (3) containing zinc in an octahedral ZnO6 environment. Mercaptopurine (H2Mer), in the presence of ammonia, forms [Zn(Mer)(NH3)2] . H2O (4) which is a coordination polymer containing tetrahedral ZnN4 units. The structures of [Zn(Nih)NH3], [Zn(HNal)2(H2O)2](ClO4)2 . 2 H2O, and [Zn(Mer)(NH3)2] . 2 H2O were determined diffractometrically.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280807
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  • 78
    Digitale Medien
    Digitale Medien
    Enantioselective Deprotonation of Benzyl Phosphates by Homochiral Lithium Amide Bases  -  Configurational Stability of Benzyl Carbanions with a Dialkoxyphosphoryloxy Substituent and Their Rearrangement to Optically Active α-Hydroxy Phosphonates (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 823-830 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Phosphate-phosphonate rearrangement ; Carbanions, benzylic, configurational stability of ; Phosphonaes Lithium amides, homochiral ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Benzyl dialkyl phosphates are deprotonated enantioselectively by homochiral lithium amides of isopropyl(1-phenylethyl)amine or bis(1-phenylethyl)amine. The short-lived benzylic carbanions formed are virtually configurationally stable relative to the rearrangement to optically active phenyl-hydroxymethylphosphonates. The enantiomeric excesses are up to 50%. The pro-(S) hydrogen is removed by amides having (S) configuration. Homochiral diethyl (S)-phenyl[D1]-methyl phosphate [(S)-16c] is deprotonated by both LDA and n-BuLi with a high primary kinetic isotope effect (kH/D ≍ 50) and isomerizes to the corresponding α-hydroxy phosphonate with an enantiomeric excess of up to 85%.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280814
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  • 79
    Digitale Medien
    Digitale Medien
    Tris(1,10-phenanthroline)iron(II) Complexes  -  Broad Variation of the Redox Potential by 4,7-Substitution at the Phenanthroline Ligands[1] (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 845-850 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Phenanthroline synthesis ; Tris(phenanthroline)iron(II) complexes ; Redox potential ; Cyclic voltammetry ; Electron transfer, outer-sphere ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The new 4,7-donor-substituted phenanthrolines 2a-h were synthesized and the corresponding tris(1,10-phenanthroline)iron(II) complexes 3a-h studied by cyclic voltammetry. In more detail three novel aza-crown ether-linked (phenanthroline)iron complexes were investigated, the redox potentials of which could be fine-tuned by the addition of group-Ia,IIa metal cations. All iron(II) complexes showed reversible waves at scan rates between 50 and 500 mV · s-1 and could be reversibly oxidized and reduced by chemical means.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280816
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  • 80
    Digitale Medien
    Digitale Medien
    Bis(cyclopentadienyl)methane-Bridged Dinuclear Complexes, 10Part 9: B. Stempfle, H. Werner, Gazz. Chim. Ital., 1995, 125, in press. The Bis(cyclopentadienyl)methane Link between Lewis Basic and Lewis Acidic Metal CentersDedicated to Prof. Dr. Herbert Schumann on the occasion of his 60th birthday. (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 877-881 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Bis(cyclopentadienyl)methane ; Heterobimetallic complexes ; Imido complexes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The mononuclear rhodium complexes [(C5H5CH2C5H4)-Rh(CO)2] (1) and [(C5H5CH2C5H4)Rh(PhC≡CPh)(PiPr3)] (2) readily react with nBuLi or TlOEt to yield the corresponding lithium salts 3 and 4 or thallium salts 5 and 6. The reaction of these salts with [(C5H5)Nb(NtBu)Cl2] (7) leads to the formation of the heterodinuclear compounds [{CH2(C5H4)2}-{Rh(CO)2}{(C5H5)Nb(NtBu)Cl}] (8) and [{CH2(C5H4)2}-{Rh(PhC≡CPh)(PiPr3)}{(C5H5)Nb(NtBu)Cl}] (9), respectively. Treatment of 3-6 with [Mo(NtBu)2Cl2] (10) gives the heterodinuclear Rh/Mo complexes [{CH2(C5H4)2}{Rh(CO)2}-{Mo(NtBu)2Cl}] (11) and [{CH2(C5H4)2}{Rh(PhC≡CPh)-(PiPr3)}{Mo(NtBu)2Cl}] (12). The analogous reaction of [Mo(NMes)2Cl2(DME)] (13) with 3-6 yields the corresponding complexes [{CH2(C5H4)2}{Rh(CO)2}{Mo(NMes)2Cl}] (14) and [{CH2(C5H4)2}{Rh(PhC≡CPh)(PiPr3)}{Mo(NMes)2Cl}] (15). From the monometallated ligand [(C5H5CH2C5H4)M] (M = Li: 16; M = Tl: 17) and the imidometal compounds 7, 10 and 13, the mononuclear complexes [(C5H5CH2C5H4)(C5H5)Nb-(NtBu)Cl] (18) and [(C5H5CH2C5H4)Mo(NR)2Cl] (R = tBu: 19; R = Mes: 20) have been obtained.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280905
