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  • Articles: DFG German National Licenses  (1,543)
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  • Articles: DFG German National Licenses  (1,543)
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  • 1995-1999  (652)
  • 1975-1979  (891)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Lasers in medical science 10 (1995), S. 93-104 
    ISSN: 1435-604X
    Keywords: Copper vapour laser ; Electron microscopy ; Illumination time ; Numerical modelling ; Optimal treatment ; Port-wine stain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics , Technology
    Notes: Abstract This paper reports the electron microscopy results obtained from two patients who were treated with 5 W of yellow (578 nm) light from a copper vapour laser with an illumination time of 3.6 ms and a 0.3 mm spot diameter. The endpoint of treatment was transient blanching. Following treatment, erythema was observed. There was minimal damage to the epidermis and non-vascular tissue such as the nerve fibres. There was severe damage to the endothelial cells of the ectatic vessels. Twenty-four hours after treatment, platelet activation and collagen were present, indicating that these vessels were no longer viable. Theoretical calculations are used to determine the flow of heat within and away from a 50μm diameter vessel. From this, heating of the entire vessel is shown to occur with illumination times of 4 ms, with minimal heating of the non-vascular tissue. Shorter illuminations do not heat the entire vessel, while the use of longer illumination times will cause excessive damage to the surrounding non-vascular tissue. Illumination times close to 4 ms must be regarded as optimal.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 73 (1995), S. 73-77 
    ISSN: 1432-1440
    Keywords: Chloroquine ; Cardiomyopathy ; Heart ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Light microscopic and ultrastructural findings in patients suffering from chloroquine-induced cardiomyopathy are reviewed. Based on our own observations in an autopsy case, functional and morphological similarities between chloroquine effects and hereditary lysosomal storage diseases are discussed.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-2307
    Keywords: Graft-versus-host disease ; Cell blebs ; Light microscopy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Subnuclear blebbing of the superficial colonic epithelium, a rarely described light and electron microscopic change in graft-versus-host disease (GVHD), was studied in a murine model of GVHD. Severity of changes induced by transfer of various donor T cell subsets to irradiated, allogeneic recipients, and association with more severe alterations such as erosions and ulceration were evaluated. By light microscopy the basal region of the superficial enterocytes was greatly expanded by eosinophilic to amphophilic, flocculent, sometimes vacuolated material. By electron microscopy these changes were found to be organelle-poor, cytoplasm-filled protrusions from the basal surface of the epithelium. In this model, helper T cells (CD4+-enriched, CD8+-depleted T cells) transplanted after high dose irradiation were capable of causing the change suggesting cytokine responses may be involved in mediating the cellular injury seen histologically. Close association of blebbing and erosions suggest the blebbing may be the precursor to epithelial erosion or denudation seen in severe intestinal GVHD.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-2307
    Keywords: Giant cell tumour of bone ; In vitro resorption ; Leukaemia inhibitory factor ; Synthetic calcium phosphate ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Osteoclastic cells from giant cell tumour of bone (GCT) of bone provide a rich source for investigation of cellular mechanisms leading to formation of multinucleated cells, the resorption process and involvement of hormones and cytokines in these events. In the present study we investigated the effect of 1,25-dihydroxyvitamin D3 (VD3) and leukaemia inhibitory factor (LIF) on the resorbing potential of osteoclast of GCT origin using quantitative image-analysis of resorption lacunae in an in vitro dentine model. While VD3 unsignificantly increased the number of resorption pits and implicated surface after 7 days of GCT cell culturing, the stimulative effect of LIF was statistically significant. In cultures supplemented with LIF (5000 U/ml) the number of lacunae and resorption surface increased by 38% and 55%, respectively, when compared with control cultures. We suggest that both osteotropic agents increased osteoclastic activity, as the number of multinucleated cells was similar in control and experimental cultures. Seeding of GCT cells on biphasic calcium phosphate substratum revealed the relative inability of osteoclastic cells to resorb this synthetic material.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 426 (1995), S. 523-528 
    ISSN: 1432-2307
    Keywords: Von Hippel-Lindau disease ; Neuroendocrine tumour ; Electron microscopy ; Flow cytometry ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A 21-year-old woman with a family history of von Hippel-Lindau disease presented with a mass in the head of the pancreas. Light microscopic features of the tumour suggested neuroendocrine differentiation and although it displayed positive immunostaining for the antigens expected in a neuroendocrine neoplasm, S-100 staining was also present. This unusual feature prompted further evaluation by routine and post-embedding protein-A gold immunoelectron microscopy, which demonstrated the presence of neuroendocrine granules. Tumour cell DNA content was normal by flow cytometry. Although this patient exhibited no other signs of von Hippel-Lindau disease, the presence of a pancreatic tumour with neuroendocrine differentiation demonstrated that she was affected. Future surveillance and genetic counselling will be influenced by this diagnosis.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1572-9648
    Keywords: Electron microscopy ; Microstructures ; Phase transitions ; Solid mechanics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Sommario Si presentano i risultati di alcuni studi fatti attraverso la microscopia elettronica sulle microstrutture relative a transizioni di fase in una varietà di materiali. I casi comprendono leghe binarie e ternarie, superconduttori TC e materiali C60 e C70; le transizioni esaminate sono diffusionali, displacive o di entrambi i tipi.
    Notes: Abstract In this contribution the results of some electron microscopy studies on microstructures related with phase transitions in a variety of materials will be presented. The materials include binary and ternary alloys, high TC superconductors as well as C60 and C70 fullerenes, while the transitions can be diffusional, displacive or both.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-0533
    Keywords: Key words Tonsillar herniation ; Syringomyelia ; Chiari malformations ; Histology ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This report describes an experimental model of chronic tonsillar herniation and its effects on the spinal cord. In ten rats, a small piece of chemically induced mammary cancer was transplanted to the supraoccipital bone. In all cases, the transplanted cancers grew into the posterior fossa, destroying the supraoccipital bone and compressing the cerebellum extradurally. In six of the ten rats, tonsillar herniation was observed at 8–14 weeks after transplantation. Transdural infiltration of the tumor cells was not apparent in any animal. In those rats with tonsillar herniation (n = 6), the spinal cord from the C5 to the T8 segments showed enlargement of the central canal without exception. Histological examination revealed the following changes: stretching and thinning of the ependymal cells; swelling of the astrocytic processes; and extracellular edema, predominantly in the dorsal gray matter, but also in the ventral inner portion of the dorsal column. In the control group (n = 4) and those rats without tonsillar herniation (n = 4), such histological changes of the spinal cord were not observed. Although the lesions can not be regarded as representing mature syringomyelia, they most likely constitute an earlier evolutionary stage.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 192 (1995), S. 265-274 
    ISSN: 1432-0568
    Keywords: Lymphatics ; Valves ; Microanatomy ; Vimentin filaments ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The microanatomy and ultrastructure of the feline and canine thoracic duct and afferent lymphatics were studied by scanning and transmission electron microscopy. We found that the lymphatic vessels were always terminated by ostial valves of two shapes, crescent- and navicular-like, in a ratio of 4∶1. Specific regulatory structures along the free edges of the valves, including marginal thickenings and buttresses, are described. The tissue and cellular organization of the valve endothelium showed distinct peculiarities, particularly in the orientation and shape of the cells and their microrelief. We found that valvular endothelial cells, especially „tip cells”, which are situated in unfavourable lymphodynamic conditions, were characterized by an increased volume density of intermediate (probably vimentin-based) filaments, suggesting an accommodative mechanism involving such filaments.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-0533
    Keywords: Tonsillar herniation ; Syringomyelia ; Chiari malformations ; Histology ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This report describes an experimental model of chronic tonsillar herniation and its effects on the spinal cord. In ten rats, a small piece of chemically induced mammary cancer was transplanted to the supraoccipital bone. In all cases, the transplanted cancers grew into the posterior fossa, destroying the supraoccipital bone and compressing the cerebellum extradurally. In six of the ten rats, tonsillar herniation was observed at 8–14 weeks after transplantation. Transdural infiltration of the tumor cells was not apparent in any animal. In those rats with tonsillar herniation (n=6), the spinal cord from the C5 to the T8 segments showed enlargement of the central canal without exception. Histological examination revealed the following changes: stretching and thinning of the ependymal cells; swelling of the astrocytic processes; and extracellular edema, predominantly in the dorsal gray matter, but also in the ventral inner portion of the dorsal column. In the control group (n=4) and those rats without tonsillar herniation (n=4), such histological changes of the spinal cord were not observed. Although the lesions can not be regarded as representing mature syringomyelia, they most likely constitute an earlier evolutionary stage.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 90 (1995), S. 194-197 
    ISSN: 1432-0533
    Keywords: Key words Alzheimer's disease ; Paired helical ; filaments ; Electron microscopy ; Tau
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To investigate if Alzheimer paired helical filaments (PHF) closely resemble twisted ribbons, as indicated by recent high-resolution ultrastructural studies, we compared physical models of twisted ribbons with electron microscopic images of PHF. Uranyl-acetate-stained, isolated PHF with one or two helical turns were compared with scale models of twisted ribbons with one and two helical turns rotated at different angles. The various rotations of the twisted ribbon model corresponded well with the different orientations of randomly dispersed PHF. The electron-dense regions of individual PHF turns previously thought to represent a cross-over site of paired filaments corresponded to the edge of the twisted ribbon when the ribbon was oriented perpendicular to the filament axis. These data indicate that the overall configuration of PHF is a twisted ribbon but does not exclude possible configuration restrictions due to an ordered arrangement of subunits.
