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  • Polymer and Materials Science  (8)
  • Cardiotoxicity  (2)
  • 1H magnetic resonance imaging  (1)
  • 1
    Digitale Medien
    Digitale Medien
    Calcium dynamics in cardiac myocytes as a target of dichloromethane cardiotoxicity (1996)
    Springer
    Archives of toxicology 70 (1996), S. 158-163 
    Details
    ISSN: 1432-0738
    Schlagwort(e): Key words Dichloromethane ; Cardiotoxicity ; [Ca2+]i transients ; Myocardial contraction ; Cardiac arrhythmia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The purpose of the present study was to determine if cardiac actions of dichloromethane (DCM) in vivo correlate with in vitro alterations of Ca2+ dynamics in cardiac myocytes. Neonatal rat ventricular myocytes were obtained from 2- to 4-day-old rats, and electrically induced fluctuations of cytosolic free Ca2+ concentration ([Ca2+]i) in single cardiomyocytes were investigated using spectrofluorometric analysis of fura-2-[Ca2+]i binding. In cultured myocytes, cumulative exposure to 0.64–40.96 mM DCM resulted in a concentration-dependent and reversible decrease in the magnitude of [Ca2+]i transients with IC10 and IC50 values of 7.98 and 18.82 mM, respectively. Total inhibition of [Ca2+]i transients and cessation of beating were observed at 40.96 mM DCM. Suffusion with DCM for 40 min did not cause morphological alterations of the myocytes. In a urethane-anesthetized rat model, left ventricular pressure was measured by introducing a tip catheter via the carotid artery into the left ventricle, the ECG was recorded by two needle electrodes applied subcutaneously to the chest wall, and arterial pressure was measured via the femoral artery. Oral administration of 3.1–12.4 mmol DCM/kg resulted in DCM blood concentrations between 1.0 and 1.6 mM, accompanied by a dose-dependent decrease in contractile force and heart rate without influencing blood pressure and ECG tracings. Moreover, DCM treatment provided significant protection against arrhythmia development due to CaCl2-infusion. In spite of the slight discrepancy between DCM blood concentrations and in vitro concentrations of DCM for [Ca2+]i transient inhibition, present data are consistent with the view that cardiac effects after DCM exposure are mediated by alterations of Ca2+ dynamics during excitation-contraction coupling.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002040050255
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  • 2
    Digitale Medien
    Digitale Medien
    Cardiotoxicity of chlorodibromomethane and trichloromethane in rats and isolated rat cardiac myocytes (1997)
    Springer
    Archives of toxicology 71 (1997), S. 766-777 
    Details
    ISSN: 1432-0738
    Schlagwort(e): Key words Chlorodibromomethane ; Trichloromethane ; Cardiotoxicity ; [Ca2+] i transients ; Catecholamine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The cardiovascular effects were investigated after acute and subacute treatment with chlorodibromomethane (CDBM; 0.4 to 3.2 mmol/kg p.o.), trichloromethane (TCM; 0.31 and 1.25 mmol/kg p.o.) and mixtures of CDBM and TCM (acute, 0.8 mmol CDBM/kg + 1.25 mmol TCM/kg p.o.; subacute, 0.4 mmol CDBM/kg+0.31 mmol TCM/kg p.o.) in conscious and urethane anaesthetized male Wistar rats (n=610 per treatment). Furthermore it was observed whether cardiovascular responses were modified in CDBM or TCM treated rats after administration of exogenous catecholamines (epinephrine, 1 μg/kg; norepinephrine, 2 μg/kg) and underpinned with in vitro alterations of Ca2+ dynamics in cardiac myocytes. The present findings demonstrated that single and subacute oral administration of CDBM or TCM and mixtures of CDBM and TCM resulted in arrhythmogenic and negative chronotropic and dromotropic effects in conscious and urethane anaesthetized rats. The atrioventricular conduction time and the intraventricular extension time were extended. A slight shortening of the repolarization velocity was observed. The myocardial contractility was depressed and the heart was sensitized to the arrhythmogenic effects of epinephrine. After catecholamine injection the adrenergic cardiovascular responses in urethane anesthetized rats were modified: increased hypertensive epinephrine and norepinephrine action as well as augmentation of negative chronotropic and negative dromotropic cardiac effects of catecholamines were observed. The positive inotropic adrenergic response was diminished. The present in vivo findings, myocardial depression after acute CDBM treatment, as determined by different indices of contractility, correlate well with the observed inhibitory actions of CDBM on Ca2+ dynamics in isolated cardiac myocytes. All cardiovascular alterations found after CDBM or TCM treatment were not intensified after treatment with mixtures of CDBM and TCM. The effects observed were distinctly stronger after TCM (1.25 and 0.31 mmol/kg) treatment compared to CDBM (0.8 and 0.4 mmol/kg) treatment.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002040050459
