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  • Digitale Medien  (28.665)
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  • 1995-1999  (9.535)
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  • Digitale Medien  (28.665)
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  • 101
    Digitale Medien
    Digitale Medien
    Immunocytochemical demonstration of oncocytes in normal adenohypophysis (1999)
    Springer
    Acta neuropathologica 97 (1999), S. 40-44 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Key words Pituitary gland ; Immunohistochemistry ; Mitochondria ; Oncocytes ; Oncocytomas
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Immunocytochemical examination for mitochondrial protein and cytochrome oxidase was performed to demonstrate oncocytes in normal adenohypophysis obtained from 28 patients of various age. A small number of solitary large epithelial cells showed intense cytoplasmic granular immunoreactivities for mitochondrial protein and cytochrome oxidase. The proportions of the cells positive for the former and the latter ranged from 0% to 5.9% (mean ± SD; 1.5 ± 1.7%) and from 0% to 4.9% (1.4 ± 1.6%), respectively. These cells were either absent or extremely rare in young patients (under 10 years) but tended to increase in number with age (P 〈 0.0001). On the other hand, the mirror section technique showed that most of these cells were negative for adenohypophysial hormones, but a few of them were faintly positive for: α-subunit (8.0%), β-subunits of follicle-stimulating hormone (4.8%), luteinizing hormone (2.5%), thyroid-stimulating hormone (1.0%), and growth hormone (0.5%), and were negative for prolactin and adrenocorticotropic hormone. We considered that these cells represent oncocytes that exist in varying numbers in normal adenohypophysis. It was suggested that oncocytes in normal adenohypophysis share various common features with tumorous oncocytes of pituitary oncocytomas.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004010050953
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  • 102
    Digitale Medien
    Digitale Medien
    A comparison of cell phenotypes in hemimegalencephaly and tuberous sclerosis (1999)
    Springer
    Acta neuropathologica 98 (1999), S. 407-413 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Key words Hemimegalencephaly ; Tuberous sclerosis ; Large neurons ; Balloon cells ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Hemimegalencephaly, an uncommon sporadic nonfamilial congenital dysplastic abnormality of the central nervous system, constitutes a pathological spectrum of neuronal migration disorders, but consistently includes abnormal large neurons similar to those in the cortical tubers of tuberous sclerosis. Microscopically, there are also cells with homogeneous and weakly eosinophilic cytoplasm with a single eccentric nucleus, sometimes called balloon cells (likewise prominent in tuberous sclerosis). We looked for immunohistochemical and ultrastructural differences in the large neurons and balloon cells between hemimegalencephaly and tuberous sclerosis. Microtubule-associated protein 1B and 2, phosphorylated and non-phosphorylated neurofilament and synaptophysin identify the large neurons and distinguish them from balloon cells in both entities. Balloon cells in hemimegalencephaly showed no immunoreactivity for TSC2 gene product, tuberin, and vimentin, but similar cells in tuber tissue showed consistent immunoreactivity. Balloon cells in hemimegalencephaly showed no immunoreactivity for glial fibrillary acidic protein, but some cells in tubers showed such immunoreactivity. Ultrastructurally, balloon cells in hemimegalencephaly contained very few lysosomes, microfilaments, and microtubules, but abundant lipofuscin granules. Similar cells in tubers had prominent lysosomes, more microfilaments and microtubules, and very few lipofuscin granules. The resemblance between abnormal cells in hemimegalencephaly and tuberous sclerosis is superficial; their immunohistochemistry and electron microscopic profiles show distinct differences.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004010051101
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  • 103
    Digitale Medien
    Digitale Medien
    Inducible nitric oxide synthase expression in human cerebral infarcts (1999)
    Springer
    Acta neuropathologica 97 (1999), S. 215-220 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Key words Cerebral ischemia ; Inflammation ; Immunohistochemistry ; Nitrotyrosine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The inducible or “immunological” isoform of nitric oxide synthase (iNOS) is induced in many cell types by inflammatory stimuli and synthesizes toxic amounts of NO. In rodent models of focal cerebral ischemia, iNOS is expressed in neutrophils invading the injured brain and in local blood vessels. Studies with iNOS inhibitors and iNOS null mice indicate that NO produced by iNOS contributes to ischemic brain injury. In the present study, we sought to determine whether iNOS is also expressed in the human brain after ischemic stroke. Studies were conducted using immunohistochemistry on autopsy brains with neuropathological evidence of acute cerebral infarction. iNOS immunoreactivity was observed in neutrophils infiltrating the ischemic brain and in blood vessels within the ischemic territory. iNOS-positive cells also were immunoreactive for nitrotyrosine, reflecting protein nitration by NO-derived peroxynitrite and nitrites. iNOS or nitrotyrosine immunoreactivity was not detected outside the region of the infarct. These observations provide evidence that iNOS is expressed in the human brain after ischemic infarction and support the hypothesis that iNOS inhibitors may be useful in the treatment of ischemic stroke in humans.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004010050977
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  • 104
    Digitale Medien
    Digitale Medien
    Advanced glycation endproducts are deposited in neuronal hyaline inclusions: a study on familial amyotrophic lateral sclerosis with superoxide dismutase-1 mutation (1999)
    Springer
    Acta neuropathologica 97 (1999), S. 240-246 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Key words Amyotrophic lateral sclerosis ; Advanced glycation endproducts ; Immunohistochemistry ; Superoxide dismutase ; Hyaline inclusions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract To determine the role of advanced glycation endproducts (AGE) in the pathogenesis of familial amyotrophic lateral sclerosis (ALS) with superoxide dismutase-1 (SOD1) mutation, we investigated the immunohistochemical localization of N ɛ-carboxymethyl-lysine (CML), one of the major AGE structures, in spinal cords from three familial ALS patients with a heterozygous Ala to Val substitution at codon 4 in the gene for SOD1. Neuronal hyaline inclusions (NHIs), the abnormal structures seen in some of the remaining lower motor neurons of familial ALS patients with SOD1 mutation, were intensely stained by a monoclonal antibody specific for CML in contrast to the only weakly stained cytoplasm. Immunoelectron microscopy depicted the CML determinants restricted to the granule-associated thick linear structures that mainly compose the NHIs. The NHIs were also recognized by antibodies to SOD1, phosphorylated neurofilament protein and ubiquitin. No focal collection of either CML or SOD1 was found in neurons of the control individuals. Our results indicate that CML is a component of the NHIs of familial ALS patients with SOD1 mutation, and suggest that the CML formation may be mediated by protein glycoxidation or lipid peroxidation in the presence of oxidative stress from mutant SOD1, in association with motor neuron degeneration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004010050980
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  • 105
    Digitale Medien
    Digitale Medien
    Immunoreactivity of β-amyloid precursor protein in amyotrophic lateral sclerosis (1999)
    Springer
    Acta neuropathologica 97 (1999), S. 463-468 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Key words Amyotrophic lateral sclerosis ; β-Amyloid precursor protein ; Immunohistochemistry ; Fast axonal transport ; Anterior horn neuron
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We investigated the localization and extent of β-amyloid precursor protein (β-APP695) immunoreactivity as a sensitive marker for impairment of fast axonal transport in the spinal cords of 21 patients with amyotrophic lateral sclerosis (ALS), paying special attention to anterior horn neurons. Specimens from 18 patients without neurological disease served as controls. Increased β-APP immunoreactivity was frequently recognized in the anterior horns of the ALS patients with short clinical courses or with mild depletion of anterior horn cells, while no β-APP immunoreactivity was demonstrated in those with severe depletion of anterior horn neurons or with long-standing clinical courses. Increased β-APP immunoreactivity in the anterior horn neurons was mainly confined to the perikarya and no immunoreactivity was recognized in the dendrites or proximal axons directly emanating from the somata, except some spheroids (proximal axonal swellings) which showed increased immunoreactivity of β-APP. Increased β-APP immunoreactivity was spotted or focally aggregated in the perikarya of normal-looking large anterior horn neurons, while it was frequently diffuse in that of degenerative neurons such as central chromatolytic cells and or those with simple atrophy. On the other hand, the controls showed no immunostaining with β-APP in the spinal cord. These findings suggest that increased immunoreactivity of β-APP in neuronal perikarya of the anterior horn cells and in some proximal axonal swellings is an early change of ALS, and may be a response of the increased synthesis of β-APP resulting from neuronal damage, or the impairment of fast axonal transport.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004010051015
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  • 106
    Digitale Medien
    Digitale Medien
    Correlation of survival time with size of axonal swellings in diffuse axonal injury (1999)
    Springer
    Acta neuropathologica 98 (1999), S. 197-202 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Key words Diffuse axonal injury ; Head injury ; β-amyloid precursor protein ; Immunohistochemistry ; Forensic neuropathology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Widespread damage to axons in the white matter of the brain is a well-recognised consequence of non-missile head injury. This diffuse axonal injury is characterised by a gradual swelling of the axon associated with an accumulation of cellular organelles and proteins. We have investigated the relationship between the size of the swellings of the damaged axon with survival time in post-mortem brain tissue. Sixty-six cases of head injury with known length of post-traumatic survival were selected for study, and immunohistochemistry for β-amyloid precursor protein (βAPP) was carried out. The minimum diameter of the βAPP-immunolabelled damaged axons was measured in micrometers using the IBAS image analysis system. There was a strong, positive and significant relationship between the mean size of axonal swelling and survival time which plateaued at around 85 h post injury. With longer survival times the situation becomes more complex. βAPP immunolabelling of damaged axons can contribute evidence about trauma and post-injury survival time in the forensic setting but should always be assessed with other evidence.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004010051069
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  • 107
    Digitale Medien
    Digitale Medien
    Patterns of cyclooxygenase-1 and -2 expression in human gliomas in vivo (1999)
    Springer
    Acta neuropathologica 98 (1999), S. 240-244 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Key words Glioma ; Cyclooxygenase ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Cyclooxygenases (COX, prostaglandin endoperoxide synthases, PGG/H synthases) are potent mediators of inflammation. While COX-1 is constitutively expressed in a wide range of tissues, COX-2 is cytokine inducible. Although COX-1 expression is observed in normal tissue, enhanced COX-2 expression has been attributed a key role in the development of edema, impeding blood flow and immunomodulation observed in pathologically altered tissues. Here, we have analyzed the expression of COX-1 and COX-2 in 50 gliomas and 10 control brains with no neuropathological alterations by immunohistochemistry; 22 glioblastoma multiforme, 9 anaplastic astrocytomas, 5 protoplasmic astrocytomas, 1 gemistocytic astrocytoma and 13 fibrillary astrocytomas were included in the study. Compared with control brains, accumulation of COX-1 was detected in 20–50% of all cells in both low- and high-grade gliomas. Double-labeling experiments revealed COX-1 expression in subsets of macrophages/ microglial cells within the tumor parenchyma and in areas of infiltrative tumor growth. Of the COX-1-positive cells, 90% expressed MHC class II antigens. No COX-1 immunoreactivity was observed in tumor cells. COX-2-positive cells accumulated in tumor cells and in single macrophages/microglial cells in the immediate vicinity of necroses. Further studies are required to determine whether COX-2 is involved in the development of necrosis or, more likely, whether COX-2 is a part of the tumor tissue response to necrosis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004010051075
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  • 108
    Digitale Medien
    Digitale Medien
    Immunohistochemical evaluation of the marbled state in childhood hypoxic encephalopathy (1999)
    Springer
    Acta neuropathologica 98 (1999), S. 257-261 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Key words Calcium-binding protein ; Enkephalin ; Hypoxic encephalopathy ; Immunohistochemistry ; Marbled state
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We have immunohistochemically analyzed the marbled state in 8 cases of perinatal hypoxic ischemic encephalopathy and 4 cases of infantile hypoxic encephalopathy, using antibodies against calbindin-D28k (CaBD), glial fibrillary acidic protein (GFAP), methionine-enkephalin (MEnk), myelin basic protein (MBP), neurofilament (NF), parvalbumin (PV), substance-P (SuP) and synaptophysin (SP). The marbled state was found in the thalamus in 11 cases, whose age at death was over 10 years. Four cases demonstrated the marbled state in the cerebral cortex, in addition to the striatum and/or the thalamus. The abnormally myelinated fibers in the marbled state were stained with both Klüver-Barrera and Holzer stainings; however, they were partly immunopositive for MBP and completely immunonegative for GFAP, CaBD, MEnk, PV, SuP and SP, although some of the neurons and/or fibers showed immunoreactivities for those calcium-binding proteins and/or neurotransmitters. The axons were visualized in the abnormally myelinated fibers by Bodian staining and/or anti-NF immunostainings in the cerebral cortex and striatum but not in the thalamus. GFAP-positive astrocytes did not show any continuity with the abnormally myelinated fibers. These histological features were seen in the cerebral cortex, striatum and thalamus. Difference of the etiology did not affect the histological features with the exception of anti-PV staining, in which PV-immunopositive neurons were observed only in aged subjects with infantile hypoxic encephalopathy, and seemed to be more severely affected by hypoxic stress during the perinatal period than the early infantile period. These data suggest that the site of lesion or the length of survival period after brain injury might influence the formation of the marbled state rather than the etiology. And the direct relationship between the abnormally myelinated fiber and astrocytic process was not verified.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004010051078
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  • 109
    Digitale Medien
    Digitale Medien
    Nebulin is normally expressed in nemaline myopathy (1999)
    Springer
    Acta neuropathologica 97 (1999), S. 433-436 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Key words Congenital nemaline myopathy ; Nebulin ; α-Actinin ; Immunohistochemistry ; Western blot
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Since the nebulin gene is located in the candidate gene locus of autosomal recessive nemaline myopathy, 2q21.2–q22, we examined five muscle biopsy specimens with monoclonal and polyclonal antibodies against nebulin in combination with the modified Gomori trichrome stain. We were able to demonstrate immunohistochemically that there was no abnormality in nebulin in the muscle fibers both with and without nemaline bodies. Although the molecular weight of nebulin was normal, it was slightly reduced in amount on immunoblotting.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004010051011
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  • 110
    Digitale Medien
    Digitale Medien
    Extracellular matrix and development of lamination in the dorsal lateral geniculate nucleus in the tree shrew (Tupaia belangeri) (1999)
    Springer
    Anatomy and embryology 199 (1999), S. 549-561 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Key words Visual system ; Immunohistochemistry ; In situ hybridization ; PNA ; Tenascin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  In the tree shrew (Tupaia belangeri), the cytoarchitectonic lamination of the lateral geniculate nucleus cannot be detected at birth; it only appears during the early postnatal period. However, a laminated pattern was revealed with rapid Golgi staining and retinal afferents were segregated into the appropriate laminae well before cytoarchitectonic lamination could be seen. Both observations indicate that the extracellular matrix may play a role in the separation of lateral geniculate nucleus cells into laminae. In the present study, the organization of the extracellular matrix was investigated during development using immunohistochemical and in situ hybridization techniques. For immunohistochemistry, peanut agglutinin (PNA) lectin and antibodies against tenascin (TN) were chosen, while for in situ hybridization, mTN riboprobes were used, simultaneously, with antibodies against Vimentin (Vim) and microtubule associated protein (MAP-2). The results showed that the pattern of PNA-binding glycoproteins and that of tenascin were relatively similar, although tenascin appeared later and disappeared earlier. The first interlaminar spaces to be detected were those between layers innervated by opposite eyes. The TN specific mRNA was detected in the lateral geniculate nucleus at P0, but was no longer visible at P7. By comparing TN mRNA and Vim or MAP-2 stainings a correspondence could be observed. The extracellular matrix lamination therefore seems to precede cytoarchitectonic lamination, suggesting that the extracellular matrix may play a role in the development of laminated structures. The TN-producing cells seem to be developing astrocytes and neurons.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004290050252
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  • 111
    Digitale Medien
    Digitale Medien
    Cyclooxygenase-2 immunoreactivity in the human brain following cerebral ischemia (1999)
    Springer
    Acta neuropathologica 98 (1999), S. 9-14 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Key words Prostaglandin H2 synthase ; Stroke ; Inflammation ; Immunohistochemistry ; Prostaglandins
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The prostaglandin synthesizing enzyme cyclooxygenase-2 (COX-2) is up-regulated in the brain of rodents during cerebral ischemia and contributes to ischemic brain injury. This study sought to determine whether COX-2 is also up-regulated in the human brain in the acute stages of cerebral ischemic infarction. Paraffin-embedded sections from patients who died 1–2 days following infarction in the middle cerebral artery territory were processed for COX-2 immunohistochemistry. COX-2 immunoreactivity was observed in infiltrating neutrophils, in vascular cells and in neurons located at the border of the infarct. The data suggest that COX-2 up-regulation is also relevant to cerebral ischemia in humans and raise the possibility that COX-2 reaction products participate in the mechanisms of ischemic injury also in the human brain.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004010051045
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  • 112
    Digitale Medien
    Digitale Medien
    Variable histological expression of dystrophinopathy in two females (1999)
    Springer
