Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Twelve dogs suffering from acute lymphoblastic leukaemia were investigated concerning the following tests: platelet count, prothrombin time (PT, standard test, modified test), activated partial thromboplastin time (APTT), activity of the individual coagulation factors II, V, VII, X, VIII:C, IX, XI, XII, prekallikrein, and high-molecular weight kininogen, the activity of antithrombin III (AT III), protein C, plasminogen, and alpha 2-antiplasmin as well as concentration of fibrinogen, soluble fibrin and fibrin(ogen) degradation products (FDP). All patients showed a decreased platelet count due to suppression of megakaryopoesis by infiltration of the bone marrow with leukaemic cells. In addition, in most of the patients a moderate activity decrease of one or more individual coagulation factors has been found, especially regarding factor II (median, x0.50 = 51%, p = 0.0001), but also factors X (x0.50 = 71%, p = 0.0003) and XI (x0.50 = 68%, p = 0.0006). This was reflected by the APTT and the PT activity (modified test), which were prolonged or decreased, respectively, in the majority of the cases. Furthermore, the activity of AT III and of plasminogen was distinctly diminished (p < 0.001). Like the concentration of FDP, the plasma level of soluble fibrin was significantly higher than in normal dogs (p < 0.001). This indicates that besides thrombocytopenia disseminated intravascular coagulation occurs frequently in dogs with acute lymphoblastic leukaemia and is a main cause for the decreased activity of several plasmatic components of the haemostatic system. The lack of correlation between the concentration of soluble fibrin as an indicator of intravascular coagulation and the total blast cell count (rS = 0.011) shows the importance of other factors like degree of cell lysis as well as participation of organs such as the liver for generation of consumption coagulopathy in dogs with acute lymphoblastic leukaemia.
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PMID:[Changes in hemostasis of dogs with acute lymphoblastic leukemia]. 951 98

All-trans retinoic acid (RA) has been successfully used in the treatment of patients with acute promyelocytic leukemia (APL). It induces differentiation of APL cells and reduces the bleeding tendency in APL patients. It has been proposed that plasminogen activation could affect the fibrinolytic balance in patients with leukemia. In our earlier study we found that treatment of APL cells with RA results in changes in urokinase (uPA) production. As interferons (IFNs) and dexamethasone can be used together with RA in the treatment of patients with APL, we have now studied the effects of RA together with IFNs and dexamethasone on the plasminogen activation cascade of these cells, including measurement of plasmin generation and uPA receptor (uPAR), using enzyme immunoassays, fluorescence-activated cell sorter analysis and RNA extraction with Northern blotting. Our main results were: (1) plasmin was formed on the surface of APL cells; (2) RA stimulated transiently plasmin generation and increased uPAR mRNA level; (3) IFNs alpha and gamma potentiated RA in its effects on uPA and plasmin activities and on uPAR level; (4) dexamethasone suppressed totally the effect of RA on uPA induction and plasminogen activation; and (5) IFNs and dexamethasone alone did not have potent effects on plasminogen activation. These results may assist in the design of therapy for APL patients.
Leukemia 1998 Feb
PMID:Interferons and retinoids enhance and dexamethasone suppresses urokinase-mediated plasminogen activation in promyelocytic leukemia cells. 951 78

