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  • 1990-1994  (754)
  • 1975-1979
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  • 1945-1949
  • 1940-1944
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  • 1990  (754)
  • Inorganic Chemistry  (693)
  • Electron microscopy
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  • 1990-1994  (754)
  • 1975-1979
  • 1970-1974
  • 1945-1949
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  • 1
    Electronic Resource
    Electronic Resource
    Giant inflammatory polyps associated with idiopathic inflammatory bowel disease (1990)
    Springer
    Diseases of the colon & rectum 33 (1990), S. 773-777 
    Details
    ISSN: 1530-0358
    Keywords: Giant inflammatory polyp ; Idiopathic inflammatory bowel disease ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Five cases of giant inflammatory polyps associated with idiopathic inflammatory bowel disease are reported. Polyps produced intestinal obstruction in three cases; consequently, surgery was performed. In a further two cases, intestinal bleeding was improved by endoscopic polypectomy. Electron microscopy showed fibroblasts, myofibroblasts, mast cells, lymphocytes, collagen fibers, capillaries, and venules. Remnants of the original mucosal epithelial cells, smooth muscle cells, and hypertrophic autonomous nerve plexuses were noted. Nerve fibers were interwoven with the matrix of the polyps. Mast cells were closely linked with vessels, nerves, and collagen fibers. They may have an important role in the excessive granulation, angiogenesis, and fibrotic process in giant inflammatory polyps.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02052325
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  • 2
    Electronic Resource
    Electronic Resource
    A monoclonal antibody (Mab 67) marks type B synoviocytes (1990)
    Springer
    Rheumatology international 10 (1990), S. 103-106 
    Details
    ISSN: 1437-160X
    Keywords: Synovium ; Synoviocytes ; Monoclonal antibody ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The functionally important lining cells of the synovium (types A and B synoviocytes) are the subjects of much study but have presented problems with their characterization and microscopical identification, particularly at the light level. Type A (macrophage-like) synoviocytes, however are more easily localized than the type B (fibroblast-like) variety because of the greater availability of antimacrophage antisera. We describe, using light and electron microscopy, a monoclonal antibody which in the synovial intimal layer is specific for type B synoviocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02274823
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  • 3
    Electronic Resource
    Electronic Resource
    Cellular schwannoma (1990)
    Springer
    Virchows Archiv 416 (1990), S. 237-248 
    Details
    ISSN: 1432-2307
    Keywords: Neurilemoma ; Pseudosarcoma ; Electron microscopy ; Immunohistochemistry ; Cytogenetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A series of 29 cellular schwannomas is described in terms of their clinical presentation and course, light and electron-microscopic appearance, immunohistochemical properties and cytogenetics. The study indicates that cellular schwannoma can be defined as a subtype of classical schwannoma, characterized by spindle cells forming a compact fascicular, sometimes fibrosarcoma-like growth pattern, a low mitotic activity, a generally moderate nuclear and cellular polymorphism and a high degree of Schwann cell differentiation as seen by electron microscopy and immunohistochemistry. The tumour is characteristically located close to the vertebral column, in the mediastinum or retroperitoneum and has a benign course. Occasionally bone destruction and neurological symptoms develop. The clinical appearance together with the high cellularity, fascicular pattern and mitotic activity had led to the erroneous diagnosis of a soft tissue sarcoma in a few cases, and cellular schwannoma may thus be considered to be a pseudosarcoma. Immunohistochemically, cellular schwannomas appear to deviate from classical schwannomas and malignant peripheral nerve sheath tumours by their expression of glial fibrillary acidic protein. The chromosome analysis revealed a normal diploid stemline karyotype, with a variety of abnormal clones, including one with monosomy 22.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01678983
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  • 4
    Electronic Resource
    Electronic Resource
    Non-functional malignant paraganglioma of the stomach (1990)
    Springer
    Virchows Archiv 417 (1990), S. 261-266 
    Details
    ISSN: 1432-2307
    Keywords: Stomach ; Paraganglioma ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We report the second case of a malignant paraganglioma of the stomach in a 56-year-old female patient. However, our case is the first investigated by immunohistochemistry and electron-microscopy. The tumour was characterized immunohistochemically by the presence of neurofilament protein, glial fibrillary acidic protein, S-100 protein, neuron-specific enolase, chromogranin A, ACTH, leu-enkephalin and vasoactive intestinal polypeptide, and ultrastructurally by demonstration of neurosecretory granules and paranuclear intermediate filament whorls. Despite massive metastatic spread in the abdominal cavity, the patient is still alive 4 years after initial diagnosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01600143
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  • 5
    Electronic Resource
    Electronic Resource
    An electron microscopic study of glomerular lesions in hereditary nephrotic mice (ICGN strain) (1990)
    Springer
    Virchows Archiv 417 (1990), S. 223-228 
    Details
    ISSN: 1432-2307
    Keywords: Mouse ; Nephrotic syndrome ; Hereditary nephritis ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Glomerular lesions in hereditary nephrotic mice (ICGN strain) were investigated by electron microscopy. The glomeruli of unaffected animals, which appeared normal by light microscopy, had developed an ultrastructural change in the glomerular capillary basement membrane (GCBM). There was a partial thickening of the GCBM with bilaminar splitting of the lamina densa and an electron-dense fibrillar material exhibiting cross-striations. In affected animals, light microscopy revealed a marked thickening of GCBM and an increase of mesangial matrix without cellular proliferaton. By electron microscopy, multilaminar splitting of the lamina densa in the thickened GCBMs and fusion of the epithelial foot processes were observed. In some severely affected animals, immune complex deposition was found in GCBM, but little if any was observed in other animals. In the end, the glomeruli were globally sclerosed. Our findings suggest that initial structural abnormalities in GCBM may play an important role in the onset and development of the disease, though subsequent events such as immune complex deposition would modify the disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01600137
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  • 6
    Electronic Resource
    Electronic Resource
    Histological and ultrastructural effects of cyclosporin A on normal human skin xenografted on to nude mice (1990)
    Springer
    Virchows Archiv 416 (1990), S. 505-511 
    Details
    ISSN: 1432-2307
    Keywords: Cyclosporin A ; Human skin xenografts ; Histology ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cyclosporin A (CsA) is a potent immunosuppressant with a selective activity on T-helper lymphocytes. However, CsA also exerts biological effects on non-lymphoid cells (fibroblasts, endothelial and epithelial cells). CsA can inhibit in vivo and in vitro DNA synthesis of epidermal keratinocytes (EK) and induces in vivo morphological alterations of kidney epithelial cells. In the present study we investigated the in vivo effects of a short-term CsA treatment (50 mg/kg per day) on DNA synthesis (evaluated through 5-bromo-2′-deoxyuridine incorporation) and on the histological features of normal human skin xenografted (NHSX) on to congenitally athymic nude mice. When compared with control NHSX, CsA induced a statistically significant inhibition of DNA synthesis of NHSX EK. At the light- and electron-microscopic level, apart from a decrease in the thickness of the viable epidermis of NHSX (statistically non-significant), no noticeable differences between treated and control NHSX could be detected. EK, Langerhans cells and melanocytes appeared morphologically unaffected by CsA and no signs of acute toxicity (giant mitochondria, vacuolization, microcalcifications) were seen. These results suggest that CsA exerts a subtle effect on human EK; indeed, despite an unequivocal antiproliferative activity, no significant histological changes related to the acute CsA toxicity seem to be induced on the various epidermal cell types.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01600301
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  • 7
    Electronic Resource
    Electronic Resource
    Comparative histogenesis and morphogenesis of mucoepidermoid carcinoma and pleomorphic adenoma (1990)
    Springer
    Virchows Archiv 417 (1990), S. 405-417 
    Details
    ISSN: 1432-2307
    Keywords: Salivary gland ; Neoplasm ; Mucoepidermoid carcinoma ; Electron microscopy ; Histogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Current classifications of salivary gland tumors separate mucoepidermoid carcinoma from other neoplasms on the basis of a number of histological features, in particular the lack of participation of neoplastic myoepithelial cells. However, ultrastructural examination of low- and intermediate-grade mucoepidermoid carcinomas and pleomorphic adenomas reveals many common organizational and cellular features. Of prime importance is the relationship of intermediate cells to the luminal cells in mucoepidermoid carcinomas, which is remarkably similar to that seen between modified myoepithelial cells and luminal cells in pleomorphic adenomas. The results suggest that intermediate cells of mucoepidermoid carcinoma are the counterpart of the modified myoepithelial cells of pleomorphic adenoma. The generally accepted hypothesis that the former tumor develops from an excretory duct reserve cell, while the latter originates from an intercalated duct stem cell does not seem to be valid; pleomorphic adenoma and mucoepidermoid carcinoma appear to be closely related morphologically.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01606029
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  • 8
    Electronic Resource
    Electronic Resource
    Ultrastructural quantitation of atubular and hypertrophic glomeruli in rats with lithium-induced chronic nephropathy (1990)
    Springer
    Virchows Archiv 417 (1990), S. 513-522 
    Details
    ISSN: 1432-2307
    Keywords: Atubular glomeruli ; Chronic nephropathy ; Electron microscopy ; Lithium ; Stereology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The very heterogeneous population of glomeruli in rats with lithium-induced chronic nephropathy which includes small glomeruli without connection to a proximal tubule (atubular glomeruli) and large hypertropic glomeruli with connection to a normal proximal tubule, was studied at the ultrastructural level, using stereological methods. After 8 weeks of lithium treatment followed by 8 weeks without lithium the hypertrophic glomeruli showed no changes in their relative ultrastructural composition, including normal mesangium, basement membrane-like material and peripheral basement membrane. The absolute quantities of each component were, however, increased due to the increased volume of the glomeruli. The atubular glomeruli had increased volume fractions of mesangium, peripheral basement membrane, basement membrane-like material and epithelium, whereas the absolute quantities were decreased due to the decreased volume. The thickness of the basement membrane was within normal limits in the group of hypertrophic glomeruli but increased by 31% above controls in the group of atubular glomeruli. Both groups of glomeruli in lithium-treated animals showed normal mean foot process width, but with a slightly abnormal distribution. The atubular glomeruli showed a disproportionate large decrease in peripheral filtration surface and capillary length, compared with the reduction in glomerular volume, whereas the hypertrophic glomeruli showed changes in proportion with the increased volume.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01625732
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  • 9
    Electronic Resource
    Electronic Resource
    Neuropeptide Y- and substance P-like immunoreactive nerve fibers in the rat dura mater encephali (1990)
    Springer
    Anatomy and embryology 182 (1990), S. 363-373 
    Details
    ISSN: 1432-0568
    Keywords: Neuropeptide Y ; Substance P ; Immunocytochemistry ; C-fibers ; Dura mater ; Dural sinus ; Meningeal arteries ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Density and pattern of nerve fibers with neuropeptide Y-like immunoreactivity (NPY-LI) and substance P-like immunoreactivity (SP-LI) in the rat dura mater encephali were investigated by light and electron microscopy using whole-mount preparations. NPY-LI fibers are observed throughout the encephalic dura mater. A remarkable net of NPY-LI nerve fibers is located in the walls of the sagittal and transverse sinuses. Beyond that NPY-LI network, distinct NPY-LI nerve fibers or plexus occur in the rostral falx, parietal dura mater of the olfactory bulb, supratentorial dura mater, parietal dura mater of the cerebellum, tentorium cerebelli and the ventral dura mater. Electron microscopic studies reveal that NPY-LI is exclusively located in unmyelinated axons of small and large nerve fiber bundles, with or without a perineural sheath. Immunopositive C-fibers are predominantly associated with the vascular bed. SP-LI nerve fibers have a moderate and more uniform distribution in the encephalic dura mater. A distinct plexus of SP-LI fibers follows the branches of the middle meningeal artery and the adjacent dura mater. SP-LI fibers are most prominent in the parietal dura mater of the cerebellum. Fine beaded SP-LI fibers, arising from larger SP-LI fiber bundles, are observed in close association to the capillary bed. SP-LI axons are all unmyelinated. They are found in larger nerve fiber bundles with a perineural sheath or in Schwann cells lacking any perineural sheath. The function of NPY-LI and SP-LI nerve fibers in the rat dura mater is discussed in relation to their topography, density and termination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02433496
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  • 10
    Electronic Resource
    Electronic Resource
    Myopathy with altered mitochondria due to a triosephosphate isomerase (TPI) deficiency (1990)
    Springer
    Acta neuropathologica 79 (1990), S. 387-394 
    Details
    ISSN: 1432-0533
    Keywords: Triosephophosphate isomerase (TPI) ; Mitochondrial myopathy ; Muscle tissue ; Electron microscopy ; Enzyme histochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Morphological changes are shown in the muscle biopsy specimens of an 8-year-old girl who suffered from a triosephosphate isomerase (TPI) deficiency, resulting in a chronic, nonspherocytic, hemolytic anemia, mental retardation and neuromuscular impairment. The newly introduced enzyme histochemical reaction for TPI demonstrated a total lack of histochemically detectable enzyme activity, whereas biochemical analysis of muscle tissue revealed less than 10% of the normal enzyme activity. Electron microscopy showed a degenerative myopathy with an increase in the amount of intracellular glycogen. Additionally, mitochondrial changes within the muscle fibers were observed to be similar to those in mitochondrial myopathies. The disturbed balance between glycerinaldehyde phosphate and dihydroxy-acetone phosphate, due to the deficiency of the TPI enzyme, is interpreted as the biochemical background of an impaired electron transport across the mitochondrial membrane, resulting in the coexistence of an impaired glycolytic pathway and an impaired mitochondrial metabolism of muscle cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00308714
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  • 11
    Electronic Resource
    Electronic Resource
    Myopathy in Marinesco-Sjögren syndrome: an ultrastructural study (1990)
    Springer
    Acta neuropathologica 80 (1990), S. 123-128 
    Details
    ISSN: 1432-0533
    Keywords: Marinesco-Sjögren syndrome ; Muscle biopsy ; Electron microscopy ; Autophagocytosis ; Double-membrane structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Seven muscle biopsies from patients with the clinical characteristics of Marinesco-Sjögren syndrome (MSS) revealed myopathic changes of two types; muscle fiber necrosis followed by regeneration and focal myofibrillar degeneration inducing autophagocytosis with rimmed vacuole formation. In two young patients, massive muscle fiber necrosis with phagocytic invasion was the predominant feature and autophagic phenomenon was minimal, resembling the findings in progressive muscular dystrophy. Myofibrillar degeneration with autophagic phenomenon was prominent in five adult patients. The coexistence of these two degenerative processes and the secondarily induced reactive changes of muscle fiber hypertrophy, interstitial fibrosis, occasional ragged-red fibers and type 1 fiber predominance, are responsible for the wide spectrum of muscle pathology in MSS. The dense double-membrane structure surrounding myonuclei, previously reported as being specific to MSS, was present in only one biopsy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00308914
