Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0018799 (heart disease)
 34,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Downregulation of the L-type Ca(2+) current (I(Ca)) is an important determinant of the electrical remodeling of diseased atria. Using a rat model of heart failure (HF) due to ischemic cardiopathy, we studied I(Ca) in isolated left atrial myocytes with the whole-cell patch-clamp technique and biochemical assays. I(Ca) density was markedly reduced (1.7+/-0.1 pA/pF) compared with sham-operated rats (S) (4.1+/-0.2 pA/pF), but its gating properties were unchanged. Calcium channel alpha(1C)-subunit quantities were not significantly different between S and HF. The beta-adrenergic agonist isoproterenol (1 micromol/L) had far greater stimulatory effects on I(Ca) in HF than in S (2.5- versus 1-fold), thereby suppressing the difference in current density. Dialyzing cells with 100 micromol/L cAMP or pretreating them with the phosphatase inhibitor okadaic acid also increased I(Ca) and suppressed the difference in density between S and HF. Intracellular cAMP content was reduced more in HF than in S. The phosphodiesterase inhibitor 3-isobutyl-1-methyl-xanthine had a greater effect on I(Ca) in HF than in S (76.0+/-11.2% versus 15.8+/-21.2%), whereas the inhibitory effect of atrial natriuretic peptide on I(Ca) was more important in S than in HF (54.1+/-4.8% versus 24.3+/-8.8%). Cyclic GMP extruded from HF myocytes was enhanced compared with S (55.8+/-8.0 versus 6.2+/-4.0 pmol. mL(-1)). Thus, I(Ca) downregulation in atrial myocytes from rats with heart failure is caused by changes in basal cAMP-dependent regulation of the current and is associated with increased response to catecholamines.
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PMID:Mechanisms of L-type Ca(2+) current downregulation in rat atrial myocytes during heart failure. 1157 26

Utilizing aortopulmonary vascular graft placement, we established a lamb model of pulmonary hypertension that mimics congenital heart disease with increased pulmonary blood flow. We previously demonstrated that endothelial nitric oxide synthase (eNOS) is increased in lambs at age 4 wk. However, these lambs display a selective impairment of endothelium-dependent pulmonary vasodilation that is suggestive of a derangement downstream of NO release. Thus our objective was to characterize potential alterations in the expression and activity of soluble guanylate cyclase (sGC) and phosphodiesterase type 5 (PDE5) induced by increased pulmonary blood flow and pulmonary hypertension. Late-gestational fetal lambs (n = 10) underwent in utero placement of an aortopulmonary vascular graft (shunt). Western blotting analysis on lung tissue from 4-wk-old shunted lambs and age-matched controls showed that protein for both subunits of sGC was increased in shunted lamb lungs compared with age-matched controls. Similarly, cGMP levels were increased in shunted lamb lungs compared with age-matched controls. However, PDE5 expression and activity were also increased in shunted lambs. Thus although cGMP generation was increased, concomitant upregulation of PDE5 expression and activity may have (at least partially) limited and accounted for the impairment of endothelium-dependent pulmonary vasodilation in shunted lambs.
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PMID:sGC and PDE5 are elevated in lambs with increased pulmonary blood flow and pulmonary hypertension. 1159 95

We used the relation between intracellular Ca(2+) concentration ([Ca(2+)](i)) and cell shortening during tetanus to evaluate the endogenous characteristics of Ca(2+) responsiveness of myofibrils in mouse ventricular myocytes. Enzymatically isolated myocytes were loaded with fura-2 AM (4 microM for 10 min), and the fura-2 fluorescence ratio at 340 and 380 nm excitation wave length [F(340)/F(380)] and cell length were measured simultaneously. Following treatment with thapsigargin (0.2 microM) (an inhibitor of the Ca(2+) pump of sarcoplasmic reticulum), myocytes were stimulated at 10 Hz for 10 s to produce a tetanic contraction and an instantaneous plot of the fluorescence ratio signal versus cell length (R-L trajectory) was constructed. An increase in the extracellular Ca(2+) concentration ([Ca(2+)](o)) from 0.5 to 2 mM extended the R-L trajectory without a substantial shift of the relation. The R-L trajectory was shifted rightward by the nonselective phosphodiesterase inhibitor, 3-isobutyl-1-methyl-xantine (IBMX, 200 microM) (desensitization of the myofibrils to Ca(2+)), and shifted leftward by the Ca(2+) sensitizing thiadiazinone derivative, EMD-57033 (0.5 microM) (sensitization of the myofibrils to Ca(2+)). Beta-adrenergic stimulant, isoproterenol (5 nM), also shifted the R-L trajectory to the right, suggesting that the membrane receptor could be preserved. These results suggest that the R-L trajectory is a useful method to estimate the myofibrillar responsiveness to Ca(2+) in isolated mouse myocytes and can be applied to various mouse models of heart disease.
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PMID:Use of tetanus to investigate myofibrillar responsiveness to Ca(2+) in isolated mouse ventricular myocytes. 1204 10

