Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.1.1 (asparaginase)
 2,695 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of L-asparaginase (L-asp) therapy on circulating antithrombin-III (AT-III) was monitored in three patients with acute lymphoblastic leukemia. Serial determination for AT-III by both a functional assay and an immunologic assay demonstrated a rapid decrease in serum AT-III levels, followed by a protracted recovery beyond the period of L-asp exposure. One of the three patients developed a reversible venous thrombosis of the arm. The mechanism of the L-asparaginase effect may be related to peripheral degradation of AT-III or to inhibition of production.
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PMID:L-asparaginase effect on antithrombin-III levels. 29 86

Saccharomyces cerevisiae X2180-1A synthesizes two forms of asparaginase: L-asparaginase I, an internal constitutive enzyme, and asparaginase II, an external enzyme which is secreted in response to nitrogen starvation. The two enzymes are biochemically and genetically distinct. The structural gene for asparaginase I (asp 1) is closely linked to the trp 4 gene on chromosome IV. The gene controlling the synthesis of asparaginase II is not linked to either the trp 4 or asp 1 genes. The rate of biosynthesis of asparaginase II is unaltered in yeast strains carrying the structural gene mutation for asparaginase I. Asparaginase II has been purified approximately 300-fold from crude extracts of Saccharomyces by heat and pH treatment, ethanol fractionation, ammonium sulfate fractionation followed by Sephadex G-25 chromatography, and DEAE-cellulose chromatography. Multiple activity peaks were obtained which, upon gas chromatographic analysis, exhibit varying mannose to protein ratios. Asparaginase I has been purified approximately 100-fold from crude extracts of Saccharomyces by protamine sulfate treatment, ammonium sulfate fractionation, gel permeation chromatography, and DEAE-cellulose chromatography. No carbohydrate component was observed upon gas chromatographic analysis. Comparative kinetic and analytic studies show the two enzymes have little in common except their ability to hydrolyze L-asparagine to L-aspartic acid and ammonia.
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PMID:Characterization of two forms of asparaginase in Saccharomyces cerevisiae. 34 21

The effect of L-asparaginase (L-asp) pre-treatment on etoposide-induced DNA strand breakage and cytotoxicity was investigated. In a T-lymphoblastoid cell line, Molt 4, etoposide-induced DNA strand breaks, DNA-protein cross-links and cytotoxicity were reduced by pre-treatment with L-asp for 15 hr, but it did not cause these changes in a promyelocytic-leukemia cell line, HL-60, which is less sensitive than Molt 4 to L-asp. However, pre-treatment of Molt 4 cells with L-asp did not significantly alter the accumulation of [3H]-etoposide. Cell-cycle analyses showed an increase in G1-phase cells, a significant decrease in both S-phase cells and G2/M-phase cells pre-treated with L-asp in Molt 4 cells, but L-asp exposure did not result in any significant changes in HL-60 cells. On the other hand, L-asp pre-treatment did not affect topoisomerase-I (Topo-I) inhibitor, camptothecin (CPT)-induced DNA strand breaks or toxicity in Molt 4 cells. Our data imply that a decrease in S- and G2/M-phase cells following L-asp treatment may explain the reduction of etoposide-induced DNA lesions and cytotoxicity in Molt 4 cells, since topoisomerase-II (Topo-II) content or activity is a function of cellular proliferation status.
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PMID:Pre-treatment of a human T-lymphoblastoid cell line with L-asparaginase reduces etoposide-induced DNA strand breakage and cytotoxicity. 153 31

To elucidate the usefulness in prediction of hypersensitive reactions of L-asparaginase (L-asp), anti-L-asp IgG antibody was measured by two kinds of enzyme-linked immunosolvent assay (ELISA) with improved microplate method and original immunobeads method. The correlation coefficient of both methods matched very well (R = 0.949). Nine out of the 10 patients who were treated with L-asp for the first time showed the elevation of the anti L-asp IgG antibody and returned to normal range within 9 months thereafter. Twenty-two out of 26 patients (84.6%) who had ever developed hypersensitive reactions showed the positive anti-L-asp antibody. There was no positive correlation between the anti-L-asp titer and the severity of the hypersensitive reactions. We concluded that the ELISA with microplate was simple and useful methods to determined the anti-L-asp IgG antibody.
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PMID:[Improved measurements of anti-L-asparaginase IgG antibody and its clinical applications]. 154 12

