Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0018801 (heart failure)
 72,216 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previously, we reported that amrinone increases isometric twitch force but relaxes K+-induced contracture in muscles from normal cat right ventricle. This study evaluated its effects on diseased cardiac tissue. Right-ventricular papillary muscles were obtained from cats with subacute right-ventricular failure (3-14 days after partial pulmonary-artery ligation) and studied in vitro during stimulation (0.5 Hz) and exposure to high-K+ Tyrode solution. Active isometric twitch force and rate of force development (dP/dt) were significantly lower in muscles from hearts with right-ventricular failure compared to control muscles. In addition, while time to peak force was not different, duration of the twitch was significantly longer. In contrast to its positive inotropic actions in control muscles, amrinone (5.3 X 10(-4) M) had no significant effects on twitch force and dP/dt in muscles from failed ventricles. Time to peak force was not changed by amrinone in either group, but unlike its action in control muscle, duration of the twitch was reduced in failed muscle. Amrinone reduced K+-contracture force similarly in both control and failed muscles. Isoproterenol (10(-6) M) significantly increased twitch force and dP/dt and reduced K+-contracture force in both muscle groups. Since amrinone appears to be a phosphodiesterase inhibitor, our data indicate that cyclic AMP (cAMP)-related relaxation processes, but not cAMP-related contractile processes, can be enhanced by phosphodiesterase inhibitors in experimental heart failure. Furthermore, amrinone's reduced positive inotropic effect in failed myocardium suggests that its improvement of ventricular function in patients reflects, in part, enhancement of relaxation.
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PMID:Enhanced relaxation and reduced positive inotropic effects of amrinone in ventricular muscle from cats with subacute heart failure. Implications for drug therapy. 298 64

Hydralazine is a potent arteriolar dilator, which increases cardiac output in patients with heart failure. Previous studies suggested that these beneficial effects might be due in part to a positive inotropic effect. The present study further investigated the effect of hydralazine on myocardial contractility and adenyl cyclase activity. In isolated cat papillary muscles, bath concentrations of hydralazine up to 10(-4) mol X litre-1 did not alter force development, whereas 10(-3) mol X litre-1 hydralazine increased isometric force by 31%. This effect was blocked by 10(-6) mol X litre-1 propranolol and was absent after catecholamine depletion produced by previous reserpine treatment. In canine ventricular myocardium hydralazine in all concentrations used (10(-7) to 10(-3) mol X litre-1) increased control adenyl cyclase activity. This increase was statistically significant in 10(-6) to 10(-3) mol X litre-1 concentrations, reaching a maximum of 69.5% at 10(-4) mol X litre-1. In cat ventricular myocardium 10(-6) to 10(-3) mol X litre-1 hydralazine increased the cyclic AMP production, although to a lesser magnitude than that in canine tissue. Hydralazine 10(-5) mol X litre-1 produced a 37.8% increase, and the maximum effect of 45.2% occurred at 10(-3) mol X litre-1. The positive effects of hydralazine were completely abolished by the addition of propranolol in dogs as well as in cats. Thus the adenyl cyclase stimulation induced by hydralazine is mediated through the beta receptor.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Correlation between effects of hydralazine on force and on the adenyl cyclase system of ventricular myocardium in dogs and cats. 301 Dec 68

The effects of the benzimidazole-pyridazinone pimobendan (UD-CG 115 BS) on systemic haemodynamics, myocardial performance and the distribution of cardiac output were studied in open-chest anaesthetized pigs. After intravenous bolus injections (0.1-0.5 mg X kg-1, n = 7) increases in heart rate (up to 37%), LVdP/dtmax (up to 54%) and decreases in systemic vascular resistance (up to 33%) and left ventricular filling pressure (up to 50%) were observed, while cardiac output was unchanged. Vasodilation occurred in nearly all regional vascular beds, but was most pronounced in the adrenals (200%), followed by stomach (150%), small intestines (130%), heart (125%) and brain (110%). O2-consumption was not affected in spite of the increases in heart rate and myocardial inotropy. To evaluate the direct effects on the myocardial, pimobendan was also infused (1-5 micrograms X kg-1 X min-1, n = 7) directly into the left anterior descending coronary artery. In addition to a marked vasodilation of the coronary bed (140%), also a lowering of the left ventricular filling pressure (up to 20%) and cardiac output (15%) was observed, but no changes in regional myocardial function, LVdP/dtmax and systemic vascular resistance occurred. Immediately after intracoronary bolus injections (1 mg X kg-1, n = 4), vasodilation of the coronary vessels was apparent, but myocardial contractility was not affected. This may explain that cyclic AMP content, determined in biopsies excised 30 s after injection, was unaltered. It may be concluded that pimobendan exerts actions on the cardiovascular system which may be useful in the treatment of heart failure.
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PMID:Usefulness of pimobendan in the treatment of heart failure. 303 12

