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  • 1
    Electronic Resource
    Electronic Resource
    The antioxidant defense system of isolated guinea pig Leydig cells (1993)
    Springer
    Molecular and cellular biochemistry 126 (1993), S. 1-7 
    Details
    ISSN: 1573-4919
    Keywords: Leydig cells ; testes ; superoxide dismutase ; catalase glutathione peroxidase ; glutathione ; hydrogen peroxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Utilization of highly enriched preparations of steroidogenic Leydig cells have proven invaluable for studying the direct effects of various hormones and agents on Leydig cell functionin vitro. However, recent work indicates that isolated Leydig cells are often subjected to oxygen (O2) toxicity when cultured at ambient (19%) oxygen concentrations. Because intracellular antioxidants play an important role in protecting cells against oxygen toxicity, we have investigated the intracellular antioxidant defense system of isolated Leydig cells. The cellular levels of several antioxidants including catalase, glucose-6-phosphate dehydrogenase (G-6-PDH), superoxide dismutase (SOD) of the Cu/Zn & Mn variety, glutathione peroxidase, glutathione reductase and total glutathione were quantitated using enriched populations of Leydig cells isolated from adult male guinea pig testes. Compared to whole testicular homogenates, Leydig cells contained significantly (P〈0.01) less G-6-PDH, total SOD, glutathione reductase and total glutathione, but significantly (P〈0.001) more glutathione peroxidase. Compared to hepatic values previously reported in the guinea pig, Leydig cells contain nearly 400 times less catalase, about 14 times less glutathione peroxidase and almost 11 times less glutathione reductase. Since G-6-PDH and glutathione reductase are both necessary to regenerate reduced gluthathione (GSH) which couples with glutathione peroxidase to breakdown hydrogen peroxide (H2O2) under normal conditions, it is plausible that the oxygen toxicity observed in isolated Leydig cells is due to the intracellular accumulation of H2O2. Using the dichlorofluorescin diacetate (DCF-DA) assay, we found that Leydig cells incubated in the presence of 19% O2 produced significantly (P〈0.001) higher levels of H2O2 with time in culture compared to Leydig cells maintained at 3% O2. These results support the hypothesis that the increased susceptibility of isolated Leydig cells to oxygen toxicity may be due, in part, to decreased amounts of certain antioxidant defenses and an increased production of the reactive oxygen species H2O2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01772202
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  • 2
    Electronic Resource
    Electronic Resource
    Impairment of raw 264.7 macrophage function by antiarrhythmic drugs (1994)
    Springer
    Molecular and cellular biochemistry 132 (1994), S. 151-162 
    Details
    ISSN: 1573-4919
    Keywords: antiarrhythmic ; Iidocaine ; quinidine ; procainamide ; oxyradical ; free radicals ; macrophage ; phagocytosis ; respiratory burst ; flow cytometry ; hydrogen peroxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The effect of the antiarrhythmic drugs lidocaine, quinidine and procainamide on macrophage function was investigated in RAW 264.7 mouse monocytic macrophage cell. Cells stimulated by either zymosan or phorbol ester were found to generate both superoxide (O 2 − ) and H2O2. The production of O2 was detected as superoxide dismutase inhibitable ferricytochrome c reduction. H2O2 production was monitored in both chemical and flow cytometric fluorescent assays. Although all three drugs inhibited both O2 and H2O2 release in a dose dependent manner, only quinidine was found to have significant inhibitory effects. The amounts of quinidine required to cause a 50% inhibition in O2 production in zymosan and phorbol ester stimulated cells were found to be 250 μM and 300 μM, respectively and the amounts required to cause one-half optimum levels of H2O2 production