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  • 81
    Digitale Medien
    Digitale Medien
    Addition von Hydrofullerid [C60H]- an koordinierte, ungesättigte Kohlenwasserstoffe: Bindung von Fulleren an Metallkomplexe über KohlenwasserstoffbrückenHerrn Professor Herbert Walter Roesky zum 60. Geburtstag gewidmet (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1059-1060 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Fullerene ; Hydrofulleride ; Manganese complex ; Rhenium complex ; Iron complexes ; Ruthenium complex ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Addition of Hydrofulleride [C60H]- to Coordinated, Unsaturated Hydrocarbons: Binding of Fullerene to Metal Complexes through Hydrocarbon BridgesHerrn Professor Herbert Walter Roesky zum 60. Geburtstag gewidmet.Hydrofulleride [C60H]- is added to the hydrocarbon ligands of the cationic complexes [(OC)5Re(η2-C2H4)]+, [(OC)3Mn-(η6-C6H6)]+, [(OC)3M(η5-C6H7)]+ (M = Fe, Ru), [(OC)3Fe(η5-C7H9)]+, and [(η5-C5H5)Fe(η6-C5H4CH2)]+.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951281017
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  • 82
    Digitale Medien
    Digitale Medien
    Controlled Conversion of the Transient 2-Mesityl-1,1-bis(trimethylsilyl)silene into a Tetrahydro-2,3-disilanaphthalene, a 1,2-Disilacyclobutane, or a 1,3-Disilacyclobutane (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1083-1088 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Silenes ; Silene dimerization ; 1,2-Disilacyclobutanes ; 1,3-Disilacyclobutanes ; 2,3-Disilanaphthalene, tetrahydro- ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Mesityl[tris(trimethylsilyl)silyl]methanol (1) reacts with strong bases with elimination of trimethylsilanolate according to a Peterson-type mechanism, the outcome of the reaction being dependent on solvent, temperature, and nature of the organometallic base applied. Thus, 1 was converted by treatment with MeLi in ether at -78°C to (E)-1,2,3,8a-tetra -hydro-1-mesityl-5,7,8a-trimethyl-2,2,3,3-tetrakis (trimethylsi-lyl)-2,3-disilanaphthalene (3), formally a [2 + 4] cyclodimer of the transient silene (Me3Si)2Si=CHMes (2). The reaction of 1 with PhMgBr in THF after some days resulted in the formation of (Z)-3,4-dimesityl-1,1,2,2-tetrakis(trimethylsilyl) -1,2-disilacyclobutane (6) as the main product besides small quantities of 3, the polysilane (Me3SiSi(SiMe3)2CH2Mes (10), and the alkoxysilane (Me3Si)3SiCH(Mes)OSi(Si-Me3)2CH2Mes (7). Compound 6, the formal [2 + 2] cycloadduct of 2, can also be obtained by thermal treatment of 3 and is considered to be the thermodynamically more stable silene dimer whereas 3 is the kinetically preferred product. At high LiBr concentrations in the reaction mixture 1 was converted by PhMgBr in THF to (E)-2,4-dimesityl-1,1,3,3-tetrakis(tri- methylsilyl)-1,3-disilacyclobutane (13) besides 6 and [bis(tri-methylsilyl)silyl]mesityl(trimethylsiloxy)methane (11). The unforeseen formation of 13 is discussed as proceeding via the silene-lithium bromide adduct (Me3Si)2Si(Br)CH(Li)Mes (12). In the absence of LiBr 1 was converted by MeLi in THF at -78°C to 11 and the trisilane (Me3Si)2Si(Me)CH2Mes (4b). Probable pathways of the formation of all new compounds are discussed. For 6 and 13 the results of the X-ray structural analyses are given.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951281105
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  • 83
    Digitale Medien
    Digitale Medien
    Metallkomplexe mit biologisch wichtigen Lisganden, LXXXLXXIX. Mitteilung: Lit.. (η3:η3-C10H16)Ru(IV)-Komplexe mit α-Aminocarboxylaten, α-Aminosäureestern und Peptidestern als Liganden (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1117-1125 
    Details
    ISSN: 0009-2940