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  • 12
    Electronic Resource
    Electronic Resource
    Histological changes of neuronal damage in vegetative dogs induced by 18 minutes of complete global brain ischemia: two-phase damage of Purkinje cells and hippocampal CA1 pyramidal cells (1990)
    Springer
    Acta neuropathologica 80 (1990), S. 527-534 
    Details
    ISSN: 1432-0533
    Keywords: Global ischemia ; Cerebellum ; Hippocampus ; Electron microscopy ; Synapse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have developed a functional vegetative model by an 18-min clamping of the ascending aorta combined with a bypass formation between the aorta to right atrium and the aorta to femoral vein. Complete global brain ischemia (CGBI) induced for 18 min with this model provided the following distinct advantages: cardiopulmonary functions were well preserved during postischemic recirculation, and all dogs survived without serious extracerebral complications. Neuronal damage in vegetative dog induced by an 18-min CGBI was studied by light and electron microscopy. The Purkinje cells and the hippocampal CA1 pyramidal cells showing clumping of nuclear chromatin and slightly increased stainability were observed after CGBI without recirculation. All these neurons showed transient increased stainability with microvacuolation 15 min after recirculation. Over 50% of these neurons showed virtually normal features 1 h after recirculation. Damage to these neurons progressed again slowly up to 6 h after recirculation. However, all these neurons had disintegrated 2–3 days after recirculation. A decrease in synaptic vesicles was observed in many presynaptic terminals in the molecular layers of the cerebellum after CGBI without recirculation. These changes in the presynaptic terminals progressed 15 min after recirculation. These results indicated that the damage to the Purkinje cells and the CA1 pyramidal cells induced by CGBI consisted of two phases, and that the change in the early phase was reversible. We speculate that the damage to the Purkinje cells in the early stage is related to the decrease of the synaptic vesicles in the presynaptic terminals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294614
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  • 13
    Electronic Resource
    Electronic Resource
    An immunocytochemical study of protein clearance in brain infusion edema (1990)
    Springer
    Acta neuropathologica 81 (1990), S. 162-177 
    Details
    ISSN: 1432-0533
    Keywords: Infusion edema ; Immunocytochemistry ; Clearance ; Electron microscopy ; Brain edema
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The pathways and mechanisms by which edematous fluid accumulation in the extracellular space (ECS) clears from brain are poorly understood. The objective of this study was to explore, using immunocytochemical technique, the fate of a proteinaceous fluid added to the brain ECS and to study the clearance pathways. The protein movement of this edema fluid was investigated using the direct infusion model on rats. Rat albumin (20 μl) was slowly infused into the caudate-putamen of anesthetized adult rats and the spread and clearance of the edema was followed in various brain regions using immunocytochemical and conventional light and electron microscopy at 0, 1, 2, 3, 4, 6, and 8 days post-infusion. Our studies showed that protein-rich edema fluid cleared slowly from the brain, with 8 days required for the infusion albumin to exit completely from the brain parenchyma. Immediately following infusion, the albumin was distributed in the ECS of the white matter and the overlying deep cortical layers related to the infusion site. During the next 24 h, more of the infused albumin traveled through the ECS to the cortical surface where the albumin passed through the glia limitans to reach the subarachnoid front. Additionally, at 48 h post-infusion, that albumin, which had migrated to the ventricular wall, cleared from the ECS of the subependymal white matter and the ependymal clefts to reach the ventricular cerebrospinal fluid (CSF). In edematous regions, the perivascular spaces of venules and veins were filled with reaction product. Continuity of this perivascular reaction product existed from the deep edematous area to the temporobasal subarachnoid space from where the reaction product gradually disappeared from the parenchyma. From these studies we infer that during the late state of the resolution process the edema front moves toward both the ventricle and the cortical surface to reach the CSF. Thus, among the potential routes for edema clearance, the pathways leading to CSF clearance of fluid predominated. During this clearance process, neither neurons, glia nor the vascular endothelium showed any endocytotic response to the infused albumin throughout the 8-day course. We conclude from these observations that the CSF pathway is the major route of protein-rich edema clearance, when such clearance is not complicated by any concomitant CNS perturbation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334505
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  • 14
    Electronic Resource
    Electronic Resource
    An immunoelectron microscopic study of corticotrophs in the golden hamster (1990)
    Springer
    Anatomy and embryology 182 (1990), S. 539-545 
    Details
    ISSN: 1432-0568
    Keywords: Corticotrophs ; Pituitary gland ; Golden hamster ; Immunocytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of corticotrophs in the pituitary of golden hamsters was studied by immunocytochemistry. Corticotrophs were classified into three types according to the different size of the secretory granules. Type A and B cells were oval or polygonal in shape containing small (158±38 nm) and medium-sized (250±53 nm) secretory granules, respectively. Type C cells were usually pyramidal or irregular in shape, and contained large secretory granules (380±78 nm). The cytoplasmic organelles of type B and C cells were fairly well developed. In all types of corticotrophs, the secretory granules varied in electron density, and were either arranged in a single row along the cell membrane, or concentrated in the vascular pole of the cytoplasm. Many of the corticotrophs sent processes to encircle neighboring somatotrophs. In the female, the proportions of type A and B cells were higher then those in the male, whereas that of the type C cells was lower. All three types of corticotrophs were observed in the early postnatal stage. The population of type A cells decreased with the advancement of postnatal development, with a concomitant increase of that of the type C cells. Thus, type A cells might represent the immature type of corticotrophs which would evolve to become the type C cells. One to 2 weeks after adrenalectomy, the number of type C cells was drastically increased. This was accompanied by their prominent changes in ultrastructure as in the type B cells. The cytoplasm became hypertrophic with extensive dilated cisternae of rough endoplasmic reticulum. The large Golgi apparatus displayed profiles seemingly involved in the formation of secretory granules. The number of type A cells was moderately decreased, and they showed little morphological alteration. Since type B and C corticotrophs exhibited a remarkable response to adrenalectomy, it is concluded that they represent the active state of corticotrophs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00186460
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  • 15
    Electronic Resource
    Electronic Resource
    Patterns of differentiation in central neurocytoma (1990)
    Springer
    Acta neuropathologica 79 (1990), S. 473-479 
    Details
    ISSN: 1432-0533
    Keywords: Central neurocytoma ; Neuronal differentiation ; Glial differentiation ; Synaptophysin ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Central neurocytoma has been characterised by its intraventricular localisation, predominant occurrence in young adults, oligodendroglioma-like histology, benign course and ultrastructural evidence for neuronal differentiation. Eleven intraventricular central neurocytomas were studied histopathologically, employing cell type-specific immunocytochemical markers and electron microscopic analysis. In the past, these lesions have caused diagnostic problems since central neurocytomas share basic histopathological features with other periventricular neoplasms. Accordingly, several tumours of this series had previously been classified as ependymomas of the foramen of Monro or oligodendrogliomas. Although generally regarded as benign lesions, two central neurocytomas of this series showed histopathological evidence of anaplasia, with focal necrosis, mitotic activity and vascular proliferation. All central neurocytomas exhibited immunoreactivity for neuronspecific enolase and synaptophysin, indicating consistent neuronal differentiation. Three tumours were studied by electron microscopy and contained synaptic vesicles, neuritic processes and neurosecretory granules. In addition, one tumour contained ganglioid cells and this was associated with focal immunoreactivity for neurofilament protein, suggesting that some central neurocytomas may, at least focally, continue to differentiate towards the formation of mature neurons. Two of the tumours expressed glial fibrillary acidic protein in a considerable percentage of neoplastic cells which demonstrates a capacity for bipotential, i.e. glial and neuronal differentiation. We conclude that the central neurocytoma can be reliably diagnosed using antibodies to neuron-specific enolase and synaptophysin, and that histogenetically, this neoplasm is derived from a neuroectodermal precursor cell capable of both, neuronal and glial differentiation. The hypothesis is proposed that the central neurocytoma originates from the subependymal plate of the lateral ventricles, an embryonal matrix cell layer which postnatally maintains a limited proliferative potential.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296105
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  • 16
    Electronic Resource
    Electronic Resource
    Polar spongioblastoma: an immunohistochemical and electron microscopical study (1990)
    Springer
    Acta neuropathologica 81 (1990), S. 228-232 
    Details
    ISSN: 1432-0533
    Keywords: Cerebral tumor ; Polar spongioblastoma ; Astrocytoma ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case is reported of a 9-year-old boy with a cerebral polar spongioblastoma. This neoplasm, first described by Russell and Cairns in 1947, is morphologically a distinct entity characterized by bipolar tumor cells with palisading nuclei. In the case under study immunoreactivity for neuron-specific enolase was found and ultrastructural features of developing neuronal elements were present. A neuro-endocrine nature was suggested by de Chadarévian et al. (1984) in a morphologically similar case. These findings are in contrast with the longheld view that the polar spongioblastoma is cytogenetically related to the embryonal radial glial cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334514
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  • 17
    Electronic Resource
    Electronic Resource
    Appearance of tubulovesicular structures in experimental Creutzfeldt-Jakob disease and scrapie preceeds the onset of clinical disease (1990)
    Springer
    Acta neuropathologica 79 (1990), S. 349-354 
    Details
    ISSN: 1432-0533
    Keywords: Creutzfeldt-Jakob disease ; Electron microscopy ; Scrapie ; Tubulovesicular structures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have consistently observed tubulovesicular structures in brain tissues during the terminal stages of naturally occurring and experimentally induced spongiform encephalopathies, irrespective of the host species and virus strain. In NIH Swiss mice inoculated intracerebrally or intraocularly with the Fujisaki strain of Creutzfeldt-Jakob disease (CJD) virus, tubulovesicular structures, measuring 20–50 nm in diameter, were particularly prominent in dilated, pre-and postsynaptic neuronal processes, occasionally being mixed with synaptic vesicles. These structures appeared 13 weeks following intracerebral inoculation, 5 weeks before the onset of clinical signs, when spongiform changes were also detected. The number and density of tubulovesicular structures increased steadily during the course of clinical disease, and were particularly abundant in mice 47 to 51 weeks after intraocular inoculation. In hamsters infected with the 263 K strain of scrapie virus, these structures were initially detected 3 weeks following intracerebral inoculation and increased dramatically at 10 weeks postinoculation. The appearance of tubulovesicular structures before the onset of overt disease in mice inoculated with CJD virus by either the intracerebral or intraocular route, and before the appearance of other neuropathological changes in hamsters infected with scrapie virus, indicate that they represent either a part or aggregate of the infectious virus or a pathological product of the infection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00308710
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  • 18
    Electronic Resource
    Electronic Resource
    Ultrastructural and biochemical findings in brain cell cultures infected with canine distemper virus (1990)
    Springer
    Acta neuropathologica 80 (1990), S. 59-67 
    Details
    ISSN: 1432-0533
    Keywords: Brain cell culture ; Canine distemper virus ; Cerebroside sulfotransferase ; Electron microscopy ; Oligodendrocytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To study the pathomechanism of demyelination in canine distemper (CD), dog brain cell cultures were infected with virulent A75/17-CD virus (CDV) and examined ultrastructurally. Special attention was paid to the oligodendrocytes, which were specifically immunolabelled. In addition, cerebroside sulfotransferase (CST), an enzyme specific for oligodendrocyte activity was assayed during the course of the infection. Infection and maturation as well as CDV-induced changes were found in astrocytes and brain macrophages. Infection of oligodendrocytes was rarely seen, although CST activity of the culture markedly decreased and vacuolar degeneration of these cells occurred, resulting in their complete disappearance. We concluded that the degeneration of oligodendrocytes and demyelination is not due to direct virus-oligodendrocyte interaction, but due to CDV-induced events in other glial cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294222
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  • 19
    Electronic Resource
    Electronic Resource
    A case of cerebral composite ganglioneuroblastoma: an immunohistochemical and ultrastructural study (1990)
    Springer
    Acta neuropathologica 80 (1990), S. 98-102 
    Details
    ISSN: 1432-0533
    Keywords: Composite ganglioneuroblastoma ; Electron microscopy ; Cerebrum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An unusual cerebral tumor is reported in a 14-year-old boy. On light and electron microscopy, the constituent cells were very complex; the majority of the neoplastic cells were primitive neuroectodermal cells dispersed in myxomatous or fibrous stroma. Neoplastic neuronal cells and hypertrophic astrocytes were also observed in these areas. The neuronal cells showed a continuous spectrum of differentiation from very primitive to mature ganglion cells. Furthermore, the tumor contained a highly cellular discrete area consisting of neuroblasts and their precursor cells. From these findings, a diagnosis of composite ganglioneuroblastoma was made.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294230
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  • 20
    Electronic Resource
    Electronic Resource
    Cerebral medulloepithelioma — electron microscopy and immunohistochemistry (1990)
    Springer
    Acta neuropathologica 80 (1990), S. 103-107 
    Details
    ISSN: 1432-0533
    Keywords: Brain neoplasms ; Medulloepithelioma ; Primitive neuro-ectodermal tumor ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case is reported of a boy, 3 years of age, with a large medulloepithelioma in the left cerebral hemisphere. Medulloepitheliomas are rare tumors of the primitive medullar epithelium. Histological, immunohistochemical and electron microscopical findings are presented. We discuss previously reported cases, the ontogeny of this type of tumor and the relation to the socalled primitive neuro-ectodermal tumors (PNET).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294231
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  • 21
    Electronic Resource
    Electronic Resource
    An autopsy case of peroneal muscular atrophy with rigidity and tremor (1990)
    Springer
    Acta neuropathologica 80 (1990), S. 671-679 
    Details
    ISSN: 1432-0533