in these cells were found to be 50 μM and 100 μM, respectively. The effect of these drugs on O2 producing NADPH oxidase was investigated and only procainamide was found to have a significant effect (p〈0.001) in inhibiting the oxidase activity. Lidocaine and quinidine had no significant effect on the activation of the respiratory burst oxidase. A sensitive and convenient ‘differential phagocytosis’ assay was devised on the basis of number of particles engulfed by individual phagocytes using flow cytometric techniques. It appears to be remarkably free of interference and was applied to investigate the role of antiarrhythmic drugs on the phagocytosis of fluorescent latex beads. All three antiarrhythmic drugs inhibited phagocytosis of latex beads in a dose dependent manner irrespective of the number of particles phagocitized by the cells. The results of these studies do not conclusively establish a mechanism of action of these drugs on the generation of O2 and H2O2 by stimulated macrophages; nevertheless, it is interesting that all three drugs inhibited the phagocytic activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00926924
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  • 3
    Electronic Resource
    Electronic Resource
    Physicochemical properties of (1 → 6)-branched (1 → 3)-β-D-glucans. 1. Physical dimensions estimated from hydrodynamic and electron microscopic data (1993)
    New York : Wiley-Blackwell
    Biopolymers 33 (1993), S. 561-573 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The physical dimensions of several (1 → 6) branched (1 → 3) -β-D-glucan samples obtained from different organisms and their derivatives have been studied by electron microscopy, light scattering measurements, viscometry, and gel permeation chromatography. The electron micrographs indicate that in most samples these biopolymers are adequately described as linear worm-like coils. A sample reconstituted from alkaline media appeared as a blend of the linear, circular, and aggregated polymer morphologies. The average mass per unit length, ML = Mw/Lw for the macroscopically linear samples, was estimated to be 2100 ± 200 g mol-1 nm-1. The parameter mL was determined from the contour lengths obtained by electron microscopy and the molecular weight by light scattering measurements. The observed ML was consistent with the triple-helical structure reported from x-ray diffraction studies and observed degree of side-chain substitution. From the molecular snapshots shown in the electron micrographs, the persistence lengths of these β-D-glucans were determined to be 140 ± 30 nm. The experimentally determined intrinsic viscosities were consistent with these estimates of ML and persistence length. Comparison of the molecular weight distributions obtained from gel permeation chromatography and those deduced from the electron micrographs indicates that number and weight average contour lengths are more reliable than z and z + 1 averages. © 1993 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360330406
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  • 4
    Electronic Resource
    Electronic Resource
    Allylic polymers, 1. Synthesis of polyallyl compounds containing 4-oxycarbonylphthalimido units and their polymers (1975)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 176 (1975), S. 127-141 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Verschiedene polyfunktionelle Allylverbindungen, die 4-Oxycarbonylphthalimid-Grup-pen enthielten, wurden dargestellt, darunter N-Allyl-4-phthalimidcarbonsäure-allylester (3), die N,N′-alkylenbis(4-phthalimidcarbonsäure)-diallylester 8a-c und die Alkylenbis(N-allyl-4-phthalimidcarboxylate) 9a-e und 11.Diese Verbindungen wurden durch Erhitzen mit Dicumylperoxid oder Benzoylperoxid zu vernetzten Harzen polymerisiert, deren thermische Stabilität zunächst durch thermogravimetrische Analyse (TG) untersucht wurde. Die aus 9e und 11 hergestellten Harze zeigten unter Stickstoff bis 390 bzw. 360°C keinen Gewichtsverlust.