    Acta neuropathologica 97 (1999), S. 657-660 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Key words Xp21 muscular dystrophy carriers ; Muscle biopsy ; Immunohistochemistry ; X chromosome ; inactivation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We report two carriers of Xp21 muscular dystrophy with unusual clinical manifestations and striking variability of dystrophin deficiency within the same muscle biopsy. The first patient was a 60-year-old nun with recent onset of cramps and proximal weakness, mimicking an acquired myopathy. Muscle biopsy disclosed slight alterations in one sample and severe dystrophic changes in another; dystrophin was absent in 7% fibers in the former specimen and in 60% in the second. X inactivation was skewed with 90% cells inactivating the same X chromosome. The second patient was a 17-year-old girl with hyperCKemia, learning disability and a family history of X-linked muscular dystrophy. Muscle biopsy displayed slight fiber size variability and some internal nuclei; dystrophin was absent only in one muscle fiber. A second sample with the same morphological features demonstrated dystrophin deficiency with mosaic distribution. The pattern of X inactivation was normal. These cases emphasize the variability of histopathological changes and dystrophin deficiency in Xp21 muscular dystrophy carriers and the risk of sampling errors in muscle biopsy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004010051043
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  • 113
    Digitale Medien
    Digitale Medien
    Immunohistochemical, conventional and immunoelectron microscopical characteristics of periodic acid-Schiff-positive granules in the mouse brain (1999)
    Springer
    Acta neuropathologica 98 (1999), S. 31-38 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Key words Polyglucosan body ; Periodic ; acid-Schiff-positive granules ; Mouse brain ; Immunohistochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Periodic acid-Schiff-positive granules (PGs) appear in the mouse brains in relation to advancing age. The exact location and pathophysiological significance of PGs, however, are not fully understood. The incidence, staining properties, and topographical distributions of PGs in the brains of 17 AKR mice ranging in age from 7 to 18 months were examined histochemically and immunohistochemically using antibody KM279 raised against a polyglucosan. In addition, to define the precise site of PG formation, we investigated the brains of 4 AKR mice of 24 months of age using conventional and immunoelectron microscopy. PGs were seen in all mice examined and the levels were increased with age. The PGs were located predominantly in the hippocampus and, to a lesser extent, in the cerebellum and olfactory bulb. Immunohistochemically, PGs in the hippocampus and cerebellum were labeled uniformly with KM279. On immunoelectron microscopy with this monoclonal antibody, the fibrillar or membranous structures corresponding to PGs seen using light microscopy were labeled specifically with gold particles. With conventional electron microscopy, fibrillar or membranous structures were seen along with synaptic vesicles and dense-core granules. Moreover, around the cells containing PGs, a few synaptic junctions with neighboring cells were observed, indicating that the cells contributing to formation of PGs were neuronal cells. The positive immunoreactivity of AKR mouse PGs for the antibody KM279 suggests that the PGs and similar structures in other species may share a common antigenicity. Thus, it is assumed that PGs in AKR mice might result from some abnormalities in glucose metabolism.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004010051048
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  • 114
    Digitale Medien
    Digitale Medien
    Glial expression of presenilin epitopes in human brain with cerebral infarction and in astrocytoma (1999)
    Springer
    Acta neuropathologica 98 (1999), S. 337-340 
    Details
    ISSN: 1432-0533
    Schlagwort(e): Key words Presenilin ; Cerebral infarction ; Astrocytoma ; Glial cells ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Presenilins, some gene mutations of which are associated with familial Alzheimer’s disease (AD), are expressed mainly in neurons in normal brains and brains from patients clinicopathologically diagnosed as AD. They are thought to be related to cell death and survival. We studied the immunolocalization of presenilin to investigate its possible relation to cell death and glial proliferation, using two antibodies against different portions of the presenilin 1 protein, in human brains with cerebral infarction and in astrocytoma, where abundant cell death and glial proliferation are present. Expression of presenilin epitopes was more marked in glial cells than in neurons in and around the ischemic focus, and it was also robust in astrocytoma cells. These findings suggest that presenilins are functioning not only in neurons but also in glial cells in reactive and neoplastic proliferation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004010051090
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  • 115
    Digitale Medien
    Digitale Medien
    Distribution of cytokeratin filaments and vimentin in developing human taste buds (1999)
    Springer
    Anatomy and embryology 199 (1999), S. 291-299 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Key words Gustatory papillae ; Embryonic development ; Fetal development ; Immunohistochemistry ; Innervation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Taste buds in humans originate from approximately the 8th postovulatory week under the influence of ingrowing nerve fibers. Since they develop from local epithelium, it is of interest whether or not prospective taste cells maintain or develop characteristics of epithelial cells that are different from those of the adjacent epithelium during differentiation. The aim of this study was to monitor changes of the distribution of the cytokeratin filaments (CKs) 8, 18, 19 and 20 (”gastrointestinal” type), CK 7 (”ductal” type), and CK 13 (maturation ”mucosa type”), as well as vimentin in developing human taste buds and adjacent squamous epithelium. With the exception of CK13, which remains negative in taste bud anlagen and adult taste buds, all cytokeratins tested were present in taste cells. With the progress of development, the distribution of CKs becomes more and more restricted to taste cells and salivatory ducts as well as Ebner gland cells. Only CK20 is exclusively specific to taste bud anlagen and sometimes to individual bipolar cells occurring in early stages (week 8–9). Vimentin was located mainly in mesodermal derivatives but also in perigemmal epithelial cells during all stages of development. The occurrence of vimentin in ”borderline” epithelia that interface with underlying connective tissue, i.e., in a region of discontinuity, may be associated with particular events in development, cell migration or even dedifferentiation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004290050229
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  • 116
    Digitale Medien
    Digitale Medien
    Determinants of melanocyte density in adult human skin (1999)
    Springer
    Archives of dermatological research 291 (1999), S. 511-516 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Key words Melanocyte ; Naevus ; Melanoma ; Immunohistochemistry ; Monoclonal antibody
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The distribution of melanocytes in human skin has been observed to vary within and among individuals, yet little is known of the factors that determine the density of these pigment cells. These factors were explored in a molecular epidemiological study conducted among a population-based sample of 97 male subjects aged over 50 years in Queensland, Australia. Information relating to environmental and phenotypic factors was collected through face-to-face interviews and physical examination of all participants. In addition, 2-mm biopsies of representative skin were taken from the dorsum of the hand and another anatomical site. Melanocytes were identified by cytoplasmic staining with the B8G3 (anti-TRP1) monoclonal antibody using standard immunohistochemical techniques. Melanocyte counts were performed blind by two observers. On crude analysis, melanocyte density decreased with advancing age (P = 0.0002), and increased with increasing number of naevi (P = 0.01). Other pigmentary characteristics (such as hair and eye colour and depth of tan) were not associated with epidermal melanocyte density. Melanocyte density varied significantly by anatomical site (P = 0.02), with highest densities observed on the back/shoulders (n = 50, 17.1 ± 8.8 cells/mm, mean ± SD) followed by the upper limbs (n = 11, 12.6 ± 8.8 cells/mm) and lower limbs (n = 14, 14.4 ± 5.9 cells/mm). Lowest melanocyte densities were recorded on the anterior trunk (n = 3, 3.2 ± 2.4 cells/mm). These findings confirm the results of earlier studies in which site-specific differences in melanocyte density have been found. We speculate that the unequal distribution of melanocytes may partially explain the site-specific incidence of melanoma, offering fresh perspectives on the aetiology of this cancer.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004030050446
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  • 117
    Digitale Medien
    Digitale Medien
    Stratum corneum chymotryptic enzyme in psoriasis (1999)
    Springer
    Archives of dermatological research 291 (1999), S. 195-200 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Key words Epidermis ; Immunohistochemistry ; Protease ; Psoriasis ; Stratum corneum chymotryptic ; enzyme
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Stratum corneum chymotryptic enzyme (SCCE) is a serine protease which may function in the turnover of the stratum corneum by means of degradation of intercellular adhesive structures between corneocytes. It is also potentially an epidermal activating enzyme for cytokines such as interleukin-1β. The aim of this work was to study the expression of SCCE in psoriatic epidermis by means of immunohistochemistry, and to elucidate the nature of the SCCE present in psoriatic scales by means of biochemical analyses. In comparison to normal skin the number of cell layers expressing SCCE in psoriatic lesions was consistently increased. In nonlesional psoriatic skin the pattern of SCCE expression varied. It was similar to the pattern in normal skin in some biopsies, whereas in other biopsies evidence of an increased expression of SCCE was found. By means of zymography and immunoblotting, extracts of psoriatic scales were found to contain active SCCE as well as enzymatically inactive SCCE precursor. Also the effects of inhibitors on the activity towards a chromogenic protease substrate in the extracts after partial purification by gel exclusion chromatography were compatible with the presence of enzymatically active SCCE. We conclude that the expression of SCCE in psoriasis may be upregulated, and that the conversion of inactive SCCE-precursor to active SCCE occurs in the psoriatic lesion. The possible role of SCCE in the pathophysiology of psoriasis remains to be elucidated, but should be considered in future studies.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004030050393
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  • 118
    Digitale Medien
    Digitale Medien
    Immunohistochemical localization of the neutral cysteine protease bleomycin hydrolase in human skin (1999)
    Springer
    Archives of dermatological research 291 (1999), S. 238-240 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Key words Cysteine protease ; Bleomycin hydrolase ; Keratinocyte ; Skin cancers ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004030050400
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  • 119
    Digitale Medien
    Digitale Medien
    Serotonin in human allergic contact dermatitis. An immunohistochemical and high-performance liquid chromatographic study (1999)
    Springer
    Archives of dermatological research 291 (1999), S. 269-274 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Key words Serotonin ; Allergic contact dermatitis ; Immunohistochemistry ; High-performance liquid ; chromatography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Allergic contact dermatitis (ACD) is a common clinical condition leading to considerable morbidity. We have recently demonstrated that ketanserin, a serotonin antagonist, significantly inhibits nickel sulphate-induced ACD. Furthermore, serotonin-immunoreactive (IR) cells have previously been demonstrated in normal human cutaneous melanocytes. To further elucidate the role of serotonin in cutaneous contact hypersensitivity, we compared ACD involved skin and uninvolved skin from nickel-allergic patients, and normal skin from healthy volunteers, for the presence of serotonin-like immunoreactive cells using immunohistochemistry. In addition, serotonin concentrations in ACD involved and uninvolved skin were compared by high-performance liquid chromatography (HPLC). In the skin of normal healthy volunteers, the serotonin-IR cells were situated in the basal layer of the epidermis. In uninvolved skin the cells were also situated in the basal layer, but they were more numerous and the immunofluorescence intensity was greater. In involved skin, the IR cells were fewer and they were found higher up in the epidermis. Also, the configuration of these cells was different: they showed enlarged and elongated dendrites as well as dendritic spines. The serotonin antiserum-labelled cells in ACD involved skin were also NKI-beteb positive (the latter is known as a reliable marker of melanocytes). The concentration of serotonin in involved skin was significantly higher than that in uninvolved skin in ACD patients (P 〈 0.05). Taken together, our previous and present results indicate that serotonin plays an important role in ACD. The basal epidermal serotonin-IR cells are more dendritic in ACD, and are found more superficial in the epidermis, where they might release their content of serotonin, thereby influencing the inflammatory process.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004030050407
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  • 120
    Digitale Medien
    Digitale Medien
    Langerhans cells enclosing sunburn cells in acute UV erythema in vivo (1999)
    Springer
    Archives of dermatological research 291 (1999), S. 303-305 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Key words Langerhans cells ; Sunburn cells ; UV ; erythema ; Apoptosis ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004030050413
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  • 121
    Digitale Medien
    Digitale Medien
    The role of polymorphonuclear leukocyte infiltration in herpes simplex virus infection of murine skin (1999)
    Springer
    Archives of dermatological research 291 (1999), S. 28-36 
    Details
    ISSN: 1432-069X
    Schlagwort(e): Key words Herpes simplex virus ; Cutaneous infection ; Immunohistochemistry ; Polymorphonuclear leukocyte ; Anti-PMN antibody
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We undertook the present study to investigate the role of polymorphonuclear leukocytes (PMN) in defending skin against herpes simplex virus (HSV) infection. For this purpose, we established a mouse model of cutaneous HSV infection. The hind limb footpad skin of 4-week-old ICR mice was abraded linearly once with a feather edge file and infected with various strains of HSV with different virulence. In uninfected control mice, PMN appeared at the abraded skin lesion within 24 h, and were eliminated from the epidermis after 3 days. Mice inducted with a highly virulent strain of HSV demonstrated wide and severe erythematous lesions of the footpad skin and histologically, virus antigen-positive ballooning degenerated keratinocytes were observed. However, in infections with attenuated strains of HSV, the epidermis was regenerated and a viral antigen was discharged within 5 days, together with any infiltrated PMN. Macrophages and NK cells numbered less than PMN. In mice treated with anti-PMN antiserum before HSV infection, PMN infiltration was significantly suppressed 1 day after infection, and these animals developed a severe cutaneous disease even if infected with an attenuated virus. These results indicate the importance of PMN in the control of HSV cutaneous infections, especially in the primary infectious phase.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004030050380
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  • 122
    Digitale Medien
    Digitale Medien
    Cellular localization of cyclo-oxygenase isozymes in Crohn’s disease and colorectal cancer (1999)
    Springer
    International journal of colorectal disease 14 (1999), S. 212-218 
    Details
    ISSN: 1432-1262
    Schlagwort(e): Key words Cyclo-oxygenase ; Colon carcinogenesis ; Crohn’s disease ; Familiar adenomatous polyposis coli ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Deregulation of cyclo-oxygenase isozyme expression has been shown to be a consistent feature of inflammatory bowel diseases and colorectal cancer in humans. This study investigated the cellular localization of aberrant cyclo-oxygenase expression in normal and diseased colon. Biopsies of seven normal colonic tissues, eight tissue samples from patients suffering from Crohn’s disease, five polyps from patients with familiar adenomatous polyposis coli, and ten sporadic adenocarcinomas were analyzed using isozyme-selective immunoprecipitation, western blotting, and immunohistochemistry. Cyclo-oxygenase-1 expression was demonstrated in normal human colon, Crohn’s disease, and colorectal tumors. In normal colon and also in adenomatous polyps, cyclo-oxygenase-1 specific immunosignals were localized to epithelial cells of the upper part of the crypts and endocrine cells of the lower part. In Crohn’s disease cyclo-oxygenase-1 expression was restricted to cells of the inflammatory infiltrate. While barely detectable in normal colon, cyclo-oxygenase-2 protein was strongly increased in epithelial cells located in the uppermost part of the crypts, in surface epithelial cells, and in mononuclear cells of the lamina propria of Crohn’s disease. The constitutive overexpression of cyclo-oxygenase-2 protein observed in the majority of the adenomatous polyps and all adenocarcinomas was attributed to both epithelial and interstitial cells in that the latter predominated in adenomas, and epithelial cells were the prevailing cyclo-oxygenase-2 expressing cell type in adenocarcinomas. In conclusion, both autocrine and paracrine effects of aberrant cyclo-oxygenase-2 expression may contribute to the development of Crohn’s disease and colonic tumor development.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003840050213
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  • 123
    Digitale Medien
    Digitale Medien
    The birthdates of GABA-immunoreactive amacrine cells in the rat retina (1999)
    Springer
    Experimental brain research 128 (1999), S. 309-314 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Key words GABA ; Bromodeoxyuridine ; Proliferation ; Immunohistochemistry ; Retina ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The birthdates of GABAergic amacrine cells in the rat retina were investigated by immunocytochemistry using anti-GABA and anti-bromodeoxyuridine (BrdU) antisera. The ratio of co-localization of GABA to BrdU increased gradually from embryonic-day 13 (E13) and showed a peak value on E18 in the central retina and on E20 in the periphery. After birth, until postnatal-day 3 (P3), a few co-localized cells were observed in the inner nuclear layer (INL). However, in the peripheral retina, co-localized cells were observed in the INL and ganglion cell layer until P5. Our results suggest that the birthdates of GABA-immunoreactive cells vary, depending on cell-type and that there is a temporal lag in the GABA-immunoreactive cell production in the peripheral retina relative to the central retina.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002210050851
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  • 124
    Digitale Medien
    Digitale Medien
    Pathologie der Rhabdo- myosarkome des Kindes- und Adoleszentenalters Ein Bericht des Kindertumorregisters bei der Gesellschaft für Pädiatrische Onkologie und Hämatologie (GPOH) (1999)
    Springer
    Der Pathologe 20 (1999), S. 87-97 
    Details
    ISSN: 1432-1963
    Schlagwort(e): Schlüsselwörter Rhadomyosarkom ; Klassifizierung ; Immunhistochemie ; Genetik ; Prognose ; Key words Rhabdomyosarcoma ; Classification ; Immunohistochemistry ; Genetics ; Prognosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary Rhabdomyosarcoma (RMS) is the most important and a very heterogeneous group of malignant soft tissue tumors of childhood and adolescence.The two major subtypes (embryonal and alveolar) share a common myogenic differentiation, but seem to be histogenetically not related. The so-called ’International Classification of Rhabdomyosarcoma’ includes, besides the two major subtypes, the botryoid and leiomyomatous subtypes of embryonal RMS which are associated with a better prognosis and are treated less aggressively according to current protocols. In addition, the solid variant of alveolar RMS is included in the alveolar group of RMS. The identification of the various subtypes is necessary and important because the treatment with the current protocols is also related to histology. Using conventional stains and immunohistochemistry, these subtypes are distinguishable. Genetic analysis can be helpful in the demonstration of t(2;13) or t(1;13) translocations in alveolar RMS. The identification of alveolar RMS with t(1;13) translocation might become important in the future, because this type of translocation seems to be related to a better prognosis as compared to tumors with a t(2;13) translocation.