    Keywords: Peroneal muscular atrophy ; Rigidity and tremor ; Autopsy ; Morphometry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An autopsy case of hereditary peroneal muscular atrophy (PMA) with rigidity and static tremor is presented. The patient developed slowly progressive distal muscular atrophy of the legs at the age of 15 years. By the age of 52 years, PMA became marked associated with pes cavus, and tremor and rigidity of the extremities were noted. Motor and sensory conduction velocities gradually depressed and lost near the end of his life. At autopsy, the major neuropathological abnormalities involved the peripheral nervous systems, and were characterized by axonal atrophy and loss of myelinated fibres. These changes involved both the proximal and distal nerves, being more severely affected in the distal. The pathological changes in other regions of the nervous systems were mainly confined to the spinal cord, dorsal ganglia and spinal nerve roots, and pigmented neurons in the brain stem. Morphometrically, the total fascicular area was much smaller than in control, but the total number of myelinated fibers greatly outnumbered that of control 75 200 to 48 200 at the proximal sciatic nerve and then gradually decreased towards the periphery; however, even in the distal sural nerve, the total number of myelinated fibers exceeded that of control (6820 to 5469). Thus, the density of myelinated fibers were much higher, being 1.5 to 2 times greater, than in control. Its abrupt decline at the distal nerve might account for neurogenic atrophy of the distal musculature. Unmyelinated fibers were slightly increased in density and not atrophic. This case is unique in its clinicopathology and does not belong to any subtypes of PMA including “neuronal plus”.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307638
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  • 22
    Electronic Resource
    Electronic Resource
    Demyelination and remyelination in spinal cord lesions of human lymphotropic virus type I-associated myelopathy (1990)
    Springer
    Acta neuropathologica 81 (1990), S. 78-83 
    Details
    ISSN: 1432-0533
    Keywords: HTLV-I-associated myelopathy ; Spinal cord lesion ; Electron microscopy ; Primary demyelination ; Remyelination by oligodendrocytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We describe postmortem findings in a patient with human T lymphotropic virus type I (HTLV-I)-as-sociated myelopathy (HAM). The patient developed the disease 8 years after blood transfusion and showed good response to corticosteroid treatment but died of cardiac failure. Histologically, chronic, mild meningoence-phalomyelitis was noted predominantly involving the bilateral lateral and anterior columns of the middle to lower thoracic segments. The spinal cord lesions showed obvious loss of myelinated nerve fibers and fibrillary gliosis with minimal inflammatory cell infiltration. Electron microscopy of the lesion revealed disintegration of the myelin sheaths, regular separation of the minor dense line of the myelin sheaths, and completely demyelinated axons. In addition, remyelinated fibers with thin central myelin sheaths and disproportionately large axons were seen frequently. These findings indicate that primary demyelination and remyelination by oligodendrocytes occur in the spinal cord lesions of HAM.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00662641
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  • 23
    Electronic Resource
    Electronic Resource
    Ultrastructure, protein synthesis and secretion of day-6 rabbit blastocysts cultured in a chemically defined, protein-free medium (1990)
    Springer
    Anatomy and embryology 182 (1990), S. 465-472 
    Details
    ISSN: 1432-0568
    Keywords: In vitro culture ; Electron microscopy ; Fluorography ; Blastocyst ; Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Day-6 rabbit blastocysts were cultured in Ham's F10 medium supplemented with polyvinylpyrrolidone as a macromolecular component, for 4 to 12 h. The integrity of the blastocyst cells was demonstrated by electron microscopy. Expansion and biosynthesis of proteins and of DNA were studied after culturing in the presence of 35S-methionine and 3H-thymidine. Polyvinylpyrrolidone did not interfere with the subsequent protein analysis, which was performed by two dimensional gel electrophoresis followed by silver staining and fluorography. More than 600 labelled proteins were found in the blastocyst tissue, many of them were also present in the blastocyst fluid and in the blastocyst coverings. Several proteins seemed to be produced for incorporation into the blastocyst coverings; others, only detected in the culture medium, might have been synthesized for secretion into the environment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00178911
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  • 24
    Electronic Resource
    Electronic Resource
    Immunocytochemical localization of CR3 complement receptors with OX-42 in amoeboid microglia in postnatal rats (1990)
    Springer
    Anatomy and embryology 182 (1990), S. 481-486 
    Details
    ISSN: 1432-0568
    Keywords: Immunocytochemistry ; Electron microscopy ; CR3 receptors ; Amoeboid microglia ; Rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The present study described the labelling of amoeboid microglial cells in the postnatal rat brain with OX-42, an antibody that recognizes type 3 complement receptors CR3 in mononuclear phagocytes. Of the diverse morphological forms of amoeboid microglia present in the corpus callosum in early postnatal (2–5 days) rats, cells with a round regular outline, or showing short stout processes, were the most intensely stained. When traced from the main cell colony into the borderline zone with the cortex, the immunoreactivity of amoeboid microglia that assumed a ramified form was drastically reduced. Examination of materials from the late postnatal (8–12 days) age group showed that the majority of the OX-42 positive cells in the corpus callosum became oval, elongated and ramified. Immunoelectron microscopy confirmed the above observations, and also showed that the immunoreactivity in the round amoeboid microglia was localized in their plasma membrane, surface projections and invaginations, as well as in some of the subsurface vacuoles. The immunoreactivity was reduced in the oval cells, and diminished in the elongated or ramified form. It is proposed that the presence of CR3 membrane receptors in amoeboid microglial cells is related to their active role in endocytosis. These, however, diminish with the growth of the brain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00178913
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  • 25
    Electronic Resource
    Electronic Resource
    Distribution and characteristics of the different astroglial cell types in the adult lizard (Lacerta lepida) spinal cord (1990)
    Springer
    Anatomy and embryology 181 (1990), S. 567-575 
    Details
    ISSN: 1432-0568
    Keywords: Astrocyte ; Radial astrocyte ; GFAP ; Electron microscopy ; Phylogeny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The astroglial cells have been studied in the lizard spinal cord by means of metallic impregnations, immunohistochemical (glial fibrillary acidic protein) and ultrastructural methods. Three astroglial cell types have been immunohistochemically identified: ependymocytes, radial astrocytes and astrocytes. Transitional forms have also been observed. Scarce immunopositive ependymocytes were located in the dorsal and ventral regions of the ependyma. The radial astrocytic somata were located around the ependymal layer and their processes reached the subpial glia limitans. Typical astrocytes were the most abundant astroglial cell type; astrocytes located in the ventral horn showed a greater development than those of the dorsal horn. In the white matter, the astrocytes were large and their processes formed part of the subpial glia limitans; on some occasions, astrocytic cell bodies also formed part of this subpial limitans. Transitional elements between astrocytes and radial astrocytes were observed in both grey and white matter. The perivascular and subpial glia limitans were continuous and showed a strong immunoreactivity. The comparative analysis of our results in the lizard spinal cord with those in other vertebrate groups leads us to conclude that reptiles could represent the key group in the phylogenetic evolution of the astroglial cells in vertebrates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00174628
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  • 26
    Electronic Resource
    Electronic Resource
    Hereditary palmoplantar keratosis of the Gamborg Nielsen type (1990)
    Springer
    Archives of dermatological research 282 (1990), S. 363-370 
    Details
    ISSN: 1432-069X
    Keywords: Autosomal recessive palmoplantar keratosis ; Electron microscopy ; Keratinization ; Keratohyalin ; Keratohyaline proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A new kind of diffuse palmoplantar keratoderma with autosomal recessive inheritance and without associated symptoms was described in Norrbotten, Sweden by Gamborg Nielsen in 1985. Clinically, it ranges between the less severe dominant Unna-Thost type and the more severe recessive Meleda type, as it is milder than the latter. Skin biopsies of five patients from three different families with this new palmoplantar keratoderma, as well as five obligatory heterozygotes from one family, were investigated ultrastructurally in order to characterize this new entity and to differentiate it from the Meleda type. Several features are common to both autosomal recessive palmoplantar keratoses. They show a broadened granular layer, a transit region consisting of cells with a marginal envelope, and considerable hyperkeratosis. Morphologically, this transformation delay is less pronounced in the Gamborg Nielsen type than in the classical Meleda type. As is typical for ridged skin, both types of palmoplantar keratoses possess composite keratohyaline granules. In contrast to the normal appearance of keratohyaline granules in the Meleda type, the Gamborg Nielsen type also shows qualitative deviations of keratohyaline granules with different degrees of spongiosity and electron density and sometimes with a granular border. It seems that abnormal keratohyaline proteins are synthesized that behave differently. The sudden transformation of a granular into a horny cell is physiologically regulated by different enzymes. A delay in this process may be caused by a mutation that reduces or alters the enzymes concerned. We assume the palmoplantar keratoderma of the Gamborg Nielsen type to be a variant of the heterogeneous group of the Meleda type of palmoplantar keratoderma with autosomal recessive inheritance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00372085
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  • 27
    Electronic Resource
    Electronic Resource
    Electron microscopic study of cultured cells from the murine hair tissues: cell growth and differentiation (1990)
    Springer
    Archives of dermatological research 282 (1990), S. 402-407 
    Details
    ISSN: 1432-069X
    Keywords: Electron microscopy ; Culture ; Hair cells ; Growth ; Differentiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The cultured hair cells from 4-day-old C3H mice were studied by electron microscopy. The hair roots isolated from the skin by collagenase digestion were dispersed into a cell suspension by treatment with a mixture of trypsin and ethylenediaminetetraacetate. The cells were cultured in MCDB-153 (a medium containing seven growth factors) for 1, 3, 6 or 13 days. The number of cultured cells on day 3 was twice that on day 1, and stayed at the same level until day 13. By electron microscopy, some of the cells cultured for 1 day were seen to be undifferentiated and others already showed differentiation into various hair structures. Such differentiated cells disappeared on day 3 and most of the cells cultured for 3 days were undifferentiated. Cells cultured for 6 days were differentiated showing inner root sheath cell, hair cortical cell and medulla cell structures. The characteristics of these cultured cells corresponded well to those of in vivo cells of the hair tissues from the back skin of 7-day-old C3H mice. On day 13 degeneration occurred in the cultured cells. In none of these cultures were mesenchymal cells, such as fibroblasts, found. The present electron microscopic study reveals that immature cells obtained from mouse hair tissues proliferate in vitro and differentiate into several subpopulations corresponding to those of in vivo cell layers of hair tissues. The present culture technique may be useful for studies of hair cell growth and differentiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00372092
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  • 28
    Electronic Resource
    Electronic Resource
    Ultrastructural localization of keratin and α-l-fucose in human eccrine sweat glands (1990)
    Springer
    Archives of dermatological research 282 (1990), S. 12-16 
    Details
    ISSN: 1432-069X
    Keywords: Immunogold ; Electron microscopy ; Eccrine sweat glands ; Keratin ; Fucose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Human eccrine sweat glands were embedded in Lowicryl K4M. Cytokeratin proteins and blood group H antigen were localized by applying a postembedding immunogold method using a monoclonal antikeratin antibody and the lectin Ulex europaeus I. The antikeratin antibody labeled intermediate filaments in the secretory coil and dermal duct. Within dark secretory cells bundles of filaments criss-crossing the cell were labeled. Within the luminal cells of the dermal duct filaments arranged parallel to the cell surface and lying in the apex of the cell were labeled, too. The association of keratin filaments with desmosomes was visualized demonstrating their subcellular connection with other cell organelles. The desmosomes themselves remained unlabeled. The lectin Ulex europaeus I is a blood group H specific lectin and binds to α-l-fucosyl-containing glycoproteins. Dark cells of the secretory coil reacted with the lectin. Here the secretory granules, the lateral cell membranes, and the microvilli membranes were labeled. The endoplasmatic reticulum, the Golgi complex, and transport vesicles were not labeled, although the glycoprotein synthesis is considered to be located in the Golgi complex. Thus, either the number of α-l-fucose molecules in the Golgi is too low to be detected by the technique employed or the determinant of blood group H antigen is released after the secretory granules and transport vesicles leave the Golgi complex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00505639
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  • 29
    Electronic Resource
    Electronic Resource
    Bicomponent keratohyalin in normal human ridged skin (1990)
    Springer
    Archives of dermatological research 282 (1990), S. 71-75 
    Details
    ISSN: 1432-069X
    Keywords: Bicomponent keratohyalin ; Ridged skin ; Keratinization ; Sweat ducts ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Up to now, bicomponent keratohyalin has only been described for rat epithelium and human intraepidermal sweat ducts and fetal nail organ cells. In normal human interductal epidermis, the keratohyalin appears homogeneous, osmiophilic and stellate in shape. Under pathological conditions, bicomponent keratohyalin has been observed in different palmoplantar keratoses and has therefore been thought to be associated with abnormal keratosis. We studied the keratinization process in normal human plantar epidermis, in which keratohyalin was found to exhibit several morphological differences as compared to that seen in non-ridged skin. The most striking feature was seen in upper granular cells, where the keratohyalin granules consisted of two components of differing electron density. The electron-dense component formed the main part of the composite granule and was found in the cytoplasm of lower and upper granular cells. The less-electron-dense component was attached to the main component and appeared in the cytoplasm of upper granular cells, forming the convex contact zone. No intranuclear osmiophilic inclusions were present. The respective electron densities of the two keratohyalin components of ridged skin were obviously different to that of the bicomponent keratohyalin granules seen in the epidermal sweat-duct cells of the same specimen. These findings indicate the presence of at least two different types of keratohyalin proteins in normal human ridged skin. They can be distinguished at the electron-microscope level and differ from the keratohyalin of human non-ridged skin as well as from bicomponent keratohyalin granules derived from human epidermal sweat-duct cells or from rat epithelium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00493461
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  • 30
    Electronic Resource
    Electronic Resource
    Altered keratin expression in ichthyosis hystrix Curth-Macklin (1990)
    Springer
    Archives of dermatological research 282 (1990), S. 227-233 
    Details
    ISSN: 1432-069X
    Keywords: Genodermatoses ; Keratinization disorders ; Fetal cytokeratins ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The pathogenesis of a rare form of the ichthyotic diseases, ichthyosis hystrix Curth-Macklin, was investigated by immunohistochemistry and electron microscopy. Monoclonal antibodies (Mabs) against keratins expressed in normal basal cells (PKK2 and KA1), Mabs against keratins only present in normal fetal skin (PKK1), and Mabs against keratins 1, 2, 10, and 11 (KA5 and K8.60) were used. The Mabs reacting with normal basal cells showed an increased reaction with many cell layers. The Mab PKK1 distinctly reacted with the basal cell layer, suggesting an expression of fetal keratins. Electron microscopic study of both normal-looking and involved skin revealed the keratinization disorder characterized by tonofilament shells, perinuclear vacuoles, and binuclear keratinocytes. The results suggest that there is no prematurity of keratinization, but rather a pathological expression of specific keratin genes leading to expression of fetal keratins in this form of ichthyosis hystrix.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00371641