The etiology of thrombo-embolic events after therapy with asparaginase (ASP) is not fully understood. To investigate if cytotoxic drugs given in combination with asparaginase (ASP) have an additional effect on the coagulation system, a detailed analysis of coagulation factors was performed. Therefore, we investigated two combinations of the COALL-05-92-protocol, [cylophosphamide]/methotrexate/ASP ([CYC]/MTX/ASP) and high dose arabinoside/ASP (HIDAC/ASP). In 33 children with acute lymphoblastic leukaemia the following parameters were determined: plasminogen-activator-inhibitor-1, plasminogen, antiplasmin, protein C, antithrombin, modified antithrombin, prothrombin-fragments 1 + 2 and thrombinantithrombin-complex. All children had an indwelling catheter. The most distinctive result of this investigation is that plasminogen shows a deeper and longer lasting decrease in the [CYC]/MTX/ASP-combination (median 65% NHP) compared to the HIDAC/ASP-combination (median 105% NHP) (p = 0.01). The other parameters showed the characteristic changes after ASP-therapy. None of our patients developed any clinical signs of thrombosis, even though two patients showed four altered coagulation parameters on the same day. This shows, that the coexistence of indwelling catheters plus four decreased coagulation parameters does not necessarily imply the development of thrombosis. We conclude that the parameters measured in this study do not sufficiently predict the development of thrombosis.
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PMID:Coagulation and fibrinolysis in children with acute lymphoblastic leukaemia treated according to the COALL-05-92-protocol. 974 67

The active process of pericellular proteolysis is central in tumor invasion, and in particular the essential role of the urokinase-type plasminogen activator (uPA) is well established. uPA-mediated plasminogen activation facilitates cell migration and invasion through extracellular matrices by dissolving connective tissue components. uPA, its receptor (uPAR) and plasminogen activator inhibitor-1 (PAI-1) are enriched in several types of tumors. The importance of proteolysis and especially plasminogen activation is less clear in hematopoietic malignancies than in solid tumors. However, patients with leukemia have an increased tendency to bleeding, not always attributable to thrombocytopenia, and tissue infiltration by leukemic cells, processes in which plasminogen activation may be involved. Several studies have indicated that plasminogen activators (PAs) are highly expressed by cultured leukemia cells. Furthermore, differing from adherent tumor cells, leukemic cells have an enhanced capacity to activate pro-uPA and mainly the active form of uPA is released to culture medium. Ex vivo studies have shown that uPAR, uPA and its inhibitors can be found on the surface of normal blood cells and on the blast cell surfaces from patients with acute leukemia as well as from plasma samples. Elevated levels of PAs and their inhibitors have been detected in leukemic cell lysates. Few studies have tried to demonstrate a correlation between prognosis of leukemia and levels of plasminogen activators. More in vivo studies are needed to show, if any of the factors of the plasminogen activation process can be used as tools in subclassification or as markers for prognosis in leukemia. This review article will focus on the in vivo studies of plasminogen activation in leukemia and will present several in vitro findings on PAs in normal leukocytes and leukemic cell lines.
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PMID:Plasminogen activation in human leukemia and in normal hematopoietic cells. 1019 Feb 91

Plasminogen activation in leukemia has been less well characterized than in other malignancies. However, the increased tendency to bleeding and tissue infiltration by leukemic cells are processes in which plasminogen activation may be involved. We have examined plasma and the peripheral blood mononuclear cell fraction from 80 patients including 53 patients with newly diagnosed acute leukemia and 27 patients with other hematological disorders as well as 21 healthy controls. In 28 of 29 examined patients with acute myeloid leukemia (AML) and in two of three patients with hybrid leukemia we found urokinase receptor (uPAR) on the cell surface, while most (7/9) samples from patients with acute lymphoblastic leukemia (ALL) were negative for uPAR. The plasma mean value for soluble uPAR (suPAR) was significantly elevated in patients with AML and ALL. In AML the highest values were found in patients who had residual disease after several cycles of chemotherapy. Compared to controls the uPA antigen levels in patient plasmas were elevated and decreased along with uPAR during treatment. Our results suggest that cell surface uPAR may be a useful marker for leukemia classification and in our material a high level of plasma suPAR correlated with resistance to chemotherapy in AML.
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PMID:Blast cell-surface and plasma soluble urokinase receptor in acute leukemia patients: relationship to classification and response to therapy. 1036 41