    Notes: Various polyfunctional allyl compounds containing 4-oxycarbonylphthalimido units were prepared including allyl N-allyl-4-phthalimidecarboxylate (3), diallyl N-N′-alky-lenebis(4-phthalimidecarboxylates) 8a-c and alkylenebis(N-allyl-4-phthalimidecarboxylates) 9a-e and 11.These compounds were polymerized by heating them in the presence of dicumyl peroxide or benzoyl peroxide to afford network resins. The thermal stability of these resins was preliminarily investigated using thermogravimetric analysis (TG). The resins from 9e and 11 had essentially no weight loss up to 390 and 360°C, respectively, in nitrogen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1975.021760109
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  • 5
    Electronic Resource
    Electronic Resource
    Allylic polymers, 2.Part 1: cf.1. Syntheses of diallyl compounds containing 4-carbamoylphthalimido units and their polymers (1976)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 177 (1976), S. 951-955 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1976.021770333
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  • 6
    Electronic Resource
    Electronic Resource
    Allylic polymers, 3Part 2: cf.2.. Thermally stable thermo-setting resins derived from N-allylphthalimidecarboxylates (1978)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 179 (1978), S. 1361-1364 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1978.021790525
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  • 7
    Electronic Resource
    Electronic Resource
    Novel synthesis of aromatic polysulfides from S,S′-bis(trimethylsilyl)-substituted aromatic dithiols and activated aromatic dihalides (1991)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 29 (1991), S. 1933-1940 
    Details
    ISSN: 0887-624X
    Keywords: new synthetic method ; aromatic polysulfides ; S,S′-bis (trimethylsilyl) dithiols ; aromatic dihalides ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new method for the synthesis of aromatic polysulfides has been developed by the polycondensation of S,S′-bis(trimethylsilyl)-substituted aromatic dithiols with activated aromatic dihalides. The solution polycondensation of three S-silylated aromatic dithiols with bis(4-chloro-3-nitrophenyl) sulfone afforded readily aromatic polysulfides having inherent viscosities of 0.7 dL/g, and the polymerization with bis(4-fluorophenyl) sulfone gave the polymers with viscosity values of 0.3 dL/g. The silylation method was compared advantageously with a conventional route using parent dithiols and activated aromatic dihalides.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1991.080291313
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  • 8
    Electronic Resource
    Electronic Resource
    Liquid chromatographic resolution of enantiomers on chiral amide bonded-silica gel normal phase. Separation of racemic α-amino acid derivatives by N-formyl-L-valyl-aminopropyl-silanized silica (FVA-silica) phase (1979)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 2 (1979), S. 531-532 
    Details
    ISSN: 0935-6304
    Keywords: Liquid chromatography, HPLC ; Enantiomer resolution ; Chiral stationary phase, chemically-bonded ; Enantiomer separation of α-amino acid derivatives by N-formyl-L-valyl-aminopropylsilanized silica (FVA-silica) phase ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240020810
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  • 9
    Electronic Resource
    Electronic Resource
    Mechanism and process of chemomechanical contraction of polyelectrolyte gels under electric field (1990)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 1 (1990), S. 19-25 
    Details
    ISSN: 1042-7147
    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
    Notes: When a water-swollen polyelectrolyte gel is interposed between a pair of electrodes and DC current is applied, the gel undergoes electro-chemomechanical contraction and concomitant water exudation both in water and in the air. In order to clarify the mechanism of the phenomenon, contractile experiments were carried out under various conditions and led to the conclusion that the contraction is essentially associated with electrically driven movement of hydrated micro- and macroions in the gel (electrokinetic process).
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1990.220010104
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  • 10
    Electronic Resource
    Electronic Resource
    Paper form copper ion conductive solid electrolyte (1993)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 4 (1993), S. 194-197 
    Details
    ISSN: 1042-7147
    Keywords: Solid electrolyte ; Copper ion conductor ; Composite ; 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
    Notes: A paper form solid electrolyte (PFSE) with good conductivity and flexibility was developed. PFSE is made of an inorganic-organic composite consisting of a copper ion conductive solid electrolyte of Rb4Cu16I7Cl13 (SE) and a polymer binder embedded in a synthetic fibre network. A PFSE with styrene-butadiene based synthetic rubber (SB) was found to give the highest conductivity among the binding materials that we examined. The SB content was changed from 10 vol% to 90 vol% in the PFSE, and the electrical properties and the damp resistance of PFSE were evaluated. Electrical conductivity decreased slightly with an SB content below 70 vol% and abruptly above 70 vol%. The damp resistance of PFSE improved with the increase of the SB content and was superior to that of the raw powder. The PFSE with 65 vol% SB showed relatively high conductivity, 3 × 10-3 S/cm, which was sufficient for battery use, and good damp resistance.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1993.220040220
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