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Books reviewed in this article: Stéphane Courtois et al.,The Black Book of Communism: Crimes, Terror, Repression François Furet, The Passing of an Illusion: The Idea of Communism in the Twentieth Century Tony Judt, The Burden of Responsibility: Blum, Camus, Aron, and the French Twentieth Century Michel Dreyfus et al., Le Siècle des communismes. [ABSTRACT FROM AUTHOR]

Reviews the essay 'The Principle of Hope' by Ernst Bloch. Consideration of the overthrow of Communism and Marxist thought; Impact of a socialist society; Debate over the meaning of human history; Lack of a sense of inner hierarchization.

Introduction: Early afterdepolarizations (EADs) can give rise to triggered activity and thereby produce cardiac arrhythmias. We used the whole-cell patch clamp technique to examine the relationship between L-type Ca2+ channel window current and the generation of EAOs in single ventricular myocytes isolated from guinea pig hearts. Methods and Results: With a high concentration of EGTA in the internal solution and Na+-containing physiologic external solution, EADs were induced in undamped cells by injecting intracellular depolarizing current pulses. During voltage clamp protocols designed to simulate action potentials interrupted by EADs, we recorded an inward shift in total current up to 0.7 pA/pF over 400 msec at test steps in the range of the take-off potential for EADs. Cd2+ (0.2 mM) blocked most of the inward shift of current during the test steps and abolished EADs. When the same voltage clamp protocol was used following perfusion with an Na+-free, K+-free external solution, the Cd2+-sensitive inward currents recorded during the test steps were similar to those obtained in physiologic external solution. The overlapping range of potentials for partial activation of the d and f variables of L-type Ca-2+ current ("window" region) measured in Na+-free, K+-free external solution was virtually the same as the voltage range of the Cd2+-sensitive inward currents. Conclusion: Our experiments suggest that: (1) EADs can arise under conditions of high EGTA buffering of intracellular [Ca=2+]; and (2) under these conditions, L-type Ca2+ channel window current plays a major role in the initiation of EADs. [ABSTRACT FROM AUTHOR]

Cardiac hypertrophy is an adaptative process by which the heart accommodates to abnormal pressure and volume overloads. However, hypertrophy of the left ventricle is associated with a high incidence of ventricular arrhythmias and sudden death. The cellular mechanisms responsible for the abnormal rhythmic activity in hypertrophied myocardium has not been clearly defined, but left ventricular hypertrophy is associated with characteristic electrical abnormalities in experimental models and in hypertrophied human tissue. The most consistent electrical alteration is prolonged duration of the action potential in hypertrophied myocardium. The prolonged duration of depolarization predisposes hypertrophied tissue to develop early afterdepolarizations, which can encourage the development of arrhythmias by a variety of mechanisms. Early afterdepolarizations interrupt repolarization and can lead directly to sustained triggered activity. Early afterdepolarizations can depolarize adjacent excitable fibers and thereby induce triggered activity. The prolonged duration of repolarization can enhance influx of calcium, which can in turn lead to delayed afterdepolarizations that can give rise to triggered activity. Early afterdepolarizations can also produce conduction block or delay, which could contribute to the development of reentrant arrhythmias. Early afterdepolarizations are the most likely electrical abnormality to arise from the prolonged time course of repolarization in hypertrophied myocardium. Therefore, therapeutic measures aimed at preventing the development of early afterdepolarizations in hypertrophied myocardium could prove to be a fruitful approach to inhibiting the development of arrhythmias. The development of agents that selectively reduce the duration of the action potential requires a better understanding of the ionic mechanisms responsible for prolonging the action potential in hypertrophied myocardium. In the meantime, avoiding factors known to favor the development of afterpotentials (e.g., extremes of heart rate, electrolyte abnormalities, certain antiarrhythmic drugs) in patients with left ventricular hypertrophy seems prudent. [ABSTRACT FROM AUTHOR]

The early afterdepolarization, which is an interruption of repolarization, can evoke a second upstroke or a salvo of action potentials. It is suggested that the electrophysiological characteristics of the early afterdepolarization can produce a lengthening of the QT interval and that the second upstroke and salvo of activity that may .follow, it can explain many features of torsade de pointes and of certain other ventricular tachycardias. The early afterdepolorization, torsade de pointes, and repetitive monomorphic idiopathic ventricular tachycardia are all induced by bradycardia or by o preceding long RR interal. The R-on-T phenomenon is also discussed. [ABSTRACT FROM AUTHOR]

An essay is presented on the vicissitudes of dialectic in conflict based on the second volume of Jean-Paul Sartre's "Critique de la raison dialectique" and the "Les Aventures de la dialectique," by Maurice Merleau-Ponty. It states that Sartre's book supported Marxism as a philosophy and tool of knowledge. It mentions that a new liberalism was introduced by Merleau-Ponty's work which rejected the principles of Marxism, Communism, and Sartre.

Calcium ions appear to play a central role in the development of ventricular arrhythmias associated with digitalis intoxication. Therefore, the effects of the calcium channel antagonist, verapamil, on ouabain-induced ventricular tachycardia were investigated. Ventricular tachycardia (three or more consecutive wide QRS complexes) was induced in guinea pigs by intravenous infusion of ouabain (1 μg/min) and bursts of rapid ventricular stimulation. Of seven guinea pigs given the infusion of ouabain, all developed ventricular tachycardia at a dose of 82 ± 17 μg/kg (mean ± SD) and none developed heart block or asystole. Eight guinea pigs were treated with verapamil (2 μg/min for 30 minutes) prior to exposure to ouabain. Of those eight animals, only two developed ventricular tachycardia but six developed heart block, or asystole at a significantly higher dose of ouabain (154 ± 47 μg/kg). None of three control guinea pigs given an infusion of normal saline for 90 minutes developed ventricular tachycardia. These results show that pretreatment with verapamil inhibits ouabain-induced ventricular tachycardia in guinea pigs. Combined treatment with verapamil and ouabain is associated with a high incidence of heart block and asystole, which may limit the usefulness of verapamil. [ABSTRACT FROM AUTHOR]

The effects of amrinone on conduction in the intact canine heart were studied. Intracardiac His-electrode catheter recordings were used to measure the functional refractory period (FRP) of the AV node and conduction time through the AV node (A2H2 interval) and in the His-Purkinje system (H2V2 interval). Amrinone (2.5 to 10 mg/kg) shortened the FRP and A2H2 in a dose-dependent manner but had no significant effect on H2V2. In hearts where AV conduction was depressed by treatment with verapamil, propranolol, or ouabain, amrinone partially reversed this depression. Amrinone also shortened the recovery time of spontaneous sinoatrial (SA) node activity following a train of rapid atrial stimulation. This effect was also observed after depression of SA nodal recovery with verapamil, propranolol, or ouabain. These results indicate that amrinone enhances AV conduction and SA nodal activity in the normal heart and may favorably influence depressed AV conduction and SA nodal activity induced by a variety of cardioactive agents. [ABSTRACT FROM AUTHOR]

Reviews Ernst Bloch's 'The Principle of Hope' (1986). Covering a multitude of diverse topics, Bloch offers nothing less than a "hermeneutic for absorbing the entirety of Western culture into Marxism." It is especially concerned with considering 2,500 years of art, literature, behavior, and ideas that express a longing for a better social world. For Bloch all human culture was a single and comprehensible system of hope. Yet his references are so numerous and obscure that few in today's overspecialized culture will be able to follow the book's unleashed erudition. Block, a Stalinist, presents not arguments but a sort of chiliastic enthusiasm that overwhelms the reader.