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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 64 (1995), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The organic molecule K-252a promoted cell survival, neurite outgrowth, and increased choline acetyltransferase (ChAT) activity in rat embryonic striatal and basal forebrain cultures in a concentration-dependent manner. A two- to threefold increase in survival was observed at 75 nM K-252a in both systems. A single application of K-252a at culture initiation prevented substantial (〉60%) cell death that otherwise occurred after 4 days in striatal or basal forebrain cultures. A 5-h exposure of striatal or basal forebrain cells to K-252a, followed by its removal, resulted in survival equivalent to that observed in cultures continually maintained in its presence. This is in contrast to results found with a 5-h exposure of basal forebrain cultures to nerve growth factor (NGF). Acute exposure of basal forebrain cultures to K-252a, but not to NGF, increased ChAT activity, indicating that NGF was required the entire culture period for maximum activity. Striatal cholinergic and GABAergic neurons were among the neurons rescued by K-252a. Of the protein growth factors tested in striatal cultures (ciliary neurotrophic factor, neurotrophin-3, NGF, brain-derived neurotrophic factor, interleukin-2, basic fibroblast growth factor), only brain-derived neurotrophic factor promoted survival. The enhancement of survival and ChAT activity of basal forebrain and striatal neurons by K-252a defines additional populations of neurons in which survival and/or differentiation is regulated by a K-252a-responsive mechanism. The above results expand the potential therapeutic targets for these molecules for the treatment of neurodegenerative diseases.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The protein kinase inhibitor K-252a has been shown to promote cholinergic activity in cultures of rat spinal cord and neuronal survival in chick dorsal root ganglion cultures. To determine the mechanism by which K-252a acts as a neurotrophic factor, we examined the effects of this molecule on a human neuroblastoma cell line, SH-SY5Y. K-252a induced neurite outgrowth in a dose-dependent manner. Coincident with neurite outgrowth was the early tyrosine phosphorylation of 125- and 140-kDa proteins. The phosphorylation events were independent of protein kinase C inhibition because down-regulation of protein kinase C by long-term treatment with phorbol ester did not prevent K-252a-induced tyrosine phosphorylation. Similarly, the protein kinase C inhibitors H7, GF-109203X, and calphostin C did not induce the phosphorylation. We have identified one of the phosphosubstrates as the pp125 focal adhesion protein tyrosine kinase (Fak). Induction of phosphorylation coincided with increased Fak activity and appeared to be independent of ligand/integrin interaction. The induction of Fak phosphorylation by K-252a was also observed in LA-N-5 cells and primary cultures of rat embryonic striatal cells but not in PC12 cells. The protein kinase C-independent induction of tyrosine phosphorylation and the identification of Fak as a substrate of K-252a-induced tyrosine kinase activity suggest that this compound mediates neurotrophic effects through a novel signaling pathway.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The protein kinase inhibitor K-252a increased choline acetyltransferase (ChAT) activity in rat embryonic spinal cord cultures in a dose-dependent manner (EC50 of ∼100 nM) with maximal stimulatory activity at 300 nM resulting in as much as a fourfold increase. A single application of K-252a completely prevented the marked decline in ChAT activity occurring over a 5-day period following culture initiation. Of 11 kinase inhibitors, only the structurally related inhibitor Staurosporine also increased ChAT activity (EC50 of ∼0.5 nM). Effective concentrations of K-252a were not cytotoxic or mitogenic and did not alter the total protein content of treated cultures. Insulin-like growth factor I, basic fibroblast growth factor, ciliary neurotrophic factor, and leukemia inhibitory factor yielded dose-dependent increases in ChAT activity in spinal cord cultures. The combination of K-252a with insulin-like growth factor-l or basic fibroblast growth factor increased ChAT activity up to eightfold over that of untreated controls, which was greater than that observed with each compound alone. K-252a combined with ciliary neurotrophic factor or leukemia inhibitory factor demonstrated no additive or synergistic effects on ChAT activity. These results suggest that there are multiple mechanisms for the regulation of ChAT activity in spinal cord cultures. The enhancement of spinal cord ChAT activity by K-252a and Staurosporine defines a new neurotrophic activity for these small organic molecules and raises the possibility that they may activate some regulatory elements in common with the ciliary neurotrophic factor and leukemia inhibitory factor family of neurotrophic proteins.