    Type of Medium: Electronic Resource
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 90 (1995), S. 194-197 
    ISSN: 1432-0533
    Keywords: Alzheimer's disease ; Paired helical filaments ; Electron microscopy ; Tau
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To investigate if Alzheimer paired helical filaments (PHF) closely resemble twisted ribbons, as indicated by recent high-resolution ultrastructural studies, we compared physical models of twisted ribbons with electron microscopic images of PHF. Uranyl-acetate-stained, isolated PHF with one or two helical turns were compared with scale models of twisted ribbons with one and two helical turns rotated at different angles. The various rotations of the twisted ribbon model corresponded well with the different orientations of randomly dispersed PHF. The electron-dense regions of individual PHF turns previously thought to represent a cross-over site of paired filaments corresponded to the edge of the twisted ribbon when the ribbon was oriented perpendicular to the filament axis. These data indicate that the overall configuration of PHF is a twisted ribbon but does not exclude possible configuration restrictions due to an ordered arrangement of subunits.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 89 (1995), S. 85-95 
    ISSN: 1432-0533
    Keywords: Neonatal de-efferentation ; Sensory denervation ; Electron microscopy ; Intrafusal muscle fibre types ; Postnatal myogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The ultrastructure of muscle spindles de-efferented by the extirpation of the lumbosacral spinal cord at the age of 2 days and subsequently deprived of their sensory innervation by the section of the sciatic nerve at 3–4 weeks of age was studied in serial sections of 2-month-old rat hindlimb muscles. De-efferentation leaves the primary sensory neurons and their peripheral axons intact and capable of inducing the muscle spindle morphogenesis during the critical period of their development. In de-efferented and subsequently denervated muscle spindles, new supernumerary intrafusal muscle profiles (SIPs) appeared in the muscle spindle A region. They were formed in intimate spatial relation with the original intrafusal muscle fibres (IMFs) predominantly from activated satellite cells derived from both nuclear bag (larger diameter) and nuclear chain fibres. SIPs, however, lacked the typical nuclear accumulations, as well as other ultrastructural distinctions present in control IMFs. The majority of differentiated SIPs separated from original IMFs, whereas the less differentiated SIPs were usually closely apposed to the surface of the parent IMFs and both were covered by the common basal lamina. In some spindles, the original IMFs and/or new SIPs at different stages of their differentiation were found together and they formed clusters of variable shape and composition. In the majority of clusters, all profiles seemed to be isolated along their entire length, although in few clusters, occasional cytoplasmic connections of variable length between intrafusal profiles were found. This result is important for the interpretation of the forthcoming study of expression of muscle spindle-specific myosin heavy chain isoforms in denervated SIPs in rat muscle spindles gradually deprived of their motor and sensory innervation.
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  • 13
    ISSN: 1432-0533
    Keywords: Astrocytes ; Alzheimer's disease ; Electron microscopy ; Paired helical filaments ; Straight tubules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Ultrastructural investigation of the hippocampal CA1 and CA4 of nine sutopsy-proven cases of dementia of the Alzheimer type (duration of disease: 3–16 years; age: 76–92 years) revealed paired helical filaments (PHFs) and straight tubules (STs) in astrocytes of three advanced cases of long duration (〉13years). The PHFs and STs were indistinguishable from those seen in neurons. The abnormal glial fibrils were confined to the astrocytic processes that were associated with small vessels or, more frequently, with ghost tangles. In both locations the astrocytic PHFs and STs were located in the cytoplasm without limiting membranes, and were thicker than the straight filaments that composed ghost tangles. These findings, combined with the presence of regular constrictions of astrocytic PHFs, suggest that abnormal astrocytic fibers are produced by the glial cells, not engulfed by them. In addition, the presence of these abnormal glial filaments in only advanced, long-duration cases of dementia of the Alzheimer type suggests that disease duration has a significant effect upon the formation of these astrocytic profiles.
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  • 14
    ISSN: 1432-0533
    Keywords: Key words Astrocytes ; Alzheimer's disease ; Electron microscopy ; Paired helical filaments ; Straight tubules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Ultrastructural investigation of the hippocampal CA1 and CA4 of nine autopsy-proven cases of dementia of the Alzheimer type (duration of disease: 3–16 years; age: 76–92 years) revealed paired helical filaments (PHFs) and straight tubules (STs) in astrocytes of three advanced cases of long duration (〉13 years). The PHFs and STs were indistinguishable from those seen in neurons. The abnormal glial fibrils were confined to the astrocytic processes that were associated with small vessels or, more frequently, with ghost tangles. In both locations the astrocytic PHFs and STs were located in the cytoplasm without limiting membranes, and were thicker than the straight filaments that composed ghost tangles. These findings, combined with the presence of regular constrictions of astrocytic PHFs, suggest that abnormal astrocytic fibers are produced by the glial cells, not engulfed by them. In addition, the presence of these abnormal glial filaments in only advanced, long-duration cases of dementia of the Alzheimer type suggests that disease duration has a significant effect upon the formation of these astrocytic profiles.
    Type of Medium: Electronic Resource
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 192 (1995), S. 257-264 
    ISSN: 1432-0568
    Keywords: Cholinesterases ; Electron microscopy ; Development ; Mouse embryo ; Somites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract During the development of somites in mouse embryos, widespread activity of unspecific cholinesterase (BuChE) was demonstrated after prolonged incubation. Independent of their position, all somite cells and their derivatives (dermatome, myotome and sclerotome) exhibited enzyme activity in the perinuclear space and in the endoplasmic reticulum. The plasmalemma did not show any enzyme activity. Differentiation of the sclerotome into vertebrae was accompanied by a reduction of BuChE. However, a low enzyme reaction was still present in the first typical differentiated chondroblasts. Notochordal cells were detectable by their high BuChE content. This was also found in cells already showed severe degeneration. In addition to BuChE, acetylcholinesterase (AChE) was first visible on day 9 of embryonic development in newly formed myotubes of the myotomes. Some hypotheses on the functional significance of embryonic BuChE are discussed in the light of these results.
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  • 16
    ISSN: 1432-0827
    Keywords: Bone sialoprotein ; osteoblast ; Bone matrix ; Electron microscopy ; Immunolocalization ; noncollagenous protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Bone sialoprotein was immunolocalized at the EM level in thin Lowicryl K4M sections of rat bone. Because of the unconventional EM morphology of the bone matrix seen in thin demineralized acrylate sections, the pattern of immunolabeling was compared with detailed structural images of demineralized bone obtained using an en bloc treatment of tissue samples with the cationic electron ‘dye’, Malachite Green (MG), which provides stabilization and retention of anionic material throughout specimen processing. A system of structures corresponding to the sites of bone sialoprotein (BSP) immunoreactivity, as seen in Lowicryl K4M thin sections, could be readily identified in the MG-treated, expoxy thin sections. This system includes the cement lines, and aggregates of similar material within mineralized bone and mineralizing osteoid. The virtual identity of BSP distribution with the arrangement of the MG-visualized material indicates that a BSP-enriched, noncollagenous phase can be demonstrated using different, unrelated tissue preparation and imaging protocols for EM. Besides improving our understanding of the distribution of bone sialoprotein in bone, these data assign a previously unrecognized structural dimension to noncollagenous material in the bone matrix.
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  • 17
    ISSN: 1432-0827
    Keywords: Cathepsin inhibitors ; Osteoclasts ; Resorption ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract This study was designed to evaluate the effects of specific and potent cathepsin inhibitors on osteoclastic resorptive functions in vitro by means of a novel ultrastructural assay system. Mouse bone marrow cell-derived osteoclasts were suspended on dentine slices and cultured for 48 hours in the presence of either E-64 (a generalized cysteine proteinase inhibitor) or Z-Phe-Phe-CHN2 (a selective cathepsin L inhibitor). After the removal of cultured osteoclasts, co-cultured dentine slices were examined using electron microscopy: backscattered (BSEM), scanning (SEM), and atomic force (AFM). In morphometric analyses of BSEM images, there were no significant differences in the areas of demineralized dentine surfaces between control and inhibitor-treated groups, suggesting that cathepsin inhibitors had no effect on dentine demineralization by cultured osteoclasts. However, in SEM and AFM observations, both inhibitors remarkably reduced to the same extent, the formation of deep resorption lacunae on dentine slices that had resulted from degradation of matrix collagen. In addition, Z-Phe-Phe-CHN2 treatment produced deeper, ring-like grooves with little collagen exposure in shallow resorption lacunae. These results strongly suggest that (1) cathepsins released by osteoclasts are involved in the formation of deep resorption lacunae, and (2) cathepsin L plays a key role in bone resorption.
    Type of Medium: Electronic Resource
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  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Intensive care medicine 21 (1995), S. 482-489 
    ISSN: 1432-1238
    Keywords: Mucociliary clearance ; Ultrastructural ciliary alterations ; Cilia ; Electron microscopy ; Intubation ; Mechanical ventilation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objective The objective of this study was to investigate whether reduced bronchial mucus transport velocity (BTV) is associated with a loss of cilia or ultrastructural abnormalities of cilia in intubated patients. Design The patients were studied prospectively in a convenience sample trial. Setting The study took place in a university hospital. Patients and participants 29 orally intubated patients in a surgical ICU. Interventions BTV was measured with radiolabeled microspheres in the right and left primary bronchus. Following these measurements, biopsy samples were taken from the bronchi for scanning (SEM) and transmission (TEM) electron-microscopic investigations. Measurements and results SEM: Patients with normal or slight impaired BTV (group 1,n=14: BTV: 8.5 mm/min (3.8–11.5); median with range) showed more cilia on the luminal surface than patients with markedly depressed BTV (p〈0.05) (group 2,n=15: BTV: 0(0–2.1)). The difference was statistically significant. The BTV values correlated moderately with the number of cilia on the luminal surface (r=0.46;p=0.02). TEM: In group 1, 6.5% (3.9–14.9) of cilia were abnormal (median with range) vs 9.3% (4.9–13.7) in group 2; these differences were not statistically significant. Neither was there any significant correlation between BTV and the frequency of abnormal cilia. Conclusions Impaired mucociliary transport in intubated patients is associated with a loss of cilia rather than ultrastructural abnormalities of cilia, which are less relevant.