    Schlagwort(e): 1,7-Dimethylocta-2,6-diene-1,8-diyl ; Ruthenium complexes ; α-Amino carboxylates ; α-Amino acid esters ; Peptide esters ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Metal Complexes Containing Biologically Important Ligands, LXXXLXXIX. Mitteilung: Lit. .  -  (η3:η3-C10H16)Ru(IV) Complexes with α-Amino Carboxylates, α-Amino Acid Esters, and Peptide Esters as LigandsReactions of the chloro-bridged bis(allyl) complex [(η3:η3-C10H16)Ru(Cl)(μ-Cl)]2 with α-amino carboxylates and α-amino acid esters afford the complexes (η3:η3-C10H16)(Cl)RuNH2CHRCO2 (2) and (η3:η3-C10H16)(Cl)2-RuNH2CHRCO2R′ (3). Abstraction of chloride from 3 by Ag+ gives the N,O-chelates [(η3:η3-C10H16)(Cl)RuNH2CHRCO2R′]+BF4 (4). Cysteine methyl ester forms the N,S-chelate complex (η3:η3-C10H16)(Cl)RuNH2CH(CO2CH3)CH2S (5), and with histidine methyl ester a dinuclear complex 6 with N,N-histidine bridge is obtained. Compound 3d with L-PheOEt as ligand was characterized by X-ray diffraction.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951281110
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  • 84
    Digitale Medien
    Digitale Medien
    [MeO(CH2CH2O)3(CH2)3C5Me4]FeCl: A Halfsandwich Iron (II) Chloride Complex of Remarkable Stability (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1135-1136 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Hemilabile ligands ; Cyclopentadienyl ligands, functionalised ; Iron compounds ; Halfsandwich complex ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Reaction of iron(II) chloride with one equivalent of [MeO-(CH2CH2O)3(CH2)3C5Me4]Li in THF yields the title halfsand-wich complex 1, which is stable in solution up to room temperature. Compound 1 reacts with C5H5Li and CO to give [MeO(CH2CH2O)3(CH2)3C5Me4]Fe(C5H5) (2) and [MeO-(CH2CH2O)3(CH2)3C5Me4]Fe(CO)2CI (3), respectively, in high yields.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951281113
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  • 85
    Digitale Medien
    Digitale Medien
    [Cp4Fe4(E2)2] Clusters with Triangulated Dodecahedral Fe4E4 Skeletons (E = P, As)Dedicated to Professor Herbert Schumann on the occasion of his 60th birthday. (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1145-1148 
    Details
    ISSN: 0009-2940
    Schlagwort(e): P2, As2, P2S2, and P2Se2 ligands ; Iron complexes ; Triangulated dodecahedra ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The thermolysis of [CpFe(CO)2]2 (1) and P4 or As4 affords the iron clusters [Cp4Fe4(E2)2], E = As (2a), P (2b), the Fe4E4 skeleton of which consists of a triangulated dodecahedron. S8 and gray Se oxidize the P2 ligands of 2b with formation of [Cp4Fe4(P2X2)2], X = S (3a), Se (3b), complexes with the hitherto unknown P2X2 ligands, 2a, b and 3a, b have been characterized by X-ray crystallography.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951281202
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  • 86
    Digitale Medien
    Digitale Medien
    Functionalized Diorganozinc Compounds: Key Reagents for the Synthesis of Enantiomerically Pure 2,5-Disubstituted cis- and trans-Tetrahydrofurans (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1021-1028 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Synthesis, stereoselective ; Catalysis ; Tetrahydrofurans ; Dialkylzinc reagents ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 1,4-Diol derivatives 4a-i were synthesized stereoselectively by either reagent- or catalyst-controlled routes using the addition of functionalized diorganozinc reagents to aldehydes. The stereoselectivities along the reagent-controlled synthetic path were in the range between 80:20 and 95:5. The stereoselectivities along the catalyst route exceeded 95:5. The 1,4-diol derivatives 4 thus obtained were transformed into enantiomerically pure cis- and trans-2,5-disubstituted tetrahydrofurans (16-20) by means of an intramolecular Williamson reaction.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951281010
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  • 87
    Digitale Medien
    Digitale Medien