    Notizen: Zusammenfassung Rhabdomyosarkome stellen eine heterogene Gruppe von ganz verschiedenartigen, histogenetisch wohl nicht zusammengehörenden Tumoren dar. Nach der heute verwendeten „Internationalen Klassifikation” der Rhabdomyosarkome werden neben der Unterteilung in embryonalen und alveoläre Rhabdomyossarkome auch Subtypen des embryonalen RMS identifiziert (botryoider und leiomyomatöser Subtyp), die durch eine günstigere Prognose und durch die Notwendigkeit einer weniger aggressive Therapie gekennzeichnet sind. Durch Einsatz von verschiedenen histologischen und immunhistochemischen Färbungen ist die Identifizierung der verschiedenen Typen der RMS heute möglich und auch zwingend notwendig, da die einzelnen Entitäten nach ganz unterschiedlichen Therapieprotokollen behandelt werden. Der Nachweis typischer molekulargenetischer Veränderungen kann in der Unterscheidung insbesondere von embryonalen und alveolären RMS hilfreich sein. In der Regel ist die Abgrenzung zwischen diesen beiden Entitäten auch an konventionell gefärbten Schnittpräparaten möglich. Die Identifizierung von alveolären RMS mit einer t(1;13)-Translokation könnte in Zukunft eine große Bedeutung haben, da diese genetische Veränderung möglicherweise mit einer günstigeren Prognose assoziert sein könnte als die t(2;13)-Translokation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002920050326
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  • 125
    Digitale Medien
    Digitale Medien
    Pleomorphes Adenom (Mischtumor) des äußeren Gehörgangs Zur Differentialdiagnose der Tumoren der Zeruminaldrüsen (1999)
    Springer
    Der Pathologe 20 (1999), S. 125-129 
    Details
    ISSN: 1432-1963
    Schlagwort(e): Schlüsselwörter Pleomorphes Adenom ; Äußerer Gehörgang ; Zeruminom ; Differentialdiagnose ; Immunhistochemie ; Key words Pleomorphic adenomas ; Meatus acusticus externus ; Ceruminoma ; Differential diagnosis ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary A tumor was removed from the right external auditory canal of a 69-year old female patient. The histopathological and immunhistochemical evaluation revealed a pleomorphic adenoma (mixed tumor). The differential diagnosis of the tumors derived from the ceruminal glands, their clinical and prognostic implications as well as the histogenesis of pleomorphic adenomas in this localization are discussed.
    Notizen: Zusammenfassung Bei einer 69jährigen Patientin wurde aus dem rechtsseitigen äußeren Gehörgang ein Tumorknoten exstirpiert. Die histopathologische und immunhistochemische Untersuchung ergab ein pleomorphes Adenom (Mischtumor). Die Differentialdiagostik der von den Zeruminaldrüsen abgeleiteten Tumoren, deren klinisch-prognostische Konsequenz sowie die Histogenese der pleomorphen Adenome in dieser besonderen Lokalisation werden erörtert.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002920050331
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  • 126
    Digitale Medien
    Digitale Medien
    Glycine- and GABA-immunoreactive nerve terminals apposed to α-motoneurons during postnatal development in kittens: a quantitative study using the disector (1999)
    Springer
    Experimental brain research 129 (1999), S. 229-240 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Key words Lumbar motoneurons ; Immunohistochemistry ; Light microscopy ; GABA and glycine colocalization ; Stereology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The distribution of γ-aminobutyric acid (GABA) and/or glycine-immunoreactive (IR) terminal-like structures apposed to somatic and dendritic membrane of lumbar α-motoneurons in column 2 was examined in 1- and 3-week-old kittens and in the adult cat. This quantitative study was carried out using a postembedding technique on semithin sections and a stereological method, the disector. Analysis of immunoreactive terminals showed that the percentages of GABA-IR and glycine-IR terminals (these populations include terminals containing both GABA and glycine) apposed to somatic and proximal dendritic compartments of α-motoneurons are almost the same in kittens, while in the adult glycinergic innervation becomes predominant. This change results from: (1) the decrease in numbers of GABA-IR terminals contacting the somatic compartment between 3 weeks and adult stage, while the numbers of glycine-IR terminals show no significant changes after birth and the numbers of terminals containing both neurotransmitters (GABA-IR+glycine-IR) present transient changes and (2) the postnatal increase in the dendritic compartment, in numbers of GABA-IR, glycine-IR and GABA-IR+glycine-IR terminals; the increase being larger for glycine-IR terminals. Furthermore, using a postembedding immunogold technique, observations by electron microscopy showed that GABA-IR P boutons apposed to M boutons can already be identified at 1 week after birth.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002210050893
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  • 127
    Digitale Medien
    Digitale Medien
    Immunolocalisation studies of matrix metalloproteinases-1, -2 and -3 in human melanoma (1999)
    Springer
    Virchows Archiv 435 (1999), S. 574-579 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Key words Melanoma ; Matrix metalloproteinases ; Collagenase ; Gelatinase ; Stromelysin ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The matrix metalloproteinases (MMPs) are considered to have an important role in connective tissue degradation and have been implicated in the mechanisms of tumour invasion and metastatic spread. We have used immunohistochemistry to examine and compare the tissue distributions of collagenase-1 (MMP-1), gelatinase A (MMP-2) and stromelysin-1 (MMP-3) in 18 specimens of malignant melanoma, viz. 10 superficial spreading and 8 nodular melanomas. MMPs-1, -2 and -3 were demonstrated within melanoma and host tissue cells, especially at the periphery of some tumours, but were usually restricted to less than 10% of total melanoma cells. The MMPs were absent from ’normal’ skin tissue distant from the tumour. MMP-2 was localised to discrete groups of cells and was especially evident at the epidermal:tumour interface, whereas MMP-3 was mainly confined to the deeper margins of melanoma. No regular pattern of MMP expression was observed for either the superficial spreading or the nodular melanomas. The variable distributions of the MMPs suggested that enzyme expression was subject to local microenvironmental regulation, possibly in response to matrix components and the cellular heterogeneity observed at the tumour margins. These in situ observations add weight to the concept that specific MMPs contribute to the mechanisms of tumour invasion.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004280050443
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  • 128
    Digitale Medien
    Digitale Medien
    Innervation of human adrenal gland and adrenal cortical lesions (1999)
    Springer
    Virchows Archiv 435 (1999), S. 580-589 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Abstract Adrenal cortex ; Adrenal tumour ; Innervation ; Immunohistochemistry ; Neuronal markers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The innervation of the human adrenal gland and of cortical lesions was studied in sections of cortical tissue (n=10), hyperplastic cortical tissue (n=3), and tissue from cortical adenomas (n=5) and carcinomas (n=6). The presence and distribution of nerve structures containing neuronal markers indicating sympathetic and parasympathetic innervation were studied by immunohistochemistry and the co-existence and co-localization patterns of the different markers by immunofluorescence. The cortex and hyperplastic cortical tissue had a moderate to rich supply of nerve structures containing the typical neuronal markers: protein gene product 9.5 (PGP 9.5), neuron-specific enolase (NSE), small vesicle synaptic protein type 2 (SV2), and nerves showing immunoreactivity to the adrenergic marker tyrosine hydroxylase (TH). All these immunoreactive nerves were located predominantly adjacent to blood vessels, but also among parenchymal cells. The cortex showed numerous nerve structures containing the neuropeptide substance P (SP), neuropeptide Y (NPY) and vasoactive intestinal protein (VIP), but few nerves containing these peptides were seen in hyperplastic cortical tissue. Typical markers were occasionally observed in cortical adenomas but were not found in carcinomas, except in a few cases where PGP 9.5 and NSE were present, but only adjacent to necrotic areas. Nerves containing NPY and VIP occurred in varying numbers in both adenomas and carcinomas. NPY- and VIP-immunoreactive nerve structures were seen mostly alongside blood vessels. There were several types of co-existence. For instance, NSE/VIP-, TH/VIP- and TH/NPY-immunoreactive nerve structures were often seen in the same trunk, but were only partly co-localized.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004280050444
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  • 129
    Digitale Medien
    Digitale Medien
    In situ demonstration of parathyroid hormone-related protein mRNA in sclerosing hepatic carcinoma (1999)
    Springer
    Virchows Archiv 435 (1999), S. 137-142 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Key words Sclerosing hepatic carcinoma ; Hypercalcaemia ; Parathyroid hormone-related protein (PTHrP) ; Immunohistochemistry ; In situ hybridization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  A 69-year-old man had a hepatic tumour occupying the left and half of the right lobe, with portal vein thrombus. There were hypercalcaemia and hypophosphataemia with increased nephrogenous cyclic adenosine monophosphate; bone metastases were excluded. Serum parathyroid hormone-related protein (PTHrP) was elevated, but no increase in intact parathyroid hormone (PTH) or vitamin D3 metabolites was found. At autopsy the histological features were typical of sclerosing hepatic carcinoma. By immunohistochemistry PTHrP was detected in cancer cell nests but not in the fibrous stroma. PTHrP transcripts were demonstrated by in situ hybridization using a polymerase chain reaction (PCR)-derived single-stranded DNA probe. Tumour cells expressed AE1 and CA19-9 (markers for cholangioepithelium) and CEA (for bile canaliculi). Electron microscopy revealed microvilli on the apical surface, and secretory granules 100 nm in diameter were observed. These findings indicate that this case is one of cholangiocellular sclerosing hepatic carcinoma. The interaction between cancer and stromal cells may be the cause of PTHrP overexpression.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004280050411
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  • 130
    Digitale Medien
    Digitale Medien
    Immunohistochemical demonstration of oncocytes in nongonadotrophic pituitary adenomas (1999)
    Springer
    Virchows Archiv 435 (1999), S. 428-433 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Key words Pituitary adenomas ; Growth hormone- producing adenomas ; Immunohistochemistry ; Mitochondria ; Oncocytes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  An immunohistochemical study to demonstrate oncocytes in nongonadotrophic pituitary adenomas was performed. The adenomas were 10 prolactinomas, 2 ACTH-producing adenomas (ACTHomas), and 28 growth hormone-producing adenomas (GHomas); we also studied 5 pituitary oncocytomas. GHomas were divided into two groups: GHomas with (GHomas-1) and without (GHomas-2) fibrous bodies. A small number of solitary large cells showed intense cytoplasmic granular reactivity for mitochondrial protein and cytochrome oxidase, resembling oncocytes in oncocytomas. The proportions of the mitochondrial protein-positive cells ranged from zero to 2.1% (0.3±0.4%). They were more frequent in GHomas, GHomas-1 in particular, than other types of adenomas (P〈0.01), and were mostly negative in prolactinomas and ACTHomas. In multivariate analysis, the proportions showed positive correlation with age (P〈0.01) and the Ki-67 (MIB-1) labeling index (P〈0.01) and tended to increase in number with recurrence (P〈0.05). In GHomas, these cells were more common in cases with low basal GH level (P〈0.01) and large tumor volume (P〈0.01). We consider that these cells represent oncocytes existing in varying numbers in adenomas. We suggest that oncocytic change in nongonadotrophic adenomas indicates poor differentiation and/or some aggressiveness, which lead to a decrease in the endocrine activity of the tumor.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004280050421
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  • 131
    Digitale Medien
    Digitale Medien
    Thermal Decomposition Mechanism and Thermodynamic Properties of [Cd(NTO)4Cd(H2O)6]·4H2O (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 797-806 
    Details
    ISSN: 1572-8943
    Schlagwort(e): cadmium coordination ; crystal structure ; enthalpy of solution ; lattice energy ; lattice enthalpy ; NTO salt ; preparation ; standard enthalpy of dehydration ; standard enthalpy of formation ; thermal decomposition mechanism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract [Cd(NTO)4Cd(H2O)6]·4H2O was prepared by mixing the aqueous solution of 3-nitro-1,2,4-triazol-5-one and cadmium carbonate in excess. The single crystal structure was determined by a four-circle X-ray diffractometer. The crystal is monoclinic, space group C2/c with crystal parameters of a=2.1229(3) nm, b=0.6261(8) nm, c=2.1165(3) nm, β=90.602(7)°, V=2.977(6) nm3, Z=4, Dc=2.055 g·cm−3, μ=15.45 cm−1, F(000)=1824, λ(MoKα)=0.071073 nm. The final R is 0.0282. Based on the results of thermal analysis, the thermal decomposition mechanism of [Cd(NTO)4Cd(H2O)6]·4H2O was derived. From measurements of the enthalpy of solution of [Cd(NTO)4Cd(H2O)6]·4H2O in water at 298.15 K, the standard enthalpy of formation, lattice energy, lattice enthalpy and standard enthalpy of dehydration have been determined as -(1747.8±4.8), -2394, -2414 and 313.6 kJ mol−1 respectively.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010121514909
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  • 132
    Digitale Medien
    Digitale Medien
    Crystal Structures of trans-Tetrahydrotetrols of Benzo[a]pyrene and Chrysene: A Possible Structure-Activity Relationship in Quasi-Planar Bay-Region Polycyclic Aromatic Hydrocarbons (1999)
    Springer
    Structural chemistry 10 (1999), S. 135-148 
    Details
    ISSN: 1572-9001
    Schlagwort(e): Tetrahydrotetrol ; polycyclic aromatic hydrocarbon derivative ; carcinogen ; crystal structure ; structure-activity relationship
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The molecular structures of two racemic trans-tetrahydrotetrols formed by hydrolysis of the (±)anti-7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydro derivatives of the strong carcinogen benzo[a]pyrene and the weak carcinogen chrysene have been determined by X-ray crystallographic methods.3 Focusing on the (+)isomers, the stereochemical features of the two tetrols are discussed in detail to determine structural differences, which can be related to the different biological activity of their parent hydrocarbons, since they provide a model for the hydrocarbon moiety in the major PAH-DNA adduct. As a result of this study, a tentative correlation can be stated between biological activity of quasi-planar bay-region PAHs and the presence of structural features, which can decrease the steric hindrance of the aromatic skeleton and the other hydroxy groups on the pseudo-axial O4, which mimics the position of the covalent bond to DNA. The significant structural features seem to be an out-of-plane distortion with a negative torsion angle at the bay region and a half chair conformation of the saturated ring distorted toward the envelope with C8 at the tip as in BPT, in addition to the axial and pseudo-axial conformations of the hydroxy groups at C9 and C10 due to the near bay region. They may be considered generated by trans-opening of the oxirane ring in an anti-diol epoxide biologically active because it is highly strained. The strains, derived from the activation of bay-region PAHs with a negative torsion angle, seem greater in an anti-diol epoxide relative to the syn-isomer. Thus, when the strains are released, the derived trans-tetrol occurs with structural features, which seem to better fit the target. As a consequence, the presence of a methyl group at a bay region should increase the biological activity of a PAH, imposing greater strains to the structure of the anti-diol epoxide.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1022037431181
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  • 133
    Digitale Medien
    Digitale Medien
    Survey of Chalcogenide Superconductors (1999)
    Springer
    Journal of thermal analysis and calorimetry 57 (1999), S. 807-821 
    Details
    ISSN: 1572-8943
    Schlagwort(e): bibliography ; critical temperature ; crystal structure ; CuRh2S4 ; CuRh2Se4 ; survey of chalcogenide superconductors
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The thread that runs through all research in the field of superconductivity is new physics through discovery of new materials. The knowledge of superconducting materials has become voluminous and complex. The comprehensive review of the superconducting materials is of particular importance. The main purpose of this report is to present the results of classification for chalcogenide superconductors. Superconducting critical temperature Tc, crystal-structure type and the references proper to these compounds are summarized. Brief survey of the superconductivity in chalcogen elements is also given. Furthermore, as representative sulfide and selenide, superconducting characteristics of CuRh2S4 and CuRh2Se4 will be shown.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010142225299
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  • 134
    Digitale Medien
    Digitale Medien
    Thermal Decomposition Mechanism, Thermodynamical and Quantum Chemical of Properties [Pb(NTO)2⋅(H2O)] (1999)
    Springer
    Journal of thermal analysis and calorimetry 58 (1999), S. 257-267 
    Details
    ISSN: 1572-8943
    Schlagwort(e): crystal structure ; lattice energy ; lattice enthalpy ; lead salt of NTO ; preparation ; quantum chemical calculation ; thermal decomposition mechanism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The single crystal of lead salt of 3-nitro-1,2,4-triazol-5-one (NTO), [Pb(NTO)2(H2O)] was prepared and its structure was determined by a four-circle X-ray diffractometer. The crystal is monoclinic, its space group is P21/n with crystal parameters of a=0.7262(1) nm, b=1.2129(2) nm, c=1.2268(3) nm, β=90.38(2)°, V=1.0806(2) nm3, Z=4, Dc=2.97 g cm−3, µ=157.83cm−1, F(000)=888. The final R is 0.027. By using SCF-PM3-MO method we obtained optimized geometry for [Pb(NTO)2⋅H2O] and particularly positions for hydrogen atoms. Through the analyses of MO levels and bond orders it is found that Pb atom bond to ligands mainly with its 6pz and 6py AOs. The thermal decomposition experiments are elucidated when [Pb(NTO)2⋅H2O] is heated, ligand water is dissociated first and NO2 group has priority of leaving. Based on the thermal analysis, the thermal decomposition mechanism of [Pb(NTO)2⋅H2O] has been derived. The lattice enthalpy and its lattice energy were also estimated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1010190811770
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  • 135
    Digitale Medien
    Digitale Medien
    Synthesis of a Novel Nickel(II) Complex with Dithiocarbimate from Sulfonamide (1999)
    Springer
    Structural chemistry 10 (1999), S. 41-45 
    Details
    ISSN: 1572-9001
