Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0018681 (headache)
 56,091 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Iloprost is an analogue of epoprostenol (prostacyclin; PGI2; a potent but short-lived prostanoid mainly produced in the vascular endothelium) and mimics the pharmacodynamic properties of this compound, namely: inhibition of platelet aggregation, vasodilatation and, as yet ill-defined, cytoprotection. Improved metabolic and, in particular, chemical stability enhance the clinical utility of iloprost. When administered as an intermittent intravenous infusion at less than or equal to 2 ng/kg/min for 2 to 4 weeks, iloprost reduced rest pain and improved ulcer healing in 40 to 60% of patients with critical leg ischaemia, including diabetic patients, and delayed amputation in the majority of responding individuals. Similar benefits have been seen in thromboangiitis obliterans and, in patients with severe Raynaud's phenomenon, shorter courses of therapy reduced the frequency, intensity and duration of ischaemic episodes for at least 6 weeks. The very few comparative trials reported to date (i.e. vs nifedipine in Raynaud's phenomenon; vs low-dose aspirin in thromboangiitis obliterans) have favoured iloprost, but comparisons with more established agents are needed to assess this drug's value in less severe forms of peripheral ischaemia, such as intermittent claudication. At present, iloprost is administered intravenously and this is a limitation to treatment. The potent, rapidly reversible antiplatelet activity of iloprost suits it for use in extracorporeal circulation and for the intraoperative management of heparin-induced platelet activation. Although results in animal models of ischaemic myocardial injury are encouraging, preliminary clinical experience in patients with myocardial ischaemia or infarction has been disappointing. Most patients tolerate iloprost infusion rates of up to 2 ng/kg/min. Headache and flushing are extremely common and are the suggested end-point of dose titration, as higher doses are associated with a significant incidence of gastrointestinal distress and, ultimately, hypotension. Thus, iloprost provides a pharmacotherapeutic option for patients with severe peripheral vascular disease, a condition for which few alternative drug therapies exist. Its potent but short-lived effects make it well-suited to certain therapeutic niches such as the management of intraoperative platelet activation. Prostanoid analogues have far-reaching therapeutic potential and further experience with iloprost will no doubt help to define its clinical applications.
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PMID:Iloprost. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in peripheral vascular disease, myocardial ischaemia and extracorporeal circulation procedures. 137 60

Neurologic sequelae may occur months to years after cranial irradiation. The site of primary damage is probably the vascular endothelium. Over a 2.8-year period, four children with brain tumors, a mean of 11 years of age at diagnosis (range, 6.5 to 15.5 years), had new onset of severe intermittent unilateral headaches associated with nausea, episodic visual loss, hemiparesis, aphasia, or hemisensory loss. The headaches lasted 2 to 24 hours. All patients had previously received whole-brain (2,400 to 3,600 cGy) and additional local boost (1,800 to 3,100 cGy) cranial irradiation, as well as cisplatin-, lomustine-, and vincristine-containing chemotherapy regimens. Symptoms began 1.2 to 2.8 years after the diagnosis, when all had stable disease and were off treatment. MRI studies were unchanged, and CSF cytology, EEGs, echocardiograms, and magnetic resonance angiograms were normal in all. Cerebral angiograms, performed in three children, were normal but led to severe headaches and neurologic deficits (hemiparesis in one and visual loss in two) that resolved after 24 to 48 hours. Response to antimigraine and antiplatelet medications was variable. We conclude that (1) "complicated migraine-like episodes" may occur in children after cranial irradiation and chemotherapy as a sequela of therapy; (2) these headaches may not be the harbinger of impending strokes, severe intracranial vasculitis, or tumor recurrence; and (3) while cerebral angiography may be useful in differential diagnosis, it may cause transient worsening of symptoms.
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PMID:'Complicated migraine-like episodes' in children following cranial irradiation and chemotherapy. 747 78

