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  • 11
    ISSN: 1432-0533
    Keywords: Gangliocytoma ; Ganglioglioma ; Ultrastructure ; Immunohistochemistry ; Neuroendocrine markers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We studied five cases of central nervous system neuronal tumor, one gangliocytoma and four gangliogliomas, both ultrastructurally and immuno-histochemically, using antibodies to neuroendocrine markers including tyrosine hydroxylase (TH), serotonin (5HT), somatostatin (SOM), met-enkephalin (MEK), leu-enkephalin (LEK), substance P (SP), gastrin, vasopressin, oxytocin, vasoactive intestinal polypeptide, adrenocorticotropic hormone and calcitonin. In all cases, the presence of dense-core vesicles (60–250 nm) in the neuronal elements was the characteristic ultrastructural finding. Synapses were observed in two cases. Immunohistochemically, variable numbers of neuronal cells showed positive staining for SOM in five cases, TH, MEK and LEK in three cases, and 5HT and SP in one case each. The others were negative. Positive immunoreactivity for multiple markers was shown in all cases. SOM, TH, 5HT and SP were present in the small- to medium-sized cells, while MEK and LEK were almost exclusively confined to the large cells. Our study clearly indicated that these tumors contained neuronal cells which were not homogeneous with regard to neuroendocrine markers.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 288 (1995), S. 24-30 
    ISSN: 1432-069X
    Keywords: Key words G-protein ; Adenylate cyclase ; Phorbol ; esters ; Densensitization ; Keratinocytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Although the protein kinase C (PKC) activator, phorbol 12-myristate 13-acetate (PMA) has been known to induce heterologous desensitization of the epidermal adenylate cyclase, the precise mechanism of PMA action remains unknown. Effects of PMA on the receptor-G-protein-adenylate cyclase system of fetal rat skin keratinocytes (FRSK) were investigated. Choleratoxin catalysed the ADP ribosylation of 45 kDa and 52 kDa membrane proteins and islet activating protein (IAP) catalysed the ADP ribosylation of a 40 kDa membrane protein. Incubation of FRSK with PMA decreased the cholera toxin-catalysed ADP ribosylation of the membrane protein, but not the IAP-catalysed ADP ribosylation. The effect of PMA on the cholera toxin-catalysed ADP ribosylation was inhibited by the PKC inhibitor, H-7 (1-(5-isoquinolinesulfonyl)-2-methyl piperazine dihydrochloride). 1-Oleoyl-2-acetylglycerol (OAG), a membrane-permeable diacylglycerol analogue, also decreased the cholera toxin-catalysed ADP ribosylation, but 4- O -methyl PMA, a very weak PKC activator, had no effect. Keratinocytes are known to express the guanine nucleotide binding proteins, Gsα, Gi2α and Gi3α. Immunoblot analysis of the PMA-treated FRSK showed no detectable difference in the amount of Gsα, Gi2α, Gi3α or the β subunit of the G-protein. PMA significantly decreased the β-adrenergic adenylate cyclase response and cholera toxin-induced cyclic AMP accumulation, while it markedly increased forskolin-induced cyclic AMP accumulation. These results indicate that phorbol esters affect the stimulatory guanine nucleotide binding protein (Gs) of FRSK via a PKC-dependent pathway.
    Type of Medium: Electronic Resource
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  • 13
    ISSN: 1432-2307
    Keywords: c-KIT ; Immunohistochemistry ; Malignant transformation ; Melanocyte ; SCF
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In order to characterise the distribution and role of stem cell factor (SCF), a recently-reported growth factor for normal melanocytes, we carried out an immunohistochemical study on benign and malignant melanocytic tumours with a comparison with the presence of its receptor c-Kit proto-oncogene product (c-KIT). In normal skin, SCF was mainly observed in endothelial cells of blood vessels but not frequently in basal melanocytes, whereas c-KIT was predominantly localised in tissue mast cells. In benign neoplastic melanocytes (common melanocytic naevi), localisation of SCF and c-KIT was complementary: SCF was mostly found in dermal naevus cells while c-KIT was revealed in epidermal naevus cells, although the expression of the latter antigen was not frequent. Malignant melanoma cells showed less frequent expression of these antigens than those in benign lesions. Of five cultured melanoma cell lines, SCF was observed in only one, and c-KIT was not found in any melanoma cells. No quantitative or qualitative alterations assessed by Western blot analysis were induced in the presence of phenotypic modifiers (sodium butyrate and HMBA). Present data suggest that loss of SCF expression in neoplastic melanocytes is commonly associated with malignant transformation of pigment cells rather than loss of its receptor c-KIT.