    Schlagwort(e): Nickel complex ; dithiocarbimate ; sulfonamide ; crystal structure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Potassium N-4-methylphenylsulfonyldithiocarbimate, K2(4-CH3C6H4SO2N=CS2), reacted with nickel(II) chloride hexahydrate and tetrabutylammonium bromide to form the bis(N-4-methylphenylsulfonyldithiocarbimate)nickelate(II) tetrabutylammonium salt (Bu4N)2[Ni(4-CH3C6H4S2C=NSO2)2]. The elemental analyses, IR and UV-Vis data obtained were consistent with the formation of a $${\text{nickel}}{\kern 1pt} - {\kern 1pt} {\text{sulfur}}$$ diamagnetic planar complex. The 1H NMR and the 13C NMR spectra showed the expected signals for the dithiocarbimate moiety and the tetrabutylammonium cation. The single-crystal structure analysis showed that this substance crystallizes in the triclinic $${P\bar 1}$$ space group with a = 10.474(3) Å, b = 10.767(3) Å, c = 13.657(3) Å and α = 81.54(2)°, β = 80.44(2)°, γ = 67.63(2)°, V = 1398.5(8) Å3, and Z = 2. The nickel atom is coordinated to four sulfur atoms.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1022018028224
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  • 136
    Digitale Medien
    Digitale Medien
    4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone, a Nicotine-derived Carcinogenic Nitrosaminoketone (NNK): Three-dimensional Structure (1999)
    Springer
    Structural chemistry 10 (1999), S. 439-443 
    Details
    ISSN: 1572-9001
    Schlagwort(e): Nicotine-derived nitrosaminoketone ; nitrosamine ; crystal structure ; molecular dimensions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The three-dimensional structure of the carcinogenic nicotine-derived nitrosaminoketone, 4-(methyl-nitrosamino)-l-(3-pyridyl)-l-butanone, has been determined by X-ray crystallographic techniques. The molecule is essentially planar except for the methylnitrosamine group which is oriented at a dihedral angle of 68.7° to the pyridine ring. Molecules pack by way of —H⋯O interactions that involve the —NNO group.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1022431223064
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  • 137
    Digitale Medien
    Digitale Medien
    The interaction of Bcl-2 and Bax regulates apoptosis in biliary epithelial cells of rats with obstructive jaundice (1999)
    Springer
    Virchows Archiv 434 (1999), S. 333-339 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Key words Apoptosis ; Programmed cell death ; Ductular proliferation ; Biliary decompression ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  A complex molecular network controls cell homeostasis by inducing apoptosis or proliferation. The balance of Bcl-2 and Bax, members of a protein family, determines whether a cell will become immortal (Bcl-2) or will undergo apoptosis (Bax). To determine the role of Bcl-2 and Bax during proliferation of biliary epithelial cells (BEC) after bile duct ligation (BDL) and their regression after biliary decompression we induced hyperplasia of BEC by BDL in male rats. Regression of hyperplastic BEC by way of apoptosis was induced by biliary decompression through a Roux-en-Y biliodigestive anastomosis. To quantify apoptosis a modified TUNEL assay was used. Expression of Bcl-2 and Bax was visualized by immunohistochemistry and quantified stereologically. BEC increased from 〈1% to 〉20% after BDL; this increase was associated with overexpression of Bcl-2 in up to 30% of hyperplastic BEC. After biliodigestive anastomosis, apoptotic BEC increased from 〈0.1% to a peak of 5.4% after 1 day to reach baseline again 1 week after decompression. This was associated with de novo appearance of Bax. The interaction between Bcl-2 and Bax triggers apoptosis in BEC and acts as a cell rheostat in BEC hyperplasia and its involution after biliary decompression.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004280050349
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  • 138
    Digitale Medien
    Digitale Medien
    Intimal-type primary sarcoma of the aorta (1999)
    Springer
    Virchows Archiv 435 (1999), S. 62-66 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Key words Rhabdomyosarcoma ; Aorta ; Immunohistochemistry ; Electron microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  We report an intimal sarcoma presenting as an aortic aneurysm. A 68-year-old man suffered from chest pain and speech disturbance. Computed tomography showed a sacciform aneurysm of the aorta, which was resected, revealing a polypoid tumour measuring 1.5×2×2.5 cm projecting into the lumen. This proved to be a poorly differentiated high-grade sarcoma having morphological, immunophenotypic and ultrastructural features consistent with rhabdomyosarcomatous differentiation. Primary sarcomas of the aorta are extremely rare. Many cases have been diagnosed as ”intimal” on the basis of their site of origin, and they are not easy to classify from their histological pattern. Electron microscopy and the use of a more comprehensive panel of immunohistochemical markers should be applied in the histological classification of ”intimal” sarcoma.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004280050396
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  • 139
    Digitale Medien
    Digitale Medien
    Immunohistochemical study of cytochrome P450 2C and 3A in human non-neoplastic and neoplastic tissues (1999)
    Springer
    Virchows Archiv 434 (1999), S. 401-411 
    Details
    ISSN: 1432-2307
    Schlagwort(e): Key words Human ; Cytochrome P450 2C ; Cytochrome P450 3A ; Immunohistochemistry ; Neoplasms
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Organ and cellular distribution and expression constancy of microsomal cytochrome P450 (CYP) 2C and 3A in humans were studied with new polyclonal antibodies to CYP2C (MP-1) and 3A (NF-2) active in formalin-fixed, paraffin-embedded tissues. Antibodies were raised against purified human CYP2C9 and CYP3A4. On western blotting, MP-1 reacted with 2C8, 2C9, 2C18 and 2C19, and NF-2 with 3A4. In both frozen and paraffin sections, hepatocytes showed diffuse immunoreactivity with MP-1 and centrilobular staining with NF-2. Inparaffin sections of 40 kinds of nonneoplastic tissues, epithelium of the small and large intestine, bile duct, nasal mucosa, kidney and adrenal cortex stained positively with both MP-1 and NF-2 antibodies. Epithelium of gastric fundic glands, salivary glands, tracheobronchial glands, Brunner’s glands, the prostate, uterine cervix and nasopharynx showed definite reactivity with MP-1. Epithelium of the gastric mucosa with intestinal metaplasia, duodenum, gallbladder and intercalated ducts of the pancreas and chief cells of the parathyroid and the corpus luteum of the ovary reacted with NF-2. Among the neoplastic tissues, MP-1 reacted with pleomorphic adenoma of the salivary gland and carcinomas of six different organs, and NF-2 with those of 7 different organs. These results indicate that CYP2C and CYP3A are distributed widely and organ specifically, as well as being variably expressed in neoplastic and normal states.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004280050359
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  • 140
    Digitale Medien
    Digitale Medien
    Nitric oxide synthase in the gastrointestinal tract of the estuarine crocodile, Crocodylus porosus (1999)
    Springer
    Cell & tissue research 296 (1999), S. 433-437 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words Nitric oxide ; Vasoactive intestinal polypeptide (VIP) ; Immunohistochemistry ; Enteric nervous system ; Crocodylus porosus (Crocodilia)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  The aim of this study was to investigate the distribution of nitric oxide synthase (NOS)-containing nerve cells in the gastrointestinal tract of a reptile and to compare it with the pattern in other vertebrate classes. In the estuarine crocodile, Crocodylus porosus, NOS-positive nerve cell bodies and fibres were found in all regions of the gut examined. Most myenteric microganglia contained one or several NOS-immunoreactive neurons together with unlabelled neurons. The majority of the neurons were multipolar, ranging from 10 to 25 µm in diameter. Both the circular and the longitudinal muscle layers were innervated by NOS-immunoreactive nerve fibres, which mostly ran parallel to the muscle fibres. In addition, small blood vessels in the submucosa and on the serosal surface of the gut were innervated by NOS-immunoreactive fibres. Double labelling with antisera to NOS and vasoactive intestinal peptide (VIP) revealed three neuronal subpopulations. A small proportion of the NOS-immunoreactive cells also contained immunoreactivity to VIP while a majority of the VIP-immunoreactive cells were NOS immunoreactive. There were more nerve fibres showing VIP immunoreactivity than fibres with NOS immunoreactivity, although most of the latter also contained immunoreactivity to VIP. VIP-immunoreactive fibres often surrounded the NOS-immunoreactive nerve cells. These results suggest that neuronally released nitric oxide is likely to be involved in the control of gastrointestinal motility in the crocodile as in most other vertebrate species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410051303
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  • 141
    Digitale Medien
    Digitale Medien
    Immunolocalization of hyaluronic acid and inter-alpha-trypsin inhibitor in mice (1999)
    Springer
    Cell & tissue research 296 (1999), S. 587-597 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words Hyaluronic acid ; Immunohistochemistry ; Inter-alpha-trypsin inhibitor ; Localization ; Mouse (CD-1)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  The direct interaction of hyaluronic acid (HA) and heavy chain (HC) of the inter-alpha-trypsin inhibitor (IαI) family plays a critical role in the organization and stabilization of the extracellular matrix. The aim of the present investigation was to elucidate the distribution of the IαI HC and HA in adult mouse tissues. An immunohistochemical method using a rabbit polyclonal antibody raised against mouse IαI heavy-chain peptide and a specific probe for HA (biotinylated HA-binding protein) was used to demonstrate an immunolocalization of IαI HC and HA. Distribution and localization of HA was of three types, namely, colocalization with IαI HC itself (cartilaginous tissue and ovary), localization around IαI HC immunostaining (lung, intestine and skeletal muscle), and localization at a small distance from IαI HC or a different distribution pattern (brain, liver, skin and kidney). These results indicate that IαI HC could function as an HA-rich matrix stabilizer on the cells of cartilage and maturing ovary, in which IαI HC shows colocalization with its predominant ligand, HA.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410051320
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  • 142
    Digitale Medien
    Digitale Medien
    Differentiation of pinopsin-immunoreactive cells in the developing quail pineal organ: an in-vivo and in-vitro immunohistochemical study (1999)
    Springer
    Cell & tissue research 296 (1999), S. 667-671 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words Avian pineal organ ; Pinopsin ; Cell differentiation ; Tissue culture ; Immunohistochemistry ; Quail embryo
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  The avian pineal organ contains several types of photoreceptors with different photopigments: rhodopsin, iodopsin, and pinopsin. We have previously examined the differentiation of both rhodopsin-like and iodopsin-like immunoreactive cells during pineal development in quail embryos to determine the onset of synthesis of specific proteins and their cellular localization. In the present study, we have performed pinopsin immunohistochemistry on in-vivo developing and in-vitro cultured pineal organs of quail embryos. The results were compared with those obtained with rhodopsin and iodopsin immunohistochemistry. In the developing pineal organs, pinopsin immunoreactivity was detected at embryonic day 8, i.e. five days earlier than rhodopsin-like and iodopsin-like immunoreactivities. It was localized exclusively in the protrusions extending into the lumen throughout development, whereas rhodopsin-like and iodopsin-like immunoreactivities were usually found both in cell bodies and processes. These differences were also observed under two different types of culture conditions (dissociated cell culture and organ culture) indicating that, in the avian pineal organ, the expression pattern of the pinopsin gene is basically different from those of the other two pineal photopigments. The present study suggests that pineal cells have a mechanism for the polarized transport of pinopsin molecules.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410051326
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  • 143
    Digitale Medien
    Digitale Medien
    The antisecretory factor: synthesis and intracellular localisation in porcine tissues (1999)
    Springer
    Cell & tissue research 296 (1999), S. 607-617 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words Gastrointestinal tract ; Respiratory tract ; Urogenital tract ; Immunohistochemistry ; In situ hybridization ; mRNA ; Pig (Swedish Landrace × Yorkshire)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  The antisecretory factor, AF, is a 41-kDa protein, cloned and sequenced from a human pituitary library. AF is a potent inhibitor of experimental intestinal hypersecretion in rats and pigs. An antiserum against the C-terminal of the truncated, recombinantly produced AF protein was raised in rabbits. The affinity-purified antiserum was used to study the expression of AF in mucosal membranes and in the pituitary gland of the pig; distinctly stained cells were found in lymphoid cells in the connective tissue of all parts of the gastrointestinal, respiratory and urinary tracts. Cytoplasmic AF was demonstrated in endocrine and epithelial cells in the pituitary gland. In situ hybridisation with a digoxigenin-labelled mRNA probe also demonstrated specific cytoplasmic staining in epithelial and lymphoid cells in all of these tissues. The cells stained by either method were similarly distributed topographically within the tissues. The results suggest that a specific defined cell population in these various tissues possesses the capability of both synthesising and storing the AF protein within the cellular cytoplasmic compartment.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410051322
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  • 144
    Digitale Medien
    Digitale Medien
    Expression of vascular endothelial growth factor (VEGF) and its receptors during embryonic implantation in the golden hamster (Mesocricetus auratus) (1999)
    Springer
    Cell & tissue research 296 (1999), S. 339-349 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words Vascular endothelial growth factor ; flt-1 ; flk-1 ; Embryonic implantation ; Immunohistochemistry ; In situ hybridization ; Reverse transcription/polymerase chain reaction ; Golden hamster (Mesocricetus auratus)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  Expression of vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) and its receptors (flt-1 and flk-1) during the peri-implantation period (days 3, 4, 5, 6 and 7 post coitus) in the golden hamster was investigated by in situ hybridization, immunohistochemistry and the reverse transcription/polymerase chain reaction (RT-PCR). Three days after mating, in situ hybridization and immunohistochemical staining revealed weak VEGF expression only in the uterine epithelium; this expression was similar to that seen at oestrus. Flt-1 but no flk-1 immunoreactivity was observed. At day 4, the subepithelial stroma and embryo displayed immunoreactivity for VEGF and flt-1, whereas endothelial cells expressed both flt-1 and flk-1. At day 5, immunoreactivity for both VEGF and its receptors was detected in decidual cells and vascular endothelial cells. Only a few embryonic cells expressed VEGF mRNA but strong signals were noted in decidual cells. The patterns of VEGF and VEGF receptor expression were the same in the day-6 and day-7 embryos and decidua, except for an increase in intensity as development progressed. Based on these findings, we conclude that, in addition to its known actions on endometrial angiogenesis and tissue swelling, VEGF may also facilitate the proliferation and differentiation of the endometrium and help to sustain the avascular embryo during this early stage of development.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410051294
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  • 145
    Digitale Medien
    Digitale Medien
    Elongated pericyte-like cells connect discrete capillaries in the cochlear stria vascularis of gerbils and rats (1999)
    Springer
    Cell & tissue research 296 (1999), S. 673-676 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words Basal lamina ; Immunohistochemistry ; Confocal laser microscopy ; Cochlea ; Mongolian gerbil ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  Bridging structures between discrete capillaries in the stria vascularis of the cochlea were studied morphologically in gerbils and rats. Serial thin sections for transmission electron microscopy revealed (1) that elongated cells surrounded by the basal lamina provided the structural basis for the bridging structure, (2) that the basal lamina surrounding the elongated cell extended to the basal lamina around the capillary endothelial cell, (3) that the electron density of the cytoplasm was similar to that of the pericytes around the capillaries, and (4) that the cell was attached to the capillaries at both ends only. Visualization of the basal lamina by immunofluorescent methods revealed (1) that capillaries were often bent at the site of attachment of the bridging cell, (2) that the bridging cell bifurcated occasionally, and (3) that the density of the bridging cell was much higher in the stria vascularis than in the underlying spiral ligament. Filamentous actin visualized by fluorescent phalloidin was not apparent in the bridging cell. We propose that the bridging cell provides mechanical strength to the tortuous capillary network in the stria vascularis and participates in the specific function of the stria vascularis in cooperation with other types of cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410051327
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  • 146
    Digitale Medien
    Digitale Medien
    Immunohistochemical evidence for the presence of tryptophan hydroxylase and serotonin in the rodent Harderian gland (1999)
    Springer
    Cell & tissue research 296 (1999), S. 517-523 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words Harderian gland ; Tryptophan hydroxylase ; Serotonin ; Immunohistochemistry ; Rat (Wistar) ; Syrian hamster ; Mesocricetus auratus ; Djungarian hamster ; Phodopus sungorus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  The Harderian gland is considered as being an extrapineal source of melatonin. In most rodents, the Harderian gland contains two epithelial cell types (I and II). The aim of this study has been to define which cell type is involved in indoleamine synthesis. The presence and localization of serotonin (melatonin precursor) and tryptophan hydroxylase (the rate-limiting enzyme for serotonin synthesis) have been investigated by immunohistochemistry in male Wistar rats, Syrian hamsters and Djungarian hamsters. The results of the present study show that immunoreactivity for tryptophan hydroxylase and serotonin is confined to the type I cell, suggesting that this cell type is involved in indoleamine synthesis in the rodent Harderian gland.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410051312
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  • 147
    Digitale Medien
    Digitale Medien
    Differential expression of nitric oxide synthases in EGF-responsive mouse neural precursor cells (1999)
    Springer