Plasminogen activation is implicated in solid tumour growth, invasion and metatastic spread. However, little is known about its role in leukaemia. We investigated the production by leukaemic cells of plasminogen activators [urokinase (uPA) and tissue-type PA (tPA)], cell surface receptor for uPA (uPAR) and PA inhibitors (PAI-1 and PAI-2). Leukaemic cells from 37 patients [26 with acute myeloid leukaemia (AML) and 11 with acute lymphoid leukaemia (ALL)] were analysed for mRNA content and enzymatic activities. High levels of uPA mRNA were found in M1, M2, M3 and M4-M5 AMLs, whereas tPA mRNA was not detected in any of the analysed cases. uPAR mRNA was confined to subtypes M4-M5. PAI-1 mRNA was detected in M3 and M4-M5. PAI-2 mRNA was found predominantly in M2 and M4-M5. SDS-PAGE/zymography analyses of cell extracts and supernatants after 24 and 48 h of culture confirmed the production of active uPA by AML cells (mainly M4-M5). but not by ALL. The finding of uPA, uPAR, PAI-1 and PAI-2 synthesized by leukaemic cells suggests that plasminogen activation may contribute to the invasive behaviour of these cells, the fibrinolytic imbalance observed in leukaemic patients and the differentiation and proliferation of M4-M5 by interaction of uPA with uPAR.
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PMID:Plasminogen activation in human acute leukaemias. 1055 1

Previously, a specific angiogenesis inhibitor, angiostatin, discovered in urine and serum of tumor-bearing mice, was reported to potently block tumor growth and metastasis in animal models. Detection of angiostatin and its precursor proteins in urine from cancer patients has not been reported. Now, we report the development of an antibody-based analysis system that allows us to detect angiostatin and plasminogen/plasmin (Pgn/plasmin) in the urine of cancer patients. The detection system is a combination of a novel lysine-ELISA assay and Western immunoblot analysis using a specific antibody to human angiostatin and Pgn/plasmin. High levels of Pgn/plasmin were detected in the urine from various cancer patients, whereas healthy individuals showed relatively low levels of urine Pgn/plasmin. Of interest, angiostatin is detectable in urine samples of patients with various cancers, including acute lymphoblastic leukemia, suggesting that angiogenesis may play an important role in the development and progression of leukemia. Our data for the first time show that angiostatin and Pgn/plasmin are present at relatively high levels in the urine of human cancer patients. Detection of urine angiostatin in cancer patients helps us not only to understand the role of this angiogenesis inhibitor in cancer development and progression but also allows us to develop tools of cancer diagnosis and prognosis. Thus angiostatin has both therapeutic and diagnostic implications in cancer disease.
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PMID:Elevated levels of urine angiostatin and plasminogen/plasmin in cancer patients. 1076 60

Purified preparations of circulating leukaemic blast cells from patients with acute myeloid (M1-7) or acute lymphoblastic leukaemia, and the myeloid or lymphoid cells from patients with chronic myeloid or lymphocytic forms of leukaemia, were incorporated into clots prepared from fibrinogen and plasminogen. Patterns of lysis were followed and measured by light transmission in a microtitre plate reader. Mature polymorphonuclear and mononuclear cell fractions from normal individuals were studied concurrently for comparison. Blast cells from the myeloid forms of acute leukaemia (M2-4) and 'myeloid' cell fractions from patients with chronic myeloid leukaemia were capable of lysing plasminogen-containing clots; this activity was neutralized by addition of immunoglobulin against urokinase plasminogen activator (u-PA), but not by anti-tissue plasmogen activator (t-PA). Mature polymorphonuclear and mononuclear cells from normal individuals lacked lytic activity, as did the leukaemic cells from patients with acute lymphoblastic or chronic lymphocytic leukaemia. Lysed blast cells showed the presence of free plasminogen activator on sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) with overlay zymography, also neutralized by anti-u-PA, whereas normal polymorphonuclear and mononuclear cells did not. These observations suggest that mechanisms underlying some forms of severe bleeding in acute myeloid leukaemias have a critical fibrinolytic component generated by the blast cells themselves.
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PMID:Myeloid leukaemic cells can lyse fibrin directly. 1112 94