    Contributions to the Chemistry of Boron, 231Part 230: Ref.. Synthesis and Structures of Borylated HydrazinesDedicated to Professor H. P. Fritz on the occasion of his 65th birthday. (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1187-1194 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Hydrazines ; N,N'-bis(diphenylboryl)-N,N'-dimethyl- ; N,N'-bis(diphenylboryl)-N',N'-dimethyl- ; N,N'-bis(dimethylphenylsilyl)- ; N,N'-bis(chloromesitylboryl)-N'-phenyl-N'-(trimethylsilyl)- ; 1,2,4,5,3,6-Tetrazadiborinane, 1,2,4,5-tetrakis(tert-butyldimethylsilyl)-3,6-difluoro- ; Triazadiborolidine, dihydro-, derivative ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The diboration of the diazene PhN = NSiMe3 (15) by diborane(4) derivatives provides a new synthetic route to N,N'-diborylated hydrazines. The product formed depends on the type of the diborane(4) compound. Thus, addition of dimesityldiboron dichloride to 15 in a 1:1 ratio afforded (mesCIB)PhN-N(SiMe3)(BClmes) (16) while bis(dimethyl-amino)diboron dichloride was found to react in a 1:2 ratio to give a triazadiborolidine derivative 17. In addition, it was demonstrated that in the solid state Me2N-N(BPh2)2 (8) is a derivative of a three-membered dihydroazadiboriridine C while its isomer, (Ph2B)MeN-NMe(BPh2) (7), forms no BN coordinative bond. The new 3,6-difluoro-1,2,4,5-tetraza-3,6-diborine 13 shows a twist conformation. The molecular structures of all these compounds were determined by X-ray crystal structure analysis, and the influence of the B substituent on the conformation is discussed.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951281209
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  • 88
    Digitale Medien
    Digitale Medien
    Metal Complexes of Functional Isocyanides, XXV. Amino(hydrazino)carbene Complexes (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1061-1068 
    Details
    ISSN: 0009-2940
    Schlagwort(e): N-Isocyanides ; N-Isocyanodialkylamine complexes ; Carbene complexes ; Imaging-Plate data collection ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The N-isocyanodialkylamine metal complexes [M(CO)5CN-NR2] (M = Cr, W), trans-[MI2(CNNR2)2] (M = Pd, Pt), trans-[Pt(Cl)(CNNR2)(PPh3)2]BF4, and cis-[PtCl2(CNNR2)(PPh3)] [R = Et, iPr; 2 R = -{CHMe(CH2)3CHMe}-] react with primary amines to give the amino(hydrazino)carbene metal complexes [M(CO)5(C(NHR′)NHNR2}] (R′ = Me, nPr, Cy) (1-9), trans-[PtI2{C(NHMe)NHNR2}2] (10-12) and trans, and the amine adducts cis-[PtCl2{C(NHMe)NHNC(H)(Me) (CH2)3CHMe}(PPh3)] H2NMe (14), and trans-[PdI2{C (NHMe)NHNC(H)(Me)(CH2)3CHMe}2] 2 H2NMe (15). With secondary amines the amino(hydrazino)carbene metal complexes trans (18) and trans-[PtCl{C(NEt2)NHNEt2} (PPh3)2]BF4 (19) Were isolated. The complexes trans-[PtI2{C(NHCy)NHNiPr2}CNNiPr 2] (20) and trans-[PdI2 (NH2Cy){C(NHCy)NHNiPr2}] (21) were obtained by reaction of trans-[MI2(CNNiPr2)2] (M = Pd, Pt) with cyclohexylamine. The structures were assigned on the basis of IR, NMR- (1H, 13C, 31P), and mass spectroscopy as well as an X-ray structural analysis of 21.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951281102
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  • 89
    Digitale Medien
    Digitale Medien
    Metallocenophanes, VIIPart VI: Ref.. Preparation and Characterisation of the Disilver(I) Complexes of Conjugated Polyenes with [2.2.2]Paracyclophanyl End Groups (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1079-1082 
    Details
    ISSN: 0009-2940
    Schlagwort(e): [2.2.2]Paracyclophanes ; Polyenes ; Silver complexes ; X-Ray structural analysis ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The preparation of the disilver(I) complexes 3 and 4, polyene metal complexes that are terminally substituted with [2.2.2]paracyclophanyl units, is described. NMR spectro-scopic studies on the disilver perchlorate complex 3b showed that (a) the sites of complexation are the cyclophane groups and (b) the olefinic spacers do not overly perturb the overall complexation properties of the individual [2.2.2]paracyclo-phanyl groups. The crystal structures of the disilver hexafluo-roantimonate complexes 4a-b were determined. The use of the hexafluoroantimonate counterion and solvent mixtures containing toluene both proved crucial in obtaining single crystals; toluene is incorportated into the crystal lattices.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951281104
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  • 90
    Digitale Medien
    Digitale Medien