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  • 19
    ISSN: 1432-1173
    Keywords: Schlüsselwörter Angiokeratoma corporis diffusum ; Lysosomale Stoffwechselstörung ; Elektronenmikroskopie ; Kapillarmikroskopie ; Key words Angiokeratoma corporis diffusum ; Lysosomal disorder ; Electron microscopy ; Capillary microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary In a 22-year-old woman with mental impairment and some signs of dysmorphism, numerous angiokeratomas developed, starting when she was 3 years old and resulting in the clinical picture of angiokeratoma corporis diffusum. Extensive laboratory analyses did not disclose any associated metabolic disorder, and electron microscopy failed to demonstrate lysosomal inclusions. Therefore, this patient can be classified as one of the rare cases of angiokeratoma corporis diffusum without associated metabolic disease (idiopathic angiokeratoma corporis diffusum).
    Notes: Zusammenfassung Bei einer 22jährigen Patientin mit ausgedehnten, ab dem 3. Lebensjahr auftretenden Angiokeratomen im Sinne eines Angiokeratoma corporis diffusum, welche zusätzlich eine Intelligenzminderung und Dysmorphiezeichen aufwies, konnte trotz intensiver Suche laborchemisch keine assoziierte Stoffwechselstörung gefunden werden. Der fehlende Nachweis einer lysosomalen Speicherung in der Elektronenmikroskopie stützte diesen Befund. Somit liegt bei dieser Patientin die seltene Situation eines Angiokeratoma corporis diffusum ohne assoziierte Stoffwechselkrankheit (idiopathisches Angiokeratoma corporis diffusum) vor.
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  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Der Pathologe 16 (1995), S. 404-407 
    ISSN: 1432-1963
    Keywords: Schlüsselwörter Nerval-neuroendokriner Komplex ; Zollinger-Ellison-Syndrom ; Magenschleimhaut ; Elektronenmikroskopie ; Key words Nerve fibre-neuroendocrine cell complex ; Stomach ; Zollinger-Ellison-Syndrom ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Nerve fibre-neuroendocrine cell complexes (NF-NEC-C's) are neuroendocrine cells located in the lamina propria of the gastrointestinal tract directly connected with nerve fibres of Meissner's plexus. We report on a patient with sporadic Zollinger-Ellison syndrome (ZES) with electron microscopically demonstrated multiple NF-NEC-C's in non-antral gastric mucosa. It is suspected that in ZES the hypergastrinaemia may represent a trophic stimulus for the proliferation of NF-NEC-C's in the gastric mucosa.
    Notes: Zusammenfassung Unter nerval-neuroendokrinen Komplexen (N-NE-K) versteht man in der Lamina propria mucosae des Magen-Darm-Traktes gelegene Nester neuroendokriner Zellen, die in direktem Kontakt zu Nervenfasern des Meissner-Plexus stehen. Es wird über einen Patienten mit sporadischem Zollinger-Ellison-Syndrom (ZES) berichtet, bei dem sich elektronenmikroskopisch in nonantraler Magenschleimhaut multiple N-NE-K fanden. Möglicherweise stellt die Hypergastrinämie bei ZES einen trophischen Stimulus für die Proliferation von N-NE-K in der Magenschleimhaut dar.
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  • 21
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 163 (1995), S. 300-306 
    ISSN: 1432-072X
    Keywords: Nitrosomonas europea ; Hydroxylamine oxidoreductase (HAO) ; Electron microscopy ; Electron spectroscopic imaging ; Quaternary structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The hydroxylamine oxidoreductase from Nitrosomonas europaea was prepared to apparent electrophoretic homogeneity. Electron microscopy of negatively stained preparations of the sample revealed an overall diameter of about 8.8 nm of the enzyme particle. The native structure was determined as a tetrahedron-like assembly of identical subunits exhibiting four protein masses.
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  • 22
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 163 (1995), S. 300-306 
    ISSN: 1432-072X
    Keywords: Key wordsNitrosomonas europea ; Hydroxylamine ; oxidoreductase (HAO) ; Electron microscopy ; Electron ; spectroscopic imaging ; Quaternary structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The hydroxylamine oxidoreductase from Nitrosomonas europaea was prepared to apparent electrophoretic homogeneity. Electron microscopy of negatively stained preparations of the sample revealed an overall diameter of about 8.8 nm of the enzyme particle. The native structure was determined as a tetrahedron-like assembly of identical subunits exhibiting four protein masses.
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  • 23
    ISSN: 1432-1173
    Keywords: Schlüsselwörter Morbus Hailey-Hailey ; Pemphigus chronicus benignus familiaris ; Polymerasekettenreaktion ; Herpes-simplex-Virus ; Elektronenmikroskopie ; Histologie ; Key words Hailey-Hailey disease ; Benign familial pemphigus ; Polymerase chain reaction ; Herpes simplex virus ; Electron microscopy ; Histology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary A 49-year-old man suffered from Hailey-Hailey disease for several years. The patient presented with an acute exacerbation of the disease, which did not respond to oral treatment with high doses of glucocorticosteroids. A skin biopsy was taken and the histological examination indicated a viral infection. Herpes simplex virus was confirmed by electron microscopy (negative staining) and polymerase chain reaction (PCR). The PCR presents a sensitive and effective molecular-biological method for the diagnosis of viral infections.
    Notes: Zusammenfassung Es wird über einen 49jährigen Patienten berichtet, bei dem seit Jahren ein Morbus Hailey-Hailey bekannt ist. Bei einem Rezidiv der Erkrankung kam es trotz hoher Glukokortikosteroidgaben zu keiner Remission. Erst die erneute diagnostische Abklärung des Rezidivs durch eine Hautprobe ergab den Verdacht auf eine Herpessimplex-Virus-Infektion, die über elektronenmikroskopische Negativkontrastierung und über Polymerasekettenreaktion (PCR) bestätigt werden konnte. Anhand dieser Kasuistik wird auf ein neueres molekularbiologisches Verfahren hingewiesen, das eine sensitive und schnelle Methode zum Virusnachweis darstellt.
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  • 24
    ISSN: 1432-2307
    Keywords: Adult Niemann-Pick disease ; Generalized AL-amyloidosis ; Progressive liver failure ; Fibroblast culture ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We report a case in which an adult form of Niemann-Pick disease (type B of NPD) was associated with a rapidly progressive generalized AL amyloidosis of kappa type. Both diagnosis were made by biopsy, the NPD by bone marrow biopsy and fibroblast culture, the amyloidosis by liver biopsy. Malignant non-Hodgkin lymphoma was not found. The patient, a 67-year-old woman, died from hepatic coma subsequent to a progressive liver failure. We discuss possible relations between the lysosomal storage disease and the development and rapid progression of amyloidosis.
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  • 25
    ISSN: 1432-0878
    Keywords: Key words: Node of Ranvier ; Axon ; Horseradish peroxidase (HRP) ; Retrograde axonal transport ; Electron microscopy ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Horseradish peroxidase (HRP) was injected into the left dorsal column nuclei of adult cats. Large dorsal funiculi axons of the C3, C5, C8 and L7 segments were searched for HRP-activity after 12, 24, 36 and 48 h using light and electron microscopy. Accumulations of intra-axonal HRP-positive bodies occurred at nodes of Ranvier in the C3–C8 segments at 12, 24 and 36 h and in the L7 segments at 24, 36, and 48 h. The accumulations of HRP in three spatio-temporally different consecutive patterns, noted earlier at nodes of Ranvier in the peripheral nervous system (PNS) portion of feline alpha motor axons for more than 70 h after an intramuscular injection of the enzyme, were not observed in the present material. We suggest that the differences in the modes in which large PNS and CNS axons interact with retrogradely transported HRP are due to differences in the organization of the respective nodal regions. We also emphasize that endocytosis via axon terminals in the CNS normally represents uptake of material from an extracellular space which is controlled and protected by the blood-brain barrier. This is in contrast to endocytosis via axon terminals in a muscle, which represents uptake of material from an extracellular space openly exposed to influx of different substances from the blood stream.
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  • 26
    ISSN: 1432-0878
    Keywords: Key words: Lateral heart nerve ; FMRFamide ; Allatostatin ; Coexistence ; Mirror-section ; Axosomatic synapses ; Electron microscopy ; Periplaneta americana (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Both allatostatin immunoreactivity (AS-IR) and FMRFamide immunoreactivity (FMRFa-IR) have been demonstrated light-microscopically in the lateral heart nerve of Periplaneta americana. The identical labeling of some fibers suggests the coexistence of the two antigens. Electron-microscopically, six granule types in the peripheral part of the lateral heart nerve can be distinguished according to their size and density (types 1–6). These granule types can be subdivided immunocytochemically by means of a new mirror-section technique. Granules of types 4 and 5 always exclusively show FMRFa-IR. In the populations of fibers containing granules of types 1 and 6, axon profiles can be found that contain granules colocalizing FMRFa-IR and AS-IR. Other axon profiles of these populations only contain immunonegative granules of the same ultrastructure. Granules of type 2 can be differentiated immunocytochemically in three forms in the same section: In some fibers, they are nonreactive; in other fibers of the same section, they show FMRFa – IR, whereas in a third fiber type, granules show AS – IR. Finally, granules of type 3 can be observed with FMRFa-IR. In other fibers, they occur with the same ultrastructure but exhibit no immunoreactivity. Two soma types occur in the lateral heart nerve. Soma type I is characterized by the production of electron-dense granules that show FMRFa-IR. Type II is in close contact with various fibers, forming different types of axosomatic synapses, hitherto unknown in Insecta.
