PubMed · 3185244
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
V M Garbuzova. 1988. [Digitalis].. https://pubmed.ncbi.nlm.nih.gov/3185244/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Right ventricular ejection fraction (RVEF), a measure of systolic pump performance of the right ventricle, is frequently depressed at rest or during exercise in patients with chronic obstructive pulmonary disease (COPD). The most common cause of reduced RVEF in COPD is augmentation of right ventricular afterload, namely an increase in pulmonary artery pressure and pulmonary vascular resistance. Therapy with agents that decrease the afterload on the right ventricle have the potential to improve the systolic performance of this chamber. Oxygen, vasodilators such as hydralazine and nifedipine, theophylline, and sympathomimetics all may augment RVEF in part by reducing pulmonary vascular resistance and, in some cases, pulmonary artery pressures in patients with COPD and cor pulmonale. However, only oxygen therapy has been shown to improve survival.
Withering's (1741-1799) greatest merit is not so much that of having discovered the therapeutic value of foxglove in hydropsy, since this indication (among others) was already part of traditional medicine, but actually during a decade of carefully recording clinical observations, he authoritatively settled definite guidelines for its use. In spite of its further utilization in many additional illnesses such as madness, foxglove, and later its main heteroside digitoxine, progressively reached their eventual place in the treatment of supraventricular arrhythmias and in congestive heart failure. In the latter indication, however, its value is now being questioned; it is being accused of augmenting myocardial work due to its vasoconstrictor properties, of favoring dysrhythmic events in a disease already burdened with a 50% arrhythmia mortality, and actually of having a low therapeutic index. Even though being discarded by a number of cardiologists, digitoxine still remains in the appraisal of others as an indispensable medicine.
The preparation of the mono-, bis-, and trisdigitoxosides of 14-hydroxy-5 beta,14 beta-pregnan-20-one and 14,20 beta-dihydroxy-5 beta,14 beta-pregnane by two routes, based on the conversion of the alpha,beta-unsaturated gamma-lactone in digitoxin to the 20-ketone and 20 beta-alcohol by ozonolysis and zinc-acetic acid treatment followed by lithium tri-tert-butoxyaluminum hydride reduction, are described. Synthesis of the alpha-L-rhamnoside derivatives is described also. Structures were confirmed by 1H and 13C NMR spectra. These derivatives show strong interaction with the cardiac glycoside receptor of heart muscle in an [3H]ouabain radioligand binding assay. Structure-activity relationships which are reported for glycosides and genins show that the alpha-L-rhamnoside derivatives are more potent than the beta-D-digitoxoside or the beta-D-glucoside and that the beta-D-glucosides are more potent than the mono-, bis-, and trisdigitoxosides. Potency is not increased by the addition of the second and third digitoxose units.