Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023473 (chronic myeloid leukemia)
 18,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The redistribution of platelet membrane glycoprotein IV (GPIV) and the release of intracellular alpha-granule thrombospondin (TSP) were examined and the inhibition of beta-thromboglobulin (beta-TG) and platelet factor 4 (PF4) in patients with chronic myelogenous leukemia (CML) was observed and quantitation of beta-TG and PF4 in sera was conducted. GPIV in inactive platelet from CML was 36080 +/- 17010 molecules/platelet as compared with 13190 +/- 4810 from the controls (P < 0.01). No abnormality was found in the distribution of platelet membrane GPIb and GPIIb/IIIa (P > 0.05). The GPIV redistribution on active platelet membrane induced thrombin (IU/ml) from CML and healthy donors was 44320 +/- 32310 and 22800 +/- 12700 molecules/platelet respectively (P < 0.01). The difference in the release of intracellular alpha-granule TSP between CML and the control group was not found (P > 0.05). There was no direct correlation between GPIV expression and TSP binding after platelet activation. The high levels of beta-TG and PF4 in sera inhibited release of intracellular alpha-granule TSP in vitro. These results indicate that the abnormality of platelet membrane GPIV is a common marker in CML, therefore the specific increase of platelet GPIV in patients with CML may be a useful tool for the diagnosis and monitoring of the platelet dysfunction. The release of internal TSP pools is hindered by either beta-TG or PF4 in sera.
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PMID:Redistribution of platelet membrane glycoprotein IV and release of intracellular alpha-granule thrombospondin in patients with chronic myelogenous leukemia. 963 79

The pathogenesis of polycythemia vera (PV), a disease involving a multipotent hematopoietic progenitor cell, is unknown. Thrombopoietin (TPO) is a newly characterized hematopoietic growth factor which regulates the production of multipotent hematopoietic progenitor cells as well as platelets. To evaluate the possibility that an abnormality in TPO-mediated signal transduction might be involved in the pathogenesis of PV, we examined TPO-induced protein tyrosine phosphorylation using platelets as a surrogate model system. Platelets were isolated from the blood of patients with PV as well as from patients with other chronic myeloproliferative disorders and control subjects. Impaired TPO-mediated platelet protein tyrosine phosphorylation was a consistent observation in patients with PV as well as those with idiopathic myelofibrosis (IMF), in contrast to patients with essential thrombocytosis, chronic myelogenous leukemia, secondary erythrocytosis, iron deficiency anemia, hemochromatosis, or normal volunteers. Thrombin-mediated platelet protein tyrosine phosphorylation was intact in PV platelets as was expression of the appropriate tyrosine kinases and their cognate substrates. However, expression of the platelet TPO receptor, Mpl, as determined by immunoblotting, chemical crosslinking or flow cytometry was markedly reduced or absent in 34 of 34 PV patients and also in 13 of 14 IMF patients. Impaired TPO-induced protein tyrosine phosphorylation in PV and IMF platelets was uniformly associated with markedly reduced or absent expression of Mpl. We conclude that reduced expression of Mpl is a phenotypic characteristic of platelets from patients with PV and IMF. The abnormality appears to distinguish PV from other forms of erythrocytosis and may be involved in the platelet function defect associated with PV.
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PMID:A novel thrombopoietin signaling defect in polycythemia vera platelets. 1101 90

Oligonucleotides (ON) have been used in vitro, in vivo and clinically for the treatment viral infections, malignancies and inflammatory diseases. This review will focus on the application of ON-based therapeutics for hematological disease. The primary application of ONs has been as sequence specific inhibitors of gene expression, ie, antisense oligonucleotides (AS ON) and ribozymes. Based upon the unique expression of the Bcl-Abl neogene in CML cells, numerous studies have targeted this product with AS ONs and ribozymes. These studies demonstrate that ON targeting the breakpoint region selectively inhibit the proliferation of CML cells. Subsequent studies suggest that this effect may not be due to a true antisense effect of the ON. Other targets, which are being exploited for the treatment of hematological malignancies, include ON targeting c-myb gene, p53 and Bcl-2. All three have entered clinical trials and have been shown to be tolerated by patients. In addition to inhibition of gene expression, ON can be selected for sequence specific binding to proteins (aptamer). In particular an ON that binds to thrombin with high affinity is being explored as a potential anticoagulant. These early studies have identified limitations for first generation ON which may be solvable with newer ON chemistries and/or formulations. Although the technology is still nascent it continues to show promise.
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PMID:Oligonucleotide therapeutics: clothing the emperor. 1171 94