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  • 31
    Electronic Resource
    Electronic Resource
    Electron microscopy: A contribution to further classification of acute unclassifiable childhood leukemia (1990)
    Springer
    Annals of hematology 60 (1990), S. 291-296 
    Details
    ISSN: 1432-0584
    Keywords: Electron microscopy ; Leukemia ; Minimally differentiated leukemia ; Childhood
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructural, light microscopical and immunological features of twelve cases of acute childhood leukemia are described. Nine cases were unclassifiable by light microscopy, morphology and cytochemistry, and three were difficult to classify because of a low percentage of Sudan-Black B positive blasts. By means of electron microscopy (including peroxidase cytochemistry), two main groups were seen: 1. Acute myeloid leukemia, in which could be distinguished a) a more differentiated myeloid leukemia, b) a leukemia with megakaryoblastic involvement and c) a minimally differentiated acute myeloid leukemia with granules present and 2. lymphoblastic leukemia. One case could not be classified. The first group included two possible cases of a hybrid leukemia with CD19 or CD10 positivity as well as ultrastructural peroxidase activity. We conclude that electron microscopy aids to further classification of minimally differentiated and hybrid acute leukemias.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01736231
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  • 32
    Electronic Resource
    Electronic Resource
    Catecholamine-containing axon terminals in the hypoglossal nucleus of the rat: an immuno-electronmicroscopic study (1990)
    Springer
    Experimental brain research 81 (1990), S. 167-178 
    Details
    ISSN: 1432-1106
    Keywords: Hypoglossal nucleus ; Catecholamines ; Norepinephrine ; Immunocytochemistry ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A correlative light and electron microscopic investigation was undertaken to determine the morphology and distribution of catecholamine (CA)-containing axon terminals in the hypoglossal nucleus (XII) of the rat. This was accomplished immunocytochemically with antibody to tyrosine hydroxylase (TH). The major findings in this study were the following: 1) Immunoreactive profiles were found throughout XII and included unmyelinated axons, varicosities, axon terminals and dendrites; 2) Nonsynaptic immunoreactive profiles (preterminal axons, varicosities) were more frequently observed (55.2%) than synaptic profiles (43.5%); 3) CA-containing axon terminals ending on dendrites were more numerous (71.8%) than those synapsing on somata (25.4%) or nonlabeled axon terminals (2.7%); 4) The morphology of labeled axon terminals was variable. Axodendritic terminals typically contained numerous small, round agranular vesicles, a few large dense-core vesicles and were associated with either a symmetric or no synaptic specialization, axosomatic terminals were often associated with a presynaptic membrane thickening or a symmetric synaptic specialization and contained small, round and a few elliptical-shaped vesicles, while axoaxonic synapses formed asymmetric postsynaptic specializations; and 5) CA-positive dendritic processes were identified in XII. These findings confirm the CA innervation of XII, and suggest a complex, multifunctional role for CA in controlling oro-lingual motor behavior.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00230113
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  • 33
    Electronic Resource
    Electronic Resource
    Renal amyloidosis in juvenile chronic arthritis: evolution after chlorambucil treatment (1990)
    Springer
    Pediatric nephrology 4 (1990), S. 463-469 
    Details
    ISSN: 1432-198X
    Keywords: Juvenile chronic arthritis ; Renal amyloidosis ; Chlorambucil ; Electron microscopy ; Protein AA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Over a 22-year period, eith patients affected with severe systemic or polyarticular juvenile chronic arthritis (JCA) developed systemic amyloidosis with nephrotic syndrome. They were treated with chlorambucil over 5–192 months (mean=44 months). With treatment, an abrupt decrease in the severity of JCA was observed in six patients but two patients were chlorambucil resistant. After a mean follow-up period of 10 years from onset of renal symptoms, one chlorambucil-resistant patient died of end-stage renal failure; two patients have a persistent nephrotic syndrome; and five patients are free from proteinaria, of whom one has developed hypertension. A good correlation was observed between the response of the rheumatic disease to chlorambucil treatment and the clinical course of renal symptoms. Fourteen renal biopsies were performed in these eight patients. In all, amyloid deposits were of the AA type, which persisted on repeat biopsies. In addition, 15%–60% of glomeruli had become globally sclerotic by the second or third biopsies. At the ultrastructural level, modifications in the structure of amyloid deposits and reparative changes of the glomeruli, characterized by partial restoration of glomerular architecture, were observed in three patients with a favourable clinical course.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00869821
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  • 34
    Electronic Resource
    Electronic Resource
    Medium-chain acyl CoA dehydrogenase deficiency: Electron microscopic differentiation from Reye syndrome (1990)
    Springer
    European journal of pediatrics 150 (1990), S. 111-114 
    Details
    ISSN: 1432-1076
    Keywords: Electron microscopy ; Liver ; MCAD deficiency ; Reye syndrome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Inborn errors involving the oxidative metabolism of fatty acids may present clinically with a Reye syndrome-like picture. This case report of a patient with medium-chain acyl CoA dehydrogenase (MCAD) deficiency illustrates that electron microscopy may help to differentiate this disorder from Reye syndrome even if a liver biopsy is performed in a patient who recovered from an acute metabolic decompensation. Together with this case, a review of the few reports in the literature of pathological findings in MCAD deficiency is given. Changes uncharacteristic for Reye syndrome are a largedroplet steatosis and the presence of distinctive mitochondrial abnormalities on electron microscopy. The detection of an electron dense mitochondrial matrix and a widened space of inner mitochondrial membranes rules out Reye syndrome and is suggestive of a disorder of mitochondrial fatty acid oxidation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02072051
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  • 35
    Electronic Resource
    Electronic Resource
    Loss of nerve fibres in the corpus callosum of progressive subcortical vascular encephalopathy (1990)
    Springer
    Journal of neurology 237 (1990), S. 39-41 
    Details
    ISSN: 1432-1459
    Keywords: Progressive subcortical vascular encephalopathy ; Electron microscopy ; Nerve fibres ; Corpus callosum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The nerve fibres of the corpus callosum were studied by electron microscopy in five elderly patients with progressive subcortical vascular encephalopathy (PSVE) and compared with those in six age-matched controls. The number of nerve fibres per unit area of the corpus callosum was decreased in PSVE by 18–26%. The loss of nerve fibres in the corpus callosum can play a role in inducing the cognitive deficit of PSVE, on the basis of the loss of nerve fibres in the cerebral hemispheres.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00319666
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  • 36
    Electronic Resource
    Electronic Resource
    Light and electron microscopic examination of amyloid-rich primitive plaques: comparison with diffuse plaques (1990)
    Springer
    Journal of neurology 237 (1990), S. 88-93 
    Details
    ISSN: 1432-1459
    Keywords: Amyloid-rich primitive plaque ; Diffuse plaque ; Amyloid ; Periodic-acid methenamine silver method ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In Alzheimer-type dementia brains, numerous “amyloid-rich primitive plaques (PPs)” were observed with β-protein immunostaining and periodicacid methenamine (PAM) staining. These amyloid-rich primitive plaques were accompanied by various degrees of small argyrophilic rod-like, granular or filamentous structures. Routine and modified-PAM electron microscopy revealed many bundles and flecks consisting of amyloid fibrils scattered widely throughout the plaques. Degenerate neurites, astrocytic processes and bundles of glial fibres also participated in the formation of the plaques. The similarities and differences between these amyloid-rich primitive plaques and diffuse plaques are described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00314668
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  • 37
    Electronic Resource
    Electronic Resource
    Primary intracerebral sarcoma in childhood: case report with electron-microscope study (1990)
    Springer
    Journal of neurology 237 (1990), S. 382-384 
    Details
    ISSN: 1432-1459
    Keywords: Intracerebral sarcoma ; Meningeal sarcoma ; Light microscopy ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case of a primary intracerebral sarcoma is described in a 5-year-old girl. Histology and immunohistochemistry excluded the diagnosis of a leiomyosarcoma, a malignant haemangiopericytoma or a fibrosarcoma; electron-microscopical findings indicated that the origin of the sarcoma was in the pia mater.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00315665
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  • 38
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    Electronic Resource
    The vascular architecture of human xenotransplanted tumors: histological, morphometrical, and ultrastructural studies (1990)
    Springer
    Journal of cancer research and clinical oncology 116 (1990), S. 517-524 
    Details
    ISSN: 1432-1335
    Keywords: Tumor vascularization ; Tumor blood flow ; Xenograft ; Nude mouse ; Vascular corrosion cast ; Ultrastructure ; Electron microscopy ; Heterogeneity ; Vessel morphology ; Morphometry ; Necrosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study was designed to examine the vascular system of human xenotransplanted tumors on nude mice with different complementary morphometrical and morphological methods. The vascular system shows a chaotic arrangement. There is an extreme heterogeneity in the vascular distribution and density. Large avascular regions could be identified in several non-necrotic tumors. There was no clear difference in the vascular density between the center and the periphery of the tumors, nor was there any zonal correlation for the distribution of the necrosis. With three-dimensional corrosion casts it could be demonstrated that clusters of vessels were directly beneath areas almost free of vessels. In the center, vessels often form a sinusoidal system with numerous blind ends without clearly discernible endothelial cells. Numerous irregular tumor-cell-lined sinusoids are visible next to endothelial-lined vessels with transmission electron microscopy. With scanning electron microscopy it could be demonstrated that large-calibre endotheliazed vessels were found in the direct vicinity or in the center of non-viable zones. Even large-calibre vessels have a capillary wall structure. Sometimes, a basement membrane cannot be observed at all or only incompletely. There are numerous indications of vascular discontinuities and leaks with a widespread intercellular occurrence of blood cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01613005
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  • 39
    Electronic Resource
    Electronic Resource
    Differentiation of mast cells during postnatal development of neonatally estrogen-treated rats (1990)
    Springer
    Cell & tissue research 259 (1990), S. 25-31 
    Details
    ISSN: 1432-0878
    Keywords: Testis ; Mast cells ; Estrogen ; Cytochemistry ; Electron microscopy ; Rat, Wistar
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The accumulation of mast cells in the testicular interstitium of neonatally estrogen-treated rats was studied from 15 to 90 days of age. The maturation of these cells was assessed by ultrastructural analysis and their histochemical properties were examined with the sequential alcian blue-safranin staining method. The first identifiable mast cells appeared in the testis at 17–20 days of age, as immature cells with proliferative capacity. The density of mast cells increased up to 45 days of age, showing a slight decrease from 45 to 90 days of age. Before 45 days of age, most mast cells showed alcian blue-stained granules, whereas at 45 days of age, most cells presented a mixture of alcian blue and safranin-stained granules. From this age onward, most cells were stained with safranin. These maturational changes were well-correlated with their ultrastructural features. Mast cells presented few and heterogeneous immature granules up to 45 days of age, and many uniform electron-dense granules at 90 days of age. These results indicate that the testicular interstitium of neonatally estrogen-treated rats provides an adventageous environment for the recruitment, proliferation and maturation of connective tissue mast cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00571426
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  • 40
    Electronic Resource
    Electronic Resource
    Keratin filaments of epithelial and taste-bud cells in the circumvallate papillae of adult and developing mice (1990)
    Springer
    Cell & tissue research 260 (1990), S. 41-48 
    Details
    ISSN: 1432-0878
    Keywords: Keratin filament ; Circumvallate papilla ; Taste bud ; Immunocytochemistry ; Electron microscopy ; Mouse (dd)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Keratin filaments of epithelial- and taste-bud cells in the circumvallate papillae of adult and developing mice were studied by immunocytochemistry using monoclonal antikeratin antibodies (PKK2 and PKK3) and by conventional electron microscopy. Elongated cells (type-I,-II, and-III cells) of the taste buds were stained by PKK3 antibody, which reacts with 45-kdalton keratin, whereas basal cells of the taste buds and surrounding epithelial cells showed negative staining with PKK3. Such PKK3-reactive cells occurred at 0 day after birth, when taste-buds first appeared in the dorsal surface epithelium of the papillae. Thus 45-kdalton keratin seems to be an excellent immunocytochemical marker for identifying taste-bud cells. Epithelial cells in all layers of the trench wall and basal layer cells of the dorsal surface contained densely aggregated bundles of keratin filaments that reacted with PKK2 antibody, but not with PKK3. In contrast, taste-bud cells and spinous and granular layer cells of the dorsal surface possessed loose aggregated bundles of filaments that reacted with PKK3, but not with PKK2. These results suggest that the aggregation and distribution pattern of keratin filaments may reflect differences in the keratin subtypes that comprise these filaments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00297488
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  • 41
    Electronic Resource
    Electronic Resource
    Crystalloid lysozyme inclusions in Paneth cells of vitamin A-deficient rats (1990)
    Springer
    Cell & tissue research 260 (1990), S. 625-628 
    Details
    ISSN: 1432-0878
    Keywords: Vitamin A-deficiency ; Paneth cells ; Crystalloid lysozyme ; Tubular structures ; Intestinal local immunity ; Electron microscopy ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effect of vitamin A-deficiency on jejunal Paneth cells in rats was investigated. Crystalloid particles were observed in secretion granules of Paneth cells from 6 out of 8 rats with vitamin A-deficiency. The particles were similar to those found in Paneth cells under other experimental conditions. Using an immuno-electron-microscopic technique we demonstrated a clear lysozyme immunoreactivity of these particles. In 2 vitamin A-deficient rats tubular structures have been detected in addition to the crystalloid particles. Crystalloid particles or tubular structures were not detectable in a control group of 8 vitamin A-supplemented rats. The morphological alterations of Paneth cells may be correlated to an impaired local immunity of the intestine during vitamin A-deficiency.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00297244
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  • 42
    Electronic Resource
    Electronic Resource
    A freeze-etch study of angular marginal-plate-containing peroxisomes in the proximal tubules of bovine kidney (1990)
    Springer
    Cell & tissue research 260 (1990), S. 409-414 
    Details
    ISSN: 1432-0878
