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)

In thirty patients with common migraine the platelet concentrations of met-enkephalin immunoreactivity (ME) (76 +/- 9 pg/mg protein) were similar to those in 23 healthy volunteers (77 +/- 5), suggesting that there is no alteration in the ME pool in this biochemical compartment in migraine. Chronic treatment (4 weeks) with drugs that interfere with 5-hydroxytryptamine (5-HT) synthesis or uptake induced the expected changes in platelet 5-HT levels, i.e. a rise following administration of the 5-HT precursor 5-hydroxytryptophan (daily dose: 300-500 mg, n = 9) and a decrease after amine uptake inhibition by amitryptyline (30-75 mg, n = 7) and even more by chlorimipramine (30-50 mg, n = 9). Platelet ME concentrations rose by up to approximately 90% over the basal values after either 5-hydroxytryptophan (significantly from week 2) or amitriptyline (at week 2) and were unchanged after chlorimipramine, indicating that 5-HT and ME concentrations in platelets can vary independently. The high platelet ME levels following 5-hydroxytryptophan and amitriptyline cannot be explained at present. They might be due either to increased ME synthesis, possibly in the megakaryocyte, or to decreased utilization by platelets or both.
Cephalalgia 1984 Jun
PMID:Platelet met-enkephalin immunoreactivity and 5-hydroxytryptamine concentrations in migraine patients: effects of 5-hydroxytryptophan, amitriptyline and chlorimipramine treatment. 661 Apr 76

Essential thrombocythemia is a clonal myeloproliferative disorder, characterized predominantly by a markedly elevated platelet count without known cause. We report a case that was recognized during investigation of a transient ischemic attack, and review the neurologic findings in 33 patients with unequivocal essential thrombocythemia under prospective study by the Polycythemia Vera Study Group. Twenty-one patients had neurologic manifestations at some point during their course, including headache (13 patients), paresthesiae (10), posterior cerebral circulatory ischemia (9), anterior cerebral circulatory ischemia (6), visual disturbances (6) and epileptic seizures (2). All patients with neurologic symptoms responded satisfactorily to treatment, although continuous or repeated treatment was often required. Therapeutic recommendations include plateletpheresis for major thrombo-hemorrhagic phenomena, or megakaryocyte suppression with radioactive phosphorus, alkylating agents (such as melphalan), or hydroxyurea; minor symptoms may respond to platelet antiaggregating agents.
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PMID:Neurologic manifestations of essential thrombocythemia. 668 92

Anagrelide is an oral imidazoquinazoline agent with an anti-cyclic AMP phosphodiesterase activity and inhibits platelet aggregation in both humans and animals. In addition, it has in humans a species-specific platelet-lowering activity observed at dose levels lower than those required to inhibit platelet aggregation. Because of this, the drug has been tested in patients with clonal thrombocytosis and has been shown to have potent platelet-reducing activity in essential thrombocythemia (ET) and related disorders. The mechanism of action may involve the drug's interference with megakaryocyte maturation. More than 90% of patients with ET respond to anagrelide regardless of the presence or absence of previous therapy. The responses are durable with a median maintenance dose of approximately 2 to 2.5 mg/day. Side effects are related mostly to the drug's direct vasodilating and positive inotropic effects and include headache, fluid retention, tachycardia, and arryhthmias. The place of anagrelide therapy in the current management of patients with ET is discussed.
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PMID:Anagrelide as a new platelet-lowering agent in essential thrombocythemia: mechanism of actin, efficacy, toxicity, current indications. 926 55