To examine the interrelationship between human atrial natriuretic polypeptide (hANP) and cyclic 3'5'-guanosine monophosphate (cyclic GMP), plasma concentrations of these compounds were determined in 61 disease-free humans, as controls, and in 35 patients with congestive heart failure. Levels of plasma hANP (199.6 +/- 53.7 pg/ml) and cyclic GMP (12.6 +/- 1.7 pmol/ml) in patients with congestive heart failure were significantly higher than in the control subjects (hANP 57.1 +/- 2.8 pg/ml, cyclic GMP 5.2 +/- 0.3 pmol/ml). Although plasma hANP concentrations in the patients with congestive heart failure tended to increase with the severity of cardiac dysfunction, there was no significant correlation between the levels of plasma hANP and the grade of heart failure, classified according to the New York Heart Association. However, a significant correlation was found between plasma hANP and cyclic GMP concentrations in both the healthy subjects and the patients with congestive heart failure, and a weak positive correlation between plasma hANP and cyclic 3'5'-adenosine monophosphate (cyclic AMP) concentration in the patients with congestive heart failure. Thus, changes in plasma cyclic GMP concentration depend to some extent on the plasma concentrations of hANP.
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PMID:Relationship between atrial natriuretic polypeptide and cyclic 3'5'-guanosine monophosphate in human plasma. 303 37

The effects of the rapid infusion of large doses of dibutyryl cyclic AMP (DBcAMP) were studied to clarify the clinical usefulness of its vasodilating action in 32 middle-aged patients, who underwent various types of surgery and developed systolic hypertension of over 160 mmHg during general anaesthesia. DBcAMP was given i.v. with an infusion pump at a rate of 0.6 mg kg-1 min-1 for 20 min. In all patients just after the infusion, systolic arterial pressure decreased from 174.0 +/- 20.7 to 129.0 +/- 23.9 mmHg, diastolic pressure decreased from 93.1 +/- 13.4 to 64.8 +/- 13.3 mmHg, heart rate increased from 81.2 +/- 15.7 to 91.5 +/- 19.5 beats min-1, and urine volume increased from 69.4 +/- 54.8 to 182.7 +/- 143.5 ml h-1. In three patients, cardiac index increased from 3.44 to 4.24 l min-1 m-2. In seven patients, tachycardia exceeding 120 beats min-1 developed. DBcAMP was also effective in patients with a history of hypertension. The strongest antihypertensive effect was observed in patients anaesthetized with nitrous oxide-oxygen and enflurane. We speculate that DBcAMP is useful to control hypertension and may be particularly indicated in patients with cardiac failure, renal disorders and essential hypertension.
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PMID:The control of hypertension with dibutyryl cyclic AMP. 303 96

A large number of chemical substances increase contractility of isolated animal myocardial preparations. Their augmentation is the result of a number of mechanisms which ultimately increase the available calcium for contractile protein coupling. Although there is some research with drugs which activate calcium channels, present clinical research is mainly confined to agents whose major action on contraction is mediated by an increase in myocyte cyclic AMP. Species and age variations in the inotropic effect are common. These agents have additional cardiac effects (e.g. chronotropic, lusitropic) and non-cardiac actions. They are potent vasodilators. In isolated human myocardium obtained from patients without heart failure, they increase contractility at high concentrations. Generally this effect is attenuated in isolated myocardium obtained from patients and animals with chronic cardiac failure. In myocardium from patients with the most severe heart failure, even very high concentrations fail to increase contractility. Part of this attenuation may be due to reduced receptor number (or sensitivity) when the drug's effect is due to receptor-coupled adenylate cyclase activation. However, a reduced ability to produce and/or respond to cyclic AMP itself is suggested by impaired responses to phosphodiesterase inhibitors. In vivo, these agents have frankly harmful effects in patients with near normal cardiac function. Despite increasing contractility indices, they lower blood pressure, raise heart rate and impair myocardial lactate metabolism without increasing cardiac output. In patients with severe heart failure they produce beneficial resting haemodynamic changes; increased cardiac output and reduced filling pressures with only small changes in blood pressure and heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:New positive inotropic substances--true inotropy or peripheral effects? 306 33