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Bioactive brain-derived neurotrophic factor (BDNF) and neurotrophin-3 were produced using the baculovirus expression system and purified to homogeneity using ion-exchange and reversed-phase chromatography. Yields of purified neurotrophin-3 (300–500 μg/L) were similar to levels reported for baculovirus-expressed nerve growth factor (NGF), whereas initial yields of BDNF were significantly lower (20–50 μg/L). Improved production of BDNF (150–200 μg/L) was achieved by expressing BDNF from a chimeric prepro-NGF/mature BDNF construct using the Trichoplusia ni insect cell line, Tn-5B1-4. Examination of the distribution of BDNF protein from both the nonchimeric prepro-BDNF and the chimeric prepro-NGF/mature BDNF viruses in Sf-21-and Tn-5B1-4-infected cells suggests a specific deficiency in the Tn-5B1-4 cells in processing the nonchimeric precursor. In addition, the vast majority of the BDNF protein at 2 days after infection was intracellular and insoluble. N-terminal amino acid sequencing of purified recombinant BDNF and neurotrophin-3 demonstrated that the insect cells processed their precursors to the correct N-terminus expected for the mature protein. Bioactivity was characterized in vitro on primary neuronal cultures from the CNS and PNS.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 62 (1987), S. 1274-1277 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The structure of evaporated a-Si/SiOx superlattices has been investigated by transmission electron microscopy, Raman scattering, and optical absorption spectroscopy. The layers are smooth and regular, but all three measurements show effects of bond distortions or defects within 1–2 nm of the Si/SiOx interfaces.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 135 (1966), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochemical Education 22 (1994), S. 12 
    ISSN: 0307-4412
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of oral rehabilitation 17 (1990), S. 0 
    ISSN: 1365-2842
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The histological response of vervet monkey oral epithelium to a negative force similar to that experienced under dentures was investigated. Using impression trays with adherent impressions linked to a vacuum pump, the epithelia of the hard palate, attached gingiva and alveolar mucosa of 16 monkeys were subjected to a continuous vacuum of -80 mmHg, and then fixed by perfusion and immersion while in situ. After processing for light microscopy, sections were measured to obtain the rete peg length, supra-papillary width, epithelial width and basal, spinous and superficial cell density 700 μm−2. Mean values and standard deviations were calculated for each measurement and, using Student's t-test, these data were compared with results obtained for normal tissue from nine additional monkeys. The vacuum caused an increase in epithelial width in the palate and attached gingiva, and a decrease in epithelial width in the alveolar mucosa. The cell density 700 μm−2 decreased significantly in all layers of the palate, but increased in the basal layer of the attached gingiva and the basal and superficial layers of the alveolar mucosa. The alveolar mucosa within 0.5 mm of the mucogingival junction showed a variable response. This study demonstrates that a vacuum of -80 mmHg modifies the structure of the oral epithelium, and this response is directly related to the functional demands of the tissue.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 57 (1954), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Copenhagen : Munksgaard International Publishers
    Journal of oral pathology & medicine 30 (2001), S. 0 
    ISSN: 1600-0714
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The pattern of candidal colonisation was studied in a group of terminally ill patients receiving antifungal treatment for oral candidosis. A total of 43 isolates of C. albicans was collected pre- and post-antifungal treatment from patients up to a maximum period of 4 weeks. Isolates were analysed by electrophoretic karyotyping (EK) and by inter-repeat polymerase chain reaction (IR-PCR). Fifteen electrophoretic karyotypes and 17 IR-PCR profiles were identified. Sequential isolates from 10 patients yielded identical profiles in both EKs and IR-PCR analyses. In the case of four patients, minor differences in the profiles were obtained by either EK or IR-PCR. The findings suggest that antifungal treatment in this patient group fails to eradicate the original C. albicans strain, thereby allowing recolonisation of the oral cavity. The present study has also shown that either EK or IR-PCR is a useful typing approach in such epidemiological investigations.
    Type of Medium: Electronic Resource
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