Primary Raynaud's phenomenon is common, particularly in younger women, and may be familial. Vasospasm is not confined to the digits and may involve, for example, the tongue and nose, and also visceral organs like the heart, oesophagus or lung and cerebral circulation. Symptoms tend to be milder in primary compared with secondary Raynaud's phenomenon, which is associated with other disorders such as the connective tissue diseases. Indeed, the severity of symptoms often acts as the predictor for the much later onset of the associated systemic disease. Occupational Raynaud's phenomenon is related to the use of vibrating instruments, and a significant proportion of patients may be cured by an early change in job. In those over 60 years of age, Raynaud's phenomenon is commonly a result of atherosclerotic obstructive arterial disease, and screening for and treatment of the risk factors is appropriate. The best-studied mechanisms in Raynaud's phenomenon involve the blood and vascular endothelium. Microcirculatory flow may be impeded by activated platelet clumps, rigid red and white blood cells and damaged endothelium. These platelet clumps, white blood cells and damaged endothelium also release vasoactive/vasoconstrictive compounds which may additionally trigger the clotting cascade and thrombosis. Initial management for mild disease should focus on support and advice regarding avoidance of known precipitating factors, including vasospastic drugs. Cold protection with warming agents, 'Abel' shoes and also electrically heated gloves and socks is effective, but may be too cumbersome and inconvenient for some patients. Simple vasodilators like naftidrofuryl, inositol nicotinate and possibly pentoxifylline (oxpentifylline) are useful in mild disease, with adverse effects like headache and flushing being less problematic. The 'gold standard' of Raynaud's phenomenon treatment is nifedipine, a calcium channel antagonist/blocker. Full dosage, however, can be limited by ankle swelling, headache and flushing, but adverse effects may be reduced by using the 'retard' or long-acting preparations. Adverse effects are also reduced with the newer calcium channel antagonists like diltiazem but at the expense of efficacy. Useful, enhanced benefit is also achieved by combination therapy with vasodilators. Newer treatments include the prostaglandin analogues which are effective but disadvantaged by their parenteral route of administration, and lack of licence in some countries. Oral preparations are, however, being studied and are in the pipeline. Essential fatty acid supplementation is mildly effective, while ketanserin and calcitonin gene-related peptide both look promising. Lumbar sympathectomy retains its important role in the treatment of Raynaud's phenomenon involving the lower limbs. Satisfactory symptomatic relief is now possible for many patients with Raynaud's phenomenon and this should certainly be the aim for all patients seeking medical help.
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PMID:Pharmacotherapy of Raynaud's phenomenon. 911 18

The molecular mechanisms of migraine pain have not yet been clarified. Neurogenic inflammation and a subsequent plasma extravasation in the dura mater have been suggested. However, monoamine and peptide neurotransmitters involved in neurogenic inflammation do not cause significant head pain. Based on our previous studies of headache induced by i.v.infusions of glyceryl trinitrate (exogenous nitric oxide donor) and histamine (which liberates nitric oxide from vascular endothelium), we suggest that nitric oxide (NO) is a more likely candidate molecule. The present review deals with the biology of this small messenger molecule and the scientific evidence suggesting a key role for this molecule in migraine headache. We hypothesise that the release of NO from either blood vessels, perivascular nerve endings, or brain tissue is a molecule trigger mechanism of spontaneous migraine pain. These novel observations dictate new approaches to the pharmacological treatment of migraine.
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PMID:Nitric oxide theory of migraine. 952 55

Glyceryl trinitrate, an exogenous nitric oxide (NO) donor, and histamine, which causes NO formation in vascular endothelium, have been shown to trigger migraine attacks. However, it remains uncertain whether NO is involved in the subsequent phase of migraine attacks. To answer this question we studied the effect of L-NGmethylarginine hydrochloride (546C88), a NO-synthase inhibitor, on spontaneous migraine attacks. In a double-blind study design, 18 patients with migraine without aura randomly received 546C88 (6 mg/kg) or placebo (5% dextrose) i.v. given over 15 min for a single migraine attack (546C88:placebo, 15:3). Furthermore, 11 placebo-treated patients from previous double-blind trials with almost identical design were added to the placebo group in the statistical evaluation. Two hours after the infusion, 10 of 15 L-NGmethylarginine hydrochloride-treated patients experienced headache relief compared to 2 of 14 placebo-treated patients (p = 0.01). Symptoms such as phono- and photophobia were also significantly improved. A similar trend for nausea was not significant. We conclude that NO may be involved in the pain mechanisms throughout the course of spontaneous migraine attacks.
Cephalalgia 1998 Jan
PMID:Nitric oxide synthase inhibition: a new principle in the treatment of migraine attacks. 960 21

The molecular mechanisms of migraine pain have not yet been clarified. Neurogenic inflammation and a subsequent plasma extravasation in the dura mater have been suggested as causative factors. However, monoamine and peptide neurotransmitters involved in neurogenic inflammation do not cause significant head pain. Based on our previous studies of headache induced by i.v. infusions of glyceryl trinitrate (exogenous nitric oxide [NO] donor) and histamine (which liberates NO from the vascular endothelium), it is suggested that NO is a more likely candidate molecule. The present review examines the biology of this small messenger molecule, and the scientific evidence suggesting that it may play a key role in migraine headache. It is hypothesized that the release of NO from blood vessels, perivascular nerve endings or from brain tissue is a molecular mechanism which triggers spontaneous migraine pain. Furthermore, it has been shown that this hypothesis is supported by the recent findings that i.v. infusion of the NO synthase (NOS) inhibitor is effective in the acute treatment of migraine attacks. These novel observations indicate possible new approaches to the pharmacological treatment of migraine.
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PMID:Nitric oxide mechanisms in migraine. 1107 43