    Keywords: Kidney ; Peroxisomes ; Marginal plates ; Electron microscopy ; Freeze-etching ; DAB-cytochemistry ; Bovine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of peroxisomes in the proximal nephron tubules of bovine kidney cortex was studied using ultrathin-sectioning, diaminobenzidine cytochemistry for the visualization of catalase, and by freeze-fracture. Peroxisomes in this nephron segment are up to 1.5 μm in diameter and exhibit a peculiar angular shape, which is probably related to the occurrence of multiple straight plate-like inclusions (marginal plates) in the matrix of peroxisomes; they lie directly underneath the peroxisomal membranes. The peroxisomal membrane in such regions follows the outline of the marginal plate. The peculiar shape of peroxisomes allows their unequivocal identification in freeze-fracture preparations. Peroxisomal membranes are recognized by their flat, often rectangular appearance. Intramembrane particles are much more numerous on P-fracture faces than on E-fracture faces. A crystalline lattice-structure with a periodicity of approximately 10 nm can be observed on the flat rectangular areas of E-fracture faces. This lattice structure is intensified after prolonged freeze-etching. Intramembranous particles seem to be superimposed over this pattern. The crystalline pattern on the E-fracture faces of peroxisomal membranes is probably not a membrane structure but it reveals the structure of the membrane-associated marginal plates. A cast of the marginal-plate surface may be generated by a collapse of the peroxisomal membrane half onto the immediately underlying matrix inclusion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318644
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  • 43
    Electronic Resource
    Electronic Resource
    Intragranular co-storage of neuropeptide Y and arginine vasopressin in the paraventricular magnocellular neurons of the rat hypothalamus (1990)
    Springer
    Cell & tissue research 262 (1990), S. 47-52 
    Details
    ISSN: 1432-0878
    Keywords: Neuropeptide Y ; Arginine vasopressin ; Co-storage ; Immunohistochemistry ; Electron microscopy ; Paraventricular nucleus ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Certain populations of arginine vasopressin (AVP) neurons in the magnocellular paraventricular nucleus became immunoreactive for neuropeptide Y (NPY) when rats were treated with colchicine or monosodium glutamate (MSG). The co-storage of these peptides was examined by empooying a post-embedding electron-microscopic immunohistochemistry technique using goldlabeled antibodies to the two peptides. In colchicinetreated rats, the neuronal perikarya contained numerous secretory granules showing co-storage of the two peptides. The cells of the MSG-treated rats were characterized by having well-developed Golgi bodies with the granular structures also co-storing the two peptides, although the secretory granules in the perikarya were rather fewer than in the colchicine-treated rats. It is concluded that the destruction of the arcuate nucleus by MSG-treatment may potentiate the synthesis of NPY in AVP neurons, the synthesis of which is latent in intact animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00327744
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  • 44
    Electronic Resource
    Electronic Resource
    Structural changes during the first divisions of embryos resulting from anther and free microspore culture inBrassica napus (1990)
    Springer
    Protoplasma 156 (1990), S. 149-162 
    Details
    ISSN: 1615-6102
    Keywords: Anther embryogenesis ; Brassica napus ; Electron microscopy ; Histochemistry ; Microspore embryogenesis ; Pollen division
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Ultrastructural and cytochemical features of embryo development during anther and free microspore culture inBrassica napus have been followed from the late uninucleate microspore stage through the first embryonic division. On transfer to culture, the microspore cytoplasm possesses a large vacuole, often containing electron opaque aggregates, and a peripheral nucleus. Mitochondria, endoplasmic reticulum and starch-free plastids are distributed throughout the cytoplasm. The conditions of culture induce a number of major changes in the cytoplasmic organisation of the microspore. First, the central vacuole becomes fragmented allowing the nucleus to assume a central position within the cell. Secondly, starch synthesis commences in the plastids which, in turn, are seen to occupy a domain investing the nucleus. Thirdly, the cell develops a thick fibrillar wall, situated immediately adjacent to the intine of the immature pollen wall. Finally, the microspores develop large cytoplasmic aggregates of globular material. The nature of this substance remains unknown, but it remains present until the young embryos have reached the 30 cell stage. The first division of cultured microspores destined to become embryos is generally symmetrical, in contrast to the asymmetric division seen in normal development in vivo. Consideration is given to the differences observed between embryos developing from anthers and free microspores in culture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01560653
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  • 45
    Electronic Resource
    Electronic Resource
    Localization of acid phosphatase in lactating rat mammary glands (1990)
    Springer
    Protoplasma 153 (1990), S. 149-156 
    Details
    ISSN: 1615-6102
    Keywords: Acid phosphatase ; Electron microscopy ; Mammary glands ; Subcellular fractions ; Substrate specificity ; Sulfhydryl agents ; Tartrate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Localization of acid phosphatase in mammary glands of lactating rats was studied by both biochemical and cytochemical methods. Cytochemically, acid phosphatase activity was detected by using lead citrate as the capture agent for the inorganic phosphate released from p-nitrophenyl phosphate. The activity was predominantly localized in the lumina of the endomembrane system and in the milk that had been secreted into the alveolar lumen. Biochemically, acid phosphatase was present in all the subcellular fractions with higher activities in the membrane-associated fractions. The localization of tartrate-resistant acid phosphatases within the endomembrane system of fully lactating rat mammary tissue suggests a possible role for these enzymes in milk secretory processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01353999
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  • 46
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    Electronic Resource
    Tubulin conformation in microtubule-free cells ofVigna sinensis (1990)
    Springer
    Protoplasma 154 (1990), S. 132-143 
    Details
    ISSN: 1615-6102
    Keywords: Vigna sinensis ; Immunofluorescence ; Electron microscopy ; Colchicine ; Tubulin reticulum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The primary leaf, epicotyl, and root cells ofVigna sinensis seedlings grown continuously in a 0.08% colchicine solution, become microtubule-free and polyploid. In meristematic root cells a tubulin transformation is detected 1–3 h after the treatment had begun. Tubulin strands are organized at the positions of the pre-existing microtubules. Frequently, the strands converge on or are organized in the cortical cytoplasmic zone where in normal cells the preprophase microtubule band (PMB) is assembled. In meristematic root cells subjected to a 6–12 h colchicine treatment, the tubulin strands become perinuclear, entering the cortical cytoplasm at regions close to the nucleus. One day after the onset of the treatment, tubulin generally forms a continuous reticulum of interconnected strands in all the organs examined. In most cells this reticulum surrounds the nucleus partly or totally or lies close to it, exhibiting variable configurations in different cells. After prolonged treatments, the organization of the tubulin reticulum changes further. Now this consists of crystal-like structures interconnected by thin strands. On thin sections of fixed tissue the tubulin strands consist of paracrystalline material. The distribution of this material in the affected cells coincides with that of tubulin reticulum visualized by immunofluorescence. In transverse planes each strand exhibits circular subunits arranged close to one another in a hexagonal pattern but in longitudinal ones variable images were observed. The paracrystalline material persists in root cells subjected to an 8-day continuous colchicine treatment. The immunolabeled strands seem to be composed of tubulin-colchicine complexes and not pure tubulin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01539840
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  • 47
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    Electronic Resource
    Lipofuscin pigments in the spiral ganglion of the rat (1990)
    Springer
    European archives of oto-rhino-laryngology and head & neck 247 (1990), S. 189-193 
    Details
    ISSN: 1434-4726
    Keywords: Spiral ganglion ; Lipofuscin ; Ceroid ; Vitamin E deficiency ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The purpose of the present study was to clarify morphological differences in lipofuscin or so-called age pigments observed in the spiral ganglion cells of both young and adult rat groups and to characterize the size and structure of ceroid pigment granules generated in vitamin-E-deficient rats. The results showed different patterns of lipofuscin distribution in the two groups. The adult rat group had large aggregated lipoid, dark pigment granules of irregular shape in the cytoplasm. In contrast, the young group had small numbers of small, dense homogeneous granules, suggesting higher Schwann cell phagocytic activity. The ceroid pigments apparently included numerous vesicles and droplets of more variable density and size than the lipofuscin pigments appearing in the non-treated older animals. Both lipofuscin and ceroid pigments developing in such non-dividing cells are produced as a result of peroxidation reactions, so that the more they accumulate in the cytoplasm the more likely cell function deteriorates. The present study has shown that lipofuscin/ceroid granules are generated in the spiral ganglions under either endogenous (aging) or exogenous (vitamin E deficiency) conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00175975
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  • 48
    Electronic Resource
    Electronic Resource
    A hyaluronate secretor in the nasal mucosa: a cytochemical study using hyaluronidase-gold (1990)
    Springer
    European archives of oto-rhino-laryngology and head & neck 247 (1990), S. 237-239 
    Details
    ISSN: 1434-4726
    Keywords: Hyaluronate ; Hyaluronidase-gold ; Nasal mucosa ; Goblet cells ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructural distribution of hyaluronate in the nasal mucosa of Wistar rats, especially in secretory cells, was examined by hyaluronidase-gold labeling using electron microscopy. The main secretor of hyaluronate in the nasal mucosa was found to be the goblet cells and not the nasal glands.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00178993
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  • 49
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    Electron microscopic demonstration of sialic acid residues in the organ of Corti with lectin from Limax flavus (1990)
    Springer
    European archives of oto-rhino-laryngology and head & neck 247 (1990), S. 240-243 
    Details
    ISSN: 1434-4726
    Keywords: Organ of Corti ; Limax flavus ; Feutin-gold ; Electron microscopy ; Sialic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The localization of sialic acid (N-acetyl- and N-glyconylneuraminic acid) in the organ of Corti of the mongolian gerbil was examined with electron microscopy by postembedding labeling using Limax flavus agglutinin and feutin-gold. Gold labeling was observed on the fibrous structure of the tectorial membrane, the basilar membrane and the spiral limbus. The labeling was also observed on the cuticular plate of the hair cells, the head and cone of the pillar cells and the head plate of Deiters' cells and other supporting cells. Collagen or cytoskeletal glycoproteins are suggested to be the source of the sialic acid in these structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00178994
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  • 50
    Electronic Resource
    Electronic Resource
    Mesothelium of Reissner's membrane in guinea pigs: an electron microscopic study (1990)
    Springer
    European archives of oto-rhino-laryngology and head & neck 248 (1990), S. 57-62 
    Details
    ISSN: 1434-4726
    Keywords: Vestibular membrane ; Reissner's membrane ; Mesothelium ; Fixation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The mesothelial cells of Reissner's membrane in guinea pigs were found to be connected by junctional complexes. No cell discontinuities or gaps were observed by scanning or transmission electron microscopy. These results are not in accordance with previous studies. They were achieved by in vivo vascular perfusion fixation, handling of cochleae in protective specimen carriers, thiocarbohydrazide treatment and continuous dehydration. Findings in the present study indicate that the interepithelial space between the epithelial and mesothelial cell layers constitutes a specific compartment which must be considered when examining solute transport over Reissner's membrane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00634783
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  • 51
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    Electronic Resource
    Masthead (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230101
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  • 52
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    Electronic Resource
    Chrom-Komplexe mit cyclo-Asx-Liganden (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 3-6 
    Details
    ISSN: 0009-2940
    Keywords: Pentaarsacyclopentadienyl ligand / Triarsachromatertrahedranes / Triple-decker complexes / Tetrahedrane, triarsachroma- ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chromium Complexes with cyclo-Asx, LigandsThe interaction of [(η5C5Me4R)(CO)2Cr]2(Cr≡Cr) (1a: R = CH3 1b: R = C2H5) with yellow arsenic (As4) affords the triarsachromatetrahedranes [(η5-C5Me4R)(CO)2Cr(η3-As3)] (2a, b) as well as the 27-VE triple-decker complexes [{(η5-C5Me4R)Cr}2-(μ,η5-As5)] (3a, b) 3 is also formed photochemically from 2. 2a and 3b have been characterized by X-ray structure analyses. The cyclo-As5 ligand forms a regular arsenic pentagon.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230102
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  • 53
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    Bindung von Monosacchariden über die Isocyano- und Carben-Funktion an das Metall-Atom: Chrom(0), Wolfram(0)-, Rhodium(III)-, Iridium(III)-, Palladium(II)-, Platin(II)- und Gold(I)-Komplexe von 1,3,4,6-Tetra-O-acetyl-2-desoxy-2-isocyano-α-D-glucose und - β-D-glucose (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 11-17 
    Details
    ISSN: 0009-2940
    Keywords: Isocyanide complexes / Carbene complexes / Transition metal complexes / Carbohydrates / Glucose, 2-deoxy-2-isocyano-, as complex ligand ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metal-Complexes of Biologically Important Ligands, LII. - Binding of Monosaccharides through the Isocyano and Carbene Group to the Metal Atom: Chromium(O), Tungsten(O), Rhodium(III), Iridium(1II). Palladium(I1). Platinum(ZI), and Gold(1) Complexes of 1.3.4.6-Tetra-O-acetyl-2-deoxy-2-isocyano-α-D-glucose and -β-D-glucoseStable isocyanide complexes cis-Cl2Pd(CNR)2 (2), cis-Cl2Pt(CNR)2 (3), cis-Cl2Pt(PPh3)CNR (4), [trans-(Ph3P)2Pt(Cl)CNR]+BF-4 (5), ClAuCNR (6), (OC)5CrCNR (7), (OC)5WCNR (8), (η5-C5Me5)Rh-(CNR)Cl2 (9), (η5-C5Me5)Ir(CNR)Cl2 (10) of 1,3,4,6-tetra-O-acetyl-2-deoxy-2-isocyano-α(β)-D-glucose (CNR) as well as carbene complexes ClAuC(NHR')(NHR) (11, 12) and cis-Cl2Pt(PPh3)C-(OR')NHR (13, 14) have been prepared and characterized by their IR and NMR spectra. The structure of 10 has been determined by X-ray crystal structure analysis.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230104
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  • 54
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    Übergangsmetall-substituierte Acylphosphane und Phosphaalkene, XII1. - Übergangsmetall-Schwefelylid-Komplexe, XXVII2) Zur Umwandlung des Phosphaalkenyleisen-Komplexes (η5-C5Me5)-(CO)2FeP=C(SiMe3) 2 in η3-Phosphaallyleisen-Komplexe mittels Me2S(O)=CH2: Synthese und Molekülstruktur der beiden Isomeren von (η5-C5Me5)(CO)Fe{η3-P[CH(SiMe3)2](CHC=O)} (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 23-28 
    Details
    ISSN: 0009-2940
    Keywords: Phosphaallyl complexes / Sulfur ylides ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transition-Metal-Substituted Acylphosphines and Phosphaalkenes. XII. - Transition-Metal Sulfur Ylide Complexes, XXVIIzt - Conversion of a Phosphaalkenyliron Complex (η5-C5Me5)-(CO)2FeP=(SiMe3)2 into (η3-Phosphaallyl)iron Complexes by means of Me2S-(O)=CH2: Synthesis and Molecular Structures of Two Isomeres of (η5-C5Me5)-(CO)η5-P(CH-(SiMe3)2(CHC-0)}The transition-metal-substituted phosphaalkene (η5-C5Me5)-(CO)2FeP=C(SiMe3)2 (1) reacts with the sulfur ylide Me2S-(O)=CH2 (2) to afford the yellow η3-phosphaallyliron complex 4 with a syn-configuration in the organophosphorus ligand. In toluene solution at 40°C this complex undergoes an isomerization to the corresponding anti-configurated complex 5. Constitution and configuration of both compounds were elucidated by spectroscopic methods (IR, 1H, 13C, 31P NMR, and MS) as well as single-crystal X-ray diffraction analyses.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230106
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  • 55
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    Diphosphabicyclobutane (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 67-69 
    Details
    ISSN: 0009-2940