    Cell & tissue research 296 (1999), S. 489-497 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words Nitric oxide synthase isoforms I ; III ; Neurosphere ; Immunohistochemistry ; Nestin ; Embryonic brain striatum ; Mouse (Balb/c)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  Nitric oxide (NO) is a gaseous, radical molecule that plays a role in various physiological processes in the nervous system such as learning and hippocampal plasticity. It is generated from l-arginine by nitric oxide synthases (NOS), which come in three isoforms depending on the tissue of origin, namely inducible-NOS (iNOS in macrophages), endothelial-NOS (eNOS in endothelial cells) and neural-NOS (nNOS in neural cells). We used epidermal growth factor (EGF)-responsive nestin-positive neural precursor cells originating from the mouse E16 embryonic striatum, and studied the relative expression of NOS isoforms probed with isoform-specific antibody using the avidin-biotin immunohistochemical method. Our data revealed both nNOS and eNOS to be expressed in both neurospheres and desegregated neural precursor cells. However, iNOS signals were virtually undetectable in both cell categories. When the neural precursor cells were carried in the presence of poly-l-ornithine (PLO), there was a strong induction of the expression of iNOS proteins, indicating the possibility that this isoform is amenable to modulation by extracellular cues. These preliminary results suggest both nNOS and eNOS to be important in the physiology of neural precursor cells, and that iNOS might also play a role at certain stages in the life of these cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410051309
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  • 148
    Digitale Medien
    Digitale Medien
    P2X receptors in the rat duodenal villus (1999)
    Springer
    Cell & tissue research 297 (1999), S. 111-117 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words P2X receptor ; Immunohistochemistry ; Duodenum ; Rat (Sprague Dawley)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  Immunohistochemical techniques were performed on freshly frozen sections of the duodenum of the rat using specific polyclonal antibodies to unique peptide sequences of P2X1–7 receptors. Of the antibodies to the seven known P2X receptor subtypes that mediate extracellular signalling by nucleotides, three reacted with discrete structures in the duodenal villus of the rat. Anti-P2X1 reacted with the capillary plexus in the intestinal villus, which did not extend to the crypt region, suggesting that nucleotides may be involved in the uptake and transport of metabolites. Anti-P2X5 immunostained the membranes of the narrow ”stem” of villus goblet cells, where the nucleus and cell organelles reside, possibly influencing synthesis and release of mucins. P2X7 receptor immunoreactivity was only seen in the membranes of enterocytes and goblet cells at the tip of the villus, where cells are exfoliated into the lumen, consistent with earlier findings that P2X7 is involved in apoptotic events. Thus, in complex structures such as the intestinal villus, purinoceptors appear to participate in several and diverse signalling functions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410051338
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  • 149
    Digitale Medien
    Digitale Medien
    Ultrastructure and distribution dynamics of chloride cells in tilapia larvae in fresh water and sea water (1999)
    Springer
    Cell & tissue research 297 (1999), S. 119-130 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words Chloride cells (mitochondria-rich cells) ; Teleost larvae ; Osmoregulation ; Immunohistochemistry ; Quantification ; Ultrastructure ; Oreochromis mossambicus (Teleostei)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  Integumental and branchial chloride cells of tilapia larvae (Oreochromis mossambicus) were studied at the light-microscopical and ultrastructural level. Total numbers and distribution of chloride cells were quantified after immunostaining of cross sections of the entire larvae with an antibody against the α-subunit of Na+/K+-ATPase. The majority (66%) of Na+/K+-ATPase-immunoreactive (ir) cells, i.e. chloride cells, of freshwater tilapia larvae were located extrabranchially up to 48 h after hatching. Five days after hatching, the majority (80%) of chloride cells were found in the buccal cavity. Transfer of 24-h-old larvae to 20% sea water speeded up this process; 24 h after transfer (i.e. 48 h after hatching), the majority (59%) of chloride cells were located in the buccal cavity. The branchial chloride cell population of 24-h- and 120-h-old larvae consisted of immature, mature, apoptotic and necrotic chloride cells. However, relatively more immature chloride cells were observed in freshwater larvae (42–63%) than in (previously studied) freshwater adults (21%), illustrating the developmental state of the gills. After transfer to sea water, the incidence of degenerative chloride cells did not change. Furthermore, the incidence of immature cells had decreased and a new subtype of chloride cells, the ”mitochondria-poor” cells, appeared more frequently. These mitochondria-poor chloride cells were characterised by an abundant tubular system and relatively few mitochondria, which were aligned at the border or concentrated in one part of the cytoplasm. Most of these cells did not contact the water. The function of their enhanced appearance after seawater transfer is unknown.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410051339
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  • 150
    Digitale Medien
    Digitale Medien
    Differential distribution of somatostatin sst2 receptor splice variants in rat gastric mucosa (1999)
    Springer
    Cell & tissue research 297 (1999), S. 163-168 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words Acid release ; Stomach ; Antibody ; Immunohistochemistry ; Rat (Sprague Dawley)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  The tetradecapeptide somatostatin (SRIF) has an inhibitory action on acid secretion in the stomach. It has been suggested that somatostatin may act directly on parietal cells as well as indirectly via histamine-producing cells. A family of high affinity membrane-bound receptors, which are termed sst1–sst5 receptors, mediates the physiological effects of somatostatin. On the basis of functional studies it has been suggested that somatostatin may mediate its actions in the stomach by activation of a somatostatin sst2 receptor type. Two splice variants of the rat sst2 receptor exist, sst2(a) and sst2(b), which differ in length and composition of their intracellular carboxy termini. To date, little information is available on the distribution of the somatostatin sst2(b) receptor in any peripheral tissue. Here we show for the first time the localisation of this receptor isoform in the rat oxyntic mucosa, where the receptor protein was found to be present in parietal cells. This is in contrast to sst2(a) receptor, which was localised to enterochromaffin-like cells and nerve fibres. The differential localisation of the receptor isoforms to two key cell types, parietal cells and enterochromaffin-like cells, may explain how somatostatin inhibits acid secretion by more than one mechanism.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410051344
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  • 151
    Digitale Medien
    Digitale Medien
    Immunohistochemical localization of calbindin D28k during root formation of rat molar teeth (1999)
    Springer
    Cell & tissue research 297 (1999), S. 503-512 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words Calbindin ; Hertwig’s epithelial root sheath ; Epithelial rest of Malassez ; Preodontoblast ; Periodontal fibroblast ; Immunohistochemistry ; Rat (Sprague Dawley)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  The present study was undertaken to examine the localization of calbindin D28k (CB)-like immunoreactivity (-LI) during the root formation of the rat molar. In the adult rat, CB-LI was detected in some of the cells of the epithelial rest of Malassez at the bifurcational region and in certain cells between the root dentin and cementum at the apical region. These cells had indented nuclei and many tonofilaments, and cementocytes lacked CB-LI. Moreover, CB-LI was observed in the periodontal fibroblasts in the alveolar half of the apical region. During root formation, the cells in the Hertwig’s epithelial root sheath (HERS) lacked CB-LI, but most fragmented cells along the root surface began to express CB-LI when HERS was disrupted. Preodontoblasts and odontoblasts at the apical portion of the root also showed CB-LI. After the formation of cellular cementum, the CB-immunoreactive (-IR) cells were entrapped between the root dentin and cementum in the apical portion of the root. The number of CB-IR cells at the root surface decreased gradually, while that between the root dentin and cementum increased. The fibroblasts in the periodontal ligament began to express CB-LI after commencement of the occlusion, and the number and the staining intensity of CB-IR fibroblasts increased gradually with the passage of time. The present results suggest that CB may play an important role in the survival of the epithelial cells, in the cellular responses of periodontal fibroblasts against mechanical forces caused by the occlusion, and in the initial mineralization by the odontoblasts through the regulation of intracellular Ca2+ concentration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410051377
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  • 152
    Digitale Medien
    Digitale Medien
    Motor innervation by enteric nerve fibers containing both nitric oxide synthase and galanin immunoreactivities in the striated muscle of the rat esophagus (1999)
    Springer
    Cell & tissue research 295 (1999), S. 241-245 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words Enteric innervation ; Immunohistochemistry ; Nitric oxide synthase ; Galanin ; Striated muscle ; Esophagus ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The relationship between nitric oxide synthase (NOS)- and galanin-immunoreactive nerve terminals and the origin of NOS-immunoreactive nerve terminals on the motor endplates in the striated muscles of the rat esophagus was investigated. Double immunohistochemical staining revealed a dual innervation of motor endplates by calcitonin gene-related peptide (CGRP)-immunoreactive axons and by axons that were immunoreactive for both NOS and galanin. On average, 91% of NOS terminals were galanin immunoreactive. NOS-immunoreactive fibers were revealed at 67% of endplates, identified by the presence of CGRP terminals. The left vagus and superior laryngeal nerve were cut and 15 days allowed for terminals to degenerate. This caused a significant loss of CGRP fibers, but did not affect the density of innervation of the striated muscle by NOS-immunoreactive fibers. Thus the NOS/galanin fibers are deduced to originate from ganglia in the esophageal wall. This is supported by our observation of numerous NOS-immunoreactive nerve cell bodies in the myenteric ganglia of the esophagus, 74% of which were galanin immunoreactive. There were no CGRP-immunoreactive nerve cell bodies in the wall of the esophagus.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410051230
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  • 153
    Digitale Medien
    Digitale Medien
    Serotonin-like immunoreactivity in the stomatogastric nervous systems of crayfishes from four genera (1999)
    Springer
    Cell & tissue research 295 (1999), S. 537-551 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words Decapod ; Invertebrate ; Monoamine ; Immunohistochemistry ; Procambarus clarkii ; Pacifastacusleniusculus (Crustacea)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract We used whole-mount immunocytochemistry to characterize the distribution of serotonin in the stomatogastric nervous systems of seven species of crayfish representing three genera from the family Cambaridae (Orconectes, Cambarus, and Procambarus) and one from the family Astacidae (Pacifastacus). In all species, we observed serotonin-like immunoreactivity in four gastropyloric receptor (GPR) neurons located in the lateral ventricular nerves, with one pair of neurons in each nerve. As in other crustaceans, the GPR axons project to the stomatogastric ganglion and to the bilateral commissural ganglia. In three crayfishes, we observed the GPR axons crossing the commissural ganglia, and extending toward the thoracic nervous system. This feature was most clearly and consistently seen in Pacifastacus leniusculus. The number of stained somata in the commissural ganglia varied among crayfish species from two (in Procambarus clarkii) to five (in Pacifastacus leniusculus). The largest soma (the L cell) displayed both serotonin- and tyrosine hydroxylase-like immunoreactivity in all species, suggesting that serotonin and dopamine are cotransmitters in this cell. The inferior esophageal nerve and a branch of this nerve (the inner labral nerve) contained several axons with serotonin-like immunoreactivity. These axons were clearly present in only one species (Procambarus clarkii). Serotonin acts as a neuromodulator of rhythms produced by circuits in the crab and lobster stomatogastric ganglion, and is likely to play a similar role in crayfish. Differences are apparent in the distribution of serotonin among crayfish species and between crayfish and other crustaceans, and could result in differences in the physiological action of this modulator.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410051259
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  • 154
    Digitale Medien
    Digitale Medien
    Immunohistochemical localization and biochemical characterization of two novel decapeptides derived from POMC-A in the trout hypothalamus (1999)
    Springer
    Cell & tissue research 295 (1999), S. 409-417 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words Proopiomelanocortin ; Post-translational processing ; Novel neuropeptides ; Immunohistochemistry ; HPLC analysis ; Oncorhynchus mykiss (Teleostei)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Several vertebrate species which underwent duplication of their genome, such as trout, salmon and Xenopus, possess two proopiomelanocortin (POMC) genes. In the trout, one of the POMC molecules, called POMC-A, exhibits a unique C-terminal extension of 25 amino acids which has no equivalent in other POMCs characterized so far. This C-terminal peptide contains three pairs of basic residues, suggesting that it may be the source of novel regulatory peptides. The aim of the present study was to investigate the occurrence of these peptides in the brain of the trout Oncorhynchus mykiss by using specific antibodies raised against two epitopes derived from the C-terminal extension of POMC-A, i.e., EQWGREEGEE and YHFQ-NH2. Immunohistochemical labeling of brain sections revealed the presence of EQWGREEGEE- and YHFQ-NH2-immunoreactive cell bodies in the anterior part of the nucleus lateralis tuberis of the hypothalamus. Immunoreactive fibers were observed in the dorsal hypothalamus, the thalamus, the telencephalon, the optic tectum and the medulla oblongata. In contrast, no labeling was detected using antibodies against the non-amidated peptide YHFQG. Biochemical characterization was performed by combining high-performance liquid chromatography (HPLC) analysis with radioimmunoassay (RIA) quantification. Two peptides exhibiting the same retention time as synthetic EQWGREEGEE and ALGERKYHFQ-NH2 were resolved. However, no peptide co-eluting with YHFQ-NH2 or YHFQG could be detected. These results demonstrate that, in the trout brain, post-translational processing of POMC-A generates the two decapeptides EQWGREEGEE and ALGERKYHFQ-NH2. The wide distribution of immunoreactive fibers in the diencephalon, telencephalon, optic tectum and medulla oblongata suggests that these peptides may exert neurotransmitter and/or neuromodulator activities.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410051247
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  • 155
    Digitale Medien
    Digitale Medien
    Localization of leech excitatory peptide, a member of the GGNG peptides, in the central nervous system of a leech (Whitmania pigra) by immunohistochemistry and in situ hybridization (1999)
    Springer
    Cell & tissue research 297 (1999), S. 155-162 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words Central nervous system ; Immunohistochemistry ; In situ hybridization ; Leech excitatory peptide ; Neuropeptide ; Whitmania pigra (Annelida)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  We have recently isolated a myoactive peptide, called leech excitatory peptide, belonging to the GGNG peptide family from two species of leeches, Hirudo nipponia and Whitmania pigra. Immunohistochemistry and in situ hybridization were employed to localize leech excitatory peptide-like peptide(s) and its gene expression in the central nervous system of W. pigra. A pair of neuronal somata were stained by both immunohistochemistry and in situ hybridization in the supraesophageal, subesophageal, and segmental ganglia. In addition, several other neurons showed positive signals by either immunohistochemistry or in situ hybridization in these ganglia. An immunoreactive fiber was observed to run in the anterior root of segmental ganglion 6, which is known to send axons to the sexual organs, though we failed to detect immunoreactivity in possible target tissues. Antiserum specificity was established by enzyme-linked immunosorbent assay using different leech excitatory peptide-related peptides. Leech excitatory peptide elicited muscular contraction of isolated preparations of penis and intestine at concentrations of 10–8 M. These results suggest that leech excitatory peptide is a neuropeptide modulating neuromuscular transmission in multiple systems, including regulation of reproductive behavior.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410051343
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  • 156
    Digitale Medien
    Digitale Medien
    Cellular localization and distribution of glucocorticoid receptor immunoreactivity and the expression of glucocorticoid receptor messenger RNA in rat pituitary gland (1999)
    Springer
    Cell & tissue research 295 (1999), S. 207-214 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Key words Glucocorticoid receptor (GR) ; Immunohistochemistry ; In situ hybridization ; Pituitary ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract By means of double immunohistochemical techniques and a nonradioisotopic in situ hybridization method, we determined the colocalization pattern of glucocorticoid receptor (GR) and pituitary hormones and the GR messenger RNA (mRNA) expression in the pituitaries of Wistar adult male rats. Immunoreactivity for GR was detected in the nuclei of cells in the anterior and posterior pituitary. Double immunohistochemistry revealed that the colocaliza- tion of GR and anterior pituitary hormones occurred in almost 99% of the growth hormone (GH)-producing cells and adrenocorticotropic hormone (ACTH)-producing cells, and in 67% of the thyroid stimulating hormone (TSH)-producing cells. Almost all of the folliculostellate cells (93%), marginal layer cells (94%) in the anterior pituitary, and pituicytes (96%) in the posterior pituitary immunostained for S100 protein antibody were also immunostained with GR. GR mRNA was abundant in the cytoplasm of anterior and intermediate pituitary cells but scattered sparsely in that of the posterior pituitary. These results suggest that glucocorticoids directly influence certain pituitary cells in order to regulate cell function, including the synthesis and/or secretion of hormones.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004410051226
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  • 157
    Digitale Medien
    Digitale Medien
    Vessel size-dependent expression of intermediate-sized filaments, calponin, and h-caldesmon in smooth muscle cells of human coronary arteries (1999)
    Springer
    Heart and vessels 14 (1999), S. 253-261 
    Details
    ISSN: 1615-2573
