Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.4.1 (phosphodiesterase)
 18,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Theophylline and its derivatives, such as aminophylline, have an established role as bronchodilators, although their mode of action in man is not clear. There is circumstantial evidence that therapeutic doses of theophylline may have a phosphodiesterase inhibiting effect, thus potentiating the effects of cyclic AMP. However, it remains to be established whether this is the primary mode of action of theophylline at the biochemical level. The pathways of theophylline metabolism have been clarified, although most of the enzymes involved have not been characterized. Hepatic microsomal enzyme induction by polycyclic hydrocarbons will increase the rate of theophylline elimination. There are a number of factors which influence theophylline clearance in adults, which is known to be highly variable. These factors include obesity, smoking habit, diet and the presence of such diseases as hepatic cirrhosis, acute pulmonary oedema, cor pulmonale and viral respiratory infection. There is a good correlation between plasma theophylline level and bronchodilator effect. This can be demonstrated at plasma levels as low as 5 microgram/ml, although optimal levels are usually greater than 10 microgram/ml. Unacceptable toxicity usually occurs in association with plasma levels greater than 20 microgram/ml. The maintenance of adequate plasma theophylline levels by the use of a sustained-release aminophylline tablet is discussed.
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PMID:Theophylline: biochemical pharmacology and pharmacokinetics. 22 Jan 19

If the failing left ventricle could be given an effective push, other approaches to the treatment of heart failure would not be needed. We have inotropes only for short-term parenteral use. We have no safe inotrope for chronic oral use. The effect of digitalis is only feeble and the phosphodiesterase inhibitors seem to increase mortality from sudden death. Diuretics are dramatic for acute pulmonary oedema and the mainstay for chronic fluid retention but do not improve the pump and by reducing blood volume stimulate the renin angiotensin system to vasoconstriction, further fluid retention and hypokalaemia. Nitrates drop pre-load without reducing blood volume but tolerance is a problem and stroke volume does not increase. Reduction of afterload helps the failing ventricle to empty, the pull and output increases. The angiotensin converting enzyme inhibitors (ACEI) are now the cornerstone of heart failure treatment, reducing mortality in severe heart failure (CONSENSUS) and superior to standard vasodilator therapy (V-HeFT-2) at improving the survival of patients with mild to moderate heart failure. ACEI can reduce the incidence of ventricular ectopy and probably do this through improving left ventricular function, from decreasing sympathetic tone, reducing myocardial oxygen demand or increasing serum potassium but ACEI did not diminish the incidence of sudden death in the SOLVD trial despite reducing mortality. Disappointingly little improvement in exercise tolerance and persistence of chronic fatigue in heart failure concentrated attention on the periphery.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The push, the pull and the periphery. 144 45

Pulmonary veno-occlusive disease (PVOD) is an uncommon form of pulmonary arterial hypertension characterised by a progressive obstruction of small pulmonary veins that leads to elevation in pulmonary vascular resistance and right ventricular failure. Despite improved understanding and more efficacious treatment options for PAH overall, the prognosis of PVOD remains dismal. Without therapeutic intervention few patients would be expected to survive more than two years. PVOD may occur in both idiopathic and heritable forms, or develop in association with connective tissue disease, chronic respiratory disease, malignancy or bone marrow transplantation, among other causes. A widespread fibrous intimal proliferation that predominantly involves the pulmonary venules and small veins is the key histopathological hallmark. Surgical lung biopsy is considered the definitive diagnostic test but is associated with significant risk and is not recommended. Distinguishing PVOD from PAH on clinical grounds alone is generally not possible, although PVOD is characterised by a higher male/female ratio and higher tobacco exposure. Instead, non-invasive tests may be helpful and the diagnosis is usually based on an integrated assessment that incorporates high resolution computed tomography (septal lines, ground-glass opacities and lymph node enlargement), pulmonary function testing (lower DLCO), arterial blood gas analysis (lower PaO(2) at rest) and bronchoalveolar lavage (occult alveolar haemorrhage). Treatment of PVOD remains challenging as exposure to pulmonary vasodilators and PAH-specific agents may precipitate acute pulmonary oedema. Nonetheless, a number of successful outcomes describing cautious use of prostanoids, endothelin antagonists and phosphodiesterase type-5 inhibitors have been described. Unfortunately, the long term effects of these agents are variable and lung transplantation remains the treatment of choice.
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PMID:Pulmonary veno-occlusive disease: recent progress and current challenges. 2045 32

Sildenafil is one of the most commonly used drugs for the treatment of erectile dysfunction. To date, we found five reported cases of intracerebral bleeding and two reported cases of subarachnoid hemorrhage related to sildenafil use. We report a 49-year-old hypertensive and diabetic patient who presented with acute pulmonary edema and loss of consciousness following ingestion of 100 mg of sildenafil prior to sexual intercourse. He was not previously aware of the presence of an aneurysm and had no family history of it. Computed tomography of his head revealed a subarachnoid hemorrhage due to rupture of a saccular aneurysm with subsequent repeat hemorrhage within a few hours of presentation. A sudden increase in blood pressure led to pulmonary edema. Studies have shown that sildenafil acts on phosphodiesterase-1, -2 and -5 receptors and leads to a secondary increase in intracerebral circulation and vasodilatory effects, leading to sympathetic overactivity which increases the risk for intracranial bleeding.
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PMID:Intracranial aneurysm and sildenafil. 2703 61