Between May 1980 and April 1987, 49 children with acute lymphoblastic leukemia (ALL) in isolated testicular and first leukemia relapse (ITR) were enrolled in the Associazione Italiana Ematologia ed Oncologia Pediatrica (AIEOP) multicenter study REC80-ITR. According to the Rome Workshop criteria, 77% were at standard and 23% at high initial prognostic risk. In 33% of the cases, ITR occurred during first treatment. The REC80-ITR protocol consisted of an induction phase regimen of vincristine (VCR), cytarabine (ARA-C), methotrexate (MTX), and asparaginase (L-asp), and bilateral testicular irradiation, and CNS prophylaxis with intrathecal MTX and a maintenance phase with a multidrug rotating regimen. Total treatment duration was 30 months. The median time of observation after ITR was 51 months. The Kaplan-Meier estimates of survival and disease-free survival (DFS) at 4 years were 67.7% and 41%, respectively. Patients who had an ITR on therapy or within the first off-therapy year showed the poorest outcome. The DFS at 3 years was 20%, 47.6%, and 100%, respectively, for children who had an ITR on treatment (n = 16), within the first year of treatment withdrawal (n = 22), or later (n = 10) (P = .001). Patients with an asymptomatic occult testicular infiltrate at treatment discontinuation had a very unfavorable prognosis. Eighty-one percent of second relapses involved the bone marrow. In our experience, children presenting an early ITR (ie, within 6 months of treatment withdrawal) need a very aggressive treatment because of the high probability of an underlying systemic disease. On the other hand, patients with a late ITR seem to have a truly local recurrence and can apparently be cured by standard protocols, as shown in protocol REC80-ITR.
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PMID:Treatment of isolated testicular relapse in childhood acute lymphoblastic leukemia: an Italian multicenter study. Associazione Italiana Ematologia ed Oncologia Pediatrica. 217 80

Treatment of acute lymphoblastic leukaemia (ALL) with L-asparaginase (L-asp) may be associated with thrombotic complications, but the pathogenetic mechanisms of thrombus formation and persistence remain unclear. We studied the procoagulant activity (PCA) of peripheral blood mononuclear cells and some components of the plasma fibrinolytic system in 10 children with ALL undergoing remission induction therapy which includes L-asp. Mononuclear cells obtained 14 days after starting L-asp treatment generated significantly higher amounts of PCA (identified as tissue factor) than cells isolated before the first dose of L-asp and 7 days after the cessation of L-asp administration (p less than 0.01). Augmented PCA coincided with an increase in the plasma D-dimer. The plasma levels of type 1 plasminogen activator inhibitor were found significantly elevated during L-asp therapy (p less than 0.05), whereas plasminogen levels were markedly decreased (p less than 0.05). These findings suggest that, during the course of L-asp treatment, the coagulation-fibrinolysis balance is shifted towards promotion of fibrin formation and deposition. Although it remains to be conclusively established whether L-asp per se or the concurrent administration of multiple chemotherapeutic agents is responsible for these changes, the latter could contribute to the thrombotic complications associated with remission induction therapy for ALL.
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PMID:Unbalanced coagulation-fibrinolysis potential during L-asparaginase therapy in children with acute lymphoblastic leukaemia. 227 27

Thirteen children with ALL and L-asp-induced alterations of the coagulation system were treated with fresh-frozen plasma and antithrombin III (AT III) concentrate. Fresh-frozen plasma was given three times daily to maintain fibrinogen levels greater than 100 mg/dl. AT III concentrate was administered in a continuous infusion over 24 h as long as replacement with fresh-frozen plasma was given. When fibrinogen was greater than 100 mg/dl and AT III less than 80% of normal, only AT III concentrate was administered in a continuous infusion. In all patients treated with the replacement regimen described, fibrinogen levels were maintained greater than 100 mg/dl and AT III levels greater than 80%. No bleeding or thrombosis and no signs of disseminated intravascular coagulation were observed. Our study shows that correction of the alterations of the coagulation system induced by asparaginase can be achieved with a replacement regimen substituting both procoagulant material and the most important inhibitor of the coagulation system.
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PMID:Correction of hemostatic imbalances induced by L-asparaginase therapy in children with acute lymphoblastic leukemia. 315 15

