digitalis/hypoxia

Incorrect dosage of digitalis occurs frequently and is due in most cases to relative over- or underdosage. The narrow therapeutic range of all cardiac glycosides and the lack of an ideal preparation form the basis, and noncompliance of the ill-informed patient as well as the changing digitalis

The influences of hypoxia and of the interactions of hypoxia with digoxin and ouabain on myocardial stiffness were studied at two extracellular calcium concentrations (2.5 mM and 4.0 mM) in isolated, isometrically contracting cat papillary muscles. Stiffness (delta T/delta L), defined as a change in

Intact, conscious dogs were studied under normal and hypobaric conditions to assess the influence of acute hypoxia on the ability of the animals to tolerate ouabain. Animals were made acutely hypoxic by exposure to hypobaric conditions in a chamber maintained at 446 mm Hg. The ability of the dogs to

The mechanism by which hypoxia abolishes the tachyarrhythmias induced by cardiac steroids was studied in cardiac Purkinje and ventricular muscle fibres. In muscle fibres, hypoxia reduces excitability markedly, reduces the size and increases the time to peak of the oscillatory potentials (Vos) and of

In the isolated rat heart, anoxia or ischemia do not induce important ventricular tachyarrhythmias (VTAs). During the 1st min of reperfusion, VTAs are frequent. The frequency and severity of VTAs during reperfusion depend on the duration and the extent of the myocardial damage. Anoxia abolishes

To investigate the effects of digitalis on chemoreflexes in humans, we measured muscle sympathetic nerve activity (microneurography), minute ventilation, oxygen saturation, end-tidal carbon dioxide, mean arterial pressure, heart rate, and central venous pressure during stimulation of peripheral

The arrhythmogenic and respiratory effects of ouabain during chronic hypoxia were studied in 10 unanesthetized dogs in a hypobaric chamber (446 mmHg) following 7-19 (mean 14.7) days of continuous exposure at this altitude. Another 15 dogs studied at sea level comprised the normoxic control group. In

The effects of hypoxia on the tolerance of myocardium to the toxic actions of digitalis were studied in isolated heart muscle preparations. Perfusion of Langendorff preparations of guinea-pig heart with a hypoxic solution failed to alter Na, K-ATPase with respect to its activity, its sensitivity to

The purpose of this study was to determine whether digitalis glycosides alter the effect of anoxia and reoxygenation on the cardiac myocytes and whether it could be modified by inhibition with amiloride. Cardiac myocytes aggregates were prepared from ventricles of 7 day old chick embryos and were

Endogenous digitalis-like factors (EDLFs) appear to be hypertensiogenic and increased in the serum and placenta of women with preeclampsia (PE), a complication of pregnancy. Digibind, an anti-digoxin antibody Fab fragment, reverses in vitro effects of EDLF and in vivo features of PE. We used

The effects of digoxin and ouabain in 2.5 and 4.0 mM extracellular calcium were studied in well-oxygenated and hypoxic isolated, isometrically contracting cat papillary muscles. Muscle digoxin content was measured at the conclusion of the digoxin experiments. In the well-oxygenated environment

The antiarrhythmic potency of mexiletine was evaluated on three groups of guinea-pig isolated hearts. Arrhythmias were induced (a) with digitalis intoxication, (b) with hypoxia followed by reoxygenation and (c) with ischaemia followed by reperfusion. Mexiletine 10 microM was found to be very

Oxygen limitation of aerobic metabolism is hypothesized to drive organismal thermal tolerance limits. Differences in oxygen availability in air and water may underlie observed differences in upper thermal tolerance of intertidal limpets if oxygen is limiting in submerged environments. We explored