    Highly Substituted Tris(pyrazolyl)methane Ligands and Some Zinc Complexes Thereof (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1095-1103 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Zinc complexes ; Tridentate ligands ; Tris(pyrazolyl)methane ; Reactivity ; Structure ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Tris(pyrazolyl)methane ligands in which two or three of the pyrazole carbon atoms bear organic substituents (L1-L7) were synthesized from chloroform and the corresponding pyrazole under phase transfer conditions. Their behavior towards zinc salts was found to span the range from no reaction at all to hydrolytic destruction. One hydrolysis product isolated and structurally characterized was the perchlorate complex [(HPz5)3Zn-OClO3]ClO4 (1), other ones were the 2:1 complexes (HPz3)2ZnBr2 (2) and (HPz6)2Zn(NO3)2 (3, HPzn = substituted pyrazole). Zinc perchlorate and tris(trimethylpy-razolyl)methane (L2) formed the octahedral binary complex [L22Zn](ClO4)2 (4) as evidenced by a structure determination. Zinc halides produced the 1:1 complexes L1 · ZnBr2 (5), L4 · ZnCl2 (6), and L4 · ZnBr2 (7), which according to the structure determinations of 6 and 7 contain tetrahedral ZnN2Hal2 units with only bidentate tris(pyrazolyl)methane ligands. In contrast, the zinc nitrate complex L4 · Zn(NO3)2 (8) was found to have an octahedral structure with mono- and bidentate nitrate and tridentate L4. The bromide complex 7 was converted by silver perchlorate hydrate into the labile compound [L4 · ZnBr]ClO4 (9) and then into the unstable product [L4 · Zn-OH2](ClO4)2 (10), both presumed to contain zinc in a tetrahedral ZnN3Br or ZnN3O environment, respectively. The ease of hydrolytic self-destruction prevented the exploitation of the reactivity of 9 and 10 in analogy to that of the corresponding tris(pyrazolyl)borate zinc complexes.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951281107
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  • 91
    Digitale Medien
    Digitale Medien
    Unusual Complexation Behavior of Metallomacrocycles Based on Isothiosemicarbazides with Respect to Alkali and Alkaline Earth Metal Ions: Novel 2:1 Associates (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1089-1093 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Metallomacrocycles ; Nickel complexes ; Complexation reactions ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reactions between alkali and alkaline earth metal ions and nickel(II) macrocycles based on S-alkylated isothiosemi-carbazides with different crown ether cavity size were studied in propylene carbonate by spectrophotometric and calorimetric titrations. Metallomacrocycles 1 and 2 exhibit normal behavior on 1:1 complexation with alkali- and alkaline earth metal ions and resemble in this respect 15C5 and 18C6, respectively. The most stable complexes are formed by these “ligands” when the diameter of the cation and the crown ether hole have approximately the same size. The most striking feature of the complexation processes studied is the formation of 1:2 metal-ligand associates even in the case of the smallest cations. These associates are very different from “normal” crown ether sandwich complexes. In reality, the particle formed is an associate between a 1:1 complex, in which the corresponding metal ion is well accommdated inside the ligand cavity, and a second metallomacrocyclic ligand. Their formation is disfavored by enthalpic contributions. A special kind of “switch” from these associates to normal sandwich complexes takes place in the case of 1, when the cation diameter compared to hole size increases. The macrocycle 2 forms this kind of associates with all akali and alkaline earth ions.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951281106
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  • 92
    Digitale Medien
    Digitale Medien
    Synthesis and Reactivity of Silicon Transition Metal Complexes, 3433. Mitteilung: Lit.. Pentachlordisilanyl- und Disilanyl-Komplexe von Molybdän und Wolfram: Darstellung, Struktur und spektroskopische CharakterisierungHerrn Professor Hubert Schmidbaur zum 60. Geburtstag gewidmet. (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1109-1115 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Silicon transition metal complexes ; Metallodisilanes ; Nucleophilic metallation ; Cl/H exchange at silicon ; Raman spectroscopy ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Synthesis and Reactivity of Silicon Transition Metal Complexes, 34[*].  -  Pentachlorodisilanyl and Disilanyl Complexes of Molybdenum and Tungsten: Synthesis, Structure, and Spectroscopic CharacterizationReaction of the lithium metallates Li[M(PMe3)(CO)2C5R5] [M = Mo, W; R = H (1a, b), Me (1c, d)] with Si2Cl6 (2) leads to the formation of the pentachloro(metallo)disilanes 5R5(OC)2(Me3P)M - SiCl2 - SiCl3 (3a - d), which are transformed into the metallo disilanes C5R5(OC)2(Me3P)M - SiH2 - SiH3 (4a - d) on treatment with LiAlH4. The disilanes 4a - d are reconverted into 3a - d in the presence of tetrachloromethane. Extensive spectroscopic investigations (NMR, Raman, and IR spectroscopy) were performed to establish the transition-metal effect especially with respect to the H5Si2 ligand. The molecular structure of C5Me5(OC)2(Me3P)W - SiCl2 - SiCl3 (3d) was determined by single-crystal X-ray diffraction.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951281109