Thirty-four cases of childhood lymphoblastic leukemia that were complicated by CNS and peripheral thrombosis or hemorrhage associated with L-asparaginase (L-asp) therapy were reviewed to determine the effect of the events on the subsequent clinical status. There was no predilection for any site in the CNS cases; all but one of the peripheral events occurred in the lower extremities. The median time for 28 CNS and eight peripheral events from the beginning of L-asp therapy was 17 and 16 days, respectively. One patient died as a result of the CNS event. Twenty-six patients were surviving with a median follow-up of 27 months at the close of the study. Of the patients with peripheral thromboses, only the patient with a dorsal pedal artery occlusion had a significant problem (autoamputation of a toe). Although eight patients received L-asp subsequently without recurrence of the complication, two had transient neurological deterioration associated with the repeat administration of L-asp. Twenty-two patients received CNS prophylaxis consisting of intrathecal methotrexate, CNS radiation, or both, following the CNS event without deterioration. In general, clinical status was not compromised after thrombotic or hemorrhagic events. Although most patients had gross recovery of their neurological impairment, detailed neurological and neuropsychological testing is needed to elucidate possible defects.
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PMID:Sequelae of thrombotic or hemorrhagic complications following L-asparaginase therapy for childhood lymphoblastic leukemia. 317 9

Hemostatic changes in 20 children with acute lymphoblastic leukemia (ALL) who were induced with L-asparaginase (L-asp), vincristine (VCR), and prednisone (PDN) (Group A) were prospectively evaluated. These data were compared with those of a previous group of ALL patients who received L-asp as a single agent during consolidation (Group B). In Group A patients, mean plasma antithrombin activity decreased in the first 2 weeks, though not significantly. Relative to pretreatment values, mean fibrinogen concentration diminished particularly by week 3 (p less than 0.001). Activated partial thromboplastin time (APTT) decreased in the last week as well as after cessation of therapy with L-asp (p less than 0.05). Mean platelet count increased significantly by week 3 (p less than 0.05). Thromboelastograms performed in seven patients confirmed the tendency for thrombosis evidenced by a decreased APTT. Patients in Group B (L-asp alone during consolidation) had decreased concentrations of fibrinogen, AT, and Factors IX and X after L-asp therapy. APTT was prolonged. Our data demonstrate that the tendency for thrombosis is the predominant manifestation of L-asp induced coagulopathy, when the drug is associated with VCR and PDN. Thus the risk/benefit ratio for the use of L-asp early in induction in children with low risk ALL needs to be further evaluated.
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PMID:Hemostatic changes in children with acute lymphoblastic leukemia treated according to two different L-asparaginase schedules. 346 16

Oral glucose tolerance tests were performed in 47 children with acute lymphoblastic leukemia (ALL), treated according to 2 consecutive protocols. Glucose and insulin values were assessed before and after L-asparaginase (L-asp). 30 children (group A) received L-asp as a single-agent consolidation course, after achieving remission with vincristine (VCR) and prednisone (PDN). Normal insulin and glucose levels were found in all patients before L-asp; 4 children (13%) had a transient impaired glucose tolerance (IGT) after completing L-asp therapy. 17 children (group B) were given L-asp during induction therapy with VCR and PDN, and all achieved complete remission. 5 patients (23%) had IGT, without hypoinsulinemia, before L-asp administration. IGT normalized in 4 patients after L-asp, the other children developed a diabetes mellitus. Only 1 patient, with a normal IGT test before L-asp therapy, showed a transient IGT after L-asp. In patients with ALL, the presence of IGT before treatment may be related to leukemia. The concomitant use of steroids does not influence the incidence of IGT in our series. Our data reveal normal insulinemia in patients with IGT. Thus, the leukemic process itself may play a much more significant role in inducing abnormalities in carbohydrate metabolism.
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PMID:Glucose metabolism in children with acute lymphoblastic leukemia treated according to two different L-asparaginase schedules. 644 22


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