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  • 3
    Digitale Medien
    Digitale Medien
    31P MR spectroscopy and 1H MR imaging of the human prostate using a transrectal probe (1991)
    Springer
    Urological research 19 (1991), S. 349-352 
    Details
    ISSN: 1434-0879
    Schlagwort(e): Human prostate ; 31P magnetic resonance Spectroscopy ; 1H magnetic resonance imaging
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary 1H magnetic resonance imaging and 31P nagnetic resonance spectroscopy of the human prostate using transrectal surface coild are discussed. 1H MR images were characterized by a high sensitivity, revealing many details in the prostate. Localized 31P spectra acquired during the same investigation showed phosphorous metabolites, which may help differentiate between benign prostatic hyperplasia and prostate carcinoma. An endoscopic transmit-receive radio frequency (RF) antenna is also described which can be used with very low RF power.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00310148
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  • 4
    Digitale Medien
    Digitale Medien
    Radiolysis of polymers of chlorine methacrylates (1988)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 2669-2681 
    Details
    ISSN: 0887-624X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Polymers of α-chloroacrylate (MCA), 1-chloroethyl methacrylate (1CEMA), 2-chloroethyl methacrylate (2CEMA), 2,2,2-trichloroethyl methacrylate (trCEMA) and 1,2,2,2-tetrachloroethyl methacrylate (teCEMA) were γ-irradiated at 77 K. The primary radicals were generated by the abstraction of chlorine. They decay or change into chain end radicals upon warming up to room temperature.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pola.1988.080261004
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  • 5
    Digitale Medien
    Digitale Medien
    Radiation induced radical reactions in poly(chloroalkyl methacrylate)s/triallylisocyanurate mixtures (1989)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 27 (1989), S. 1589-1598 
    Details
    ISSN: 0887-624X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Radical generation after γ-irradiation at 77 K and radical reactions during temperature increase are discussed for the polymers poly(2-chloroethyl methacrylate) and poly(1,2,2,2-tetrachloroethyl methacrylate), mixed with triallylisocyanurate (TAIC). After the radiation interaction radicals are generated in the ester alkyl side groups of the polymer by chlorine abstraction in both polymer/TAIC mixtures. Radical transfer to TAIC occurs during temperature increase to produce allyl radicals. Hence, the high radiation sensitivity of chlorine-containing polymers is combined with the reactivity of allyl radicals of TAIC in such polymer-TAIC mixtures.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pola.1989.080270510
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  • 6
    Digitale Medien
    Digitale Medien
    Experimentelle prüfung der beziehungen zwischen mechanischen konstanten von gelen für dehnung bei konstantem quellungsgrade einerseits, bei konstantem partialdruck des quellungsmittels andererseitsHerrn Prof. Dr. R. SIGNER zum 60. Geburtstag gewidmet (1963)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 62 (1963), S. 40-48 
    Details
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: The YOUNG's modulus E′ and the POISSON number μ′ of a swollen gel sample, stretched in an embedding fluid of constant activity, are different from the YOUNG's modulus E and the POISSON number μ of the same gel sample stretched at constant mass of the swelling agent in the sample. A relation between the four elastic constants derived recently was confirmed by experiment.