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  • 93
    Digitale Medien
    Digitale Medien
    Octacarbonylbis {μ-(tris(trimethylsilyl)methyl]indany l} dimanganese with Two Monoalkyl Indium Groups Bridging the Mn-Mn Bond (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1137-1139 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Tetraindane(4) ; Indium(I) ; Mn-Mn bond ; Indium alkyl bridge ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Tetrahedra-tetrakis[tris(trimethylsilyl)methyl]tetraindane(4) (1) reacts with decacarbonyldimanganese(0) to yield the bright red crystalline title compound 2, in which two carbonyl ligands are replaced by two InR fragments. The crystal structure determination of 2 shows two Mn(CO)4 groups (Mn-Mn 313.7 pm) bridged by two monoalkylindium units and a planar Mn2In2 molecular center.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951281114
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  • 94
    Digitale Medien
    Digitale Medien
    Thioselonocarboxylic Ester, Selenetane, and Dihydrodiselenine Complexes Prepared from Pentacarbonyl(selenobenzaldehyde)tungsten with π-Donor-Substituted Alkynes (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1149-1156 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Selenoaldehyde complex ; Thioselonocarboxylic ester complexes ; Selenetane complex ; Dihydrodiselenine complex ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Pentacarbonyltungsten-coordinated selenobenzaldehyde, [(CO)5W{Se=C(Ph)H}] (1), reacts with tBu-C≡C-SMe (2) by insertion of the C≡C into the Se=C bond to form in a highly regio- and stereoselective manner the α,β-unsaturated thioselonocarboxylic ester complex (Z)(C=C)-[(CO)5W{≡1-Se=C(SMe)C(tBu)=C(Ph)H}] (3). The thioselonocarboxylic ester ligand is cleaved intact from the metal by treatment of 3 with [NEt4]Br. Three complexes are formed in the reaction of 1 with Me-C≡C-SMe (5): the thioselonocarboxylic ester complex [(CO)5W{≡1-Se=C(SMe)C(Me)=C(Ph)H}] (6) as a mixture of the (E) and (Z)(C=C) isomers, a selenetane complex (7) and a dihydrodiselenine complex (8). The product distribution depends on the ratio 1:5 and on the solvent. The reaction of 1 with the bis(organylthio)alkynes RS-C≡C-SR (9) [R = Me (a), iPr (b), 2,6-C6H3Me2 (c)] yields mixtures of the (E) and (Z)(C=C) isomers of the α,β-unsaturated α-organylthio thioselonocarboxylic ester complexes [(CO)5W{≡1-Se=C(SR)C(SR)=C(Ph)H)] (10a-c). In contrast, the reaction of 1 with tert-butoxyethyne, H-C≡C-OtBu (11), affords a bis(pentacarbonyltungsten) 5,6-dihydro-1,2-diselenine complex (12). Compound 12 is probably formed by consecutive reaction of 1 with 11 to give the selonocarboxylic ester complex [(CO)5W{≡1-Se=C(OtBu)C(H)=C(Ph)H}] which then further reacts as a heterodiene by highly regioselective [4 + 2] cycloaddition with the Se=C bond of a second molecule of 1 to give 12. In the reaction of 1 with 5 and 9a the isomer with a trans arrangement of C(=Se)SMe and Ph is the kinetically controlled reaction product [(E)-6 and (Z)-10a, respectively]. The formation of (E)-6 and (Z)-10a is followed by isomerization until an (E)/(Z) equilibrium is reached. Complexes 3 and 7 were characterized by X-ray structural analyses.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951281203
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  • 95
    Digitale Medien
    Digitale Medien