Changes in compartmentation and specific mechanism in acute myocardial failure due to global ischemia and in regional myocardial ischemia in dog hearts are described. Ischemic failure was produced by periodic arrest of flow to supported heart preparations perfused with a fluorocarbon (FC-43). Sarcolemmal vesicles (SL) prepared from ischemic failing heart preparations exhibited diminished Ca++ binding and phosphorylation. TA-064, a beta-1-agonist partially abolished the reduction in Ca++ binding and phosphorylation of SL vesicles. The addition of cyclic-AMP (cAMP) and of protein kinase (PK) increased phosphorylation of SL vesicles obtained from non failing heart preparations. Combination of cAMP and of PK had the greatest effect. In contrast to myocardial failure, myocardial infarction is known to produce a large variety of specific disturbances in intermediary cardiac metabolism. Apparently in ischemic failing heart preparations, Ca++ binding and phosphorylation by SL are deficient. The results with TA-064 and isoproterenol suggest that phosphorylation of SL may play a role in the positive inotropic effect of beta-1-agonists.
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PMID:Compartmentation and functional mechanisms in myocardial failure and myocardial infarction. 352 63

Clinical trials with new inotropic, non-adrenergic agents with vasodilating properties have open new perspectives for the treatment of acute and chronic heart failure. If their mechanism of action is not exactly known, they are likely to increase C.AMP by phosphodiesterase inhibition. A clear distinction has to be made concerning short- and long-term administration of these drugs. Amrinone (A) has been administered to 10 patients with low postoperative cardiac output as unique inotropic therapy and to 34 patients in severe cardiogenic shock, despite optimal treatment. In the latter group, A was added to the preliminary drugs. In both groups of patients, hemodynamics improved significantly, except in 4 patients in group II, who died. Except in one case with thrombocytopenia and one with supraventricular dysrhythmias, no serious side-effects were noted. No long-term treatment has been carried out in our institution. The literature has widely reported that the new inotropic drugs used in class III and IV patients, are likely to increase patient's well-being and exercise capacity, but not life expectancy.
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PMID:New inotropic-vasodilating drugs in acute and chronic heart failure. 376 91

There is a decrease in total adenine nucleotides, cyclic AMP (cAMP), ATP/total ADP, and phosphocreatine (PCr)/creatine (Cr) both in situ and in the perfused heart in the heart failure stage of the cardiomyopathic Syrian hamster. There were decreases in developed pressure, dP/dt, and O2 consumption associated with the decrease in total adenine nucleotides and cAMP. Cardiomyopathic Syrian hamsters (180-240 days old) with congestive heart failure were given water with the calcium entry blocker, verapamil, as an additive 2 mo before death. In the cardiomyopathic group given verapamil the adenine nucleotides, cAMP, and high-energy phosphates were preserved and cardiac performance was not significantly different from that of the verapamil-treated healthy hamsters at the time of death. Pretreatment of cardiomyopathic animals with verapamil (6.6 mg verapamil/ml water consumed by drinking) resulted in significantly higher ATP/total ADP and PCr/Cr compared with nontreated cardiomyopathic hamsters. This is the first report demonstrating that a calcium entry blocker may improve cardiac performance and preserve total adenine nucleotides during the heart failure stage of the cardiomyopathic hamster.
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PMID:Verapamil preserves adenine nucleotide pool in cardiomyopathic Syrian hamster. 394 35

Compounds with phosphodiesterase inhibitory activity stimulate myocardial contractility by increasing the intracellular cyclic AMP concentrations. They can also increase Ca2+ entry and inhibit Ca2+ sequestration by the sarcoplasmic reticulum. Xanthines produce bronchodilation with associated venous and arteriolar dilation. However, their use is limited by their positive chronotropic effect and other side effects at high plasma levels. New phosphodiesterase inhibitors have been perfected: they are more specific with little chronotropic effect. Increasing the sensitivity of the myofilaments to Ca2+, and other unclear mechanisms may be involved in the inotropic action of these drugs. These new promising active compounds are described and discussed. They augment cardiac performance and improve regional distribution of blood flow and symptoms. However, their influence on the long-term outcome of severe heart failure has yet to be determined.
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PMID:The new inotropic phosphodiesterase inhibitors. 608 43


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