The Relative Importance of Calcium Influx and Efflux via Na-Ca Exchange in Cultured Myocardial Cells

1988 ◽  
pp. 87-95
Author(s):  
William H. Barry ◽  
John H. B. Bridge
Keyword(s):  
Calcium Influx ◽  
Relative Importance ◽  
Myocardial Cells ◽  
Cultured Myocardial Cells

Protective effect of adenosine against a calcium paradox in the isolated frog heart

1992 ◽  
Vol 70 (1) ◽  
pp. 115-120 ◽  
Author(s):  
Maria Touraki ◽  
Antigone Lazou
Keyword(s):  
Protective Effect ◽  
Calcium Influx ◽  
Calcium Paradox ◽  
Mechanical Activity ◽  
Frog Heart ◽  
Dependent Manner ◽  
Myocardial Cells ◽  
Tissue Calcium ◽  
Maximum Protection ◽  
Dose Dependent

The effect of adenosine on the calcium paradox in the isolated frog heart was studied. Addition of adenosine during calcium depletion protected the frog heart against a calcium paradox. This protective effect was indicated by reduced protein and creatine kinase release, maintenance of electrical activity, and recovery of mechanical activity during reperfusion. Tissue calcium determination results showed that adenosine protected frog myocardial cells by reducing the massive calcium influx during reperfusion possibly through an action on calcium channels. Adenosine exerted its action in a dose-dependent manner; a concentration of 10 μM adenosine provided maximum protection of myocardial cells against the calcium paradox damage. Higher concentrations of adenosine produced side effects on both electrical and mechanical activity. These results are discussed in terms of the possible mechanism involved in the protective effect of adenosine.Key words: calcium paradox, adenosine, frog heart.

Improved defibrillator waveform safety factor with biphasic waveforms

1983 ◽  
Vol 245 (1) ◽  
pp. H60-H65 ◽  
Author(s):  
J. L. Jones ◽  
R. E. Jones
Keyword(s):  
Safety Factor ◽  
Voltage Gradient ◽  
Excitation Threshold ◽  
Efficacy And Safety ◽  
Myocardial Cells ◽  
Safety Factors ◽  
Adult Type ◽  
Intracellular Microelectrodes ◽  
Cultured Myocardial Cells

Excitation thresholds and arrhythmias were studied in "adult-type" cultured chick embryo myocardial cells after electric field stimulation with biphasic, truncated, and rectified underdamped RLC (resistance-inductance-capacitance) type waveforms, to test the hypothesis that the negative phase of biphasic waveforms ameliorates membrane dysfunction induced by the initial positive portion. Photocell mechanograms and intracellular microelectrodes monitored extrasystoles and depolarization-induced arrhythmias. Rectifying or truncating biphasic waveforms did not alter the excitation threshold. However, shock intensities producing specific postshock arrhythmias or a specific severity of postshock prolonged depolarization differed significantly when biphasic waveforms were truncated or rectified. The voltage gradient producing a specific dysfunction was 12-14% lower for the truncated version than for the biphasic; that for the rectified version was 17-27% lower than for the biphasic version (although both contained the same energy). Safety factor, the ratio between shock intensity producing specific dysfunction and that producing excitation, was determined for each waveform. Biphasic waveforms had larger safety factors than truncated or rectified waveforms. Since safety factor, as measured in cultured myocardial cells, closely corresponds with in situ defibrillating effectiveness (14), the significantly higher safety factors of biphasic waveforms suggest that carefully shaped biphasic waveforms might improve the efficacy and safety of cardiac defibrillation procedures.

Chronic effects of ethanol on cultured myocardial cells: ultrastructural and morphometric studies

2003 ◽  
Vol 442 (4) ◽  
pp. 356-363 ◽  
Author(s):  
Keiko Mashimo ◽  
Shigeru Sato ◽  
Youkichi Ohno
Keyword(s):  
Myocardial Cells ◽  
Chronic Effects ◽  
Cultured Myocardial Cells

scholarly journals Cytosolic calcium staircase in cultured myocardial cells.

1987 ◽  
Vol 61 (6) ◽  
pp. 934-939 ◽  
Author(s):  
H C Lee ◽  
W T Clusin
Keyword(s):  
Cytosolic Calcium ◽  
Myocardial Cells ◽  
Cultured Myocardial Cells

DNA synthesis by cultured myocardial cells

1967 ◽  
Vol 158 (4) ◽  
pp. 501-507 ◽  
Author(s):  
Ruth E. Rumery ◽  
William O. Rieke
Keyword(s):  
Dna Synthesis ◽  
Myocardial Cells ◽  
Cultured Myocardial Cells
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