    Schlagwort(e): Smooth muscle cell ; Heterogeneity ; Coronary artery ; Human ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The arterial media is composed of a heterogeneous population of smooth muscle cells (SMCs). Recently, the properties of SMCs were observed to be heterogeneous not only among individual cells but also among arteries of the same vascular bed. To test the hypothesis that a site-specific heterogeneity exists in the SMCs of human coronary arteries, we examined the expression of desmin, vimentin, calponin, and high-molecular-weight (h-) caldesmon in arteries of various sizes. Specimens of arteries were obtained at autopsy from 12 patients: 6 adults (67 ± 4 years old); 3 younger adults (26 ± 2 years old); and 3 neonates. The size of the arteries was estimated by the number of SMC layers of the media. The expression was compared in SMCs of large arteries (〉10 layers in adults, 〉5 layers in neonates), medium-sized arteries (5–10 layers in adults, 3–5 SMC layers in neonates), and small arteries (〈3 layers). In adults, the percentage of arteries positive for desmin was lower in the small (17% ± 3%) and medium-sized arteries (44% ± 12%) than in the large arteries (94% ± 6%) (P 〈 0.01). The percentage of arteries positive for calponin was also lower in the small (18% ± 2%) and medium-sized arteries (66% ± 5%) than in the large arteries (100%) (P 〈 0.01). The percentage for vimentin and h-caldesmon did not differ among large, medium-sized, and small arteries. These observations in adults were similar to those in younger adults or neonates. The phenotypes of medial SMCs are vessel sizedependent in human coronary arteries. This finding should be important for understanding the site-specific characteristics of vascular function in the regulation of myocardial perfusion or those of vascular responses to environmental changes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01747855
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  • 158
    Digitale Medien
    Digitale Medien
    Pathological investigation of sentinel lymph nodes (1999)
    Springer
    European journal of nuclear medicine 26 (1999), S. S43 
    Details
    ISSN: 1619-7089
    Schlagwort(e): Key words: Sentinel lymph node ; Frozen section ; Imprint cytology ; Immunohistochemistry ; Polymerase chain reaction ; Flow cytometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract. The sentinel lymph-node procedure enables selective targeting of the first draining lymph node, where the initial metastases will form. A negative sentinel node (SN) predicts the absence of tumour metastases in the other regional lymph nodes with high accuracy. This means that in the case of a negative SN, regional lymph-node dissection is no longer necessary. Besides saving costs, this will prevent many side-effects as a result of lymph-node dissection. The task of the pathologist is to screen SNs for metastases. To this end, several techniques are available such as standard histo- and cytopathological techniques, immunohistochemistry, flow cytometry, and molecular biological techniques. These methods are explained and their sensitivity for detecting SN metastases is discussed. Some of these techniques also appear to be useful for intra-operative evaluation of SNs. The standard protocol for detection of SN metastases consists of extensive histopathological investigation including step H&E stained sections and immunohistochemistry. Intra-operative frozen-section analysis of SNs has been shown to be reliable for breast-cancer axillary lymph nodes. In the intra-operative setting, imprint cytology can also be used but its additional value to frozen section analysis is not yet clear. Further studies are necessary to establish the role of sophisticated molecular biological techniques such as reverse transcription polymerase chain reaction (RT-PCR) in detecting SN metastases. The sensitivity of flow cytometry is too low for this purpose.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002590050577
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  • 159
    Digitale Medien
    Digitale Medien
    Estimation of wound age and VCAM-1 in human skin (1999)
    Springer
    International journal of legal medicine 112 (1999), S. 159-162 
    Details
    ISSN: 1437-1596
    Schlagwort(e): Key words VCAM-1 ; Selectins ; Wound age ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin , Rechtswissenschaft
    Notizen: Abstract To estimate the age of skin wounds, the endothelial adhesion molecule VCAM-1 (CD 106) was detected in paraffin sections after autoclaving and using the ABC technique. The percentage of VCAM-1 positive blood vessels was determined after the blood vessels had been marked with PECAM-1 (CD 31). Low positive staining reactions were observed for VCAM-1 on endothelial cells of uninjured skin in 18% of the samples. In injured skin, 51% of the cases investigated showed a VCAM-1 expression. Strong positive staining reactions were observed 3 h at the earliest and 3.5 days at the latest after the time of injury. The immunohistochemical results for VCAM-1 differed significantly between the injured and uninjured skin (P 〈 0.01). In a few cases VCAM-1 was detected (n = 6) at low intensity in postmortem skin wounds and a moderate to strong expression of VCAM-1 is indicative of the vitality of the wound. The detection of VCAM-1 can be used for estimating the age of wounds in forensic applications if the degree of expression of further adhesion molecules, especially that of selectins, is taken into account.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004140050223
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  • 160
    Digitale Medien
    Digitale Medien
    Structure of the 1 : 1 Complex of Hexakis(2,3,6-tri- O-methyl) α-Cyclodextrin with ( R)-(-)-1,7-Dioxaspiro[5.5]undecane (1999)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 33 (1999), S. 321-330 
    Details
    ISSN: 1573-1111
    Schlagwort(e): crystal structure ; hexakis(2,3,6-triO-methyl)- α-cyclodextrin ; (R)-(-)-1,7-dioxaspiro ; {}[5.5]undecane ; chiral recognition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The crystal structure of the 1 : 1 inclusion complex of hexakis(2,3,6-tri-O-methyl)- α-cyclodextrin (TM αCD) with 1,7-dioxaspiro[5.5]undecane (spiroacetal) is orthorhombic, space group C2221, with a = 24.002(2), b = 14.812(1), c = 21.792(2) Å V = 7747.3(11) Å3 and Z = 8. The molecular six-fold axis of TM αCD coincides with the a two-fold crystallographic axis and the guest is located at the secondary methoxy group side, disordered over two positions related by that axis. The guest model used during the refinement is that of the (R)-enantiomer alone because trials to either refine a 1 : 1 mixture of (R)- and (S)-enantiomers or the (S)-enantiomer alone failed. The crystallographic evidence of enantioselectivity towards the (R)-enantiomer of spiroacetal was confirmed by independent experiments and may be attributed to numerous non bonding interactions between host and guest involving non conventional H-bonds.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008091718896
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  • 161
    Digitale Medien
    Digitale Medien
    No correlation between RET immunostaining and the codon 918 mutation in sporadic medullary thyroid carcinoma (1999)
    Springer
    Langenbeck's archives of surgery 384 (1999), S. 60-64 
    Details
    ISSN: 1435-2451
    Schlagwort(e): Key words Sporadic medullary thyroid carcinoma (sMTC) ; Multiple endocrine neoplasia 2 (MEN 2) ; RET mutation ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Introduction: Medullary thyroid carcinoma (MTC) occurs sporadically or as part of the inherited cancer syndrome, multiple endocrine neoplasia (MEN) type 2. The MEN2 gene has been identified as the RET proto-oncogene. Mutations in the RET proto-oncogene are associated with the pathogenesis of MTC. Approximately 23–40% of sporadic MTCs (sMTCs) have a somatic RET codon 918 mutation within the catalytic core of the tyrosine kinase, which is a mutation found in over 98% of all MEN 2B cases as a germline mutation. Methods: In order to elucidate the role of this mutation, we examined 40 sMTCs for the codon 918 mutation. Simultaneously, we looked for overexpression of the RET protein by means of immunohistochemistry with a newly developed RET antibody. Results: In 8 of 40 tumors (20%), we were able to find a RET codon 918 mutation. Nine of 40 tumors (22.5%) showed immunoreactivity with the RET antibody. Conclusion: The presence of the somatic RET codon 918 mutations did not correlate with the presence of positive RET immunostaining.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004230050175
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  • 162
    Digitale Medien
    Digitale Medien
    Solitary fibrous tumor of the paranasal sinuses (1999)
    Springer
    European archives of oto-rhino-laryngology and head & neck 256 (1999), S. 233-236 
    Details
    ISSN: 1434-4726
    Schlagwort(e): Key words Solitary fibrous tumor ; Paranasal sinuses ; Immunohistochemistry ; CD34 antibodies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Although solitary fibrous tumors are well-recognized in the pleura, their occurrence in the paranasal sinuses is decidedly uncommon. We have encountered two cases of solitary fibrous tumors in the paranasal sinuses and report the clinicopathological findings including CD34 immunoreactivity. One tumor arose in a 55-year-old Japanese businessman and the other in a 53-year-old man who had been in the hospital for schizophrenia for 20 years. The tumors showed characteristic findings. Immunoperoxidase stains on paraffin sections showed staining of the cells for anti-vimentin, but there was no staining for anti-keratin, anti-S-100 protein, anti-desmin, anti-glial fibrillary acidic protein (GFAP), or anti-actin. Anti-CD34 monoclonal antibodies also reacted with these tumors, as those of the pleura generally do, and were found to be useful in diagnosing these tumors.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004050050148
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  • 163
    Digitale Medien
    Digitale Medien
    Immunohistochemical analysis of lymphocytic infiltration in the tumor microenvironment in patients operated on for laryngeal cancer (1999)
    Springer
    European archives of oto-rhino-laryngology and head & neck 256 (1999), S. 384-387 
    Details
    ISSN: 1434-4726
    Schlagwort(e): Key words Laryngeal cancer ; Tumor ; microenvironment ; Immunohistochemistry ; CD lymphocyte ; Infiltration intensity ; Prognostic value ; Lymph node metastases ; Survival time ; Differentiation grade
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The aim of this study was to evaluate semiquantitative and qualitative analysis of lymphocytic infiltrations in a neoplasm microenvironment in patients with laryngeal cancers and the correlation analysis between the intensitivity degree and composition of lymphocytic infiltration in foreseeing a survival time and probability of the appearance of lymph node metastases. Postoperative specimens from 43 patients (Upper Silesia region) operated on for laryngeal cancer in the 2nd ENT Department, Silesian Medical University in Zabrze between 1985 and 1995 all had unfavorable courses due to tumor recurrences. The patients’ ages ranged from 39 to 79 years (mean 57 years). Tissue specimens were subjected to routine processing. The degree of pathological changes was ascertained and immunohistochemical preparations of laryngeal tissue were prepared according to generally accepted methods. The following primary monoclonal antibodies were used: CD 3, CD 20, CD 43, CD 45 RO, CD 56. The distribution analysis of the intensity of the phenotype CD 43 evaluated the lymphocytic infiltration in relation to differentiation of the whole study group. The intensity of CD 43 cell infiltration increased in the group of patients with lymph node metastases. In patients with stage IV disease, a relationship was found between survival time and intensity of cell infiltrations with CD 43 and CD 45 RO lymphocytes. The influence of these two lymphocyte phenotypes in the patient subgroups – one after total laryngectomy with confirmed lymph node metastases and the other group without lymph node metastases – showed their prognostic value. Our analysis of lymphocytic infiltration, mostly of CD 43 cells, in the neoplasm microenvironment indicated a prognostic value for determining a shorter survival time and the possibility of lymph node metastases in patients with recurrences of cancer.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004050050169
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  • 164
    Digitale Medien
    Digitale Medien
    Overexpression of p53 nuclear protein in premalignant and malignant laryngeal lesions (1999)
    Springer
    European archives of oto-rhino-laryngology and head & neck 256 (1999), S. S56 
    Details
    ISSN: 1434-4726
    Schlagwort(e): Key words p53 nuclear marker ; Laryngeal ; hyperkeratosis ; Laryngeal carcinoma ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract To investigate the role of p53 nuclear protein mutations in the initiation and progression of laryngeal carcinoma, 111 premalignant and malignant laryngeal lesions (19 specimens with hyperkeratosis and 92 with carcinoma) were studied immunohistochemically. Overexpression of p53 was observed in 8 cases (42%) of laryngeal hyperkeratosis and 44 cases (47%) of laryngeal carcinoma. However, the expression of p53 showed no relationship to patients’ clinical courses. Our study confirms that p53 overexpression can be found in laryngeal carcinogenesis and is an early event but not a useful prognostic marker.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/PL00014155
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  • 165
    Digitale Medien
    Digitale Medien
    Recent advances in the structure and function of isopenicillin N synthase (1999)
    Springer
    Antonie van Leeuwenhoek 75 (1999), S. 33-39 
    Details
    ISSN: 1572-9699
    Schlagwort(e): active site ; crystal structure ; iron binding motif ; isopenicillin N synthase ; mechanism of action
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Isopenicillin N synthase is a key enzyme in the biosynthesis of penicillin and cephalosporin antibiotics, catalyzing the oxidative ring closure of δ-(L-α-aminoadipoyl)-L-cysteinyl-D-valine to form isopenicillin N. Recent advances in our understanding of the unique chemistry of this enzyme have come through the combined application of spectroscopic, molecular genetic and crystallographic approaches and led to important new insights into the structure and function of this enzyme. Here we review new information on the nature of the endogenous ligands that constitute the ferrous iron active site, sequence evidence for a novel structural motif involved in iron binding in this and related non-heme iron dependent dioxygenases, crystal structure studies on the enzyme and its substrate complex and the impact of these and site-directed mutagenesis studies for unraveling the mechanism of the isopenicillin N synthase reaction.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1001723202234
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  • 166
    Digitale Medien
    Digitale Medien
    QSAR and CoMFA Study of Cocaine Analogs: Crystal and Molecular Structure of (–)-Cocaine Hydrochloride and N-Methyl-3β-(p-Fluorophenyl)Tropane-2β-Carboxylic Acid Methyl Ester (1999)
    Springer
    Structural chemistry 10 (1999), S. 91-103 
    Details
    ISSN: 1572-9001
    Schlagwort(e): x-ray ; crystal structure ; cocaine ; analogs ; QSAR ; CoMFA
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract A QSAR and CoMFA study including 78 cocaine analogs has been completed. These analogs have varied functional groups on the 2β and 3β positions of the tropane ring and include various stereoisomers. The CoMFA program was used to calculate the steric and electrostatic interaction energies as a probe atom or probe charge interacts with the molecules. Shaded contour maps show regions of the cocaine analogs where an increase in bulky substituents is desirable for increased pharmacological activity. The maps also show that small electronegative substituents on the phenyl ring are favored for enhanced activity. The X-ray crystal structures of (–)-cocaine hydrochloride (1) and N-methyl-3β-(p-fluorophenyl)tropane-2β-carboxylic acid methyl ester (2) are reported. These molecules are mostly rigid except for some rotational flexibility in the orientation of the phenyl and benzoyl functional groups. Crystallographic data: (1) C17H21NO4·HCl, orthorhombic space group P212121, a = 7.622(1)Å, b = 10.285(1)Å, c = 21.428(3)Å, Z = 4, final R = 0.035 for 960 observed reflections (I〉3σ(I)). (2) C16H20FNO2, monoclinic space group C2, a = 22.572(7)Å, b = 5.810(1)Å, c = 15.752(4)Å, β = 133.65(2)°, Z = 4, final R = 0.059 for 1511 observed reflections (I〉3σ(I)).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1022029129364
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  • 167
    Digitale Medien
    Digitale Medien
    Crystal Structures of Cs+-Crown Ether Complexes Containing Polynuclear Mercury Iodide Anions (1999)
    Springer
    Structural chemistry 10 (1999), S. 177-185 
    Details
    ISSN: 1572-9001
    Schlagwort(e): Cesium complexes ; crown ethers ; mercuric iodide ; crystal structure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Reactions of CsI and HgI2 with benzo-15-crown-5 (B15C5) and 15-crown-5 (15C5) in an ethanol-acetone mixture produced [Cs(B15C5)2]2[Hg2I6] (1) and {[Cs(15C5)]2[Hg2I6]}n (2), respectively. The structures of the two complexes are quite different. Molar ratios of Cs+ : crown ether are 1 : 2 in 1 and 1 : 1 in 2. Complex 1 consists of two Cs(B15C5) 2 + cations and a Hg2I 6 2- anion. Cs+ lies between the two crown-5 ligands, resulting in a sandwich-type cation. Cationic Cs(B15C5) 2 + and anionic Hg2I 6 2- are linked together by electrostatic interactions and the complex 1 is an ion pair compound. Complex 2 consists of infinite [Cs(15C5)]2[Hg2I6] units. Each structural unit contains two Cs(15C5)+ cations and a Hg2I 6 2- anion. Cs+ is coordinated by five oxygen atoms of 15C5, three iodine atoms of Hg2I 6 2- , and an iodine atom of Hg2I 6 2- in an adjacent structural unit. The interactions between the Cs+ of Cs(15C5)+ and an I− in Hg2I 6 2- from adjacent structural units polymerize the complex 2, resulting in a one-dimensional network structure. The anions of Hg2I 6 2- in both complexes are similar. The two mercury atoms are linked through two bridging iodine atoms and each mercury is also coordinated by two terminal iodines. Crystal data for 1: space group P21/c (No. 14), a = 12.253(4), b = 20.945(7), c = 16.110(6) Å, β = 111.0(1)°, V = 3860 Å3, Z = 4, R = 0.082 (R w = 0.089). Crystal data for 2: space group P21/c (No. 14), a = 12.157(4), b = 8.546(4), c = 20.666(6) Å, β = 91.54(3)°, V = 2146 Å3, Z = 4, R = 0.034 (R w = 0.048).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1021832412700
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  • 168
    Digitale Medien
    Digitale Medien
    Studies on (Hg0.7Mo0.3)Sr2(Sr1−xLax)Cu2Oz with a Wide Range of Doping State (1999)
    Springer
    Journal of superconductivity 12 (1999), S. 403-408 
    Details
    ISSN: 1572-9605
    Schlagwort(e): Superconductivity ; crystal structure ; Hg-based cuprate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik , Physik
    Notizen: Abstract The single-phased series of Sr-bearing Hg-1212 superconducting cuprate,(Hg0.7Mo0.3)Sr2(Sr1−x La x )Cu2O z has been prepared. X-ray diffraction showed that, the obtained samples belong to the 1212-structure with tetragonal space group P4/mmm, similar to that of (Hg, Mo)Sr2(Ca, Y)Cu2Oz, and stabilized in a wide compositional range of 0.25≤x≤0.75. Refinements of the structure are carried out in which the oxygen atoms at the (Hg, Mo) layer is shifted from high-symmetry position (0.5, 0.5, 0) to (x, x, 0). Magnetization and electrical resistivity measurements show that the as-prepared samples exhibit evidence for superconductivity and their superconducting properties were improved after O2 annealing with T onset c as high as 92 K.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1007765718878
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  • 169
    Digitale Medien
    Digitale Medien
    Prognostic value of tumor-associated antigens immunoreactivity and apoptosis in medulloblastomas. An analysis of 73 cases (1999)
    Springer
    Brain tumor pathology 16 (1999), S. 37-44 
    Details
    ISSN: 1861-387X