    Keywords: Diphosphabicyclobutanes / Valence isomerization ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: DiphosphabicyclobutanesTwo isomeric diphosphabicyclobutanes (5,11) are obtained by treatment of the phosphaalkenes X-P = C(Ph)Tms (1a) and X - P = CTms2 (1b) (X = halogen Tms = trimethylsilyl) with 2, Mg, or Na. Both syntheses proceed by coupling of two phosphaalkene units affording, however, two different diphospha-butadiene intermediates. 4 and 10 readily undergo isomerization reactions to form the diphosphabicyclobutanes. Irradiation of the phosphaalkenes Cp* - P = C(Ph)Tms (12a) and Cp* - P = CTms2 (12b) (Cp* = C5Me5) gives rise to a different reaction pathway. Dimerization of 12a, followed by homolytic cleavage of the Cp* - phosphorus bond and intramolecular recombination produces the butterfly compound 5, whereas homolytic cleavage of the Cp* - element bond in 12 b, followed by rearrangement and intermolecular recombination, affords the diphosphabicyclobutane 11.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230113
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  • 56
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    Mononuclear Bis(diazadiene)ruthenium(0) Complexes and the Coupling of Butadiene to a Diazadiene System (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 83-85 
    Details
    ISSN: 0009-2940
    Keywords: Diazadienes/Carbon-carbon coupling/Ruthenium(0) complexes/Ethylene complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Complexes (dad)2RuCl2 (1) (dad = diazadiene, RN = CR'- CR'=NR) are reduced to (dad)2Ru (2) which react with L = CO or ethylene to give (dad)2RuL (3,5). Reduction of 1b ( R' = H) with magnesium-butadiene or reaction of 2b with butadiene leads to a new type of C-C coupling of butadiene to one of the diazadiene ligands (6b). Addition of CO induces a rearrangement to 7b by a hydride shift.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230117
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    Light-Induced Conversion of 4,6,7,8-Tetrahydro-2H-benzopyran-2,5(3H)-diones into 3,5,6,7-Tetrahydrobenzofuran-4(2H)-ones in Methanol (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 101-105 
    Details
    ISSN: 0009-2940
    Keywords: Enol lactones, photochemistry of / Ketene photoextrusion / Ketones, photoreduction / 0-Heterocycles, photochemistry of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The photochemical conversion of 4,4,7,7-tetramethyl-4,6,7,8-tetrahydro-2H-benzopyran-2,5(3H)-dione (1) into 3,3,6,6-tetramethyl-3,5,6,7-tetrahydrobenzofuran-4(2H)-one (4) in methanol does not - as previously assumed - proceed by decarbonylation of the primarily formed acyl-vinyloxy biradical 2. This conclusion results from the finding that C-2, i. e. the CH2 group, of benzofuranone 4 stems from the solvent. Similar observations were made for other benzopyrandiones 15. A reaction sequence consisting of (a) ketene elimination from 2 with formation of 2-isopropylidene-5,5-dimethyl-1,3-cyclo-hexanedione and (b) light-induced (reductive) H . and . CH2OH addition to this intermediate followed by cyclization and dehydration to 4, is proposed for the conversion 1→4.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230121
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  • 58
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    Synthese von Sieben- und Achtring-anellierten Pyridinen durch “inverse” intramolekulare Diels-Alder-Reaktion mit Trifluormethyl-substituierten 1,2,4-Triazinen (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 133-136 
    Details
    ISSN: 0009-2940
    Keywords: 1,2,4-Triazines / Dienophiles, side-chain / [4+21 Cycloaddition / Pyrido[2,3-e-l,4-diazepines / Pyrido[2,3-b]-1,5-diazocines ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of Seven- and Eight-Membered Ring-Annulated Pyridines by “Inverse” Intramolecular Diels-Alder Reaction with Trifluoromethyl-Substituted 1,2,4-TriazinesIntramolecular [4 + 2] cycloaddition reactions with inverse electron demand of trifluoromethyl-substituted 1,2,4-triazines carrying 7- or 8-membered o-alkyne side-chain dienophiles (3,8,12) lead to the synthesis of bicyclic pyridines with annulated heterocyclic seven- (5, 9, 13-15) or eight-membered rings (19, 22, 23, 26).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230125
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  • 59
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    Synthesen und Strukturen neuer Komplexes des 2,2′-Bipyridins mit Niob, Molybdän, Wolfram und Rhenium in hohen Oxidationsstufen (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 271-276 
    Details
    ISSN: 0009-2940
    Keywords: Niobium complexes / Molybdenum complexes / Tungsten complexes / Rhenium complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses and Structures of New 2,2′-Bipyridine Complexes of Niobium, Molybdenum, Tungsten, and Rhenium in High Oxidation StatesExchange of oxo for chlorine ligands by means of hexamethyl-disiloxane provides an easy and effective synthesis of the oxo halides (bipy)MVOCl3 (bipy = 2,2′-bipyridine, C10H8N2; M = Nb, 1c; Re, 2c; W, 3c) and (bipy)MVIO2Cl2 (N = Mo, 6a;W, 6b). Starting from ReCl5 the structurally (X-ray) characterized byproduct (bipy)ReIVCl4 (2b) is also formed. Dirhenium heptaoxide (7) is converted into the complex (bipy)ReVIIO3Cl (8) upon treatment with chlorotrimethylsilane in the presence of 2,2′-bipyridine, thus being now easily available a key compound in rhenium chemistry. The new imido complexes of composition (bipy)MoVI(NR)2Cl2 [R = C(H3)3, 9a; C6H5, 9b] are accessible from 6a and the corresponding silylated amines. The rhenium and tungsten complexes 2b and 6b, resp., exhibit octahedral structures in the crystal, with that of 6b being distorted as a result of different ligands and intermolecular contacts.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230208
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  • 60
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    Ungewöhnliche Reaktion eines Diazaphosphetidinthions mit Trimethylsilylazid (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 289-292 
    Details
    ISSN: 0009-2940
    Keywords: Diazaphosphetidinethione / Trimethylsilyl azide / Migration, methyl group, trimethylsilyl group ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Unusual Reaction of a Diazaphosphetidinethione with Trimethylsilyl Azide2-Dimethylamino-1,3-dimethyl-1,3-diaza-2-phosphetidine-4-thione (1) and trimethylsilyl azide do not react with formation of the expected phosphane imine 2. Instead, (a) addition of trimethylsilyl azide to the °C=S group of 1, (b) sulfurization of the phosphorus atom of 1 and formation of the racemic thiophosphoryl compound 3 (as a result of intramolecular methyl/trimethylsilyl migration) take place. For 3 two pairs of diastereomers are discussed, which have been studied by 1H-, 13C- and 31P-NMR spectroscopy, and through a 1H-13C NMR correlation.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230211
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  • 61
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    Photo Diels-Alder Additons, V1 1,4-Photoadditions of α-Morpholinoacrylonitrile to 1-Acylnaphthalenes (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 315-319 
    Details
    ISSN: 0009-2940
    Keywords: Cycloadditions, regio- and stereoselective, light-induced / 1,4-Ethanonaphthalenes / Captodative alkenes / Di-π-methane rearrangement ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photoexcited 1-naphthaldehyde (1a), 1-acetonaphthone (1b), and 1-naphthophenone (1c) add α-morpholinoacrylonitrile (2a) in a [4 + 2] mode with exceptional regio- and stereoselective formation of only one diastereomer of the two possible regioisomeric 1,4-dihydro-1,4-ethanonaphthalene adducts. An independently formed 1,2-adduct 4 was detected and isolated in very low yield, 4 is thermally and photochemically (313-nm, excitation) cleaved into the starting materials with no indication of direct interconversion into 3b. Compound 3b is stable towards 313-nm radiation, but is efficiently isomerized to give the dihydrobenzosemibullvalene 7 upon 254-nm excitation. - All observations point to the first excited triplet state as the starting point for the 1,4-additions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230216
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  • 62
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    Stereochemistry of Dewar Benzenes - Molecular Structures Influenced by Electronic and Steric Effects (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 345-350 
    Details
    ISSN: 0009-2940
    Keywords: Dewar benzene, derivatives, molecular structures of / Substituent effects on molecular structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The molecular structures of the four Dewar benzene derivatives 4-7 were determined by means of X-ray diffraction. The central C1-C4 bonds are extremely long. The carboxylate groups on the bridgehead carbon atoms of 4, 5, and 7 are in optimal orientation for an electronic interaction with the central bonds having high p-character. Therefore the central bonds in 4, 5, und 7 (1.602-1.612 Å) are even more elongated than in 6 (1.563 Å). Repulsion between tert-butyl groups causes bond lengthening and structural deformations. The sp2-hybridized carbon atoms are pyramidalized. From structural comparison of Dewar benzene derivatives a strong correlation between the length of the central bond and the folding angle of the four-membered rings can be derived. A new rule has been established for the thermal stability of Dewar benzene derivatives.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230220
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  • 63
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    Neue wasserlösliche makrobicyclische Großhohlräume (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 375-379 
    Details
    ISSN: 0009-2940
    Keywords: Cyclophanes / Hostguest chemistry / Macrocyclic compounds / Phanes / Supramolecular chemistry ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New Watersoluble Macrobicyclic CavitiesThe watersoluble macrobicyclic compounds 1, 3, 5a, and 5b have been synthesized for the first time bearing large endolipophilic cavities of different sizes and shapes. They were studied with respect to their interactions towards lipophilic guest compounds. The “in/out” isomerism of the hitherto largest endolipophilic cavities 4a, 4b, 5a, and 5b has been investigated by 1H-, 13C-NMR spectroscopy and FAB mass spectrometry. The absence of significant 1H-NMR high-field shifts in hostguest studies is attributed to the rigidity of cavities 1 and 3, whilst the isomeric cavities 5a and 5b contain very large openings. Orientational fluorescence spectroscopy investigations, however, suggest hostguest interactions of the isomers 5a and 5b with ammonium 8-anilino-1-naphthalenesulfonate (8,1-ANS).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230224
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  • 64
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    Elektrophile β-Bromierung und nucleophile α-Methoxylierung α,β-ungesättigter Carbonylverbindungen (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 399-404 
    Details
    ISSN: 0009-2940
    Keywords: β-Halovinyl ketones / β-Halovinyl aldehydes / α-Alkoxyvinyl ketones ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electrophilic β-Bromination and Nucleophilic α-Methoxylation of α,β-Unsaturated Carbonyl CompoundsOximes 29a, b, semicarbazones 11a-d, dimethylhydrazones 4, and [3-methyl-2(3H)-benzothiazolylidene]hydrazones 23a-c of unsaturated aldehydes and ketones are brominated at the β-carbon by an addition-elimination sequence (→ 21a,b, 13a-d, 7, and 27c, respectively). When unsaturated ketone hydrazones are treated with bromine and methanol the α-methoxy-β-bromo derivatives 35a-c are obtained, which after hydrolysis and hydrobromic acid elimination give α-methoxy substitution products 36a-c of the starting compounds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230227
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  • 65
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    Electron-Density Distribution in the Bonds of a Dewar Benzene Derivative (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 341-343 
    Details
    ISSN: 0009-2940
    Keywords: Difference electron densities / Dewar benzene, derivative ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We determined the difference electron densities [X-X] in the bonds of a Dewar benzene derivative from low temperature X-ray data (94 K). The density maxima on all bonds are significant. The central bond with an internuclear distance of 1.594 Å has a strong bending character. From the difference densities a bending angle of 28° can be derived.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230219
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  • 66
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    Zur Stereoselektivität der intramolekularen Diels-Alder-Reaktion von 1,7,9-Decatrien-3-onen zu Octalonderivaten (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 363-374 
    Details
    ISSN: 0009-2940
    Keywords: Diels-Alder reaction, intramolecular / 1,7,9-Decatrien-3-ones / Octalone derivatives / Siloxycyclopropanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Stereoselectivity of Intramolecular Diels-Alder Reactions of 1,7,Q-Decatrien-3-ones to Octalone Derivatives2-Alkenyl-substituted 2-siloxycyclopropanes 1 and 2 serve as protected enone equivalents and are converted into key building blocks 5-8 in excellent yields. After desilylation and ring cleavage these compounds provide 1,7,9-decatrien-3-ones 9-12, which undergo smooth intramolecular Diels-Alder reaction at room temperature or approximately 100°C. The resulting octalone derivatives 13-16 are formed with exclusive or preferred cis connection of the rings. The relative configurations of the cycloadducts are secured by equilibration experiments and NMR spectroscopy (selective proton decouplings). For 11 → 15 and 12 → 16 the cis selectivitiy can remarkably be enhanced by trifluoroacetic acid catalysis. This high noninduced diastereoselectivity is caused by the endo approach of the reactive molecular sites, whereas the configuration of the third stereogenic centre (C-2) is determined by the folding of the linking carbon chain. Preference of a boat conformation with equatorial ester group endo-Beq may be assumed and appears to be general for intramolecular cycloadditions of such trienones. This effect as well as the influence of further substituents at the diene or dienophile portion on stereoselectivity and the reactions of other model compounds are discussed.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230223
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    Novel Access to Polyazamacrocycles: Non-Template Cyclization of Terephthalaldehyde and Aliphatic Polyamines (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 405-406 
    Details
    ISSN: 0009-2940
    Keywords: Polyazamacrocycles / Cyclization, non-template / Terephthalaldehyde / Polyamines ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Non-template [2+2] condensation of terephthalaldehyde with bis(3-aminopropyl)amine and N,N'-bis(3-aminopropyl)-1,2-diaminoethane leads to macrocyclic systems that can be reduced and derivatized further, whereas a similar reaction with bis(2-aminoethyl)amine leads to polymeric material only.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230228
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  • 68
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    Deuterierte Bicyclo[3.2.0]heptan-2-one und ihre NMR-Spektren (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 411-412 
    Details
    ISSN: 0009-2940
    Keywords: Bicyclo[3.2.0]heptan-2-one, deuterated ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Deuterated Bicyclo[3.2.0]heptan-2-ones and their NMR Spectra[3,3-2H2]-, [6,7-2H2]-, [6,6-2H2]-, and [7,7-2H2]bicyclo[3.2.0]heptan-2-ones were prepared, starting from 2-cyclopenten-1-one (1). Using these derivatives, the 13C- and 1H-NMR spectra of bicyclo[3.2.0]heptan-2-one (2) have been assigned.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230230
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    Die Borierung von Lactamen und Harnstoffen mit einem Amino-imino-boran (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 455-458 
    Details
    ISSN: 0009-2940
    Keywords: N-Boryl lactams / Isourea, triborated / Isothiourea, triborated /N/O Borotropism / Calculations, MNDO ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Contribution to the Chemistry of Boron, 201. - Boration of Lactams and Ureas by an Amino-Imino-BoranePyrrolidon reacts with (tert-butylimino)(2,2,6,6-tetramethylpiperidino)borane (1) to give the N-borated lactam 2. Diketopiperazine behaves similarly. It is borated on both of its N atoms to form 3. Urea and 1 give access to the O,N,N′-triborated isourea derivative 4, which contains the structural unit of a ketiminoborane. The diborated carbodiimide 10 is ultimately obtained from 1 and thiourea via the triborated isothiourea derivative 9. MNDO calculations have been used to estimate the relative thermodynamic stabilities of O/N borotropes of carbonic acid amides and lactams. They demonstrate that the O isomers gain in stability by increasing the size of N substituents.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230307
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    Lithium-Verbindungen eines Chlorsilanols und von Fluor-funktionellen Siloxanolen; Reaktionen und Kristallstrukturen (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 449-453 
    Details
    ISSN: 0009-2940