The pharmacology, pharmacokinetics, clinical efficacy, adverse effects, and dosage and administration of anagrelide are reviewed. Anagrelide is a selective thrombocytopenic agent with FDA-approved labeling for the treatment of essential thrombocythemia. Clinical trials have shown that the drug may have a role in the treatment of other chronic myeloproliferative disorders, including polycythemia vera, chronic myeloid leukemia, and agnogenic myeloid metaplasia. The mechanism by which anagrelide reduces platelet count is not yet clear. The current hypothesis is that anagrelide affects the late (postmitotic) phases of megakaryocyte development. Anagrelide has a large volume of distribution and is extensively metabolized; less than 1% is recovered unchanged in the urine. Plasma half-life after a 0.5-mg dose is 1.3 hours. Anagrelide's efficacy and safety have been evaluated in open-label, noncomparative trials, in which the response rate was 60-93%. Adverse effects include headache, diarrhea, edema, palpitations, and abdominal pain. Patients with renal or hepatic dysfunction need to be closely monitored for signs of toxicity. The recommended starting dosage is 0.5 mg four times a day or 1 mg twice a day, with dosage adjustment to the lowest effective amount required to reduce and maintain platelet count below 600 x 10(9)/L. The wholesale acquisition price for 0.5-mg capsules is $350 per 100. Whether anagrelide will replace hydroxyurea as first-line therapy in some or all patients remains to be determined. Anagrelide is effective in the treatment of essential thrombocythemia and may have a role in the treatment of other myeloproliferative disorders.
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PMID:Anagrelide, a selective thrombocytopenic agent. 978 84

An 88 year-old woman was admitted complaining of headache. CT scan of the head revealed a right subdural hematoma. She had been followed by a local physician because of chronic thrombocytopenia. Her peripheral platelet count on admission was 0.5 x 10(4)/microliter, with a high serum level of PAIgG. Bone marrow examination revealed marked increase of megakaryocyte. Idiopathic thrombocytopenic purpura(ITP) accompanied with chronic subdural hematoma was diagnosed. Transient increase of platelet count and improvement of subdural hematoma was obtained by administration of prednisolone. However, platelet count decreased with tapering of prednisolone. Then combined administration of a Chinese herbal medicine, EK-49, and ascorbic acid was started. Platelet count gradually increased and no adverse effects were experienced. These results indicated that elderly patients with chronic subdural hematoma can be treated non-invasively, and that a combination of EK-49 and ascorbic acid may be effective in the treatment of refractory ITP.
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PMID:[Successful treatment of an elderly patient with idiopathic thrombocytopenic purpura accompanied with chronic subdural hematoma, using a Chinese herbal medicine, EK-49, and ascorbic acid]. 1130 38

Polycythemia vera (PV) and essential thrombocythemia (ET) are chronic disorders for which there are no medical cures. Clinical sequelae of PV and ET fall into three categories: primary, such as thrombosis and hemorrhage; secondary, resulting from disease progression or treatment. The decision whether to treat the patient is based on the sequelae of no treatment versus short- and long-term toxicities of the three classes of drugs available for treatment: hydroxyurea, interferon-alpha, and anagrelide. Thrombosis is the most common short-term sequelae of untreated disease; the risk increases with age and after the first thrombotic complication. Hydroxyurea, a nonalkylating myelosuppressive agent, is mutagenic and probably leukemogenic over 5 to 15 years, which makes it unsuitable for treating most younger patients. Interferon-alpha, a cytokine that is myelosuppressive and immunomodulatory, has been shown to have a therapeutic effect in both PV and ET. Tolerance to the initial flu-like symptoms of interferon-alpha is usually developed, but dose-limiting symptoms of anorexia, asthenia, and neuropsychiatric disease can occur, along with exacerbation or development of autoimmune diseases. Anagrelide, a quinazoline that inhibits cyclic nucleotide phosphodiesterase, inhibits platelet aggregation and has an idiosyncratic effect of inhibiting megakaryocyte maturation and platelet budding at doses below those that affect platelet function. This agent is a vasodilator with positive inotropic activity and a side-effect profile that may include palpitations, forceful heartbeat, tachycardia, and headache. One in four patients develop fluid retention and/or edema that are controllable with diuretic therapy. Dizziness is frequent, but mild. Because these side effects usually abate in 2 to 4 weeks, successful management of patients taking anagrelide depends on encouraging them to maintain therapy. The availability of these three classes of drugs with differing modes of action suggests that combination therapy may offer the opportunity to achieve better control of proliferation while reducing short-term side effects as well as the risks of dose-related cumulative sequelae.
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PMID:Other secondary sequelae of treatments for myeloproliferative disorders. 1209 54