    Schlagwort(e): Medulloblastoma ; Prognosis ; Tenascin ; Apoptosis ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Medulloblastomas (MB) are the most common central nervous system malignancies in children. Numerous publications describe efforts to identify the predictive value of various patterns of MB pathology and immunohistochemistry, but received data appear to be controversial. Seventy-three patients with cerebellar MB were studied retrospectively. Tumor specimens were immunohistochemically examined with antibodies to various tumor-associated antigens. Also, apoptosis detection by the in situ end-labeling method was performed. Survival analysis was made using univariate and multivariate models. Tenascin immunoreactivity and apoptotic index (AI)〉or=1.5% were found to be closely associated with poor prognosis according to an univariate analysis (P=0.008 and 0.003, respectively). The multivariate Cox proportional hazard model exhibited independent prognostic value for the apoptotic rate only (P=0.023). Tumors with tenascin expression and AI〉or=1.5% significantly prevailed among MB with metastatic dissemination, whereas expression of c-erbB2 oncoprotein and epidermal growth factor receptor was found to be more typical for cases with local tumor recurrence. We came to the conclusion that tenascin immunoreactivity and AI were useful for individual MB prognosis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02478900
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  • 170
    Digitale Medien
    Digitale Medien
    X-Ray Crystal Structure of Four Inclusion Complexes of the Novel Host Gossindane: An Oxidation Product of Gossypol (1999)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 33 (1999), S. 27-38 
    Details
    ISSN: 1573-1111
    Schlagwort(e): X-ray crystallography ; gossindane ; inclusion complexes ; H-bond ; crystal structure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Gossindane, the oxidation product of gossypol, demonstrates inclusion properties towards four solvents chosen accidentally. The crystal data of these complexes with ethanol (I), ethylacetate (II), dichloromethane (III) and water (IV) are: (I): C26H30O6· 2C2H5OH, monoclinic, P2/c, a = 8.687(2) Å, b = 10.986(3) Å, c = 14.778(3) Å β = 110.94° V = 1317 Å3, Z = 2, R = 0.069, N = 1368; (II): C26H30O6· 0.5C4H8O2, monoclinic, P21/c, a = 8.960(2) Å, b = 21.937(5) Å, c = 14.712(3) Å, β = 111.98(2)°, V = 2681 Å3, Z = 4, R = 0.083, N = 2653; (III): C26H30O6· CH2Cl2, monoclinic, P21/c, a = 8.886(2) Å, b = 21.778(6) Å, c = 14.996(4) Å, β = 111.31(3)°, V = 2704 Å3, Z = 4, R = 0.131, N = 1580; (IV): C26H30O6·2H2O, monoclinic, C2/c, a = 29.422(9) Å, b = 6.720(2) Å, c = 27.525(9) Å, β = 117.43(2)°, V = 4830 Å3, Z = 8. R = 0.096, N = 2240. In the solvates H-bonded host molecules form bilayers with very similar structures and a nearly hydrophobic surface. Guest molecules are placed in channels formed between these bilayers and may be H- bonded to host molecules (ethanol). In the hydrate two water molecules using their H-bonding capacity incorporate gossindane molecules into bilayers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008054114773
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  • 171
    Digitale Medien
    Digitale Medien
    Synthesis of Tetra-N-substituted 1,10-dioxa-4,7,13,16- tetraazacyclooctadecanes and their Application as Lead (II) Selective Electrodes. X-ray Crystal Structure of 4,7,13,16-tetrathenoyl-1,10- dioxa-4,7,13,16-tetraazacyclooctadecane (1999)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 33 (1999), S. 135-148 
    Details
    ISSN: 1573-1111
    Schlagwort(e): ion-selective membrane electrodes ; ionophores ; crystal structure ; tetraazacrown ethers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Tetra-N-substituted 1,10-dioxa-4,7,13,16-tetraazacyclooctadecanes (tetraazacrown ethers) (1-5) have been synthesised. Each compound was incorporated in a PVC membrane that provided the basis for a lead-selective potentiometric electrode. The electrode based on the 4,7,13,16-tetrathenoyl-1,10-dioxa-4,7,13,16- tetraazacyclooctadecane (5) ionophore bearing four thenoyl functional subunits exhibited excellent lead (II) ion selectivity with only Ag+ and Hg2+ significantly interfering. The crystal structure of this host (5) has been determined by single crystal X-ray analysis. Crystal data. C32H36N4O6S4, M 700.9, monoclinic, space group P21/c, a, 10.315(4), b, 13.635(2), c, 14.357(6)Å, β 124.63(2)°, V 1661.6(9)Å3, Dc 1.40 g cm-3, Z 2, μ Cu 29.90 cm-1. Final residuals R, Rw were 0.054, 0.082 for the observed data.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008080423071
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  • 172
    Digitale Medien
    Digitale Medien
    Ditopic Calixcrowns with Inequivalent Crown Loops: Synthesis and Structural Characterisation of an Unsymmetrical Calix[4]arene biscrown-6 (1999)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 33 (1999), S. 251-262 
    Details
    ISSN: 1573-1111
    Schlagwort(e): unsymmetrical ditopic calixcrown ; synthesis ; crystal structure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Consecutive base-catalysed reactions of calix[4]arene with the ditosylates of two different polyetherdiols result in the relatively efficient production of an unsymmetrical calix biscrown-6 which, after reduction of an ethoxycarbonyl substituent to an hydroxymethyl group, has been characterised structurally by a room-temperature, single crystal X-ray study of its chloroform solvate. Crystals of ( 4), C53H62O13... ∼0.57CHCl3, are triclinic, P¯1, a 18.95(3), b 12.394(9), c 11.756(7) Å α 106.93(5), β 101.77(8), γ 94.63(8)°, Z = 2; R was 0.088 for 2231 ’observed' (I 〉 3σ(I)) diffractometer data.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008062510582
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  • 173
    Digitale Medien
    Digitale Medien
    Crown Ether-Dinitrile Interaction: An X-ray Study (1999)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 33 (1999), S. 331-338 
    Details
    ISSN: 1573-1111
    Schlagwort(e): dicyclohexano-18-crown-6 ; succinonitrile ; glutaronitrile ; crystal structure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Formation of the host-guest compounds between isomers of dicyclohexano-18-crown-6 as hosts (DC18C6) and various dinitriles as guests has been observed. The structures of two representative compounds (cis-anti-cis-DC18C6...2(NCCH2CH2CN) ( I) and (cis-syn-cis-DC18C6...(NCCH2CH2CH2CN) ( II) were obtained using X-ray diffractometry. Crystal data: ( I) P=¯1, a = 8.586(3), b = 9.324(3), c = 10.714(4) Å α = 72.47(3)°, β = 73.57(3)°, γ = 72.37(3), R1 = 0.034, GooF 1.08, Z = 1; ( II) Pbca, a = 12.881(5), b = 17.887(8), c = 23.042(13) Å, R1 = 0.049, GooF 1.02, Z = 8. Both structures show weak C–-H...O interactions between α-methylene protons of dinitrile guest molecules and oxygen atoms of the macrocyclic host ring.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008092602058
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  • 174
    Digitale Medien
    Digitale Medien
    Solvent Extraction of Perrhenate with 25,26,27,28-Tetrakis[(ethoxycarbonyl)methoxy]-p- tert-Butylcalix[4]arene and Crystal Structure of the Extracted Complex (1999)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 34 (1999), S. 221-233 
    Details
    ISSN: 1573-1111
    Schlagwort(e): extraction ; perrhenate ; calix[4]arene ; crystal structure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The extraction of perrhenate with 25,26,27,28-tetrakis[(ethoxycarbonyl)methoxy]-p-tert-butylcali x[4]arene ( L) into 1,2-dichloroethane was investigated. The presence of Na+ in the aqueous phase is necessary for the extraction. The extraction equilibrium has been established and the thermodynamic quantities ΔH°, TΔS° and log Kex are -61.3 kJ/mol, -41.4 kJ/mol and 3.69, respectively. The effect of diverse ions on the extraction of ReO4- was studied. The corresponding extracted complex [Na L]ReO4.H2O was prepared and characterized by EA, IR and X-ray structure analysis. The complex crystallizes in the tetragonal space group P4ncc with a = b = 14.735(3), c = 29.094(3) Å, V = 6316(2) Å3, Z = 4.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008041507177
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  • 175
    Digitale Medien
    Digitale Medien
    Structure of an Inclusion Compound of 28,28,35,35-Tetramethyl-11-oxo-1,4,18,21-tetraoxa[4,1,4,1,1]paracycloph ane with para-Xylene (1999)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 34 (1999), S. 267-276 
    Details
    ISSN: 1573-1111
    Schlagwort(e): tetraoxaparacyclophane complex ; preparation ; crystal structure ; clathrate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The structure of the 2:3 complex between cyclophane 1 and para-xylene has been determined by a single crystal X-ray diffraction study at 143 K. One para-xylene molecule is enclosed within the cavity formed by two molecules of the host cyclophane; this ensemble displays crystallographic inversion symmetry. The other independent para-xylene molecule is located on a general position in the intermolecular cavities of the crystal lattice. The complex crystallizes in the triclinic space group P(-1) with a = 10β = 89.51(3), γ = 87.26(2)°, and Z = 1. Refinement based on 7539 unique reflections led to a final R(F) value of 0.0609.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008085829837
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  • 176
    Digitale Medien
    Digitale Medien
    Structural Study of C-undecylcalix[4]resorcinarene Solvate with Dioxane (1999)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 35 (1999), S. 131-138 
    Details
    ISSN: 1573-1111
    Schlagwort(e): C-undecylcalix[4]resorcinarene ; crystal structure ; dioxane solvation ; exo molecular complex
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The crystal structure of the molecular complex of C-undecylcalix[4]resorcinarene with dioxane has been determined by X-ray analysis. The asymmetric unit contains one host and four guest molecules. The calix[4]resorcinarene moiety adopts a bowl conformation with C4v symmetry. Four undecyl chains are axially oriented. Calix molecules are packed in a bowl-to-bowl fashion with alternating hydrophilic and hydrophobic layers. One of the ‘hydrophilic’ dioxane molecules is located at the rim of the calix moiety and is hydrogen bonded to the other one. There is no interaction to attract, or direct the dioxane molecule into the interior of the cavity. There is an exo complex formed. The dioxane molecules – located in the hydrophobic part – are highly disordered.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008115002434
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  • 177
    Digitale Medien
    Digitale Medien
    Photochemistry of 9,10-Dicarbonyl-9,10-dihydroanthracene - A Source of 9,10-Dehydroanthracene? (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 57-60 
    Details
    ISSN: 1434-193X
    Schlagwort(e): Benzyne ; Dehydroanthracene ; Matrix isolation ; Photochemistry ; Bergman reaction ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -9,10-Didehydroanthracene (1) is an interesting derivative of p-benzyne that has been subject of several studies. In contrast to an earlier report, the photochemical decarbonylation of 9,10-dicarbonyl-9,10-dihydroanthracene (2) does not lead to 1 but rather to the ring-opened ene-diyne 4. The key intermediate for this reaction is keto carbene 7 which is formed by monodecarbonylation of 2. Carbene 7 is labile towards visible-light irradiation and easily looses the second CO molecule to give 4. Carbene 7 and diyne 4 are characterized by IR and UV/Vis spectra, the IR spectra are compared to calculations at the B3LYP/6-31G(d,p) level of theory.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 178
    Digitale Medien
    Digitale Medien
    Reversal Diastereofacial Selectivity in the n-Butyllithium Addition to O-Protected N-Trimethylsilylimines of (2S)-Lactal: Enthalpic versus Entropic Contributions (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 61-65 
    Details
    ISSN: 1434-193X
    Schlagwort(e): Nucleophilic addition ; Solvent effect ; Reversal of diastereoselectivity ; Temperature effect ; Imines ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -Commonly observed, but rarely explored, is the possibility of modifying the diastereomeric excess (de%) by means of temperature. A complete reversal in the diastereofacial selectivity could be obtained whenever the diastereoisomers concerned are differentially favored by enthalpy and entropy. The enthalpic or entropic dominance of a diastereoisomer depends greatly on the reaction solvent used.
    Zusätzliches Material: 1 Ill.
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  • 179
    Digitale Medien
    Digitale Medien
    Syntheses of Donor-Acceptor-Substituted 2,6-Stellanes (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 73-81 
    Details
    ISSN: 1434-193X
    Schlagwort(e): Donor-acceptor systems ; Cage compounds ; Stelladione ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -A number of condensations could be carried out using tricyclo[3.3.0.03,7]octane-2-one (stellanone, 4) and tricyclo[3.3.0.03,7]octane-2,6-dione (2,6-stelladione, 5) as starting materials. The components for condensations were 2-trimethylsilyl-1,3-dithiane (6), 1,1-bis(trimethylsilyl)-1H-cyclopropa[b]naphthalene (7), its 3,6-dimethoxy-substituted analogue 8, fluorene (12), xanthene (13), diethyl malonate (14), and malononitrile (15). The condensation reactions with 5 yielded mono- and disubstituted products, among them were the donor-acceptor-substituted 2,6-stellanes 33-35. The structures of 18 (prepared from stellanone and fluorene), 19, 24, 27, 31 and 32 (synthesized by condensation of 2,6-stelladione and 2-trimethylsilyl-1,3-dithiane and malononitrile, respectively) were determined by X-ray crystallography.
    Zusätzliches Material: 1 Ill.
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  • 180
    Digitale Medien
    Digitale Medien
    Synthesis of ω-Nitro Acids and ω-Amino Acids by Ring Cleavage of α-Nitrocycloalkanones (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 87-90 
    Details
    ISSN: 1434-193X
    Schlagwort(e): Water ; α-Nitrocycloalkanones ; ω-Nitro acids ; Surfactant ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -The reaction of various α-nitrocycloalkanones 1 with aqueous 0.05 M NaOH, at 80 °C, in the presence of cetyltrimethylammonium chloride (CTACl) as a cationic surfactant, produces ω-nitro acids 2 in good yields. Reduction of the latter with HCOONH4/Pd-C, in methanol, at 80 °C affords ω-amino acids 3. The synthesis of methyl 9-oxodecanoate (8) is also reported.
    Zusätzliches Material: 2 Tab.
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  • 181
    Digitale Medien
    Digitale Medien
    On the Selective O-Alkylation of Ambident Nucleophiles - The Synthesis of Thiohydroxamic Acid O-Esters by Phase-Transfer Reactions (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 97-106 
    Details
    ISSN: 1434-193X
    Schlagwort(e): O-Alkylation ; Ambident nucleophile ; Thiazolethione ; Thiohydroxamic acid ; Phase-transfer reaction ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -O-Alkylation of cyclic thiohydroxamic acids 1 and 3-5 has been studied with a view to developing an efficient method for the synthesis of N-(alkoxy)pyridine-2(1H)-thiones and N-(alkoxy)thiazole-2(3H)-thiones. Four issues have been addressed and the following conclusions can be drawn: (i) Thiones 1 and 5 exist as O-H acids in the solid state. (ii) According to NMR investigations (1H, 13C), the thione structures should be largely retained in CDCl3, [D6]DMSO, and CD3OD solutions of acids 1, 3-5, as is also the case for pyridinethione salts 2a-h. (iii) O-Alkylation of pyridinethione salts occurs in competition with S-alkylation. Selective O-alkylation is however possible, if thiohydroxamate salts with large countercations, such as M = NBu4, are treated with hard alkylating reagents in polar aprotic media. (iv) As tetrabutylammonium thiohydroxamates, such as 2f, are highly useful in the synthesis of cyclic thiohydroxamic acid O-esters, we have developed an efficient protocol for the preparation of N-(alkoxy)pyridine-2(1H)-thiones directly from acid 1 using phase-transfer conditions (alkyl halide or sulfonic acid ester, CH3CN, K2CO3, Bu4NHSO4). This method has proved particularly successful for the synthesis of N-(alkoxy)thiazole-2(3H)-thiones 11, 20-28, which were obtained in yields of up to 87%.
    Zusätzliches Material: 2 Ill.
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  • 182
    Digitale Medien
    Digitale Medien
    Palladium(0)-Catalyzed Asymmetric Synthesis of 1,2,3,4-Tetrahydro-2-vinylquinoxalines (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 129-134 
    Details
    ISSN: 1434-193X
    Schlagwort(e): Tetrahydro-2-vinylquinoxaline ; Cyclization ; Palladium ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -Reaction of (Z)-1,2-bis(methoxycarbonyloxy)but-2-ene (2) with various N,N-bis(arylsulfonyl)-o-phenylenediamines 1 was catalyzed by a palladium complex associated with chiral ligands to give optically active 1,4-bis(arylsulfonyl)-1,2,3,4-tetrahydro-2-vinylquinoxalines 3 with up to 62% ee. The use of (S)-MeOBIPHEP as the chiral ligand and N,N-bis(p-tolylsulfonyl)-o-phenylenediamine (1i) as the nucleophile led to the highest ee at 25 °C, regardless of the solvent used. The enantioselectivity of the cyclization is strongly affected by the nature of the substituents at the nitrogen atom.
    Zusätzliches Material: 4 Tab.
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  • 183
    Digitale Medien
    Digitale Medien
    Stereoselective Synthesis of Enantiomerically Pure β-Fluoroalkyl γ-Butyrolactones by Sulfoxide-Directed Lactonization (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 111-115 
    Details
    ISSN: 1434-193X
    Schlagwort(e): Fluorine ; Lactones ; Annulation ; Ketene ; Sulfoxides ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -Enantiomerically pure α,α-dichloro β-fluoroalkyl γ-p-tolylthio γ-butyrolactones trans-6a-c have been obtained with excellent stereocontrol (〉 98:2) and enantiomeric purity (〉 98:2) by sulfoxide-directed lactonization (Marino's annu-lation reaction) of β-fluoroalkyl vinyl sulfoxides (R)-(E)-5a-c with dichloroketene. Highly chemoselective dechlorination and desulfurization reactions performed on trans-6c efficiently provided the β-chlorodifluoromethyl γ-butyrolactone (S)-8c, the absolute stereochemistry of which was determined by X-ray diffraction analysis of its γ-p-tolylthio precursor (2R,3S)-7c.
    Zusätzliches Material: 1 Ill.
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  • 184
    Digitale Medien
    Digitale Medien
    Reaction of Nitrosobenzene with 4-Methoxy-N-methyleneaniline (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 141-143 
    Details
    ISSN: 1434-193X
    Schlagwort(e): Nitrosobenzene ; 4-Methoxy-N-methyleneaniline ; 1,3,5-Tris(4-methoxyphenyl)-1,3,5-triazinane ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -A 1:1 adduct produced in the reaction of nitrosobenzene (2) with 1,3,5-tris(4-methoxyphenyl)-1,3,5-triazinane (3) has been shown by X-ray diffraction structure analysis to be the N′-(4-methoxyphenyl)-N-phenyl-N-oxyformamidinium species 5.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 185
    Digitale Medien
    Digitale Medien
    A New Diastereoselective Synthesis of anti-α-Alkyl α-Hydroxy β-Amino Acids (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 155-161 
    Details
    ISSN: 1434-193X
    Schlagwort(e): Alkylation ; Oxazolines ; anti-α-Alkyl α-hydroxy β-amino acids ; Lithium dianion ; Penicillin G acylase ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -As part of an ongoing project concerning the synthesis of enantiomerically pure α-hydroxy β-amino acids, we have now developed a general strategy allowing the synthesis of anti-α-alkyl α-hydroxy β-amino acids. Our procedure involves the intermediate formation of trans-oxazolines, which are alkylated at C-5 with good to high diastereoselectivity and then hydrolysed under mildly acidic conditions, affording in quantitative yield the corresponding hydroxy amides. The starting (R)-3-amino-3-phenylpropanoic acid and (S)-3-aminobutanoic acid were obtained in enantiomerically pure form by selective enzymatic hydrolysis of the corresponding phenylacetylamides with penicillin G acylase.