Since depression of myocardial contractility forms the basis for the development of heart failure, many attempts have been made to enhance the inotropic state of the failing heart by cardiotonic agent as the therapeutic modality. However, large scale clinical trials conducted in the Western societies revealed excess mortality in patients with heart failure received long-term treatment with inotropic agent. Therefore, all of these agents are now regarded as unsuitable for chronic heart failure treatment. In contrast, some inotropic agents with phosphodiesterase inhibitory properties exhibited potential benefits in Japanese patients. In Japan mortality due to heart disease is substantially lower than that found in all other Western countries. Thereby, chronic treatment with inotropic agent may be justified as the optimal care in the context of relief of symptoms and an improved quality of life. The salutary effects of these phosphodiesterase inhibitors appear to be related to anticytokine and immunomodulating effects as well as their cardiotonic action. These findings support the recent new concept that immune responses mediated by cytokines play an important role in the pathogenesis of heart failure.
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PMID:Inotropic agents and immune modulation. 1237 2

In Germany, some 4-6 million men, including 1.2 million diabetics, suffer from erectile dysfunction (ED). Various other diseases including heart disease, hypertension, arteriosclerosis, hyperlipidemia, endocrine disorders, chronic renal insufficiency, prior radical prostatectomy, neurological diseases, trauma and the abuse of alcohol, tobacco, and side effects of medications, are frequently associated with ED. Medical history, clinical examination, routine blood chemistry and sexual hormone levels may help clarify the etiology of ED. Normally, relaxation of the smooth muscles of the corpus cavernosum--mediated by cGMP and cAMP--together with dilatation of penile arteries and occlusion of venous outflow, results in an erection. The oral type V phosphodiesterase inhibitor, Sildenafil, or prostaglandin E1 injection elevates the cGMP and cAMP levels, respectively. Other therapeutic options include mechanical aids, surgery, hormone replacement or sublingual apomorphine. Since 1998, Sildenafil, an effective, simple and safe oral treatment, has been available.
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PMID:[Erectile dysfunction. An important manifestation of autonomic diabetic neuropathy]. 1253 21

Cardiovascular diseases including heart failure represent a common disease in patients referred for anesthesia. In most cases, heart failure is caused by left ventricular dysfunction due to coronary heart disease. The aims of the treatment of chronic heart failure are the relief of symptoms, the improvement of prognosis and the prevention of the progression of heart failure. The first-line treatment involves the underlying heart disease such as myocardial revascularisation procedures in coronary heart disease or the correction of valve diseases. The pharmacological therapy depends on the stage of heart failure and symptoms of the patient. Heart failure therapy includes ACE-inhibitors, betablockers, diuretics und digitalis. Nitrates can be prescribed in patients with symptomatic heart failure despite adequate therapy but calcium antagonists are not recommended. Repeated or prolonged treatment with positive inotropic agents like phosphodiesterase inhibitors or beta-adrenergic drugs increases mortality but this is commonly used in acute stages of heart failure refractory to treatment. Interactions of ACE-inhibitors or AT1- antagonists with anesthetic agents can lead to severe hypotension especially in hypovolemic patients. Whether those drugs should be continued perioperatively or not has been controversially discussed. The use of betablockers has a positive impact on cardiac morbidity and mortality during and early after surgery. Chronic treatment with diuretics can be associated with hypovolemia and an imbalance of electrolytes leading to hypotension and arrhythmia during anesthesia but careful evaluation prior to anesthesia can avoid such complications. The continuation of digitalis during anesthesia has been controversially discussed due to the various interactions with anesthetics.
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PMID:[Current treatment of chronic heart failure]. 1289 47

Pulmonary arterial hypertension (PAH) is a rare condition characterised by elevated pulmonary arterial resistance leading to right heart failure. PAH can be sporadic (idiopathic PAH, or primary pulmonary hypertension), familial (caused by germline BMPR2 mutations, a type II member of the TGFbeta receptor superfamily), or related to other conditions including connective tissue disease, congenital heart disease, human immunodeficiency virus infection, portal hypertension, appetite suppressant exposure... Idiopathic PAH has a prevalence of 2 per million per year in France. The lack of specificity of PAH symptoms (mostly dyspnea) presumably lead to underdiagnosis of this condition. Echocardiography is the investigation of choice for non-invasive screening. Measurement of hemodynamic parameters during right-heart catheterism is mandatory to establish the diagnosis (mean pulmonary artery pressure >25 mmHg and pulmonary artery wedge pressure <12 mmHg). Acute pulmonary vasodilator testing should be performed with nitric oxide or prostacyclin during right-heart catheterization. Recent advances in the management of PAH including continuous intravenous prostacyclin infusion and endothelin receptor antagonists have improved markedly the patients' prognosis. Novel treatments such as inhaled iloprost and type 5 phosphodiesterase inhibitors have to be further evaluated in this setting. Lung transplantation is the last option for patients deteriorating despite medical treatment.
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PMID:[Pulmonary arterial hypertension]. 1504 92