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  • 27
    ISSN: 1432-0878
    Keywords: Key words: Spermatozoa ; Acrosome ; Thiols ; Disulphides ; Electron microscopy ; Monomaleimido nanogold ; Macropus eugenii (Marsupialia)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. This study utilised a commercially available monomaleimido-nanogold reagent to directly label cellular thiol groups (SH) of marsupial (tammar wallaby) spermatozoa before and after reduction of disulphides (S-S) with mercaptoethylamine hydrochloride (MEA). The sperm surface, mitochondrial membranes, axoneme and tail fibres were all labelled with gold particles before MEA treatment and the label intensity was increased after S-S reduction. The acrosomal membranes and matrix of spermatozoa contained no detectable SH prior to MEA treatment. However, after moderate MEA treatment (1 mg/ml) gold label was associated with the acrosomal membrane and invaginated acrosomal membrane within the acrosomal matrix. After exposure to 5 and 10 mg/ml MEA, gold particles heavily labelled the acrosomal matrix. Thus, the acrosomal membranes and matrix of tammar wallaby spermatozoa both contain S-S cross-linked structures, and this may contribute to the unusual stability of the marsupial acrosome. Under all treatment conditions the nucleus remained unlabelled. This is consistent with early studies which indicated that cysteine was absent from the nuclear protamines. The study also demonstrated that monomaleimido-nanogold can be used to resolve SH- and S-S-rich cellular structures directly, in addition to its use to label antibodies and Fab fragments for immunochemical localisation.
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  • 28
    ISSN: 1432-0878
    Keywords: Somatotrophs ; Growth hormone ; Growth hormone-releasing factor ; Secretory granule ; Electron microscopy ; Morphometry ; Rat (Fischer 344)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The anterior pituitary tissue of male rats injected with growth hormone-releasing factor (GRF) was either processed for stereology at the light-and electron-microscopic levels, or homogenized for growth hormone (GH) assay 2–60 min after GRF injection. Secretory granules of somatotrophs became smaller but increased in numerical density 2 min after GRF injection. Their volume density began to increase at 5 min. The frequency of exocytosis of the granules was most prominent as early as 2 min after GRF injection and reduced thereafter. GH levels in the tissue were lowest at 2–5 min, and returned to the control value by 60 min. Serum GH levels were highest at 15 min; even at 60 min, this value was higher than in the controls. These findings suggest that secretory granules in somatotrophs are stimulated to divide by GRF, resulting in a decrease in size and an increase in number. The discrepancy between the earlier formation of new secretory granules and the later restoration of intracellular GH levels implies that GRF first stimulates the synthesis of constituents of granules other than GH, and only later the synthesis of GH, and that newly formed small secretory granules contain less GH. From the clearance rate of serum GH and the frequency of granule exocytosis, it can be estimated that about a half million granules are released to maintain 1 ng/ml of serum GH in rats.
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  • 29
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 280 (1995), S. 183-188 
    ISSN: 1432-0878
    Keywords: Blood platelets ; Oxidized LDL ; Cytochalasin D ; Reflection contrast microscopy ; Image analysis ; Electron microscopy ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The adhesion of human blood platelets is studied with an in vitro model using reflection contrast microscopy and an image analysis system. The adhesive feature is promoted by oxidatively modified low density lipoprotein, which also induces functional morphological changes of platelets. However, when washed platelets are pretreated with 0.05 mM cytochalasin D, oxidized low density lipoprotein (100 μg/ml) causes a slower increase of the adhesion area (11.6 μm2/min) compared to untreated platelets (15.7 μm2/min) or platelets treated by oxidized low density lipoprotein alone (20.5 μm2/min, P〈0.01). These results are supported by light transmission analysis and by transmission electron microscopy. Our experiments suggest that cytochalasin D inhibits the change of platelets in shape induced by oxidized low density lipoprotein, hinders the adhesion, but does not prevent the adhesion entirely.
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  • 30
    ISSN: 1432-0878
    Keywords: Nitric oxide synthase ; Vasoactive intestinal peptide ; Immunohistochemistry ; Electron microscopy ; Submucous plexus ; Guinea-pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In the submucous plexus of the guinea-pig ileum, previous light-microscopic studies have revealed that vasoactive intestinal peptide (VIP)-immunoreactive and nitric oxide synthase (NOS)-immunoreactive terminals are found predominantly in association with VIP-immunoreactive nerve cell bodies. In this study, double-label immunohistochemistry at the light-microscopic level demonstrated co-localization of NOS-immunoreactivity and VIP-immunoreactivity in axon terminals in submucous ganglia. About 90% of nerve fibres with NOS-immunoreactivity or VIP-immunoreactivity were immunoreactive for both antigens; only about 10% of labelled varicosities contained only NOS-immunoreactivity or VIP-immunoreactivity. The VIP/NOS varicosities were more often seen in the central parts of the ganglia, close to the VIP-immunoreactive cell bodies. Ultrastructural immunocytochemistry with antibodies to VIP was used to determine if NOS/VIP terminals synapse exclusively with VIP-immunoreactive nerve cell bodies. We examined the targets of VIP-immunoreactive boutons in two submucous ganglia from different animals. Serial ultrathin sections were taken through the ganglia after they had been processed for VIP immunocytochemistry. For each cell body, the number of VIP inputs (synapses and close contacts) was determined. The number of VIP-immunoreactive synapses received by the cell bodies of submucous neurons varied from 0–4 and the number of VIP-immunoreactive close contacts varied from 3–10. There was no significant difference between VIP-immunoreactive nerve cell bodies and non-VIP nerve cell bodies in the number of VIP-immunoreactive synapses and close contacts they received. Thus, the implication from light microscopy that NOS/VIP terminals end predominantly on VIP nerve cells was not vindicated by electron microscopy.
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  • 31
    ISSN: 1432-0878
    Keywords: CD44, adhesion molecule ; Bone ; Osteoclasts ; Osteocytes ; Immunohistochemistry ; Confocal laser scanning microscopy ; Electron microscopy ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract CD44 is a multifunctional adhesion molecule that binds to hyaluronic acid, type I collagen, and fibronectin. We have studied the immunohistochemical localization of CD44 in bone cells by confocal laser scanning microscopy and transmission electron microscopy in order to clarify its role in the cell-cell and/or cell-matrix interaction of bone cells. In round osteoblasts attached to bone surfaces, immunoreactivity is restricted to their cytoplasmic processes. On the other hand, osteocytes in bone matrices show intense immunoreactivity on their plasma membrane. Intense immunoreactivity for CD44 can be detected on the basolateral plasma membranes of osteoclasts. There is considerably less reactivity observed in the area of the plasma membrane that is in direct contact with bone. The pre-embedding electron-microscopical method has revealed that CD44 is mainly localized on the basolateral plasma membrane of osteoclasts. However, the ruffled border and clear zone show little immunoreactivity. A CD44-positive reaction can be detected on both plasma membranes in the contact region between osteoclasts and osteocytes. These findings suggest that: 1) cells of the osteoblast lineage express CD44 in accordance with their morphological changes from osteoblasts into osteocytes; 2) osteoclasts express CD44 on their basolateral plasma membrane; 3) CD44 in osteoclasts and osteocytes may play an important role in cell-cell and/or cell-matrix attachment via extracellular matrices.
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  • 32
    ISSN: 1432-0878
    Keywords: Nitric oxide synthase ; Coronary vasculature ; Electron microscopy ; Immunocytochemistry Rat (sprague Dawley) ; Guinea-pig (Dunkin Hartley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Ultrastructural investigation of nitrix oxide synthase-immunoreactive nerves closely associated with blood vessels in rat and guinea-pig hearts revealed many labelled nerve fibres in the walls of the main branches of the coronary arteries, and in arterioles, capillaries and post-capillary venules. The number of nitric oxide synthase-containing nerve fibres associated with different vessels, even those of the same calibre, varied. Terminal regions of nitric oxide synthase-immunoreactive fibres were observed in the endocardium and myocardium. Nitric oxide synthase-labelled fibres displayed electrondense immunoproduct in both varicose and intervaricose regions. Immunoreactive axonal varicosities contained both small and large synaptic vesicles. The characteristics of the nitric oxide synthase-immunoreactive nerve fibres observed in the heart and the possibility that these fibres represent the processes of intracardiac neurones and/or sensory neurones of extrinsic origin are discussed.
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  • 33
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 281 (1995), S. 69-76 
    ISSN: 1432-0878
    Keywords: Periodic lamellar granule ; Primary granule ; Chronic myeloproliferative disorder ; Neutrophils ; Electron microscopy ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Granules consisting of periodically arranged membranous lamellae and amorphous electron-opaque material, i.e., periodic lamellar granules, are present in human neutrophils. To date, no extensive ultrastructural studies have been carried out on these granules because of their infrequent presence in neutrophils. The bone marrow of 18 cases of chronic myeloproliferative disorders, including one case of chronic neutrophilic leukemia in which periodic lamellar granules were frequently seen in neutrophils, was investigated by electron microscopy. Periodic lamellar granules were seen in neutrophils in 12 of the 18 cases at varying frequencies. They were preferentially seen in immature neutrophils. The transverse profiles of these granules revealed concentric complete/incomplete rings or periodic parallel straight lines, i.e., various patterns of lamellar arrangement were present. Periodic lamellar granules were positive for myeloperoxidase and lysozyme at the electron-microscopic level. These results suggest that these granules represent a primary neutrophil granule subtype. However, their functional and pathologic significance remains unknown.
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  • 34
    ISSN: 1432-0878
    Keywords: Key words: Ellipsoids ; Spleen ; Electron microscopy ; Fluorescent microspheres ; Oncorhynchus mykiss (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The ultrastructure of ellipsoids in the spleen of rainbow trout (Oncorhynchus mykiss) is described. The endothelium of terminations of arterioles bulged into the lumen, and gaps between the endothelial cells were evident. A continuous basal lamina was not present, and there were extensive interdigitations between the endothelial cells and surrounding reticular cells. The interdigitating processes were rich in microfilaments. Intravenously injected colloidal carbon, approximately 0.03 μm in diameter, was held in the reticular matrix of the ellipsoidal wall and taken up by macrophages that extended cellular processes among the reticular and endothelial cells. The intravenous injection of fluorescent polystyrene microspheres of known diameter showed that microspheres with a diameter of 0.5 or 1.0 μm were localised in the red pulp, whereas microspheres with a diameter of 0.15 μm were retained in ellipsoidal walls. Thus, the terminations of splenic arterioles in rainbow trout were found to be consistent with descriptions of ellipsoids in other vertebrates in that they possessed a specialised cuboidal endothelium, lacked a continuous basal lamina, were surrounded by a sheath of macrophages and reticular cells, and had a role in the selective filtration and retention of blood-borne particles.