    Zusätzliches Material: 3 Ill.
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  • 186
    Digitale Medien
    Digitale Medien
    Palladium(0)-Catalyzed Reaction of Acidic Anilines with (Z)-2-Butene-1,4-diyl Dicarbonate - Preparation of N-Aryl-4-vinyloxazolidin-2-ones (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 181-186 
    Details
    ISSN: 1434-193X
    Schlagwort(e): Palladium catalysis ; Homogeneous catalysis ; Anilines ; Alkylation ; Oxazolidinones ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -Palladium-catalyzed reaction of acidic anilines with (Z)-2-butene-1,4-diyl dicarbonate affords N-aryl-4-vinyloxazolidin-2-ones. The success of the reaction depends on the acidity of the aniline and requires in situ conversion of the dicarbonate into carbamate carbonate by nucleophilic attack of the aniline conjugate base followed by palladium-catalyzed intramolecular cyclization.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
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  • 187
    Digitale Medien
    Digitale Medien
    Substituent Effects on the Vinylcyclopropane-Cyclopentene Rearrangement - A Theoretical Study by Restricted and Unrestricted Density Functional Theory (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 215-220 
    Details
    ISSN: 1434-193X
    Schlagwort(e): Density functional calculations ; Vinylcyclopropane-cyclopentene rearrangement ; [1,3]-Sigmatropic shift ; Biradical-like transition structure ; Substituent effects ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -The effect of donor substitution by the hydroxy group and of acceptor substitution by the cyano group on the activation energies of the vinylcyclopropane-cyclopentene rearrangement was calculated by the spin-restricted RB3LYP/6-31G* method for reactant structures and by the spin-unrestricted UB3LYP/6-31G* method for transition structures. The activation energies of the rearrangement of hydroxy- and cyano-substituted vinylcyclopropanes are very similar for substitution in the same position. In agreement with earlier findings the substituent effects on the activation energies are closely connected with the radical stabilizing properties of the substituents. As indicated by singlet/triplet splitting energies, the transition structures are essentially biradicaloid. In spite of spin pairing in the transition structure the substituent effects on bond lengths and on stabilization energies are very similar to those of the free radicals corresponding to the two radical substructures. Thus, the transition structures may be considered, in good approximation, as structures consisting of two weakly interacting radicals.Supporting information for this article is available on the WWW under -http://www.wileY-Vch.de/contents/jc_2046/1999/98349_s.pdf or from the author.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 188
    Digitale Medien
    Digitale Medien
    Syntheses and Reactions of 1-Amino-2,2-dialkylcyclopropane-1-carbonitriles and -carboxamides - Potential Precursors of ACC Derivatives (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 239-250 
    Details
    ISSN: 1434-193X
    Schlagwort(e): Cyclopropanes ; Rearrangements ; Cyanohydrins ; Schiff bases ; Small ring systems ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -The direct cyclization of 2-amino-4-chloro-3,3-dimethylbutanenitrile with potassium tert-butoxide in THF afforded 1-amino-2,2-dimethylcyclopropane-1-carbonitrile and a dimerization product. Various new cis- and trans-1-(tert-butylamino)-2-benzyl-2-methylcyclopropane-carbonitriles and© the corresponding cyclopropanecarboxamides have been synthesized, with focus on the isolation of the pure stereoisomeric cyclopropanecarboxamides. The relative configuration of the stereoisomers was established by X-ray crystallographic analysis of one of the model compounds. A new route to the latter functionalized cyclopropanes was developed by reaction of 1-methoxycyclopropylamines with potassium cyanide. Some remarkable rearrangements of 1-aminocyclopropane-1-carbonitriles into azetidine and oxazine derivatives via Favorskii-derived intermediates are reported. Various aspects of the chemistry of geminally functionalized cyclopropanes are discussed.
    Zusätzliches Material: 1 Ill.
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  • 189
    Digitale Medien
    Digitale Medien
    Regio- and Stereoselective Synthesis of Vinylallenes by 1,5-(SN′′)-Substitution of Enyne Acetates and Oxiranes with Organocuprates (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 267-275 
    Details
    ISSN: 1434-193X
    Schlagwort(e): Vinylallenes ; Organocuprates ; Substitution ; Stereoselective synthesis ; Copper catalysis ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -Enyne acetates 2, 4, 6, and 8, as well as enyne oxiranes 10, with different substitution patterns react with organocuprates regioselectively under 1,5-(SN2′′)-substitution to provide vinylallenes 11 and 12. With lithium dimethylcuprate, reduced vinylallenes originating from a (formal) transfer of a hydride ion to the substrate are formed in some cases. The products are usually obtained as mixtures of (E/Z)isomers; however, pure (E)-vinylallenes are formed occasionally. The 1,5-substitutions can also be carried out with catalytic amounts of copper reagents. The reaction of chiral enyne acetate (S)-2a with tBu2CuLi · LiCN proceeds enantioselectively, so that this transformation constitutes a new case of remote stereocontrol.
    Zusätzliches Material: 1 Tab.
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  • 190
    Digitale Medien
    Digitale Medien
    Reactions of the Hydrofluoroborate Salts of Open-Chain Analogues of Reissert Compounds with Some α,β-Ethylenic Esters (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 297-303 
    Details
    ISSN: 1434-193X
    Schlagwort(e): Nitrogen heterocycles ; Open-chain analogue of Reissert compound ; Hydrofluoroborate salts ; α,β-Ethylenic esters ; 1,3-Dipolar cycloaddition ; Azomethine ylide ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -The reaction of the hydrofluoroborate salt of an open-chain analogue of a Reissert compound with some α,β-ethylenic esters does not give a [4 + 2] cycloadduct, as previously described in the case of ethyl acrylate. The reaction starts with a 1,3-dipolar cycloaddition of a münchnone imine 5c, d. The [3 + 2] cycloadducts 13 evolve via a rearrangement-condensation sequence to give a substituted 2-pyridone derivative 18 or 19. The proposed mechanism has been verified by the isolation and structural X-ray analysis of some compounds of the reaction sequence.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 191
    Digitale Medien
    Digitale Medien
    EPC-Synthesis of β-Amino Acid Derivatives through Lithiated Hydropyrimidines (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 335-360 
    Details
    ISSN: 1434-193X
    Schlagwort(e): 2-tert-Butylhydropyrimidinones ; 3-Aminocarboxylic acid derivatives ; Cyclic imino esters ; Lithium enaminates ; Alkylations ; β-Amino acids ; Asymmetric synthesis ; Kinetic resolution ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -Racemic and enantiopure 2-tert-butyltetrahydropyrimidinones (from pivalaldehyde and 3-aminocarboxylic acids) are converted to Alloc-, Boc-, and Z-protected cyclic imino esters (7-10, Schemes 2-4). These are deprotonated to Li enaminates (K, L). Reactions with electrophiles (prim., sec. alkyl, allyl, benzyl, propargyl halides, aldehydes, imines, enoates) give good yields and are highly diastereoselective (products 11-42, Schemes 5-10). A two-step cleavage (removal of protecting group and hydrolysis) under very mild conditions converts the heterocyclic products to α-branched β-amino acid methyl esters (43-61, Schemes 11-13). The structure of the products is determined by NMR spectroscopy (Figure 1), by chemical correlation (Scheme 14), and by X-ray analysis (Figure 2, 3, 7, Table 1). A structure of the Li enaminates is proposed (Figure 4). Mechanistic models are derived for the reactions occurring with formation of two stereogenic centers with relative topicity like (Figures 5, 6).
    Zusätzliches Material: 7 Ill.
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  • 192
    Digitale Medien
    Digitale Medien
    A Unified Synthetic Strategy for the Indolopyridine Alkaloid Group (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 373-378 
    Details
    ISSN: 1434-193X
    Schlagwort(e): Alkaloids ; Cross-coupling ; N-Heterocycles ; Palladium ; Synthesis design ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -Thermal or acetyl chloride induced cyclization of bromoenamide 10 affords the pentacyclic derivative 12 with high yield and regioselectivity. From this common synthetic intermediate, palladium-catalyzed reactions allow the total synthesis of indolopyridine alkaloids 1-6.Supporting information for this article is available on the WWW under -http://www.wileY-Vch.de/contents/jc_2046/1999/98332_s.pdf or from the author.
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  • 193
    Digitale Medien
    Digitale Medien
    Conformational Preferences of Peptides Containing Reverse-Turn Mimetic Bicyclic Lactams: Inverse γ-Turns versus Type-II′ β-Turns - Insights into β-Hairpin Stability (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 389-400 
    Details
    ISSN: 1434-193X
    Schlagwort(e): Reverse-turn mimics ; γ-Turns ; β-Turns ; β-Hairpins ; NMR spectroscopy ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -The solid-phase synthesis and characterization of a series of peptides (3-9), containing reverse-turn mimetic bicyclic lactams (1a, 1b), was reported in the preceding paper. The bicyclic lactams (1a, 1b) possess high structural similarity to the two central residues of a β-turn. The conformational preferences of the constrained peptides have been investigated by NMR spectroscopy and IR spectroscopy. Our experimental results have been complemented by computer modelling studies and show that the constrained peptides (3-9) form an inverse γ-turn or a type-II′ β-turn through intramolecular hydrogen bonding, depending on the nature of the reverse-turn mimic. In N-acetylated tetrapeptide mimics incorporating the two different bicyclic lactams (a series and b series), H5 is available for either a γ-turn (7-membered ring with the carbonyl group of the bicyclic lactam) or a β-turn (10-membered ring with the carbonyl group of residue 2), as shown in Figures 7 and 9. The a series incorporating the (5,7)-bicyclic lactam predominantly induces the γ-turn conformation, while the b series incorporating the (5,6)-bicyclic lactam can promote either a γ-turn or a β-turn conformation, with the β-turn usually being preferred and with varying degrees of β-hairpin formation.
    Zusätzliches Material: 10 Ill.
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  • 194
    Digitale Medien
    Digitale Medien
    Deprotonation of Oxazolinyloxiranes: Formation of Substituted Acyloxiranes (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 409-417 
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    ISSN: 1434-193X
    Schlagwort(e): Deprotonation ; Oxiranyloxazolines ; Oxazolinyloxiranyllithium compounds ; Oxazolidines ; Acyloxiranes ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -Deprotonation of oxazolinyloxiranes 1a, 1h, and 1k with sBuLi/TMEDA at -100 °C in Et2O furnishes oxazolinyloxiranyllithium compounds[1]1b, 1i, and 1l which are stable at low temperature and can be trapped with electrophiles to give substituted oxiranes 1c-1g and 1j. The reaction of 1b with aldehydes produced diastereomers syn (2a-d) and anti (3a-d). Oxiranyllithium 1i from trans-1-(4,4-dimethyl-2-oxazolinyl)-2-p-tolylepoxyethane (1h) was found to be configurationally stable while oxiranyllithium 1l, generated from the cis isomer 1k, was not. Oxazolinylepoxides 1d, 1j, and 1m could be deblocked to acyloxiranes 5a-e through oxazolidines 4a-e.
    Zusätzliches Material: 2 Ill.
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  • 195
    Digitale Medien
    Digitale Medien
    N-Substituted 1-Aminoindoles from Electrogenerated N-Substituted 2-(ortho-Nitrosophenyl)ethylamines (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 419-430 
    Details
    ISSN: 1434-193X
    Schlagwort(e): Electrochemistry ; Electrosynthesis ; Nitrosobenzenes ; Nitrogen heterocycles ; 1-Aminoindoles ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -An electrochemical methodology offering efficient access to N-alkyl- and N-aryl-substituted 1-aminoindoles has been developed. N-Substituted 2-(ortho-nitrosophenyl)ethylamines, electrogenerated in a “redox” flow cell, undergo intramolecular cyclization to hydrocinnoline-type intermediates. Under slightly basic conditions, these undergo spontaneous ring-contraction to produce the N-substituted heterocycles in good yields. The reactions have been studied in slightly acidic and slightly basic aqueous alcoholic media.
    Zusätzliches Material: 11 Ill.
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  • 196
    Digitale Medien
    Digitale Medien
    Synthesis of Enantiopure β- and γ-Amino Alcohols from Homochiral α- and β-Aminoacylsilanes as Stable Synthetic Equivalents of α- and β-Amino Aldehydes (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 437-445 
    Details
    ISSN: 1434-193X
    Schlagwort(e): Aminoacylsilanes ; Amino aldehydes ; Amino alcohols ; Allylation ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -A practical route is described for the synthesis of enantiopure β- and γ-amino alcohols with two stereocenters, starting from homochiral α- (1 and 5) and β- (13 and 16) -aminoacylsilanes, and involving stereoselective addition of allylmetal compounds and subsequent stereospecific protiodesilylation of the adducts. The degree of diastereoselectivity achieved in the nucleophilic addition step depends on both the nitrogen-protecting group and the reagents used. Diastereomeric excess (de) values equal to or higher than 98% were obtained in the TiCl4-promoted allylation of the N-Pht-aminoacylsilanes 1 and 13 and of the N-Ts-aminoacylsilane 5 with allyltrimethylsilane. Lower de values were obtained in the Sc(OTf)3-catalyzed allylation of 5 with tetraallyltin and in the additions of both allyltrimethylsilane and tetraallyltin to the N-Ts-β-aminoacylsilane 16. Protiodesilylation of the adducts, leading to the β- and γ-amino alcohols, was accomplished with TBAF, except in the case of the adducts obtained from 5. For these, a preliminary removal of the tosyl group was necessary, which was accomplished with simultaneous desilylation by treatment with Na in liquid ammonia.Supporting information for this article is available on the WWW under -http://www.wileY-Vch.de/contents/jc_2046/1999/98342_s.pdf or from the author.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
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  • 197
    Digitale Medien
    Digitale Medien
    Diastereoselective Intramolecular meta Photocycloaddition of Side-Chain-Substituted 5-(2-Methoxyphenyl)pent-1-enes (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 463-470 
    Details
    ISSN: 1434-193X
    Schlagwort(e): meta Photocycloaddition ; Photochemistry ; Steric hindrance ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -Irradiation of a series of 5-(2-methoxyphenyl)pent-1-enes substituted with a hydroxy or trimethylsilyloxy group at the α-, β-, or γ-position of the side-chain yields in all cases meta photocycloadducts, in which the configuration at the substituted carbon atom is mainly endo. This indicates that the diastereoselectivity originates from minimization of steric interactions between the side-chain substituent and the ortho-methoxy group at the arene unit. Hydrogen bonding does not seem to be involved. The introduction of the side-chain substituents also influences the regioselectivity of the addition: The linear to angular adduct ratios are significantly increased compared to the case of the parent compound.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
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  • 198
    Digitale Medien
    Digitale Medien
    5-Aza-7-deaza-2′-deoxyguanosine: Oligonucleotide Duplexes with Novel Base Pairs, Parallel Chain Orientation and Protonation Sites in the Core of a Double Helix (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 485-496 
    Details
    ISSN: 1434-193X
    Schlagwort(e): 5-Aza-7-deaza-2′-deoxyguanosine ; Oligonucleotides ; Parallel DNA ; Protonated base pairs ; Tm values ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -Oligonucleotides containing 5-aza-7-deaza-2′-deoxyguanosine (1) were synthesized. Solid-phase synthesis was performed with the phosphonate 15 or the phosphoramidite 5. The amino-unprotected phosphonate 4 was also employed. Hybridization studies of oligonucleotides containing 1 resulted in new base pairs leading to duplexes with parallel (ps) or antiparallel (aps) chain orientation. Among those with parallel chains a stable “purine-purine” base pair was observed between 5-aza-7-deazaguanine and guanine or 7-deazaguanine. Antiparallel stranded duplexes are formed when 5-aza-7-deazaguanine pairs with cytosine. This base pair has only two hydrogen bonds under neutral conditions but is stabilized by a third one in acidic medium. A new base pair is also detected between the base of 1 and isoguanine (neutral medium).
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 199
    Digitale Medien
    Digitale Medien
    Polar and Steric Substituent Effects in 5-exo-trig Cyclizations of 1-Aryl-4-penten-1-oxyl Radicals (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 523-523 
    Details
    ISSN: 1434-193X
    Schlagwort(e): Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -By mistake wrong concentrations were given in the footnote of Table 1 and in the Discussion. Instead of c0 = 1.2 M read c0 = 0.12 M if 2-naphthalenethiol was used as hydrogen donor and instead of c0 = 1.8 M read c0 = 0.18 M if Bu3SnH was used to trap photoproducts. In Table 2 relative rate constants of radical 2d refer to radical 2e and vice versa as correctly stated in the Discussion. In the Experimental Section (Iodocyclization) read 2.25 g (8.86 mmol) of iodine instead of 2.25 g (1.10 mmol) of iodine.
    Materialart: Digitale Medien
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  • 200
    Digitale Medien
    Digitale Medien
    Arylboron Compounds as Acid Catalysts in Organic Synthetic Transformations (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 527-538 
    Details
    ISSN: 1434-193X
    Schlagwort(e): Tris(pentafluorophenyl)borane ; Diarylborinic acid ; Arylboronic acid ; Chiral arylboron catalyst ; Lewis acid ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: -Arylboron compounds, ArnB(OH)3-n (n = 1-3), bearing electron-withdrawing aromatic groups such as triarylboranes, diarylborinic acids, and arylboronic acids represent a new class of air-stable and water-tolerant Lewis acid or Brønsted acid catalysts in organic synthesis. In particular, while tris(pentafluorophenyl)borane has primarily been used as a co-catalyst in metallocene-mediated olefin polymerization, its potential as a Lewis acid catalyst for organic transformation is now much more extensive. Diarylborinic acids and arylboronic acids have shown themselves to be powerful tools in the design of chiral boron catalysts. This article provides a comprehensive summary of the organic transformations catalyzed by arylboron compounds as acids.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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