The effect of graded creatine kinase (CK) inhibition on the response time of mitochondrial O2 consumption to dynamic workload jumps ( t mito) was studied in isolated rabbit hearts. Tyrode-perfused hearts ( n = 7/group) were exposed to 15 min of 0, 0.1, 0.2, or 0.4 mM iodoacetamide (IA) (CK activity = 100, 14, 6, and 3%, respectively). Pretreatment t mito was similar across groups at 6.5 ± 0.5 s...

The anisotropy of frequency-dependent backscatter coefficient, attenuation, and speed of sound is assessed in fresh rat skeletal muscle within 5 h post-mortem. Excised rat semimembranosus and soleus muscles are measured in 37 degrees C Tyrode solution, with the muscle fibers at 90 degrees and 45 degrees orientations to the incident sound beam. Reflected and through transmission signals from eit...

The effect of regulation of mitochondrial dehydrogenase activities on the mean response time of mitochondrial oxygen consumption, which characterizes the delay between changes in ATP hydrolysis and changes in oxygen consumption, was investigated in isolated rabbit hearts and perfused with Tyrode solution at 28 degrees C. Perfusion with ruthenium red (RR) blocks mitochondrial calcium uptake and ...

The effect of lithium ions on cardiac cells was investigated by recording the changes in transmembrane potential and by following the movement of Li, Na, and K across the cell membrane. Isolated preparations of calf Purkinje fibers and cat ventricular muscles were used. Potentials were measured by intracellular microelectrodes; ion transport was estimated by flame photometric analysis and by us...

STRANGE WAYS & FELL (1926) and Dorris (1938) showed that embryonic chick eyes could be cultivated successfully in vitro on plasma clots, and Harrison (1951) and Reinbold (1954) obtained satisfactory results with an agar-tyrode medium containing embryo extract. The retina in these eyes was undifferentiated and, though little or no increase in the size of the eyes occurred, the authors agreed tha...

The objective of this study was to identify cellular electrophysiological mechanisms by which ischemic preconditioning decreases arrhythmias in an isolated ventricular tissue model of ischemia and reperfusion. Electrical activity was recorded with microelectrodes from endocardium and epicardium of paced guinea pig right ventricular free walls. Control preparations were exposed for 15 min to Tyr...

Collagen extending from chordae tendineae sweeps into each tricuspid leaflet in a loose fanlike arrangement merging with the annulus. Each leaflet contains variable amounts of cardiac muscle in continuity with right atrial muscle; valve fibers are sparse, and scattered myofibers and/or bundles of myofibers usually extend only 2-3 mm into the leaflet body. Valve myofibers are structurally identi...

Conduction velocity was increased from 3.5 m/sec to 4.1 m/sec in sheep cardiac Purkinje fibers when the supervising Tyrode solution was changed from 2.7 mM K to 4.0 mM K + . Further increase to 7.0 m n K resulted in a fall in conduction velocity to 3.3 m/sec. To understand the nature of the cellular change responsible for this effect, cable analyses were made. With increases in extracellular K ...

The Corrosion Performances in Various artificial body fluids of various metals are evaluated, Artificial human blood, urine serum, Joint fluid, simulated bile solutions, artificial salaiva, Hank’s solutions Ringers, Tyrode of the solution, Cigada solutions are examined with different type of metals such as Ni-Al-Fe alloys, TiO2 nano tubes, cobalt alloys, Cr alloys, 316 stainless steel, Mg alloy...

AIMS Cardiac arrhythmias are still a major cause of mortality in western countries. Currently available antiarrhythmic drugs are limited by a low efficacy and proarrhythmic effects. The role of the protein kinase C (PKC) signalling pathway in arrhythmogenesis is still unclear. The goal of the present study was to test the effects of PKC stimulation on whole heart electrophysiology and its pro-/...