We measured the plasma level of fibrinogen in 560 patients with disseminated intravascular coagulation (DIC) and evaluated its relationship with outcome and with other hemostatic markers. Forty-seven percent of patients had >200 mg/dL of plasma fibrinogen and 24% had <100 mg/dl of plasma fibrinogen, suggesting that plasma fibrinogen level is not a sensitive marker for DIC. In our analysis of outcome and plasma fibrinogen levels, the rate of death was high in leukemia/lymphoma patients with high fibrinogen concentration, but no significant difference in outcome was observed in relation to plasma fibrinogen concentration in non-leukemia/lymphoma patients with DIC. Among patients with leukemia/lymphoma, the frequency of organ failure was markedly high in patients with high plasma levels of fibrinogen. Among patients without leukemia/lymphoma, the frequency of organ failure increased concomitantly with the increase in plasma fibrinogen levels. The international normalized ratio was significantly increased in leukemia/lymphoma patients with low fibrinogen. FDP levels were slightly increased in patients with low fibrinogen. Platelet count was significantly low in patients without leukemia/lymphoma with high fibrinogen. DIC score increased concomitantly with the reduction in plasma fibrinogen levels. Plasma levels of thrombomodulin and tissue factor were significantly high in patients with high fibrinogen levels. Plasma levels of antiplasmin and plasminogen were significantly decreased in patients with low fibrinogen. Plasma levels of plasmin plasmin-inhibitor complex and tissue type plasminogen activator/plasminogen activator inhibitor-1 complex (PAI-I) were significantly higher in patients with low fibrinogen than in those with high fibrinogen. Plasma levels of PAI-I and IL-6 were significantly higher in patients with high fibrinogen than in those with low fibrinogen. Patients with high fibrinogen levels showed less activation of secondary fibrinolysis, which might explain the occurrence of organ failure and poor outcome.
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PMID:High plasma fibrinogen level is associated with poor clinical outcome in DIC patients. 1250 60

We investigated the involvement of the urokinase-type plasminogen-activator receptor (uPAR) in granulocyte-colony-stimulating factor (G-CSF)-induced mobilization of CD34+ hematopoietic stem cells (HSCs) from 16 healthy donors. Analysis of peripheral blood mononuclear cells (PBMNCs) showed an increased uPAR expression after G-CSF treatment in CD33+ myeloid and CD14+ monocytic cells, whereas mobilized CD34+ HSCs remained uPAR negative. G-CSF treatment also induced an increase in serum levels of soluble uPAR (suPAR). Cleaved forms of suPAR (c-suPAR) were released in vitro by PBMNCs and were also detected in the serum of G-CSF-treated donors. c-suPAR was able to chemoattract CD34+ KG1 leukemia cells and CD34+ HSCs, as documented by their in vitro migratory response to a chemotactic suPAR-derived peptide (uPAR84-95). uPAR84-95 induced CD34+ KG1 and CD34+ HSC migration by activating the high-affinity fMet-Leu-Phe (fMLP) receptor (FPR). In addition, uPAR84-95 inhibited CD34+ KG1 and CD34+ HSC in vitro migration toward the stromal-derived factor 1 (SDF1), thus suggesting the heterologous desensitization of its receptor, CXCR4. Finally, uPAR84-95 treatment significantly increased the output of clonogenic progenitors from long-term cultures of CD34+ HSCs. Our findings demonstrate that G-CSF-induced upregulation of uPAR on circulating CD33+ and CD14+ cells is associated with increased uPAR shedding, which leads to the appearance of serum c-suPAR. c-suPAR could contribute to the mobilization of HSCs by promoting their FPR-mediated migration and by inducing CXCR4 desensitization.
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PMID:Involvement of the urokinase-type plasminogen activator receptor in hematopoietic stem cell mobilization. 1574 4


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