The molecular mechanisms that underlie the primary headaches-migraine, cluster headache and tension-type headache-have not yet been clarified. On the basis of studies in headache induced by intravenous infusions of glyceryl trinitrate (an exogenous nitric oxide donor) and histamine (which liberates nitric oxide from vascular endothelium), it has been suggested that nitric oxide is a likely candidate responsible molecule. The present review deals with the biology of this small messenger molecule, and the updated scientific evidence that suggests a key role for this molecule in primary headaches. This evidence suggests that the release of nitric oxide from blood vessels, perivascular nerve endings or from brain tissue is an important molecular trigger mechanism in spontaneous headache pain. Pilot trials have shown efficacy of a nitric oxide synthase inhibitor in both migraine attacks and chronic tension-type headache. These observations suggest new approaches to the pharmacological treatment of headache.
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PMID:Nitric oxide in primary headaches. 1137 54

Reversible posterior leucoencephalopathy syndrome (RPLS) has previously been described in patients who have renal insufficiency, eclampsia, hypertensive encephalopathy and patients receiving immunosuppressive therapy. The mechanism by which immunosuppressive agents can cause this syndrome is not clear, but it is probably related with cytotoxic effects of these agents on the vascular endothelium. We report eight patients who received cyclosporine A (CSA) after allogeneic bone marrow transplantation or as treatment for severe aplastic anemia (SSA) who developed posterior leucoencephalopathy. The most common signs and symptoms were seizures and headache. Neurological dysfunction occurred preceded by or concomitant with high blood pressure and some degree of acute renal failure in six patients. Computerized tomography studies showed low-density white matter lesions involving the posterior areas of cerebral hemispheres. Symptoms and neuroimaging abnormalities were reversible and improvement occurred in all patients when given lower doses of CSA or when the drug was withdrawn. RPLS may be considered an expression of CSA neurotoxicity.
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PMID:Reversible posterior leucoencephalopathy syndrome associated with bone marrow transplantation. 1159 83

Methotrexate-induced neurotoxicity (MTX-Ntox) is a frequent complication of methotrexate (MTX) therapy for patients with both malignant and inflammatory diseases. MTX-Ntox can occur after intrathecal MTX or after low-, intermediate-, or high-dose systemic administration. Symptoms can present in the acute, subacute, or late setting form, and can range from affective disorders, malaise, and headaches, to somnolence, focal neurologic deficits, and seizures. While the pathogenesis of MTX-Ntox is likely multifactorial, one potential biochemical pathway leading from MTX to neurotoxicity involves the folate dependent remethylation of homocysteine (Hcy). MTX therapy is known to cause elevations of both plasma and CSF Hcy. Hcy is directly toxic to vascular endothelium and it and its metabolites are excitatory agonists of the N-methyl-D-aspartate (NMDA) receptor. Competitive or noncompetitive antagonists might afford protection from or reversal of MTX-Ntox. Using high-performance liquid chromatography (HPLC) with coulometric electrochemical detection, the authors measured CSF Hcy in sequential patients with severe subacute MTX-Ntox. CSF Hcy was higher in these patients (n = 9, median = 0.93 microM) than in asymptomatic patients (n = 11, median 0.2 microM, p < .01). Five patients with severe subacute MTX-Ntox (most with dysarthria and/or hemiplegia) were treated with 1-2 mg/kg oral dextromethorphan (DM), a noncompetitive antagonist of the N-methyl-1-aspartate (NMDA) receptor. All five had resolution of symptoms. These data provide additional clinical support for elevated CSF Hcy in the induction of MTX-Ntox through activation of the NMDA-receptor. These data provide support for a placebo-controlled clinical trial to examine the ability of DM to prevent or alleviate MTX-Ntox.
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PMID:Dextromethorphan is effective in the treatment of subacute methotrexate neurotoxicity. 1207 63

The compound m-chlorophenylpiperazine (mCPP), which is known to trigger migraine-like head pain in some subjects, was evaluated for its ability to induce dural plasma protein extravasation (PPE) in guinea pigs. Intravenous mCPP dose-dependently increased PPE. This effect was inhibited by non-selective 5-HT2 receptor antagonists (methysergide, LY53857, LY215840), by a peripherally restricted 5-HT2 receptor antagonist (xylamidine) and by a 5-HT2B selective receptor antagonist (LY202146). These data suggests that peripheral 5-HT2B receptors mediate mCPP-induced PPE. The nitric oxide synthase inhibitor L-NAME and 5-HT1 agonist sumatriptan also blocked mCPP-induced PPE, suggesting a role for nitric oxide (NO) and the trigeminal system, respectively. NO release has been linked to activation of the 5-HT2B receptor on the vascular endothelium. However, LY202146 did not block PPE induced by electrical stimulation of the trigeminal ganglion. These data are consistent with activation of peripheral 5-HT2B receptors initiating PPE and the theory that selective 5-HT2B antagonists might be effective prophylactic therapies for migraine.
Cephalalgia 2003 Mar
PMID:Neurogenic dural protein extravasation induced by meta-chlorophenylpiperazine (mCPP) involves nitric oxide and 5-HT2B receptor activation. 1260 68


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