Since the reaction between urea and diacetyl monoxime was first described (Fearon, 1939) it has formed the basis of most laboratory methods of estimating urea. Many modifications of the technique as originally described have since been suggested in order to try and overcome some of the difficulties of the strongly acid solutions required, light sensitivity of the coloured product of the reactio...

OBJECTIVE In a previous study, initial reperfusion of isolated hearts after cardioplegic arrest with 2,3 butanedione monoxime (BDM) for 5 min was markedly superior to warm hyperkalemic reperfusion in improving the initial oxygen balance and reducing reperfusion arrhythmias. However, left ventricular contractility was only marginally enhanced. The goal of the present study was to test, wether th...

The efficacy of 2,3-butanedione monoxime (BDM) as additive to St. Thomas Hospital II solution (STH) as compared to initial BDM reperfusion with regard to myocardial ischaemia/reperfusion injury was investigated in isolated guinea pig hearts. Isolated guinea pig hearts were perfused with Krebs-Henseleit buffer in the Langendorff technique at constant pressure of 55 mmHg. After cardioplegic arres...

Mechanical properties of the myocardium at end diastole have been thought to be dominated by passive material properties rather than by active sarcomere cross-bridge interactions. This study tested the hypothesis that residual cross-bridges significantly contribute to end-diastolic mechanics in vivo and that changes in end-diastolic cross-bridge interaction parallel concurrent changes in systol...

BACKGROUND/AIMS The zebrafish is an emerging model system for the study of cardiac electrophysiology and human arrhythmias. High resolution imaging techniques are powerful tools for the study of zebrafish cardiac electrophysiology, but these methods require the complete absence of cardiac contraction. Many pharmacological agents that uncouple cardiac contraction also markedly alter the cardiac ...

Physicists have studied the aggregation of adhesive proteins, giving a central role to the elastic properties of membranes, whereas cell biologists have put the emphasis on the cytoskeleton. However, there is a dramatic lack of experimental studies probing both contributions on cellular systems. Here, we tested both mechanisms on living cells. We compared, for the same cell line, the growth of ...

Determination of serum ornithine carbamoyltransferase (EC 2.1.3.3) activity can be a valuable diagnostic tool in the detection of liver diseases involving cytolytic processes. I describe a micromethod for measuring this activity in serum, in which the reaction product, citrulline, is measured colorimetrically in the incubation mixture without prior deproteinization. To eliminate the interferenc...

The agent 2,3-butanedione monoxime (BDM) has been reported to reduce the sensitivity of myofilament force development to calcium ions, without affecting the calcium transient in myocardium. One would predict, therefore, that BDM should reduce the contractile state of the heart without reducing the amount of oxygen that is consumed to fuel the process of excitation-contraction coupling. The purp...

Mechanoelectrical transducer currents in turtle auditory hair cells adapted to maintained stimuli via a Ca(2+)-dependent mechanism characterized by two time constants of approximately 1 and 15 ms. The time course of adaptation slowed as the stimulus intensity was raised because of an increased prominence of the second component. The fast component of adaptation had a similar time constant for b...

The effects of 2,3-butanedione monoxime (BDM) on intracellular Ca2+ transient and cross-bridge function were studied in frog single fibres from the anterior tibialis muscle of Rana temporaria (sarcomere length, 2.2 microm; temperature, 2-4 degrees C). The fluorescent dye fluo-3 was used to monitor the intracellular free calcium concentration ([Ca2+]i) during isometric contractions. BDM (1-5 mM)...