    Notizen: Zwei verschiedene Bedingungen, unter denen eine gequollene Folie elastisch verformt werden kann, sind: 1. Dehnung bei konstanter Zusammensetzung, insbesondere bei konstantem Gehalt des Gelfadens an Quellungsmittel und 2. Streckung bei konstantem Partialdruck des Quellungsmittels. Die Elastizitätsmodule E, E′ und die POISSONschen Zahlen μ, μ′ für diese beiden Dehnungsbedingungen werden definiert und experimentell festgestellt. Eine quantitative beziehung zwischen diesen vier Größen, die in einer früheren Arbeit hergeleitet worden war, konnte experimentell bestätigt werden.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/macp.1963.020620105
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  • 7
    Digitale Medien
    Digitale Medien
    Morphologische Besonderheiten polymerer Mehrkomponentensysteme auf der Basis von Dithiolen und Diisocyanaten (1979)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 30 (1979), S. 496-502 
    Details
    ISSN: 0323-7648
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Polyurethanes obtained by reacting mercapto-terminated oligobutadienes, decanedithiol and diisocyanate were investigated by electron microscopy and x-ray scattering. The dependence of the morphological structure on the content of short-chain dithiol is discussed. Heterogeneities in micro- and macroregions were observed, which are caused by crystalline regions and phase separation in chemically different blocks.
    Notizen: Polyurethane auf der Basis von mercapto-terminierten Oligobutadienen, Decandithiol und Diisocyanat werden mittels Elektronenmikroskopie und Röntgenstreuung untersucht. Ihre morphologischen Besonderheiten werden in Abhängigkeit vom Gehalt an Kurzkettendithiol diskutiert. Es treten Heterogenitäten im Mikro- und Makrobereich auf, die durch kristalline Bereiche und Phasentrennung in chemisch unterschiedliche Blöcke bedingt sind.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/actp.1979.010300807
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  • 8
    Digitale Medien
    Digitale Medien
    Strahlungsinitiierter Kettenabbau von Homo- und Copolymeren des 1,2,2,2-Tetrachlorethyl- und Methylmethacrylats (1988)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 39 (1988), S. 405-406 
    Details
    ISSN: 0323-7648
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/actp.1988.010390720
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  • 9
    Digitale Medien
    Digitale Medien
    Löslichkeitsuntersuchungen an Copolymeren aus Styren und Maleinsäureanhydrid durch Trübungstitration (1992)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 43 (1992), S. 124-126 
    Details
    ISSN: 0323-7648
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Turbidimetric titrations of styrene/maleic anhydride copolymers have shown that alcohols precipitate preferably according to molecular weight, whereas hydrocarbons are better suited for separation according to chemical composition. Methanolysis of anhydride units alter perceptibly the precipitation behaviour.
    Notizen: Mittels Trübungstitrationen an Lösungen von Styren/Maleinsäureanhydrid-Copolymeren wurde festgestellt, daß mit Alkoholen als Fällungsmittel bevorzugt nach der Molmasse fraktioniert werden kann, während sich Kohlenwasserstoffe besser zur Trennung nach der chemischen Zusammensetzung eignen. Methanolyse-Reaktionen an den Anhydridbausteinen verändern die Fällbarkeit merklich.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/actp.1992.010430215
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  • 10
    Digitale Medien
    Digitale Medien
    EPR-Untersuchungen γ-bestrahlter chlorsubstituierter Poly(methacrylate) (1987)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 38 (1987), S. 114-119 
    Details
    ISSN: 0323-7648
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: γ-radiolysis of poly(methyl methacrylate) (PMMA) and chlorosubstituted poly(methacrylates) gives radicals with comparable nine-line-EPR spectra. The transformations of the molecules were discussed in light of the quantitative differences in the accumulation processes. EPR-spectra at liquid helium temperatures confirm the hypothesis of allyl radical accumulation in PMMA.
    Notizen: Die im Poly(methylmethacrylat) (PMMA) und in chlorsubstituierten Poly(methacrylaten) radiolytisch erzeugten Radikale ergeben ähnliche EPR-Neunlinienspektren. Molekülumwandlungen zur Deutung der quantitativ unterschiedlichen Akkumulationsprozesse werden diskutiert. EPR-Spektren bei Heliumtemperaturen bestätigen die Hypothese der Akkumulation von Allylradikalen im PMMA.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/actp.1987.010380204
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