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  • Cardiotoxicity  (2)
  • Catecholamine  (2)
  • AV sequential stimulation  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Das Verhalten einiger biochemischer Parameter bei der physischen Beanspruchung durch einen der physischen beanspruchung durch einen Langstreckenmarsch (1978)
    Springer
    International archives of occupational and environmental health 41 (1978), S. 103-115 
    Details
    ISSN: 1432-1246
    Keywords: Physical Strain and Stress ; Long-distance March ; Catecholamines ; Glucocorticoids ; Cyclic Nucleotides ; Physische Belastung und Beanspruchung ; Langstreckenmarsch ; Catecholamine ; Glucocorticoide ; cylische Nukleotide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Beanspruchung in Arbeit und Beruf und ihre Auswirkungen auf biochemische Größen stehen seit Jahren zur Diskussion. In vorliegender Studie sollte das Verhalten verschiedener biochemischer Parameter bei physischer Belastung geprüft werden. Wir untersuchten Blut- und Urinproben von 31 Offiziers-anwärten der Bundeswehr vor und unmittelbar im Anschluß an einen Langstrecken marsch von 25 km. Analysiert wurden das Laktat im Vollblut, Noradrenalin, Cortisol und die cyclischen Nukleotide c-AMP und c-GMP im Plasma sowie Adrenalin, Noradrenalin, Vanillinmandelsäure und die 17-Hydroxycorticosteroide im Urin. Signifikante Erhöhungen ergaben sich für die Konzentrationen der Catecholamine und der cyclischen Nukleotide nach der physischen Belastung. Keine signifikanten Abweichungen waren für die Substanzen des Glucocorticoid-Stoffwechsels festzustellen. Die einzelnen Parameter werden hinsichtlich ihrer Relevanz für die Objektivierung physischer Beanspruchung diskutiert.
    Notes: Summary The study presented was performed to evaluate the behaviour of some stress-related biochemical parameters induced by physical stress. We investigated urine and blood samples of 32 graduating officers of the German Bundeswehr before and after a long-distance march over 25 km. The concentrations of lactate in blood, noradrenaline, cortisol and the cyclic nucleotides c-AMP and c-GMP in plasma and adrenaline, noradrenaline, vanillic mandelic acid and 17-hydroxycorticosteroids in urine were determined. Significant elevations were detectable for the concentrations of catecholamines and cyclic nucleotides after the physical work-load. No significant differences were observed for the substances of the glucocorticoid metabolism. The single parameters are discussed in respect to their significance for the objectification of physical strain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00381795
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    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
    Keywords: Key words Dichloromethane ; Cardiotoxicity ; [Ca2+]i transients ; Myocardial contraction ; Cardiac arrhythmia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002040050255
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    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
    Keywords: Key words Chlorodibromomethane ; Trichloromethane ; Cardiotoxicity ; [Ca2+] i transients ; Catecholamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002040050459
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Echokardiografische Optimierung der AV-sequentiellen Schrittmacherstimulation unter verlängerter QT- und Systolenzeit bei ischämischer Kardiomyopathie – eine Fallbeschreibung (1998)
    Springer
    Herzschrittmachertherapie & Elektrophysiologie 9 (1998), S. 286-291 
    Details
    ISSN: 1435-1544
    Keywords: Key words Pacemaker ; AV sequential stimulation ; echocardiographic optimization ; Schlüsselwörter Herzschrittmacher ; AV-sequentielle Stimulation ; echokardiografische Optimierung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Hintergrund: Im Falle einer ausgeprägten Verlängerung der QT-Zeit und Systolendauer bei ischämischer Kardiomyopathie bereitet die echokardiografische Optimierung der AV-sequentiellen Stimulation besondere Schwierigkeiten: Mangels Möglichkeit zur ausreichenden Verkürzung der Systolendauer ist oberhalb einer gewissen Grenzfrequenz, die im vorliegenden Beispiel unter Standard-Stimulationsparametern bei 60/min lag, kein biphasischer transmitraler Einstrom mehr zu erhalten. Methoden: Durch echokardiografisch kontrollierte Optimierung der stimulierten AV-Zeit (SAV) auf einen ungewöhnlich niedrigen Wert (60ms) konnte die Grenzfrequenz auf 75/min. angehoben werden, ein Schrittmachersyndrom mit Pfropfung von Vorhof- und Ventrikelkontraktion galt es hierbei zu vermeiden. Ergebnisse: Durch die Optimierungsmaßnahmen konnte eine Steigerung von Transmitralstrom, Schlagvolumen und Herzminutenvolumen von etwa 15% herbeigeführt und somit erst die hämodynamischen Vorteile der DDD-Stimulation ausgeschöpft werden. Schlußfolgerungen: Bei ausgeprägter Verlängerung der QT-Zeit im Rahmen einer Kardiomyopathie kann die echokardiografische Optimierung der AV-sequentiellen Stimulation die Programmierung einer ungewöhnlich kurzen AV-Zeit erforderlich machen, um eine hämodynamisch optimale Abstimmung zwischen Vorhof und Ventrikel zu erzielen.
    Notes: Background: In case of excessive prolongation of QT time and systolic time interval in ischemic cardiomyopathie serious difficulties in optimating AV sequential pacing by echocardiography may occur. As there are no possibilities to shorten systolic time interval, biphasic transmitral flow can not be achieved beyond a certain limiting heart rate. This rate was found as 60bpm in the following example under standard stimulation parameters. Methods: By using an remarkably short stimulated AV delay (60ms) under echocardiographic control, the limiting heart rate could be elevated to 75bpm, avoiding a pacemaker syndrome at the same time. Results: As consequence of optimization, an increase of transmitral flow, stroke volume, and cardiac output of approximately 15% could be demonstrated and, thus, indicated that the expected hemodynamic advantage of dual chamber pacing could be achieved that way. Conclusions: In case of extreme prolongation of QT time-interval in ischemic cardiomyopathy echocardiographic optimization of AV sequential pacing may require the programming of an uncommonly short AV delay in order to achieve hemodynamic optimal coordination of atrium and ventricle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003990050040
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    Paper (German National Licenses)
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