    Tin for Organic Synthesis, 13Part 12: Ref.. A New and Regioselective Method for the Synthesis of Aromatic, Heteroaromatic, and Olefinic Sulfonamides by Electrophilic Destannylation (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1195-1198 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Electrophilic aromatic substitution ; Electrophilic vinylic substitution ; Trialkylstannanes, application of ; Sulfonamides, synthesis of ; Sulfodestannylation, application of ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A mild and effective method for the preparation of aromatic and olefinic sulfonamides is described. The reaction of trialkylaryl- (4a-f), heteroaryl- (4g), and vinylic stannanes (4h) with sulfuryl chloride and secondary amines provides the corresponding sulfonamides in an ipso-specific manner.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951281210
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  • 96
    Digitale Medien
    Digitale Medien
    Ylidylphosphorsulfide, -selenide, -disulfide, -sulfidselenide und -diselenide (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1207-1219 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Ylide-substituted phosphorus ; Phosphorus sulfides ; Phosphorus selenides ; Thioxophosphanes ; Selenoxo-phosphanes ; Dithioxophosphoranes ; Diselenoxophosphoranes ; Alkylation reactions ; Selenadiphosphirane ; 2,5,7-Triselena-1,3,4,6-tetraphosphanorbornane ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Ylidylphosphorus Sulfides, Selenides, Disulfides, Sulfide Selenides, and DiselenidesWe report on the first stable monomeric phosphorus mono-chalcogenides 2, 8 and the first stable dichalcogenides 4, 10 without bulky or intramolecularly coordinating substituents. They are stabilized by a high contribution of the zwitterionic resonance formula, which follows both from the NMR spectra and from an X-ray structure determination. Their preparation starts from triphenylphosphoniumylidyl-dichlorophosphanes 1. For the monochalcogenides they are treated with sodium sulfide or selenide or better with bis(trimethylsilyl) sulfide or selenide. In case of the C-phenyl and C-meta-tolyl representatives and also of the C-trimethylsilyl compound a number of secondary, partly novel products are obtained. - The dichalcogenides result from the reaction with sodium disulfide and diselenide, respectively, or from the oxidation of the monochalcogenides. - Alkylation of the monochalcogenides results in ylidylalkylchalcogenophosphenium salts 13, 15. In solution they are in equilibrium with more or less of the covalent form 14, 16, depending on the anion and on the solvent. Alkylation is often accompanied by secondary reactions. A diselenide loses selenium on alkylation.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951281212
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  • 97
    Digitale Medien
    Digitale Medien
    Synthesis and Reactivity of Silicon Transition Metal Complexes, 3332. Mitteilung: Lit.. Metallo Silanols and Metallo Siloxanes, 87. Mitteilung: Lit.. Metallo-silanole vom Typ C5R5(OC)2(Me3P)M - SiPh2OH (M = Cr, Mo, W): Darstellung nach der Dimethyldioxiran-Methode und Überführung in funktionalisierte Metallo-disiloxaneHerrn Professor Max Schmidt zum 70. Geburtstag gewidmet. (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1251-1255 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Oxofunctionalization ; Dimethyldioxirane ; Metallo silanes ; Metallo silanols ; Metallo siloxanes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Synthesis and Reactivity of Silicon Transition Metal Complexes, 3332. Mitteilung: Lit. .  -  Metallo Silanols and Metallo Siloxanes, 8 7. Mitteilung: Lit. .  -  Metallo Silanols of the Type C5R5(OC)2(Me3P)M-SiPh2OH (M = Cr, Mo, W): Preparation According to the Dimethyldioxirane Route and Conversion into Metallo Disiloxanes Herrn Professor Max Schmidt zum 70. Geburtstag gewidmet.The metallo silanes C5R5(OC)2(Me3P)M-SiPh2H (4a-c), are converted into the corresponding metallo silanols C5R5(OC)2-(Me3P)M-SiPh2OH [R = H, M = Cr (6a); R = Me, M = Mo (6b); M = W (6c)] by oxofunctionalization with dimethyldioxirane (5). Treatment of 6b, c with the chlorosilanes Me2Si(R)Cl [R = H (3b), [R = Cl (3c)] in the presence of triethylamine gives access to the metallo disiloxanes C5Me5(OC)2(Me3P)M-SiPh2OSiMe2R (M = Mo, R = H (7a); M = W, R = Cl (7b)]. The structure of tungsten silanol 6c is determined by X-ray diffraction analysis.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951281217
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  • 98
    Digitale Medien
    Digitale Medien