Essential thrombocythemia (ET) is a chronic myeloproliferative syndrome characterized by thrombocythemia and increased megakaryocytes in bone marrow, thrombosis and/or hemorrhagic manifestations. We report here a ten-year experience in the treatment of ET with anagrelide (A), a non mutagenic drug that inhibits megakaryocyte maturation. Between April 1991 and June 2001, 54 ET patients were included with platelet counts > 900 x 10(9)/l in asymptomatic cases and > 600 x 10(9)/l in symptomatic ones. Age at diagnosis was 39 years (11-83). Previously 30 patients had received treatment with hydroxyurea, alpha INF, busulfan and/or 32P. At diagnosis 18 patients had microvascular obstruction, 7 thrombosis, 8 hemorrhagic manifestations and 3 both hemorrhage and thrombosis. Platelet counts at diagnosis were 1200 x 10(9)/l (600-3472) and before A 995 x 10(9)/l (520-2206). The follow-up from diagnosis was 68 months (9-172) and with A treatment 34 months (2-100). The A dose during the first week of treatment was 2.5 mg/d (1-3) and at maintenance 1.5 mg/d (1-3). Complete response was obtained in 96.3% cases, 77% with platelet counts < 400 x 10(9)/l, and 18.5% < 600 x 10(9)/l. The median time to obtain a complete response was 14 days. Transient adverse effects were present in 66% of patients (headache, nausea, abdominal distention, palpitation and edema). Mild to moderate anemia developed within 2-8 months in 40% of patients. During treatment 8 patients had microvascular obstruction with platelet counts over 400 x 10(9)/l and 7 with normal values. One patient developed myelofibrosis. Five patients died for reasons unrelated to ET. In conclusion, anagrelide was effective in reducing platelet counts and preventing mayor thrombotic events.
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PMID:[Treatment of essential thrombocythemia with anagrelide: a ten-year experience]. 1215 5

Stromal cell-derived factor-1 (SDF-1/CXCL12) plays a key regulatory role in the trafficking of hematopoietic cells. AMD3100 is a specific antagonist of the binding of SDF-1 to its receptor, CXCR4. This phase I study assessed the hematological effects, pharmacokinetics, and safety of administration of AMD3100 to 32 healthy volunteers, including its ability to mobilize CD34+ hematopoietic progenitor cells. A generalized leukocytosis occurred after a single subcutaneous injection of AMD3100 (80 microg/kg) resulting in a maximum white blood cell count of 19.49 +/- 1.27 x 103/microL (mean +/- SEM) at 6 hours. No changes were observed in erythrocyte or platelet counts. Circulating CD34+ cells increased 5-fold after administration of AMD3100 at 80 mug/kg and 15.5-fold in response to AMD3100 at 240 mug/kg, both at 9 hours after injection. Myeloid progenitor cells-colony forming unit granulocytemacrophage (CFU-GM); CFU-granulocyte, eosinophil, monocyte, megakaryocyte (CFU-GEMM); and burst forming units-erythroid showed similar increases in mobilization to the blood with increasing doses of AMD3100. The mobilized cells were in a slow or noncycling state as determined by in vitro high specific activity of 3H-thymidine. Pharmacokinetic studies showed a near linear increase in peak drug levels with increasing doses and nearly complete elimination of the drug by 24 hours. AMD3100 was well tolerated with only mild and transient toxicities (injection site erythema, headache, paresthesia, nausea, and abdominal distension) observed. These observations suggest that AMD3100 may be a clinically useful agent for hematopoietic progenitor cell mobilization.
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PMID:Leukocytosis and Mobilization of CD34+ Hematopoietic Progenitor Cells by AMD3100, a CXCR4 Antagonist. 1862 38