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  • 35
    ISSN: 1432-0878
    Keywords: Lateral heart nerve ; FMRFamide ; Allatostatin ; Coexistence ; Mirror-section ; Axosomatic synapses ; Electron microscopy ; Periplaneta americana (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Both allatostatin immunoreactivity (AS-IR) and FMRFamide immunoreactivity (FMRFa-IR) have been demonstrated light-microscopically in the lateral heart nerve of Periplaneta americana. The identifical labeling of some fibers suggests the coexistence of the two antigens. Electron-microscopically, six granule types in the peripheral part of the lateral heart nerve can be distinguished according to their size and density (types 1–6). These granule types can be subdivided immunocytochemically by means of a new mirror-section technique. Granules of types 4 and 5 always exclusively show FMRFa-IR. In the populations of fibers containing granules of types 1 and 6, axon profiles can be found that contain granules colocalizing FMRFa-IR and AS-IR. Other axon profiles of these populations only contain immunonegative granules of the same ultrastructure. Granules of type 2 can be differentiated immunocytochemically in three forms in the same section: In some fibers, they are nonreactive; in other fibers of the same section, they show FMRFa-IR, whereas in a third fiber type, granules show AS-IR. Finally, granules of type 3 can be observed with FMRFA-IR. In other fibers, they occur with the same ultrastructure but exhibit no immunoreactivity. Two soma types occur in the lateral heart nerve. Soma type I is characterized by the production of electron-dense granules that show FMRFa-IR. Type II is in close contact with various fibers, forming different types of axosomatic synapses, hitherto unknown in Insecta.
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  • 36
    ISSN: 1432-0878
    Keywords: Suprachiasmatic nucleus ; Catecholamines ; Dopamine ; Electron microscopy ; Vasoactive intestinal peptide ; Vasopressin ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Catecholaminergic fibers in the suprachiasmatic nucleus of adult rats were investigated by use of light- and electron-microscopic immunocytochemistry. The suprachiasmatic nucleus receives a modest density of tyrosine hydroxylase-containing axons, homogeneously distributed in the nucleus and forming varicosities throughout its entire rostro-caudal extension. Immunolabeling with antibodies against dopamine showed that this catecholamine input comprises a dopaminergic component. Many tyrosine hydroxylase-positive cells were localized at the immediate periphery of the suprachiasmatic nucleus. With electron-microscopic examination, dendrites of these neurons were found within the limits of the nucleus as well as at a border zone between the suprachiasmatic nucleus proper and the optic tract where they received unlabeled synapses, providing a morphological support for a possible role of dopaminergic neurons in the integration and/or transfer of light-related signals. More than 91% of catecholaminergic axonal varicosities were found to establish morphologically defined synapses with dendrites. To investigate whether these synapses might be shared with neurons of one or both of the two main peptidergic populations of the nucleus, namely vasoactive intestinal peptide- and vasopressin-containing neurons, we carried out doublelabeling experments combining immunoperoxidase and immunogold-silver labeling. Results showed only a few cases of direct association of the catecholaminergic terminals with these peptidergic categories. In both types of dually stained sections, catecholaminergic synapses were preferentially made with unlabeled dendrites. The homogeneous distribution of tyrosine hydroxylase-immunoreactive fibers in the suprachiasmatic nucleus could therefore reflect a lack of significant catecholaminergic innervation of both vasoactive intestinal peptide- and vasopressin-synthesizing neurons.
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  • 37
    ISSN: 1432-0878
    Keywords: Pituitary ; Gonadotrops ; Crinophagy ; Electron microscopy ; Enzyme cytochemistry ; Immunocytochemistry ; Autoradiography ; Catfish, Clarias gariepinus (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The possible function of globules and irregular membrane-bound masses in the gonadotropin cells of the pituitary of Clarias gariepinus was studied. Strong secretory stimulation led to the disappearance of the secretory granules from gonadotropin cells but globules and irregular masses remained present. Acid phosphatase was detected enzyme-cytochemically in both globules and irregular masses. Radiolabelling with tritiated amino acids followed by autoradiography demonstrated that globules received radioactive material after secretory granules. The latter received radioactive material within 75 min of administration of radioactive amino acids but globules and irregular masses did not. Although some globules became radioactively labelled within 24 h of the administration of radioactive amino acids, irregular masses remained unlabelled during this period. Secretory granules reacted positively with antisera against α and β gonadotropin subunits, whereas globules and irregular masses only reacted with the antiserum against the β subunit. A moderate anti-7B2 immunoreactivity was demonstrated in secretory granules and globules, whereas irregular masses labelled strongly. The combined cytological results indicate that globules and irregular masses are degradative, possibly crinophagic structures which develop by fusional events from secretory granules to globules and then to irregular masses.
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  • 38
    ISSN: 1432-0878
    Keywords: Key words: Pituitary ; Gonadotrops ; Crinophagy ; Electron microscopy ; Enzyme cytochemistry ; Immunocytochemistry ; Autoradiography ; Catfish ; Clarias gariepinus (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The possible function of globules and irregular membrane-bound masses in the gonadotropin cells of the pituitary of Clarias gariepinus was studied. Strong secretory stimulation led to the disappearance of the secretory granules from gonadotropin cells but globules and irregular masses remained present. Acid phosphatase was detected enzyme-cytochemically in both globules and irregular masses. Radiolabelling with tritiated amino acids followed by autoradiography demons trated that globules received radioactive material after secretory granules. The latter received radioactive material within 75 min of administration of radioactive amino acids but globules and irregular masses did not. Although some globules became radioactively labelled within 24 h of the administration of radioactive amino acids, irregular masses remained unlabelled during this period. Secretory granules reacted positively with antisera against α and β gonadotropin subunits, whereas globules and irregular masses only reacted with the antiserum against the β subunit. A moderate anti-7B2 immunoreactivity was demonstrated in secretory granules and globules, whereas irregular masses labelled strongly. The combined cytological results indicate that globules and irregular masses are degradative, possibly crinophagic structures which develop by fusional events from secretory granules to globules and then to irregular masses.
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  • 39
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 280 (1995), S. 183-188 
    ISSN: 1432-0878
    Keywords: Key words: Blood platelets ; Oxidized LDL ; Cytochalasin D ; Reflection contrast microscopy ; Image analysis ; Electron microscopy ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The adhesion of human blood platelets is studied with an in vitro model using reflection contrast microscopy and an image analysis system. The adhesive feature is promoted by oxidatively modified low density lipoprotein, which also induces functional morphological changes of platelets. However, when washed platelets are pretreated with 0.05 mM cytochalasin D, oxidized low density lipoprotein (100 μg/ml) causes a slower increase of the adhesion area (11.6 μm2/min) compared to untreated platelets (15.7 μm2/min) or platelets treated by oxidized low density lipoprotein alone (20.5 μm2/min, P〈0.01). These results are supported by light transmission analysis and by transmission electron microscopy. Our experiments suggest that cytochalasin D inhibits the change of platelets in shape induced by oxidized low density lipoprotein, hinders the adhesion, but does not prevent the adhesion entirely.
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  • 40
    ISSN: 1432-0878
    Keywords: Key words: Suprachiasmatic nucleus ; Catecholamines ; Dopamine ; Electron microscopy ; Vasoactive intestinal peptide ; Vasopressin ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Catecholaminergic fibers in the suprachiasmatic nucleus of adult rats were investigated by use of light- and electron-microscopic immunocytochemistry. The suprachiasmatic nucleus receives a modest density of tyrosine hydroxylase-containing axons, homogeneously distributed in the nucleus and forming varicosities throughout its entire rostro-caudal extension. Immunolabeling with antibodies against dopamine showed that this catecholamine input comprises a dopaminergic component. Many tyrosine hydroxylase-positive cells were localized at the immediate periphery of the suprachiasmatic nucleus. With electron-microscopic examination, dendrites of these neurons were found within the limits of the nucleus as well as at a border zone between the suprachiasmatic nucleus proper and the optic tract where they received unlabeled synapses, providing a morphological support for a possible role of dopaminergic neurons in the integration and/or transfer of light-related signals. More than 91% of catecholaminergic axonal varicosities were found to establish morphologically defined synapses with dendrites. To investigate whether these synapses might be shared with neurons of one or both of the two main peptidergic populations of the nucleus, namely vasoactive intestinal peptide- and vasopressin-containing neurons, we carried out double-labeling experiments combining immunoperoxidase and immunogold-silver labeling. Results showed only a few cases of direct association of the catecholaminergic termin als with these peptidergic categories. In both types of dually stained sections, catecholaminergic synapses were preferentially made with unlabeled dendrites. The homogeneous distribution of tyrosine hydroxylase-immunoreactive fibers in the suprachiasmatic nucleus could therefore reflect a lack of significant catecholaminergic innervation of both vasoactive intestinal peptide- and vasopressin-synthesizing neurons.
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  • 41
    ISSN: 1432-0878
    Keywords: Key words: Thyro-parathyroidectomy ; Parathyroidectomy ; Enamel formation ; Light microscopy ; Electron microscopy ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The effects of thyro-parathyroidectomy, parathyroidectomy or thyroidectomy upon enamel formation in the rat incisor were studied. One control group and four groups of surgically treated rats were used: parathyroid autotransplanted, thyroidectomized, parathyroidectomized, and thyro-parathyroidectomized. One month after surgery, the incisors were processed for light and electron microscopy. The present study revealed perturbations of the Tomes’ process morphology, of the rod pattern in the inner enamel formation, of the enamel surface, and of the mineralization after thyro-parathyroidectomy. After parathyroidectomy, only mineralization defects could be visualised. No effects were observed in enamel after thyroidectomy. A severe hypocalcemic state as seen in thyro-parathyroidectomized rats affects the enamel shape, and mineralization, and the morphology and function of secretory ameloblasts. Knowledge of the way in which the alteration of the enamel surface is produced should contribute to a better understanding of the development of tooth enamel.