    Synthesis and Characterization of β-Phosphaenones An Investigation on the Conjugative Properties of the P=C Bond (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 465-476 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Phosphaalkenes, C-halo, C-metal ; Phosphaacrylic acid ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Thermally and air-stable β-phosphaenones were synthesized by functionalization of Mes*P=CCl2 (1; Mes* = supermesityl = 2,4,6-tri-tert-butylphenyl). At low temperature, 1 was lithiated by halogen-metal exchange with n-butyllithium to give the phosphanylidene carbenoid (Z)-Mes*P=C(Cl)Li [(Z)-2] which reacted with acid chlorides to furnish the C-carbonyl-substituted phosphaalkenes (Z)-Mes*P=C(Cl)R (3: P = COtBu; 4: R = COPh; 5: R = COOEt). The reaction of (Z)-2 with carbon dioxide furnished the carboxylate 6, which was converted by treatment with pivaloyl chloride or trimethylsilyl chloride into the phosphaalkenes 7 and 8 functionalized at the carbon atom by an anhydride or a trimethylsilyl ester function, respectively. Acidification of 6 or hydrolysis of 8 with water in chloroform solution afforded the novel carboxylic acid (Z)-Mes*P=C(Cl)COOH (9). Spectroscopic investigations (NMR, UV, IR) of 3-9 and the X-ray structures of 3 and 4 are presented. Based on these properties and on theoretical calculations, the occurrence of conjugation in the β-phosphaenone system is discussed and compared with the well-known conjugation in normal enones.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280506
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  • 99
    Digitale Medien
    Digitale Medien
    Reactions of Phosphaalkenes with HexafluoroacetoneDedicated to Professor H. M. R. Hoffmann on the occasion of his 60th birthday. (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 499-502 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Phosphaalkenes ; Cycloadditions ; Insertion reactions ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The dimethylamino-substituted phosphaalkene 1 reacts with hexafluoroacetone (HFA) with addition at the P=C bond to form the 1,5,2-dioxaphosphorinane 2. The structure of 2 was confirmed by an X-ray crystal structure analysis. The six-membered ring displays an envelope conformation with the phosphorus atom out of the plane, but the phosphorus is disordered over two sites. Reaction of P-trimethylsilyl-substituted phosphaalkenes with HFA proceeds with retention of the P=C double bond and insertion of HFA into the P—Si bond. Two isomeric products are obtained and are characterized by 1H-, 13C-, 19F-, and 31P-NMR spectroscopy, IR spectroscopy, mass spectrometry, and elemental analysis.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280511
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  • 100
    Digitale Medien
    Digitale Medien
    Monomere (Acetylacetonato)kupfer(I)-Komplexe von Alkinen und 1,4-Diinen (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 525-529 
    Details
    ISSN: 0009-2940
    Schlagwort(e): Copper complexes ; Acetylacetonate ; Alkynes ; 1,4-Diynes ; Titanocenes ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Monomeric (Acetylacetonato)copper(I) Complexes of Alkynes and 1,4-DiynesMonomeric (η2-Me3SiC≡CSiMe3)Cu(acac) (3) is formed by the reaction of dimeric [(η2-Me3SiC≡CSiMe3)CuBr]2 (1) with two equivalents of Na(acac) (2). In a similar manner Me2-Si(C≡CSiMe3)2 (4) reacts with CuCl (5) and 2 to afford Me2Si[(η2-C≡CSiMe3)Cu(acac)]2 (6). In compounds 3 and 6 an alkyne unit is η2-coordinated to a monomeric Cu(acac) moiety with a copper atom in a planar environment. With the organometallic 1,4-diyne (η5-C5H4SiMe3)2Ti(C≡CSiMe3)2 (7), compound [(η5-C5H4SiMe3)2Ti(C≡CSiMe3)2]Cu(acac) (8) is formed. In 8 both Me3SiC≡C ligands of the 3-titanapenta-1,4-diyne fragment are η2-coordinated to a monomeric Cu-(acac) building block. The copper atom in 8 possesses a pseudo-tetrahedral environment (shown by X-ray analysis), built by the two Me3SiC≡C ligands of the (η5-C5H4SiMe3)2-Ti(C≡CSiMe3)2 moiety and the two oxygen atoms of the acetylacetonato ligand. 8 is additionally formed by the reaction of 3 or 6 with 7, or by treatment of [(η5-C5H4SiMe3)2Ti(C≡C-SiMe3)2]CuCl (9) with Na(acac) (2). The application of 3, 6, and 8 as precursors for the preparation of copper films in the CVD process of copper(I) is discussed.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/cber.19951280515
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