    Type of Medium: Electronic Resource
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  • 14
    ISSN: 1617-4623
    Keywords: Key words cAMP level ; Adenylate cyclase ; CRP ; Phosphorylation state ; IIAGlc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The cellular cAMP level is markedly down-regulated by cAMP receptor protein (CRP) in Escherichia coli. CRP regulates adenylate cyclase both at the level of transcription of its structural gene cya and at the level of enzyme activity. We established a method to determine the phosphorylation state of IIAGlc, the glucose-specific phosphotransferase protein, in intact cells. We found that IIAGlc exists predominantly in the unphosphorylated form in wild-type cells growing in LB medium, while it is largely phosphorylated in crp or cya cells. Disruption of the ptsG gene that codes for the membrane component of the major glucose transporter (IICBGlc), and/or the fruF gene coding for FPr (fructose-specific hybrid phosphotransferase protein), did not affect the phosphorylation state of IIAGlc. When IICBGlc was overproduced in the presence of glucose, the levels of both cAMP and phosphorylated IIAGlc in crp cells were concomitantly decreased to wild-type levels. In addition, when His-90 in IIAGlc was replaced by glutamine, both phosphorylation of IIAGlc and the overproduction of cAMP in crp cells were eliminated. We also found that extracts of crp + cells markedly stimulate dephosphorylation of IIAGlc-P in vitro. We conclude that CRP-cAMP down-regulates adenylate cyclase primarily by reducing the level of phosphorylated IIAGlc. The data suggest that unspecified proteins whose expression is under the control of CRP-cAMP are responsible for this regulation.
    Type of Medium: Electronic Resource
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  • 15
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 2839-2847 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 16
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 70 (1998), S. 659-669 
    ISSN: 0020-7608
    Keywords: Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A procedure for the calculation of molecular properties in the full quantum mechanical treatment is presented. We formulate the non-Born-Oppenheimer density functional theory and propose its numerical scheme. We numerically calculate the energy, particle densities, interparticle distance, and (hyper)polarizability of the hydrogen molecule and its isotopes using this method and discuss isotope effects on the physical properties.   © 1998 John Wiley & Sons, Inc. Int J Quant Chem 70: 659-669, 1998
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 17
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 1618-1622 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: For an ester-type photosensitive polyimide precursor of low thermal expansion coefficient, the oxygen concentration in the curing process and the molecular weight of the polyimide precursor were found to control the properties of the polyimide. The effects of these factors on the thermal expansion coefficient, tensile strength, and modulus of polyimide film were investigated. Based on these results, a photosensitive polyimide with low thermal expansion coefficient, called the PIMEL TL-series, was developed. Crack and delamination free multilayers were successfully achieved using this newly developed product.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 18
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 29 (1991), S. 1419-1425 
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Time-resolved light scattering was employed to investigate kinetics of phase separation in mixtures of poly (ethylene glycol monomethylether) (PEGE)/poly (propylene glycol) (PPG) oligomers. Phase diagrams for PEGE/PPG of varying molecular weights were established by means of cold point measurements. The oligomer mixtures reveal an upper critical solution temperature (UCST). Several temperature quench experiments were carried out with a 60/40 PEGE/PPG blend by rapidly quenching from a single phase (69°C) to two-phase temperatures (66-61°C) at 1°C intervals. As is typical for oligomer mixtures, the early stage of spinodal decomposition (SD) was not detected. The kinetics of phase decomposition was found to be dominated by the late stage of SD. Time-evolution of scattering intensity was analyzed in accordance with nonlinear and dynamical scaling theories. The time dependence of the peak intensity Im and the corresponding peak wavenumber qm was found to follow the power-law {Im(t)˜ tα, qm(t)˜ t-β} with the values of α = 3 ± 0.3 and β = 1 ± 0.2, which are very close to the values predicted by Siggia. This process has been attributed to a coarsening mechanism driven by surface tension. In the temporal scaling analysis, the structure function reveals university with time, suggesting self-similarity. Phase separation dynamics in 60/40 PEGE/PPG resembles the behavior predicted for off-critical mixtures.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 19
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 22 (1978), S. 1607-1618 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Membranes were dynamically formed from poly(acrylic acid), poly(1-methyl-2-vinylpyridinium iodide), and methylcellulose on a Millipore filter. The effects of the conditions of membrane formation on reverse osmosis performances and the membrane structure were investigated. The primary factors that affect membrane performance were ascertained to be the kind and concentration of salts and the pH of the preparing solutions, the concentration and the polymerization degree of the membrane materials, the pore size of filters, and the pressure and circulation velocity during membrane formation. Two types of dynamically formed membranes, the membranes inside the filter and the membranes on the filter, were distinguished.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 20
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 22 (1978), S. 2609-2620 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Reverse osmosis of some aromatic compounds in 1-propanol solution using porous cellulose acetate membranes and some factors which influence the organic solute permeability were investigated. Reverse osmosis data for a number of benzene derivatives showed that only phenol was rejected and the others were enriched. For the compounds with various substituent groups, the solute permeabilities have the following order; OH 〈 CH3 〈 H 〈 Cl 〈 NH2 〈 NO2. In the series of benzene, naphthalene, and anthracene, the permeability is related to the molar volume of solutes and varied as follows: benzene 〈 naphthalene 〈 anthracene. Generally speaking, there are two factors - a partition coefficient and a diffusion coefficient - for governing the permeation behavior through the membrane. Under the condition that no steric effect is exerted, the partition coefficient exclusively is a dominant factor. A good correlation between the partition coefficient of a particle and that of the membrane was pound. The partition coefficients are closely related to the dipole moment of solutes.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
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