A hypercoagulable state is frequently described in adult patients undergoing bone marrow transplantation (BMT). In this study, the coagulation profile of 29 children was prospectively investigated in the pre- and post-transplant period. A significant rise in the activated partial thromboplastin time (aPTT) values was detected on days 7 and 14 after transplantation. Moreover, an increase in the d-dimer level was also notable, regardless of the clinical condition of the patients. The other coagulation parameters investigated (i.e. protein S, protein C, anti-thrombin III, factor VIII, von Willebrand factor, and prothrombin time) remained essentially unchanged. However, hyper-fibrinogenemia was observed in all patients with chronic myeloid leukemia (CML) (n=5) before and after transplantation. In summary, in the present study pediatric bone marrow transplantation patients did not show a hyper-coagulable state after marrow infusion. However, a significant rise in PTT and d-dimer values were noted.
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PMID:Evaluation of coagulation in pediatric bone marrow transplantation patients. 1173 68

The current therapeutic strategy for disseminated intravascular coagulation (DIC) is limited to control of the underlying disease, and methods for the effective management of DIC have not been established. We report the successful use of tranexamic acid (TA) combined with unfractionated heparin in a patient with life-threatening bleeding from the sigmoid colon caused by DIC. A 35-year-old man who had undergone allogeneic bone marrow transplantation for chronic myelogenous leukemia was referred for relapse of his leukemia. The patient was first treated with imatinib at 600 mg/day. Although the disappearance of leukemic cells and a decrease in the BCR/ABL fusion gene were observed, he developed massive bleeding from the sigmoid colon after defecation. A laboratory diagnosis of DIC with prominent fibrinolysis was based on elevated levels of both plasmin-alpha2-plasmin inhibitor complex and thrombin-antithrombin III complex. Despite vigorous supportive therapy, including multiple transfusions and aggressive fluid resuscitation, the patient developed hypovolemic shock due to the uncontrollable bleeding. TA combined with unfractionated heparin was instituted to inhibit excessive fibrinolysis. A prompt response was observed soon after the commencement of therapy. No organ dysfunction was observed throughout TA and heparin use. To our knowledge, this report is the first to describe successful treatment with TA combined with heparin for life-threatening intestinal bleeding due to acute DIC associated with hematologic malignancy.
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PMID:Successful combined use of tranexamic acid and unfractionated heparin for life-threatening bleeding associated with intravascular coagulation in a patient with chronic myelogenous leukemia in blast crisis. 1819 7

Dasatinib is an oral potent adenosine triphosphate (ATP)-competitive inhibitor of BCR-ABL, cKIT, platelet-derived growth factor receptor, and SRC family kinases (SFKs), which has demonstrated high efficiency in patients with imatinib-resistant chronic myelogenous leukemia. Here, we show that dasatinib weakly affects platelet activation by thrombin or adenosine diphosphate but is a potent inhibitor of platelet signaling and functions initiated by collagen or FcgammaRIIA cross-linking, which require immunoreceptor tyrosine-based activation motif phosphorylation by SFKs. Accordingly, dasatinib treatment rapidly decreases the volume of thrombi formed under arterial flow conditions in whole blood from patients or mice perfused over a matrix of collagen. Moreover, treatment of mice with dasatinib increases the tail bleeding time in a dose-dependent manner. Interestingly, these effects are rapidly reversible after interruption of the treatment. Our data clearly demonstrate that, in contrast to imatinib, dasatinib affects platelet functions in vitro and in vivo, which has important implications in clinic and could explain increased risks of bleeding observed in patients. Moreover, dasatinib efficiently prevents platelet activation mediated by FcgammaRIIA cross-linking and by sera from patients with heparin-induced thrombocytopenia, suggesting that reversible antiplatelet agents acting as ATP-competitive inhibitors of SFKs may be of therapeutic interest in the treatment of this pathology.
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PMID:The new tyrosine-kinase inhibitor and anticancer drug dasatinib reversibly affects platelet activation in vitro and in vivo. 1971 76

The drugs used to treat hematologic disorders constitute an extraordinary array of agents and include therapy for anemias, bleeding diatheses, thromboembolism and hematologic malignancies. Within many of these categories, hematologic therapies represent molecular understanding of the disease pathophysiology and a treatment targeted precisely at the known aberration. In this chapter we discuss these treatments, with greater emphasis on the most commonly used agents and the latest advances in the specific field. The chapter includes discussion on old (cyclooxygenase inhibitors) and new antiplatelet agents (ADP receptor P2Y12 inhibitors), newly described oral thrombin inhibitors such as dabigatran, treatment targeted at the bcr-abl tyrosine kinase in chronic myeloid leukemia and demethylating agents in myelodysplasia. The discussion is also oriented towards neurologic implications, both therapeutic and toxic, for each therapy or therapeutic group.
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PMID:Commonly used drugs in hematologic disorders. 2436 76