    Keywords: Lithium salts / Chlorosilanol / Fluorosilanolates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Lithium Compounds of a Chlorosilanol and of Fluoro-Functional Siloxanols; Synthesis and Crystal StructuresThe lithiated disilanol (CMe3)2Si(OH)2 (1) serves as a starting material in the reaction with halosilanes for the stepwise construction of siloxanols (4, 5, 7). 4 and 7 react with n-C4H9Li to give the lithium compounds 6 and 8, respectively. 6 crystallizes in hexane as a trimer with planar three-coordinated lithium, bonded to two Si-O atoms and one Si - F atom. 8 reacts in THF with LiF elimination to give cyclotrisiloxane 9. The chlorosilanol 2 is prepared by hydroxy-chlorine exchange in 1 with PCl5. The stable lithium derivative of 2 (3) forms a dimeric THF adduct with tetrahedral lithium.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230306
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    Chemistry of the Heterocyclic Pseudobasic Amino Alcohols, XXXVIII Ring-Chain Tautomerism of Pyrimido[6,1-a]isoquinolines (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 493-498 
    Details
    ISSN: 0009-2940
    Keywords: Pyrimido[6,1-a]isoquinolines / Pseudobases, heterocyclic / Ring-chain tautomerism ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In basis media, 4-substituted pyrimido[6,1-a]isoquinolin-2-imine hydrochlorides (4) constitute an equilibrium system involving the tautomeric forms characteristic of pseudobases 5, 6, 7 and the anhydro base 9. In aqueous solution in the pH range 7-13 the ammonium hydroxide form 5 is present. Between pH 13 and 14 the pseudobase 6 probably arises from this by covalent binding of the hydroxy group. 6 is then converted to the more stable imino type anhydrobase 9. Ring cleavage of 4 by excess alkali or of 9 by a small amount of water gives 1-(acylamidinomethylen)isoquinolines 7. Compounds 7 and 9 are stable in the solid state or in aprotic solutions but revert to cation 5 in dilute protic solutions.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230315
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    [2.2](2,6)- and [2.2](2,5)Pyrazinophanes: Synthesis and Molecular Structure (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 523-533 
    Details
    ISSN: 0009-2940
    Keywords: Hofman 1,6-elimination / Pyrazine derivatives / [2.2]Pyrazinophanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title compounds 1-3 and their methyl derivatives 4-7 were synthesized 2,11-dithia[3.3]pyrazinophanes 24-26 or by Hofmann 1,6-elimination of the appropriate [(5-methyl-2-pyrazinyl)methyl]trimethylammonium hydroxides followed by dimerization of the generated 2,5-dihydro-2,5-dimethylenepyrazines. α-Chlorination of the methylpyrazines 8-10 with N-chlorosuccinimide gave the required precursors 11, 12, 14, 17 and 18. The results of the X-ray structure determinations for 1-4 and 7 which indicate an unequivocal isomer assignment are discussed with regard to steric strain in these molecules. The electronic spectra of the pyrazinophanes 7-7 are reported and compared with those of the parent methylpyrazines.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230319
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    Asymmetric Induction in the Wittig-Still Rearrangement of Ethers Containing an Allylic Stereocenter - Diastereocontrol by Allylic Nitrogen (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 555-563 
    Details
    ISSN: 0009-2940
    Keywords: Kew Words: Asymmetric induction / Alcohols, homoallylic, diastereoselective synthesis of / γ-Amino alcohols, diastereoselective synthesis of / Hydrogen bonding / [2,3] Sigmatropic rearrangement / Wittig rearrangement ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The stereochemistry of Wittig-Still rearrangements under the influence of an allylic stereogenic center attached to Bn2N or RNBoc groups is studied. Rearrangements are subject to stereocontrol through asymmetric induction. Stannylated allyl ethers 13 with Z double bonds give syn-configuration amino alcohols 15 exclusively (ds 〉95 : 〈 5 - 〉 99.8 : 〈 0.2). Stannanes of E configuration 14 lead to 15 less selectively (syn :anti = 46 : 54 - 92 : 8). X-ray structural data are provided for amino alcohol syn-15b and for the bis(carbamate) 17.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230323
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    Hetero-π-Systeme, 181 Hochsubstituierte 2,4-Di-tert-butyl-1-boracyclohexadiene (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 505-511 
    Details
    ISSN: 0009-2940
    Keywords: Borabenzene / Sandwich complex / Steric crowding ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hetero π-Systems, la. - Highly Substituted 2,4-Di-tert-butyl-l-boracyclohexadienesBoracyclohexadiees 14 and 16 with three bulky groups should be ideal starting materials for the preparation of kinetically stabilized borabenzene derivatives. They are formed by substitution reactions of anion 11, which itself is derived from 2,4-di-tert-1-methoxy-1-bora-2,5-cyclohexadiene (10) by lithiation. Reaction of lithium compound 11 with ferrous chloride provides the sandwich-type complex 12. As shown by X-ray structure analysis, 12 has C2 symmetry with the boron atoms in a syn arrangement in staggered conformation, an unusal feature for borabenzene complexes. Exchange of the methoxy group in the trimethylsilylated substance 16 leads to compounds 18a, 18b, 18c, 18d. Pyrolyses of the various precursors are described.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230317
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    Synthese angularer Tetraquinane durch Photo-Thermo-Metathese diastereomerenreiner Benzochinon-Tetrahydropentalen-Addukte (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 549-554 
    Details
    ISSN: 0009-2940
    Keywords: Metathesis, photo-thermo / Tetraquinanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of Angularly Annulated Tetraquinanes by Photo-Thermo Metathesis of Diastereomerically Pure Adducts Between Benzoquinone and TetrahydropentalenesA retrosynthesis is presented for an angularly fused tetraquinane, the central step of which is the photo-thermo metathesis of a tetrahydropentalene - benzoquinone adduct. A sequence of Michael addition/condensation reaction gives the 3-methyl- l-phenyl-1,2-dihydropentalene (2) in 70% yield from benzalacetone and cyclopentadiene. Reaction with lithium aluminum hydride lead to a 1.0: 1.0:0.8 mixture of the 1,2,3,4-tetra-hydropentalenes 4a and 4b and the 1,2,3,5tetrahydropentalene 5. This reaction is highly diastereoselective (d.s. 〉 96%) and provides the cis compounds exclusively. Diels-Alder cycloadditon of 4a, b and 5 to benzoquinone also proceeds highly stereoselectively. The adducts 7a, b and 8 may be separated by fractional crystallization. Their relative configuration can be determined by means of 2D-COSY and NOE experiments. The endo arrangement is demonstrated by the photoreactivity of the cycloadducts. Gas-phase thermolysis (700°C/0.05 Torr) of the cage molecules 9a and 9b (from irradiation in benzene) gives the angularly annulated tetraquinanes 10a and 10b in 95 and 88% yield, respectively.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230322
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    Zur Reaktion des Diphosphenyl-Komplexes (η5-C5Me5)(CO)2Fe - P=P - Aryl (Aryl = 2,4,6-tBu3C6H2) mit elektronenarmen Alkenen. Röntgenstrukturanalyse des Diphosphetans (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 733-738 
    Details
    ISSN: 0009-2940
    Keywords: Diphosphene complexes / 1,2-Diphosphetanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transition-Metal-Substituted Diphosphenes, XVIII1). - On the Reactivity of the Diphosphenyl Complex (η5-C5Me5)(CO)2Fe - P=P - Aryl (Aryl = 2,4,6-tBu3C6H2) with Electron-Deficient Alkenes. X-ray Analysis of the Diphosphetane The transition-metal-substituted diphosphene (η5-C5Me5)(CO)2Fe - P=P - Aryl (1) reacts with fumarodinitrile (2a) to give the 1,2 diphosphetane all-trans- as the result of a [2 + 2] cycloaddition. Similarly, compound 1 is converted by either dimethyl fumarate (2b) or dimethyl maleate (2c) into the same cycloadduct all-trans- (3b). Diphosphetane 3a was completely characterized by a single-crystal X-ray analysis.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230414
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  • 77
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    Ein neuer Zugang zu enantiomerenreinen β-Lactamen aus α-Aminosäuren durch präparative Anwendung der Isonitril-Nitril-Umlagerung (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 635-638 
    Details
    ISSN: 0009-2940
    Keywords: β-Lactams / Isonitrile-nitrile rearrangement / α-Amino acids ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A New Approach to Enantiomerically Pure β-Lactams from a-Amino Acids by Applying the Isonitrile-Nitrile Rearrangement(S)-Phenylalanine (1) was converted into (S)-3-benzyl-2-azetidinone (8b) by a multistep reaction sequence. The key step of this approach is a stereospecific isonitrile-nitrile rearrangement (3 → 4) by flash pyrolysis, which may be performed in 20-g batches of 3. An improved procedure for the preparation of (S)-Phenylalaninol (2a) is described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230333
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  • 78
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    Masthead (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230401
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  • 79
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    Alkinverbrückte Vierkerncluster durch Expansion von Dreikernclustern (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 677-684 
    Details
    ISSN: 0009-2940
    Keywords: Cluster expansion/Clusters, alkyne-bridged tetranuclear/Framework isomerism ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Alkyne-Bridged Tetranuclear Clusters by Expansion of Trinuclear ClustersUnder photochemical activation Fe2(CO)9 is a suitable reagent for the expansion of alkyne-bridged trinuclear clusters 1-7 (Fe3, FeCo2, FeNi2, RuCo2, FeCoNi, RuCoNi, RuCoMo) to the corresponding tetranuclear clusters 9-15 containing Fe(CO)3 building blocks. The analogous incorporation of RhCp building blocks was possible by heating RhCp(CO)2 together with the alkyne-bridged Fe3, FeCo2, RuCo2, RuCoMo, and RuCoW clusters 1, 2a, 4, 7, and 8. The resulting clusters 16-20 with octahedral M4C2 frameworks showed framework isomerism in two cases [RuFeCo2 (11a, b) and RuCoMoRh (19a, b)]. Crystal structure determinations were performed for the Fe4 and Fe3Rh clusters 9, 16 as well as for both isomers 19a, b of the RuCoMoRh cluster.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230405
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  • 80
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    Wasserstoffübertragungen, 15 Zum Ablauf der Dehydrierung von Dihydroarenen durch Chinone (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 627-633 
    Details
    ISSN: 0009-2940
    Keywords: Hydrogen transfer / Dehydrogenation of dihydroarenes / Isotope effects / Quinones, dehydrogenation with chloranile ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hydrogen Transfer Reactions, 15lI. - On the Transition State in the Dehydrogenation of Dihydroarenes by QuinonesIn the hydride abstraction from 1,2-dihydronaphthalene by o-chloroanile the regioselectivity correlates with the stability of the carbenium ions as shown by both kinetic tests and reactions of isotopomeric hydrogen donators. - The temperature dependence of primary isotope effects does not correspond with any of the categories for the transition state as proposed by Kwart2). This was examined for 1,4-cyclohexadiene and 9,10-dihydroanthracene by a Bell correction and the parameters of activation (AH/AD und [ΔEA]D/H). A VAT mechanism3) is proposed to explain both these results and the large primary isotope effects.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230332
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  • 81
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    TiCl4/NaI - A Novel, Efficient Reagent for Mild Reduction of the N - O Bond in Amine N-Oxides and Nitrones (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 647-648 
    Details
    ISSN: 0009-2940
    Keywords: Titanium, low-valent / Amine N-oxides / Deoxygenation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Heteroaromatic N-oxides and nitrones were readily and selectively deoxygenated to the corresponding bases or imines in excellent yields with the TiCl4/NaI reagent system.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230336
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  • 82
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    Optical Resolution of [2,2]Paracyclophanes by High-Performance Liquid Chromatography on Tris(3,5-dimethylphenylcarbamates) of Celllulos and Amylose (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 841-845 
    Details
    ISSN: 0009-2940
    Keywords: Resolution, optical / Stationary phase, Chiral / Anylose carbamates / Celluslose carbamates / [3.2]Paracyclophanes, functionalized ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Optical resolution of 22 [2,2]paracyclophane derivatives was examined by high-performance liquid chromatography (HPLC) using tris(3,5-dimethylphenylcarbamates) of cellulose and amylose as chiral stationary phases. Most compounds were completely separated into enantiomers at least on one of the stationary phases. The preparation of hte new cyclophane derivatives 10, 11, 12, 14, 16, and 19 as wel as a new procedure for the synthesis of 4-fluoro-[2,2]paracyclophane (3) are described.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230432
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  • 83
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    Pentamakrocyclische Tris-Kronen. - Selektive Bindung von Kationen, Anionen und Neutralverbindungen (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 859-867 
    Details
    ISSN: 0009-2940
    Keywords: Crown compounds / Host-guest chemistry / Macropentacyclic compounds / Phanes / Supramolecular chemistry ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pentamacrocyclic Tris-Crown Hosts. - Selective Binding of Cationic, Anionic, and Neutral Guest CompoundsThe tris-crown host compounds 1-4 were synthesized for the first time. The X-ray crystal structures of 2 and of the 1:3 complex of 1 and KSCN were determined. Whereas in the free crown 2 a less well preorganized molecular cavity is encountered, in the complex of 1 with KSCN one potassium ion is bound to each crown ether unit. One of the three SCN- anions is situated in the interior of the cavity and in addition is disordered in such a way as to be bound to the K+ using partially the S atom of the SCN- ion. Organic guest molecules like 1,2-, 1,3-, 1,5-, 2,6-, and 2,7-naphthalenediol as well as β-naphthol in acidic water solution are bound selectively in the interior of the cavities of the host molecules 2 and 3, but not by 1 and 4, the cavities of which seem to be too small and too large, respectively. In contrast, the binding of α-naphthol and of smaller phenolic guest molecules like phenol, resorcinol, pyrocatechol, phloroglucinol, pyrogallol, and 1,2,4-trihydroxy-benzene with the host 1-4 is much less pronounced (1H- NMR highfield shifts).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230435
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  • 84
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    Radikalische Cyclisierung von Dienen, III Radikalische Cyclisierung von (R)-(-)-Carvon - Über den Einfluß von Charge-Transfer-Wechselwirkung auf den spezifischen Drehwert (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 901-905 
    Details
    ISSN: 0009-2940
    Keywords: Radical-type cyclisation / Bicyclo[3.2.]octan-3-one, enantiomerically pure / Charge-transfer interactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Radical-Type Cyclisation of Dienes, 111. - Radical-Type Cyclisation of (R)-( - )-Carvone - On the Influence of Charge- Transfer Interactions on the Optical RotationUnder the conditions of radical cyclisation, a 1:1 diastereomeric mixture of (1R,2S,5R,R)-(+)- (2a) and (1R.2S,5R,6S)-(+)-6-methoxy-2,6-dimethylbicyclo[3.2.1]octan-3-ones (2b) is obtained from (R)-(-)-carvone in 70% yield. the configuration fo 2a and 2b were confirmed by X-ray structure analyses of their hydrazones 2d and 2e. The regio- and stereoselectivity of the radical cyclisation of 1 to 2a and 2b are discussed. The high value of the specific rotation [-555] of 2d is traced back to charge-transfer interactions between the endo-standing methoxy group at C-6 as electron donor and the dinitrophenyl-hydrazone group as electron acceptor.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230441
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  • 85
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    Notizen / Notes Phosphorverbindungen ungewöhnlicher Koordination, 43 Hochfunktionalisierte λ3-Phosphinine aus 5,5-Dimethoxycyclopentadienen und einem kinetisch stabilisierten Phosphaalkin (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 935-937 
    Details
    ISSN: 0009-2940
    Keywords: Key Words: Phosphaalkines / Diels-Alder reaction / λ3-Phosphinines ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Phosphorus Compounds with Unusual Coordination, 43. - Highly Functionalized λ3-Phosphinines from 5,5-Dimethoxycyclopentadienes and Kinetically Stabilized Phosphaalkyne1,2,3,4-Tetrachloro-5,5-dimethoxycyclopentadiene (5) is transformed into the λ3-phosphinine 10 by reaction with the phosphaalkyne 6; the bicyclic compound 7 is assumed to be the intermediate of the process. In an analogous way the reaction 14 + 6 yields the isomeric λ3-phosphinines 15 and 17.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230445