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  • 42
    ISSN: 1432-0878
    Keywords: Meninges ; Cerebrospinal fluid ; Electron microscopy ; Aging ; Multilamellar bodies ; Surfactant ; Goldfish ; Carassius auratus (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In the optic tectum of goldfish, the outer, middle and inner layers of the endomeninx were evident in animals ranging in age from 1 month to several years. The outer layer in young animals consisted of closely overlapping cells with intertwined processes, whereas in the older animals it contained large extracellular spaces. The intermediate layer cells were always arranged in a single continuous layer, but in young animals they overlapped extensively with one another toward their edges whereas in the oldest animals they became extremely flat and non-overlapping. The inner layer included an outer tier of cells with their bases adhering to the intermediate layer, and an inner tier of cells detached from both the intermediate layer and the basal lamina overlying the brain parenchyma. Inner layer cells contained many large vacuoles that were in continuity with the extracellular space. With age, the extracellular space and the vacuolar system expanded, and the inner layer evolved into a meshwork of attenuated cytoplasmic processes embedded in the granular extracellular matrix. Another age-related feature was the accumulation adjacent to the basal lamina of uniform disc-shaped membranous structures, resembling multilamellar bodies of lung surfactant. These “disc bodies” were apparently generated by the coalescence of vesicles formed at the surface of the inner layer cells, possibly as a by-product of protein secretion by these cells.
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  • 43
    ISSN: 1432-0878
    Keywords: Key words: Nitric oxide synthase ; Vasoactive intestinal peptide ; Immunohistochemistry ; Electron microscopy ; Submucous plexus ; Guinea-pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. In the submucous plexus of the guinea-pig ileum, previous light-microscopic studies have revealed that vasoactive intestinal peptide (VIP)-immunoreactive and nitric oxide synthase (NOS)-immunoreactive terminals are found predominantly in association with VIP-immunoreactive nerve cell bodies. In this study, double-label immunohistochemistry at the light-microscopic level demonstrated co-localization of NOS-immunoreactivity and VIP-immunoreactivity in axon terminals in submucous ganglia. About 90% of nerve fibres with NOS-immunoreactivity or VIP-immunoreactivity were immunoreactive for both antigens; only about 10% of labelled varicosities contained only NOS-immunoreactivity or VIP-immunoreactivity. The VIP/NOS varicosities were more often seen in the central parts of the ganglia, close to the VIP-immunoreactive cell bodies. Ultrastructural immunocytochemistry with antibodies to VIP was used to determine if NOS/VIP terminals synapse exclusively with VIP-immunoreactive nerve cell bodies. We examined the targets of VIP-immunoreactive boutons in two submucous ganglia from different animals. Serial ultrathin sections were taken through the ganglia after they had been processed for VIP immunocytochemistry. For each cell body, the number of VIP inputs (synapses and close contacts) was determined. The number of VIP-immunoreactive synapses received by the cell bodies of submucous neurons varied from 0–4 and the number of VIP-immunoreactive close contacts varied from 3–10. There was no significant difference between VIP-immunoreactive nerve cell bodies and non-VIP nerve cell bodies in the number of VIP-immunoreactive synapses and close contacts they received. Thus, the implication from light microscopy that NOS/VIP terminals end predominantly on VIP nerve cells was not vindicated by electron microscopy.
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  • 44
    ISSN: 1432-0878
    Keywords: Key words: CD44 ; adhesion molecule ; Bone ; Osteoclasts ; Osteocytes ; Immunohistochemistry ; Confocal laser scanning microscopy ; Electron microscopy ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. CD44 is a multifunctional adhesion molecule that binds to hyaluronic acid, type I collagen, and fibronectin. We have studied the immunohistochemical localization of CD44 in bone cells by confocal laser scanning microscopy and transmission electron microscopy in order to clarify its role in the cell-cell and/or cell-matrix interaction of bone cells. In round osteoblasts attached to bone surfaces, immunoreactivity is restricted to their cytoplasmic processes. On the other hand, osteocytes in bone matrices show intense immunoreactivity on their plasma membrane. Intense immunoreactivity for CD44 can be detected on the basolateral plasma membranes of osteoclasts. There is considerably less reactivity observed in the area of the plasma membrane that is in direct contact with bone. The pre-embedding electron-microscopical method has revealed that CD44 is mainly localized on the basolateral plasma membrane of osteoclasts. However, the ruffled border and clear zone show little immunoreactivity. A CD44-positive reaction can be detected on both plasma membranes in the contact region between osteoclasts and osteocytes. These findings suggest that: 1) cells of the osteoblast lineage express CD44 in accordance with their morphological changes from osteoblasts into osteocytes; 2) osteoclasts express CD44 on their basolateral plasma membrane; 3) CD44 in osteoclasts and osteocytes may play an important role in cell-cell and/or cell-matrix attachment via extracellular matrices.
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  • 45
    ISSN: 1432-0878
    Keywords: Key words: Nitric oxide synthase ; Coronary vasculature ; Electron microscopy ; Immunocytochemistry ; Rat (Sprague Dawley) ; Guinea-pig (Dunkin Hartley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Ultrastructural investigation of nitric oxide synthase-immunoreactive nerves closely associated with blood vessels in rat and guinea-pig hearts revealed many labelled nerve fibres in the walls of the main branches of the coronary arteries, and in arterioles, capillaries and post-capillary venules. The number of nitric oxide synthase-containing nerve fibres associated with different vessels, even those of the same calibre, varied. Terminal regions of nitric oxide synthase-immunoreactive fibres were observed in the endocardium and myocardium. Nitric oxide synthase-labelled fibres displayed electron-dense immunoproduct in both varicose and intervaricose regions. Immunoreactive axonal varicosities contained both small and large synaptic vesicles. The characteristics of the nitric oxide synthase-immunoreactive nerve fibres observed in the heart and the possibility that these fibres represent the processes of intracardiac neurones and/or sensory neurones of extrinsic origin are discussed.
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  • 46
    Electronic Resource
    Electronic Resource
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    Cell & tissue research 281 (1995), S. 69-76 
    ISSN: 1432-0878
    Keywords: Key words: Periodic lamellar granule ; Primary granule ; Chronic myeloproliferative disorder ; Neutrophils ; Electron microscopy ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Granules consisting of periodically arranged membranous lamellae and amorphous electron-opaque material, i.e., periodic lamellar granules, are present in human neutrophils. To date, no extensive ultrastructural studies have been carried out on these granules because of their infrequent presence in neutrophils. The bone marrow of 18 cases of chronic myeloproliferative disorders, including one case of chronic neutrophilic leukemia in which periodic lamellar granules were frequently seen in neutrophils, was investigated by electron microscopy. Periodic lamellar granules were seen in neutrophils in 12 of the 18 cases at varying frequencies. They were preferentially seen in immature neutrophils. The transverse profiles of these granules revealed concentric complete/incomplete rings or periodic parallel straight lines, i.e., various patterns of lamellar arrangement were present. Periodic lamellar granules were positive for myeloperoxidase and lysozyme at the electron-microscopic level. These results suggest that these granules represent a primary neutrophil granule subtype. However, their functional and pathologic significance remains unknown.
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  • 47
    ISSN: 1432-0878
    Keywords: Key words: Blood platelets ; Immunocytochemistry ; Electron microscopy ; Coated vesicles ; Clathrin ; Adhesive proteins ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Coated membranes and vesicles play an important role in receptor-mediated endocytosis and intracellular trafficking in various cell types, and are also present in blood platelets. Platelets take up certain proteins from the blood plasma, such as von Willebrand factor and fibrinogen, and these substances are transferred to storage granules. The receptors for these plasma proteins on the platelet plasma membrane have been well characterized, but morphological evidence for their transport to the storage granules is not yet available. In an attempt to clarify this aspect, we employed postembedding immunocytochemistry on platelets embedded in the acrylic resin LR White. Clathrin as the major coat component of coated vesicles was localized in the cytoplasm, on the plasmic faces of α-granules and the open canalicular system, and on the plasmic face of the plasma membrane. Colocalizations of the adhesive proteins, von Willebrand factor, fibrinogen and fibronectin, with clathrin could be observed at the same typical locations as coated vesicles were seen in Araldite-embedded material. These colocalizations have not been reported to date and furnish further evidence for a coated vesicle-mediated transport of blood plasma-derived adhesive proteins from their receptors on the outer plasma membrane to the α-granules.
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  • 48
    ISSN: 1432-0878
    Keywords: Key words: Meninges ; Cerebrospinal fluid ; Electron microscopy ; Aging ; Multilamellar bodies ; Surfactant ; Goldfish ; Carassius auratus (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. In the optic tectum of goldfish, the outer, middle and inner layers of the endomeninx were evident in animals ranging in age from 1 month to several years. The outer layer in young animals consisted of closely overlapping cells with intertwined processes, whereas in the older animals it contained large extracellular spaces. The intermediate layer cells were always arranged in a single continuous layer, but in young animals they overlapped extensively with one another toward their edges whereas in the oldest animals they became extremely flat and non-overlapping. The inner layer included an outer tier of cells with their bases adhering to the intermediate layer, and an inner tier of cells detached from both the intermediate layer and the basal lamina overlying the brain parenchyma. Inner layer cells contained many large vacuoles that were in continuity with the extracellular space. With age, the extracellular space and the vacuolar system expanded, and the inner layer evolved into a meshwork of attenuated cytoplasmic processes embedded in the granular extracellular matrix. Another age-related feature was the accumulation adjacent to the basal lamina of uniform disc-shaped membranous structures, resembling multilamellar bodies of lung surfactant. These ”disc bodies” were apparently generated by the coalescence of vesicles formed at the surface of the inner layer cells, possibly as a by-product of protein secretion by these cells.
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  • 49
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    Cell & tissue research 279 (1995), S. 445-452 
    ISSN: 1432-0878
    Keywords: Key words: Estradiol receptor ; Breast cancer cells ; Cell culture ; Ultrastructure ; Electron microscopy ; Immunohistochemistry ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: 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.