Hemostatic disorders are a major clinical problem in patients with myeloproliferative neoplasms (MPNs) and they are the second most common cause of death in MPN patients, after infections. The aim of this study was to assess the fibrinolytic potential of the blood of patients with MPNs. The study involved 112 patients with MPNs diagnosed at the Hematology Clinic Dr J. Biziel University Hospital No. 2 in Bydgoszcz, Poland. The study group included 63 patients with essential thrombocythemia, 29 with polycythemia vera, 11 with chronic myelogenous leukemia (CML) and nine with primary myelofibrosis. The control group consisted of 25 healthy volunteers who were age and sex-matched. The following parameters were determined: concentration of tissue plasminogen activator antigen (t-PA:Ag), plasminogen activator inhibitor type 1 antigen concentration (PAI-1:Ag), D-dimer, thrombin-antithrombin complexes, fibrinogen, activated partial thromboplastin time and international normalized ratio. The study showed significantly increased t-PA:Ag, PAI-1:Ag and D-dimer levels in patients with MPNs. Moreover, we found increased concentrations of thrombin-antithrombin complexes and fibrinogen, as well as elevated platelet counts. Detailed analysis revealed that t-PA:Ag concentration was elevated in patients with essential thrombocythemia, CML and polycythemia vera. Concentration of PAI-1:Ag was increased in patients with essential thrombocythemia and polycythemia vera; D-dimer was significantly higher in essential thrombocythemia, polycythemia vera, CML and primary myelofibrosis patients. Increased concentrations of t-PA:Ag and D-dimer indicate secondary activation of the fibrinolytic system in patients with MPNs. Elevated levels of PAI-1 in MPN patients may result from its increased production by elevated number of activated platelets and vascular endothelial damage. PAI-1 by having an inhibitory effect on fibrinolysis manifests its procoagulant activity.
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PMID:Selected parameters of hemostasis in patients with myeloproliferative neoplasms. 2450 38

Tyrosine kinase inhibitors (TKI) such as imatinib, nilotinib and dasatinib are now established as highly effective frontline therapies for chronic myeloid leukaemia (CML). Disease control is achieved in the majority of patients and survival is excellent such that recent focus has been on toxicities of these agents. Cumulative data have reported an excess of serious vascular complications, including arterial thrombosis and peripheral arterial occlusive disease, in patients receiving nilotinib in comparison with other TKIs, with resultant interest in delineating the pathophysiology and implications for rationale cardiovascular risk modification. To address this issue, we studied the effects of imatinib, nilotinib and dasatinib on platelet function and thrombus formation in human and mouse models using in vitro, ex vivo and in vivo approaches. In vitro studies demonstrated that dasatinib and imatinib but not nilotinib inhibited ADP, CRP, and collagen-induced platelet aggregation and moreover, that nilotinib potentiated PAR-1-mediated alpha granule release. Pretreatment of wild-type C57BL/6 mice with nilotinib but not imatinib or dasatinib, significantly increased thrombus growth and stability, on type I collagen under ex vivo arterial flow conditions and increased thrombus growth and stability following FeCl3-induced vascular injury of mesenteric arterioles and carotid artery injury in vivo. Whole blood from nilotinib-treated CML patients, demonstrated increased platelet adhesion ex vivo under flow, increased plasma soluble P- and E-selectin, sICAM-1, sVCAM-1, TNF-alpha, IL-6 levels and endogenous thrombin potential (ETP) levels in vivo, despite being on daily low-dose aspirin. These results demonstrate that nilotinib can potentiate platelet and endothelial activation and platelet thrombus formation ex vivo and in vivo.
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PMID:The tyrosine kinase inhibitor, nilotinib potentiates a prothrombotic state. 2749 73

Since the introduction of tyrosine kinase inhibitors, the overall survival of patients with chronic myeloid leukemia has markedly improved. However long term use of these drugs results in various adverse events. Treatment with second generation dasatinib is often complicated by hemorrhagic events. Previous lumi-aggregometry studies have shown impaired platelet function in patients on dasatinib therapy. Dual agonist activated platelets (coated-platelets) are also sensitive indicators of platelet function. We hypothesized that dual activation with convulxin and thrombin of platelets in a flow cytometric assay could be a more sensitive method for detecting platelet dysfunction as compared to single agonist studies used in lumi-aggregometer. Platelets of healthy volunteers incubated with dasatinib as well as platelets from patients on dasatinib therapy were investigated. Low therapeutic plasma level dasatinib concentrations at which a considerable reduction in coated-platelet generation was observed in vitro, did not cause detectable change in platelet aggregation response. Coated-platelet assay and lumi-aggregometry were also investigated at 0, 1 and 4 hours after drug administration in dasatinib treated CML patients. Significant decrease was observed at 1 hour in maximal aggregation by collagen. Although the aggregation curves became normalized by 4 hours, coated-platelet generation was still inhibited in dasatinib treated patients. Nilotinib, another second generation tyrosine kinase inhibitor, had no effect on aggregation and on coated-platelet formation neither in vitro nor in ex vivo samples. At therapeutic plasma levels coated-platelet assay is more sensitive than lumi-aggregometry studies for the demonstration of the inhibitory effect of dasatinib on platelet function.
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PMID:Dasatinib inhibits coated-platelet generation in patients with chronic myeloid leukemia. 3006 28


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