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  • 86
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    “Tuning” CH/CC Bond-Activation Processes of Branched Amines by Choosing the Appropriate Gas-Phase Transition-Metal Ion (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 939-941 
    Details
    ISSN: 0009-2940
    Keywords: Key Words: Transition-metal ions / Bond activation, CH and CC / Tandem mass spectrometry / Amines, aliphatic ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mechanisms of the deceptively similar gas-phase chemistry of amine complexes RC(CH3)2CH2NH2/M+ (R = H, CH3 M = Fe, Co, Ni) are uncovered by the use of deuterium-labeled compounds. It is demonstrated that the details of CH/CC bond-activation reactions are strongly metal-ion-dependent, as is the product distribution itself.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230446
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  • 87
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    Ein Cyclobutadiencarboxylat als Hetero-1,3-dien bei Diels-Alder-Reaktionen mit 2H-Azirinen (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 927-933 
    Details
    ISSN: 0009-2940
    Keywords: Cyclobutadiene / [4 + 2] Cycloaddition / 2H-Azirine / Bridgehead olefins ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Antiaromatic Compounds, 26 - A Cyclobutadienecarboxylate as a Hetero-1,3-diene in Diels-Alder Reactions with 2H-AzirinesThe cyclobutadienecarboxylic ester 1 adds 2H-azirines (2a-1) to yield the oxaazatricyclic compounds 4a-f. Under thermolysis conditions cleavage of isobutylene and formation of tricyclic ketones occurs (4a, c-e → 7a-d). The Dear pyridone 11 arises from the photolysis of 7a. The structures of compounds 4b and 11 are confirmed by X-ray crystal structure analyses.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230444
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  • 88
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    Beiträge zur Chemie der Halogensilan-Addukte, 20. Hexakoordinierte Verbindungen von Trichlorsilanen. - Darstellung, Kristall-und Molekülstruktur von RSiCl3·bipy (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 945-951 
    Details
    ISSN: 0009-2940
    Keywords: Chlorosilanes ; hexacoordinated/Silicon complexes ; octahedral ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hexacoordinated Compounds of Trichlorosilanes. - Preparation, Crystal and Molecular Structure of BSiCl3·bipyThe octahedral Si complexes CHCl2SiCl3·bipy (1), CCl3SiCl3·bipy (2), and Cl3SiCCl2SiCl3·bipy (3) are obtained by the reaction of the respective trichlorosilanes and 2.2′-bipyridine (bipy). Their composition is independent of the initial ratio of the components. X-ray structure determinations show the Si atoms of all three complexes to be octahedrally coordinated with the substituted methyl groups in axial positions. The configurations represent structures of least steric hindrance assuming spheric substituents and demonstrate the usefulness of this structural model for solid compounds (in contrast possibly to dissolved compounds) even for substitutents deviating strongly from this assumption. Bond lengths and angles agree with the presence of hexacoordinated complexes. Deviations from expected values are interpreted in terms of considerable steric interactions. 3 represents a case of strongly hindered coordination requiring interesting steric adjustments.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230502
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    Metal Ion Binding by Amino Acids. Potassium Hydrogen L-Glutamate Monohydrate K(L-GluH)·H2O (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1001-1004 
    Details
    ISSN: 0009-2940
    Keywords: Amino acid complexes ; L-Glutamate complexes ; Hydrogen L-glutamate complexes ; Potassium hydrogen L-glutamate ; Hydrogen bonding ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title compound is obtained by neutralization of aqueous solutions of L-glutamic acid with potassium hydroxide, and crystallization from aqueous methanol. The compound shows a pH of 7 in water at ambient temperature and an optical rotation [α]20D of -4.30 (c = 3.0). In the crystal (orthorhombic, space group P212121) the potassium ion is in a distorted trigonal-prismatic environment of six oxygen atoms of four different amino acids and of the water molecule. No nitrogen coordination is observed. Through the bridging function of some of the α-carboxylate oxygen atoms (O1, O2) and through complexation of the metal through the γ-carboxylate groups (O3), a layer-coordination polymer, with strings of potassium ions running parallel, is formed. The layers are cross-linked by hydrogen bonds involving the ammonium and γ-carboxylate functions as well as the water molecule.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230512
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  • 90
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    Darstellung, Struktur und Stereoisomerie von 1,3-Di-tert-butyl-1,3,2,4-diazadistibetidinen (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 975-978 
    Details
    ISSN: 0009-2940
    Keywords: 1,3,2,4-Diazadistibetidines, 1,3-di-tert-butyl- ; Geometrical isomers ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis, Structure, and Stereoisomerism of 1,3-Di-tert-butyl-l,3,2,4-diazadistibetidinesStarting from 1,3-di-tert-butyl-2,4-dichloro-1,3,2,4-diazadistibetidine a series of 1,3,2,4-diazadistibetidines [R-SbN-ttBu]2 with R = OMe (2), OPh (3), OtBu (4), N(Tms)2 (5), P(Tms)2 (6), Me (7), and tBu (8) has been synthesized. The NMR spectra prove most of the reaction products to be mixtures of geometrical isomers. The structure of trans-tetra-tert-butyldiaza-distibetidine 8a was confirmed by X-ray structure determination.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19901230507
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    Synthese und Reaktionen von 2-Pyridylphosphan, 2-C5NH4-PH2 (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 989-993 
    Details
    ISSN: 0009-2940
    Keywords: Phosphane ; 2-pyridyl- ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Reactions of 2-Pyridylphosphane, 2—C5NH4-PH2By reduction of diethyl 2-pyridylphosphonate (1) with LiAlH4 2-pyridylphosphane (2) is accessible in ≍80% yield. H/D exchange experiments and acid/base exchange reactions between 2 and PhPHLi or Ph2PLi show (2) to be a stronger pH acid than PhPH2 and Ph2PH. Silylation of the lithium phosphides 2-C5NH4-PRLi (R — H, SiMe3) with Me3SiCl affords the corresponding silyl derivatives 2-C5NH4-PR2 with CH3I or CH2Cl2 yields the mono- or bidentate secondary phosphanes 2-C5NH4-PHMe (6) and 2-C5NH4PHCH2PH-2-C5H4N (5), respectively. On treatment of 2 with CH3I or HCl the pyridinium salts [(2-C5NH4R)PH2]+X- (R — H, Me; X= Cl, I) are formed. However, coordination of 2 to transition metals in low oxidation states occurs by the phosphorus atom. Addition of the PH bonds in 2 to the activated C—C double bonds in acrylic acid esters, mesityl oxide, cinnamnic acid esters, and dimethyl vinylphosphonate leads to chiral P,N hybrid ligands with functional groups in the alkyl side chain.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19901230510
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    Präorganisierte Bis-ethine: Molekulare π-Pinzetten? (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1097-1103 
    Details
    ISSN: 0009-2940
    Keywords: Bond formation, C-C ; Iron complexes ; Macrocycles ; Molecular tweezers ; Naphthalenophane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preorganized Bis-ethynes: Molecular π-Tweezers?1,8-Bis[(arylethynylphenyl)]naphthalenes of type V (e.g. 10, 11) and 1,8-bis[(arylethenylphenyl)]naphthalenes (6, 6a, 7, 7a) were synthesized for the first time. In contrast to the known 1,8-bis(arylethynyl)naphthalenes VI their “stereologs” 10 and 11 are thermally stabile. Yet they react with pentacarbonyliron to yield dinuclear transition metal complexes of the type 12, 13, i.e. a strained cyclophane macrocycle is formed by C-C bond formation. The X-ray analysis of the di-tert-butyl compound 11 shows that the peri substituents diverge, but with increasing distance from the naphthalene skeleton one of the arylethynyl units is bent to the opposite direction (Figure 2). The question whether the new molecular skeleton V can be viewed as molecular tweezers is discussed: as the hydrocarbons react irreversibly with transition metal carbonyls, they may rather be taken as “tweezers for single use”.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cber.19901230524
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    Synthese und Eigenschaften kalamitischer Flüssigkristalle aus desoxygenierten Kohlenhydrat-Derivaten (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1129-1135 
    Details
    ISSN: 0009-2940
    Keywords: Deoxy sugars ; Glycosyl cyanides ; Liquid crystals, chiral, thermotropic ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Properties of Calamitic Liquid Crystals from Deoxygenated Carbohydrate DerivativesTreatment of the L-arabino- and Llyxo-configurated glycals 1 and 7 with trimethylsily cyanide leads to the formation of the anomeric nitriles 2, 3 and 15, 17, respectively. The configurational assignments are based on hydrogenated products such as 6 or 8 and 10. Depending on the configurations of the olefinic nitril sugars, various hydrogenation results are observed using palladium/charcoal or the Wilkinson catalyst. Methanolysis provides the corresponding methyl esters. The preparation of liquid-crystalline derivatives follows the classical route. In comparing the properties of these saccharide-based liquid crystals with the corresponding cyclohexane derivatives, the dominant influence of the anomeric effect on the tendency for phase formation can be observed. Some of the novel derivatives show highly twisted cholesteric and wide blue phases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230528
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  • 94
    Electronic Resource
    Electronic Resource
    Photochemical Dehydrogenation, Ring Contraction, and Ring Expansion of Hydrogenated Derivatives of Benzoxazino-benzoxazine, Quinoxalino-quinoxaline, and Bibenzothiazole (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1149-1154 
    Details
    ISSN: 0009-2940
    Keywords: Photochemistry ; Benzoxazino-benzoxazines ; Quinoxalino-quinoxalines ; Bibenzothiazoles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The photochemical properties of the title compounds have been investigated and compared. The benzoxazino-benzoxazine derivatives 1 are photochemically converted into hydrogenated oxazole derivatives. In some cases this ring contraction is accompanied by a dehydrogenation reaction whereby the heterocyclic ring system becomes aromatic. Hydrogenated quinoxalino-quinoxalines also undergo a photodehydrogenation reaction and become aromatic. However, a ring contraction yielding the imidazolyl system does not take place. The only investigated sulfur-containing analog has different properties. The stable form is the bibenzothiazole 23 which contains a five-membered heterocyclic ring system. Photochemically 23 rearranges under ring expansion to give the benzothiazino-benzothiazine 24.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230531
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  • 95
    Electronic Resource
    Electronic Resource
    9,10-Phenanthrenocyaninatoeisen(II) (PhcFe) und axial koordinierte Isocyanid-Komplexe (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1105-1110 
    Details
    ISSN: 0009-2940
    Keywords: 9,10-Phenanthrenocyaninatoiron(II) ; Isocyanide complexes ; Porphyrin derivatives ; Semiconductors, organic ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 9,10-Phenanthrenocyaninatoiron(II) (PhcFe) and Axially Coordinated Isocyanide Complexes9,10-Phenanthrenocyaninatoiron(II) (PhcFe) is synthesized from 9,10-dicyanophenanthrene (3) and pentacarbonyliron. PhcFe exhibits similar spectroscopic properties (UV/VIS and Mößbauer spectra) and similar oxidation potentials as 1,2-Naphthalocyaninatoiron(II) (1,2-NcFe) and Phthalocyaninatoiron(II) (PcFe). Isocyanides RNC (R = tBu, cHx, Bzl, Me2Ph) react with PhcFe to form the corresponding bisaxially substituted 9,10-phenanthrenocyaninatoiron(II) compounds 4-7. Reaction of PhcFe with 1,4-diisocyanobenzene (dib) yields the bridged complex [PhcFe(dib)]n.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230525
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  • 96
    Electronic Resource
    Electronic Resource
    (E,Z) Equilibria, 12. Differential NMR Shielding by Phenyl, Assigned from Chemical Labelling and (Z,E) Equilibration (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1137-1141 
    Details
    ISSN: 0009-2940
    Keywords: Allyl anion ; Differential NMR-shielding ; Schiff's bases ; Stereoselective substitution ; Isomerization, (Z,E) ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Unequivocal NMR assignments of the (E,Z) isomeric pairs 3 and 8 are possible by (Z,E) equilibration. Deprotonation of 2-methyl-1-phenylpropene (1) with n-BuLi under any conditions gives only a single allyl-metal derivative 2. Methylation of the latter gives the isomer (Z)-3, while deuteriolysis leads to the isotopically labelled derivative 6 of the olefin 1; this Proves the NMR assignments for 1 as well as the endo configuration of 2. The phenyl group gives rise to a differential shielding effect on the γ-carbon nuclei in methyl and methylene gropus along a CC double bond (ca, 7 ppm), and this effect is comparable to that along a CN double bond as in 8. The nitrile function in 5c is much less effective.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230529
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  • 97
    Electronic Resource
    Electronic Resource
    Künstliche molekulare Anion-Wirte. Die Synthese eines chiralen bicyclischen Guanidinium-Salzes als funktionalisierte Ankergruppe für Oxo-Anionen (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 907-915 
    Details
    ISSN: 0009-2940
    Keywords: Molecular recognition / Anion host compound / Guanidmiun salt / Chiral synthesis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Artificial Molecular Anion Hosts. Synthesis of a Chiral Bicyclic Guanidinium Salt Serving as a Functionalized Anchor Group for 0x0 AnionsStarting from 1-asparagine, the synthesis of the S,S-bis(hydroxymethyl)-substituted bicyclic guanidinium salt 3 is described, which is obtained in 20% overall yield with a diastereomeric excess de 〉 98%. The guanidinium compound 3 may serve as a binding module in the enantioselective recognition of oxo anions in polytopic abiotic receptors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230442
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  • 98
    Electronic Resource
    Electronic Resource
    Masthead (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990) 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230501
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  • 99
    Electronic Resource
    Electronic Resource
    Diphosphinonitrenium and -phosphenium Cations, Jahn-Teller Distorted Allyl Systems (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 971-973 
    Details
    ISSN: 0009-2940
    Keywords: Calculations ; Jahn-Teller distortion ; Nitrenium ; Phosphenium ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ab initio calculations at SCF, MCSCF, and ACPF level were performed on a series of the phosphenium- and nitreniumcation family. These show that they possess an allylic π-system with 4 electrons, which is distorted from planarity when the terminal groups of the allylic system are PR2 (R — H) fragments. The distortion is such as to adopt C2 symmetry, and is the consequence of Jahn-Teller distortion via mixing of the energy highest π2 orbital with an energetically low lying δ* orbital. The latter interaction is only operative if a symmetry breaking from C2v to C2 symmetry occurs. The importance of Jahn-Teller distortion on the biradical character in these systems is investigated by correlation calculations.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230506
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  • 100
    Electronic Resource
    Electronic Resource
    Lineare Oligophosphaalkane, XXV. Synthese von Ph2P—CH2—PH2 und (ph2P—CH2)2PH durch Phosphinomethylierung von PH3 unter Phasentransferkatalyse (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 995-999 
    Details
    ISSN: 0009-2940
    Keywords: Phosphine ; Phosphinomethylation ; Phase-transfer catalysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Linear Oligophosphaalkanes, XXV1. - Synthesis of Ph2P—CH2—PH2 and (Ph2P—CH2)2PH by Phosphinomethylation of PH3 with Phase-Transfer CatalysisAlkylation of Ph2PH with CH2Cl2 under phase-transfer conditions in the system dichloromethane/toluene/water affords Ph2P-CH2Cl in high yields. Depending on the reaction conditions employed Ph2P-CH2Cl reacts with PH3 in the two phase system under phase-transfer catalysis (nBu4NCl) to yield the tertiary-primary methylenebis(phosphane) Ph2P-CH2-Ph2 (2) or the PH functional triphosphaalkane Ph2P-CH2-PH-CH2-PPh2 (3), respectively. Metallation of 2 and 3 with RLi (R = nBu, tBu) and subsequent reaction with Me3siCl yields the silyl derivatives 2e and 3b, respectively. The analysis of the 1H- 13C- and 31P-NMR spectra is reported.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230511
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