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  • 50
    Electronic Resource
    Electronic Resource
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    Cell & tissue research 279 (1995), S. 445-452 
    ISSN: 1432-0878
    Keywords: Estradiol receptor ; Breast cancer cells ; Cell culture ; Ultrastructure ; Electron microscopy ; Immunohistochemistry ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: 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.
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  • 51
    ISSN: 1432-0878
    Keywords: Blood platelets ; Immunocytochemistry ; Electron microscopy ; Coated vesicles ; Clathrin ; Adhesive proteins ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Coated membranes and vesicles play an important role in receptor-mediated endocytosis and intracellular trafficking in various cell types, and are also present in blood platelets. Platelets take up certain proteins from the blood plasma, such as von Willebrand factor and fibrinogen, and these substances are transferred to storage granules. The receptors for these plasma proteins on the platelet plasma membrane have been well characterized, but morphological evidence for their transport to the storage granules is not yet available. In an attempt to clarify this aspect, we employed postembedding immunocytochemistry on platelets embedded in the acrylic resin LR White. Clathrin as the major coat component of coated vesicles was localized in the cytoplasm, on the plasmic faces of α-granules and the open canalicular system, and on the plasmic face of the plasma membrane. Colocalizations of the adhesive proteins, von Willebrand factor, fibrinogen and fibronectin, with clathrin could be observed at the same typical locations as coated vesicles were seen in Araldite-embedded material. These colocalizations have not been reported to date and furnish further evidence for a coated vesicle-mediated transport of blood plasma-derived adhesive proteins from their receptors on the outer plasma membrane to the α-granules.
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  • 52
    ISSN: 1432-0878
    Keywords: Ellipsoids ; Spleen ; Electron microscopy ; Fluorescent microspheres ; Oncorhynchus mykiss (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The ultrastructure of ellipsoids in the spleen of rainbow trout (Oncorhynchus mykiss) is described. The endothelium of terminations of arterioles bulged into the lumen, and gaps between the endothelial cells were evident. A continuous basal lamina was not present, and there were extensive interdigitations between the endothelial cells and surrounding reticular cells. The interdigitating processes were rich in microfilaments. Intravenously injected colloidal carbon, approximately 0.03 μm in diameter, was held in the reticular matrix of the ellipsoidal wall and taken up by macrophages that extended cellular processes among the reticular and endothelial cells. The intravenous injection of fluorescent polystyrene microspheres of known diameter showed that microspheres with a diameter of 0.5 or 1.0 μm were localised in the red pulp, whereas microspheres with a diameter of 0.15 μm were retained in ellipsoidal walls. Thus, the terminations of splenic arterioles in rainbow trout were found to be consistent with descriptions of ellipsoids in other vertebrates in that they possessed a speciallised cuboidal endothelium, lacked a continuous basal lamina, were surrounded by a sheath of macrophages and reticular cells, and had a sheath of macrophages and reticular cells, and had a role in the selective filtration and retention of bloodborne particles.
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  • 53
    ISSN: 1432-0878
    Keywords: Spermatozoa ; Acrosome ; Thiols ; Disulphides ; Electron microscopy ; Monomaleimido nanogold ; Macropus eugenii (Marsupialia)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract This study utilised a commercially available monomaleimido-nanogold reagent to directly label cellular thiol groups (SH) of marsupial (tammar wallaby) spermatozoa before and after reduction of disulphides (S-S) with mercaptoethylamine hydrochloride (MEA). The sperm surface, mitochondrial membranes, axoneme and tail fibres were all labelled with gold particles before MEA treatment and the label intensity was increased after S-S reduction. The acrosomal membranes and matrix of spermatozoa contained no detectable SH prior to MEA treatment. However, after moderate MEA treatment (1 mg/ml) gold label was associated with the acrosomal membrane and invaginated acrosomal membrane within the acrosomal matrix. After exposure to 5 and 10 mg/ml MEA, gold particles heavily labelled the acrosomal matrix. Thus, the acrosomal membranes and matrix of tammar wallaby spermatozoa both contain S-S cross-linked structures, and this may contribute to the unusual stability of the marsupial acrosome. Under all treatment conditions the nucleus remained unlabelled. This is consistent with early studies which indicated that cysteine was absent from the nuclear protamines. The study also demonstrated that monomaleimido-nanogold can be used to resolve SH- and S-S-rich cellular structures directly, in addition to its use to label antibodies and Fab fragments for immunochemical localisation.
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  • 54
    ISSN: 1432-0878
    Keywords: Key words: Somatotrophs ; Growth hormone ; Growth hormone-releasing factor ; Secretory granule ; Electron microscopy ; Morphometry ; Rat (Fischer 344)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The anterior pituitary tissue of male rats injected with growth hormone-releasing factor (GRF) was either processed for stereology at the light- and electron-microscopic levels, or homogenized for growth hormone (GH) assay 2–60 min after GRF injection. Secretory granules of somatotrophs became smaller but increased in numerical density 2 min after GRF injection. Their volume density began to increase at 5 min. The frequency of exocytosis of the granules was most prominent as early as 2 min after GRF injection and reduced thereafter. GH levels in the tissue were lowest at 2–5 min, and returned to the control value by 60 min. Serum GH levels were highest at 15 min; even at 60 min, this value was higher than in the controls. These findings suggest that secretory granules in somatotrophs are stimulated to divide by GRF, resulting in a decrease in size and an increase in number. The discrepancy between the earlier formation of new secretory granules and the later restoration of intracellular GH levels implies that GRF first stimulates the synthesis of constituents of granules other than GH, and only later the synthesis of GH, and that newly formed small secretory granules contain less GH. From the clearance rate of serum GH and the frequency of granule exocytosis, it can be estimated that about a half million granules are released to maintain 1 ng/ml of serum GH in rats.
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  • 55
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    European archives of oto-rhino-laryngology and head & neck 252 (1995), S. 239-243 
    ISSN: 1434-4726
    Keywords: Homograft auditory ossicles ; Preservative solutions ; Shelf life ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The ultrastructure of preserved ossicles at different shelf lives was compared. Homograft ossicles were harvested and preserved in 70% alcohol, 1:5000 Cialit (sodium-2-ethyl-mercuri-mercapto-benzoxazole-5-carboxylate), and buffered 4% formaldehyde at pH 7. The ultrastructure of each ossicle was studied by both scanning and transmission electron microscopy and was compared to that of fresh controls placed in 0.9 N saline solution. The results indicated clearly the superiority of 70% alcohol as a long-term preservative and 1:5000 Cialit as a short-term preservative.
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  • 56
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    European archives of oto-rhino-laryngology and head & neck 252 (1995), S. 469-474 
    ISSN: 1434-4726
    Keywords: Reinke's laryngeal edema ; Electron microscopy ; Immunohistochemistry ; Pathogenesis Neobursa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Light microscopy of vocal cord mucosa in patients with Reinke's edema revealed highly ramified fissured spaces in the subepithelial tissue that were generally lined with flat cells. The ultrastructure of the parietal cells resembled fibroblasts whose cytoplasmic extensions overlapped in two to three layers in some places. Cell contacts were not observed. Neither electron microscopy nor immunohistochemical testing with antibody against laminin demonstrated a basal membrane. It was possible to distinguish between light and dark cells in the specimens examined. The cytoplasm of the light cells contained intermediate filaments, mitochondria, lysosomes, coated vesicles, caveolae and broad cisternae of rough endoplasmic reticulum. The dark cells were more numerous and typically exhibited a well-developed endoplasmic reticulum and free ribosomes. The parietal cells showed no immunoreaction against human vascular endothelial cells. Immunohistochemical demonstration of mesenchymal intermediate filaments using antibody against vimentin yielded a positive reaction for some of the cells in the walls of the crevices and subepithelial tissue. It was also possible to demonstrate a few cells with monoclonal antibody against macrophages (KiM6). These findings contradict the concept of lymphatic distension in cases of Reinke's edema. Since the parietal cells seen resembled synoviocytes in their structure and immunohistochemical reactions, findings indicate that the hollow spaces of Reinke's edema develop like neobursae from mechanical strain.
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  • 57
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    European archives of oto-rhino-laryngology and head & neck 252 (1995), S. 229-235 
    ISSN: 1434-4726
    Keywords: Larynx ; Neuroendocrine carcinoma ; Carcinoid tumor ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Carcinoid tumors belong to the group of neuroendocrine tumors of epithelial origin, i.e., neuroendocrine carcinomas. These neoplasms usually occur in the gastrointestinal tract or bronchial system but are very rare neoplasms in the larynx. Since carcinoid tumors in this latter site may appear to be undifferentiated by light microscopy, they may possibly be misinterpreted and their neuroendocrine characteristics may remain unrecognized. Using immunohistochemical methods, three carcinoid tumors were studied and showed positive immunostaining for markers of epithelial origin (cytokeratins, epithelial membrane antigen, carcino-embryonic antigen) and, in particular, for markers of neuroendocrine differentiation (chromogranin, synaptophysin, neuron-specific enolase). All tumors expressed calcitonin-, serotonin- and adrenocorticotropic-hormone-like immunoreactivity. In contrast, three poorly differentiated squamous cell carcinomas showed positive immunostaining for epithelial markers but did not show any immunoreactivity with markers of endocrine characteristics. Fine structurally, carcinoid tumor cells contained neurosecretory-type granules scattered throughout the cytoplasm. The present study demonstrated that (1) carcinoid tumors of the larynx possess distinct immunohistochemical characteristics that allow a clear classification, (2) it is advisable to use a battery of primary antibodies rather than rely on specificity and sensitivity of a single marker to establish diagnosis and (3) the fine structural demonstration of neurosecretory-type granules serves as a reliable adjunct to diagnosis.