Infants undergoing surgery for congenital heart disease are at risk for myocardial ischemia during cardiopulmonary bypass, circulatory arrest, or low-flow states. The purpose of this study was to demonstrate the effects of sildenafil, a selective phosphodiesterase-5 (PDE-5) inhibitor on myocardial functional improvement and infarct size reduction during ischemia/reperfusion injury in infant rabbits. Infant rabbits (aged 8 wk) were treated with sildenafil citrate (0.7 mg/kg i.v.) or normal saline 30 min before sustained ischemia for 30 min and reperfusion for 3 h. Transesophageal echocardiography (TEE) was used to assess left ventricular cardiac output (LVCO) and aortic velocity time integral (VTI). After ischemia/reperfusion, risk area was demarcated by Evan's blue dye and infarct size determined by computer morphometry of triphenyltetrazolium chloride-stained sections. The sildenafil-treated group had preservation and elevation in LVCO (143% of baseline, p < 0.05) and an elevated aortic VTI (145% of baseline, p < 0.05) after 30 min of ischemia compared with the control group LVCO (72% of baseline, p < 0.05) and aortic VTI (73% of baseline, p < 0.05). This is a statistically significant increase in LVCO and aortic VTI in the sildenafil group compared with controls (n = 6/group, p < 0.05). The sildenafil-treated group had significant reduction in infarct size (15.5 +/- 1.2 versus 33 +/- 2.3 in the saline group, % risk area, mean +/- SEM, n = 10-15/group, p < 0.05). For the first time, we have shown that sildenafil citrate promotes myocardial protection in infant rabbits as evidenced by postischemic preservation and elevation in LVCO and aortic VTI and reduction in infarct size.
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PMID:Sildenafil citrate (viagra) induces cardioprotective effects after ischemia/reperfusion injury in infant rabbits. 1553 35

Phosphodiesterases (PDEs) modulate signaling by cyclic nucleotides in diverse processes such as cardiac contractility, platelet aggregation, lipolysis, glycogenolysis, and smooth muscle contraction. Cyclic guanosine monophosphate (cGMP) stimulated human phosphodiesterase 2 (PDE2) is expressed mainly in brain and heart tissues. PDE2A is involved in the regulation of blood pressure and fluid homeostasis by the atrial natriuretic peptide (ANP), making PDE2-type enzymes important targets for drug discovery. The design of more potent and selective inhibitors of PDE2A for the treatment of heart disease would be greatly aided by the identification of active site residues in PDE2A that determine substrate and inhibitor selectivity. The identification of active site residues through traditional mutational studies involves the time-consuming and tedious purification of a large number of mutant proteins from overexpressing cells. Here we report an alternative approach to rapidly produce active site mutants of human PDE2A and identify their enzymatic properties using a wheat germ in vitro translation (IVT, also known as cell-free translation) system. We also present the crystal structure of the catalytic domain of human PDE2A determined at 1.7 A resolution, which provided a framework for the rational design of active site mutants. Using a rapid IVT approach for expression of human PDE2A mutants, we identified the roles of active site residues Asp811, Gln812, Ile826, and Tyr827 in inhibitor and substrate selectivity for PDE2A.
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PMID:Structural determinants for inhibitor specificity and selectivity in PDE2A using the wheat germ in vitro translation system. 1593 21

Inhaled nitric oxide (iNO) has been shown to be a potent and selective vasodilator in pulmonary arterial hypertension (PAH). However, the clinical experience in prolonged treatment is limited. We assess the safety and effectiveness of long-term administration of iNO in severe PAH. Two female patients were admitted to our hospital because of severe dyspnea (World Health Organization functional class IV) and hypoxemia. They were diagnosed with PAH (primary and secondary to congenital heart disease) and treated with iNO for 2 years. The delivery system consisted of an NO tank of 800 ppm, a modified gas-pulsing device, and nasal cannulas. On iNO treatment the patients showed remarkable improvement of symptoms, oxygenation and 6-min walk distance. After 16 months the patients began to experience a progressive rebound of symptoms. A phosphodiesterase type 5 inhibitor (dipyridamole) was added to iNO. This intervention proved useful in improving clinical deterioration and hemodynamics. This is the first study reporting 2-year iNO therapy in 2 patients with primary and secondary pulmonary hypertension. The combination of dipyridamole with iNO augments the pulmonary vasodilatation and may be useful in managing PAH.
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PMID:Long-term inhaled nitric oxide plus dipyridamole for pulmonary arterial hypertension. 1608 87


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