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  • 58
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    European archives of oto-rhino-laryngology and head & neck 252 (1995), S. 53-56 
    ISSN: 1434-4726
    Keywords: Parotid gland ; Amyloidosis ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A case of an organ-limited amyloid tumor of the left parotid gland is described with a history of recurrence. A slowly growing parotid mass was the only symptom. After 5.5 years following local excision, the patient was readmitted with a slowly growing recurrence in the superficial lobe of the previously treated gland. Lateral parotidectomy was performed with wide excision of the infiltrated tissue and preservation of the facial nerve. Primary amyloidosis of the AL type was confirmed with immunohistochemical studies revealing staining for lambda but not kappa light chains of immunoglobulins. There has been no clinical or laboratory evidence of systemic amyloidosis or recurrence after 2 years. To the best of our knowledge, this is the first report of a recurrent amyloid tumor of the parotid gland.
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  • 59
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    European archives of oto-rhino-laryngology and head & neck 252 (1995), S. 249-254 
    ISSN: 1434-4726
    Keywords: Middle ear ; Glycoconjugate ; Wheat germ agglutinin ; Electron microscopy ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To evaluate the protective function of the mucous blanket (MB) against lectin substances, we examined at the ultrastructural level whether intraluminal colloidal gold-labelled wheat germ agglutinin (WGA) could enter the MB-covered epithelial cell surface of the guinea pig tubotympanic mucosa. Post-embedding staining with WGA/gold on thin tissue sections was done in parallel for comparison. The cell surface glycoconjugate of the eustachian tubal and transitional epithelium had a typical bilayered structure: the outer MB and the microvilli-associated glycocalyx (MAG), which were interposed by the interciliary fluid zone. In squamous epithelium of the distal middle ear, the MB adhered to the MAG, thereby forming a monolayered coat of glycoconjugates at the cell surface. In the pre-embedding staining, WGA/gold did not bind with the MB and MAG in the eustachian tube, and exclusively bound with MB in the transitional area. Direct binding was also found with MAG and the apical plasmic membrane in the squamous epithelium. These findings indicate that MAG is occluded by MB lined with the interciliary fluid zone for luminal access of lectin at the proximal lumina of the tubotympanic epithelium. It is also suggested that MB existing at two sites possesses a different WGA-binding capacity: shielding as a “dust cover” in the eustachian tube and entrapping as a “flypaper” against lectin in the transitional area of the middle ear.
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  • 60
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 61
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 29-34 
    ISSN: 0009-2940
    Keywords: Tripodal ligands ; Triamidostannates ; Metal-metal bonds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 1 Ill.
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  • 62
    ISSN: 0009-2940
    Keywords: Selenium-nitrogen compounds ; Sulfur-nitrogen compounds ; Calculations, ab initio ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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).
    Additional Material: 8 Ill.
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  • 63
    ISSN: 0009-2940
    Keywords: Ruthenium(II) complexes, octahedral ; Phosphino esters as mono- and bidentate ligands ; Fluxional behaviour ; Carbene complexes ; Vinylidene complexes ; Allenylidene complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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
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  • 64
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 81-85 
    ISSN: 0009-2940
    Keywords: Aluminium-aluminium bond ; Insertion of trimethylsilyl azide ; Trimeric dialkylaluminium azide ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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).
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  • 65
    ISSN: 0009-2940
    Keywords: Poly(azolyl)borates, metal complexes of ; Bis(tetrazolyl)borate, metal complexes of ; Metal-nitrogen coordination ; Coordination polymers ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 8 Ill.
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  • 66
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 365-371 
    ISSN: 0009-2940
    Keywords: Cumulenes ; Butadienes ; Vinylcyclopropane ; Vinylidenecyclopropane ; Bicyclopropyl, phosphanyl-substituted ; Cyclopropanation ; Phosphane ligands ; Phosphane chalcogenides ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 5 Ill.
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  • 67
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 413-416 
    ISSN: 0009-2940
    Keywords: Ferriophosphanes ; Ferriophosphoranes ; Thioxophosphane ligand ; Decarbonylation reaction ; Sulfurization ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 3 Ill.
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  • 68
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 435-436 
    ISSN: 0009-2940
    Keywords: Trifluoromethylthio group ; Carbenium ions ; Diphenylmethane ; Dyes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
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  • 69
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 441-442 
    ISSN: 0009-2940
    Keywords: Diphosphane disulfides ; Metallophosphoranes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 1 Ill.
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  • 70
    ISSN: 0009-2940
    Keywords: 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
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 4 Ill.
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  • 71
    ISSN: 0009-2940
    Keywords: Manganese ; Cycloheptadienyl ; Alkyne ; [5+2],homo[5+2] Cycloadditions ; Tricyclo[5.3.1.04,10]undeca-2,5-dien-11-yl ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 1 Ill.
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  • 72
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 73
    ISSN: 0009-2940
    Keywords: Anellated azaphospholes ; Hantzsch-type [3 + 2] cyclocondensation ; Chloromethyldichlorophosphane ; Regioselectivity ; 31P-, 1H-, 13C-NMR spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 6 Tab.
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  • 74
    ISSN: 0009-2940
    Keywords: Reductive silylation ; Aminochlorophosphanes ; Silylphosphanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 1 Ill.
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  • 75
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 641-643 
    ISSN: 0009-2940
    Keywords: Carbene ligands ; Tungsten complexes ; 2,2′-Bifuran ; Copper coupling reaction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 1 Tab.
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  • 76
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 679-687 
    ISSN: 0009-2940
    Keywords: Stannole, diethylboryl-substituted ; Trimethyltin alkoxides ; 2-, 3-Stannolenes, organometallic-substituted ; NMR, coupling constants, 2J(Sn,Sn), sign determination ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 3 Ill.
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  • 77
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 751-762 
    ISSN: 0009-2940
    Keywords: 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
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 7 Ill.
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  • 78
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 741-742 
    ISSN: 0009-2940
    Keywords: Selenenyl halides ; Nucleophilic substitution ; Complex intermediate ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 1 Tab.
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  • 79
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 779-785 
    ISSN: 0009-2940
    Keywords: Zinc complexes ; Drug ligands ; Captopril ; Isoniazid ; Nalidixic acid ; Mercaptopurine ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 4 Ill.
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  • 80
    ISSN: 0009-2940
    Keywords: Phosphate-phosphonate rearrangement ; Carbanions, benzylic, configurational stability of ; Phosphonaes Lithium amides, homochiral ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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%.
    Additional Material: 1 Tab.
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  • 81
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 845-850 
    ISSN: 0009-2940
    Keywords: Phenanthroline synthesis ; Tris(phenanthroline)iron(II) complexes ; Redox potential ; Cyclic voltammetry ; Electron transfer, outer-sphere ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 1 Ill.
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  • 82
    ISSN: 0009-2940
    Keywords: Bis(cyclopentadienyl)methane ; Heterobimetallic complexes ; Imido complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
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  • 83
    ISSN: 0009-2940
    Keywords: Fullerene ; Hydrofulleride ; Manganese complex ; Rhenium complex ; Iron complexes ; Ruthenium complex ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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)]+.
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  • 84
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    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1083-1088 
    ISSN: 0009-2940
    Keywords: Silenes ; Silene dimerization ; 1,2-Disilacyclobutanes ; 1,3-Disilacyclobutanes ; 2,3-Disilanaphthalene, tetrahydro- ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 2 Ill.
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  • 85
    ISSN: 0009-2940
    Keywords: 1,7-Dimethylocta-2,6-diene-1,8-diyl ; Ruthenium complexes ; α-Amino carboxylates ; α-Amino acid esters ; Peptide esters ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
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  • 86
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1135-1136 
    ISSN: 0009-2940
    Keywords: Hemilabile ligands ; Cyclopentadienyl ligands, functionalised ; Iron compounds ; Halfsandwich complex ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
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  • 87
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1145-1148 
    ISSN: 0009-2940
    Keywords: P2, As2, P2S2, and P2Se2 ligands ; Iron complexes ; Triangulated dodecahedra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 3 Ill.
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  • 88
    ISSN: 0009-2940
    Keywords: Synthesis, stereoselective ; Catalysis ; Tetrahydrofurans ; Dialkylzinc reagents ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 1 Tab.
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  • 89
    ISSN: 0009-2940
    Keywords: 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
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
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  • 90
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1061-1068 
    ISSN: 0009-2940
    Keywords: N-Isocyanides ; N-Isocyanodialkylamine complexes ; Carbene complexes ; Imaging-Plate data collection ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
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  • 91
    ISSN: 0009-2940
    Keywords: [2.2.2]Paracyclophanes ; Polyenes ; Silver complexes ; X-Ray structural analysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
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  • 92
    Electronic Resource
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1095-1103 
    ISSN: 0009-2940
    Keywords: Zinc complexes ; Tridentate ligands ; Tris(pyrazolyl)methane ; Reactivity ; Structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 5 Ill.
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  • 93
    ISSN: 0009-2940
    Keywords: Metallomacrocycles ; Nickel complexes ; Complexation reactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 2 Ill.
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  • 94
    ISSN: 0009-2940
    Keywords: Silicon transition metal complexes ; Metallodisilanes ; Nucleophilic metallation ; Cl/H exchange at silicon ; Raman spectroscopy ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
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  • 95
    Electronic Resource
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1137-1139 
    ISSN: 0009-2940
    Keywords: Tetraindane(4) ; Indium(I) ; Mn-Mn bond ; Indium alkyl bridge ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
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  • 96
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1149-1156 
    ISSN: 0009-2940
    Keywords: Selenoaldehyde complex ; Thioselonocarboxylic ester complexes ; Selenetane complex ; Dihydrodiselenine complex ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
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  • 97
    ISSN: 0009-2940
    Keywords: Electrophilic aromatic substitution ; Electrophilic vinylic substitution ; Trialkylstannanes, application of ; Sulfonamides, synthesis of ; Sulfodestannylation, application of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
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  • 98
    Electronic Resource
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1207-1219 
    ISSN: 0009-2940
    Keywords: 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
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
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  • 99
    ISSN: 0009-2940
    Keywords: Oxofunctionalization ; Dimethyldioxirane ; Metallo silanes ; Metallo silanols ; Metallo siloxanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
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  • 100
    ISSN: 0009-2940
    Keywords: Phosphaalkenes, C-halo, C-metal ; Phosphaacrylic acid ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
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